JP2000310248A - Hydraulic power transmission coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a shock from being felt, even if a peak torque is produced when starting on a low μ road, without locking at that moment. SOLUTION: This power transmission coupling comprises a lock pin member 45, which when a hydraulic pressure rises beyond a prescribed value, moves to make free a held valve disc 40, so as to close an orifice 52 as flow resistance producing means and a plug member 54 closing a storage hole 46 having the lock pin member 45 stored therein and holding a spring 55 energizing the lock pin member 45. Then, an orifice 56 is provided in the plug member 54 to communicate the oil-filled storage hole 46 with a low pressure side at the rear of the lock pin member 45 to delay the movement of the lock pin member 45.

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 which is used for distributing driving force of a vehicle, and in particular, eliminates a lock shock at the time of starting.

[0002]

2. Description of the Related Art Conventional hydraulic power transmission couplings include, for example, the following.

[0003] The hydraulic power transmission coupling is provided between an input / output shaft that is rotatable relative to each other, connected to the one shaft, and formed on a cam surface having two or more peaks on an inner surface thereof; A rotor connected to the other shaft and rotatably housed in the cam housing and having a plurality of plunger chambers formed in the axial direction; and pressing a return spring on each of the plurality of plunger chambers. A plurality of plungers which are received and reciprocally housed and are driven by the cam surface when the two shafts rotate relative to each other; a suction / discharge hole formed in the rotor and communicating with the plunger chamber; And rotatably slidably contact an end surface of the suction valve, and are positioned in a predetermined relationship with the cam housing. A rotary valve having a plurality of suction ports and a discharge port formed on the surface thereof serving as a valve outlet; and a flow resistance generating means for generating flow resistance by the flow of the discharge oil by driving the plunger; Transmits torque according to the speed difference.

In this conventional hydraulic power transmission coupling, torque is generated in the hydraulic pressure in accordance with the differential rotation of the front and rear wheels,
When the oil pressure reaches a predetermined value, the orifice that generates the flow resistance is closed and locked.

[0005] That is, as shown in FIG. 8, when the front and rear wheel differential rotation speed ΔN does not reach a predetermined value, the hydraulic pressure is small.
Since the force of pressing the lock pin member 105 by the spring 106 is greater than the force of pressing the lock pin member 105 by the hydraulic pressure in the storage chamber 104 of the collar member 103 stored in the high-pressure chamber 102 communicating with the discharge port 101 formed in the rotary valve 100. The ball 107 is held by the lock pin member 105, and the oil passes through the orifice 108. The oil that has passed through the orifice 108
It flows out to the low-pressure side from the low-pressure hole 110 opened at 9.

Therefore, the torque characteristic at this time is a normal torque characteristic as shown by A in FIG.

Next, when the front and rear wheel differential rotation speed ΔN exceeds a predetermined value, the oil pressure in the storage chamber 104 increases, and the force of pressing the lock pin member 105 by the oil pressure in the storage chamber 104 increases the lock pin member 105 by the spring 106. , The lock pin member 105 moves rightward, the spring 106 contracts, and the ball 107 becomes free,
The ball 107 is seated on the valve seat 111 and the orifice 108
Is closed. The torque characteristic at this time is a lock characteristic as shown in FIG.

The storage hole 10 behind the lock pin member 105
9 communicates with the low-pressure side, and as shown in FIG. 9, when the lock point C is reached, the lock pin member 105 moves rightward without delay, and the ball 107 becomes free.
After sitting on the valve seat 111, the orifice 108 is closed. Thus, a locked state is obtained.

[0009]

However, in such a conventional hydraulic power transmission coupling, excellent running performance can be obtained by locking on a road surface that requires a high driving force, such as sandy ground or deep snowy ground. However, on a low μ road such as an icy road or a snow-covered road, a high driving force is not required.

[0010] That is, since the road surface such as a sandy ground or a deep snowy ground is rough, a shock due to the lock at the time of starting is not felt. There was a problem of feeling to the body.

The present invention has been made in view of such conventional problems, and has as its object to provide a hydraulic power transmission coupling that does not lock when starting and does not feel a shock due to locking. .

[0012]

In order to achieve this object, the present invention is configured as follows.

The invention according to claim 1 is provided between an input / output shaft that is rotatable relative to each other, is connected to the one shaft, and has two
A cam housing formed on a cam surface having one or more peaks; a rotor connected to the other shaft and rotatably housed in the cam housing, and having a plurality of plunger chambers formed in an axial direction; A plurality of plungers housed in each of the plurality of plunger chambers so as to be reciprocally movable under the pressure of a return spring and driven by the cam surface when the two shafts rotate relative to each other; A suction / discharge port communicating with the plunger chamber; rotatably slidably contacting the end face of the rotor; being positioned in a predetermined relationship with the cam housing; And a plurality of suction ports acting as discharge valves, a rotary valve having discharge ports formed on the surface thereof, and a plunger driven by the plunger. Comprising a flow resistance generating means for generating a flow resistance by the flow of Deyu; in hydraulic power transmission joint for transmitting torque corresponding to the rotational speed difference between the two shafts,
A lock pin member for closing the orifice as the flow resistance generating means by releasing the valve body that has been moved and held when the oil pressure rises to a predetermined value or more, and a lock pin for closing a storage hole for storing the lock pin member. A plug member for holding a spring for biasing the member, and the plug member is provided with an orifice for communicating the oil-filled storage hole behind the lock pin member with the low pressure side to delay the movement of the lock pin member.

According to a second aspect of the present invention, in the hydraulic power transmission coupling according to the first aspect, instead of the orifice, an oil-filled storage hole behind the lock pin member and a low pressure side are provided at an end face of the plug member. And a slit for delaying the movement of the lock pin member.

According to a third aspect of the present invention, in the hydraulic power transmission joint according to the first aspect, instead of the orifice, an oil behind the lock pin member is provided on an outer peripheral portion of a seal member provided on the lock pin member. A slit for communicating the filled storage hole with the low pressure side and delaying the movement of the lock pin member was formed.

According to a fourth aspect of the present invention, in the hydraulic power transmission coupling according to any one of the first to third aspects, the time for delaying the movement of the lock pin member is made variable by the sectional area of the orifice or the sectional area of the slit. .

According to the present invention, the lock pin member for closing the orifice serving as the flow resistance generating means by releasing the valve body which has been moved and held when the oil pressure rises to a predetermined value or more, and the lock pin member are housed. A plug member that closes the storage hole and retains a spring that biases the lock pin member.The plug member communicates the oil-filled storage hole behind the lock pin member with the low-pressure side to move the lock pin member. Since an orifice to delay is provided, even if peak torque occurs when starting on a low μ road, it will not lock at that moment, so
There is no rock shock. In addition, when a high driving force is required, the vehicle is locked after a predetermined delay, so that traveling performance is maintained.

Further, instead of the orifice, a slit is formed in the end face of the plug member to communicate the oil-filled storage hole behind the lock pin member with the low-pressure side to delay the movement of the lock pin member. Effects can be obtained.

Instead of the orifice, a slit is provided in the outer peripheral portion of the seal member provided in the lock pin member to communicate the oil-filled storage hole behind the lock pin member with the low pressure side to delay the movement of the lock pin member. The same effect as described above can be obtained also when formed.

Further, the time for delaying the movement of the lock pin member can be made variable by the cross-sectional area of the orifice or the cross-sectional area of the slit, and the time until locking can be freely controlled.

[0021]

FIG. 1 is a sectional view showing an embodiment of the present invention.

In FIG. 1, 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. Further, the cam 1 is fixed to the cam housing 4 at the welding portion 3,
The cam 1 rotates integrally with the cam housing 4.

Reference numeral 5 denotes a rotor rotatably housed in the cam housing 4, and 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, and a plurality of plungers 8 are slidably accommodated in the plunger chamber 7 via a return spring 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 in which a discharge port 14 is formed.
Is formed with a communication groove 15 communicating with each of them. Further, a lid member 16 is provided in close contact with the back surface, and the communication groove 15 is closed.

The rotary valve 11 has a positioning projection 18 which engages with a notch 17 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 port 10, and the notch 17 and the projection 18 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 step,
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.
Oil can be sucked into the plunger chamber 7 through the suction passage 13 and the suction and discharge holes 10 of the rotor 5.

When the plunger 8 is in the discharge step, the relationship is the reverse of the suction step, and the suction and discharge holes 10 of the rotor 5 communicate with the communication groove 15 via the discharge port 14 of the rotary valve 11.

A bearing retainer 19 rotates integrally with the cam housing 4, and supports the input shaft 6 via a bearing 20. A thrust needle bearing 21 is interposed between the bearing retainer 19 and the rotary valve 11, and the friction torque on the thrust needle bearing 21 side is set to be smaller than the friction torque between the rotor 5 and the rotary valve 11. I have.

Therefore, when the direction of the differential rotation changes,
The rotary valve 11 rotates together with the rotor 5, rotates until the positioning projection 18 of the rotary valve 11 hits the notch 17 of the cam housing 4, and then rotates together with the cam housing 4. As a result, the suction / discharge port 10 is forcibly switched at a predetermined timing even at the time of forward rotation or reverse rotation.

An oil seal 22 is provided between the bearing retainer 19 and the input shaft 6, and an accumulator piston 23 for absorbing thermal expansion and contraction of oil is slidably housed inside the input shaft 6. Have been. Reference numeral 24 denotes a lid member for preventing muddy water from entering the O-ring sliding portion of the accumulator chamber 25.

The accumulator chamber 25 communicates with the inside of the joint via oil passages 26 and 27. In addition, 30 is a lubrication hole, 31 is a needle bearing, 32 is a screw hole, 33,
34 is an O-ring, 35 and 36 are snap rings, and 37 is a mounting hole.

FIG. 2 is a view showing a part of the rotary valve 11.

In FIG. 2, reference numeral 11 denotes a rotary valve, and the rotary valve 11 has a discharge port 14 formed therein. A high-pressure chamber 28 is formed in the rotary valve 11 so as to communicate with the discharge port 14 through a through hole 38. A hardened color member 39 is accommodated in the high-pressure chamber 28, and a plug 29 is connected to the collar member 39. Screwed.

A storage chamber 41 in which a ball 40 as a valve body is movably stored is formed in the collar member 39. The storage chamber 41 communicates with the communication hole 38 via the opening 42 and communicates with the communication hole 44 via the opening 43.

The communication hole 44 communicates with a storage hole 46 for storing the lock pin member 45, and the lock pin member 45 is slidably stored in the storage hole 46. Lock pin member 45
Is a small-diameter pin portion 47, a large-diameter base end portion 48, and a stopper portion 4.
The position of the ball 40 is controlled by the lock pin member 45.

A groove 50 is formed on the outer periphery of the base end portion 48,
An oil seal 51 is interposed in the groove 50. Also,
A stopper 49 projects from the base end 48, and the amount of movement of the lock pin member 45 is regulated by the stopper 49.

The gap between the pin portion 47 and the communication hole 44 is
An orifice 52 is provided as flow resistance generating means. Therefore, the diameter of the communication hole 44 can be increased.

When the ball 40 is held by the lock pin member 45, the orifice 52 is open. However, when the ball 40 is free, the ball 40 becomes a valve seat formed in the opening 43 of the collar member 39. Seated at 53,
The orifice 52 is closed.

The housing hole 46 is provided with a plug (plug member) 54.
, And a spring 55 is interposed between the plug 54 and the base end 48 of the lock pin member 45.
An orifice 56 for delaying the movement of the lock pin member 45 is formed in the plug 54, and the storage hole 46 behind the lock pin member 45 communicates with the low pressure side via the orifice 56. The storage hole 46 is filled with oil,
When the lock pin member 45 moves rightward, the oil is discharged to the low pressure side through the orifice 56.

The lock pin member 45 housed in the housing hole 46 is urged by a spring 55 to hold the ball 40, and when the oil pressure in the housing chamber 41 for housing the ball 40 rises above a predetermined value, The lock pin member 45 attempts to move rightward against the spring 55, but the storage hole 46 is filled with oil, and the movement is delayed by the orifice 56. If the high torque is maintained, the lock pin member 45 will be
The stopper 49 abuts on the plug 54 to prevent the stopper 49 from moving more than a certain distance. A low pressure hole 57 through which the oil passing through the orifice 52 is discharged is formed in the storage hole 46 of the lock pin member 45 on the orifice 52 side.

FIG. 3 is a sectional view of a main part of FIG.

In FIG. 3, a high-pressure chamber 28 communicating with the discharge port 14 is formed in the rotary valve 11, and a collar member 39 is housed in the high-pressure chamber 28. Color member 3
A storage chamber 41 for storing the ball 40 is formed in 9, and the storage chamber 41 communicates with the discharge port 14 through the through hole 38. The storage chamber 41 communicates via a communication hole 44 with a storage hole 46 in which a lock pin member 45 is movably stored. A gap between the pin portion 47 of the lock pin member 45 and the communication hole 44 forms an orifice 52 as flow resistance generating means. A spring 55 is interposed between the plug 54 for closing the storage hole 46 and the base end 48 of the lock pin member 45 having the groove 50 with the oil seal 51 interposed therebetween. Energized,
The ball 40 is held.

An orifice 56 for delaying the movement of the lock pin member 45 is formed in the plug 54, and the orifice 5
The storage hole 46 behind the lock pin member 45 communicates with the low-pressure side via 6. The storage hole 46 is filled with oil, so that even if a peak torque is generated at the time of starting on a low μ road, the lock is not performed by the action of the orifice 56 at that moment.

The moving time of the lock pin member 45 is regulated by changing the area of the orifice 56.

Assuming that the area of the base end portion 48 of the lock pin member 45 is SA, the movement stroke of the lock pin member 45 is S, the generated torque is ΔT, and the area of the orifice 56 is a, the time Δt until locking is Δt∝. There is a relationship of (SA × S) / (√ΔT × a). Therefore, when the area a of the orifice 56 is increased, the time Δt until locking becomes shorter,
When the area a of the orifice 56 is reduced, the time Δt until locking becomes longer.

Next, the operation will be described.

In FIG. 1, when there is no rotation difference between the cam 1 and the rotor 5, 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 14
Plunger 8 is in plunger room 7
Is pushed out 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 from the suction passage 13 to the suction port 12 through the orifice. At this time, the discharge port 1
4. The hydraulic pressure in the plunger chamber 7 rises, and a reaction force is generated in the plunger 8.

By rotating the cam 1 against the plunger reaction force, torque is generated, and the cam 1 and the rotor 5 are rotated.
And torque is transmitted between them. Since the discharge port 14 is communicated with the communication groove 15, the hydraulic pressure of all the plunger chambers 7 in the discharge stroke becomes 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.

2 and 3, the front and rear wheel differential rotational speed Δ
When N does not reach the predetermined value, the hydraulic pressure is low and the storage chamber 4
Since the force of pressing the lock pin member 45 by the spring 55 is greater than the force of pressing the lock pin member 45 by the hydraulic pressure, the ball 40 is held by the lock pin member 45 and the oil passes through the orifice 52. Therefore,
The torque characteristic at this time is a normal torque characteristic as shown by A in FIG.

Next, when the front and rear wheel differential rotation speed ΔN exceeds a predetermined value, the oil pressure in the storage chamber 41 increases, and the force of pressing the lock pin member 45 by the oil pressure in the storage chamber 41 increases the lock pin member 45 by the spring 56. Pressing force is larger than
Although the lock pin member 45 is about to move to the right, oil is filled in the storage hole 46 behind the lock pin member 45, and the oil passes through the orifice 56.
The movement of the lock pin member 45 is delayed.

Therefore, even if a peak torque is generated when the vehicle starts on a low μ road, the lock pin member 45 does not move rightward at that moment, so that it is not locked. As a result, no rock shock is felt.

On the other hand, when a high driving force is required (when a high torque is connected), the oil filled in the storage hole 46 behind the lock pin member 45 passes through the orifice 56 to the low pressure side. After being discharged, the lock pin member 45 moves rightward as indicated by an arrow several seconds after being delayed, so that the ball 40 is held by the lock pin member 45 and becomes free, and seats on the valve seat 53 to release the orifice 52. Close. The torque characteristic at this time is a lock characteristic as shown in FIG. Therefore, in this locked state, the traveling performance of the vehicle is maintained.

As described above, when the vehicle is started on the low μ road, the vehicle is not locked at that moment, so that no lock shock is felt. Further, when a high driving force is required, the vehicle is locked after a few seconds and the running performance is maintained. In addition, the time until locking can be regulated by changing the area of the orifice 56.

FIG. 4 is a sectional view showing a main part of a second embodiment of the present invention.

In FIG. 4, the orifice 5 shown in FIGS.
A slit 58 was formed in the end face of the plug 54 instead of 6. As shown in FIG. 5, the slit 58 is formed on the end face of the plug 54. The slit 58 is provided to delay the movement of the lock pin member 45, and communicates with the low pressure side via the through hole 59. That is, the storage hole 46 behind the lock pin member 45 communicates with the low pressure side via the slit 58 and the through hole 59. The oil is filled in the storage hole 46 behind the lock pin member 45, and even if a peak torque is generated at the time of starting on a low μ road, the lock pin member 45 does not move at that moment. do not do.

Assuming that the area of the slit 58 is b, the time Δt until locking has a relationship of Δt∝ (SA × S) / (√ΔT × b). It is possible to regulate the time Δt until the operation. When a high driving force is required (when a high torque is connected), the vehicle locks after a few seconds and the running performance is maintained.

The other structure is the same as that of FIG.

FIG. 6 is a sectional view showing a main part of a third embodiment of the present invention.

In FIG. 6, the orifice 5 shown in FIGS.
A slit 60 was formed in the outer peripheral portion of the oil seal 51 instead of 6.

The groove 50 in the base end 48 of the lock pin member 45
7 is provided with a cylindrical oil seal (seal member) 51 as shown in FIG.
A slit 60 is formed in the axial direction. The slit 60 is
The storage hole 46 is provided to delay the movement of the lock pin member 45, and the storage hole 46 behind the lock pin member 45 and the storage hole 46 on the orifice 52 side of the lock pin member 45.
Communicate with each other through a slit 60.

The oil is filled in the storage hole 46 behind the lock pin member 45, and when the lock pin member 45 moves rightward as indicated by the arrow, the oil is supplied to the slit 60, the inner wall of the storage hole 46 and the base end. The gas enters the storage hole 46 on the orifice 52 side through the gap with the portion 48, and is discharged from the low pressure hole 57 to the low pressure side.

Even if a peak torque is generated at the time of starting on a low μ road, the lock pin member 45 does not move at that moment due to the slit 60 for delaying the movement of the lock pin member 45, so that the lock is not locked. Assuming that the area of the slit 60 is c, the time Δt until locking has a relationship of Δt∝ (SA × S) / (√ΔT × c). By changing the area c of the slit,
The time Δt until locking can be restricted. When a high driving force is required (when a high torque is connected), the vehicle locks after a few seconds and the running performance is maintained.

The other configuration is the same as that of FIG.

[0070]

As described above, according to the present invention, when the hydraulic pressure rises to a predetermined value or more, the lock pin that moves and holds the valve body free to close the orifice as flow resistance generating means. A member and a plug member that holds a spring that closes a storage hole that stores the lock pin member and urges the lock pin member, and the plug member has an oil-filled storage hole behind the lock pin member and a low pressure side. And an orifice for delaying the movement of the lock pin member is provided, so that even if a peak torque is generated at the time of starting on a low μ road, the peak is not locked at that moment, so that no lock shock is felt. Further, when a high driving force is required, the vehicle is locked after a predetermined delay, so that the traveling performance is maintained.

Also, in place of the orifice, a slit is formed in the end face of the plug member to communicate the oil-filled storage hole behind the lock pin member with the low pressure side to delay the movement of the lock pin member as described above. Effects can be obtained.

Instead of the orifice, a slit is provided in the outer peripheral portion of the seal member provided on the lock pin member to communicate the oil-filled storage hole behind the lock pin member with the low pressure side to delay the movement of the lock pin member. The same effect as described above can be obtained also when formed.

Further, the time for delaying the movement of the lock pin member can be made variable by the cross-sectional area of the orifice or the cross-sectional area of the slit, and the time until locking can be freely controlled.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a partial sectional view of a rotary valve.

FIG. 3 is a sectional view of a main part of FIG. 2;

FIG. 4 is a sectional view of a main part showing a second embodiment of the present invention.

FIG. 5 is a partial perspective view of a plug.

FIG. 6 is a sectional view of a main part showing a third embodiment of the present invention.

FIG. 7 is a partial perspective view of a seal member.

FIG. 8 shows a conventional example.

FIG. 9 is a diagram showing torque characteristics.

[Explanation of symbols]

 1: cam 2: cam surface 3: welding portion 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 17: Notch 18: Projection 19: Bearing retainer 20: Bearing 21: Thrust needle bearing 22: Oil seal 23: Accumulator piston 24: Lid member 25: Accumulator chamber 26 , 27: oil passage 28: high pressure chamber 29: plug 30: lubrication hole 31: needle bearing 32: screw hole 33, 34: O-ring 35, 36: snap ring 37: mounting hole 38: through hole 39: collar member 40: Ball 41: Storage chamber 42, 43: Opening 44: Communication hole 45: Lock Pin member 46: Storage hole 47: Pin portion 48: Base end portion 49: Stopper portion 50: Groove 51: Oil seal (seal member) 52: Orifice (flow resistance generating means) 53: Valve seat 54: Plug (plug member) 55: Spring 56: Orifice 57: Low pressure hole 58, 60: Slit 59: Through hole

Continuing from the front page (72) Inventor Tadahiko Kato 2418 Washizu, Kosai-shi, Shizuoka Prefecture, Fuji Inside Univ. 2418 Washizu, Kosai Prefecture, Japan Inside Fuji Univance Co., Ltd. (72) Inventor Makoto Sato 2418 Washizu, Kosai City, Shizuoka Prefecture Inside Fuji Univance Co., Ltd. 72) Inventor Shunji Takasaki 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Inside Nissan Motor Co., Ltd. (72) Inventor Hirotaka Kuskawa 2 Takaracho, Kanagawa-ku, Yokohama City, Kanagawa Prefecture Nissan Motor Co., Ltd. 2F Takaracho, Kanagawa-ku, Yokohama-shi Nissan Motor Co., Ltd. F term (reference) 3D043 AA08 AB17 EA01 EA11 EB06 EB13 EE07 EF06 EF17

Claims (4)

[Claims] A cam housing provided between input and output shafts which are rotatable relative to each other and connected to said one shaft and formed on a cam surface having two or more peaks on an inner surface; and connected to said other shaft. And a rotor rotatably housed in the cam housing and having a plurality of plunger chambers formed in the axial direction; each of the plurality of plunger chambers being reciprocally movable by being pressed by a return spring. A plurality of plungers housed and driven by the cam surface when the two shafts rotate relative to each other; a suction / discharge hole formed in the rotor and communicating with the plunger chamber; and a rotatable end face of the rotor. A plurality of suction valves which are in sliding contact with each other and are positioned in a predetermined relationship with the cam housing, and act as suction and discharge valves depending on the positional relationship with the suction and discharge holes. A rotary valve having a port and a discharge port formed on the surface thereof; and a flow resistance generating means for generating a flow resistance by the flow of the discharge oil by driving the plunger; A hydraulic power transmission coupling, wherein when the hydraulic pressure rises to a predetermined value or more, a lock pin member for moving and holding a valve body to be free to close an orifice as the flow resistance generating means, and accommodating the lock pin member A plug member that closes the storage hole and holds a spring that biases the lock pin member. The plug member is connected to an oil-filled storage hole behind the lock pin member and the low pressure side to move the lock pin member. A hydraulic power transmission coupling characterized by providing an orifice for delaying the power transmission. 2. The hydraulic power transmission coupling according to claim 1, wherein, instead of the orifice, an oil-filled storage hole behind the lock pin member communicates with an end face of the plug member and a low-pressure side. A hydraulic power transmission coupling, wherein a slit for delaying the movement of the pin member is formed. 3. The hydraulic power transmission coupling according to claim 1, wherein an oil-filled storage hole behind the lock pin member is provided on an outer peripheral portion of a seal member provided on the lock pin member instead of the orifice. A hydraulic power transmission coupling characterized by forming a slit communicating with the low pressure side and delaying the movement of the lock pin member. 4. The hydraulic power transmission coupling according to claim 1, wherein a time for delaying the movement of the lock pin member is made variable by a sectional area of the orifice or a sectional area of the slit. Hydraulic power transmission coupling.