VEHICLE POWER TRANSMISSION DEVICE

TECHNICAL FIELD

The present invention relates to a vehicle power transmission device equipped with a crank type continuously variable transmission mechanism.

BACKGROUND ART

A vehicle power transmission device that includes a plurality of crank type transmission units that convert rotation of an input shaft connected to an engine into back and forth movement of a connecting rod and convert back and forth movement of the connecting rod into rotation of an output shaft by means of a one-way clutch is known from Patent Document 1 below.

RELATED ART DOCUMENTS
Patent Documents

Patent Document 1: Japanese Patent Publication No. 2005-502543

SUMMARY OF THE INVENTION
Problems to be Solved by the Invention

In the vehicle power transmission device described in Patent Document 1 above, since the output shaft is supported on a transmission case via a bearing, and end parts of the connecting rods of the plurality of transmission units are each connected to the output shaft via a one-way clutch, if just one of these bearings and one-way clutches malfunctions, the output shaft becomes non-rotatable, and there is a possibility that the driven wheel connected to the output shaft will lock and the vehicle will be unable to travel.

The present invention has been accomplished in light of the above circumstances, and it is an object thereof to enable a vehicle to travel in the minimum necessary way even when an output shaft is seized in a vehicle power transmission device equipped with a crank type transmission unit.

Means for Solving the Problems

In order to attain the above object, according to a first aspect of the present invention, there is provided a vehicle power transmission device comprising a plurality of transmission units for transmitting rotation of an input shaft connected to a drive source to an output shaft, the transmission units being arranged side by side between the input shaft and the output shaft, the transmission units each comprising an input side fulcrum that has a variable amount of eccentricity from an axis of the input shaft and rotates together with the input shaft, a first one-way clutch that is connected to the output shaft, an output side fulcrum that is provided on an input member of the first one-way clutch, a connecting rod that has opposite ends thereof connected to the input side fulcrum and the output side fulcrum and moves back and forth, and a shift actuator that changes the amount of eccentricity of the input side fulcrum, wherein the output shaft comprises an output shaft main body portion connected to the transmission unit, and an output shaft downstream portion further on a downstream side in a power transmission direction than the output shaft main body portion, and a clutch is disposed between the output shaft main body portion and the output shaft downstream portion.

Further, according to a second aspect of the present invention, in addition to the first aspect, an input rotating member provided on the input shaft and an output rotating member provided on the output shaft downstream portion are connected by a power transmission member, and a second one-way clutch and selection switching means are disposed between the output rotating member and the output shaft downstream portion, the second one-way clutch being engaged when a rotational speed of the output shaft downstream portion exceeds a rotational speed of the output rotating member and being disengaged when the rotational speed of the output shaft downstream portion is less than the rotational speed of the output rotating member, and the selection switching means connecting the output rotating member to the output shaft downstream portion or disconnecting the output rotating member therefrom.

Furthermore, according to a third aspect of the present invention, in addition to the first or second aspect, the clutch is a one-way clutch that is engaged when the rotational speed of the output shaft main body portion exceeds the rotational speed of the output shaft downstream portion and is disengaged when the rotational speed of the output shaft main body portion is less than the rotational speed of the output shaft downstream portion.

Moreover, according to a fourth aspect of the present invention, in addition to the first aspect, the device comprises a rotating member disposed between the drive source and the input shaft, a first case covering the rotating member, a second case covering the clutch, a suction port formed in the first case so as to oppose an outer periphery of the rotating member, a communication opening providing communication between an interior of the first case and an interior of the second case, and a discharge port formed in the second case.

Further, according to a fifth aspect of the present invention, in addition to the fourth aspect, the suction port is disposed on the opposite side of the input shaft to the output shaft, and the discharge port is disposed on the opposite side of the output shaft to the input shaft.

Furthermore, according to a sixth aspect of the present invention, in addition to the fifth aspect, the suction port opens to a front of a vehicle body, and the discharge port opens to a rear of the vehicle body.

Moreover, according to a seventh aspect of the present invention, in addition to the sixth aspect, the second case covers an underneath and a front of the discharge port.

Further, according to an eighth aspect of the present invention, in addition to any one of the fourth to seventh aspects, the rotating member and the clutch overlap one another in an axial direction.

A first output shaft 12 of an embodiment corresponds to the output shaft of the present invention, an eccentric disk 18 of the embodiment corresponds to the input side fulcrum of the present invention, a pin 19c of the embodiment corresponds to the output side fulcrum of the present invention, an outer member 22 of the embodiment corresponds to the input member of the present invention, a first sprocket 26 of the embodiment corresponds to the input rotating member of the present invention, a second sprocket 27 of the embodiment corresponds to the output rotating member of the present invention, an endless chain 28 of the embodiment corresponds to the power transmission member of the present invention, a damper 51 of the embodiment corresponds to the rotating member of the present invention, an output side dog clutch 55 of the embodiment corresponds to the clutch of the present invention, a third one-way clutch 55′ of the embodiment corresponds to the clutch or the one-way clutch of the present invention, an output side dry multi-plate clutch 55″ of the embodiment corresponds to the clutch of the present invention, an engine E of the embodiment corresponds to the drive source of the present invention, and a second power transmission switching mechanism S2 of the embodiment corresponds to the selection switching mechanism of the present invention.

EFFECTS OF THE INVENTION

In accordance with the first aspect of the present invention, when the input shaft is rotated by means of the drive source, the input side fulcrum rotates eccentrically, when the connecting rod having one end connected to the input side fulcrum moves back and forth, the output side fulcrum connected to the other end of the connecting rod moves back and forth, and the output shaft thus rotates intermittently via the first one-way clutch; rotation of the input shaft is changed in speed at a gear ratio corresponding to the amount of eccentricity of the input side fulcrum and is transmitted to the output shaft.

Since the output shaft is formed from the output shaft main body portion connected to the transmission unit, and the output shaft downstream portion further on the downstream side in the power transmission direction than the output shaft main body portion, and the clutch is disposed between the output shaft main body portion and the output shaft downstream portion, when the output shaft main body portion is seized and cannot rotate, it is possible, by disengaging the clutch to thus detach the output shaft downstream portion from the output shaft main body portion, to prevent the driven wheel from being locked by the seized output shaft main body portion, thus enabling the vehicle to take refuge to a repair shop without any problem.

Furthermore, in accordance with the second aspect of the present invention, since the input rotating member provided on the input shaft and the output rotating member provided on the output shaft downstream portion are connected by means of the power transmission member, and the second one-way clutch and the selection switching means are disposed between the output rotating member and the output shaft downstream portion, the second one-way clutch being engaged when the rotational speed of the output shaft downstream portion exceeds the rotational speed of the output rotating member and being disengaged when the rotational speed of the output shaft downstream portion is less than the rotational speed of the output rotating member, and the selection switching means connecting the output rotating member to the output shaft downstream portion or disconnecting it therefrom, in a normal situation in which the selection switching means disconnects the output rotating member from the output shaft downstream portion, the driving force from the driven wheel due to deceleration of the vehicle can be transmitted back to the drive source via the output shaft downstream portion, the second one-way clutch, the output rotating member, the power transmission member, the input rotating member, and the input shaft, thereby generating a braking force due to engine braking, etc. without any problem.

Moreover, when the output shaft main body portion is seized, if the output rotating member is connected to the output shaft downstream portion by the selection switching means, by transmitting the driving force of the drive source to the output shaft downstream portion via the input shaft, the input rotating member, the power transmission member, and the output rotating member, the vehicle is able to take refuge to a repair shop by means of the driving force of the drive source, and when the vehicle stops, by disconnecting the output rotating member from the output shaft downstream portion by the selection switching means, the second one-way clutch slips, and running can be continued without stopping the drive source.

Furthermore, in accordance with the third aspect of the present invention, since the clutch is the one-way clutch that is engaged when the rotational speed of the output shaft main body portion exceeds the rotational speed of the output shaft downstream portion and is disengaged when the rotational speed of the output shaft main body portion is less than the rotational speed of the output shaft downstream portion, when the situation is normal, the one-way clutch is automatically engaged to thus enable transmission of the driving force from the transmission unit to the driven wheel, and when the output shaft is seized, the one-way clutch automatically disengages to thus block transmission of the driving force from the driven wheel back to the transmission unit.

Moreover, in accordance with the fourth aspect of the present invention, since the arrangement includes the rotating member disposed between the drive source and the input shaft, the first case covering the rotating member, the second case covering the clutch, the suction port formed in the first case so as to oppose the outer periphery of the rotating member, the communication opening providing communication between the interior of the first case and the interior of the second case, and the discharge port formed in the second case, it is possible to supply cooling air, which has been sucked into the first case through the suction port by means of rotation of the rotating member, to the interior of the second case via the communication opening to thus cool the clutch, and then discharge it from the discharge port. Furthermore, since cooling air is generated by utilizing the existing rotating member, it becomes unnecessary to employ a special cooling fan, etc., thus cutting the number of components and the cost.

Moreover, in accordance with the fifth aspect of the present invention, since the suction port is disposed on the opposite side of the input shaft to the output shaft, and the discharge port is disposed on the opposite side of the output shaft to the input shaft, it is possible to dispose the suction port, the rotating member, the clutch, and the discharge port in series, thus reducing the pressure loss of cooling air and thereby efficiently applying cooling air generated by the rotating member to the clutch.

Furthermore, in accordance with the sixth aspect of the present invention, since the suction port opens to the front of the vehicle body, and the discharge port opens to the rear of the vehicle body, it is possible to assist cooling air generated by the rotating member by means of air flow of the vehicle, thus further enhancing the cooling effect for the clutch.

Moreover, in accordance with the seventh aspect of the present invention, since the second case covers the underneath and the front of the discharge port, it is possible to prevent water or mud splashed up by a wheel from entering the interior of the second case via the discharge port.

Furthermore, in accordance with the eighth aspect of the present invention, since the rotating member and the clutch overlap one another in the axial direction, it is possible to efficiently supply cooling air generated by the rotating member to the clutch with a minimum pressure loss.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a skeleton diagram of a vehicle power transmission device. (first embodiment)

FIG. 2 is a detailed diagram of part 2 in FIG. 1. (first embodiment)

FIG. 3 is a sectional view (TOP state) along line 3-3 in FIG. 2. (first embodiment)

FIG. 4 is a sectional view (LOW state) along line 3-3 in FIG. 2. (first embodiment)

FIG. 5 is a diagram for explaining the operation in the TOP state. (first embodiment)

FIG. 6 is a diagram for explaining the operation in the LOW state. (first embodiment)

FIG. 7 is a detailed diagram of part 7 in FIG. 1. (first embodiment)

FIG. 8 is a table for engagement of first and second meshing switching mechanisms. (first embodiment)

FIG. 9 is a torque flow diagram in a parking range. (first embodiment)

FIG. 10 is a torque flow diagram in a reverse range. (first embodiment)

FIG. 11 is a torque flow diagram in a neutral range. (first embodiment)

FIG. 12 is a torque flow diagram in a drive range. (normal travel state) (first embodiment)

FIG. 13 is a torque flow diagram in a drive range. (engine braking state) (first embodiment)

FIG. 14 is a torque flow diagram in a drive range. (idling stop state) (first embodiment)

FIG. 15 is a torque flow diagram in a drive range. (fail state) (first embodiment)

FIG. 16 is a detailed view of part 16 in FIG. 1. (first embodiment)

FIG. 17 is a view corresponding to FIG. 7. (second embodiment)

FIG. 18 is a view corresponding to FIG. 7. (third embodiment)

FIG. 19 is an enlarged view of part 19 in FIG. 18. (third embodiment)

FIG. 20 is a sectional view along line 20-20 in FIG. 19. (third embodiment)

EXPLANATION OF REFERENCE NUMERALS AND SYMBOLS

11 Input shaft

12 First output shaft (output shaft)

12A Output shaft main body portion

12B Output shaft downstream portion

14 Shift actuator

18 Eccentric disk (input side fulcrum)

19 Connecting rod

19
c Pin (output side fulcrum)

21 First one-way clutch

22 Outer member (input member)

26 First sprocket (input rotating member)

27 Second sprocket (output rotating member)

28 Endless chain (power transmission member)

45 Second one-way clutch

51 Damper (rotating member)

55 Output side dog clutch (clutch)

55′ Third one-way clutch (clutch, one-way clutch)

55″ Output side dry multi-plate clutch (clutch)

65 First case

66 Second case

67 Suction port

68 Discharge port

69 Communication hole

E Engine (drive source)

S2 Second power transmission switching mechanism (selection switching means)

U Transmission unit

MODES FOR CARRYING OUT THE INVENTION

A first embodiment of the present invention is explained below by reference to FIG. 1 to FIG. 16.

First Embodiment

As shown in FIG. 1, a vehicle power transmission device for transmitting the driving force of an engine E to driven wheels W and W via left and right axles 10 and 10 includes a continuously variable transmission T, a first power transmission switching mechanism S1, a second power transmission switching mechanism S2, and a differential gear D. The first power transmission switching mechanism S1 can switch between a parking range, a reverse range, a neutral range, and a drive range. The second power transmission switching mechanism S2 can switch between a normal travel/engine braking state, an idling stop state, and a fail state.

The structure of the vehicle power transmission device is now explained by reference to FIGS. 1 to 7.

As shown in FIG. 1, an input shaft 11 is formed from an input shaft main body portion 11A and an input shaft upstream portion 11B further on the upstream side (engine E side) in the driving force transmission direction than the input shaft main body portion 11A, the input shaft main body portion 11A being connected to the continuously variable transmission T, and the input shaft upstream portion 11B being connected to the engine E. A damper 51 is provided between the input shaft upstream portion 11B and the engine E, and an input side dog clutch 52 is provided between the input shaft main body portion 11A and the input shaft upstream portion 11B. The input side dog clutch 52 is maintained in an engaged state when the situation is normal, but the engagement is released when the input shaft main body portion 11A is seized, which is described later, thus detaching the input shaft main body portion 11A from the input shaft upstream portion 11B.

Furthermore, an output shaft 12 is formed from an output shaft main body portion 12A and an output shaft downstream portion 12B further on the downstream side (driven wheels W and W side) in the driving force transmission direction than the output shaft main body portion 12A, the output shaft main body portion 12A being connected to the continuously variable transmission T, and the output shaft downstream portion 12B being connected to the second power transmission switching mechanism S2. An output side dog clutch 55 is provided between the output shaft main body portion 12A and the output shaft downstream portion 12B. The output side dog clutch 55 is maintained in an engaged state when the situation is normal, but the engagement is released when the input shaft main body portion 12A is seized, which is described later, thus detaching the output shaft main body portion 12A from the output shaft downstream portion 12B.

As shown in FIG. 16, the right end of the input shaft main body portion 11A is supported on a transmission case, which is not illustrated, via a ball bearing 53, and the outer periphery at the left end of the input shaft upstream portion 11B is relatively rotatably fitted into the inner periphery at the right end of the input shaft main body portion 11A. The inner periphery of the input side dog clutch 52 is spline fitted onto the outer periphery of the input shaft main body portion 11A and the outer periphery of the input shaft upstream portion 11B, and when the input side input side dog clutch 52 is moved leftward by means of a fork 54, the spline of the input side dog clutch 52 is disengaged from the spline of the input shaft upstream portion 11B, thus detaching the input shaft main body portion 11A from the input shaft upstream portion 11B.

The structure of the output side dog clutch 55 is substantially the same as the structure of the input side dog clutch 52, which is described above.

As shown in FIG. 2 and FIG. 3, the continuously variable transmission T of the present embodiment has a plurality (four in the embodiment) of transmission units U having the same structure superimposed on one another in the axial direction; these transmission units U include a common input shaft 11 and a common first output shaft 12 disposed in parallel to each other, and rotation of the input shaft 11 is reduced in speed or increased in speed and transmitted to the first output shaft 12.

The structure of one transmission unit U is explained below as being representative thereof The input shaft 11, which is connected to the engine E and rotates, extends relatively rotatably through the interior of a hollow rotating shaft 14a of a shift actuator 14 such as an electric motor. A rotor 14b of the shift actuator 14 is fixed to the rotating shaft 14a, and a stator 14c is fixed to a casing. The rotating shaft 14a of the shift actuator 14 can rotate at the same speed as that of the input shaft 11 and can rotate at a different speed relative to the input shaft 11.

A first pinion 15 is fixed to the input shaft 11, which extends through the rotating shaft 14a of the shift actuator 14, and a crank-shaped carrier 16 is connected to the rotating shaft 14a of the shift actuator 14 so as to straddle the first pinion 15. Two second pinions 17 and 17 having the same diameter as that of the first pinion 15 are each supported via pinion pins 16a and 16a at positions forming an equilateral triangle in cooperation with the first pinion 15, and a ring gear 18a eccentrically formed in the interior of a circular plate-shaped eccentric disk 18 meshes with the first pinion 15 and the second pinions 17 and 17. A ring portion 19b provided at one end of a rod portion 19a of a connecting rod 19 is relatively rotatably fitted onto an outer peripheral face of the eccentric disk 18 via a ball bearing 20.

A first one-way clutch 21 provided on the outer periphery of the first output shaft 12 includes a ring-shaped outer member 22 pivotably supported on the rod portion 19a of the connecting rod 19 via a pin 19c, an inner member 23 disposed in the interior of the outer member 22 and fixed to the first output shaft 12, and rollers 25 disposed in a wedge-shaped space formed between an arc face on the inner periphery of the outer member 22 and a flat plane on the outer periphery of the inner member 23 and urged by means of springs 24.

As is clear from FIG. 2, the four transmission units U share the crank-shaped carrier 16, but the phase of each eccentric disk 18 supported on the carrier 16 via the second pinions 17 and 17 is different by 90° for each transmission unit U. For example, in FIG. 2, the eccentric disk 18 of the transmission unit U at the left-hand end is displaced upward relative to the input shaft 11 in the drawing, the eccentric disk 18 of the transmission unit U third from the left is displaced downward relative to the input shaft 11 in the drawing, and the eccentric disks 18 and 18 of the transmission units U and U second and fourth from the left are positioned in the middle in the vertical direction.

As is clear from FIG. 1, the continuously variable transmission T includes an auxiliary power transmission path that can transmit a driving force via a separate path from that by the six transmission units U. That is, a first sprocket 26 provided on the input shaft upstream portion 11B on the upstream side (engine E side) of the input shaft 12 and a second sprocket 27 provided on transmission shaft 13 relatively rotatably fitted around the outer periphery of the output shaft downstream portion 12B on the downstream side (differential gear D side) of the first output shaft 13 are connected via an endless chain 28; the first sprocket 26, the second sprocket 27, and the endless chain 28 form auxiliary power transmission means 29.

As is clear from FIG. 7, the first power transmission switching mechanism S1 includes, in addition to the tubular first output shaft 12 relatively rotatably fitted onto the outer periphery of the axle 10, a tubular second output shaft 31 relatively rotatably fitted onto the outer periphery of the axle 10 and a tubular third output shaft 32 relatively rotatably fitted onto the outer periphery of the second output shaft 31. A fourth outer peripheral spline 12a is formed on the right end of the output shaft downstream portion 12B of the first output shaft 12, a fifth outer peripheral spline 31a is formed on the left end of the second output shaft 31, and a sixth outer peripheral spline 32a is formed on the left end of the third output shaft 32.

The fourth outer peripheral spline 12a, the fifth outer peripheral spline 31a, and the sixth outer peripheral spline 32a form a first meshing switching mechanism 33, which is a dog clutch, and are aligned in the axial direction, the external diameters of the fifth outer peripheral spline 31a and the sixth outer peripheral spline 32a being equal to each other but smaller than the external diameter of the fourth outer peripheral spline 12a. A sleeve 34 of the first meshing switching mechanism 33 includes a second inner peripheral spline 34a having a large external diameter and a third inner peripheral spline 34b having a small external diameter; the second inner peripheral spline 34a always meshes with the fourth outer peripheral spline 12a, the third inner peripheral spline 34b always meshes with the sixth outer peripheral spline 32a, and the third inner peripheral spline 34b meshes with the fifth outer peripheral spline 31a only when moved to the left as shown in FIG. 7. That is, when the sleeve 34 is moved by a fork 34c to the right from the leftward moved state shown in FIG. 7, meshing between the third inner peripheral spline 34b and the fifth outer peripheral spline 31a is released.

A planetary gear mechanism 35 includes a sun gear 36 as a first element, a carrier 37 as a third element, a ring gear 38 as a second element, and a plurality of pinions 39 relatively rotatably supported on the carrier 37, the pinions 39 meshing with the sun gear 36 and the ring gear 38. The sun gear 36 is joined to the right-hand end of the third output shaft 32, and the ring gear 38 is connected to the right-hand end of the second output shaft 31.

A first inner peripheral spline 41a formed on a sleeve 41 of a second meshing switching mechanism 40, which is a dog clutch, meshes with an outer peripheral spline 37a formed on an outer peripheral part of the carrier 37 and an outer peripheral spline 42a formed on a casing 42. Therefore, when the sleeve 41 is moved leftward by a fork 41b to the position shown in FIG. 7, the carrier 37 is detached from the casing 42, and when the sleeve 41 is moved rightward by the fork 41b from the position shown in FIG. 8, the carrier 37 is joined to the casing 42.

The second power transmission switching mechanism S2 is provided between the transmission shaft 13 and the output shaft downstream portion 12B and includes a first outer peripheral spline 13a provided on the transmission shaft 13, a second outer peripheral spline 12b and a third outer peripheral spline 12c provided on the output shaft downstream portion 12B, a sleeve 43 equipped with an inner peripheral spline 43a, a fork 43b for driving the sleeve 43, and a second one-way clutch 45 disposed between the output shaft downstream portion 12B and the second outer peripheral spline 12b.

The sleeve 43 can take a leftward position in which the first outer peripheral spline 13a and the second outer peripheral spline 12b are joined, a middle position in which the first outer peripheral spline 13a, the second outer peripheral spline 12b, and the third outer peripheral spline 12c are joined, and a rightward position in which the second outer peripheral spline 12b and the third outer peripheral spline 12c are joined. Furthermore, the second one-way clutch 45 disposed between the output shaft downstream portion 12B and the second outer peripheral spline 12b is engaged when the rotational speed of the output shaft downstream portion 12B exceeds the rotational speed of the transmission shaft 13.

A differential case 47 forming an outer shell of the differential gear D is joined to the right-hand end of the second output shaft 31. The differential gear D includes a pair of pinions 49 and 49 rotatably supported on a pinion shaft 48 fixed to the differential case 47, and side gears 50 and 50 fixedly provided on end parts of the axles 10 and 10 and meshing with the pinions 49 and 49.

The operation of the embodiment of the present invention having the above arrangement is now explained.

First, the operation of one transmission unit U of the continuously variable transmission T is explained. When the rotating shaft 14a of the shift actuator 14 is rotated relative to the input shaft 11, the carrier 16 rotates around an axis L1 of the input shaft 11. In this process, a center O of the carrier 16, that is, the center of the equilateral triangle formed by the first pinion 15 and the two second pinions 17 and 17, rotates around the axis L1 of the input shaft 11.

FIG. 3 and FIG. 5 show a state in which the center O of the carrier 16 is present on the side opposite to the first output shaft 12 with respect to the first pinion 15 (that is, the input shaft 11); here, the amount of eccentricity of the eccentric disk 18 relative to the input shaft 11 becomes a maximum, and the ratio of the continuously variable transmission T attains a TOP state. FIG. 4 and FIG. 6 show a state in which the center O of the carrier 16 is present on the same side as the first output shaft 12 with respect to the first pinion 15 (that is, the input shaft 11); here, the amount of eccentricity of the eccentric disk 18 relative to the input shaft 11 becomes a minimum, and the ratio of the continuously variable transmission T attains a LOW state.

When in the TOP state shown in FIG. 5 the input shaft 11 is rotated by the engine E and the rotating shaft 14a of the shift actuator 14 is rotated at the same speed as that of the input shaft 11; in a state in which the input shaft 11, the rotating shaft 14a, the carrier 16, the first pinion 15, the two second pinions 17 and 17, and the eccentric disk 18 are integrated, they rotate eccentrically in the counterclockwise direction (see arrow A) with the input shaft 11 as the center. While rotating from FIG. 5 (A) to FIG. 5 (B) and then to the state of FIG. 5 (C), the connecting rod 19, which has the ring portion 19b relatively rotatably supported on the outer periphery of the eccentric disk 18 via the ball bearing 20, rotates the outer member 22, which is pivotably supported at the extremity of the rod portion 19a by means of the pin 19c, in the counterclockwise direction (see arrow B). FIG. 5 (A) and FIG. 5 (C) denote opposite ends of rotation in the arrow B direction of the outer member 22.

When the outer member 22 rotates in the arrow B direction in this way, the rollers 25 bite into the wedge-shaped space between the outer member 22 and the inner member 23 of the first one-way clutch 21, rotation of the outer member 22 is transmitted to the first output shaft 12 via the inner member 23, and the first output shaft 12 therefore rotates in the counterclockwise direction (see arrow C).

When the input shaft 11 and the first pinion 15 rotate further, the eccentric disk 18 having the ring gear 18a meshing with the first pinion 15 and the second pinions 17 and 17 rotates eccentrically in the counterclockwise direction (see arrow A). While rotating from FIG. 5 (C) to FIG. 5 (D) and then to the state of FIG. 5 (A), the connecting rod 19 having the ring portion 19b relatively rotatably supported on the outer periphery of the eccentric disk 18 via the ball bearing 20 rotates the outer member 22, which is pivotably supported at the extremity of the rod portion 19a by means of the pin 19c, in the clockwise direction (see arrow B′). FIG. 5 (C) and FIG. 5 (A) denote opposite ends of rotation in the arrow B′ direction of the outer member 22.

When the outer member 22 rotates in the arrow B′ direction in this way, the rollers 25 are pushed out from the wedge-shaped space between the outer member 22 and the inner member 23 while compressing the springs 24, the outer member 22 slips against the inner member 23, and the first output shaft 12 does not rotate.

As hereinbefore described, when the outer member 22 rotates back and forth, since the first output shaft 12 rotates in the counterclockwise direction (see arrow C) only when the direction of rotation of the outer member 22 is counterclockwise (see arrow B), the first output shaft 12 rotates intermittently.

FIG. 6 shows the operation when the continuously variable transmission T is run in the LOW state. In this process, since the position of the input shaft 11 coincides with the center of the eccentric disk 18, the amount of eccentricity of the eccentric disk 18 relative to the input shaft 11 becomes zero. When in this state the input shaft 11 is rotated by the engine E and the rotating shaft 14a of the shift actuator 14 is rotated at the same speed as that of the input shaft 11; in a state in which the input shaft 11, the rotating shaft 14a, the carrier 16, the first pinion 15, the two second pinions 17 and 17, and the eccentric disk 18 are integrated, they rotate eccentrically in the counterclockwise direction (see arrow A) with the input shaft 11 as the center. However, since the amount of eccentricity of the eccentric disk 18 is zero, the stroke of back and forth movement of the connecting rod 19 also becomes zero, and the first output shaft 12 does not rotate.

Therefore, setting the position of the carrier 16 between the TOP state of FIG. 3 and the LOW state of FIG. 4 by driving the shift actuator 14 enables running to be carried out at any ratio between a ratio of zero and a predetermined ratio.

Since, with regard to the continuously variable transmission T, the phases of the eccentric disks 18 of the four transmission units U disposed side by side are displaced from each other by 90°, transmitting the driving force in turn from the four transmission units U, that is, putting at least one of the four first one-way clutches 21 in an engaged state at any one time, enables the first output shaft 12 to be rotated continuously.

The operation of the first power transmission switching mechanism S1, which switches between the parking range, the reverse range, the neutral range, and the drive range, is now explained.

As shown in FIG. 8 and FIG. 9, when the sleeve 34 of the first meshing switching mechanism 33 is moved to the left to thus join the output shaft downstream portion 12B of the first output shaft 12, the second output shaft 31, and the third output shaft 32 as a unit, and the sleeve 41 of the second meshing switching mechanism 40 is moved to the right to thus join the carrier 37 of the planetary gear mechanism 35 to the casing 42, the parking range is established.

In the parking range, the second output shaft 31, which is integral with the differential case 47, is joined to the ring gear 38 of the planetary gear mechanism 35, the second output shaft 31 is connected to the sun gear 36 of the planetary gear mechanism 35 via the first meshing switching mechanism 33 and the third output shaft 32 and, furthermore, the carrier 37 of the planetary gear mechanism 35 is joined to the casing 42 via the second meshing switching mechanism 40. As a result, the planetary gear mechanism 35 attains a locked state, and the driven wheels W and W connected thereto via the differential gear D are non-rotatably restrained.

As shown in FIG. 8 and FIG. 10, when the sleeve 34 of the first meshing switching mechanism 33 is moved to the right to thus join the output shaft downstream portion 12B and the third output shaft 32 and detach the second output shaft 31, and the sleeve 41 of the second meshing switching mechanism 40 is moved to the right to thus join the carrier 37 of the planetary gear mechanism 35 to the casing 42, the reverse range is established.

In the reverse range, the driving force outputted from the continuously variable transmission T to the output shaft downstream portion 12B of the first output shaft 12 is transmitted to the differential case 47 via the path: first meshing switching mechanism 33→third output shaft 32→sun gear 36→carrier 37→ring gear 38, and at the same time it is reduced in speed and reversed in rotation in the planetary gear mechanism 35, thus enabling the vehicle to be made to travel in reverse.

As shown in FIG. 8 and FIG. 11, when the sleeve 34 of the first meshing switching mechanism 33 is moved to the right to thus join the the output shaft downstream portion 12B and the third output shaft 32 and detach the second output shaft 31, and the sleeve 41 of the second meshing switching mechanism 40 is moved to the left to thus detach the carrier 37 of the planetary gear mechanism 35 from the casing 42, the neutral range is established.

In the neutral range, since the carrier 37 of the planetary gear mechanism 35 is detached from the casing 42, the ring gear 38 can rotate freely, and since the second output shaft 31 can rotate freely, the differential case 47 can rotate freely, the driven wheels W and W thereby attaining a non-restrained state. In this state, the driving force of the engine E is transmitted from the continuously variable transmission T to the sun gear 36 via the path: output shaft downstream portion 12B→first meshing switching mechanism 33→third output shaft 32, but since the carrier 37 is not restrained, the planetary gear mechanism 35 idles, and the driving force is not transmitted to the differential gear D.

As shown in FIG. 9 and FIG. 12, when the sleeve 34 of the first meshing switching mechanism 33 is moved to the left to thus integrally join the the output shaft downstream portion 12B, the second output shaft 31, and the third output shaft 32, and the sleeve 41 of the second meshing switching mechanism 40 is moved to the left to thus detach the carrier 37 of the planetary gear mechanism 35 from the casing 42, the drive range is established.

In the drive range, since the ring gear 38 and the sun gear 36 of the planetary gear mechanism 35 are joined to each other by means of the first meshing switching mechanism 33, the planetary gear mechanism 35 attains a state in which it can rotate as a unit. As a result, the driving force outputted from the continuously variable transmission T to the the output shaft downstream portion 12B is transmitted to the differential case 47 via the path: first meshing switching mechanism 33→second output shaft 31 or via the path: first meshing switching mechanism 33→third output shaft 32→sun gear 36→carrier 37→ring gear 38, thus enabling the vehicle to be made to travel forward.

As hereinbefore described, since the driving force is transmitted via the first one-way clutches 21, the first output shaft 12 of the continuously variable transmission T of the present embodiment can rotate only in the direction of forward travel, but disposing the first power transmission switching mechanism S1 having a forward-reverse switching function on the downstream side of the first output shaft 12 enables the vehicle to be made to travel in reverse without hybridization, in which an electric motor is provided for reverse travel.

Moreover, since the first power transmission switching mechanism S1 can establish the parking range and the neutral range in addition to the drive range and the reverse range, it is possible to further reduce the size and lighten the weight of the power transmission device itself.

The operation of the second power transmission switching mechanism S2 for switching between a normal travel/engine braking state, an idling stop state, and a fail state is now explained.

As shown in FIG. 10 and FIG. 12, in a normal state in which the first power transmission switching mechanism S1 is in any of the parking range, the reverse range, the neutral range, and the drive range, which are described above, the sleeve 41 of the second power transmission switching mechanism S2 moves leftward thus providing a connection between the first outer peripheral spline 13a of the transmission shaft 13 and the second outer peripheral spline 12b of the output shaft downstream portion 12B. Therefore, when the vehicle is traveling in the drive range or the reverse range, the driving force of the engine E is not only transmitted from the input shaft 11 to the output shaft downstream portion 12B via the transmission units U, but also transmitted from the input shaft 11 to the transmission shaft 13 via the auxiliary power transmission means 29 formed from the first sprocket 26, the endless chain 28, and the second sprocket 27, and transmitted from the first outer peripheral spline 13a of the transmission shaft 13 to the second outer peripheral spline 12b of the output shaft downstream portion 12B.

However, since the gear ratio of the transmission units U is set so as to be larger than the gear ratio of the auxiliary power transmission means 29, the rotational speed of the transmission shaft 13 (that is, the rotational speed of the second outer peripheral spline 12b) becomes larger than the rotational speed of the output shaft downstream portion 12B, the second one-way clutch 45 is disengaged, power transmission via the auxiliary power transmission means 29 is not carried out, and the vehicle is made to travel forward or in reverse by means of power transmission via the transmission units U.

When the vehicle is shifted to a deceleration state while it is traveling forward in the drive range, as shown in FIG. 13, the engine rotational speed decreases and the first one-way clutches 21 of the transmission units U are disengaged, and the driving force from the driven wheels W and W is transmitted to the output shaft downstream portion 12B via the differential gear D and the first power transmission switching mechanism S1. In this process, the rotational speed of the output shaft downstream portion 12B becomes larger than the rotational speed of the transmission shaft 13 connected to the input shaft 11 via the auxiliary power transmission mechanism 29 (that is, the rotational speed of second outer peripheral spline 12b), the second one-way clutch 45 is engaged, and the driving force of the output shaft downstream portion 12B is thereby transmitted back to the engine E via the auxiliary power transmission means 29 and the input shaft 11, thus effecting engine braking.

Even when the vehicle decelerates while it is traveling in reverse in the reverse range, since the output shaft downstream portion 12B rotates in the same direction as with forward travel in the drive range, engine braking can be effected in the same manner.

When the vehicle decelerates further while it is traveling in the drive range, as shown in FIG. 14, the second outer peripheral spline 12b and the third outer peripheral spline 12c of the output shaft downstream portion 12B are joined by moving the sleeve 41 of the second power transmission switching mechanism S2 rightward. As a result, the first output shaft 12, which is rotated by means of the driving force transmitted back from the driven wheels W and W, is detached from the transmission shaft 13 (that is, from the engine E), idling stop while decelerating is therefore enabled, and the fuel consumption can be reduced.

When there is a failure of the transmission units U and the vehicle is unable to travel, as shown in FIG. 15, the sleeve 41 of the second power transmission switching mechanism S2 is put into the middle position, and the first outer peripheral spline 13a of the transmission shaft 13 and the second outer peripheral spline 12b and the third outer peripheral spline 12c of the output shaft downstream portion 12B are joined. As a result, the transmission shaft 13 and the output shaft downstream portion 12B are directly joined without going through the second one-way clutch 45, the driving force of the engine E is therefore transmitted from the input shaft 11 to the driven wheels W and W via the auxiliary power transmission means 29, the transmission shaft 13, the output shaft downstream portion 12B, the first power transmission switching mechanism S1, and the differential gear D, and the vehicle can be made to travel forward or in reverse to a repair shop.

There is sometimes a malfunction in which the input shaft main body portion 11A is non-rotatably seized due to breakage of the ball bearing 53 (see FIG. 16) supporting the input shaft main body portion 11A or the ball bearing 20 (see FIG. 3) supporting the ring portion 19b of the connecting rod 19. When such a malfunction occurs, if the engine E and the input shaft main body portion 11A are inseparably connected to each other, the engine E will stall and be unable to run, and there is the problem that the vehicle is unable to travel.

However, in accordance with the present embodiment, since, when the input shaft main body portion 11A is seized, engagement of the input side dog clutch 52 is released to thus detach the input shaft main body portion 11A from the input shaft upstream portion 11B, due to switching to a fail state mode explained by reference to FIG. 15, the driving force of the engine E can be transmitted by means of the auxiliary power transmission means 29 from the input shaft upstream portion 11B to the output shaft downstream portion 12B without going through the continuously variable transmission T, thus enabling the vehicle to take refuge.

While taking refuge, the engine E and the driven wheels W and W are directly coupled, and it is therefore possible to actuate engine braking, but there is the problem that when the vehicle stops, the engine E, which is directly coupled to the driven wheels W and W, will stall. However, in accordance with the present embodiment, when the vehicle stops, if the sleeve 41 of the second power transmission switching mechanism S2 is moved leftward so as to connect the first outer peripheral spline 13a of the transmission shaft 13 and the second outer peripheral spline 12b of the output shaft downstream portion 12B, the driving force of the engine E inputted into the transmission shaft 13 is not transmitted to the output shaft downstream portion 12B due to the second one-way clutch 45 slipping, and even in a state in which the vehicle is stopped, idling is possible without the engine E stalling.

Moreover, if there is a breakage of the bearing supporting the output shaft main body portion 12A or the first one-way clutches 21 provided on the outer periphery of the output shaft main body portion 12A, a malfunction in which the output shaft main body portion 12A is non-rotatably seized might occur. In a case in which such a malfunction occurs, since rotation of the driven wheels W and W is transmitted back to the output shaft main body portion 12A, the vehicle becomes unable to travel, and when an attempt is made to take refuge by means of the auxiliary power transmission device 29, since the driving force is transmitted back to the output shaft main body portion 12A, which is seized, there is the problem that the vehicle is unable to travel.

However, in accordance with the present embodiment, when the output shaft main body portion 12A is seized, the input side dog clutch 52 is disengaged to thus detach the input shaft main body portion 11A from the input shaft upstream portion 11B, the output side dog clutch 55 is disengaged to thus detach the output shaft main body portion 12A from the output shaft downstream portion 12B, switching to the fail state mode explained by reference to FIG. 15 is thus carried out, the driving force of the engine E is transmitted by the auxiliary power transmission means 29 from the input shaft upstream portion 11B to the output shaft downstream portion 12B without going through the continuously variable transmission T, and the vehicle can take refuge without transmitting the driving force to the output shaft main body portion 12A, which has seized.

In this arrangement, if the input side dog clutch 52 were engaged, the driving force of the engine E would be transmitted to the seized output shaft main body portion 12A via the transmission units U and the first one-way clutches 21, but the above problem can be solved by disengaging the input side dog clutch 52 in advance.

In the same way as for a malfunction in which the input shaft upstream portion 11B is seized, while taking refuge the engine E and the driven wheels W and W are directly coupled, and engine braking can be actuated. Furthermore, when the vehicle stops while taking refuge, if the sleeve 41 of the second power transmission switching mechanism S2 is moved leftward, since the driving force of the engine E inputted into the transmission shaft 13 is not transmitted to the output shaft downstream portion 12B due to the second one-way clutch 45 slipping, even in a state in which the vehicle is stopped, idling is possible without stalling the engine E.

In a malfunction other than seizure of the input shaft main body portion 11A and seizure of the output shaft main body portion 12A, it is not always necessary to disengage the input side dog clutch 52, but if the input side dog clutch 52 is disengaged so as to detach the input shaft main body portion 11A from the input shaft upstream portion 11B, it becomes possible to prevent drag on the continuously variable transmission T, thus saving fuel consumption.

As hereinbefore described, in accordance with the present embodiment, engine braking is enabled both when traveling forward and when traveling in reverse while enabling the vehicle to travel forward and in reverse without using an electric motor, which would increase the axial dimension of the vehicle power transmission device and, moreover, idling stop while the vehicle is decelerating and traveling when there is a failure of the transmission units U are enabled. Furthermore, the vehicle power transmission device tends to increase the axial dimension on the input shaft 11 side, to which the engine E is connected, but providing the transmission shaft 13 on the first output shaft 12 side enables any increase in the axial dimension on the input shaft 11 side to be suppressed, thus minimizing the overall axial dimension of the vehicle power transmission device.

Furthermore, due to the input side dog clutch 52 being disposed between the input shaft main body portion 11A and the input shaft upstream portion 11B and the output side dog clutch 55 being disposed between the output shaft main body portion 12A and the output shaft downstream portion 12B, even if the input shaft main body portion 11A or the output shaft main body portion 12A is seized and malfunctions, the vehicle can take refuge. Moreover, since a dog clutch that is small in the axial direction is employed for the input side dog clutch 52 and the output side dog clutch 55, it is possible to avoid any increase in the dimension in the axial direction of the vehicle power transmission device. Furthermore, since the damper 51 is disposed between the engine E and the input shaft upstream portion 11B, the damping function of the damper 51 is exhibited even while taking refuge, thus ensuring good ride comfort.

A second embodiment of the present invention is now explained by reference to FIG. 17.

Second Embodiment

In the second embodiment, the output side dog clutch 55 disposed between the output shaft main body portion 12A and the output shaft downstream portion 12B in the first embodiment is replaced by a third one-way clutch 55′. The third one-way clutch 55′ is engaged when the rotational speed of an output shaft main body portion 12A exceeds the rotational speed of an output shaft downstream portion 12B, and is disengaged when the rotational speed of the output shaft main body portion 12A is less than the rotational speed of the output shaft downstream portion 12B.

When the output shaft main body portion 12A is seized and the vehicle is taking refuge, the rotational speed of the seized output shaft main body portion 12A is zero, whereas since the output shaft downstream portion 12B is rotated at a predetermined rotational speed by means of a driving force transmitted from auxiliary power transmission means 29 or a driving force transmitted back from driven wheels W and W, it is possible for the third one-way clutch 55′ to automatically disengage and prevent the driving force from being transmitted to the output shaft main body portion 12A. When the situation is normal, a driving force is transmitted from the output shaft main body portion 12A to the output shaft downstream portion 12B, and the third one-way clutch 55′ automatically engages, thus causing no problem in travel of the vehicle.

As described above, in accordance with the present embodiment, due to the output side dog clutch 55 being replaced by the third one-way clutch 55′, when the output shaft main body portion 12A is seized, the third one-way clutch 55′ is automatically disengaged without carrying out special control, thus enabling the vehicle to take refuge.

A third embodiment of the present invention is now explained by reference to FIG. FIG. 18 to FIG. 20.

Third Embodiment

The third embodiment includes an output side dry multi-plate clutch 55″ in place of the output side dog clutch 55 of the first embodiment. The output side dry multi-plate clutch 55″ includes a clutch outer 61 fixed to an output shaft main body portion 12A, a clutch inner 62 fixed to an output shaft downstream portion 12B, a plurality of frictional engagement elements 63 disposed between the clutch outer 61 and the clutch inner 62, and a solenoid 64 for putting the frictional engagement elements 63 in intimate contact with each other to thus engage the output side dry multi-plate clutch 55″.

A ring gear 51a is provided on the outer periphery of a damper 51 provided on an input shaft upstream portion 11B, a plunge type pinion of a starter motor, which is not illustrated, being capable of engaging with the ring gear 51a. The damper 51 and the output side dry multi-plate clutch 55″ overlap one another in the axial direction, the damper 51 being housed in a first case 65, and the output side dry multi-plate clutch 55″ being housed in a second case 66 continuous with the first case 65.

A suction port 67 facing the outer periphery of the ring gear 51a is formed in the first case 65, a discharge port 68 facing the outer periphery of the output side dry multi-plate clutch 55″ is formed in the second case 66, and a communication hole 69 is formed between the first case 65 and the second case 66. The suction port 67, the damper 51, the communication hole 69, the output side dry multi-plate clutch 55″, and the discharge port 68 are disposed in sequence from the front of the vehicle body to the rear of the vehicle body. The second case 66 includes a wall portion 66a covering the underneath and the front of the discharge port 68.

Therefore, when the output side dry multi-plate clutch 55″ generates heat while a continuously variable transmission T is running, due to the ring gear 51a on the outer periphery of the damper 51 rotating together with the input shaft 11, outside air is sucked into the interior of the first case 65 via the suction port 67, the outside air flows from the communication hole 69 to the interior of the second case 66, cools the output side dry multi-plate clutch 55″, and is then discharged from the discharge port 68 of the second case 66. In this way, cooling air is generated by utilizing the existing damper 51, and it is unnecessary to employ a special cooling fan, etc., thus cutting the number of components and the cost.

In particular, since the suction port 67 is disposed on the opposite side of the input shaft 11 (front side) to the output shaft 12, and the discharge port 68 is disposed on the opposite side of the output shaft 12 (rear side) to the input shaft 11, it is possible to dispose the suction port 67, the damper 51, the output side dry multi-plate clutch 55″, and the discharge port 68 in series, thereby utilizing the air flow of the vehicle and efficiently applying cooling air generated by the damper 51 to the output side dry multi-plate clutch 55″.

Furthermore, since the damper 51 and the output side dry multi-plate clutch 55″ overlap one another in the axial direction, it is possible to efficiently supply cooling air generated by the damper 51 to the output side dry multi-plate clutch 55″ with a minimum pressure loss. Moreover, since the second case 66 covers the underneath and the front of the discharge port 68 by means of the wall portion 66a, it is possible to prevent water or mud splashed up by a wheel from entering the interior of the second case 66 via the discharge port 68.

Embodiments of the present invention are explained above, but the present invention may be modified in a variety of ways as long as the modifications do not depart from the spirit and scope thereof.

For example, the number of transmission units U is not limited to four as in the embodiment.

Furthermore, the clutch of the present invention is not limited to the dog clutch 55, the one-way clutch 55′, or the output side dry multi-plate clutch 55″ of the embodiments, and any type of clutch may be employed.

Moreover, the rotating member of the present invention is not limited to the ring gear 51a of the damper 51 of the embodiment, and any rotating member such as a gear or a clutch may be used.

VEHICLE POWER TRANSMISSION DEVICE

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