JPS6225541Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic clutch control valve device for controlling the oil pressure of a hydraulic clutch, and in particular,
This invention relates to a hydraulic clutch control valve device that reduces the shock generated when the clutch is engaged and allows the vehicle to smoothly reach steady vehicle speed during high-speed rotation.

[Prior Art] When performing a gear shift operation using a transmission device using a hydraulic clutch, if the clutch is engaged instantaneously, a shock is generated due to the difference in reduction ratio before and after the gear shift. In order to avoid this impact, the clutch plate may be allowed to slip for a certain period of time while torque is transmitted so that the driven shaft rotational speed gradually approaches the driving shaft rotational speed, and then the clutch plate is completely connected. The most ideal way to completely connect the clutch plate after slipping is to use a device that gradually increases the oil pressure of the piston that pushes the clutch plate. Conventionally, a hydraulic clutch control valve device has been used as a device for obtaining the same. Further, in a normal pressure control valve, the pressure increases as the oil flow rate increases, and the pressure decreases as the oil flow rate decreases.

However, in conventional hydraulic clutch control valve devices, if the clutch operating hydraulic pressure characteristics at high speed rotation are adjusted to an appropriate value, the oil pressure P ₁ becomes low at low speed rotation, and the movement of the clutch piston is mostly reduced even though the flow rate is small. Since the amount of oil escapes through the relief valve, a time lag occurs and the clutch operating pressure curve becomes too gradual, resulting in an excessively long time to reach steady vehicle speed. In addition, if the clutch operating hydraulic pressure characteristics at low speed rotation are adjusted to an appropriate value, the oil pressure P ₁ will be higher at high speed rotation,
The clutch piston moves rapidly, causing shock, and the clutch hydraulic pressure curve becomes too steep, resulting in too short a time to reach steady vehicle speed, causing shock. Therefore, it was not possible to satisfy the requirements of the hydraulic pump during low-speed rotation and high-speed rotation.

In addition, a differential pressure valve has a spring disposed between the valve spool and the piston, and the ratio of the balance force can be set appropriately by using fluid pressure from a pump that acts on the valve spool and the valve spool. A transmission hydraulic pressure control device having the following is known as Japanese Patent Publication No. 46-33049.

However, with this method, it is not possible to make the rate of increase in the pressure of the clutch operating oil pressure rise in a continuous smooth curve from the middle of the oil pressure rising process, and for this reason,
It was not possible to eliminate the impact during gear shifting, and it was not possible for the clutch operating oil pressure to increase the pressure more slowly during high-speed rotation of the hydraulic pump than during low-speed rotation.

Furthermore, a modulating valve has a spring disposed between the pressure regulating valve and the piston, and the ratio of the balance force can be set appropriately by using the fluid pressure from the pump that acts on the pressure regulating valve and the spring. is known as Special Publication No. 49-32483.

However, this method discontinuously changes the rate of change of oil pressure with respect to time to engage the clutch smoothly and quickly, and the pressure rise of the clutch operating oil pressure is started from the middle of the oil pressure rising process. cannot be made into a continuous, smooth curve, and the clutch operating hydraulic pressure can increase the pressure more slowly during high-speed rotation of the hydraulic pump than during low-speed rotation. Nakatsuta.

[Problems to be solved by the invention] The purpose of the invention is to solve the above-mentioned drawbacks, and to increase the rate of increase of the clutch hydraulic pressure continuously from the middle of the hydraulic pressure rising process, thereby smoothly increasing the pressure in a curved manner. This makes it possible to suppress fluctuations in the clutch operating oil pressure due to increases and decreases in the pump oil amount and temperature changes, and also allows the clutch to be fully engaged for a longer period of time when the hydraulic pump is rotating at high speeds than at low speeds, thereby reducing clutch operation. The pressure rise curve of the hydraulic pump at high speed rotation can be made more gradual than the pressure rise curve at low speed rotation of the hydraulic pump, resulting in satisfactory clutch operation time and impact at both low speed and high speed rotation. It is an object of the present invention to provide a valve device for controlling a hydraulic clutch that can obtain a preventive action.

[Means for Solving the Problems] The hydraulic clutch control valve device of the present invention is a relief valve for adjusting clutch oil pressure, which has a relief piston in a switching valve that selectively introduces hydraulic oil from a hydraulic pump to a hydraulic clutch. In the hydraulic clutch control valve device, the relief valve is provided with a trimming plug for adjusting a set relief pressure coaxially with the relief piston, wherein the relief piston and the trimming plug have respective operating timings. A plurality of different relief valve control springs are disposed, the trimming plug is supported by a return spring, a pump oil passage is connected to the hydraulic chamber of the relief piston via an orifice formed in the relief piston, and the trimming plug is supported by a return spring. A pump oil passage is connected through an orifice that introduces hydraulic oil into the hydraulic chamber, and a back pressure P ₁ that acts on the hydraulic chamber of the relief piston and a low back pressure P _L that acts on the back side of the relief piston excluding the hydraulic chamber. , pressure receiving area A ₁ of the hydraulic chamber of the relief piston, pressure receiving area A ₂ of the rear surface of the relief piston excluding the hydraulic chamber, amount of deflection δ that is the sum of the initial deflections of the relief valve control spring, displacement distance X of the trimming plug, The travel amount Y and the constant K determined by the spring constant of the relief valve control spring are set such that the clutch operating oil pressure increases the pressure more slowly when the hydraulic pump rotates at high speed than when the hydraulic pump rotates at low speed. ₁ = {K(δ+X+Y) _−PL ·A ₂ }/A ₁ The configuration is characterized in that it is set as follows.

[Function] Hydraulic oil from the hydraulic pump is introduced into the hydraulic clutch through an orifice formed in the relief piston from the pump oil passage into the hydraulic chamber of the relief piston, which has a relief valve for adjusting the clutch oil pressure attached to the switching valve. Back pressure P ₁ acting on
A low back pressure P _L acting on the back surface of the relief piston excluding the hydraulic chamber, a pressure receiving area A ₁ of the relief piston hydraulic chamber, a pressure receiving area A ₂ of the relief piston back surface excluding the hydraulic chamber, and the relief piston and the relief piston. Deflection amount δ, which is the sum of the initial deflections of multiple relief valve control springs with different activation times, which are installed between the coaxially arranged trimming plug that adjusts the set relief pressure, and the hydraulic oil from the pump oil path is applied to the orifice. is introduced into the hydraulic chamber of the trimming plug via The clutch operating hydraulic pressure _is set so that P ₁ = {K ( _{δ +} The rate of increase is increased continuously from the middle of the oil pressure rising process, and the pressure rises smoothly in a curved manner, and due to the clutch operating oil pressure characteristics, the clutch piston moves more when the hydraulic pump is rotating at high speed than when it is rotating at low speed, The hydraulic pressure that starts the clutch engagement is lowered, and the hydraulic pressure curve increases more gradually.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 shows a hydraulic system diagram of a valve device for operating a hydraulic clutch incorporating a valve device for controlling a hydraulic clutch according to an embodiment of the present invention.

1 is a forward/reverse switching valve, 2 is a relief valve,
3 is a hydraulic pump, 4 is an oil tank, 5 is a check valve for generating lubrication oil pressure, 6 is an inching valve, 7
is a quick return valve, 8 is a forward clutch,
9 is a reverse clutch.

The valves 1, 2, 6, and 7, the hydraulic pump 3, and the oil tank 4 are connected to each other by oil passages _P1 to _P5 , as shown in FIG. A clutch lubricating oil path 10, a forward clutch oil path 8', and a reverse clutch oil path 9' are connected via a low pressure port L, a forward port F, and a reverse port R, respectively.

Furthermore, FIG. 1 shows a case where the spool of the forward/reverse switching valve 1 has been shifted from the neutral position to the left to the reverse position, and no inching operation has been performed, and the hydraulic pump 3 is driven by an engine (not shown). Oil passage P ₄ from the rear clutch oil passage 9'
The drain oil passage _P5 is disconnected from the reverse clutch oil passage 9', and the other drain oil passage _P3 is communicated with the forward clutch oil passage 8', so that the reverse clutch 9 is connected. , drain oil path P ₃ ,
P ₅ is connected directly to oil tank 4.

Oil path branched from oil path P ₄ from hydraulic pump 3
P ₂ passes through the relief valve 2 and the inching valve 6 and is shut off at the land of the spool of the forward/reverse switching valve 1, and the low pressure oil passage P ₁ that communicates the annular groove 27 of the relief valve 2 with the low pressure port L is supplied with lubricating oil pressure. Low oil pressure is being generated by the generation check valve 5.

Next, in the hydraulic clutch control valve device according to the present invention, as shown in FIG.
Relief valve 2 for clutch oil pressure adjustment with
The relief valve 2 is provided with a trimming plug 30 coaxially with the relief piston 22 for adjusting the set relief pressure.

In the relief valve 2, compression springs 28 and 29, which serve as a plurality of relief valve control springs each operating at different times, are arranged coaxially and in series between the relief piston 22 and the trimming plug 30, and the trimming plug 30 is returned to its original position. The relief piston 22 and the trimming plug 30 are supported by a spring 31 and are slidably supported around the seat 23 and inside the bottomed cylindrical case 11, respectively, with compression springs 29 and 28 in between.

The seat 23 and the bottomed cylindrical case 11 are fitted into and fixed to both ends of the hole 52 of the housing 15 while facing each other, and there is a space between the inner wall of the relief piston 22 and the end wall of the seat 23. A hydraulic chamber 25 is formed between the end wall of the trimming plug 30 and the inner wall of the bottomed cylindrical case 11, and a hydraulic chamber 32 is formed in the hydraulic chamber 25 of the relief piston 22. The pump oil passage 17 is connected to the hydraulic chamber 32 of the trimming plug 30 through the orifice 24 .
A pump oil passage 17 is connected to the pump oil passage 17 via an orifice 45 formed in the bottomed cylindrical case 11 through which hydraulic oil is introduced.

A back pressure P ₁ acting on the hydraulic chamber 25 of the relief piston 22, a low back pressure P _L acting on the back surface of the relief piston 22 excluding the hydraulic chamber 25, and a pressure receiving area of the hydraulic chamber 25 of the relief piston 22.
A ₁ , pressure-receiving area A ₂ of the back surface of the relief piston 22 excluding the hydraulic chamber 25 , the amount of deflection δ that is the sum of the initial deflections of the compression springs 28 and 29 , the trimming plug 30
The constant K determined by the displacement distance It is set so that P ₁ ={K(δ+X+Y) _−PL ·A ₂ }/A ₁ so that the pressure is increased more slowly.

The spool 16 of the forward/reverse switching valve 1 is fitted into a hole 34 of the housing 15 so as to be slidable in the longitudinal direction, and an operating lever (not shown) is connected to an end 35 of the spool 16 protruding from the hole 34. be done.

The spool 16 includes four land portions 36, 37, 38, 39 and three small diameter portions 40, 41, 42 in order from the end 35 side, and a detent ball 43 is fitted to the opposite end. Three matching annular grooves F, N, and R are provided in this order. The detent ball 43 is always urged toward the annular grooves F, N, and R sides of the spool 16 by a spring 44.

Annular stepped portions 53a and 53b are formed on the inner circumferential surface of the hole 52 of the housing 15 into which the seat 23 of the relief valve 2 and the bottomed cylindrical case 11 are fitted, and the trimming plug 30 is biased to the annular stepped portion 53a. One end of the return spring 31 is locked, and the annular stepped portion 5
The open end of the bottomed cylindrical case 11 is in contact with 3b. Further, a rod-shaped spring guide 12 extending toward the relief piston 22 is integrally provided in the center of the trimming plug 30, and the tip thereof enters into the hole 13 of the relief piston 22.

The compression springs 29 and 28 are connected to the trimming plug 30
The spring constant of the compression spring 29 is arranged in series between the relief piston 22 and the trimming plug 30 via a spring receiving stopper 33 that is movably fitted loosely into the rod-shaped spring guide 12 of the compression spring 29 . It is set significantly larger than the constant.

The connection relationship between the forward/reverse switching valve 1 and the relief valve 2 is as follows.

The relief piston 22 of the relief valve 2 is
A small diameter portion 14 is provided on its outer circumferential surface via a step, and an orifice 24 is provided on the side thereof to connect a hydraulic chamber 25 and an annular groove 26 communicating with the pump oil passage 17 .

Further, the bottomed cylindrical case 11 is provided with an orifice 45 for restricting introduction of pump oil pressure from the pump oil passage 17 into the oil pressure chamber 32 .

An annular groove 2 is provided inside the housing 15.
7 and the low-pressure oil passage 20, and oil passages 46 and 5 that connect the annular groove 26 and the pump oil passage 17.
0. An oil passage 49 (only a portion is shown) that connects the chamber housing the return spring 31 to the oil tank 4; an orifice 45 provided in the bottomed cylindrical case 11 is connected to the pump oil passage 17;
Oil passages 47, 51 are provided which are connected to. Furthermore, the housing 15 has three ports 19, 1
Port 19 is connected to forward clutch oil passage 8', port 18 is connected to reverse clutch oil passage 9', and port 21 is connected to a low pressure oil passage communicating with oil tank 4. ing.

These oil passages 20, 46, 47, 48, 49,
50, 51 and ports 18, 19, 21,
Each of them has a hole 34 opened in the middle or at one end thereof, and the opening position of each of them is set as follows with respect to the spool 16 in the neutral position.

That is, the downstream part of the oil passage 46 and the upstream part of the oil passage 48 are communicated through the gap between the small diameter part 42 of the spool 16, and the oil passage 49 and the port 19 open into the gap around the small diameter part 41 of the spool 16. are connected to each other.

Further, the oil passage 47 is connected to the port 19 and the port 18.
However, the upstream and downstream parts of the oil passages 47 and 51 are communicated with each other by an annular groove in the hole 34, and the port 18 and the port 21 are closed by the small diameter part 40. They open in the gaps and communicate with each other. The annular groove 27 of the relief valve 2 is connected to the low pressure oil passage 2 by the oil passage 48.
A check valve 5 for generating lubricating oil pressure is provided in the low pressure oil passage 20, and the necessary low pressure is generated in the low pressure oil passage 20 by the check valve 5 for generating lubricating oil pressure.

Next, the operation of the hydraulic clutch control valve device constructed as described above will be explained.

When the forward/reverse switching valve 1 shown in FIG.
6. The oil flows through the gap in the small diameter portion 42 of the spool 16 to the low pressure oil passage 20, passes through the check valve 5 for generating lubrication oil pressure, and flows from the clutch lubrication oil passage 10 to the oil tank 4 to lubricate the clutch. And spool 1
6, the hydraulic oil from the pump oil passage 17 is not supplied to the ports 19, 18, and 21, and the trimming plug 30 is kept stationary by the force of the compression springs 28, 29 and the return spring 31. It is in the same state.

Now push the spool 16 into the first connection position,
As shown in FIG. 3, when the detent ball 43 is fitted into the annular groove R of the spool 16, the spool 16
The land portion 38 of the spool 16 blocks the flow of hydraulic oil from the oil passage 46 to the low pressure oil passage 20, and the land portion 36 of the spool 16 blocks the connection between the port 18 and the port 21. At the same time, the land portion 37 of the spool 16 Move to connect oil passage 47 and port 18.

On the other hand, the upstream and downstream parts of the oil passages 46 and 50 are always in communication through an annular groove provided in the inner peripheral surface of the hole 34 of the housing 15. Therefore, the hydraulic oil from the pump oil passage 17 begins to flow into the hydraulic chamber of the reverse clutch 9 via the oil passage 47 and the port 18, and the oil pressure flowing into the reverse clutch 9 from the port 18 is transferred from the pump oil passage 17 to the relief piston. The hydraulic pressure that becomes the back pressure enters the hydraulic chamber 25 through the orifice 24 of 22.
The amount determined by the balance between the combined force of P ₁ and the low back pressure P _L , which is a low hydraulic pressure, acting on the back surface of the relief piston 22 excluding the seat 23 and the force of the compression springs 28 and 29. , the relief piston 22 moves by the same amount, and a portion of the hydraulic oil from the pump oil passage 17 escapes to the low pressure oil passage 20 through the oil passages 46 , 50 , and 48 .

Then, as shown in section A-B in Fig. 4, the gap in the hydraulic chamber of the clutch is filled with hydraulic oil for a short period of time _t1 , and then the pressure is rapidly increased to oil pressure _P1 , and the pressure is increased to C.
Start connecting the clutch at the point. At this time, the hydraulic oil in the oil passage 46 is introduced into the oil pressure chamber 25 via the oil passage 50 and the orifice 24, and the oil pressure introduced into the oil pressure chamber 25 moves the relief piston 22 in the direction of the trimming plug 30, causing the annular groove to move. 27 to oil line 50
A part of the pump pressure oil is discharged through the annular groove 27 and the oil passage 48 to the low-pressure oil passage 20 for lubrication.

On the other hand, in parallel with this operation, the pump oil pressure from the pump oil passage 17 passes through the oil passages 47, 51 and the orifice 45 provided in the bottomed cylindrical case 11 to the oil pressure chamber 3.
2, the trimming plug 30 is moved in the direction of the relief piston 22 against the repulsive force of the return spring 31 and the compression springs 28 and 29. Then, by moving the trimming plug 30, the compression spring 2
8 and 29 push back the relief piston 22 and try to close the annular groove 27 of the relief piston 22 and the oil passage 50 which are wide open. In this way, by moving the trimming plug 30, the relief valve 2
The relief setting pressure is gradually increased, and accordingly, the hydraulic pressure introduced into the hydraulic chamber of the hydraulic clutch is also gradually increased.

In this way, when the trimming plug 30 starts to move due to the hydraulic pressure in the hydraulic chamber 32, the compression springs 28 and 29 are compressed until the spring receiver stopper 33 comes into contact with the relief piston 22 along the rod-shaped spring guide 12 of the trimming plug 30. . At this time, since the spring constant of the compression spring 29 is larger than the spring constant of the compression spring 28, the compression spring 2
8 is deformed, and the compression spring 29 is hardly deformed. The hydraulic pressure in the hydraulic chamber 25 rises gradually in response to changes in the relief setting pressure determined by the compression springs 28 and 29.

In the above operation, until the oil pressure reaches P ₂ shown at point D in Figure 4, only one compression spring 28 out of the two compression springs 28 and 29 is deformed as described above, so the oil pressure is compared. The target will rise slowly.

When the oil pressure exceeds P ₂ shown at point D in FIG. 4, the trimming plug 30, which has already moved the distance b shown in FIG. 2 via the compression spring 28, comes into contact with the spring receiver stopper 33. In order to start compressing the compression spring 29 anew, the two compression springs 28, 2
9 comes to determine the relief setting pressure of the relief valve 2.

The conditions for achieving the pressure increase between C and E in Figure 4 are A/(B-A)>K ₂ K ₃ /K ₁ (K _{2 +} K ₃ ), where K ₁ is the spring constant of the return spring 31, K ₂ and K ₃ are the spring constants of the compression springs 28 and 29, A is the hydraulic effective cross-sectional area of the relief piston 22, and B is is the hydraulically effective cross-sectional area of the trimming plug 30.

When the oil pressure exceeds _P2 shown at point D in FIG. 4, A/(B-A)< _K3 / _K1 .

In this way, the rate of pressure rise is continuously increased, and a smooth pressure rise curve is obtained.

In the annular groove 27 of the relief valve 2, a low back pressure P _L resulting in low oil pressure is generated by the check valve 5 for generating lubricating oil pressure, and the cross-sectional area of the oil pressure chamber 25 of the relief piston 22 into which the seat 23 fits is A back pressure P ₁ acts on the pressure receiving area A 1 from the pump oil passage 17 via the orifice 24 , and the relief piston ₂ of the seat 23 is applied from the outer diameter of the relief piston 22 to the pressure receiving area A 1 .
A low back pressure P _L from the low pressure oil passage 20 acts on the pressure receiving area A ₂ which is the cross-sectional area of the portion excluding the outer diameter of the fitting portion with the low pressure oil passage 20 .

Therefore, the resultant force F acting on the relief _piston 22 is given by: F = _P1 · _A1 + _PLA2 .

Since this resultant force F is balanced with the biasing force of the compression springs 28 and 29, the following equation is obtained: K(δ+X+Y)=F=P ₁ ·A ₁ +P _L ·A ₂ (1).

Here, δ is the amount of deflection that is the sum of the initial deflections of the compression springs 28 and 29, X is the displacement distance of the trimming plug 30, and Y is the amount of movement of the relief piston 22.

And K is a constant determined by the spring constant of the compression springs 28 and 29, K=k ₁ · k ₂ / (k ₁ + k ₂ ), where k ₁ and k ₂ are the spring constants of the compression springs 28 and 29, respectively. is the spring constant.

Therefore, from equation (1), P ₁ = { _{K ( δ +}
P ₁ becomes low _{, and} when _the low back pressure _P Since the amount of movement Y of the piston 22 changes,
It becomes possible to maintain almost constant pressure. Therefore, when the rotation speed and oil temperature of the hydraulic pump 3 change and the flow rate increases, the low back pressure P _L increases, and when the flow rate decreases, the low back pressure P _L decreases, so that the low speed of the hydraulic pump 3 increases. During high-speed rotation, the clutch piston moves and the hydraulic pressure _P1 that starts the clutch connection is made slightly lower during high-speed rotation than during rotation. Therefore, the fourth
As shown in the figure, when the clutch moves to connect, even if the discharge amount of the hydraulic pump 3 is small at low speed, the entire amount is applied to the piston, so the piston moves quickly compared to the flow rate, and at high speed rotation. Even if the discharge amount of the hydraulic pump 3 is large, most of it blows away from the relief valve 2, so the piston does not move suddenly even if the flow rate increases, and the rotation speed changes during the movement time _t1 of the clutch piston. becomes almost constant, the shock is relaxed, and according to the formula Q = B (dx / dt) = BV = K√, the hydraulic pressure P ₁ is lower at high speed rotation than at low speed rotation, so Δp is reduced. As a result, the moving speed of the trimming plug 30 can be further reduced, and the clutch operating hydraulic pressure characteristic will have a gentler upward curve. When starting the vehicle, the driven side begins to rotate as the rotational speed increases, and it is better to appropriately lengthen the time it takes to accelerate as the torque increases and complete the connection, thereby reaching the steady vehicle speed more smoothly.

[Effects of the invention] As described above, according to the hydraulic clutch control valve device of the present invention, the clutch hydraulic pressure can be adjusted by having a relief piston in the switching valve that selectively introduces hydraulic oil from the hydraulic pump to the hydraulic clutch. relief valves are arranged in parallel, and a trimming plug for adjusting a set relief pressure is disposed on the relief valve coaxially with the relief piston, and a plurality of trimming plugs each having different operation timings are disposed between the relief piston and the trimming plug. A relief valve control spring is disposed, the trimming plug is supported by a return spring, a pump oil passage is connected to the hydraulic chamber of the relief piston via an orifice formed in the relief piston, and the hydraulic chamber of the trimming plug is connected to the hydraulic chamber of the trimming plug. A back pressure P1 acting on the hydraulic chamber of the relief piston, a low back pressure P _L acting on the back side of the relief piston excluding the hydraulic chamber, and _a relief Pressure receiving area of piston hydraulic chamber
A ₁ , pressure receiving area excluding the hydraulic chamber of the relief piston
A ₂ , the amount of deflection δ that is the sum of the initial deflections of the relief valve control spring, the displacement distance of the trimming plug X,
A constant K determined by the travel amount Y of the relief piston and the spring constant of the relief valve control spring is determined so that the clutch operating oil pressure increases more slowly when the hydraulic pump rotates at high speed than when the hydraulic pump rotates at low speed. By setting P ₁ = {K (δ + X + Y) - P _L · A ₂ } / A ₁ so that the clutch hydraulic pressure increases, the rate of increase is continuously increased from the middle of the oil pressure increase process of the clutch operating oil pressure, and a curved shape is created. It is possible to increase the pressure smoothly, suppress fluctuations in the clutch operating oil pressure due to increases and decreases in pump oil amount and temperature changes, and also reduce the time it takes for the clutch to fully engage when the hydraulic pump is rotating at high speeds rather than when it is rotating at low speeds. By increasing the length of the clutch hydraulic pressure, the pressure rise curve at high speed rotation of the hydraulic pump can be made more gradual than the pressure rise curve at low speed rotation, and the pressure is satisfied at both low speed rotation and high speed rotation. It is possible to obtain a long clutch operation time and anti-shock operation.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic system diagram of a valve device equipped with a hydraulic clutch control valve device according to the present invention;
FIG. 2 is a longitudinal cross-sectional view of the main parts of the hydraulic clutch control valve device according to the embodiment of the present invention in the neutral state, and FIG. 3 is a longitudinal cross-sectional view of the main parts in the same connected state.
FIG. 4 is a hydraulic characteristic diagram same as above. 1... Forward/forward switching valve, 2... Relief valve, 3... Hydraulic pump, 4... Oil tank, 5...
Check valve for generating lubrication oil pressure, 6... Inching valve, 7... Quick return valve, 8...
...Forward clutch, 8'...Forward clutch oil path, 9
...Reverse clutch, 9'...Reverse clutch oil path,
10... Clutch lubricating oil path, 11... Bottomed cylindrical case, 12... Rod-shaped spring guide, 13... Hole, 1
4... Small diameter part, 15... Housing, 16... Spool, 17... Pump oil path, 18, 19, 21
... Port, 20 ... Low pressure oil passage, 22 ... Relief piston, 23 ... Seat, 24 ... Orifice, 25 ... Hydraulic chamber, 26, 27 ... Annular groove, 2
8, 29... Compression spring, 30... Trimming plug, 31... Return spring, 32... Hydraulic chamber, 33...
... Spring receiving stopper, 34 ... Hole, 35 ... End, 36, 37, 38, 39 ... Land part, 4
0, 41, 42...small diameter section, 43...detent ball, 44...spring, 45...orifice, 4
6, 47, 48, 49, 50, 51... oil road, 5
2... Hole, 53a, 53b... Annular step, F,
N, R...Annular groove, _P1 ...Low pressure oil path, _P2 ...Oil path, _P3 , _P5 ...Drain oil path, _P4 ...Oil path from the hydraulic pump.

Claims (1)

[Utility Model Claims] In a hydraulic clutch control valve device in which a relief valve having a relief piston for adjusting clutch oil pressure is provided in addition to a switching valve which introduces hydraulic oil from a hydraulic pump to a hydraulic clutch in a freely switchable manner, and a trimming plug for adjusting a set relief pressure is provided coaxially with the relief piston in the relief valve, a plurality of relief valve control springs each having a different operation timing are provided between the relief piston and the trimming plug, the trimming plug is supported by a return spring, a pump oil passage is connected to the hydraulic chamber of the relief piston via an orifice formed in the relief piston, and a pump oil passage is connected to the hydraulic chamber of the trimming plug via an orifice which introduces hydraulic oil, and a back pressure _P1 acting on the hydraulic chamber of the relief piston, a low back pressure _PL acting on the back surface of the relief piston excluding the hydraulic chamber, a pressure-receiving area _A1 of the hydraulic chamber of the relief piston, and a pressure-receiving area _A2 of the back surface of the relief piston excluding the hydraulic chamber a constant K determined by the total deflection δ of the relief valve control spring, the displacement distance X of the trimming plug, the movement amount Y of the relief piston, and the spring constant of the relief valve control spring, is set so as to satisfy _P1 = {K(δ + X + Y) - _PLA2 }/ _A1 so that the clutch operating oil pressure increases more slowly when the hydraulic pump is rotating at a high speed than when the _hydraulic pump is rotating at a low speed.