JPS6112402Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a hydraulic control device used, for example, to control the hydraulic pressure applied to a hydraulic clutch in a hydraulically operated reversing machine for ships. More specifically, this idea consists of a power piston with a movable spring holder that receives the end of a compression spring for setting oil pressure during pressure reduction, rotatably installed inside the valve case, and an oil chamber behind the power piston. The hydraulic pressure of the oil supply circuit is applied to the oil chamber through the throttle, and when the power piston is moved forward by an amount corresponding to the amount of rotational displacement of the power piston, the oil chamber is filled with oil. A notched groove is formed that communicates with the relief passage and is blocked by the valve case when the power piston is rotated by a certain amount or more, and the pressure is reduced by rotating the power piston by a controlled amount. The present invention relates to a hydraulic control device including a pressure reducing valve configured to control the pressure.

BACKGROUND TECHNOLOGY The above-mentioned type of pressure reducing valve is, for example,
Publication No. 78125, Japanese Unexamined Patent Application Publication No. 147252/1983, Japanese Unexamined Patent Publication No. 147252
This is known from Japanese Patent Laid-open No. 53-30536 and Japanese Patent Application Laid-Open No. 53-83128, and in these publications, a pressure reducing valve of the above type is integrally combined with a switching valve that switches and controls the direction of hydraulic action. This type of pressure reducing valve advances the power piston by a controlled amount by hydraulic action by rotating the power piston described above, and changes and controls the spring force of the compression spring for setting the oil pressure during pressure reduction accordingly. ,
The degree of pressure reduction is adjusted, for example, when a fishing boat is trolling, a hydraulic pressure lower than the normal hydraulic pressure set by a primary pressure regulating valve is applied to a hydraulic clutch in a hydraulically operated reversing machine to cause the hydraulic clutch to slip.

Problems to be Solved by the Invention As shown in the above-mentioned publications, conventional pressure reducing valves of this type have a normal working pressure of 15 kg/cm ² for hydraulic clutches, etc. The system is designed to reduce pressure only by the pressure reducing valve itself, even to low oil pressures such as 2.5Kg/ ^cm2 , and even when the pressure reducing valve is activated, the discharge side oil pressure of the hydraulic pump is maintained at the normal operating oil pressure and the pump is activated. The problem was that the power consumption was relatively large, resulting in large energy losses.

Therefore, this idea was developed to reduce the energy loss during operation of the above-mentioned type of pressure reducing valve by idealizing the rise of the hydraulic pressure at the start of normal hydraulic action on the hydraulic clutch, etc., so that the hydraulic clutch, etc. can operate smoothly without shock. A new hydraulic system has been adopted in conjunction with the structure to be activated, and has a simple structure that reduces energy loss during the operation of the pressure reducing valve and allows smooth activation of the hydraulic clutch, etc. when the normal hydraulic operation starts. It is intended to provide a control device.

Technical measures taken to solve the problem As mentioned at the beginning, this invention was based on a hydraulic control device,
In other words, as illustrated in the attached drawing, a movable spring bearing that receives the end of the compression spring 20 for setting the oil pressure during pressure reduction is configured in the power piston 19 and is rotatably provided in the valve case 1.
An oil chamber 43 is formed behind the oil chamber 43, and the hydraulic pressure of the pump port 8 is applied to the oil chamber 43 through a throttle 45, and the power piston 19 is moved by an amount corresponding to the amount of rotational displacement of the power piston 19. The notch groove 27 is a notch groove 47 that communicates the oil chamber 43 with the oil relief path 46 when the power piston 19 is moved forward by a certain amount, and is blocked by the valve case 1 when the power piston 19 is rotated by more than a certain amount. A hydraulic control device is provided with a pressure reducing valve (including a piston 18 functioning as a valve body) configured to rotate the power piston 19 by a controlled amount to control the degree of pressure reduction. It depends.

In such a hydraulic control device, in order to solve the above-mentioned problems, this invention has a piston 50 that receives the end of the compression spring 17 for setting the normal oil pressure, as illustrated in FIG. 1 and FIGS. 8a and 8b. The primary pressure regulating valve (equipped with the valve body 16) is mounted in the valve case 1 so that the back surface of the piston 50 faces the oil chamber 43 behind the pressure reducing valve power piston 19.
We took technical measures such as arranging pressure reducing valves in series within the

Although the illustrated hydraulic control device is constructed by integrally combining a pressure reducing valve and a switching valve (including a rotor 4), the switching valve and the pressure reducing valve may be provided separately.

Function In the present hydraulic control system, the function of the pressure reducing valve is the same as in the conventional one, and when the power piston 19 is rotationally displaced within the range where the notch groove 27 is not blocked, the piston moves to a position corresponding to the amount of rotational displacement. 19 is moved forward, and the compression spring 20 of the pressure reducing valve takes a spring load corresponding to the position of the piston 19. Therefore, by changing the amount of rotational displacement of the power piston 19, the spring load of the compression spring 20 can be reduced. The degree of pressure reduction of the pressure reducing valve can be adjusted through change control.

On the other hand, when the power piston 19 of the pressure reducing valve is largely rotated and the notch groove 47 of the piston 19 is blocked by the valve case 1 in order to apply normal oil pressure to the hydraulic clutch etc., the following effect is obtained. .

In other words, at this time, the power piston 1 of the pressure reducing valve
9 and the piston 50 that receives the end of the compression spring 17 of the primary pressure regulating valve.
3, the hydraulic pressure of the pump port 8 is gradually applied via the throttle 45. At this time, first, based on the fact that the spring force of the compression spring 20 of the pressure reducing valve is gradually smaller than the spring force of the compression spring 17 of the primary pressure regulating valve, only the power piston 19 is gradually moved by the oil pressure of the oil chamber 43.
It is advanced to the most advanced position as illustrated in FIG. 8a. As the power piston 20 moves forward in this way, the compression spring 17 of the primary pressure regulating valve is not compressed at all, so the power piston 20 gradually advances from the position shown in FIG. 1 to the position shown in FIG. 8 a. During the time _t1 , the horizontal axis is the time from the point of rotation of the power piston 20, and the vertical axis is the hydraulic pressure established by the primary pressure regulating valve, as shown in Fig. 9. , a constant oil pressure _P1 corresponding to the force of the compression spring 17 when the valve body 16 of the primary pressure regulating valve is retreated to the relief operation position is maintained. In addition, FIG. 9 shows that the illustrated power piston 19 is operated to rotate in one direction and the other direction from a neutral position together with the rotor 4 constituting the switching valve.
In each case, the power piston 19 is rotated largely in one direction and in the other direction, corresponding to the fact that it is configured to be moved forward from the most retracted position shown in FIG. It is said to be a diagram illustrating how the oil pressure rises over time.

When the power piston 19 is moved forward to the most forward position shown in FIG.
The hydraulic pressure of the oil that gradually flows into the valve body causes the valve body to gradually move forward in the direction of the valve body 16 to the most advanced position shown in FIG. 8b. During the time _t2 from the state shown in FIG. 8a to the state shown in FIG. 8b, the compression spring 17 is gradually compressed by the advance of the piston 50, and the spring load is gradually increased. As shown in Fig. 9, the oil pressure is gradually increased from _P1 to the normal oil pressure _P2 .

That is, after the rotational displacement of the power piston 19, the primary pressure regulating valve quickly establishes a low oil pressure P1 corresponding to the force of the compression spring 17 corresponding to the amount of retraction of the valve body ₁₆ to the relief position, and first rapidly applies pressure to the hydraulic clutch etc. Apply low oil pressure P ₁ and then for a certain period of time t ₁
In this case, the hydraulic clutch and the like are operated so to speak at the low oil pressure _P1 , and then the clutch operating oil pressure is gradually increased to the normal oil pressure _P2 at a certain time _t2 .

When a pressure reducing action is applied to the pressure reducing valve, the power piston 19 of the pressure reducing valve is biased backward by the compression spring 20 and vibrates back and forth by a small width to a position corresponding to the amount of rotational displacement of the power piston 19, thereby opening the oil chamber 43 and the oil relief passage. 4
Since the position is maintained while intermittent communication between the pump port 8 and the pump port 8, the oil pressure established in the oil chamber 43, which is communicated with the pump port 8 through the throttle 45, is due to the force of the compression spring 20 of the pressure reducing valve. A correspondingly lower oil pressure results in the piston 50 of the primary pressure regulating valve assuming its most retracted position as shown in FIG. 1 due to its compression spring 17. Therefore, the hydraulic pressure established in the pump port 8 is established by the relief operation of the valve body 16 while the compression spring 17 of the primary pressure regulating valve is fully extended, as shown in FIG. The oil pressure becomes _P1 . In Fig. 9, the hydraulic pressure Pd ₁ and
Pd ₂ shows an example of the pressure reduction oil pressure range during the pressure reduction operation, but from the above, the pressure reduction valve has a range from the relief pressure P ₁ of the primary pressure regulation valve when the compression spring 17 of the pressure regulation valve is fully extended. Decompression hydraulic range Pd ₁ −
It is extremely capable of reducing the oil pressure by an extremely small value, even to the oil pressure between Pd and ₂ .

Embodiment To explain an embodiment, numeral 1 in the figure is a valve case, and a head 2 for forming an oil passage is attached to this valve case 1. In the case shown,
Inside the valve case 1 are a pair of forward hydraulic clutches CF for ships, shown as hydraulic cylinders in FIG.
a switching valve that switches and controls the supply and discharge of hydraulic oil to and from the reverse hydraulic clutch CR;
It incorporates a primary pressure regulating valve that sets the working oil pressure for CF and CR, and a pressure reducing valve that appropriately reduces the set oil pressure to this primary pressure regulating valve and applies it to the hydraulic clutches CF and CR. Of these, the switching valve is equipped with a rotor 4 that is rotationally operated by an operating lever 3, and this rotor 4 is rotated by the clutch ports 5F and 5R of the head 2.
(Fig. 3), the clutch port 7 of the valve case 1 is communicated with the oil passages 6F and 6R in the head 2.
F, 7R (Figs. 3 and 5) are connected to the pump port 8 (Fig. 1) of the head 2 through an oil passage 9 in the head 2, and a pump port 10 of the valve case 1.
(Figures 1 and 4) and tank port 11 of head 2
(Fig. 1), the tank port 13 (first
(Fig.) are appropriately communicated with each other as described below. The primary pressure regulating valve also includes a valve body 16 that intermittently communicates between another pump port 14 formed in the valve case 1 and a relief port 15 (FIG. 1). As shown in the figure, it is biased to move in the direction of blocking the space between the ports 14 and 15 by a compression spring 17 for setting the normal oil pressure. Further, the pressure reducing valve includes a piston 18 fitted into the rotor 4 which is formed into a hollow shape with an open rear end, and a power piston whose front end is fitted into the rotor 4 and inserted into the valve case 1. 19
and the above-mentioned piston 18 and power piston 19
The pressure reducing valve is provided with a compression spring 20 that sets the oil pressure at the time of pressure reduction, which is provided with both ends received by the pressure reducing valve. The power piston 19 is advanced by a controlled amount and the spring force of the compression spring 20 is changed in accordance with the amount of advancement, thereby controlling the degree of pressure reduction. As shown in FIG. 3, the clutch ports 5F and 5R of the head 2 are connected to hydraulic clutches CF and CR, and as shown in FIG. Each is connected to a hydraulic pump P and an oil tank T. Further, as shown in FIG. 1, the pump port 14 of the valve case 1 is connected to the hydraulic pump P, and the relief port 15 of the valve case 1 is connected to the secondary pressure regulating valve 21.
are connected to the oil tank T via the
From the front stage side of the secondary pressure regulating valve 21, the required lubricated part L
A guide oil passage 22 is led out using hydraulic oil set by a secondary pressure regulating valve 21 as lubricating oil.

In order to explain the structure of the switching valve equipped with the rotor 4, the rotor 4 has a pump port 10 of the valve case 1, as shown in FIGS. 1, 4, and 6. A narrow slit groove 23 over a certain angle range at the opening position
are formed on the outer peripheral surface, and a pair of oil holes 24, which open into the hollow part of the rotor 4 at both ends of the slit groove 23 at an annular groove 4b on the inner peripheral surface of the rotor 4.
25, both in the neutral position N shown in FIG. 4a and in the working positions F,
Also in R, the pump port 10 is always communicated with the hollow portion of the rotor 4 via the slit groove 23 and at least one of the oil holes 24 and 25. As shown in FIGS. 1, 5 and 6, the rotor 4 also has clutch ports 7F and 7 of the valve case 1 when viewed in the axial direction of the rotor 4.
At the opening position of R, a slot 26 is formed on the outer peripheral surface over a certain angular range, and a pair of other slots 27F and 27R are formed on the outer peripheral surface over a certain angular range on both sides of this slot 26. has been formed,
Oil holes 28F, 28R opening into the hollow portion of the rotor 4 are formed at one ends of the other slots 27F, 27R, so that the other slots 27F, 27R are always communicated with the hollow portion of the rotor 4. Furthermore, as shown in FIGS. 1 and 6, the rear end of the rotor 4 is connected to the valve case 1.
It is formed in a small diameter part 4a that provides an annular gap 29 in the valve case 1 at the opening of the tank port 13, and an annular slot 30 is formed on the outer peripheral surface of the rotor 4 at a position slightly forward of this small diameter part 4a. A slot 31 that always communicates between the annular slot 30 and the gap 29, and a slot 32 that always communicates between the annular slot 30 and the slot 26 at the clutch ports 7F and 7R are connected to the rotor. 4 The rotor 4 is attached to the outer peripheral surface.
They are formed along the axial direction of each.

From the above, the slots 26 at the clutch ports 7F and 7R are the slots 32, annular slots 30, and slots 3.
1 and always via the annular gap 29 tank port 1
3, but the slot 26 communicates with the fifth
At the neutral position N of the rotor 4 shown in FIG.
In this case, it is communicated only to clutch port 7R,
Conversely, the backward motion position R of the rotor 4 shown in FIG.
In this case, the rotor 4 is formed in such an angular range and phase that it communicates only with the clutch port 7F. In addition, a pair of other slots 27F and 27R at the clutch ports 7F and 7R are located at both clutch ports 7F and 7R in the neutral position N shown in FIG. 5a.
At the forward working position F of the rotor 4 shown in FIG. 5b, the slot 27F is connected to the clutch port 7F, and at the backward working position R of the rotor 4 shown in FIG. 5c, the slot 27R is connected to the clutch port 7F. The rotor 4 is formed in an angular range and a phase such that the ports 7R communicate with each other. Further, the piston 18 fitted into the hollow part of the rotor 4 has an annular oil passage 33 formed in the hollow part of the rotor 4 on the outer periphery of the piston 18, as shown in FIGS. 1 and 3-5. A small diameter portion 18a is formed between the opening position of the pump port 10 and the opening positions of the clutch ports 7F and 7R when viewed in the axial direction of the rotor 4.

The configuration required for the switching valve is as described above,
At the neutral position N of the rotor 4 shown in FIGS. 1 and 3, FIGS. , 28R, the slots 27F and 27R at the clutch ports 7F and 7R are cut off from the clutch ports 7F and 7R as shown in FIG.
A clutch port 7 that is constantly in communication with the tank port 13 through the slot 32, the annular slot 30, the slot 31, and the annular gap 29 on the outer periphery of the rotor small diameter portion 4a.
Slots 26 at positions F and 7R communicate with both clutch ports 7F and 7R, as shown in FIG. 5a.
Therefore, oil is drained from both hydraulic clutches CF and CR to the oil tank T, and the oil is drained from both hydraulic clutches CF and CR to the oil tank T.
CF and CR take a detached state.

In the forward operating position F of the rotor 4 shown in FIGS. 4b and 5b, the pump port 1 is
The slot 27F, which is always in communication with the clutch port 7F, is in communication with the clutch port 7F, as shown in FIG.
Similarly, as shown in Fig. 5b, the clutch port 7R
It is communicated to. Therefore, hydraulic oil is supplied to the forward hydraulic clutch CF, hydraulic oil is drained from the reverse hydraulic clutch CR, and only the forward hydraulic clutch CF is fitted.

Conversely, in the backward movement position R of the rotor 4 shown in FIGS. 4c and 5c, the slot 27R, which is constantly in communication with the pump port 10, is connected to the clutch port 7R, as shown in FIG. 5c. At the same time, the slot 26, which is always in communication with the tank port 13, is made to communicate with the clutch port 7F. Therefore, the hydraulic clutch for reverse
While hydraulic oil is supplied to CR, hydraulic oil is drained from the forward hydraulic clutch CF, and only the reverse hydraulic clutch CR is fitted.

In FIG. 1 and FIGS. 3-5, 34 is a thrust bearing 35 disposed between the rotor 4 and the valve case 1 as shown in FIG.
This is a lubricating oil passage formed on the outer peripheral surface of the rotor 4 along the axial direction of the rotor 4 so as to lead lubricating oil from the rotor 4.

Next, to explain the structure of the pressure reducing valve equipped with the piston 18, the power piston 19, and the compression spring 20 as described above, as shown in FIG. A first oil chamber 36 is formed by a hole 18b drilled in the piston 18 from the front end side, and a second oil chamber 37 is formed in the hollow part of the rotor 4 between the power pistons 19. It is formed. As shown in FIGS. 1 and 5, a pair of oil holes 38 are formed in the piston 18 to communicate the annular oil passage 33, which is always in communication with the pump port 10, with the first oil chamber 36. At the same time, a throttle oil hole 39 that communicates between the first oil chamber 36 and the second oil chamber 37 is similarly formed in the piston 18, and the second oil chamber 37 is always connected to the tank port 13 as described above. An oil hole 40 is formed in the rotor 4 to communicate with the annular groove 30 on the outer peripheral surface of the rotor 4. Further, as shown in FIG. 1, a slot 41 of a certain length along the axial direction of the piston 19 is formed on the outer peripheral surface of the front end of the power piston 19, and a pin 42 supported by the rotor 4 is inserted into the slot 41. By facing the power piston 19, the power piston 19 is connected to the rotor 4 so that it cannot rotate relative to the rotor 4 but can freely slide relative to the rotor 4. moreover,
Similarly, as shown in FIG.
An oil chamber 43 is formed in the valve case 1 at the rear, and this oil chamber 43 connects to the pump port 8 of the head 2, an oil passage 44 in the head 2, and a throttle oil passage 45 formed in the valve case 1. It is communicated via.

As shown in FIG. 1, an oil relief passage 46 for communicating the oil chamber 43 with the tank port 13 is formed in the valve case 1 at a position slightly forward of the oil chamber 43. And the 1st and 7th
As shown in the figure, a notch groove 47 is formed on the outer circumferential surface of the power piston 19 so that the groove depth d along the axial direction of the piston 19 gradually becomes shallower from position N to each side in the circumferential direction. It is formed over a certain range. This cutout groove 47 is formed at the deepest part 47a when the power piston 19, which is rotationally displaced together with the rotor 4 via the pin 42, is at a rotational position corresponding to the neutral position N of the rotor 4 shown in the figure.
are formed so as to be in phase with the oil relief passage 46. Therefore, when the rotor 4 is rotated from the neutral position N to the working positions F and R to obtain the corresponding rotational displacement of the power piston 19, the power piston 19 is moved forward a certain distance by the hydraulic pressure acting on the oil chamber 43. When the oil chamber 43 is opened, the oil chamber 43 is brought into communication with the oil relief passage 46 through the notch groove 47, and the power piston 19 is moved forward by an amount corresponding to the rotational displacement position of the power piston 19. The above-mentioned notch groove 47 is
When the rotor 4 is fully rotationally displaced in the direction of each operating position F and R to obtain a corresponding rotational displacement of the power piston 19, the notch groove 47 is removed from the oil relief passage 46 in the circumferential direction, and the notch groove 47
and the oil relief passage 46 is blocked by the inner circumferential surface of the valve case 1, and the oil chamber 43 is completely cut off from communicating with the oil relief passage 46 through the notch groove 47. So, power piston 1
It is formed on the outer peripheral surface of 9. Also piston 18
The oil hole 40 for communicating the second oil chamber 37 between the power piston 19 and the power piston 19 to the tank port 13 allows the rotor 4 to be fully rotated from the neutral position N to each operating position F and RR direction, The power piston 19 is formed in the rotor 4 at a position where it is blocked by the power piston 19 when the power piston 19 is moved forward to the maximum extent.

The configuration required for the pressure reducing valve is as described above,
When the rotor 4 is rotationally displaced by a certain amount in either the operating position F or R direction by the operating lever 3, and the power piston 19 is correspondingly rotationally displaced by a certain amount in the same direction, the oil passage 44 and the throttle oil passage are 45
The oil pressure of the pump port 8, which gradually acts on the oil chamber 43 behind the power piston 19 through the oil pressure, moves the power piston 19 to a position where the oil chamber 43 communicates with the oil relief passage 46 through the notch groove 47. , the rotor 4 and the power piston 19 are moved forward by an amount corresponding to the amount of rotational displacement. Therefore, it is received by the power piston 19. The compression spring 20 of the pressure reducing valve moves the rotor 4 from the neutral position N to each operating position F, R direction.
The rotor 4 is moved forward by a power piston 19 that is moved forward by an amount corresponding to the amount of rotational operation.
Depending on the amount of rotational operation, the greater the amount of rotation, the greater the compression and the higher the spring force.

On the other hand, the first oil chamber 36 on the front side of the piston 18 is communicated with the annular oil passage 33, which is always in communication with the pump port 10, through the oil hole 38, as described above. The hydraulic pressure of the pump port 10 is applied to the first oil chamber 36, and the piston 18 is
Since the oil is drained only gradually to the second oil chamber 37 through the throttle oil hole 39, the oil pressure in the first oil chamber 36 is higher than the oil pressure in the second oil chamber 37. The hydraulic pressure of the first oil chamber 36 resists the force of the spring 20, and as shown by the chain line in FIG. 1, the inner circumferential surface of the rotor 4 is The upper annular groove 4b
The rear end is moved back to a position where the annular oil passage 33 is blocked. In this way, the annular oil passage 3
3 is blocked closer to the pump port 10 than the oil hole 38, the pump port 10 and the first oil chamber 36 are blocked.
Although the communication between the clutch port 7F or 7R is cut off, the first oil chamber 36 is connected to the tank port 1.
The piston 18 is placed in the second oil chamber 37 communicating with the piston 3.
are communicated through the throttle oil hole 39,
Since oil is gradually drained from the first oil chamber 36 and there is also some oil leakage from the hydraulic clutches CF and CR, the oil pressure in the first oil chamber 36 is decreasing. Therefore, the piston 18 is moved forward slightly by the force of the compression spring 20, thereby unblocking the annular oil passage 33, and
The oil pressure from the pump port 10 is again applied to the first oil chamber 36, and the piston 18 is moved back so as to perform the above-mentioned blocking again. After that, the same process is repeated, and piston 1
8 repeats blocking and unblocking of the annular oil passage 33 by vibrating back and forth. For this reason, the annular oil passage 33, and thus the passage 3 with four rotations of the rotor.
A hydraulic pressure equivalent to the force of 20 compression springs is established in the clutch port 7F or 7R, which is connected to the clutch port 7F or 7R, and this hydraulic pressure is applied to the forward hydraulic clutch CF or the reverse hydraulic clutch CR. .

The spring force of the compression spring 20 is set to be smaller than the spring force of the compression spring 17 of the primary pressure regulating valve. Therefore, the oil pressure when the pressure reducing valve is activated is gradually lower than the normal oil pressure caused by the primary pressure regulating valve, and the required pressure reduction is achieved by the pressure reducing valve, and the hydraulic clutches CF and CR are selectively operated by the action of the pressure reducing valve. This allows smooth slip operation. The degree of pressure reduction by the pressure reducing valve is determined by moving the rotor 4 from the neutral position N to each operating position F,
The power piston 19 is moved forward in accordance with the rotational displacement amount in the R direction, and the compression spring 20 is compressed by an amount corresponding to the rotational displacement amount to increase the spring force of the spring 20.
The operating position of the rotor 4 can be changed and adjusted by the amount of rotational operation in the F and R directions. Then, when the rotor 4 is fully rotated in the direction of each operating position F and R, the power piston 19 advances accordingly, blocking the oil hole 40 as described above, and opening the tank port 13 of the second oil chamber 37. The communication with the piston 18 is cut off, the oil drain from the second oil chamber 37 disappears, and the oil pressures in the first oil chamber 36 and the second oil chamber 37 become equal, so that the piston 18 is compressed. It is moved forward by the action of the spring 20, the pressure reducing valve function is released, and the normal oil pressure set by the primary pressure regulating valve is applied to each hydraulic clutch CF, CR.

In the illustrated case, as shown in FIG.
The base end of the compression spring 48 is received by an adjusting screw 49 supported by the rotor 4. Therefore, by screwing the adjustment screw 49 and moving it forward and backward, the spring force of the weak compression spring 48 can be adjusted, and the piston 1 can be adjusted.
8, the initial spring force of the compression spring 20 of the pressure reducing valve can be adjusted, and by this adjustment, the pressure reducing range of the pressure reducing valve can be adjusted.

Here, the configuration of the primary pressure regulating valve including the valve body 16 and the compression spring 17 will be explained.
As shown in the figure, the end of the compression spring 17 is received by a piston 50 provided within the valve case 1. In particular, this piston 50 is arranged so that the back surface of the piston 50 faces the oil chamber 43 behind the pressure reducing valve power piston 19, and the valve case 50 is
A pressure reducing valve and a primary pressure regulating valve are arranged in series within the valve case. The retracted position of the piston 50 is regulated by a retaining ring 51 on the inner peripheral surface of the valve case 1 . In addition, in Figure 1, 52
is a tank port for draining leaked oil from the space inside the valve case 1 between the valve body 6 and the piston 50.

With the above configuration, the rotor 4 can be rotated fully in the direction of each operating position F and R without using a pressure reducing valve, thereby causing a large rotational displacement of the power piston 19 of the pressure reducing valve. , when the normal oil pressure set by the primary pressure regulating valve is selectively applied to each hydraulic clutch CF, CR,
The effect described above in the section of the effect of the device can be obtained.

Therefore, the low oil pressure P ₁ shown in FIG. 9 is first rapidly applied to each hydraulic clutch CF, CR, and then for a certain period of time _{t 1} the hydraulic clutches CF, CR are A hydraulic clutch that has been run-in, and then the clutch operating oil pressure is gradually increased to the normal oil pressure P ₂ for a certain period of time t ₂ .
CF and CR can be completely inserted without any shock.

Further, the rotor 4 is rotationally displaced by an appropriate amount in the direction of the operating position F or R, whereby the power piston 19
When the notch groove 47 is rotationally displaced in the same direction within the range where it is not blocked by the valve case 1, the pressure reducing valve performs a pressure reducing action, and the hydraulic clutches CF and CR are operated in a slip manner, this is also a function of the invention described above. As shown in FIG. 9, the pressure reducing valve acts to reduce the oil pressure by an extremely small value, from the low oil pressure P ₁ to the oil pressure in the reduced oil pressure range Pd ₁ - Pd ₂ , as shown in FIG. The power consumption of the hydraulic pump P (FIG. 1) when the pressure reducing valve is activated is greatly reduced compared to the case where a reduced pressure and low oil pressure is obtained by greatly reducing the pressure from the normal oil pressure.

Effects of the invention In a hydraulic control system equipped with a pressure reducing valve having the structure described above, the piston 50 that receives the end of the compression spring 17 of the primary pressure regulating valve for setting the normal oil pressure is compressed for setting the pressure reducing oil pressure of the pressure reducing valve. By providing the power piston 19, which receives the end of the spring 20 and allows the spring load of the spring 20 to be changed, facing the oil chamber 43 for forward displacement, the pressure is reduced when the pressure reducing valve is activated, as described above. The valve is at a low oil pressure established by the relief operation of the primary pressure regulating valve when the normal oil pressure setting spring 17 is at its maximum extension (low oil pressure P ₁ as shown in FIG. 9), that is, when the spring 17 is at its maximum contraction. In this situation, the pressure reduction action will be performed from a hydraulic pressure that is gradually lower than the normal oil pressure (normal oil pressure P ₂ as shown in Fig. 9) that will be established by the relief operation of the primary pressure regulating valve, and the pressure reducing valve will be activated. When trying to apply normal oil pressure to a hydraulic clutch or the like without causing the pressure to drop, the above-mentioned low oil pressure P ₁ established by the relief operation of the primary pressure regulating valve when the compression spring 17 of the primary pressure regulating valve is in its fully extended state is reduced. The valve power piston 19 is gradually advanced for a certain period of time (time t ₁ as shown in FIG. 9), and then the primary pressure regulating valve piston 50 is gradually advanced for a certain period of time (time t 1 as shown in FIG. 9). It takes a period of time t ₂ ) as shown in FIG. 9 to raise the hydraulic pressure applied to the hydraulic clutch and the like to the above-mentioned normal hydraulic pressure P ₂ .

Therefore, according to this invention, the oil pressure on the discharge side of the hydraulic pump is maintained at a low oil pressure _P1 when the pressure reducing valve is activated, and the power consumption of the pump is gradually reduced compared to the conventional one, and energy loss is reduced. When trying to operate a hydraulic clutch, etc. at the normal oil pressure, a break-in operation is performed at a low oil pressure P ₁ for a certain period of time t ₁ , and then the oil pressure gradually rises to the normal oil pressure P ₂ to completely prevent shock. When the hydraulic clutch is activated, it is possible to smoothly start the operation of the hydraulic clutch, which is considered to be ideal.

Moreover, this idea is based on the pressure reducing valve power piston 19.
The piston 50 of the primary pressure regulating valve is connected to the rear oil chamber 43.
The oil chamber 43 is used as a common oil chamber for applying hydraulic pressure to both the pistons 19 and 50, and the oil chamber 43 is connected to the pump port 8.
Since the throttle 45 in the oil passage connected to the pump is also used as a throttle to gradually apply the hydraulic pressure of the pump port 8 to each piston 19, 50, the above-mentioned remarkable effect can be achieved. It has become possible to play with a simple structure.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view showing an embodiment of this invention, Fig. 2 is a front view of the same embodiment, Fig. 3 is a sectional view taken along the - line in Fig. 1, and Figs. 4 a, b, c. are respectively sectional views taken along the - line in FIG. 1, FIGS. 5 a, b, and c are sectional views taken respectively along the - line in FIG. 1, and FIG. FIG. 7 is a perspective view of another member in the same embodiment, FIGS. 8a and 8b are longitudinal sectional side views showing a part of the same embodiment, and FIG. 9 is for explaining the operation of the same embodiment. A schematic graph appears. 1...Valve case, CF, CR...Hydraulic clutch,
3...Operation lever, 4...Rotor, 5F, 5R
...Clutch port, 7F, 7R...Clutch port, 8...Pump port, 10...Pump port, 11...Tank port, 13...Tank port, 14...Pump port, 15...Relief port, 16 ... Valve body, 17 ... Compression spring,
18... Piston, 19... Power piston, 2
0... Compression spring, 23... Slit groove, 2
4, 25...Oil hole, 26...Slot hole, 27F, 27
R...Slot, 29...Gap, 30...Annular slot,
31...Slot hole, 32...Slot hole, 33...Oil passage,
36...First oil chamber, 37...Second oil chamber, 38
... Oil hole, 39 ... Squeezing oil hole, 40 ... Oil hole, 4
1...Slot hole, 42...Pin, 43...Oil chamber, 44
... Oil passage, 45 ... Squeezing oil passage, 46 ... Oil relief passage, 47 ... Notch groove, 50 ... Piston, 51 ... Retaining ring, 53 ... Stopper surface.

Claims (1)

[Scope of utility model registration request] A movable spring holder that receives the end of a compression spring for setting oil pressure during pressure reduction is configured as a power piston and rotatably provided inside the valve case. An oil chamber is formed behind the power piston, and a pump is installed in the oil chamber. A notched groove that applies hydraulic pressure of the port through a throttle and communicates the oil chamber with an oil relief path when the power piston is moved forward by an amount corresponding to its rotational position. The valve case is configured to form a cutout groove that is blocked by the valve case when the power piston is rotated by a certain amount or more, and the degree of pressure reduction is controlled by rotating the power piston by a controlled amount. A hydraulic control device equipped with a pressure reducing valve, in which the primary pressure regulating valve, in which the end of a compression spring for setting the normal oil pressure is received by a piston, is arranged such that the back surface of the piston faces the oil chamber behind the pressure reducing valve power piston. This hydraulic control device is characterized by being placed inside the valve case and in series with the pressure reducing valve.