Electrically actuated CVT pulley

Abstract

A product may include a rotating pulley that may have a first pulley half and a second pulley half. The distance between the first pulley half and the second pulley half may be variable. The screw actuator may have a screw that may engage the first pulley half. A motor may be connected with the screw and may be operable to move the first pulley half through the screw to vary the distance.

Description

[0001] This application is a divisional application of a Chinese patent application with an application date of March 1, 2017, an application number of 201710117000.3, and an invention title of "Electrically Actuated CVT Pulley".

[0002] Cross - reference to related applications

[0003] This application claims the benefit of U.S. Provisional Application No. 62 / 306,852, filed on March 11, 2016. Technical field

[0004] The present invention generally relates to the field of electrically actuated devices, and more particularly to electrically actuated pulleys in continuously variable transmissions (CVTs). Background art

[0005] A CVT can be used to continuously change the gear ratio between an input shaft and an output shaft. The driveline of a vehicle can include a CVT located between an engine and drive wheels to provide a range of relative speeds between the input shaft and the output shaft. Summary of the invention

[0006] A number of illustrative variations can relate to a product that can include a rotating pulley having a first pulley half and a second pulley half. The distance between the first pulley half and the second pulley half can be variable. A screw actuator can have a screw that engages the first pulley half. A motor can be connected to the screw and be operable to move the first pulley half via the screw to change the distance.

[0007] From the detailed description provided herein, other illustrative variations within the scope of the present invention will become apparent. It should be understood that although variations within the scope of the present invention are disclosed, the detailed description and specific examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Brief description of the drawings

[0008] Selected examples of variations within the scope of the present invention will be more thoroughly understood from the detailed description and the drawings, in which:

[0009] Figure 1 is a schematic view of a product according to several variations.

[0010] Figure 2 is a schematic view of a part of a product according to several variations.

[0011] Figure 3 is a schematic view of a part of a product according to several variations.

[0012] Figure 4 is a schematic view of a product according to several variations. Detailed Implementation Modes

[0013] The following description of the variations is merely illustrative in nature and is in no way intended to limit the scope of the present invention, its applications, or its use.

[0014] In several variations as Figure 1 shown, the product 10 may include an input operation 12 and an output operation 14. The input operation 12 may take the form of a rotating driven shaft 16. The shaft 16 may be connected to a power device 18, which may be an engine, such as an internal combustion engine, or may be an alternative power device, or a hybrid arrangement. The output operation 14 may take the form of a rotating drive shaft 20. Through a gear mechanism 24, the shaft 20 may be connected to one or more wheels 22 and may drive the one or more wheels. The gear mechanism 24 may include a differential unit to split torque and may include additional gears to transfer motion to the wheels 22. The wheels 22 may require a range of speed inputs from the shaft 20 and may operate under various conditions with varying torque requirements. Accordingly, the power device 18 may operate within a range of rotational speeds, and the product 10 may provide various gear ratios between the shaft 16 and the shaft 20.

[0015] In several variations, the shaft 16 may be connected to a torque transmission element 26 through a coupling 28. The torque transmission element 26 may supply a drive input to a downstream load, which may include the wheels 22. When the power device 18 includes an internal combustion engine, the coupling 28 may be a torque converter type fluid coupling. The shaft 16 may be connected to an impeller 30. The torque transmission element 26 may be connected to a turbine 32 through a housing portion 34. A stator 36 may be positioned between the impeller 30 and the turbine 32 and may affect the power transmission from the shaft 16 to the torque transmission element 26 through the coupling 28. The stator 36 may be grounded at the outer housing 38. The rotation of the impeller 30 may act through the fluid in the coupling 28 to rotate the turbine 32, such that the torque transmission element 26 is driven by the shaft 16. The coupling 32 may allow the impeller 30 to rotate relative to the turbine 32, and the stator 36 may produce a torque multiplication between the impeller 30 and the turbine 32. A lock-up clutch 40 may be provided to lock the impeller 30 and the turbine 32 together through the housing 34 such that they rotate together.

[0016] In several variants, the torque transmission element 26 can be connected to the shaft 42 by a reverse drive unit 44, which can generate several operating modes. The operating modes can include idling, forward and reverse operations. The torque transmission element 26 can be connected to the carrier 46 or formed as part of the carrier. The carrier 46 can carry a number of planetary gears 48 in a spaced-apart state. The planetary gears 48 can mesh with the external teeth on the sun gear 50 and can mesh with the internal teeth on the ring gear 52. The forward clutch 54 can be connected between the carrier 46 and the sun gear 50. The forward clutch 54 can be a friction plate type wet clutch, which can include a number of fixed inner plates to rotate together with one of the carrier 46 or the sun gear 54, and a number of fixed sandwich outer plates to rotate together with the other of the carrier 46 or the sun gear 54. An actuator (not shown) can selectively generate compression of the inner and outer plates so that they rotate together, and can drive the sun gear 54 from the carrier 46 to provide a forward drive mode, and the ring gear 52 rotates freely. The reverse clutch 55 can be a friction plate type wet clutch, which can include a number of plates fixed to rotate together with the ring gear 52; and a number of sandwich plates fixed to the housing 56. An actuator (not shown) can selectively generate compression of the plates so that the ring gear 52 is grounded to the housing 56 so that the sun gear 50 rotates in reverse when driven by the carrier 46 through the planetary gears 48, thereby providing a reverse drive mode. In the forward drive mode, the reverse clutch 55 can be opened or disengaged, and in the reverse drive mode, the forward clutch 54 can be opened or disengaged. The clutches 54, 55 can both be opened to provide an idling mode.

[0017] In several variants, at the drive pulley 60, the shaft 42 can be connected to the transmission unit 58. The power unit 18 can drive the pulley 60 through the shaft 42. The drive pulley 60 is connected to the driven pulley 62 by a connecting member 64, which can be a belt or a chain that can surround the pulleys 60, 62. The drive pulley 60 and the driven pulley 62 can each employ pulleys with adjustable operating diameters for use with the connecting member 64. The left halves 61, 63 of the pulleys 60, 62 (as shown in Figure 1 ), and the right halves 67, 68 (as shown in Figure 1As shown in [reference], they can be moved closer together or further apart to change the operating diameters of pulleys 60 and 62. Changing the distance between the two halves 61 and 67 on the one hand and the distance between the two halves 63 and 68 on the other hand causes the connecting member 64 to slide higher or lower within the grooves of their respective pulleys 60 and 62. This can change the effective drive ratio between the drive pulley 60 and the driven pulley 62. One or more actuator units 70 and / or 72 can be provided in the speed change unit 58 to produce the relative movement of the pulley halves 61 and 67 with respect to each other, and / or to produce the relative movement of the pulley halves 63 and 68 with respect to each other. The actuator units 70 and / or 72 can be of the planetary roller screw type actuator. An electronic controller (not shown) can control the operation of the actuator units 70 and / or 72 in a pre-programmed manner in response to the operating conditions.

[0018] In several variants, the actuator unit 70 generally can include a motor 74, a gear reduction unit 76, and a screw actuator unit 78. The motor 74 can provide a relatively high power-to-volume ratio, and thus, can be a brushless DC motor or another type. The motor 74 can drive a shaft 80 that can be connected to a brake 82. The brake 82 can be an electromagnetic friction brake, and when power is not supplied to the brake 82, it can normally be closed to keep the shaft 80 from rotating. By generally holding the shaft 80, the brake 82 can fix the pulley half 61 in place relative to the pulley half 67. This can reduce the duty cycle of the motor 74 and can maximize the efficiency of the product 10 by minimizing the power consumption during non-transient vehicle maneuvers. The screw actuator unit 78 can be of the planetary roller screw type unit, which can include a nut 84, a screw 86, and several planetary rollers 88 positioned between the nut 84 and the screw 86. The planetary rollers 88 can include threads that mesh with the threads located on each of the nut 84 and the screw 86. The rotation of the nut 84 can cause the planetary rollers 88 to rotate, which in turn can cause the screw 86 to translate linearly. The screw 86 can be hollow, and the shaft 42 can extend completely through its hollow center. The screw 86 can be engaged with the pulley half 61 so as to optionally drive it forward and move it away from the pulley half 67. The nut 84 can include an external gear 90, which can be engaged with the gear reduction unit 76 and driven by the gear reduction unit 76.

[0019] In several variations, the gear reduction unit 76 can produce a reduced rotational speed and an increased torque between the shaft 80 and the nut 86. The shaft 80 can provide an input into the two-stage reduction planetary arrangement at a first stage of the two-stage reduction planetary arrangement through the sun gear 92. The sun gear 92 can mesh with a plurality of planetary gears 94 carried by a carrier 96. The planetary gears 94 can mesh with an annular gear 98 that can be fixed to the housing 100. The annular gear can extend over the first and second stages of the planetary arrangement. The carrier 96 can be fixedly connected to a sun gear 102, providing an input to the second stage. The sun gear 102 can mesh with a plurality of planetary gears 104 carried by a carrier 106. The planetary gears 104 can mesh with the annular gear 98. The carrier 106 can be fixedly connected to a torque transmission element 108, which can provide an output from the two-stage reduction planetary arrangement. The input from the shaft 80 can be transmitted to the torque transmission element 108 successively through the sun gear 92, the planetary gears 94, the carrier 96, the sun gear 102, the planetary gears 104, and the carrier 106. When the annular gear 98 is fixed, the rotational speed can be reduced through two stages, and the torque can be multiplied through the two stages of the two-stage reduction planetary arrangement.

[0020] In several variations, the torque transmission element 108 can be a fixed connection or an integral structure between the carrier 108 and a gear 110. The gear 110 can mesh with a gear 112 and can drive the gear 112. The gear 112 can have a larger diameter and a greater number of teeth compared to the gear 110 to provide a speed reduction. The gear 112 can be connected to or integrally formed with a gear 114. The gear 114 can mesh with an external gear 90 on the nut 84 and can drive the external gear 90. The external gear 90 can have a larger diameter and a greater number of teeth compared to the gear 114 to provide a speed reduction. The motor 74 can be reversible and can produce a linear translation of the pulley half 61 through the gear reduction unit 76, the screw actuator unit 78, and several intermediate gears.

[0021] In several variations, the pulley half 63 can be similarly driven by the actuator unit 72. The pulley 61 can be changed by the interconnecting motor 120 in the actuator unit 72. In several variations, the actuator unit 72 generally can include a motor 120, a gear reduction unit 122, and a screw actuator unit 124. The motor 120 can provide a relatively high power-to-volume ratio and, thus, can be a brushless DC motor. The motor 120 can drive a shaft 126 that can be connected to a brake unit 128. The brake unit 128 can be an electromagnetic friction brake and can normally be closed to keep the shaft 126 from rotating when power is not supplied to the brake unit 128. The screw actuator unit 124 can be a planetary roller screw type unit that can include a nut 130, a screw 132, and a number of planetary rollers 134 positioned between the nut 130 and the screw 132. The planetary rollers 134 can include threads that engage threads on each of the nut 130 and the screw 132. Rotation of the nut 130 can cause the planetary rollers 134 to rotate, which in turn can cause the screw 132 to translate linearly. The screw 132 can be hollow, and the shaft 20 can extend completely through its hollow center. The screw 132 can engage the pulley half 63 to optionally drive it forward and away from the pulley half 68. The nut 130 can include an external gear 136 that can engage and be driven by the gear reduction unit 122.

[0022] In several variations, the gear reduction unit 122 can produce a reduced rotational speed and an increased torque between the shaft 126 and the nut 130. The shaft 126 can provide an input to a two-stage reduction planetary arrangement at a first stage of the two-stage reduction planetary arrangement through a sun gear 138. The sun gear 138 can engage a number of planetary gears 142 carried by a carrier 140. The planetary gears 142 can engage an annular gear 144 that can be fixed to the housing 100. The annular gear 144 can extend over the first and second stages of the planetary arrangement. The carrier 140 can be fixedly connected to a sun gear 146, providing an input to the second stage. The sun gear 146 can engage a number of planetary gears 148 carried by a carrier 150. The planetary gears 148 can engage the annular gear 144. The carrier 150 can be fixedly connected to a torque transmission element 152 that can provide an output from the two-stage reduction planetary arrangement. The input from the shaft 126 can be transmitted to the torque transmission element 152 sequentially through the sun gear 138, the planetary gears 142, the carrier 140, the sun gear 146, the planetary gears 148, and the carrier 150. With the annular gear 144 fixed, the speed can be reduced by two stages, and the torque can be multiplied by two stages of the two-stage reduction planetary arrangement.

[0023] In several variations, the torque transmission element 152 can be a fixed connection between the carrier 150 and the gear 154, or can be an integral structure between the carrier 150 and the gear 154. The gear 154 can mesh with the gear 156 and can drive the gear 156. The gear 156 can have a larger diameter and a greater number of teeth than the gear 154 to provide a speed reduction. The gear 156 can be connected to the gear 158 or can be integrally formed with the gear 158. The gear 158 can mesh with the external gear 136 on the nut 130 and can drive the external gear 136. The external gear 136 can have a larger diameter and a greater number of teeth than the gear 158 to provide a speed reduction. The motor 120 can be reversible and can generate linear translation of the pulley half 63 through the gear reduction unit 122, the screw actuator unit 124, and several intermediate gears.

[0024] Reference Figure 2 , shows a screw actuator unit 124 according to several variations. The motor 120 can include a stator 160 and a rotor 162, and the rotor can be connected to the shaft 126. The shaft 126 can extend out of both ends of the rotor 162. The brake unit 128 can be connected to one end 164 of the shaft 126 using a disk 165, and the disk is fixed to rotate with the shaft 126. A pressure plate 168 can be disposed adjacent to the disk 165, and a friction material 170 is disposed between the pressure plate 168 and the disk 165. A back plate 172 can be positioned on one side of the disk 165, opposite to the pressure plate 168. A friction material 174 can be disposed between the back plate 172 and the disk 165. A spring plate 178 can be positioned against the pressure plate 168, and the disk 165 between the pressure plate 168 and the back plate 172 can be normally compressed through the friction materials 170, 174 to keep the shaft 126 from rotating. A coil 176 can be positioned adjacent to the pressure plate 168 and can be energized to compress the spring plate 178 by pulling the pressure plate 168, thereby releasing the disk 174 to allow the shaft 126 to rotate.

[0025] The screw actuator unit 124 may include a nut 130, a screw 132, and planetary rollers 134. The pulley half 63 may be supported on the shaft 20, and the pulley half 63 may translate along the length of the shaft 20. The pulley half 63 and the shaft 20 may include a key and groove connection to allow translation but prohibit relative rotation. The screw 132 may be hollow, and the shaft 20 may extend completely through its hollow center. The screw 132 may be operable bidirectionally on the pulley half 63 through a thrust washer 180, and against the housing 100 through a thrust washer 182. For purposes of illustration, the pulley half 63 is shown in a first position at the top of the shaft 20 and a second position at the bottom of the shaft 20, and the screw 132 extends to the right. It will be understood that the pulley half 63 may be of annular shape, and its upper and lower portions will move together in an aligned relationship. The nut 130 and the planetary rollers 134 may be carried on the housing 100 such that they may rotate but do not translate with the screw 132. When the pulley half 63 is sequentially driven through the sun gear 138, planetary gears 142, carrier 140, sun gear 146, planetary gears 148, carrier 150, torque transfer element 152, gears 154, 156, and 158, nut 130, planetary rollers 134, and screw 132, it may translate linearly in opposite directions from the pulley half 68. Refer to Figure 3 , which shows a portion through the actuator unit 72, the screw 132 may be surrounded by the nut 130, and the planetary rollers 134 may be carried therebetween. The planetary rollers 134 may be distributed around the circumference of the screw 132 and may be evenly spaced apart, and the mating surfaces of the screw 132, planetary rollers 134, and nut 130 may all have mating gear teeth, a portion of which 190 is shown.

[0026] In several variations as Figure 4 shown, the drive pulley 60 and the driven pulley 62 may vary in accordance with the power supplied by a common motor. For example, the pulley half 63 may be driven by the motor 120 through the gear reduction unit 122, gears 154, 156, 158, and the screw actuator unit 124. The shaft 126 of the motor 120 may extend through the brake unit 128 and may be connected to the gear reduction unit 183 at its end 184. The gear reduction unit 183 may be a double planetary gear reduction unit. The output from the gear reduction unit 183 may be provided by the shaft 185. The pulley half 67 may be driven by the screw actuator unit 78. The screw actuator unit 78 may be oriented to engage the shaft 185 through gears 186, 187, and 188. Thus, the pulley half 67 may be driven by the motor 120 through the gear reduction unit 183, gears 188, 187, 186, and the screw actuator unit 78. Variations where the motor 120 drives both the drive pulley 60 and the driven pulley 62 are possible. The housing 191 may provide a structure for supporting the components in a dual drive arrangement.

[0027] With the variations described above, the pulleys of the CVT can be varied by a screw actuator. The following variation descriptions are merely illustrative descriptions of components, elements, actions, products, and methods that are considered to fall within the scope of the present invention, and are not intended in any way to limit the scope of such specifically disclosed or particularly described. The components, elements, actions, products, and methods described herein can be combined and rearranged not as specifically described herein, and still be considered to fall within the scope of the present invention.

[0028] Variation 1 can relate to a product that can include a rotating pulley that can have a first pulley half and a second pulley half, where the distance between the first pulley half and the second pulley half can be variable. The screw actuator can have a screw that can engage the first pulley half. A motor can be connected to the screw and can be operable to move the first pulley half via the screw to vary the distance.

[0029] Variation 2 can include the product according to Variation 1, where the screw actuator can include planetary rollers that can mesh with the screw. A nut can mesh with the planetary rollers. The motor can drive the nut to rotate the planetary rollers, which can linearly move the screw.

[0030] Variation 3 can include the product according to Claim 2 and can include a planetary gear set that can have a sun gear. Planetary gears can mesh with the sun gear. A ring gear can mesh with the planetary gears. The planetary gear set can be connected between the motor and the nut and can provide a gear reduction from the motor to the nut.

[0031] Variation 4 can include the product according to Variation 3, where the motor can include a rotor having a shaft that can be connected to the planetary gear set and to a brake. The brake can engage the shaft and can hold the shaft from rotating and can fix the first pulley half in place.

[0032] Variation 5 can include the product according to any one of Variations 1 - 4 and can include a wheel that can be driven by the pulley.

[0033] Variation 6 can include the product according to any one of Variations 1 - 5 and can include a power unit and a reverse drive unit that can be configured to reverse the rotation of the pulley. The power unit can drive the pulley to rotate via the reverse drive unit.

[0034] Variant 7 may include the product according to any one of variants 1-6, wherein the screw actuator may include a plurality of planetary rollers that may engage with the screw. The nut may engage with the plurality of planetary rollers and may surround the plurality of planetary rollers. The nut may have an internal gear that may engage with the plurality of planetary rollers and may have an external gear that may be driven by a motor.

[0035] Variant 8 may include the product according to any one of variants 1-7, wherein the pulley may rotate on a shaft. The screw may have a hollow center. The shaft may extend through the hollow center of the screw.

[0036] Variant 9 may relate to a product that may include a first pulley. A second pulley may be drivingly connected to the first pulley by a connecting member. At least one of the first pulley or the second pulley may have a first pulley half and an opposing second pulley half and may have a variable operating diameter produced by the movement of the first pulley half relative to the second pulley half. The screw actuator may have a screw that may engage the first pulley half. The motor may be engaged with the screw through a drive train, which may produce translation of the screw.

[0037] Variant 10 may include the product according to variant 9 and may include planetary rollers that may engage with the screw. The nut may engage with the planetary rollers. The motor may be connected to the screw through the nut and the planetary rollers.

[0038] Variant 11 may include the product according to variant 10 and may include a double reduction planetary gear set that may be connected between the motor and the nut.

[0039] Variant 12 may include the product according to variant 11, wherein the motor may include a rotor having a shaft that may be connected to the double reduction planetary gear set. A brake may engage the shaft and may hold the shaft from rotating and may fix the first pulley half in place.

[0040] Variant 13 may include the product according to any one of variants 10-12 and may include a power unit. The reverse drive unit may have a planetary gear set. The power unit may drive the first pulley through the reverse drive unit.

[0041] Variant 14 may include the product according to any one of variants 10-13 and may include a power unit and a torque converter. The power unit may drive the first pulley through the torque converter.

[0042] Variant 15 may include the product according to variant 14 and may include a drive wheel and a gear mechanism. The second pulley may be connected to the drive wheel through the gear mechanism.

[0043] The foregoing description of alternative selections within the scope of the present invention is merely illustrative in nature, and thus, variations or modifications thereof are not to be regarded as departing from the spirit and scope of the present invention.

Claims

1. A product, the product comprises: a rotary pulley having a first pulley half and a second pulley half, wherein the distance between the first pulley half and the second pulley half is variable; a screw actuator having a screw engaging the first pulley half; and a motor connected to the screw and operable to move the first pulley half via the screw to change the distance.

2. The product according to claim 1, wherein, the screw actuator includes a planetary roller meshing with the screw and a nut meshing with the planetary roller, wherein the motor drives the nut to rotate the planetary roller, which linearly moves the screw.

3. The product according to claim 2, further comprising a planetary gear set having a sun gear, planetary gears meshing with the sun gear, and a ring gear meshing with the planetary gears, the planetary gear set being connected between the motor and the nut and providing a gear reduction from the motor to the nut.

4. The product according to claim 3, wherein, the motor includes a rotor having a shaft, the shaft being connected to the planetary gear set and to a brake, the brake engaging the shaft to hold the shaft from rotating and to fix the first pulley half in place.

5. The product according to claim 1, further comprising wheels drivable by the shown pulley.

6. The product according to claim 1, further comprising a power unit and a reverse drive unit configured to reverse-rotate the pulley, the power unit driving the pulley to rotate via the reverse drive unit.

7. The product according to claim 1, wherein, the screw actuator includes a plurality of planetary rollers meshing with the screw, and a nut meshing with the plurality of planetary rollers and surrounding the plurality of planetary rollers, wherein the nut has an internal gear meshing with the plurality of planetary rollers and an external gear driven by the motor.

8. The product according to claim 1, wherein, the pulley rotates on a shaft, and wherein the screw has a hollow center and the shaft extends through the hollow center of the screw.

9. A product, the product comprises: a first pulley; a second pulley drivingly connected to the first pulley via a connecting member, at least one of the first pulley or the second pulley having a first pulley half and an opposing second pulley half, and having a variable operating diameter produced by the movement of the first pulley half relative to the second pulley half; a screw actuator having a screw engaging the first pulley half; and a motor engaging the shown screw via a drive train, which produces a translation of the screw.

10. The product according to claim 9, the product further comprising a planetary roller meshing with the screw and a nut meshing with the planetary roller, wherein, the motor is connected to the screw via the nut and the planetary roller.

11. The product according to claim 10, wherein the product further comprises a double reduction planetary gear set connected between the motor and the nut.

12. The product according to claim 11, wherein, the motor includes a rotor having a shaft, the shaft is connected to the double reduction planetary gear set, and includes a brake, the brake engages the shaft to hold the shaft from rotating and to fix the first pulley half in place.

13. The product according to claim 10, wherein the product further comprises a power unit and a reverse drive unit, the reverse drive unit having a planetary gear set, and the power unit can drive the first pulley through the reverse drive unit.

14. The product according to claim 10, wherein the product further comprises a power unit and a torque converter, and the power unit drives the first pulley through the torque converter.

15. The product according to claim 14, wherein the product further comprises a drive wheel and a gear mechanism, and the second pulley is connected to the drive wheel through the gear mechanism.

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