JP2989467B2 - 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 applicant of the present invention has proposed, in Japanese Patent Application No. 3-248595, a hydraulic power transmission coupling in which the torque characteristics are changed when the differential direction of the coupling is forward rotation and reverse rotation. I have. That is, the hydraulic power transmission coupling is provided between a relatively rotatable input and 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; Connected to the other axis,
A rotor rotatably housed in the cam housing and having a plurality of plunger chambers formed in the axial direction; and a rotor housed in each of the plurality of plunger chambers so as to be reciprocally movable, and when the two shafts rotate relative to each other. A plurality of plungers driven by the cam surface; a suction / discharge hole opened at one end face of the rotor not containing the plunger and communicating with the plunger chamber; and a rotatable sliding contact with the end face of the rotor. A plurality of suction ports, which are positioned so as to be rotatable at a predetermined angle between the cam housing and a suction port and a discharge valve depending on a positional relationship with the suction and discharge holes, and a valve body having discharge ports formed on a surface thereof; A high-pressure chamber communicating with the discharge port, and means for generating flow resistance at an outlet from the high-pressure chamber to the low-pressure chamber in the joint; In the hydraulic power transmission coupling for transmitting the same torque, two orifices as the flow resistance generating means are provided on the valve body, and a spool-shaped orifice for controlling a conduction state between at least one orifice and the high-pressure chamber. A switching valve is provided, and the cam housing or a member fixed integrally with the cam housing is provided with a cam surface for controlling the operation of the switching valve according to a positional relationship with the valve body.

[0003] The present applicant has filed a Japanese Patent Application No. Hei 5-19804.
No. 8 proposes a hydraulic power transmission coupling that locks only when the differential direction of the coupling is forward rotation. That is,
The hydraulic power transmission coupling is provided between input / output shafts that can rotate relative to each other, is connected to the one shaft, and has a cam housing having a cam surface having a plurality of ridges on an inner surface, and the other shaft. And a rotor, which is rotatably housed in the cam housing and has a plurality of plunger chambers opened on one side surface, and each of the plurality of plunger chambers is pressed by a return spring. A plurality of plungers that are housed reciprocally and driven by the cam housing when the two shafts rotate relative to each other, and that are open at other end surfaces that do not store the plungers of the rotor; A suction / discharge hole communicating with the cam housing and positioned in a predetermined relationship with the cam housing; Suction valve depending on the positional relationship between the discharge hole, a plurality of suction ports to the action of the discharge valve, a valve body formed on the surface of the discharge port, provided inside the valve body,
A collecting chamber for collecting oil discharged from the discharge port; means for generating flow resistance at an outlet of the collecting chamber; and a hydraulic power transmission joint for transmitting torque according to a rotational speed difference between the two shafts. A load conversion mechanism that detects friction torque acting on the valve element by sliding contact with the rotor and converts the load into a load only when the relative rotation direction of the two shafts is one direction; A closing valve for closing the flow resistance generating means, and a spring member for urging the load conversion mechanism with a predetermined load in a direction opposite to the direction of the closing valve.

[0004]

However, such a conventional hydraulic power transmission coupling has no lock mechanism in the former case, so that it has poor running performance on sandy terrain and rough roads, There has been a problem that the joint temperature becomes too high after traveling for a long time. On the other hand, in the latter case, when the vehicle is suddenly moved forward, a large torque is generated when the vehicle is locked, and a large load is applied to the entire drive system. Therefore, it is necessary to use a component that can withstand this, resulting in an increase in cost. . Also,
When applying to an ABS-equipped vehicle, there is a problem that the differential limiting effect on the front and rear wheels is too high and the ABS malfunctions.

[0005] The present invention has been made in view of such a conventional problem, and has a locking mechanism to improve running performance, and even when the locking mechanism operates at the time of sudden start, torque can be reduced by the relief mechanism. It is an object of the present invention to provide a hydraulic power transmission coupling capable of restricting and preventing malfunction of the ABS.

[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 surface connected to the one shaft and having two or more peaks on an inner surface is formed , and a plurality of notches are formed on an inner periphery.
Cam housing and which forms; to each of the plurality of plungers chamber; together are connected to the other shaft, said rotatably housed in a cam housing, a rotor having a plurality of plungers chambers in the axial direction A plurality of plungers housed reciprocally and driven by the cam surface when the two shafts rotate relative to each other; an opening at one end face of the rotor that does not store a plunger, which communicates with the plunger chamber. and suction and discharge hole; together rotatably sliding contact with an end surface of said rotor, said
A pair of positioning engaging the notch of the cam housing
The has a projection of use are given pivotably positioned between the cam housing, a plurality of suction ports to the action of the suction valve and the discharge valve by the positional relationship between the suction and discharge hole, the discharge port surface A high pressure chamber communicating with the formed valve element and the discharge port; and a means for generating a flow resistance at an outlet from the high pressure chamber to the low pressure chamber in the joint; a torque corresponding to a rotational speed difference between the two shafts is provided. in the hydraulic power transmission joint for transmitting, to one of the projections of the valve body, provided with a first orifice as the flow resistance generating means, set the second orifice on the opposite side of the other projection
When the relative rotational direction of the input / output shaft is normal rotation, when the friction rotational force acting on the valve body due to sliding contact with the rotor exceeds a predetermined value, the first orifice is closed and reverse rotation is performed. At the time of forward rotation .
Is closed, and when the pressure in the high-pressure chamber exceeds a predetermined value, the second orifice is opened. When the relative rotation direction of the input / output shaft is reversed, the orifice is brought into contact with the rotor by sliding contact with the rotor. A relief valve is provided for forcibly opening the second orifice when the acting friction torque exceeds a predetermined value.

Further, the present invention has a plate portion for pushing the closing valve, and closes the first orifice during normal rotation when a frictional rotating force stronger than the spring force is applied, and reversely rotates. Sometimes has a first spring member for urging a closing valve to open the first orifice, and a plate portion for pushing the relief valve, and when the spring force is stronger than the hydraulic pressure from the high pressure chamber during normal rotation. A second spring member is provided for closing the second orifice and for urging the relief valve to open the second orifice when the reverse rotation is performed and the friction rotational force is greater than the spring force.

The present invention is characterized in that the spring force of the second spring member is stronger than the spring force of the first spring member.

[0009]

According to the hydraulic power transmission joint of the present invention having such a configuration, one orifice is normally kept open and the friction torque acting on the valve body during normal rotation is maintained at a predetermined value. The orifice is closed only if the value is exceeded. In addition, the other orifice is normally kept closed, and when the pressure in the high-pressure chamber exceeds a predetermined value, the pressure oil is relieved, and the friction torque acting on the valve body at the time of reverse rotation is reduced to a predetermined value. Is exceeded, the other orifice is forcibly opened even if the pressure in the high-pressure chamber is equal to or lower than the relief pressure.

That is, since one orifice is closed by the shut-off valve when the friction torque exceeds a predetermined value at the time of normal rotation, the running performance on sandy ground and rough road is good and the joint temperature does not rise too much. . In addition, even if the lock mechanism works at the time of sudden start, the torque is limited by the relief, so that a large load is not applied to the joint, and at the same time, the strengthening of parts can be omitted, so the cost increases. Is also gone. Furthermore, since the forced relief at the time of reverse rotation works, the torque characteristics can be suppressed to a low level, and malfunction of the ABS can be prevented.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 11 are views showing one embodiment of the present invention. FIG. 6 is a sectional view of a joint according to one embodiment of the present invention. First, the configuration will be described. In FIG. 6, reference numeral 1 denotes 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 (not shown) and rotates integrally with the output shaft. I do. Further, the cam 1 is fixed to the cam housing 4 by the welding portion 3, and the cam housing 4 rotates integrally with the cam 1.

Reference numeral 5 denotes a rotor rotatably housed in the cam housing 4. The rotor 5 is coupled to the 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) formed with a discharge port 14, and a communication groove 15 communicating with each of the discharge ports 14 is formed on the back surface of the rotary valve 11. Further, a lid member 16 is provided on the back surface so as to be in close contact therewith. Here, FIGS. 1 to 5 show the positional relationship between the cam housing 4 and the rotary valve 11.

1 to 5, a plurality of projections 17A and 17B are formed on the inner periphery of the cam housing 4 in the circumferential direction, and notches 18A and 18B are provided between the projections 17A and 17B.
Are formed. The rotary valve 11 has positioning projections 19A and 19B that engage with the notches 18A and 18B of the cam housing 4.

The protrusion 19A of the rotary valve 11 has
A collection chamber 20 is formed as a high-pressure chamber, and the collection chamber 20 communicates with each discharge port 14. A first orifice 22 as a flow resistance generating means is formed laterally at an outlet of the collecting chamber 20. The projection 19A on the outlet side of the first orifice 22 is formed with a discharge oil passage 23 through which oil passing through the first orifice 22 is discharged into the low-pressure chamber in the joint.

A projection 19A is provided with a closing valve 24 concentrically with the first orifice 22 so as to be movable in the axial direction. The closing valve 24 is formed of a rod-shaped member having a spherical or tapered end. A first pressing the closing valve 24 from the outside
The spring member 25 is shown in FIG. In FIG. 7, reference numeral 26 denotes a plate for pressing the closing valve 24, and 27 denotes a stopper for positioning the plate 26 in the return direction. The plate 26 and the stopper 27 are connected to the connecting part 28. You. A curved portion 29 extends from the plate portion 26, and a pin hole 30 is formed at an end of the curved portion 29. Plate part 26, stopper part 27 and connecting part 28
Are arranged so as to surround the projection 19A, the curved portion 29 is provided along the outer peripheral portion of the rotary valve 11, and an end of the curved portion 29 is fixed to the rotary valve 11 by a pin 31. The plate portion 26 and the stopper portion 27 are normally urged by a spring force in a direction in which the closing valve 24 is not pressed.

The shut-off valve 24 pressed by the first spring member 25 has a frictional torque (friction torque) acting on the rotary valve 11 by sliding contact with the rotor 5 when the relative rotation of the input / output shaft is normal rotation. When the pressure exceeds a predetermined value (the spring force of the first spring member 25), the first orifice (one orifice) 22 is closed, and when the friction torque does not act on the closing valve 24, the first orifice 22 is closed. It is always open.

The friction torque acting on the rotary valve 11 is basically proportional to the transmission torque of the joint. A collecting chamber 20 as a high-pressure chamber is formed on the projection 19B opposite to the projection 19A, and the collecting chamber 20 communicates with each discharge port 14. A second orifice 61 as a relief oil passage is formed laterally at the outlet of the collecting chamber 20. A discharge oil passage 62 through which oil passing through the second orifice 61 is discharged to the low-pressure chamber in the joint is formed at the projection 19B on the outlet side of the second orifice 61.

The projection 19B is provided with a relief valve 63 concentrically with the second orifice 61 so as to be movable in the axial direction. The relief valve 63 is formed of a rod-shaped member having a spherical or tapered end. 64 is a second spring member,
The spring member 64 urges the relief valve 63 in a direction to always close. The second spring member 64 has a plate portion 65 for pressing the relief valve 63, similarly to the one shown in FIG.
And a stopper 66 for positioning the plate 65 in the return direction, a connecting portion 67 connecting the plate 65 and the stopper 66, and extending from the plate 65 and fixed by pins 68. It has a curved portion 70 having a pin hole 69.

The relief valve 63 closes the second orifice 61 by the spring force of the second spring member 64 during normal rotation in which no friction torque acts, and the pressure of the collecting chamber 20 reduces the spring force of the second spring member 64. If so, the second orifice 61 is opened. Further, at the time of reverse rotation in which friction torque acts on the relief valve 63, when the spring force of the second spring member 64 is stronger than the friction torque, the second orifice 61 is held in a closed state, and when the friction torque becomes stronger than the spring force. Force the second orifice 61
To release.

Therefore, the spring force of the second spring member 64 is set stronger than the spring force of the first spring member 25. When the rotary valve 11 rotates forward in the direction indicated by the arrow A in FIG. 1, the plate portion 26 hits the projection 17A of the cam housing 4, and the closing valve 2 is driven by friction torque.
When the spring force of the first spring member 25 is stronger than the friction torque, the closing valve 24 keeps the first orifice 22 open.

On the other hand, the friction torque is
If the spring force of the second spring member 64 is stronger than the hydraulic pressure from the collecting chamber 20 during the forward rotation that does not act on the
Keeps the second orifice 61 closed. When such forward rotation is not locked, normal torque characteristics are obtained. Next, as shown in FIG. 2, during normal rotation, when the friction torque acting on the closing valve 24 exceeds the spring force of the first spring member 25, the closing valve 24 is pressed by the plate portion 26, The first orifice 22 is closed.

On the other hand, since the spring force of the second spring member 64 is stronger than the hydraulic pressure from the collecting chamber 20, the relief valve 63 keeps the second orifice 61 closed. Thus, since the first and second orifices 22 and 61 are closed, the lock characteristics are obtained. Next, as shown in FIG. 3, when the engine is rotating forward and the torque is higher than in the case of FIG. 2,
Although the closing valve 24 keeps the first orifice 22 closed, the relief valve 63 opens the second orifice 61 because the hydraulic pressure from the collecting chamber 20 becomes stronger than the spring force of the second spring member 64. . As a result, a normal rotation relief characteristic is obtained.

Next, when the rotary valve 11 rotates in the reverse direction in the direction shown by the arrow B in FIG. 4, the friction torque does not act on the closing valve 24, and the closing valve 24 holds the first orifice 22 in the open state. I do. On the other hand, the projection 19B of the rotary valve 11 is the projection 17B of the cam housing 4.
, The friction torque acts on the relief valve 63, but when the spring force of the second spring member 64 is stronger than the friction torque, the relief valve 63 keeps the second orifice 61 closed. At the time of the reverse rotation, normal torque characteristics are obtained.

Next, as shown in FIG. 5, when the first orifice 22 is in reverse rotation, the relief valve 6 is closed.
When the friction torque acting on 3 becomes stronger than the spring force of the second spring member 64, the relief valve 63 opens the second orifice 61. This results in a forced relief characteristic. Referring again to FIG. 6, the rotary valve 11 constitutes a timing member for determining the opening / closing timing of the suction / discharge port 10, and includes notches 18A, 18B and projections 19A, 19B.
Constitutes a positioning mechanism that regulates the phase relationship between the cam 1 and the rotary valve 11.

When the plunger 8 is in the suction stroke,
There is a positional relationship between the suction port 12 of the rotary valve 11 and the suction and discharge hole 10 of the rotor 5, and the first orifice 22, the discharge oil passage 23, the suction passage 13, the suction port 12,
Through the suction and discharge holes 10 of the rotor 5, the plunger chamber 7
Oil can be inhaled. When the plunger 8 is in the discharge stroke, the relationship is opposite to that of the suction stroke, and the suction and discharge holes 10 of the rotor 5 communicate with the collecting chamber 20 through the discharge port 14 of the rotary valve 11.

Reference numeral 32 denotes a retainer that rotates integrally with the cam housing 4, and the retainer 32 supports the input shaft 6 via a bearing 33. A thrust needle bearing 35 is interposed between the retainer 32 and the rotary valve 11 through the lid member 16 and the quenching plate 34, and the friction torque on the thrust needle bearing 35 side is the friction between the rotor 5 and the rotary valve 11. It is set to be smaller than the torque. Therefore, when the direction of the differential rotation changes, the rotary valve 11 rotates together with the rotor 5 and rotates until the positioning projections 19A and 19B of the rotary valve 11 hit the projections 17A and 17B of the cam housing 4. 4 and rotate together. Thus, the suction / discharge port 10 is forcibly opened / closed at a predetermined timing even in the normal rotation or the reverse rotation.

A cover 3 is provided between the retainer 32 and the input shaft 6.
6 provided inside the cover 36 and the retainer 3
An oil seal 37 is interposed between the input shaft 6 and the input shaft 6. Oil seal 37 prevents oil from leaking out of the joint. Numerals 38 and 39 are communication paths formed in the input shaft 6, and the inside of the joint and the accumulator chamber 40 communicate with each other through the communication paths 38 and 39. Accumulator room 4
Inside 0, the accumulator piston 41 is movably housed, and the accumulator piston 41 moves according to the internal pressure of the joint. That is, the accumulator piston 41 absorbs the thermal expansion of the oil sealed in the joint.

Reference numeral 42 denotes a lid provided on the input shaft 6. The lid 42 also has a function as a stopper for the accumulator piston 41. Air 43 is sealed in the accumulator piston 41. In addition, 44 is an oiling hole, 45 is a screw hole, 46 is a needle bearing, 47 and 48 are stopper rings, and 49 and 50 are O-rings.

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 a rotation difference occurs between the cam 1 and the rotor 5, the plunger 8 in the discharge stroke is pushed in the axial direction by the cam surface 2 of the cam 1.

At this time, the suction / discharge port 10 is connected to the discharge port 1
Because of the communication with the plunger 4, the plunger 8 pushes the oil in the plunger chamber 7 from the suction / discharge port 10 to the discharge port 14 of the rotary valve 11. The oil pushed out to the discharge port 14 is supplied to the communication groove 15, the collecting chamber 20, the first orifice 2.
2, the oil is supplied from the discharge oil passage 23 to the suction passage 13.
At this time, the resistance of the first orifice 22 causes the communication groove 1
5, the hydraulic pressure in the collecting chamber 20, 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. Note that each discharge port 14 is
, The hydraulic pressures of all the plunger chambers 7 in the discharge stroke become equal.

Further, when the cam 1 rotates, a suction stroke occurs, and the suction / discharge port 10 communicates with the suction port 12.
The oil in the suction passage 13 is sucked into the plunger chamber 7 through the suction port 12 and the suction / discharge hole 10, and the plunger 8 returns along the cam surface 2 of the cam 1. When the forward rotation is not locked, as shown in FIG. 1, the spring force of the first spring member 25 is stronger than the friction torque acting on the closing valve 24, so that the closing valve 24 opens the first orifice 22. ,
On the other hand, when the spring force of the second spring member 64 is stronger than the hydraulic pressure from the collecting chamber 20, the relief valve 63 sets the second orifice 6
Close 1

Therefore, a normal torque characteristic as shown in FIG. 8C is shown. That is, when the forward rotation is not locked, the torque characteristic C is proportional to the square of the rotation speed difference ΔN. Next, when a high torque is generated on a low μ road such as a sandy ground, the friction torque acting on the rotary valve 11 increases, and when the torque exceeds the spring force of the first spring member 25, as shown in FIG. Closes the first orifice 22.

Further, since the spring force of the second spring member 64 is stronger than the hydraulic pressure from the collecting chamber 20, the relief valve 63 keeps the second orifice 61 closed. At the time of such normal rotation lock, the torque characteristic moves from the point E to the point F in FIG. Therefore,
When the vehicle is moving forward and high torque is generated on a low μ road such as a sandy ground, the first and second orifices 22 and 61 are closed,
Locking improves running performance and prevents the joint temperature from rising too high.

Next, as shown in FIG. 3, when the friction torque acting on the closing valve 24 exceeds the spring force of the first spring member 25, and the closing valve 24 closes the first orifice 22, When the oil pressure from the collecting chamber 20 becomes stronger than the spring force of the second spring member 64, the relief valve 63 opens the second orifice 61. The torque characteristic at the time of the forward rotation relief is shown in FIG.

Therefore, even if the lock mechanism operates in the event of a sudden start, the relief valve 63 opens the second orifice 61 and the torque is limited, so that a large load is not applied to the joint, and at the same time the parts are reinforced. Since it can be omitted, the cost does not increase. Next, as shown in FIG. 4, at the time of reverse rotation, the rotary valve 11 rotates in the direction shown by the arrow B, and the projection 19A separates from the projection 17A. Since the friction torque does not act on the closing valve 24, the first orifice 22 is opened. On the other hand, the projection 19B of the rotary valve 11 hits the projection 17B of the cam housing 4, and the friction torque acts on the relief valve 63. However, since the spring force of the second spring member 64 is stronger than the friction torque, the relief valve 63 is in the second position.
Orifice 61 is kept closed.

As shown in FIG. 8H, the torque characteristic at the time of the reverse rotation becomes a normal characteristic in proportion to the square of the rotational speed difference ΔN. As described above, since the locking is not performed at the time of the reverse rotation, as shown in FIG. 9, in the vehicle in which the present joint 53 is mounted on the front wheel 51 side and in the vicinity of the front wheel differential device 52, the vehicle is in the normal forward driving state. For example, it is possible to prevent the occurrence of the tight corner braking phenomenon without locking during the tight corner turning.

In FIG. 9, 54 is an engine, 55 is a transmission, 56 is a transfer, 57 is a rear wheel,
58 is a rear wheel side differential device, 59 is a rear wheel side propeller shaft, and 60 is a front wheel side propeller shaft.
Next, as shown in FIG. 5, when the closing valve 24 opens the first orifice 22 at the time of the reverse rotation, the friction torque acting on the relief valve 63 is applied to the second spring member 64.
Is exceeded, the relief valve 63 opens the second orifice 61. Thus, the forced relief is performed at the time of the reverse rotation, and the torque characteristics as shown by I in FIG. 8 are obtained. As described above, the torque can be kept low at the time of reverse rotation.
A malfunction of the BS can be prevented.

Next, FIG. 10 is an explanatory diagram of the friction torque, the hydraulic reaction force, and the spring force acting on the relief valve 63. In FIG. 10, the arrow L indicates the friction torque _Ft.
Arrow M indicates the hydraulic reaction force _Fa , and arrow N indicates the second spring member 6.
4 show the respective spring forces. The hydraulic reaction force _Fa is represented by the following formulas (1) and (3), the friction torque _Ft is represented by the formula (2), and the torque T is represented by formulas (1), (2) and (3).
Obtained from the equation. _{F a = P * S a =} k a · T ··· (1) P: high-pressure chamber Hydraulic S _a: the orifice cross-sectional area T: Torque k _a: proportionality constant _{F t = k t · T ···} (2) k _t: proportional constant _{F a = F s -F t ···} (3) (1), (2), (3) k a · T = F s -k t · T ··· (4) from the equation Next, FIG. 11 is an explanatory diagram of the friction torque, the spring force, and the hydraulic reaction force acting on the closing valve 24.

In FIG. 11, the arrow O indicates the friction torque F1 _t , the arrow P indicates the spring force of the first spring member 25,
Arrow Q in the hydraulic reaction force F1 _a, respectively. Hydraulic reaction force F
_1a is represented by the following equations (5) and (7), and the friction torque F1 _t is represented by the following equation (6): (5), (6),
Equation (8) is obtained from equation (7). (8) locking points T1 _l during full closure of the first orifice 22 is obtained from the equation.

This T1 _l is indicated by a point F in FIG. _{F1 a = k1 a · T1 ···} (5) F1 t = k1 t · T1 ··· (6) F1 a = F1 t -F1 s ··· (7) k1 a · T1 = k1 t · T1- F1 _s (8) T1 _l = F1 _s / (k1 _t -k1 _a ) (9) Next, if F1 _a = 0 in the equation (7), the following (10), Equation (11) is obtained.

[0042] (11) of the T1 _ls shows the closure start lock point of the first orifice 22, shown by point E in FIG. 8. _{F1 s = F1 t ··· (10} ) k1 t · T1 = F1 s T1 ls = F1 s / k1 t ··· (11) Next, in (3), by placing the F _t = 0, the following The relief point _Tr at the time of the normal rotation relief as shown in the equation (12) is obtained. _{k a · T = F s T} r = F s / k a ··· (12) T r is represented by point R in FIG. 8.

Next, the lock point T at the time of reverse rotation relief
_b is obtained by the following equation (13) or (14).
The lock point _Tb is indicated by a point J in FIG.

[0044]

(Equation 1)

In FIG. 8, the lock characteristic is shifted from the point E to the point F at the time of normal rotation so as to obtain the lock characteristic shown by D.
It has good running performance on sand and rough roads, and the joint temperature does not rise too much. In addition, when the vehicle suddenly starts, even if the locking characteristic shown by D is reached, the relief is performed as shown by G, so that the torque is limited. Since the reinforcement can be omitted, the cost does not increase.

Further, since the relief is forcibly performed at the time of reverse rotation to obtain the characteristic indicated by I, the torque characteristic can be suppressed low, and malfunction of the ABS can be suppressed.

[0047]

As described above, according to the present invention, locking is performed at the time of forward rotation, so that the running performance on sandy ground and rough roads is good, and the joint temperature does not rise excessively. Also, at the time of sudden start, even if the lock mechanism works, the torque is limited by relief,
A large load is not applied to the joint, and at the same time, the reinforcement of the parts can be omitted, so that the cost does not increase.

Further, at the time of reverse rotation, the forced relief works, so that the torque characteristics can be suppressed to a low level, and malfunction of the ABS can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state at the time of forward rotation unlocking showing one embodiment of the present invention.

FIG. 2 is a diagram showing a state at the time of normal rotation lock;

FIG. 3 is a diagram showing a state at the time of normal rotation relief;

FIG. 4 is a diagram showing a state at the time of reverse rotation and no relief.

FIG. 5 is a diagram showing a state at the time of reverse rotation forced relief;

FIG. 6 is a sectional view of the entire joint.

FIG. 7 is a perspective view of a spring member.

FIG. 8 is a graph showing torque characteristics.

FIG. 9 is a diagram showing an arrangement of joints.

FIG. 10 is an explanatory diagram of friction torque, hydraulic reaction force, and spring force.

FIG. 11 is another explanatory view of friction torque, hydraulic reaction force, and spring force.

[Explanation of symbols]

 1: cam 2: cam surface 3: welded portion 4: cam housing 5: rotor 6: input shaft 7: plunger chamber 8: plunger 9: return spring 10: suction / discharge hole 11: rotary valve (valve element) 12: Suction port 13: Suction path 14: Discharge port 15: Communication groove 16: Lid member 17A, 17B, 19A, 19B: Projection 18A, 18B: Notch 20: Collecting chamber 22: First orifice (flow resistance generating means) 23 : Discharge oil passage 24: Shutoff valve 25: First spring member 26: Plate portion 27: Stopper portion 28: Connecting portion 29: Curved portion 30: Pin hole 31: Pin 32: Retainer 33: Bearing 34: Hardened plate 35: Thrust Needle bearing 36: Cover 37: Oil seal 38, 39: Communication passage 40: Accumulator chamber 41: Accumulator Piston 42: lid 43: air 44: lubrication hole 45: screw hole 46: needle bearing 47, 48: stopper ring 49, 50: O-ring 51: front wheel 52: front wheel side differential device 53: joint 54: engine 55: transmission 56 : Transfer 57: rear wheel 58: rear wheel side differential device 59: rear wheel side propeller shaft 60: front wheel side propeller shaft 61: second orifice 62: discharge oil passage 63: relief valve 64: second spring member 65: plate Portion 66: Stopper portion 67: Connecting portion 68: Pin 69: Pin hole 70: Bending portion

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-87163 (JP, A) JP-A-7-54868 (JP, A) JP-A-5-65926 (JP, A) JP-A-7-57 248032 (JP, A) JP-A 5-64539 (JP, U) JP-A 6-8827 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) F16D 31/02 B60K 17 / 348

Claims (3)

(57) [Claims] 1. A cam surface which is provided between input / output shafts which are relatively rotatable, is connected to said one shaft, has a cam surface having two or more peaks on an inner surface, and has a plurality of notches on an inner periphery. Formation
Cam housing and that; reciprocal to each of the plurality of plungers chamber; together are connected to the other shaft, said rotatably housed in a cam housing, a plurality of plungers chamber rotor and formed in the axial direction A plurality of plungers that are movably housed and driven by the cam surface when the two shafts rotate relative to each other; suction that opens to one end face of the rotor that does not store the plungers and communicates with the plunger chamber. a discharge hole; together rotatably sliding contact with an end surface of said rotor, said
A pair of positioning engaging the notch of the cam housing
The has a projection of use are given pivotably positioned between the cam housing, a plurality of suction ports to the action of the suction valve and the discharge valve by the positional relationship between the suction and discharge hole, the discharge port surface A high-pressure chamber formed by communicating the formed valve element and the discharge port; and a means for generating flow resistance at an outlet from the high-pressure chamber to the low-pressure chamber in the joint; a torque corresponding to a rotational speed difference between the two shafts is provided. In the hydraulic power transmission joint for transmitting, a first orifice as the flow resistance generating means is provided on one projection of the valve body, and the other orifice on the opposite side is provided .
A second orifice is provided on the projection, and when the relative rotational direction of the input / output shaft is normal rotation, when the friction rotational force acting on the valve body due to sliding contact with the rotor exceeds a predetermined value, the first orifice is provided . orifice was closed, provided with a shut-off valve which opens during the reverse rotation, forward rotation is closed the second orifice, opening the second orifice when the pressure in the high pressure chamber exceeds a predetermined value, A relief valve for forcibly opening the second orifice when a frictional rotational force acting on the valve body due to sliding contact with the rotor exceeds a predetermined value when the relative rotation direction of the input / output shaft is reversed. A hydraulic power transmission coupling characterized by comprising: 2. A has a plate portion for pushing the shut-off valve, a normal rotation, closes the first orifice when a strong frictional rotational force than the spring force acts, said at reversing the a first spring member for urging the shut-off valve to open the first orifice has a plate portion for pushing the relief valve, the first time the spring force from the hydraulic pressure from the high pressure chamber during forward rotation is strong the second orifice is closed, the friction rotational force to a reverse rotation is characterized by comprising a second spring member for urging the relief valve to open the second orifice when stronger than the spring force claims Item 1. A hydraulic power transmission coupling according to Item 1. 3. The hydraulic power transmission coupling according to claim 2, wherein a spring force of said second spring member is made stronger than a spring force of said first spring member.