JPS6323637Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to a speed change control device for a transmission that is changed by turning on and off a plurality of hydraulically operated clutches. Conventionally, in a vehicle equipped with this type of transmission, when fine running (fine starting and immediate stopping) is performed by turning on and off the power transmission of the transmission, a brake provided separately from the transmission is required in addition to the transmission because of problems with the vehicle body inertia and external load. This causes a problem that fine running operation of the vehicle becomes troublesome. This invention has been made in consideration of the above circumstances, and its object is to provide a speed change control device for a transmission that can provide a brake function to the transmission itself and can easily perform fine running. An embodiment of the invention will be described below with reference to the drawings. In FIG. 1, the output of an engine 1 is transmitted to a pair of left and right sprockets 7, 7 via a damper 2, a transmission 3, a horizontal shaft 4, a pair of left and right steering clutches and brakes 5, 5, and a final reduction gear 6, 6. The transmission 3 is equipped with forward and reverse planetary gear mechanisms ₈₁ , ₈₂ provided on the input shaft 3a side, first and second speed planetary gear mechanisms ₈₃ , ₈₄ provided on the output shaft 3b side, and hydraulically operated clutches 9R, 9F, 9, 9, 9 for reverse, forward, first, second and third speeds, and changes gears as shown in the following table.

[Table] Each of the hydraulic clutches 9 is turned OFF by spring force.
The structure is such that it turns on when pressure oil is supplied to the pressure receiving chamber 9', and the supply of pressure oil is controlled by the control circuit shown in FIG. In other words, the pump 1 driven by the engine 1
0 discharge passage 11 is a modulating valve 1
The inlet port 1 of the speed valve 15 is
6 is connected. The speed valve 15 blocks the inlet port 16 and closes the first, second, third, fourth ports 17, 18, 19,
20 to the drain port 21, the inlet port 16 and the first and fourth ports 17, 2
0 is in communication and the second and third ports 18 and 19 are connected to the drain port 21, the inlet port 16 is in communication with the second and fourth ports 18 and 20, and the first and third ports 17 and 19 are connected. and drain port 21
and a third speed position, which communicates the inlet port 16 with the third and fourth ports 19 and 20 and communicates the first and second ports 17 and 18 with the drain port 21. Said first, second and third ports 17, 18, 19
Hydraulic actuated clutch 9 for 1st speed, 2nd speed, and 3rd speed
. 25 is provided, and the fourth port 20 is connected to an inlet port 28 of a directional valve 27 via a fourth line 26, which is provided with an inching valve 29. The directional valve 27 has a forward position F where the inlet port 28 is connected to the pressure receiving chamber 9'F of the forward hydraulically actuated clutch 9F, and a reverse position R where the inlet port 28 is connected to the pressure receiving chamber 9'R of the reverse hydraulically actuated clutch 9R. It is equipped with On the other hand, the brake valve 25 has a first position (a) that connects the third pipe line 24 to the pressure receiving chamber 9' and a second position (b) that connects the pressure receiving chamber 9' to the brake oil passage 30. is the discharge path 1
It is connected to the inflow side of the quick return valve 13 in 1. In addition, the inching valve 29 is operated by operating the pedal 31 to move the spring receiver 32, thereby adjusting the pressure regulating spring 3.
When the set load in step 3 is reduced, the pressure on the outlet side gradually decreases, resulting in a pressure reducing valve structure, and the pedal 31 is interlocked with the brake valve 25, and when operated with a predetermined stroke, the brake valve 25 is set to the second position B. , the brake valve 25 and the inching valve 29 are integrated. In other words, as shown in FIG. 3, the brake valve 25
The outlet port 40 connected to the pressure receiving chamber 9 _' , the third pipe line 24, and the brake oil line 30 are connected to the one side valve hole B1 partitioned by the partition wall C in the valve hole B drilled in the valve box A. connected first and second inlet ports 41,
A spool 43 that is disconnected from the spool 42 is slidably inserted, and a rod 46 that moves the spring receiver 45 of the pressure regulating spring 44 is inserted into the spool 43 and the other side valve hole through the partition wall C.
B ₂ protrudes outward from the valve box A, and the spool 4
A load piston 47 that contacts the partition wall C is fitted into the blind hole 43a on the other side of 3 to form a back pressure chamber 48, and the back pressure chamber 48 is opened to the outlet port 40 through a small hole 48'. A spring 49 is provided between C and the spool 43 to maintain the spool 43 at the first position A where the outlet port 40 and the first inlet port 41 are communicated with each other at all times. The inching valve 29 has an inlet port 5 connected to the fourth pipe line 26 at the other side valve hole _B2 of the valve box A.
A spool 52 is provided to be slidable and fit into the rod body 46, and a load piston 53 that contacts the partition wall C is inserted into a blind hole 52a on one side of the spool 52 to create a back pressure. forming a chamber 54;
The back pressure chamber 54 is opened and communicated with the outlet port 51 through the pore 54', and the spool 52 is slid by the pressure of the back pressure chamber 54 and the pressure regulating spring 33 to disconnect the inlet port 50 and the outlet port 51. In addition to this,
The spring receiver 32 of the pressure regulating spring 33 is loosely fitted into the rod 46 and abuts the protrusion 46a, and the rod 46 is connected to the pedal 31 via a link mechanism 56, and the pedal 31 is shown as a spring 57. The brake valve 25 and the inching valve 29 are held in the illustrated positions. When the pedal 31 is depressed, the rod 46 is moved to the left, the spring receiver 32 is also moved to the left, the spring load of the pressure regulating spring 33 is reduced, and the spool 52 is moved to the back pressure chamber 5.
4, the pressure oil in the outlet port 51 is moved in the direction of blocking the inlet port 50 and the outlet port 51.
P ₁ is reduced in pressure according to the stroke of the pedal 31 as shown in Figure 4 A, and the spring receiver 45 is also moved to the left, the spring force of the pressure regulating spring 44 is increased, and the spool 43 is moved to the left. Although the wrap length is long, the inlet port 42 and the outlet port 40 are moved.
It doesn't communicate with. When the pedal is depressed beyond a predetermined stroke, the pressure at the outlet port 51 is further reduced, and the pressure regulating spring 43 is further pushed.
and the outlet port 42 are sequentially opened and communicated with the pressure receiving chamber 9'.
The pressure P ₂ gradually increases as shown by B in the fourth diagram. Then, when the pedal 31 is further depressed, the spring receiver 3
2 comes into contact with the stopper portion 32', and the pressure in the outlet port 51 is maintained at the current pressure until the end of the stroke (this pressure is higher than the pressure corresponding to the return spring of the hydraulic actuating clutch 9), and the brake valve 25 is pressed against the spool 43. is bulkhead C (i.e. stopper)
A predetermined brake pressure is supplied from the second inlet port 42 to the outlet port 40 to the pressure receiving chamber 9'. Therefore, the speed valve 15 is set to the 1st speed position, and the direction valve 2 is set to the 1st speed position.
7 to the forward position F, turn on the forward and 1st gear hydraulic actuating clutches 9F, 9, and from the state of 1st forward gear, depress the pedal 31 to operate the inching valve 29 and release the pressure oil in the pressure receiving chamber 9'F. becomes low pressure and the forward hydraulic actuation clutch 9F turns OFF. For this reason, the transmission 3 becomes neutral and does not transmit power. Then, when the pedal 31 is returned to its original position and the inching valve 29 is set to the non-operating position, the pressure oil in the pressure receiving chamber 9'F becomes high pressure and the forward hydraulic actuating clutch 9F is activated.
It turns on, and the transmission 3 becomes the first forward gear. In this way, by operating the pedal 31, the power transmission of the transmission 3 can be turned on and off, and the vehicle can be moved slightly. Further, when the pedal 31 is depressed for a certain stroke or more, the brake valve 25 becomes the second position B, pump discharge pressure oil is supplied to the pressure receiving chamber 9', and the third-speed hydraulically operated clutch 9 is turned on. At this time, since the first gear hydraulic clutch 9 is ON, the output shaft 3b of the transmission 3 is in a braking state, and the vehicle is braked. In this way, the vehicle can be braked by the transmission without also using a separate brake, and the pedal 3
Just by pressing the button 1, the vehicle can be easily maneuvered. Furthermore, since the brake hydraulic circuit 30 is connected to the inflow side of the quick return valve 13 of the pump discharge path 11, when the brake valve 25 is operated regardless of the hydraulic pressure increasing device 14, the pressure oil discharged from the pump 10 immediately receives pressure. It is supplied to chamber 9' and has good response. In addition, in the state of forward/reverse 3rd gear, the pressure receiving chamber 9'
Since pressure oil is supplied to the back pressure chamber 48 and the brake valve 25 is held in the first position A by the pressure oil in the back pressure chamber 48, the brake valve 25 does not go to the second position B even if the pedal 31 is depressed. There is no problem because there is no fine running operation at the highest speed. In addition, the outlet port 51 of the inching valve 29
The pressure of the hydraulically operated clutch 9 is designed not to drop below the pressure corresponding to the return spring force of the hydraulically operated clutch during operation until the end of the stroke.
This means that the pressure receiving chamber 9' is filled with pressure oil, and when the pedal 31 is placed in the non-operating position again, the oil pressure increases immediately without requiring time for the pressure receiving chamber 9' to be filled with pressure oil. There is no response delay, and no peak oil pressure occurs and the shock becomes large. Note that if the pressure receiving chamber 9' is filled with pressure oil when the inching valve 29 is operated to the end of the stroke, the transmission will not be in a completely neutral state and will attempt to run slightly, but the brake valve 25 will not reach the second position. Since the transmission is switched to , the transmission is braked and the vehicle does not skid. In the above embodiment, the brake circuit 30 is connected to the pressure receiving chamber 9' of the third-speed hydraulically actuated clutch 9 via the brake valve 25, but the invention is not limited to this, and the transmission output shaft 3b may be in a braking state. The brake circuit 30 may be connected to the pressure receiving chamber 9' of any hydraulically operated clutch 9 via the brake valve 25. The present invention is as described above, and the rod 46 is moved by the operating member to bring the brake valve 25 to the pressure oil supply position, thereby supplying the discharge pressure oil of the pump to one predetermined hydraulic clutch for shifting. Transmission 3
Since the output shaft 3b of the transmission can be braked, the transmission itself can have a braking function. Further, the brake valve 25 and the spring receiver 32 of the inching valve 29 are connected by a rod 46, and while the spring receiver 32 moves to a position where the pressure on the outlet side of the inching valve 25 decreases to a predetermined pressure, the brake valve 25 is closed. Since the pressure oil supply position is not reached, by operating the operating member over a predetermined stroke, the forward/reverse hydraulic clutch can be turned OFF and the transmission can be placed in neutral, and when the operating member is operated over the above-mentioned predetermined stroke, the brake valve 25 will be in the pressure oil supply position. At the supply position, the output shaft 3b of the transmission can be braked. Therefore, by operating a single operating member, it is possible to make small movements or brake, which makes the operation easy, but also reduces the need for heavy operating force during operation.
The operation timings of the inching valve 29 and the brake valve 25 do not change or change, and the inching valve 29 and the brake valve 25 can be surely operated with the same operation timing with a light operating force.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention.
2 is a schematic overall view, FIG. 2 is a hydraulic circuit diagram, FIG. 3 is a sectional view showing a specific example of a brake valve and an inching valve, and FIG. 4 is a hydraulic characteristic table. 3 is a transmission, 9 is a hydraulically operated clutch, 9' is a pressure receiving chamber, 10 is a pump, 15 is a speed valve, 25 is a brake valve, 27 is a directional valve, 29 is an inching valve, 31 is an operating member (pedal), 46 is a rod.

Claims (1)

[Scope of utility model registration request] A forward rotation hydraulic actuation clutch 9R, a reverse rotation hydraulic actuation clutch 9F, which selectively couple with or dissociate from the input shaft 3a to rotate the output shaft 3b in forward and reverse directions, and the output shaft 3.
In a transmission equipped with a plurality of shift hydraulically actuated clutches 9, 9, 9 that selectively couple to or dissociate from the output shaft 3b to increase, decrease, or neutralize the forward/reverse rotational speed of the output shaft 3b, the plurality of shift hydraulically actuated clutches A speed change valve 15 selectively supplies the discharge pressure oil of the pump 10 to any one of the clutches 9, 9, 9, and selects the discharge pressure oil of the pump 10 to either one of the forward/reverse hydraulic operating clutches 9R, 9F. a directional valve 27 for supplying
an inching valve 29 which is provided between the inching valve 29 and the discharge side of the inching valve 29 and which sequentially lowers the outlet side pressure by moving the spring receiver 32 to reduce the set load of the pressure regulating spring 33; and the plurality of hydraulically operated clutches 9, 9 for shifting. ,9
A brake valve 25 for supplying the discharge pressure oil of the pump 10 is provided to a predetermined one of the inching valves 29 and 29.
The spring receiver 32 of the inching valve 2 is connected to the rod 46.
When the spring receiver 32 moves further than the position where the pressure on the outlet side of the brake valve 9 decreases to a predetermined pressure, the brake valve 25
A gear change control device for a transmission, characterized in that the rod 46 is connected to be switched to a pressure oil supply position, and the rod 46 is connected to an operating member.