JP2016114175A - Friction roller type speed reducer - Google Patents

Abstract

Provided is a friction roller type speed reducer that can be reduced in size and weight while maintaining the mechanical strength of a swinging holder, and that can suppress a change in the support position of an intermediate roller to be small and prevent a decrease in power transmission efficiency. A friction roller type speed reducer includes a plurality of swing holders 32 that support an intermediate roller 19 and a carrier 33 that pivotally supports the swing holder 32 so as to swing about a swing shaft 73 parallel to the rotation axis. Is provided. In the carrier 33, a swing shaft 73 is disposed at a circumferential position different from the rotation shaft in the circumferential direction around the sun roller 15 in a plane perpendicular to the axial direction of the sun roller 15, and is supported by the swing holder 32. When a straight line that is parallel to the tangent L0 at the contact point Pc1 where the intermediate roller 19 and the sun roller 15 are in rolling contact with each other and passes through the rotation axis of the intermediate roller 19 is a virtual straight line L1, the side closer to the sun roller 15 than the virtual straight line L1. The swing shaft 73 is disposed in the annular space. [Selection] Figure 9

Description

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

In a conventional drive device for an electric vehicle, in order to reduce the size and weight of the device, a small motor that rotates at high speed, a friction roller type speed reducer that decelerates the number of rotations of the motor and transmits it with drive wheels, Are used in combination. The friction roller type reduction gear includes an input shaft and an output shaft, and a sun roller, a ring roller, and a plurality of intermediate rollers that constitute a speed reduction mechanism (see, for example, Patent Documents 1 and 2).
The plurality of intermediate rollers are respectively rotatably supported by a swing holder having a pair of arm portions. The swing holder on which each intermediate roller is supported is provided with a swing shaft, and this swing shaft is swingably supported by the carrier on the fixed side. Thus, the intermediate roller supported by the swing holder is supported so as to be able to protrude and retract outward in the radial direction of the carrier.

JP 2014-173647 A JP 2013-108575 A

During the operation of the friction roller type speed reducer configured as described above, a load for torque transmission is applied between the intermediate roller and the sun roller and between the intermediate roller and the ring roller. The load for torque transmission balances the load and the reaction force by the reaction force acting on the swinging holder supported by the carrier.
However, depending on operating conditions, a large reaction force may be applied to the arm portion of the swing holder. Therefore, it is desirable to increase the rigidity of the arm portion to ensure the strength, but there is a problem that it is difficult to reduce the size and weight of the speed reducer.
Further, when the vehicle suddenly accelerates or decelerates, the power input to the decelerator changes abruptly. In that case, the support position of the intermediate roller is elastically displaced, and the reduction ratio changes instantaneously, which may affect the vehicle motion characteristics. Further, when the plurality of intermediate rollers cause different amounts of displacement, there is a difference between the support positions of the intermediate rollers, causing slippage between the rollers. In that case, power transmission efficiency will fall.

  The present invention has been made in view of the above matters, and can be reduced in size and weight while maintaining the mechanical strength of the swinging holder, and the amount of change in the support position of the intermediate roller can be kept small, resulting in a decrease in power transmission efficiency. It is an object of the present invention to provide a friction roller type speed reducer that can prevent the above.

The present invention has the following configuration.
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 an annular space 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,
A plurality of swing holders for rotatably supporting both end portions of the rotation shafts of the plurality of intermediate rollers;
A carrier that pivotally supports the swing holder so that it can swing around a swing axis parallel to the rotation axis;
With
The carrier has a swing shaft disposed at a circumferential position different from the rotation shaft in a circumferential direction around the sun roller in a plane perpendicular to the axial direction of the sun roller, and is supported by the swing holder. When the straight line that is parallel to the tangent at the contact point where the intermediate roller and the sun roller are in rolling contact with each other and that passes through the rotation axis of the intermediate roller is a virtual straight line, the sun roller side from the virtual straight line A friction roller type speed reducer characterized in that the rocking shaft is disposed in the annular space.

  According to the present invention, the friction roller type speed reducer can be reduced in size and weight while maintaining the mechanical strength of the swing holder. In addition, the amount of change in the support position of the intermediate roller can be suppressed to be small, and the reduction in power transmission efficiency can be prevented.

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 top view of the cam ring 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 thrust and a state (B) in which thrust is generated. It is a perspective view of the rocking | holding holder which supports an intermediate | middle roller. It is the partial cross section perspective view which cut | disconnected the carrier by the surface containing the central axis of a rocking | fluctuation axis | shaft. It is the partial cross section perspective view which cut | disconnected the rocking | fluctuation holder by the surface containing the central axis of a support shaft. It is a perspective view of the carrier and intermediate | middle roller seen from the V1 direction of the friction roller type reduction gear of FIG. It is the principal part top view seen from the V1 direction of the friction roller type reduction gear of FIG. It is explanatory drawing which shows the force which acts on one rocking | fluctuation holder shown in FIG. 9, and an intermediate | middle roller. It is explanatory drawing which shows the torque transmission force which acts on an arm part, and its component force. It is explanatory drawing which shows the force which acts on one rocking | fluctuation holder shown in FIG. 9, and an intermediate | middle roller. It is explanatory drawing which shows the torque transmission force which acts on an arm part, and its component force. It is explanatory drawing which shows the inclination | tilt angle of the arm part of a rocking | fluctuation holder.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Configuration of friction roller reducer>
First, the overall configuration of the friction roller type speed reducer will be described.
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. 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 is a solid structure roller integrally formed with the input shaft 11 at one end of the input shaft 11 shown in FIG. 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 outer peripheral surface 15a of the sun roller 15 is not limited to a curved surface, but may be a pair of inclined annular surfaces having a linear cross section whose diameter decreases from the both axial ends toward the axial center.

  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 disposed 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 27a and 29a of the fixed ring roller element 27 and the movable ring roller element 29 are directed from the opposite end faces 24 and 24 where the ring roller elements 27 and 29 face each other toward the outer end faces 26 and 26 on the opposite side in the axial direction. Accordingly, the annular inclined surface is inclined so that the inner diameter becomes smaller. These inclined surfaces become rolling contact surfaces on which the intermediate roller 19 rolls. The inner peripheral surfaces 27a and 29a 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 supported by a support shaft (spinning shaft) 31 via a needle bearing 22 so as to be rotatable and displaceable in the axial direction. Each intermediate roller 19 is 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. Both ends of the rotation axis of the support shaft 31 are supported by the swing holder 32. The swing 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 11.

  For the support shaft 31, the material used for the shaft and the heat treatment applied are optimally selected so that the rocking holder 32 supports the intermediate roller 19 rotating around the input shaft 11 with high strength.

  The outer peripheral surface 19a of the intermediate roller 19 is a convex curved surface whose outer edge shape in the axial section is a single arc-shaped convex curve, and is in rolling contact with the outer peripheral surface 15a of the sun roller 15 and the inner peripheral surface 17a of the ring roller 17, respectively.

  The needle bearing 22 is a cage and roller having needle rollers 113 and a cage 115. The needle bearing 22 is provided with crown-shaped grooved collars 117 at both ends of the rotational axis thereof. Both ends of the grooved collar 117 are in contact with the swing holder 32 to position the needle bearing 22 in the direction of the rotation axis. In place of the needle bearing 22, both ends of the support shaft 31 of the intermediate roller 19 may be supported by ball bearings.

  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.

  Inside the cylindrical roller holding portion 39, 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, a stopper The ring 47 is inserted in this order, and these members are assembled to the roller holding portion 39.

  A plurality of concave grooves 43 are formed in the inner peripheral portion of the roller holding portion 39 along the axial direction, and a ring groove 45 (see FIG. 1) is formed.

  The concave groove 43 accommodates the protrusions 28 formed in a plurality of locations on the outer peripheral portion of the fixed ring roller element 27 and projecting in the radial direction. The protrusion 28 engages with the concave groove 43 of the roller holding portion 39 in a state where there is no rattling in the rotation direction, and enables transmission of rotational torque between the roller holding portion 39 and the fixed ring roller element 27.

  A retaining ring 47 is fitted into the ring groove 45. The retaining ring 47 restricts the axial position of the fixed ring roller element 27 and fixes the fixed ring roller element 27 to the roller holding portion 39.

  For example, the base end portion 37 of the connecting portion 21 is formed by cutting such as lathe processing, and the roller holding portion 39 is formed by plastic processing 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 made to coincide with each other at low cost with high accuracy by joining them together.

  The cam ring 49 has a plurality of protrusions 61 that protrude 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 groove 43 of the roller holding portion 39, respectively.

  The cam ring 49 has a notch 63 formed on the outer end surface on the output shaft 13 side, in which a part on the outer diameter side is notched in an annular shape, and a preload spring 67 is attached to the notch 63.

<Loading cam mechanism>
Next, the loading cam mechanism will be described.
The movable ring roller element 29, the cam ring 49, and the ball 51, which is a rolling element, constitute the loading cam mechanism 23 shown in FIG. 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 FIGS. 3 and 4, a plurality of (three in the illustrated example) first cam grooves 53 are formed on the outer end surface 26 of the movable ring roller element 29 along the circumferential direction. Similarly, a second cam groove 55 is formed for the cam ring 49. That is, the cam ring 49 is disposed facing the first cam groove 53, and a plurality of (three in the illustrated example) second cam grooves 55 are formed 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.

  The axial groove depths of the first cam groove 53 and the second cam groove 55 are deepest in the central portion with respect to the circumferential direction, and gradually change along the circumferential direction, so that the circumferential direction of the cam grooves 53 and 55 is increased. It becomes shallower toward the end.

  In a state where the input shaft 11 is stopped, as shown in FIG. 4A, each ball 51 is located at the deepest part of each cam groove. 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.

  When the input shaft 11 is driven to rotate, each ball 51 moves to a shallow portion of each cam groove 53, 55 as shown in FIG. As a result, an axial thrust force that presses the movable ring roller element 29 toward the fixed ring roller element 27 is generated. When the interval 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, the inner peripheral surface 17a of the ring roller 17 and the outer peripheral surface 19a of each intermediate roller 19 are reduced. As the surface pressure at the rolling contact portion increases, the surface pressure at the rolling contact portion between the outer peripheral surface 19a of each intermediate roller 19 and the outer peripheral surface 15a of the sun roller 15 also increases. As a result, the surface pressure of the plurality of rolling contact portions existing between the input shaft 11 and the output shaft 13 increases as the torque transmitted between the input shaft 11 and the output shaft 13 increases.

  Further, when the loading cam mechanism 23 generates axial thrust, the intermediate roller 19 is caused by the displacement of the movable ring roller element 29 in the axial direction due to elastic deformation of the traction components such as the ring roller 17 and elastic deformation of each contact point. It is displaced in the axial direction toward the fixed ring roller element 27 side.

<Intermediate roller and carrier structure and lubricating oil supply passage>
Next, the structure of the intermediate roller 19 and the carrier and the lubricating oil supply oil path in the friction roller type speed reducer 100 configured as described above will be described in more detail.

  FIG. 5 is a perspective view of the swing holder 32 that supports the intermediate roller. The intermediate roller 19 is supported by a swing holder 32 (see FIG. 2) at both ends of a support shaft 31 that is a rotation shaft. The same number of swing holders 32 as the intermediate rollers 19 are provided, and one intermediate roller 19 is supported by each swing holder 32. The swing holder 32 includes a pair of arm portions 71a and 71b that support both end portions of the support shaft 31, and a base portion 75 that connects the arm portions 71a and 71b. The pair of arm portions 71a, 71b and the base portion 75 are integrated to form a single swing holder 32. A rocking shaft 73 parallel to the support shaft 31 is inserted through the base 75.

  Since the intermediate roller 19 rotates at a high speed when power is transmitted to the input shaft 11, lubricating oil is always supplied. The friction roller type speed reducer 100 of this configuration supplies lubricating oil with an appropriate amount of oil to an appropriate supply position without complicating the lubricating oil supply oil path even when the intermediate roller 19 moves in the axial direction. It is possible.

  6 is a partial cross-sectional perspective view of the carrier 33 cut along a plane including the central axis of the swing shaft 73. FIG. 7 is a partial cross-sectional perspective view of the swing holder 32 cut along a plane including the central axis of the support shaft 31. It is.

  As shown in FIG. 6, the swing holder 32 is pivotally supported on the carrier 33 by a swing shaft 73. The carrier 33 is fastened and fixed to a housing (not shown) by fixing bolts.

  The housing has a lubricating oil supply passage, and has a lubricating oil supply port through which the lubricating oil is discharged. Lubricating oil is supplied to the drilling hole 123 by connecting the lubricating oil supply port of the housing to the drilling hole 123 opened at the one end 121 of the swing shaft 73 on the carrier 33 side. The perforation hole 123 is formed from one end portion 121 of the swing shaft 73 to at least an intermediate portion of the swing shaft 73 along the swing shaft 73.

  As shown in FIG. 7, the swing shaft 73 is inserted into the swing shaft support hole 149 of the swing holder 32. The swing shaft 73 is formed with communication holes 125 and 127 communicating with the drilled hole 123 in the radial direction. The communication hole 125 opens in an annular groove 129 formed on one end side of the swing shaft 73, and the communication hole 127 opens in an annular groove 131 formed in an intermediate position of the swing shaft 73.

  Shaft holes 133 and 135 for supporting the support shaft 31 of the intermediate roller 19 are formed at the distal ends of the pair of arm portions 71 a and 71 b of the swing holder 32. Further, the arm portion 71 a is formed with a rocking shaft support hole 149 at a position facing the annular groove 129 of the rocking shaft 73 and a communication hole 137 that connects the shaft hole 133. Further, the base 75 is formed with first injection supply holes 139 and 139 that communicate with the radially outer side facing the outer peripheral surface of the intermediate roller 19 from the annular groove 131.

  On the other hand, a perforation hole 141 is formed in the support shaft 31 along the support shaft 31. In the drill hole 141, second injection supply holes 143 and 143 that communicate with the outer side in the radial direction from the center of the drill hole 141 are formed in the middle portion of the support shaft 31. Further, a communication hole 145 is formed at a position corresponding to the communication hole 137 of the support shaft 31, and the communication hole 137 and the drilled hole 141 are communicated with each other. The opening end of the hole 141 is closed with a plug (not shown).

  One arm portion 71 a of the swing holder 32 is formed with a communication hole 137 and a tip hole 147 coaxial with the communication hole 137. These oil passages such as the perforated hole 123, the communication holes 125, 127, 145, the communication hole 137, the tip hole 147, the first injection supply hole 139, the second injection supply hole 143, and the like are subjected to construction methods such as cutting and electric discharge machining It is formed.

  The communication hole 137 and the tip hole 147 are formed to penetrate from the tip on the shaft hole 133 side where the support shaft 31 of the arm portion 71a is supported to the swing shaft support hole 149 where the swing shaft 73 is supported. Yes.

  A spring pin (not shown) for fixing the support shaft 31 is inserted into the tip hole 147 formed at the tip of the arm portion 71a.

  With the above configuration, the lubricating oil supplied from the housing side to the drilling hole 123 of the swing shaft 73 is filled into the annular groove 129 through the communication hole 125, and further, the support shaft 31 is drilled through the communication hole 137 and the communication hole 145. It is supplied to the hole 141. The lubricating oil supplied to the drill hole 141 is supplied to the needle bearing 22 from the second injection supply holes 143 and 143. The lubricating oil supplied to the needle bearing 22 passes through the gap of the retainer 115 shown in FIG. 1 and is discharged around the intermediate roller 19 through the notches of the grooved collar 117 at both ends of the needle bearing 22.

  Further, the lubricating oil is filled in the annular groove 131 from the hole 123 of the swing shaft 73 shown in FIG. 7 through the communication hole 127, and supplied to the outer peripheral surface 19a of the intermediate roller 19 through the first injection supply holes 139 and 139. Is done.

  FIG. 8 is a perspective view of the carrier 33 and the intermediate roller 19 as seen from the V1 direction of the friction roller type speed reducer 100 of FIG. The carrier 33 in the figure shows a state in which a connecting plate (not shown) that supports the swing shaft 73 is removed from the tip end portion 79 a of the column portion 79.

  The column portions 79 are arranged at equal intervals in the circumferential direction of the carrier 33. A plurality of swing holders 32 that support the intermediate roller 19 are disposed between the column portions 79. The swing shaft 73 of the swing holder 32 is inserted into a swing shaft hole (not shown) formed in the bottom portion 77 of the carrier 33 and a connecting plate (not shown) facing the bottom portion 77. As a result, the swing holder 32 is pivotally supported by the carrier 33 so as to be swingable about the swing shaft 73.

  As the swing holder 32 swings about the swing shaft 73, the intermediate roller 19 can be protruded and retracted radially outward of the carrier 33, and the influence of skew and tilt generated between the intermediate roller 19 and the ring roller 17. Can be canceled.

  Further, a plurality of bolt insertion holes 85 (three in the illustrated example) are formed in the column portion 79 of the carrier 33 along the axial direction for fixing the carrier 33 to the motor body.

<Relationship between rotation axis and swing axis of intermediate roller>
FIG. 9 is a plan view of the main part of the friction roller type speed reducer 100 of FIG. 1 viewed from the V1 direction.
The swing holder 32 of this configuration rotatably supports both ends of the support shaft 31 that is the rotation shaft of the plurality of intermediate rollers 19. These swing holders 32 are pivotally supported on the carrier 33 so as to be swingable around a swing shaft 73 parallel to the rotation shaft.

  The carrier 33 that supports the swing holder 32 is placed in a position different from the rotation axis of the intermediate roller 19 in the circumferential direction around the sun roller 15 in a plane perpendicular to the axial direction of the sun roller 15. The swing shaft 73 is arranged.

  The fixing bolt 35 for fixing the carrier 33 to the motor body passes through the bolt insertion hole 85 shown in FIG. 8 and is fastened to the motor body.

  The pitch bolt diameter D1 of the fastening member 35 centered on the axis O of the sun roller 15 of the fixing bolt 35 in the plan view in the axial direction and the swing axis centered on the axis O of the swing shaft 73 of the swing holder 32 The pitch circle diameter D2 at the center has a relationship of D1> D2. That is, the fixing bolt 35 is disposed radially outward from the axis O with respect to the swing shaft 73, and the fixing bolt 35 is disposed on the outer diameter side of the swing shaft 73.

  According to the above configuration, during the operation of the friction roller type speed reducer 100, the reaction force of the inter-roller transmission force acting on the intermediate roller 19 acts on the swing shaft 73 via the swing holder 32. As the transmission torque of the speed reducer increases, the reaction force of the rotational torque applied to the swing shaft 73 also increases. Even in this case, according to this configuration, the fixing bolt 35 serving as a fixing point is disposed outside the swing shaft 73 on which the reaction force acts. It can be made smaller than the reaction force acting on.

In addition, the tangent at the contact point Pc1 where the intermediate roller 19 and the sun roller 15 supported by the swing holder 32 are in rolling contact with each other is L ₀ , parallel to the tangent L ₀ and the intermediate roller 19 supported by the swing holder 32. when a straight line passing through the center of the support shaft 31 is a rotation axis and the first virtual straight line L _1, the pivot shaft 73 is disposed in the annular space sun roller 15 side of the first virtual straight line L ₁ .

FIG. 9 shows the first virtual straight line L ₁ for only one swing holder 32, but the same applies to the intermediate rollers 19, 19 of the other two swing holders 32.

Next, the balance of the force applied to the swing holder 32 having the above configuration will be described.
When the above-described friction roller type reduction gear (hereinafter abbreviated as a reduction gear) 100 transmits power, the reaction force of torque transmission of each roller acts on the arm portions 71a and 71b of the swing holder 32. The direction of action of the reaction force is the second line of the virtual straight line L ₂ connecting the center O ₂ of the center O ₁ and the swing axis 73 of the support shaft 31.

  The reaction force acting on the arm portions 71a and 71b becomes a compressive force or a tensile force depending on the configuration of the speed reducer 100 and its operating state, and therefore, here, the configuration and the operating state of the speed reducer 100 will be described.

The configuration of the speed reducer 100 is classified into two based on the rotation direction of the sun roller 15 when the vehicle starts (and when traveling at a constant speed).
(Configuration 1) When the vehicle moves forward, the sun roller 15 rotates in the clockwise (CW) direction.
(Configuration 2) When the vehicle moves forward, the sun roller 15 rotates counterclockwise (CCW).

  The driving state includes forward or reverse, and acceleration, constant speed, and deceleration. Table 1 shows combinations of these operating states and configurations 1 and 2.

  As shown in Table 1, compression force is applied to the arm portions 71a and 71b in the configuration 1 during forward deceleration, reverse acceleration, and constant reverse speed, and in the configuration 2, during forward acceleration, constant forward speed, and reverse deceleration. In other cases, a tensile force acts on the arm portions 71a and 71b.

  The torque generated when traveling at a constant speed is a torque necessary for the vehicle to maintain a constant speed, and has a smaller value than the torque generated during acceleration. Since the regenerative brake works when the vehicle is decelerated, the rotation direction of the rollers of the speed reducer 100 remains the same as the forward direction, and the torque load direction is reversed. Since the sun roller is driven in reverse when the vehicle is moving backward, the torque load direction is reversed from that when moving forward.

  Here, the balance state of the force when a tensile force acts on the arm portions 71a and 71b will be described. FIG. 10 is an explanatory diagram showing the force acting on one swing holder 32 and the intermediate roller 19 shown in FIG.

  For example, if the speed reducer 100 of configuration 1 is in the A1 operation state, the sun roller 15 is driven in the CW direction, and the tangential force Fs acts on the intermediate roller 19 at the contact point Pc1 between the sun roller 15 and the intermediate roller 19. . Further, when the intermediate roller 19 receives the rotational force from the sun roller 15 and rotates in the CCW direction, the tangential force Fr is intermediate at the contact point Pc2 between the intermediate roller 19 and the ring roller 17 by the ring roller 17 on the driven side. It acts on the roller 19.

  Then, the resultant force Fp (= Fs + Fr) of the tangential force Fs and Fr acts on the support shaft 31 of the arm portions 71a and 71b that support the intermediate roller 19. This resultant force Fp becomes a torque transmission force that one intermediate roller 19 bears. This torque transmission force Fp can be decomposed into a component force Fpa along the axial direction of the arm portions 71a and 71b and a component force Fpb perpendicular to the axial direction of the arm portion 71a.

  As shown in FIG. 11, the component force Fpa along the axial direction of the disassembled arm portions 71a and 71b acts on the swing shaft 73 as its reaction force Ft. In the case of this configuration, the reaction force Ft is smaller than the torque transmission force Fp, and the load acting on the swing shaft 73 can be kept small.

  Next, the force balance state when the compressive force acts on the arm portions 71a and 71b will be described. FIG. 12 is an explanatory diagram showing the force acting on one swing holder 32 and the intermediate roller 19 shown in FIG.

  For example, if the speed reducer 100 of configuration 2 is in the A1 operation state, the sun roller 15 is driven in the CCW direction, and the tangent line in the direction opposite to that in FIG. 10 is at the contact point Pc1 between the sun roller 15 and the intermediate roller 19. A force Fs acts on the intermediate roller 19. Further, when the intermediate roller 19 receives the rotational force from the sun roller 15 and rotates in the CW direction, at the contact point Pc2 between the intermediate roller 19 and the ring roller 17, the ring roller 17 on the driven side causes the case of FIG. A reverse tangential force Fr acts on the intermediate roller 19.

  Then, a resultant force Fp (= Fs + Fr) of the tangential force Fs and Fr acts on the support shaft 31 of the arm portions 71a and 71b that support the intermediate roller 19. This resultant force Fp becomes a torque transmission force that one intermediate roller 19 bears. This torque transmission force Fp can be decomposed into a component force Fpa along the axial direction of the arm portions 71a and 71b and a component force Fpb orthogonal to the axial direction.

  As shown in FIG. 13, the component force Fpa along the axial direction of the disassembled arm portions 71 a and 71 b acts on the swing shaft 73 as the reaction force Ft. In the case of this configuration, the reaction force Ft is smaller than the torque transmission force Fp, and the load acting on the swing shaft 73 can be kept small.

For this configuration example, a support shaft 31 of the swing shaft 73 and the intermediate roller, as shown in FIG. 9, the pivot shaft 73 to the positional relationship disposed on the sun roller 15 side of the first virtual straight line L ₁ ing. According to this arrangement, the swinging shaft 73 acts on the swinging shaft 73 as compared with the case where the swinging shaft 73 is installed on a line parallel to the tangent line of the intermediate roller 19 and the sun roller 15 and passing through the support shaft 31 of the intermediate roller 19. The load can be reduced.

  Therefore, the stress generated in the arm portions 71a and 71b can be reduced, and the strength is maintained without greatly increasing the rigidity of the arm portions 71a and 71b. Therefore, it is not necessary to increase the thickness of each member in order to ensure strength, and the reduction gear 100 can be reduced in size and weight. In addition, the amount of change in the support position due to the elastic deformation of the intermediate roller 19 is suppressed, and a reduction in power transmission efficiency can be prevented. Therefore, stable deceleration operation can be performed, and the reliability of the speed reducer 100 can be improved.

  Further, in the case of the above configuration example, when a load in the compression direction acts on the arm portions 71 a and 71 b of the swing holder 32, the arm portions 71 a and 71 b between the support shaft 31 and the swing shaft 73 are elastically deformed. In contrast, when a load in the tensile direction acts on the arm portions 71a and 71b, in addition to the elastic deformation of the arm portions 71a and 71b between the support shaft 31 and the swing shaft 73, a fitting hole with the swing shaft 73 is provided. The edge portions of the arm portions 71a and 71b are also elastically deformed greatly. The elastic deformation of the tip portions of the arm portions 71a and 71b increases to a degree that cannot be ignored.

  When the intermediate roller 19 is pulled in a direction away from the swing shaft 73, the arm portions 71 a and 71 b are subjected to a large tensile force on the distal end portion of the arm portions 71 a and 71 b opposite to the swing shaft 73. In particular, when a tensile stress acts on the arm portion 71a, stress concentration tends to occur at the opening portion of the tip hole 147 (see FIGS. 5 and 7).

  Moreover, the said front-end | tip part of arm part 71a, 71b is comparatively thin, and when a tensile force acts, distortion larger than the case where arm part 71a, 71b is compressed will arise.

  Therefore, the amount of change in the support position of the intermediate roller 19 due to the elastic deformation of the swinging holder 32 is larger during tension than when the arms 71a and 71b are compressed.

Therefore, the positional relationship between the supporting shaft 31 of the swing shaft 73 and the intermediate roller 19, as shown in FIG. 9 described above, placing the pivot shaft 73 to the sun roller 15 side of the first virtual straight line L ₁ In addition to the above, it is preferable that the state of the force acting on the arm portions 71a and 71b is a state in which the compression force shown in FIG. 12 is generated.

  Specifically, as shown in Table 1 above, in the configuration 1, the forward deceleration, the reverse acceleration, and the constant reverse speed are set, and in the configuration 2, the forward acceleration, the constant forward speed, and the reverse deceleration are set. A compressive force acts on the arm portions 71a and 71b.

  Therefore, according to the design policy that places importance on the forward deceleration, reverse acceleration, and constant reverse speed of the vehicle, the sun roller 15 is designed to rotate in the CW direction in FIG. 9 when the vehicle moves forward. In this case, the stress generated at the tips of the arm portions 71a and 71b does not become excessive when the regenerative brake is used or from the reverse start to the constant speed.

  Therefore, the arm portions 71a and 71b do not have to be highly rigid, and the swing shaft 73 and the swing holder 32 can be reduced in size and weight. Further, since the amount of change in the support position of the intermediate roller 19 is small, slippage between the rollers is difficult to occur, and a decrease in torque transmission efficiency can be suppressed. In particular, the reduction in the regeneration efficiency can be prevented by suppressing the amount of change in the support position of the intermediate roller 19 when the regenerative brake is activated.

  On the other hand, in the design policy that places importance on the conditions of forward acceleration, forward constant speed, and reverse deceleration of the vehicle, the sun roller 15 is designed to rotate in the CCW direction in FIG. In this case, the stress generated at the tips of the arm portions 71a and 71b is not excessive from the forward acceleration to the forward constant speed traveling and when the vehicle is decelerated backward.

  Therefore, the arm portions 71a and 71b do not have to be highly rigid, and the swing shaft 73 and the swing holder 32 can be reduced in size and weight. Further, since the amount of change in the support position of the intermediate roller 19 is small, slippage between the rollers is difficult to occur, and a decrease in torque transmission efficiency can be suppressed. In particular, the amount of change in the support position of the intermediate roller 19 during frequent forward drive can be suppressed to a small level, so that the responsiveness of the drive device can be improved and the reduction in power transmission efficiency can be prevented.

  Generally, when the vehicle suddenly accelerates or when the accelerator pedal is released while the vehicle is running, the power input to the speed reducer changes suddenly and the load direction is reversed. In particular, in the case of an electric vehicle, there is a tendency to actively use a regenerative brake for the purpose of improving power consumption.

  In the above case, generally, the support position of the intermediate roller 19 changes and the reduction ratio changes instantaneously, which affects the vehicle driving characteristics. However, according to the speed reducer 100 of this configuration, even if the power input to the speed reducer changes suddenly, the stress along the axial direction of the arm portions 71a and 71b is relieved. Impact is reduced.

<Inclination angle of the arm>
Next, the inclination angle θ of the arm portions 71a and 71b of the swing holder 32 will be described. As shown in FIG. 14, a virtual straight line L ₁ that is a perpendicular line of a _third virtual straight line L ₃ that connects the center O _s of the sun roller 15 and the center O ₁ of the support shaft 31 of the intermediate roller 19, and the intermediate roller 19 the angle between the center O ₁ and the virtual straight line L ₂ second connecting the center O ₂ of the swinging shaft 73 of the support shaft 31 and the inclination angle theta.

  At this time, the load Fpa applied to the arm portions 71a and 71b is obtained from the tangential forces Fs and Fr (F = Fs = Fr) at the contact points Pc1 and Pc2 by the following equation.

  Fpa = 2Fcosθ

  From the above equation, it can be seen that the larger the inclination angle θ of the arm portions 71a and 71b, the smaller the load applied to the arm portions 71a and 71b. That is, by setting the inclination angle θ large, it is possible to reduce the load applied to the arm portions 71a and 71b, and to improve the reliability and size and weight of the swing holder 32.

Further, as shown in FIG. 14, in the annular space between the ring roller 17 and the sun roller 15, the third virtual straight line L <b> 3 is orthogonal to the third virtual straight line L <b> 3 and passes through the center Os of the sun roller 15. surrounded by a fourth virtual line L _4, the arm portion 71a of the third imaginary straight line L3, the 71b of the extension side of the region W (region shown in FIG hatch), placing the pivot shaft 73 Is preferred. By arranging the pivot axis 73 than the fourth virtual line L ₄ to the intermediate roller 19 side, can reduce the size of the pivot holder 32, it can be made more compact configuration.

  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.

  In the friction roller type speed reducer 100 configured as described above, the ring roller 17 is constituted by a pair of ring roller elements, and one ring roller element is moved in the axial direction by a loading cam mechanism. 15 may be configured by a pair of sun roller elements, and one of the sun roller elements may be moved in the axial direction by a loading cam mechanism.

  Moreover, although the said friction roller type reduction gear 100 demonstrated to the example the case where it applied to drive devices for electric vehicles, such as an electric vehicle and a hybrid vehicle, it is applicable not only to this but in an industrial machine, for example.

11 Input shaft 13 Output shaft 15 Sun roller 17 Ring roller 19 Intermediate roller 23 Loading cam mechanism 31 Support shaft (spinning shaft)
32 swing holder 33 carrier 71a, 71b arm portion 73 swing shaft 100 friction roller type speed reducer

Claims (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 an annular space 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,
A plurality of swing holders for rotatably supporting both end portions of the rotation shafts of the plurality of intermediate rollers;
A carrier that pivotally supports the swing holder so that it can swing around a swing axis parallel to the rotation axis;
With
The carrier has a swing shaft disposed at a circumferential position different from the rotation shaft in a circumferential direction around the sun roller in a plane perpendicular to the axial direction of the sun roller, and is supported by the swing holder. When the straight line that is parallel to the tangent at the contact point where the intermediate roller and the sun roller are in rolling contact with each other and that passes through the rotation axis of the intermediate roller is a virtual straight line, the sun roller side from the virtual straight line A friction roller type speed reducer characterized in that the rocking shaft is disposed in the annular space.

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