JP6589531B2 - Friction roller reducer - Google Patents

Description

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

  A friction roller type speed reducer is known as a speed reducer that decelerates the rotation of the input shaft and transmits it to the output shaft (see, for example, Patent Document 1). The friction roller type speed reducer is disposed concentrically with the sun roller. And a plurality of intermediate rollers rotatably supported between the outer peripheral surface of the sun roller and the inner peripheral surface of the ring roller. The sun roller is composed of a pair of sun roller elements, and changes the pressing force on the traction surface of each roller by causing one sun roller element to approach or separate from the other sun roller element in the axial direction according to the transmission torque.

JP2013-104545A

In the conventional friction roller type reduction gear, the straight line L ₀ connecting the swing shaft 317 of the swing holder 319 and the support shaft 321 of the intermediate roller 315 is schematically shown in FIG. , inclined from the tangent _{L a} at the contact point _{P a} of the sun roller 311 and the intermediate roller 315. Therefore, when torque is transmitted by the speed reducer, the tangential force F1 or F2 at the contact point Pa acts on the support shaft 321 of the intermediate roller 315, and the component forces of the tangential forces F1 and F2 are applied to the traction surface of the intermediate roller 315. Works. Then, imbalance in the contact surface pressure is generated at the contact point _{P b} of the contact point _{P a} and the ring roller 313 with the sun roller 311. This imbalance in contact surface pressure is known to cause a reduction in the durability of the speed reducer and the occurrence of slip. To prevent the contact surface pressure becomes unbalanced, it is necessary to collimate the straight line L ₀ and the tangential line L _a of the. However, such an arrangement has a problem that, depending on the size of each roller, the arm portion of the swinging holder 319 and the ring roller 313 interfere with each other and the roller layout is not established.

Therefore, as shown in FIG. 18, it is conceivable to arrange the swing axis 325 at a position eccentric from the roller rotation axis 323 in the pair of bearing holding portions 322 and 322 that support the intermediate roller 315. That is, the outer peripheral surfaces of the bearing holding portions 322 and 322 having a circular shaft section are rotatably inserted into the shaft holes 330 formed in the frames 331 and 333, and the bearing holding portions 322 and 322 are inserted into the support shafts of the intermediate roller 315. It is assumed that the support structure 329 is supported at a position eccentric from the swing axis 325. In that case, the central axis of the outer peripheral surface of the bearing holding portion 322 becomes the swing axis 325. According to this support structure, since it is possible to lay out the swing axis 325 to the side surface 315a in the region of the intermediate rollers 315, it can be made parallel to and the tangent L _a straight line L ₀ as described above.

  However, in the support structure of the intermediate roller 315 shown in FIG. 18, the bearing holding portions 322 and 322 on both sides in the axial direction of the intermediate roller 315 are caused to swing, so that the bearing holding portions 322 and 322 are relatively twisted. There is a fear. When relative torsion occurs, the intermediate roller 315 tilts with respect to the sun roller rotation axis, and slippage within the contact ellipse on the traction surface increases, thereby reducing power transmission efficiency.

  The present invention has been made in view of the above-described matters, and the object of the present invention is to create an imbalance in the surface pressure at the contact point between the sun roller, the ring roller, and the intermediate roller without causing the intermediate roller to tilt. It is an object of the present invention to provide a friction roller type reduction gear that can be prevented.

The present invention has the following configuration.
(1) A sun roller connected to the input shaft, a ring roller arranged concentrically with the sun roller on the outer peripheral side of the sun roller, connected to the output shaft, an outer peripheral surface of the sun roller, and an inner peripheral surface of the ring roller A plurality of intermediate rollers that are in rolling contact with each other, are rotatably supported, a plurality of swing holders that are provided on each of the plurality of intermediate rollers, and support the rotation shaft of the intermediate rollers, and the plurality of swing holders A friction roller type speed reducer comprising:
The swing holder is provided at both end portions of the rotation shaft, each of which has a pair of bearing holding portions formed with support holes for supporting the end portions of the rotation shaft, and the pair of bearing holding portions. A bridging portion that is connected across the outer periphery,
The bearing holding portion has an oscillating shaft outer peripheral surface centered on the oscillating shaft at a position eccentric from the rotation shaft by a length equal to or less than the radius of the intermediate roller,
The carrier has a holder support portion that rotatably supports the outer peripheral surface of the swing shaft,
A pair of the bridging portions are disposed with the rotation shaft interposed therebetween, and a friction roller type reduction gear.
(2) The friction roller type reduction gear according to (1), further comprising a loading cam mechanism that applies a pressing force between the sun roller and the intermediate roller in accordance with a magnitude of a transmission torque.

  According to the present invention, it is possible to prevent imbalance in the surface pressure at the contact point between the sun roller, the ring roller, and the intermediate roller without causing the intermediate roller to tilt.

It is a partial cross section perspective view of a friction roller type reduction gear. It is a principal part expanded sectional view of a friction roller type reduction gear. It is a top view of the movable ring roller element which shows the cam groove of a loading cam mechanism. FIG. 4 is a cross-sectional view taken along line AA of FIG. 3, showing a state (A) in which the loading cam mechanism does not generate axial thrust and a state (B) in which axial thrust is generated. It is a disassembled perspective view of a rocking | fluctuation holder and a carrier. It is a perspective view of the rocking | holding holder which supports an intermediate | middle roller. It is a fragmentary sectional perspective view which shows the support structure of the intermediate roller which notched a rocking | fluctuation holder and a part of carrier. It is a side view of a carrier. It is a side view which shows the reference | standard state of a rocking | fluctuation holder and an intermediate | middle roller, and the state after rocking | fluctuation. It is a division | segmentation perspective view which shows the carrier and intermediate | middle roller of the friction roller type reduction gear of a 2nd structural example. It is a front view which shows the assembly state of a carrier in a partial cross section. It is a perspective view which shows the state which the rocking | fluctuation holder in which the intermediate roller was assembled | attached to the flange part. It is a division | segmentation perspective view which shows the carrier and intermediate | middle roller of the friction roller type reduction gear of a 3rd structural example. It is a disassembled perspective view of a carrier. It is an expansion perspective view of a pillar part tip piece. It is a partial front view of the carrier which shows the assembly state of a carrier in a partial cross section. It is explanatory drawing which shows typically arrangement | positioning of each roller of the conventional friction roller type reduction gear. It is explanatory drawing which shows the structure which has arrange | positioned the rocking | fluctuation axis line in the position eccentrically | centered from the roller rotating axis in a pair of bearing holding part which supports the conventional intermediate roller.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Basic configuration of friction roller reducer>
FIG. 1 is a partial sectional perspective view of a friction roller type speed reducer. As shown in FIG. 1, in the friction roller type speed reducer 100, the input shaft 11 and the output shaft 13 are arranged concentrically and transmit the rotational force input from the input shaft 11 to the output shaft 13. The friction roller type speed reducer 100 includes a sun roller 15 connected to the input shaft 11, a ring roller 17, a plurality of intermediate rollers 19, a connecting portion 21 for connecting the ring roller 17 to the output shaft 13, and a loading cam mechanism. 23.

  The friction roller type speed reducer 100 is provided on each of the plurality of intermediate rollers 19, and includes a swing holder 25 that rotatably supports a pair of support shafts 19 </ b> B and 19 </ b> B (spinning shaft) of the intermediate roller 19, and a plurality of And a carrier 27 that supports the swing holder 25. The swing holder 25 has a pair of bearing holding portions 28 that support the support shafts 19B and 19B, respectively. The bearing holding portion 28 has an outer peripheral surface centering on a position eccentric from the support shafts 19 </ b> B and 19 </ b> B, and the outer peripheral surface is inserted into a shaft hole formed in the carrier 27.

  In the friction roller type speed reducer 100 configured as described above, the rotation from the input shaft 11 is transmitted to the plurality of intermediate rollers 19 via the sun roller 15 to rotate the plurality of intermediate rollers 19. Each intermediate roller 19 is supported by the carrier 27 via the swing holder 25, and rotates while being supported by the swing holder 25 without rotating around the sun roller 15. The rotation of the intermediate roller 19 is transmitted to the ring roller 17, and the ring roller 17 rotates the output shaft 13 via the connecting portion 21. Thereby, the rotation from the input shaft 11 is decelerated and transmitted to the output shaft 13. Further, the pressing force on the traction surface of each roller is changed by the loading cam mechanism 23 in accordance with the rotational torque from the input shaft 11. Thereby, the power transmission efficiency of the friction roller type reduction gear 100 improves.

  The swing holder 25 is supported so as to be swingable and displaceable with respect to the carrier with the position eccentric from the support shaft 19B as the swing center. In this configuration, the rocking center of the rocking holder 25 is disposed in a region within the outer diameter of the bearing holding portion 28, and the bearing holding portions 28 and 28 are connected by bridging portions 75A and 75B described later to be integrated. It becomes. Thereby, the relative twist of the bearing holding portions 28 and 28 is suppressed, and the occurrence of tilt between the rollers is prevented.

Hereinafter, the structure of each part in the friction roller type reduction gear 100 is demonstrated sequentially.
FIG. 2 is an enlarged cross-sectional view of a main part of the friction roller type speed reducer 100.
The sun roller 15 is a solid structure roller formed integrally with the input shaft 11. The sun roller 15 is disposed concentrically with the input shaft 11 at one end of the input shaft 11. The outer peripheral surface 15a of the sun roller 15 is formed in a concave curved surface in which the outer edge shape of the axial section is a single circular arc-shaped concave curve.

  The ring roller 17 is a pair of ring roller elements arranged in parallel in the axial direction of the input shaft 11 and the output shaft 13 (hereinafter simply referred to as the axial direction), and moves in the axial direction with the fixed ring roller element 29. And a freely movable ring roller element 31. Each of the ring roller elements 29 and 31 is disposed concentrically with the sun roller 15 on the outer peripheral side of the sun roller 15 in the connecting portion 21 formed in a bottomed cylindrical shape.

  The inner peripheral surfaces 29a, 31a of the fixed ring roller element 29 and the movable ring roller element 31 are annular inclined surfaces in which the outer edge shape of the shaft cross section is linear. These inclined surfaces shorten the distance from the opposite side end surfaces 33, 35 of the ring roller elements 29, 31 to the outer end surfaces 37, 39 on the opposite side in the axial direction to the center of rotation of the intermediate roller 19. It is an inclined surface. The inner peripheral surfaces 29a and 31a are not limited to the inclined surfaces, but may be concave curved surfaces in which the outer edge shape of the axial cross section is a single arc-shaped concave curve.

  The plurality of intermediate rollers 19 are disposed in an annular space between the outer peripheral surface 15 a of the sun roller 15 and the inner peripheral surface 17 a of the ring roller 17. The outer peripheral surface 19a of the intermediate roller 19 is a convex curved surface in which the outer edge shape of the axial section is a single circular arc-shaped convex curve.

  The outer peripheral surface 15a of the sun roller 15, the inner peripheral surface 17a of the ring roller 17, and the outer peripheral surface 19a of the intermediate roller 19 are traction surfaces that are in rolling contact with each other.

  The connecting portion 21 is formed in a substantially disc shape and has a base end portion 41 whose central portion is connected to the output shaft 13, and extends in the axial direction from the outer peripheral edge of the base end portion 41. Etc., and a cylindrical roller holding portion 43 for holding the like. By connecting the roller holding portion 43 to the base end portion 41, the connecting portion 21 has the above-described bottomed cylindrical shape (cup shape) with the base end portion 41 as a bottom portion.

  The base end portion 41 is formed by, for example, a cutting process such as a lathe process, and the roller holding unit 43 is formed by a plastic process such as press molding. Thereby, the axial center of the base end part 41 and the roller holding | maintenance part 43 corresponds at low cost and with high precision.

  On the inner peripheral side of the roller holding portion 43, a corrugated preload spring 45, a cam ring 49, a ball 51 as a rolling element, a movable ring roller element 31, and a fixed ring are arranged in this order from the base end 41 side along the axial direction. A roller element 29 and a retaining ring 53 are arranged.

  A concave groove 55 is formed in the inner peripheral surface of the roller holding portion 43 along the axial direction. The concave grooves 55 are formed at a plurality of locations along the circumferential direction of the inner peripheral surface of the roller holding portion 43. On the outer periphery of the fixed ring roller element 29, protrusions 57 projecting radially outward are formed at a plurality of locations along the circumferential direction. On the outer periphery of the cam ring 49, protrusions 59 protruding radially outward are formed at a plurality of locations along the circumferential direction. And the protrusion 57 of the fixed ring roller element 29 and the protrusion 59 of the cam ring 49 are accommodated in the groove 55 of the roller holding part 43, and each protrusion 57, 59 is a groove in the state where there is no rattling in the rotation direction. 55 is engaged. Thereby, it is possible to transmit the rotational torque between the roller holding portion 43 and the ring roller 17 and the cam ring 49.

  Further, the cam ring 49 is formed with a notch 61 in which a part on the outer diameter side is notched in an annular shape on the outer end surface on the output shaft 13 side. A preload spring 45 that presses the cam ring 49 toward the input shaft 11 is attached to the notch 61.

  A ring groove 63 (see FIG. 1) is formed along the circumferential direction on the inner peripheral surface of the tip end portion of the roller holding portion 43 opposite to the base end portion 41. A retaining ring 53 is fitted into the ring groove 63. The retaining ring 53 fixes the fixed ring roller element 29 to the roller holding portion 43 in a state where the axial position is restricted.

<Loading cam mechanism>
Next, the loading cam mechanism 23 will be described.
The movable ring roller element 31, the cam ring 49, and the ball 51 shown in FIG. 2 constitute a loading cam mechanism 23. The loading cam mechanism 23 applies a pressing force proportional to the magnitude of the transmission torque to the traction surfaces of the sun roller 15, the ring roller 17, and the intermediate roller 19.

  FIG. 3 is a plan view of the movable ring roller element 31 showing the cam groove of the loading cam mechanism 23. Note that the shape and arrangement of the cam grooves shown in FIG.

  A plurality of (three in the illustrated example) first cam grooves 65 are formed in the outer end surface 39 of the movable ring roller element 31 along the circumferential direction. As shown in FIG. 2, the second cam groove 67 is similarly formed on the end surface of the cam ring 49 facing the movable ring roller element 31. In other words, a plurality of (three in the illustrated example) second cam grooves 67 are formed facing the first cam grooves 65 at circumferential positions of the cam ring 49 corresponding to the first cam grooves 65 of the movable ring roller element 31. Is done. The balls 51 are sandwiched between the first cam grooves 65 and the second cam grooves 67, respectively.

  The axial groove depths of the first cam groove 65 and the second cam groove 67 are deepest at the center in the circumferential direction and gradually change along the circumferential direction. It becomes shallower toward the direction end.

  4 is a cross-sectional view taken along the line A-A in FIG. 3, showing a state (A) where the loading cam mechanism 23 does not generate axial thrust and a state (B) where axial thrust is generated. It is. In a state where no torque is applied to the input shaft 11, each ball 51 is disposed at the deepest part of each cam groove 65, 67 as shown in FIG. In this state, the cam ring 49 is pressed toward the movable ring roller element 31 by the elastic force of the preload spring 45 (see FIG. 2).

  When torque is applied to the input shaft 11, each ball 51 moves to a shallow portion of each cam groove 65, 67 as shown in FIG. This generates an axial thrust that presses the movable ring roller element 31 toward the fixed ring roller element 29.

  When the loading cam mechanism 23 generates axial thrust, the movable ring roller element 31 shown in FIG. 2 moves to the fixed ring roller element 29 side, and the interval between the fixed ring roller element 29 and the movable ring roller element 31 is reduced. Then, the contact position between the inclined surfaces of the inner peripheral surfaces 29a and 31a of the ring roller 17 and the outer peripheral surface 19a of the convex curved surface of the intermediate roller 19 changes, and the traction surfaces of the ring roller 17, the intermediate roller 19 and the sun roller 15 change. The pressing force at each increases. As a result, as the transmission torque between the input shaft 11 and the output shaft 13 increases, the pressing force on the plurality of traction surfaces existing between the input shaft 11 and the output shaft 13 increases.

  As described above, when the loading cam mechanism 23 generates axial thrust, the pressing force on each traction surface increases, and each roller is elastically deformed. Further, the intermediate roller 19 is displaced toward the fixed ring roller element 29 as the movable ring roller element 31 is displaced in the axial direction.

<Supporting form of intermediate roller to carrier>
Next, the support form of the intermediate roller 19 will be described.
5 is an exploded perspective view of the swing holder 25 and the carrier, FIG. 6 is a perspective view of the swing holder that supports the intermediate roller 19, and FIG. 7 is an intermediate roller 19 with a part of the swing holder 25 and the carrier 27 cut out. It is a fragmentary sectional perspective view which shows the support structure. In the following description, the same or corresponding members as those described above are given the same reference numerals, and the description thereof is simplified or omitted.

  As shown in FIG. 5, the carrier 27 that supports the swinging holder 25 to which the intermediate roller 19 is assembled has a first carrier member 27A and a second carrier member 27B. The first carrier member 27A and the second carrier member 27B each have a ring-shaped bottom portion 85 and column portions 87 provided upright at a plurality of locations (three locations in the illustrated example) that are equally spaced in the circumferential direction of the bottom portion 85. Have.

  The column part 87 of the first carrier member 27A and the column part 87 of the second carrier member 27B are formed with insertion holes 89 along the axial direction. Although not shown, a bolt is inserted into each insertion hole 89, and the carrier 27 is attached to a motor body (not shown) or the like in a state where the corresponding tip portions of the column portions 87 and 97 are abutted against each other by the bolt. Fixed.

  Between the columnar portions 87 arranged in the circumferential direction, the above-described swinging holder 25 that rotatably supports the intermediate roller 19 is disposed. The swing holder 25 is assembled in a state of being sandwiched in the axial direction by the first carrier member 27A and the second carrier member 27B. As shown in FIG. 6, the swing holder 25 is provided with a pair of bearing holding portions 28 at both ends of the rotation shaft of the intermediate roller 19. As shown in FIG. 7, these bearing holding portions 28 are inserted into holder support portions 69 formed on the first carrier member 27 </ b> A and the second carrier member 27 </ b> B, and the swing holder 25 is centered on the outer peripheral surface of the bearing holding portion 28. The first carrier member 27 </ b> A and the second carrier member 27 </ b> B are swingably supported around the line as the rotation axis.

  The intermediate roller 19 includes a roller main body 19A having an outer peripheral surface 19a serving as a traction surface, and a pair of support shafts 19B and 19B extending outward in the axial direction from both end surfaces of the roller main body 19A. The intermediate roller 19 is a solid body in which a roller body 19A and a pair of support shafts 19B and 19B are integrally formed.

  The pair of support shafts 19B and 19B are rotatably supported by the swing holder 25, respectively. The swing holder 25 is provided independently for each of the plurality of intermediate rollers 19, and one intermediate roller 19 is supported by each swing holder 25. The swing holder 25 has a pair of support shafts 19B and 19B attached to the carrier 27 (see FIG. 1) in parallel with the input shaft 11.

The swing holder 25 has a pair of bearing holding portions 28 and 28 provided at both ends on the outer side in the axial direction of the support shafts 19B and 19B. The bearing holding portion 28 has a support hole 71 into which the support shaft 19 </ b> B is inserted, and a swing shaft outer peripheral surface 73 supported by the holder support portion 69 of the carrier 27. As shown in FIG. 6, the swing shaft outer peripheral surface 73 is formed so that the shaft section is circular, and the circle center (rotation center axis) of this shaft section is the swing center of the swing holder 25 (swing axis A _XO ). It becomes. The swing axis A _XO is disposed at a position eccentric from the rotation axis A _XR of the support shaft 19B by a predetermined distance.

  The swing holder 25 has a pair of bridging portions 75A and 75B that are arranged with the pair of bearing holding portions 28 and 28 straddling the outer periphery of the intermediate roller 19 and sandwiching the support shaft 19B.

  The bridging portion 75A includes arm portions 77A1 and 77A2 and connecting columns 79A1 and 79A2, and the bridging portion 75B includes arm portions 77B1 and 77B2 and connecting columns 79B1 and 79B2.

  The arm portion 77A1 of the bridging portion 75A extends from the inside of the bearing holding portion facing the end surface of the intermediate roller 19 in one bearing holding portion 28 toward the radially outer side of the intermediate roller 19. The connecting column 79A1 extends from the distal end portion of the arm portion 77A1 opposite to the bearing holding portion 28 in a direction orthogonal to the extending direction of the arm portion 75A1.

  The arm portion 77A2 extends from the inside of the bearing holding portion facing the end surface of the intermediate roller 19 in the other bearing holding portion 28 toward the radially outer side of the intermediate roller 19 in parallel with the extending direction of the arm portion 77A1. Is done. The connecting column 79A2 extends from the distal end portion of the arm portion 77A2 opposite to the bearing holding portion 28 in a direction orthogonal to the extending direction of the arm portion 75A2. The connecting pillars 79A1 and 79A2 are fixed to each other with fixing bolts 84 inserted into fixing holes 81 formed in the connecting pillars 79A1 and 79A2 shown in FIG. The

  Similarly, the bridging portion 75B has arm portions 77B1 and 77B2 and connecting columns 79B1 and 79B2, and arm portions 77B1 and 77B2 are extended from the bearing holding portion 28. It is extended. These connecting pillars 79B1 and 79B2 are fastened by fixing bolts with their ends being butted together.

  That is, the bridging portion 75A and the bridging portion 75B are disposed to face each other with the support shaft 19B interposed therebetween, and are rigidly joined to the pair of bearing holding portions 83 and 83. The bridging portions 75A and 75B support a pair of bearing holding portions 83 and 83 by forming a rigid frame structure that is a rectangular frame in the axial section of the support shaft 19B. With this ramen structure, the pair of bearing holding portions 83 and 83 are joined to each other in a state of strong rigidity, and become a structure that is not easily deformed. For this reason, even if a load that causes an axial shift is applied between the swing holder 25 and the support shaft 19B, relative torsion of the bearing holding portions 83 and 83 is suppressed, and the axial direction (input shaft, output shaft) is applied to the support shaft 19B. The inclination from the axial direction) is less likely to occur. As a result, the intermediate roller 19 is not tilted (tilted) with respect to the rotation shafts of the sun roller 15 and the ring roller 17, thereby causing a problem such as an increase in rotational torque due to mutual friction.

Next, a structure in which the intermediate roller 19 is rotatably supported by the bearing holding portion 28 will be described.
As shown in FIG. 7, in the holder support portion 69 formed on the first carrier member 27A, one bearing holding portion 83 of the swing holder 25 is inserted, and the one bearing holding portion 83 is rotatably supported. In the holder support portion 69 formed on the second carrier member 27B, the other bearing holding portion 83 of the swing holder 25 is inserted, and the other bearing holding portion 83 is rotatably supported. Each of the pair of holder support portions 69 is a blind hole with one end closed, and each is formed coaxially.

  The bearing holding portion 83 has a rocking shaft outer peripheral surface 73 having an outer diameter substantially the same as the inner diameter of the holder support portion 69 and is inserted into the holder support portion 69 with a clearance fit. Then, the bearing holding portion 83 rotates in the holder support portion 69 by sliding the swing shaft outer peripheral surface 73 and the inner peripheral surface of the holder support portion 69 in the circumferential direction. Thereby, the swing holder 25 is rotatably supported by the carrier 27.

  The support shaft 19 </ b> B of the intermediate roller 19 is supported by the support hole 71 of the bearing holding portion 83 via the needle bearing 91. The needle bearing 91 is a shell type needle bearing having a needle roller 93, a cage 95, and an outer ring 96, or a solid type needle bearing. The needle bearing 91 supports the intermediate roller 19 so as to be rotatable and movable in the axial direction. A ball bearing may be used instead of the needle bearing 91.

<Relationship between swing axis A _{XO of} swing holder and rotation axis A _{XR of} support shaft>
Next, the relationship between the swing axis A _XO of the swing holder 25 and the rotation axis A _XR of the support shaft 19B will be described.
FIG. 8 is a side view of the carrier 27. In the illustrated example, the bearing holding portion 83 of the swing holder 25 is inserted into the holder support portion 69 of the second carrier member 27 </ b> B, and the intermediate roller 19 is in contact with the sun roller 15.

Here, the tangent at the contact point P _a of the sun roller 15 and the intermediate roller 19 and the virtual line L _a, the normal line and the virtual line L _b. In the reference state before oscillation of the oscillating holder 25, the center _{O R} of the support shaft 19B (rotation axis _{A XR)} is in the line of the virtual line _{L b.} Swing center _{O OS} is the center of the shaft hole of the holder supporting portion 69 (pivot shaft _{A XO)} from the center _{O R} of the supporting shaft 19B in the reference state, lies on the tangent line _{L a} line parallel _{L C} .

FIG. 9 is a side view showing the reference state of the swing holder 25 and the intermediate roller 19 and the state after the swing. The pivot holder 25 in the reference state shown by dotted lines, the center _{O R} of the support shaft 19B is located on the straight line _{L C,} the center distance between the center _{O R} and the swing center _{O OS} on these straight line _{L C} is eccentric The amount r _OS .

When the pivot holder 25 is rotated by swing angle φ around the swing center O _OS, the center O _R of the support shaft 19B moves to a position away from the straight line L _C. That is, the center _{O R} of the support shaft 19B moves to the imaginary line _{L b} direction, whereby the intermediate roller 19, the position of the outer peripheral surface 19a is separated from the distance ΔH only the sun roller 15, the radial direction of the carrier 27 Protruding.

  As described above, when the bearing holding portion 83 of the swing holder 25 slides in the holder support portion 69 of the carrier 27 and the swing angle φ of the swing holder 25 changes, the intermediate roller 19 has a diameter of a distance ΔH. A displacement in the direction occurs. Further, when the swing holder 25 is changed to an inclination angle opposite to that in the illustrated example, the intermediate roller 19 is displaced in the direction opposite to that in the illustrated example. As a result, the intermediate roller 19 can protrude and retract in the radial direction of the carrier 27 in accordance with the transmission torque of the speed reducer.

Further, the swing center O _OS of the bearing holder 83, eccentricity r _OS and the center O _R of the support shaft 19B is in a curved shape radius (axial cross-sectional shape tapering toward the outside of the intermediate roller 19 Is a distance less than the maximum radius). Thereby, the bearing holding part 28 can be arranged with improved space efficiency without interfering with other members such as the sun roller 15 and the ring roller.

  In the assembly process of the friction roller type speed reducer 100 having this configuration, the sun roller 15 is inserted along the central axis of the carrier 27 from one axial end side of the carrier 27. When the sun roller 15 is inserted into the carrier 27, the outer edge shape of the sun roller 15 is a concave curved surface. Therefore, it is necessary to temporarily retract the intermediate roller 19 incorporated in the carrier 27 to the outer diameter side.

When retracting the intermediate roller 19 on the outer diameter side, comprising a pivot holder 25 that supports the intermediate roller 19, to rotate around the swing center O _OS. At this time, in order to prevent the swinging holder 25 and the intermediate roller 19 from interfering with the carrier 27, it is necessary to reduce the radial section of the column portion 87 provided on the carrier 27. Further, as the eccentric amount R _OS is shorter, the swing angle φ necessary for retracting the intermediate roller 19 becomes larger, and the radial section of the column portion 97 needs to be made smaller. However, if the radial cross section of the column portion 87 is reduced, the rigidity of the carrier 27 is reduced, and the degree of freedom in designing the lubricating oil passages and the like inside the column portion is reduced.

  Therefore, in the second configuration example of the friction roller type speed reducer shown below, the speed reducer can be assembled without greatly reducing the size of the radial section of the column portion 87.

<Second configuration example>
FIG. 10 is a divided perspective view showing the carrier and the intermediate roller of the friction roller type speed reducer of the second configuration example, and FIG. 11 is a front view showing a partially assembled state of the carrier.

  As shown in FIGS. 10 and 11, the carrier 27 having this configuration includes a carrier body 111 and a carrier cover 113. The carrier main body 111 has a cylindrical holder 115 and a flange portion 117. The cylindrical holder 115 rotatably supports the input shaft 11 to which the sun roller 15 is connected via a rolling bearing 119. In addition, the cylindrical holder 115 is integrally formed with an annular flange portion 117 extending outward in the radial direction at an end portion on the carrier cover 113 side. In the flange portion 117, the above-described holder support portion 69 and the insertion hole 89 are formed.

  The carrier cover 113 includes a ring-shaped bottom portion 85 and pillar portions 87 provided upright at a plurality of locations (three locations in the illustrated example) that are equally spaced in the circumferential direction of the bottom portion 85. Further, an insertion hole 89 is formed in the bottom portion 85, and a carrier 27 is fixed to the motor body or the like by inserting a bolt (not shown) into the insertion hole 89.

  In the carrier 27 having this configuration, first, as shown in FIG. 12, the swing holder 25 incorporating the intermediate roller 19 is assembled to the flange portion 117. Thereafter, the carrier cover 113 is assembled to the carrier body 111 with the swing holder 25 interposed therebetween. Therefore, when the swing holder 25 is assembled to the flange portion 117, the pillar portion is not provided on the flange portion 117, so that interference does not cause a problem even if the swing holder 25 is swung.

  On the other hand, the carrier cover 113 is provided with a pillar portion 87. The carrier cover 113 is formed along the axial direction of the carrier body 111 with the intermediate roller 19 assembled to the carrier body 111 in contact with the sun roller 15. Inserted. Therefore, the positional relationship between the column portion 87 and the swing holder 25 is such that the swing holder 25 is in a reference position indicated by a two-dot chain line in FIG. 9, and the distance between the column portion 87 and the swing holder 25 is long. As a result, the gap between the two becomes wider. Therefore, the column part 87 is inserted into the carrier main body 111 in a state in which interference hardly occurs, and the carrier cover 113 is assembled to the carrier main body 111. Thereby, the assembly of the carrier 27 is completed.

  According to this configuration, by providing the column part 87 only on the carrier cover 113 side, the swing holder 25 does not interfere with the column part 87 when the swing holder 25 is assembled to the carrier body 111. Therefore, it is possible to smoothly assemble the swing holder 25 to the carrier 27 without damaging the swing holder 25 and the column portion 87.

  During the operation of the speed reducer, the swing holder 25 swings autonomously. The swing range (the fluctuation range of the swing angle φ of the swing holder 25) is a roller by elastic deformation of each roller. This is accompanied by a change in position and is extremely small compared with the swing range in the assembly process. Therefore, the cross-sectional area in the radial cross section of the column part 87 is not greatly impaired.

<Third configuration example>
FIG. 13 is a divided perspective view showing the carrier and the intermediate roller of the friction roller type speed reducer of the third configuration example.
In the carrier 27 of this configuration, the plurality of column portions 87 of the third configuration example are divided into a column base portion 87A provided on the carrier cover 113A side and a column portion tip piece 87B provided on the carrier body 111A side. The When the column base 87A and the column tip 87B are combined with each other, the outer shape of the column 87 of the third configuration example described above is obtained.

  FIG. 14 is an exploded perspective view of the carrier. The columnar base 87A has a notch 121 formed at the inner diameter side tip. The notch 121 has a stepped end surface 123 formed at the intermediate portion in the axial direction of the columnar base 87A, and an inner peripheral surface 125 formed from the stepped end surface 123 toward the tip side. The columnar tip piece 87B is erected in the axial direction from one end surface of the carrier main body 111A toward the carrier cover 113A, and the outer peripheral surface 127 radially opposed to the inner peripheral surface 125, and the stepped portion. It has the end surface 123 and the front-end | tip surface 129 arrange | positioned facing an axial direction.

  FIG. 15 is an enlarged perspective view of the columnar tip piece 87B. The columnar tip piece 87B has an axial oil passage 131 drilled along the standing direction of the columnar tip piece 87B, and an opening 131a of the axial oil passage 131 is provided on the tip surface 129. A pair of oil grooves 133 </ b> A and 133 </ b> B are formed on the front end surface 129 from the opening 131 a toward the contact point between the sun roller 15 and the intermediate roller 19.

FIG. 16 is a partial front view of the carrier showing a partially assembled cross-sectional view of the carrier.
When the pair of oil grooves 133A and 133B of the columnar tip piece 87B are abutted against the stepped end surface 123 of the columnar base 87A, the oil grooves 133A and 133B and the stepped end surface 123 respectively define radial oil passages. The Lubricating oil is supplied from the axial oil passage 131 to each radial oil passage, and the supplied lubricating oil is discharged to the inner diameter side through the radial oil passage along the oil grooves 133A and 133B. The discharged lubricating oil is supplied to the contact point between the sun roller 15 and the intermediate roller 19 and lubricates the traction surface of each roller. The discharged lubricating oil is supplied to the ring roller 17 and is also used for lubrication with the ring roller 17.

  Compared to the case where the column portion is integrated, the above-described radial oil passage can simplify the processing for forming the oil passage, and chips and the like can be formed in the oil passage. Residuals are less likely to occur. Further, since the groove cross-sectional areas of the oil grooves 133A and 133B can be easily reduced, the adjustment range of the discharge speed of the lubricating oil is widened, and the lubricating oil can be reliably supplied to the target portion.

  Also in this configuration, as in the second configuration example, the interference between the swing holder 25 and the column portion does not cause a problem. Moreover, since it is not necessary to make the radial cross section of the column portion particularly small, the degree of freedom in design is increased. For example, when providing a plurality of oil passages, the interval between the oil passages can be widened, and the workability can be improved.

  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 or applied by those skilled in the art based on the description of the specification and well-known techniques. The invention is intended and is within the scope of seeking protection.

As described above, the following items are disclosed in this specification.
(1) A sun roller connected to the input shaft, a ring roller arranged concentrically with the sun roller on the outer peripheral side of the sun roller, connected to the output shaft, an outer peripheral surface of the sun roller, and an inner peripheral surface of the ring roller A plurality of intermediate rollers that are in rolling contact with each other, are rotatably supported, a plurality of swing holders that are provided on each of the plurality of intermediate rollers, and support the rotation shaft of the intermediate rollers, and the plurality of swing holders A friction roller type speed reducer comprising:
The swing holder is provided at both end portions of the rotation shaft, each of which has a pair of bearing holding portions formed with support holes for supporting the end portions of the rotation shaft, and the pair of bearing holding portions. A bridging portion that is connected across the outer periphery,
The bearing holding portion has an oscillating shaft outer peripheral surface centered on the oscillating shaft at a position eccentric from the rotation shaft by a length equal to or less than the radius of the intermediate roller,
The carrier has a holder support portion that rotatably supports the outer peripheral surface of the swing shaft,
A pair of the bridging portions are disposed with the rotation shaft interposed therebetween, and a friction roller type reduction gear.
According to the friction roller type speed reducer of this configuration, the pair of bearing holding portions are connected by the pair of bridging portions, so that the relative torsion of the bearing holding portion is suppressed and the support shaft is less likely to be inclined. As a result, the intermediate roller is not inclined with respect to the rotation shaft of the sun roller or the ring roller, and a problem such as an increase in rotational torque due to mutual friction does not occur. Therefore, the intermediate roller can be prevented from being tilted, and an imbalance in the surface pressure at the contact point between the sun roller, the ring roller and the intermediate roller can be prevented.
(2) The friction roller type reduction gear according to (1), further comprising a loading cam mechanism that applies a pressing force between the sun roller and the intermediate roller in accordance with a magnitude of a transmission torque.
According to the friction roller type speed reducer having this configuration, the pressing force between the rollers becomes an appropriate pressure corresponding to the transmission torque by the loading cam mechanism, and the power transmission efficiency is improved.

DESCRIPTION OF SYMBOLS 11 Input shaft 13 Output shaft 15 Sun roller 17 Ring roller 19 Intermediate roller 19B Support shaft 21 Connection part 23 Loading cam mechanism 25 Swing holder 27 Carrier 27A 1st carrier member 27B 2nd carrier member 28 Bearing holding part 69 Holder support part 71 Support Hole 73 Oscillating shaft outer peripheral surface 75A, 75B Bridging part 100 Friction roller type speed reducer

Claims (2)

Rolling contact with the sun roller connected to the input shaft, the ring roller arranged concentrically with the sun roller on the outer peripheral side of the sun roller, and connected to the output shaft, the outer peripheral surface of the sun roller and the inner peripheral surface of the ring roller And a plurality of intermediate rollers rotatably supported, a plurality of swing holders provided on each of the plurality of intermediate rollers and supporting the rotation shaft of the intermediate rollers, and the plurality of swing holders. A friction roller type speed reducer comprising a carrier,
The swing holder is provided at both end portions of the rotation shaft, each of which has a pair of bearing holding portions formed with support holes for supporting the end portions of the rotation shaft, and the pair of bearing holding portions. A bridging portion that is connected across the outer periphery,
The bearing holding portion has an oscillating shaft outer peripheral surface centered on the oscillating shaft at a position eccentric from the rotation shaft by a length equal to or less than the radius of the intermediate roller,
The carrier has a holder support portion that rotatably supports the outer peripheral surface of the swing shaft,
A pair of the bridging portions are disposed with the rotation shaft interposed therebetween, and a friction roller type reduction gear.   The friction roller type speed reducer according to claim 1, further comprising a loading cam mechanism that applies a pressing force between the sun roller and the intermediate roller in accordance with a magnitude of a transmission torque.

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