JP2014108742A - Power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission device which can smoothly switch from a two-wheel drive state to a four-wheel drive state.SOLUTION: Power is transmitted to a rear-wheel drive system by an output shaft 103, and in a clutch 2, which transmits the power of the output shaft 103 to a front-wheel drive system so that the power can be cut off, a first roller 6 is interposed between a first inner ring 3 and an outer ring 5. When the first roller 6 is locked to switch a rear-wheel drive (two-wheel drive) state to a four-wheel drive state, the first roller 6 rolls between the first inner ring 3 and the outer ring 5, and the first inner ring 3 and the outer ring 5 are elastically deformed in the radial direction. Since impact occurring at the switching is absorbed by the rolling of the first roller 6 and the elastic deformation of the first inner ring 3 and the outer ring 5, smooth switching from the two-wheel drive state to the four-wheel drive state can be performed.

Description

  The present invention relates to a power transmission device for a four-wheel drive vehicle, and more particularly to a power transmission device that can be smoothly switched from a two-wheel drive state to a four-wheel drive state.

  Conventionally, in a power transmission device for a four-wheel drive vehicle having a rear wheel as a main drive wheel, when the rotational speed of the rear wheel drive system is larger than the rotational speed of the front wheel drive system, the one-way clutch is engaged and the front wheel drive system There is known a technique for transmitting power to the vehicle (for example, Patent Document 1). In the technique disclosed in Patent Document 1, if the rotational speed of the rear wheel drive system becomes larger than the rotational speed of the front wheel drive system, for example, due to slippage of the rear wheel during rear wheel drive traveling, the one-way clutch is engaged and the front wheel is engaged. Power is transmitted to the drive system. As a result, since the two-wheel drive state in which the rear wheel drive system is driven changes to the four-wheel drive state in which both the front wheel drive system and the rear wheel drive system are driven, the traction performance can be maintained high.

JP 2000-142152 A

  However, in the technique disclosed in Patent Document 1, the one-way clutch is configured to include a plurality of sprags arranged in the space between the output shaft and the clutch hub (see Paragraph 0056 and FIG. 5 of Patent Document 1). ) When the sprags bite into the output shaft and the clutch hub, the sprags are locked and power is transmitted. Accordingly, when the rotational speed of the rear wheel drive system becomes larger than the rotational speed of the front wheel drive system, the sprags instantly bite into the output shaft and the clutch hub, and a shock is generated by the inertia torque of the front wheel drive system. Therefore, there is a problem that switching from the two-wheel drive state to the four-wheel drive state cannot be performed smoothly.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a power transmission device for a four-wheel drive vehicle that can be smoothly switched from a two-wheel drive state to a four-wheel drive state.

Means for Solving the Problems and Effects of the Invention

  In order to achieve this object, according to the power transmission device for a four-wheel drive vehicle according to claim 1, the power from the drive source is transmitted to the rear wheel drive system by the output shaft, while the power of the output shaft is transmitted to the front wheel. The clutch includes a clutch that transmits to the drive system in a shuttable manner, and the clutch has a first inner ring disposed radially outside the output shaft, and a first outer ring disposed radially outside the first inner ring. The A first inner raceway surface is formed on the inner peripheral surface of the first outer ring, and a first outer raceway surface facing the first inner raceway surface is formed on the outer peripheral surface of the first inner ring. The plurality of first rollers interposed between the first outer raceway surface and the first inner raceway surface are circumferentially inclined by a predetermined angle from the surface including the axis of the output shaft by the first cage. They are held at a distance from each other.

  Since one of the first inner ring and the first outer ring is configured to be able to rotate integrally with the output shaft, when the power from the drive source is transmitted to the output shaft, the power is transmitted to one of the first inner ring or the first outer ring and the rear. It is transmitted to the wheel drive system. Since the other of the first inner ring or the first outer ring is configured to be rotatable relative to one of the first inner ring or the first outer ring, power is transmitted to one of the first inner ring or the first outer ring, and the first When relative rotation in a predetermined direction is applied to the inner ring and the first outer ring, the first roller revolves around the output shaft while rotating along the first inner raceway surface and the first outer raceway surface. Guided by the rotation of the first roller, the other of the first inner ring or the first outer ring moves in the axial direction relative to one of the first inner ring or the first outer ring while elastically deforming in the radial direction. When the plurality of first rollers engage with the first inner raceway surface and the first outer raceway surface, the first inner ring, the first outer ring, and the first roller rotate together to transmit the rotational power.

  The other of the first inner ring or the first outer ring includes a sprocket or gear that can rotate integrally with the other of the first inner ring or the first outer ring. The sprocket engages with a chain that transmits power to the front wheel drive system. Since the chain can be displaced in the direction crossing the winding direction, it can follow the other axial movement of the first inner ring or the first outer ring.

  Further, the gear is formed with teeth having a predetermined twist angle so that the tooth trace is not parallel to the shaft center, and is engaged with a driven gear that transmits power to the front wheel drive system. The torsional direction of the gear is determined by the direction of the thrust force generated in the gear when it is engaged with the driven gear and transmitting power, and the first roller is engaged with the first inner raceway surface and the first outer raceway surface. Is set to coincide with the direction in which the other of the first inner ring or the first outer ring moves. Therefore, when the gear moves in the axial direction along with the other axial movement of the first inner ring or the first outer ring, the other axial direction of the first inner ring or the first outer ring is caused by the thrust force of the gear due to the torsion angle of the tooth surface. It is possible to prevent the movement from being restricted.

  As described above, by providing the sprocket or gear that can rotate integrally with the other of the first inner ring or the first outer ring, it is possible to prevent the other of the first inner ring or the first outer ring from moving in the axial direction. That is, the first inner raceway surface and the first outer circumference raceway surface can be prevented from being unable to engage with the first roller. Therefore, when the rotational speed of the rear wheel drive system is larger than the rotational speed of the front wheel drive system, the first inner ring Further, the first roller is engaged with the first outer wheel, and the four-wheel drive state in which the power of the output shaft is transmitted to the front wheel drive system can be achieved.

  When the first roller engages with the first inner ring and the first outer ring, the first roller rolls on the first outer raceway surface of the first inner ring and the first inner raceway surface of the first outer ring, and the first outer ring. The raceway surface and the first inner circumference raceway surface are elastically deformed in the radial direction. Since the impact at the time of switching is absorbed by the rolling of the first roller and the elastic deformation of the first inner ring and the first outer ring, there is an effect that the two-wheel drive state can be smoothly switched to the four-wheel drive state.

  According to the power transmission device of the second aspect, in the clutch, the second inner ring disposed on the radially outer side of the output shaft is juxtaposed in the axial direction of the first inner ring, and on the radially outer side of the second inner ring. The arranged second outer ring is juxtaposed in the axial direction of the first outer ring. A second inner peripheral raceway surface is formed on the inner peripheral surface of the second outer ring, and a second outer peripheral raceway surface facing the second inner peripheral raceway surface is formed on the outer peripheral surface of the second inner ring. A plurality of second rollers are interposed between the second outer raceway surface and the second inner circumference raceway surface. The plurality of second rollers are held by the second cage while being spaced apart from each other in the circumferential direction while being inclined at a predetermined angle from the surface including the axis of the output shaft, and in a direction opposite to the direction in which the first rollers are engaged. Rotational power is transmitted by engaging the second inner raceway surface and the second outer raceway surface by relative rotation of the second inner ring and the second outer ring.

  One of the second inner ring or the second outer ring is configured to be rotatable integrally with the output shaft, and the other of the second inner ring or the second outer ring is rotatable relative to one of the second inner ring or the second outer ring and in the axial direction. It is configured to allow relative movement. Since the other of the second inner ring or the second outer ring is configured to rotate integrally with the other of the first inner ring or the first outer ring together with the sprocket or the gear, the first inner ring, the first outer ring, and the first roller when traveling forward. Is set to be engageable, the second inner ring, the second outer ring, and the second roller can be set to be engageable during coasting travel and reverse travel. Since the other of the first inner ring or the first outer ring and the second inner ring or the second outer ring arranged in parallel to each other can be moved in the axial direction by the moving means, the forward traveling, the coasting traveling, the reverse traveling The drive wheels can be switched as appropriate. Therefore, in addition to the effect of the first aspect, there is an effect of widening the selection range of the drive wheels.

  According to the power transmission device of the third aspect, the moving means is the other of the first inner ring or the first outer ring and the second arranged in parallel to the other of the first inner ring or the first outer ring by a driving force of a solenoid that reciprocates or a motor that rotates. Since the inner ring or the second outer ring moves in the axial direction, in addition to the effect of the second aspect, there is an effect that the power transmission device can be reduced in size and weight.

  According to the power transmission device of the fourth aspect, the axial direction of the first inner ring or the first outer ring when the first roller is engaged with the first inner raceway surface and the first outer raceway surface to transmit rotational power. The first inner ring or the first outer ring is urged by the first elastic member in the moving direction. When releasing the engagement between the first inner raceway surface and the first outer raceway surface and the first roller, the first urging release means operates the solenoid or the motor so that the first inner ring by the first elastic member or The bias of the first outer ring is released. As a result, in addition to the effect of the third aspect, the solenoid or the motor can be operated to release the engagement between the first inner raceway surface and the first outer raceway surface and the first roller, thereby interrupting the transmission of rotational power. effective.

  According to the power transmission device of claim 5, the first inner ring or the first inner ring or the first outer ring surface in the axial direction is prevented by the second elastic member in a direction to prevent the first inner raceway surface and the first outer raceway surface from engaging with the first roller. The first outer ring is biased. When the first roller is engaged with the first inner raceway surface and the first outer raceway surface, the solenoid or motor is operated by the second urging release means, and the first inner ring or the first outer ring by the second elastic member. Is released. As a result, in addition to the effect of the third aspect, there is an effect that the solenoid or the motor is operated to engage the first inner peripheral raceway surface and the first outer peripheral raceway surface with the first roller, thereby transmitting the rotational power.

  According to the power transmission device of the sixth aspect, the amount of axial movement of the first inner ring or the first outer ring when the first roller engages with the first outer raceway surface and the first inner raceway surface is the movement restricting means. Therefore, when an excessive torque (peak torque) that cannot be transmitted unless it moves in the axial direction beyond the regulated axial movement amount is input to the output shaft, the first roller It becomes impossible to engage with the outer peripheral raceway surface and the first inner peripheral raceway surface. Thereby, since it is possible to prevent the peak torque from being transmitted to the front wheel drive system, in addition to the effect of any one of claims 1 to 5, it is not necessary to design the structure of the front wheel drive system in consideration of the peak torque, The front wheel drive system can be reduced in size and weight.

  According to the power transmission device of the seventh aspect, the intermittent means for intermittently transmitting the power is disposed in the power transmission path from the clutch to the front wheel drive system. By stopping the rotation of the front wheel drive system by the intermittent means, it is possible to eliminate friction loss due to rotation during two-wheel drive (rear wheel drive) and energy loss due to oil agitation in the unit. As a result, in addition to the effect of any one of claims 1 to 6, it is possible to improve the fuel efficiency during rear wheel drive (two-wheel drive state). When four-wheel drive is required, the four-wheel drive state can be achieved by fastening the clutch and increasing the rotational speed of the front-wheel drive system, and then fastening the intermittent means. There is an effect.

It is a skeleton figure which shows typically the 4 wheel drive vehicle carrying a power transmission device. It is an axial sectional view of the clutch of the power transmission device in the first embodiment. It is an axial sectional view of the clutch after the travel mode is switched. It is a schematic diagram which shows mesh | engagement of a gear. It is an axial sectional view of a clutch of a power transmission device in a second embodiment. It is an axial sectional view of the clutch after the travel mode is switched. (A) is an axial sectional view of the clutch after switching to the traveling mode, and (b) is an axial sectional view of the clutch after switching to another traveling mode. It is an axial sectional view of a clutch of a power transmission device in a third embodiment. (A) is an axial sectional view of the clutch after switching to the traveling mode, and (b) is an axial sectional view of the clutch after switching to another traveling mode. It is an axial sectional view of a clutch in a 4th embodiment. (A) is an axial sectional view of the clutch after switching to the traveling mode, and (b) is an axial sectional view of the clutch after switching to another traveling mode.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. First, a four-wheel drive vehicle 100 on which the power transmission device 1 is mounted will be described with reference to FIG. FIG. 1 is a skeleton diagram schematically showing a four-wheel drive vehicle 100 on which the power transmission device 1 is mounted. As shown in FIG. 1, in the four-wheel drive vehicle 100, an engine 101 and a transmission 102 joined to the engine 101 are arranged in the front, and the power is transmitted to the left via an output shaft 103 and a rear wheel differential device 104. This is transmitted to the rear wheel drive shaft 105 and the right rear wheel drive shaft 106. The rear wheel differential device 104 absorbs the rotation speed when a difference in rotational speed occurs between the left and right rear wheels 107 due to cornering, a change in road surface condition, or the like, and the left rear wheel drive shaft 105 and the right rear wheel drive shaft 106 are absorbed. And the left and right rear wheels 107 are rotated to transmit the driving force to the road surface.

  The output shaft 103 is provided with a power transmission device 1 including a clutch 2 that transmits the power of the output shaft 103 to the front wheel drive system so as to be cut off. The power of the output shaft 103 is transmitted to the front drive shaft 111 via the driven gear 112 that meshes with the gear 5 a of the power transmission device 1 and is transmitted to the front wheel differential device 113.

  The power transmitted to the front wheel differential device 113 via the front drive shaft 111 is transmitted to the left front wheel drive shaft 114 and the right front wheel first drive shaft 115, and to the right front wheel second drive shaft 117 via the intermittent device 116. Communicated. When the left front wheel drive shaft 114 and the right front wheel second drive shaft 117 are driven, the left and right front wheels 118 rotate and the driving force is transmitted to the road surface. It should be noted that the front wheel differential device 113 absorbs the rotation speed and generates a left front wheel drive shaft 114 and a right front wheel first drive shaft 115 when a difference in rotation speed occurs between the left and right front wheels 118 due to cornering or changes in road surface conditions. Drive.

  The intermittent device 116 is means for interrupting transmission of power between the right front wheel first drive shaft 115 and the right front wheel second drive shaft 117, and a spline groove 116 a formed on the outer periphery of the right end of the right front wheel first drive shaft 115. The spline groove 116b formed on the outer periphery of the left end of the right front wheel second drive shaft 117, the sleeve 116c disposed on the radially outer side of the spline grooves 116a and 116b, and the tip of the sleeve 116c are slidable in the outer periphery groove. And an actuator 116d that slides a shift fork that engages in the axial direction of the sleeve 116c. The sleeve 116c is configured to be able to move between a connection position where the spline grooves 116a and 116b are connected by spline coupling and a cutting position where the connection is released.

  The four-wheel drive vehicle 100 enters the four-wheel drive mode when the clutch 2 is connected, the rotation of the drive system components from the clutch 2 to the intermittent device 116 is increased, and then the intermittent device 116 is connected. If the engagement of the clutch 2 is released and the intermittence device 116 is disconnected, the two-wheel drive (rear wheel drive) mode is established, and the right front wheel first drive shaft 115 and the front right wheel first drive shaft of the front wheel differential device 113 are set. Since the rotation of the gear on the 115 side can be stopped, it is possible to prevent a reduction in fuel consumption due to the friction loss.

  Next, the clutch 2 of the power transmission device 1 will be described with reference to FIG. FIG. 2 is an axial sectional view of the clutch 2 of the power transmission device 1 according to the first embodiment. In addition, in order to make an understanding easy, illustration of the thrust bearing etc. which receive an axial force is abbreviate | omitted (this illustration abbreviation is the same in 2nd Embodiment to 4th Embodiment). The clutch 2 is a device that transmits and blocks power between the output shaft 103 and the front drive shaft 111 (see FIG. 1).

  As shown in FIG. 2, the clutch 2 is arranged in parallel with the first inner ring 3 disposed on the radially outer side of the output shaft 103 and the axial direction of the first inner ring 3 and disposed on the radially outer side of the output shaft 103. The second inner ring 4 provided, the outer ring 5 disposed radially outside the first inner ring 3 and the second inner ring 4, and the outer ring 5, the first inner ring 3 and the second inner ring 4 are interposed. A plurality of first rollers 6 and second rollers 7, and a first holder 8 and a second holder 9 that hold the first roller 6 and the second roller 7, respectively.

  The first inner ring 3 is an annular member that has a function of transmitting rotational power, and a first outer raceway surface 3a that forms a single leaf rotation hyperboloid around the axis O is formed on the outer circumference. The first inner ring 3 is restricted from rotating with respect to the output shaft 103 by a spline, and is allowed to move in the axial direction with respect to the output shaft 103. The output shaft 103 has a disk-like stopper 10 extending radially outward from the outer peripheral surface, and is erected on one axial side of the first inner ring 3 (left side in FIG. 2), and is rotated integrally with the output shaft 103. At the same time, it is provided so as not to move in the axial direction. A disc spring 11 (elastic member) is inserted between the stopper 10 and one axial end of the first inner ring 3. As a result, the first inner ring 3 is urged toward the other axial side (the right side in FIG. 2) with respect to the stopper 10. The first outer raceway surface 3a is reduced in diameter as it is separated from the stopper 10 to the other side in the axial direction.

  The second inner ring 4 is an annular member having a function for transmitting rotational power, and a second outer circumferential raceway surface 4a forming a single leaf rotation hyperboloid around the axis O is formed on the outer circumferential surface. The second inner ring 4 is restricted from rotating with respect to the output shaft 103 by the spline, and is allowed to move in the axial direction with respect to the output shaft 103. In the output shaft 103, a disc-shaped stopper 12 extending from the outer peripheral surface toward the radially outer side is erected on the other axial side of the second inner ring 4 (right side in FIG. 2).

  The second inner ring 4 is disposed on the output shaft 103 so that one end surface in the axial direction (left side surface in FIG. 2) is in contact with the other end surface in the axial direction of the first inner ring 3 (right side surface in FIG. 2). Accordingly, the second inner ring 4 is urged to the other axial side (right side in FIG. 2) by the first inner ring 3 urged to the other axial side (right side in FIG. 2) by the disc spring 11. The axial position of the second inner ring 4 is determined by the position of the stopper 12. The second outer raceway surface 4a is reduced in diameter as it is separated from the stopper 12 to one side in the axial direction (left side in FIG. 2).

  The stopper 12 is rotated integrally with the output shaft 103 and is provided so as not to move in the axial direction, and a plurality of holes 12a are formed through the axial direction. The hole 12 a is a part through which a pin 18 (described later) configured to be movable in the axial direction is inserted, and the pin 18 is inserted from the hole 12 a against the biasing force of the disc spring 11 in the axial direction of the stopper 12. By projecting to one side (left side in FIG. 2), the first inner ring 3 and the second inner ring 4 can be moved to an arbitrary axial position between the stoppers 10 and 12.

  The outer ring 5 is a member having a function for transmitting rotational power together with the first inner ring 3 and the second inner ring 4, and is disposed on the radially outer side of the first inner ring 3 and the second inner ring 4. Since the outer ring 5 is integrally provided outside the first inner ring 3 and the second inner ring 4 in the radial direction over the axial length of the first inner ring 3 and the second inner ring 4, the outer ring 5 can be made robust and has a simple structure. Can be The outer ring 5 has an inner circumference in which a first inner raceway surface 5a and a second inner circumference raceway surface 5b that form a single-leaf rotating hyperboloid around an axis O are opposed to the first outer circumference raceway surface 3a and the second outer circumference raceway surface 4a. Each surface is formed. The first inner circumferential raceway surface 5a and the second inner circumferential raceway surface 5b are formed such that the inner diameter gradually increases from the axial center of the outer ring 5 toward both axial sides. The outer ring 5 is provided with a gear 5a on the outer peripheral surface. The gear 5a is a part that meshes with the driven gear 112 formed on the outer periphery of the rear end of the front drive shaft 111 (see FIG. 1).

  The outer ring 5 is configured to be rotatable relative to the first inner ring 3 and the second inner ring 4 and to be relatively movable in the axial direction, and step portions 5d and 5e formed in a step shape radially inward at both axial ends. By abutting against the axial end surface on the radially outer side of the stoppers 10 and 12, further axial movement is restricted. The stoppers 10 and 12 stop the axial movement of the outer ring 5 at a fixed position when the first roller 6 is engaged and screwed into the first outer raceway surface 3a and the first inner raceway surface 5a. It has a function of a torque limiter that prevents a torque exceeding a certain level from being applied, and a function of preventing the first roller 6 and the second roller 7 from slipping out.

  The first roller 6 is a cylindrical member that engages with the first inner ring 3 and the outer ring 5 to transmit rotational power, and a plurality of first rollers 6 are interposed between the first inner ring 3 and the outer ring 5. The plurality of first rollers 6 are held between the first outer raceway surface 3a and the first inner circumference raceway surface 5a by a first cage 8 disposed between the first inner ring 3 and the outer ring 5. .

  The first cage 8 is a member for holding the first roller 6 at a distance from each other so that the first roller 6 rotates smoothly without interfering with each other. The first roller 6 is inclined at a certain angle (for example, 15 °) from the surface including the axis O by the first cage 8 (set to a constant skew angle with respect to the axis O), and the first outer circumferential track. A plurality of circumferential surfaces of the surface 3a and the first inner circumferential raceway surface 5a are arranged, and the outer circumferential surface is arranged in a linear contact (line contact) with the first outer circumferential raceway surface 3a and the first inner circumferential raceway surface 5a. The

  The second roller 7 is a cylindrical member that engages with the second inner ring 4 and the outer ring 5 to transmit rotational power, and a plurality of second rollers 7 are interposed between the second inner ring 4 and the outer ring 5. The plurality of second rollers 7 are held between the second outer raceway surface 4 a and the second inner raceway surface 5 b by a second cage 9 disposed between the second inner ring 4 and the outer ring 5. .

  The second cage 9 is a member for holding the second roller 7 at a distance from each other so that the second roller 7 rotates smoothly without interfering with each other. The second roller 7 is inclined at a constant angle (for example, 15 °) in the same direction as the first roller 3 from the surface including the axis O by the second cage 9 (with a constant skew angle with respect to the axis O). A plurality of second outer peripheral raceway surfaces 4a and second inner peripheral raceway surfaces 5b are arranged in the circumferential direction, and the outer peripheral surfaces are in linear contact with the second outer peripheral raceway surface 4a and the second inner peripheral raceway surface 5b. (Line contact) It is arranged to be possible.

  The moving means 13 is a means for moving the first inner ring 3 and the second inner ring 4 in the axial direction in conjunction with each other, and the solenoid 14 arranged away from the stopper 12 in the axial direction and the reciprocating motion of the solenoid 14. And a pin 18 that appears and disappears. The solenoid 14 is a device for reciprocating the rod 15 extending toward the stopper 12 in the axial direction. The solenoid 14 is disposed between the solenoid 14 and the stopper 12 and is connected to the other side of the arm 16 on which one end 16a is pivotally supported. The tip of 15 is abutted. Since the other end of the arm 16 on which the one end 16a is pivotally supported is biased toward the rod 15 (counterclockwise in FIG. 2), the arm 16 reciprocates around the one end 16a as the rod 15 reciprocates.

  The moving plate 17 is an annular member that is linked to the other side of the arm 16. The output plate 103 is provided through the moving plate 17, and is configured to be movable in the axial direction along with the reciprocating rotation of the arm 16. Further, the moving plate 17 is disposed so that one end surface thereof is in contact with the axial end surface of the pin 18 penetrating the stopper 12. The pin 18 is a member that is loosely inserted into a hole 12 a that is formed to penetrate the stopper 12 in the axial direction. The axial length of the pin 18 is set larger than the axial thickness of the stopper 12. Therefore, when the moving plate 17 moves to one side in the axial direction (left side in FIG. 2), the pin 18 is pushed out from the stopper 12 to the second inner ring 4 side.

  The moving means 13 pushes the rod 15 to one axial side (left side in FIG. 2) when the solenoid 14 is on, and retracts the rod 15 to the other axial side (right side in FIG. 2) when the solenoid 14 is off. When the rod 15 moves backward, as shown in FIG. 2, the pin 18 is pushed from the stopper 12 toward the movable plate 17 through the first inner ring 3 and the second inner ring 4 by the biasing force of the disc spring 11.

  When the solenoid 15 is turned off, the rod 15 moves backward, and when the first inner ring 3 and the second inner ring 4 are pushed to the other side in the axial direction (right side in FIG. 2) by the biasing force of the disc spring 11, the second inner ring 4 The second outer raceway surface 4 a is moved in a direction away from the outer peripheral surface of the second roller 7. On the other hand, the first outer circumferential raceway surface 3 a of the first inner ring 3 is pressed against the outer circumferential surface of the first roller 6. In this state, rotational power that causes the first inner ring 3 to rotate in a predetermined direction with respect to the outer ring 5 by the relative rotation of the first inner ring 3 and the outer ring 5 (rotational power that causes the four-wheel drive vehicle 100 to travel forward). When input to the output shaft 103, the first roller 6 rolls on the first outer raceway surface 3 a of the first inner ring 3. The first roller 6 bites into the first inner raceway surface 5a of the outer ring 5 by its traction, locks (engages) with a wedge action, and rotates integrally with the first inner ring 3 and the outer ring 5. As a result, the rotational power input to the output shaft 103 is transmitted from the outer wheel 5 to the gear 5c and transmitted to the front wheel drive system (front wheel differential device 113 and the like). As a result, a four-wheel drive state can be achieved.

  As for the second roller 7, the second outer raceway surface 4 a of the second inner ring 4 is moved away from the outer peripheral surface of the second roller 7. It cannot bite into the raceway surface 5b. Therefore, power transmission via the second roller 7 is interrupted.

  Accordingly, when the rotational speed of the front wheel drive system (front wheel differential device 113, etc.) increases and the rotational speed of the outer ring 5 becomes larger than the rotational speed of the first inner ring 3 (for example, in coasting), the rotational speed. Since the engagement of the first roller 6 is released due to the difference, the transmission of power from the outer ring 5 to the first inner ring 3 is interrupted. Since the rotational power of the output shaft 103 is transmitted to the rear wheel drive system (rear wheel differential device 104 and the like), the four-wheel drive vehicle 100 enters a two-wheel drive (rear wheel drive) state. Similarly, the two-wheel drive (rear wheel drive) state is also established when the output shaft 103 rotates backward in which the rotation direction of the output shaft 103 is opposite to the rotation direction during forward travel.

  When the first roller 6 engages with the first inner ring 3 and the outer ring 5, the first roller 6 rolls slightly by the amount of elastic displacement and is displaced to one axial side (stopper 10 side). At the same time, the outer ring 5 is also displaced to one axial side (stopper 10 side). Since the amount of axial movement of the outer ring 5 is restricted by the step 5d of the outer ring 5 abutting against the stopper 10, the outer ring 5 cannot move any further. That is, when an excessive torque (peak torque) that cannot be transmitted unless the outer ring 5 moves in the axial direction beyond the regulated axial movement amount is input to the output shaft 103, the first roller 6 The first outer peripheral raceway surface 3a and the first inner peripheral raceway surface 5a cannot be engaged. Accordingly, it is possible to prevent the peak torque from being transmitted to the front wheel drive system, so that it is not necessary to design the structure of the front wheel drive system in consideration of the peak torque, and the front wheel drive system can be reduced in size and weight.

  Next, the operation of the clutch 2 when the solenoid 14 is turned on and the rod 15 is pushed in will be described with reference to FIG. FIG. 3 is an axial cross-sectional view of the clutch 2 after the traveling mode is switched. As shown in FIG. 3, when the solenoid 14 is turned on and the rod 15 is pushed out, the moving plate 17 is moved toward the stopper 12 and pushes the pin 18. As a result, the first inner ring 3 and the second inner ring 4 are pushed back toward the stopper 10 against the biasing force of the disc spring 11, and the first outer raceway surface 3 a of the first inner ring 3 extends from the outer circumference of the first roller 6. Moved away. On the other hand, the second outer peripheral raceway surface 4a of the second inner ring 4 is pressed against the outer peripheral surface of the second roller 7, and accordingly, the outer peripheral surface of the second roller 7 is pressed against the second inner peripheral raceway surface 5b.

  When the four-wheel drive vehicle 100 travels forward, the first roller 6 cannot be engaged with the first inner ring 3 and the outer ring 5, so the power of the output shaft 103 is not transmitted to the front wheel drive system via the clutch 2. Accordingly, the four-wheel drive vehicle 100 is in a two-wheel drive (rear wheel drive) state. On the other hand, during coasting, the outer ring 5 rotates in a predetermined direction with respect to the second inner ring 4 due to the relative rotation between the second inner ring 4 and the outer ring 5. Due to the difference in rotational speed, the second roller 7 rolls on the second inner circumferential raceway surface 5 b of the outer ring 5. The second roller 7 bites into the second outer raceway surface 4a of the second inner ring 4 by its traction, locks (engages) with a wedge action, and rotates integrally with the second inner ring 4 and the outer ring 5. As a result, the rotational power input to the outer ring 5 is transmitted to the output shaft 103 (engine 101) via the second inner ring 4, so that a braking action is obtained while traveling in a four-wheel drive state.

  During reverse travel, the rotation direction of the output shaft 103 is opposite to that of forward travel, so that the output shaft 103 (second inner ring 4) is relative to the outer ring 5 due to relative rotation between the second inner ring 4 and the outer ring 5. Rotate in the opposite direction as in forward travel. Then, the second roller 7 rolls on the second outer raceway surface 4 a of the second inner ring 4. The second roller 7 bites into the second inner circumferential raceway surface 5b of the outer ring 5 by its traction, locks (engages) with a wedge action, and rotates integrally with the second inner ring 4 and the outer ring 5. Thereby, the rotational power input to the output shaft 103 is transmitted from the outer wheel 5 to the gear 5c and transmitted to the front wheel drive system (front wheel differential device 113 and the like). As a result, the four-wheel drive vehicle 100 travels backward in a four-wheel drive state. As described above, the clutch 2 can be switched to two travel modes.

  Next, the axial force (thrust) acting on the gear 5c provided on the outer ring 5 moving in the axial direction will be described with reference to FIG. FIG. 4 is a schematic diagram showing the meshing of the gear 5c. In FIG. 4, the gear 5 c and the driven gear 112 that engages with the gear 5 c are illustrated, illustration of other parts of the clutch 2 is omitted, and some of the teeth 5 c 1 and 112 a formed on the gear 5 c and the driven gear 112, respectively. The illustration is omitted.

  FIG. 4 shows a state in which the rotational power is input from the output shaft 103 to the clutch 2 and the gear 5c rotates in the direction of the arrow Ro and the four-wheel drive vehicle 100 (see FIG. 1) travels forward (shown in FIG. 2). State). The gear 5c is formed with teeth 5c1 whose teeth are non-parallel to the axis O, and in this embodiment, the gear 5c is constituted by a helical gear. The driven gear 112 that meshes with the gear 5c is also constituted by a helical gear in which teeth 112a whose teeth are non-parallel to the axis O are formed.

  When the rotation is transmitted to the driven gear 112 (the rotation direction is the arrow Rt direction) by the power transmitted from the output shaft 103 to the gear 5c (the rotation direction is the arrow Ro direction), the gear 5c and the driven gear 112 are respectively constant. An axial force (thrust force) in the direction (the arrow A direction and the arrow P direction in FIG. 4) is generated. The direction of the tooth trace of the gear 5c and the driven gear 112 is such that the direction of the axial force acting on the gear 5c (the direction of arrow A in FIG. 4) is the first outer raceway surface 3a and the first inner raceway surface 5a (see FIG. 2). ) Is set to be the same as the moving direction of the outer ring 5 in the axial direction when the first roller 6 is engaged (the direction of arrow A in FIG. 4).

  Here, the axial component of the frictional force generated on the first outer raceway surface 3a and the first inner raceway surface 5a and the first roller 5 is applied to the first outer raceway surface 3a and the first inner raceway surface 5a. The pulling force in the axial direction of the first inner ring 3 and the outer ring 5 when the one roller 6 is engaged is suppressed, and a predetermined torque cannot be transmitted from the first inner ring 3 to the outer ring 5. On the other hand, according to the clutch 2, in addition to the pulling force of the first outer peripheral raceway surface 3a and the first inner peripheral raceway surface 5a due to rolling of the first roller 6, the outer ring is caused by the axial force due to the reaction force of the driven gear 112. 5 is promoted to move in the axial direction. As a result, since the pulling force in the axial direction of the first inner ring 3 and the outer ring 5 can be increased, the clutch 2 can reliably transmit a predetermined torque.

  On the other hand, when the rotational speed of the front wheel drive system (front wheel differential device 113 or the like) becomes higher than the rotational speed of the rear wheel drive system (rear wheel differential device 104 or the like), the driven gear 112 is driven and the gear 5c is driven. Become. In this case, axial forces in opposite directions (in the opposite direction of arrow A and the opposite direction of arrow P in FIG. 4) are generated in the gear 5c and the driven gear 112, respectively. This axial force acts on the outer ring 5 faster than the pulling force of the first inner ring 3 and the outer ring 5 due to the rotation of the first roller 6 because the driven gear 112 acts on the driving side and the gear 5c on the driven side. As a result, the engagement between the first outer raceway surface 3a and the first inner raceway surface 5a and the first roller 6 can be quickly performed.

  In the case where the gear 5c and the driven gear 112 are constituted by spur gears, when the outer ring 5 moves in the axial direction, the tooth surfaces rub against each other and a frictional force parallel to the axis O is generated. This frictional force suppresses the pulling force in the axial direction of the first inner ring 3 and the outer ring 5 when the first roller 6 is engaged with the first outer peripheral raceway surface 3a and the first inner peripheral raceway surface 5a. Cause inability to move smoothly. On the other hand, the clutch 2 makes the tooth streaks of the gear 5c non-parallel to the axis O, thereby generating axial thrust and promoting the axial movement of the outer ring 5. Further, since it is not necessary to increase the distance between the tooth surfaces of the gear 5c and the driven gear 112 in order to reduce the frictional force in the axial direction, rattling between the gear 5c and the driven gear 112 can be suppressed.

  Further, since the gear 5c and the driven gear 112 are constituted by helical gears, the strength can be increased as compared with a spur gear of the same size, and rotational power can be transmitted quietly. Further, high-speed rotation can be transmitted, and the combination of the number of teeth of the gear 5c and the driven gear 112 is not limited, and the flexibility is excellent.

  Next, referring to FIG. 4, the friction between the tooth surfaces of the gear 5c and the driven gear 112 will be examined. When the gear 5c is rotated in one direction (the direction of the arrow Ro in FIG. 4), the circumferential force N in the plane perpendicular to the axis acts on the tooth surface of the gear 5c by the reaction force of the driven gear 112. On the other hand, the circumferential force N in the plane perpendicular to the axis also acts on the tooth surface of the driven gear 112. The circumferential force N is decomposed into a tangential force F perpendicular to the axis O and an axial force S parallel to the axis O. If the torsion angle of the gear 5c is β, the axial force S is expressed by equation (1).

S = N · sin β Formula (1)
Further, if the friction coefficient between the tooth surfaces of the gear 5c and the driven gear 112 is μ, the axial component force S ′ of the frictional force caused by the tooth surfaces of the drive gear 8b is expressed by Expression (2).

S ′ = μN · cos β Formula (2)
Here, in order to move the outer ring 5 to one side in the axial direction (left side in FIG. 2), it is necessary to move the gear 5c in the axial direction (direction of arrow A in FIG. 4) with respect to the driven gear 112. For this purpose, it is necessary that the absolute value of the axial force S is larger than the absolute value of the axial component S ′ of the frictional force, that is, the expression (3) must be established. Since S> 0 and S ′> 0, the absolute value symbol is omitted in Equation (3).

S-S '> 0 ... Formula (3)
When the equations (1) and (2) are substituted into the equation (3) and solved, the equation (4) is derived.

μ <tan β Formula (4)
If the coefficient of friction μ between the tooth surfaces of the gear 5c and the driven gear 112 and the torsion angle β of the gear 5c are set as shown in the equation (4), the gear 5c is moved in the axial direction with respect to the driven gear 112 (see FIG. A direction). Accordingly, the outer ring 5 can be moved in the axial direction (arrow A direction in FIG. 4), so that the axial pulling force of the first inner ring 3 and the outer ring 5 is caused by friction between the tooth surfaces of the gear 5c and the driven gear 112. It can be prevented from being suppressed. As a result, the clutch 2 can reliably transmit a predetermined torque.

  Next, a second embodiment will be described with reference to FIGS. In the first embodiment, the clutch 2 has been described in which the first inner ring 3 and the second inner ring 4 are collectively moved in the axial direction by the solenoid 14 that reciprocates in the axial direction. On the other hand, in the second embodiment, a description will be given of the clutch 22 that can rotate the two end cams 31 and 32 by the motor 30 and separately move the first inner ring 23 and the second inner ring 24 in the axial direction.

  The clutch 22 is mounted on the four-wheel drive vehicle 100 described in the first embodiment in place of the clutch 2 (the same applies to other embodiments). The same parts as those in the first embodiment are denoted by the same reference numerals, and the following description is omitted. FIG. 5 is a sectional view in the axial direction of the clutch 22 of the power transmission device 1 in the second embodiment, FIG. 6 is a sectional view in the axial direction of the clutch 22 after switching the traveling mode, and FIG. FIG. 7B is an axial sectional view of the clutch 22 after switching, and FIG. 7B is an axial sectional view of the clutch 22 after switching to another traveling mode.

  As shown in FIG. 5, the clutch 22 is arranged in parallel with the first inner ring 23 disposed on the radially outer side of the output shaft 103 and the axial direction of the first inner ring 23 and disposed on the radially outer side of the output shaft 103. The second inner ring 24 provided, the outer ring 5 disposed radially outside the first inner ring 23 and the second inner ring 24, and the outer ring 5, the first inner ring 23 and the second inner ring 24 are interposed. A plurality of first rollers 6 and second rollers 7, and a first holder 8 and a second holder 9 that hold the first roller 6 and the second roller 7, respectively.

  The first inner ring 23 is an annular member having a function of transmitting rotational power, and the first inner ring 23 described in the first embodiment is formed except that a through hole 23a penetrating in the axial direction is formed. Since the configuration is the same as that of the inner ring 3, the following description is omitted. In the output shaft 103, a disk-like stopper 25 extending radially outward from the outer peripheral surface is erected on one axial side of the first inner ring 23 (left side in FIG. 5), and at a position corresponding to the through hole 23a. A hole 25a penetrating in the axial direction is formed. A coil spring 26 (elastic member) is disposed between the stopper 25 and one axial end of the first inner ring 23. As a result, the first inner ring 23 is urged toward the other axial side (the right side in FIG. 5) with respect to the stopper 25.

  The second inner ring 24 is an annular member having a function of transmitting rotational power, and the second inner ring 24 described in the first embodiment is formed except that a through hole 24a penetrating in the axial direction is formed. Since the configuration is the same as that of the inner ring 4, the following description is omitted. In the output shaft 103, a disk-shaped stopper 27 extending from the outer peripheral surface toward the radially outer side is erected on the other axial side of the second inner ring 24 (right side in FIG. 5), and at a position corresponding to the through hole 24a. A hole 27a penetrating in the axial direction is formed. A coil spring 28 (elastic member) is disposed between the stopper 27 and the other axial end of the second inner ring 24. As a result, the second inner ring 24 is urged toward the axial direction one side (the left side in FIG. 5) with respect to the stopper 27.

  The moving means 29 is a means for moving the first inner ring 23 and the second inner ring 24 in the axial direction in conjunction with each other. The motor 30 is arranged to be separated from the stopper 27 in the axial direction, and the rotation of the motor 30 is performed. And pins 37 and 41 which appear and disappear. The motor 30 is a device that rotates the end face cams 31 and 32 that are respectively arranged on the outer sides in the axial direction of the stoppers 25 and 27. The guide rail 33 is a shaft-like member arranged in parallel with the output shaft 103, and guide portions 34 and 38 configured to be slidable along the guide rail 33 are positioned at the axially outer positions of the stoppers 25 and 27. It is installed. Guide pins 34a, 38a project from the guide portions 34, 38, and the guide portions 34, 38 are in contact with the cam surfaces 31a, 32a of the end cams 31, 32, respectively. Each is biased outward in the axial direction.

  Arms 35 and 39 extending from the guide portions 34 and 38 toward the output shaft 103 are provided on the guide portions 34 and 38, respectively. The moving plates 36 and 40 are annular members in which the distal ends of the arms 35 and 39 are linked. The output shaft 103 penetrates the moving plates 36 and 40 so that the moving plates 36 and 40 can move in the axial direction as the arms 35 and 39 reciprocate in the axial direction. Composed. Further, the moving plates 36 and 40 are arranged so that one end surfaces thereof are in contact with one end in the axial direction of the pins 37 and 41 inserted loosely into the hole portions 25a and 27a of the stoppers 25 and 27 and the through holes 23a and 24a. The pins 37 and 41 are set to have axial lengths in which one end in the axial direction is pushed by the moving plates 36 and 40 and the other end can be brought into contact with the axial end surfaces of the first inner ring 23 and the second inner ring 24. . Therefore, when the moving plates 36 and 40 move to the stoppers 27 and 25, respectively, the pins 37 and 41 are pushed out in the axial direction, and the first inner ring 23 and the second inner ring 24 are subjected to the urging force of the coil springs 26 and 28. Move in the axial direction against each other.

  As described above, the moving means 29 moves in accordance with the rotation angle of the motor 30 by driving the guide portions 34 and 38 and the arms 35 and 39 (followers) by the cam surfaces 31 a and 32 a of the end cams 31 and 32. The plates 36 and 40 are moved in the axial direction. The length by which the pins 47 and 41 are pushed out changes depending on the position of the moving plates 36 and 40, and the first inner ring 23 and the second inner ring 24 take four positions with different axial positions (FIGS. 5, 6, and 7). a) and FIG. 7B).

  In the position shown in FIG. 5, the movable plates 36 and 40 are positioned away from the stoppers 25 and 27 by the cam surfaces 31 a and 32 a. As a result, the first inner ring 23 and the second inner ring 24 are biased inward in the axial direction by the coil springs 26, 28, and the first outer raceway surface 3 a of the first inner ring 23 and the second outer raceway surface 4 a of the second inner ring 24. Are pressed against the outer peripheral surfaces of the first roller 6 and the second roller 7, respectively. In this position, rotational power that causes the first inner ring 23 to rotate in a predetermined direction with respect to the outer ring 5 by the relative rotation of the first inner ring 23 and the outer ring 5 (rotational power that causes the four-wheel drive vehicle 100 to travel forward). When input to the output shaft 103, the first roller 6 rolls on the first outer raceway surface 3a of the first inner ring 23, bites into the first inner raceway surface 5a of the outer ring 5 by its traction, and locks by the wedge action ( Engaging) and rotating integrally with the first inner ring 23 and the outer ring 5. Thereby, the rotational power input to the output shaft 103 is transmitted from the outer wheel 5 to the gear 5c and transmitted to the front wheel drive system (front wheel differential device 113 and the like).

  During coasting, the outer ring 5 rotates in a predetermined direction with respect to the second inner ring 24 due to the relative rotation between the second inner ring 24 and the outer ring 5, and therefore the rotation between the second inner ring 24 and the outer ring 5 is performed. Due to the speed difference, the second roller 7 rolls on the second inner circumferential raceway surface 5 b of the outer ring 5. The second roller 7 bites into the second outer raceway surface 4a of the second inner ring 24 by its traction, locks (engages) with a wedge action, and rotates integrally with the second inner ring 24 and the outer ring 5. As a result, the rotational power input to the outer ring 5 is transmitted to the output shaft 103 (engine 101) via the second inner ring 4, so that a braking action is obtained. Similarly, during reverse running, the second roller 7 bites into the second inner circumferential raceway surface 5 b of the outer ring 5 and rotates together with the second inner ring 24 and the outer ring 5. Thereby, the rotational power input to the output shaft 103 is transmitted from the outer wheel 5 to the gear 5c and transmitted to the front wheel drive system (front wheel differential device 113 and the like). Therefore, at the position of the clutch 22, the four-wheel drive vehicle 100 can always travel in the four-wheel drive state.

  In the position shown in FIG. 6, the moving plate 40 is positioned close to the stopper 25 by the cam surfaces 31 a and 32 a, and the moving plate 36 is positioned away from the stopper 27. At this time, the first inner ring 23 is biased to the other axial side (right side in FIG. 6) by the coil spring 26, while the other axial side (right side in FIG. 6) is biased by the pin 41 against the biasing force of the coil spring 28. ) Is pressed against the second inner ring 24. As a result, the first outer raceway surface 3 a of the first inner ring 23 is pressed against the outer circumference surface of the first roller 6, and the second outer raceway surface 4 a of the second inner ring 24 is separated from the outer circumference surface of the second roller 7. In this case, when rotational power that causes the four-wheel drive vehicle 100 to travel forward is input to the output shaft 103, the first roller 6 is locked (engaged) and rotates integrally with the first inner ring 23 and the outer ring 5. Driven. On the other hand, since the second roller 7 is in a free state with respect to the second inner wheel 24 and the outer wheel 5, it is in a two-wheel drive (rear wheel drive) state during coasting travel and reverse travel.

  In the position shown in FIG. 7A, the movable plates 36 and 40 are brought close to the stoppers 27 and 25 by the cam surfaces 31a and 32a. At this time, the first inner ring 23 and the second inner ring 24 are pressed outward in the axial direction by the pins 37 and 41 against the urging force of the coil springs 26 and 28. As a result, the first outer raceway surface 3 a of the first inner ring 23 and the second outer raceway surface 4 a of the second inner ring 24 are separated from the outer circumference surfaces of the first roller 6 and the second roller 7. Since the first roller 6 and the second roller 7 are in a free state with respect to the first inner ring 23, the second inner ring 24, and the outer ring 5, the four-wheel drive vehicle 100 is always in a two-wheel drive (rear wheel drive) state. .

  By disconnecting the intermittent device 116 (see FIG. 1) in the two-wheel drive state, the rotation of the gears on the right front wheel first drive shaft 115 side of the right front wheel first drive shaft 115 and the front wheel differential device 113 is stopped. Therefore, it is possible to prevent the fuel consumption from being reduced due to the friction loss. Thereby, at the time of forward running, fuel consumption can be suppressed by cutting the intermittent device 116 while setting the two-wheel drive state by the position shown in FIG.

  In order to change from this state (the state where the interrupting device 116 is disconnected) to the four-wheel drive state (forward travel), first, the clutch 22 is set to the position shown in FIG. As a result, the first roller 6 can be engaged with the first inner ring 23 and the outer ring 5, the first roller 6 bites into the first inner ring 23 and the outer ring 5 by the power of the output shaft 103, and the outer ring 5 integrally with the output shaft 103. Rotates. Since the rotational speed of the driven gear 112 and the front drive shaft 111 engaged with the gear 5c and the rotational speed of the front wheel drive system (particularly the right front wheel first drive shaft 115) can be increased, the right front wheel first drive shaft 115 and the right The rotation speed of the front wheel second drive shaft 117 is detected by a detection device (not shown), and when the rotation speeds coincide with each other or when the difference between the rotation speeds falls within a predetermined range, the intermittent device 116. Connect. Thereby, it is possible to suppress a shock when connecting the intermittent device 116 and smoothly switch from the two-wheel drive state to the four-wheel drive state.

  In the position shown in FIG. 7B, the moving plate 36 is positioned close to the stopper 27 by the cam surfaces 31 a and 32 a, and the moving plate 40 is positioned away from the stopper 25. At this time, the second inner ring 24 is urged to one side in the axial direction (left side in FIG. 7B) by the coil spring 28, while the pin 37 opposes the urging force of the coil spring 26 to the outside in the axial direction. One inner ring 23 is pressed. As a result, the second outer raceway surface 4 a of the second inner ring 24 is pressed against the outer circumference surface of the second roller 7, and the first outer raceway surface 3 a of the first inner ring 23 is separated from the outer circumference surface of the first roller 6. In this case, when the rotational power that causes the four-wheel drive vehicle 100 to travel forward is input to the output shaft 103, the first roller 6 is in a free state with respect to the first inner wheel 23 and the outer wheel 5. (Rear wheel drive) state.

  On the other hand, during coasting traveling or reverse traveling, the second roller 7 is locked (engaged) and rotates integrally with the second inner ring 24 and the outer ring 5, so that a four-wheel drive state is established. As described above, in the second embodiment, since the first inner ring 23 and the second inner ring 24 can be moved separately by the moving means 29, the range of selection of drive wheels for each travel mode can be expanded. .

  Next, a third embodiment will be described with reference to FIGS. In the first embodiment, the case where the first inner ring 3 and the second inner ring 4 are collectively moved in the axial direction by the solenoid 14 has been described. In contrast, in the third embodiment, a case where the first inner ring 53 and the second inner ring 54 are separately moved in the axial direction by the solenoid 58 will be described. In addition, about the part same as what was demonstrated in 1st Embodiment, the same code | symbol is attached | subjected and the following description is abbreviate | omitted. FIG. 8 is an axial sectional view of the clutch 52 of the power transmission device 1 according to the third embodiment, and FIG. 9A is an axial sectional view of the clutch 52 after the traveling mode is switched, and FIG. It is an axial sectional view of the clutch 52 after switching to another travel mode.

  As shown in FIG. 8, the clutch 52 is arranged in parallel with the first inner ring 53 disposed on the radially outer side of the output shaft 103 and the axial direction of the first inner ring 53 and disposed on the radially outer side of the output shaft 103. The second inner ring 54, the outer ring 5 disposed radially outside the first inner ring 53 and the second inner ring 54, and the outer ring 5, the first inner ring 53 and the second inner ring 54 are interposed. A plurality of first rollers 6 and second rollers 7, and a first holder 8 and a second holder 9 that hold the first roller 6 and the second roller 7, respectively.

  The first inner ring 53 is an annular member that is urged in a direction away from the stopper 10 by the disc spring 11, and a concave portion that locks a coil spring 55 (described later) is formed at an axial end portion. Other than that, the configuration is the same as that of the first inner ring 3 described in the first embodiment. The second inner ring 54 is formed with a through hole 54a penetrating in the axial direction, and a concave portion for locking a coil spring 55 (described later) is formed at an end in the axial direction. Other than that, the configuration is the same as that of the first inner ring 3 and the second inner ring 4 described in the first embodiment, and thus the following description is omitted. Since the second inner ring 54 is provided with a coil spring 55 (elastic member) between the first inner ring 53 and the second inner ring 54, the second inner ring 54 is axially opposite to the first inner ring 53 (the right side in FIG. 8). Be energized by.

  In the output shaft 103, a disk-like stopper 56 extending radially outward from the outer peripheral surface is erected on the other axial side of the second inner ring 54 (right side in FIG. 8). The stopper 56 corresponds to the through hole 54a. A hole portion 56a penetrating in the axial direction is formed at a position to be formed. The stopper 56 has a hole 56b penetrating in the axial direction at a position different from the hole 56a. A pin 60 is inserted through the through hole 54a and the hole 56a, and a pin 61 is inserted through the hole 56b.

  The moving means 57 is a means for moving the first inner ring 53 and the second inner ring 54 in the axial direction in conjunction with each other. The solenoid 58 arranged in the axial direction away from the stopper 56 and the solenoid 58 are operated. It is provided with pins 60 and 61 that appear and disappear. When the solenoid 58 is off, the rod 59 extending toward the stopper 56 is retracted, and the pushing length of the rod 59 when it is on can be adjusted in two stages. The tip of the rod 59 is brought into contact with the other side of the arm 16 disposed between the solenoid 58 and the stopper 56 and having one end 16a pivotally supported.

  The moving plate 17 that is moved in the axial direction by the reciprocating rotation of the arm 16 is disposed so that one end surface thereof can be brought into contact with the axial end surfaces of the pins 60 and 61 penetrating the stopper 56. The pins 60 and 61 are set to have axial lengths such that one end in the axial direction is pushed by the movable plate 17 and the other ends can be brought into contact with the axial end surfaces of the first inner ring 53 and the second inner ring 54.

  The pin 61 is set to have an axial length that does not contact the moving plate 17 when the solenoid 58 is off (see FIG. 8). When the rod 58 is pushed out to the maximum by operating the solenoid 58 (see FIG. 9A), the pins 60 and 61 are pushed out in the axial direction, and the first inner ring 53 and the second inner ring 54 are made of the disc spring 11 and the coil. Each of them moves in the axial direction against the urging force of the spring 55. When the rod 59 is pushed out to the intermediate position by the operation of the solenoid 58 (see FIG. 9B), the pin 60 is pushed in the axial direction, and the first inner ring 53 is pivoted against the urging force of the disc spring 11. Move in the direction. Therefore, in the moving means 57, the moving plate 17 is moved in the axial direction in accordance with the pushing length of the rod 59 by the solenoid 58. The length by which the pins 60 and 61 are pushed out changes depending on the position of the moving plate 17, and the first inner ring 53 and the second inner ring 54 take three positions having different axial positions (FIGS. 8, 9A and 9). (B)).

  In the position shown in FIG. 8 (the retracted position of the rod 59), the first inner ring 53 and the second inner ring 54 are urged toward the other side in the axial direction (right side in FIG. 8) by the disc spring 11 and the coil spring 55. At this time, the first outer raceway surface 3 a of the first inner ring 53 is pressed against the outer circumference surface of the first roller 6, while the second outer raceway surface 4 a of the second inner ring 54 is separated from the outer circumference surface of the second roller 7. In this case, when rotational power that causes the four-wheel drive vehicle 100 to travel forward is input to the output shaft 103, the first roller 6 is locked (engaged) and rotates integrally with the first inner ring 53 and the outer ring 5. Driven. On the other hand, since the second roller 7 is in a free state with respect to the second inner ring 54 and the outer ring 5, it is in a two-wheel drive (rear wheel drive) state during coasting and reverse travel.

  In the position shown in FIG. 9A (the maximum pushing position of the rod 59), the pins 60 and 61 are opposed to one side in the axial direction (left side in FIG. 9A) against the biasing force of the disc spring 11 and the coil spring 55. The first inner ring 53 and the second inner ring 54 are pressed. At this time, the second outer raceway surface 4 a of the second inner ring 54 is pressed against the outer circumference surface of the second roller 7, while the first outer raceway surface 3 a of the first inner ring 53 is separated from the outer circumference surface of the first roller 6. In this case, when the rotational power that causes the four-wheel drive vehicle 100 to travel forward is input to the output shaft 103, the first roller 6 is in a free state with respect to the first inner wheel 52 and the outer wheel 5. (Rear wheel drive) state. On the other hand, during coasting travel and reverse travel, the second roller 7 is locked (engaged) and rotates integrally with the second inner ring 54 and the outer ring 5, so that a four-wheel drive state is established.

  In the position shown in FIG. 9B (intermediate position of the rod 59), the first inner ring 53 is pressed against one side in the axial direction (left side in FIG. 9B) by the pin 60 against the biasing force of the disc spring 11. The second inner ring 54 is urged by the coil spring 55 toward the other side in the axial direction (the right side in FIG. 9B). At this time, the first outer raceway surface 3 a of the first inner ring 53 and the second outer raceway surface 4 a of the second inner ring 54 are separated from the outer peripheral surfaces of the first roller 6 and the second roller 7. Since the first roller 6 and the second roller 7 are in a free state with respect to the first inner ring 53, the second inner ring 54, and the outer ring 5, the four-wheel drive vehicle 100 is always in a two-wheel drive (rear wheel drive) state. . As described above, in the third embodiment, the first inner ring 53 and the second inner ring 54 can be moved separately by the simple moving means 57 using the solenoid 58. The range of selection can be expanded and the apparatus can be simplified.

  Next, a fourth embodiment will be described with reference to FIGS. In the third embodiment, the clutch 52 that can take a position where either the first roller 6 or the second roller 7 is free using the solenoid 58 has been described. In contrast, in the fourth embodiment, a clutch 62 that can take a position where both the first roller 6 and the second roller 7 are locked using a solenoid 58 will be described. In addition, about the part same as 1st Embodiment to 3rd Embodiment, the same code | symbol is attached | subjected and the following description is abbreviate | omitted. FIG. 10 is an axial sectional view of the clutch 62 in the fourth embodiment, FIG. 11 (a) is an axial sectional view of the clutch 62 after switching the traveling mode, and FIG. 11 (b) is another traveling mode. It is an axial sectional view of the clutch 62 after switching to.

  As shown in FIG. 10, the clutch 62 is arranged in parallel with the first inner ring 63 disposed on the radially outer side of the output shaft 103 and the axial direction of the first inner ring 63 and is disposed on the radially outer side of the output shaft 103. A second inner ring 64 provided; an outer ring 65 disposed radially outside the first inner ring 63 and the second inner ring 64; and an outer ring 65 interposed between the first inner ring 63 and the second inner ring 64. A plurality of first rollers 66 and second rollers 67, and a first holder 68 and a second holder 69 for holding the first roller 66 and the second roller 67, respectively.

  Each of the first inner ring 63 and the second inner ring 64 is an annular member, and a first outer circumferential raceway surface 63a and a second outer circumferential raceway surface 64a that form a single leaf rotation hyperboloid around the axis O are formed on the outer circumferential surface. ing. The first inner ring 63 and the second inner ring 64 are restricted from rotating with respect to the output shaft 103 by splines, and are allowed to move in the axial direction with respect to the output shaft 103.

  The outer ring 65 is an annular member disposed on the radially outer side of the first inner ring 63 and the second inner ring 64, and has a first inner circumferential raceway surface 65 a and a second one that form a single leaf rotation hyperboloid around the axis O. Inner circumferential raceway surfaces 65b are respectively formed on inner circumferential surfaces facing the first outer circumferential raceway surface 63a and the second outer circumferential raceway surface 64a, and a sprocket 65c is provided on the outer circumferential surface. The sprocket 65c is a part where the chain 73 is engaged with a sprocket (not shown) formed in place of the driven gear 112 provided on the front drive shaft 111 (see FIG. 1). Power is transmitted between the outer ring 65 and the front drive shaft 111 via the chain 73.

  The first roller 66 is a member formed in a cylindrical shape, and is inclined by a certain angle from the surface including the axis O by the first cage 68 (set to a constant skew angle with respect to the axis O). A plurality of first outer peripheral raceway surfaces 63a and first inner peripheral raceway surfaces 65a are arranged in the circumferential direction. The second roller 67 is a member formed in a cylindrical shape, and is inclined at a certain angle in a direction opposite to the first roller 63 from the surface including the axis O by the second cage 99 (constant with respect to the axis O). A plurality of second outer circumferential raceway surfaces 64a and second inner circumferential raceway surfaces 65b are arranged in the circumferential direction. The first roller 66 is engaged with the first outer raceway surface 63a and the first inner circumference raceway surface 65a to transmit power, and the second outer raceway surface 64a and the second inner circumference raceway surface 65b are supplied with the second roller. Power is transmitted by the engagement of 67.

  The outer ring 65 is configured to be rotatable relative to the first inner ring 63 and the second inner ring 64 and to be relatively movable in the axial direction, and is formed in a step shape on the radially inner side on the other side in the axial direction (right side in FIG. 10). When the stepped portion 65e abuts against the axial end surface on the radially outer side of the stopper 72 provided immovably with respect to the output shaft 103, further movement of the outer ring 65 to the other side in the axial direction is restricted. Further, the wall portion 65d formed integrally with the outer ring 65 abuts against the flange portion 103a provided on one side (left side in FIG. 10) of the output shaft 103, so that one axial side of the outer ring 65 is further increased. Movement to is regulated. The stopper 72 and the stepped portion 65e stop the axial movement of the outer ring 65 at a fixed position when the first roller 66 is engaged and screwed into the first outer circumferential raceway surface 63a and the first inner circumferential raceway surface 65a. And a function of a torque limiter that prevents a torque exceeding a certain level from being applied, and a function of preventing the first roller 66 and the second roller 67 from slipping out.

  The outer ring 65 configured to be movable in the axial direction is linked to the front drive shaft 111 by a chain 73. Since the chain 73 is stretched in a direction orthogonal to the axis O, the chain 73 has flexibility in the direction of the axis O. Therefore, the chain 73 can follow the displacement of the outer ring 65 in the axial direction, and the chain 73 can prevent the movement of the outer ring 65 from moving in the axial direction.

  A disc spring 70 is inserted between the wall 65 d of the outer ring 5 and the first inner ring 63, and a disc spring 71 is inserted between the first inner ring 63 and the second inner ring 64. A pin 75 is inserted through a hole 72 a formed through the stopper 72 in the axial direction. The axial positions of the first inner ring 63 and the second inner ring 64 can be determined by the protruding length of the pin 75 from the stopper 72 and the biasing force of the disc springs 70 and 71. The urging force of the disc spring 71 is set larger than the urging force of the disc spring 70.

  The moving means 74 is a means for moving the first inner ring 63 and the second inner ring 64 in the axial direction in conjunction with a pin 75 that moves in and out in conjunction with the reciprocating movement of the solenoid 58. Since the solenoid 58 can switch the extrusion length of the rod 59 in two stages, the extrusion length of the pin 75 can be changed depending on the position of the moving plate 17. As a result, the first inner ring 63 and the second inner ring 64 take three positions with different axial positions (FIGS. 10, 11A, and 11B).

  In the position shown in FIG. 10 (the retracted position of the rod 59), the first inner ring 63 and the second inner ring 64 are urged toward the other side in the axial direction (right side in FIG. 10) by the disc springs 70 and 71. At this time, the first outer raceway surface 3 a of the first inner ring 63 and the second outer raceway surface 4 a of the second inner ring 64 are separated from the outer circumference surfaces of the first roller 66 and the second roller 67. Since the first roller 66 and the second roller 67 are in a free state with respect to the first inner ring 63, the second inner ring 64, and the outer ring 65, the four-wheel drive vehicle 100 is always in a two-wheel drive (rear wheel drive) state. .

  In the position shown in FIG. 11A (maximum push-out position of the rod 59), the second inner ring 64 is axially moved to one side (left side in FIG. 11A) by the pin 75 against the biasing force of the disc springs 70 and 71. Is moved, and the first inner ring 63 is moved by the biasing force of the disc spring 71. At this time, the first outer raceway surface 63 a of the first inner ring 63 and the second outer raceway surface 64 a of the second inner ring 64 are pressed against the outer circumference surfaces of the first roller 66 and the second roller 67. In this case, the four-wheel drive vehicle 100 is in a four-wheel drive state during forward travel, coasting travel, and reverse travel.

  At the position shown in FIG. 11B (intermediate position of the rod 59), the second inner ring 64 is pushed to the other side in the axial direction (right side in FIG. 11B) by the biasing force of the disc spring 71, and one side in the axial direction. The first inner ring 63 is pushed (left side in FIG. 11A). At this time, the first outer raceway surface 63 a of the first inner ring 63 is pressed against the outer circumference surface of the first roller 66, while the second outer raceway surface 64 a of the second inner ring 64 is separated from the outer circumference surface of the second roller 67. In this case, when the rotational power that causes the four-wheel drive vehicle 100 to travel forward is input to the output shaft 103, the first roller 66 is locked (engaged) to enter the four-wheel drive state. On the other hand, since the second roller 67 is in a free state with respect to the second inner ring 64 and the outer ring 65, it is in a two-wheel drive (rear wheel drive) state during coasting travel and reverse travel. Since the urging force of the disc spring 71 is set larger than the urging force of the disc spring 70, the engagement of the second roller 67 can be released by the urging force of the disc spring 71 with the first roller 66 engaged.

  As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily guessed.

  In each of the embodiments described above, the four-wheel drive vehicle 100 using the engine 101 as a drive source has been described. However, the present invention is not limited to this. For example, a four-wheel drive vehicle and a motor using the engine and motor as drive sources are used. Of course, it can be applied to a four-wheel drive vehicle or the like as a drive source.

  In the above embodiments, the power of the output shaft 103 is transmitted to the first inner rings 3, 23, 53, 63 and the second inner rings 4, 24, 54, 64, and the power is transmitted from the outer rings 5, 65 to the front wheel drive system. However, the present invention is not necessarily limited to this. It is of course possible to provide a connecting portion extending radially inward from the outer rings 5 and 65 and connect the connecting portion to the output shaft 103 while providing an inner ring between the output shaft 103 and the outer ring. . In that case, the axial end surface of the inner ring extends in the axial direction, an extending portion extending axially outward from the axial end surface of the outer ring is provided, and a gear and a sprocket are provided on the outer peripheral surface of the extending portion. Thereby, although the axial direction length becomes large, the effect similar to this Embodiment is realizable.

  In each of the above-described embodiments, the inner ring is divided into two in the axial direction as the first inner rings 3, 23, 53, 63 and the second inner rings 4, 24, 54, 64, and the outer ring 5 positioned on the radially outer side thereof. , 65 are described as being integrated without being divided in the axial direction, but are not necessarily limited thereto. (1) The outer rings 5 and 65 are divided into two in the axial direction to be a first outer ring and a second outer ring, and the inner rings positioned on the inner side in the radial direction are integrated without being divided in the axial direction, (2) the inner ring The first inner ring, the second inner ring, the first outer ring, and the second outer ring are provided by dividing both the outer ring and the outer ring into two in the axial direction, the first outer ring is disposed on the radially outer side of the first inner ring, and the second inner ring Of course, it is possible to employ a configuration in which the second outer ring is arranged on the outer side in the radial direction. In these cases as well, the same effects as the present embodiment can be realized.

  In each of the above embodiments, the case where the outer rings 5 and 65 are integrated without being divided in the axial direction has been described. Therefore, the single gear 5c or the sprocket 65c that engages the driven gear 112 or the chain 73 is provided. However, it is not necessarily limited to this. For example, when the outer rings 5 and 65 are divided into two in the axial direction as the first outer ring and the second outer ring, it is necessary to provide a gear or a sprocket on each of the first outer ring and the second outer ring. This is because power is transmitted between each of the first outer ring and the second outer ring and the front drive shaft 111. However, even when the outer rings 5 and 65 are divided into two in the axial direction to form the first outer ring and the second outer ring, the first outer ring and the second outer ring are connected to rotate integrally. If there is, a gear or a sprocket can be provided on one of the first outer ring and the second outer ring.

  In each said embodiment, 1st outer periphery track surface 3a, 63a, 2nd outer periphery track surface 4a, 64a (outer periphery track surface), 1st inner periphery track surface 5a, 65a, 2nd inner periphery track surface 5b, 65b ( The case where the inner circumferential raceway surface) is formed of a single-leaf rotating hyperboloid and the cylindrical first rollers 6, 66 and the second rollers 7, 67 (rollers) are employed has been described. However, the present invention is not necessarily limited thereto. Of course, it is possible to employ the outer peripheral raceway surface, the inner peripheral raceway surface and the rollers in other forms. Other forms include, for example, an outer peripheral raceway surface and an inner peripheral raceway surface formed of a single-leaf rotating hyperboloid and a roller having a conical shape, an outer peripheral raceway surface and an inner peripheral raceway surface having a conical surface, and an outer peripheral raceway surface. Alternatively, the inner peripheral raceway surface may be cylindrical, or the roller may be drum-shaped, drum-shaped, or cylindrical.

  In addition, it is desirable to form the inner peripheral raceway surface and the outer peripheral raceway surface as a single-leaf rotating hyperboloid or a conical surface in line contact with the outer peripheral surface of the roller. This is because the inner circumferential raceway surface and the outer circumferential raceway surface can be easily processed by making the raceway surface into a simple conical surface. Moreover, durability can be improved compared with the case where a raceway surface is made into a conical surface by making a raceway surface into a monoplane rotation hyperboloid. That is, when a roller having a skew angle is engaged with a raceway surface (single leaf hyperboloid), the roller and the raceway surface can be brought into line contact even if the roller has a small amount of bending in the axial direction. This is because the contact area can be increased (the line contact length can be increased).

  In the above embodiment, the case where the gear 5c and the driven gear 112 are configured by a pair of helical gears (oblique gears) has been described. However, the present invention is not necessarily limited to this, and the tooth trace is not parallel to the axis O. As long as teeth are formed and axial force (thrust) is generated, other gears can naturally be employed. Examples of other gears include bevel gears and screw gears.

  In each of the above-described embodiments, the case where the spline clutch type intermittence device 116 is provided as the intermittence means provided in the four-wheel drive vehicle 100 has been described. However, the present invention is not limited to this, and other clutch type Of course, it is possible to employ an intermittent device. Examples of other clutch systems include a dog clutch system and a conical friction clutch system.

DESCRIPTION OF SYMBOLS 1 Power transmission device 2,22,52,62 Clutch 3,23,53,63 1st inner ring 3a, 63a 1st outer periphery track surface 4,24,54,64 2nd inner ring 4a, 64a 2nd outer periphery track surface 5, 65 Outer ring (first outer ring, second outer ring)
5a, 65a First inner circumferential raceway surface 5b, 65b Second inner circumferential raceway surface 5c Gear 5c1 Teeth 5d, 5e Stepped part (part of movement restricting means)
6,66 1st roller 7,67 2nd roller 8,68 1st retainer 9,69 2nd retainer 10,12,25,27,56,72 Stopper (part of movement restricting means)
11, 71 Belleville spring (first elastic member)
13, 29, 57, 74 Moving means 14, 58 Solenoid 26 Coil spring (first elastic member)
30 motor 55 coil spring (second elastic member)
65c sprocket 70 disc spring (second elastic member)
73 Chain 100 Four-wheel drive vehicle 101 Engine (drive source)
103 Output shaft 104 Rear wheel differential (part of rear wheel drive system)
105 Left rear wheel drive shaft (part of rear wheel drive system)
106 Right rear wheel drive shaft (part of rear wheel drive system)
112 Driven gear 113 Front wheel differential (part of front wheel drive system)
114 Left front wheel drive shaft (part of front wheel drive system)
115 Right front wheel first drive shaft (part of front wheel drive system)
116 Interrupting device (intermittent means)
117 Right front wheel second drive shaft (part of front wheel drive system)
O axis

Claims (7)

A power transmission device for a four-wheel drive vehicle comprising a clutch that transmits power from a drive source to a rear wheel drive system via an output shaft, while transmitting the power of the output shaft to a front wheel drive system in such a manner that it can be shut off.
The clutch is
A first inner ring disposed on a radially outer side of the output shaft;
A first outer ring disposed radially outward of the first inner ring;
A first inner circumferential raceway surface formed on the inner circumferential surface of the first outer ring;
A first outer raceway surface facing the first inner raceway surface and formed on the outer circumference surface of the first inner ring;
The first outer raceway surface and the first inner raceway surface are interposed between the first inner raceway surface and the first outer race by relative rotation in a predetermined direction of the first inner ring and the first outer ring. A plurality of first rollers that engage with the raceway surface and transmit rotational power;
A first cage that holds the plurality of first rollers spaced apart from each other in the circumferential direction while being inclined at a predetermined angle from a surface including the axis of the output shaft;
One of the first inner ring or the first outer ring is configured to be rotatable integrally with the output shaft,
The other of the first inner ring or the first outer ring is configured to be relatively rotatable and axially movable with respect to one of the first inner ring or the first outer ring, and the first inner ring or the first outer ring. A sprocket or gear configured to be integrally rotatable with the other outer ring;
The sprocket engages with an endless chain that transmits power to the front wheel drive system,
The gear is formed with teeth having a predetermined torsion angle so that the tooth traces are not parallel to the shaft center, and is engaged with a driven gear that transmits power to the front wheel drive system,
The torsional direction of the gear includes a direction of a thrust force generated in the gear when engaging with the driven gear and transmitting power, and the first roller on the first inner raceway surface and the first outer raceway surface. Is set to coincide with the direction in which the other of the first inner ring or the first outer ring moves when engaging and transmitting power.
A power transmission device configured to transmit power of the output shaft to the front wheel drive system when a rotation speed of the rear wheel drive system is higher than a rotation speed of the front wheel drive system. The clutch is
A second inner ring disposed outside the output shaft in the radial direction and juxtaposed in the axial direction of the first inner ring;
A second outer ring disposed radially outside the second inner ring and arranged in parallel in the axial direction of the first outer ring;
A second inner circumferential raceway surface formed on the inner circumferential surface of the second outer ring;
A second outer peripheral raceway surface facing the second inner peripheral raceway surface and formed on the outer peripheral surface of the second inner ring;
The second outer ring is interposed between the second outer raceway surface and the second inner raceway surface, and the second inner ring and the second outer ring rotate relative to each other in a direction opposite to the direction in which the first roller is engaged. A plurality of second rollers that engage with the inner circumferential raceway surface and the second outer circumferential raceway surface to transmit rotational power;
A second cage that holds the plurality of second rollers spaced apart from each other in the circumferential direction while being inclined at a predetermined angle from a surface including the axis of the output shaft,
One of the second inner ring or the second outer ring is configured to rotate integrally with the output shaft,
The other of the second inner ring or the second outer ring is configured to be relatively rotatable and axially movable relative to one of the second inner ring or the second outer ring, and together with the sprocket or the gear, The first inner ring or the other of the first outer ring is configured to be rotatable integrally with the other,
The other inner side of the said 1st inner ring or the said 1st outer ring | wheel, and the moving means which moves the said 2nd inner ring | wheel or the said 2nd outer ring | wheel arranged in parallel to it in an axial direction are provided. The power transmission device according to 1.   The moving means is configured to pivot on the other of the first inner ring or the first outer ring and the second inner ring or the second outer ring arranged in parallel by the driving force of a solenoid that reciprocates or a motor that rotates. The power transmission device according to claim 2, wherein the power transmission device moves in a direction. When the first roller is engaged with the first inner raceway surface and the first outer raceway surface to transmit rotational power, the first inner ring or the first outer ring moves in the axial direction. A first elastic member for urging the inner ring or the first outer ring;
When the engagement between the first inner raceway surface and the first outer raceway surface and the first roller is released, the solenoid is used to bias the first inner ring or the first outer ring by the first elastic member. The power transmission device according to claim 3, further comprising a first bias release unit that operates and releases the motor. A second elastic member that urges the first inner ring or the first outer ring in an axial direction in a direction that prevents engagement between the first inner raceway surface and the first outer raceway surface and the first roller;
When the first roller is engaged with the first inner raceway surface and the first outer raceway surface, the solenoid or the motor biases the first inner ring or the first outer ring by the second elastic member. The power transmission device according to claim 3, further comprising: a second urging canceling unit that operates to cancel the operation.   A movement restricting means for restricting an axial movement amount of the first inner ring or the first outer ring when the first roller is engaged with the first outer raceway surface and the first inner circumference raceway surface; The power transmission device according to any one of claims 1 to 5.   The power transmission device according to any one of claims 1 to 6, further comprising an on / off means that is arranged on a power transmission path from the clutch to the front wheel drive system and interrupts power transmission.

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