JP6221918B2 - Planetary roller traction drive device - Google Patents

Description

  The present invention relates to a planetary roller traction drive device in which a pinion roller is sandwiched between a sun roller and a ring roller.

  Conventionally, for example, a planetary roller traction drive device as described in Patent Document 1 is known. This planetary roller type traction drive device has a cam ring that rotates integrally with a sun roller, and power is transmitted through a rolling element provided between the sun roller and a cam surface formed facing the cam ring. ing.

  In the traction drive mechanism, torque is transmitted using the shear force of the oil film by applying a pressing force (force in the normal direction) to the contact portion via the oil film between the rollers. In the planetary roller traction drive device described in Patent Document 1, as described above, a pressing force corresponding to an input torque is obtained by using a torque cam mechanism including a cam surface and rolling elements.

JP 2004-116670 A

  By the way, in the planetary roller traction drive device, the pressing force of the contact portion with respect to the input torque is uniquely determined by the design of the torque cam mechanism. However, since the traction coefficient of the traction oil that forms an oil film between the rollers varies depending on the oil temperature, the required pressing force varies depending on the oil temperature of the traction oil. Therefore, in the method of obtaining the pressing force according to the input torque, the pressing force is generally set on the assumption that the oil temperature is high, that is, the most slippery condition. For this reason, under conditions where the oil temperature is low, a pressing force is excessively applied to the contact portion, and torque transmission is hindered, resulting in a decrease in transmission efficiency.

  The present invention has been created in view of such a point, and an object thereof is to provide a planetary roller traction drive device with improved transmission efficiency.

In order to achieve the above object, the present invention employs the following technical means.
The planetary roller traction drive device of the present invention includes a housing, an input shaft, a sun roller, a ring roller, a pinion roller, a carrier, a cam mechanism, and an axial distance changing means.

The input shaft is rotatably supported by the housing. The sun roller is provided so as to be able to transmit rotation to the input shaft, has a tapered outer wall surface that forms a predetermined angle with respect to the axial direction of the input shaft, and is movable relative to the housing in the axial direction. Ring roller is an annular member which is provided radially outward relative to the sun roller has a tapered inner wall surface forming a predetermined angle with respect to the axial direction of the input shaft, and engaging in the direction of rotation in the housing, It can move relative to the housing in the axial direction.

  The pinion roller has a tapered outer wall surface circumscribing the outer wall surface of the sun roller and inscribed in the inner wall surface of the ring roller, and is movable relative to the housing in the radial direction. The carrier supports the pinion roller so that the pinion roller can rotate about the axis of the pinion roller and can revolve around the sun roller, and outputs the revolution component of the pinion roller to the outside.

  The cam mechanism connects the input shaft and the sun roller, or the housing and the ring roller so as to be able to transmit the rotation, and is connected to the first cam surface formed integrally with one of the two connected members, A second cam surface formed integrally with the other member; and a rolling element provided between the first cam surface and the second cam surface. The axial distance changing means can change the axial distance between the first cam surface and the second cam surface. The cam mechanism changes the axial component of the force transmitted from one of the first cam surface and the second cam surface to the other in accordance with the axial distance.

  According to this configuration, by changing the axial distance between the first cam surface and the second cam surface by the axial distance changing means, the axial direction amount generated on the cam surface when transmission torque is applied to the input shaft. The force can be made different even with the same transmission torque. The axial component force in the cam mechanism acts as a pressing force at the contact portion (tapered outer wall surface or inner wall surface) of each roller. For this reason, for example, by adjusting the axial distance according to conditions such as oil temperature that greatly affects the sliding of the contact portion, a suitable axial component force according to the operating conditions can be obtained. Furthermore, an appropriate pressing force can be applied, and the power transmission efficiency in the planetary roller traction drive device can be improved.

1 is a cross-sectional view schematically showing an entire planetary roller traction drive device according to a first embodiment of the present invention. II-II sectional view taken on the line of FIG. III-III sectional view taken on the line of FIG. 1 is a cross-sectional view schematically showing an entire planetary roller traction drive device according to a first embodiment of the present invention. VV line sectional view of FIG. VI-VI sectional view taken on the line of FIG. The graph which shows the relationship between input torque and thrust force. The flowchart which shows hydraulic pressure variable control. The figure which shows the relationship between required thrust force and oil_pressure | hydraulic. Sectional drawing which shows typically the whole planetary roller type traction drive apparatus which concerns on 2nd Embodiment of this invention. Sectional drawing which shows typically the whole planetary roller type traction drive apparatus which concerns on 2nd Embodiment of this invention. The flowchart which shows the fluid force variable control which concerns on other embodiment.

<First Embodiment>
[Constitution]
A first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a planetary roller traction drive device 101 according to this embodiment rotates to an input shaft 30 via a housing 70, an input shaft 30 rotatably supported by the housing 70, and a torque cam mechanism 5. And a sun roller 40 provided so as to be able to transmit. Further, a pair of ring rollers 10 and 20 provided on the outer side in the radial direction of the sun roller 40, a plurality of pinion rollers 50 inscribed in the ring rollers 10 and 20 and circumscribed in the sun roller 40, and the pinion rollers 50 are rotated and revolved. And freely supporting carriers 60 and 61. In the present invention, “externally” and “inscribed” mean a state in which an oil film is interposed so as to be able to transmit rotation.

The central axes L of the sun roller 40, the ring rollers 10 and 20, and the carriers 60 and 61 coincide with each other. The rotation center axis when the pinion roller 50 rotates is parallel to the center axis L of the sun roller 40. The plurality of pinion rollers 50 are arranged at substantially equal intervals with respect to the circumferential direction of the sun roller 40. The input shaft 30 is connected to, for example, a motor (not shown) and is driven to rotate. A part of the input shaft 30 and the rollers 10 , 20 , 40, 50 are accommodated in the housing 70. Furthermore, each of the ring rollers 10 and 20 and the sun roller 40 can move relative to the housing 70 in the axial direction, and the pinion roller 50 can move relative to the housing 70 in the radial direction. Hereinafter, each member will be described in detail.

  The first ring roller 10 and the second ring roller 20 have an annular shape and are arranged to face each other with an interval in the axial direction, and the first ring roller 10 is located on one side of the second ring roller 20 (FIG. 1). On the left side). Each of the ring rollers 10 and 20 is engaged with the housing 70 via a plurality of coil springs 81 in a state where the rotation is restricted. The coil spring 81 is provided so as to be parallel and extendable in the axial direction, and the ring rollers 10 and 20 are slidable in the axial direction.

  Concave portions 11 that are continuous in the circumferential direction are formed on the outer peripheral surface of the first ring roller 10 and on the end facing the second ring roller 20. Similarly, a concave portion 21 that is continuous in the circumferential direction is formed on the outer peripheral surface of the second ring roller 20 on the end facing the first ring roller 10. A pressure chamber 13 is formed by the recesses 11 and 21. The pressure chamber 13 is connected to a hydraulic circuit 14 including an oil pump, a pressure regulating valve and the like (not shown), and the hydraulic circuit 14 is connected to a control device 15 (control means). The control device 15 is an ECU that includes, for example, a CPU, a ROM, a RAM, etc., and can perform various arithmetic processes and outputs to each output device. The control function of the planetary roller traction drive device 101 of the present embodiment is It governs. The force acting on each of the ring rollers 10 and 20 from the pressure chamber 13 can be adjusted by adjusting the hydraulic pressure (fluid pressure) in the pressure chamber 13 by the control device 15.

  On the inner peripheral surface of the first ring roller 10, a first ring-side tapered surface portion 12 whose inner diameter gradually increases from one side in the axial direction to the other side (left side to right side in FIG. 1) is formed. On the inner peripheral surface of the second ring roller 20, a second ring-side tapered surface portion 22 whose inner diameter gradually decreases from one side to the other side in the axial direction is formed. The taper angle (inclination angle with respect to the axial direction) of the first ring side taper surface portion 12 is equal to the taper angle of the second ring side taper surface portion 22. The 1st ring side taper surface part 12 and the 2nd ring side taper surface part 22 are equivalent to the "inner wall surface of a ring roller" as described in a claim.

  On the outer peripheral surface of each pinion roller 50, a first pinion side tapered surface portion 51 whose outer diameter gradually increases from one side in the axial direction to the other side, and an outer diameter gradually decreases from one side in the axial direction to the other side. The second pinion-side tapered surface portion 52 is formed at an interval in the axial direction, and the first pinion-side tapered surface portion 51 is on one side in the axial direction from the second pinion-side tapered surface portion 52 (the left side in FIG. 1). ). The taper angle of the first pinion side taper surface 51 is equal to the taper angle of the second pinion side taper surface 52, and the maximum and minimum outer diameters of the pinion side taper surfaces 51 and 52 are equal. .

  And the 1st ring side taper surface part 12 and the 1st pinion side taper surface part 51, the 2nd ring side taper surface part 22, and the 2nd pinion side taper surface part 52 come into contact, respectively. The taper angle of each pinion side taper surface part 51 and 52 is substantially equal to the taper angle of each ring side taper surface part 12 and 22 which contacts. The 1st pinion side taper surface part 51 and the 2nd pinion side taper surface part 52 are corresponded to the "outer wall surface of a pinion roller" as described in a claim.

  Further, a cylindrical surface portion 53 is formed on the outer peripheral surface of the pinion roller 50. The cylindrical surface portion 53 is disposed between the pinion-side tapered surface portions 51 and 52 and is continuous with the other end portion of the first pinion-side tapered surface portion 51 and one end portion of the second pinion-side tapered surface portion 52.

  The sun roller 40 includes a sun shaft 41 as a shaft portion provided on the input shaft 30 side and a sun roller portion 42 having a truncated cone shape. A sun-side tapered surface portion 43 is formed on the outer peripheral surface of the sun roller portion 42 so that the outer diameter gradually decreases from one side to the other side in the axial direction. The taper angle of the sun side taper surface portion 43 is substantially equal to that of the first pinion side taper surface portion 51. And this sun side taper surface part 43 and the 1st pinion side taper surface part 51 contact. The sun-side tapered surface portion 43 corresponds to an “outer wall surface of the sun roller” recited in the claims.

  The carriers 60 and 61 support the pinion roller 50 from both sides in the axial direction. The first carrier 60 disposed on one side (left side in FIG. 1) of the pinion roller 50 and the other side of the pinion roller 50 (FIG. 1). And the second carrier 61 arranged on the right side. The first carrier 60 has a cylindrical part 62 located on the outer peripheral side of the input shaft 30 and a flange part 63. The second carrier 61 has an output shaft 64 and a flange portion 65, and holes 66 are formed in the flange portions 63 and 65 at equal intervals in the circumferential direction. The hole 66 is formed to be slightly larger in the radial direction than the pinion roller support shaft 67, and the pinion roller support shaft 67 is inserted into the hole 66 so that the pinion roller 50 can rotate around the pinion roller support shaft 67. While supporting, it supports so that revolution around the sun axis 41 is possible. As a result, the revolution component of the pinion roller 50 is output to the output shaft 64.

  Next, the torque cam mechanism 5, which is the main part of the present invention, will be described in detail with reference to FIGS. 2 and 5, only the sun shaft 41 of the sun roller 40 is shown, and the carriers 60 and 61 are omitted.

As shown in FIG. 2, a plurality of (four in this embodiment) grooves 44 are formed at equal intervals in the circumferential direction on the input shaft side end surface of the sun shaft 41. The groove 44 has a part of an annular shape (center angle of about 45 degrees), and has a flat bottom portion 45 and a cam surface 46 ( second cam surface) continuous from the bottom portion 45. The cam surface 46 is formed in a convex curved surface (curvature radius constant) rising from the bottom 45, and the rising tip is the same as the end surface of the sun shaft 41. Further, as shown in FIG. 3, a groove 34 (bottom 35 and cam surface 36 ( first cam surface)) is similarly formed on the end surface of the input shaft 30 on the sun axis side. A cam 9 (rolling element) having a spherical shape is provided.

  Here, the lead angle θ is a tangential plane (M1, M2) at a contact point (for example, D1, D2) on the cam surfaces 36, 46 of the cam 9, and a vertical plane that passes through the contact point and is perpendicular to the axial direction. The angle formed by (N1, N2). For example, in the embodiment shown in FIG. 3, the tangent plane M1 (first tangent plane) at the contact point D1 (first contact point) between the cam 9 and the cam surface 46 passes through the contact point D1 and is perpendicular to the axial direction. The angle formed with the vertical surface N1 (first vertical surface) which is a plane is the lead angle θ1. In the embodiment shown in FIG. 6, the tangent plane M2 (second tangent plane) at the contact point D2 (second contact point) between the cam 9 and the cam surface 46 passes through the contact point D2 and is perpendicular to the axial direction. The angle formed by the vertical surface N2 (second vertical surface) that is a plane is the lead angle θ2.

  Each of the cam surfaces 36 and 46 has a shape that swells from the bottom portions 35 and 45 toward the facing surface so that the lead angle θ gradually decreases. In other words, the cam surface 36 is formed so that the lead angle θ varies depending on the position from the end surface of the input shaft 30, and the cam surface 46 is formed so that the lead angle θ varies depending on the position from the end surface of the sun shaft 41. ing. Thus, since each cam surface 36 and 46 is formed in the convex curved surface, the cam 9 contacts the cam surfaces 36 and 46 by the lead angle (theta) which changes with contact positions. The cam 9 comes into contact with the cam surfaces 36 and 46 in the range of the lead angle θ from the maximum angle θ1 (FIG. 3) to the minimum angle θ2 (FIG. 5) during power transmission.

  Further, in the present embodiment, the pressure chamber 13, the hydraulic circuit 14, and the coil spring 81 constitute axial distance changing means 8 (see FIG. 1) that changes the axial distance Q of the cam surfaces 36 and 46. (Details will be described later). Note that the planetary roller traction drive device 101 of this embodiment restrains the rotation of the ring rollers 10 and 20 to reduce the rotational speed between the sun roller 40 and the carriers 60 and 61 to transmit power. Functions as a deceleration mechanism.

[Action]
Next, the operation of the planetary roller traction drive device 101 in the present embodiment will be described mainly focusing on the operation of the torque cam mechanism 5.

First, when the input shaft 30 is rotationally driven and the input torque T is transmitted to the torque cam mechanism 5, the cam 9 moves in the circumferential direction along the cam surfaces 36 and 46. Then, the circumferential force (force Fc1 shown in FIG. 3, force Fc2 shown in FIG. 6) acting on the input torque T and the thrust force F (force F1 shown in FIG. 3, force shown in FIG. 6) determined by the lead angle θ. F2) occurs. The thrust force F is an axial cam thrust and is an axial component of the force (force Ft1 shown in FIG. 3 and force Ft2 shown in FIG. 6) transmitted between the cam surfaces 36 and 46. Due to the action of this thrust force F, the pressing force (force in the normal direction) required for power transmission is applied to each traction contact portion (the contact portion between the first ring side taper surface portion 12 and the first pinion side taper surface portion 51, the second force). The contact portion between the ring-side taper surface portion 22 and the second pinion-side taper surface portion 52 and the contact portion between the first pinion-side taper surface portion 51 and the sun-side taper surface portion 43 (hereinafter simply referred to as “contact portion”). . The thrust force F is given by the following equation (1).
F = T / (rtanθ) (1)

  Here, r is a radius from the center of the sun axis 41 to the contact points D1 and D2. When power is transmitted by the torque cam mechanism 5, a thrust force F corresponding to the input torque T is generated. Further, since the size is determined by the lead angle θ at the contact point of the cam 9, for example, when the cam 9 contacts at the lead angle θ1 as shown in FIG. The force F is given by a graph indicated by a solid line in FIG.

  Next, the operation of the planetary roller traction drive device 101 when the hydraulic pressure in the pressure chamber 13 is increased will be described. FIG. 4 is a cross-sectional view schematically showing the entire planetary roller traction drive device 101 according to the first embodiment as in FIG. 1, but a mode in which the hydraulic pressure in the pressure chamber 13 is larger than that in FIG. FIG. When the hydraulic pressure in the pressure chamber 13 is increased, the ring rollers 10 and 20 are moved away from each other in the axial direction by the hydraulic pressure. At this time, the coil spring contracts in the axial direction. Further, each pinion roller 50 moves radially outward, and the sun roller 40 (sun shaft 41) moves to the other side (right side in FIG. 1). Accordingly, as shown in FIGS. 5 and 6, in the torque cam mechanism 5, the cam 9 moves along the cam surfaces 36 and 46, and the contact position thereof changes. For example, the lead angle θ2 as shown in FIG. Contact with. At this time, a gap (axial distance Q) is generated between the opposed surfaces of the sun shaft 41 and the input shaft 30. At this time, the thrust force F obtained with respect to the input torque T is given by a graph indicated by a one-dot chain line in FIG.

  As shown in FIG. 7, in the present embodiment, for the same input torque T, different thrust force F is obtained depending on the lead angle θ of the contact position of the cam 9 with respect to the cam surfaces 36 and 46. Further, as the lead angle θ at the contact position is smaller, a larger thrust force F can be obtained (θ1> θ2, F1 <F2).

  Next, an operation for reducing the hydraulic pressure in the pressure chamber 13 will be described. When the hydraulic pressure in the pressure chamber 13 is reduced, the restoring force of the coil spring 81 acts in a direction that brings the ring rollers 10 and 20 closer to each other in the axial direction, so that each ring roller 10 and 20 moves in a direction closer to each other in the axial direction. To do. Furthermore, each pinion roller 50 moves radially inward, and the sun roller 40 and the sun shaft 41 move to one side (left side in FIG. 4). Along with this, the cam 9 moves along the cam surfaces 36 and 46 and comes into contact with the lead angle θ1, for example.

  Next, the variable hydraulic control of the planetary roller traction drive device 101 in this embodiment will be described. The hydraulic pressure variable control is executed by the control device 15. As shown in FIG. 8, first, the output shaft rotational speed Nout and the input shaft rotational speed Nin are detected (step S1), and then based on the detected output shaft rotational speed Nout, the input shaft rotational speed Nin, and the reduction ratio Rs. The measured slip ratio Sr is calculated (step S2). The measured slip rate Sr is calculated from the output shaft rotational speed Nout and the input shaft rotational speed Nin as the degree of slip occurring at the contact portion between the rollers 10, 20, 40, and 50 in the current operating state. Is.

  Then, the hydraulic pressure P of the pressure chamber 13 is calculated based on the actually measured slip ratio Sr and the target slip ratio St (step S3). The hydraulic pressure P is calculated by multiplying the difference between the target slip ratio St and the actually measured slip ratio Sr by, for example, a predetermined coefficient K.

  Here, when the slip is large (when the measured slip ratio Sr is larger than the target slip ratio St), the hydraulic pressure P is set to be large. Conversely, when the slip is small (when the difference between the actually measured slip ratio Sr and the target slip ratio St is small), the hydraulic pressure P is set small.

  Then, control according to the calculated oil pressure P is performed (step S4). This hydraulic pressure variable control routine is repeated every predetermined time, and the hydraulic pressure P of the pressure chamber 13 is reset as appropriate.

[effect]
In the traction drive mechanism, it is possible to transmit torque using the shear force of the oil film by applying a pressing force to the contact portion of each roller 10, 20, 40, 50 through the oil film. In such a traction drive mechanism, it is necessary to apply a pressing force (normal force) necessary for torque transmission so that excessive slip (slip) does not occur at each contact portion. In the present embodiment, it is possible to apply a pressing force to each contact portion by the torque cam mechanism 5 that applies the axial thrust (thrust force F). Accordingly, a traction force can be generated at the contact portion, and torque can be transmitted between the sun roller 40 and each pinion roller 50 and between each pinion roller 50 and each ring roller 10, 20.

  Furthermore, the pressing force applied to each contact portion can be changed according to the input torque T by the torque cam mechanism 5. In addition, the axial distance Q between the cam surfaces 36 and 46 can be changed by the axial distance changing means 8, and the cam surfaces 36 and 46 are formed in a convex curved surface, so that the lead depends on the position where the cam 9 contacts. The angle θ is varied. Therefore, different thrust forces F can be obtained with respect to the same input torque T (see FIG. 7). Also, since the cam surfaces 36 and 46 have a gently convex curved shape, the cam 9 can smoothly roll. Become.

  Furthermore, in this embodiment, the pressing force acting on the contact portion of each roller 10, 20, 40, 50 is changed by adjusting the hydraulic pressure P of the pressure chamber 13 according to the actually measured slip ratio Sr in the operation state. ing. For example, the slip at each contact portion is easily affected by the oil temperature, and the required pressing force differs between the oil temperature of 80 degrees and the oil temperature of 20 degrees. When the oil temperature is 80 degrees, the rollers are very slippery, and a large pressing force is required. On the other hand, when the oil temperature is 20 degrees, the sliding force hardly occurs and the pressing force may be small.

  According to the hydraulic pressure variable control of the present embodiment, for example, when the slip is large, the pressing force is increased by increasing the hydraulic pressure P. Conversely, when the slip is small, the pressing force is reduced by reducing the hydraulic pressure P. For this reason, a suitable pressing force can always be maintained according to the operation state of the planetary roller type traction drive device 101.

  As described above, the power transmission efficiency can be improved by maintaining a suitable pressing force in the case where the slip is appropriately maintained such as when the load is low and the oil temperature is low. Moreover, since it is not necessary to add unnecessary hydraulic pressure P, the wear of the contact portion can be reduced, and the life of the apparatus can be extended.

  FIG. 9 is a graph showing the relationship between the required thrust force F and the hydraulic pressure P of the pressure chamber 13, wherein the relationship in the present embodiment is indicated by a solid line, and the relationship in the comparative embodiment is indicated by a broken line. In the comparative embodiment, the pressure is applied directly by the pressure control device from the direction orthogonal to the axial direction to increase the pressing force between the rollers. This is different from the method of adding the thrust force F.

  As shown in FIG. 9, in this embodiment, the force required to generate the same thrust force F may be smaller than in the comparative embodiment. That is, since the force acting on the pressure chamber 13 functioning as a pressure control device can be reduced, the strength of the portion receiving the pressure can be designed low, and the device can be miniaturized.

Second Embodiment
Next, the planetary roller traction drive device 102 of the second embodiment will be described with reference to FIGS. In addition, about the structure similar to 1st Embodiment, it shows with the same code | symbol and abbreviate | omits description. The present embodiment is different from the first embodiment in that the torque cam mechanism 6 is provided at a portion where the ring rollers 1 and 2 and the housing 7 are opposed to each other. Hereinafter, parts different from the first embodiment will be described.

  In the present embodiment, a pressure chamber 16 is formed in the outer peripheral portion of the input shaft 3. Further, a sun-side tapered surface portion 47 whose outer diameter gradually increases from one side to the other side in the axial direction is formed on the outer peripheral surface of the sun roller 40. The taper angle of the sun side taper surface portion 47 is substantially equal to that of the second pinion side taper surface portion 52. And this sun side taper surface part 47 and the 2nd pinion side taper surface part 52 contact.

  A coil spring 82 is provided in parallel to the axial direction at the other end (right side in FIG. 10) of the sun roller 4. The inner diameter portion of the sun roller 4 and the outer diameter portion of the input shaft 3 are connected by a key, a spline, or the like, so that the sun roller 4 can slide relative to the input shaft 3. In this configuration, the axial distance changing means 18 for changing the axial distance Q between the cam surfaces 36 and 46 is constituted by the pressure chamber 16, the hydraulic circuit 14, the sun roller 4, and the coil spring 82.

  Next, the operation of the planetary roller traction drive device 102 when the hydraulic pressure in the pressure chamber 16 is increased will be described. When the hydraulic pressure is applied to the pressure chamber 16, the sun roller 4 moves to the other side in the axial direction (the right side in FIG. 10). Accordingly, each pinion roller 50 moves inward in the radial direction, and each ring roller 1, 2 moves in a direction approaching each other in the axial direction.

  As a result, as shown in FIG. 11, the gap (axial distance Q) between the housing 7 and each of the ring rollers 1 and 2 is increased, and the cam 9 provided between the opposing surfaces moves. The torque cam mechanism 6 provided on the facing surface of the housing 7 and each of the ring rollers 1 and 2 is the same as that in the first embodiment, and thus detailed description thereof is omitted. According to this embodiment, the same effect as that of the first embodiment can be obtained.

<Other embodiments>
In each of the above embodiments, the cam 9 is in contact with each of the cam surfaces 36 and 46 in the range where the lead angle θ is in the range of θ1 to θ2 in accordance with the hydraulic pressure P. You may make it contact only in two points | pieces, (theta) 1 and lead angle (theta) 2. In this case, as shown in FIG. 12, after calculating the actually measured slip ratio Sr (step S2), it is determined whether or not the actually measured slip ratio Sr is equal to or less than the target slip ratio St (step S5). If the measured slip rate Sr is equal to or less than the target slip rate St (step S5: YES), the hydraulic pressure is turned off (step S6). If the measured slip rate Sr is larger than the target slip rate St (step S5: NO), the hydraulic pressure is turned on (step S7).

  At this time, for example, when the hydraulic pressure is OFF, the cam 9 is in contact with the cam surfaces 36 and 46 at a lead angle θ1, and when the hydraulic pressure is ON, the cam 9 is at a lead angle θ2 and each cam surface 36 is in contact. , 46 can be set to contact with each other. In this configuration, when the measured slip rate Sr is low and it is not necessary to increase the thrust force F (pressing force), the hydraulic pressure P is not applied to the pressure chambers 13 and 16 (step S6), and the measured slip rate Sr is high. When it is necessary to increase the thrust force F (pressing force), the hydraulic pressure P is applied to the pressure chambers 13 and 16 (step S7). Thus, according to this configuration, it is possible to obtain a suitable pressing force with easier control.

  In each of the above embodiments, each cam surface 36, 46 may be formed as a convex curved surface with a constant curvature radius. Moreover, it may not be a curved surface as long as it can be contacted at different lead angles θ, and for example, it may have a shape constituted by a plurality of planes having different inclination angles.

  In each of the above embodiments, the actually measured slip ratio Sr is calculated based on the output shaft rotational speed Nout and the input shaft rotational speed Nin (step 2). For example, the actually measured slip ratio Sr may be calculated based on the oil temperature. good.

  Alternatively, since the slip is easily affected by the oil temperature, the oil pressure P may be determined based on the detected oil temperature. In this case, the oil pressure P can be set large when the oil temperature is high, and the oil pressure P can be set small when the oil temperature is low.

  In each of the above embodiments, the pressure chambers 13 and 16 are provided by hydraulic pressure, but instead, for example, the ring rollers 1, 2, 10, and 20 are separated and approached in the axial direction by motor drive. May be.

In the first embodiment, the torque cam mechanism 5 may be provided between the sun shaft 41 and the sun roller portion 42 of the sun roller 40.
The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit of the invention.

1, 10 First ring roller 2, 20 Second ring roller 3, 30 Input shaft 4, 40 Sun roller 5, 6 Torque cam mechanism (cam mechanism)
7, 70 Housing 8, 18 Axial distance changing means 9 Cam (rolling element)
12 1st ring side taper surface (inner wall surface)
22 Second ring side taper surface (inner wall surface)
36 Cam surface (first cam surface)
43, 47 Sun side taper surface (outer wall surface)
46 Cam surface (second cam surface)
50 Pinion roller 51 First pinion side taper surface (outer wall surface)
52 Second pinion side taper surface (outer wall surface)
60, 61 Carrier 101 Planetary roller type traction drive device F1, F2 Thrust force (Axial component force)

Claims (8)

A housing (7, 70);
An input shaft (3, 30) rotatably supported by the housing;
A sun roller that is provided so as to be able to transmit rotation to the input shaft, has a tapered outer wall surface (43, 47) that forms a predetermined angle with respect to the axial direction of the input shaft, and is relatively movable in the axial direction relative to the housing (4, 40),
An annular member provided radially outward with respect to the sun roller, having a tapered inner wall surface (12, 22) that forms a predetermined angle with respect to the axial direction of the input shaft, and the housing in the rotational direction. engaged, and the relative axial movable ring roller (10,20,1,2) to said housing,
A pinion roller that has a tapered outer wall surface (51, 52) circumscribing the outer wall surface of the sun roller and inscribed in the inner wall surface of the ring roller, and is relatively movable in the radial direction with respect to the housing 50),
A carrier (60, 61) for supporting the pinion roller rotatably around the axis of the pinion roller and revolving around the sun roller, and outputting the revolution component of the pinion roller to the outside;
The input shaft and the sun roller, or the housing and the ring roller are connected so as to be able to transmit rotation, and a first cam surface (36) formed integrally with one of the two connected members, and the connection A second cam surface (46) formed integrally with the other of the two members, and a rolling element (9) provided between the first cam surface and the second cam surface. A cam mechanism (5, 6);
Axial distance changing means (8, 18) capable of changing an axial distance (Q) between the first cam surface and the second cam surface;
With
The cam mechanism changes an axial component force (F1, F2) of a force (Ft1, Ft2) transmitted from one of the first cam surface and the second cam surface to the other according to the axial distance. Planetary roller type traction drive device (101, 102) characterized in that. Tangent planes (M1, M2) at contact points (D1, D2) on the first cam surface and the second cam surface of the rolling element, and a vertical plane (N1) passing through the contact points and perpendicular to the axial direction , N2) is the lead angle,
2. The planetary roller traction drive device according to claim 1, wherein the rolling element contacts the first cam surface and the second cam surface at different lead angles depending on a contact position .   The planetary roller traction drive device according to claim 1 or 2, wherein the first cam surface and the second cam surface are convex curved surfaces that are convex toward the rolling element.   4. The planetary roller traction drive device according to claim 3, wherein radii of curvature of the first cam surface and the second cam surface are constant. The cam mechanism connects the input shaft and the sun roller so as to be able to transmit rotation,
The axial distance changing means moves the ring roller relative to the housing in the axial direction when changing the axial distance,
The pinion roller moves relative to the housing in the radial direction when the ring roller moves relative to the housing in the axial direction,
5. The sun roller moves relative to the housing in the axial direction when the pinion roller moves relative to the housing in the radial direction. 6. Planetary roller type traction drive device.   The planetary roller traction drive device according to any one of claims 1 to 5, wherein the rolling element has a spherical shape. The axial distance changing means has a pressure chamber (13, 16) for generating a fluid pressure (P) capable of moving either the ring roller or the sun roller relative to the housing in the axial direction,
The planetary roller according to any one of claims 1 to 6, further comprising control means (15) for determining the fluid pressure and controlling the operation of the axial distance changing means. Traction drive device. An output shaft (64) connected to the carrier;
The control means includes
A measured slip ratio (Sr) is calculated based on the rotation speed (Nin) of the input shaft and the rotation speed (Nout) of the output shaft, and the measured slip ratio and a target slip ratio (St) set in advance as a target value. The planetary roller traction drive device according to claim 7, wherein the fluid pressure is determined based on:

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