JP6485181B2 - Friction roller reducer - Google Patents

Description

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

  In order to improve the convenience of electric vehicles that have begun to spread in recent years, there is a strong demand for improving the efficiency of electric motors in order to increase the travelable distance per charge. In order to improve the efficiency of the electric motor, it is desirable to use a small electric motor that rotates at high speed and to reduce the rotation of the motor output shaft before transmitting it to the drive wheels of the vehicle. In that case, the speed reducer connected to the motor output shaft has a very high operating speed and is likely to generate vibration and noise. Therefore, in order to suppress vibration and noise during operation, it is considered to use a friction roller type speed reducer. As a conventional friction roller type speed reducer, for example, one described in Patent Document 1 is known.

  As shown in FIG. 13, a friction roller type speed reducer 200 described in Patent Document 1 includes an input shaft 111, an output shaft 113, a sun roller 117, a ring roller 119, a plurality of intermediate rollers 121, and a loading. The cam mechanism 123 includes a connecting portion 133 that connects the ring roller 119 and the output shaft 113. The input shaft 111 is rotatably supported by a rolling bearing 127 provided in the housing 125 and a rolling bearing 131 provided in the bearing hole portion 129 of the output shaft 113. The output shaft 113 is rotatably supported by a rolling bearing 135 provided on the inner peripheral portion of the housing 125.

  The sun roller 117 has a pair of sun roller elements 137A and 137B divided in the axial direction. The sun roller element 137A is arranged so as to be capable of axial movement and relative rotation with respect to the input shaft 111. The sun roller elements 137 </ b> A and 137 </ b> B have inclined surfaces whose outer diameters increase from the front end surfaces facing each other toward the outside in the axial direction, and these inclined surfaces serve as rolling contact surfaces with the intermediate roller 19. That is, the outer diameter of the rolling contact surface of the sun roller 117 as a whole is small at the intermediate portion in the axial direction and becomes larger toward both ends in the axial direction.

  The ring roller 119 is an annular roller disposed concentrically with the sun roller 117 on the outer side in the radial direction of the sun roller 117. The outer peripheral portion of the ring roller 119 is connected to the connecting portion 133 via the power transmission portion 139 and rotates integrally with the output shaft 113.

  As shown in FIG. 14, the power transmission unit 139 has a plurality of concave grooves 143 formed in the cylindrical portion 141 of the coupling portion 133 along the axial direction and a plurality of outer peripheral portions of the ring roller 119 radially outward. And a plurality of protrusions 145 formed to protrude. These protrusions 145 engage with the concave groove 143 of the cylindrical portion 141 without rattling in the circumferential direction, so that torque can be transmitted between the ring roller 119 and the connecting portion 133 (output shaft 113). It has become.

  The intermediate roller 121 shown in FIG. 13 is rotatably supported by the support shaft 147 and has a convex curved outer peripheral surface. The intermediate rollers 121 are in rolling contact with the outer peripheral surface of the sun roller 117 and the inner peripheral surface of the ring roller 119, respectively.

  The loading cam mechanism 123 is disposed at the end of the sun roller element 137A opposite to the sun roller element 137B. As shown in FIG. 15, the base end surface of the sun roller element 137A facing the cam ring 149 and the one side surface of the cam ring 149 facing the sun roller element 137A are arranged at a plurality of locations along the circumferential direction on the sun roller element 137A side. A driven cam surface 153 and a driving cam surface 155 on the cam ring 149 side are provided. Balls 157 are arranged between the cam surfaces 155 and 153, respectively. Each of the cam surfaces 153 and 155 has a shape in which the depth in the axial direction becomes gradually shallower toward both ends in the circumferential direction.

  In the loading cam mechanism 123 configured as described above, in the state where the input shaft 111 is stopped, each ball 157 has a cam surface 153, as shown in FIG. It is located at the deepest part of 155. When the input shaft 111 is driven to rotate, the balls 157 move to shallow portions of the cam surfaces 153 and 155 as shown in FIG. As a result, the distance Lc between the sun roller element 137A and the cam ring 149 increases, and the sun roller element 137A is driven to rotate while being pressed toward the sun roller element 137B.

  That is, in a state where no rotational torque is input to the input shaft 111, as shown in FIG. 17A, the balls 157 of the loading cam mechanism 123 are located on the bottoms of the cam surfaces 153 and 155 or near the bottoms. Exists. 17B, the sun roller element 137A is displaced in the axial direction by the axial thrust generated by the loading cam mechanism 123 during operation of the friction roller type speed reducer shown in FIG. Then, the intermediate roller 121 and the ring roller 119 are also displaced in the axial direction, and exist between the input shaft 111 and the output shaft 113 including the outer peripheral surface of the sun roller 117 and the outer peripheral surface of each intermediate roller 121. Contact surface pressure rises at a plurality of rolling contact portions provided for power transmission.

Japanese Patent No. 4948968

  However, in the friction roller type speed reducer 200 disclosed in Patent Document 1, the loading cam mechanism 123 is disposed on the sun roller 117 side. Therefore, the rotation radius from the rotation center of the input shaft 111 shown in FIG. 13 to the rolling contact region (contact ellipse) between the outer peripheral surface of the sun roller elements 137A and 137B and the outer peripheral surface of the intermediate roller 121 is short, and the contact at the rolling contact portion The peripheral speed difference increases in accordance with the difference between the radial distance at both ends in the axial direction of the region and the radial distance at the center. As a result, slipping occurred at the rolling contact portion, and the power transmission efficiency of the friction roller type reduction gear was reduced.

  On the other hand, although not shown, there is known a friction roller type speed reducer in which a loading cam mechanism is provided on the ring roller side. In this speed reducer, by providing the loading cam mechanism on the ring roller side, the radius of rotation from the rotation center of the input shaft to the rolling contact portions of the inner peripheral surface of the ring roller and the outer peripheral surface of each intermediate roller can be increased. . Thereby, the radial distance difference between the axial both ends of the contact area in the rolling contact portion and the central portion can be reduced with respect to the radial distance, and the generated peripheral speed difference can be suppressed to be small.

  However, in the friction roller type speed reducer in which the loading cam mechanism is arranged on the ring roller side, the power transmission between the ring roller and the connecting portion (output shaft) is formed on the outer peripheral surface of the ring roller 119 as shown in FIG. This is performed by engaging the projection 145 with the concave groove 143 formed in the cylindrical portion 141 of the connecting portion 133. Therefore, there is a problem that wear due to sliding occurs in the engaging portion. That is, the protrusion 145 of the ring roller 119 and the concave groove 143 of the cylindrical portion 141 are engaged with each other with an axial movement allowance therebetween. When an axial thrust is generated in the ring roller 119, the power transmission load in the rotational direction and the axial thrust simultaneously act on the protrusion 145 and the groove 143, and the protrusion 145 and the groove 143 slide and wear. .

  Further, the axial thrust that causes the abrasion of the protrusion 145 and the concave groove 143 is generated by misalignment caused by an assembly error. Further, since the rolling contact portions between the ring roller 119 and the intermediate roller 121 are concentrated on a part of the circumferential direction of the ring roller 119, the rotation shafts of the ring roller 119 and the intermediate roller 121 are likely to have a relative inclination (skew). An axial load is also generated by the inclination of the shaft center.

  The present invention has been made in view of the above matters, and its purpose is to reduce friction loss at each rolling contact portion and to prevent wear due to sliding at the engaging portion between the connecting portion of the output shaft and the ring roller. 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 disposed concentrically with the input shaft, a ring roller disposed concentrically with the sun roller on an outer peripheral side of the sun roller, and between an outer peripheral surface of the sun roller and an inner peripheral surface of the ring roller, A plurality of intermediate rollers that are rotatably supported around a rotation axis parallel to the input shaft and are in rolling contact with the outer peripheral surface of the sun roller and the inner peripheral surface of the ring roller, and the ring roller and the output shaft are connected. A friction roller type speed reducer comprising: a connecting portion; and a loading cam mechanism for changing a contact surface pressure of a rolling contact surface of each roller,
The ring roller includes a pair of ring roller elements arranged in parallel in the axial direction of the input shaft, at least one of which is a movable ring roller element movable in the axial direction, and an inner peripheral surface of each ring roller element is The ring roller elements are inclined surfaces whose inner diameters become smaller from the opposite end surfaces facing each other toward the outer end surface opposite to the axial direction,
The coupling portion includes a base end portion connected to the output shaft, and a roller holding portion that extends from the base end portion and holds the pair of ring roller elements,
The loading cam mechanism includes a first cam groove provided at a plurality of locations along a circumferential direction of an outer end face of the movable ring roller element, and a first cam groove arranged to face the outer end face of the movable ring roller element. And a plurality of rolling elements sandwiched between the first cam groove and the second cam groove, respectively, and the first cam The groove and the second cam groove each have a shape in which the axial depth gradually changes along the circumferential direction, and becomes shallower toward the circumferential end of the cam groove,
The roller holding portion is formed with a concave groove along the axial direction on an inner peripheral portion,
Of the pair of ring roller elements and the cam ring, a friction roller type speed reducer characterized in that a protrusion engaging with the groove is formed on the outer peripheral portion of the remaining member excluding the movable ring roller element. .
(2) The connecting portion includes a first stepped portion having a peripheral surface formed concentrically with the input shaft and parallel to the axial direction at the base end portion.
The friction ring type speed reducer according to (1), wherein the cam ring has a second stepped portion formed with a peripheral surface concentrically with the ring center and fitted to the peripheral surface of the first stepped portion. Machine.

  According to the friction roller type speed reducer of the present invention, the loading cam mechanism for moving the ring roller in the axial direction is provided on the ring roller side, and the friction loss on the rolling contact surface can be reduced. In addition, between the input shaft and the output shaft without sliding the projection of the pair of ring roller elements and the cam ring on the outer peripheral portion of the member and the concave groove of the roller holding portion in the axial direction. Rotational torque can be transmitted with, and wear due to sliding between the protrusion and the groove can be prevented.

  Further, according to the friction roller type speed reducer of the present invention, the first stepped portion provided in the outer peripheral portion of the base end portion of the connecting portion and the second stepped portion provided in the cam ring are fitted, Regardless of the presence of the protrusions on the outer periphery of the cam ring, the respective axial center positions can be adjusted with high accuracy. Further, since the cam ring is fitted to the base end portion of the connecting portion and is not fitted to the roller holding portion, it is not necessary to increase the accuracy of the inner diameter of the roller holding portion. Therefore, even if the connecting part is produced by a low-cost method such as welding the roller holding part processed by plastic processing or the like and the base end part processed by cutting or the like, it is possible to reliably prevent the occurrence of axial misalignment. .

It is a figure for demonstrating embodiment of this invention, and is a partial cross section perspective view of a friction roller type reduction gear. It is a principal part expanded sectional view of the friction roller type reduction gear shown in FIG. It is a disassembled perspective view of each member accommodated in the connection part of a friction roller type reduction gear. It is a partially expanded sectional view which shows the engagement state of a connection part and a cam ring. It is a fragmentary sectional view which shows the state from which traction oil is discharged | emitted from the slit hole of a connection part. It is a disassembled perspective view of the carrier of the other structural example. It is a side view of the carrier seen from the V direction of FIG. It is the PP sectional view taken on the line of FIG. It is a partially expanded perspective view of the carrier which shows the shape of the oil supply groove | channel used as an injection port. It is a partially expanded perspective view of the carrier which shows the 1st modification of the oil supply groove | channel used as an injection port. It is a partially expanded perspective view of the carrier which shows the 2nd modification of the oil supply groove | channel used as an injection port. It is a partially expanded perspective view of the carrier which shows the 3rd modification of the oil supply groove | channel used as an injection port. It is sectional drawing of the conventional friction roller type reduction gear. It is a disassembled perspective view of a power transmission part. It is a top view of the cam ring which shows the cam surface of a loading cam mechanism. It is AA sectional drawing of FIG. 15, Comprising: It is sectional drawing which each shows the state (A) in which the loading cam mechanism is not generating the thrust, and the state (B) which is generating the thrust. It is a schematic diagram of the friction roller type reduction gear which shows the state where an intermediate roller is displaced based on the action of the loading cam mechanism, when torque is not transmitted (A) and when transmitted (B).

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Configuration of friction roller reducer>
FIG. 1 is a view for explaining an embodiment of the present invention, and is a partial cross-sectional perspective view of a friction roller type speed reducer, and FIG. 2 is an enlarged cross-sectional view of a main part of the friction roller type speed reducer. As shown in FIGS. 1 and 2, the friction roller type speed reducer 100 includes a sun roller 15, a ring roller 17, a plurality of intermediate rollers 19, a ring roller 17, and an output shaft 13 that are arranged concentrically with the input shaft 11. And a loading cam mechanism 23. The sun roller 15, the ring roller 17, the plurality of intermediate rollers 19, the connecting portion 21, and the loading cam mechanism 23 are housed in a housing 77 (see FIG. 5). The input shaft 11 and the output shaft 13 are rotatably supported on the housing 77 by a rolling bearing (not shown).

  The sun roller 15 is a solid structure roller provided at one end of the input shaft 11 shown in FIG. The sun roller 15 is formed integrally with the input shaft 11 by cutting and grinding the input shaft 11.

  The ring roller 17 is a pair of ring roller elements arranged in parallel in the axial direction, and includes a fixed ring roller element 27 and a movable ring roller element 29 movable in the axial direction. These ring roller elements 27 and 29 are arranged concentrically with the sun roller 15 on the outer peripheral side of the sun roller 15 in a state of being accommodated inside the cup-shaped connecting portion 21.

  The inner peripheral surfaces of the fixed ring roller element 27 and the movable ring roller element 29 are inclined surfaces in which the inner diameter decreases as the ring roller elements 27, 29 face each other from the opposing end face 24 toward the outer end face on the opposite side in the axial direction. It has become. Each of these inclined surfaces becomes a rolling contact surface on which the intermediate roller 19 rolls. The fixed ring roller element 27 has a plurality (three in the illustrated example) of protrusions 28 protruding in the radial direction at a plurality of locations on the outer peripheral portion.

  The plurality of intermediate rollers 19 are supported by a support shaft (spinning shaft) 31 via a needle bearing (not shown) so as to be rotatable and displaceable in the axial direction. It is arranged between the peripheral surface.

  Both ends of the support shaft 31 are supported by the carrier 33 via the roller holder 32 shown in FIG. The roller holder 32 is supported by the carrier 33 so that the intermediate roller 19 can move (swing) in the radial direction of the input shaft. The carrier 33 is fixed to a motor body (not shown) by a fastening member 35.

  The outer peripheral surface of each intermediate roller 19 is a convex curve having a single circular arc outer edge in the axial section, and is in rolling contact with the outer peripheral surface of the sun roller 15 and the inner peripheral surface of the ring roller 17.

  The connecting portion 21 is formed in a substantially disc shape and has a base end portion 37 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 37. And a cylindrical roller holding portion 39 to be held.

  A plurality of concave grooves 43 for torque transmission are formed along the axial direction in the inner peripheral portion of the roller holding portion 39. In addition, a ring groove 45 is formed on the entire circumference in the circumferential direction on the inner peripheral portion of the end portion of the roller holding portion 39 opposite to the base end portion 37. A substantially annular retaining ring 47 is fitted in the ring groove 45. The retaining ring 47 restricts the position of the fixed ring roller element 27 in the axial direction and prevents the fixed ring roller element 27 from falling off the roller holding portion 39.

  Then, the protrusion 28 of the fixed ring roller element 27 engages with the concave groove 43 of the roller holding portion 39 in a state where there is no backlash in the rotational direction, thereby enabling transmission of rotational torque. As will be described in detail later, the roller holding portion 39 is formed with a plurality of slit holes 75 penetrating in the radial direction.

  For example, the base end portion 37 of the connecting portion 21 is formed by a cutting process such as a lathe process, and the roller holding part 39 is formed by a plastic process such as press molding. After the base end portion 37 and the roller holding portion 39 are formed as a single unit, the shaft cores can be manufactured with high accuracy at low cost by joining them together. Further, the base end portion 37 and the roller holding portion 39 are joined by beam welding. As a result, it is possible to perform heat bonding with a narrow bead and in a short time, and it is possible to suppress the occurrence of misalignment by minimizing thermal distortion.

  FIG. 3 shows an exploded perspective view of each member accommodated in the connecting portion 21. Inside the roller holding portion 39 of the connecting portion 21, from the base end portion 37 side, a corrugated preload spring 67, a cam ring 49, a ball 51 as a rolling element, a movable ring roller element 29, a fixed ring roller element 27, The retaining ring 47 is inserted in this order and assembled to the roller holding portion 39.

<Loading cam mechanism>
Next, the loading cam mechanism will be described.
The movable ring roller element 29 shown in FIG. 2, the cam ring 49 disposed so as to face only the outer end face side of the movable ring roller element 29, and the balls 51 that are rolling elements constitute the loading cam mechanism 23. The loading cam mechanism 23 changes the contact surface pressure of each rolling contact surface of the sun roller 15, the ring roller 17, and the intermediate roller 19.

  As shown in FIG. 3, a plurality of first cam grooves 53 (three places at equal intervals in the circumferential direction in the illustrated example) are formed on the outer end surface of the movable ring roller element 29 along the circumferential direction. Yes. The cam ring 49 is formed with a plurality of second cam grooves 55 (three places at equal intervals in the circumferential direction in the illustrated example) at circumferential positions corresponding to the first cam grooves 53. The balls 51 are sandwiched between the first cam groove 53 and the second cam groove 55, respectively.

  As shown in FIGS. 15, 16A, and 16B, the first cam groove 53 and the second cam groove 55 each have an axial groove depth that gradually changes along the circumferential direction. The groove depth in the axial direction is deepest at the center in the circumferential direction, and gradually becomes shallower toward the circumferential ends of the cam grooves 53 and 55.

  The cam ring 49 has a plurality of (three in the illustrated example) protrusions 61 protruding radially outward from the outer peripheral portion thereof. The protrusion 61 of the cam ring 49 and the protrusion 28 of the fixed ring roller element 27 engage with the concave groove 43 of the roller holding portion 39, respectively.

  The loading cam mechanism 23 of this configuration includes a sun roller element 137A having a driven cam surface 153, a cam ring 149 having a driving cam surface 155, and a plurality of cam surfaces 153 and 155 disposed between the cam surfaces 153 and 155, respectively. The basic operation principle is the same as that of the conventional loading mechanism configured to include the ball 157. However, the difference is that the loading cam mechanism is disposed on the ring roller side.

<Engagement of connecting portion with cam ring and ring roller>
FIG. 4 is a partially enlarged cross-sectional view showing an engaged state between the connecting portion 21 and the cam ring 49. The cam ring 49 is formed with a notch 63 formed on the outer end surface on the output shaft side, with a part of the outer diameter side notched in an annular shape, and a preload spring 67 is attached to the notch 63. A first stepped portion 41 having an inner peripheral surface parallel to the input shaft 11 is formed on the inner side surface of the base end portion 37. Further, the outer end surface of the cam ring 49 is concentric with the center of the ring, and has a second stepped surface having an outer peripheral surface that fits along the axial direction with the first stepped portion 41 of the base end portion 37 of the connecting portion 21. The portion 65 is formed to protrude in the axial direction.

  The cam ring 49 and the connecting portion 21 are aligned with each other with high accuracy by fitting the first stepped portion 41 and the second stepped portion 65 in-slot. As a result, the axial center position of the movable ring roller element 29 is also exactly in agreement with the cam ring 49 and the connecting portion 21 via the cam ring 49.

  Further, the fixed ring roller element 27 shown in FIG. 2 is positioned in the radial direction by the intermediate roller 19. Since the intermediate roller 19 is positioned in the radial direction by the sun roller 15 concentric with the input shaft 11 and the input shaft 11 and the output shaft 13 are disposed concentrically, the sun roller 15, the ring roller 17, and the cam ring 49 are Axes are accurately aligned.

  If there are protrusions on the outer peripheral surface of the cam ring 49, it is difficult to provide a cylindrical surface for fitting the spigot on the outer peripheral surface of the cam ring 49. Thus, as in this configuration, by providing the second stepped portion 65 on the side surface of the cam ring 49, positioning and power transmission can be carried on different parts of the cam ring 49, and both functions are not hindered from each other. It will be possible to demonstrate.

  Further, the cam ring 49 is formed with an annular space 71 between the notch portion 63 and the inner surface 69 of the base end portion 37 of the connecting portion 21. A preload spring 67 is disposed in the annular space 71, and the cam ring 49 is biased by the preload spring 67 to the side opposite to the base end portion 37 in the axial direction. In this state, the annular second stepped portion 65 is fitted into the annular first stepped portion 41 formed at the base end portion 37.

  The engagement margin La (the maximum length that can be engaged) between the first stepped portion 41 and the second stepped portion 65 is greater than the elastic deformation margin Lb of the preload spring 67 (the maximum length that the preload spring 67 can retract). It is set long. Therefore, even if the cam ring 49 is pressed to the opposite side (movable ring roller element 29 side) from the base end portion 37 by the elastic force of the preload spring 67, the first stepped portion 41 and the second stepped portion 65 The fitting is not released.

  By fitting the first stepped portion 41 and the second stepped portion 65, the preload spring 67 can be compressed in a state in which the coaxiality between the connecting portion 21 and the cam ring 49 is ensured. Therefore, when the cam ring 49 is assembled to the base end portion 37, the preload spring 67 can be prevented from coming off between the cam ring 49 and the base end portion 37, and the assemblability of assembling the cam ring 49 and the preload spring 67 to the connecting portion 21 is improved. it can.

<Effects of friction roller reducer>
Next, the operation of the friction roller type speed reducer 100 including the loading cam mechanism 23 having the above configuration will be described.
In the state where the input shaft 11 shown in FIG. 2 is stopped, each ball 51 is located at the deepest part of each cam groove, as shown in FIG. In this state, the cam ring 49 is pressed toward the movable ring roller element 29 by the elastic force of the preload spring 67.

  Here, when the input shaft 11 is rotationally driven, each ball 51 moves to a shallow part of each cam groove as shown in FIG. 16B, and the movable ring roller element 29 is fixed to the fixed ring roller element. Press toward 27.

  At this time, since the reaction force of the pressing force acts on the cam ring 49, the cam ring 49 moves in the direction opposite to the pressing direction while crushing the preload spring 67. Then, the outer side surface 73 of the second stepped portion 65 comes into contact with the inner side surface 69 of the base end portion 37, and the axial position of the cam ring 49 is restricted. The elastic deformation margin Lb of the preload spring 67 is small compared to the amount of movement of the movable ring roller element 29, and the preload spring 67 is elastically deformed and slides in the low torque region. The contact surface pressure of the part is low. Therefore, there is almost no influence of wear due to sliding with the concave groove 43.

  The distance between the fixed ring roller element 27 and the movable ring roller element 29 is reduced by the axial thrust generated by the loading cam mechanism 23 shown in FIG. Then, the contact surface pressure at the rolling contact portion between the inner peripheral surface of the ring roller 17 constituted by the fixed ring roller element 27 and the movable ring roller element 29 and the outer peripheral surface of each intermediate roller 19 increases. As the contact surface pressure increases, the contact surface pressure of the rolling contact portion between the outer peripheral surface of each intermediate roller 19 and the outer peripheral surface of the sun roller 15 also increases. As a result, the contact surface pressure of the plurality of rolling contact portions existing between the input shaft 11 and the output shaft 13 increases as the torque to be transmitted between the input shaft 11 and the output shaft 13 increases.

  In a state where the input shaft 11 is rotationally driven, the rotation of the input shaft 11 is transmitted from the sun roller 15 to each intermediate roller 19, and each intermediate roller 19 rotates around the support shaft 31. The ring roller 17 is rotated by the rotation of each intermediate roller 19, and the projection 28 of the fixed ring roller element 27 is engaged with the concave groove 43 of the roller holding portion 39, whereby the output shaft connected to the roller holding portion 39. 13 rotates.

  At this time, the contact surface pressure of each rolling contact portion becomes appropriate according to the magnitude of the torque to be transmitted between the input shaft 11 and the output shaft 13, and excessive slippage occurs at each rolling contact portion. Further, an increase in rolling resistance due to an excessive contact surface pressure at each rolling contact portion is prevented.

  Further, while torque is being transmitted between the input shaft 11 and the output shaft 13, the fixed ring roller element 27 abuts against the retaining ring 47 and its axial position is restricted, and the cam ring 49 is in the second stage. The axial position is regulated by the contact between the outer surface 73 of the attaching portion 65 and the inner surface 69 of the base end portion 37. That is, the fixed ring roller element 27 having the protrusions 28 and the cam ring 49 having the protrusions 61 are engaged with the concave grooves 43 to transmit rotational power and are not substantially displaced in the axial direction.

  Therefore, there is no sliding at the engaging portion between the protrusion 28 of the fixed ring roller element 27 and the protrusion 61 of the cam ring 49 and the concave groove 43, and it is possible to prevent wear at the engaging portion. Further, since the radial distance from the center of rotation of the ring roller 17 to the rolling contact portion between each inner circumferential surface of the ring roller 17 and the outer circumferential surface of each intermediate roller 19 is long, both ends of the rolling contact region (contact ellipse) are provided. The circumferential speed difference can be kept small. As a result, the friction loss at the rolling contact portion is reduced and torque can be transmitted with high efficiency.

<Traction oil circulation>
In the friction roller type speed reducer 100 of this configuration, traction oil is circulated inside the transmission. The sun roller 15, the ring roller 17, the plurality of intermediate rollers 19, and the loading cam mechanism 23 are accommodated inside the connecting portion 21, and the supplied traction oil may stay inside the connecting portion 21. In that case, lubrication of each mechanism part arrange | positioned outside the connection part 21 becomes inadequate, it leads also to the stirring resistance of traction oil increasing, and torque transmission efficiency falling.

  Accordingly, as shown in FIG. 5, the friction roller type speed reducer 100 of this configuration has a plurality of slit holes 75 penetrating in the radial direction in the roller holding portion 39 of the connecting portion 21. The traction oil supplied and lubricated to the rolling contact portion is discharged radially outward through the plurality of slit holes 75. The outer side of the friction roller type speed reducer 100 is covered with a housing 77, and the traction oil discharged from the roller holding portion 39 is collected at a predetermined position in the housing 77 and is circulated and supplied to the rolling contact portion again. Is done.

  For this reason, torque transmission efficiency is not reduced by the stirring resistance of the traction oil during the reduction gear operation. Further, the formation of the slit hole 75 has an effect of reducing the weight of the roller holding part 39 and reducing the inertial resistance at the initial stage of operation, and an effect of improving the maintainability by making the inside of the roller holding part 39 visible through the slit hole 75. can get.

  The connecting portion 21 is composed of two parts, a base end portion 37 and a roller holding portion 39. The base end portion 37 and the roller holding portion 39 are individually manufactured and then joined to each other. For this reason, even if the roller holding portion 39 is distorted by welding or the like, the first stepped portion 41 that is fitted into the cam ring 49 with the inlay is provided at the base end portion 37, so that it is not affected by the distortion. The plurality of slit holes 75 formed in the roller holding portion 39 can be easily provided by hole processing such as press molding before joining to the base end portion 37. Even if the inner diameter accuracy of the roller holding portion 39 is reduced by this hole processing, this does not affect the axial center position. By the above joining, the connecting portion 21 can be manufactured at a low cost.

  Furthermore, since the movable ring roller element 29 and the cam ring 49 are not used in the portion where the outer diameter surfaces thereof are fitted with the inlay, the inner diameter accuracy of the roller holding portion 39 of the connecting portion 21 does not need to be particularly increased. This can also reduce the manufacturing cost.

  The fixed ring roller element 27 and the movable ring roller element 29 of this configuration have a structure in which the position in the axial direction is determined by the sun roller 15 via a plurality of intermediate rollers 19. Alternatively, the fixed ring roller element 27 and the movable ring roller element 29 can be positioned with reference to the output shaft 13, that is, the connecting portion 21.

  In that case, an inlay fitting portion that is aligned by fitting the concave portion and the convex portion between the movable ring roller element 29 and the cam ring 49 and between the fixed ring roller element 27 and the connecting portion 21 is provided. Each may be provided. According to this configuration, only the ring groove 45 of the roller holding portion 39 and the inner diameter surface on the tip side of the ring groove 45 need to be processed with high accuracy, and the inner diameter processing of the connecting portion 21 can be minimized. Can do.

<Other configurations>
In the friction roller type speed reducer 100 of this configuration, only one side of a pair of ring roller elements is a movable ring roller element. However, both ring roller elements are movable ring roller elements, and a loading cam mechanism is used for both ring roller elements. It is good also as a structure provided with respect to each. In that case, the cam ring of each loading cam mechanism is provided with a protrusion that engages with the concave groove 43 formed in the roller holding portion 39 of the connecting portion 21, and this protrusion allows the connecting portion 21, the ring roller 17, and the middle. Rotational torque is transmitted to and from the roller 19. That is, since the pair of ring roller elements are both movable ring roller elements, the above-described protrusion 28 is not provided. According to this configuration, both the ring roller elements can move in the axial direction without sliding with the concave groove 43 by the rotational torque. Therefore, the movable ring rollers are equally displaced in the axial direction due to the change in the transmission torque, and the axial movement of the intermediate roller can be suppressed. For this reason, higher torque transmission efficiency can be obtained.

<Other configuration examples of traction oil supply oil passage>
Next, another configuration example of the traction oil supply oil path in the friction roller type reduction gear 100 will be described. In this configuration, a traction oil supply passage for supplying traction oil to the sun roller 15 and the ring roller 17 is formed in the carrier 33A.

  6 is an exploded perspective view of the carrier 33A, FIG. 7 is a side view of the carrier 33A viewed from the direction V in FIG. 6, and FIG. 8 is a cross-sectional view taken along the line P-P in FIG. In addition, about the member which is the same as the member mentioned above or respond | corresponds, the description is abbreviate | omitted or simplified by giving the same code | symbol.

  As shown in FIG. 6, the carrier 33 </ b> A includes a first carrier member 81 and a second carrier member 83. The first carrier member 81 and the second carrier member 83 include a ring-shaped bottom portion 85 and pillar portions 87 erected 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 each.

  The column portions 87 of the first carrier member 81 and the second carrier member 83 are penetrated by insertion holes 89 and 91 along the axial direction. Bolts (not shown) are inserted through the insertion holes 89 and 91. The bolts inserted into the insertion holes 89 and 91 fix the carrier 33A to a motor body (not shown) in a state where the corresponding tips of the column portions 87 are in contact with each other.

  As shown in FIG. 7, a swing holder 32 </ b> A that supports the intermediate roller 19 is disposed between the column portions 87 arranged in the circumferential direction. As shown in FIG. 8, one bearing portion 93 of the swing holder 32 </ b> A is rotatably inserted into a shaft hole 97 formed in the bottom portion 85 of the first carrier member 81, and the other bearing portion 95 is a second bearing portion 95. The carrier member 83 is rotatably inserted into a shaft hole 99 formed in the bottom portion 85 of the carrier member 83.

  In each of the column portions 87 of the first carrier member 81 and the second carrier member 83, the abutting positions of the column portions 87 coincide with the contact point between the sun roller 15 and the intermediate roller 19 in the axial direction.

  The friction roller type speed reducer 100 of this modification has a loading cam mechanism on the ring roller 17 side. The ring roller 17 is composed of a pair of ring roller elements 27 and 29, and there are two contact points with the intermediate roller 19. The sun roller 15 is a single part having no loading cam mechanism, and the contact point with the intermediate roller 19 is one point.

  Traction oil is supplied to these contact points through oil passages formed in the first carrier member 81 and the second carrier member 83. A first sun roller-side oil passage 101 and a first ring roller-side oil passage 102 are formed in the pillar portion 87 of the first carrier member 81 so as to penetrate each of them along the axial direction.

  The column part 87 of the second carrier member 83 has a second sun roller side oil passage 103 communicating with the first sun roller side oil passage 101 and a second ring roller side oil passage 104 communicating with the first ring roller side oil passage 102. Is formed.

  As shown in FIG. 9, at least one of the first carrier member 81 and the second carrier member 83 is formed with oil supply grooves 105A and 105B at the tip end of the column portion 87 (in this configuration, as an example, the second carrier Member 83). The oil supply grooves 105A and 105B are formed toward the contact point between the sun roller 15 and the intermediate roller 19, and the column portion 87 of the first carrier member 81 and the column portion 87 of the second carrier member 83 are joined together. An oil passage for traction oil is formed.

  Further, as shown in FIG. 8, communication holes 106A and 106B are connected to the first ring roller side oil passage 102 and the second ring roller side oil passage 104, respectively. The communication hole 106 </ b> A is formed from the first ring roller side oil passage 102 of the column part 87 toward the traction surface of the movable ring roller element 29. The communication hole 106 </ b> B is formed from the second ring roller side oil passage 104 of the column portion 87 toward the traction surface of the fixed ring roller element 27.

  Traction oil from a traction oil supply unit (not shown) is supplied from the bottom 85 side to the first sun roller side oil passage 101 and the first ring roller side oil passage 102.

  The traction oil supplied to the first sun roller side oil passage 101 and the second sun roller side oil passage 103 is injected from the oil supply grooves 105A and 105B as shown in FIG. That is, the oil is injected from the traction oil injection port at the tip of the oil supply groove 105 </ b> A to the contact point Q <b> 1 between the sun roller 15 and the intermediate roller 19. The oil is injected from the traction oil injection port at the tip of the oil supply groove 105B to the contact point Q2. Similarly, traction oil is jetted from the oil supply grooves 105A and 105B of the other column portions 87 toward the contact points Q1, Q2, and Q3.

  The traction oil supplied to the first ring roller side oil passage 102 and the second ring roller side oil passage 104 is sprayed to the ring roller 17 through the communication holes 106A and 106B. That is, traction oil is injected from the traction oil injection port at the tip of the communication hole 106A to the traction surface of the movable ring roller element 29, and from the traction oil injection port at the tip of the communication hole 106B to the traction surface of the fixed ring roller element 27. Traction oil is injected.

  The oil supply grooves 105 </ b> A and 105 </ b> B are provided at the same axial position as the contact point between the sun roller 15 and the intermediate roller 19. The communication holes 106A and 106B are provided at the same axial positions as the contact points of the ring roller elements 27 and 29 with the intermediate roller 19, respectively. Thereby, the traction oil from each traction oil discharge port can be efficiently supplied to the said contact point, and it can contribute to reduction of wear and improvement of cooling performance. According to the said structure, the process of the injection port which supplies traction oil to the sun roller side becomes easy, and the diameter of an injection port can be set to arbitrary diameters.

  By the way, there are various kinds of layouts of the injection ports. For example, in the planetary roller speed reducer traction oil supply method described in JP2013-104514A, the injection port is disposed toward the contact point between the sun roller and the intermediate roller. In this jet port layout, the oil passage for supplying the traction oil to the sun roller side is composed of a through-hole drilled from the outer diameter side to the inner diameter side of the carrier. An injection port is formed on the carrier inner diameter side of the through hole, and a stopper plug is press-fitted on the carrier outer diameter side. The reason why the oil passage is configured in this way is that it is difficult to drill holes from the inner diameter side of the carrier due to tool interference. However, the configuration of the oil passage in the above publication has the following problems.

  First, since it is necessary to process the through hole from the carrier outer diameter side toward the inner diameter side, the processing tool is long and it is difficult to process the small diameter hole. For this reason, when it is desired to make the injection port narrower due to the injection speed and the injection amount, it is necessary to separately add an adjustment throttle or the like to the hole base. In addition, a stop plug is required for the through hole, which increases the number of parts and an assembly process of the stop plug. Further, the through hole from the carrier outer diameter side toward the inner diameter side may restrict the direction of the injection port in order to avoid interference with other oil passages and mounting holes.

  In that respect, in the friction roller type speed reducer 100 of this configuration, an injection port that supplies traction oil toward the vicinity of the contact point between the intermediate roller 19 and the sun roller 15 is provided at the tip of the column portion 87. This injection port is configured by a groove-like oil passage formed on the tip surface of the column portion 87.

  With such a structure, as described above, the injection port can be easily processed, and interference with other oil passages and mounting holes can be easily avoided. Therefore, the degree of freedom in designing the injection port is improved, and the injection port can be easily provided in an arbitrary direction. Further, drilling from the carrier outer diameter side to a certain depth is relatively easy, and the injection port for supplying traction oil to the ring roller side can be provided at an arbitrary position.

  Furthermore, since the friction roller type speed reducer 100 has a loading cam mechanism on the ring roller side, the contact point between the sun roller and the intermediate roller is one. On the other hand, in the speed reducer of the above publication, since the loading cam mechanism is on the sun roller side, the sun roller is composed of a pair of sun roller elements. Therefore, there are two contact points between the sun roller and the intermediate roller. When the structure of the injection port of the friction roller type speed reducer 100 is applied to such a structure, two or more boundary surfaces are required, the carrier needs to be divided into three or more, an increase in the number of parts, a decrease in carrier rigidity, Moreover, it becomes a factor of a precision fall.

  Further, in this configuration, since the loading cam mechanism is provided on the ring roller 17 side, the amount of oil supplied on the ring roller 17 side is larger than that on the sun roller 15 side. Therefore, the diameter of the injection port on the sun roller 15 side is made smaller than the diameter of the injection port on the ring roller 17 side. In that case, in the case of the above publication, since the injection port is provided by the through hole penetrating from the carrier outer diameter side, it is difficult to reduce the diameter of the injection port. On the other hand, in this configuration, since the injection port on the sun roller side can be formed by groove processing, there are few restrictions on the groove size and shape.

  FIG. 9 is a partially enlarged perspective view of the carrier showing the shape of the oil supply grooves 105A and 105B serving as the injection ports. The oil supply grooves 105A and 105B are formed linearly from the second sun roller side oil passage 103 to the carrier inner diameter side. In the illustrated example, the grooves are formed linearly, but may be curved grooves. Further, the width (groove width) of the oil passage can be narrowed or widened in the middle.

<Modification of oiling groove>
Next, a modified example of the oil supply groove serving as the injection port will be described.
FIG. 10 is a partially enlarged perspective view of the carrier showing a first modified example of an oil supply groove serving as an injection port.
The oil supply grooves 105 </ b> A and 105 </ b> B of this modification have a thick groove portion 108 connected to the second sun roller side oil passage 103. The thick groove portion 108 stores the traction oil supplied from the second sun roller side oil passage 103 and jets the traction oil vigorously from the oil supply grooves 105A and 105B having a narrower groove width than the thick groove portion 108.

  According to the above configuration, the amount of traction oil supplied and the injection speed can be changed by adjusting the ratio between the groove width of the thick groove portion 108 and the groove width of the oil supply grooves 105A and 105B.

FIG. 11 is a partially enlarged perspective view of the carrier showing a second modification of the oil supply groove serving as the injection port.
In the oil supply grooves 107A and 107B of this modification, the groove depth along the second sun roller side oil passage 103 of the column portion 87 is made deeper toward the second sun roller side oil passage 103 side and shallower toward the carrier inner diameter side. ing. As a result, the groove cross-sectional areas of the oil supply grooves 107A and 107B become smaller toward the carrier inner diameter side, and traction oil is jetted vigorously.

  According to the said structure, the supply oil path and injection speed of traction oil can be changed by adjusting the groove depth of oil supply groove | channel 107A, 107B.

FIG. 12 is a partially enlarged perspective view of the carrier showing a third modification of the oil supply groove serving as the injection port.
The oil supply grooves 105 </ b> A and 105 </ b> B of this modification communicate with the oil chamber 109 connected to the second sun roller side oil passage 103. That is, the oil supply grooves 105 </ b> A and 105 </ b> B are arranged at the edge of the oil chamber 109 as injection ports.

  According to the above configuration, by adjusting the groove width of the oil supply grooves 105A and 105B and the size of the oil chamber 109, the amount of traction oil supplied and the injection speed can be changed.

  In addition, when blanks such as the above-described thick groove portion 108 and oil chamber 109 are formed on a carrier by plastic working such as forging, it is also possible to previously form oil supply grooves 105A and 105B that become oil passages by a forging process. It is. Conversely, especially for the thick part of the oil passage, the part of the thick oil passage may be formed in advance by forging, and only the injection port may be provided by machining.

  As described above, the present invention is not limited to the above-described embodiments, but can be modified by those skilled in the art based on combinations of the configurations of the embodiments, descriptions in the specification, and well-known techniques. Application is also within the scope of the present invention and is within the scope of protection.

  The friction roller type speed reducer 100 of this configuration has quietness and power transmission efficiency by connecting the input shaft 11 to the output shaft of the electric motor for driving the vehicle and connecting the output shaft 13 to the drive device for the electric vehicle. It is possible to construct a high-quality electric vehicle that is high and wears the reduction gears little.

DESCRIPTION OF SYMBOLS 11 Input shaft 13 Output shaft 15 Sun roller 17 Ring roller 21 Connecting part 23 Loading cam mechanism 24 Opposite side end surface 27 Fixed ring roller element 28, 61 Protrusion 29 Movable ring roller element 31 Support shaft (spinning shaft)
37 Base end portion 39 Roller holding portion 41 First stepped portion 43 Concave groove 49 Cam ring 51 Ball (rolling element)
53 1st cam groove 55 2nd cam groove 65 2nd stepped part 100 Friction roller type reduction gear

Claims (2)

A sun roller disposed concentrically with the input shaft; a ring roller disposed concentrically with the sun roller on an outer peripheral side of the sun roller; and the input shaft between an outer peripheral surface of the sun roller and an inner peripheral surface of the ring roller. A plurality of intermediate rollers that are rotatably supported around a rotation axis parallel to the outer periphery of the sun roller and that are in rolling contact with the outer peripheral surface of the sun roller and the inner peripheral surface of the ring roller, and a connecting portion that connects the ring roller and the output shaft. A friction roller type speed reducer comprising a loading cam mechanism for changing the contact surface pressure of the rolling contact surface of each roller,
The ring roller includes a pair of ring roller elements arranged in parallel in the axial direction of the input shaft, at least one of which is a movable ring roller element movable in the axial direction, and an inner peripheral surface of each ring roller element is The ring roller elements are inclined surfaces whose inner diameters become smaller from the opposite end surfaces facing each other toward the outer end surface opposite to the axial direction,
The coupling portion includes a base end portion connected to the output shaft, and a roller holding portion that extends from the base end portion and holds the pair of ring roller elements,
The loading cam mechanism includes a first cam groove provided at a plurality of locations along a circumferential direction of an outer end face of the movable ring roller element, and a first cam groove arranged to face the outer end face of the movable ring roller element. And a plurality of rolling elements sandwiched between the first cam groove and the second cam groove, respectively, and the first cam The groove and the second cam groove each have a shape in which the axial depth gradually changes along the circumferential direction, and becomes shallower toward the circumferential end of the cam groove,
The roller holding portion is formed with a concave groove along the axial direction on an inner peripheral portion,
Of the pair of ring roller elements and the cam ring, a friction roller type speed reducer characterized in that a protrusion engaging with the groove is formed on the outer peripheral portion of the remaining member excluding the movable ring roller element. . The connecting portion has a first stepped portion having a peripheral surface formed concentrically with the input shaft and parallel to the axial direction at the base end portion,
2. The friction roller type speed reducer according to claim 1, wherein the cam ring has a second stepped portion that is concentric with the center of the ring and has a peripheral surface that is fitted to the peripheral surface of the first stepped portion. Machine.

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