JP2815731B2 - Hydraulic power transmission coupling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic power transmission coupling used for distributing driving force of a vehicle.

[0002]

2. Description of the Related Art The present applicant has proposed the following hydraulic power transmission coupling in Japanese Patent Application No. 02-37921 (Japanese Patent Application Laid-Open No. 3-239824). That is, the hydraulic power transmission coupling is provided between a relatively rotatable input / output shaft, is connected to the one shaft, and has a cam housing having a cam surface having two or more peaks on an inner surface thereof; And a rotor member rotatably housed in the cam housing and forming a plurality of plunger chambers, and reciprocatingly moved by receiving a return spring from each of the plurality of plunger chambers. A plurality of plungers that are housed freely and are driven by the cam surface when the two shafts rotate relative to each other, and a suction and discharge hole that opens on the surface of the rotor member and communicates with the plunger chamber,
While rotatably slidingly contacting the surface of the rotor member,
When the relative rotation directions of the two shafts are switched, the valve body is positioned so as to be rotatable by a predetermined angle with the cam housing, and acts as a suction valve or a discharge valve depending on a positional relationship with the suction and discharge holes. And means for generating a flow resistance by receiving a discharge pressure by driving the plunger, and transmitting a torque corresponding to a rotational speed difference between the two shafts.

[0003]

However, in such a conventional hydraulic power transmission coupling, as shown in FIGS. 10 and 11, a suction port 53 communicating with a suction and discharge hole 52 of a rotor 51 is provided. Discharge port 54, suction path 55
An orifice 58 is provided in the valve body 57 having the communication groove 56 and the torque transmission characteristic with respect to the rotation difference of the joint does not change even if the rotation direction changes. Therefore, A
When the joint is applied to the place where the power from the engine of the 4WD vehicle with BS is transmitted to the front shaft or the rear shaft, the AB
When S operates, it is difficult to allow a large rotation difference between the front wheel and the rear wheel, and this will interfere with the ABS characteristics.

On the other hand, there has been proposed a joint in which torque transmission characteristics are provided only on the drive side and torque characteristics are lost on the reverse rotation side. However, such joints are AB
Although it is possible to avoid interference with the S, when the vehicle retreats, it becomes a two-wheel drive vehicle and cannot exhibit the characteristics of a 4WD vehicle.

The present invention has been made in view of such a conventional problem. The characteristics at the time of forward movement show what has been required in the past as they are, and when the ABS is operated, the joint does not greatly interfere with the operation of the ABS. It is an object of the present invention to provide a hydraulic power transmission joint capable of retaining the characteristic of 4WD by reducing the characteristic of the hydraulic power transmission coupling.

[0006]

In order to achieve the above object, the present invention is provided between input / output shafts which are rotatable relative to each other,
A cam housing connected to the one shaft and having a cam surface having two or more peaks on an inner surface; and a plurality of plans connected to the other shaft and rotatably housed in the cam housing. A rotor forming a jar chamber;
Each of the plurality of plunger chambers is housed in a reciprocating manner under the pressure of a return spring, and is formed in the plurality of plungers driven by the cam surface when the two shafts rotate relative to each other, and formed in the rotor. A suction and discharge hole communicating with the plunger chamber, rotatably slidingly contacting the surface of the rotor, and positioning rotatably by a predetermined angle with the cam housing when a relative rotation direction of the two shafts is switched. A valve body that acts as a suction valve or a discharge valve depending on the positional relationship with the suction / discharge port; and a unit that generates flow resistance by the flow of discharge oil by driving the plunger. In a hydraulic power transmission coupling for transmitting a torque corresponding to a difference, a flow resistance generating means that opens when the rotor rotates forward and closes when the rotor rotates reversely. And a small-diameter orifice and a large diameter orifice as flow resistance generating means for opening during and closed porosity during forward rotation of the rotor reverses, and is formed in the valve body.

[0007]

The present invention, as shown in FIG. 6, has a function when used at a point E of a four-wheel drive vehicle with an ABS, that is, between a transfer device 62 of a transmission 61 and a differential 66 on a rear wheel 65 side. Demonstrate. When such a vehicle slips easily on a snowy road or the like, when a sudden brake is applied, a difference in rotation occurs between a vehicle in which the rotation of the tire is locked and a vehicle in which the tire rotates according to the road surface condition.

[0008] This difference in rotation occurs between the left and right wheels,
It escapes at the differential, but the difference between the average rotation of the front two wheels and the average rotation of the rear two wheels must be escaped at the joint. On this occasion,
The braking force is transmitted through the joint from the slower to the faster of the respective average rotational speeds. This becomes interference, and A of each wheel
In order to make it difficult to control the rotation by the BS system, the joint must be
It is desirable that the connection characteristics be small.

For this reason, according to the present invention, the characteristics of the joint are set such that there is no feeling of tight corner braking as a 4WD vehicle and no slipping feeling on snowy roads, muddy terrain, etc. during normal forward movement. However, at the time of braking, in order to avoid the interference, the direction of transmission of the driving force on the input side is detected, the valve body rotates, and the torque transmission characteristic is loosened.

On the other hand, since the rotational difference generated by the ABS is limited and is not so large, a structure capable of transmitting torque where the rotational difference is large is provided so that a four-wheel drive vehicle can be used even when the vehicle retreats. The characteristic of can be utilized. That is, at the time of normal rotation of the rotor, the small-diameter orifice is opened and the large-diameter orifice is closed. The torque characteristic at this time is a normal torque characteristic as shown in FIG.

On the other hand, when the rotor rotates in the reverse direction, the small-diameter orifice closes and the large-diameter orifice opens. The torque characteristic at this time is shown in FIG. If the rotation difference is less than the required rotation difference C of the ABS, the average torque D
The torque can be reduced as follows. When the rotation difference is equal to or larger than the necessary rotation difference C of the ABS, a torque equal to or larger than the interference torque D to the ABS is transmitted. Thus, at the time of ABS operation,
It is possible to avoid interference with the ABS and make use of the torque characteristics of a 4WD vehicle when reversing.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 are views showing one embodiment of the present invention.
First, the configuration will be described. In FIG. 1 and FIG.
Is a cam having a cam surface 2 having two or more peaks on an inner surface thereof. The cam 1 is connected to an output shaft 3 and rotates integrally with the output shaft 3. The cam 1 is fixed to the cam housing 4, and the cam housing 4 rotates integrally with the cam 1.

A rotor 5 is rotatably housed in the cam housing 4. The rotor 5 is connected to an input shaft 6,
It rotates integrally with the input shaft 6. A plurality of plunger chambers 7 are formed in the rotor 5 in the axial direction.
Inside, a plurality of plungers 8 are slidably accommodated via return springs 9. Further, a plurality of suction / discharge holes 10 are formed in the rotor 5 so as to communicate with each plunger chamber 7.

Reference numeral 11 denotes a suction port 12 and a suction passage 13 on the surface.
And a rotary valve (valve element) having a discharge port 14 formed therein.
Are formed. The communication groove 15 communicates with the discharge port 14, and a lid member 16 is provided in close contact with the communication groove 15. Reference numerals 17A and 17B denote orifices as flow resistance generating means. The orifices 17A and 17B are formed in the rotary valve 11 in a radial direction so as to communicate the discharge port 14 and the suction passage 13. One orifice 1
7A is formed with a small diameter, and the other orifice 17B is formed with a large diameter.

At the time of normal rotation of the rotor 5, the orifice 17A
Is opened in the notch 18A of the cam housing 4, and the orifice 17B is closed by the projection 18B of the cam housing 4. When the rotor 5 rotates in the reverse direction, the orifice 17A
Is closed by a projection 18B of the cam housing 4, and the orifice 17B is opened in a notch 18A of the cam housing 4.

The rotary valve 11 has a positioning projection 19 which engages with a notch 18A formed on the inner periphery of the cam housing 4. The rotary valve 11 constitutes a timing member for determining the opening / closing timing of the suction / discharge hole 10, and the notch 18 </ b> A and the projection 19 constitute a positioning mechanism for regulating the phase relationship between the cam 1 and the rotary valve 11.

When the plunger 8 is in the suction stroke,
The suction port 12 of the rotary valve 11 and the suction / discharge hole 10 of the rotor 5 have a positional relationship, and oil can be sucked into the plunger chamber 7 through the suction passage 13, the suction port 12, and the suction / discharge hole 10 of the rotor 5. . Also,
When the plunger 8 is in the discharge stroke, the relationship is opposite to that of the suction stroke, and the suction and discharge hole 10 of the rotor 5 communicates with the communication groove 15 via the discharge port 14 of the rotary valve 11,
The suction port 12 is in a closed state.

Reference numeral 20 denotes a thrust block which rotates integrally with the cam housing 4 and supports the input shaft 6 via a bearing 21. A needle bearing 22 is interposed between the thrust block 20 and the rotary valve 11, and the friction torque on the needle bearing 22 side is set to be smaller than the friction torque between the rotor 5 and the rotary valve 11. Therefore, when the direction of the differential rotation changes, the rotary valve 11 rotates together with the rotor 5, and the positioning projection 19 of the rotary valve 11 engages with the notch 18 </ b> A of the cam housing 4.
, And rotate integrally with the cam housing 4. Thus, the suction / discharge port 10 is forcibly opened / closed at a predetermined timing even in the normal rotation or the reverse rotation.

Reference numeral 23 denotes an accumulator piston which rotates integrally with the cam housing 4, and the accumulator piston 23 moves according to the internal pressure. A return spring 25 is interposed between the accumulator piston 23 and the retainer 24. 26 is an oil seal, 2
7 is a stopper ring, 28 is a bolt, 29 is a lubrication hole, 3
0 is a needle bearing.

Next, the operation will be described. Cam 1 and rotor 5
When there is no rotation difference between the plunger 8 and the plunger 8, the plunger 8 does not operate and no torque is transmitted. At this time, the plunger 8 is pressed against the cam surface 2 by the return spring 9. Next, when the rotation of the input shaft 6 having the rotor 5 rotates faster than the output shaft 3 having the cam 1, and a rotation difference is generated between the input and output shafts, the plunger 8 in the discharge stroke becomes 2 pushes in the axial direction.

For this reason, the plunger 8 allows the oil in the plunger chamber 7 to pass through the suction / discharge port 10 through the rotary valve 11.
To the discharge port 14. The oil pushed out to the discharge port 14 is supplied to the suction passage 13 through the communication groove 15 and the orifice 17A. At this time, the orifice 17A
, The hydraulic pressure in the communication groove 15, the discharge port 14, and the plunger chamber 7 increases, and a reaction force is generated in the plunger 8. By rotating the cam 1 against this plunger reaction force, a torque is generated, and the torque is transmitted between the cam 1 and the rotor 5.

At this time, the orifice 17A is open toward the notch 18A, but the orifice 17B is closed by the projection 18B of the cam housing 4. For this reason, the torque characteristic has an A-curve characteristic capable of transmitting a large torque even if the rotation difference is small as shown in FIG. Further, when the cam 1 rotates, a suction stroke occurs, and the suction / discharge port 10 and the suction port 12 communicate with each other. Therefore, oil in the suction passage 13 is sucked into the plunger chamber 7 through the suction port 12 and the suction / discharge port 10, The plunger 8 returns along the cam surface 2 of the cam 1.

When the relative rotation direction between the input and output shafts changes, the rotary valve 11 rotates with respect to the cam housing 4. Therefore, the cam housing 4 and the rotary valve 1
The relative relationship with 1 changes as shown in FIG. As a result, the orifice 17A is closed by the projection 18B, and the orifice 17B is opened in the notch 18A.

The orifice 17B is opposed to the orifice 17B.
Has a slightly larger diameter, and its torque characteristic is as shown by the curve B in FIG. 5, and the interference torque (D,
(See reference). However, even with the characteristic of the curve B, when four-wheel drive torque is required at the time of reverse start, a practically necessary torque can be secured by providing a rotation difference. FIG. 6 shows the location of the joint.

FIGS. 7 to 9 show another embodiment of the present invention. In FIG. 7, 31A and 31B are orifices formed in the rotary valve 11 in the axial direction, and the diameter of the orifice 31B is larger than that of the orifice 31A. Reference numeral 32 denotes a space outside the needle bearing 22, and one of the orifices 31A and 31B is opened in the space 32.

Reference numeral 33 denotes a projection integrally formed with the thrust block 20, and the projections 33 form the orifices 31A, 31A.
1B is closed. Reference numerals 34 and 35 denote plugs for closing holes provided in the rotary valve 11 for processing a hydraulic circuit. As shown in FIG. 8, when the rotor 11 rotates forward, the orifice 31 </ b> A opens in the space 32, and the orifice 31 </ b> B is closed by the projection 33. The torque characteristic at this time is a characteristic indicated by A in FIG.

As shown in FIG. 9, when the rotor 11 rotates in the reverse direction, the orifice 31A is closed by the projection 33, and the orifice 31B is closed in the space 32. The torque characteristic at this time is a characteristic indicated by B in FIG. In this embodiment, the same effect as that of the embodiment can be obtained.

[0028]

As described above, according to the present invention, when the vehicle is moving forward, normal torque characteristics can be obtained, and when the ABS is activated, the torque is reduced to a point where it does not greatly interfere with the ABS operation. Even when the vehicle retreats, the torque characteristics of a 4WD vehicle can be left.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrows AA in FIG. 1;

FIG. 3 is an explanatory diagram of an operation during normal rotation of a rotor.

FIG. 4 is an explanatory diagram of an operation at the time of reverse rotation of a rotor.

FIG. 5 is a graph showing torque characteristics.

FIG. 6 is a diagram showing an example in which the present invention is applied to a vehicle.

FIG. 7 is a diagram showing another embodiment of the present invention.

FIG. 8 is an explanatory diagram of an operation during normal rotation of a rotor.

FIG. 9 is an explanatory diagram of an operation at the time of reverse rotation of the rotor.

FIG. 10 shows a conventional example.

FIG. 11 shows a conventional rotary valve.

[Explanation of symbols]

 1: cam 2: cam surface 3: output shaft 4: cam housing 5: rotor 6: input shaft 7: plunger chamber 8: plunger 9: return spring 10: suction / discharge hole 11: rotary valve 12: suction port 13: Suction path 14: Discharge port 15: Communication groove 16: Lid member 17A, 17B: Orifice 18A: Notch 18B: Projection 19: Projection 20: Thrust block 21: Bearing 22: Needle bearing 23: Accumulator piston 24: Retainer 25: Return Spring 26: Oil seal 27: Stopper ring 28: Bolt 29: Lubrication hole 30: Needle bearing 31A, 31B: Orifice 32: Space 33: Projection

Claims (3)

(57) [Claims] 1. A cam housing provided between input and output shafts rotatable relative to each other and connected to the one shaft and having a cam surface having two or more peaks on an inner surface, and connected to the other shaft. A plurality of plunger chambers rotatably housed in the cam housing, and a plurality of plunger chambers, each of which is reciprocally housed under the pressure of a return spring. A plurality of plungers driven by the cam surface when the two shafts rotate relative to each other; a suction / discharge hole formed in the rotor, which communicates with the plunger chamber; and rotatably slidably contact the surface of the rotor. When the relative rotation direction of the two shafts is switched, it is positioned rotatably by a predetermined angle with the cam housing,
A valve body that acts as a suction valve or a discharge valve depending on the positional relationship with the suction and discharge holes of the rotor; and a unit that generates flow resistance by the flow of discharge oil by driving the plunger. A hydraulic power transmission coupling for transmitting a torque corresponding to the diameter, comprising: a small-diameter orifice as a flow resistance generating means that opens when the rotor rotates forward and closes when the rotor rotates reversely; and closes and reverses when the rotor rotates forward. A hydraulic power transmission coupling, wherein a large-diameter orifice as a flow resistance generating means that is sometimes opened is formed in the valve body. 2. The two orifices are formed radially in the valve body and alternately formed on the inner periphery of the cam housing.
2. The hydraulic power transmission coupling according to claim 1, wherein a hole is opened in a notch of the notch and the protrusion, and the hole is closed by the protrusion. 3. The input shaft according to claim 2, wherein the two orifices are formed in the valve body in an axial direction and rotate integrally with the cam housing.
Characterized in that by opening the space outside the <br/> needle bearing provided between the thrust block and the valve body, is closed porosity by projections formed on the slide <br/> strike block that is supported The hydraulic power transmission coupling according to claim 1, wherein: