JP2002301943A - Power transmission system for four-wheel drive vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize cost reduction by facilitating the working of side plates of a vane pump and to suppress a leakage of a working fluid from sliding surfaces of a rotor on the side plates in the case of a hydraulic coupling device of a power transmission system for a four-wheel drive vehicle. SOLUTION: Hydraulic components, such as oil passages, a check valve, and an orifice, are all disposed in a concentrated manner in the second side plate 32, one of the first and second side plates 30 and 32 with the rotor 35 of the vane pump P interposed between them. Communicating holes and communicating grooves in the side plate 32 formed in its thickness direction allow the side plate 32 to be manufactured by sintering molding, and its cost is thereby reduced. Further, the hydraulic components are prevented to the utmost from facing on the inner surface of the side plate 32 contacting with the rotor 35, thereby reducing the leakage of the working fluid.

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 having a hydraulic coupling device comprising a single vane pump between a main drive wheel and an auxiliary drive wheel.

[0002]

2. Description of the Related Art A power transmission device for a four-wheel drive vehicle has already been proposed by the present applicant in Japanese Patent Application No. Hei 10-238517. In the hydraulic coupling device used in this power transmission device, left and right first side plates and a central second side plate sandwich left and right cam rings to form outer shells of left and right vane pumps. Hydraulic elements such as an oil passage, a check valve, a switching valve, an orifice, and a reservoir are dispersedly arranged on the plate.

[0003]

However, in the above-mentioned conventional apparatus, since the respective hydraulic elements are dispersedly arranged on the three side plates, the processing of the side plates is troublesome and only increases the cost. However, there is a problem that the entire vane pump becomes large. Further, since many hydraulic elements are exposed on the side surface of the side plate that slides on the side surface of the rotor, there is a possibility that hydraulic oil leaks from the sliding surface. In particular, the switching valve that selectively communicates one of the suction port and the discharge port with the vane push-up port has a structure in which the valve body is swingably supported in a support groove recessed in a side surface of the second side plate. If the depth and shape of the support groove are not strictly managed, there is a possibility that the amount of hydraulic oil leak increases. Such a problem similarly occurs in a power transmission device in which a hydraulic coupling device having a single vane pump is disposed at an intermediate portion of a propeller shaft.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in a hydraulic coupling device for a power transmission device of a four-wheel drive vehicle, a side plate of a vane pump is easily processed to reduce costs and to reduce a cost. Further, it is an object to suppress leakage of hydraulic oil from a sliding surface of a side plate.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, an input shaft driven by an engine together with left and right main drive wheels and a left and right auxiliary drive wheel are provided. The vane pump includes a rotating output shaft, a vane pump that operates according to a relative rotational speed difference between the input shaft and the output shaft, and an orifice provided between a suction port and a discharge port of the vane pump. The rotor is housed in a space surrounded by the side plate, and a plurality of vanes radially slidably supported by the rotor are brought into sliding contact with a cam ring at a radially outer end. The port communicates with the annular vane push-up port facing the radially inner end of the vane through a communication passage. In a power transmission device of a four-wheel drive vehicle provided with a check valve that allows only the flow of hydraulic oil to the push-up port, an intake port, a discharge port, and a vane are formed on the inner surface of one side plate having an outer surface in contact with a casing. A communication groove formed with a push-up port, the communication path formed on the outer surface of the side plate, a first communication hole penetrating the side plate and communicating the communication groove with the suction port and the discharge port, and the side plate; A second communication hole that penetrates the communication groove to communicate with the vane push-up port, and a check ball is mounted on a valve seat formed in the first communication hole from the outer surface side of the side plate. A power transmission device for a four-wheel drive vehicle is proposed.

According to the above configuration, even if the relationship between the high pressure side and the low pressure side of the suction port and the discharge port is reversed according to the rotation direction of the vane pump, the high pressure side port and the vane are connected via the check valve provided in the communication passage. By communicating with the push-up groove, a high pressure is always introduced into the vane push-up groove to ensure the sealing property between the vane and the cam ring. Also, the first and second communication holes penetrating one of the side plates, the outer surfaces of which contact the casing, and the communication groove formed in the outer surface of the side plate, the communication port connecting the suction port and the discharge port to the vane push-up port. Since the passage is formed, not only the structure of the communication passage is simplified, but also the side plate can be manufactured by sintering, thereby contributing to cost reduction. Since it is formed on the outer surface of the side plate, which is the surface in the opposite direction, the sealing performance and the pump efficiency are also improved. Further, since a check ball is mounted on the valve seat formed in the first communication hole from the outer surface side of the side plate, the check valve can be extremely compactly stored inside the side plate, and The drop of the check ball can be prevented by the casing.

Incidentally, the front propeller shaft 1 of the embodiment
0f and the rear propeller shaft 10r respectively correspond to the input shaft and the output shaft of the present invention, and the first casing 21 of the embodiment corresponds to the casing of the present invention, and the first casing 21 of the embodiment.
The side plate 30 and the second side plate 32 correspond to the side plate of the present invention, and the left front wheel WFL of the embodiment is used.
The right front wheel WFR corresponds to the main drive wheel of the present invention, and the left rear wheel WRL and the right rear wheel WRL of the embodiment correspond to the auxiliary drive wheel of the present invention. The first communication hole and the second communication hole of the first embodiment are respectively the communication hole h1 and the communication hole h2 of the embodiment.
Corresponding to

According to the invention described in claim 2,
An input shaft driven by the engine together with the left and right main drive wheels, an output shaft rotating with the left and right auxiliary drive wheels, a vane pump that operates according to a relative rotational speed difference between the input shaft and the output shaft, a suction port of the vane pump, An orifice provided between the discharge ports, wherein the vane pump accommodates a rotor in a space surrounded by a cam ring and a pair of side plates, and includes a plurality of vanes slidably supported in the rotor in the radial direction. The outer end in the radial direction is brought into sliding contact with the cam ring, and one of the low-pressure side port of the suction port and the discharge port is communicated with the reservoir via a communication path, and the hydraulic oil flows from the reservoir to the low-pressure side port in this communication path. In a power transmission device of a four-wheel drive vehicle provided with a check valve that allows only A first communication port formed on the inner surface of the id plate with a suction port and a discharge port, the communication passage formed on the outer surface of the side plate, and a communication groove penetrating the side plate and communicating with the suction port and the discharge port; A check hole formed in the valve seat formed in the second communication hole from the outer surface side of the side plate, the communication hole including a communication hole and a second communication hole penetrating the side plate to communicate the communication groove with the reservoir; A power transmission device for a four-wheel drive vehicle, characterized in that the power transmission device is configured by mounting the power transmission device.

According to the above configuration, even if the relationship between the high pressure side and the low pressure side of the suction port and the discharge port is reversed according to the rotation direction of the vane pump, the low pressure side port and the reservoir are connected via the check valve provided in the communication passage. Can be communicated to prevent cavitation from occurring in the low pressure side port. In addition, the first and second communication holes penetrating one of the side plates having the outer surface in contact with the casing, and the communication groove formed in the outer surface of the side plate allow one of the low-pressure side port of the suction port and the discharge port to be connected to the reservoir. The structure of the communication passage is simplified, and the side plate can be manufactured by sintering, which contributes to cost reduction. Since the groove is formed on the outer surface of the side plate which is the surface in the opposite direction to the rotor, the sealing performance and the pump efficiency are also improved. Also, since a check ball is attached to the valve seat formed in the second communication hole from the outer surface side of the side plate, the check valve can be extremely compactly stored inside the side plate, and The drop of the check ball can be prevented by the casing.

The front propeller shaft 1 of the embodiment
0f and the rear propeller shaft 10r respectively correspond to the input shaft and the output shaft of the present invention, and the first casing 21 of the embodiment corresponds to the casing of the present invention, and the first casing 21 of the embodiment.
The side plate 30 and the second side plate 32 correspond to the side plate of the present invention, and the left front wheel WFL of the embodiment is used.
The right front wheel WFR corresponds to the main drive wheel of the present invention, and the left rear wheel WRL and the right rear wheel WRL of the embodiment correspond to the auxiliary drive wheel of the present invention. Further, the first communication hole and the second communication hole of claim 2 are respectively the communication hole h3 and the communication hole h4 of the embodiment.
Corresponding to

According to the third aspect of the present invention,
An input shaft driven by the engine together with the left and right main drive wheels, an output shaft rotating with the left and right auxiliary drive wheels, a vane pump that operates according to a relative rotational speed difference between the input shaft and the output shaft, a suction port of the vane pump, An orifice provided between the discharge ports, wherein the vane pump accommodates a rotor in a space surrounded by a cam ring and a pair of side plates, and includes a plurality of vanes slidably supported in the rotor in the radial direction. In a power transmission device for a four-wheel drive vehicle in which an outer end in a radial direction slides on a cam ring, a suction port, a discharge port, and a first communication groove are formed on an inner surface of one side plate having an outer surface in contact with a casing. A second communication groove is formed on an outer surface of the side plate, and a suction port and a discharge port are formed by a first communication hole penetrating the side plate. The port is connected to the second communication groove, the second communication groove is connected to the first communication groove by a pair of second communication holes penetrating the side plate, and the orifices are formed in the pair of second communication holes, respectively. A power transmission device for a four-wheel drive vehicle characterized by the following is proposed.

According to the above configuration, since a pair of orifices are provided in series in the first communication groove for communicating between the adjacent suction port and discharge port, the diameter of each orifice is increased to obtain the same throttle effect. This makes it possible not only to improve the durability against clogging of the orifice, but also to facilitate the drilling and improve the productivity. A first and a second communication hole penetrating one of the side plates having an outer surface in contact with the casing; a first communication groove formed on the inner surface of the side plate; and a second communication groove formed on the outer surface of the side plate. As a result, a communication path that allows the suction port and the discharge port to communicate with each other is formed, so that not only the structure of the communication path is simplified, but also the side plate can be manufactured by sintering and cost reduction. Since the second communication groove is formed on the outer surface of the side plate which is the surface in the opposite direction to the rotor, the sealing property is also improved. Further, since the orifice is formed in the second communication hole penetrating the side plate, the orifice can be extremely compactly arranged inside the side plate.

Incidentally, the front propeller shaft 1 of the embodiment
0f and the rear propeller shaft 10r respectively correspond to the input shaft and the output shaft of the present invention, and the first casing 21 of the embodiment corresponds to the casing of the present invention, and the first casing 21 of the embodiment.
The side plate 30 and the second side plate 32 correspond to the side plate of the present invention, and the left front wheel WFL of the embodiment is used.
The right front wheel WFR corresponds to the main drive wheel of the present invention, and the left rear wheel WRL and the right rear wheel WRL of the embodiment correspond to the auxiliary drive wheel of the present invention. Further, the first communication groove and the second communication groove of the third embodiment are respectively the communication groove g4 and the communication groove g3 of the embodiment.
And the first communication hole and the second communication hole of claim 3 are:
Each corresponds to the communication hole h3 and the communication hole h5 of the embodiment.

According to the fourth aspect of the present invention,
In addition to the configuration of claim 3, the orifice has a shape in which a pressure loss in a direction in which hydraulic oil flows when the vehicle travels forward is large, and a pressure loss in a direction in which hydraulic oil flows when the vehicle travels backward is small. A power transmission device for a four-wheel drive vehicle, characterized in that:

According to the above configuration, the front wheels are locked during sudden braking, the rotation speed of the rear wheels exceeds the rotation speed of the front wheels, the vane pump rotates in the reverse direction, and the flow direction of the hydraulic oil is the same as in the reverse running state. When the front wheel and the rear wheel are simultaneously driven by reducing the pressure loss of the orifice, reducing the load generated by the vane pump, and reducing the driving force transmitted from the unlocked rear wheel to the locked front wheel. Locking prevents vehicle behavior from becoming unstable.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

1 to 10 show a first embodiment of the present invention. FIG. 1 is a skeleton diagram of a power transmission device of a four-wheel drive vehicle, and FIG. 2 is a longitudinal sectional view of a hydraulic coupling device. 3 is a sectional view taken along line 3-3 in FIG. 2, and FIG.
5 is a sectional view taken along line 5-5 in FIG. 4, FIG. 6 is a sectional view taken along line 6-6 in FIG. 4, FIG. 7 is a sectional view taken along line 7-7 in FIG. 4, and FIG. FIG. 9 is a graph explaining the operation of the orifice, and FIG. 10 is a hydraulic circuit diagram of the hydraulic coupling device.

As shown in FIG. 1, a four-wheel drive vehicle V includes an engine E disposed horizontally in front of a vehicle body and an engine E
And a transmission M coupled to the right side surface of the transmission.
First power transmission system D1 that transmits the driving force of transmission M to left and right front wheels WFL and WFR as main driving wheels.
Is composed of a first spur gear 2 provided on the output shaft 1 of the transmission M, a second spur gear 3 meshing with the first spur gear 2, a bevel gear type front differential 4 driven by the second spur gear 3, and a front differential 4. Extend left and right to front wheels WFL, WFR
And left and right axles 5L and 5R.

A second power transmission system D2 for transmitting the driving force of the first power transmission system D1 to the left and right rear wheels WRL and WRR as auxiliary driving wheels includes a third spur gear 6 provided in a differential box of the front differential 4. A fourth bevel gear 7 that meshes with the third spur gear 6, a first bevel gear 8 that rotates integrally with the fourth spur gear 7, a second bevel gear 9 that meshes with the first bevel gear 8, and a second bevel gear 9 at the front end. Propeller shaft 10 extending to the rear of the vehicle
f, a rear propeller shaft 10r, a third bevel gear 11 provided at a rear end of the rear propeller shaft 10r,
A fourth bevel gear 12 meshing with the third bevel gear 11,
A bevel gear-type rear differential 14 driven by a fourth bevel gear 12, left and right axles 13L and 13R extending from the rear differential 14 to the left and right and connected to rear wheels WRL and WRR, a front propeller shaft 10f and a rear propeller shaft And a hydraulic coupling device H disposed between 10r.

Next, the structure of the hydraulic coupling device H will be described with reference to FIG.

The hydraulic coupling device H disposed between the front propeller shaft 10f and the rear propeller shaft 10r is configured by connecting a substantially disc-shaped first casing 21 and a substantially cup-shaped second casing 22 with a clip 23. Pump casing 24.
The first side plate 3 is provided inside the second casing 22.
The cam ring 31, the second side plate 32, and the first casing 21 are housed in a stacked state and are integrally fastened with a plurality of bolts. And the first casing 2
A seal member 25 provided on the outer peripheral surface of the first casing 22 seals the space between the second casing 22 and the inner peripheral surface.

The rotor shaft 27 housed inside the pump casing 24 has a needle bearing 28 provided on the inner peripheral surface of the second side plate 32 and a ball bearing 29 provided on the inner peripheral surface of the second casing 22. It is rotatably supported via The rotor 35 housed in the space surrounded by the cam ring 31 and the first and second side plates 30 and 32 is connected to the outer periphery of the rotor shaft 27 by a spline connection part 36.

A seal member 37 fitted in an annular seal groove 27a formed on the outer peripheral surface of the rotor shaft 27.
Is brought into contact with the inner peripheral surface of the shaft hole 22a of the second casing 22 so that the sealing action between the first and second casings 21 and 22 by the sealing member 25 allows the pump casing 24 to move out of the pump casing 24. The outflow of hydraulic oil is prevented, and the inflow of air into the pump casing 24 is prevented. As described above, since the seal groove 27a is formed on the rotor shaft 27 side to hold the seal member 37, the processing of the seal groove 27a is facilitated, and the processing cost can be reduced. If a seal groove is to be formed on the casing side as in the prior art, a complicated boring process is required, and the processing cost increases.

Next, the structure of the vane pump P will be described in detail with reference to FIGS.

As is apparent from FIGS. 2 to 5, the vane pump P housed inside the pump casing 24 includes a first side plate 30, a cam ring 31, a second side plate 32, a rotor 35, and a rotor shaft 27. The first side plate 30, the cam ring 31, and the second side plate 32 are fixed to the first casing 21 with bolts 34. The inner peripheral surface of the cam ring 31 is substantially triangular, and is spaced apart from the circular rotor 35 housed therein by 120 ° in the circumferential direction.
A plurality of working chambers 40 are formed. Plate-like vanes 41 are slidably supported by eight vane grooves 35a radially formed on the rotor 35, respectively.
The outer ends in the radial direction of 1 are in sliding contact with the inner peripheral surface of the cam ring 31. Each vane 41 is provided on the front surface of the second side plate 32.
An annular vane push-up port 32a is recessed so that the radially outer end of the cam ring 31 is in close contact with the inner peripheral surface of the cam ring 31. The vane lifting ports 32a communicate with the bottoms of the eight vane grooves 35a of the rotor 35, respectively. Each vane 41
A coil spring 42 is contracted between the bottom of the vane grooves 35a and the radially inner end of the vane 41 so that the outer end of the vane 41 is in close contact with the inner peripheral surface of the cam ring 31.

As clearly shown in FIGS. 3 to 7, the front surface of the second side plate 32 (the cam ring 31 and the rotor 3
5), in addition to the vane lifting port 32a, three suction ports 43 and 3 facing the circumferential ends of the three working chambers 40 of the vane pump P, respectively.
The discharge ports 44 are recessed. Inhalation port 43 ...
And the discharge ports 44 are formed with a communication hole h1 penetrating the second side plate 32, a communication groove g1 formed in a rear surface of the second side plate 32 (a surface facing the first casing 21), and Communicate with the vane push-up port 32a through a communication hole h2 penetrating the side plate 32.
Stepped valve seats 45 are formed in the communication holes h1.
The check balls 47 mounted on the communication holes h1 from the rear side of the second side plate 32 and the valve seats 45 form check valves 47. The check valves 47 are provided with suction ports 43 and discharge ports 44.
It has a function of permitting the flow of hydraulic oil from the side to the vane lifting port 32a and preventing the flow of hydraulic oil in the opposite direction. The check balls 46 are prevented from falling out of the communication holes h1 by the first casing 21.

Therefore, when the vehicle is traveling forward, the discharge port 4
4 ... becomes high pressure and the suction ports 43 ... become low pressure,
The discharge pressure of the discharge ports 44 on the high pressure side is transmitted to the vane lifting port 32a. When the suction ports 43 become high pressure and the discharge ports 44 become low pressure during the backward running of the vehicle, the discharge pressure of the suction port 43 on the high pressure side is transmitted to the vane lifting port 32a.

Three suction ports 43 and three discharge ports 44 recessed on the front surface of the second side plate 32.
Are communication holes h3 passing through the second side plate 32 ...
And a communication groove g recessed in the rear surface of the second side plate 32
2 and a communication hole h4 passing through the second side plate 32
.. Communicate with the outer peripheral portion of the rotor shaft 27.
Stepped valve seats 48 are formed in the communication holes h4.
The check valves 50 are formed by the check balls 49 mounted on the communication holes h4 from the rear side of the second side plate 32 and the valve seats 48. The check valves 50 are provided with suction ports 43 and discharge ports 44.
It has a function of preventing the flow of hydraulic oil from the side to the outer peripheral portion of the right rotor shaft 27 and allowing the flow of hydraulic oil in the opposite direction. The check balls 49 are prevented from falling out of the communication holes h4 by the first casing 21.

Therefore, when the suction ports 43 (or discharge ports 44) become negative pressure with the operation of the vane pump P, the check valves 50 are opened by the negative pressure and the suction ports 43 (or Since the discharge ports 44 communicate with the reservoir 55 described later, it is possible to reliably prevent the occurrence of cavitation due to excessive negative pressure.

Six L-shaped communication grooves g3 are formed in the rear surface of the second side plate 32, and one end of each of the communication grooves g3 is connected to the suction port 43 through the communication hole h3. And discharge ports 44. Also, three communication grooves g4 are recessed in the front surface of the second side plate 32, and both ends of each communication groove g4 are formed through communication holes h5 penetrating through the second side plate 32 in the L-shape. Communicate with the other ends of the communication grooves g3.

As shown clearly in FIG. 8, orifices 51 are provided in the communication holes h5, respectively. The orifices 51, 51 have directionality. When the hydraulic oil flows in the direction indicated by the arrow in FIG. 8 during forward running of the vehicle, a large pressure loss occurs, and when the vehicle runs backward, the hydraulic oil flows in the opposite direction. A small pressure loss occurs when flowing.

In this manner, the communication holes h1,..., H2..., H3.
And a communication groove g1 formed in the rear surface of the second side plate 32
, G2, g3, and the communication groove g4 formed on the front surface of the second side plate 32, all the oil passages of the vane pump P are formed, and these oil passages are concentrated on the second side plate 32. Is done. As a result, not only can the first side plate 30 be composed of a simple plate, but also the oil passage can be shortened and the number of assembly steps can be reduced by subassembly of the second side plate 32. The size of the hydraulic coupling device H can be reduced. In particular, the communication grooves g1,..., G2,.
Is formed, leakage of hydraulic oil from the side surface of the rotor 35 can be suppressed.

The check valves 47 are arranged inside the communication holes h1 of the second side plate 32, and the check valves 50 are arranged inside the communication holes h4 of the second side plate 32. 47…, 5
.. Can be compactly assembled to the second side plate 32, and the leakage of hydraulic oil can be effectively suppressed. In particular, the amount of hydraulic oil leaking from the side surface of the rotor 35 can be significantly reduced as compared with a conventional one in which the function of the check valves 47 is provided by a switching valve facing the side surface of the rotor 35. Furthermore, the communication holes h1... H2.
h3 ..., h4 ..., h5 ... and communication grooves g1 ..., g2 ...,
g3,..., g4 are all formed in the thickness direction (axial direction of the rotor shaft 27).
2 can be manufactured by sintering, which can contribute to cost reduction.

Since the two orifices 51 are arranged in series two by two, the required pressure loss can be generated even if the diameter of the orifices 51 is increased, and the clogging of the orifices 51 by foreign matters is effectively prevented. In addition to this, it is possible to facilitate the drilling and improve the productivity.

As shown in FIG. 2, a through hole 27b extending in the axial direction is formed inside the rotor shaft 27, and the reservoir 55 is housed therein. Reservoir 55
Is composed of a tubular elastic body 56 formed of thin rubber and filled with air, and a stepped cylindrical closing member 57 fitted into one end opening. Reservoir 55
Is inserted from the front end of the through hole 27b of the rotor shaft 27, and the closing member 57 of the reservoir 55 is inserted into the through hole 27b.
Is fixed, for example, by press-fitting. At this time, the open end of the cylindrical elastic body 56 is sandwiched between the small diameter portion 57a of the closing member 57 and the step portion 27c of the through hole 27b, thereby fixing the reservoir 55 and sealing the cylindrical elastic body 56. And sealing of the through hole 27b are achieved at the same time.

The front end of the rotor shaft 27 has a large diameter.
Are connected to the rear end of the front propeller shaft 10f with bolts 63. A bolt 64 inserted from the coupling 62 side is used to prevent the spline joint 61 between the rotor shaft 27 and the shaft portion 62a of the coupling 62 from coming off.
Into the through hole 27b.

As described above, the reservoir 55 is immovably supported in the through hole 27b of the rotor shaft 27,
Since the inner peripheral surface of the through hole 27b is sealed by the closing member 57, the pump casing 24 can be passed through the threaded portion of the bolt 64 or the spline coupling portion 61 without sealing the inner peripheral surface of the through hole 27b with a special sealing member. Outflow of hydraulic oil and inflow of air into the pump casing 24 can be prevented.

When the hydraulic oil inside the pump casing 24 expands and contracts in response to a temperature change, the volume of the reservoir 55 changes to absorb the change in the volume of the hydraulic oil. Air mixing can be prevented. In particular, since the reservoir 55 is disposed by using the through hole 27b of the rotor shaft 27, it is possible to avoid an increase in the size of the vane pump P due to the provision of the reservoir 55, and furthermore, the discharge pressure of the vane pump P is directly controlled by the reservoir 55.
Can be prevented.

A rear propeller shaft 10r integral with the third bevel gear 11 is supported by a housing 65 of the rear differential 14 via a roller bearing 66, and a coupling 68 fixed to the first casing 21 by bolts 67. The rear propeller shaft 10
r are joined by a spline joint 69 and fixed by a nut 70.

FIG. 10 shows a hydraulic circuit of the hydraulic coupling device H. As can be seen from the figure, the suction port 43 and the discharge port 44 of the vane pump P communicate with each other through orifices 51 provided in the second side plate 32. A high pressure side of the suction port 43 and the discharge port 44 of the vane pump P is connected to a check valve 47 provided on the second side plate 32.
.. Communicate with the vane lifting port 32a. One of the suction ports 43 and the discharge ports 44 of the vane pump P communicates with the reservoir 55 via a check valve 50 provided on the second side plate 32. Further, a relief valve 59 and a choke 60 are provided between the vane lifting port 32a and the reservoir 55. The relief valve 59 is a virtual one, and is constituted by a gap generated between the first side plate 30 and the second side plate 32 and the rotor 35 when the second side plate 32 bends by hydraulic pressure. The choke 60 is also virtual, and is constituted by the gap between the sliding portions between the first side plate 30 and the second plate 32 and the rotor 35.

Next, the operation of the embodiment of the present invention having the above configuration will be described.

When the vehicle V is traveling at a constant speed, the driving force of the engine E is transmitted from the output shaft 1 to the left and right front wheels WFL via the first spur gear 2, the second spur gear 3, the front differential 4, and the left and right axles 5L and 5R. , WFR. At this time, the rotation of the third spur gear 6 of the front differential 4 rotates the rotor shaft 27 of the vane pump P of the hydraulic coupling device H via the fourth spur gear 7, the first bevel gear 8, the second bevel gear 9, and the front propeller shaft 10f. And transmitted to the rotor 35. On the other hand, the rear wheels WRL, WRR driven by the frictional force received from the road surface as the vehicle V travels rotate from the left and right axles 13L, 13R from the rear differential 14, the fourth bevel gear 12, the third bevel gear 11, and the like.
And transmitted to the cam ring 31 of the vane pump P via the rear propeller shaft 10r. Front wheels WFL, WF
No slip has occurred in R, so the front wheels WFL, W
When the rotational speeds of the FR and the rear wheels WRL, WRR are equal, the rotational speed of the rotor 35 matches the rotational speed of the cam ring 31, and no relative rotation occurs. As a result, since the vane pump P does not discharge the hydraulic oil, the hydraulic coupling device H does not transmit the driving force, and the vehicle V enters the front wheel drive state.

The front wheels WFL, WFR to which the driving force of the engine E directly acts upon starting or sudden acceleration on a low friction road.
Slips, the rotor 35 of the vane pump P interlocked with the rotation of the front wheels WFL, WFR, and the rear wheels WRL, WRR
The rotation of the vane pump P relative to the cam ring 31 is interlocked with the rotation of the vane pump P, and the vane pump P receives the hydraulic oil discharged from the discharge ports 44.
More inhalation. Hydraulic oil discharged from the discharge ports 44 passes through the orifices 51 and returns to the suction ports 43. However, the flow resistance at that time generates a load on the vane pump P. WRL,
It is transmitted to WRR. Thus, when the front wheels WFL, WFR slip, the vehicle is in the four-wheel drive state, and the traction of the vehicle V can be increased. At this time, the orifice 5
The load on the vane pump P increases and the driving force transmitted to the rear wheels WRL, WRR increases as the diameter of the wheels 1 decreases.

As described above, when starting or suddenly accelerating on a low friction road, the rotational speeds of the front wheels WFL, WFR are changed to the rear wheels WRL, WRL.
When the rotation speed exceeds the rotation speed of the WRR, the rotor 35 relatively rotates in the normal rotation direction (the direction of arrow A in FIG.
The hydraulic oil is sucked in from the... And the hydraulic oil is discharged from the discharge ports 44. As a result, the check valves 47 connected to the high-pressure discharge ports 44 are opened, so that the high-pressure discharge ports 44 communicate with the vane push-up port 32a, and the vane push-up port 32a and the low-pressure suction port 43. Are interrupted by check valves 47 connected to the suction ports 43. Thus, the hydraulic pressure transmitted to the vane push-up port 32 a urges the vanes 41 radially outward, so that the tips thereof can be pressed against the inner peripheral surface of the cam ring 31.

On the other hand, when the vehicle performs sudden braking, AB
The front wheels WFL, WFR are controlled by controlling the locked state of the wheels by S (antilock brake system) or the like.
Are locked before the rear wheels WRL, WRR, so that the vehicle behavior is stabilized. When the rotational speeds of the rear wheels WRL, WRR exceed the rotational speeds of the front wheels WFL, WFR due to the rapid braking, the rotor 35 relatively rotates in the reverse direction (the direction of the arrow B in FIG. 3) and operates from the discharge ports 44. The oil is sucked and the working oil is discharged from the suction ports 43. As a result, the check valves 47 connected to the high pressure side suction ports 43 are opened, so that the high pressure side suction ports 43 communicate with the vane lifting port 32a, and the vane lifting port 32a and the low pressure side discharge port 44. Are interrupted by check valves 47 connected to the discharge ports 44. Thus, the hydraulic pressure transmitted to the vane push-up port 32 a urges the vanes 41 radially outward, so that the tips thereof can be pressed against the inner peripheral surface of the cam ring 31.

In the four-wheel drive vehicle V equipped with the hydraulic coupling device H, the front wheels WFL, WFR
The vane pump P generates a load according to the relative rotation speed difference between the rear wheels WRL and WRR, and the driving force is transmitted from the side where the rotation speed of the front wheels WFL and WFR and the rear wheels WRL and WRR is higher to the side where the rotation speed is lower. You. Therefore, if the front wheels WFL, WFR try to lock first by controlling the braking force at the time of sudden braking, the rotational speeds of the rear wheels WRL, WRR become equal to those of the front wheels WFL.
The driving force is transmitted from the rear wheels WRL, WRR to the front wheels WFL, WFR beyond the rotation speeds of the FL, WFR, and the locking of the front wheels WFL, WFR is suppressed, so that the rear wheels WR
Since the locking of L and WRR is promoted, in the worst case, the front wheels WFL and WFR and the rear wheels WRL and WRR may be locked simultaneously and the vehicle behavior may become unstable.

In order to avoid this, in this embodiment, the front wheels WF
The magnitude of the load generated by the vane pump P is made different depending on the direction of the relative rotation of the rear wheels LRL, WFR and the rear wheels WRL, WRR. That is, when the rotation speeds of the front wheels WFL, WFR exceed the rotation speeds of the rear wheels WRL, WRR, such as when starting or suddenly accelerating on a low friction road, the rotor 3
5 rotate relative to each other in the direction of arrow A in FIG. 3, and hydraulic oil flows through the pair of orifices 51 in the direction indicated by the arrow in FIG . As a result, the vane pump P generates a large load and moves from the front wheels WFL, WFR to the rear wheels WRL,
The driving force transmitted to the WRR increases (see the solid line in FIG. 9A).

On the other hand, as in the case of sudden braking described above, the rear wheels WR
When the rotation speeds of L and WRR exceed the rotation speeds of the front wheels WFL and WFR, the rotor 35 relatively rotates in the direction of arrow B in FIG. 3 and the hydraulic oil moves the pair of orifices 51. Flow in the opposite direction to generate a small pressure loss.
As a result, the vane pump P generates a small load, and the driving force transmitted from the rear wheels WRL, WRR to the front wheels WFL, WFR decreases (see the broken line (B) in FIG. 9). Thus, the front wheels WFL, WFR can be locked prior to the rear wheels WRL, WRR at the time of sudden braking, and the vehicle behavior can be prevented from becoming unstable.

Also, as an effect peculiar to the first embodiment, the front propeller shaft 1 in which the rotor shaft 27 of the vane pump P is interlocked with the front wheels WFL and WFR as the main drive wheels.
0f, the front wheels WFL, WFR slip, and at the same time, the rotation speed of the rotor 35 increases and the vanes 4
Increase the centrifugal force, and when the vane pump P is started, the sealing performance between the vanes 41 and the cam ring 31 can be improved to improve the responsiveness.

Next, a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the orifices 51, 51 forming a pair of the vane pumps P are symmetrically arranged, so that the characteristics of the hydraulic coupling device H at the time of normal rotation and at the time of reverse rotation can be made equal.

FIG. 12 shows a third embodiment of the present invention, and corresponds to FIG. 2 showing the first embodiment.

In the third embodiment, the mounting direction of the vane pump P is opposite to that of the first embodiment, and the first side plate 30 and the cam ring 31 are provided on the front propeller shaft 10f side.
And the second side plate 32, and the rotor shaft 27 and the rotor 35 are connected to the rear propeller shaft 10r side. That is, the coupling 62 is coupled with the coupling 68 coupled to the rear propeller shaft 10r by the spline coupling portion 69 with the bolts 63, and the shaft 62a of the coupling 62 is inserted into the through hole 27b of the rotor shaft 27. It is joined to the circumference by a spline joint 61. Also the front propeller shaft 10
f is connected to the first casing 21 by bolts 67.

Also in the present embodiment, the cam ring 31 and the rotor 35 are rotated relative to each other by the relative rotation of the front wheels WFL, WFR and the rear wheels WRL, WRR, so that the vane pump P operates. The four-wheel drive function can be exhibited in the same manner as described above, and the effect of the reservoir 55 is the same as that of the first embodiment. However, the following special effects can be obtained by mounting the vane pump P upside down with respect to the first embodiment.

That is, when a plurality of centrifugal valves are radially provided on the rotor 35 and the rotation of the rotor 35 increases during high-speed running, the centrifugal valve opens to switch the vane pump P to a no-load state. In order to open the centrifugal valve, the rotation speed of the rotor 35 is set to the front wheel W which is the main drive wheel.
It is necessary not to be affected by the slip of FL and WFR. Therefore, if the rotor 35 is assumed to be the front wheels WFL, WF
R, the front wheels W even if the vehicle speed is lower than the set vehicle speed
There is a problem that the centrifugal valve opens when the rotation speed increases due to slippage of the FL and WFR. However, if the rotor 35 is connected to the rear drive wheels WRL and WRR as in the embodiment, The above problem can be solved.

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.

[0056]

As described above, according to the first aspect of the present invention,

[Brief description of the drawings]

FIG. 1 is a skeleton diagram of a power transmission device of a four-wheel drive vehicle.

FIG. 2 is a longitudinal sectional view of a hydraulic coupling device.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 2;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 2;

FIG. 6 is a sectional view taken along line 6-6 in FIG. 4;

FIG. 7 is a sectional view taken along line 7-7 of FIG. 4;

8 is a sectional view taken along line 8-8 in FIG. 4;

FIG. 9 is a graph illustrating the operation of an orifice.

FIG. 10 is a hydraulic circuit diagram of a hydraulic coupling device.

FIG. 11 is a view corresponding to FIG. 8 according to a second embodiment of the present invention.

FIG. 12 is a view corresponding to FIG. 2 according to a third embodiment of the present invention.

[Explanation of symbols]

 10f Front propeller shaft (input shaft) 10r Rear propeller shaft (output shaft) 21 First casing (casing) 30 First side plate (side plate) 31 Cam ring 32 Second side plate (side plate) 32a Vane push-up port 35 Rotor 41 Vane 43 Suction port 44 Discharge port 45 Valve seat 46 Check ball 47 Check valve 48 Valve seat 49 Check ball 50 Check valve 51 Orifice 55 Reservoir E Engine P Vane pump WFL Left front wheel (main driving wheel) WFR Right front wheel (main driving wheel) WRL Left rear wheel (sub-drive wheel) WRR Right rear wheel (sub-drive wheel) g1 communication groove g2 communication groove g3 communication groove (second communication groove) g4 communication groove (first communication groove) h1 communication hole (first communication hole) h2 communication hole (second communication hole) h Communication hole (first communication hole) h4 hole (second communication hole) h5 hole (second communication hole)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Kazunori Miyata 19, Matsuyama-cho, Moka-shi, Tochigi Honda Motor Co., Ltd.Tochigi Seisakusho Co., Ltd. F term (reference) 3D043 AA05 AA06 AB02 AB17 EA03 EA11 EA38 EA42 EB06 EB13 EC01 EC02 EC05 EE07 EF06 EF17 EF24 3H040 AA03 BB05 BB11 CC03 CC16 DD03 DD06 DD07 DD21 DD27 DD28 DD33

Claims (4)

[Claims] An input shaft (10f) driven by an engine (E) together with left and right main drive wheels (WFL, WFR).
An output shaft (10r) that rotates with the left and right auxiliary drive wheels (WRL, WRR); a vane pump (P) that operates according to a relative rotational speed difference between the input shaft (10f) and the output shaft (10r); And an orifice (51) provided between the suction port (43) and the discharge port (44) of the (P). The vane pump (P) comprises a cam ring (31) and a pair of side plates (30, A rotor (35) is housed in a space surrounded by 32), and radially outer ends of a plurality of vanes (41) slidably supported in the rotor (35) are slidably contacted with a cam ring (31). Any one of the high pressure side port of the suction port (43) and the discharge port (44) is connected to the annular vane push-up port (32a) facing the radially inner end of the vane (41) through a communication passage. In a power transmission device for a four-wheel drive vehicle provided with a check valve (47) that is in communication with the communication passage and that allows only the flow of hydraulic oil from the high-pressure side port to the vane push-up port (32a), the casing (21) A suction port (43), a discharge port (44), and a vane push-up port (32a) are formed on the inner surface of one side plate (32) having an outer surface in contact with the side plate (32). A communication groove (g1) formed in the outer surface, a first communication hole (h1) penetrating through the side plate (32) and communicating the communication groove (g1) with the suction port (43) and the discharge port (44);
A second communication hole (h2) penetrating the side plate (32) to communicate the communication groove (g1) with the vane push-up port (32a), and the check valve (47) is connected to the first communication hole (h1). The check ball (46) is inserted into the valve seat (45) formed on the outer side of the side plate (32).
A power transmission device for a four-wheel drive vehicle, comprising: 2. An input shaft (10f) driven by an engine (E) together with left and right main drive wheels (WFL, WFR).
An output shaft (10r) that rotates with the left and right auxiliary drive wheels (WRL, WRR); a vane pump (P) that operates according to a relative rotational speed difference between the input shaft (10f) and the output shaft (10r); And an orifice (51) provided between the suction port (43) and the discharge port (44) of the (P). The vane pump (P) comprises a cam ring (31) and a pair of side plates (30, A rotor (35) is housed in a space surrounded by 32), and radially outer ends of a plurality of vanes (41) slidably supported in the rotor (35) are slidably contacted with a cam ring (31). One of the low pressure side port of the suction port (43) and the discharge port (44) communicates with the reservoir (55) via a communication passage, and the low pressure side port communicates with the communication passage from the reservoir (55). In a power transmission device for a four-wheel drive vehicle provided with a check valve (50) that allows only the flow of hydraulic oil to the side port, the inner surface of one side plate (32) whose outer surface is in contact with the casing (21) And a communication groove (g2) formed on the outer surface of the side plate (32), and a communication groove penetrating the side plate (32). (G2) communicates with the suction port (43) and the discharge port (44) through the first communication hole (h3) and the side plate (32) to communicate the communication groove (g2) with the reservoir (55). A valve seat (48) comprising a second communication hole (h4) and the check valve (50) formed in the second communication hole (h4).
A power transmission device for a four-wheel drive vehicle, characterized in that a check ball (49) is mounted on the side plate (32) from the outer surface side. 3. An input shaft (10f) driven by an engine (E) together with left and right main drive wheels (WFL, WFR).
An output shaft (10r) that rotates with the left and right auxiliary drive wheels (WRL, WRR); a vane pump (P) that operates according to a relative rotational speed difference between the input shaft (10f) and the output shaft (10r); And an orifice (51) provided between the suction port (43) and the discharge port (44) of the (P). The vane pump (P) comprises a cam ring (31) and a pair of side plates (30, A rotor (35) is housed in a space surrounded by 32), and radially outer ends of a plurality of vanes (41) slidably supported in the rotor (35) are slidably contacted with a cam ring (31). In a power transmission device for a four-wheel drive vehicle, a suction port (43), a discharge port (44) and a discharge port (44) are formed on the inner surface of one side plate (32) having an outer surface in contact with a casing (21). Beauty second communication groove on the outer surface of the side plate (32) to form a first communicating groove (g4) (g
3) is formed, and the suction port (43) and the discharge port (44) are connected to the second communication groove (g3) through the first communication hole (h3) penetrating the side plate (32). 32), the second communication groove (g3) is connected to the first communication groove (g4) by a pair of second communication holes (h5), and the orifices (5) are respectively connected to the pair of second communication holes (h5).
A power transmission device for a four-wheel drive vehicle, characterized in that 1) is formed. 4. The orifice (51) has a large pressure loss in a direction in which hydraulic oil flows when the vehicle travels forward,
4. The power transmission device for a four-wheel drive vehicle according to claim 3, wherein the power transmission device has a shape in which a pressure loss in a direction in which hydraulic oil flows when the vehicle travels backward is reduced.