JPS628651Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a switching valve device in a hydraulic clutch.

The present invention has a spool housing of a hydraulic clutch switching valve in which one of the three clutches is connected to the pump independently, the other two are connected to the tank, and the pump is connected to the tank during clutch switching. To provide a switching valve device for a hydraulic clutch that reduces the number of ports, reduces the spool diameter, and shortens the spool overall length without creating a hollow hole by arranging ports for each oil passage. This is the purpose.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the outlet of a hydraulic pump 3 driven by a motor is connected to a forward/reverse switching valve 1 via oil passages P ₂ , P ₄ , and the longitudinal switching valve 1 is connected to oil passages P ₁ to _{P 5} .
It is connected to the speed switching valve 2 via. Said oil path P ₁ ~
A relief valve 16 and a quick return valve 17 are connected to _P5 . The four outlets of the speed switching valve 2 are respectively connected to a first clutch oil passage 6', a second clutch oil passage 7', and a third clutch oil passage 7'. The lubricating oil passage 24 is connected to one type of clutch group having a plurality of clutches consisting of a first gear clutch 6, a second gear clutch 7, and a third gear clutch 8 through a passage 8' and a low pressure port L, respectively. Note that _P1 is a low-pressure oil passage that always connects the low-pressure port L and the check valve 5 for generating lubrication oil pressure.

The forward/reverse switching valve 1 is connected to a group of other types of clutches including a plurality of forward clutches 9 and reverse clutches 10 via oil passages 9', 10'.

Each of the oil passages 6', 7', 8', 9', 10' includes
Pilot oil passages 11', 12', 13', respectively.
14', 15' to each of the clutches 6, 7,
8, 9, 10 lubricating oil switching valves 11, 12, 13,
14 and 15 are connected. The lubricating oil switching valve 11
-15 are connected to the lubricating oil passage 24, the low pressure port L, the oil passage _P1 , and the check valve 5 for generating lubricating oil pressure, which serves as a pilot pressure generating device that generates a weak clutch pressure in one of the clutch groups 6, 7, and 8. , connected to tank 4.

Oil passages 9' and 10' leading to the forward clutch 9 and reverse clutch 10 and pilot oil passages 14' and 15' of the forward clutch lubricating oil switching valve 14 and the reverse clutch lubricating oil switching valve 15 are connected directly to the tank 4. .

Each of the switching valves 11 to 15 has a valve body formed by a small piston 25 shown in FIG. 2, as will be described in detail later.

The clutches 6, 7, 8, 9, and 10 all have the same structure as shown in FIG. A is
A clutch disk D is spline-fitted to the clutch shaft. A piston 22 is slidably fitted into the disk D, and a hydraulic chamber 27 is formed between the piston 22 and the disk D. piston 2
2 is the inner race 2 fitted to the clutch shaft A
The return spring 20 is compressed between the return spring 20 and the spring receiver 29 that is in contact with the disk D. 23 is a clutch plate.

A cylindrical portion 30 extends from the inner peripheral edge of the piston 22, and a lubricating oil passage 31 and a spring receiver 32 are formed in the cylindrical portion 30. A small piston 25 having a lubricating oil passage 26 is slidably disposed between the piston cylindrical portion 30 and the clutch shaft A, and the small piston 25 is compressed between the spring receiver 32 and the spring receiver 32. The return spring 21 urges the disc D to abut against the wall. B is clutch shaft A
This is a lubricating oil passage opened on the outer cylinder surface of the clutch, and C is a clutch oil passage.

When the clutch is closed, as shown in the upper half of the clutch shaft centerline O-O, the lubricating oil passage B is mostly covered by the small piston 25, and the lubricating oil lubricates the clutch plate 23. There is.

When pressure oil is introduced from the clutch oil passage C of the clutch shaft A, the small piston 25 slides against the force of the spring 21, and the lubricating oil hole 26 of the small piston 25 slides.
communicates with the lubricating oil passage B at a wide opening, and a large amount of lubricating oil flows to the clutch plate 23. On the other hand, small piston 25
, pressure oil is introduced into the hydraulic chamber 27 from the clutch oil passage C, and the piston 22 is moved by the spring 2.
Move the clutch plate in the direction of the clutch plate 23 against the force of 0,
The clutch is connected as shown in the lower half of the clutch axis center line O--O in FIG. When the oil pressure in the clutch oil passage is released, the piston 22 and the small piston 25 are returned to their original positions by the return springs 20 and 21.

When the forward/reverse switching valve 1 is in a neutral state, the pressure oil discharged from the pump passes through the forward/reverse switching valve 1, passes through each lubricating oil switching valve 11 to 15, and lubricates the clutch.
It passes through a check valve 5 for generating lubricating oil pressure and is connected to a tank 4.

Therefore, in the neutral case, the pressure oil discharged from the pump 3 contains the pressure generated by the spring 19 of the lubricating oil pressure generating check valve 5 or the pressure generated by the spring 21 of the lubricating oil switching valve.
The pilot pressure is so weak that it presses the piston 22 of the hydraulic clutch against the clutch plate 23, but does not cause the engine to start.

In addition, the return spring 20 of the hydraulic clutch
The return spring 21 of the lubricating oil switching valve is set to have such a strength that it is compressed by the pilot pressure and returns to its original position when the oil passage is directly connected to the tank 4 and the oil pressure is released.

The relief valve 16 has one end of the spool RS in contact with the compression coil springs 16a, 16b, and the other end facing the hydraulic chamber 16c.The relief valve 16 has an annular groove 16d on its outer peripheral surface and a throttle 16e extending from the groove 16d toward the spring 16a. The inside thereof is provided with an oil passage 16f that connects the groove 16d and the hydraulic chamber 16c.

The trimming plug TP has springs 16a and 16b.
is facing the spool RS. In the initial state (minimum oil pressure state) shown in Fig. 1, the large diameter spring 16
Although the small diameter spring 16b is in pressure contact with the end face of the plug TP, the small diameter spring 16b is separated from the plug TP. Hole 1
6g includes an annular stepped portion 16h on the inner peripheral surface portion away from the plug TP. The inner edge of the stepped portion 16h is
It protrudes radially inward from the opening edge of the case 16i to form a stopper for the plug TP. The hole 16g has another annular step 16j on the inner peripheral surface near the spool RS, and the step 16j and the plug are connected to each other.
A compression coil spring 16k (return spring) is compressed between the TPs. The end face of the plug TP opposite to the springs 16a and 16b is the hydraulic chamber 16l.
(trimming chamber), and the hydraulic chamber 16l is connected to the quick return valve 17 via an oil passage 16m.

A pump hydraulic chamber 17a and a tank oil passage 17b are formed on both sides of the spool HS of the quick return valve 17. Spool HS tank oil path 17b
The side end has a small diameter and an annular hydraulic chamber 17c is formed around it, and the oil passage 16m is connected to the hydraulic chamber 1.
Connected to 7c. Spool HS has both hydraulic chambers 1
It is provided with an aperture 17d that connects 7a and 17c.
A portion of the case 17e between the hydraulic chamber 17c and the oil passage 17b forms an annular valve seat 17f, and in the initial state shown in FIG. 1, the spool HS is seated on the valve seat 17f.

In the speed switching valve 2, the spool of the switching valve 2
The VS fits into the spool hole 41 of the spool housing 40 so as to be able to slide in the longitudinal direction, and an operating lever (not shown) is attached to the end 42 protruding from the hole 41.
are concatenated. The spool VS includes four land portions 43 to 46 sandwiching small diameter portions 47 to 49 in order from the end 42 side, and three land portions 43 to 46 sandwiching small diameter portions 47 to 49 at the end opposite to the end 42 into which the detent balls 53 fit. Annular grooves 50, 51, and 52 are provided in this order from the end portion 42 side.

54 is a ball biasing spring. The following ports are arranged on the outer periphery of the switching valve spool VS. That is, the low pressure port L connected to the oil passage _P1 , the port P connected to the pump oil passage _P2 , the port connected to the pilot oil passage 12' of the 2nd speed clutch 7' and the 2nd speed clutch lubricating oil switching valve, and the tank oil passage.
Port TP connected to P ₃ , 3rd speed clutch oil passage 8' and pilot oil passage 1 of 3rd speed clutch lubricating oil switching valve
3', port P' connected to pump oil path _P4 , port connected to 1st speed clutch oil path 6' and pilot oil path 11' of 1st speed clutch lubricating oil switching valve, port connected to tank oil path _P5. TP′ are arranged in order from the left.

When the forward/reverse switching valve 1 is in the neutral state, as described above, the pressure oil discharged from the pump 3 passes through the forward/reverse switching valve 1 and the lubricating oil switching valves 11-15, and lubricates each hydraulic clutch 7-10. It also passes through a pilot check valve 5 and is connected to the tank 4, and the hydraulic clutch selected by the speed switching valve 2 is controlled by the pilot pressure generated by the spring 19 of the pilot check valve 5 and the spring 21 of the lubricating oil switching valve. the piston 22 of the clutch plate 23
It is pressed so weakly that it does not start driving.
That is, when the forward/reverse switching valve 1 is in neutral and the speed switching valve 2 is in 1st gear, as shown in FIGS. 1 and 3, the oil passage 6' of the 1st gear clutch and the 1st gear lubricating oil switching valve The port communicating with the pilot oil passage 11' of No. 11 is connected to the port P', and the first speed clutch 6
The piston 22 is weakly pressed against the clutch plate 23. Similarly, when the speed switching valve 2 is in the 2nd speed, the port and the port P are connected and the piston 22 of the 2nd speed clutch 7 is connected, as shown in FIG.
is weakly pressed against the clutch plate 23 by pilot pressure. When the speed switching valve 2 is in the 3rd speed, as shown in Fig. 5, the port and port
When P' is connected, the piston 22 of the third speed clutch 8 is
It is weakly pressed against the clutch plate 23 by pilot pressure.

In addition, when the speed switching valve 2 is in the 1st speed, the ports connected to the clutch oil passages of the 2nd and 3rd gears and the pilot oil passage of the lubricating oil switching valve are connected to the port TP and connected to the oil passage _P3 . and is connected directly to tank 4. Therefore, the return springs 20 of the second and third speed hydraulic clutches 7 and 8 and the return spring 21 of the lubricating oil switching valve are in a restored state. Similarly, when the speed selector valve 2 is in 2nd speed, the port is port T' and the port is port T, that is, the port and the port are tank 4.
When the speed selector valve 2 is in the 3rd speed, the port is connected to port T', the port is connected to port T, that is, the port and the port are both connected to tank 4, and the return spring of the hydraulic clutch and lubricating oil are connected as before. The return spring of the switching valve returns to its original state.

In addition, as shown in FIG. 1, when the clutch is continuously switched, the trimming chamber 16l of the relief valve 16 is
All the pressure oil in the pump oil passage that is in the middle of switching is communicated with the tank so that the pressure oil can be quickly discharged from the check valve 17, which is a quick return valve, to the tank 4.

As shown in Fig. 3, when the speed clutch is switched from 1st speed to 2nd speed, ports P' and ports and ports T are cut off when lands 44 and 45 have moved a distance l ₂ ; Land 45 and land 43 are set at a distance l ₁ to connect port P and port and port and port T' more quickly.
Moving. Communication from the port to port T remains open.

Therefore, in the 1st gear state, pressure oil enters the hydraulic clutch 6 for starting, and later the relief valve 16 causes the pressure oil to rise and reach the set pressure.
During the switching operation to the second speed, that is, while the switching valve spool VS moves from the distance _l1 to the distance _l2 , each part operates as follows.

Until the switching valve spool VS moves from the distance l ₁ to the distance l ₂ , it is connected to the port and port T', and the first
The oil pressure of the first speed clutch oil passage 6' and the oil passage _P4 shown in the figure are released, and the first speed clutch 6 is cut off. At the same time, port P and port are connected to port T, and the hydraulic pressure in pump oil path _P2 is released.
The hydraulic pressure in the hydraulic chamber 16c of the relief valve 16 is also released, and the spool RS returns to its initial position under the repulsive force of the springs 16a and 16b. The hydraulic pressure in the hydraulic chamber 17a of the quick return valve 17 is also released, but in the state immediately after switching, the spool HS is seated on the valve seat 17f, and the hydraulic chambers 16l and 17c are
Since it communicates only with 17a via 7d, the pressure in the hydraulic chamber 17c is higher than that in the hydraulic chamber 17a. Therefore, the spool HS is connected to the hydraulic chamber 17.
It is pushed away from the valve seat 17 by the hydraulic pressure in c.

Then, the hydraulic chambers 16l, 17c and the passage 1
6m communicates with the oil passage 17b through a wide gap between the spool HS and the valve seat 17f, so the hydraulic chamber 16
The hydraulic pressure of 1 is released, and the plug TP is also returned to its initial position by being pushed by the springs 16k and 16a. Next, port P' and port T' are shut off, tank oil path _P5 is shut off from hydraulic pump 3, and port and port T are shut off, pressure oil in second-speed clutch 7 rises, and clutch engagement is performed. be exposed.

In addition, as shown in the lower part of FIG. 4, when switching the speed clutch 4 from 2nd speed to 3rd speed, the land 46 and the land 45 are separated by a distance l ₂ to disconnect the port P and the port and the port and the port T. However, the lands 44 and 45 are moved by a distance l ₁ earlier so as to connect the port P' and the port and the ports and the ports T. ports and ports
T′ remains linked. Therefore, the second speed clutch 7 reaches the set pressure of the relief valve 16 in the second speed state during the switching operation to the third speed, that is, before the switching valve spool VS moves a distance l ₂ , the quick return valve 17 reaches the set pressure. The pressure oil in the port drops to the tank from port T, and after moving a distance l ₂ , the pressure oil from port P' enters the port and rises due to the relief valve 16, and the speed clutch switches to 3rd speed. Ru.

Also, as shown in Figure 5, the speed clutch is set to 3.
When switching from speed to second speed, lands 44 and lands 45 move a distance l ₂ so as to cut off communication between port P' and port and between port and port T, but ports P and port and port and port Land 46 and land 45 move a distance l ₁ to connect T. ports and ports
T′ remains connected. Therefore, the third speed clutch 8 reaches the set pressure of the relief valve 16 in the third speed state during the switching operation to the second speed, that is, until the switching valve spool VS moves from the distance l ₁ to the distance l ₂ . The quick return valve 17 immediately lowers the pressure, and the pressure oil in the port is discharged to tank 4, and the distance
After _l2 movement, the pressure oil from port P enters the port and is raised by the relief valve 16, and the speed clutch is switched to 2nd speed.

Furthermore, as shown in the upper part of FIG. 4, when switching the speed clutch from 2nd speed to 1st speed, the lands 45 and 43 are separated by a distance so as to cut off communication between port P and port and communication between port and port T'.
l ₂ , but sooner the lands 44 and 45 are moved a distance l ₁ so as to connect port P' and port and port and port T. The port and port T remain in communication.

Therefore, the second speed clutch 7 reaches the set pressure of the relief valve 16 in the second speed state during the switching operation to the first speed, that is, until the switching valve spool VS moves from the distance l ₁ to the distance l ₂ . , quickly lowered by the quick return valve 17, the pressure oil in the port escapes to the tank 4, and after moving a distance l ₂ , the pressure oil from the port P' enters the port and releases the pressure oil into the relief valve 16.
The speed increases and the speed clutch switches to 1st gear.

FIG. 6 shows an example in which there is no lubricating oil switching valve, but when the forward/reverse switching valve 1 is switched from the neutral state to forward or reverse, pressure oil enters the hydraulic clutch 9 or 10 and is then activated by the relief valve 16. , the pressure oil rises and the vehicle starts moving. After starting, the hydraulic clutches 6, 7,
8, 9, and 10 are lubricated. Therefore, this embodiment is the same as the above embodiment except that the piston of the hydraulic clutch is moved by the pilot pressure and there is no effect of shortening the time lag, and the present invention can be applied to a speed switching valve.

As explained above, according to the present invention, one of the three clutches is connected to the pump independently and the other two are connected to the tank in the spool hole of the spool housing of the switching valve, and On the way, connect the ports of each oil passage so that the pump connects to the tank, from one end of the spool housing to the port that connects to the tank, the port that connects to the first clutch, the port that connects to the pump, the port that connects to the third clutch, and the port that connects to the tank. Because the ports are arranged as follows: a connecting port, a port connecting to the second clutch, and a port connecting to the pump, there is no need to create a hollow hole in the spool, and the ports also serve as ports T and ports P'. The number of ports can be reduced, the spool diameter can be made thinner, and the overall length can be shortened compared to conventional valves.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the hydraulic system of the embodiment of the present invention;
The figure is a sectional view of the hydraulic clutch, and Figures 3 to 5 are
FIG. 6, which is a sectional view of the speed switching valve spool, is a hydraulic system diagram of another embodiment. 1... Forward/forward switching valve, 2... Speed switching valve, 3...
...Pump, 4...Tank, 6,7,8...Hydraulic clutch, 40...Spool housing, 41...
Spool hole, P...port, VS...valve spool.

Claims (1)

[Scope of utility model registration request] The spool hole 41 of the spool housing 40 of the switching valve 2 is sequentially connected to a port T' connected to the tank 4, a port I connected to the first clutch 6, a port P' connected to the pump 3, a port connected to the third clutch 8, and the tank 4. A port T connected to the second clutch 7, a port P connected to the pump 3 are provided, and one of the plurality of clutches 6, 7, 8 is independently pumped to the spool VS provided in the spool hole 41. 3 and the other two are connected to the tank 4, and in the middle of switching the switching valve, the lands 43, 44, 45, 46 and the small diameter parts 47, 48, so that the pump 3 is connected to the tank 4. 49. A switching valve device for a hydraulic clutch, characterized in that: