Continuously variable transmission system, continuously variable transmission, and method for controlling continuously variable transmission system

Abstract

A continuously variable transmission system 100 comprises: a continuously variable transmission 2 which has a rolling element and a bearing ring coming into contact with the rolling element, and which changes the speed of rotation of an input shaft 22 and outputs the same to an output shaft 25; a drive source which inputs the rotation to the input shaft 22; an input shaft control unit 10 which controls the rotation of the input shaft 22 through the drive source; a gear ratio change device 31 which changes the gear ratio of the continuously variable transmission 2; a gear ratio control unit 30 which controls gear ratio through the gear ratio change device 31; an output shaft information detection unit 16 which detects rotation information of the output shaft 25; and a command signal feed unit 50 which feeds a gear ratio command signal P1 to the gear ratio control unit 30 and feeds a rotation command signal S1 to the input shaft control unit 10 on the basis of an output command signal related to the output shaft 25 and a detection result F1 of the output shaft information detection unit 16.

Description

Continuously variable transmission system, continuously variable transmission, and control method for continuously variable transmission system

[0001] The present disclosure relates to a continuously variable transmission system, a continuously variable transmission, and a method for controlling a continuously variable transmission system.

[0002] A continuously variable transmission capable of an infinitely large gear ratio, known as an IVT (Infinitely Variable Transmission), is known. The present applicant disclosed in Patent Document 1 a friction transmission device including an input raceway, planetary rolling elements, and an output raceway. In this device, the planetary rolling elements are arranged around the rotation axis of the input raceway and contact the input raceway, while the output raceway is in contact with the planetary rolling elements and connected to an output shaft. This device also has a plurality of support raceways in contact with the planetary rolling elements, and changes the speed of rotation input to the input raceway and outputs it from the output shaft.

[0003] International Publication No. 2021 / 182001

[0004] The inventors of the present invention have come to the following realization regarding continuously variable transmissions. The continuously variable transmission described in Patent Document 1 is equipped with a traction mechanism that transmits rotation between contacting members, and therefore generates relative slippage in angular velocity, where the output shaft angular velocity is smaller than the result of multiplying the input shaft angular velocity by the gear ratio. This relative slippage in angular velocity has been a bottleneck in controlling the output of the continuously variable transmission with high precision.

[0005] The present disclosure has been made in consideration of such problems, and one of its objects is to provide a continuously variable transmission system that is capable of controlling the output of a continuously variable transmission with high precision.

[0006] In order to solve the above problems, a continuously variable transmission system according to one embodiment of the present disclosure includes a continuously variable transmission having rolling elements and raceways in contact with the rolling elements, which changes the rotation of an input shaft and outputs it to an output shaft, a drive source which inputs rotation to the input shaft, an input shaft control unit which controls the rotation of the input shaft through the drive source, a gear ratio change device which changes the gear ratio of the continuously variable transmission, a gear ratio control unit which controls the gear ratio through the gear ratio change device, an output shaft information detection unit which detects rotation information of the output shaft, and a command signal supply unit which supplies a gear ratio command signal to the gear ratio control unit and a rotation command signal to the input shaft control unit based on an output command signal related to the output shaft and the detection result of the output shaft information detection unit.

[0007] Another aspect of the present disclosure is a continuously variable transmission that has rolling elements and bearing rings in contact with the rolling elements, changes the speed of rotation of an input shaft, and outputs the rotation to an output shaft, and the gear ratio of the continuously variable transmission and the rotation of the input shaft are controlled based on an output command signal related to the rotation of the output shaft and rotation information of the output shaft.

[0008] Yet another aspect of the present disclosure is a control method for a continuously variable transmission system including a continuously variable transmission having rolling elements and bearing rings in contact with the rolling elements, which changes the speed of rotation of an input shaft and outputs the rotation to an output shaft, and a gear ratio change device which changes the gear ratio of the continuously variable transmission, the method including detecting rotation information of the output shaft, and controlling the gear ratio of the continuously variable transmission and the rotation of the input shaft based on an output command signal related to the rotation of the output shaft and the rotation information.

[0009] Any combination of the above components, or mutual substitution of the components or expressions of the present disclosure between methods, systems, etc., are also valid aspects of the present disclosure.

[0010] According to the present disclosure, it is possible to provide a continuously variable transmission system that is capable of controlling the output of a continuously variable transmission with high precision.

[0011] Fig. 3 is a block diagram showing a continuously variable transmission system of a first embodiment. Fig. 4 is a longitudinal sectional view showing the configuration of the continuously variable transmission of Fig. 1. Fig. 5 is a diagram showing an example of the relationship between relative slip of angular velocity and output shaft torque of the continuously variable transmission of Fig. 2. Fig. 6 is a diagram showing an example of the relationship between the speed ratio of the continuously variable transmission of Fig. 2 and the angular velocity of the input shaft. Fig. 7 is a block diagram showing a continuously variable transmission system of a second embodiment. Fig. 8 is a block diagram showing a continuously variable transmission system of a third embodiment.

[0012] The present disclosure will be described below based on preferred embodiments with reference to the drawings. In the embodiments and modified examples, identical or equivalent components and members are designated by the same reference numerals, and redundant explanations will be omitted where appropriate. Furthermore, the dimensions of the members in each drawing are enlarged or reduced as appropriate for ease of understanding. Furthermore, some members that are not important for explaining the embodiments are omitted from the drawings.

[0013] Furthermore, terms including ordinal numbers such as first and second are used to describe various components, but these terms are used only to distinguish one component from another and do not limit the components.

[0014] 1 to 4, a continuously variable transmission system 100 according to a first embodiment of the present disclosure will be described. Fig. 1 is a block diagram of the continuously variable transmission system 100. Fig. 2 is a vertical cross-sectional view showing the configuration of a continuously variable transmission 2.

[0015] The continuously variable transmission system 100 controls the output rotation of the continuously variable transmission 2, which drives the driven device 27, based on a torque command signal C1 provided from outside the system. Note that the torque command signal C1, along with an angular velocity command signal J1 and an angular position command signal K1, which will be described later, may be collectively referred to as an output command signal. For ease of explanation, in FIG. 2 , the axial direction of the continuously variable transmission 2 is simply referred to as the "axial direction," the right side of the axial direction is referred to as the input side, and the opposite side is referred to as the anti-input side.

[0016] 1, continuously variable transmission system 100 mainly includes a continuously variable transmission 2, a motor 11, an input shaft control unit 10, a gear ratio changing device 31, a gear ratio control unit 30, a command signal supply unit 50, an input shaft information detection unit 14, an output shaft information detection unit 16, and a gear ratio input detection unit 35. Continuously variable transmission system 100 of this embodiment controls the output torque of continuously variable transmission 2 so that it approaches a given target value.

[0017] 1, 5, and 6 can be realized in terms of hardware by elements such as a computer processor, CPU, and memory, electronic circuits, and mechanical devices, and in terms of software by computer programs, etc., but the functional blocks shown here are those realized by the cooperation of these elements. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms by combining hardware and software. In this embodiment, the input shaft control unit 10, the gear ratio control unit 30, the command signal supply unit 50, and the angular velocity control unit 60 and angular position control unit 62, which will be described later, are realized mainly by the CPU and its programs.

[0018] The drive source is not limited as long as it can input rotation to the input shaft 22, and in this example, is exemplified by a motor 11. The motor 11 inputs rotation to the input shaft 22 of the continuously variable transmission 2. The continuously variable transmission 2 changes the speed of the rotation input to the input shaft 22 and outputs it to the output shaft 25. The continuously variable transmission 2 has a transmission mechanism 24 including a traction mechanism having rolling elements 41 and raceways that contact the rolling elements 41. The rolling elements 41 in this embodiment are planetary rolling elements that revolve while rotating on their own axes. For example, the continuously variable transmission 2 drives a driven device 27 by the rotation of the output shaft 25.

[0019] The continuously variable transmission 2 has a gear ratio input unit 26 that receives power for changing the gear ratio of the transmission mechanism 24. This power changes the axial position of the gear ratio input unit 26, thereby changing the gear ratio. A gear ratio change device 31 outputs power to the gear ratio input unit 26 to change the gear ratio of the continuously variable transmission 2. A gear ratio control unit 30 controls the gear ratio through the gear ratio change device 31. Note that the gear ratio of the transmission mechanism 24 referred to in this specification refers to an ideal gear ratio defined from the mechanical dimensions of the components of the transmission mechanism 24. The actual gear ratio is affected by relative slippage of angular velocity, which will be described later, and therefore deviates slightly from the ideal gear ratio.

[0020] The input shaft information detection unit 14 detects rotation information related to the rotation of the input shaft 22 and outputs the detection result as input side information F2. The rotation of the input shaft 22 is also the output rotation of the motor 11. The output shaft information detection unit 16 detects rotation information related to the rotation of the output shaft 25 and outputs the detection result as detection result F1. The rotation of the output shaft 25 is also the input rotation of the driven device 27. Examples of rotation information include the angular velocity and angular position of the input shaft 22 and the output shaft 25. In this example, the detection result F1 is the angular velocity of the output shaft 25. The gear ratio input detection unit 35 detects the physical quantity output by the gear ratio change device 31 to the gear ratio input unit 26 and outputs the detection result as gear ratio information F3.

[0021] In this embodiment, the input shaft information detector 14, the output shaft information detector 16, and the gear ratio input detector 35 are rotary encoders capable of detecting the angular position and angular velocity of the rotating shaft. These detectors may be configured with different types of sensors or may be configured with the same type of sensor.

[0022] The command signal supply unit 50 generates a rotation command signal S1 and a gear ratio command signal P1 based on a torque command signal C1 related to the torque of the output shaft 25 provided by a higher-level means and the detection result F1 of the output shaft information detection unit 16. The command signal supply unit 50 supplies the generated rotation command signal S1 to the input shaft control unit 10 and supplies the generated gear ratio command signal P1 to the gear ratio control unit 30. The higher-level means is not limited as long as it is an element capable of generating the torque command signal C1, and may be, for example, a higher-level control element. The higher-level means may be provided within the continuously variable transmission system 100. The torque command signal C1 related to the torque of the output shaft 25 may be a target value of the torque of the output shaft 25, and the detection result F1 may be a feedback value.

[0023] The input shaft control unit 10 is an angular velocity control unit that controls the angular velocity of the input shaft 22, and provides motor drive power S3 to the motor 11 based on the rotation command signal S1. The motor 11 rotates based on the motor drive power S3, and inputs the rotation to the input shaft 22. In other words, the input shaft control unit 10 controls the angular velocity of the input shaft 22 through the motor 11.

[0024] The input shaft control unit 10 of the embodiment includes a motor control unit 13 and a motor drive unit 12. The motor control unit 13 compares the angular velocity of the input shaft 22 calculated from the input-side information F2 with the rotation command signal S1, and provides a motor control signal S2 generated based on the result to the motor drive unit 12. As an example, the motor control unit 13 may be a PI controller. The motor drive unit 12 supplies motor drive power S3 to the motor 11 based on the motor control signal S2. As an example, the motor drive unit 12 may be a three-phase inverter.

[0025] Based on the gear ratio command signal P1, the gear ratio control unit 30 provides device drive power P3 to the gear ratio changing device 31. The gear ratio changing device 31 changes the axial position of the gear ratio input unit 26 based on the device drive power P3, thereby changing the gear ratio of the continuously variable transmission 2. In other words, the gear ratio control unit 30 controls the gear ratio of the continuously variable transmission 2 through the gear ratio changing device 31.

[0026] The gear ratio control unit 30 of this embodiment has a device control unit 33 and a device drive unit 32. The device control unit 33 compares the axial position of the gear ratio input unit 26, calculated from the gear ratio information F3, with the gear ratio command signal P1, and provides a device control signal P2 generated based on the result to the device drive unit 32. The device drive unit 32 supplies device drive power P3 to the gear ratio changing device 31 based on the device control signal P2. As an example, the device drive unit 32 may be a three-phase inverter.

[0027] The gear ratio change device 31 may be of any type, as long as it can change the gear ratio of the continuously variable transmission 2. For example, a linear actuator or a rotary actuator may be used as the gear ratio change device 31. The gear ratio change device 31 of the embodiment is a device that combines a rotary actuator with a motion conversion mechanism that converts rotational motion into linear motion, and inputs power along the axial direction of the continuously variable transmission 2 to the gear ratio input unit 26 of the continuously variable transmission 2. The gear ratio change device 31 may use a device based on a known principle, such as a servo motor, a stepping motor, or an ultrasonic motor, as the rotary actuator. The gear ratio change device 31 may use a mechanism based on a known principle, such as a ball screw, a rack and pinion, or a cam, as the motion conversion mechanism. The rotary actuator and the motion conversion mechanism may be connected via a known transmission mechanism, such as a gear, a chain, or a belt.

[0028] The motor 11 in this embodiment is an electric motor that uses electrical energy to rotate a motor shaft (not shown). The motor 11 rotates the motor shaft using torque generated by the cooperation of a stator (not shown) and a rotor (not shown), and outputs the rotation from the motor shaft to the continuously variable transmission 2. There are no limitations on the type of motor 11, and in this example, it is a servo motor. The motor 11 may be, for example, a DC motor or an AC motor other than a servo motor.

[0029] The following describes the general operation of the continuously variable transmission 2. The continuously variable transmission 2 includes an input shaft 22, a transmission mechanism 24, and a gear ratio change mechanism 23. Rotation to be changed is input from the motor 11 to the input shaft 22. The transmission mechanism 24 changes the speed of the rotation input to the input shaft 22 and then transmits it to an output shaft 25. The continuously variable transmission 2 outputs the rotation, the speed of which has been changed by the transmission mechanism 24, from the output shaft 25 to a driven device 27. The gear ratio change mechanism 23 changes the gear ratio of the transmission mechanism 24.

[0030] Hereinafter, the rotation of the motor 11 refers to the rotation of an object rotating in the motor 11, and in this example refers to the rotation of the output shaft of the motor 11. Furthermore, the rotation of the driven device 27 refers to the rotation of an object rotating in the driven device 27.

[0031] A specific configuration of the continuously variable transmission 2 of this embodiment will be described. The continuously variable transmission 2 can change the actual speed ratio, which is the actual speed ratio, steplessly or continuously using the speed ratio changing device 31 and the speed ratio changing mechanism 23. The speed ratio here refers to the ratio of the output angular velocity, which is the angular velocity of the output shaft 25, to the input angular velocity, which is the angular velocity of the input shaft 22. This ratio is obtained by dividing the output angular velocity by the input angular velocity. The continuously variable transmission 2 of this embodiment is an infinite speed ratio continuously variable transmission, and is configured so that the variable range of the actual speed ratio includes zero. An infinite speed ratio continuously variable transmission is sometimes referred to as an "Infinitely Variable Transmission," and is sometimes abbreviated as "IVT." An actual speed ratio of zero refers to a case where the actual speed ratio is 1 / ∞. Here, an example of such a continuously variable transmission 2 will be described, but the specific example is not particularly limited.

[0032] The input shaft 22 includes an input member 221 to which rotation is input from the motor 11, a shaft 222 connected to the input member 221, and a sleeve 223 fixed to the shaft 222. The specific structure of the input shaft 22 is not particularly limited as long as it can transmit rotation from the motor 11 to the transmission mechanism 24. Here, an example is shown in which the input shaft 22 is configured with multiple members, but it may also be configured with a single member, and the number of members is not particularly limited.

[0033] The transmission mechanism 24 includes an input bearing ring 40 rotatably mounted on the input shaft 22, a first support bearing ring 42 rotatably supported on the input shaft 22, a second support bearing ring 46 axially movably mounted within a casing 44 of the continuously variable transmission 2, an output bearing ring 48 rotatably mounted on the output shaft 25, and a plurality of rolling elements 41. The bearing rings 40, 42, 46, and 48 are collectively referred to simply as bearing rings. The plurality of rolling elements 41 roll on each of the bearing rings 40, 42, 46, and 48. The plurality of rolling elements 41 are pressed against the output bearing ring 48 by a pressing force applied from the second support bearing ring 46 by a pressing force applying mechanism (not shown).

[0034] When the input bearing ring 40 rotates, the rolling elements 41 rotate about the rotation axis LB while revolving around the rotation axis LA, which is the orbital axis of the input shaft 22. As the rolling elements 41 revolve, the output bearing ring 48 rotates about the rotation axis LA in response. Ideally, the output bearing ring 48 rotates at an output angular velocity obtained by multiplying the input angular velocity of the input shaft 22 by the gear ratio. This gear ratio is determined according to the inclination angle of the rotation axis LB with respect to the rotation axis LA, and is changed by the gear ratio change mechanism 23.

[0035] The output shaft 25 includes an output raceway 48 and an output member 251 that is connected to the output raceway 48 so as to rotate integrally with the output raceway 48 and outputs rotation to the driven device 27. The specific structure of the output shaft 25 is not particularly limited as long as it can transmit rotation from the speed change mechanism 24 to the driven device 27. While the output shaft 25 shown here is an example formed of multiple members, it may also be formed of a single member, and the number of members is not particularly limited.

[0036] The gear ratio change mechanism 23 of this embodiment is capable of changing the gear ratio by changing the attitude of the input race 40. The gear ratio change mechanism 23 includes a shaft-shaped gear ratio input portion 26 that is movable in the axial direction by power output from the gear ratio change device 31, and a ring member 232 that is movable in the axial direction integrally with the gear ratio input portion 26. The ring member 232 rotatably supports the input shaft 22 via a bearing 233, and is movable in the axial direction integrally with the input shaft 22 by a snap ring or the like. There are no particular limitations on the specific example of the gear ratio change mechanism 23, and various mechanisms similar to those employed in the continuously variable transmission 2 may be employed.

[0037] When axial power is input from the gear ratio change device 31 to the gear ratio input section 26, the input shaft 22, including the input race 40 and the first support race 42, moves axially together with the ring member 232. The axial movement of the input race 40 and the first support race 42 relative to the second support race 46 and the output race 48 changes the inclination angle of the rotation axis LB of the rolling elements 41 relative to the rotation axis LA, changing the gear ratio according to that inclination angle. This gear ratio is zero when the rotation axis LB is parallel to the rotation axis LA and increases continuously as the inclination angle of the rotation axis LB relative to the rotation axis LA increases. In other words, the actual gear ratio can be changed continuously or steplessly, and the variable range includes zero.

[0038] The present applicant has disclosed examples of infinitely variable speed ratio continuously variable transmissions in Japanese Patent Application Laid-Open No. 2021-181812, Japanese Patent Application Laid-Open No. 2022-135086, etc., and the technology of continuously variable transmissions will be understood by those skilled in the art.

[0039] Next, referring to FIG. 3 , the relationship between the output shaft torque T1 of the continuously variable transmission 2 and the relative slip R1 of the angular velocity between the input shaft 22 and the output shaft 25 will be described. Hereinafter, the output shaft torque T1 may be referred to as "torque T1," and the relative slip R1 of the angular velocity may be referred to as "slip R1." FIG. 3 is a diagram showing an example of the relationship between the slip R1 and the torque T1 of the continuously variable transmission 2. In this diagram, the horizontal axis represents the slip R1, and the vertical axis represents the torque T1. The diagram shows a case where the angular velocity of the output shaft 25 is 2 (rad / s). In this diagram, the zero and positive regions of the torque T1 indicate a power running state, and the negative region indicates a regenerative state. q1, q2, q3, q4, q5, q6, and q7 indicate the relationship between the slip R1 and the torque T1 corresponding to the gear ratio.

[0040] Because the continuously variable transmission 2 is a traction mechanism having rolling elements 41 and bearing rings that contact each other, slip R1 occurs between the input shaft 22 and the output shaft 25 in response to torque T1. Slip R1 can be defined by Equation 1: Slip R1 = [1 - output shaft angular velocity / (gear ratio x input shaft angular velocity)] (Equation 1). In FIG. 3, slip R1 is expressed as a percentage. As shown in FIG. 3, when slip R1 is zero, torque T1 is approximately zero, and torque T1 increases approximately nonlinearly as slip R1 increases. Note that these relationships can be interpreted as a relationship in which slip R1 increases as torque T1 increases, or as a relationship in which torque T1 increases as slip R1 increases.

[0041] 3, the relationship between slip R1 and torque T1 varies significantly depending on the gear ratio. As such, the relationship between slip R1 and torque T1 is nonlinear and varies depending on the gear ratio. Therefore, if the output of the continuously variable transmission 2 is controlled based on a target without taking the relationship between slip R1 and torque T1 into consideration, it is difficult to improve the control accuracy. The outputs of the continuously variable transmission 2 are the torque of the output shaft 25, the angular velocity of the output shaft 25, and the angular position of the output shaft 25.

[0042] In light of the above, in the present embodiment, as an example, the command signal supply unit 50 generates the rotation command signal S1 and the gear ratio command signal P1 using relationship data D1 between the torque T1 and slip R1 of the continuously variable transmission 2. For this purpose, the continuously variable transmission system 100 includes a relationship data storage unit 52 that stores the relationship data D1. In the present embodiment, the relationship data storage unit 52 is provided within the command signal supply unit 50, but may be provided outside the command signal supply unit 50. The relationship data D1 can be obtained in advance by actually measuring or simulating the relationship between the torque T1 and slip R1 for the continuously variable transmission 2.

[0043] The gear ratio command signal P1 and the rotation command signal S1 can also be generated simultaneously. As an example, the command signal supply unit 50 of this embodiment generates either the gear ratio command signal P1 or the rotation command signal S1 using the relationship data D1, and generates the other command signal from the generated one command signal. In this case, the generation algorithm is simplified and the device can be configured as a small-scale device. In this embodiment, the gear ratio command signal P1 is generated using the relationship data D1, and the rotation command signal S1 is generated from the generated gear ratio command signal P1.

[0044] The continuously variable transmission system 100 is in a powering state in which the continuously variable transmission 2 provides positive kinetic energy to the driven device 27, and a regenerative state in which the continuously variable transmission 2 provides negative kinetic energy to the driven device 27. Note that the powering state also includes a state in which neither positive nor negative kinetic energy is provided. In this embodiment, the command signal supply unit 50 switches the generation algorithm between a powering mode corresponding to the powering state and a regenerative mode corresponding to the regenerative state.

[0045] Specifically, the command signal supply unit 50 has a powering mode and a regenerative mode as generation modes for generating the gear ratio command signal P1 and the rotation command signal S1, and generates the gear ratio command signal P1 and the rotation command signal S1 in either the powering mode or the regenerative mode based on the mode determination result of the mode determination unit 54. In this case, control accuracy can be improved by using a generation algorithm suitable for each mode. The generation algorithm may be, for example, a transfer function.

[0046] The polarity of the slip R1 value changes between the powering state and the regenerative state. For example, the slip R1 value has a positive polarity in the powering state and a negative polarity in the regenerative state. Therefore, the mode can be determined according to the polarity of the slip R1 value calculated from the angular velocity of the input shaft 22, the angular velocity of the output shaft 25, and the gear ratio input by the gear ratio input unit 26.

[0047] In this embodiment, the mode discrimination unit 54 discriminates between the powering mode and the regenerative mode based on the detection result F1 that is the detection result of the output shaft information detection unit 16 and the input side information F2 that is the detection result of the input shaft information detection unit 14. In particular, the mode discrimination unit 54 determines whether or not the regenerative state is in effect based on the relationship between the angular velocity of the input shaft 22 and the angular velocity of the output shaft 25, and if the regenerative state is in effect, the mode discrimination unit 54 discriminates as the regenerative mode, and if the regenerative state is not in effect, the mode discrimination unit 54 discriminates as the powering mode.

[0048] A method for generating the gear ratio command signal P1 in the command signal supply unit 50 will be described. The command signal supply unit 50 generates the gear ratio command signal P1 through calculation using a torque generation model 55 of the motor 11 and the continuously variable transmission 2. The torque generation model 55 is a model that receives three parameters, namely the gear ratio, the angular velocity of the input shaft 22, and the angular velocity of the output shaft 25, as input, and outputs the torque of the output shaft 25, and incorporates relationship data D1. The torque generation model 55 can be obtained in advance by actually measuring or simulating the relationships between the torque T1, the gear ratio, the angular velocity of the input shaft 22, and the angular velocity of the output shaft 25 for the motor 11 and the continuously variable transmission 2. The command signal supply unit 50 has two torque generation models 55, one for the powering mode and one for the regenerative mode, and switches between them based on the mode determination result.

[0049] The angular velocity of the input shaft 22 can be calculated from the input side information F2, and the angular velocity of the output shaft 25 can be calculated from the detection result F1.

[0050] The method for generating the rotation command signal S1 in the command signal supply unit 50 will now be described. The rotation command signal S1 can be generated by substituting the generated gear ratio command signal P1 and the angular velocity of the input shaft 22 into a calculation model. This calculation model can be obtained in advance by actually measuring or simulating the relationship between the gear ratio command signal P1 and the angular velocity of the input shaft 22.

[0051] Studies have shown that the relationship between the gear ratio and the angular velocity of the input shaft 22 has a number of different characteristics. FIG. 4 is a diagram schematically illustrating an example of the relationship between the gear ratio and the angular velocity of the input shaft 22. In this diagram, the horizontal axis represents the gear ratio, and the vertical axis represents the angular velocity. As shown in FIG. 4, the relationship between the gear ratio and the angular velocity of the input shaft 22 can have a variety of characteristics, such as a linear characteristic shown in g1, a convex curve characteristic shown in g2, and a concave curve characteristic shown in g3. Therefore, the relationship between the gear ratio and the angular velocity of the input shaft 22 can be specified in advance and incorporated into a calculation model that generates the rotation command signal S1. The relationship between the gear ratio and the angular velocity of the input shaft 22 can be considered as correction information for correcting the transfer function of the command signal supply unit 50.

[0052] Another method for generating the gear ratio command signal P1 and the rotation command signal S1 is to use a learning model. This learning model can be generated in advance by machine learning based on a data set of actual measurements of the torque of the output shaft 25, the gear ratio, the angular velocity of the input shaft 22, and the angular velocity of the output shaft 25 collected for the motor 11 and the continuously variable transmission 2. The learning model can be generated using known machine learning techniques, such as a support vector machine, a neural network including deep learning, or a random forest, and is stored in a memory unit (not shown) within the command signal supply unit 50. Using the learning model makes it possible to flexibly configure a control system that can achieve high-precision control.

[0053] The continuously variable transmission system 100 of this embodiment configured as described above uses the torque command signal C1 as a target value and controls the motor 11 and the gear ratio change device 31 so that the torque of the output shaft 25 of the continuously variable transmission 2 approaches the target value, and drives the driven device 27 by the rotation of the output shaft 25.

[0054] The following describes the features of the continuously variable transmission system 100 configured as described above. The continuously variable transmission system 100 includes a continuously variable transmission 2 having rolling elements 41 and raceways in contact with the rolling elements 41, which changes the speed of rotation of an input shaft 22 and outputs the rotation to an output shaft 25, a motor 11 which inputs the rotation to the input shaft 22, an input shaft control unit 10 which controls the angular velocity of the input shaft 22 via the motor 11, a gear ratio change device 31 which changes the gear ratio of the continuously variable transmission 2, a gear ratio control unit 30 which controls the gear ratio via the gear ratio change device 31, an output shaft information detection unit 16 which detects rotation information of the output shaft 25, and a command signal supply unit 50 which supplies a gear ratio command signal P1 to the gear ratio control unit 30 and a rotation command signal S1 to the input shaft control unit 10 based on a torque command signal C1 related to the torque of the output shaft 25 and a detection result F1 which is the detection result of the output shaft information detection unit 16.

[0055] According to this configuration, the torque of the output shaft 25 of the continuously variable transmission 2 can be controlled based on the torque command signal C1 related to the torque of the output shaft 25, making it possible to control the torque of the output shaft 25 of the continuously variable transmission 2 with high precision.

[0056] The above is the description of the first embodiment.

[0057] Second Embodiment A continuously variable transmission system 100 according to a second embodiment of the present disclosure will be described with reference to Fig. 5 . Fig. 5 is a block diagram of the continuously variable transmission system 100 of this embodiment. The continuously variable transmission system 100 of this embodiment differs from the first embodiment in that it includes an angular velocity control unit 60 that provides a torque command signal C1 to a command signal supply unit 50 based on the angular velocity of the output shaft 25 detected by the output shaft information detection unit 16 and an angular velocity command signal J1 related to the angular velocity of the output shaft 25. The remaining configuration is the same. Therefore, the following description will focus on the differences.

[0058] The continuously variable transmission system 100 of this embodiment controls the output rotation of the continuously variable transmission 2 that drives the driven device 27 based on an angular velocity command signal J1 provided from outside the system. The angular velocity control unit 60 calculates the angular velocity of the output shaft 25 from the detection result F1 of the output shaft 25 detected by the output shaft information detection unit 16, compares the calculation result with the angular velocity command signal J1, and generates and outputs a torque command signal C1 for the output shaft 25 based on the comparison result.

[0059] For example, the angular velocity command signal J1 is provided from a higher-level means. This higher-level means is not limited as long as it is an element that can generate the angular velocity command signal J1, and may be, for example, a higher-level control element. The higher-level means may be provided within the continuously variable transmission system 100. The angular velocity command signal J1 may be a target value for the angular velocity of the output shaft 25, and the detection result F1 may be a feedback value.

[0060] The continuously variable transmission system 100 of this embodiment configured as described above uses the angular velocity command signal J1 as a target value, controls the motor 11 and the gear ratio change device 31 so that the angular velocity of the output shaft 25 of the continuously variable transmission 2 approaches the target value, and drives the driven device 27 through the rotation of the output shaft 25. This makes it possible to control the angular velocity of the output shaft 25 of the continuously variable transmission 2 with high precision.

[0061] The continuously variable transmission system 100 of this embodiment has the same functions and effects as the first embodiment to the extent that they are not inconsistent. This concludes the description of the second embodiment.

[0062] Third Embodiment A continuously variable transmission system 100 according to a third embodiment of the present disclosure will be described with reference to Fig. 6 . Fig. 6 is a block diagram of the continuously variable transmission system 100 of this embodiment. The continuously variable transmission system 100 of this embodiment differs from the first embodiment in that it includes an angular position control unit 62 that provides a torque command signal C1 to a command signal supply unit 50 based on an angular position command signal K1 related to the angle of the output shaft 25 detected by the output shaft information detection unit 16 and the angular position of the output shaft 25. The remaining configuration is the same. Therefore, the following description will focus on the differences.

[0063] The continuously variable transmission system 100 of this embodiment controls the output rotation of the continuously variable transmission 2 that drives the driven device 27 based on an angular position command signal K1 provided from outside the system.

[0064] The continuously variable transmission system 100 of this embodiment controls the output rotation of the continuously variable transmission 2 that drives the driven device 27 based on an angular position command signal K1 provided from outside the system. The angular position control unit 62 calculates the output shaft 25 from the detection result F1 of the output shaft 25 detected by the output shaft information detection unit 16, compares the calculation result with the angular position command signal K1, and generates and outputs a torque command signal C1 for the output shaft 25 based on the comparison result.

[0065] For example, the angular position command signal K1 is provided from a higher-level means. This higher-level means is not limited as long as it is an element capable of generating the angular position command signal K1, and may be, for example, a higher-level control element. The higher-level means may be provided within the continuously variable transmission system 100 or may be provided outside the system. The angular position command signal K1 may be a target value for the angular position of the output shaft 25, and the detection result F1 may be a feedback value.

[0066] The continuously variable transmission system 100 of this embodiment configured as described above uses the angular position command signal K1 as a target value, controls the motor 11 and the gear ratio change device 31 so that the angular position of the output shaft 25 of the continuously variable transmission 2 approaches the target value, and drives the driven device 27 through the rotation of the output shaft 25. This makes it possible to control the angular position of the output shaft 25 of the continuously variable transmission 2 with high precision.

[0067] The continuously variable transmission system 100 of this embodiment has the same functions and effects as the first embodiment to the extent that they are not inconsistent. This concludes the description of the third embodiment.

[0068] The above description is based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications and variations are possible and that such modifications and variations are within the scope of the claims of the present disclosure. Therefore, the descriptions and drawings in this specification should be treated as illustrative rather than restrictive.

[0069] (Modifications) Modifications will be described below. In the drawings and descriptions of the modifications, the same components and members as those in the embodiment will be denoted by the same reference numerals. Explanations that overlap with the embodiment will be omitted as appropriate, and the description will focus on the configurations that differ from the embodiment.

[0070] In the above description, an example has been shown in which the angular velocity of the input shaft 22 is directly controlled, but the angular velocity of the input shaft 22 may be indirectly controlled by controlling the input shaft torque or input shaft angle.

[0071] In the above description, an example has been shown in which the mode is determined based on the value of slip R1 calculated from the angular velocity of the input shaft 22, the angular velocity of the output shaft 25, and the gear ratio by the gear ratio input unit 26, but the present disclosure is not limited to this. For example, the powering mode and the regenerative mode may be determined based on the product of the angular velocity of the output shaft and the torque command signal C1. If the product of the angular velocity of the output shaft and the torque command signal C1 is zero or positive, the powering mode is determined, and if it is negative, the regenerative mode is determined.

[0072] Alternatively, the powering mode and the regenerative mode may be determined by a calculation model including the angular velocity of the input shaft, the angular velocity of the output shaft, and the torque command signal C1 as parameters. This calculation model can be obtained in advance by measuring or simulating the characteristics of the continuously variable transmission.

[0073] In the above description, an example has been shown in which the motor shaft and the input shaft of the continuously variable transmission are directly connected, but the present disclosure is not limited to this. For example, the motor shaft and the input shaft of the continuously variable transmission may be connected via various known transmission mechanisms such as gears, chains, or belts.

[0074] In the above description, an example was given in which the gear ratio input detector 35 is a rotary encoder, but the present disclosure is not limited to this. For example, the gear ratio input detector 35 may be a linear encoder.

[0075] In the above description, an example has been shown in which each control unit of the continuously variable transmission system 100 performs feedback control, but the present disclosure is not limited to this. For example, any of the control units of the continuously variable transmission system 100 may perform feedforward control. Furthermore, the continuously variable transmission system 100 may include a state estimation unit using an observer.

[0076] In the above description, an example has been shown in which the mode discriminator 54 is provided within the command signal supply unit 50, but the mode discriminator may also be provided outside the command signal supply unit.

[0077] Each of these modifications provides the same functions and effects as the embodiment.

[0078] Any combination of the above-described embodiments and modifications is also useful as an embodiment of the present disclosure. A new embodiment resulting from the combination has the combined effects of the combined embodiments and modifications.

[0079] The present disclosure relates to a continuously variable transmission system, a continuously variable transmission, and a method for controlling a continuously variable transmission system.

[0080] 2 Continuously variable transmission, 10 Input shaft control unit, 11 Motor, 12 Motor drive unit, 13 Motor control unit, 14 Input shaft information detection unit, 16 Output shaft information detection unit, 22 Input shaft, 23 Gear ratio change mechanism, 25 Output shaft, 26 Gear ratio input unit, 30 Gear ratio control unit, 31 Gear ratio change device, 40 Input bearing ring, 41 Rolling element, 42 First support bearing ring, 46 Second support bearing ring, 48 Output bearing ring, 50 Command signal supply unit, 52 Relationship data storage unit, 54 Mode discrimination unit, 55 Torque generation model, 60 Angular velocity control unit, 62 Angular position control unit, 100 Continuously variable transmission system.

Claims

1. A continuously variable transmission having rolling elements and raceways in contact with the rolling elements, which changes the rotation of an input shaft and outputs it to an output shaft, a drive source for inputting rotation to the input shaft, an input shaft control unit for controlling the rotation of the input shaft through the drive source, a transmission ratio changing device for changing the transmission ratio of the continuously variable transmission, a transmission ratio control unit for controlling the transmission ratio through the transmission ratio changing device, an output shaft information detection unit for detecting rotation information of the output shaft, and a command signal supply unit for supplying a transmission ratio command signal to the transmission ratio control unit and a rotation command signal to the input shaft control unit based on an output command signal regarding the output shaft and a detection result of the output shaft information detection unit. A continuously variable transmission system comprising:

2. The continuously variable transmission system according to claim 1, wherein the input shaft control unit is an angular velocity control unit that controls the angular velocity of the input shaft.

3. The continuously variable transmission system according to claim 1 or 2, wherein the command signal supply unit generates the rotation command signal and the transmission ratio command signal to the input shaft control unit using relationship data between the output shaft torque of the continuously variable transmission and the relative slip of the angular velocities of the input shaft and the output shaft.

4. The continuously variable transmission system according to claim 3, wherein the command signal supply unit generates one of the transmission ratio command signal and the rotation command signal using the relationship data, and generates the other command signal from the generated one command signal.

5. The continuously variable transmission system according to any one of claims 1 to 4, wherein the command signal supply unit has a power running mode and a regeneration mode as generation modes for generating the transmission ratio command signal and the rotation command signal, and generates the transmission ratio command signal and the rotation command signal by either the power running mode or the regeneration mode based on a mode discrimination result.

6. The continuously variable transmission system according to claim 5, further comprising an input shaft information detection unit for detecting the rotation of the input shaft, wherein the command signal supply unit has a mode discrimination unit for discriminating between the power running mode and the regeneration mode based on the detection result of the output shaft information detection unit and the detection result of the input shaft information detection unit.

7. The continuously variable transmission system according to any one of claims 1 to 6, further comprising an angular velocity control unit for giving the output command signal to the command signal supply unit based on an angular velocity command signal regarding the angular velocity of the output shaft and the angular velocity of the output shaft detected by the output shaft information detection unit.

8. The continuously variable transmission system according to any one of claims 1 to 6, further comprising an angular position control unit that supplies the output command signal to the command signal supply unit based on an angular position command signal related to the angular position of the output shaft and the angular position of the output shaft detected by the output shaft information detection unit.

9. The continuously variable transmission system according to any one of claims 1 to 8, wherein the output command signal related to the output shaft is a torque command signal related to the torque of the output shaft.

10. A continuously variable transmission having rolling elements and raceway rings that contact the rolling elements, which changes the rotation of an input shaft and outputs it to an output shaft, wherein the transmission ratio of the continuously variable transmission and the rotation of the input shaft are controlled based on an output command signal related to the rotation of the output shaft and the rotation information of the output shaft.

11. Regarding a control method for a continuously variable transmission system including a continuously variable transmission having rolling elements and raceway rings that contact the rolling elements, which changes the rotation of an input shaft and outputs it to an output shaft, and a transmission ratio changing device that changes the transmission ratio of the continuously variable transmission, the method includes: detecting the rotation information of the output shaft; and controlling the transmission ratio of the continuously variable transmission and the rotation of the input shaft based on an output command signal related to the rotation of the output shaft and the rotation information.

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