JPS6118275Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a pressure regulating valve device for setting the working oil pressure for a hydraulic clutch in a hydraulic clutch type transmission installed in a self-propelled agricultural vehicle, a construction vehicle, etc. A control piston that receives the tip of a hydraulic pressure setting spring and increases the strength of the oil pressure setting spring by advancing the control piston is provided in the valve cage so as to be able to move forward to a regulated position, and a throttle oil passage is connected to the oil supply circuit for the hydraulic clutch. and a pressure regulating valve device provided with a throttle oil passage opening behind the control piston,
It is related to

The pressure regulating valve device configured as described above is known from, for example, Japanese Utility Model Application No. 52-98051, etc., and the switching valve for switching and controlling the supply and discharge of hydraulic oil to and from the hydraulic clutch in a hydraulic clutch type transmission is moved to a neutral position. When the control piston is displaced from one working position or from one working position to another working position, the control piston is gradually advanced by the hydraulic action of the oil supply circuit via the throttle oil passage described above, and the control piston is moved forward for pressure setting. Since the strength of the spring is gradually increased, the hydraulic pressure applied to the hydraulic clutch is gradually increased, and the hydraulic clutch is smoothly engaged to smoothly start the vehicle or change the vehicle speed.

The purpose of this invention is to provide such a pressure regulating valve device, which can form the above-mentioned throttle oil passage in an advantageous way to deal with troubles such as clogging with dirt, and can also gradually increase the oil pressure in accordance with different conditions. An object of the present invention is to provide a novel pressure regulating valve device whose characteristics can be changed.

Regarding the illustrated embodiment, the configuration of the pressure regulating valve device according to the invention will be explained. In FIG. 1 showing the first embodiment, 1 performs a three-speed gear shift in the forward direction of the vehicle and one gear shift in the reverse direction of the vehicle. In a hydraulic clutch type transmission, there are multiple units (not shown in the figure) (four in the case shown).
This is a power shaft shaft on which are mounted idle speed change gears.On this power shift shaft 1, there are installed four free speed change gears for selectively coupling each of the above-mentioned idle speed change gears to the power shaft shaft 1. Hydraulic clutch, i.e.
F ₁ Hydraulic clutch 2F ₁ , 2F ₂ Hydraulic clutch 2F ₂ ,
F ₃ hydraulic clutch 2F ₃ and R hydraulic clutch 2R
is provided. These hydraulic clutches 2F ₁ −
In order to supply the operating shaft from the oil tank 3 to 2R, the hydraulic clutch 2F ₁ -2R is supplied from the oil tank 3.
A hydraulic pump 5 is provided inserted into the oil supply circuit 4 guided in the direction, and a hydraulic clutch 2F ₁ -2R
In order to switch and control the supply and discharge of the operating shaft,
The 2 ports on the primary side are connected to the oil supply circuit 4 and oil tank 3.
In addition, the 4 ports on the secondary side are connected to the hydraulic clutch 2F ₁
-2R, respectively connected switching valves 6 are provided. The switching valve 6 is a fully hydraulic clutch 2F ₁ −
Drain hydraulic oil from 2R and fully hydraulic clutch 2F ₁
-2R is turned off at the neutral position N, and the operating shaft is supplied to the corresponding one hydraulic clutch 2F ₁ , 2F ₂ , 2F ₃ or 2R, and the hydraulic oil is discharged from the other three hydraulic clutches to reduce the hydraulic pressure of the one hydraulic clutch. Clutch 2F ₁ , 2F ₂ , 2
It has a forward first speed position F ₁ , a forward second speed position F ₂ , a forward third speed position F ₃ , and a reverse first speed position R in _which only F 3 or 2R is selectively engaged.

When the switching valve 6 described above is placed in each operating position F ₁ , F ₂ , F ₃ or R, each hydraulic clutch 2F ₁ , 2
In order to set the hydraulic pressure acting on F ₂ , 2F ₃ or 2R, a pressure regulating valve arrangement according to the invention is provided. This pressure regulating valve device is provided with a valve body 8 which is urged to move in the backward direction by a hydraulic pressure setting spring 7 and is slidably inserted into a valve case 9, as is usual. Pump port 10 and relief port 1 of valve case 9
an annular groove 12 for selectively communicating with 1;
A hole 14 is formed to allow the pump port 10 to communicate with the oil chamber 13 at the rear of the valve body 8 at all times. The pump port 10 is connected to the oil supply circuit 4 described above via a connection circuit 15, and the valve body 8 is connected to the oil supply circuit 4 that acts on the oil chamber 13.
The pump is moved forward as shown in the figure against the force of the spring 7 by the hydraulic pressure of the pump, and the pump port 10 and the relief port 11 are communicated through the annular groove 12 to perform a relief operation.

The tip of the oil pressure setting spring 7 is received by a control piston 17 provided in the valve case 9 so as to be able to move forward from the most retracted position shown by the chain line to the position where it abuts the retaining ring 16. This control piston 1
7. Behind the valve case 9, there is an oil chamber 18.
The oil chamber 18 is connected to the supply circuit 4 via the throttle oil passage 19. The control piston 17 has a throttle oil passage 19 which is always open behind the piston 17 when the switching valve 6 is switched to any operating position F ₁ , F ₂ , F ₃ or R. The hydraulic pressure of the oil supply circuit 4 is gradually applied to the rear of the piston 17 to gradually move it forward, thereby gradually increasing the strength of the hydraulic pressure setting spring 7.

As described above, in particular, the control piston 1
A hydraulic accumulator 20 as shown is provided connected to the throttle oil passage 19 on the 7 side. In this hydraulic accumulator 20, on the back side of the spring 23 that urges the piston 22 forward in the direction of sandwiching the hydraulic chamber 21, there is an advancement/retraction rod 24.
is applied, and this advancing/retracting rod 24 is used as an operating lever 25.
By moving the piston 22 forward and backward as shown by the solid line, the movement rod 24 is advanced and the piston 22 is restrained so that it cannot move backward.The piston 22 cannot move backward due to the hydraulic pressure acting on the hydraulic chamber 21, and the function of the hydraulic accumulator 20 is interrupted. is released, and conversely, when the advance/retreat lever 24 is retreated as shown by the chain line, the piston 22 moves into the hydraulic chamber 2.
The oil pressure acting on the hydraulic accumulator 20 is designed to allow the hydraulic accumulator 20 to move backward against the force of the spring 23, that is, to enable the hydraulic accumulator 20 to function. As shown in FIG. 1, the advancing and retracting rod 24 has two detent grooves 24a and 24b at an appropriate interval.
A detent ball 27 is provided which is biased to move by a spring 26, and the advancing/retracting rod 24 has a ball 27 in its forward position.
7 faces the detent groove 24a, and in the retracted position, the ball 27 faces the other detent groove 24b, so that their positions are restrained.

In addition, in the case shown in the figure, a high pressure working port 28 that opens at a suitable location in the above-mentioned hydraulic accumulator 20 is shown.
and a hole 22a with one end opened to the hydraulic chamber 21 and the other end opened to the circumferential surface of the piston 22,
It is formed in the piston 22, and the oil supply circuit 4 is connected to the high pressure working port 28 via the connection circuit 15 and the oil passage 29, so that the hole 24a is usually blocked by the case part of the accumulator 20. When the piston 22 is moved back as shown by the chain line by the hydraulic pressure acting on the hydraulic chamber 21 against the force of the spring 23, the hole 22a opens into the high pressure working port 2.
9, the high pressure working port 24 opens into the hydraulic chamber 2.
1, and the oil pressure of the oil supply circuit 4 is transmitted through the connection circuit 15, the oil passage 29, the high pressure action port 28, the hole 22a, and the hydraulic chamber 21 to the part of the throttle oil passage 19 on the downstream side of the throttle part 19a. It is designed so that it acts without going through the part 19a, thereby eliminating the function of the constricting part 19a. The hydraulic accumulator 20 is also provided with a drain port 30 for draining leaked oil from the spring 23 installation space.

Further, in the illustrated case, an oil drain passage 32 that opens into the oil chamber 18 is formed in the valve case 9, and a valve seat 33 formed in the middle of this oil drain passage 32 is connected to the oil chamber 18.
A valve element 34 is provided which can be seated from the opposite side to block the oil drain passage 32, and a spring 35 that biases the valve element 34 in the opposite direction from seating on the valve seat 33 is installed in a step inside the valve case 9. Part 9a and valve body 3
Both ends are received by the step portion 34a of No. 4. An oil chamber 36 is provided in the valve case 9 behind the valve body 34, and the back surface of the valve body 34, that is, the surface opposite to the oil chamber 18, is placed in the direction in which the valve body 34 is seated on the valve seat 33. It is formed in the pressure receiving part 34b that applies hydraulic pressure for moving and energizing, and the oil passage 2
9 is provided with an extension portion 29a opening into the oil chamber 36, and the oil pressure of the oil supply circuit 4 is applied to the pressure receiving portion 24b. The pressure receiving area _S1 of the pressure receiving part 34b is the oil chamber 1 behind the control piston 17 in the valve body 34.
It is larger than the pressure receiving area S ₂ on the 8 side, and the oil pressure of the oil supply circuit 4 is P, and the valve body 3 of the spring 35
4.If the retreating force is F, then _{the pressure-receiving areas S 1 , S 2} are
The relationship between the spring force F and the spring force F is set.

Since the pressure regulating _valve device according to this invention and shown in _{FIG .} When the valve body 8 is moved forward and performs a relief operation as shown in the figure, the strength of the spring 7, which biases the valve body 8 to move in the backward direction and sets the clutch action oil pressure, increases as described above. Since the hydraulic pressure P of the oil supply circuit 4 and therefore the clutch working pressure P is
For the elapsed time t after the switching of the switching valve 6, the second
As shown in the figure, the pressure is gradually increased to a steady pressure P ₀ corresponding to the strength of the spring 7 at the most advanced position of the piston 17, where the control piston 17 contacts the retaining ring 16. Since the accumulator 20 is provided and its function can be selectively canceled, the oil pressure gradual increase characteristic can be changed as follows.

That is, the hydraulic accumulator 20 has a piston 22 that is retracted against the force of a spring 23 by the hydraulic pressure acting on the hydraulic pressure 21.
The volume of the hydraulic chamber 21 is gradually increased, and oil is supplied to the hydraulic pressure 18 behind the control piston 17 at a rate lower than the oil supply rate determined by the throttle section 19a in the throttle oil passage 19, thereby slowing down the forward speed of the control piston 17 and therefore the rise speed of the clutch operating hydraulic pressure P. 1, when the advance/retract rod 24 is advanced and the function of the hydraulic accumulator 20 is released, the hydraulic pressure P rises only along the relation line C1 with a relatively steep gradient determined by the throttle section 19a, as shown in FIG. 2a. On the other hand, when the advance/retract rod 24 is retreated and the hydraulic accumulator 20 is made to function, as shown in the chain line in FIG. ₁ , the hydraulic pressure rises along the relation line _C2 with a gentle gradient as the ratio of oil supplied to the oil chamber 18 behind the control piston 17 is reduced by the retreating movement of the piston 22 of the hydraulic accumulator 20, as shown in FIG. 2b, for example. As the accumulator piston 22 retreats, the force of the accumulator spring 23 is increased and the retreating movement of the piston 22 becomes minute, so that the hydraulic pressure rise speed is substantially determined by the throttle section 19a, as shown in FIG.
The rise of the hydraulic pressure along _C1 ' is timed to occur before or after the rise of the hydraulic pressure along C1', so that the rise of the hydraulic pressure is slower. In FIG. 2b, the relation line _C3 , which is continuous with the relation line _C1 ', indicates the position where the piston 22 retreats to the position shown by the chain line in FIG.
This is the hydraulic pressure rise characteristic after oil is supplied to the rear of the control piston 17 without passing through the throttle portion 19a as described above. In this state,
Since the oil supply to the rear of the control piston 17 is hardly restricted, the oil pressure P rises almost vertically to the steady pressure P ₀ .

According to the illustrated pressure regulating valve device, as explained above, it is possible to change and control the oil pressure gradual increase or rise characteristic, so it is possible to select whether or not to make the hydraulic accumulator 20 function in accordance with various conditions, and adjust the oil pressure gradual increase characteristic. By changing this, it is possible to obtain a hydraulic pressure rise that meets the conditions.

Thus, for example, an agricultural or construction transport vehicle may have a single hydraulic pressure gradient characteristic even though the weight and therefore the moment of inertia of the vehicle body differ by a factor of two or more when unloaded and loaded. When using a pressure regulating valve device that does not operate, if the oil pressure gradual increase characteristic is set for when the car is empty, the time lag for the clutch operating oil pressure to reach steady pressure when the car is loaded will be excessive, and on steep slopes, the time lag until clutch engagement is achieved will be too long. On the other hand, if the hydraulic pressure gradually increases when the vehicle is loaded, the hydraulic pressure rises too quickly when the vehicle is empty, making it difficult to start the vehicle. In contrast to this situation, according to the illustrated pressure regulating valve device that can switch the oil pressure gradual increase characteristic as described above, the oil pressure rises relatively quickly according to Figure 2 a when loaded, and when empty. The above-mentioned inconvenience can be avoided by allowing the oil pressure to gradually rise according to FIG. 2b. In the case of the above-mentioned transport vehicle, an operating lever 25 for selectively canceling the function of the hydraulic accumulator 20 can be installed in the driver's seat and operated by hand, or the advancing/retracting lever 24 can be moved electromagnetically forward and backward. In addition to the above structure, a center for detecting the presence or absence of a load on the loading platform of a vehicle may be provided to automatically switch the system.

In addition to the above-mentioned cases, when an agricultural vehicle or a construction vehicle is climbing a slope or during excavation work where a large load is applied, the characteristic shown in Figure 2 a is selected to cause the vehicle to start suddenly, and vice versa. When driving on roads or during normal work where the applied load is reduced, the characteristics shown in Figure 2b may be selected to allow the vehicle to start slowly, or a mechanical sub-shift may be used in addition to the hydraulic clutch type transmission. In a vehicle equipped with the device, the auxiliary gear shift lever and the forward/backward lever 24 are arranged so that the characteristics shown in FIG. or, when moving the hydraulic clutch type transmission in the direction of speed increase, the characteristic shown in Fig. 2 a is selected, and when moving it in the direction of deceleration, the characteristic shown in Fig. 2 b is selected. The illustrated pressure regulating valve device can be utilized in various ways, such as by associating the switching valve 6 with the forward/backward lever 24.

Note that the valve body 34 selectively blocking the oil drain passage 32 described above moves toward the valve seat 33 during the rise of oil pressure and in the clutch engaging state shown in FIG. 2, since the relationship of formula 1 described above is satisfied. When the switching valve 6 is returned to the neutral position N and switched between the two working positions, the oil supply circuit 4 is temporarily closed to the oil tank 3.
When the oil pressure is removed from the oil pressure 36 behind the valve body 34, the force of the spring 35 causes the valve body 35 to quickly move backward, leaving the valve seat 33 and blocking the oil drain passage 32. is released, the oil is quickly drained from the oil chamber 18, and the control piston 17 is moved backward.

As shown in Fig. 2b, by rapidly increasing the hydraulic pressure along the almost vertical relationship line _C3 at the end of the hydraulic pressure rising process, it is possible to start the vehicle and change the vehicle speed by clutch engagement. Since this is carried out at a relatively low hydraulic pressure, the steady pressure should be restored immediately after the engagement is completed.
Safe operation of the hydraulic clutch type transmission is achieved so that P ₀ is obtained and stable vehicle running conditions are quickly achieved.

Next, a second embodiment shown in FIG. 3 will be explained. In this other embodiment, the throttle part 1 in the throttle oil passage 19 is
A selector valve 40 as shown is provided between the hydraulic accumulator 9a and the hydraulic accumulator 20. The selector valve 40 has a port connected to the throttle part 19a on the primary side, and a port connected to the oil chamber 18 via the hydraulic accumulator 20 and a port connected to the oil chamber 18 via the hydraulic accumulator 20. The throttle part 19a is connected to the oil chamber 18 via the hydraulic accumulator 20 in the first position, and the throttle part 19a is connected to the oil chamber 18 through the hydraulic accumulator 20 in the first position. Then, the constricted portion 19a is directly connected to the oil chamber 18. Between the hydraulic accumulator 20 and the oil chamber 18,
A check valve 41 is provided to prevent oil from flowing back toward the hydraulic accumulator 20 when the selector valve 40 is placed in the second position.

As described above, also in the second embodiment shown in FIG. 3, the function of the hydraulic accumulator 20 is selectively canceled by moving the selector valve 40 to the second position. Therefore, the pressure regulating valve device according to the second embodiment can also be used in exactly the same manner as described for the pressure regulating valve device according to the first embodiment.

As in the second embodiment shown in FIG. 3, by blocking the flow of oil into the hydraulic chamber 21 of the hydraulic accumulator 20, the backward movement of the accumulator piston 22 is prevented and the function of the hydraulic accumulator 20 is selected. The function canceling means for canceling the function is not limited to the selector valve 40 shown in FIG.
It is also possible to have a structure in which the flow of oil into the hydraulic chamber 21 is blocked by selectively blocking the connection circuit between the hydraulic chamber 21 and the hydraulic chamber 21.

As is clear from the above description, the pressure regulating valve device of the hydraulic clutch type transmission of this invention is a pressure regulating valve device for setting the working oil pressure for the hydraulic clutch in the hydraulic clutch type transmission, and the oil pressure setting spring 7 A control piston 17 that receives the tip of the hydraulic pressure setting spring 7 and increases the strength of the oil pressure setting spring 7 by advancing the control piston 17 is provided in the valve case 9 so as to be able to move forward to a regulated position, and is connected to the oil supply circuit 4 for the hydraulic clutch. Squeezing oil passage 19
The pressure regulating valve device is provided with a throttle oil passage 19 that opens behind the control piston 17, and the throttle oil passage 19 is located closer to the control piston 17 than the throttle portion 19a in the throttle oil passage 19.
A hydraulic accumulator 20 is provided in connection with the piston 2 of this hydraulic accumulator 20.
2 or by blocking the inflow of oil into the hydraulic chamber 21 of the hydraulic accumulator 20 to prevent the backward movement of the piston 22 of the hydraulic accumulator 20.
function canceling means 24 for selectively canceling the function of 0;
40.

In other words, this invention aims to achieve smooth engagement of the hydraulic clutch by gradually increasing the oil pressure, and to smoothly start the vehicle or change the vehicle speed. A hydraulic accumulator 20 is provided which allows the hydraulic pressure to rise at a slower rate than the rate determined by the section 19a, and the function of the hydraulic accumulator 20 can be selectively cancelled. By making the hydraulic accumulator 20 function or not depending on various conditions such as the presence or absence of a live load, running conditions, vehicle speed, type of work to be performed, etc., it is possible to obtain hydraulic pressure gradual increase characteristics suitable for each case. In addition, the pressure regulating valve device of this invention can function the hydraulic accumulator 20 to satisfy such requirements under conditions that require the oil pressure to rise very slowly. The diameter of the throttle portion 19a in the pressure regulating valve device can be made relatively large by adapting to the condition that the oil pressure rises relatively quickly. By enlarging the diameter of the constricted part, clogging due to dust or the like can be prevented, and such clogging can be easily removed by making the constricted part have an enlarged diameter. .

[Brief explanation of the drawing]

Fig. 1 is a schematic vertical cross-sectional side view of the first embodiment of the present invention shown together with a hydraulic circuit, Fig. 2 a and b are schematic graphs showing the operation of the same embodiment, and Fig. 3 is a schematic longitudinal cross-sectional view of another embodiment. They are a side view and a hydraulic circuit diagram. 1...Powershaft shaft, 2F ₁ , 2F ₂ , 2
F ₃ , 2R...Hydraulic clutch, 4...Oil supply circuit,
7... Spring for oil pressure setting, 8... Valve body, 9...
... Valve case, 15 ... Connection circuit, 16 ... Retaining ring, 17 ... Control piston, 18 ... Oil chamber, 19
... Restriction oil passage, 19a ... Restriction part, 20 ... Hydraulic accumulator, 21 ... Hydraulic chamber, 22 ... Piston, 23 ... Spring, 24 ... Advancement and retraction rod,
25...operation lever, 40...selector valve,
41...Check valve.

Claims (1)

[Scope of utility model registration request] This is a pressure regulating valve device for setting the working oil pressure for the hydraulic clutch in a hydraulic clutch type transmission, and has a control piston inside the valve case that receives the tip of the oil pressure setting spring and increases the strength of the oil pressure setting spring by advancing it. , a pressure regulating valve device which is movable forward to a regulated position and is provided with a throttle oil passage that is connected to an oil supply circuit for the hydraulic clutch and that opens behind the control piston; , is connected to the throttle oil passage 19 on the side of the control piston 17 with respect to the throttle part 19a in the throttle oil passage 19, and is provided with a hydraulic accumulator 20, and is mechanically engaged with the piston 22 of the hydraulic accumulator 20. or function canceling means 24, 40 for selectively canceling the function of the hydraulic accumulator 20 by blocking the flow of oil into the hydraulic chamber 21 of the hydraulic accumulator 20 to prevent the piston 22 of the hydraulic accumulator 20 from moving backward; A pressure regulating valve device characterized by being provided with.