Controller and drive actuator

Abstract

To provide a technology capable of generating torque for acceleration or deceleration of a driven device in a transmission, apart from prime mover torque.SOLUTION: A control device 20 is used in a drive actuator 10 comprising: a prime mover 14; a continuously variable transmission 16 that changes the speed of rotation input from the prime mover 14 to an input shaft and outputs it from an output shaft to a driven device 12; and a speed change actuator 18 capable of changing a speed change ratio of the continuously variable transmission 16, and controls the prime mover 14 and the speed change actuator 18. When performing acceleration control to accelerate the driven device, the speed change ratio is increased to perform first torque generation control to generate a negative torque that decelerates the input shaft and a positive torque that accelerates the output shaft in the continuously variable transmission 16.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a control device used for a driving actuator.

Background Art

[0002] Patent Document 1 discloses a driving actuator including a prime mover and a transmission that changes the rotation input from the prime mover and outputs it to a driven device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It may be advantageous to use a driving actuator if torque for accelerating or decelerating a driven device can be generated in a transmission separately from prime mover torque generated by a prime mover.

[0005] Therefore, one object of the present disclosure is to provide a technique capable of generating torque for accelerating or decelerating a driven device in a transmission separately from prime mover torque.

Means for Solving the Problems

[0006] The control device of the present disclosure is used in a drive actuator including a prime mover, a continuously variable transmission that changes the rotation input from the prime mover to an input shaft and outputs it from an output shaft to a driven device, and a transmission actuator capable of changing the transmission ratio of the continuously variable transmission, and is a control device that controls the prime mover and the transmission actuator. When performing acceleration control to accelerate the driven device, first torque generation control is performed to generate a negative torque that decelerates the input shaft and a positive torque that accelerates the output shaft in the continuously variable transmission by increasing the transmission ratio.

[0007] Another control device of the present disclosure is used in a drive actuator including a prime mover, a continuously variable transmission that changes the rotation input from the prime mover to an input shaft and outputs it from an output shaft to a driven device, and a transmission actuator capable of changing the transmission ratio of the continuously variable transmission, and is a control device that controls the prime mover and the transmission actuator. When performing deceleration control to decelerate the driven device, second torque generation control is performed to generate a positive torque that accelerates the input shaft and a negative torque that decelerates the output shaft in the continuously variable transmission by decreasing the transmission ratio.

Advantages of the Invention

[0008] According to the present disclosure, torque for accelerating or decelerating the driven device can be generated in the transmission separately from the prime mover torque.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments for implementing the drive actuator of the present disclosure will be described. The same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted. In each drawing, for convenience of explanation, components are appropriately omitted, enlarged, or reduced. The drawings are to be viewed in accordance with the orientation of the reference numerals.

[0011] In this specification, the notations "first" and "second" are used only as formal descriptions for distinguishing a plurality of elements, and have no other substantial meaning. For example, these notations do not limit the order of each element to which they are attached. Also, the "second" element may exist without the "first" element existing.

[0012] Refer to FIG. 1. The drive actuator 10 is used to drive the driven device 12. The driven device 12 is, for example, a ball screw device used in a conveying device, a positioning device, or the like. The driven device 12 includes a rotation drive unit 12a that is rotationally driven by the drive actuator 10. The rotation drive unit 12a is, for example, a screw shaft used in a ball screw device. Specific examples of the driven device 12 are not particularly limited, and may be a part of industrial machines (machine tools, construction machines, etc.), robots (industrial robots, service robots, etc.), transportation equipment (conveyors, vehicles, etc.), or the like.

[0013] The drive actuator 10 includes a prime mover 14, a continuously variable transmission 16 that changes the rotation input from the prime mover 14 to the input shaft and outputs it to the driven device 12 from the output shaft, a transmission actuator 18 capable of changing the transmission ratio of the continuously variable transmission 16, and a control device 20 that controls the prime mover 14 and the transmission actuator 18. In addition, the drive actuator 10 includes a first rotation detector 22 that detects the rotation of the input shaft of the continuously variable transmission 16, and a second rotation detector 24 that detects the rotation of the output shaft of the continuously variable transmission 16. The first rotation detector 22 may detect the rotation of the prime mover 14 instead of the input shaft of the continuously variable transmission 16. The second rotation detector 24 may detect the rotation of the driven device 12 instead of the output shaft of the continuously variable transmission 16. The rotation detectors 22 and 24 are constituted by an encoder, a torque sensor, or the like. The rotation detectors 22 and 24 output the detection results regarding their detection targets to the control device 20.

[0014] The prime mover 14 can rotate a prime mover shaft (not shown) by the torque generated inside itself (hereinafter referred to as prime mover torque), and then output the rotation from the prime mover shaft to the continuously variable transmission 16. The prime mover 14 of the present embodiment is a motor (electric motor) that rotates the prime mover shaft using electrical energy. The motor can rotate the prime mover shaft by the prime mover torque generated by the cooperation of the stator and the rotor. The specific example of the prime mover 14 is not particularly limited, and for example, an engine that rotates the prime mover shaft using thermal energy may also be used.

[0015] The transmission actuator 18 can change the transmission ratio of the continuously variable transmission 16 by inputting power to the continuously variable transmission 16. The transmission actuator 18 of the present embodiment is a linear actuator, and inputs power along the axial direction of the continuously variable transmission 16 to the continuously variable transmission 16. The specific type of the transmission actuator 18 is not particularly limited as long as it can change the transmission ratio of the continuously variable transmission 16, and a rotary actuator or the like may also be used.

[0016] The control device 20 is composed of a combination of hardware elements and software elements, or only hardware elements. As the hardware elements, for example, a processor, a ROM (Read Only Memory), and a RAM (Random Access Memory) are used. As the software elements, for example, programs such as an operating system and an application are used. The part used for controlling the prime mover 14 and the part used for controlling the shift actuator 18 may be realized by a common hardware element or software element, or may be realized by separate hardware elements or software elements.

[0017] The control device 20 can change the prime mover torque by controlling the prime mover 14. The control device 20 can change the gear ratio of the continuously variable transmission 16 by controlling the shift actuator 18.

[0018] The control device 20 controls the prime mover 14 and the shift actuator 18 using the electric power supplied from the external main power supply 26 or the auxiliary power supply 28. When the control device 20 detects that there is no abnormality (such as a power failure, etc.) in the main power supply 26 by an abnormality detection device (not shown), it controls the prime mover 14 and the shift actuator 18 using the electric power supplied from the main power supply 26. When the control device 20 detects an abnormality in the main power supply 26 by the abnormality detection device, it controls the prime mover 14 and the shift actuator 18 using the electric power supplied from the auxiliary power supply 28. In the present embodiment, the acceleration control and the deceleration control described below may be performed using the electric power supplied from the main power supply 26.

[0019] Refer to FIG. 2. The continuously variable transmission 16 includes an input shaft 40 to which rotation is input from the prime mover 14, a transmission mechanism 42 that transmits the rotation input to the input shaft 40 after changing the speed to the output shaft 44, an output shaft 44 that outputs the rotation transmitted from the transmission mechanism 42 to the driven device, and a gear ratio changing mechanism 46 that changes the gear ratio of the transmission mechanism 42. The transmission mechanism 42 includes a plurality of friction transmission elements 48 (described later) that transmit rotation by friction. Rotation is transmitted from the input shaft 40 to the output shaft 44 via the plurality of friction transmission elements 48.

[0020] The continuously variable transmission 16 can continuously change the transmission ratio using a transmission ratio changing mechanism 46 by means of a transmission actuator 18. Here, the transmission ratio means the ratio of the output rotational speed to the ideal input rotational speed that can be achieved when there is no slippage between a plurality of friction transmission elements 48. When the ideal input rotational speed and output rotational speed that can achieve this transmission ratio are respectively referred to as the ideal input rotational speed and ideal output rotational speed, the transmission ratio is represented by the ideal output rotational speed / ideal input rotational speed. Here, the input rotational speed is the rotational speed of the input shaft 40, and the output rotational speed means the rotational speed of the output shaft 44.

[0021] The continuously variable transmission 16 of this embodiment is an infinitely variable transmission (IVT), and is configured such that the variable range of the transmission ratio includes zero (= 1 / ∞). Here, an example of such a continuously variable transmission 16 will be described, but its specific example is not particularly limited. For example, the continuously variable transmission 16 may be a toroidal continuously variable transmission or the like. Also, the continuously variable transmission 16 may not include zero in its variable range. In this case, the continuously variable transmission may be, for example, a belt-type continuously variable transmission, a chain-type continuously variable transmission, or the like.

[0022] The input shaft 40 includes an input member 40a to which rotation is input from the prime mover 14, a shaft 40b connected to the input member 40a, and a sleeve 40c fixed to the shaft 40b. The specific structure of the input shaft 40 is not particularly limited as long as it can transmit rotation from the prime mover 14 to the transmission mechanism 42. Here, the input shaft 40 shows an example constituted by a plurality of members, but it may be constituted by a single member, and the number of its members is not particularly limited either.

[0023] The plurality of friction transmission elements 48 constituting the speed change mechanism 42 include an input raceway ring 50 provided so as to be integrally rotatable with the input shaft 40, a first support raceway ring 52 rotatably supported by the input shaft 40, a second support raceway ring 56 provided so as to be axially movable within the casing 54 of the continuously variable transmission 16, an output raceway ring 58 provided so as to be integrally rotatable with the output shaft 44, and a plurality of planetary rolling elements 60 that roll on the respective raceway rings 50, 52, 56, 58. The plurality of planetary rolling elements 60 are pressed against the output raceway ring 58 by a pressing force applied from the second support raceway ring 56 by a pressing force applying mechanism (not shown).

[0024] When the input raceway ring 50 rotates, the planetary rolling element 60 revolves around the rotation axis L40 (revolution axis) of the input shaft 40 while rotating around its own rotation axis L60. When the planetary rolling element 60 revolves, the output raceway ring 58 rotates around the rotation axis L40 following it. At this time, ideally, the output raceway ring 58 rotates at an output rotation speed obtained by multiplying the input rotation speed of the input raceway ring 50 by the speed ratio. This speed ratio is determined according to the inclination angle of the rotation axis L60 with respect to the rotation axis L40 and is changed by the speed ratio changing mechanism 46.

[0025] The output shaft 44 includes an output raceway ring 58 and an output member 44a that is integrally rotationally connected to the output raceway ring 58 and outputs rotation to the driven device 12. The specific structure of the output shaft 44 is not particularly limited as long as rotation can be transmitted from the speed change mechanism 42 to the driven device 12. Here, the output shaft 44 shows an example of being constituted by a plurality of members, but it may be constituted by a single member, and the number of its members is not particularly limited either.

[0026] The speed ratio change mechanism 46 of this embodiment can change the speed ratio by changing the position of the input orbital gear 50. The speed ratio change mechanism 46 includes a shaft 46a that can move axially by the power output from the shift actuator 18, and a ring member 46b that can move axially integrally with the shaft 40b. The ring member 46b rotatably supports the input shaft 40 via a bearing 46c and can move axially integrally with the input shaft 40 by a retaining ring or the like. The specific example of the speed ratio change mechanism 46 is not particularly limited, and various similar mechanisms adopted in the continuously variable transmission 16 may be adopted.

[0027] When an axial driving force is input from the shift actuator 18 to the shaft 46a, the input shaft 40 (including the input orbital gear 50 and the first support orbital gear 52) moves axially integrally with the ring member 46b. When the input orbital gear 50 and the first support orbital gear 52 move axially with respect to the second support orbital gear 56 and the output orbital gear 58, the inclination angle of the rotation axis L60 of the rotation axis L40 of the planetary rolling element 60 is changed, and the speed ratio is changed according to the inclination angle. This speed ratio becomes zero (= 1 / ∞) when the rotation axis L60 of the rotation axis L40 is parallel, and continuously increases as the inclination angle of the rotation axis L60 of the rotation axis L40 increases. That is, the speed ratio can be changed steplessly (continuously), and is configured to include zero in its variable range.

[0028] Next, when explaining the control content by the control device 20, the underlying concept will be explained. The driven device 12, the rotation, moment of inertia, angular acceleration, angular velocity, acceleration torque, and deceleration torque of the prime mover 14 described below refer to those related to the entire rotating object in the object of reference. For example, when referring to the acceleration torque of the prime mover 14, it refers to the acceleration torque of the entire object (such as the prime mover shaft) rotating in the prime mover 14. Also, when referring to the moment of inertia of the driven device 12, it refers to the moment of inertia of the entire object (such as the rotary drive unit 12a) rotating in the driven device 12. Also, the acceleration torque and deceleration torque here refer to the torque required to accelerate or decelerate the object being referred to.

[0029] At a certain moment during the acceleration of the driven device 12, the output torque T is output from the output shaft 44 of the drive actuator 10 to the driven device 12. A The following equation (1) holds. Here, J L is the moment of inertia of the driven device 12 (kg·m 2 ), W L is the angular acceleration of the driven device 12 (rad / s 2 ), and T L is the load torque of the driven device 12 (N·m). T A = J L × W L + T L ···(1)

[0030] When the prime mover 14 generates the prime mover torque T M the following equation (2) holds. Here, J M is the moment of inertia of the prime mover 14 (kg·m 2 ), W M is the angular acceleration of the prime mover 14 (rad / s 2 ), and Z is the transmission ratio (-) of the continuously variable transmission 16. In this specification, since the moment of inertia of the continuously variable transmission 16 is sufficiently small, this influence is omitted. Also, the influence of viscosity, rigidity, and power loss in each part of the drive actuator 10 is omitted. T M = J M × W M + Z × T A ···(2)

[0031] Equation (3) can be derived from equations (1) and (2). T M = J M × W M + Z × [J L × W L + T L ···(3)

[0032] As can be understood from this equation (3), the prime mover torque T M of the prime mover 14 is usually the acceleration torque of the prime mover 14 (J M × W M ), the acceleration torque of the driven device 12 (Z × JL ×W L ) The load torque of the driven device 12 (Z×T L ) can be represented by the sum of

[0033] Based on the above, the control content by the control device 20 will be described. First, the outline of the acceleration control for accelerating the driven device 12 will be described. Here, the case of accelerating the driven device 12 in a stopped state where rotation has stopped will be described as an example. This acceleration control is performed in the order of the initial control → the first torque generation control described below.

[0034] Refer to Fig. 3(A). Fig. 3(A) schematically shows only the input shaft 40, the transmission mechanism 42, and the output shaft 44 of the continuously variable transmission 16. The same applies to Fig. 3(B), Fig. 4(A), and Fig. 4(B) hereinafter.

[0035] First, by controlling the shift actuator 18, an initial control is performed to accelerate the prime mover 14 by generating a prime mover torque by controlling the prime mover 14 in a state where the speed ratio Z of the continuously variable transmission 16 is substantially zero. In the initial control, the prime mover 14 is accelerated so that the angular velocity of the prime mover 14 becomes a sufficiently high angular velocity. At this time, the input shaft 40 of the continuously variable transmission 16 is similarly accelerated. Since the prime mover torque is generated while maintaining the speed ratio Z substantially zero, the driven device 12 and the output shaft 44 of the continuously variable transmission 16 are maintained in a stopped state. At this time, the prime mover torque T M Since the speed ratio Z is zero, it can be expressed by the following formula (4) using formula (3). T M =J M ×W M ···(4)

[0036] Refer to FIG. 3(B). Next, under the condition that the prime mover 14 is rotating at a sufficiently high angular velocity, first torque generation control is performed to continuously increase the transmission ratio substantially from zero by controlling the transmission actuator 18. When performing this first torque generation control, there are two cases: one is when the prime mover torque of the prime mover 14 is set to zero (control example 1), and the other is when the prime mover 14 generates prime mover torque (control example 2). First, control example 1 will be described. Hereinafter, the rotation direction D40 of the input shaft 40 is referred to as the forward rotation direction, and the rotation direction opposite thereto is referred to as the reverse rotation direction.

[0037] (Control example 1) The actual output rotation speed of the output shaft 44 with respect to the actual input rotation speed of the input shaft 40 is referred to as the actual rotation speed ratio (= actual output rotation speed / actual input rotation speed). In this first torque generation control, the transmission ratio is increased so that the transmission ratio (= ideal output rotation speed / ideal input rotation speed) becomes larger than the actual rotation speed ratio at the start of the first torque generation control. When starting the first torque generation control, since the prime mover 14 is rotated with the output shaft 44 of the continuously variable transmission 16 stopped by initial control, the actual rotation speed ratio also becomes zero. Therefore, by starting the first torque generation control, the transmission ratio is always larger than the actual rotation speed ratio.

[0038] When the transmission ratio (= ideal output rotation speed / ideal input rotation speed) is larger than this actual rotation speed ratio (= actual output rotation speed / actual input rotation speed), slippage occurs between the respective friction transmission elements 48 of the continuously variable transmission 16. When the transmission ratio is larger than the actual rotation speed ratio, in the friction transmission element (input track ring 50 in the embodiment) provided so as to be rotatable integrally with the input shaft 40, slippage S1 in the forward rotation direction occurs with respect to the friction transmission element (planetary rolling element 60 in the embodiment) adjacent to the output side. Also, in the friction transmission element (output track ring 58 in the embodiment) provided so as to be rotatable integrally with the output shaft 44, slippage S2 in the reverse rotation direction occurs with respect to the friction transmission element (planetary rolling element 60 in the embodiment) adjacent to the input side. At the same time, reaction torques are generated on the input shaft 40 and the output shaft 44 in directions that resist the slippage as reaction forces to the slippage. At this time, a negative torque F1 in the direction opposite to the slippage S1 (reverse rotation direction) is generated as a reaction torque on the input shaft 40, and a positive torque F2 in the direction opposite to the slippage S2 (forward rotation direction) is generated as a reaction torque on the output shaft 44.

[0039] Thus, in the first torque generation control, by increasing the gear ratio while the prime mover 14 is rotating, due to the slip in the continuously variable transmission 16, the opposing negative torque F1 and positive torque F2 can be generated within the continuously variable transmission 16. In other words, in the first torque generation control, the gear ratio is increased so as to generate a negative torque F1 that decelerates the input shaft 40 and a positive torque F2 that accelerates the output shaft 44 within the continuously variable transmission. To achieve this, it is a prerequisite to increase the gear ratio until it becomes larger than the actual rotation speed ratio at the time when the first torque generation control is started.

[0040] The negative torque F1 of the input shaft 40 can decelerate the prime mover 14, and the positive torque F2 of the output shaft 44 can accelerate the driven device 12. As a result, the actual input rotation speed of the input shaft 40 decreases and the actual output rotation speed of the output shaft 44 increases, so the above-mentioned actual rotation speed ratio (= actual output rotation speed / actual input rotation speed) gradually increases. After stopping the increase in the gear ratio, when this actual rotation speed ratio has increased until it becomes the gear ratio, the load torque T of the driven device 12 L and the negative torque F1 and positive torque F2 that are in balance with it occur within the continuously variable transmission 16. After this, due to the influence of the load torque T of the driven device 12 caused by friction or the like, the driven device 12, the prime mover 14, and the continuously variable transmission 16 (including the input shaft 40 and the output shaft 44) decelerate while maintaining the actual rotation speed ratio at the gear ratio. The above operations can be regarded as using the kinetic energy stored in the prime mover 14 to generate the output torque (positive torque F2) of the drive actuator 10, thereby converting the kinetic energy of the prime mover 14 into the kinetic energy of the driven device 12. L When the negative torque F1 and positive torque F2 are generated within the continuously variable transmission 16, the output torque T of the drive actuator 10 at a certain moment

[0041] can be expressed by the following equation (5) from the above-mentioned equation (2). In this example (control example 1), since the prime mover torque T A becomes zero, T in equation (2) M is zero, soM The term becomes zero. T A = -(1 / Z)J M ×W M ···(5)

[0042] The first term on the right side of Equation (5) represents the positive torque F2 caused by slippage. Since the prime mover 14 decelerates, W M < 0, and the first term is positive. From Equation (5), T A > 0, and it can be understood that the output torque T A can accelerate the driven device 12.

[0043] (Control Example 2) Next, Control Example 2 will be described. In Control Example 2, under the state where the prime mover torque is generated by the prime mover 14 by controlling the prime mover 14, the first torque generation control for increasing the transmission ratio is performed by controlling the transmission actuator 18, so that a negative torque F1 on the input shaft 40 and a positive torque F2 on the output shaft 44 are generated in the continuously variable transmission 16. At this time, the prime mover 14 generates a prime mover torque in the positive rotation direction D40. At this time, the output torque T of the drive actuator 10 A can be expressed by the following Equation (6) from the aforementioned Equation (2). T A = T M / Z-(1 / Z)J M ×W M ···(6)

[0044] As can be understood from the comparison with Equation (5), the output torque T A is the sum of the first term obtained by dividing the prime mover torque T M (positive) of the prime mover 14 by the transmission ratio Z(positive) with respect to the second term on the right side indicating the positive torque F2 caused by slippage. Also, similar to Equation (5), since the prime mover 14 decelerates due to the negative torque F1, W M < 0, and the second term is positive. Therefore, compared with the case of Control Example 1 where the prime mover torque is set to zero, the output torque T A can be increased.

[0045] The following equations (7) and (8) can be derived from equation (5) of Control Example 1 and equation (6) of Control Example 2. -(1 / Z)J M ×W M =J L W L + T L ··· (7) T M / Z-(1 / Z)J M ×W M =J L W L + T L ··· (8)

[0046] If the load torque T L is the same in equations (7) and (8), the angular acceleration torque W L of the driven device 12 is greater in Control Example 2 of equation (8) than in Control Example 1 of equation (7). This means that Control Example 2 can accelerate the driven device 12 faster than Control Example 1.

[0047] Next, the specific operation of the acceleration control performed by the control device 20 will be described. Here, the operation in the case of performing acceleration control to accelerate the driven device 12 in a stopped state will be described. This acceleration control is performed in the order of initial control → first torque generation control as described above.

[0048] The control device 20 performs acceleration control when a predetermined acceleration condition is satisfied. The acceleration condition is, for example, receiving an acceleration command from an external controller to accelerate the driven device 12. The acceleration control for accelerating the stopped driven device 12 is performed when the second rotation detector 24 detects the stop of the rotation of the rotation driving unit 12a of the driven device 12 or the output shaft 44 of the continuously variable transmission 16 when the acceleration condition is satisfied.

[0049] The control device 20 performs initial control to accelerate the prime mover 14 by generating prime mover torque through the control of the prime mover 14 in a state where the transmission ratio Z of the continuously variable transmission 16 is made substantially zero by the control of the shift actuator 18. Here, "substantially zero" includes not only mathematically exact zero, 1 / ∞, but also values close to zero that are very small compared to the transmission ratios used in general power transmission applications. This "substantially zero" includes, for example, values with a transmission ratio of 1 / 1000 or less.

[0050] In the initial control, the prime mover 14 is accelerated so that the angular velocity of the prime mover 14 becomes a sufficiently high angular velocity. To achieve this, the prime mover 14 may be accelerated until the angular velocity of the input shaft 40 of the prime mover 14 or the continuously variable transmission 16 detected by the first rotation detector 22 reaches the target angular velocity set in the control device 20. This target angular velocity is set to a sufficiently high angular velocity that can be achieved by the prime mover 14.

[0051] Next, under the condition that the prime mover 14 is rotating at a sufficiently high angular velocity (the state where the angular velocity of the prime mover 14 has reached the target angular velocity), first torque generation control is performed to continuously increase the transmission ratio from substantially zero by the control of the shift actuator 18. To achieve this, the transmission ratio may be increased until the transmission ratio of the continuously variable transmission 16 exceeds the target lower limit transmission ratio set in the control device 20. At this time, the upper limit value of the transmission ratio is not particularly limited, but is, for example, 1 / 15. In this case, in the first torque generation control, when the transmission ratio of the continuously variable transmission 16 exceeds the target lower limit transmission ratio, the increase in the transmission ratio is stopped.

[0052] The target angular velocity of the prime mover 14 in the initial control and the target gear ratio of the continuously variable transmission 16 in the first torque generation control may be set according to the target angular velocity to be achieved by the driven device 12 set in the control device 20. Specifically, the angular velocity of the driven device 12 accelerated using the positive torque F2 caused by the slip generated by the first torque generation control has a correlation between the target angular velocity of the prime mover 14 in the initial control and the target gear ratio of the continuously variable transmission 16. The higher the target angular velocity of the prime mover 14 in this initial control, the higher the angular velocity of the driven device 12 after acceleration, and the higher the target gear ratio, the higher the angular velocity of the driven device 12 after acceleration. Therefore, relationship information such as relational expressions and tables indicating these correlations may be stored in the storage unit in advance, and based on the relationship information and the target angular velocity of the driven device 12, the target angular velocity of the prime mover 14 and the target gear ratio of the continuously variable transmission 16 that can achieve the target angular velocity may be set.

[0053] After increasing the gear ratio by the first torque generation control and then stopping the increase, when the actual rotation speed ratio increases until it becomes the gear ratio, as described above, the load torque T of the driven device 12 L and the negative torque F1 and positive torque F2 that balance it are generated in the continuously variable transmission 16. When the actual rotation speed ratio has increased until it matches the gear ratio in this way, if the driven device 12 has not reached the target angular velocity, the prime mover torque for accelerating the driven device 12 may be generated until the driven device 12 reaches the target angular velocity. In this case, it is necessary to determine whether the actual rotation speed ratio has matched the gear ratio. In making this determination, for example, it may be based on the detection results of the input rotation speed of the input shaft 40 detected by the first rotation detector 22 and the output rotation speed of the output shaft 44 detected by the second rotation detector 24. In this case, the actual rotation speed ratio may be obtained from the detected value of the input rotation speed and the detected value of the output rotation speed, and when the actual rotation speed ratio substantially matches the gear ratio, it may be determined that the actual rotation speed ratio has matched the gear ratio.

[0054] In addition, when starting the driven device 12 in a stopped state, the target angular velocity of the prime mover 14 in the initial control and the target gear ratio of the continuously variable transmission 16 in the first torque generation control may be set so that the positive torque F2 required for the start can be generated by the first torque generation control. In this case, when accelerating the driven device 12 after starting it, the torques F1 and F2 caused by slippage may be utilized, or only the prime mover torque may be utilized without using the torques F1 and F2 caused by slippage.

[0055] In the first torque generation control, when generating the torques F1 and F2 caused by slippage in the continuously variable transmission 16, it is not necessary to generate the prime mover torque for accelerating the driven device 12 as in the above control example 1, or the prime mover torque may be generated as in the above control example 2.

[0056] The effects of the above acceleration control will be described.

[0057] When performing acceleration control, the control device 20 can perform the first torque generation control that generates the negative torque F1 for decelerating the input shaft 40 and the positive torque F2 for accelerating the output shaft 44 in the continuously variable transmission 16 by increasing the gear ratio. As a result, separately from the prime mover torque, the positive torque F2 for accelerating the driven device 12 can be generated in the continuously variable transmission 16.

[0058] FIG. 4 is a diagram showing the difference in the torques generated in the conventional example and control examples 1 and 2. In the conventional example, the total of the acceleration torque of the prime mover 14, the acceleration torque of the driven device 12, and the load torque is covered by the prime mover torque.

[0059] Control Example 1 covers the total of the acceleration torque and the load torque of the driven device 12 with the positive torque F2 resulting from the slip generated by the first torque generation control. In Control Example 1, when the positive torque F2 is being generated, the acceleration torque of the prime mover 14 becomes zero. Also, when accelerating the prime mover 14 by the initial control, the prime mover torque to be covered by the prime mover 14 is only the acceleration torque of the prime mover 14. That is, when accelerating the driven device 12 using only the positive torque F2 generated within the continuously variable transmission 16 as in Control Example 1, it becomes unnecessary to cover the total of the acceleration torque of the prime mover 14, the acceleration torque of the driven device 12, and the load torque with only the prime mover torque. Therefore, the load on the prime mover 14 can be reduced when accelerating the driven device 12, which is advantageous for miniaturizing the prime mover 14.

[0060] Control Example 2 is such that, in covering the total of the acceleration torque and the load torque of the driven device 12, in addition to the positive torque F2 resulting from the slip generated by the first torque generation control, the prime mover torque is added. This is advantageous in increasing the output torque of the drive actuator 10 for accelerating the driven device 12 without increasing the size of the prime mover 14. Also, by increasing the output torque in this way, the acceleration torque of the driven device 12 can be increased, and the acceleration time until the driven device 12 reaches the target angular velocity can be shortened.

[0061] Further, the control device 20 performs the first torque generation control after performing the initial control of accelerating the prime mover 14 with the transmission ratio of the continuously variable transmission 16 substantially set to zero. Thus, the prime mover 14 can be accelerated under the condition that the load torque and the acceleration torque of the driven device 12 do not occur due to the initial control, and the kinetic energy of the prime mover 14 can be effectively increased. The kinetic energy of the prime mover 14 increased in this way can be converted into the kinetic energy of the driven device 12 by the first torque generation control, and the driven device 12 can be effectively accelerated.

[0062] Further, when starting the driven device 12 in a stopped state, it is necessary to output an output torque from the drive actuator 10 that overcomes the static frictional force acting on the driven device. The output torque required to start this driven device is greater than the output torque required during the operation of the driven device 12. If the output torque required for this start is covered only by the prime mover torque, the prime mover torque required for the prime mover 14 increases, leading to an increase in the size of the prime mover 14. According to the present embodiment, by performing the first torque generation control after the initial control, the positive torque F2 generated in the continuously variable transmission 16 starts the driven device 12 in a stopped state. Therefore, since the output torque required to start the driven device 12 can be covered using other than the prime mover torque, the prime mover torque required for the prime mover 14 can be reduced, which is advantageous for reducing the size of the prime mover 14.

[0063] Next, an outline of the deceleration control for decelerating the driven device 12 will be described.

[0064] Referring to FIG. 5(A). In the deceleration control, second torque generation control for continuously decreasing the gear ratio is performed while the driven device 12 and the prime mover 14 are rotating. The second torque generation control will be performed while the input shaft 40 and the output shaft 44 of the continuously variable transmission 16 are rotating. In this second torque generation control, the gear ratio is decreased so as to be smaller than the actual rotation speed ratio when the second torque generation control is started.

[0065] Referring to FIG. 5(B). When the gear ratio is smaller than the actual rotation speed ratio, in the friction transmission element (input race ring 50 in the embodiment) provided to be integrally rotatable with the input shaft 40, a slip S3 in the reverse rotation direction occurs with respect to the friction transmission element (planetary rolling element 60 in the embodiment) adjacent to the output side. Also, in the friction transmission element (output race ring 58 in the embodiment) provided to be integrally rotatable with the output shaft 44, a slip S4 in the forward rotation direction occurs with respect to the friction transmission element 48 (planetary rolling element 60 in the embodiment) adjacent to the input side. At the same time, a positive torque F3 in the direction opposite to the slip S3 (forward rotation direction) is generated as a reaction torque on the input shaft 40, and a negative torque F4 in the direction opposite to the slip S4 (reverse rotation direction) is generated as a reaction torque on the output shaft 44.

[0066] Thus, in the second torque generation control, by reducing the gear ratio while the driven device 12 is rotating, due to slippage in the continuously variable transmission 16, the opposing positive torque F3 and negative torque F4 can be generated within the continuously variable transmission 16. In other words, in the second torque generation control, the gear ratio is reduced so as to generate a positive torque F3 that accelerates the input shaft 40 and a negative torque F4 that decelerates the output shaft 44 within the continuously variable transmission 16. To achieve this, it is a prerequisite to reduce the gear ratio until it becomes smaller than the actual rotation speed ratio at the time when the second torque generation control is started.

[0067] The positive torque F3 of the input shaft 40 can accelerate the prime mover 14, and the negative torque F4 of the output shaft 44 can decelerate the driven device 12. As a result, the actual input rotation speed of the input shaft 40 increases and the actual output rotation speed of the output shaft 44 decreases, so the aforementioned actual rotation speed ratio (= actual output rotation speed / actual input rotation speed) gradually decreases. After stopping the reduction of the gear ratio, when this actual rotation speed ratio has decreased until it becomes equal to the gear ratio, the positive torque F3 and negative torque F4 caused by slippage within the continuously variable transmission 16 no longer occur within the continuously variable transmission 16. The above operation can be regarded as using the kinetic energy stored in the driven device 12 to generate a reverse driving torque (positive torque F3) of the prime mover 14, thereby converting the kinetic energy of the driven device 12 into the kinetic energy of the prime mover 14.

[0068] Next, the specific operation of the deceleration control performed by the control device 20 will be described. The control device 20 performs deceleration control when a predetermined deceleration condition is satisfied. The deceleration condition is, for example, receiving a deceleration command for decelerating the driven device 12 from an external controller.

[0069] When performing deceleration control, the control device performs second torque generation control to continuously decrease the gear ratio by controlling the transmission actuator 18 when the driven device 12 is in a rotating state. To achieve this, the gear ratio may be decreased until the gear ratio of the continuously variable transmission 16 falls below the target upper limit gear ratio. At this time, the lower limit value of the gear ratio becomes zero. In this case, in the second torque generation control, when the gear ratio of the continuously variable transmission 16 falls below the target upper limit gear ratio, the decrease in the gear ratio is stopped.

[0070] When the gear ratio of the continuously variable transmission 16 becomes a very small value, when the slippage between the friction transmission elements 48 in the continuously variable transmission 16 begins to disappear, the rotation of the driven device 12 is locked. The lock here means a state where the driven device 12 does not move at all or hardly moves when the user tries to rotate the driven device 12. The gear ratio range in which the rotation of the driven device 12 is locked in this way is called the lock gear ratio range. This lock gear ratio range is, for example, from zero (= 1 / ∞) to about 1 / several hundreds.

[0071] In the second torque generation control, the gear ratio may be decreased until this lock gear ratio range is reached. Thereby, the driven device 12 can be stopped without generating the prime mover torque for decelerating the driven device 12.

[0072] Also, in the second torque generation control, if the speed ratio is decreased up to the lock speed ratio range, a large impact load may be generated in the continuously variable transmission 16 due to the sudden stop of the rotation of the driven device 12. Therefore, in the second torque generation control, the decrease in the speed ratio may be stopped before reaching the lock speed ratio range. Thereby, the generation of an impact load due to the sudden stop of the rotation of the driven device 12 can be avoided. At this time, in performing the deceleration control, after stopping the decrease in the speed ratio before reaching the lock speed ratio range, it is preferable to generate a prime mover torque for decelerating the driven device 12 by the prime mover 14. This prime mover torque may be generated until the rotation of the driven device 12 stops. Thereby, while decelerating the driven device 12 by the second torque generation control and avoiding a sudden stop of the driven device 12, the driven device 12 can be slowly stopped using the prime mover torque of the prime mover 14 as well.

[0073] In the second torque generation control, when generating the torques F3 and F4 caused by slippage in the continuously variable transmission 16 by decreasing the speed ratio, it is not necessary to generate a prime mover torque for decelerating the driven device 12 as in the above-described control example 1. In addition to this, as in control example 2, the prime mover torque may be generated.

[0074] The effects of the above deceleration control will be described.

[0075] When performing deceleration control, the control device 20 can perform second torque generation control that generates a positive torque F3 for accelerating the input shaft 40 and a negative torque F4 for decelerating the output shaft 44 in the continuously variable transmission 16 by decreasing the speed ratio. Thereby, separately from the prime mover torque, a negative torque F4 for decelerating the driven device 12 can be generated in the continuously variable transmission 16.

[0076] When decelerating the driven device 12, it is usually necessary to generate the deceleration torque of the prime mover 14 and the deceleration torque of the driven device 12. When decelerating the driven device 12 using only the negative torque F4 generated in the continuously variable transmission 16 as in this embodiment, it is not necessary to cover the sum of the deceleration torque of the prime mover 14 and the deceleration torque of the driven device 12 only with the prime mover torque. As a result, the load on the prime mover can be reduced when decelerating the driven device, which is advantageous for miniaturizing the prime mover.

[0077] Also, when generating the prime mover torque in addition to the negative torque F4 generated in the continuously variable transmission 16 in order to decelerate the driven device 12, it is advantageous for increasing the output torque of the drive actuator 10 for decelerating the driven device 12 without increasing the size of the prime mover 14.

[0078] Next, other control contents by the control device 20 will be described. The first torque generation control used for the above acceleration control and the second torque generation control used for the deceleration control may be combined. For example, by the second torque generation control used for the deceleration control, the prime mover 14 rotates at high speed due to the positive torque F3 generated in the continuously variable transmission 16. When the prime mover 14 is in a rotating state due to the second torque generation control for the prime mover 14 or the like, when performing the acceleration control by the control device 20, the first torque generation control may be performed while the rotation of the prime mover 14 by that control continues. It can also be said that the first torque generation control may be performed before the rotation of the prime mover 14 by the same control stops.

[0079] As a result, the driven device 12 can be accelerated by using the kinetic energy stored in the prime mover 14 by the previous control (here, the second torque generation control) for the prime mover 14 or the like. Compared with the case where the kinetic energy used for accelerating the driven device 12 is regenerated by the prime mover torque after the previous control for the prime mover 14 or the like, the energy consumption by the prime mover 14 is reduced, and the energy saving performance of the drive actuator 10 can be improved. In particular, when the second torque generation control is performed before the start of the acceleration control, the prime mover 14 is more likely to rotate at a high speed, and accordingly, a large amount of kinetic energy is more likely to be stored in the prime mover 14, and the driven device 12 can be effectively accelerated by the first torque generation control.

[0080] From the viewpoint of improving the energy saving performance of the drive actuator 10 in this way, when the prime mover 14 is rotated by the control of the control device 20 for at least one of the prime mover 14 and the transmission actuator 18 performed before the start of the acceleration control, the first torque generation control may be performed while the rotation of the prime mover 14 by the control continues. Here, as such "control of the control device 20 performed before the start of the acceleration control", the second torque generation control is exemplified, but the specific example of this control is not limited to this. For example, an isometric control for maintaining the driven device 12 in an isometric state by the control device 20 may be used. Further, when this control is the second torque generation control, when the prime mover torque for decelerating the driven device 12 is not generated as described above, only the control for reducing the transmission ratio for the transmission actuator 18 is performed. On the other hand, when the prime mover torque for decelerating the driven device 12 is generated as described above, the control for both the transmission actuator 18 and the prime mover 14 is performed.

[0081] Also, at this time, in order to maintain the rotational state of the prime mover 14 during the waiting period from the completion of the control of the control device 20 for the prime mover 14 etc. before the start of the acceleration control until the start of the first torque generation control, the prime mover 14 may be controlled so as not to apply a torque for braking the prime mover 14. Even if the drive actuator 10 is provided with a braking device for braking the prime mover 14, during the waiting period, the braking device may be controlled so as not to apply a braking torque by the braking device.

[0082] Next, a modified example of the drive actuator 10 will be described. Refer to FIG. 6. The prime mover 14 includes, in addition to the prime mover shaft 14a, a prime mover housing 14b from which the prime mover shaft 14a protrudes.

[0083] The drive actuator 10 of the present embodiment includes a flywheel 70 attached to the prime mover shaft 14a. The flywheel 70 is used to increase the moment of inertia of the entire rotating system by rotating together with the prime mover shaft 14a of the prime mover 14. The attachment position of the flywheel 70 to the prime mover shaft 14a is not particularly limited. Here, an example is shown in which the flywheel 70 is attached to the anti-load side portion of the prime mover shaft 14a protruding from the prime mover housing 14b to the anti-load side (opposite side to the continuously variable transmission 16). Instead of this, as shown by the two-dot chain line, it may be attached to the load side portion of the prime mover shaft protruding from the prime mover housing 14b to the load side (side of the continuously variable transmission 16).

[0084] Thereby, when performing the above-described acceleration control, in addition to the kinetic energy of the prime mover 14, the kinetic energy of the flywheel 70 can be converted into the kinetic energy of the driven device 12, which is advantageous for the acceleration of the driven device 12. Also, when performing the above-described deceleration control, the kinetic energy of the driven device can be converted into the kinetic energy of the flywheel 70 in addition to the kinetic energy of the prime mover, which is advantageous for the deceleration of the driven device 12.

[0085] The above embodiments are illustrative. The technical ideas abstracted from these should not be construed as being limited to the content of the embodiments. Many design changes such as component changes, additions, deletions, etc. are possible for the content of the embodiments. In the foregoing embodiments, with respect to the content for which such design changes are possible, the notation "embodiment" is attached and emphasized. However, design changes are also permitted for content without such notation. The hatching attached to the cross-section of the drawing does not limit the material of the object to which the hatching is attached. Also, what is obtained by mutually substituting any of the components and expressions of the present disclosure among a method, an apparatus, a system, etc. is also valid as an aspect of the present disclosure.

Description of Reference Numerals

[0086] 10... drive actuator, 12... driven device, 14... prime mover, 14a... prime mover shaft, 16... continuously variable transmission, 18... shift actuator, 20... control device, 40... input shaft, 44... output shaft, 70... flywheel.

Claims

1. A drive actuator used in a drive actuator including a prime mover, a continuously variable transmission that changes the rotation input from the prime mover to an input shaft and outputs it to a driven device from an output shaft, and a transmission actuator that can change the transmission ratio of the continuously variable transmission, and a control device that controls the prime mover and the transmission actuator, When performing acceleration control to accelerate the driven device, a control device that performs first torque generation control to generate a negative torque that decelerates the input shaft and a positive torque that accelerates the output shaft in the continuously variable transmission by increasing the transmission ratio.

2. The control device according to claim 1, wherein the first torque generation control is performed after initial control of accelerating the prime mover with the transmission ratio of the continuously variable transmission substantially set to zero.

3. The control device according to claim 1, wherein when the prime mover is rotated by control of at least one of the prime mover and the transmission actuator performed before the start of the acceleration control, the first torque generation control is performed while the rotation of the prime mover by the control continues.

4. A drive actuator used in a drive actuator including a prime mover, a continuously variable transmission that changes the rotation input from the prime mover to an input shaft and outputs it to a driven device from an output shaft, and a transmission actuator that can change the transmission ratio of the continuously variable transmission, and a control device that controls the prime mover and the transmission actuator, When performing deceleration control to decelerate the driven device, a control device that performs second torque generation control to generate a positive torque that accelerates the input shaft and a negative torque that decelerates the output shaft in the continuously variable transmission by decreasing the transmission ratio.

5. When performing acceleration control to accelerate the driven device, the first torque generation control is performed to generate a negative torque that decelerates the input shaft and a positive torque that accelerates the output shaft in the continuously variable transmission by increasing the transmission ratio, The control device according to claim 4, wherein the first torque generation control is performed while the rotation of the prime mover by the second torque generation control continues.

6. The control device according to claim 4, wherein in the second torque generation control, the decrease in the transmission ratio is stopped before reaching a transmission ratio range in which the rotation of the driven device is locked.

7. A drive actuator including the control device according to any one of claims 1 to 6.

8. The drive actuator according to claim 7, comprising a flywheel attached to the drive shaft of the prime mover.

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