Electric actuator, power unit, and electric mobility apparatus equipped with power unit

Abstract

The present invention reduces the power consumption of an electric actuator. An electric actuator (100) is formed that comprises: a motor (10) that is capable of being switched between a positive rotation and a reverse rotation; a detection unit (EN) that detects the rotation position of the motor (10); a servo amplifier (95) that drives the motor (10) in accordance with the rotation position and a command value; and a drive unit (100d) and a crank shaft (70) that have an output shaft mechanically coupled to the rotation shaft of the motor (10), convert the positive rotation and the reverse rotation of the rotation shaft into rotation in one direction, and transmit the rotation to the output shaft. The servo amplifier (95) is such that the command value is set for causing the drive unit (100d) and the crank shaft (70) to rotate the output shaft in one direction when the motor (10) is caused to make the positive rotation and the negative rotation. The command value is determined on the basis of the rotation position of the motor (10) when the motor (10) is rotated by rotating the output shaft in the one direction.

Description

Electric actuator, power unit, and electric mobility equipped with the power unit

[0001] The present invention relates to an electric actuator, a power unit equipped with the electric actuator, and an electric mobility equipped with the electric actuator.

[0002] Electric actuators such as motors are widely used as drive sources for industrial machinery, electric vehicles, etc. To achieve energy conservation in society, there is a strong demand for power saving in drive sources. Related technology is disclosed, for example, in Patent Document 1.

[0003] JP 2017-139839 A

[0004] The electric vehicle described in Patent Document 1 only performs regenerative power generation by the motor generator during coasting or braking, and there is room for improvement.

[0005] Depending on the transmission mechanism that transmits the motor output to the drive shaft of an electric vehicle, there is a strong demand for reducing the power required to drive the motor.

[0006] An object of the present invention is to provide an electric actuator that can achieve power saving, a power unit equipped with the electric actuator, and an electric mobility equipped with the power unit.

[0007] An electric actuator according to one embodiment of the present invention comprises an electric motor capable of switching between forward and reverse rotation, a detection unit that detects the rotational position of the electric motor, a drive unit that drives the electric motor in accordance with the rotational position and a command value, and a transmission mechanism that has an output shaft mechanically coupled to the rotating shaft of the electric motor and converts the forward and reverse rotation of the rotating shaft into rotation in one direction and transmits it to the output shaft.

[0008] In the drive device, a command value is set to rotate the output shaft in one direction in the transmission mechanism when the electric motor is rotated forward and backward.

[0009] The command value is a value determined based on the rotational position of the electric motor that is rotated by rotating the output shaft in one direction.

[0010] According to one embodiment of the present invention, it is possible to achieve power saving in an electric actuator, a power unit equipped with the electric actuator, and an electric mobility equipped with the power unit.

[0011] 7A is a perspective view of an electric actuator according to a first embodiment of the present invention; FIG. 7B is a graph showing the rotation speed [rpm] of the motor in the first half of one cycle of the motor; FIG. 7C is a graph showing the rotation speed of the motor in the second half of one cycle of the motor; FIG. 7D is a graph showing the torque [Nm] of the motor in the first half of one cycle of the motor; and FIG. 7E is a graph showing the torque of the motor in the second half of one cycle of the motor. This figure shows the relationship between frequency F, power running power output from the power regeneration converter to the inverter during power running operation, regenerative power output from the inverter to the power regeneration converter during regenerative operation, and regeneration rate. FIG. 1 is a diagram comparing the operation of a first embodiment of the present invention with that of a conventional motor. FIG. 2 is a diagram explaining a control innovation for an electric actuator according to a second embodiment of the present invention. FIG. 3 is a diagram explaining a control innovation for an electric actuator according to a third embodiment of the present invention. FIG. 4 is a perspective view of an electric actuator according to a fourth embodiment of the present invention. FIG. 5 is a side view of an electric actuator according to the fourth embodiment. FIG. 6 is a plan view of an electric actuator according to the fourth embodiment. FIG. 7 is a front view of an electric actuator according to the fourth embodiment. FIG. 8 is a configuration diagram of a crankshaft of an electric actuator according to the fourth embodiment. FIG. 9 is a block diagram showing a schematic configuration of a power supply system (electric drive system) of an electric actuator according to the fourth embodiment. FIG. 10 is a perspective view of an electric actuator according to a fifth embodiment of the present invention. FIG. 11 is a plan view of an electric actuator according to the fifth embodiment of the present invention. FIG. 12 is a perspective view of an electric actuator according to a sixth embodiment of the present invention. FIG. 13 is a perspective view of an electric actuator according to a seventh embodiment of the present invention. FIG. 14 is a diagram showing the mechanism of a gear device of the seventh embodiment.10. A perspective view of an electric actuator according to an eighth embodiment of the present invention. 11. A block diagram showing a schematic configuration of a power supply system (electric drive system) for an electric actuator according to the eighth embodiment. 12. A block diagram showing a schematic configuration of a power system for an electric vehicle according to a ninth embodiment of the present invention. 13. A block diagram showing a schematic configuration of a power supply system (electric drive system) for an electric vehicle according to the ninth embodiment. 14. A block diagram showing a schematic configuration of a drive mechanism for a railway vehicle according to a tenth embodiment of the present invention. 15. A block diagram showing a schematic configuration of a power supply system (electric drive system) for a railway vehicle according to the tenth embodiment. 16. A plan view of a vibration testing apparatus according to an eleventh embodiment of the present invention. 17. An external view of a tire testing apparatus according to a twelfth embodiment of the present invention. 18. An external view of a tire testing apparatus according to the twelfth embodiment. 19. A diagram showing the internal structure of a torque generating apparatus according to the twelfth embodiment. 20. A block diagram showing a schematic configuration of a power supply system according to the twelfth embodiment. 21. A side view showing the basic configuration of a uniformity and dynamic balancing combined testing apparatus according to a thirteenth embodiment of the present invention. 22. A schematic diagram showing a method of rotationally driving a spindle in the thirteenth embodiment. 23. A front view of a measurement unit of a balance measurement apparatus according to a fourteenth embodiment of the present invention. 24. A side view of the measurement unit of the balance measurement apparatus according to the fourteenth embodiment. 25. A perspective view of a collision simulation testing apparatus according to a fifteenth embodiment of the present invention. 45A is a diagram showing a cam curve discovered by the inventors, and FIG. 45B is a diagram showing a reference cam curve. FIG. 45A is a diagram showing an example of a cam curve for each connecting rod. FIG. 45B is a diagram showing a reference cam curve. FIG. 45A is a diagram showing an example of a cam curve for each connecting rod. FIG. 45B is a diagram showing a modified example of a power unit according to an embodiment. FIG. 45B ...C is a diagram showing an example of a power unit according to an embodiment. FIG. 45C is a diagram showing an example of a cam curve for each connecting rod. FIG. 45D is a diagram showing an example of a power unit according to an embodiment. FIG. 45D is a diagram showing an example of a cam curve for each connecting rod.Fig. 51A is a diagram showing the relationship between frequency and effective load factor in a motor, and Fig. 51B is a diagram showing the relationship between frequency and power consumption in a motor. It is a schematic configuration diagram of an electric vehicle equipped with a power unit. It is a diagram showing the circuit configuration of a power supply system (electric drive system) of a power unit. It is a schematic configuration diagram of a railway vehicle equipped with a power unit. It is a diagram showing the circuit configuration of a power supply system equipped in a railway vehicle.

[0012] The inventors have discovered that the efficiency of using regenerative power can be improved by driving the motor in reverse at a high repetition frequency. The high repetition frequency is, for example, 6 Hz or more, but is not limited to 6 Hz or more.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, identical or corresponding items will be assigned the same or corresponding reference numerals, and duplicate explanations will be omitted. Furthermore, when multiple items with the same reference numerals are displayed in each drawing, not all of the multiple displays will necessarily be assigned the reference numerals, and the assignment of the reference numerals to some of the multiple displays will be omitted as appropriate.

[0014] First Embodiment This electric actuator includes a motor that can switch between forward and reverse rotation, a detector that detects the rotational position of the motor, a drive unit that drives the motor in accordance with the rotational position of the motor and a command value, and a transmission mechanism that has an output shaft mechanically coupled to the rotational shaft of the motor and converts the forward and reverse rotation of the rotational shaft of the motor into rotation in one direction and transmits the rotation to the output shaft. The transmission mechanism may include a first mechanism and a second mechanism.

[0015] The first mechanism in the first embodiment may be a mechanism that has a moving member held so as to be linearly movable, is coupled to the rotation shaft of the motor, and moves the moving member linearly back and forth in response to the forward and reverse rotation of the motor. For example, the first mechanism in the first embodiment may be a mechanism that uses a ball screw, but is not particularly limited as long as it is a mechanism that can move the moving member linearly back and forth in response to the forward and reverse rotation of the rotation shaft of the motor.

[0016] The second mechanism in the first embodiment may include a rotatably held rotating member and a connecting rod rotatably connected to the rotating member at a first connecting portion offset from the rotation center of the rotating member, the connecting rod being rotatably connected to the moving member at a second connecting portion spaced apart from the first connecting portion of the moving member, and the mechanism may rotate the rotating member in one direction in conjunction with the forward and reverse rotation of the motor. For example, the second mechanism in the first embodiment may be a cam mechanism, but is not particularly limited to this as long as it is a mechanism that can rotate the rotating member in one direction in conjunction with the moving member of the first mechanism.

[0017] 1 and 2 are a perspective view and a plan view, respectively, of an electric actuator 100 according to a first embodiment of the present invention. Note that Fig. 2 shows a cross-sectional view of a portion of a piston 50, which will be described later. Fig. 2 also shows a cross-section of a linear motion part (moving member), which will be described later.

[0018] As shown in FIG. 1 , the electric actuator 100 includes a drive unit 100d (first mechanism) and a crankshaft 70 (second mechanism). The electric actuator 100 may further include a servo amplifier 95 (drive device) and a control device 96, which will be described later with reference to FIGS. 5 and 6 . For example, the drive unit 100d and the crankshaft 70 form a transmission mechanism. That is, the transmission mechanism has an output shaft 75 mechanically coupled to the rotary shaft of the motor 10, which will be described later, and converts forward and reverse rotation of the rotary shaft into unidirectional rotation and transmits it to the output shaft 75. The electric actuator 100 may further include a servo amplifier 95 (drive device), a control device 96, and a storage device St, which will be described later with reference to FIG. 42 .

[0019] In this specification, the term "electric actuator" may refer only to a motor and a mechanism driven by the motor, or may refer to a collection of a motor and mechanism (referred to as a mechanism section) plus a drive unit that drives the motor, or may further refer to a device that includes a control unit that controls the drive unit. Furthermore, when an electric actuator includes a drive unit and a control unit, the drive unit and the control unit may be provided in the same housing as the mechanism section, or may be configured as separate devices from the mechanism section and connected to the mechanism section via a cable or the like.

[0020] The drive unit 100 d includes a motor 10 (electric motor), a bearing 30 , a ball screw 40 (feed screw mechanism), a linear motion part 50 (moving member) (hereinafter referred to as “piston 50 ”), and a connecting rod 60 .

[0021] The motor 10 is, for example, an ultra-low inertia, high-output AC servo motor. By using such an ultra-low inertia, high-output motor 10, reciprocating reverse drive at a high frequency of, for example, 100 Hz or more is possible. However, the motor 10 is not limited to an ultra-low inertia, high-output AC servo motor.

[0022] The screw shaft 41 of the ball screw 40 is rotatably supported by a bearing 30 fixed to a frame (not shown). The screw shaft 41 is connected to the rotating shaft 11 of the motor 10 by a shaft coupling 20.

[0023] The piston 50 is a cylindrical member having a hollow portion 50a extending in the direction of the axis Ax1. The axis Ax1 is the center line of the drive unit 100d and is a straight line common to the rotation axes of the motor 10 and the ball screw 40. The nut 42 of the ball screw 40 is housed in, for example, one end (the left end in FIG. 2 ) of the hollow portion 50a of the piston 50 and is fixed to the piston 50.

[0024] A pin 52 is attached to the other end of the piston 50 (the right end in FIG. 2) perpendicular to the axis of the piston 50 (in other words, parallel to the crankshaft 70).

[0025] 3 is a side view of the connecting rod 60. The connecting rod 60 has a small end 62 with a small-diameter pin hole 62a formed therein, a big end 64 (rotating member) with a large-diameter pin hole 64a formed therein, and a rod portion 66 connecting the small end 62 and the big end 64. The pin holes 62a and 64a are formed parallel to each other.

[0026] The pin 52 is inserted into the pin hole 62a of the small end 62, for example, via a bushing (not shown). Both ends of the pin 52 are inserted into a pair of pin holes 50b (FIG. 2) formed in the other end of the piston 50, and fixed to the piston 50. As a result, the connecting rod 60 is connected at the small end 62 to the other end of the piston 50 via the pin 52 so as to be rotatable within a certain angular range around the pin 52 as the rotation axis. In addition to the pin 52 (first pin), the connecting rod 60 is also rotatably connected to a crank pin 72 (second pin), which will be described later.

[0027] 4 is a side view of the crankshaft 70. The crankshaft 70 includes a pair of coaxially arranged crank journals 71 (i.e., with the rotation axis or center line aligned), a crank pin 72 (first connecting portion) arranged eccentrically with respect to the axis of the crank journal 71 (i.e., the rotation axis Ax2 of the crankshaft 70), a pair of crank arms 73 connecting the crank journal 71 and the crank pin 72, a pair of balance weights 74 provided on opposite sides of each crank arm 73 with respect to the rotation axis Ax2, and an output shaft 75 coaxially coupled to one of the crank journals 71. The balance weight 74 is formed to cancel out imbalance caused by the crank pin 72 and crank arm 73 being eccentric with respect to the rotation axis Ax2.

[0028] The crankshaft 70 is a rotating body rotatably supported at a pair of crank journals 71 by a pair of bearings (for example, rolling bearings) (not shown) fixed to a frame (not shown).

[0029] The crank pin 72 is an eccentric pin that is eccentric with respect to the rotation axis of the crankshaft 70, and is inserted into the pin hole 64a of the big end 64 of the connecting rod 60 via, for example, a bushing (not shown). In this way, the crankshaft 70 is rotatably coupled to the connecting rod 60.

[0030] It should be noted that oil-free bushings, for example, are used as the bushings that fit into the pin holes 62a and 64a of the connecting rod 60. Also, instead of bushings, other types of bearings, such as rolling bearings, may be used.

[0031] The motor 10 is driven so that the rotary shaft 11 repeatedly rotates back and forth within a predetermined angular range. That is, the motor 10 repeatedly rotates forward and backward at a predetermined frequency. The rotation of the motor 10 (more specifically, the reciprocating rotary motion, i.e., forward and reverse rotational motion) is converted into linear motion by the ball screw 40 and transmitted to the piston 50. As a result, the piston 50, together with the nut 42 of the ball screw 40, performs a reciprocating linear motion on the axis Ax1 at a predetermined stroke. That is, the ball screw 40 functions as a first motion converter (first mechanism) that converts the reciprocating rotary motion (forward and reverse rotational motion) of the motor 10 into reciprocating linear motion. The reciprocating linear motion of the piston 50 in the direction of the axis Ax1 is transmitted to the eccentric crank pin 72 of the crankshaft 70 by the connecting rod 60 and converted into the rotational motion of the crankshaft 70. That is, the connecting rod 60 and the crankshaft 70 (as well as the pin 52 that rotatably supports the connecting rod 60 and a bearing (not shown) that rotatably supports the crankshaft 70) form a crank mechanism (more specifically, a slider crank mechanism) as a second motion converter that converts reciprocating motion (reciprocating linear motion) into unidirectional rotational motion (hereinafter referred to as "unidirectional rotational motion").

[0032] Fig. 5 is a block diagram showing a schematic configuration of a power supply system 90S (electric drive system 90) that supplies drive power to the motor 10. Fig. 6 is a diagram showing the circuit configuration of the electric drive system 90. The power supply system 90S and the motor 10 constitute the electric drive system 90.

[0033] The primary power source 91 is a commercial power source or a power supply device, and supplies, for example, three-phase AC power. The power supplied from the primary power source 91 (hereinafter referred to as "system power") is supplied to a servo amplifier 95 (drive device) via a circuit breaker 92, an electromagnetic switch 93, and a reactor 94. The servo amplifier 95 is an inverter device that converts the AC supplied from the primary power source 91 into drive power for the motor 10, and supplies the power supplied from the primary power source 91 to the motor 10. The motor 10 is connected to the output terminal of the servo amplifier 95, and drive power is supplied from the servo amplifier 95 to the motor 10. The servo amplifier 95 is connected to a control device 96 so as to be able to communicate with the control device 96, and operates under the control of the control device 96.

[0034] The servo amplifier 95 includes a power regeneration converter 95a, an inverter 95b, and a capacitor 95c. The power regeneration converter 95a is a converter suitable for power regeneration, such as a PWM (Pulse Width Modulation) converter that converts power supply current into a sine wave using PWM control. The power regeneration converter 95a may also be a converter that performs power conversion using a 120° conduction method. The inverter 95b is a PWM inverter that controls the output power using PWM control. In this embodiment, the power regeneration converter 95a rectifies the AC power supplied from the primary power supply 91 during power running (i.e., an operating mode in which the motor 10 is driven by power supplied from the servo amplifier 95) and generates AC power of the same quality as the grid power that is fed back to the primary power supply 91 during regenerative operation. However, a converter dedicated to power running and a converter dedicated to power regeneration may be separately provided.

[0035] The power supply regeneration converter 95a includes switching elements SW1 to SW14, a capacitor C, and a transformer Tr. The inverter 95b includes switching elements SW15 to SW20. The switching elements SW1 to SW20 are, for example, insulated gate bipolar transistors (IGBTs).

[0036] When power is supplied to the motor 10 from a primary power source 91 (for example, a single-phase three-wire commercial power source or a three-phase three-wire commercial power source), the control device 96 repeatedly turns on and off the switching elements SW1 to SW6 in accordance with the frequency of the AC power supplied from the primary power source 91, thereby rectifying the AC power supplied from the primary power source 91.

[0037] When the electric power supplied from the primary power supply 91 is supplied to the motor 10, the electric power is rectified by the switching elements SW1 to SW6 and smoothed by the capacitor C.

[0038] Furthermore, when power is supplied from the primary power supply 91 to the motor 10, the control device 96 repeatedly turns on and off the switching elements SW7, SW10 and the switching elements SW8, SW9, and the power smoothed by the capacitor C is transmitted from the primary coil L1 to the secondary coil L2 of the transformer Tr.

[0039] Furthermore, when power is supplied from the primary power source 91 to the motor 10, the control device 96 repeatedly turns on and off the switching elements SW11, SW14 and the switching elements SW12, SW13 alternately, thereby rectifying the power transmitted from the primary coil L1 to the secondary coil L2.

[0040] Furthermore, when power is supplied from the primary power supply 91 to the motor 10, the power rectified by the switching elements SW11 to SW14 is smoothed by the capacitor 95c.

[0041] Furthermore, when power from the primary power source 91 is supplied to the motor 10, the control device 96 repeatedly turns on and off the switching elements SW15 to SW20, and the power smoothed by the capacitor 95c is converted into AC power with phases that differ by 120 degrees and is supplied to the motor 10.

[0042] Furthermore, when the power regenerated from the motor 10 is supplied to the servo amplifier 95, the AC power supplied from each of the three phases of the motor 10 is rectified by the diodes connected in parallel to the switching elements SW15 to SW20.

[0043] Furthermore, when the power regenerated from the motor 10 is supplied to the servo amplifier 95, the power rectified by the diodes connected in parallel to the switching elements SW15 to SW20 is smoothed by the capacitor 95c.

[0044] Furthermore, when the power regenerated from the motor 10 is supplied to the servo amplifier 95, the control device 96 repeatedly turns on and off the switching elements SW11 and SW14 and the switching elements SW12 and SW13, and the power smoothed by the capacitor 95c is transmitted from the secondary coil L2 of the transformer Tr to the primary coil L1.

[0045] Furthermore, when the power regenerated from the motor 10 is supplied to the servo amplifier 95, the power transmitted from the secondary coil L2 to the primary coil L1 is rectified by the diodes connected in parallel to the switching elements SW7 to SW10.

[0046] Furthermore, when the power regenerated from the motor 10 is supplied to the servo amplifier 95, the power is rectified by the diodes connected in parallel to the switching elements SW7 to SW10 and smoothed by the capacitor C.

[0047] Furthermore, when the power regenerated from the motor 10 is supplied to the servo amplifier 95, the control device 96 repeatedly turns on and off the switching elements SW1 to SW6, and the power (surplus power) that has not been stored in the capacitor C is converted into AC power and supplied to the primary power source 91.

[0048] When driving the motor 10 (power running), the AC power output from the reactor 94 is converted to DC by the power regeneration converter 95a, smoothed by the capacitor 95c, and then converted to AC (e.g., pulse train) drive power by the inverter 95b. The drive power output from the inverter 95b is input to the motor 10 and drives it to rotate.

[0049] When the motor 10 generates regenerative power (during regenerative operation), the regenerative power output from the motor 10 is converted to DC by the inverter 95b and input to the power supply regeneration converter 95a via a DC bus 95d. Note that one DC bus 95d is configured from a pair of positive and negative conductors. The power supply regeneration converter 95a converts the DC power supplied from the DC bus 95d into sine-wave AC and outputs it to the primary power supply 91 via a reactor 94, an electromagnetic switch 93, and a circuit breaker 92.

[0050] FIG. 7A is a graph showing the drive waveform of one cycle of motor 10. FIG. 7B is a simplified graph showing changes in the rotation speed [rpm] of motor 10 during the first half of one cycle of motor 10, and FIG. 7C is a simplified graph showing changes in the rotation speed of motor 10 during the second half of one cycle of motor 10. FIG. 7D is a simplified graph showing changes in the torque [Nm] of motor 10 during the first half of one cycle of motor 10, and FIG. 7E is a simplified graph showing changes in the torque of motor 10 during the second half of one cycle of motor 10. In FIG. 7A, the horizontal axis represents time t, and the vertical axis represents the angular position θ of rotation shaft 11. In FIGS. 7B and 7C, the horizontal axis represents time t, and the vertical axis represents the rotation speed of motor 10. In FIGS. 7D and 7E, the horizontal axis represents time t, and the vertical axis represents the torque of motor 10. The time widths of each of FIGS. 7A to 7E are the same.

[0051] The motor 10 is driven so that the angular position θ of the rotating shaft 11 repeatedly varies in the range of -θa to θa according to a sine wave drive waveform while the time t repeatedly passes from time t0 to time t6. Note that the drive waveform of the motor 10 is not limited to a sine wave. If the drive waveform of the motor 10 is a sine wave drive waveform, the waveform of the motor's rotation speed (number of rotations) will actually be a cosine waveform. However, for ease of explanation, Figures 7B and 7C show the motor's rotation speed waveform in a simplified manner, with a constant speed change in the range of large change and no speed change (constant number of rotations) in the range of small change.

[0052] During section A shown in FIG. 7A , more specifically, during a first period from time t0 to time t1, for example, the rotating shaft 11 accelerates in the positive direction of rotation. That is, during the first period, the rotation speed of the motor 10 increases during forward rotation, and the torque generated at this time is defined as positive torque (acceleration torque). At this time, power is supplied to the motor 10 from the servo amplifier 95 (powering operation). For example, during the first period, power stored in capacitor 95c or capacitor C (or capacitor C1 shown in FIG. 42 , which will be described later) is supplied to the motor 10, and the shortage of power is supplied to the motor 10 from the primary power supply 91.

[0053] During interval B shown in FIG. 7A , more specifically, during a second period from time t2 to time t3, the rotating shaft 11 is decelerated in the positive rotation direction. That is, during the second period, the rotation speed of the motor 10 during forward rotation decreases, generating negative torque (deceleration torque). At this time, regenerative power is supplied from the motor 10 to the servo amplifier 95 (regeneration). For example, during the second period, a portion or substantially all of the power regenerated from the motor 10 is stored in capacitor 95c or capacitor C (or capacitor C1). Note that surplus power regenerated from the motor 10 that is not charged (stored) in capacitor 95c or capacitor C is supplied to the primary power supply 91. That is, the servo amplifier 95 supplies the surplus power overflowing from capacitor 95c or capacitor C (or capacitor C1) to the primary power supply 91, among the regenerative power regenerated in capacitor 95c or capacitor C (or capacitor C1). In other words, the servo amplifier 95 supplies surplus power corresponding to the power consumed by the acceleration of the motor 10 and the regenerated power to the primary power source 91. In further other words, when the motor 10 repeatedly rotates forward and reverse, the servo amplifier 95 outputs to the primary power source 91 the surplus power that is not consumed by the acceleration of the motor 10 out of the regenerated power regenerated from the motor 10.

[0054] During section C shown in FIG. 7A , more specifically, during a third period from time t3 to time t4, for example, the rotating shaft 11 accelerates in the negative direction of rotation. That is, during the third period, the rotation speed of the motor 10 increases during reverse rotation, and the torque generated at this time is defined as positive torque (acceleration torque). At this time, power is supplied to the motor 10 from the servo amplifier 95 (powering operation). For example, during the third period, power stored in capacitor 95c or capacitor C (or capacitor C1) is supplied to the motor 10, and the primary power supply 91 supplies the motor 10 with the power that is sufficient to make up for the power shortfall.

[0055] During interval D shown in FIG. 7A , more specifically, during a fourth period from time t5 to time t6, for example, the rotating shaft 11 is decelerated in the negative rotation direction. That is, during the fourth period, the rotation speed of the motor 10 during reverse rotation decreases, generating negative torque (deceleration torque). At this time, regenerative power is supplied from the motor 10 to the servo amplifier 95 (regenerative operation). For example, during the fourth period, some or all of the power regenerated by the motor 10 is stored in capacitor 95c or capacitor C (or capacitor C1). Note that, of the power regenerated by the motor 10, surplus power not charged (stored) in capacitor 95c or capacitor C (or capacitor C1) is supplied to the primary power supply 91.

[0056] In this way, by repeating power running and regeneration, the power stored in capacitor 95c or capacitor C (or capacitor C1) during regeneration can be used to drive motor 10 during the next power running operation, thereby reducing the power supplied to motor 10 from primary power supply 91 during the next power running operation. This allows for power savings in electric drive system 90 and electric actuator 100, which will be described later. Furthermore, by repeating acceleration (power running operation) and deceleration (regenerative operation) while alternating directions, the rotating shaft 11 of motor 10 rotates back and forth. Such back and forth rotation is repeated at a frequency of, for example, a maximum of 500 Hz.

[0057] As described above, in this embodiment, in order to cause the motor 10 to repeatedly accelerate and decelerate, the supply of power to the motor 10 and the generation of regenerative power by the motor 10 are alternately repeated. Short-term (e.g., about one cycle of the motor 10) voltage fluctuations on the DC bus 95d caused by the exchange of power between the capacitor 95c, the capacitor C (or the capacitor C1), and the primary power supply 91 and the motor 10 are adjusted (in other words, leveled) mainly by the capacitor 95c. Therefore, part or all of the power supplied to the motor 10 in sections A and C is recovered and reused as regenerative power in sections B and D, making it possible to drive the motor 10 while suppressing the power consumption of the primary power supply 91.

[0058] Table 1 shows the driving conditions and power consumption measurement results of the electric actuator 100 of this embodiment.

[0059] "Frequency F" is the number of times per second one cycle of driving shown in Figure 7 is repeated. Power consumption was measured by varying frequency F from 25 Hz to a maximum of 200 Hz in 25 Hz increments. However, the minimum frequency was set to 10 Hz, which allows stable operation, rather than 0 Hz.

[0060] "Torque T ０ " is the maximum value (amplitude) of the relative torque (the ratio to the rated torque expressed as a percentage) of the rotating shaft 11 of the motor 10.

[0061] "Power consumption value W Ａ " is the average power consumption of the entire electric drive system 90 measured by power meter I upstream of the circuit breaker 92 (FIG. 5).

[0062] Output power value W Ｂ " is the average value of the power output from the servo amplifier 95 to the motor 10.

[0063] The "energy saving rate R" is the percentage of power consumption reduced by reusing regenerative power, and is expressed as R = 100 × (1 - W Ａ / W Ｂ ) is calculated by

[0064] It has been confirmed that by using the electric actuator 100 of this embodiment, an energy saving rate of over 70% can be achieved at frequencies F of 200 Hz or less. In particular, it has been confirmed that an energy saving rate of over 90% can be achieved in the low frequency range of 75 Hz or less.

[0065] The effect of reducing power consumption by the electric actuator 100 of this embodiment can be obtained even when the repetition frequency of the reciprocating rotation of the motor 10 is 1 Hz, but when the repetition frequency is set to 3 Hz or higher (more preferably 5 Hz or higher), the regenerative power can be efficiently reused by the electric actuator 100 itself, resulting in a good energy saving rate.

[0066] FIG. 8 shows the relationship between the frequency F, the running power Pp output from the power regeneration converter 95a to the inverter 95b during power running, the regenerative power Pr output from the inverter 95b to the power regeneration converter 95a during regenerative operation, and the regeneration rate. The white bars in FIG. 8 represent the running power Pp [W], and the black bars represent the regenerative power Pr [W]. The broken line in FIG. 8 represents the regeneration rate [%], which indicates the ratio of the regenerative power Pr to the running power Pp. Furthermore, no loads, such as the ball screw 40, piston 50, or crankshaft 70, are connected to the rotating shaft 11 of the motor 10. Therefore, the only positive or negative torque generated in the motor 10 during power running or regenerative operation is the positive or negative torque generated by the weight of the rotor and rotating shaft 11 within the motor 10.

[0067] As shown in Figure 8, when the frequency F is 1 to 5 Hz, the regeneration rate is 40% or less, but when the frequency F is 6 Hz or higher, the regeneration rate is 50% or approximately 50%. Thus, when the motor 10 is repeatedly rotated forward and backward at a frequency F of 6 Hz or higher, the regeneration rate can be higher than when the motor 10 is repeatedly rotated forward and backward at a frequency F of 1 to 5 Hz, thereby improving the energy-saving effect. Furthermore, when a relatively large load, such as the ball screw 40, piston 50, or crankshaft 70, is connected to the rotating shaft 11, the positive or negative torque generated in the motor 10 during regenerative operation can be larger than when no load is connected to the rotating shaft 11, thereby further increasing the regeneration rate and further improving the energy-saving effect.

[0068] FIG. 9A is a graph that schematically shows the drive waveform of a typical conventional motor, and FIG. 9B is a graph that schematically shows the drive waveform of the motor 10 of this embodiment.

[0069] As shown in FIG. 9A, in a typical conventional motor drive, the period T １ After accelerating to a predetermined rotation speed in the period T ２ ), and at the end, it is decelerated and stopped (section T ３ In this type of driving, the regenerative power is ３ Therefore, the effect of reducing power consumption by using regenerative power is small.

[0070] On the other hand, in this embodiment, as shown in FIG. 9B , acceleration (powering operation) and deceleration (regenerative operation) of the motor 10 are repeated at a high frequency throughout the entire period from the start to the end of driving. Regenerative power generated during deceleration is immediately consumed in the next powering operation. In other words, the generation and consumption of regenerative power is constantly repeated from the start to the end of driving. As a result, in this embodiment, the use of regenerative power has an extremely significant effect on reducing power consumption.

[0071] As described above, the electric actuator 100 according to this embodiment is provided with a motion converter (transmission mechanism) that converts the forward and reverse rotational motion output by the motor 10 into unidirectional rotational motion, thereby making it possible to output unidirectional rotational motion while actively generating regenerative energy by rotating the motor 10 forward and reverse. Therefore, the unidirectional rotational motion used in mobility devices such as automobiles and trains can be obtained with less power consumption than when it is obtained directly from the rotating shaft of the motor 10.

[0072] Second Embodiment Fig. 10 is a diagram illustrating a control technique for an electric actuator according to this embodiment. Fig. 10A shows a control example for the electric actuator 100 according to the first embodiment, and Fig. 10B shows a control example for the electric actuator according to this embodiment.

[0073] 10A and 10B, the vertical axis indicates the position of the piston 50 performing reciprocating linear motion. Position 100 and position −100 indicate the positions of the piston 50 when the slider crank mechanism of the electric actuator is at the bottom dead center and top dead center, respectively.

[0074] 10A and 10B, the horizontal axis indicates the phase of the crankshaft 70, which rotates in one direction. Phase 90 and Phase 270 indicate the phase of the crankshaft 70 when the slider-crank mechanism of the electric actuator is at the bottom dead center and the top dead center, respectively.

[0075] The configuration of the electric actuator according to this embodiment is the same as that of the electric actuator 100 according to the first embodiment, except that the control device 96 is configured to be able to control the motor 10 (phase shift control), which will be described later. Therefore, in the electric actuator according to this embodiment, the reciprocating rotational motion of the motor 10 is also converted into reciprocating linear motion by the ball screw 40, and this reciprocating linear motion is further converted into unidirectional rotational motion by the slider crank mechanism and output. The sine wave waveforms in Figures 10A and 10B show the relationship between the position of the piston 50 and the phase of the crankshaft 70 in these electric actuators.

[0076] 10A , in the electric actuator 100 according to the first embodiment, the control device 96 controls the servo amplifier 95 so as to switch the rotation direction of the motor 10 from forward to reverse at timing t1 when the piston 50 reaches bottom dead center, and to switch the rotation direction of the motor 10 from reverse to forward at timing t2 when the piston 50 reaches top dead center. This makes it possible to convert reciprocating linear motion into rotational motion while maintaining the rotation direction of the crankshaft 70 by inertia at dead centers (top dead center, bottom dead center) where no rotational force is generated in the crankshaft 70 due to the movement of the piston 50. In other words, it is possible to convert reciprocating linear motion into rotational motion in one direction.

[0077] Incidentally, when switching between forward and reverse rotation of motor 10, a large torque is generated in motor 10. For this reason, when the direction of rotation is switched between top dead center and bottom dead center, where the force transmitted from piston 50 to crankshaft 70 is not applied in the tangential direction (rotational direction) but is transmitted only radially, the large torque generated by motor 10 generates a large radial force on crankshaft 70. As a result, vibrations occur in crankshaft 70, which may hinder smooth rotation of crankshaft 70.

[0078] In the electric actuator according to this embodiment, taking these circumstances into consideration, the control device 96 controls the servo amplifier 95 to switch the rotation of the motor 10 between forward and reverse rotation, avoiding timing t1 when the piston 50 reaches bottom dead center and timing t3 when the piston 50 reaches top dead center. For example, as shown in FIG. 10B , the control device 96 may control the servo amplifier 95 to switch the rotation direction from forward to reverse at timing t3, which is slightly later than timing t1 when the piston 50 reaches bottom dead center, and to switch the rotation direction from reverse to forward at timing t4, which is slightly later than timing t2 when the piston 50 reaches top dead center. Note that this time difference (t3-t1, t4-t2) corresponds to, for example, approximately 0.5 degrees of the phase of the crankshaft 70, and the displacement occurring therebetween is generally within the range of the play (gap) of the crank mechanism. Note that the time difference (t3-t1, t4-2) can be 1.5 degrees or less, and preferably 1 degree or less, of the phase of the crankshaft 70. Furthermore, it is more desirable to set it to 0.5 degrees or less.

[0079] In this way, by controlling the motor 10 so that the rotation direction is switched at positions shifted from the top dead center and the bottom dead center, it is possible to apply a rotational force at the top dead center and the bottom dead center while suppressing the force applied in the radial direction of the crankshaft 70. Therefore, the electric actuator according to this embodiment can output smoother unidirectional rotation while suppressing vibrations more than the electric actuator 100 according to the first embodiment.

[0080] Specific control methods include a method of giving a constant phase difference to the phase of the control of the motor 10 relative to the phase of the crankshaft 70 throughout the entire control period, and a method of gradually increasing and decreasing (eliminating) the phase difference near the dead center (top dead center, bottom dead center) (for example, within a range of ±10° around the dead center).

[0081] Although FIG. 10B shows an example in which the rotation direction is switched after passing the top dead center and the bottom dead center, the control device 96 may also control the servo amplifier 95 so that the rotation direction is switched before passing the top dead center and the bottom dead center.

[0082] Third Embodiment Fig. 11 is a diagram illustrating a control technique for an electric actuator according to this embodiment. Fig. 11A is a diagram showing the relationship between the position of the piston 50 and the phase of the crankshaft 70 in the electric actuator according to this embodiment, and Fig. 11B is a diagram showing the relationship between torque limit and the phase of the crankshaft 70 in the electric actuator according to this embodiment.

[0083] The configuration of the electric actuator according to this embodiment is the same as the configuration of the electric actuator 100 according to the first embodiment, except that the control device 96 is configured to be able to execute control (load suppression control) of the motor 10, which will be described later.

[0084] As described above in the second embodiment, when the rotation direction of the motor 10 is switched between the top dead center and the bottom dead center, a large force is applied in the radial direction of the crankshaft 70, which tends to cause vibration in the crankshaft 70. Therefore, in this embodiment, the control device 96 controls the servo amplifier 95 so that the torque of the motor 10 is limited at least when the dead center (top dead center, bottom dead center) is reached. For example, as shown in FIG. 11 , the control device 96 controls the torque of the motor 10 in the vicinity of the top dead center and the bottom dead center (θ １ ~θ ２ , θ ３ ~θ ４ ) the torque of the motor 10 may be limited to control the motor 10 within the limited torque range. This prevents excessive force from being applied to the crankshaft 70 in the radial direction, thereby suppressing the generation of vibrations that impede the smooth rotation of the crankshaft 70. Therefore, the electric actuator according to this embodiment can output smoother unidirectional rotation while suppressing vibrations more effectively than the electric actuator 100 according to the first embodiment.

[0085] <Fourth Embodiment> The electric actuator 100 of the first embodiment described above is equipped with a single drive unit 100d, but the electric actuator may be provided with multiple drive units. An electric actuator 200 according to a fourth embodiment of the present invention, which will be described next, is equipped with four drive units 200d. The electric actuator 200 may also include a servo amplifier 295 (drive device) and a control device 296, which will be described later with reference to FIG. 17.

[0086] Fig. 12 is a perspective view of an electric actuator 200 according to a fourth embodiment of the present invention. Figs. 13 to 15 are a side view, a plan view, and a front view, respectively, of the electric actuator 200. Fig. 16 is a configuration diagram of a crankshaft 270 of the electric actuator 200.

[0087] An electric actuator 200 according to a fourth embodiment of the present invention is a four-cylinder actuator that mimics the structure of a four-cylinder engine, and includes a crankshaft 270 and four drive units 200d connected to the crankshaft 270. In other words, the electric actuator 200 includes four electric motors, four first motion converters, and four second motion converters, and as will be described later, the four second motion converters share an output shaft for unidirectional rotational motion. The electric actuator 200 further includes a servo amplifier 295 (drive device) and a control device 296, which will be described later with reference to FIG. 17 .

[0088] Each drive unit 200d has a structure similar to that of the drive unit 100d of the first embodiment, and includes a motor 10, a shaft coupling 20, a bearing 30, a ball screw 40, a piston 250, and a connecting rod 260, as shown in FIG.

[0089] As shown in Fig. 13, the motor 10 is fixed to a frame 220 that houses a shaft coupling 20, and the frame 220 is fixed on the base 210. As shown in Fig. 14, the output shaft of the motor 10 is connected by the shaft coupling 20 to the shaft of a ball screw 40 that is supported by a bearing 30 provided on the frame 220.

[0090] A piston 250 is fixed to the nut of the ball screw 40. As shown in Figure 13, the piston 250 is placed on a carriage 242 that is movable along a rail 241 that is arranged on the upper surface of the frame 230 in parallel with the axis of the ball screw 40. By arranging the piston 250 on the carriage 242 in this way, the linear movement of the piston 250 is guided by the rail 241 and the carriage 242. This prevents excessive bending stress from being applied in the vertical direction to the ball screw 40 when the piston 250 makes a reciprocating linear movement.

[0091] As shown in Figures 13 and 14, an end 251 of the piston 250 is rotatably connected to one end (clevis portion) of a connecting rod 260 by a pin 252 (first pin). This allows the connecting rod 260 to rotate within a certain angular range around the pin 252 as a rotation center axis in accordance with the reciprocating linear motion of the piston 250. In addition, the other end of the connecting rod 260 is rotatably connected to a crankshaft 270 by a crank pin 273, as shown in Figures 14 and 15.

[0092] The crankshaft 270 is a rotating body and has a structure that imitates a crankshaft for a four-cylinder engine. As shown in FIG. 16, the crankshaft 270 is made up of multiple parts that are fixed together with bolts. With this configuration, it is possible to easily configure a crankshaft that is compatible with any number of drive units d, not just four-cylinder types.

[0093] 15 and 16 , the crankshaft 270 specifically includes crank journals (crank journals 271 and 272) supported by bearings provided in bearing portions (bearing portions 281 and 282) erected on the base 210, a crank pin 273 rotatably connected to the connecting rod 260, and a crank arm 274 that joins the crank pin 273 at a position eccentric to the axis of the crank journal. The crank pin 273 is an eccentric pin that is eccentric to the rotation axis of the crankshaft 270.

[0094] Each of the crank journals 271 , 272 and the crank pin 273 is fixed to a crank arm 274 with a bolt, and the crank journals 271 , 272 and the crank pin 273 are further connected via the crank arm 274 .

[0095] The crankshaft 270 includes two types of crank journals: a crank journal 271 having an output shaft, and a crank journal 272 sandwiched between crank arms 274. The crank journal 272 sandwiched between crank arms 274 is made up of two parts (crank journal 272a and crank journal 272b) so that it can be inserted into a bearing, and after one part (crank journal 272a) is inserted into the bearing, it is fixed to the other part (crank journal 272b) with a bolt.

[0096] In the electric actuator 200 configured as described above, the reciprocating rotational motion of the motor 10 is converted into the reciprocating linear motion of the piston 250 by the ball screw 40. Furthermore, the connecting rod 260 and the crankshaft 270 form a slider crank mechanism, which converts the reciprocating linear motion of the piston 250 into the unidirectional rotational motion of the crankshaft 270. In other words, like the electric actuator 200 of the first embodiment, the electric actuator 200 is configured to convert the reciprocating rotational motion of the motor 10 into the unidirectional rotational motion and output it.

[0097] The electric actuator 200 differs from the electric actuator 100 in that the connecting rods 260 of the four drive units 200d are rotatably fitted to the four crank pins 273 of the crankshaft 270. In the electric actuator 200, the crankshaft 270 is rotationally driven by the four drive units 200d connected to the crankshaft 270. In other words, the four drive units 200d share the crankshaft 270, which is the output shaft of the unidirectional rotational motion output by each crank mechanism, and the power generated by the four drive units 200d is combined at the crankshaft 270. In this respect as well, the electric actuator 200 differs from the electric actuator 100.

[0098] The eccentric directions of the four crank pins 273 included in the crankshaft 270 are not particularly limited, and may be different from one another. For example, the eccentric directions of the four crank pins 273 may be alternately shifted by 180°. Furthermore, the eccentric directions of the four crank pins 273 may be shifted by 90°, for example, so that the timing at which the four crank pins 273 reach their dead centers does not coincide. This may eliminate the time when no rotational force is applied to the crankshaft 270, thereby achieving smooth rotation.

[0099] 17 is a block diagram showing a schematic configuration of a power supply system 290S (electric drive system 290) of an electric actuator 200 according to a fourth embodiment of the present invention. The power supply system 290S constitutes the electric drive system 290 together with four drive units 200d (specifically, motors 10).

[0100] The electric drive system 290 and power supply system 290S of the fourth embodiment differ from those of the first embodiment in that they include a plug 291 that plugs into a primary power source outlet (not shown) and in the configuration of the servo amplifier. The servo amplifier 295 of the fourth embodiment includes a battery 295e and four inverters 95b corresponding to each of the four drive units 200d. By including the battery 295e, the electric actuator 200 of the fourth embodiment can operate using power stored in the battery 295e even when disconnected from the primary power source. The battery 295e is connected in parallel to the power regeneration converter 95a and the four inverters 95b to a DC bus 95d consisting of a pair of conductors. The motor 10 of the corresponding drive unit 200d is connected to each inverter 95b.

[0101] The four inverters 95b are connected in parallel to one another and to a common DC bus 95d. That is, DC power generated by the power supply regeneration converter 95a, the battery 295e, and the capacitor 95c is distributed to the four inverters 95b. In addition, regenerated power output from the four inverters 95b is combined at the DC bus 95d. A portion of the regenerated power returned to the DC bus 95d is again distributed to the four inverters 95b. In addition, surplus regenerated power is stored in the capacitor 95c and the battery 295e, or returned to the primary power supply via the power supply regeneration converter 95a.

[0102] If the eccentric directions of the four crank pins 273 are changed by 90° (i.e., if the eccentric directions of the four crank pins 273 are the 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock directions), the motors 10 of the two drive units 200d connected to the crank pins 273 eccentric to the 12 o'clock and 6 o'clock directions of the crankshaft 270 and the motors 10 of the remaining two drive units 200d connected to the crank pins 273 eccentric to the 3 o'clock and 9 o'clock directions will have opposing timings for consuming and regenerating power, and therefore most of the regenerated power output from the motors 10 of one of the two drive units 200d will be efficiently consumed by the motors 10 of the other two drive units 200d. This makes it possible to drive the electric actuator 200 with lower power consumption.

[0103] Fifth Embodiment Fig. 18 is a perspective view of an electric actuator 201 according to a fifth embodiment of the present invention. Fig. 19 is a plan view of the electric actuator 201.

[0104] As shown in FIG. 18 , an electric actuator 201 according to a fifth embodiment of the present invention includes a crankshaft 270a and two drive units 200d connected to the crankshaft 270a. The drive units 200d are as described above in the fourth embodiment, and detailed description thereof will be omitted. In other words, the electric actuator 201 includes two electric motors, two first motion converters, and two second motion converters, and the two second motion converters share an output shaft for unidirectional rotational motion. Note that the electric actuator 201 may include a servo amplifier 295 (drive device) and a control device 296, similar to the electric actuator 200.

[0105] The crankshaft 270a has a structure that imitates a crankshaft for a two-cylinder engine. Like the crankshaft 270 of the fifth embodiment, the crankshaft 270a is made up of multiple parts that are fixed to each other with bolts.

[0106] Specifically, as shown in FIG. 19 , the crankshaft 270a includes crank journals (crank journals 271 and 272) supported by bearings provided in bearing portions (bearing portions 281 and 282) erected on the base 210, a crank pin 273 rotatably connected to the connecting rod 260, and a crank arm 274 that joins the crank pin 273 at a position eccentric to the axis of the crank journal. Note that the crankshaft 270a differs from the crankshaft 270 in that the number of parts is reduced due to the reduced number of cylinders (number of drive units). For example, only one crank journal 272 is provided between the cylinders, and only two crank pins 273 are provided per cylinder.

[0107] In the first to fifth embodiments described above, a crank mechanism (slider crank mechanism) consisting of a connecting rod and a crankshaft is used as the second motion converter that converts reciprocating motion (reciprocating linear motion) into unidirectional rotational motion, but the present invention is not limited to this configuration. Below, an embodiment that does not use a crankshaft will be described.

[0108] 20 is an external view of an electric actuator 300 according to a sixth embodiment of the present invention. The electric actuator 300 of this embodiment includes a base 304, and a drive unit 300d and a spindle portion 370 that are installed on the base 304. Note that the electric actuator 300 may also include a servo amplifier and a control device (not shown), similar to the electric actuators according to the above-described embodiments.

[0109] The drive unit 300d includes a motor 10, a ball screw 40 that converts the rotational motion of the motor 10 into linear motion, a bearing 30 that rotatably supports a screw shaft 41 of the ball screw 40, a box-shaped linear motion unit 350 (hereinafter referred to as the "piston 350") that is movable in the axial direction (i.e., the extension direction of the axis Ax1), a guideway-type circulating linear bearing 354 (hereinafter referred to as the "linear guide 354") that supports the piston 350 movably in the axial direction, a connecting rod 360 that connects the piston 350 to a spindle 372 of the spindle unit 370 (described later), and frames 305 and 306 attached to a base 304. The motor 10 and the bearing 30 are attached to the frame 305. Note that the axis Ax1 of the drive unit 300d in this embodiment is a straight line common to the center lines of the rotation shaft 11 of the motor 10 and the screw shaft 41 of the ball screw 40.

[0110] The linear guide 354 includes a rail 354a and a carriage 354b that can run on the rail 354a. The rail 354a is attached to the upper surface of the frame 306, and the carriage 354b is attached to the lower surface of the piston 350. This supports the piston 350 so that it can move only in the axial direction relative to the base 304.

[0111] The rotating shaft 11 (not shown) of the motor 10 is connected to the screw shaft 41 of the ball screw 40 by the shaft coupling 20. The nut 42 (not shown) of the ball screw 40 is housed in the hollow portion of the piston 350 and fixed to the piston 350. As the rotating shaft 11 of the motor 10 rotates back and forth, the piston 350 moves back and forth in the axial direction. A clevis 351 is provided at one end of the piston 350 in the axial direction.

[0112] The spindle portion 370 includes a spindle 372, which is a rotating body, and a bearing portion 374 that rotatably supports the spindle 372. A pin 372p is eccentrically attached to one end surface of the spindle 372. In other words, the pin 372p is an eccentric pin that is eccentric with respect to the rotation axis of the spindle 372.

[0113] In this embodiment, ball joints 362 are provided at both ends of the connecting rod 360. One of the ball joints 362 is connected to the clevis 351 via a pin 52 so as to be rotatable around the pin 52. The other ball joint 362 is connected to the spindle 372 via a pin 372p so as to be rotatable around the pin 372p. Note that a rolling bearing such as a self-aligning roller bearing or a self-aligning ball bearing may be used instead of the ball joint 362.

[0114] The motor 10 is driven so that the rotary shaft 11 repeatedly rotates back and forth within a predetermined angular range. The rotation of the motor 10 is converted into linear motion by the ball screw 40 and transmitted to the piston 350. As a result, the piston 350 performs a linear reciprocating motion on the axis Ax1 at a predetermined stroke. In other words, the ball screw 40 functions as a first motion converter that converts the reciprocating rotational motion output from the motor 10 into reciprocating linear motion. The reciprocating linear motion of the piston 350 in the direction of the axis Ax1 is transmitted to the pin 372p by the connecting rod 360 and converted into unidirectional rotational motion of the spindle 372. In other words, the connecting rod 360 and the spindle 372 form a link mechanism that functions as a second motion converter that converts reciprocating motion (reciprocating linear motion) into unidirectional rotational motion.

[0115] Seventh Embodiment The first mechanism in the seventh embodiment, like the first mechanism in the first embodiment, may have a moving member held so as to be linearly movable, be coupled to the rotation shaft of a motor, and linearly reciprocate the moving member in response to forward and reverse rotation of the motor. For example, a mechanism using a ball screw may be considered as the first mechanism in the seventh embodiment, but the first mechanism is not particularly limited as long as it is a mechanism that can linearly reciprocate the moving member in response to forward and reverse rotation of the rotation shaft of the motor.

[0116] Furthermore, the second mechanism in the seventh embodiment, like the second mechanism in the first embodiment, may include a rotatably held rotating member and a connecting rod rotatably connected to the rotating member at a first connecting portion offset from the rotation center of the rotating member, the connecting rod being rotatably connected to the moving member at a second connecting portion spaced apart from the first connecting portion of the moving member, and may rotate the rotating member in one direction in conjunction with the forward and reverse rotation of the motor. For example, a cam mechanism may be considered as the second mechanism in the seventh embodiment, but the second mechanism is not particularly limited as long as it is a mechanism that can rotate the rotating member in one direction in conjunction with the moving member of the first mechanism.

[0117] FIG. 21 is an external view of an electric actuator 400 according to a seventh embodiment of the present invention. The electric actuator 400 of this embodiment includes two drive units 400d (first mechanisms) arranged side by side and a gear device 470 (second mechanism) connected to the two drive units 400d. As with the electric actuators of the above-described embodiments, the electric actuator 400 may include a servo amplifier and a control device (not shown). Note that the drive unit 400d of this embodiment differs from the drive unit 100d of the first embodiment or the drive unit 300d of the sixth embodiment in that the frames 405 of the two drive units 400d are integrated. However, the other configurations are the same as those of the drive unit 100d or the drive unit 300d. For example, a transmission mechanism is formed by the two drive units 400d and the gear device 470. That is, the transmission mechanism has a second shaft 475 (output shaft) (described later) that is mechanically coupled to the rotating shaft of the motor 10 (electric motor), and converts the forward and reverse rotation of the rotating shaft into unidirectional rotation and transmits it to the second shaft 475. The electric actuator 400 may further include a servo amplifier 95 (drive device), a detector EN, a control device 96, and a memory device St shown in FIG. 42 . Furthermore, each of the two drive units 400d may include a motor 10, a bearing 30, a ball screw 40 (feed screw mechanism), a piston 50 (moving member), and a connecting rod 60.

[0118] Furthermore, in the seventh embodiment, the motor 10 is driven by a command value determined based on a cam curve (solid line) shown in Fig. 46, which will be described later. This allows the output shaft 75 to rotate without applying an unnecessary load to the motor 10, thereby enabling the electric actuator 500 to consume less power.

[0119] Fig. 22 is a diagram showing the mechanism of the gear device 470. Fig. 22 also shows the connecting rod 360 of the drive unit 300d or the drive unit 400d. The connecting rod 360 and the piston 50 are connected by a pin 52 (second connecting portion).

[0120] The gear device 470 includes a case 471 ( FIG. 21 ), two pairs of bearings 473 and 476 attached to the case 471, a first shaft 472 (input shaft) rotatably supported by the pair of bearings 473, a drive gear 474 attached to the first shaft 472, a second shaft 475 (output shaft) rotatably supported by the pair of bearings 476, and a driven gear 477 attached to the second shaft 475. The drive gear 474 meshes with the driven gear 477, and the rotational motion of the first shaft 472 is transmitted to the second shaft 475 via the drive gear 474 and the driven gear 477.

[0121] A disk portion 472a (rotating member) is provided at each end of the first shaft 472. A pin 472p (first connecting portion) is eccentrically attached to each disk portion 472a. That is, the electric actuator 400 has a rotatably held disk portion 472a and a connecting rod 360 rotatably connected to the disk portion 472a by a pin 472p offset from the rotation center of the disk portion 472a. The connecting rod 360 is rotatably connected to the piston 50 by a pin 52, and rotates the disk portion 472a in one direction in conjunction with the forward and reverse rotation of the motor 10. Note that, in this embodiment, the eccentric directions of the pins 472p of the two disk portions 472a are offset by 90 degrees.

[0122] The connecting rod 360 of one drive unit 400d is connected to a pin 472p of one disk portion 472a of the first shaft 472, and the connecting rod 360 of the other drive unit 400d is connected to a pin 472p of the other disk portion 472a of the first shaft 472. Therefore, the power output from the pair of drive units 400d is combined in the gear device 470 (more specifically, the first shaft 472) and output from the second shaft 475.

[0123] In this embodiment, the eccentric directions of the pins 472p of the two disk portions 472a that are respectively coupled to the connecting rods 360 of the two drive units 400d are offset by 90 degrees. Therefore, the motors 10 of the two drive units 400d consume / regenerate power at opposite times, so that most of the regenerated power output from the motor 10 of one drive unit 400d is efficiently consumed by the motor 10 of the other drive unit 400d. This makes it possible to drive the electric actuator 400 with lower power consumption.

[0124] Furthermore, in the seventh embodiment, the motors 10 of the two drive units 400d are driven by command values ​​determined based on the cam curve (solid line) shown in Fig. 43, which will be described later. This allows the output shaft 75 to rotate without placing an unnecessary load on each motor 10, thereby enabling the electric actuator 400 to consume less power.

[0125] In the first to seventh embodiments described above, a configuration is adopted in which reciprocating rotary motion is first converted into reciprocating linear motion by a first motion converter, and then further converted into unidirectional rotary motion by a second motion converter. However, the present invention is not limited to this configuration, and a configuration in which reciprocating rotary motion is directly converted into unidirectional rotary motion, as in the eighth embodiment of the present invention described next, is also included in the scope of the present invention.

[0126] Eighth Embodiment The first mechanism in the eighth embodiment has a first rotating member fixed to the rotation shaft of a motor. Note that the first mechanism applied to the eighth embodiment is not particularly limited as long as it is a mechanism having a first rotating member fixed to the rotation shaft of a motor.

[0127] The second mechanism applied to the eighth embodiment includes a rotatably held second rotating member and a connecting rod rotatably connected to the second rotating member at a first connecting portion offset from the rotation center of the second rotating member, the connecting rod being rotatably connected to the first rotating member at a second connecting portion away from the rotation center of the first rotating member, and rotating the second rotating member in one direction in conjunction with forward and reverse rotation of the motor. Note that the second mechanism in the eighth embodiment is not particularly limited as long as it is a mechanism that can rotate the second rotating member in one direction in conjunction with the first rotating member of the first mechanism.

[0128] FIG. 23 is an external view of an electric actuator 500 according to an eighth embodiment of the present invention. The electric actuator 500 of this embodiment includes a base 504, a drive unit 500d (first rotation mechanism) and a spindle unit 570 (second rotation mechanism) installed on the base 504. The electric actuator 500 may also include a servo amplifier 95 and a control device 96 shown in FIG. 24. The electric actuator 500 may also include a servo amplifier 95, a detection unit EN, a control device 96, and a storage device St shown in FIG. 42 (described later). The drive unit 500d includes a motor 10 (electric motor), a drive disk 550 (first disk unit, first rotating member) coupled to the rotating shaft 11 of the motor 10, and a connecting rod 560. A pin 552 (second connecting unit, first pin) is eccentrically attached to the drive disk 550. That is, the electric actuator 500 includes the drive disk 550 fixed to the rotating shaft of the motor 10. The electric actuator 500 may further include a servo amplifier 95 (drive device), a detector EN, a control device 96, and a memory device St, all of which are shown in FIG. 42 and will be described later.

[0129] The spindle unit 570 includes a spindle 572 and a bearing unit 574 that rotatably supports the spindle 572. The spindle 572 includes a cylindrical shaft unit 572b, a driven disk 572a (second disk unit, second rotating member) coupled to one end of the shaft unit 572b, and a pin 572p (first connecting unit, second pin) eccentrically attached to the driven disk 572a. That is, the electric actuator 500 includes the rotatably held driven disk 572a and a connecting rod 560 that is rotatably connected to the driven disk 572a by the pin 572p that is offset from the rotation center of the driven disk 572a. The connecting rod 560 is rotatably connected to the driving disk 550 by the pin 552 that is offset from the rotation center of the driving disk 550, and rotates the driven disk 572a in one direction in conjunction with the forward and reverse rotation of the motor 10.

[0130] Ball joints 562 are provided at both ends of the connecting rod 560. One ball joint 562 is connected to the driving disk 550 via a pin 552 so as to be rotatable around the pin 552. The other ball joint 562 is connected to the driven disk 572a (spindle 572) via a pin 572p so as to be rotatable around the pin 572p. In other words, the connecting rod 560 is connected to the driving disk 550 (pin 552) and the driven disk 572a (pin 572p) by joints (pairs). Note that rolling bearings such as self-aligning roller bearings or self-aligning ball bearings may be used instead of the ball joints 562.

[0131] The motor 10 is driven so that the rotating shaft 11 (and the driving disk 550) repeatedly rotates back and forth within a predetermined angular range. This causes the connecting rod 560 to be repeatedly pushed and pulled in the longitudinal direction by a predetermined stroke, resulting in the driven disk 572a (spindle 572) continuously rotating in one direction. That is, the link mechanism comprising the driving disk 550, connecting rod 560, and driven disk 572a converts the reciprocating rotational motion of the motor 10 into unidirectional rotational motion of the spindle 572. This link mechanism can also be interpreted as combining two crank mechanisms (specifically, a first crank mechanism serving as a first motion converter, comprising the driving disk 550 and connecting rod 560, and a second crank mechanism serving as a second motion converter, comprising the connecting rod 560 and driven disk 572a).

[0132] Furthermore, in the eighth embodiment, the motor 10 is driven by a command value determined based on a cam curve (solid line) shown in Fig. 43, which will be described later. This allows the output shaft 75 to rotate without applying an unnecessary load to the motor 10, thereby enabling the electric actuator 500 to consume less power.

[0133] Furthermore, the spindle unit 570 (more specifically, the bearing unit 574) of the eighth embodiment may incorporate a generator 80 ( FIG. 24 ). The power generated by the generator is converted to direct current by a converter, smoothed by a capacitor, and then input to the inverter. The inverter converts the direct current power into sine wave alternating current of the same quality as grid power and outputs it to the primary power source. According to the configuration of this embodiment, the generator generates power and supplies it to the primary power source 91 not only during regenerative operation but also during power running operation, thereby enabling more efficient use of electrical energy.

[0134] 24 is a block diagram showing a schematic configuration of a power supply system 590S (electric drive system 590) of an electric actuator 500 according to an eighth embodiment of the present invention. The power supply system 590S, together with the motor 10, constitutes the electric drive system 590.

[0135] The electric drive system 590 and the power supply system 590S of the eighth embodiment differ from the electric drive system 90 and the power supply system 90S of the first embodiment in that the electric drive system 590 and the power supply system 590S of the eighth embodiment include a generator 80 and an inverter device 97 that converts the electric power generated by the generator 80 into grid power (for example, three-phase AC) and supplies it to the primary power source. The inverter device 97 is connected to a control device 96 so as to be able to communicate with the control device 96, and operates under the control of the control device 96.

[0136] The inverter device 97 includes a converter 97a, an inverter 97b, and a capacitor 97c. The converter 97a includes, for example, a full-wave rectifier including a diode bridge circuit. A PWM converter may be provided on the input side of the converter 97a to convert the input current of the converter 97a into a sine wave. The inverter 97b is, for example, a PWM inverter that controls the output power by PWM control.

[0137] The power generated by the generator 80 is converted to DC by a converter 97a, smoothed by a capacitor 97c, and then input to an inverter 97b. A pair of positive and negative conductors constitutes a single DC bus 97d. The inverter 97b converts the DC power supplied from the DC bus 97d into sine wave AC of the same quality as the grid power and outputs it to the primary power source 91.

[0138] According to the configuration of this embodiment, the generator 80 generates electricity not only during regenerative operation but also during powering operation, and supplies power to the primary power source 91, thereby enabling more efficient use of electrical energy.

[0139] In this embodiment, the generator 80 is built into the bearing portion 574 of the spindle portion 570, but it may also be provided in the drive unit 500d. For example, the generator 80 may be provided between the motor 10 and the drive disk 550. Alternatively, the rotating shaft 11 of the motor 10 or the shaft portion 572b of the spindle 572 may be extended and connected to the input shaft of the generator 80, thereby supplying a portion of the power to the generator 80. Alternatively, a portion of the power may be branched off from the rotating shaft of the drive unit 500d or the spindle portion 570 and transmitted to the generator 80 by a winding transmission such as a belt or chain, or a gear mechanism.

[0140] Although the generator 80 in this embodiment is an AC generator, a DC generator may also be used. In this case, rectification of the power generated by the generator is not required, and therefore the converter 97a of the inverter device 97 is not required. For example, the output terminal of the DC generator is connected to the DC bus 97d without passing through the converter 97a.

[0141] A battery may be provided in the inverter device 97, and the battery may be connected in parallel with the capacitor 97c to the DC bus 97d.

[0142] Alternatively, a clutch may be provided between the generator 80 and the motor 10, and the timing at which the generator 80 absorbs power may be controlled by engaging and disengaging the clutch.

[0143] Furthermore, the DC bus 97d, the capacitor 97c, and the inverter 97b of the inverter device 97 may be common to the DC bus 95d, the capacitor 95c, and the power regeneration converter 95a of the servo amplifier 95, respectively.

[0144] Next, application examples of electric mobility, railway trains, vibration testing equipment, tire testing equipment, dynamic balancing combined testing equipment, uniformity testing equipment, balance measurement equipment, and collision simulation testing equipment equipped with electric actuators according to embodiments of the present invention will be described.

[0145] Ninth Embodiment This electric mobility vehicle includes an electric actuator, a power transmission device in which the output shaft of a motion converter is connected to an input shaft, a drive shaft connected to the output shaft of the power transmission device, and a wheel attached to the drive shaft. The electric actuator includes at least one electric motor, a capacitor, an inverter that drives the electric motor using power stored in the capacitor, a power regeneration converter that supplies battery power to the capacitor, and a motion converter having an input shaft to which rotational motion of the electric motor is transmitted and an output shaft that converts the rotational motion transmitted to the input shaft into unidirectional rotational motion and outputs the unidirectional rotational motion. The motion converter converts the forward / reverse rotational motion transmitted to the input shaft into unidirectional rotational motion and outputs the unidirectional rotational motion when the drive device drives the electric motor to rotate repeatedly forward and reverse. The drive device also regenerates regenerative power generated in the electric motor as the electric motor rotates repeatedly forward and reverse, and returns it to the capacitor. The power regeneration converter also supplies surplus regenerative power that is not charged in the capacitor to the battery. Specific configurations of an electric mobility according to one embodiment will be described below, but the electric mobility is not limited to these specific configurations.

[0146] FIG. 25 is a diagram showing a schematic configuration of a power system of an electric vehicle 1 equipped with an electric actuator 200 according to a fourth embodiment of the present invention as a prime mover. The electric vehicle 1 includes a power transmission 2 and left and right drive shafts 3a and 3b. The power transmission 2 includes a transmission, a final reduction gear, and a differential gear (not shown). A crankshaft 270 of the electric actuator 200 is connected to the input shaft of the power transmission 2. The drive shafts 3a and 3b are connected to the left and right output shafts of the power transmission 2, respectively. Wheels W are attached to the ends of each drive shaft 3a, 3b. Power output from the electric actuator 200 is transmitted to the drive shafts 3a, 3b via the transmission, final reduction gear, and differential gear of the power transmission 2, and rotates the wheels W attached to the ends of the drive shafts 3a, 3b.

[0147] The electric actuator according to the embodiment of the present invention can be used in place of various prime movers that output rotational motion (for example, engines, electric motors, hydraulic motors, air motors, steam turbines, etc.).

[0148] 25 is an example in which the electric actuator according to the embodiment of the present invention is applied to a four-wheeled electric vehicle, but the electric actuator according to the embodiment of the present invention can also be used in various types of vehicles such as two-wheeled vehicles, three-wheeled vehicles, or trucks, buses, tractors, etc. Furthermore, the electric actuator according to the embodiment of the present invention can also be used in hybrid vehicles, not limited to electric vehicles.

[0149] 26 is a block diagram showing a schematic configuration of a power supply system 790S (electric drive system 790) for an electric vehicle 1 according to a ninth embodiment of the present invention. The power supply system 790S constitutes the electric drive system 790 together with a plurality of electric actuators 200 (specifically, a plurality of motors 10) mounted on the electric vehicle 1.

[0150] The power supply system 790S shown in FIG. 26 includes four inverters 95b, four capacitors 95c, two changeover switches SW, a power regeneration converter 95a, and a control device 96.

[0151] When the control device 96 detects that the primary power source 91 has been connected to the external terminal Te during charging of the battery 295e mounted on the electric vehicle 1, it controls the contacts of each changeover switch SW so that the power regeneration converter 95a is electrically connected to the primary power source 91 (external power source) via the external terminal Te, and also controls the operation of the power regeneration converter 95a so that power is supplied from the primary power source 91 to the battery 295e.

[0152] Furthermore, when the electric vehicle 1 is running (when the drive shafts 3 a, 3 b shown in FIG. 25 are rotating), the control device 96 controls the contacts of each changeover switch SW so that the power regeneration converter 95 a is electrically connected to each inverter 95 b via each capacitor 95 c, and also controls the operation of the power regeneration converter 95 a and each inverter 95 b so that power is repeatedly exchanged between the battery 295 e and each motor 10, i.e., so that powering operation and regenerative operation are alternately repeated.

[0153] During powering operation, each inverter 95b converts DC power stored in the capacitor 95c and the battery 295e into AC power and supplies it to the motor 10, thereby driving the motor 10. During regenerative operation, each inverter 95b converts AC power regenerated from the motor 10 into DC power and stores some or all of that DC power in the capacitor 95c. Each inverter 95b charges the battery 295e by supplying surplus regenerated power that is not stored in the capacitor 95c to the battery 295e via the selector switch SW and the power regeneration converter 95a. That is, each inverter 95b supplies surplus power overflowing from the capacitor 95c, among the regenerated power regenerated to the capacitor 95c, to the primary power source 91. In other words, each inverter 95b supplies surplus power corresponding to the power consumed by the acceleration of the motor 10 and the regenerated power, to the battery 295e. In other words, when the motor 10 repeatedly rotates forward and backward, each inverter 95b outputs to the battery 295e the surplus power regenerated from the motor 10 that is not consumed by accelerating the motor 10.

[0154] Here, for example, assume that two of the four motors 10 shown in FIG. 26 are designated as first motors, and the remaining two motors 10 are designated as second motors. That is, the two motors 10 included in the first motor operate identically in the powering section (e.g., section A or section C shown in FIG. 7A ) and the regenerating section (e.g., section B or section D shown in FIG. 7A ). Similarly, the two motors 10 included in the second motor operate identically in the powering section and the regenerating section. Note that the two capacitors 95c connected to the first motor and the two capacitors 95c connected to the second motor are connected in parallel, and therefore the four capacitors 95c can be considered as one capacitor 95c. Hereinafter, when the four capacitors 95c are not distinguished, they will be described as one capacitor 95c. In addition, the first motor and the second motor are driven so that the powering section of the first motor becomes the regenerative section of the second motor, and the powering section of the second motor becomes the regenerative section of the first motor.

[0155] When the electric vehicle 1 is started (when it starts to travel), first, power is supplied from the battery 295e to the first motor via the power regeneration converter 95a, and the first motor accelerates when it rotates in the forward direction (power running when it starts to travel). Then, the first motor decelerates when it rotates in the forward direction, and power is regenerated from the first motor to the capacitor 95c (first motor regeneration section). During this first motor regeneration section, power is simultaneously supplied to the second motor via the capacitor 95c, and the second motor accelerates when it rotates in the forward direction (second motor power running section). Next, the second motor decelerates when it rotates in the forward direction, and power is regenerated from the second motor to the capacitor 95c (second motor regeneration section). During this second motor regeneration section, power is simultaneously supplied to the first motor via the capacitor 95c, and the first motor accelerates when it rotates in the reverse direction (first motor power running section). Next, the first motor decelerates when it rotates in the reverse direction, and power is regenerated from the first motor to the capacitor 95c (first motor regeneration section). During this first motor regeneration section, power is simultaneously supplied to the second motor via the capacitor 95c, and the second motor accelerates when it rotates in the reverse direction (second motor powering section). Then, the second motor decelerates when it rotates in the reverse direction, and power is regenerated from the second motor to the capacitor 95c (second motor regeneration section). During this second motor regeneration section, power is simultaneously supplied to the first motor via the capacitor 95c, and the first motor accelerates when it rotates in the forward direction (first motor powering section). Thereafter, similar acceleration and deceleration are repeated during forward and reverse rotation of the first and second motors. That is, after power is supplied from the battery 295e to the first motor when the electric vehicle 1 is started, power is repeatedly exchanged between the first motor and the second motor.

[0156] If the total power of the power output from the motor 10 during regeneration and the power stored in the capacitor 95c is less than the power required to drive the motor 10 during power running, the shortage of power is supplied from the battery 295e via the power regeneration converter 95a to the motor 10 during power running. If the total power of the power output from the motor 10 during regeneration and the power stored in the capacitor 95c is greater than the power required to drive the motor 10 during power running, the surplus power is supplied from the capacitor 95c to the battery 295e via the power regeneration converter 95a.

[0157] In this way, the electric vehicle 1 shown in FIG. 26 is configured so that power is exchanged between the four motors 10, and therefore the power supplied from the battery 295e to the four motors 10 can be reduced, thereby improving the system efficiency of the electric vehicle 1.

[0158] Furthermore, the number of motors constituting the first motor and the second motor is not limited to two. For example, the electric actuator 201 shown in FIG. 18 and the electric actuator 400 shown in FIG. 21 are examples in which the first motor and the second motor are each constituted by one motor. Furthermore, the power unit PU shown in FIG. 46 and the power unit PU shown in FIG. 48 are examples in which the first motor is constituted by two motors and the second motor is constituted by one motor. As the number of motors 10 increases, fluctuations in the power stored in the capacitor 95c can be suppressed, thereby further improving system efficiency.

[0159] Furthermore, the electric actuator according to the embodiment of the present invention can be used not only for automobiles but also as a prime mover for railway vehicles.

[0160] Tenth Embodiment The tenth embodiment described next is an example in which the present invention is applied to a railway system.

[0161] Figure 27 is a diagram showing a schematic configuration of a drive mechanism of a railway vehicle 600 according to a tenth embodiment of the present invention. The railway vehicle 600 includes a plurality of (three in the example shown in Figure 27) bogies 601. The bogies 601 are moving bogies that include, as a drive device, the electric actuator 200 according to the fourth embodiment of the present invention.

[0162] The bogie 601 includes two electric actuators 200, two pairs of axles 603 (axles 603a, 603b), bearings 602, axle boxes (not shown), axle box support devices (not shown), and wheels 604. One end of the axles 603a and 603b is connected to both ends of the crankshaft 270 of the electric actuator 200. The wheels 604 are attached to the other ends of the axles 603a and 603b.

[0163] Each bearing 602 is attached to an axle box, and each axle box is attached to a bogie frame 605 via an axle box support device. The bearings 602 and axle boxes are shock-absorbingly supported by the axle box support device relative to the bogie frame 605 (frame). Each axle 603 a and 603 b is rotatably supported by each bearing 602.

[0164] 28 is a block diagram showing a schematic configuration of a power supply system 690S (electric drive system 690) of a railway vehicle 600 according to a tenth embodiment of the present invention. The power supply system 690S constitutes the electric drive system 690 together with a plurality of electric actuators 200 (specifically, a plurality of motors 10) mounted on the railway vehicle 600.

[0165] The railway vehicle 600 is a powered vehicle that collects current by an overhead line current collection system, and includes a pantograph 692c that contacts an overhead line 691b, which is a contact wire (contact wire), as a current collector. The overhead line 691b is supplied with system power (e.g., three-phase AC) from a substation 691a.

[0166] Of the electric drive system 690 (power supply system 690S), the mobile body drive system 690M (mobile body power supply system 690MS) mounted on the railway vehicle 600 is composed of one or more mobile body drive units 690MU (mobile body power supply system 690MSU) unitized for each corresponding bogie 601. Note that the mobile body drive units 690MU (mobile body power supply system 690MSU) may be configured not for each bogie 601, but for each railway vehicle 600, or for each train consisting of multiple railway vehicles 600 coupled together.

[0167] The electric drive system 690 according to the tenth embodiment of the present invention provides the same effects as the electric drive system 290 according to the second embodiment of the present invention. That is, because regenerative power is efficiently used to drive the motor 10, it is possible to drive the railway vehicle 600 (electric actuator 200) with low power consumption.

[0168] In this embodiment, an overhead line current collection method is adopted in which the pantograph 692c is used as a current collector, but other types of current collectors (e.g., a bugle, a trolley pole, etc.) or other types of current collection methods (e.g., a third rail method in which current is collected by contacting a collector shoe with a power supply rail (third rail)) may also be used.

[0169] The railway vehicle 600 of this embodiment is a bogie-type vehicle that uses a bogie 601 as a running device, and the mobile body drive unit 690MU is mounted on the bogie 601, but the present invention is not limited to this configuration. For example, the running device and the mobile body drive unit 690MU may be directly provided on the car body.

[0170] In this embodiment, the mobile body drive unit 690MU (specifically, the servo amplifier 695) of each bogie 601 is equipped with a battery 295e, but the battery 295e may be shared by the mobile body drive units 690MU of multiple bogies 601. In this case, for example, the battery 295e may be provided in only one (or some) of the servo amplifiers 695 of the multiple bogies 601, and the DC buses 95d of the multiple bogies 601 may be connected to the battery 295e. Alternatively, the battery 295e may be arranged outside the servo amplifier 695 (for example, on the car body) and connected to the DC buses 95d of the multiple bogies 601.

[0171] In this embodiment, a configuration is adopted in which the axles 603a, 603b are directly connected to both ends of the crankshaft 270 of the electric actuator 200, but the present invention is not limited to this configuration. For example, a configuration may be adopted in which the electric actuator 200 and the undivided axle 603 are connected via a power transmission device such as a gear device.

[0172] In this embodiment, an axle box support system using an axle box and an axle box support device is employed, but the present invention is not limited to this configuration.

[0173] Eleventh Embodiment A vibration testing apparatus according to one embodiment includes an electric actuator and a controller that controls the electric actuator. The electric actuator includes a vibration table to which an object to be vibrated is attached, an electric motor, and a drive device that drives the electric motor using power stored in a capacitor, and vibrates the vibration table in a predetermined direction. The controller controls the electric actuator to vibrate the vibration table at a predetermined amplitude and frequency. The vibration testing apparatus then regenerates, into the capacitor, regenerative power generated in the electric motor as a result of the vibration table being vibrated at the predetermined amplitude and frequency, and supplies surplus power of the regenerative power to a power supply. Specific configurations of the vibration testing apparatus according to one embodiment are described below, but the present invention is not limited to these specific configurations.

[0174] 29 is a plan view of a vibration testing apparatus (vibration apparatus) 1000 according to an eleventh embodiment of the present invention. The vibration testing apparatus 1000 of this embodiment is a power-saving motor system equipped with multiple electric motors as prime movers and capable of operating with less power consumption than conventional systems, and a power-saving testing system equipped with this power-saving motor system. The vibration testing apparatus 1000 is configured so that a workpiece to be subjected to a vibration test is fixed on a vibration table 3, and first, second, and third actuators 4, 5, and 6 are used to vibrate the vibration table 3 and the workpiece placed thereon in three orthogonal axial directions. The workpiece is the object to be vibrated, and the vibration table 3 is an example of a vibration table to which the object to be vibrated is attached. In the following description, the direction in which the first actuator 4 vibrates the vibration table 3 (the up-down direction in FIG. 1) is defined as the X-axis direction, the direction in which the second actuator 5 vibrates the vibration table 3 (the left-right direction in FIG. 1) is defined as the Y-axis direction, and the direction in which the third actuator 6 vibrates the vibration table 3, i.e., the vertical direction (the direction perpendicular to the paper surface in FIG. 1), is defined as the Z-axis direction. The X-axis direction and the Y-axis direction are horizontal directions that are perpendicular to each other.

[0175] The first actuator 4, the second actuator 5, and the third actuator 6 are electric actuators that vibrate the vibration table 3 in a predetermined direction, and each includes a servo motor. The servo motor is, for example, an ultra-low inertia, high-output AC servo motor that is an electric motor that can switch between forward and reverse rotation. The use of such an ultra-low inertia, high-output servo motor enables repeated reciprocating drive (forward / reverse reversal drive) at a high frequency of 100 Hz or more.

[0176] The first, second and third actuators 4, 5 and 6 each have a configuration in which a motor, a power transmission member and the like are attached to a base plate 7. This base plate 7 is fixed onto a device base 8 by bolts (not shown).

[0177] Twelfth Embodiment Next, an example in which the present invention is applied to a tire testing apparatus will be described. The tire testing apparatus according to the twelfth embodiment of the present invention described below is a testing apparatus capable of conducting tire wear tests, durability tests, running stability tests, and the like. The tire testing apparatus according to one embodiment includes an electric actuator and a controller that controls the electric actuator. The electric actuator includes an electric motor having a rotating shaft connected to the center axis of the tire, and a drive unit that drives the electric motor using power stored in a capacitor. The controller controls the electric actuator to cause the electric motor to generate a fluctuating torque. The tire testing apparatus regenerates regenerative power generated in the electric motor as the rotational speed of the tire decelerates in accordance with the fluctuating torque of the electric motor, and supplies surplus power of the regenerative power to a power source. Specific configurations of the tire testing apparatus according to one embodiment will be described below, but the tire testing apparatus is not limited to these specific configurations.

[0178] 30 and 31 are perspective views of a tire testing apparatus 2000 according to an eleventh embodiment of the present invention, as seen from different directions. The tire testing apparatus 2000 of this embodiment includes a rotating drum 2010 having a simulated road surface formed on its outer circumferential surface, an alignment adjustment mechanism 2160 that rotatably holds the tire T in a state in which the tire T is in contact with the simulated road surface in a predetermined attitude, a torque generating device 130 (slip ratio control device) that generates torque to be applied to the tire T, and an inverter motor 2080 that rotationally drives the casings of the rotating drum 2010 and the torque generating device 130.

[0179] The rotating drum 2010 is rotatably supported by a pair of bearings 2011a. A pulley 2012a is attached to the output shaft of the inverter motor 2080, and a pulley 2012b is attached to one of the shafts of the rotating drum 2010. The pulleys 2012a and 2012b are connected by a drive belt 2015 (e.g., a toothed belt). A pulley 2012c is attached to the other shaft of the rotating drum 2010 via an intermediate shaft 2013. The intermediate shaft 2013 is rotatably supported by a bearing 2011b near one end where the pulley is attached. The pulley 2012c is connected to a pulley 2012d by a drive belt 2016. The pulley 2012d is coaxially fixed to the pulley 2012e and rotatably supported together with the pulley 2012e by a bearing 2011c ( FIG. 31 ). The pulley 2012e is connected to a shaft 131a of a casing 131 (described later) of the torque generating device 130 by a drive belt 2017.

[0180] Figure 32 is a diagram showing the internal structure of the torque generator 130. The torque generator 130 includes a casing 131, a motor 10 fixed inside the casing 131, and a reducer 133. Note that in this embodiment, a motor 10 having the same configuration as that in the first embodiment is used. Cylindrical shaft portions 131a and 131b are formed at both axial ends of the casing 131. The casing 131 is rotatably supported by bearing portions 2020 and 2030 at the shaft portions 131a and 131b. A pulley 2012f is attached to the outer periphery of the shaft portion 131a at one end (the right end in Figure 32).

[0181] The reducer 133 has an input shaft 133a and an output shaft 133b, and reduces the rotational motion input to the input shaft 133a and outputs it to the output shaft 133b. The input shaft 133a of the reducer 133 is connected to the drive shaft 150a of the motor 10 by a coupling 134. A connecting shaft 135 is connected to the output shaft 133b of the reducer 133. The reducer 133 may be optionally provided in the torque generator 130. The connecting shaft 135 may be directly connected to the drive shaft 150a of the motor 10 without providing the reducer 133 in the torque generator 130.

[0182] The connecting shaft 135 is passed through the hollow portion of the cylindrical shaft portion 131a of the casing 131 and is rotatably supported by a pair of bearings 136 provided on the inner periphery of the shaft portion 131a. The tip of the connecting shaft 135 protrudes from the tip of the shaft portion 131a. The connecting shaft 135 protruding from the shaft portion 131a is connected to the spindle of the alignment adjustment mechanism 2160 via a constant velocity joint 2014 (FIG. 30). A wheel with a tire T mounted thereon is attached to the spindle of the alignment adjustment mechanism 2160.

[0183] As a result, when inverter motor 2080 is driven, rotating drum 2010 rotates, and also rotates casing 131 of torque generator 130 connected to inverter motor 2080 via rotating drum 2010. Furthermore, when torque generator 130 is not operating, rotating drum 2010 and tire T rotate in opposite directions so that the peripheral speeds at the contact points are the same. Furthermore, by operating torque generator 130, dynamic or static driving force and braking force can be applied to tire T.

[0184] In the present embodiment, the power output from the inverter motor 2080 is transmitted again to the rotating drum 2010 via the rotating drum 2010, intermediate shaft 2013, torque generator 130, constant velocity joint 2014, the spindle of the alignment adjustment mechanism 2160, and tire T. In other words, the power transmission path made up of the rotating drum 2010, intermediate shaft 2013, torque generator 130, constant velocity joint 2014, the spindle of the alignment adjustment mechanism 2160, and tire T constitutes a power circulation system. Therefore, the power of the inverter motor 2080 is used efficiently, enabling operation with low power consumption.

[0185] The alignment adjustment mechanism 2160 of this embodiment is a mechanism that rotatably supports a tire T, which is a test specimen, mounted on a wheel, presses the tread portion of the tire T against the simulated road surface of the rotating drum 2010, and adjusts the orientation of the tire T with respect to the simulated road surface and the tire load (ground contact pressure) to set states. The alignment adjustment mechanism 2160 includes a tire load adjustment unit 2161 that adjusts the tire load by moving the position of the rotation axis of the tire T in the radial direction of the rotating drum 2010, a slip angle adjustment unit 2162 that adjusts the slip angle of the tire T with respect to the simulated road surface by tilting the rotation axis of the tire T about a line perpendicular to the simulated road surface, a camber angle adjustment unit 2163 that adjusts the camber angle by tilting the rotation axis of the tire T with respect to the rotation axis of the rotating drum 2010, and a traverse device 2164 that moves the tire T in the direction of the rotation axis. The tire load adjustment unit 2161, the slip angle adjustment unit 2162, the camber angle adjustment unit 2163, and the traverse device 2164 are respectively equipped with servo motors M1, M2, M3, and M4. The servo motors M1, M2, M3, and M4 are, for example, AC servo motors.

[0186] FIG. 33 is a block diagram showing a schematic configuration of a power supply system 2800S (electric drive system 2800) according to the second embodiment of the present invention, which supplies power to the motor 10 and the inverter motor 2080.

[0187] The power supply system 2800S of this embodiment differs from the power supply system 90S of the first embodiment in that it includes a power supply system 2860 (reactor 2870, driver 2880) that supplies power to the inverter motor 2080 branched from the downstream side of the electromagnetic switch 2830, and power supply systems 2891 (reactor R1, servo amplifier A1), 2892 (reactor R2, servo amplifier A2), 2893 (reactor R3, servo amplifier A3), and 2894 (reactor R4, servo amplifier A4) that supply power to the servo motors M1, M2, M3, and M4 of the alignment adjustment mechanism 2160, respectively. The driver 2880 is a device that generates drive power for the inverter motor 2080 and includes an inverter circuit (not shown). The driver 2880 and the servo amplifiers A1 to A4 are each communicatively connected to a control unit C2 and operate under the control of the control unit C2. The servo amplifiers A1, A2, A3, and A4 have the same configuration as the servo amplifier 2850.

[0188] In a test using the tire testing apparatus 2000 of this embodiment, a rotational motion is applied to the tire T that is a combination of the rotation speed output by the inverter motor 2080 and the torque generated by the torque generating device 130 (specifically, the motor 10). In one example of a test using the tire testing apparatus 2000, the inverter motor 2080 is controlled to output a constant rotation speed, and the motor 10 is controlled to output a fluctuating torque (for example, a random vibration torque). As the motor 10 is repeatedly accelerated and decelerated, the supply of driving power from the servo amplifier 2850 to the motor 10 and the supply of regenerative power from the motor 10 to the servo amplifier 2850 are repeated.

[0189] A portion or all of the regenerative power generated when the motor 10 decelerates is temporarily stored in the capacitor 2853 and then used the next time the motor 10 accelerates. Note that surplus regenerative power that is not stored in the capacitor 2853 is supplied to the power supply systems 2860, 2891, 2892, 2893, and 2894 via the power supply regenerative converter 2851 and the reactor 2840, and is used to drive the inverter motor 2080 and the servo motors M1, M2, M3, and M4. Therefore, most of the regenerative power generated by the motor 10 is reused to drive the motors 10, M1 to M4, and the inverter motor 2080, and the power consumption of the primary power supply 2810 used to drive the motor 10 is slightly reduced. In addition, the regenerative power generated by the inverter motor 2080 and the servo motors M1, M2, M3, and M4 is also reused to drive other motors (i.e., motor 10, servo motors M1, M2, M3, and M4, and the inverter motor 2080), further reducing the power consumption of the primary power source 2810.

[0190] By setting the tire T in the tire testing apparatus 2000 having the above-described configuration and driving the inverter motor 2080 for rotational drive, the tire T and the rotating drum 2010 rotate at the same peripheral speed. In this state, by driving the motor 10 of the torque generating device 130 to apply a driving force or a braking force to the tire T, it becomes possible to perform tire wear tests, durability tests, running stability tests, and the like that simulate actual running conditions.

[0191] In this embodiment, the inverter motor 2080 is used to rotate the tire T and the rotating drum 2010 at the same peripheral speed, but the electric actuator 100 according to the first embodiment, which includes the motor 10 and the drive unit 100d, may be used instead of the driver 2880 and the inverter motor 2080 in FIG. 33 . That is, instead of directly attaching the pulley 2012a to the output shaft of the motor 10, the drive unit 100d, which converts the reciprocating rotation of the motor 10 into unidirectional rotation, may be provided between the motor 10 and the pulley 2012a. This makes it possible to use regenerative energy to rotate the tire T and the rotating drum 2010 at the same peripheral speed.

[0192] Thirteenth Embodiment A uniformity test apparatus and a dynamic balancing combined test apparatus according to one embodiment will be described. The uniformity test apparatus includes a rotating drum that contacts a tire, an electric actuator including an electric motor and a drive device that drives the electric motor using power stored in a capacitor, a motion converter that converts forward and reverse rotation output by the electric motor into unidirectional rotational motion and transmits the unidirectional rotational motion to the rotating drum, and a controller that controls the electric actuator so that the rotating drum rotates at a predetermined speed by rotating the electric motor forward and reverse. Regenerative power generated in the electric motor as the rotating drum rotates at the predetermined speed is regenerated and sent to the capacitor, and surplus power from the regenerative power is supplied to a power source. The dynamic balancing hybrid testing apparatus also includes a spindle on which a tire is mounted, an electric actuator including an electric motor and a drive unit that drives the electric motor using power stored in a capacitor, a motion converter that converts forward and reverse rotation output by the electric motor into unidirectional rotational motion, a transmission mechanism that transmits the unidirectional rotational motion output by the motion converter to the spindle, and a controller that controls the electric actuator so that the spindle rotates at a predetermined speed by rotating the electric motor forward and backward. Regenerative power generated in the electric motor as the spindle rotates at the predetermined speed is regenerated and sent to the capacitor, and surplus power from the regenerated power is supplied to a power source. The hybrid testing apparatus according to a thirteenth embodiment of the present invention, described below, is capable of performing tire uniformity tests and dynamic balancing tests. Figure 34 is a side view showing the basic configuration of a hybrid testing apparatus 3000 for uniformity and dynamic balancing according to an embodiment of the present invention (hereinafter referred to as the hybrid testing apparatus 3000). FIG. 35 is a schematic diagram showing a method for rotating the spindle 3120 of the hybrid testing apparatus 3000. In FIG.

[0193] 34 , the composite testing apparatus 3000 is configured to hold the tire T by sandwiching it vertically between a lower rim 3010 and an upper rim 3020. More specifically, the composite testing apparatus 3000 sandwiches and holds the tire T between the lower rim 3010 and the upper rim 3020 by inserting and fixing a lock shaft 3300, to the upper end of which the upper rim 3020 is fixed, into the spindle 3120.

[0194] The uniformity test uses a rotating drum 3030 provided on the side of the spindle 3120. The rotating drum 3030 is mounted on a movable housing 3032 that is slidable on rails 3031 that extend in a direction approaching / moving away from the tire T, and is moved in the direction approaching / moving away from the tire T by a rack and pinion mechanism 3035 (pinion 3036 and rack 3038) driven by a motor (not shown). The rotating drum 3030 can be rotated at any rotation speed by an electric actuator (not shown, hereinafter referred to as electric actuator 100a). The configuration of the electric actuator 100a is the same as the electric actuator 100 described above in the first embodiment.

[0195] When conducting a uniformity test, the rotating drum 3030 is brought into contact with the tire T by the rack and pinion mechanism 3035, and the rotating drum 3030 is pressed against the tire T with a force of several hundred kgf or more. Next, the rotating drum 3030 is rotated in this state (thus, the tire T in contact with the rotating drum 3030 also rotates along with the rotating drum 3030), and the variation in force generated in the rotating tire due to the fluctuation in load at this time is measured by a triaxial piezoelectric element installed on the side of the spindle housing 3110.

[0196] In this embodiment, the rotating drum 3030 is rotated using the electric actuator 100a, which allows the rotating drum 3030 to rotate while utilizing regenerative energy, thereby enabling a uniformity test to be performed.

[0197] On the other hand, the dynamic balancing test involves rotating the tire T together with the spindle 3120 while the rotating drum 3030 is spaced apart from the tire T, and measuring the eccentricity of the tire from the excitation force generated by the imbalance of the tire T.

[0198] A pulley 3140 is attached to the lower end of the spindle 3120 for rotating and driving the spindle 3120 during a dynamic balancing test. In addition, an electric actuator 100b that can move horizontally toward and away from the spindle 3120 by a rack and pinion mechanism (not shown) is installed on a base 3050 to which the spindle 3120 is fixed, and this electric actuator 100b rotates the spindle 3120. The configuration of the electric actuator 100b is the same as the electric actuator 100 described above in the first embodiment. This makes it possible to rotate the spindle 3120 using regenerative energy and perform a dynamic balancing test.

[0199] A drive pulley 3144 is attached to the output rotation shaft of the electric actuator 100b at the same height as the pulley 3140 of the spindle 3120. Also, as shown in Figure 35, a pair of driven pulleys 3143 are rotatably installed at the same height as the drive pulley 3144 and the pulley 3140 of the spindle 3120. The driven pulley 3143 moves forward and backward together with the electric actuator 100b (drive pulley 3144) by the rack and pinion mechanism (not shown). An endless belt 3142 is stretched between the drive pulley 3144 and the driven pulley 3143, and the endless belt 3142 can be advanced and advanced at a predetermined speed by the electric actuator 100b.

[0200] By driving the electric actuator 100b in a state where the endless belt 3142 is in contact with the pulley 3140 by the rack and pinion mechanism (the state shown by the solid line in FIG. 35 ), the pulley 3140 rotates, and the spindle 3120 rotates while holding the tire T between the lower rim 3010 and the upper rim 3020. At this time, the excitation force is measured by a triaxial piezoelectric element installed on the side of the spindle housing 3110.

[0201] In this embodiment, by using the electric actuator 100b, the spindle 3120 can be rotated while utilizing regenerative energy, thereby enabling a dynamic balancing test to be performed.

[0202] That is, the composite testing device 3000 is provided with two electric actuators 100a and 100b, which are the same as the electric actuator 100 of the first embodiment, and the electric actuator 100a is used to rotate the rotating drum 3030, and the electric actuator 100b is used to rotate the spindle 3120. This makes it possible to perform both the uniformity test and the dynamic balancing test while utilizing regenerative energy.

[0203] Fourteenth Embodiment A balance measurement device according to one embodiment includes an electric actuator including an electric motor and a drive unit that drives the electric motor using power stored in a capacitor; a motion converter that converts forward and reverse rotation output by the electric motor into unidirectional rotational motion; a transmission mechanism that transmits the unidirectional rotational motion output by the motion converter to a test piece; and a controller that controls the electric actuator so that the test piece rotates at a predetermined speed by rotating the electric motor forward and backward. Regenerative power generated in the electric motor as the test piece rotates at the predetermined speed is regenerated and sent to the capacitor, and surplus power from the regenerated power is supplied to a power source. Specific configurations of the balance measurement device according to one embodiment are described below, but the present invention is not limited to these specific configurations.

[0204] A balance measurement device 4000 according to a fourteenth embodiment of the present invention, which will be described below, is a testing device capable of measuring the balance of a rotating body. FIGS. 36 and 37 are a front view and a side view, respectively, of the balance measurement device 4000 according to this embodiment of the present invention. In the following description, the up-down direction in FIG. 36 is defined as the Y-axis direction, and the direction perpendicular to both the up-down direction and the direction of the rotational axis of the rotating body is defined as the X-axis direction. The rotating body 4100 of this embodiment is, for example, a crankshaft, and the balance measurement device 4000 is, for example, a device for measuring the balance of a crankshaft.

[0205] The balance measurement device 4000 has a frame made up of a base 4013, a plurality of springs 4014 extending vertically upward from the base 4013, and a table 4015 supported by the springs 4014. Drive shaft bearings 4012a and 4012b are attached to the underside of the table 4015. The drive shaft 4005 is rotatably supported by the drive shaft bearings 4012a and 4012b. In addition, as shown in FIG. 37 , a first side wall 4013a and a second side wall 4013b, which can be considered to be substantially rigid bodies, extend vertically upward from both ends of the base 4013 in the X-axis direction.

[0206] The electric actuator 100 according to the first embodiment is attached to the base 4013. A pulley 4003 is attached to the drive shaft of the electric actuator 100. Meanwhile, a first pulley 4006 is attached to one end of a drive shaft 4005, and a first endless belt 4004 is stretched between this first pulley 4006 and the pulley 4003 attached to the drive shaft of the electric actuator 100. By driving the electric actuator 100, the drive shaft 4005 can be rotated via the first endless belt 4004.

[0207] Furthermore, a first table sidewall 4017a and a second table sidewall 4017b are fixed vertically above the top surface of the table 4015 and are parallel to each other. The first table sidewall 4017a and the second table sidewall 4017b are rigid bodies having extremely high rigidity compared to the spring constant of the spring 4014. Driven shaft bearings 4016a and 4016c are fixed to the first table sidewall 4017a, and driven shaft bearings 4016b and 4016d are fixed to the second table sidewall 4017b. Note that only the driven shaft bearings 4016a and 4016b are shown in FIG. 36, and the driven shaft bearings 4016c and 4016d are located on the far side of the driven shaft bearings 4016a and 4016b, respectively, in FIG. The driven shaft bearings 4016a, 4016b, 4016c, and 4016d rotatably support the driven shafts 4010a, 4010b, 4010c, and 4010d (only 4010a and 4010b are shown in Figure 36), respectively.

[0208] Pulleys 4009a, 4009b, 4009c, and 4009d are attached to one ends of driven shafts 4010a, 4010b, 4010c, and 4010d, respectively. Second pulleys 4007a and 4007b are attached to one end of drive shaft 4005 adjacent to first pulley 4006 and to the other end of drive shaft 4005. Second endless belts 4008a and 4008b are passed between second pulley 4007a, pulley 4009a attached to driven shaft 4010a, pulley 4009c attached to driven shaft 4010c, second pulley 4007b, pulley 4009b attached to driven shaft 4010b, and pulley 4009d attached to driven shaft 4010d, respectively. Therefore, when the drive shaft 4005 rotates, its power is transmitted to the driven shafts 4010a and 4010c via the second endless belt 4008a, causing the driven shafts 4010a and 4010c to rotate. Furthermore, the power from the drive shaft 4005 is also transmitted to the driven shafts 4010b and 4010d via the second endless belt 4008b, causing the driven shafts 4010b and 4010d to also rotate.

[0209] Rollers 4011a, 4011b, 4011c, and 4011d are attached to the other ends of driven shafts 4010a, 4010b, 4010c, and 4010d, respectively. One end 4110a of the rotation shaft of rotating body 4100 is placed on rollers 4011a and 4011c, and the other end 4110b of the rotation shaft of rotating body 4100 is placed on rollers 4011b and 4011d. Rotating body 4100 rotates in response to the rotation of rollers 4011a, 4011b, 4011c, and 4011d. In other words, by driving electric actuator 100, rotating body 4100 can be rotated using regenerative energy.

[0210] A key groove 4102 is formed at the other end 4110b of the rotor 4100. The balance measuring device 4000 further includes a sensor S for detecting the key groove 4102.

[0211] 36 and 37 , vibration pickups VDL and VDR are attached between the first side wall 4013a of the base 4013 and the table 4015. The rotating body 4100, which is a crankshaft having a dynamic imbalance, vibrates when it rotates. In the balance measuring device of this embodiment, the vibration of the rotating body 4100 (crankshaft) is transmitted to the table 4015 via rollers 4011a, 4011b, 4011c, 4011d, first and second table side walls 4017a, 4017b, etc. The vibration pickups VDL and VDR detect the vibration transmitted from the rotating rotating body 4100 (crankshaft) to the table 4015. In other words, the vibration pickups VDL and VDR detect the fluctuations in the load that the rotating rotor 4100 (crankshaft) applies to the rollers 4011a, 4011b, 4011c, and 4011d.

[0212] The vibration pickups VDL and VDR are acceleration sensors capable of measuring acceleration of two components (X-axis direction and Y-axis direction) perpendicular to the rotation axis of the rotating body 4100. The vibration pickup VDL is attached on the same XY plane as the first table side wall 4017a, and the vibration pickup VDR is attached on the same XY plane as the second table side wall 4017b.

[0213] Furthermore, piezoelectric actuators VL and VR are attached between the second side wall 4013b of the base 4013 and the table 4015. The piezoelectric actuator VL is attached on the same XY plane as the first table side wall 4017a, and the piezoelectric actuator VR is attached on the same XY plane as the second table side wall 4017b. A piezoelectric actuator is a member that can expand and contract depending on the magnitude of the voltage applied to it, thereby displacing an object that it comes into contact with. Therefore, by controlling the signals input to the piezoelectric actuators VL and VR, it is possible to freely vibrate the table 4015.

[0214] Fifteenth Embodiment A crash simulation test apparatus according to one embodiment includes a mounting portion to which a test specimen is attached, an electric actuator including an electric motor and a drive device that drives the electric motor using power stored in a capacitor, a motion converter that converts forward and reverse rotation output from the electric motor into unidirectional rotational motion, a transmission mechanism that converts the unidirectional rotational motion output from the motion converter into linear motion and transmits the linear motion to the mounting portion, and a controller that controls the electric actuator to rotate the electric motor forward and reverse to impart a desired acceleration to the mounting portion. Regenerative power generated in the electric motor by imparting the desired acceleration to the mounting portion is regenerated and sent to the capacitor, and surplus power of the regenerated power is supplied to a power source. Specific configurations of the crash simulation test apparatus according to one embodiment are described below, but the present invention is not limited to these specific configurations.

[0215] 38 is a perspective view of a collision simulation test apparatus 5000 according to a fifteenth embodiment of the present invention. The collision simulation test apparatus 5000 is an apparatus that reproduces the impact that is applied to automobiles, occupants, and equipment of automobiles, etc., when automobiles, etc. (including railway vehicles, aircraft, and ships) collide. The collision simulation test apparatus 5000 of this embodiment can also be used as an impact test apparatus that applies a strong shock wave to products and parts to evaluate their durability and reliability against impact.

[0216] The crash simulation test device 5000 includes a table 5240 that resembles the frame of an automobile vehicle. A test object, such as a seat carrying a passenger dummy or a high-voltage battery for an electric vehicle, is attached to the table 5240. When the table 5240 is driven at a set acceleration (e.g., acceleration corresponding to the impact applied to the vehicle frame during a collision), an impact similar to that of an actual collision is applied to the test object attached to the table 5240. The safety of the occupants is evaluated based on the damage sustained by the test object at this time (or damage predicted from the measurement results of an acceleration sensor or the like attached to the test object).

[0217] The collision simulation test apparatus 5000 of this embodiment is configured to be able to drive the table 5240 in only one horizontal direction. As shown by the coordinate axes in FIG. 38 , the movable direction of the table 5240 is defined as the X-axis direction, the horizontal direction perpendicular to the X-axis direction as the Y-axis direction, and the vertical direction as the Z-axis direction. Furthermore, with respect to the traveling direction of the vehicle being simulated, the positive X-axis direction is referred to as the forward direction, the negative X-axis direction as the backward direction, the negative Y-axis direction as the rightward direction, and the positive Y-axis direction as the leftward direction. Furthermore, the X-axis direction in which the table 5240 is driven is referred to as the "driving direction." Note that, in a collision simulation test, a large acceleration is applied to the table 5240 in the direction opposite to the traveling direction of the vehicle (i.e., backward).

[0218] The collision simulation test device 5000 includes a test section 5200 equipped with a table 5240, a front drive section 5300 and a rear drive section 5400 that drive the table 5240, four belt mechanisms 5100 (belt mechanisms 5100a, 5100b, 5100c, 5100d) that convert the rotational motion generated by each drive section 5300, 5400 into translational motion in the X-axis direction and transmit the translational motion to the table 5240, and a control system (not shown).

[0219] The test section 5200 is disposed at the center of the collision simulation test device 5000 in the X-axis direction, and the front drive section 5300 and the rear drive section 5400 are disposed adjacent to the front and rear of the test section 5200, respectively.

[0220] Fig. 39 is a perspective view showing the structures of the testing unit 5200 and the belt mechanism 5100. For ease of explanation, Fig. 39 omits illustration of a table 5240 and a base block 5210 (described later), which are components of the testing unit 5200.

[0221] In addition to the table 5240, the testing section 5200 includes a base block 5210 (FIG. 35), a frame 5220 attached to the base block 5210, and a pair of linear guideways 5230 (hereinafter abbreviated as "linear guides 5230") attached to the frame 5220. The pair of linear guides 5230 support the table 5240 so that it can move only in the X-axis direction (drive direction).

[0222] 39, the frame 5220 has a pair of left and right half frames (a right frame 5220R and a left frame 5220L) connected by a plurality of connecting bars 5220C extending in the Y-axis direction. Since the right frame 5220R and the left frame 5220L have the same structure (strictly speaking, they are mirror images), only the left frame 5220L will be described in detail.

[0223] The left frame 5220L has an attachment portion 5221 and a rail support portion 5222 that each extend in the X-axis direction, and three connecting portions 5223 (5223a, 5223b, 5223c) that extend in the Z-axis direction and connect the attachment portion 5221 and the rail support portion 5222. As shown in Figure 38, the length of the attachment portion 5221 is approximately equal to the length of the base block 5210 in the X-axis direction, and its entire length is supported by the base block 5210. In addition, the rear ends of the attachment portion 5221 and the rail support portion 5222 are connected to each other by the connecting portion 5223a.

[0224] The rail support portion 5222 is longer than the mounting portion 5221 (i.e., longer than the base block 5210 ), and its tip portion protrudes forward beyond the base block 5210 and is positioned above the front drive portion 5300 .

[0225] The linear guide 5230 includes a rail 5231 extending in the X-axis direction and two carriages 5232 that run on the rail 5231 via rolling elements. The rails 5231 of the pair of linear guides 5230 are fixed to the upper surfaces of rail support portions 5222 of the right frame 5220R and the left frame 5220L, respectively. The length of the rail 5231 is approximately equal to the length of the rail support portions 5222, and the entire length of the rail 5231 is supported by the rail support portions 5222. A plurality of mounting holes (screw holes) are formed on the upper surface of the carriage 5232, and a plurality of through-holes corresponding to the mounting holes of the carriage 5232 are formed in the table 5240. The carriage 5232 is fastened to the table 5240 by fitting bolts (not shown) passed through each through-hole of the table 5240 into each mounting hole of the carriage 5232. The table 5240 and the four carriages 5232 form a sled.

[0226] Furthermore, the table 5240 is formed with mounting structures such as screw holes for mounting a test piece (not shown) such as a sheet, so that the test piece can be mounted directly on the table 5240. This eliminates the need for a mounting plate or other member for mounting the test piece, making it possible to reduce the weight of the moving parts to which the impact is applied, and to apply a high-fidelity impact to the test piece up to high frequency components.

[0227] As shown in Figure 39, each belt mechanism 5100 includes a toothed belt 5120, a pair of toothed pulleys (first pulley 5140, second pulley 5160) around which the toothed belt 5120 is wound, and a pair of belt clamps 5180 for fixing the toothed belt 5120 to the table 5240.

[0228] Four toothed belts 5120 are arranged in parallel between the right frame 5220R and the left frame 5220L. Each toothed belt 5120 is fixed to the table 5240 by belt clamps 5180 at two locations in the length direction.

[0229] As shown in FIG. 38 , the front drive unit 5300 includes a base block 5310 and four electric actuators 5320 (5320a, 5320b, 5320c, and 5320d) mounted on the base block 5310. The rear drive unit 5400 includes a base block 5410 and four electric actuators 5420 (5420a, 5420b, 5420c, and 5420d) mounted on the base block 5410. Each of the eight electric actuators has the same configuration as the electric actuator 100 according to the first embodiment, and although there are slight differences in the installation position, orientation, length of the components, and spacing between components, the basic configuration is the same. The front drive unit 5300 and the rear drive unit 5400 also have the same basic configuration.

[0230] A control unit (not shown) synchronizes and controls the driving of the motors of the electric actuators 5320a-d and 5420a-d based on the input acceleration waveform, thereby applying acceleration to the table 5240 in accordance with the acceleration waveform. In this embodiment, the control unit drives all eight motors to rotate back and forth in the same phase. This allows each electric actuator to output unidirectional rotational motion while utilizing regenerative energy, thereby applying acceleration to the table 5240.

[0231] Furthermore, the electric actuator according to the embodiment of the present invention can be used in place of various prime movers that output rotational motion (for example, engines, electric motors, hydraulic motors, air motors, steam turbines, etc.).

[0232] Furthermore, the electric actuator according to the embodiment of the present invention can be used not only for various electric vehicles such as electric two-wheeled, three-wheeled, or four-wheeled vehicles, or trucks, buses, and tractors having six or more wheels, but also as a prime mover for railway vehicles. That is, it can be used as a prime mover for any vehicle. It can also be used as a prime mover for aircraft such as airplanes (for example, propeller planes) and helicopters, or for ships. That is, the electric actuator according to the embodiment of the present invention can be used as a prime mover for any mobility.

[0233] Furthermore, the electric actuator according to the embodiments of the present invention can also be used as a prime mover for various industrial machines such as construction machines, agricultural machines, woodworking machines, machine tools, forging machines, injection molding machines, robots, and transport machines (for example, cranes, elevators, conveyors, etc.). In other words, an electric mobility equipped with the electric actuator according to the embodiments of the present invention obtains a unidirectional propulsive force from unidirectional rotational motion obtained by rotating the electric actuator forward and backward.

[0234] Furthermore, the electric actuator according to the embodiment of the present invention can also be used as a prime mover for various home appliances (washing machines, refrigerators, air conditioners, compressors, etc.).

[0235] Furthermore, the electric actuator according to the embodiment of the present invention can also be used as a prime mover for driving a hydraulic pump or a compressor.

[0236] The above is a description of exemplary embodiments of the present invention. The embodiments of the present invention are not limited to those described above, and various modifications are possible within the scope of the technical concept of the present invention. For example, the embodiments of the present invention also include appropriate combinations of embodiments explicitly shown as examples in the specification or obvious embodiments.

[0237] In the drive unit 100d described above, the screw shaft 41 of the ball screw 40 is directly connected to the rotating shaft 11 of the motor 10, but a configuration may also be adopted in which a reducer is provided in the drive unit and the motor 10 and ball screw 40 are connected via the reducer.

[0238] The electric drive system 90 (power supply system 90S) (FIG. 5) of the first embodiment may be configured to include a plug 291 and a battery 295e, as in the fourth embodiment.

[0239] Furthermore, the plug 291 and the battery 295e may be removed from the electric drive system 290 (power supply system 290S) (FIG. 16) of the fourth embodiment, and the circuit breaker 92 may be directly connected to the primary power source 91.

[0240] Furthermore, the circuit breaker 92, the electromagnetic switch 93, and / or the reactor 94 may be removed from the electric drive system 290 (power supply system 290S) ( FIG. 16 ) of the fourth embodiment, and these may be provided upstream of the plug 291 (on the primary power source side).

[0241] In addition, in the electric drive system 90 (power supply system 90S) (FIG. 5) of the first embodiment, an AC generator may be used as the primary power source 91.

[0242] In the electric drive system 290 (power supply system 290S) of the fourth embodiment (FIG. 16) or the electric drive system 690 (power supply system 690S) of the twelfth embodiment (FIG. 28), the battery 295e may be removed and a capacitor 95c with a large capacitance may be used so that the capacitor 95c also performs the power storage function of the battery 295e.

[0243] In the electric drive system 290 (power supply system 290S) ( FIG. 16 ) of the fourth embodiment, a configuration is adopted in which multiple inverters 95 b are provided for one servo amplifier 295 and each inverter 95 b is connected to a respective motor 10 (i.e., a configuration in which a power regeneration converter 95 a, a capacitor 95 c, and a DC bus 95 d are shared by multiple motors 10). However, the present invention is not limited to this configuration. For example, a configuration in which the servo amplifier 95 of the first embodiment ( FIG. 5 ) is provided for each motor 10 may be used. In this case, for example, the wiring is branched after the reactor 94, and a servo amplifier 95 is connected to each branch wiring. Alternatively, a reactor 94 may be provided for each servo amplifier 95, the wiring is branched after the electromagnetic switch 93, and the reactor 94 and servo amplifier 95 are connected to each branch wiring.

[0244] The electric actuator 100 according to the first embodiment of the present invention described above has a single drive unit 100d, the electric actuator 200 according to the fourth embodiment of the present invention has four drive units 200d, and the electric actuator 201 according to the fifth embodiment of the present invention has two drive units 200d, but the present invention is not limited to these configurations, and the electric actuator can be provided with any number of drive units.

[0245] The electric actuators 100, 200, and 201 described above each include a single crankshaft (crankshaft 70, crankshaft 270, crankshaft 270a), but the crankshaft may be divided into multiple crankshafts. For example, if the electric actuator includes four drive units, the crankshaft may be divided into two, with two drive units 100d connected to each crankshaft. In this case, the divided crankshafts 70 are interconnected by a winding transmission mechanism such as a gear mechanism or a belt mechanism so that the power of each crankshaft 70 is combined. Dividing the crankshaft 70 increases the degree of freedom in arranging the multiple drive units, thereby enabling miniaturization.

[0246] Although examples have been shown in which the electric actuator 100 is used in the vibration testing apparatus 1000 according to the eleventh embodiment, the tire testing apparatus 2000 according to the twelfth embodiment, the combined testing apparatus 3000 according to the thirteenth embodiment, the balance measurement apparatus 4000 according to the fourteenth embodiment, and the collision simulation testing apparatus 5000 according to the fifteenth embodiment, the electric actuator used in these apparatuses is not limited to the electric actuator 100 according to the first embodiment. For example, an electric actuator with two or more cylinders, such as the electric actuator 200 or the electric actuator 201, may also be used.

[0247] In each of the above embodiments, the motor 10 is an AC servo motor, but other types of electric motors that can control the drive amount (rotation angle), such as a DC servo motor or a stepping motor, may also be used as the motor 10.

[0248] In the above fourth and tenth embodiments, configurations in which a generator is provided in a power supply system are exemplified, but the generator may be provided in a power supply system of other embodiments, not limited to the fourth and tenth embodiments.

[0249] In each of the above embodiments, a power regeneration converter 95a is used that can return surplus regenerated power from the servo amplifier 95 to the primary power supply 91, but a converter that does not have a power regeneration function that returns surplus power to the primary power supply 91 may also be used. When a converter that does not have a power regeneration function is used, it is desirable to provide the servo amplifier 95 with a device that stores surplus power (for example, a large-capacity capacitor or a large-capacity battery) rather than providing the servo amplifier 95 with a regenerative resistor that absorbs regenerated power.

[0250] Figures 40 and 41 are diagrams showing modified examples of a power supply system that supplies power to an electric actuator according to each embodiment. In each of the above embodiments, a system that converts power supplied from a primary power source to drive an electric motor has been described, but the power supplied from the power source to the system is not limited to AC power. As shown in Figures 38 and 39, the motor 10 may be driven by supplying DC power from a battery 791 to an inverter via a converter. In this case, surplus power regenerated by the motor 10 that has not been charged (stored) in the capacitor 95c is stored in the battery 791 instead of being output to the primary power source.

[0251] 40 includes a bidirectional DC-DC converter 795a as a converter. First, a charger 792 is connected to a battery 791, and the battery 791 is charged with power supplied via the charger 792 from a plug 291 that is inserted into an outlet (not shown) of a primary power source. Next, the battery 791 is connected to a servo amplifier 795, and power from the battery 791 is supplied to an inverter 95b via the bidirectional DC-DC converter 795a to drive the motor 10. At the same time, surplus power regenerated by the motor 10 that has not been charged (stored) in the capacitor 95c is output to the battery 791 via the bidirectional DC-DC converter 795a.

[0252] 41 also includes a bidirectional DC-AC converter 895a upstream of a power regeneration converter 95a. First, a charger 792 is connected to a battery 791, and the battery 791 is charged with power supplied via the charger 792 from a plug 291 that is inserted into an outlet (not shown) of a primary power source. Next, the battery 791 is connected to a servo amplifier 895, and power from the battery 791 is supplied to an inverter 95b via the bidirectional DC-AC converter 895a and the power regeneration converter 95a to drive the motor 10. At the same time, surplus power regenerated by the motor 10 that has not been charged (stored) in the capacitor 95c is output to the battery 791 via the power regeneration converter 95a and the bidirectional DC-AC converter 895a.

[0253] In each of the above embodiments, the surplus power regenerated from the motor 10 that was not charged (stored) in the capacitor 95c was regenerated to the primary power source via the power regeneration converter 95a, but the surplus power regenerated from the motor 10 that was not charged (stored) in the capacitor 95c may also be regenerated to the primary power source without going through the power regeneration converter 95a.

[0254] Sixteenth Embodiment FIG. 42 is a diagram showing the circuit configuration of a power supply system (electric drive system) for an electric actuator according to a sixteenth embodiment.

[0255] The servo amplifier 95 shown in Figure 42 includes an inverter 95b, a capacitor 95c, two selector switches SW, a power regeneration converter 95a, and a PFC circuit 95e. The electric actuator 100 is mounted on an electric vehicle or other electric mobility and used as a prime mover for the electric mobility. The electric actuator 100 also includes a detection unit EN, a control device 96, and a storage device St.

[0256] The detector EN is, for example, an encoder, which detects the rotational position (rotational angle) [°] of the motor 10 and sends the detected rotational position to the control device 96 .

[0257] When the control device 96 detects that a primary power source 91 (external power source such as a system power source) has been connected to the external terminal Te during charging of the battery 295e mounted on the electric mobility, it controls the contacts of each changeover switch SW so that the power regeneration converter 95a is electrically connected to the primary power source 91 via the PFC circuit 95e and the external terminal Te, and controls the operation of the PFC circuit 95e and the power regeneration converter 95a so that power is supplied from the primary power source 91 to the battery 295e.

[0258] Furthermore, when the electric mobility vehicle is traveling, the control device 96 controls the contacts of each selector switch SW so that the power regeneration converter 95a is electrically connected to the inverter 95b via the capacitor 95c, and controls the operation of the power regeneration converter 95a and the inverter 95b so that power is repeatedly exchanged between the battery 295e and the motor 10, i.e., so that power running operation and regeneration operation are alternately repeated. The control device 96 drives the motor 10 by controlling the operation of the inverter 95b based on command values ​​pre-stored in the memory device St. For example, the control device 96 is configured with a motion controller, creates command values ​​based on a cam curve (described below), and stores the created command values ​​in the memory device St. When the electric mobility vehicle is traveling, i.e., when the electric actuator 100 is operating, the control device 96 controls the operation of the inverter 95b based on the command values ​​stored in the memory device St, thereby driving the motor 10 so that the connecting rod 60 rotates in one direction and moves back and forth linearly along the motion trajectory indicated by the cam curve.

[0259] When the battery 295e is being charged, the PFC circuit 95e converts AC power supplied from the primary power supply 91 into DC power and supplies it to the power supply regeneration converter 95a.

[0260] During powering operation (i.e., an operation mode in which the motor 10 is driven by power supplied from the battery 295e), the inverter 95b converts DC power stored in the capacitor 95c and the battery 295e into AC power and supplies it to the motor 10, thereby driving the motor 10. During regenerative operation (i.e., an operation mode in which power regenerated from the motor 10 is supplied to the capacitor 95c and the battery 295e), the inverter 95b converts AC power regenerated from the motor 10 into DC power and stores some or all of the DC power in the capacitor 95c. The inverter 95b charges the battery 295e by supplying surplus power not stored in the capacitor 95c to the battery 295e via the selector switch SW and the power supply regeneration converter 95a. That is, the inverter 95b supplies surplus power overflowing from the capacitor 95c, among the regenerated power regenerated to the capacitor 95c, to the primary power source 91. In other words, the inverter 95b supplies the battery 295e with surplus power corresponding to the power consumed by accelerating the motor 10 and the regenerative power generated by decelerating the motor 10. In other words, when the motor 10 repeatedly rotates forward and reverse, the inverter 95b outputs to the battery 295e the surplus power that is not consumed by accelerating the motor 10 out of the regenerative power regenerated from the motor 10.

[0261] The power supply regeneration converter 95a includes switching elements SW1 to SW8, a capacitor C1, and a transformer Tr. The inverter 95b includes switching elements SW9 to SW14. The switching elements SW1 to SW14 are, for example, insulated gate bipolar transistors (IGBTs).

[0262] When power from the battery 295e is supplied to the motor 10, the control device 96 alternately turns on and off the switching elements SW1, SW4 and the switching elements SW2, SW3, and the power smoothed by the capacitor C1 is transmitted from the primary coil L1 to the secondary coil L2 of the transformer Tr.

[0263] Furthermore, when power is supplied from the battery 295e to the motor 10, the power transmitted to the secondary coil L2 is rectified by the diodes connected in parallel to the switching elements SW5 to SW8, and is smoothed by the capacitor 95c.

[0264] In addition, when power from battery 295e is supplied to motor 10, switching elements SW9 to SW14 are repeatedly turned on and off by control device 96, and the power smoothed by capacitor 95c is converted into AC power with phases that differ by 120 degrees and supplied to motor 10.

[0265] Furthermore, when the power regenerated from the motor 10 is supplied to the capacitor 95c or the battery 295e, the AC power supplied from each of the three phases of the motor 10 is rectified by the diodes connected in parallel to the switching elements SW9 to SW14, and is smoothed by the capacitor 95c.

[0266] Furthermore, when the power regenerated from the motor 10 is supplied to the capacitor 95c or the battery 295e, the control device 96 repeatedly turns on and off the switching elements SW5, SW8 and the switching elements SW6, SW7, and the power smoothed by the capacitor 95c is transmitted from the secondary coil L2 of the transformer Tr to the primary coil L1.

[0267] Furthermore, when the power regenerated from the motor 10 is supplied to the capacitor 95c or the battery 295e, the power transmitted from the secondary coil L2 to the primary coil L1 is rectified by the diodes connected in parallel to the switching elements SW1 to SW4, and is smoothed by the capacitor C1.

[0268] When driving the motor 10 (power running), the DC power output from the battery 295e is converted to AC power by the power regeneration converter 95a, smoothed by the capacitor 95c, and converted to AC (e.g., pulse train) drive power by the inverter 95b. The drive power output from the inverter 95b is input to the motor 10, driving it to rotate.

[0269] When the motor 10 generates regenerative power (during regenerative operation), the regenerative power output from the motor 10 is converted to DC by the inverter 95b and input to the power regeneration converter 95a via the capacitor 95c. The power regeneration converter 95a converts the DC power input via the capacitor 95c into AC power and outputs it to the battery 295e.

[0270] That is, the servo amplifier 95 drives the motor 10 by supplying the motor 10 with power supplied from the battery 295e, and also regenerates the regenerative power generated in the motor 10 when the motor 10 switches from forward rotation to reverse rotation and the regenerative power generated in the motor 10 when the motor 10 switches from reverse rotation to forward rotation, and returns this power to the battery 295e.

[0271] FIG. 43 shows an example of a cam curve representing the relationship between the rotational position (rotation angle) [°] of the connecting rod 60 when it rotates about the rotation axis Ax2 and the stroke ratio of the connecting rod 60 when it reciprocates linearly. The solid line in FIG. 43 represents the cam curve discovered by the inventor. The dashed line in FIG. 43 represents a reference cam curve in which the relationship between the rotational position [°] of the connecting rod 60 when it rotates about the rotation axis Ax2 and the stroke ratio of the connecting rod 60 when it reciprocates linearly is expressed as a sine wave. The stroke ratio is the ratio of the movement of the connecting rod 60 to the length of a line segment, based on an arbitrary position on the line segment. For example, in Figures 44 and 50 (described later), assume that the position of the pin 52 when the connecting portion between the connecting rod 60 and the piston 50, i.e., the pin 52, is closest to the rotation axis Ax2 is Pn, the position of the pin 52 when it is farthest from the rotation axis Ax2 is Pf, and the midpoint between positions Pn and Pf is P0. In this case, the stroke ratio corresponding to position Pn is "+1", which is the value obtained by dividing the line segment Ln from position P0 to position Pn by the positive movement amount of the pin 52 when it moves from position P0 to position Pn. Also, the stroke ratio corresponding to position Pf is "-1", which is the value obtained by dividing the line segment Lf from position P0 to position Pf by the negative movement amount of the pin 52 when it moves from position P0 to position Pf. Note that the stroke ratio corresponding to position P0 is "0". When the stroke ratio is defined in this manner, the stroke ratio transitions from 0 to +1 as the pin 52 approaches the rotation axis Ax2, and then the stroke ratio transitions from +1 to 0 as the pin 52 moves away from the rotation axis Ax2, and then the stroke ratio transitions from 0 to -1 as the pin 52 moves away from the rotation axis Ax2, and then the stroke ratio transitions from -1 to 0 as the pin 52 approaches the rotation axis Ax2. In other words, as the connecting rod 60 makes reciprocating linear motion, the stroke ratio of the connecting rod 60 repeatedly fluctuates between -1 and +1.44 , if the rotational position of the connecting portion between the connecting rod 60 and the crankshaft 70, i.e., the crankpin 72, is 0° when the stroke ratio is 0, when the stroke ratio transitions from 0 to +1, the crankpin 72 rotates in one direction, and the rotational position of the crankpin 72 changes from 0° to 90° + α1°. Next, when the stroke ratio transitions from +1 to 0, the crankpin 72 continues to rotate in one direction, and the rotational position of the crankpin 72 changes from 90° + α1° to 180° + α2°. Next, when the stroke ratio transitions from 0 to −1, the crankpin 72 continues to rotate in one direction, and the rotational position of the crankpin 72 changes from 180° + α2° to 270° + α3°. Then, when the stroke ratio transitions from -1 to 0, the crank pin 72 continues to rotate in one direction, and the rotational position of the crank pin 72 changes from 270° + α3° to 360°. Also, in Figure 50, if the rotational position of the crank pin 72 when the stroke ratio is 0 is 0°, when the stroke ratio transitions from 0 to +1, the crank pin 72 rotates in one direction, and the rotational position of the crank pin 72 changes from 0° to 90° - β1°. Next, when the stroke ratio transitions from +1 to 0, the crank pin 72 continues to rotate in one direction, and the rotational position of the crank pin 72 changes from 90° - β1 to 180° - β2. Next, when the stroke ratio transitions from 0 to -1, the crank pin 72 continues to rotate in one direction, and the rotational position of the crank pin 72 changes from 180°-β2° to 270°-β3°. Then, when the stroke ratio transitions from -1 to 0, the crank pin 72 continues to rotate in one direction, and the rotational position of the crank pin 72 changes from 270°-β3° to 360°. In other words, the connecting rod 60 undergoes one-way rotational motion in conjunction with its reciprocating linear motion.

[0272] When the motor 10 is driven by command values ​​based on the reference cam curve shown in FIG. 43, rotation unevenness occurs when the connecting rod 60 (crank pin 72) rotates around the rotation axis Ax2, making it difficult to rotate the output shaft 75 smoothly. This places an extra load on the motor 10, which could reduce the efficiency of the motor 10.

[0273] The inventors discovered that by rotating the output shaft when the electric motor is not being driven, it is possible to obtain an electric motor command value that can smoothly drive a transmission mechanism that rigidly connects the motor rotation shaft to the output shaft. The solid-line cam curve shown in FIG. 43 was obtained by rotating the output shaft 75 in one direction when the motor 10 was not being driven, and a command value for driving the motor 10 was determined based on the cam curve. That is, the command value is determined based on the rotational position of the motor 10 rotated by rotating the output shaft 75 in one direction without driving the motor 10. For example, command values ​​based on the solid-line cam curve shown in FIG. 43 are pre-stored in the memory device St shown in FIG. 42, and when the electric actuator 100 is driven, the control device 96 drives the motor 10 based on the command value.

[0274] 44A to 44E are diagrams illustrating the operation of the connecting rod 60 corresponding to the solid-line cam curve shown in FIG. 43. In the example shown in FIG. 44, it is assumed that while the motor 10 is rotating forward, the connecting rod 60 (crank pin 72) rotates in one direction about the rotation axis Ax2 and the connecting rod 60 (pin 52) moves linearly toward the rotation axis Ax2, and while while the motor 10 is rotating reversely, the connecting rod 60 (crank pin 72) rotates in one direction about the rotation axis Ax2 and the connecting rod 60 (pin 52) moves linearly away from the rotation axis Ax2. Note that the rotational position of the connecting rod 60 and the reference position for the stroke ratio are not limited to the positions shown in FIG. 47.

[0275] First, as shown in FIG. 44A, when the pin 52 (connecting rod 60) is located at the reference position P0, the rotational position of the crank pin 72 (connecting rod 60) is set to 0°.

[0276] Next, as the motor 10 rotates in the forward direction, the crank pin 72 (connecting rod 60) rotates in one direction, and the connecting rod 60 moves linearly away from the motor 10 (so that the pin 52 approaches the rotation axis Ax2). As shown in FIG. 44B, when the pin 52 (connecting rod 60) moves to position Pn (the stroke ratio becomes +1), the rotational position of the crank pin 72 (connecting rod 60) becomes 90° + α1°.

[0277] Next, as the motor 10 rotates in the reverse direction, the crank pin 72 (connecting rod 60) rotates in one direction, and the connecting rod 60 moves linearly toward the motor 10 (so that the pin 52 moves away from the rotation axis Ax2). As shown in FIG. 44C, when the pin 52 (connecting rod 60) moves to position P0 (the stroke ratio becomes 0), the rotational position of the crank pin 72 (connecting rod 60) becomes 180° + α2°.

[0278] Furthermore, as the motor 10 rotates in the reverse direction, the crank pin 72 (connecting rod 60) rotates in one direction, and the connecting rod 60 moves linearly toward the motor 10 (the pin 52 moves away from the rotation axis Ax2). As shown in Figure 44D, when the pin 52 (connecting rod 60) moves to position Pf (the stroke ratio becomes -1), the rotational position of the crank pin 72 (connecting rod 60) becomes 270° + α3°. Note that α1° to α3° increase as the distance from the pin 52 to the crank pin 72 and the distance from the crank pin 72 to the rotation axis Ax2 increase.

[0279] As the motor 10 rotates in the forward direction, the crank pin 72 (connecting rod 60) rotates in one direction, and the connecting rod 60 moves linearly away from the motor 10 (so that the pin 52 approaches the rotation axis Ax2). As shown in FIG. 44E, when the pin 52 (connecting rod 60) moves to position P0 (the stroke ratio becomes 0), the rotational position of the crank pin 72 (connecting rod 60) becomes 360° (0°).

[0280] When a command value for driving the motor 10 is created as in the operation example of the connecting rod 60 shown in FIG. 44, that is, when a command value for driving the motor 10 is created using the cam curve shown in FIG. 43, the motor 10 is rotated forward so that the rotational position of the connecting rod 60 changes from 0° to 90° + α1° while the stroke ratio of the connecting rod 60 changes from 0 to +1, and the rotational position of the connecting rod 60 changes from 90° + α1° while the stroke ratio of the connecting rod 60 changes from +1 to 0. The motor 10 is rotated in the reverse direction so that the rotational position of the connecting rod 60 transitions from 180° + α2° to 240° + α3° while the stroke ratio of the connecting rod 60 transitions from 0 to -1, and the motor 10 is rotated in the forward direction so that the rotational position of the connecting rod 60 transitions from 240° + α3° to 360° while the stroke ratio of the connecting rod 60 transitions from -1 to 0.

[0281] One possible method for creating the solid-line cam curve shown in Figure 43 is to determine the rotational positions corresponding to each stroke ratio when the output shaft 75 (connecting rod 60) rotates in one direction using another motor when the motor 10 is not being driven, and then plot the relationship between the determined stroke ratio and rotational position on a two-dimensional coordinate system with rotational position on the horizontal axis and stroke ratio on the vertical axis. For example, if the unit stroke ratio is 0.1, the rotational positions corresponding to each stroke ratio are recorded when the stroke ratio of the connecting rod 60 is increased by 0.1 from 0 to +1, and the rotational positions corresponding to each stroke ratio are recorded when the stroke ratio of the connecting rod 60 is decreased by 0.1 from +1 to 0. Note that the stroke ratio obtained when the unit stroke ratio is increased 10 times when the stroke ratio is 0 is set to +1, and the stroke ratio obtained when the unit stroke ratio is decreased 10 times when the stroke ratio is +1 is set to 0. Furthermore, the rotational positions corresponding to each stroke ratio when the stroke ratio of the connecting rod 60 is decreased from 0 to −1 in increments of 0.1 are recorded, and the rotational positions corresponding to each stroke ratio when the stroke ratio of the connecting rod 60 is increased from −1 to 0 in increments of 0.1 are also recorded. Note that the stroke ratio when the unit stroke ratio is decreased 10 times when the stroke ratio is 0 is defined as −1, and the stroke ratio when the unit stroke ratio is increased 10 times when the stroke ratio is −1 is defined as 0. Furthermore, in the reference cam curve shown by the dashed line in FIG. 43 , if the amount of change in rotational position per unit stroke ratio when the stroke ratio transitions from 0 to +1 is 9°, the rotational position changes from 0° to 90° when the stroke ratio transitions from 0 to +1. Similarly, if the amount of change in rotational position per unit stroke ratio when the stroke ratio transitions from +1 to 0 is 9°, the rotational position changes from 90° to 180° when the stroke ratio transitions from +1 to 0. Similarly, if the rotational position per unit stroke ratio when the stroke ratio transitions from 0 to -1 is 9°, when the stroke ratio transitions from 0 to -1, the rotational position changes from 180° to 270°.Similarly, if the rotational position per unit stroke ratio when the stroke ratio changes from -1 to 0 is 9°, the rotational position changes from 270° to 360°. On the other hand, in the solid-line cam curve shown in Figure 43, if the change in rotational position per unit stroke ratio when the stroke ratio changes from 0 to +1 is 10°, the rotational position changes from 0° to 100° = 90° + 10° when the stroke ratio changes from 0 to +1. If the change in rotational position per unit stroke ratio when the stroke ratio changes from +1 to 0 is 11°, the rotational position changes from 100° to 210° = 180° + 30° when the stroke ratio changes from 0 to +1. Furthermore, if the amount of change in rotational position per unit stroke ratio when the stroke ratio transitions from 0 to -1 is 8°, then when the stroke ratio transitions from 0 to -1, the rotational position changes from 210° to 290° = 270° + 20°. If the amount of change in rotational position per unit stroke ratio when the stroke ratio transitions from -1 to 0 is 7°, then when the stroke ratio transitions from -1 to 0, the rotational position changes from 290° to 360°.

[0282] Furthermore, one of the factors that causes α1 [°] to α3 [°] is that, for example, the motor 10 is rigidly connected to the output shaft 75 by a mechanical mechanism (such as the piston 50 or the connecting rod 60), and therefore the amount of change in rotational position per unit stroke changes depending on the distance from the pin 52 to the crank pin 72 and the distance from the crank pin 72 to the rotation axis Ax2.

[0283] Figure 45A shows a cam curve discovered by the inventors, and Figure 45B shows a reference cam curve. The horizontal axis of the two-dimensional coordinate system shown in Figures 45A and 45B represents the rotational position (rotational angle) [°] of the connecting rod 60 when the connecting rod 60 rotates about the rotational axis of the crankshaft 70 upon starting the crankshaft 70, and the vertical axis represents the stroke ratio [%], speed ratio [%], or acceleration ratio [%] of the connecting rod 60 when the connecting rod 60 moves linearly upon starting the crankshaft 70. The solid line in Figure 45A represents the relationship between the rotational position and stroke ratio of the connecting rod 60, i.e., the cam curve discovered by the inventors. The dashed line in Figure 45A represents the result of first-order differentiation of the cam curve discovered by the inventors, and represents the relationship between the rotational position and speed ratio of the connecting rod 60. The dashed-dotted line in Figure 45A is the result of second-order differentiation of the stroke ratio of the cam curve discovered by the inventors, and shows the relationship between the rotational position of the connecting rod 60 and the acceleration ratio. The solid line in Figure 45B shows the reference cam curve. The dashed line in Figure 45B is the result of first-order differentiation of the stroke ratio of the reference cam curve, and shows the relationship between the rotational position of the connecting rod 60 and the speed ratio. The dashed-dotted line in Figure 45B is the result of second-order differentiation of the stroke ratio of the reference cam curve, and shows the relationship between the rotational position of the connecting rod 60 and the acceleration ratio.

[0284] The relationship between the rotational position of the connecting rod 60 and the acceleration ratio shown in Figure 45A (dash-dotted line) has a smaller peak acceleration ratio between 0° and 180° than the relationship between the rotational position of the connecting rod 60 and the acceleration ratio shown in Figure 45B (dash-dotted line). In other words, Figure 45A shows that the acceleration ratio of the connecting rod 60 is relatively small when the crankshaft 70 is started.

[0285] Thus, the inventors discovered that driving the motor 10 using command values ​​based on the cam curves (solid lines) shown in FIGS. 43 and 45A is effective in suppressing rotational irregularities in the output shaft 75. Because it is difficult to obtain the cam curves (solid lines) shown in FIGS. 43 and 45A using calculations or simulations, the output shaft 75 is forcibly rotated when the motor 10 is not being driven. The rotational position data output from the detection unit EN at this time is acquired, and a cam curve (solid line) capable of suppressing rotational irregularities in the output shaft 75 is obtained from the rotational position data. The command values ​​for the motor 10 are then determined based on the cam curve (solid line). This allows the output shaft 75 to rotate without placing an unnecessary load on the motor 10, thereby reducing the power consumption of the electric actuator 100.

[0286] FIG. 46 is a plan view of a power unit according to an embodiment of the present invention.

[0287] The power unit PU shown in Figure 46 includes three electric actuators 100-1 to 100-3. Each of the electric actuators 100-1 to 100-3 is similar to the electric actuator 100 described above, and detailed description thereof will be omitted. That is, each of the electric actuators 100-1 to 100-3 shown in Figure 46 includes three drive units 100d and three crankshafts 70. Note that the number of electric actuators 100 connected in the same direction as shown in Figure 46 is not limited to three, and may be two or four or more.

[0288] Furthermore, the power unit PU shown in Figure 46 has a structure simulating a three-cylinder engine. That is, the crankshaft 70 of electric actuator 100-1 and the crankshaft 70 of electric actuator 100-2 are connected to each other, and the crankshaft 70 of electric actuator 100-2 and the crankshaft 70 of electric actuator 100-3 are connected to each other. In this way, because the crankshafts 70 of the power unit PU are connected to each other, the outputs of the electric actuators 100-1 to 100-3 can be combined. That is, the transmission mechanisms of the electric actuators 100-1 to 100-3 can share an output shaft.

[0289] Figure 47 is a diagram showing cam curves for the connecting rods 60 of each of the electric actuators 100-1 to 100-3. The horizontal axis of the two-dimensional coordinate system shown in Figure 47 represents the rotational position [°] of the connecting rod 60, and the vertical axis represents the stroke ratio [%] of the connecting rod 60. The solid line shown in Figure 47 represents the relationship between the rotational position and stroke ratio of the connecting rod 60 in the electric actuator 100-1, the dashed line shown in Figure 47 represents the relationship between the rotational position and stroke ratio of the connecting rod 60 in the electric actuator 100-2, and the dashed line shown in Figure 47 represents the relationship between the rotational position and stroke ratio of the connecting rod 60 in the electric actuator 100-3.

[0290] The cam curves shown in FIG. 47 are assumed to differ from one another by 120° in rotational position.

[0291] FIG. 48 is a diagram showing a modified example of the power unit according to the embodiment of the present invention.

[0292] The power unit PU shown in FIG. 48 includes three electric actuators 100-1 to 100-3 whose crankshafts 70 are connected to one another, similar to the power unit PU shown in FIG.

[0293] The power unit PU shown in Figure 48 differs from the power unit PU shown in Figure 46 in that two of the electric actuators 100-1 to 100-3, that is, electric actuators 100-1 and 100-3, are arranged in parallel, and the remaining electric actuator 100-2 is arranged between the two electric actuators 100-1 and 100-3 arranged in parallel, facing the two electric actuators 100-1 and 100-3. Note that, as shown in Figure 48, the total number of at least two electric actuators 100 arranged in parallel and at least one electric actuator 100 arranged opposite each other is not limited to three, and may be four or more.

[0294] In addition, in each of the electric actuators 100-1 to 100-3 shown in Fig. 46, the motors 10 are driven by command values ​​determined based on the cam curves (solid lines) shown in Fig. 43, thereby rotating the connecting rods 60 and the crankshafts 70. In each of the electric actuators 100-1 and 100-3 shown in Fig. 48, the motors 10 are driven so that the connecting rods 60 operate based on the cam curves shown in Fig. 43. In addition, in the electric actuator 100-2 shown in Fig. 48, the motor 10 is driven by command values ​​determined based on the cam curves (solid lines) shown in Fig. 49, thereby rotating the connecting rods 60 and the crankshaft 70.

[0295] Figure 49 is a diagram showing an example of a cam curve that represents the relationship between the rotational position (rotation angle) [°] of the connecting rod 60 when the connecting rod 60 in the electric actuator 100-2 rotates about the rotation axis Ax2 and the stroke ratio when the connecting rod 60 makes a reciprocating linear motion. The solid line shown in Figure 49 represents the cam curve discovered by the inventor. The dashed line shown in Figure 49 represents a reference cam curve when the relationship between the rotational position [°] of the connecting rod 60 when the connecting rod 60 in the electric actuator 100-2 rotates about the rotation axis Ax2 and the stroke ratio when the connecting rod 60 makes a reciprocating linear motion is expressed as a sine wave.

[0296] When the motor 10 in the electric actuator 100-2 is driven by a command value based on the reference cam curve shown in Figure 43, rotation unevenness occurs when the connecting rod 60 rotates around the rotation axis Ax2, making it difficult to rotate the output shaft 75 smoothly, which places an extra load on the motor 10 and may reduce the efficiency of the motor 10.

[0297] Therefore, the inventors obtained the solid-line cam curve shown in FIG. 49 by rotating the output shaft 75 in one direction when the motors 10 of the electric actuators 100-1 to 100-3 shown in FIG. 48 were not being driven, and determined a command value for driving the motor 10 of the electric actuator 100-2 based on the cam curve. That is, the command value for the motor 10 of the electric actuator 100-2 is a value determined based on the cam curve of the connecting rod 60 of the electric actuator 100-2 when the output shaft 75 is rotated in one direction without driving the motors 10 of the electric actuators 100-1 to 100-3. For example, command values ​​based on the solid-line cam curve shown in FIG. 43 and command values ​​based on the solid-line cam curve shown in FIG. 49 are stored in advance in the memory device St shown in FIG. 42, and when driving the electric actuators 100-1 to 100-3, the control device 96 drives each motor 10 based on the command values ​​stored in the memory device St. This allows the output shaft 75 to rotate without placing an unnecessary load on each motor 10. As a result, it is possible to reduce the power consumption of the electric actuators 100-1 to 100-3. In other words, it is possible to reduce the power consumption of the power unit PU.

[0298] 50A to 50E are diagrams illustrating the operation of the connecting rod 60 corresponding to the solid-line cam curve shown in FIG. 49. In the example shown in FIG. 50, it is assumed that while the motor 10 is rotating forward, the connecting rod 60 (crank pin 72) rotates in one direction about the rotation axis Ax2 and the connecting rod 60 (pin 52) moves linearly toward the rotation axis Ax2, and while while the motor 10 is rotating reversely, the connecting rod 60 (crank pin 72) rotates in one direction about the rotation axis Ax2 and the connecting rod 60 (pin 52) moves linearly away from the rotation axis Ax2. Note that the rotational position of the connecting rod 60 and the reference position for the stroke ratio are not limited to the positions shown in FIG. 50.

[0299] First, as shown in FIG. 50A, when the pin 52 (connecting rod 60) is located at the reference position P0, the rotational position of the crank pin 72 (connecting rod 60) is set to 0°.

[0300] Next, as the motor 10 rotates in the forward direction, the crank pin 72 (connecting rod 60) rotates in one direction, and the pin 52 (connecting rod 60) moves linearly toward the rotation axis Ax2. As shown in FIG. 50B, when the pin 52 (connecting rod 60) moves to position Pn (the stroke ratio becomes +1), the rotational position of the crank pin 72 (connecting rod 60) becomes 90°-β1°.

[0301] Next, as the motor 10 rotates in the reverse direction, the crank pin 72 (connecting rod 60) rotates in one direction, and the pin 52 (connecting rod 60) moves linearly away from the rotation axis Ax2. As shown in FIG. 50C, when the pin 52 (connecting rod 60) moves to position P0 (the stroke ratio becomes 0), the rotational position of the crank pin 72 (connecting rod 60) becomes 180°-β2°.

[0302] Furthermore, as the motor 10 rotates in the reverse direction, the crank pin 72 (connecting rod 60) rotates in one direction and the pin 52 (connecting rod 60) moves linearly away from the rotation axis Ax2, and as shown in Figure 50D, when the pin 52 (connecting rod 60) moves to position Pf (the stroke ratio becomes -1), the rotational position of the crank pin 72 (connecting rod 60) becomes 270°-β3°. Note that β1° to β3° increase as the distance from the pin 52 to the crank pin 72 and the distance from the crank pin 72 to the rotation axis Ax2 increase.

[0303] As the motor 10 rotates in the forward direction, the crank pin 72 (connecting rod 60) rotates in one direction, and the pin 52 (connecting rod 60) moves linearly toward the rotation axis Ax2. As shown in FIG. 50E, when the pin 52 (connecting rod 60) moves to position P0 (the stroke ratio becomes 0), the rotational position of the crank pin 72 (connecting rod 60) becomes 360° (0°).

[0304] When a command value for driving the motor 10 is created as in the operation example of the connecting rod 60 shown in FIG. 50, that is, when a command value for driving the motor 10 is created using the solid cam curve shown in FIG. 49, the motor 10 is rotated forward so that the rotational position of the connecting rod 60 transitions from 0 [°] to 90 [°]-β1 [°] while the stroke ratio of the connecting rod 60 transitions from 0 to +1, and the rotational position of the connecting rod 60 transitions from 90 [°] to β1 [°] while the stroke ratio of the connecting rod 60 transitions from +1 to 0. ]-β1[°] to 180[°]-β2[°], while the stroke ratio of the connecting rod 60 transitions from 0 to -1, the motor 10 is rotated in the reverse direction so that the rotational position of the connecting rod 60 transitions from 180[°]-β2[°] to 240[°]-β3[°], while the stroke ratio of the connecting rod 60 transitions from -1 to 0, the motor 10 is rotated in the forward direction so that the rotational position of the connecting rod 60 transitions from 240[°]-β3[°] to 360[°].

[0305] An example of a method for creating the cam curve shown by the solid line in Figure 49 will be described. For example, the output shaft 75 (connecting rod 60) is rotated once in one direction without driving each motor 10. During the time period in which the output shaft 75 rotates once in one direction, the rotational positions corresponding to each stroke ratio of the connecting rod 60 of the electric actuator 100-2 as it moves by a unit stroke ratio are calculated, and the correspondence between the calculated stroke ratios and rotational positions is plotted on a two-dimensional coordinate system with the horizontal axis representing rotational position and the vertical axis representing stroke ratio. For example, if the unit stroke ratio is 0.1, the rotational positions corresponding to each stroke ratio are recorded when the stroke ratio of the connecting rod 60 is increased by 0.1 from 0 to +1, and the rotational positions corresponding to each stroke ratio are recorded when the stroke ratio of the connecting rod 60 is decreased by 0.1 from +1 to 0. Note that when the stroke ratio is 0 and the unit stroke ratio is increased 10 times, the stroke ratio is +1, and when the stroke ratio is +1 and the unit stroke ratio is decreased 10 times, the stroke ratio is 0. Furthermore, the rotational positions corresponding to each stroke ratio when the stroke ratio of the connecting rod 60 changes from 0 to -1 in increments of 0.1 are recorded, and the rotational positions corresponding to each stroke ratio when the stroke ratio of the connecting rod 60 changes from -0 to 0 in increments of 0.1 are also recorded. Note that when the unit stroke ratio is decreased 10 times when the stroke ratio is 0, the stroke ratio is -1, and when the stroke ratio is -1 and the unit stroke ratio is decreased 10 times, the stroke ratio is 0. Furthermore, in the dashed reference cam curve shown in FIG. 49 , if the change in rotational position per unit stroke ratio when the stroke ratio changes from 0 to +1 is 9°, then when the stroke ratio changes from 0 to +1, the rotational position changes from 0° to 90°. Similarly, if the change in rotational position per unit stroke ratio when the stroke ratio transitions from +1 to 0 is 9°, when the stroke ratio transitions from +1 to 0, the rotational position changes from 90° to 180°.Similarly, if the rotational position per unit stroke ratio when the stroke ratio transitions from 0 to −1 is 9°, the rotational position changes from 180° to 270° when the stroke ratio transitions from 0 to −1. Similarly, if the rotational position per unit stroke ratio when the stroke ratio transitions from −1 to 0 is 9°, the rotational position changes from 270° to 360° when the stroke ratio transitions from −1 to 0. On the other hand, in the solid-line cam curve shown in FIG. 49 , if the change in rotational position per unit stroke ratio when the stroke ratio transitions from 0 to +1 is 8°, the rotational position changes from 0° to 80° = 90° - 10° when the stroke ratio transitions from 0 to +1. Furthermore, if the change in rotational position per unit stroke ratio when the stroke ratio transitions from +1 to 0 is 7°, then when the stroke ratio transitions from 0 to +1, the rotational position changes from 1080° to 150° = 180° - 30°. If the change in rotational position per unit stroke ratio when the stroke ratio transitions from 0 to -1 is 10°, then when the stroke ratio transitions from 0 to -1, the rotational position changes from 150° to 250° = 270° - 20°. If the change in rotational position per unit stroke ratio when the stroke ratio transitions from -1 to 0 is 11°, then when the stroke ratio transitions from -1 to 0, the rotational position changes from 250° to 360°.

[0306] Furthermore, one of the factors that causes β1 [°] to β3 [°] shown in Figure 49 is, similar to one of the factors that causes α1 [°] to α3 [°], that is, for example, because the rotating shaft of motor 10 is rigidly connected to output shaft 75 by a mechanical mechanism (piston 50, connecting rod 60, etc.), the amount of change in rotational position per unit stroke changes depending on the distance from pin 52 to crank pin 72 and the distance from crank pin 72 to rotation axis Ax2.

[0307] FIG. 51A is a diagram showing the relationship between the frequency and effective load factor of the motor 10, and FIG. 51B is a diagram showing the relationship between the frequency and power consumption of the motor 10. Note that the horizontal axis of the two-dimensional coordinate system shown in FIG. 51A represents the frequency [Hz] of the motor 10, and the vertical axis represents the effective load factor [%] of the motor 10. The solid line in FIG. 51A represents the relationship between the frequency and effective load factor of the motor 10 in the power unit PU shown in FIG. 46, and the dashed line in FIG. 51A represents the relationship between the frequency and effective load factor of the motor 10 in the power unit PU shown in FIG. 48. The horizontal axis of the two-dimensional coordinate system shown in FIG. 51B represents the frequency [Hz] of the motor 10, and the vertical axis represents the power consumption [W] of the motor 10. The solid line in FIG. 51B represents the relationship between the frequency and power consumption of the motor 10 in the power unit PU shown in FIG. 46, and the dashed line in FIG. 51B represents the relationship between the frequency and power consumption of the motor 10 in the power unit PU shown in FIG. 48.

[0308] 51A and 51B, the power unit PU shown in Fig. 48 has a higher effective load factor than the power unit PU shown in Fig. 46, but can reduce power consumption. In other words, the load factor of the motor 10 can be reduced by 20% to 30%.

[0309] Figure 52 is a diagram showing a schematic configuration of the power system of an electric vehicle 1 equipped with the power unit PU shown in Figure 46 or 48 as a prime mover. The electric vehicle 1 includes a power transmission 2 and left and right drive shafts 3a and 3b. The power transmission 2 includes a transmission, a final reduction gear, and a differential gear (not shown). An output shaft 75 of the power unit PU is connected to an input shaft of the power transmission 2. The drive shafts 3a and 3b are connected to the left and right output shafts of the power transmission 2, respectively. Wheels W are attached to the ends of each drive shaft 3a, 3b. The power output from the power unit PU is transmitted to the drive shafts 3a, 3b via the transmission, final reduction gear, and differential gear of the power transmission 2, and the wheels W attached to the ends of the drive shafts 3a, 3b are rotated and driven.

[0310] The power unit PU according to the embodiment can be used in place of various prime movers that output rotational motion (for example, an engine, an electric motor, a hydraulic motor, an air motor, a steam turbine, etc.).

[0311] 52 is an example in which the electric actuator according to the embodiment of the present invention is applied to a four-wheeled electric vehicle, but the electric actuator according to the embodiment of the present invention can also be used in various types of vehicles such as two-wheeled vehicles, three-wheeled vehicles, or trucks, buses, tractors, etc. Furthermore, the electric actuator according to the embodiment of the present invention can also be used in hybrid vehicles, not limited to electric vehicles.

[0312] FIG. 53 is a block diagram showing a schematic configuration of a power supply system 790S (electric drive system 790) of the power unit PU shown in FIG. 46 or 48.

[0313] The power supply system 790S shown in FIG. 53 is mounted on, for example, the electric vehicle 1, and includes three inverters 95b, three capacitors 95c, two changeover switches SW, a power regeneration converter 95a, and a control device 96.

[0314] When the control device 96 detects that the primary power source 91 has been connected to the external terminal Te during charging of the battery 295e mounted on the electric vehicle 1, it controls the contacts of each changeover switch SW so that the power regeneration converter 95a is electrically connected to the primary power source 91 (external power source) via the external terminal Te, and also controls the operation of the power regeneration converter 95a so that power is supplied from the primary power source 91 to the battery 295e.

[0315] Furthermore, when the electric vehicle 1 is running (when the drive shafts 3a, 3b shown in FIG. 52 are rotating), the control device 96 controls the contacts of each selector switch SW so that the power regeneration converter 95a is electrically connected to each inverter 95b via each capacitor 95c, and controls the operation of the power regeneration converter 95a and each inverter 95b so that power is repeatedly exchanged between the battery 295e and each motor 10, i.e., so that power running operation and regeneration operation are alternately repeated. The control device 96 controls the operation of the power regeneration converter 95a and each inverter 95b based on command values ​​pre-stored in the memory device St. The command values ​​pre-stored in the memory device St are assumed to be determined based on the cam curve (solid line) shown in FIG. 43 and the cam curve (solid line) shown in FIG. 49.

[0316] Furthermore, during powering operation, each inverter 95b converts DC power stored in the capacitor 95c and the battery 295e into AC power and supplies it to the motor 10, thereby driving the motor 10. During regenerative operation, each inverter 95b converts AC power regenerated from the motor 10 into DC power and stores some or all of that DC power in the capacitor 95c. Each inverter 95b charges the battery 295e by supplying surplus regenerated power that is not stored in the capacitor 95c to the battery 295e via the selector switch SW and the power regeneration converter 95a. That is, each inverter 95b supplies surplus power overflowing from the capacitor 95c, among the regenerated power regenerated to the capacitor 95c, to the primary power source 91. In other words, each inverter 95b supplies surplus power corresponding to the power consumed by the acceleration of the motor 10 and the regenerated power, to the battery 295e. In other words, when the motor 10 repeatedly rotates forward and backward, each inverter 95b outputs to the battery 295e the surplus power regenerated from the motor 10 that is not consumed by accelerating the motor 10.

[0317] Furthermore, the power unit PU according to the embodiment can be used not only in automobiles but also as a prime mover for railway vehicles.

[0318] Figure 54 is a diagram showing a schematic configuration of a drive mechanism of a railway vehicle 600 when the power unit PU shown in Figure 46 or 48 is used as the prime mover of the railway vehicle. The railway vehicle 600 is equipped with a plurality of bogies 601 (two in the example shown in Figure 54). The bogies 601 are driving bogies equipped with the power unit PU as a drive device.

[0319] The bogie 601 includes two power units PU, two pairs of axles 603 (axles 603a, 603b), bearings 602, axle boxes (not shown), axle box support devices (not shown), and wheels 604. One ends of the axles 603a and 603b are connected to both ends of the power unit PU. The wheels 604 are attached to the other ends of the axles 603a and 603b.

[0320] Each bearing 602 is attached to an axle box, and each axle box is attached to a bogie frame 605 via an axle box support device. The bearings 602 and axle boxes are shock-absorbingly supported by the axle box support device relative to the bogie frame 605 (frame). Each axle 603 a and 603 b is rotatably supported by each bearing 602.

[0321] FIG. 55 is a diagram showing the circuit configuration of a power supply system 790S mounted on a railway vehicle 600 when the power unit PU is used as the prime mover of the railway vehicle.

[0322] The railway vehicle 600 includes a pantograph 692c as a current collector that contacts an overhead line 691b, which is a contact wire (contact wire). The railway vehicle 600 also includes a circuit breaker 92, an electromagnetic switch 93, and a reactor 94. AC power (e.g., single-phase AC) is supplied from a substation 691a to the overhead line 691b, and the AC power output from the pantograph 692c is supplied to the power supply system 790S via the circuit breaker 92, the electromagnetic switch 93, and the reactor 94.

[0323] The power supply system 790S is mounted on the railway vehicle 600 for each corresponding power unit PU (for example, the power unit PU shown in FIG. 54) or for each corresponding bogie (for example, the bogie 601 shown in FIG. 54). Note that the power supply system 790S may be configured for each railway vehicle 600 or for each train in which a plurality of railway vehicles 600 are coupled together, rather than for each power unit PU or bogie 601.

[0324] The power supply system 790S also includes a power regeneration converter 95a, an inverter 95b, and a capacitor 95c connected between the power regeneration converter 95a and the inverter 95b.

[0325] The power supply regeneration converter 95a includes a transformer Tr and switching elements SW11 to SW14. The switching elements SW11 to SW14 are, for example, IGBTs (insulated gate bipolar transistors). The switching elements SW11 to SW14 are repeatedly turned on and off, respectively, to rectify AC power supplied from the pantograph 692c to the switching elements SW11 to SW14 via the transformer Tr and output the rectified power to the capacitor 95c. Alternatively, the switching elements SW11 to SW14 are repeatedly turned on and off, respectively, to convert DC power supplied from the capacitor 95c to the switching elements SW11 to SW14 into AC power and output the AC power to the pantograph 692c via the transformer Tr. The power output from the capacitor 95c to the pantograph 692c is supplied to the overhead line 691b.

[0326] The inverter 95b includes switching elements SW15 to SW20. The switching elements SW15 to SW20 are, for example, IGBTs. By repeatedly turning on and off the switching elements SW15 to SW20, the DC power supplied from the capacitor 95c to the switching elements SW15 to SW20 is converted into three-phase AC power and output to the motor 10. Alternatively, by repeatedly turning on and off the switching elements SW11 to SW14, the three-phase AC power supplied from the motor 10 to the switching elements SW15 to SW20 is converted into DC power and output to the capacitor 95c.

[0327] When the motor 10 is powered, the control device 96 repeatedly turns on and off the switching elements SW15 to SW20 so that the power stored in the capacitor 95c is output to the motor 10.

[0328] Furthermore, when the motor 10 is regenerating, the control device 96 repeatedly turns on and off the switching elements SW15 to SW20 so that the power regenerated from the motor 10 is output to the capacitor 95c.

[0329] In addition, if the total power of the power stored in capacitor 95c and the power regenerated from motor 10 is less than the power required to drive motor 10, control device 96 repeatedly turns on and off switching elements SW11 to SW14 so that the shortfall in power is output from pantograph 692c to capacitor 95c.

[0330] In addition, if the total power of the power stored in capacitor 95c and the power regenerated from motor 10 is greater than the power required to drive motor 10, control device 96 repeatedly turns on and off switching elements SW11 to SW14 so that the excess power is output from capacitor 95c to pantograph 692c.

[0331] In the first embodiment, an axle box support system using an axle box and an axle box support device is employed, but the present invention is not limited to this configuration.

[0332] In addition, in the first embodiment, the drive unit 100d has the screw shaft 41 of the ball screw 40 directly connected to the rotating shaft 11 of the motor 10, but the drive unit may also be configured to have a reducer and connect the motor 10 and ball screw 40 via the reducer.

[0333] In addition, in FIG. 42, an AC generator may be used as the primary power source 91.

[0334] In addition, in FIG. 42, the battery 295e may be removed and a capacitor 95c with a large capacitance may be used, so that the capacitor 95c also serves as the storage function of the battery 295e.

[0335] Furthermore, in the first embodiment, the electric actuator 100 is provided with a single drive unit 100d, but the present invention is not limited to this configuration, and the electric actuator can be provided with any number of drive units.

[0336] Furthermore, although the electric actuator 100 includes a single crankshaft 70 in the first embodiment, it may be divided into multiple crankshafts. For example, if the electric actuator includes four drive units, the crankshaft may be divided into two, with two drive units 100d connected to each crankshaft. In this case, the divided crankshafts 70 are interconnected by a winding transmission mechanism such as a gear mechanism or a belt mechanism so that the power of each crankshaft 70 is combined. Dividing the crankshaft 70 increases the degree of freedom in arranging the multiple drive units, thereby enabling miniaturization.

[0337] Furthermore, the electric actuator or power unit according to the embodiment of the present invention can be used as a prime mover for the following devices in addition to electric mobility: For example, it may be used as a prime mover for railway trains, vibration test devices, tire test devices, dynamic balance combined test devices, uniformity test devices, balance measurement devices, crash simulation test devices, and various other power devices.

[0338] Furthermore, the electric actuator or power unit according to the embodiment of the present invention can be used in place of various prime movers that output rotational motion (for example, engines, electric motors, hydraulic motors, air motors, steam turbines, etc.).

[0339] Furthermore, the electric actuator or power unit according to the embodiment of the present invention can be used not only for various electric vehicles such as electric two-wheeled, three-wheeled, or four-wheeled vehicles, or trucks, buses, and tractors having six or more wheels, but also as a prime mover for railway vehicles. That is, it can be used as a prime mover for any vehicle. It can also be used as a prime mover for aircraft such as airplanes (for example, propeller planes) and helicopters, or for ships. That is, the electric actuator or power unit according to the embodiment of the present invention can be used as a prime mover for any mobility.

[0340] In addition, the electric actuator or power unit according to the embodiment of the present invention can also be used as a prime mover for various industrial machines such as construction machines, agricultural machines, woodworking machines, machine tools, forging machines, injection molding machines, robots, and transport machines (e.g., cranes, elevators, conveyors, etc.).

[0341] Furthermore, the electric actuator or power unit according to the embodiment of the present invention can also be used as a prime mover for various home appliances (washing machines, refrigerators, air conditioners, compressors, etc.).

[0342] Furthermore, the electric actuator or power unit according to the embodiment of the present invention can also be used as a prime mover for driving a hydraulic pump or compressor.

[0343] The above is a description of exemplary embodiments of the present invention. The embodiments of the present invention are not limited to those described above, and various modifications are possible within the scope of the technical concept of the present invention. For example, the embodiments of the present invention also include appropriate combinations of embodiments explicitly shown as examples in the specification or obvious embodiments.

[0344] In each of the above embodiments, the motor 10 is an AC servo motor, but other types of electric motors that can control the drive amount (rotation angle), such as a DC servo motor or a stepping motor, may also be used as the motor 10.

[0345] <Notes> An electric actuator according to one embodiment includes an electric motor, an inverter that drives the electric motor using power stored in a capacitor, a power regeneration converter that supplies battery power to the capacitor, and a motion converter having an input shaft to which rotational motion of the electric motor is transmitted and an output shaft that converts the rotational motion transmitted to the input shaft into unidirectional rotational motion and outputs the unidirectional rotational motion, wherein the motion converter converts the forward and reverse rotational motion transmitted to the input shaft into unidirectional rotational motion and outputs the unidirectional rotational motion when the drive device drives the electric motor to rotate repeatedly forward and reverse, the drive device regenerates regenerative power generated in the electric motor when the electric motor rotates repeatedly forward and reverse, and the power regeneration converter supplies surplus power of the regenerative power that has not been charged in the capacitor to the battery.

[0346] In the electric actuator, the drive device may supply surplus power of the regenerated power regenerated in the capacitor to a power supply.

[0347] Furthermore, an electric mobility according to one embodiment also includes an electric mobility having the above-mentioned electric actuator, a power transmission device in which the output shaft of the motion converter is connected to the input shaft, a drive shaft connected to the output shaft of the power transmission device, and wheels attached to the drive shaft.

[0348] The electric mobility may also include a selector switch, which electrically connects the power regeneration converter and an external power source when the battery is being charged, and which electrically connects the power regeneration converter and the inverter when the electric mobility is being driven.

[0349] The electric mobility may obtain a unidirectional propulsive force from unidirectional rotational motion obtained by rotating the electric actuator forward and backward.

[0350] In the electric actuator, the rotating body may be a crankshaft, and the connecting rod may be rotatably connected to a crank pin of the crankshaft.

[0351] In the electric actuator, the drive device may supply surplus power corresponding to the power consumed by the acceleration of the electric motor and the regenerative power to the power source.

[0352] Furthermore, in the above electric actuator, the drive device may supply power from a power source to the electric motor via the capacitor, and when the electric motor repeatedly rotates forward and reverse, surplus power regenerated from the electric motor that is not consumed in accelerating the electric motor may be output to the power source.

[0353] In the electric actuator, the drive device may be configured to drive the electric motor so that it repeatedly rotates forward and backward at a required frequency of 6 Hz or more.

[0354] In the electric actuator, the power regeneration converter may be configured as a bidirectional AC-DC converter.

[0355] In the electric actuator, the power supply may be a DC power supply, and the power regeneration converter may be a bidirectional DC-DC converter.

[0356] In addition, in the above-mentioned electric actuator, the motion converter may include a first motion converter that converts the forward / reverse rotational motion into reciprocating linear motion, and a second motion converter that converts the reciprocating linear motion into the unidirectional rotational motion.

[0357] Furthermore, in the above electric actuator, the motion converter may include a ball screw having a nut, a linear motion part fixed to the nut and moving linearly together with the nut, a rotating body that is rotatable around a rotation axis, and connecting rods rotatably connected to a part of the rotating body that is eccentric with respect to the rotation axis and to the linear motion part.

[0358] In the electric actuator, the rotating body may be a spindle, and the connecting rod may be rotatably connected to a protrusion formed at a position eccentric to the rotation axis of the spindle.

[0359] Moreover, the electric actuator may further include a control device that controls the drive device, and the control device may control the drive device so as to switch the rotation of the electric motor between forward and reverse rotation, avoiding a timing when the linear motion part reaches a dead point at which no rotational force is generated in the rotating body due to the movement of the linear motion part.

[0360] Moreover, the electric actuator may further include a control device that controls the drive device, and the control device may control the drive device so that the torque of the electric motor is limited at least at the timing when the linear motion part reaches a dead point where no rotational force is generated in the rotating body due to the movement of the linear motion part.

[0361] Furthermore, in the above electric actuator, the motion converter may include a first disk portion connected to the shaft of the electric motor and rotatable about a first rotation axis, a second disk portion connected to the output shaft of the motion converter and rotatable about a second rotation axis, and connecting rods rotatably connected to a portion of the first disk portion eccentric with respect to the first rotation axis and a portion of the second disk portion eccentric with respect to the second rotation axis.

[0362] Furthermore, a vibration testing apparatus according to one embodiment includes: a vibration table on which an object to be vibrated is attached; an electric motor; and a drive device that drives the electric motor using power stored in a capacitor, and further includes: an electric actuator that vibrates the vibration table in a predetermined direction; and a controller that controls the electric actuator so that the vibration table is vibrated at a predetermined amplitude and frequency, wherein regenerative power generated in the electric motor as a result of the vibration table being vibrated at the predetermined amplitude and frequency is regenerated and sent to the capacitor, and surplus power of the regenerative power is supplied to a power source.

[0363] Also, one embodiment of a tire testing apparatus includes an electric actuator including an electric motor having a rotating shaft connected to the center axis of a tire and a drive unit that drives the electric motor using power stored in a capacitor, and a controller that controls the electric actuator to cause the electric motor to generate a fluctuating torque, wherein the tire rotation speed is decelerated in accordance with the fluctuating torque of the electric motor, and regenerative power generated in the electric motor is regenerated and sent to the capacitor, and surplus power of the regenerative power is supplied to a power source.

[0364] Also, one embodiment of a dynamic balancing hybrid testing apparatus includes: a spindle to which a tire is attached; an electric actuator including an electric motor and a drive device that drives the electric motor using power stored in a capacitor; a motion converter that converts forward and reverse rotation output by the electric motor into unidirectional rotational motion; a transmission mechanism that transmits the unidirectional rotational motion output by the motion converter to the spindle; and a controller that controls the electric actuator so that the spindle rotates at a predetermined speed by rotating the electric motor forward and backward, wherein regenerative power generated in the electric motor is regenerated and sent to the capacitor as the spindle rotates at the predetermined speed, and surplus power of the regenerative power is supplied to a power source.

[0365] Also, one embodiment of a uniformity test apparatus includes: a rotating drum that contacts a tire; an electric actuator including an electric motor and a drive device that drives the electric motor using power stored in a capacitor; a motion converter that converts forward and reverse rotation output by the electric motor into unidirectional rotational motion and transmits the unidirectional rotational motion to the rotating drum; and a controller that controls the electric actuator so that the rotating drum rotates at a predetermined speed by rotating the electric motor forward and reverse, wherein regenerative power generated in the electric motor is regenerated and sent to the capacitor as the rotating drum rotates at the predetermined speed, and surplus power of the regenerative power is supplied to a power source.

[0366] Also, one embodiment of a balance measurement device includes an electric actuator including an electric motor and a drive device that drives the electric motor using power stored in a capacitor; a motion converter that converts the forward and reverse rotation output by the electric motor into unidirectional rotational motion; a transmission mechanism that transmits the unidirectional rotational motion output by the motion converter to a test piece; and a controller that controls the electric actuator so that the test piece rotates at a predetermined speed by rotating the electric motor forward and backward, wherein the balance measurement device regenerates regenerative power generated in the electric motor as the test piece rotates at the predetermined speed and sends it back to the capacitor, and supplies surplus power from the regenerated power to a power source.

[0367] Also, a collision simulation test apparatus according to one embodiment includes: a mounting portion to which a test specimen is attached; an electric actuator including an electric motor and a drive device that drives the electric motor using power stored in a capacitor; a motion converter that converts forward and reverse rotation output by the electric motor into unidirectional rotational motion; a transmission mechanism that converts the unidirectional rotational motion output by the motion converter into linear motion and transmits the linear motion to the mounting portion; and a controller that controls the electric actuator to apply a desired acceleration to the mounting portion by rotating the electric motor forward and backward, wherein the collision simulation test apparatus also includes a collision simulation test apparatus that regenerates power generated in the electric motor by applying the desired acceleration to the mounting portion, and sends it back to the capacitor, and supplies surplus power of the regenerated power to a power source.

[0368] Moreover, an electric actuator according to one embodiment includes: an electric motor capable of switching between forward and reverse rotation; a detection unit that detects the rotational position of the electric motor; a drive device that drives the electric motor in accordance with the rotational position and a command value; and a transmission mechanism that has an output shaft mechanically coupled to the rotating shaft of the electric motor and converts the forward and reverse rotation of the rotating shaft into rotation in one direction and transmits the rotation to the output shaft, wherein the drive device is configured such that the command value that rotates the output shaft in one direction in the transmission mechanism when the electric motor is rotated in the forward and reverse directions is set, and the command value is a value determined based on the rotational position of the electric motor that is rotated by rotating the output shaft in one direction.

[0369] Furthermore, the command value may be a value determined based on the rotational position of the electric motor detected by the detection unit when the electric motor is rotated forward and reverse by rotating the output shaft in one direction without driving the electric motor.

[0370] The transmission mechanism may also comprise: a first mechanism having a moving member held so as to be linearly movable, coupled to the rotating shaft of the electric motor, and causing the moving member to move back and forth in a linear manner in response to the forward and reverse rotation of the electric motor; and a second mechanism having a rotating member held so as to be rotatable, and a connecting rod rotatably connected to the rotating member at a first connecting portion offset from the center of rotation of the rotating member, the connecting rod being rotatably connected to the moving member at a second connecting portion spaced from the first connecting portion of the moving member, and causing the rotating member to rotate in one direction in response to the forward and reverse rotation of the electric motor; and the drive device may be configured so that a command value is set that is determined based on a cam curve of the connecting rod found from the rotation position detected by the detection portion when the output shaft is rotated once in one direction without driving the electric motor.

[0371] The transmission mechanism comprises: a first rotation mechanism having a first rotating member fixed to the rotating shaft of the electric motor; a rotatably held second rotating member; and a connecting rod rotatably connected to the second rotating member at a first connecting portion offset from the rotation center of the second rotating member, the connecting rod being rotatably connected to the first rotating member at a second connecting portion away from the rotation center of the first rotating member, and a second rotation mechanism that rotates the second rotating member in one direction in conjunction with the forward and reverse rotation of the electric motor; and the drive device may be configured so that a command value is set that is determined based on a cam curve of the connecting rod obtained from the rotation position detected by the detection unit when the output shaft is rotated one revolution in one direction without driving the electric motor.

[0372] The drive device may also be configured to drive the electric motor by supplying power from a power source to the electric motor, and to regenerate to the power source the regenerative power generated in the electric motor when the electric motor switches from forward rotation to reverse rotation and the regenerative power generated in the electric motor when the electric motor switches from reverse rotation to forward rotation.

[0373] In addition, in a power unit according to one embodiment, the electric actuators are arranged in parallel, and the transmission mechanisms share the output shaft.

[0374] Moreover, a power unit according to one embodiment includes a plurality of the electric actuators, at least two of which are arranged in parallel, at least one of which is arranged opposite the parallel-arranged electric actuators, and each of the transmission mechanisms shares the output shaft.

[0375] An electric mobility according to one embodiment includes the above-described power unit.

[0376] DESCRIPTION OF SYMBOLS 1 Electric vehicle 10 Motor (electric motor) 40 Ball screw 50, 250, 350 Piston (linear part, moving member) 52 Pin (second connecting part) 60, 135, 260, 360, 560 Connecting rod 64 Big end (rotating member) 70, 270, 270a Crankshaft (second mechanism) 72 Crank pin (first connecting part) 80 Generator 95, 295, 695, 795, 895, 995, 2850 Servo amplifier (drive device) 95a, 2851 Power regeneration converter 95b, 97b, 2852 Inverter 95c, 97c, 2853 Capacitor 96, 296, C2 Control device (control unit) 100, 200, 201, 300, 400, 500, 5320, 5320a, 5420 Electric actuator 100d, 200d, 300d, 400d, 500d Drive unit (first mechanism) 600 Railway vehicle

Claims

1. An electric actuator comprising: an electric motor capable of switching between forward and reverse rotation; a detection unit that detects the rotational position of the electric motor; a drive device that drives the electric motor in accordance with the rotational position and a command value; and a transmission mechanism having an output shaft mechanically coupled to a rotating shaft of the electric motor, and converting the forward and reverse rotation of the rotating shaft into rotation in one direction and transmitting the rotation to the output shaft, wherein the command value for rotating the output shaft in one direction in the transmission mechanism is set in the drive device when the electric motor is rotated in the forward and reverse directions, and the command value is a value determined based on the rotational position of the electric motor rotated by rotating the output shaft in one direction.

2. An electric actuator as described in claim 1, wherein the command value is a value determined based on the rotational position of the motor detected by the detection unit when the motor is rotated forward and reverse by rotating the output shaft in one direction without driving the motor.

3. The electric actuator according to claim 1, wherein the transmission mechanism comprises: a first mechanism having a moving member held so as to be movable in a linear manner, coupled to the rotating shaft of the electric motor, and causing the moving member to move back and forth in a linear manner in response to forward and reverse rotation of the electric motor; and a second mechanism having a rotating member held so as to be rotatable, and a connecting rod rotatably connected to the rotating member at a first connecting portion offset from the center of rotation of the rotating member, the connecting rod being rotatably connected to the moving member at a second connecting portion spaced from the first connecting portion of the moving member, and causing the rotating member to rotate in one direction in response to forward and reverse rotation of the electric motor; and wherein the drive device is set with a command value determined based on a cam curve of the connecting rod which is obtained from the rotational position detected by the detection portion when the output shaft is rotated once in one direction without driving the electric motor.

4. The electric actuator according to claim 1, wherein the transmission mechanism comprises: a first rotation mechanism having a first rotating member fixed to the rotating shaft of the electric motor; a rotatably held second rotating member; and a connecting rod rotatably connected to the second rotating member at a first connecting portion offset from the rotation center of the second rotating member, the connecting rod being rotatably connected to the first rotating member at a second connecting portion away from the rotation center of the first rotating member, and a second rotation mechanism for rotating the second rotating member in one direction in conjunction with the forward and reverse rotation of the electric motor; and wherein the drive device is set with a command value determined based on a cam curve of the connecting rod obtained from the rotation position detected by the detection unit when the output shaft is rotated once in one direction without driving the electric motor.

5. The electric actuator according to claim 1, wherein the drive device drives the electric motor by supplying electric power from a power source to the electric motor, and regenerates to the power source regenerative electric power generated in the electric motor when the electric motor switches from forward rotation to reverse rotation and regenerative electric power generated in the electric motor when the electric motor switches from reverse rotation to forward rotation.

6. A power unit in which the electric actuators according to claim 1 are arranged in parallel, and each of the transmission mechanisms shares the output shaft.

7. A power unit comprising a plurality of electric actuators according to claim 1, at least two of the electric actuators being arranged in parallel, at least one electric actuator being arranged opposite the electric actuators arranged in parallel, and each of the transmission mechanisms sharing the output shaft.

8. An electric mobility device equipped with the power unit according to claim 6.

9. An electric mobility device equipped with the power unit according to claim 7.

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