Control device and drive actuator

Abstract

Provided is a control device 20 that is used in a drive actuator 10 provided with a motor 14, a continuously variable transmission 16 which changes the speed of rotation input from the motor 14 to an input shaft and which outputs the rotation from an output shaft to a driven device 12, and a shift actuator 18 which is capable of changing the shift ratio of the continuously variable transmission 16, and that controls the motor 14 and the shift actuator 18, wherein, when acceleration control for accelerating the driven device is performed, the shift ratio is increased, thereby performing first torque generation control for generating, in the continuously variable transmission 16, negative torque for decelerating the input shaft and positive torque for accelerating the output shaft.

Description

Control device and drive actuator

[0001] The present disclosure relates to a control device for use in a drive actuator.

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

[0003] Japanese Patent Application Laid-Open No. 2020-205742

[0004] It may be advantageous to use a drive actuator if torque for accelerating or decelerating a driven device can be generated within the transmission, separate from the prime mover torque generated by the prime mover.

[0005] Therefore, one of the objects of the present disclosure is to provide a technology that can generate torque for accelerating or decelerating a driven device within a transmission, separate from the prime mover torque.

[0006] The control device disclosed herein is used in a drive actuator that includes a prime mover, a continuously variable transmission that changes the speed of the rotation input from the prime mover to an input shaft and outputs it from an output shaft to a driven device, and a speed change actuator that can change the gear ratio of the continuously variable transmission, and is a control device that controls the prime mover and the speed change actuator.When performing acceleration control to accelerate the driven device, the speed change ratio is increased to perform first torque generation control that generates a negative torque that decelerates the input shaft and a positive torque that accelerates the output shaft within the continuously variable transmission.

[0007] Another control device of the present disclosure is a control device used in a drive actuator including a prime mover, a continuously variable transmission that changes the speed of rotation input from the prime mover to an input shaft and outputs the rotation from an output shaft to a driven device, and a speed change actuator that can change the gear ratio of the continuously variable transmission, and controls the prime mover and the speed change actuator.When performing deceleration control to decelerate the driven device, the speed change ratio is reduced to perform second torque generation control to generate a positive torque that accelerates the input shaft and a negative torque that decelerates the output shaft within the continuously variable transmission.

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

[0009] FIG. 3(A) is a block diagram of a drive actuator of an embodiment. FIG. 3(B) is a side cross-sectional view of a continuously variable transmission of an embodiment. FIG. 3(A) is a first explanatory diagram relating to acceleration control, and FIG. 3(B) is a second explanatory diagram thereof. FIG. 3(A) is a first explanatory diagram relating to deceleration control, and FIG. 5(B) is a second explanatory diagram thereof. FIG. 3(B) is a schematic diagram explaining a flywheel.

[0010] Hereinafter, an embodiment for implementing the drive actuator of the present disclosure will be described. The same or equivalent elements will be given the same reference numerals, and duplicate explanations will be omitted. In each drawing, for the sake of convenience, components will be omitted, enlarged, or reduced as appropriate. The drawings should be viewed in accordance with the orientation of the reference numerals.

[0011] In this specification, the terms "first" and "second" are used only as a formal description to distinguish between multiple elements and do not have any other substantive meaning. For example, they do not limit the order of the elements to which these terms are attached. Furthermore, a "second" element may exist without a "first" element.

[0012] Referring to Fig. 1, a driving actuator 10 is used to drive a 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 rotational drive unit 12a that is rotationally driven by the driving actuator 10. The rotational drive unit 12a is, for example, a screw shaft used in the ball screw device. Specific examples of the driven device 12 are not particularly limited, and may be part of an industrial machine (machine tool, construction machine, etc.), a robot (industrial robot, service robot, etc.), transportation equipment (conveyor, vehicle, etc.), or the like.

[0013] The drive actuator 10 includes 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 the rotation from an output shaft to a driven device 12, a speed change actuator 18 that can change the gear ratio of the continuously variable transmission 16, and a control device 20 that controls the prime mover 14 and the speed change actuator 18. The drive actuator 10 also 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, 24 are configured with an encoder, a torque sensor, etc. The rotation detectors 22, 24 output detection results related to their own detection targets to the control device 20.

[0014] The prime mover 14 rotates a drive shaft (not shown) using torque generated internally (hereinafter referred to as "prime mover torque"), and can output the rotation from the drive shaft to the continuously variable transmission 16. The prime mover 14 in this embodiment is a motor (electric motor) that rotates the drive shaft using electrical energy. The motor can rotate the drive shaft using prime mover torque generated by cooperation between a stator and a rotor. There are no particular limitations on the specific example of the prime mover 14, and it may be, for example, an engine that rotates the drive shaft using thermal energy.

[0015] The speed change actuator 18 is able to change the gear ratio of the continuously variable transmission 16 by inputting power to the continuously variable transmission 16. The speed change actuator 18 of this 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 speed change actuator 18 is not particularly limited as long as it can change the gear ratio of the continuously variable transmission 16, and may be a rotary actuator or the like.

[0016] The control device 20 is configured by a combination of hardware elements and software elements, or by hardware elements only. Examples of hardware elements include a processor, a read-only memory (ROM), and a random access memory (RAM). Examples of software elements include an operating system, an application program, and the like. The portion used to control the prime mover 14 and the portion used to control the speed change actuator 18 may be realized by common hardware or software elements, or may be realized by separate hardware 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 speed change actuator 18.

[0018] The control device 20 controls the prime mover 14 and the speed change actuator 18 using power supplied from an external main power supply 26 or auxiliary power supply 28. When an abnormality detection device (not shown) detects that there is no abnormality (e.g., a power outage) in the main power supply 26, the control device 20 controls the prime mover 14 and the speed change actuator 18 using power supplied from the main power supply 26. When the abnormality detection device detects an abnormality in the main power supply 26, the control device 20 controls the prime mover 14 and the speed change actuator 18 using power supplied from the auxiliary power supply 28. In this embodiment, the acceleration control and deceleration control described below may be performed using power supplied from the main power supply 26.

[0019] 2, the continuously variable transmission 16 includes an input shaft 40 to which rotation is input from the prime mover 14, a speed change mechanism 42 that changes the speed of the rotation input to the input shaft 40 and then transmits it to an output shaft 44, an output shaft 44 that outputs the rotation transmitted from the speed change mechanism 42 to a driven device, and a speed ratio change mechanism 46 that changes the speed ratio of the speed change mechanism 42. The speed change mechanism 42 includes a plurality of friction transmission elements 48 (described below) that transmit rotation by friction. The 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 change the gear ratio continuously (infinitely) by using the gear ratio changing mechanism 46 via the gear actuator 18. The gear ratio here refers to the ratio of the ideal input rotational speed to the output rotational speed that can be achieved when there is no slippage between the multiple friction transmission elements 48. If the ideal input rotational speed and the ideal output rotational speed that can achieve this gear ratio are defined as the ideal input rotational speed and the ideal output rotational speed, respectively, the gear ratio is expressed as the ideal output rotational speed / ideal input rotational speed. Note that the input rotational speed here refers to the rotational speed of the input shaft 40, and the output rotational speed refers to the rotational speed of the output shaft 44.

[0021] The continuously variable transmission 16 of this embodiment is an infinitely variable transmission (IVT) with an infinitely large gear ratio, and is configured so that the variable range of the gear ratio includes zero (= 1 / ∞). Here, an example of such a continuously variable transmission 16 will be described, but the specific example is not particularly limited. For example, the continuously variable transmission 16 may be a toroidal continuously variable transmission or the like. Furthermore, the continuously variable transmission 16 may not include zero in the 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 is shown as being made up of multiple members, but it may also be made up of a single member, and the number of members is not particularly limited.

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

[0024] When the input bearing ring 50 rotates, the planetary rolling elements 60 rotate about the rotation axis L60 while revolving around the rotation axis L40 (revolution axis) of the input shaft 40. As the planetary rolling elements 60 revolve, the output bearing ring 58 rotates about the rotation axis L40 in response. Ideally, the output bearing ring 58 rotates at an output rotation speed obtained by multiplying the input rotation speed of the input bearing ring 50 by the gear ratio. This gear 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 gear ratio change mechanism 46.

[0025] The output shaft 44 includes an output bearing ring 58 and an output member 44a that is connected to the output bearing ring 58 for integral rotation and outputs rotation to the driven device 12. The specific structure of the output shaft 44 is not particularly limited as long as it can transmit rotation from the speed change mechanism 42 to the driven device 12. Here, the output shaft 44 is shown as being made up of multiple members, but it may also be made up of a single member, and the number of members is not particularly limited.

[0026] The gear ratio change mechanism 46 of this embodiment is able to change the gear ratio by changing the position of the input race 50. The gear ratio change mechanism 46 includes a shaft 46a that is movable in the axial direction by power output from the gear change actuator 18, and a ring member 46b that is movable in the axial direction integrally with the shaft 40b. The ring member 46b rotatably supports the input shaft 40 via a bearing 46c, and is able to move in the axial direction integrally with the input shaft 40 by a snap ring or the like. There are no particular limitations on the specific example of the gear ratio change mechanism 46, and various mechanisms similar to those employed in the continuously variable transmission 16 may be employed.

[0027] When an axial driving force is input from the speed change actuator 18 to the shaft 46a, the input shaft 40 (including the input race 50 and the first support race 52) moves axially together with the ring member 46b. The axial movement of the input race 50 and the first support race 52 relative to the second support race 56 and the output race 58 changes the inclination angle of the rotation axis L60 of the planetary rolling elements 60 relative to the rotation axis L40, changing the gear ratio according to that inclination angle. This gear ratio is zero (= 1 / ∞) when the rotation axis L60 is parallel to the rotation axis L40, and continuously increases as the inclination angle of the rotation axis L60 relative to the rotation axis L40 increases. In other words, the gear ratio can be changed continuously (steplessly), and its variable range includes zero.

[0028] Next, the underlying concept for explaining the control details of the control device 20 will be explained. The rotation, moment of inertia, angular acceleration, angular velocity, acceleration torque, and deceleration torque of the driven device 12 and the prime mover 14 described below refer to the entire object rotating in the referenced subject. For example, the acceleration torque of the prime mover 14 refers to the acceleration torque of the entire object (such as the prime mover shaft) rotating in the prime mover 14. Furthermore, the moment of inertia of the driven device 12 refers to the moment of inertia of the entire object (such as the rotational drive unit 12a) rotating in the driven device 12. Furthermore, the acceleration torque and deceleration torque here refer to the torque required to accelerate or decelerate the referenced subject.

[0029] At a certain time during acceleration of the driven device 12, the output torque T Ａ When J is output to the driven device 12, the following equation (1) is established. Ｌ is the moment of inertia of the driven device 12 (kg m 2 ), W Ｌ is the angular acceleration (rad / s 2 ), T Ｌ is the load torque (N·m) of the driven device 12. Ａ =J Ｌ ×W Ｌ +T Ｌ ...(1)

[0030] The prime mover 14 generates a prime mover torque T Ｍ When generating the signal, the following equation (2) holds: 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 ), Z is the speed ratio (-) of the continuously variable transmission 16. In this specification, the influence of the moment of inertia of the continuously variable transmission 16 is omitted because it is sufficiently small. In addition, the influence of viscosity, rigidity, and power loss in each part of the drive actuator 10 is also omitted. T Ｍ =J Ｍ ×W Ｍ +Z×T Ａ ... (2)

[0031] The following 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 seen from equation (3), the prime mover torque T Ｍ is usually the acceleration torque (J Ｍ ×W Ｍ ), the acceleration torque of the driven device 12 (Z×J Ｌ ×W Ｌ ), the load torque of the driven device 12 (Z×T Ｌ ) can be expressed as the sum of

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

[0034] Please refer to Fig. 3(A). Fig. 3(A) shows only the input shaft 40, the speed change mechanism 42, and the output shaft 44 of the continuously variable transmission 16. The same applies to the following Figs. 3(B), 4(A), and 4(B).

[0035] First, the speed change actuator 18 is controlled to set the speed ratio Z of the continuously variable transmission 16 to substantially zero, and the prime mover 14 is controlled to generate prime mover torque to accelerate the prime mover 14. In the initial control, the prime mover 14 is accelerated so that the angular velocity of the prime mover 14 becomes sufficiently high. At this time, the input shaft 40 of the continuously variable transmission 16 is also accelerated in the same manner. In order to generate prime mover torque while maintaining the speed ratio Z at 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, T can be expressed by the following equation (4) using equation (3). Ｍ =J Ｍ ×W Ｍ ...(4)

[0036] See Fig. 3(B). Next, with the prime mover 14 rotating at a sufficiently high angular velocity, first torque generation control is performed to continuously increase the gear ratio from substantially zero by controlling the speed change actuator 18. This first torque generation control can be performed in two cases: with the prime mover torque of the prime mover 14 set to zero (control example 1), and with prime mover torque being generated by the prime mover 14 (control example 2). First, control example 1 will be described. Hereinafter, the rotational direction D40 of the input shaft 40 will be referred to as the forward rotational direction, and the rotational direction opposite thereto will be referred to as the reverse rotational direction.

[0037] (Control Example 1) The actual output rotation speed of the output shaft 44 relative to the actual input rotation speed of the input shaft 40 is called the actual rotation speed ratio (= actual output rotation speed / actual input rotation speed). In this first torque generation control, the gear ratio is increased so that the gear ratio (= ideal output rotation speed / ideal input rotation speed) is larger than the actual rotation speed ratio when the first torque generation control is started. When the first torque generation control is started, the prime mover 14 is rotated while the output shaft 44 of the continuously variable transmission 16 is stopped by initial control, so the actual rotation speed ratio also becomes zero. For this reason, when the first torque generation control is started, the gear ratio is always larger than the actual rotation speed ratio.

[0038] When the speed ratio (= ideal output speed / ideal input speed) is greater than this actual rotation speed ratio (= actual output speed / actual input speed), slippage occurs between the friction transmission elements 48 of the continuously variable transmission 16. When the speed ratio is greater than the actual rotation speed ratio, a friction transmission element (input raceway 50 in this embodiment) that is rotatable integrally with the input shaft 40 experiences slippage S1 in the forward rotation direction relative to an adjacent friction transmission element (planetary rolling element 60 in this embodiment) on the output side. Furthermore, a friction transmission element (output raceway 58 in this embodiment) that is rotatable integrally with the output shaft 44 experiences slippage S2 in the reverse rotation direction relative to an adjacent friction transmission element (planetary rolling element 60 in this embodiment) on the input side. At the same time, a reaction torque is generated in the input shaft 40 and the output shaft 44 as a reaction to the slippage in a direction that resists the slippage. At this time, a negative torque F1 in the opposite direction (reverse rotation direction) to the slip S1 is generated on the input shaft 40 as a reaction torque, and a positive torque F2 in the opposite direction (positive rotation direction) to the slip S2 is generated on the output shaft 44 as a reaction torque.

[0039] In this way, in the first torque generation control, by increasing the gear ratio while the prime mover 14 is rotating, it is possible to generate opposing negative torque F1 and positive torque F2 in the continuously variable transmission 16 due to slippage in the continuously variable transmission 16. In other words, in the first torque generation control, the gear ratio is increased so as to generate, in the continuously variable transmission, negative torque F1 that decelerates the input shaft 40 and positive torque F2 that accelerates the output shaft 44. To achieve this, it is a prerequisite that the gear ratio is increased until it becomes larger than the actual rotation speed ratio at the time 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 actual rotation speed ratio (= actual output rotation speed / actual input rotation speed) mentioned above gradually increases. After the increase in the speed ratio is stopped, when the actual rotation speed ratio increases to the speed ratio, the load torque T of the driven device 12 ＬA negative torque F1 and a positive torque F2 that are balanced with the load torque T of the driven device 12 due to friction, etc. are generated in the continuously variable transmission 16. Ｌ As a result, the driven device 12, prime mover 14, and continuously variable transmission 16 (including input shaft 40 and output shaft 44) decelerate while maintaining the actual rotation speed ratio at the gear ratio. The above operation can be considered as generating an output torque (positive torque F2) of the drive actuator 10 using the kinetic energy stored in the prime mover 14, thereby converting the kinetic energy of the prime mover 14 into kinetic energy of the driven device 12.

[0041] When a negative torque F1 and a positive torque F2 are generated in the continuously variable transmission 16, the output torque T of the drive actuator 10 at a certain time is Ａ can be expressed by the following equation (5) from the above equation (2). Ｍ becomes zero, so T in equation (2) Ｍ The term becomes zero. Ａ = -(1 / Z)J Ｍ ×W Ｍ ...(5)

[0042] The first term on the right side of equation (5) represents the positive torque F2 due to slippage. Ｍ <0, and the first term is positive. Ａ >0, and the output torque T Ａ It can be seen that the driven device 12 can be accelerated by

[0043] (Control Example 2) Next, control example 2 will be described. In control example 2, under the condition that prime mover torque is generated by the prime mover 14 through control of the prime mover 14, first torque generation control is performed to increase the speed ratio through control of the speed change actuator 18, thereby generating a negative torque F1 on the input shaft 40 and a positive torque F2 on the output shaft 44 within the continuously variable transmission 16. At this time, prime mover torque in the positive rotation direction D40 is generated by the prime mover 14. At this time, the output torque T of the drive actuator 10 Ａ can be expressed by the following equation (6) from the above equation (2): Ａ = TＭ / Z-(1 / Z)J Ｍ ×W Ｍ ...(6)

[0044] As can be seen from the comparison with equation (5), the output torque T Ａ is the prime mover torque T of the prime mover 14, while the second term on the right side indicates the positive torque F2 due to slippage. Ｍ (positive) by the speed ratio Z (positive). Ｍ < 0, and the second term is positive. Therefore, compared to the case of control example 1 in which the prime mover torque is set to zero, the output torque T Ａ This means that we can increase the size of the system.

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

[0047] Next, a specific operation of the acceleration control performed by the control device 20 will be described. Here, an operation will be described when acceleration control is performed to accelerate the stopped driven device 12. As described above, this acceleration control is performed in the order of initial control → first torque generation control.

[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 acceleration condition is satisfied and the second rotation detector 24 detects that the rotation drive unit 12a of the driven device 12 or the output shaft 44 of the continuously variable transmission 16 has stopped rotating.

[0049] The control device 20 controls the speed change actuator 18 to set the speed ratio Z of the continuously variable transmission 16 to substantially zero, and then controls the prime mover 14 to generate prime mover torque, thereby performing initial control to accelerate the prime mover 14. Here, "substantially zero" includes not only mathematically strict zero and 1 / ∞, but also values ​​close to zero that are very small compared to speed ratios used in general power transmission applications. This "substantially zero" includes, for example, a value that is 1 / 1000 or less in terms of speed ratio.

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

[0052] The target angular velocity of prime mover 14 in the initial control and the target gear ratio of continuously variable transmission 16 in the first torque generation control may be set according to the target angular velocity to be achieved by driven device 12, which is set in control device 20. Specifically, the angular velocity of driven device 12, which is accelerated using positive torque F2 due to slippage generated by first torque generation control, is correlated with the target angular velocity of prime mover 14 in the initial control and the target gear ratio of continuously variable transmission 16. The faster the target angular velocity of prime mover 14 in the initial control, the faster the angular velocity of driven device 12 after acceleration, and the larger the target gear ratio, the faster the angular velocity of driven device 12 after acceleration. Therefore, relational information, such as a relational equation or table, indicating these correlations may be stored in advance in a storage unit, and the target angular velocity of prime mover 14 and the target gear ratio of continuously variable transmission 16 that can achieve the target angular velocity may be set based on the relational information and the target angular velocity of driven device 12.

[0053] After the speed ratio is increased by the first torque generation control and the increase is stopped, the actual rotation speed ratio increases until it becomes equal to the speed ratio, and then, as described above, the load torque T Ｌ A state in which a negative torque F1 and a positive torque F2 that balance with the actual rotation speed ratio are generated within the continuously variable transmission 16. If the driven device 12 has not yet reached the target angular velocity when the actual rotation speed ratio increases to match the gear ratio, a prime mover torque may be generated to accelerate the driven device 12 until the driven device 12 reaches the target angular velocity. In this case, it is necessary to determine whether the actual rotation speed ratio matches the gear ratio. This determination may be based on, for example, 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 calculated from the detected values ​​of the input rotation speed and the output rotation speed, and it may be determined that the actual rotation speed ratio matches the gear ratio when the actual rotation speed ratio approximately matches the gear ratio.

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

[0055] In the first torque generation control, when torques F1 and F2 due to slip are generated within the continuously variable transmission 16, it is not necessary to generate a prime mover torque for accelerating the driven device 12, as in the above-mentioned control example 1, or it is possible to generate the prime mover torque, as in the above-mentioned control example 2.

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

[0057] When performing acceleration control, the control device 20 increases the gear ratio to perform first torque generation control that generates, within the continuously variable transmission 16, a negative torque F1 that decelerates the input shaft 40 and a positive torque F2 that accelerates the output shaft 44. This makes it possible to generate, in addition to the prime mover torque, a positive torque F2 for accelerating the driven device 12 within the continuously variable transmission 16.

[0058] 4 is a diagram showing the difference in torque generated between the conventional example and control examples 1 and 2. In the conventional example, the sum 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] In Control Example 1, the positive torque F2 caused by slippage generated by the first torque generation control covers the total of the acceleration torque and load torque of the driven device 12. In Control Example 1, when the positive torque F2 is generated, the acceleration torque of the prime mover 14 becomes zero. Furthermore, when accelerating the prime mover 14 by initial control, the prime mover torque that needs to be covered by the prime mover 14 is only the acceleration torque of the prime mover 14. In other words, 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 is not necessary 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 downsizing the prime mover 14.

[0060] In control example 2, in order to cover the total of the acceleration torque and load torque of the driven device 12, in addition to the positive torque F2 caused by slippage generated by the first torque generation control, prime mover torque is added. This is advantageous in increasing the output torque of the driving actuator 10 for accelerating the driven device 12 without having to increase the size of the prime mover 14. Furthermore, 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] Furthermore, the control device 20 performs initial control to accelerate the prime mover 14 with the speed ratio of the continuously variable transmission 16 set to substantially zero, and then performs first torque generation control. Therefore, the initial control allows the prime mover 14 to accelerate without generating load torque or acceleration torque in the driven device 12, effectively increasing the kinetic energy of the prime mover 14. The increased kinetic energy of the prime mover 14 can be converted into kinetic energy of the driven device 12 by the first torque generation control, allowing the driven device 12 to accelerate effectively.

[0062] Furthermore, when starting the driven device 12 that is stopped, the drive actuator 10 must output an output torque that overcomes the static friction force acting on the driven device. The output torque required to start the driven device is greater than the output torque required while the driven device 12 is in operation. If the output torque required for starting were to be provided solely by prime mover torque, the prime mover torque required of the prime mover 14 would increase, resulting in an increase in the size of the prime mover 14. According to this embodiment, the first torque generation control is performed after the initial control, and the positive torque F2 generated in the continuously variable transmission 16 is used to start the driven device 12 that is stopped. Therefore, the output torque required to start the driven device 12 can be provided using a source other than prime mover torque, thereby reducing the prime mover torque required of the prime mover 14 and contributing to a smaller prime mover 14.

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

[0064] See Fig. 5(A). In the deceleration control, second torque generation control is performed to continuously reduce the gear ratio while the driven device 12 and the prime mover 14 are rotating. The second torque generation control is performed while the input shaft 40 and output shaft 44 of the continuously variable transmission 16 are rotating. In this second torque generation control, the gear ratio is reduced so that it becomes smaller than the actual rotation speed ratio when the second torque generation control was started.

[0065] 5B . When the speed ratio is smaller than the actual rotation speed ratio, a friction transmission element (input race 50 in this embodiment) that is rotatable integrally with input shaft 40 experiences slippage S3 in the reverse rotation direction relative to an adjacent friction transmission element (planetary rolling element 60 in this embodiment) on the output side. Furthermore, a friction transmission element (output race 58 in this embodiment) that is rotatable integrally with output shaft 44 experiences slippage S4 in the forward rotation direction relative to an adjacent friction transmission element 48 (planetary rolling element 60 in this embodiment) on the input side. At the same time, a positive torque F3 in the opposite direction (forward rotation direction) to slippage S3 is generated on input shaft 40 as a reaction torque, and a negative torque F4 in the opposite direction (reverse rotation direction) to slippage S4 is generated on output shaft 44 as a reaction torque.

[0066] In this way, in the second torque generation control, by reducing the gear ratio while the driven device 12 is rotating, it is possible to generate opposing positive torque F3 and negative torque F4 within the continuously variable transmission 16 due to slippage within the continuously variable transmission 16. In other words, in the second torque generation control, the gear ratio is reduced so as to generate, within the continuously variable transmission 16, a positive torque F3 that accelerates the input shaft 40 and a negative torque F4 that decelerates the output shaft 44. To achieve this, it is a prerequisite that the gear ratio is reduced until it becomes smaller than the actual rotation speed ratio at the time 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 rotational speed of the input shaft 40 increases and the actual output rotational speed of the output shaft 44 decreases, gradually decreasing the actual rotational speed ratio (= actual output rotational speed / actual input rotational speed). After the reduction in the gear ratio is stopped, when the actual rotational speed ratio decreases to the gear ratio, the positive torque F3 and negative torque F4 caused by slippage in the continuously variable transmission 16 no longer occur in the continuously variable transmission 16. The above operation can be considered as generating a reverse drive torque (positive torque F3) for the prime mover 14 by utilizing the kinetic energy stored in the driven device 12, thereby converting the kinetic energy of the driven device 12 into kinetic energy of the prime mover 14.

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

[0069] When performing deceleration control, the control device controls the speed change actuator 18 to perform second torque generation control, which continuously reduces the gear ratio, while the driven device 12 is rotating. To achieve this, the gear ratio of the continuously variable transmission 16 may be reduced until it falls below the target upper limit gear ratio. At this time, the lower limit value of the gear ratio becomes zero. In this case, the second torque generation control stops reducing the gear ratio when the gear ratio of the continuously variable transmission 16 falls below the target upper limit gear ratio.

[0070] When the gear ratio of the continuously variable transmission 16 becomes very small, the rotation of the driven device 12 is locked when slippage between the friction transmission elements 48 within the continuously variable transmission 16 begins to cease. "Locked" here refers to a state in which the driven device 12 does not move at all or moves very little when the user tries to rotate it. The gear ratio range in which the rotation of the driven device 12 is locked in this way is called the locked gear ratio range. This locked gear ratio range is, for example, from zero (= 1 / ∞) to approximately 1 / several hundredths.

[0071] In the second torque generation control, the gear ratio may be reduced until the locked gear ratio range is reached, thereby allowing the driven device 12 to stop without generating prime mover torque for decelerating the driven device 12.

[0072] Furthermore, if the speed ratio is reduced to the lock speed ratio range in the second torque generation control, a sudden stop of rotation of the driven device 12 may cause a large impact load to occur within the continuously variable transmission 16. Therefore, in the second torque generation control, the reduction of the speed ratio may be stopped before the lock speed ratio range is reached. This prevents the occurrence of an impact load due to a sudden stop of rotation of the driven device 12. In this case, when performing deceleration control, it is preferable to stop the reduction of the speed ratio before the lock speed ratio range is reached and then generate prime mover torque by the prime mover 14 to decelerate the driven device 12. This prime mover torque may be generated until the rotation of the driven device 12 stops. This allows the second torque generation control to decelerate the driven device 12 while avoiding a sudden stop of the driven device 12, and the prime mover torque of the prime mover 14 can also be used to slowly stop the driven device 12.

[0073] In the second torque generation control, when torques F3 and F4 due to slip are generated in continuously variable transmission 16 by reducing the gear ratio, it is not necessary to generate prime mover torque for decelerating driven device 12, as in the above-described control example 1. Alternatively, the prime mover torque may be generated, as in control example 2.

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

[0075] When performing deceleration control, the control device 20 can perform second torque generation control by reducing the gear ratio to generate, within the continuously variable transmission 16, a positive torque F3 that accelerates the input shaft 40 and a negative torque F4 that decelerates the output shaft 44. This makes it possible to generate, within the continuously variable transmission 16, a negative torque F4 for decelerating the driven device 12, separate from the prime mover torque.

[0076] When decelerating the driven device 12, it is usually necessary to generate a deceleration torque of the prime mover 14 and a deceleration torque of the driven device 12. When decelerating the driven device 12 using only the negative torque F4 generated within 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 with only the prime mover torque. This allows the load on the prime mover to be reduced when decelerating the driven device, which is advantageous for making the prime mover smaller.

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

[0078] Next, other control details by the control device 20 will be described. The first torque generation control used for acceleration control and the second torque generation control used for deceleration control described above may be combined. For example, the positive torque F3 generated in the continuously variable transmission 16 by the second torque generation control used for deceleration control causes the prime mover 14 to rotate at high speed. When the prime mover 14 is thus rotated by the second torque generation control for the prime mover 14, etc., the first torque generation control may be performed while the prime mover 14 continues to rotate by that control in order to perform acceleration control by the control device 20. In other words, the first torque generation control may be performed before the rotation of the prime mover 14 by that control stops.

[0079] This makes it possible to accelerate the driven device 12 by utilizing the kinetic energy stored in the prime mover 14 by the previous control (here, the second torque generation control) of the prime mover 14, etc. Compared to when the kinetic energy used to accelerate the driven device 12 is regenerated by the prime mover torque after the previous control of the prime mover 14, etc., energy consumption by the prime mover 14 is reduced, improving the energy saving of the drive actuator 10. In particular, when the second torque generation control is performed before the start of acceleration control, it becomes easier to rotate the prime mover 14 at high speed, which makes it easier to store large kinetic energy in the prime mover 14, and the driven device 12 can be effectively accelerated by the first torque generation control.

[0080] From the perspective of improving the energy saving of the drive actuator 10, when the prime mover 14 is rotated by the control of at least one of the prime mover 14 and the speed change actuator 18 by the control device 20 before the start of the acceleration control, the first torque generation control can be performed while the rotation of the prime mover 14 continues due to that control. Here, the second torque generation control is exemplified as the "control of the control device 20 performed before the start of the acceleration control," but the specific example of this control is not limited to this. For example, the control device 20 may perform constant speed control to maintain the driven device 12 in a constant speed state. Furthermore, when this control is the second torque generation control, when prime mover torque for decelerating the driven device 12 is not generated as described above, only control to reduce the gear ratio of the speed change actuator 18 is performed. On the other hand, when prime mover torque for decelerating the driven device 12 is generated as described above, control of both the speed change actuator 18 and the prime mover 14 is performed.

[0081] Furthermore, at this time, during the waiting period from when the control device 20 completes control of the prime mover 14 and the like before the start of acceleration control until the start of the first torque generation control, the prime mover 14 should be controlled so as not to apply a torque that brakes the prime mover 14, in order to maintain the rotation state of the prime mover 14. Even if the drive actuator 10 is equipped with a braking device that brakes the prime mover 14, it is preferable to control the braking device so that no braking torque is applied by the braking device during the waiting period.

[0082] Next, a modified example of the drive actuator 10 will be described with reference to Fig. 6. The prime mover 14 includes a prime mover shaft 14a and a prime mover housing 14b from which the prime mover shaft 14a protrudes.

[0083] The drive actuator 10 of this embodiment includes a flywheel 70 attached to the driving shaft 14a. The flywheel 70 rotates together with the driving shaft 14a of the prime mover 14, thereby increasing the moment of inertia of the entire rotation system. The attachment position of the flywheel 70 relative to the driving shaft 14a is not particularly limited. Here, an example is shown in which the flywheel 70 is attached to a counter-load side portion of the driving shaft 14a that protrudes from the driving motor housing 14b toward the counter-load side (the side opposite the continuously variable transmission 16). Alternatively, as indicated by the two-dot chain line, the flywheel 70 may be attached to a load side portion of the driving shaft that protrudes from the driving motor housing 14b toward the load side (the continuously variable transmission 16 side).

[0084] As a result, when the acceleration control described above is performed, the kinetic energy of the flywheel 70 can be converted into the kinetic energy of the driven device 12 in addition to the kinetic energy of the prime mover 14, which is advantageous for accelerating the driven device 12. Furthermore, when the deceleration control described above is performed, 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 decelerating the driven device 12.

[0085] The above-described embodiments are merely examples. The abstract technical concepts should not be interpreted as being limited to the content of the embodiments. Many design changes are possible within the content of the embodiments, such as changes, additions, and deletions of components. In the above-described embodiments, the terms "this embodiment" and "embodiment" are used to emphasize content that allows such design changes. However, design changes are also permitted even in content without such notation. Hatching on cross sections in the drawings does not limit the material of the hatched object. Furthermore, mutual substitution of any of the components and expressions of the present disclosure between methods, devices, systems, etc. is also valid as an aspect of the present disclosure.

[0086] The present disclosure relates to a control device for use in a drive actuator.

[0087] 10... driving actuator, 12... driven device, 14... prime mover, 14a... prime mover shaft, 16... continuously variable transmission, 18... speed change actuator, 20... control device, 40... input shaft, 44... output shaft, 70... flywheel

Claims

1. A control device used for 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, the control device controlling the prime mover and the transmission actuator, and when performing acceleration control to accelerate the driven device, performing first torque generation control for generating a negative torque for decelerating the input shaft and a positive torque for accelerating the output shaft in the continuously variable transmission by increasing the transmission ratio.

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

3. The control device according to claim 1 or 2, 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 control device used for 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, the control device controlling the prime mover and the transmission actuator, and when performing deceleration control to decelerate the driven device, performing second torque generation control for generating a positive torque for accelerating the input shaft and a negative torque for decelerating the output shaft in the continuously variable transmission by decreasing the transmission ratio.

5. When performing acceleration control to accelerate the driven device, performing first torque generation control for generating a negative torque for decelerating the input shaft and a positive torque for accelerating the output shaft in the continuously variable transmission by increasing the transmission ratio, and performing the first torque generation control while the rotation of the prime mover by the second torque generation control continues. The control device according to claim 4.

6. In the second torque generation control, the control device according to claim 4 or 5, wherein 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, further comprising a flywheel attached to the drive shaft of the prime mover.

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