Electric actuators, electric mobility

Abstract

The purpose of the present invention is to improve the usage efficiency of regenerative energy. An electric actuator of one embodiment of the present invention comprises: an electric motor that repeats forward rotation and reverse rotation, at a desired frequency; and a motion converter that converts the forward / reverse rotational motion output from the electric motor to unidirectional rotational motion.

Description

Technical Field

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

Background Art

[0002] Industrial machines and electric vehicles that use an electric actuator such as a motor as a drive source are widely used. In order to achieve energy conservation in society, power saving of the drive source is strongly demanded. As a related technology, for example, there is Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The electric vehicle described in Patent Document 1 only performs regenerative power generation by a motor generator during coasting or braking, and there is room for improvement. <00000....30>

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide an electric actuator with improved power saving performance.

Means for Solving the Problems

[0006] [[ID=...45]] According to one aspect of the present invention, there is provided an electric actuator including: an electric motor that repeats forward and reverse rotations at a desired frequency; and a motion converter that converts the forward and reverse rotational motions output from the electric motor into a unidirectional rotational motion.

Effects of the Invention

[0007] According to one embodiment of the present invention, it is possible to provide an electric actuator with improved power saving performance. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of an electric actuator according to the first embodiment of the present invention. [Figure 2] This is a plan view showing the schematic structure of an electric actuator according to the first embodiment of the present invention. [Figure 3] This is a side view of the connecting rod according to the first embodiment of the present invention. [Figure 4] This is a side view of a crankshaft according to the first embodiment of the present invention. [Figure 5] This is a block diagram showing the schematic configuration of the power supply system (electric drive system) for an electric actuator according to the first embodiment of the present invention. [Figure 6] This is a diagram showing the circuit configuration of the electric drive system of the first embodiment. [Figure 7] (a) is the drive waveform of one cycle of the motor according to the first embodiment of the present invention, (b) is a graph showing the motor speed [rpm] in the first half of one cycle of the motor, (c) is a graph showing the motor speed in the second half of one cycle of the motor, (d) is a graph showing the motor torque [Nm] in the first half of one cycle of the motor, and (e) is a graph showing the motor torque in the second half of one cycle of the motor. [Figure 8] This diagram compares the operation of the first embodiment of the present invention with that of a conventional motor. [Figure 9] This figure illustrates control features for an electric actuator according to a second embodiment of the present invention. [Figure 10] This figure illustrates control features for an electric actuator according to a third embodiment of the present invention. [Figure 11] This is a perspective view of an electric actuator according to a fourth embodiment of the present invention. [Figure 12] This is a side view of the electric actuator according to the fourth embodiment. [Figure 13]It is a plan view of an electric actuator according to the fourth embodiment. [Figure 14] It is a front view of an electric actuator according to the fourth embodiment. [Figure 15] It is a configuration diagram of a crankshaft of an electric actuator according to the fourth embodiment. [Figure 16] It 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. [Figure 17] It is a perspective view of an electric actuator according to the fifth embodiment of the present invention. [Figure 18] It is a plan view of an electric actuator according to the fifth embodiment of the present invention. [Figure 19] It is a perspective view of an electric actuator according to the sixth embodiment of the present invention. [Figure 20] It is a perspective view of an electric actuator according to the seventh embodiment of the present invention. [Figure 21] It is a diagram showing the mechanism of a gear device of the seventh embodiment. [Figure 22] It is a perspective view of an electric actuator according to the eighth embodiment of the present invention. [Figure 23] It is a block diagram showing a schematic configuration of a power supply system (electric drive system) of an electric actuator according to the eighth embodiment. [Figure 24] It is a diagram showing a schematic configuration of a power train of an electric vehicle according to the ninth embodiment of the present invention. [Figure 25] It is a diagram showing a schematic configuration of a drive mechanism of a railway vehicle according to the tenth embodiment of the present invention. [Figure 26] It is a block diagram showing a schematic configuration of a power supply system (electric drive system) of a railway vehicle according to the tenth embodiment. [Figure 27] It is an external view of a tire test device according to the eleventh embodiment of the present invention. [Figure 28] It is an external view of a tire test device according to the eleventh embodiment. [Figure 29] It is a diagram showing the internal structure of a torque generating device of the eleventh embodiment. [Figure 30] This is a block diagram showing the schematic configuration of the power supply system of the 11th embodiment. [Figure 31] This is a side view showing the basic configuration of a uniformity and dynamic balance combined testing apparatus according to the 12th embodiment of the present invention. [Figure 32] The twelfth embodiment schematically illustrates a method for rotationally driving the spindle. [Figure 33] This is a front view of the measuring section of a balance measuring device according to the 13th embodiment of the present invention. [Figure 34] This is a side view of the measuring section of the balance measuring device according to the 13th embodiment. [Figure 35] This is a perspective view of a collision simulation test apparatus according to the 14th embodiment of the present invention. [Figure 36] This is a perspective view showing the structure of the test section and belt mechanism of the crash simulation test apparatus according to the 14th embodiment. [Figure 37] This is a block diagram showing a modified example of the schematic configuration of a power supply system for an electric actuator. [Figure 38] This block diagram shows another modified example of the schematic configuration of the power supply system for an electric actuator. [Modes for carrying out the invention]

[0009] The inventors have discovered that the efficiency of regenerative power utilization can be increased by driving an electric motor in a reverse rotation at a high repetition frequency. A high repetition frequency is, for example, 10 Hz or higher, but this is merely an example and is not limited to 10 Hz or higher.

[0010] Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same or corresponding items will be denoted by the same or corresponding reference numerals, and redundant explanations will be omitted. Furthermore, in each figure, if multiple items with the same reference numerals are shown, not all of those multiple items will necessarily be denoted by reference numerals, and the assignment of reference numerals will be appropriately omitted for some of those multiple items.

[0011] <First Embodiment> Figures 1 and 2 are a perspective view and a plan view of the electric actuator 100 according to the first embodiment of the present invention, respectively. In Figure 2, a portion of the piston 50, which will be described later, is shown in a cross-sectional view.

[0012] As shown in Figure 1, the electric actuator 100 comprises a drive unit 100d and a crankshaft 70. The electric actuator 100 may also include a servo amplifier 95 (drive device) and a control device 96, which will be described later in Figures 5 and 6.

[0013] In this specification, the term "electric actuator" may mean only a motor and the mechanism driven by the motor, or it may mean a motor and mechanism assembly (referred to as the mechanism) with a drive unit that drives the motor, or it may even include a control unit that controls the drive unit. Furthermore, if the electric actuator includes a drive unit or control unit, the drive unit or control unit may be housed in the same enclosure as the mechanism unit, or it may be configured as a separate device and connected to the mechanism unit by cables or the like.

[0014] The drive unit 100d comprises a motor 10, a bearing 30, a ball screw 40 (feed screw mechanism), a linear motion unit 50 (hereinafter referred to as "piston 50"), and a connecting rod 60.

[0015] 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, it is possible to perform reciprocating and counter-reverse driving at high frequencies of, for example, 100 Hz or higher.

[0016] 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 shaft 11 of the motor 10 by a shaft coupling 20.

[0017] The piston 50 is a cylindrical member with a hollow portion 50a formed therein that extends in the direction of the axis Ax1. The axis Ax1 is the centerline of the drive unit 100d and is a straight line common to the rotation axis of the motor 10 and the ball screw 40. The nut 42 of the ball screw 40 is housed, for example, at one end of the hollow portion 50a of the piston 50 (the left end in Figure 2) and fixed to the piston 50.

[0018] A pin 52 is attached to the other end of the piston 50 (the right end in Figure 2) perpendicular to the axis of the piston 50 (in other words, parallel to the crankshaft 70).

[0019] Figure 3 is a side view of the connecting rod 60. The connecting rod 60 has a small end portion 62 with a small-diameter pin hole 62a, a large end portion 64 with a large-diameter pin hole 64a, and a rod portion 66 connecting the small end portion 62 and the large end portion 64. The pin holes 62a and 64a are formed parallel to each other.

[0020] A pin 52 is inserted into the pin hole 62a of the small end 62, for example, via a bush (not shown). The ends of the pin 52 are inserted into a pair of pin holes 50b (Figure 2) formed at 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 able to rotate within a certain angular range with the pin 52 as the pivot axis. In addition to the pin 52 (first pin), the connecting rod 60 is also rotatably connected to the crank pin 72 (second pin), which will be described later.

[0021] Figure 4 is a side view of the crankshaft 70. The crankshaft 70 has a pair of coaxially arranged crank journals 71 (i.e., their axes of rotation or centerlines coincide), a crank pin 72 positioned eccentrically with respect to the axis of the crank journals 71 (i.e., axis Ax2, which is the axis of rotation of the crankshaft 70), a pair of crank arms 73 connecting the crank journals 71 and the crank pin 72, a pair of balance weights 74 provided on the opposite side of each crank arm 73 with respect to axis Ax2, and an output shaft 75 coaxially coupled to one of the crank journals 71. The balance weights 74 are formed to counteract the imbalance caused by the eccentric crank pin 72 and crank arm 73 with respect to axis Ax2.

[0022] The crankshaft 70 is a rotating body that is rotatably supported by a pair of bearings (not shown) fixed to the frame (not shown) at a pair of crank journals 71.

[0023] The crank pin 72 is an eccentric pin that is offset from the axis of rotation of the crankshaft 70, and is inserted into the pin hole 64a of the large end 64 of the connecting rod 60, for example, via a bush (not shown). This rotatably connects the crankshaft 70 to the connecting rod 60.

[0024] Furthermore, for example, self-lubricating bushings are used for the bushings that engage with the pin holes 62a and 64a of the connecting rod 60. Alternatively, another type of bearing, such as a rolling bearing, may be used instead of the bushings.

[0025] The motor 10 is driven so that the shaft 11 repeatedly reciprocates within a predetermined angular range. In other words, the motor 10 repeatedly rotates in forward and reverse directions at a predetermined frequency. The rotation of the motor 10 (more specifically, the reciprocating rotational 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, reciprocates linearly along the axis Ax1 with a predetermined stroke. That is, the ball screw 40 functions as a first motion converter that converts the reciprocating rotational 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 by the connecting rod 60 to the eccentric crankpin 72 of the crankshaft 70 and converted into rotational motion of the crankshaft 70. In other words, a crank mechanism (more specifically, a slider-crank mechanism) is formed by the connecting rod 60 and the crankshaft 70 (as well as a pin 52 that pivotably supports the connecting rod 60 and a bearing (not shown) that rotatably supports the crankshaft 70) to act as a second motion transducer that converts reciprocating motion (reciprocating linear motion) into unidirectional rotational motion (hereinafter referred to as "unidirectional rotational motion").

[0026] Figure 5 is a block diagram showing the schematic configuration of the power supply system 90S (electric drive system 90) that supplies driving power to the motor 10. Figure 6 is a diagram showing the circuit configuration of the electric drive system 90. The power supply system 90S, together with the motor 10, constitutes the electric drive system 90.

[0027] The primary power supply 91 is a commercial power supply or power supply device, for example, it supplies three-phase alternating current power. The power supplied from the primary power supply 91 (hereinafter referred to as "system power") is supplied to the 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 alternating current supplied from the primary power supply 91 into drive power for the motor 10, and supplies the power supplied from the primary power supply 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 the control device 96 in a communicative manner and operates according to the control of the control device 96.

[0028] 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, and is, for example, a PWM converter that converts the power supply current into a sine wave using PWM (Pulse Width Modulation) control. The power regeneration converter 95a may also perform power conversion using a 120° energization method. The inverter 95b is, for example, a PWM inverter that controls the output power using PWM control. In this embodiment, the power regeneration converter 95a has the function of rectifying the AC supplied from the primary power supply 91 during powering operation (i.e., the operating mode in which the motor 10 is driven by power supplied from the servo amplifier 95) and the function of generating AC 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 powering operation and a converter dedicated to power regeneration may be provided separately.

[0029] The power regeneration converter 95a comprises switching elements SW1 to S14, a capacitor (or condenser) C, and a transformer Tr. The inverter 95b comprises switching elements SW15 to SW20. Note that the switching elements SW1 to SW20 are, for example, IGBTs (Metal Oxide Semiconductor Field Effect Transistors).

[0030] When power supplied 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) is supplied to the motor 10, the control device 96 repeatedly turns on and off switching elements SW1 to SW6 according to 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.

[0031] Furthermore, when power supplied from the primary power supply 91 is supplied to the motor 10, the power rectified by the switching elements SW1 to SW6 is smoothed by the capacitor C.

[0032] Furthermore, when power supplied from the primary power supply 91 is supplied to the motor 10, the control device 96 repeatedly turns the switching elements SW7, SW10 and SW8, SW9 on and off alternately, thereby transferring the power smoothed by the capacitor C from the primary coil L1 to the secondary coil L2 of the transformer Tr.

[0033] Furthermore, when power supplied from the primary power supply 91 is supplied to the motor 10, the control device 96 repeatedly turns switching elements SW11, SW14 and SW12, SW13 on and off alternately, thereby rectifying the power transmitted from the primary coil L1 to the secondary coil L2.

[0034] Furthermore, when power supplied from the primary power supply 91 is supplied to the motor 10, the power rectified by the switching elements SW11~SW14 is smoothed by the capacitor 95c.

[0035] Furthermore, when power supplied from the primary power supply 91 is supplied to the motor 10, the control device 96 repeatedly turns the switching elements SW15 to SW20 on and off, so that the power smoothed by the capacitor 95c is converted into AC power with a phase difference of 120 degrees and supplied to the motor 10.

[0036] Furthermore, when 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.

[0037] Furthermore, when 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~SW20 is smoothed by the capacitor 95c.

[0038] Furthermore, when power regenerated from the motor 10 is supplied to the servo amplifier 95, the control device 96 repeatedly turns switching elements SW11, SW14 and SW12, SW13 on and off alternately, thereby transferring power smoothed by the capacitor 95c from the secondary coil L2 of the transformer Tr to the primary coil L1.

[0039] Furthermore, when 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 from the switching elements SW7 to SW10.

[0040] Furthermore, when 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 SW7 to SW10 is smoothed by the capacitor C.

[0041] Furthermore, when power regenerated from the motor 10 is supplied to the servo amplifier 95, the control device 96 repeatedly turns the switching elements SW1 to SW6 on and off, so that the power smoothed by the capacitor C is converted into AC power and supplied to the primary power supply 91.

[0042] When the motor 10 is driven (during powering operation), 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 back into AC driving power (e.g., a pulse train) by the inverter 95b. The driving power output from the inverter 95b is input to the motor 10, which rotates the motor 10.

[0043] 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 DC bus 95d. One DC bus 95d is formed from a pair of positive and negative conductors. The power regeneration converter 95a converts the DC power supplied from the DC bus 95d into sinusoidal AC and outputs it to the primary power supply via the reactor 94, electromagnetic switch 93, and circuit breaker 92.

[0044] Figure 7(a) is a graph showing the drive waveform of motor 10 for one cycle. Figure 7(b) is a simplified graph showing the change in motor speed [rpm] of motor 10 during the first half of one cycle, and Figure 7(c) is a simplified graph showing the change in motor speed of motor 10 during the second half of one cycle. Figure 7(d) is a simplified graph showing the change in torque [Nm] of motor 10 during the first half of one cycle, and Figure 7(e) is a simplified graph showing the change in torque of motor 10 during the second half of one cycle. In Figure 7(a), the horizontal axis represents time t, and the vertical axis represents the angular position θ of axis 11. In Figures 7(b) and 7(c), the horizontal axis represents time t, and the vertical axis represents the rotational speed of motor 10. In Figures 7(d) and 7(e), the horizontal axis represents time t, and the vertical axis represents the torque of motor 10. The time intervals in Figures 7(a) to 7(e) are mutually identical.

[0045] Motor 10 is driven so that the angular position θ of the shaft 11 repeatedly fluctuates in the range of -θa to θa according to a sinusoidal drive waveform while time t repeatedly elapses from time t0 to time t6. Note that the drive waveform of motor 10 is not limited to a sinusoidal waveform. When the drive waveform of motor 10 is a sinusoidal drive waveform, the waveform of the motor's rotational speed (revolutions per minute) is actually a cosine waveform. However, in Figures 7(b) and 7(c), for the sake of explanation, the waveform of the motor's rotational speed is simplified to show a constant speed change in the range of large changes, and no speed change (constant rotations per minute) in the range of small changes.

[0046] In section A shown in Figure 7(a), more specifically, in the first period from time t0 to time t1, the shaft 11 is accelerated in the positive rotational direction. That is, in the first period, the rotational 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 (motoring operation). For example, in the first period, the power stored in capacitors 95c and C is supplied to the motor 10, and any remaining power is supplied to the motor 10 from the primary power supply 91.

[0047] In section B shown in Figure 7(a), more specifically, in the second period from time t2 to time t3, the shaft 11 is decelerated in the positive rotation direction. That is, in the second period, the rotational speed of the motor 10 decreases during forward rotation, and negative torque (deceleration torque) is generated. At this time, regenerative power is supplied from the motor 10 to the servo amplifier 95 (regeneration). For example, in the second period, the power regenerated from the motor 10 is stored in capacitors 95c and C.

[0048] In section C shown in Figure 7(a), more specifically, in the third period from time t3 to time t4, the shaft 11 is accelerated in the negative rotation direction. That is, in the third period, the rotational speed of the motor 10 during reverse rotation increases, 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 (motoring operation). For example, in the third period, the power stored in capacitors 95c and C is supplied to the motor 10, and any remaining power is supplied to the motor 10 from the primary power supply 91.

[0049] In section D shown in Figure 7(a), more specifically, in the fourth period from time t5 to time t6, the shaft 11 is decelerated in the negative rotation direction. That is, in the fourth period, the rotational speed of the motor 10 decreases during reverse rotation, and a negative torque (deceleration torque) is generated. At this time, regenerative power is supplied from the motor 10 to the servo amplifier 95 (regenerative operation). For example, in the fourth period, the power regenerated from the motor 10 is stored in capacitors 95c and C.

[0050] In this way, as the traction and regeneration are repeated, the power stored in capacitors 95c and C during regeneration can be used to drive the motor 10 during the next traction operation, thereby reducing the power supplied to the motor 10 from the primary power supply 91 during the next traction operation. This makes it possible to save power in the electric drive system 90. In addition, by repeatedly accelerating (traction) and decelerating (regeneration) while alternating directions, the shaft 11 of the motor 10 rotates back and forth. This reciprocating rotation is repeated at a maximum repetition frequency of 500 Hz, for example.

[0051] Thus, 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 repeated alternately. Short-term voltage fluctuations in the DC bus 95d associated with the exchange of power with the motor 10 (for example, about one cycle of the motor 10) are mainly adjusted (in other words, leveled) by the capacitor 95c. As a result, most of the power supplied to the motor 10 in sections A and C is recovered as regenerative power in sections B and D and reused, making it possible to drive the motor 10 with almost no consumption of power supplied from the primary power supply 91.

[0052] [Table 1]

[0053] Table 1 shows the driving conditions and power consumption measurement results for the electric actuator 100 of this embodiment.

[0054] "Frequency F" is the number of times the drive cycle shown in Figure 7 is repeated per second. Power consumption was measured by varying the frequency F in 25Hz increments up to a maximum of 200Hz. However, the minimum frequency was set to 10Hz, which allows for stable operation, rather than 0Hz.

[0055] "Torque T0" is the maximum value (amplitude) of the relative torque (expressed as a percentage of the rated torque) of the motor shaft 11 of the motor 10. "Power consumption value W" A This value represents the average power consumption of the entire electric drive system 90, measured by a power measuring instrument PM upstream of the circuit breaker 92 (Figure 5). "Output power value W" B This value represents the average power output from the servo amplifier 95 to the motor 10. The "energy saving rate R" is the percentage of power consumption reduced by regenerating power, where R = 100 × (1 - W) A / W B It is calculated by ).

[0056] 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, an energy saving rate of over 90% can be achieved in the low-frequency range of 75 Hz or less.

[0057] The power consumption reduction effect of the electric actuator 100 in this embodiment can be obtained even when the repetition frequency of the motor 10's reciprocating rotation is set to 1 Hz. However, when the repetition frequency is set to 3 Hz or higher (more preferably 5 Hz or higher), the regenerative power is efficiently reused by the electric actuator 100 itself, resulting in a better energy saving rate.

[0058] Figure 8(a) is a schematic graph showing the drive waveform of a typical conventional motor, and Figure 8(b) is a schematic graph showing the drive waveform of the motor 10 in this embodiment.

[0059] As shown in Figure 8(a), in a typical conventional motor drive, the motor is accelerated to a predetermined rotational speed in section T1, then driven continuously at a constant rotational speed (section T2), and finally decelerated and stopped at the end of section T3. In such a drive, regenerative power is generated only in section T3. Therefore, the effect of reducing power consumption by utilizing regenerative power is minimal.

[0060] On the other hand, in this embodiment, as shown in Figure 8(b), the motor 10 repeatedly accelerates (powering) and decelerates (regenerative) at a high frequency throughout the entire period from the start to the end of the drive. The regenerative power generated during deceleration is immediately consumed in the next powering operation. In other words, the generation and consumption of regenerative power are continuously repeated from the start to the end of the drive. As a result, in this embodiment, the effect of reducing power consumption by utilizing regenerative power is extremely large.

[0061] As described above, the electric actuator 100 according to this embodiment is equipped with a motion converter that converts the forward and reverse rotational motion output by the motor 10 into unidirectional rotational motion. This allows the motor 10 to rotate in forward and reverse directions to actively generate regenerative energy while outputting unidirectional rotational motion. Therefore, it is possible to obtain unidirectional rotational motion, which is used in mobility devices such as automobiles and trains, with less power consumption than when it is obtained directly from the shaft of the motor 10.

[0062] <Second Embodiment> Figure 9 illustrates the control features of the electric actuator according to this embodiment. Figure 9(a) shows an example of control in the electric actuator 100 according to the first embodiment, and Figure 9(b) shows an example of control in the electric actuator according to this embodiment.

[0063] The vertical axes in Figures 9(a) and 9(b) indicate the position of the piston 50 performing reciprocating linear motion. Positions 100 and -100 indicate the position of the piston 50 when the slider-crank mechanism of the electric actuator is at its bottom dead center and top dead center, respectively.

[0064] The horizontal axis in Figures 9(a) and 9(b) shows the phase of the crankshaft 70 performing unidirectional rotational motion. Phase 90 and phase 270 represent the phase of the crankshaft 70 when the slider-crank mechanism of the electric actuator is at its bottom dead center and top dead center, respectively.

[0065] The configuration of the electric actuator according to this embodiment is the same as that of the electric actuator 100 of the first embodiment, except that the control device 96 is configured to perform control (phase shift control) of the motor 10, which will be described later. Therefore, in the electric actuator according to this embodiment as well, the reciprocating rotational motion of the motor 10 is 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 sinusoidal waveforms in Figures 9(a) and 9(b) show the relationship between the position of the piston 50 and the phase of the crankshaft 70 in these electric actuators.

[0066] In the electric actuator 100 according to the first embodiment, the control device 96 controls the servo amplifier 95 so as shown in Figure 9(a) that it switches the rotation direction of the motor 10 from forward to reverse at timing t1 when the piston 50 reaches the bottom dead center, and switches the rotation direction of the motor 10 from reverse to forward at timing t2 when the piston 50 reaches the 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 on the crankshaft 70 by the movement of the piston 50. In other words, it is possible to convert reciprocating linear motion into unidirectional rotational motion.

[0067] Incidentally, when switching between forward and reverse rotation of the motor 10, a large torque is generated in the motor 10. Therefore, if the rotation direction is switched at the top dead center and bottom dead center, where the force transmitted from the piston 50 to the crankshaft 70 is not applied in the tangential direction (rotational direction) but only in the radial direction, a large force is generated in the radial direction of the crankshaft 70 due to the large torque generated in the motor 10. As a result, vibration occurs in the crankshaft 70, which can hinder the smooth rotation of the crankshaft 70.

[0068] 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 the timings t1 and t3 when the piston 50 reaches bottom dead center and top dead center. For example, as shown in Figure 9(b), the control device 96 may control the servo amplifier 95 to switch the direction of rotation from forward to reverse at a timing t3 that is slightly later than the timing t1 when the piston 50 reaches bottom dead center, and to switch the direction of rotation from reverse to forward at a timing t4 that is slightly later than the timing t2 when the piston 50 reaches top dead center. Note that this time difference (t3-t1, t4-t2) corresponds to, for example, about 0.5 degrees of the phase of the crankshaft 70, and the displacement that occurs during this time is generally within the range of play (play) of the crank mechanism. Note that the above time difference (t3-t1, t4-2) can be 1.5 degrees or less of the phase of the crankshaft 70, and it is desirable that it be 1 degree or less. Furthermore, it is even more desirable to keep the temperature below 0.5 degrees.

[0069] In this way, by controlling the motor 10 to switch the direction of rotation at positions offset from the top dead center and bottom dead center, it becomes possible to apply rotational force at the top dead center and bottom dead center while suppressing the force applied to the crankshaft 70 in the radial direction. Therefore, the electric actuator according to this embodiment can output smoother unidirectional rotation while suppressing vibrations compared to the electric actuator 100 according to the first embodiment.

[0070] Specific control methods include applying a constant phase difference between the phase of the crankshaft 70 and the control phase of the motor 10 throughout the entire control section, or gradually increasing and decreasing (eliminating) the phase difference in the vicinity of the dead center (top dead center, bottom dead center) (for example, within a range of ±10° centered on the dead center).

[0071] Although Figure 9(b) shows an example where the rotation direction is switched after passing the top dead center and bottom dead center, the control device 96 may also control the servo amplifier 95 to switch the rotation direction before passing the top dead center and bottom dead center.

[0072] <Third Embodiment> Figure 10 illustrates the control features of the electric actuator according to this embodiment. Figure 10(a) shows 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 Figure 10(b) shows the relationship between the torque limit and the phase of the crankshaft 70 in the electric actuator according to this embodiment.

[0073] The configuration of the electric actuator according to this embodiment is the same as that of the electric actuator 100 in the first embodiment, except that the control device 96 is configured to perform control (load suppression control) of the motor 10, which will be described later.

[0074] As described above in the second embodiment, when the rotation direction of the motor 10 is switched at the top dead center and bottom dead center, a large force is applied to the crankshaft 70 in the radial direction, making it easy for vibration to occur 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 at the timing when it reaches dead center (top dead center, bottom dead center). The control device 96 may, for example, as shown in Figure 10, limit the torque of the motor 10 near the top dead center and bottom dead center where the rotation direction is switched (θ1~θ2, θ3~θ4), and control the motor 10 within the range of the limited torque. This prevents excessive force from being applied to the crankshaft 70 in the radial direction, and thus suppresses the generation of vibrations that hinder the smooth rotation of the crankshaft 70. Accordingly, the electric actuator according to this embodiment can output smoother unidirectional rotation while suppressing vibrations compared to the electric actuator 100 according to the first embodiment.

[0075] <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 equipped with multiple drive units. The electric actuator 200 of the fourth embodiment of the present invention, which will be described next, is equipped with four drive units 200d. The electric actuator 200 may include a servo amplifier 295 (drive device) and a control device 296, which will be described later in Figure 16.

[0076] Figure 11 is a perspective view of the electric actuator 200 according to the fourth embodiment of the present invention. Figures 12 to 14 are a side view, a top view, and a front view of the electric actuator 200, respectively. Figure 15 is a diagram showing the configuration of the crankshaft 270 of the electric actuator 200.

[0077] The electric actuator 200 according to the fourth embodiment of the present invention is a four-cylinder type actuator that mimics the structure of a four-cylinder engine, and comprises a crankshaft 270 and four drive units 200d connected to the crankshaft 270. In other words, the electric actuator 200 comprises four electric motors, four first motion transducers, and four second motion transducers, and as will be described later, the four second motion transducers 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 in Figure 16.

[0078] Each drive unit 200d has a structure similar to 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 Figure 11.

[0079] As shown in Figure 12, the motor 10 is fixed to a frame 220 that houses the shaft coupling 20, and the frame 220 is fixed on a base 210. The output shaft of the motor 10 is connected by the shaft coupling 20 to the shaft of a ball screw 40 supported by a bearing 30 provided on the frame 220, as shown in Figure 13.

[0080] A piston 250 is fixed to the nut of the ball screw 40. As shown in Figure 12, the piston 250 is placed on a carriage 242 that is movable along a rail 241 which is arranged parallel to the axis of the ball screw 40 on the upper surface of the frame 230. By placing the piston 250 on the carriage 242 in this way, the linear motion of the piston 250 is guided by the rail 241 and the carriage 242. This prevents excessive bending stress from being applied perpendicular to the ball screw 40 when the piston 250 performs reciprocating linear motion.

[0081] As shown in Figures 12 and 13, the end 251 of the piston 250 is rotatably connected to one end (clevis portion) of the connecting rod 260 by a pin 252 (first pin). This allows the connecting rod 260 to pivot within a certain angular range with respect to the pin 252 as the reciprocating linear motion of the piston 250. The other end of the connecting rod 260 is rotatably connected to the crankshaft 270 by a crank pin 273, as shown in Figures 13 and 14.

[0082] The crankshaft 270 is a rotating body and has a structure that mimics a crankshaft for a four-cylinder engine. As shown in Figure 15, the crankshaft 270 consists of multiple parts, which are fixed to each other with bolts. With such a configuration, it is possible to easily construct a crankshaft that corresponds to any number of drive units d, not just a four-cylinder type.

[0083] Specifically, as shown in Figures 14 and 15, the crankshaft 270 includes crank journals (crank journal 271, crank journal 272) supported by bearings provided on bearing sections (bearing section 281, bearing section 282) erected from 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 an eccentric position with respect to the axis of the crank journal. The crank pin 273 is an eccentric pin that is eccentric with respect to the rotation axis of the crankshaft 270.

[0084] Each of the crank journals 271 and 272 and the crank pin 273 is bolted to the crank arm 274, and furthermore, the crank journals 271 and 272 and the crank pin 273 are connected via the crank arm 274.

[0085] The crankshaft 270 includes two types of crank journals: a crank journal 271 with an output shaft and a crank journal 272 sandwiched between the crank arms 274. The crank journal 272 sandwiched between the crank arms 274 is composed of two parts (crank journal 272a and crank journal 272b) in order to be inserted into the bearing. One part (crank journal 272a) is inserted into the bearing, and then the other part (crank journal 272b) is fixed together with a bolt.

[0086] 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 constitute a slider-crank mechanism, thereby converting the reciprocating linear motion of the piston 250 into the unidirectional rotational motion of the crankshaft 270. In other words, the electric actuator 200 is configured to convert the reciprocating rotational motion of the motor 10 into unidirectional rotational motion and output it, similar to the electric actuator 200 of the first embodiment.

[0087] 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 crankpins 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 their respective crank mechanisms, so that the power generated by the four drive units 200d is coupled at the crankshaft 270. This is another point in which the electric actuator 200 differs from the electric actuator 100.

[0088] The eccentricity directions of the four crankpins 273 included in the crankshaft 270 are not particularly limited, but may be different from each other. For example, the eccentricity directions of the four crankpins 273 may be alternately differed by 180° each. Alternatively, the eccentricity directions of the four crankpins 273 may be differed by 90° each, for example, so that the timing of when the four crankpins 273 reach dead center does not coincide. This eliminates the time when no rotational force acts on the crankshaft 270, thereby achieving smooth rotation.

[0089] Figure 16 is a block diagram showing the schematic configuration of the power supply system 290S (electric drive system 290) of the electric actuator 200 according to the fourth embodiment of the present invention. The power supply system 290S, together with four drive units 200d (specifically, motors 10), constitutes the electric drive system 290.

[0090] The electric drive system 290 and power supply system 290S of the fourth embodiment differ from the first embodiment in that they are equipped with a plug 291 that is plugged into a primary power outlet (not shown), and in the configuration of the servo amplifier. The servo amplifier 295 of the fourth embodiment is equipped with a battery 295e and four inverters 95b, each corresponding to one of the four drive units 200d. The electric actuator 200 of the fourth embodiment can operate using the power stored in the battery 295e even when disconnected from the primary power supply, thanks to the inclusion of the battery 295e. The battery 295e is connected in parallel with the power regeneration converter 95a and the four inverters 95b to a DC bus 95d consisting of a pair of conductors. Each inverter 95b is connected to the motor 10 of the corresponding drive unit 200d.

[0091] The four inverters 95b are connected in parallel to a common DC bus 95d. That is, the DC power generated by the power regeneration converter 95a, battery 295e, and capacitor 95c is distributed to the four inverters 95b. The regenerative power output from the four inverters 95b is coupled at the DC bus 95d. A portion of the regenerative power returned to the DC bus 95d is again distributed to the four inverters 95b. Any surplus regenerative power is stored in the capacitor 95c and battery 295e, or returned to the primary power source via the power regeneration converter 95a.

[0092] Furthermore, if the eccentricity direction of the four crankpins 273 is changed by 90° each (i.e., the eccentricity directions of the four crankpins 273 are 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock), the motors 10 of the two drive units 200d connected to the crankpins 273 eccentric at 12 o'clock and 6 o'clock on the crankshaft 270, and the motors 10 of the remaining two drive units 200d connected to the crankpins 273 eccentric at 3 o'clock and 9 o'clock, have opposing timings for consuming / regenerating power. As a result, most of the regenerated power output from the motors 10 of one set of drive units 200d is efficiently consumed by the motors 10 of the other set of drive units 200d. Therefore, it becomes possible to drive the electric actuator 200 with lower power consumption.

[0093] <Fifth Embodiment> Figure 17 is a perspective view of the electric actuator 201 according to the fifth embodiment of the present invention. Figure 18 is a plan view of the electric actuator 201.

[0094] As shown in Figure 17, the electric actuator 201 according to the fifth embodiment of the present invention comprises 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 a detailed description is omitted. In other words, the electric actuator 201 comprises two electric motors, two first motion transducers, and two second motion transducers, and the two second motion transducers share an output shaft for unidirectional rotational motion. The electric actuator 201 may also include a servo amplifier 295 (drive device) and a control device 296, similar to the electric actuator 200.

[0095] The crankshaft 270a has a structure that mimics a crankshaft for a two-cylinder engine. Similar to the crankshaft 270 of the fifth embodiment, the crankshaft 270a is composed of multiple parts, which are fastened together with bolts.

[0096] Specifically, as shown in Figure 18, the crankshaft 270a comprises crank journals (crank journal 271, crank journal 272) supported by bearings provided on bearing sections (bearing section 281, bearing section 282) erected from 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 an eccentric position with respect to the axis of the crank journal. The difference between the crankshaft 270a and the crankshaft 270a is that the number of parts is fewer than that of the crankshaft 270 due to the reduction in the number of cylinders (number of drive units). For example, there is only one crank journal 272 between cylinders, and only two crank pins 273 per cylinder.

[0097] 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 a second motion converter to convert reciprocating motion (reciprocating linear motion) into unidirectional rotational motion. However, the present invention is not limited to this configuration. Embodiments that do not use a crankshaft will be described below.

[0098] <Sixth Embodiment> Figure 19 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 comprises a base 304, a drive unit 300d and a spindle section 370 installed on the base 304. The electric actuator 300 may also include a servo amplifier and a control device (not shown), similar to the electric actuator according to the above-described embodiment.

[0099] The drive unit 300d comprises 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 the screw shaft 41 of the ball screw 40, a box-shaped linear motion section 350 (hereinafter referred to as "piston 350") that is movable in the axial direction (i.e., in the extension direction of axis Ax1), a guideway-type circulating linear bearing 354 (hereinafter referred to as "linear guide 354") that movably supports the piston 350 in the axial direction, a connecting rod 360 that connects the piston 350 and the spindle 372 of the spindle section 370 (described later), and frames 305 and 306 mounted on the base 304. The motor 10 and bearing 30 are mounted on the frame 305. In this embodiment, the axis Ax1 of the drive unit 300d is a straight line common to the centerlines of the shaft 11 of the motor 10 and the screw shaft 41 of the ball screw 40.

[0100] The linear guide 354 comprises a rail 354a and a carriage 354b that can travel on the rail 354a. The rail 354a is mounted on the upper surface of the frame 306, and the carriage 354b is mounted on 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.

[0101] The shaft 11 (not shown) of the motor 10 is connected to the screw shaft 41 of the ball screw 40 by a shaft coupling 20. The nut 42 (not shown) of the ball screw 40 is housed in the hollow part of the piston 350 and fixed to the piston 350. As the 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.

[0102] The spindle section 370 comprises a rotating spindle 372 and a bearing section 374 that rotatably supports the spindle 372. A pin 372p is eccentrically mounted on one end face of the spindle 372. That is, the pin 372p is an eccentric pin that is offset from the rotation axis of the spindle 372.

[0103] Ball joints 362 are provided at both ends of the connecting rod 360 in this embodiment. One ball joint 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. Rolling bearings such as self-aligning roller bearings or self-aligning ball bearings may be used instead of the ball joints 362.

[0104] The motor 10 is driven so that the shaft 11 repeatedly reciprocates 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 reciprocates linearly along the axis Ax1 with a predetermined stroke. That is, the ball screw 40 functions as a first motion transducer 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. That is, the connecting rod 360 and the spindle 372 constitute a link mechanism that acts as a second motion transducer that converts reciprocating motion (reciprocating linear motion) into unidirectional rotational motion.

[0105] <Seventh Embodiment> Figure 20 is an external view of an electric actuator 400 according to the seventh embodiment of the present invention. The electric actuator 400 of this embodiment comprises two drive units 400d arranged side by side and a gear unit 470 connected to the two drive units 400d. The electric actuator 400 may include a servo amplifier and a control device (not shown), similar to the electric actuator according to the above-described embodiment. Note that the drive unit 400d of this embodiment differs in configuration from the drive unit 300d of the sixth embodiment in that the frames 405 of the two drive units 400d are integrated, but other configurations are common to the drive unit 300d.

[0106] Figure 21 shows the mechanism of the gear unit 470. The connecting rod 360 of the drive unit 300d is also shown in Figure 21.

[0107] The gear unit 470 comprises a case 471 (Figure 20), two pairs of bearings 473 and 476 mounted on the case 471, a first shaft 472 (input shaft) rotatably supported by a pair of bearings 473, a drive gear 474 mounted on the first shaft 472, a second shaft 475 (output shaft) rotatably supported by a pair of bearings 476, and a driven gear 477 mounted on 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.

[0108] Disc portions 472a are provided at both ends of the first shaft 472. Pins 472p are eccentrically attached to each disc portion 472a. In this embodiment, the eccentric directions of the pins 472p of the two disc portions 472a are offset by 90 degrees.

[0109] The connecting rod 360 of one drive unit 400d is connected to a pin 472p on one disc portion 472a of the first shaft 472, and the connecting rod 360 of the other drive unit 400d is connected to a pin 472p on the other disc portion 472a of the first shaft 472. Therefore, the power output from the pair of drive units 400d is combined in the gear unit 470 (more specifically, the first shaft 472) and output from the second shaft 475.

[0110] In this embodiment, the eccentricity of the pins 472p of the two disc portions 472a that connect to the connecting rod 360 of the two drive units 400d is offset by 90 degrees. As a result, the motors 10 of the two drive units 400d have opposing timings for consuming and regenerating power, so that most of the regenerative power output from the motor 10 of one drive unit 400d is efficiently consumed by the motor 10 of the other drive unit 400d. Consequently, it is possible to drive the electric actuator 400 with lower power consumption.

[0111] In the first to seventh embodiments described above, a configuration is employed in which reciprocating rotational motion is first converted to reciprocating linear motion by a first motion converter, and then further converted to unidirectional rotational motion by a second motion converter. However, the present invention is not limited to this configuration, and a configuration in which reciprocating rotational motion is directly converted to unidirectional rotational motion, as in the eighth embodiment of the present invention described below, is also included in the scope of the present invention.

[0112] <Eighth Embodiment> Figure 22 is an external view of an electric actuator 500 according to the eighth embodiment of the present invention. The electric actuator 500 of this embodiment comprises a base 504, a drive unit 500d and a spindle section 570 installed on the base 504. The electric actuator 500 may also include a servo amplifier 95 and a control device 96 as shown in Figure 23. The drive unit 500d comprises a motor 10, a drive disk 550 (first disc section) coupled to the shaft 11 of the motor 10, and a connecting rod 560. A pin 552 (first pin) is eccentrically attached to the drive disk 550.

[0113] The spindle portion 570 comprises a spindle 572 and a bearing portion 574 that rotatably supports the spindle 572. The spindle 572 comprises a cylindrical shaft portion 572b, a driven disk 572a (second disc portion) coupled to one end of the shaft portion 572b, and a pin 572p (second pin) eccentrically attached to the driven disk 572a.

[0114] Ball joints 562 are provided at both ends of the connecting rod 560. One ball joint 562 is connected to the drive disk 550 via a pin 552, allowing it to rotate around the pin 552. The other ball joint 562 is connected to the driven disk 572a (spindle 572) via a pin 572p, allowing it to rotate around the pin 572p. In other words, the connecting rod 560 is connected to the drive 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.

[0115] The motor 10 is driven so that the shaft 11 (and drive disk 550) repeatedly reciprocates within a predetermined angular range. This causes the connecting rod 560 to repeatedly push and pull in the longitudinal direction over a predetermined stroke, resulting in the driven disk 572a (spindle 572) rotating continuously in one direction. In other words, the reciprocating rotational motion of the motor 10 is converted into unidirectional rotational motion of the spindle 572 by a link mechanism consisting of the drive disk 550, the connecting rod 560, and the driven disk 572a. This link mechanism can also be interpreted as a combination of two crank mechanisms (specifically, a first crank mechanism as a first motion transducer consisting of the drive disk 550 and the connecting rod 560, and a second crank mechanism as a second motion transducer consisting of the connecting rod 560 and the driven disk 572a).

[0116] Furthermore, the spindle portion 570 (more specifically, the bearing portion 574) of this embodiment incorporates a generator 80 (Figure 23).

[0117] Figure 23 is a block diagram showing the schematic configuration of the power supply system 590S (electric drive system 590) of the electric actuator 500 according to the eighth embodiment of the present invention. The power supply system 590S, together with the motor 10, constitutes the electric drive system 590.

[0118] The electric drive system 590 and power supply system 590S of the eighth embodiment differ from the electric drive system 90 and power supply system 90S of the first embodiment in that they include a generator 80 and an inverter device 97 that converts the power generated by the generator 80 into grid power (e.g., three-phase alternating current) and supplies it to the primary power source. The inverter device 97 is connected to the control device 96 in a communicative manner and operates according to the control of the control device 96.

[0119] The inverter device 97 comprises a converter 97a, an inverter 97b, and a capacitor 97c. The converter 97a includes a full-wave rectifier, for example, 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 a PWM inverter that controls the output power by PWM control, for example.

[0120] The power generated by the generator 80 is converted to DC by the converter 97a, smoothed by the capacitor 97c, and then input to the inverter 97b. A single DC bus 97d is formed from a pair of positive and negative conductors. The inverter 97b converts the DC power supplied from the DC bus 97d into a sinusoidal AC of equivalent quality to grid power and outputs it to the primary power supply 91.

[0121] According to the configuration of this embodiment, electricity is generated by the generator 80 not only during regenerative operation but also during power operation, and power is supplied to the primary power source 91, so electrical energy can be utilized more efficiently.

[0122] 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 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. Furthermore, a portion of the power may be branched from the rotating shaft of the drive unit 500d or the spindle portion 570 and transmitted to the generator 80 by a belt, chain, or other winding transmission or gear mechanism.

[0123] In this embodiment, the generator 80 is an AC generator, but a DC generator may also be used. In this case, since rectification of the power generated by the generator is unnecessary, the converter 97a of the inverter device 97 is not required, and for example, the output terminal of the DC generator is connected to the DC bus 97d without going through the converter 97a.

[0124] Alternatively, the inverter device 97 may be equipped with a battery, and the battery may be connected in parallel with the capacitor 97c to the DC bus 97d.

[0125] Alternatively, a clutch may be provided between the generator 80 and the motor 10, and the timing of power absorption by the generator 80 may be controlled by the engagement and disengagement of the clutch.

[0126] Furthermore, the DC bus 97d, capacitor 97c, and inverter 97b of the inverter device 97 may be shared with the DC bus 95d, capacitor 95c, and power regeneration converter 95a of the servo amplifier 95, respectively.

[0127] Next, we will describe some application examples of the electric actuator according to the embodiment of the present invention.

[0128] <Ninth Embodiment> Figure 24 is a schematic diagram showing the power system configuration of an electric vehicle 1 equipped with an electric actuator 200 according to the fourth embodiment of the present invention as a prime mover. The electric vehicle 1 comprises a power transmission device 2 and left and right drive shafts 3a and 3b. The power transmission device 2 comprises a transmission, a final reduction gear, and a differential (not shown). The crankshaft 270 of the electric actuator 200 is connected to the input shaft of the power transmission device 2. The drive shafts 3a and 3b are connected to the left and right output shafts of the power transmission device 2, respectively. Wheels W are attached to the ends of each drive shaft 3a and 3b. The power output from the electric actuator 200 is transmitted to the drive shafts 3a and 3b via the transmission, final reduction gear, and differential of the power transmission device 2, and rotates the wheels W attached to the ends of the drive shafts 3a and 3b.

[0129] The electric actuator according to the embodiment of the present invention can be used to replace various prime movers that output rotational motion (for example, engines, electric motors, hydraulic motors, air motors, steam turbines, etc.).

[0130] The application example shown in Figure 24 is an example of applying the electric actuator according to an embodiment of the present invention to a four-wheeled electric vehicle. However, the electric actuator according to an embodiment of the present invention can be used in various vehicles such as two-wheeled vehicles, three-wheeled vehicles, or trucks, buses, and tractors with six or more wheels. Furthermore, the electric actuator according to an embodiment of the present invention can be used not only in electric vehicles but also in hybrid vehicles.

[0131] Furthermore, the electric actuator according to the embodiment of the present invention can be used not only in automobiles but also as a prime mover for railway vehicles.

[0132] <Tenth Embodiment> The tenth embodiment, which will be described next, is an example of applying the present invention to a railway system. Figure 25 is a diagram showing the schematic configuration of the drive mechanism of a railway vehicle 600 according to the 10th embodiment of the present invention. The railway vehicle 600 is equipped with a plurality of (three in the example shown in Figure 25) bogies 601. The bogies 601 are powered bogies equipped with an electric actuator 200 according to the 4th embodiment of the present invention as a drive device.

[0133] The bogie 601 comprises two electric actuators 200, each with two pairs of axles 603 (axles 603a and 603b), bearings 602, axle boxes (not shown), axle box support devices (not shown), and wheels 604. One end of axles 603a and 603b are connected to both ends of the crankshaft 270 of the electric actuators 200. Wheels 604 are attached to the other ends of axles 603a and 603b.

[0134] Each bearing 602 is mounted to each axle box, and each axle box is mounted to the bogie frame 605 via each axle box support device. The bearings 602 and axle boxes are cushioned and supported against the bogie frame 605 (frame) by the axle box support devices. Each axle 603a and 603b is rotatably supported by each bearing 602.

[0135] Figure 26 is a block diagram showing the schematic configuration of the power supply system 690S (electric drive system 690) of a railway vehicle 600 according to the 10th embodiment of the present invention. The power supply system 690S, together with a plurality of electric actuators 200 (specifically, a plurality of motors 10) mounted on the railway vehicle 600, constitutes the electric drive system 690.

[0136] Railway vehicle 600 is a powered vehicle that collects power using an overhead line current collection system, equipped with a pantograph 692c that contacts the overhead line 691b, which is a trolley wire (contact wire). The overhead line 691b is supplied with grid power (e.g., three-phase AC) from the substation 691a.

[0137] Of the electric drive system 690 (power supply system 690S), the mobile drive system 690M (mobile power supply system 690MS) mounted on the railway vehicle 600 consists of one or more mobile drive units 690MU (mobile power supply system 690MSU) unitized for each corresponding bogie 601. Note that the mobile drive units 690MU (mobile power supply system 690MSU) may be configured not on a bogie 601 basis, but on a railway vehicle 600 basis, or on a train basis formed by connecting multiple railway vehicles 600.

[0138] According to the electric drive system 690 of the 10th embodiment of the present invention, the same effects and advantages as the electric drive system 290 of the second embodiment of the present invention can be obtained. That is, since 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.

[0139] In this embodiment, an overhead catenary current collection system is employed using the pantograph 692c as the current collector. However, other types of current collectors (e.g., bow collectors, trolley poles, etc.) or other types of current collection systems (e.g., a third rail system in which current is collected by contacting the current collector shoe with the power supply rail [third rail]) may also be used.

[0140] The railway vehicle 600 in this embodiment is a bogie-type vehicle that uses a bogie 601 as its running gear, and a 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 gear and the mobile body drive unit 690MU may be directly mounted on the vehicle body.

[0141] In this embodiment, each bogie 601's mobile drive unit 690MU (specifically, the servo amplifier 695) is equipped with a battery 295e, but the battery 295e may be shared among the mobile drive units 690MU of multiple bogies 601. In this case, for example, the battery 295e may be provided only in the servo amplifier 695 of one (or some) of the multiple bogies 601, and the DC bus 95d of the multiple bogies 601 may be connected. Alternatively, the battery 295e may be placed outside the servo amplifier 695 (for example, on the vehicle body) and connected to the DC bus 95d of the multiple bogies 601.

[0142] In this embodiment, a configuration is adopted in which the split axles 603a and 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, the electric actuator 200 and the unsplit axle 603 may be connected via a power transmission device such as a gear device.

[0143] In this embodiment, a shaft box support system using a shaft box and a shaft box support device is employed, but the present invention is not limited to this configuration.

[0144] <Embodiment 11> Next, an example of applying the present invention to a tire testing apparatus will be described. The tire testing apparatus according to the 11th embodiment of the present invention, described below, is a testing apparatus capable of performing tire wear tests, durability tests, driving stability tests, and the like.

[0145] Figures 27 and 28 are perspective views of the tire testing apparatus 2000 according to the 11th embodiment of the present invention, viewed from different directions. The tire testing apparatus 2000 of this embodiment includes a rotating drum 2010 with a simulated road surface formed on its outer circumference, an alignment adjustment mechanism 2160 that rotatably holds a tire T in contact with the simulated road surface in a predetermined position, 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.

[0146] 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 shaft of the rotating drum 2010. 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. Pulley 2012c is connected to pulley 2012d by a drive belt 2016. Pulley 2012d is fixed coaxially to pulley 2012e and is rotatably supported together with pulley 2012e by a bearing 2011c (Figure 28). Furthermore, the pulley 2012e is connected to the shaft portion 131a of the casing 131 of the torque generating device 130, which will be described later, by the drive belt 2017.

[0147] Figure 29 shows the internal structure of the torque generator 130. The torque generator 130 comprises a casing 131 and a servo motor 10 and a reduction gear 133 fixed inside the casing 131. In this embodiment, the servo motor 10 has the same configuration as in the first embodiment. Cylindrical shaft portions 131a and 131b are formed at both axial ends of the casing 131. The casing 131 is rotatably supported at the shaft portions 131a and 131b by bearing portions 2020 and 2030. A pulley 2012f is attached to the outer circumference of the shaft portion 131a at one end (the right end in Figure 29).

[0148] The reduction gear 133 has an input shaft 133a and an output shaft 133b, and reduces the rotational motion input to the input shaft 133a before outputting it to the output shaft 133b. The input shaft 133a of the reduction gear 133 is connected to the drive shaft 150a of the servo motor 10 by a coupling 134. A connecting shaft 135 is connected to the output shaft 133b of the reduction gear 133. The reduction gear 133 is optionally provided in the torque generator 130. Alternatively, the torque generator 130 may not have a reduction gear 133, and the connecting shaft 135 may be directly connected to the drive shaft 150a of the servo motor 10.

[0149] The connecting shaft 135 passes 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 circumference 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 (Figure 27). A wheel with a tire T mounted on it is attached to the spindle of the alignment adjustment mechanism 2160.

[0150] As a result, when the inverter motor 2080 is driven, the rotating drum 2010 rotates, and the casing 131 of the torque generator 130, which is connected to the inverter motor 2080 via the rotating drum 2010, also rotates. Furthermore, when the torque generator 130 is not operating, the rotating drum 2010 and the tire T rotate in opposite directions so that their peripheral speeds at the contact point are the same. In addition, by operating the torque generator 130, dynamic or static driving force and braking force can be applied to the tire T.

[0151] In this embodiment, the power output from the inverter motor 2080 is transmitted back to the rotating drum 2010 via the rotating drum 2010, the intermediate shaft 2013, the torque generator 130, the constant velocity joint 2014, the spindle of the alignment adjustment mechanism 2160, and the tire T. In other words, the power transmission path consisting of the rotating drum 2010, the intermediate shaft 2013, the torque generator 130, the constant velocity joint 2014, the spindle of the alignment adjustment mechanism 2160, and the tire T constitutes a power circulation system. As a result, the power of the inverter motor 2080 is utilized efficiently, enabling operation with low power consumption.

[0152] The alignment adjustment mechanism 2160 of this embodiment is a mechanism that rotatably supports the tire T, which is a test specimen, while it is 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 relative to the simulated road surface and the tire load (ground pressure) to a set state. 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 relative to the simulated road surface by tilting the rotation axis of the tire T around a 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 rotation axis direction. The tire load adjustment unit 2161, slip angle adjustment unit 2162, camber angle adjustment unit 2163, and traverse device 2164 are each equipped with servo motors M1, M2, M3, and M4, respectively. The servo motors M1, M2, M3, and M4 are, for example, AC servo motors.

[0153] Figure 30 is a block diagram showing the schematic configuration of a power supply system 2800S (electric drive system 2800) according to a second embodiment of the present invention, which supplies power to a servo motor 10 and an inverter motor 2080.

[0154] The power supply system 2800S of this embodiment differs from the power supply system 90S of the first embodiment in that it has a power supply system 2860 (reactor 2870, driver 2880) that supplies power to the inverter motor 2080 branched from the downstream 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 the driving power for the inverter motor 2080 and is equipped with an inverter circuit (not shown). The driver 2880 and servo amplifiers A1 to A4 are each connected to the control unit C2 in a communicative manner and operate according to the control of the control unit C2. Servo amplifiers A1, A2, A3, and A4 have the same configuration as servo amplifier 2850.

[0155] In a test using the tire testing apparatus 2000 of this embodiment, rotational motion is applied to the tire T by combining the rotational speed output by the inverter motor 2080 and the torque generated by the torque generator 130 (specifically, the servo motor 10). In an example of a test using the tire testing apparatus 2000, the inverter motor 2080 is controlled to output a constant rotational speed, and the servo motor 10 is controlled to output a fluctuating torque (for example, a random vibration torque). Specifically, the servo motor 10 is driven to reciprocate rotation while changing its amplitude and period based on predetermined vibration waveform data. That is, the control unit C2 controls the motor 10 to repeatedly rotate in the forward and reverse directions. As a result, acceleration and deceleration of the servo motor 10 are repeated, and the supply of drive power from the servo amplifier 2850 to the servo motor 10 and the supply of regenerative power from the servo motor 10 to the servo amplifier 2850 are repeated.

[0156] Most of the regenerative power generated by the servo motor 10 is temporarily stored in the capacitor 2853 and then used to drive the servo motor 10. Any surplus regenerative power is supplied to the power supply systems 2860, 2891, 2892, 2893, and 2894 via the power regeneration converter 2851 and the reactor 2840, and used to drive the inverter motor 2080 and the servo motors M1, M2, M3, and M4. As a result, almost all of the regenerative power generated by the servo motor 10 is reused to drive the servo motors 10, M1-M4, and the inverter motor 2080, and the power consumption of the primary power supply 2810 used to drive the servo motor 10 is slightly reduced. Furthermore, the regenerative power generated by the inverter motor 2080 and the servo motors M1, M2, M3, and M4 is reused to drive other motors (i.e., servo motors 10, M1, M2, M3, M4 and inverter motor 2080), further reducing the power consumption of the primary power supply 2810.

[0157] By setting a tire T in the tire testing apparatus 2000 with the configuration described above 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 servo motor 10 of the torque generating device 130 to apply driving force and braking force to the tire T, it becomes possible to perform tire wear tests, durability tests, driving stability tests, etc., that simulate actual driving conditions.

[0158] In this embodiment, an inverter motor 2080 was used to rotate the tire T and the rotating drum 2010 at the same peripheral speed. However, instead of the driver 2880 and inverter motor 2080 in Figure 30, an electric actuator 100 according to the first embodiment, which includes a servo motor 10 and a drive unit 100d, may be used. That is, instead of directly attaching the pulley 2012a to the output shaft of the servo motor 10, a drive unit 100d that converts the reciprocating rotation of the servo motor 10 into unidirectional rotation can be provided between the servo motor 10 and the pulley 2012a. This makes it possible to utilize regenerative energy even when rotating the tire T and the rotating drum 2010 at the same peripheral speed. <Twelfth Embodiment>

[0159] The combined testing apparatus according to the twelfth embodiment of the present invention, described below, is a testing apparatus capable of performing uniformity testing and dynamic balancing testing of tires. Figure 31 is a side view showing the basic configuration of the combined uniformity and dynamic balancing testing apparatus 3000 (hereinafter referred to as the combined testing apparatus 3000) according to an embodiment of the present invention. Figure 32 schematically shows a method for rotationally driving the spindle 3120 of the combined testing apparatus 3000.

[0160] As shown in Figure 31, the combined testing apparatus 3000 is configured to hold the tire T by sandwiching it between the lower rim 3010 and the upper rim 3020. More specifically, the combined testing apparatus 3000 holds the tire T by sandwiching it between the lower rim 3010 and the upper rim 3020 by inserting and fixing a lock shaft 3300, to which the upper rim 3020 is fixed at the upper end, into the spindle 3120.

[0161] In the uniformity test, a rotating drum 3030 is provided on the side of the spindle 3120. The rotating drum 3030 is mounted in a movable housing 3032 that slides on a rail 3031 extending in a direction toward / away from the tire T, and moves toward / away from the tire T by a rack and pinion mechanism 3035 (pinion 3036, rack 3038) driven by a motor (not shown). The rotating drum 3030 can also be rotated at any rotational speed by an electric actuator (not shown) (hereinafter referred to as electric actuator 100a). The configuration of electric actuator 100a is the same as that of electric actuator 100 described above in the first embodiment.

[0162] 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 then pressed against the tire T with a force of several hundred kgf or more. Next, the rotating drum 3030 is rotated in this state (and therefore the tire T in contact with the rotating drum 3030 also rotates with the rotating drum 3030), and the variation in the force generated on the rotating tire from the load fluctuations at that time is measured by a three-axis piezoelectric element installed on the side of the spindle housing 3110.

[0163] In this embodiment, the rotating drum 3030 is rotated using an electric actuator 100a. This allows the rotating drum 3030 to be rotated while utilizing regenerative energy, enabling uniformity testing.

[0164] On the other hand, the dynamic balancing test involves rotating the tire T together with the spindle 3120 while the rotating drum 3030 is separated from the tire T, and measuring the eccentricity of the tire from the excitation force generated due to the unbalance of the tire T at that time.

[0165] A pulley 3140 is attached to the lower end of the spindle 3120 for rotationally driving the spindle 3120 during the dynamic balancing test. Furthermore, an electric actuator 100b, which can move horizontally toward the spindle 3120 by a rack and pinion mechanism (not shown), is installed on the base 3050 to which the spindle 3120 is fixed. This electric actuator 100b rotates the spindle 3120. The configuration of the electric actuator 100b is the same as that of the electric actuator 100 described above in the first embodiment. This allows the spindle 3120 to be rotated while utilizing regenerative energy, enabling the dynamic balancing test to be performed.

[0166] A drive pulley 3144 is mounted on the output rotating shaft of the electric actuator 100b at the same height as the pulley 3140 of the spindle 3120. Also, as shown in Figure 32, 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 pulleys 3143 move back and forth together with the electric actuator 100b (drive pulley 3144) by a rack and pinion mechanism (not shown). An endless belt 3142 is stretched between the drive pulley 3144 and the driven pulley 3143, and the electric actuator 100b can advance the endless belt 3142 at a predetermined speed.

[0167] With the rack and pinion mechanism causing the endless belt 3142 to contact the pulley 3140 (as shown by the solid line in Figure 32), the electric actuator 100b is driven, causing the pulley 3140 to rotate and the spindle 3120 to rotate 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 three-axis piezoelectric element installed on the side of the spindle housing 3110.

[0168] 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.

[0169] In other words, the combined testing apparatus 3000 is equipped with two electric actuators 100a and 100b, the same as the electric actuator 100 of the first embodiment. Electric actuator 100a is used to rotate the rotating drum 3030, and electric actuator 100b is used to rotate the spindle 3120. This makes it possible to conduct tests while utilizing regenerative energy in both uniformity tests and dynamic balance tests.

[0170] <13th Embodiment> The balance measuring device 4000 according to the thirteenth embodiment of the present invention, described below, is a test device capable of measuring the balance of a rotating body. Figures 33 and 34 are a front view and a side view of the balance measuring device 4000 according to the embodiment of the present invention, respectively. In the following description, the vertical direction in Figure 33 is defined as the Y-axis direction, and the direction perpendicular to both the vertical direction and the rotation axis direction of the rotating body is defined as the X-axis direction. The rotating body 4100 in this embodiment is, for example, a crankshaft, and the balance measuring device 4000 is, for example, a device for measuring the balance of a crankshaft.

[0171] The balance measuring device frame of the balance measuring device 4000 consists of a base 4013, a plurality of springs 4014 extending vertically upward from the base 4013, and a table 4015 supported by these springs 4014. Drive shaft bearings 4012a and 4012b are mounted on the underside of the table 4015. The drive shaft 4005 is rotatably supported by these drive shaft bearings 4012a and 4012b. Also, as shown in Figure 34, a first side wall 4013a and a second side wall 4013b, which can be considered as substantially rigid bodies, extend vertically upward from both ends of the base 4013 in the X-axis direction.

[0172] An 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. On the other hand, a first pulley 4006 is attached to one end of the drive shaft 4005, and a first endless belt 4004 is passed 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 rotationally driven via the first endless belt 4004.

[0173] Furthermore, a first table side wall 4017a and a second table side wall 4017b are fixed to the top surface of the table 4015, perpendicular to each other and positioned vertically upward. The first table side wall 4017a and the second table side wall 4017b are rigid bodies with extremely high rigidity compared to the spring constant of the spring 4014. Driven shaft bearings 4016a and 4016c are fixed to the first table side wall 4017a, and driven shaft bearings 4016b and 4016d are fixed to the second table side wall 4017b. Note that only driven shaft bearings 4016a and 4016b are shown in Figure 33, and driven shaft bearings 4016c and 4016d are located behind the driven shaft bearings 4016a and 4016b in Figure 33. The driven shaft bearings 4016a, 4016b, 4016c, and 4016d rotatably support the driven shafts 4010a, 4010b, 4010c, and 4010d, respectively (only 4010a and 4010b are shown in Figure 33).

[0174] Pulleys 4009a, 4009b, 4009c, and 4009d are attached to one end of the driven shafts 4010a, 4010b, 4010c, and 4010d, respectively. Second pulleys 4007a and 4007b are attached to a location adjacent to pulley 4006 at one end of the drive shaft 4005 and to the other end of the drive shaft 4005. A second endless belt 4008a and 4008b are stretched across the second pulley 4007a, the pulley 4009a attached to the driven shaft 4010a, the pulley 4009c attached to the driven shaft 4010c, the second pulley 4007b, the pulley 4009b attached to the driven shaft 4010b, and the pulley 4009d attached to the 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. In addition, 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 rotate as well.

[0175] Rollers 4011a, 4011b, 4011c, and 4011d are attached to the other ends of the driven shafts 4010a, 4010b, 4010c, and 4010d, respectively. One end 4110a of the rotation axis of the rotating body 4100 is placed on rollers 4011a and 4011c, and the other end 4110b of the rotation axis of the rotating body 4100 is placed on rollers 4011b and 4011d. The rotating body 4100 rotates in response to the rotation of these rollers 4011a, 4011b, 4011c, and 4011d. In other words, the rotating body 4100 can be rotated while utilizing regenerative energy by driving the electric actuator 100.

[0176] A keyway 4102 is formed at the other end 4110b of the rotating body 4100. Furthermore, the balance measuring device 4000 is equipped with a sensor S for detecting the keyway 4102.

[0177] Furthermore, as shown in Figures 33 and 34, vibration pickups VDL and VDR are mounted between the first side wall 4013a of the base 4013 and the table 4015. The rotating body 4100, which is a crankshaft with dynamic unbalance, 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 the rollers 4011a, 4011b, 4011c, 4011d, the first and second table side walls 4017a, 4017b, etc. The vibration pickups VDL and VDR detect the vibrations transmitted from the rotating body 4100 (crankshaft) to the table 4015. In other words, the vibration pickups VDL and VDR detect fluctuations in the load that the rotating body 4100 (crankshaft) applies to the rollers 4011a, 4011b, 4011c, and 4011d.

[0178] The vibration pickups VDL and VDR are acceleration sensors capable of measuring two components (X-axis and Y-axis directions) of acceleration perpendicular to the rotation axis of the rotating body 4100. The vibration pickup VDL is mounted on the same XY plane as the first table side wall 4017a, and the vibration pickup VDR is mounted on the same XY plane as the second table side wall 4017b.

[0179] Furthermore, piezoelectric actuators VL and VR are mounted between the second side wall 4013b of the base 4013 and the table 4015. Piezoelectric actuator VL is mounted on the same XY plane as the first table side wall 4017a, and piezoelectric actuator VR is mounted on the same XY plane as the second table side wall 4017b. Piezoelectric actuators are components that expand and contract in accordance with the magnitude of the applied voltage, thereby displacing the object they come into contact with. Therefore, by controlling the signals input to piezoelectric actuators VL and VR, the table 4015 can be freely vibrated.

[0180] <Embodiment 14> Figure 35 is a perspective view of a collision simulation test apparatus 5000 according to the 14th embodiment of the present invention. The collision simulation test apparatus 5000 is a device that reproduces the impact applied to automobiles, occupants, equipment, etc., during a collision between automobiles, etc. (including railway vehicles, aircraft, and ships). The collision simulation test apparatus 5000 of this embodiment can also be used as an impact test apparatus to evaluate the durability and reliability against impact by applying strong shock waves to products and parts.

[0181] The crash simulation test device 5000 is equipped with a table 5240 that resembles the frame of an automobile vehicle. Test specimens, such as a seat with a dummy occupant or a high-voltage battery for an electric vehicle, are attached to the table 5240. When the table 5240 is driven with a set acceleration (for example, an acceleration equivalent to the impact applied to the vehicle frame during a collision), the test specimens attached to the table 5240 are subjected to an impact similar to that of an actual collision. The safety of the occupants is evaluated based on the damage sustained by the test specimens at this time (or the damage predicted from the measurement results of acceleration sensors attached to the test specimens).

[0182] The crash simulation test apparatus 5000 of this embodiment is configured to allow the table 5240 to be driven in only one direction, horizontally. As shown in the coordinate axes in Figure 35, the direction of movement of the table 5240 is defined as the X-axis direction, the horizontal direction perpendicular to the X-axis direction is defined as the Y-axis direction, and the vertical direction is defined as the Z-axis direction. Furthermore, with reference to the direction of travel of the vehicle being simulated, the positive X-axis direction is called forward, the negative X-axis direction is called backward, the negative Y-axis direction is called to the right, and the positive Y-axis direction is called to the left. The X-axis direction in which the table 5240 is driven is called the "driving direction". In a crash simulation test, a large acceleration is applied to the table 5240 in the opposite direction to the direction of travel of the vehicle (i.e., backward).

[0183] The collision simulation test apparatus 5000 includes a test section 5200 equipped with a table 5240, a forward drive unit 5300 and a rear drive unit 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 unit 5300, 5400 into translational motion in the X-axis direction and transmit it to the table 5240, and a control system (not shown).

[0184] The test section 5200 is located in the center of the collision simulation test device 5000 in the X-axis direction, and the forward drive unit 5300 and the rear drive unit 5400 are located adjacent to the front and rear of the test section 5200, respectively.

[0185] Figure 36 is a perspective view showing the structure of the test section 5200 and the belt mechanism 5100. For the sake of clarity, the table 5240 and the base block 5210 (described later), which are components of the test section 5200, are omitted from Figure 36.

[0186] The test section 5200 includes, in addition to the table 5240, a base block 5210 (Figure 35), a frame 5220 mounted on the base block 5210, and a pair of linear guideways 5230 (hereinafter abbreviated as "linear guides 5230") mounted on the frame 5220. The pair of linear guideways 5230 support the table 5240 so that it can move only in the X-axis direction (drive direction).

[0187] As shown in Figure 36, the frame 5220 has a pair of left and right half-frames (right frame 5220R, 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 of each other), only the left frame 5220L will be described in detail.

[0188] The left frame 5220L has a mounting portion 5221 and a rail support portion 5222 extending in the X-axis direction, and three connecting portions 5223 (5223a, 5223b, 5223c) extending in the Z-axis direction that connect the mounting portion 5221 and the rail support portion 5222. As shown in Figure 35, the length of the mounting 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 mounting portion 5221 and the rail support portion 5222 are connected by the connecting portion 5223a.

[0189] The rail support portion 5222 is longer than the mounting portion 5221 (i.e., longer than the base block 5210), and its tip protrudes forward of the base block 5210, positioned above the forward drive portion 5300.

[0190] The linear guide 5230 comprises 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 sections 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 section 5222, and the entire length of the rail 5231 is supported by the rail support section 5222. Multiple mounting holes (screw holes) are provided on the upper surface of the carriages 5232, and multiple through holes are provided in the table 5240 corresponding to the mounting holes of the carriages 5232. The carriages 5232 are fastened to the table 5240 by fitting bolts (not shown) passed through each through hole in the table 5240 into each mounting hole of the carriage 5232. The trolley (thread) is composed of a table 5240 and four carriages 5232.

[0191] Furthermore, the table 5240 has mounting structures such as screw holes for attaching test specimens (not shown), such as sheets, allowing the test specimens to be directly attached to the table 5240. This eliminates the need for mounting plates or other components for attaching the test specimens, thus reducing the weight of the movable parts to which impact is applied, and enabling the test specimen to receive impacts with high fidelity, even for high-frequency components.

[0192] As shown in Figure 36, 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 securing the toothed belt 5120 to the table 5240.

[0193] Four toothed belts 5120 are arranged parallel to each other between the right frame 5220R and the left frame 5220L. Each toothed belt 5120 is secured to the table 5240 at two points along its length by belt clamps 5180.

[0194] As shown in Figure 35, the forward drive unit 5300 comprises a base block 5310 and four electric actuators 5320 (5320a, 5320b, 5320c, 5320d) installed on the base block 5310. The rear drive unit 5400 also comprises a base block 5410 and four electric actuators 5420 (5420a, 5420b, 5420c, 5420d) installed on the base block 5410. The total of eight electric actuators each have the same configuration as the electric actuator 100 according to the first embodiment, and although there are slight differences in the installation position and orientation, the length of the components and the spacing between them, the basic configuration is the same. The basic configurations of the forward drive unit 5300 and the rear drive unit 5400 are also the same.

[0195] A control unit (not shown) can apply acceleration to the table 5240 according to the acceleration waveform by synchronously controlling the drive of the servo motors of each electric actuator 5320a-d and 5420a-d based on the input acceleration waveform. In this embodiment, the control unit drives all eight servo motors to reciprocate rotation in the same phase. This allows the table 5240 to be accelerated by outputting unidirectional rotational motion from each electric actuator while utilizing regenerative energy.

[0196] Furthermore, the electric actuator according to the embodiment of the present invention can be used as a replacement for various prime movers that output rotational motion (for example, engines, electric motors, hydraulic motors, air motors, steam turbines, etc.).

[0197] Furthermore, the electric actuator according to the embodiment of the present invention can be used not only in electric two-wheeled, three-wheeled, or four-wheeled vehicles, or in various electric vehicles such as trucks, buses, and tractors having six or more wheels, but also as a prime mover for railway vehicles. In other words, 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 (e.g., propeller planes) and helicopters, or for ships. In other words, the electric actuator according to the embodiment of the present invention can be used as a prime mover for any mobility.

[0198] Furthermore, the electric actuator according to the embodiment of the present invention can also be used as a prime mover for various industrial machines such as construction machinery, agricultural machinery, woodworking machinery, machine tools, forging and pressing machines, injection molding machines, robots, and transport machinery (e.g., cranes, elevators, conveyors, etc.).

[0199] 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.).

[0200] Furthermore, the electric actuator according to the embodiment of the present invention can also be used as a prime mover to drive a hydraulic pump or a compressor.

[0201] The above is a description of exemplary embodiments of the present invention. Embodiments of the present invention are not limited to those described above, and various modifications are possible within the scope of the technical idea of ​​the present invention. For example, embodiments of the present invention also include combinations of embodiments explicitly shown in the specification or obvious embodiments as appropriate.

[0202] In the aforementioned drive unit 100d, the screw shaft 41 of the ball screw 40 is directly connected to the shaft 11 of the motor 10. However, the drive unit may also be equipped with a reduction gear, and the motor 10 and the ball screw 40 may be connected via the reduction gear.

[0203] The electric drive system 90 (power supply system 90S) (Figure 5) of the first embodiment may also be configured to include a plug 291 and a battery 295e, similar to the fourth embodiment.

[0204] Alternatively, the plug 291 and battery 295e may be removed from the electric drive system 290 (power supply system 290S) (Figure 16) of the fourth embodiment, and the circuit breaker 92 may be directly connected to the primary power supply 91.

[0205] Alternatively, the circuit breaker 92, electromagnetic switch 93, and / or reactor 94 may be removed from the electric drive system 290 (power supply system 290S) (Figure 16) of the fourth embodiment and installed upstream of the plug 291 (on the primary power supply side).

[0206] Furthermore, in the electric drive system 90 (power supply system 90S) of the first embodiment (Figure 5), an AC generator may be used as the primary power source 91.

[0207] In the electric drive system 290 (power supply system 290S) of the fourth embodiment (Figure 16) or the electric drive system 690 (power supply system 690S) of the eleventh embodiment (Figure 26), 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 energy storage function of the battery 295e.

[0208] In the fourth embodiment of the electric drive system 290 (power supply system 290S) (Figure 16), a configuration is adopted in which a single servo amplifier 295 is connected to multiple inverters 95b, and each inverter 95b is connected to a motor 10 (i.e., a power regeneration converter 95a, a capacitor 95c, and a DC bus 95d are shared among multiple motors 10). However, the present invention is not limited to this configuration. For example, a configuration in which a servo amplifier 95 of the first embodiment (Figure 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 branched wiring. Alternatively, a reactor 94 may be provided for each servo amplifier 95, and the wiring is branched after the electromagnetic switch 93, with the reactor 94 and servo amplifier 95 connected to each branched wiring.

[0209] The electric actuator 100 according to the first embodiment of the present invention described above comprises a single drive unit 100d, the electric actuator 200 according to the fourth embodiment of the present invention comprises four drive units 200d, and the electric actuator 201 according to the fifth embodiment of the present invention comprises two drive units 200d. However, the present invention is not limited to these configurations, and any number of drive units can be provided in the electric actuator.

[0210] The electric actuators 100, 200, and 201 described above are equipped with a single crankshaft (crankshaft 70, crankshaft 270, crankshaft 270a), but they may be divided into multiple crankshafts. For example, if the electric actuator is equipped with four drive units, the crankshaft may be divided into two, and two drive units 100d may be 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, thus enabling miniaturization.

[0211] In the tire testing apparatus 2000 according to the 11th embodiment, the combined testing apparatus 3000 according to the 12th embodiment, the balance measuring apparatus 4000 according to the 13th embodiment, and the crash simulation testing apparatus 5000 according to the 14th embodiment, examples of the use of an electric actuator 100 are shown, but the electric actuators used in these apparatuses are not limited to the electric actuator 100 according to the first embodiment. For example, electric actuators of two cylinders or more, such as electric actuator 200 or electric actuator 201, may be used.

[0212] In each of the above embodiments, the motor 10 is an AC servo motor, but other types of electric motors capable of controlling the amount of drive (rotation angle), such as DC servo motors or stepping motors, may also be used as the motor 10.

[0213] In the fourth and tenth embodiments described above, a configuration in which a generator is included in the power supply system was illustrated. However, the generator is not limited to the fourth and tenth embodiments, and may be provided in the power supply system of other embodiments as well.

[0214] In each of the embodiments described above, a power regeneration converter 95a is used that can return excess regenerative power from the servo amplifier 95 to the primary power supply 91. However, a converter that does not have a power regeneration function to return excess power to the primary power supply 91 may also be used. When using a converter that does not have a power regeneration function, it is desirable to provide a device for storing excess power (for example, a large-capacity capacitor or a large-capacity battery) in the servo amplifier 95, rather than providing a regenerative resistor in the servo amplifier 95 to absorb regenerative power.

[0215] Figures 37 and 38 show modified examples of the power supply system that supplies power to the electric actuator according to each embodiment. In the above embodiments, a system that drives an electric motor by converting power supplied from a primary power source was illustrated, but the power supplied from the power source to the system is not limited to AC power. As shown in Figures 37 and 38, the motor 10 may also be driven by supplying DC power supplied from the battery 791 to the inverter via a converter. In this case, the regenerative power is stored in the battery 791 instead of being output to the primary power source.

[0216] The power supply system 790S (electric drive system 790) shown in Figure 37 is equipped with a bidirectional DC-DC converter 795a as a converter. First, the charger 792 is connected to the battery 791, and the battery 791 is charged by power supplied via the charger 792 from a plug 291 that is plugged into a primary power outlet (not shown). Next, the battery 791 is connected to the servo amplifier 795, and power from the battery 791 is supplied to the inverter 95b via the bidirectional DC-DC converter 795a to drive the motor 10, and regenerative power from the inverter 95b is output to the battery 791 via the bidirectional DC-DC converter 795a.

[0217] Furthermore, the power supply system 890S (electric drive system 890) shown in Figure 38 includes a bidirectional DC-AC converter 895a upstream of the power regeneration converter 95a. First, the charger 792 is connected to the battery 791, and the battery 791 is charged by power supplied via the charger 792 from a plug 291a that is plugged into a primary power outlet (not shown). Next, the battery 791 is connected to the servo amplifier 895, and power from the battery 791 is supplied to the inverter 95b via the bidirectional DC-AC converter 895a and the power regeneration converter 95a to drive the motor 10, and regenerative power from the inverter 95b is output to the battery 791 via the power regeneration converter 95a and the bidirectional DC-AC converter 895a. The power regeneration converter 95a and the bidirectional DC-AC converter 895a are connected to the plug 291b. Power from plug 291b, which is plugged into the primary power outlet (not shown), is supplied to inverter 95b via power regeneration converter 95a, and this power can also be used to drive motor 10. In addition, power supplied from plug 291b is supplied to battery 791 via bidirectional DC-AC converter 895a, and this power can also be used to charge battery 791.

[0218] In each of the embodiments described above, power was regenerated from the motor 10 to the primary power supply via the inverter 95b and the power regeneration converter 95a. However, power may also be regenerated from the motor 10 to the primary power supply without going through the inverter 95b and the power regeneration converter 95a.

[0219] This specification also describes the following inventions. [Note 1] Electric motor and, A drive device that supplies power to the electric motor, A control device capable of controlling the drive device so that the electric motor outputs a reciprocating rotational motion, A motion converter that converts the aforementioned reciprocating rotational motion into unidirectional rotational motion, Equipped with, The aforementioned drive device, A converter that converts AC power supplied from a power source into DC power, The system includes an inverter that generates drive power from the DC power, Electric actuator. [Note 2] The motion converter, A first disc portion connected to the shaft of the electric motor, A first pin is eccentrically mounted on the first disc portion, A second disc portion connected to the output shaft of the motion transducer, A second pin is eccentrically attached to the second disc portion, A connecting rod that connects the first disc portion and the second disc portion, Equipped with, One end of the connecting rod is rotatably connected to the first pin, The other end of the connecting rod is rotatably connected to the second pin. The electric actuator described in Appendix 1. [Note 3] The motion converter, A first motion converter that converts the aforementioned reciprocating rotational motion into reciprocating linear motion, A second motion converter that converts the aforementioned reciprocating linear motion into the aforementioned unidirectional rotational motion, including, The electric actuator described in Appendix 1. [Note 4] Electric motor and, A first motion converter that converts the rotational motion of the electric motor into linear motion, A second motion converter that converts the aforementioned linear motion into rotational motion, A drive device that supplies power to the electric motor, A control device for controlling the aforementioned drive device, Equipped with, The aforementioned drive device, A converter that converts AC power supplied from a power source into DC power, The system includes an inverter that generates drive power from the aforementioned DC power, The control device controls the electric motor to perform repeated reciprocating drives. Electric actuator. [Note 5] The first motion transducer is a ball screw, A linear motion section having a first pin fixed to the nut of the lead screw and moving linearly together with the nut, A crankshaft with an eccentric crankpin, A connecting rod rotatably connected to the first pin and the crank pin, Equipped with, The electric actuator described in Appendix 4. [Note 6] The aforementioned drive device, A DC bus consisting of a pair of conductors connecting the converter and the inverter, A capacitor connecting the pair of conductors, An electric actuator as described in any one of the items from Appendix 1 to Appendix 5. [Note 7] Equipped with multiple electric motors, The aforementioned drive device, A DC bus consisting of a pair of conductors connected to the converter, Multiple inverters connected to the aforementioned single DC bus, A capacitor connecting the pair of conductors, Equipped with, An electric actuator as described in any one of the items from Appendix 1 to Appendix 5. [Note 8] The aforementioned converter is a PWM converter. An electric actuator as described in any one of the items from Appendix 1 to Appendix 7. [Note 9] The control device controls the electric motor to perform reciprocating drives at a frequency of 3 Hz or higher. An electric actuator as described in any one of the items from Appendix 1 to Appendix 8. [Note 10] The system includes a generator that generates electricity using the power generated by the aforementioned electric motor, An electric actuator as described in any one of the items from Appendix 1 to Appendix 9. [Note 11] The system includes an inverter device that converts the power generated by the generator into AC power of equivalent quality to grid power and supplies it to the power source. The electric actuator described in Appendix 10. [Note 12] Wheels and, An electric actuator according to any one of the appendices 1 to 11 that outputs rotational motion to drive the aforementioned wheels, Equipped with, Electric vehicle. [Note 13] Wheels and, An electric actuator according to any one of the appendices 1 to 11 that outputs rotational motion to drive the aforementioned wheels, Equipped with, Railway vehicles. [Note 14] Equipped with a trolley, the trolley is The aforementioned wheels, The electric actuator and, Railway vehicles as described in Appendix 13. [Note 21] An electric motor that repeatedly rotates in forward and reverse directions at a desired frequency, The system includes a motion converter that converts the forward and reverse rotational motion output by the electric motor into unidirectional rotational motion. Electric actuator. [Note 22] The system further includes a drive unit that supplies power from a power source to the electric motor, The drive system includes a power regeneration converter that, when the motor repeatedly rotates in forward and reverse directions, regenerates power from the motor that was not consumed during acceleration back to the power supply. The electric actuator described in Appendix 21. [Note 23] The power regeneration converter outputs the power regenerated from the motor during the deceleration process when the motor is rotating in the forward direction and when it is rotating in the reverse direction to the power supply. The electric actuator described in Appendix 22. [Note 24] The power supply is composed of an AC power supply, The power regeneration converter is composed of a bidirectional AC-DC converter The electric actuator described in Supplementary Note 22. [Supplementary Note 25] The power supply is composed of a DC power supply, The power regeneration converter is composed of a bidirectional DC-DC converter The electric actuator described in Supplementary Note 22. [Supplementary Note 26] The drive device further includes a capacitor that stores the power that is not consumed by the acceleration of the electric motor among the power regenerated from the electric motor when the electric motor repeatedly rotates forward and backward. The electric actuator described in any one of Supplementary Notes 22 to 25. [Supplementary Note 27] The drive device further includes a drive device that supplies the power supplied from the power supply to the electric motor, The drive device includes a capacitor that stores the power that is not consumed by the acceleration of the electric motor among the power regenerated from the electric motor when the electric motor repeatedly rotates forward and backward. The electric actuator described in Supplementary Note 21. [Supplementary Note 28] The electric motor repeatedly rotates forward and backward at a required frequency of 3 Hz or more. The electric actuator described in any one of Supplementary Notes 22 to 27. [Supplementary Note 29] The motion converter is A first motion converter that converts the forward and reverse rotational motion into a reciprocating linear motion, A second motion converter that converts the reciprocating linear motion into the one-way rotational motion, and includes The electric actuator described in any one of Supplementary Notes 22 to 28. [Supplementary Note 30] A plurality of electric motors including the electric motor, A plurality of first motion converters that convert the forward and reverse rotational motions output by each of the plurality of electric motors including the first motion converter into a reciprocating linear motion, A plurality of second motion converters that convert the reciprocating linear motion converted by each of the plurality of first motion converters including the second motion converter into the one-way rotational motion, and further comprising: The plurality of second motion converters share an output shaft of the one-way rotational motion The electric actuator according to Supplementary Note 29. [Supplementary Note 31] The motion converter is a ball screw, a linear motion part fixed to a nut of the ball screw and linearly moving together with the nut, a rotating body rotatable around a rotation axis, a connecting rod rotatably connected to each of an eccentric portion of the rotating body with respect to the rotation axis and the linear motion part, including The electric actuator according to Supplementary Note 29. [Supplementary Note 32] The rotating body is a crankshaft, The connecting rod is rotatably connected to a crank pin of the crankshaft The electric actuator according to Supplementary Note 31. [Supplementary Note 33] The rotating body is a spindle, The connecting rod is rotatably connected to a protruding portion formed at a position eccentric with respect to the rotation axis of the spindle The electric actuator according to Supplementary Note 31. [Supplementary Note 34] Further comprising a control device for controlling the drive device, The control device controls the drive device so as to switch the rotation of the electric motor between forward rotation and reverse rotation while avoiding the timing at which 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. The electric actuator according to any one of Supplementary Notes 31 to 33. [Supplementary Note 35] Further comprising a control device for controlling the drive device, The control device controls the drive device such that the torque of the electric motor is limited at least when the linear motion part reaches a dead point where no rotational force is generated in the rotating body by the movement of the linear motion part. An electric actuator as described in any of the appendices 31 to 33. [Note 36] The motion converter, A first disc portion, which is rotatable around a first rotation axis and connected to the shaft of the electric motor, A second disc portion, which is rotatable around a second rotation axis, is connected to the output shaft of the motion transducer, The present invention includes a connecting rod rotatably connected to a portion of the first disc that is eccentric with respect to the first axis of rotation and to a portion of the second disc that is eccentric with respect to the second axis of rotation. An electric actuator as described in any of the appendices 31 to 38. [Note 37] An electric mobility device equipped with an electric actuator as described in any of the appendices 31 to 36. [Explanation of Symbols]

[0220] 1. Electric vehicle 10 motors 40 Ball screw 50, 250, 350 pistons (linear motion section) 60, 135, 260, 360, 560 connecting rod 70, 270, 270a crankshaft 80 Generators 95, 295, 695, 795, 895, 995, 2850 servo amplifier 95a, 2851 Power regeneration converter 95b, 97b, 2852 Inverter 95c, 97c, 2853 Capacitors 96, 296, C2 Control device (control unit) 100, 200, 201, 300, 400, 500, 5320, 5320a, 5420 Electric Actuators 100d, 200d, 300d, 400d, 500d drive unit 600 railway vehicles

Claims

1. Electric motor and, A drive device that drives the electric motor to output a first rotational motion using the power stored in the capacitor, A motion converter connected to the electric motor, which converts the first rotational motion into a second rotational motion, Equipped with, The first rotational motion is the forward and reverse rotational motion output from the electric motor when the drive device drives the electric motor to repeatedly rotate in the forward and reverse directions. The second rotational motion described above is a unidirectional rotational motion. The regenerative power generated by the motor as it repeatedly rotates in forward and reverse directions is supplied to the capacitor. Electric actuator.

2. The drive device supplies the surplus power from the regenerated power to the power supply. The electric actuator according to claim 1.

3. The drive unit supplies surplus power to the power source in proportion to the power consumed during acceleration of the electric motor and the regenerated power. The electric actuator according to claim 1.

4. The drive unit supplies power from the power source to the motor via the capacitor, and when the motor rotates in forward and reverse directions, it outputs to the power source any surplus power from the regenerated power recovered from the motor that was not consumed during acceleration. The electric actuator according to claim 1.

5. The drive unit includes a power regeneration converter connected to a power source and supplying power to the capacitor, and an inverter that converts the DC power output by the capacitor into AC power and supplies it to the motor. The power regeneration converter outputs to the power supply any surplus power from the regenerative power recovered from the electric motor that is not stored in the capacitor. The electric actuator according to claim 1.

6. The aforementioned power supply is composed of an AC power supply. The aforementioned power regeneration converter is composed of a bidirectional ADC converter. The electric actuator according to claim 5.

7. The power supply is composed of a DC power supply. The aforementioned power regeneration converter is composed of a bidirectional DC-DC converter. The electric actuator according to claim 5.

8. The drive device drives the electric motor so that it repeatedly rotates in forward and reverse directions at a required frequency of 3 Hz or higher. The electric actuator according to claim 1.

9. The motion transducer is A first motion converter that converts the aforementioned forward and reverse rotational motion into reciprocating linear motion, Includes a second motion converter that converts the aforementioned reciprocating linear motion into the aforementioned unidirectional rotational motion. The electric actuator according to claim 1.

10. The motion converter, A ball screw with a nut, A linear motion part fixed to the nut and moving linearly together with the nut, A rotating body that can rotate freely around its axis of rotation, A connecting rod rotatably connected to the eccentric portion of the rotating body with respect to the rotation axis and to the linear motion portion, including, The electric actuator according to claim 9.

11. The rotating body is a crankshaft, The connecting rod is rotatably connected to the crankpin of the crankshaft. The electric actuator according to claim 10.

12. The rotating body is a spindle, The connecting rod is rotatably connected to a projection formed at an eccentric position with respect to the rotation axis of the spindle. The electric actuator according to claim 10.

13. The system further includes a control device for controlling the aforementioned drive device, The control device controls the drive device to switch the rotation of the electric motor between forward and reverse rotation, avoiding the timing at which the linear motion unit reaches a dead point where no rotational force is generated in the rotating body by the movement of the linear motion unit. An electric actuator according to either claim 11 or claim 12.

14. The system further includes a control device for controlling the aforementioned drive device, The control device controls the drive device such that the torque of the electric motor is limited at least when the linear motion part reaches a dead point where no rotational force is generated in the rotating body by the movement of the linear motion part. An electric actuator according to either claim 11 or claim 12.

15. The motion converter, A first disc portion, which is rotatable around a first rotation axis and connected to the shaft of the electric motor, A second disc portion, which is rotatable around a second rotation axis, is connected to the output shaft of the motion transducer, The invention includes a connecting rod rotatably connected to a portion of the first disc portion that is eccentric with respect to the first axis of rotation and to a portion of the second disc portion that is eccentric with respect to the second axis of rotation. An electric actuator according to any one of claims 1 to 8.

16. An electric mobility device comprising an electric actuator according to any one of claims 1 to 15.

17. The aforementioned electric actuator and, 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, The wheel attached to the aforementioned drive shaft, The electric mobility device according to claim 16, having the following features.

18. The electric mobility device according to claim 16, which obtains a unidirectional propulsion force from a unidirectional rotational motion obtained by rotating the electric actuator in forward and reverse directions.

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