JP6686401B2 - Friction roller reducer - Google Patents

Description

  The present invention relates to a friction roller type speed reducer.

  A friction roller type speed reducer for decelerating the rotation of an electric motor that rotates at high speed and transmitting the decelerated rotation to driving wheels is known (see, for example, Patent Document 1). The friction roller type speed reducer 501 shown in FIG. 7 disclosed in the same document has an input shaft 503, an output shaft 505, a pair of sun rollers 507A and 507B, a ring roller 509, a plurality of intermediate rollers 511, and a loading cam. And a device 513. The ring roller 509 is arranged concentrically with the sun rollers 507A and 507B, and is supported and fixed to a housing or the like (not shown). The inner peripheral surface 509a of the ring roller 509 is a rolling contact surface that is inclined in a direction in which the inner diameter increases toward the central portion in the axial direction. Further, the intermediate rollers 511 are arranged at a plurality of circumferential positions of the annular space 519 between the outer peripheral surfaces 507a of the sun rollers 507A and 507B and the inner peripheral surface 509a of the ring roller 509. An outer peripheral surface 511a of the intermediate roller 511 is a convex curved surface whose generatrix is a partially arcuate shape, and is adapted to make rolling contact with the outer peripheral surfaces 507a of the sun rollers 507A and 507B and the inner peripheral surface 509a of the ring roller 509, respectively. According to this friction roller type speed reducer 501, the revolution movement of the intermediate roller 511 to which the rotation of the input shaft 503 is transmitted can be taken out to the output shaft 505 via the carrier 515.

JP, 2013-104545, A

  In the structure of the friction roller type speed reducer 501 described above, the inner peripheral surface 509a of the ring roller 509 has a concave cross-section whose inner diameter increases toward the central portion in the axial direction. Therefore, in the ring roller 509, the traction oil is likely to collect on the traction surface having the concave cross section due to the centrifugal force during operation. When the traction oil stays on the traction surface, the exhaust heat is not effectively generated and the temperature of the traction surface rises. An increase in the temperature of the traction surface may cause a decrease in the traction coefficient, which may cause slippage of the speed reducer, such as slip, and the speed reducer characteristics may become unstable.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a friction roller type speed reducer in which a traction surface is appropriately cooled and stable speed reducer characteristics are obtained.

The present invention has the following configuration.
A sun roller arranged concentrically with the input shaft and having a rolling contact surface on the outer peripheral surface, a ring roller arranged concentrically with the sun roller around the sun roller and having a rolling contact surface on the inner peripheral surface, the sun roller and the ring roller A plurality of intermediate rollers that are rotatably supported between the sun roller and the ring roller and are in rolling contact with the rolling contact surfaces of the sun roller and the ring roller, respectively, a connecting member that connects the ring roller and the output shaft, and the rolling contact surface. And a loading cam mechanism that applies the pressing force of the friction roller type speed reducer,
The outer peripheral surface of the intermediate roller is a convex curved surface of which the generatrix is a partial arc,
The ring roller that rotates integrally with the output shaft is formed on an inner peripheral surface of the ring roller, and has a concave traction surface inclined in a direction in which the inner diameter increases toward the central portion in the axial direction, and a bottom portion of the concave traction surface. A friction roller type speed reducer, comprising: a traction oil discharge portion that is provided so as to penetrate an outer diameter surface of the ring roller.
The ring roller may have an escape groove formed at the bottom of the concave traction surface, and the traction oil discharge portion may be provided at the bottom of the escape groove.

  According to the friction roller type speed reducer of the present invention, the traction surface is appropriately cooled, and stable speed reducer characteristics can be obtained.

It is a sectional view of a friction roller type reduction gear of the 1st example of composition. FIG. 1A is a perspective view of the ring roller shown in FIG. 1, and FIG. 1B is a perspective view in which a part of the ring roller shown in FIG. It is sectional drawing of the friction roller type reduction gear of a 2nd structure example. 3A is a perspective view showing a state in which a pair of ring roller elements shown in FIG. 3 are separated from each other, and FIG. 3B is a perspective view showing a state in which a pair of ring roller elements shown in FIG. is there. (A) is a perspective view of a ring roller according to a modification, and (B) is a perspective view in which a part of the ring roller shown in (A) is cut away. (A) is a perspective view of a ring roller according to another modification, and (B) is a perspective view in which a part of the ring roller shown in (A) is cut away. It is sectional drawing of the conventional friction roller type reduction gear.

Hereinafter, each configuration example of the present invention will be described in detail with reference to the drawings.
(First configuration example)
FIG. 1 is a cross-sectional view of a friction roller type speed reducer of the first configuration example.
The friction roller type speed reducer 100 includes an input shaft 11, a sun roller 13 concentric with the input shaft 11, a ring roller 15, a plurality of intermediate rollers 17, an output shaft 19, a loading cam mechanism 21, and a ring. A connecting member 23 that connects the roller 15 and the output shaft 19 is provided.

  The friction roller type speed reducer 100 rotationally drives the sun roller 13 by an input shaft 11 connected to a drive shaft such as an electric motor (not shown). The rotation about the axis of the sun roller 13 is transmitted to the ring roller 15 via the plurality of intermediate rollers 17. The rotation of the ring roller 15 is taken out from the output shaft 19 via the connecting member 23.

  The sun roller 13 includes a pair of sun roller elements 25A and 25B arranged coaxially with each other. These sun roller elements 25A and 25B are sandwiched by a pair of loading cam mechanisms 21 from the outside in the axial direction.

  The sun roller elements 25A and 25B are arranged concentrically with the input shaft 11 around the tip of the input shaft 11. The sun roller elements 25A and 25B are arranged so as to be rotatable relative to the input shaft 11 and with a gap provided between the surfaces facing each other. Further, the pair of loading disks 27A and 27B forming the respective loading cam mechanisms 21 are located at two positions, that is, the intermediate portion of the input shaft 11 and the portion near the tip thereof, and the respective sun roller elements 25A and 25B are axially opposite to each other. It is provided at the sandwiching position. The loading disks 27A and 27B are arranged in a state in which axial displacement and rotation with respect to the input shaft 11 are blocked, and rotate in synchronization with the input shaft 11.

  Each of the loading disks 27A and 27B has its rear surfaces abutted against a step surface 29 formed in the intermediate portion of the input shaft 11 and a side surface of the loading nut 33 near the tip of the input shaft 11, It is positioned in the axial direction with respect to the input shaft 11. The driven-side cam surface 35 and the driving-side cam surface 37 are provided at a plurality of circumferential positions of the base end surfaces of the sun roller elements 25A and 25B and one side surface of the loading disks 27A and 27B, which are opposed to each other. There is. A ball 39 is sandwiched between these cam surfaces to form a loading cam mechanism 21. The shapes of the driven-side cam surface 35 and the driving-side cam surface 37 are such that the depth in the axial direction gradually changes in the circumferential direction, and they are deepest at the central portion in the circumferential direction and also become shallower toward both ends.

  The base end side of the input shaft 11 is supported around the shaft Ax1 via a ball bearing 41. The output shaft 19 is also supported on the same shaft Ax1. An oil supply passage 43 is formed in the input shaft 11 along the axial direction, and traction oil is supplied to the oil supply passage 43. The traction oil in the oil supply passage 43 is jetted and supplied toward each sliding portion from a jet port (not shown) extending in the radial direction.

2A is a perspective view of the ring roller shown in FIG. 1, and FIG. 2B is a perspective view in which a part of the ring roller shown in FIG. 1A is cut away.
The ring roller 15 is formed in an annular shape as a whole, and is arranged concentrically with the input shaft 11 and the sun roller 13 on the outer peripheral side of the sun roller 13 shown in FIG. The inner peripheral surface of the ring roller 15 is a concave traction surface 45 that is inclined in a direction in which the inner diameter increases toward the central portion in the axial direction. In the ring roller 15, this concave traction surface 45 is a rolling contact surface with the intermediate roller 17. The concave traction surface 45 works to suppress the side slip force of the ring roller 15. The ring roller 15 is supported by the connecting member 23 connected to the output shaft 19 shown in FIG. 1 while being fixed in the axial direction and the rotation direction, and rotates integrally with the output shaft 19.

  In this ring roller 15, a relief groove 47 for grinding is formed at the bottom of the concave traction surface 45. A plurality of holes 49 as traction oil discharge portions that penetrate the ring roller outer diameter surface 48 are provided in the bottom of the escape groove 47 in the circumferential direction. The traction oil supplied to the concave traction surface 45 of the ring roller 15 is discharged from the hole 49 to the outer diameter side of the ring roller. Further, the ring roller 15 does not hinder the grinding process of the concave traction surface 45 by providing the hole 49 at the bottom of the escape groove 47.

  As shown in FIG. 1, a plurality of intermediate rollers 17 are arranged along the circumferential direction in an annular space 51 between the outer peripheral surface of the sun roller 13 and the inner peripheral surface of the ring roller 15. The outer peripheral surface of the intermediate roller 17 makes rolling contact with the rolling contact surfaces of the sun roller 13 and the ring roller 15, respectively. The intermediate roller 17 is rotatably supported by the swing holder 55 about a rotation shaft Ax2 parallel to the input shaft 11, that is, a support shaft 53 serving as a rotation shaft.

  The swing holder 55 is swingably supported by the carrier 57, and rotatably supports the support shaft 53 of the intermediate roller 17 via a bearing 69. The outer peripheral surface of the intermediate roller 17 is a convex curved surface whose generatrix is a partial arc, and makes rolling contact with the outer peripheral surface of the sun roller 13 and the inner peripheral surface of the ring roller 15, respectively.

  The loading cam mechanism 21 is arranged on the outer side of the sun roller 13 in the axial direction, so that when torque is input to the input shaft 11, the rolling contact portions (tractions) of the peripheral surfaces of the sun roller 13, the ring roller 15, and the intermediate roller 17 are pulled. Part) to increase or decrease the pressing force.

  In the friction roller type speed reducer 100 of this configuration, the inner peripheral surface of the ring roller 15 is a concave traction surface 45 that is inclined in a direction in which the inner diameter increases toward the central portion in the axial direction. Therefore, when the speed reducer operates, the traction oil gathers at the bottom of the concave traction surface 45 due to the centrifugal force of the intermediate roller 17 and the ring roller 15. The traction oil collected at the bottom of the concave traction surface 45 is discharged to the outer diameter side of the ring roller through a hole 49 which is a traction oil discharge part provided at the bottom. Therefore, the traction oil does not stay at the bottom of the concave traction surface 45. The traction oil collected at the bottom of the concave traction surface 45 is always discharged to the outer diameter side of the ring roller through the hole 49, so that the ring roller 15 discharges heat (cools) by heat transfer through the traction oil. To be done. As a result, in the friction roller type speed reducer 100, a decrease in the traction coefficient is suppressed, and slippage of the speed reducer is less likely to occur.

(Second configuration example)
Next, the friction roller type speed reducer 200 of the second configuration example in which the ring roller 15 includes a pair of ring roller elements will be described.
FIG. 3 is a sectional view of the friction roller type speed reducer of the second configuration example. The same parts and members shown in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted or simplified.
The friction roller type speed reducer 200 of this configuration has a sun roller 79 arranged concentrically with the input shaft 11, a ring roller 81, a plurality of intermediate rollers 83, an output shaft 19, a loading cam mechanism 87, and a ring roller 81. And a connecting member 85 that connects the output shaft 19 with the output shaft 19.

  The sun roller 79 of this configuration example is a single roller having a solid structure integrally formed at one end of the input shaft 11 concentrically with the axis Ax1 of the input shaft 11. The outer peripheral surface of the sun roller 79 is formed into a concave curved surface whose outer peripheral shape in the axial cross section is a concave curve having a single arc shape.

  The ring roller 81 is a pair of ring roller elements arranged side by side in the axial direction, and includes a fixed ring roller element 89 and a movable ring roller element 91 movable in the axial direction. The fixed ring roller element 89 and the movable ring roller element 91 are arranged concentrically with the sun roller 79 on the outer peripheral side of the sun roller 79 while being housed inside the cup-shaped connecting member 85. The inner peripheral surfaces of the fixed ring roller element 89 and the movable ring roller element 91 are annular inclined surfaces that are inclined so that their inner diameters decrease from the inner end surface 82 facing each other toward the outer end surface 84 on the axially opposite side. There is. In other words, each inner peripheral surface of the fixed ring roller element 89 and the movable ring roller element 91 is formed as a concave traction surface 45 that is inclined in a direction in which the inner diameter increases toward the central portion in the axial direction. The concave traction surface 45 becomes a rolling contact surface on which the intermediate roller 83 rolls.

  The plurality of intermediate rollers 83 are supported by the support shaft 53 via needle bearings 95 so as to be rotatable about the rotation shaft Ax2 and displaceable in the axial direction. These intermediate rollers 83 are arranged between the outer peripheral surface of the sun roller 79 and the inner peripheral surface of the ring roller 81. Both ends of the support shaft 53 are supported by the swing holder 55. The swing holder 55 is supported by the carrier 57 so that the intermediate roller 83 can move (swing) in the radial direction of the input shaft 11. The carrier 57 is fixed to a motor body (not shown) by a fastening member.

  The outer peripheral surface of the intermediate roller 83 is a convex curved surface whose outer edge shape of the axial cross section is a convex curve having a single arc shape, and makes rolling contact with the outer peripheral surface of the sun roller 79 and the inner peripheral surface of the ring roller 81.

  The connecting member 85 is formed in a substantially disc shape and has a center portion connected to the output shaft 19. A connecting base end portion 97 extends axially from an outer peripheral edge of the connecting base end portion 97 and has a ring roller on an inner diameter side. And a cylindrical roller holding portion 99 for holding 81.

  On the inner peripheral portion of the roller holding portion 99, from the base end side, a corrugated plate-shaped preload spring 101, a loading disc 103, balls 105 as rolling elements, a movable ring roller element 91, a fixed ring roller element 89, and a retaining ring. 107 are assembled in this order.

  A plurality of recessed grooves 109 are formed in the inner peripheral portion of the roller holding portion 99 along the axial direction. Further, a ring groove 111 is formed in the circumferential direction on the inner peripheral part of the end of the roller holding part 99 opposite to the connecting base end part 97.

  The recessed groove 109 accommodates a plurality of radial projections 113 formed at a plurality of locations on the outer peripheral portion of the fixed ring roller element 89. The protrusion 113 of the fixed ring roller element 89 engages with the concave groove 109 of the roller holding portion 99 without any rattling in the rotation direction, and enables transmission of rotational torque between the roller holding portion 99 and the ring roller 81. To do.

  The retaining ring 107 is fitted into the ring groove 111. The retaining ring 107 regulates the axial position of the fixed ring roller element 89 and fixes the fixed ring roller element 89 to the roller holding portion 99.

  The loading disc 103 has a plurality of protrusions 115 that protrude radially outward from the outer peripheral portion thereof. The protrusions 115 of the loading disk 103 engage with the concave grooves 109 of the roller holding portion 99, respectively, similarly to the protrusions 113 of the fixed ring roller element 89.

  The loading disk 103 has an outer end surface on the output shaft side, in which a notch 117 is formed by cutting out a portion of the outer diameter side in an annular shape, and the preload spring 101 is mounted in the notch 117.

  The loading cam mechanism 87 includes a movable ring roller element 91, a loading disc 103, and balls 105 that are rolling elements. The loading cam mechanism 87 applies a pressing force to the rolling contact surfaces of the sun roller 79, the ring roller 81, and the intermediate roller 83.

  On the outer end surface of the movable ring roller element 91, a plurality of (for example, three) first cam grooves 119 are formed along the circumferential direction. The loading disk 103 is disposed so as to face the first cam groove 119, and a plurality of (for example, three) second cam grooves 121 are formed at circumferential positions corresponding to the first cam groove 119. The balls 105 are respectively sandwiched between the first cam groove 119 and the second cam groove 121.

  The axial groove depths of the first cam groove 119 and the second cam groove 121 are deepest in the central portion with respect to the circumferential direction and gradually change along the circumferential direction, so that the first cam groove 119 and the second cam groove 119 are formed. It becomes shallower toward the circumferential end of the groove 121.

  When the input shaft 11 is stopped, the balls 105 are located at the deepest part of each cam groove. In this state, the loading disk 103 is pressed toward the movable ring roller element side by the elastic force of the preload spring 101.

  When the input shaft 11 is rotationally driven, each ball 105 moves to a shallower portion of the first cam groove 119 and the second cam groove 121. As a result, an axial thrust that presses the movable ring roller element 91 toward the fixed ring roller element 89 is generated. The axial thrust generated by the loading cam mechanism 87 shortens the gap between the fixed ring roller element 89 and the movable ring roller element 91, whereby the inner peripheral surface of the ring roller 81 and the outer peripheral surface of each intermediate roller 83. The pressing force at the rolling contact part increases. Along with this, the pressing force of the rolling contact portion between the outer peripheral surface of the intermediate roller 83 and the outer peripheral surface of the sun roller 79 also increases. As a result, the pressing force of the plurality of rolling contact portions existing between the input shaft 11 and the output shaft 19 increases as the torque transmitted between the input shaft 11 and the output shaft 19 increases.

  When the loading cam mechanism 87 generates an axial thrust as described above, the intermediate roller 83 is displaced axially of the movable ring roller element 91 due to the elastic deformation of the traction components such as the ring roller 81 and the elastic deformation of each contact point. Accordingly, the fixed ring roller element 89 is axially displaced.

4A is a perspective view showing a state where the pair of ring roller elements shown in FIG. 3 are separated from each other, and FIG. 4B is a partially cutaway view showing a state where the pair of ring roller elements shown in FIG. 3 are close to each other. FIG.
The pair of fixed ring roller element 89 and movable ring roller element 91 are respectively provided in concave on inner end surfaces 82 facing each other, and have a groove 93 which is a traction oil discharge portion communicating from the concave traction surface 45 to the ring roller outer diameter surface 92. Have. That is, the grooves 93 are arranged radially on the inner end surfaces 82 of the fixed ring roller element 89 and the movable ring roller element 91 facing each other at the same position in the circumferential direction, and radially with respect to the axes of the ring roller elements 89, 91. It is provided. The groove 93 may be provided only on one of the fixed ring roller element 89 and the movable ring roller element 91.

  The friction roller type speed reducer 200 may be designed such that the fixed ring roller element 89 and the movable ring roller element 91 come into contact with each other when the torque input exceeds a certain level. In such a case, after the contact of the ring roller 81, the traction oil collects at the bottom of the concave traction surface 45 due to the centrifugal force of the intermediate roller 83 and the ring roller 81.

  However, in the friction roller type speed reducer 200 of this configuration, the traction oil collected at the bottom of the concave traction surface 45 passes through the groove 93, which is a traction oil discharge part provided at the bottom, to the outer diameter side of the ring roller. Is discharged. Therefore, the traction oil does not stay at the bottom of the concave traction surface 45. The traction oil collected at the bottom of the ring roller 81 is constantly discharged to the outer diameter side of the ring roller through the hole 49, and thus heat is exhausted (cooled) by heat transfer through the traction oil. As a result, in the friction roller type speed reducer 200, a decrease in traction coefficient is suppressed, and slippage of the speed reducer such as slip is less likely to occur.

Next, a modified example of the friction roller type speed reducer 200 of the second configuration example will be described.
FIG. 5A is a perspective view of a ring roller according to a modification, and FIG. 5B is a perspective view in which a part of the ring roller shown in FIG. 5A is cut away.
In the friction roller type speed reducer of the modification, the collar 133 is fitted between the pair of fixed ring roller elements 129 and the movable ring roller element 131 of the ring roller 127 so as to be relatively rotatable. The collar 133 holds the coaxial axes of the fixed ring roller element 129 and the movable ring roller element 131 by fitting the inner peripheral surfaces of both ends in the axial direction to the outer circumferences of the fixed ring roller element 129 and the movable ring roller element 131. The collar 133 is provided with a hole 49 as a traction oil discharge portion. The hole 49 is provided at the center of the collar 133 in the direction along the axis of the collar 133 so as to penetrate from the collar inner diameter side to the outer diameter side. The fixed ring roller element 129 and the movable ring roller element 131 may be provided with the groove 93 described above. In that case, the effect of discharging the traction oil is enhanced.

  In this friction roller type speed reducer, when the speed reducer is operated, centrifugal force of the intermediate roller 83 and the ring roller 127 causes the traction oil to collect on the inner circumference of the collar 133 which is the bottom of the concave traction surface 45. The traction oil collected on the inner circumference of the collar 133 is discharged to the outer diameter side of the ring roller through a hole 49 provided in the collar 133. Therefore, the traction oil does not stay at the bottom of the concave traction surface 45. The ring roller 127 is discharged (cooled) by heat transfer through the traction oil, because the traction oil collected on the inner circumference of the collar 133 is constantly discharged to the outer diameter side of the ring roller through the hole 49. . As a result, in the friction roller type speed reducer, a decrease in the traction coefficient is suppressed, and a malfunction of the speed reducer such as slip is less likely to occur.

FIG. 6A is a perspective view of a ring roller according to another modification, and FIG. 6B is a perspective view in which a part of the ring roller shown in FIG. 6A is cut away.
In the friction roller type speed reducer of this modified example, a collar 141 for synchronizing the phase is engaged over the outer circumference between a pair of the fixed ring roller element 137 and the movable ring roller element 139 of the ring roller 135. The fixed ring roller element 137 and the movable ring roller element 139 are provided with splines 143 on their outer diameter surfaces, respectively. Further, a spline 145 that engages with the spline 143 of the fixed ring roller element 137 and the movable ring roller element 139 is formed on the inner diameter surface of the collar 141. As a result, the fixed ring roller element 137 and the movable ring roller element 139 are connected so as to be relatively displaceable in the axial direction and not relatively rotatable. Further, the collar 141 is provided with a hole 49 penetrating from the inner diameter side to the outer diameter side of the collar 141 at the center of the collar 141.

  In this friction roller type speed reducer, when the speed reducer is operated, centrifugal force of the intermediate roller 83 and the ring roller 135 causes the traction oil to collect on the inner circumference of the collar 141 which is the bottom of the concave traction surface 45. The traction oil collected on the inner circumference of the collar 141 is discharged to the outer diameter side of the ring roller through a hole 49 provided in the collar 141. Therefore, the traction oil does not stay at the bottom of the concave traction surface 45. In the ring roller 135, the traction oil collected on the inner circumference of the collar 141 is always discharged to the outer diameter side of the ring roller through the hole 49, so that heat can be transferred to the traction oil and discharged (cooled). Becomes As a result, in the friction roller type speed reducer, a decrease in the traction coefficient is suppressed, and a malfunction of the speed reducer such as slip is less likely to occur.

  The friction roller type speed reducer having each of the above configurations can be suitably used for a drive device of an electric vehicle used in, for example, an electric vehicle, a hybrid vehicle, or an electric four-wheel drive vehicle.

  The present invention is not limited to the above-described embodiments, and the configurations of the embodiments may be combined with each other, or may be modified and applied by those skilled in the art based on the description of the specification and well-known techniques. The invention is planned and is included in the scope of protection required.

  For example, the balls forming the loading cam mechanism may be replaced with rollers. Further, as the retaining ring, other means capable of transmitting the axial force such as a cotter can be used.

As described above, the following items are disclosed in this specification.
(1) A sun roller arranged concentrically with the input shaft and having a rolling contact surface on the outer peripheral surface, a ring roller arranged concentrically with the sun roller around the sun roller and having a rolling contact surface on the inner peripheral surface, and the sun roller. A plurality of intermediate rollers that are rotatably supported between the ring roller and are in rolling contact with the rolling contact surfaces of the sun roller and the ring roller, respectively, and a connecting member that connects the ring roller and the output shaft, A friction roller type speed reducer comprising: a loading cam mechanism that applies a pressing force to a rolling contact surface,
The ring roller is formed on an inner peripheral surface of the ring roller, and has a concave traction surface inclined in a direction in which the inner diameter increases toward the central portion in the axial direction, and penetrates the ring roller outer diameter surface from the bottom of the concave traction surface. And a traction oil discharge part provided on the friction roller type speed reducer.
According to this friction roller type speed reducer, the inner peripheral surface of the ring roller 15 becomes the concave traction surface 45 inclined in the direction in which the inner diameter increases toward the central portion in the axial direction. When the friction roller type speed reducer operates, the traction oil gathers at the bottom of the concave traction surface 45 due to the centrifugal force of the intermediate roller 17 and the ring roller 15. The traction oil collected at the bottom passes through the hole 49 of the traction oil discharge part provided at the bottom and is discharged to the outer diameter side of the ring roller. Therefore, the traction oil does not stay at the bottom of the concave traction surface 45. The traction oil collected at the bottom of the ring roller 15 is constantly discharged to the outer diameter side of the ring roller through the hole 49, so that heat can be discharged (cooled) by heat transfer via the traction oil. As a result, in the friction roller type speed reducer, a decrease in the traction coefficient is suppressed, and a malfunction of the speed reducer such as slip is less likely to occur. Further, since a plurality of traction oil discharge parts are provided in the circumferential direction, the effect of discharging traction is further enhanced.

(2) A sun roller arranged concentrically with the input shaft and having a rolling contact surface on the outer peripheral surface, a ring roller arranged concentrically with the sun roller around the sun roller and having a rolling contact surface on the inner peripheral surface, and the sun roller. A plurality of intermediate rollers that are rotatably supported between the ring roller and are in rolling contact with the rolling contact surfaces of the sun roller and the ring roller, respectively, and a connecting member that connects the ring roller and the output shaft, A friction roller type speed reducer comprising: a loading cam mechanism that applies a pressing force to a rolling contact surface,
The ring roller has a pair of ring roller elements arranged side by side in the axial direction of the input shaft,
The pair of ring roller elements each have a concave traction surface formed so that each inner peripheral surface is inclined in a direction in which the inner diameter increases toward the central portion in the axial direction,
At least one of the inner end surfaces of the pair of ring roller elements that face each other has a traction oil discharge portion that communicates from the concave traction surface to the ring roller outer diameter surface.
According to the friction roller type speed reducer 200, in the pair of ring roller elements, the inner peripheral surface of the ring roller 81 becomes the concave traction surface 45 that is inclined in the direction in which the inner diameter increases toward the central portion in the axial direction. When the friction roller type speed reducer 200 has a torque input above a certain level and a pair of ring roller elements contact each other, after the ring roller 81 abuts, the traction oil is a concave traction due to the centrifugal force of the intermediate roller 83 and the ring roller 81. Gather at the bottom of face 45. The traction oil collected at the bottom passes through the groove 93, which is a traction oil discharge section, and is discharged to the outer diameter side of the ring roller. Therefore, the traction oil does not stay at the bottom of the concave traction surface 45. The traction oil collected at the bottom of the ring roller 81 is constantly discharged to the outer diameter side of the ring roller through the hole 49, so that heat can be discharged (cooled) by heat transfer via the traction oil. As a result, in the friction roller type speed reducer, a decrease in the traction coefficient is suppressed, and a malfunction of the speed reducer such as slip is less likely to occur.

(3) In the friction roller type speed reducer according to (2), a collar that holds the pair of ring roller elements coaxially is provided between the pair of ring roller elements over the outer circumference of the pair of ring roller elements. The friction roller type speed reducer is characterized in that the traction oil discharge portion includes a hole provided in a central portion of the collar and penetrating to an outer diameter side of the collar.
According to this friction roller type speed reducer, the traction oil collected on the inner periphery of the collar 133 is discharged to the outer diameter side of the collar through the holes 49 provided in the collar 133. Therefore, the traction oil does not stay at the bottom of the concave traction surface 45.

(4) In the friction roller type speed reducer according to (2), a collar that synchronizes a phase between the pair of ring roller elements is provided between the pair of ring roller elements on an outer periphery of the pair of ring roller elements. A friction roller type speed reducer, which is engaged across, and wherein the traction oil discharge portion includes a hole provided in a central portion of the collar and penetrating to an outer diameter side of the collar.
According to this friction roller type speed reducer, the traction oil collected on the inner circumference of the collar 141 is discharged to the outer diameter side of the collar through the hole 49 provided in the collar 141. Therefore, the traction oil does not stay at the bottom of the concave traction surface 45.

11 Input Shaft 13 Sun Roller 15 Ring Roller 17 Intermediate Roller 19 Output Shaft 21 Loading Cam Mechanism 23 Connecting Member 25A, 25B Sun Roller Element 27A, 27B Loading Disc 45 Concave Traction Surface 49 Hole (Traction Oil Discharge Portion)
100 Friction roller reducer Ax2 Rotating shaft

Claims (2)

A sun roller arranged concentrically with the input shaft and having a rolling contact surface on the outer peripheral surface, a ring roller arranged concentrically with the sun roller around the sun roller and having a rolling contact surface on the inner peripheral surface, the sun roller and the ring roller A plurality of intermediate rollers that are rotatably supported between the sun roller and the ring roller and are in rolling contact with the rolling contact surfaces of the sun roller and the ring roller, respectively, a connecting member that connects the ring roller and the output shaft, and the rolling contact surface. And a loading cam mechanism that applies the pressing force of the friction roller type speed reducer,
The outer peripheral surface of the intermediate roller is a convex curved surface of which the generatrix is a partial arc,
The ring roller that rotates integrally with the output shaft is formed on an inner peripheral surface of the ring roller, and has a concave traction surface inclined in a direction in which the inner diameter increases toward the central portion in the axial direction, and a bottom portion of the concave traction surface. A friction roller type speed reducer, comprising: a traction oil discharge portion that is provided so as to penetrate an outer diameter surface of the ring roller.   The ring roller has an escape groove formed at the bottom of the concave traction surface,
  The friction roller reducer according to claim 1, wherein the traction oil discharge portion is provided at a bottom portion of the clearance groove.

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