JPH0727147A - Motive power transmitting device for four-wheel drive vehicle - Google Patents

Abstract

PURPOSE:To recover leaked oil through a microscopic passage, and transmit excellent torque by connecting a rotary shaft and a rotor to each other by spline coupling, and omitting a part of spline teeth of at least one of the rotary shaft and the rotor. CONSTITUTION:Oil leaked from the first side plate side passes through a microscopic clearance 40a, and reaches a clearance 45a between a rotary shaft SF and a hole 45 formed in the first side plate 40, and is returned again to an oil tank T by a return passage 43. Oil leaked from the second side plate 50 side passes through a microscopic clearance 50a, and reaches an oil chamber 58 partitioned by the inner periphery of the second side plate 50 and the outer periphery of the rotary shaft SF. The oil in this oil chamber 58 passes exclusively through a microscopic passage JS3, and is flowed to the clearance 45a between the rotary shaft SF and the hole 45 formed in the first side plate 40, and is returned again to the oil tank T by the return passage 43.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for a four-wheel drive vehicle, and more specifically to a power transmission for a four-wheel drive vehicle that transmits a rotational torque by a fluid pressure generated according to a difference in rotational speed between two rotary shafts. It relates to a transmission device.

[0002]

2. Description of the Related Art Generally, this type of power transmission device for a four-wheel drive vehicle is mainly used to improve the turning performance of the four-wheel drive vehicle and connects the front wheel side and the rear wheel side of the four-wheel drive vehicle. It is located between the propeller shafts. With this four-wheel drive vehicle power transmission device, the front wheel side propeller shaft and the rear wheel side propeller shaft can be connected while allowing a predetermined rotational speed difference therebetween.

A conventional power transmission device for a four-wheel drive vehicle H is shown in the following figures, and its structure and operation will be briefly described.
FIG. 3 is a schematic diagram showing the operating principle of the power transmission device H for a four-wheel drive vehicle. Referring to FIG. 3, 10 is a cam ring, 2
0 indicates a rotor. The rotor 20 is spline-coupled to a rotation shaft FP that is coupled to the front wheel side propeller shaft, and the cam ring 10 is coupled to a rear wheel side propeller shaft (not shown). The cam ring 10 has a concave portion 13 formed on the inner periphery thereof and contains the rotor 20 therein. The cam ring 10 and the rotor 20 can rotate relative to each other. The rotor 20 is provided with a plurality of vanes 21 that can advance and retreat in the radial direction of the rotor 20. The vane 21 is biased toward the cam ring 10 by a spring 22. Although not shown, the cam ring 10 and the rotor 20 are sandwiched by a pair of side plates from both sides, and the pump chamber 11 is defined by the recess of the cam ring 10, the rotor 20, and the side plate. The pump chambers 11 are formed at three locations on the inner peripheral side of the cam ring 10 at equal intervals in the circumferential direction.
The inside is filled with oil 30. Two inlets 12 for the oil 30 are provided in the pump chamber 11. Each inflow port 12 is connected to the oil tank T via the check valve CH1, and the oil 30 can flow from the oil tank T only to the low pressure portion 11b side of the pump chamber 11 described later.

If the cam ring 10 and the rotor 20 rotate relative to each other, for example, if the rotor 20 rotates clockwise relative to the cam ring 10 in FIG.
A high-pressure portion 11a is formed on the rotational direction side of the rotor 20, and a low-pressure portion 11b is formed on the opposite side of the high-pressure portion 11a with a vane 21 in between. Oil 3 on the high pressure part 11a side
0 flows through the orifice 23 provided in the vane 21 to the low pressure portion 11b side, thereby holding the hydraulic pressure generated in the high pressure portion 11a and holding the cam ring 10 and the rotor 20.
Allows relative rotation with. In this case, the high pressure section 11a
The hydraulic pressure generated on the side generates a rotation torque that rotates the cam ring 10 in the same direction as the rotation direction of the rotor 20. Although not shown, the high-pressure portions 11a and the low-pressure portions 11b of the pump chamber 11 formed at the above-mentioned three places are communicated with each other by a communication passage, and are arranged in the circumferential direction of the cam ring 10. The rotating torque is generated uniformly. The hydraulic pressure generated in the high pressure portion 11a is guided to the lower portion of the vane 21 so that the vane 21 can be surely biased toward the cam ring 10.

As a result, even if there is a rotational speed difference between the front wheel side and the rear wheel side of the propeller shaft, this rotational speed difference is tolerated and rotational torques are transmitted to each other, and the front wheel side and the rear wheel side are transmitted. The rotation speed can be automatically synchronized. FIG. 4 shows the power transmission device H for this four-wheel drive vehicle.
5 is a cross-sectional view of the oil 30 of FIG.
The leakage of the oil 30 in the power transmission device H for a four-wheel drive vehicle will be described.

As described above, the cam ring 10 and the rotor 20 are sandwiched by the side plates 40 and 50 from both sides as shown in FIG. Reference numeral 41 denotes a pressure guiding path for guiding the hydraulic pressure generated in the high pressure portion 11a described above to the lower portion of the vane 21 and pushing up the vane. Some of the oil 30 guided to the lower part of the vane 21 by the pressure guiding path 41 leaks from the minute gaps 40a, 50a between the side plates 40, 50 and the rotor 20.
The leaked oil 30 reaches the return passage 43 formed in the side plate 40, and is returned to the oil tank T by the return passage 43 to be circulated.

[0007]

Particularly, the side plate 5
The oil 30 leaking from the 0 side flows through the gap S between the spline-coupled rotating shaft FP and the rotor 20 and reaches the return path 43. However, since the gap S is very narrow, the flow resistance is large and the oil 30 does not easily flow. Therefore, there is a problem that a high hydraulic pressure is generated in the upstream side portion of the gap S, and this pressure damages the oil seal OS arranged on the upstream side. Further, as described above, if it becomes difficult for the oil 30 to flow between the gaps S,
The amount of oil returned to the oil tank T is insufficient, and the amount of oil in the oil tank T is insufficient. If the amount of oil in the oil tank T is insufficient, so-called cavitation may occur on the low pressure portion 11b side of the pump chamber 11. If this cavitation occurs, there is a problem that good torque cannot be transmitted.

In order to solve this problem, it is possible to form a return path similar to the return path 43 formed on the side plate 40 side also on the side plate 50 side.
By doing so, the oil 30 can be returned to the oil tank T through the return path having a small flow resistance, and the above problem can be solved. However, the side plate 50
Since the communication passages 51, 52, etc. for communicating the high pressure portions 11a and the low pressure portions 11b of the pump chambers 11 described above are formed on the side, the communication passages 51, 52, etc. are formed on the side plate 50 side. It is difficult to avoid the above and form a further return path, and it is difficult to realize because the cost increases significantly.

Therefore, an object of the present invention is to provide a structure in which leaked oil can be quickly circulated and returned to the oil tank without a significant increase in cost, so that good torque transmission can be achieved. A power transmission device for a driving vehicle is provided.

[0010]

A power transmission device for a four-wheel drive vehicle according to the present invention includes an annular cam ring to which a first drive shaft is connected and which has a plurality of recesses radially outwardly recessed in an inner circumference. ,
A rotating shaft connected to the second drive shaft is connected to the inner peripheral portion by spline connection, and the rotor housed inside the cam ring in a state of being rotatable relative to the cam ring, and the cam ring and the rotor are sandwiched from both sides. In the state
A pair of side plates integrally fastened to the cam ring, a plurality of pump chambers defined by the both side plates, the recess of the cam ring and the outer peripheral surface of the rotor, and in which oil is circulated between the pump chamber and the oil tank, Drive for a four-wheel drive vehicle provided with a return path which is formed on one of the side plates and collects oil leaking from between the other side plate and the rotor through gaps between teeth of the spline and returns the oil to the oil tank The force transmission device is characterized in that the gap includes a minute flow path formed by removing at least one spline tooth of the rotary shaft and the rotor.

[0011]

According to the power transmission device for a four-wheel drive vehicle of the present invention, the rotary shaft and the rotor are connected by spline coupling, and at least a part of the spline teeth of at least one of the rotary shaft and the rotor is connected. Due to the lack, a minute flow path is formed in the gap between the rotating shaft and the rotor. Therefore, when the power transmission device is operating, the oil leaked from between the rotor or the cam ring and the side plate is recovered through the minute flow path and promptly returns to the oil tank.

[0012]

Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments. FIG. 1 is a sectional view of a power transmission device H for a four-wheel drive vehicle according to an embodiment of the present invention. The power transmission device H for four-wheel drive vehicle of FIG. 1 has the same configuration as the conventional device shown in FIG. 4, and the same components are designated by the same reference numerals.

Referring to FIG. 1, a power transmission device H for a four-wheel drive vehicle transmits torque between a first drive shaft and a second drive shaft (not shown), and a cam ring. 10, the rotor 20, the rotation shaft SF, the first side plate 40 and the second side plate 50, and the casing 60 that accommodates them. The rotor 20 is housed inside the cam ring 10, and the cam ring 10 and the rotor 20 can rotate relative to each other. The first drive shaft is connected to the cam ring 10, and the rotary shaft SF connected to the second drive shaft is connected to the inner peripheral portion of the rotor 20 by spline connection. On the first drive shaft side and the second drive shaft side of the cam ring 10 and the rotor 20,
A first side plate 40 and a second side plate 50 are arranged respectively, and both plates 40, 50 are
The cam ring 10 is integrally fastened with a bolt B. Further, the casing 60 is provided on both side plates 4
0 and 50 are liquid-tightly covered, and an oil tank T is formed between the outer peripheral surfaces of the side plates 40 and 50 and the outer peripheral surface of the cam ring 10.

Referring to FIG. 3, the cam ring 10 has a plurality of recesses 13 formed radially outward in the inner circumference thereof. The recesses 13 of the cam ring 10, the rotor 20, and
The pump chamber 11 is defined by the side plates 40 and 50. The pump chamber 11 and the oil tank T
Is filled with oil 30. A pair of oil inlets 12 through which the oil 30 flows from the oil tank T into the pump chamber 11 are provided at both ends of the pump chamber 11 in the circumferential direction of the cam ring 10. In addition, pump room 1
1 is formed at three locations at equal intervals in the circumferential direction of the cam ring 10, and the oil inlet 1 is provided in each pump chamber 11.
2 are provided in pairs.

Referring to FIG. 2, the rotor 20 has a thick-walled cylindrical shape and has female spline teeth JS1 formed on the inner peripheral side thereof, and is spline-coupled with the rotary shaft SF as described above. The spline joint portion JS will be described in detail. On the rotation axis SF, male side spline teeth JS2 are formed. Then, as in the conventional case, a gap S is provided between the spline teeth JS1 and JS2.
Further, in the present embodiment, the spline teeth JS1 are missing teeth at substantially symmetrical positions in four directions on the cross section of the rotor 20, and the minute flow path JS3 is formed between the rotation shaft SF and the rotor 20. ing. With reference to FIG. 1, the minute flow path JS3 includes an oil chamber 58 defined by an inner circumference of a hole provided in the second side plate 50 and an outer circumference of the rotation shaft SF.
It serves as a passage that communicates the gap 45a between the first side plate 40 and the rotation shaft SF. In addition to the fact that only a part of the spline tooth JS1 is a missing tooth, the spline tooth JS1 is absent at a position symmetrical in the cross section of the rotor 20, so that a large stress concentration on the rotor 20 is suppressed, The strength of the rotor 20 is not significantly affected.

Further, referring to FIGS. 1 and 3, the rotor 20 is provided with a large number of vanes 21 which can advance and retreat in the radial direction of the rotor 20. As shown in FIG. 3, the vane 21 divides the pump chamber 11 into one end portion and the other end portion in the rotational direction of the rotor 20 with respect to the cam ring 10. The one end side portion in the rotation direction forms the high pressure portion 11a of the pump chamber 11, and the other end side portion in the rotation direction forms the low pressure portion 11b of the pump chamber 11. Further, the vane 21 is provided with an orifice 23, through which the oil 30 can move from the high pressure portion 11a to the low pressure portion 11b. A spring 22 is inserted at the bottom of the vane 21, and the vane 21 is urged toward the cam ring 10.

Referring to FIG. 1, the second side plate 50.
The oil tank T is provided with a pair of oil inflow passages 54 that connect the oil tank T with a pair of oil inlets 12 provided in any one of the three pump chambers 11. A check valve CH1 is disposed in each of the pair of oil inflow passages 54, and as shown in FIG. 3, allows the flow of the oil 30 only from the oil tank T to the low pressure portion 11b side of the pump chamber 11. ing. Further, as shown in FIG. 1, the second side plate 50 includes
A first annular groove 55 and a second annular groove 56 are formed respectively. Further, in the second side plate 50, a communication passage 57a for communicating the high pressure portions 11a with the first annular groove 55,
Further, a communication passage 57b is formed which communicates each low pressure portion 11b with the second annular groove 56. As a result, the high pressure portions 11a of the pump chambers 11 are connected to each other through the communication passage 57a and the first
Since they are communicated with each other through the annular groove 55, the pressure between the high pressure portions 11a can be made constant. Also, each pump room 1
The first low-pressure portions 11b are communicated with each other via the communication passage 57b and the second annular groove 56, so that the oil 30 can evenly flow into each low-pressure portion 11b. A hole into which the rotation shaft SF is inserted is provided in the center of the second side plate 50, and the rotation shaft SF is the bearing BR1.
It is rotatably supported by. The oil chamber 58 is defined by the inner circumference of the hole of the second side plate 50 and the outer circumference of the rotary shaft SF. In addition, the oil seal OS
The bearing BR1 is mounted on the rotor 20 side, and prevents the oil 30 from leaking from the oil chamber 58 to the outside.

Referring to FIG. 1, the first side plate 40
A pressure guiding path 41 for guiding the hydraulic pressure of the high pressure portion 11 a of the pump chamber 11 to the lower portion of the vane 21 is formed in the. This pressure guiding path 41 guides the hydraulic pressure of the high pressure portion 11 a of each pump chamber 11 to the lower portion of each vane 21, and a total of three pressure guiding paths 41.
Are formed. A check valve CH2 is disposed in each of the pressure guiding paths 41 so that the hydraulic pressure can be guided only from the pump chamber 11 side to the lower side of the vane 21. Therefore, each vane 21 has a spring 22
And is urged toward the cam ring 10 by the force of the above hydraulic pressure, and can surely slide on the cam ring 10 without creating a gap with the cam ring 10. In addition, a hole 45 into which the rotation shaft SF is inserted is provided in the central portion of the first side plate 40. The tip of the rotary shaft SF that penetrates the second side plate 50 and the rotor 20 is rotatably supported by the bearing BR2. Further, in the first side plate 40, the holes 4 are formed in a direction perpendicular to the axial direction of the holes 45.
A return path 43 that connects the oil tank 5 and the oil tank T is formed. The return path 43 is for returning leaked oil, which will be described later, collected in the gap 45a between the hole 45 and the rotary shaft SF to the oil tank T (see FIG. 3).

Next, the operation of the power transmission device H for a four-wheel drive vehicle will be described. Referring to FIG. 3, when rotor 20 rotates clockwise at a faster speed than cam ring 10, high-pressure portion 11 a is formed in pump chamber 11 on the rotation direction side of rotor 20, and vane 21 is separated. High voltage part 1
A low voltage portion 11b is formed on the opposite side of 1a. Low voltage section 11
On the side b, the oil 30 is sucked from the oil tank T,
The oil 30 on the high pressure portion 11a side flows through the orifice 23 provided in the vane 21 to the low pressure portion 11b side. As a result, the relative rotation between the cam ring 10 and the rotor 20 can be allowed while maintaining the hydraulic pressure generated in the high pressure portion 11a, and the hydraulic pressure generated in the high pressure portion 11a side causes the cam ring 10 to rotate in the rotational direction of the rotor 20. Produces a rotating torque that rotates in the same direction as. Therefore, even if a rotational speed difference occurs between the first drive shaft side and the second drive shaft side, the rotational speed difference between the two drive shafts is automatically recognized by allowing this rotational speed difference and transmitting rotational torque to each other. Tune in to.

While the power transmission device H for four-wheel drive vehicle is in operation, as shown in FIG. 1, the oil 30 on the high pressure portion 11a side is sent to the lower part of the vane 21 by the pressure guiding passage 41, but a very small amount. The oil 30 of each side plate 40,
Leakage occurs from the extremely small gaps 40a and 50a between the rotor 50 and the rotor 50 (which are gaps generated only when high pressure is generated). And
The oil 30 leaked from the first side plate 40 side passes through the minute gap 40a and then the first side plate 40.
It reaches the gap 45a between the hole 45 formed in the shaft and the rotary shaft SF, and is returned to the oil tank T again by the return passage 43. Further, the oil 30 leaking from the second side plate 50 side passes through the minute gap 50a and enters the oil chamber 58 defined by the inner circumference of the hole of the second side plate 50 and the outer circumference of the rotation shaft SF. Reach Then, the oil 30 in the oil chamber 58 flows exclusively through the minute flow path JS3 into the gap 45a between the hole 45 formed in the first side plate 40 and the rotation shaft SF, and again through the return path 43 the oil tank. Returned to T.

According to this embodiment, the oil 30 leaked from the side of the second side plate 50 is generated by the rotation shaft SF and the rotor 2.
Micro flow path JS formed in spline joint JS with 0
3 and the conventional gap S, and smoothly flow to the return path 43. Therefore, it is possible to prevent high pressure from being generated on the upstream side of the gap between the rotary shaft SF and the rotor 20, and thus to prevent the oil seal OS mounted on the rotary shaft SF from being damaged. Further, since the leaked oil 30 can be quickly circulated and returned to the oil tank T, the amount of oil in the oil tank T does not become insufficient. As a result, the low pressure side 11 of the pump chamber 11
It is possible to prevent cavitation from occurring in b. Moreover, it is very preferable that the spline tooth JS1 is a chipped tooth without causing a significant increase in cost. In particular, since the side of the rotor 20 formed by sintering is usually made to have a missing tooth, only a simple mold modification is required and the manufacturing cost hardly increases.

The present invention is not limited to the above embodiment, but the spline teeth JS2 on the side of the rotary shaft SF may be a missing tooth, or the spline teeth JS2, JS1 of both the rotary shaft SF and the rotor 20 may be used. Both may be missing teeth. Also, when the spline teeth JS2, JS1 are missing,
In addition to the missing teeth at the four-direction substantially symmetrical positions, the missing teeth may be provided at the three-direction substantially symmetrical positions or the two-direction symmetrical positions.

In addition, various design changes can be made within the scope of the present invention.

[0024]

According to the present invention, the oil leaked from the pump chamber can be quickly circulated through the minute flow path between the rotary shaft and the rotor and returned to the oil tank. Therefore, high pressure is prevented from being generated in the portion upstream of the minute flow path, and other mechanical elements and the like in the power transmission device for a four-wheel drive vehicle are not damaged. Further, since the leaked oil can be quickly returned to the oil tank, the amount of oil in the oil tank does not become insufficient, and cavitation does not occur in the pump chamber. In addition, the cost for cutting the spline teeth into a chipped tooth does not increase significantly.

As a result, without significantly increasing the cost,
It is possible to provide a power transmission device for a four-wheel drive vehicle that can always perform good torque transmission.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a power transmission device for a four-wheel drive vehicle according to an embodiment of the present invention.

FIG. 2 is a front view showing a spline coupling portion.

FIG. 3 is a schematic diagram showing an operation principle of a power transmission device for a four-wheel drive vehicle.

FIG. 4 is a sectional view of a conventional power transmission device for a four-wheel drive vehicle.

[Explanation of symbols]

 H Power transmission device for four-wheel drive vehicle 10 Cam ring 11 Pump chamber 13 Recess 20 Rotor 30 Oil 40 First side plate 43 Return path 50 Second side plate T Oil tank SF Rotation shaft JS Spline portion JS1 Rotor side spline tooth JS2 Rotation shaft Side spline tooth JS3 Micro flow path S Gap

Claims (1)

[Claims] 1. A ring-shaped cam ring, to which a first drive shaft is connected, having a plurality of recesses radially outwardly recessed, and a rotary shaft, which is connected to a second drive shaft, are spline-coupled to the inner peripheral part. A rotor housed in the cam ring in a state of being relatively rotatable with respect to the cam ring, and a pair of side plates integrally fastened to the cam ring with the cam ring and the rotor sandwiched from both sides, A plurality of pump chambers defined by the both side plates, the concave portion of the cam ring and the outer peripheral surface of the rotor, and in which oil is circulated between the oil tank, and one side plate, and the other side plate. For a four-wheel drive vehicle provided with a return path for collecting the oil leaking between the rotor and the rotor through the gap between the teeth of the spline and returning the oil to the oil tank. In the driving force transmission device, the gap includes a minute flow path formed by cutting out a part of at least one spline tooth of the rotary shaft and the rotor, for a four-wheel drive vehicle. Driving force transmission device.