JPH048651B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a system in which the biasing force of a spring is increased by the action of secondary pilot pressure at a midway point in an oil passage that supplies pressure oil to a friction type hydraulic clutch. A friction type consisting of a bypass valve that opens against the pressure, a low-pass valve that closes against the urging force of a spring due to the action of the secondary pilot pressure, and an orifice installed in parallel. This invention relates to a pressure control valve mechanism for a hydraulic clutch.

[Prior Art] According to the pressure control valve mechanism of the friction type hydraulic clutch described above, the secondary side pilot pressure that closes the low-pass valve is low enough to move the piston installed in the hydraulic clutch into contact with the friction plate. Adjust and set the biasing force of the spring so that the pressure is
The secondary side pilot pressure that opens the high-pass valve is set to a pressure that does not cause a shock to the hydraulic clutch even if the friction transmission output rapidly increases, and the biasing force of the spring is adjusted to set the clutch to engage. When the supply of pressure oil is started, the pressure of the pressure oil flowing from the low-pass valve rapidly rises to the pressure at which the piston starts pressing the friction plate, shortening the piston operation time, and closing the low-pass valve. After that, while maintaining the half-clutch state according to the load, the oil pressure gradually increases due to the pressure oil flowing from the orifice, and the transmission output also gradually increases. When the pressure rises to the predetermined pilot pressure, the high-pass valve opens. The hydraulic pressure increases rapidly and the clutch is reliably engaged, which reduces the impact on the hydraulic clutch and allows the hydraulic clutch to operate smoothly. The required minimum pressure varies depending on the size of the load, and in order to shorten the time it takes for the hydraulic clutch to start operating and ensure smooth operation of the hydraulic clutch, the high-pass valve should be opened depending on the size of the load. It is necessary to change the pilot pressure to close the low-pass valve and the pilot pressure to close the low-pass valve.

The adjustment operation for changing the biasing force of the spring for changing the pilot pressure has been performed separately for each of the high-pass valve and the low-pass valve.

[Problem that the invention seeks to solve]

For this reason, when the amount of adjustment operation for the high-pass valve is too small or too large compared to the amount of adjustment operation for the low-pass valve, the time that can be maintained in the half-clutch state is too short, causing a shock to the hydraulic clutch, or conversely, the half-clutch state There is a problem in that it takes too long to maintain this state and it takes time for the hydraulic clutch to operate, making it impossible to perform proper adjustment quickly.

The present invention solves the problems of the above-mentioned prior art,
This problem was solved by focusing on the fact that there is a certain correlation between the amount of adjustment operation for the high-pass valve and the amount of adjustment operation for the low-pass valve in order to optimize the operation of the hydraulic clutch, so that quick adjustment operations can be performed. The purpose is to

[Means for solving problems]

The characteristic configuration of the present invention for achieving the above object is that, in the pressure control valve mechanism of the friction type hydraulic clutch described above, the biasing force of one of the two springs is changed in conjunction with the change in the biasing force of the other spring. A biasing force changing mechanism for changing the biasing force of the spring at the same time is provided, and this configuration produces the following effects.

[Effect]

The other valve is operated by an amount corresponding to the amount of operation of one valve, and the pilot pressure for opening the high-pass valve and the pilot pressure for closing the low-pass valve are adjusted at a constant ratio.

〔Effect of the invention〕

The pilot pressure for opening the high-pass valve and the pilot pressure for closing the low-pass valve can be quickly and appropriately adjusted depending on the magnitude of the load.

〔Example〕

Fig. 7 shows the electric structure of the transmission case M installed on the tractor, which has a synchronized mesh main gear that can freely switch between four stages, spanning the input shaft 1 interlocked with the engine E and the first transmission shaft 2 for traveling. Gearbox H ₁
A synchronized mesh type forward/reverse gear transmission device in which a friction plate type hydraulic clutch C is provided between the first transmission shaft 2 and the second transmission shaft 3 for traveling, and the output of the second transmission shaft 3 is changed between forward and reverse directions. H ₂ , a synchromesh type first auxiliary gear transmission H ₃ that can freely switch the output therefrom between two high and low stages, and a second auxiliary gear transmission H ₄ that can freely switch the output therefrom between two high and low stages. The output of the second auxiliary gear transmission _H4 is transmitted to the differential mechanism 4A for the rear wheels 4 and the operating mechanism 5 for the front wheels 5.
It is configured to transmit power to A.

A synchromesh type gear transmission 7 is provided which changes the power of the input shaft 1 into four stages and transmits it to the power output transmission shaft 6, and the transmission shaft 6 and the power output shaft 8
A relay transmission shaft 9 is provided between the power output shaft 8 and the power output shaft 8, so that the speed of the power take-off shaft 8 can be changed.

Next, the speed change operation structure for the traveling transmission system will be described in detail with reference to FIGS. 7 and 6.

That is, the main gear transmission H ₁ includes two main gear transmission shifters 10A, 1 that are alternatively operated.
Two operating hydraulic cylinders 11A and 11B are attached to each of which are interlockingly connected to each other, and an operating hydraulic cylinder ₁₃ which is interlockingly connected to a first auxiliary gear shifter 12 is attached to the first auxiliary gear transmission H3. It is attached.

Also, two operating hydraulic cylinders 11A, 11B for the main gear transmission _H1 and an operating hydraulic cylinder 1 for the first auxiliary gear transmission _H3 .
Three three-position switching valves S ₁ , S ₂ , and S ₃ are constructed in such a manner that the three pistons are also used as sliding spools.

The operating hydraulic cylinders 11A, 11B, 13
supply of hydraulic pressure to, and the three-position switching valve
Hydraulic pressure is supplied to S ₁ , S ₂ , and S ₃ by main control valve V ₁
Pressure oil is supplied to this 9-position switching valve _V1 from a _hydraulic pump P to a pressure reducing valve ₁ .
5.

The transmission hydraulic clutch C is driven by hydraulic pressure supplied from the pressure reducing valve 15 via the pressure control valve mechanism 16, and is driven by the hydraulic pressure supplied from the pressure reducing valve 15 through the pressure control valve mechanism 1.
6 and the hydraulic clutch C, there is an alternative between a clutch engaged state in which pressure oil from the pressure control valve mechanism 16 is supplied to the clutch C, and a clutch disengaged state in which the pressure oil in the clutch C is returned to the tank T. Four pilot pressure-operated two-position switching valves 17A, 17B, 17C, and 17D are connected in series as a switching valve 17 that can be freely switched to one pilot pressure-operated two-position switching valve. 17A is pressure oil supplied from the auxiliary control valve V2, which is operated in conjunction with the manual operation lever 18 that operates the forward/reverse gear transmission _H2 and is connected in parallel to _the main control valve _V1 . The remaining three pilot pressure-operated two-position switching valves 17B, 17C, and 17D are operated by
The main gear transmission H ₁ , _the forward/reverse gear transmission H ₂ , and _{the first} sub The four pilot pressure-operated two-position switching valves 17 are activated only when all of the gear transmissions _H3 are in the transmission state.
When all of A, 17B, 17C, and 17D are switched to a state where they are in communication, the state is switched to a clutch engaged state.
The clutch C is configured to be automatically switched in conjunction with a gear shift operation.

However, when one of the two hydraulic cylinders 11A, 11B of the main gear transmission _H1 is operated to the gear shifting side, the other hydraulic cylinder is operated and held in the neutral position by pressure oil. .
Further, the second auxiliary gear transmission _H4 is provided with a shifter that can be operated using a speed change lever. moreover,
The transmission device 7 relative to the power take-off shaft 8 is configured to be manually operated.

In the figure, N and F ₁ to F ₈ each indicate the operating position of the main control valve V ₁ , and F and R indicate the operating position of the auxiliary control valve V ₂ .

As shown in FIG. 1, the pressure control valve mechanism 16 is a secondary valve that operates to open a spool 19A as a piston by the action of pilot pressure on the secondary side leading to a hydraulic clutch C against the biasing force of a spring 19B. A side high-pass valve 19, a low-pass valve 20 that closes a spool 20A as a piston against the biasing force of a spring 20B under the action of pilot pressure, and an orifice 21 are assembled in the case 22 in a state where they are connected in parallel. The springs 19B and 20B are configured with a biasing force such that the pilot pressure for opening the high-pass valve 19 is higher than the pilot pressure for closing the low-pass valve 20.
The biasing force can be changed by a biasing force changing mechanism 23.

The biasing force changing mechanism 23 includes both springs 19
Rods 24 and 25 are elastically deformed by pressing B and 20B to change and adjust their biasing force.
It is attached so that it can slide freely in the axial direction while penetrating into the case 22, and contact bolts 24A and 25A are attached to the protruding ends of both rods 24 and 25 in an adjustable manner, and a cover 26 is provided to cover the protruding parts of the rods. Eccentric cams 28A and 28B are integrally fixed to a rotating shaft 27 attached to the case 22 and supported by this cover 26, and the lever 2 attached to the rotating shaft 27
9, the eccentric cams 28A, 28B engage both springs 19 via the contact bolts 24A, 25A.
By deforming B and 20B by the same amount, the biasing force can be changed and adjusted at the same time.

Therefore, when the spring constants of both springs 19B and 20B are the same, when the swing lever 29 is swung, the biasing forces of both springs 19B and 20B are changed by the same amount, and the line segment indicating the pressure control state is As shown in the figure, they move approximately in parallel.

Then, set the swinging position of the swinging lever 29 to the cover 2.
When the display plate 30 attached to position 6 is set to travel position A, the pressure control state is suitable for the lightest load, where only travel is performed, as shown in line segment A, and when it is set to light load position B, as shown in line segment B. The pressure control state is suitable for light loads such as shallow rotary tilling work, etc., and when adjusted to normal load position C, the pressure control state is suitable for medium loads such as normal tillage and plowing work as shown in line segment C. When the pressure is adjusted to heavy load position d, the pressure control state becomes suitable for heavy loads such as indexing work as shown in line segment d.

In addition, in the above embodiment, the eccentric cams 28A, 2
By relatively changing the reference phase of spring 8B, the biasing force of both springs 19B and 20B can be adjusted at different ratios.

[Another example]

FIG. 4 shows another embodiment of the present invention, in which the biasing force changing mechanism 23 is mounted on both protruding ends of rods 24A and 24B that change and adjust the biasing forces of the springs 19B and 20B, and a swinging member is pivotally supported on the case 22. At the same time, the free end side of the swinging member 31 is fitted with a stud bolt fixed to the case 22, and the biasing force of the spring 34 fitted onto the bolt 33 is applied. The swinging member 31 is configured to be fixed in a swinging manner by tightening the wing nut 35 against the above-mentioned pressure. The distance Ll to the contact position on the low-pass valve 20 side is larger than the distance Ll to the contact position on the low-pass valve 20 side, and when the swinging member 31 is swung by a certain amount, the amount of displacement with respect to the spring 20B on the low-pass valve 20 side is the same as that of the spring 19B on the high-pass valve 19 side. The ratio of the distances Lh and Ll is set to be smaller than the amount of displacement relative to the distance.

Therefore, when the spring constants of both springs 19B and 20B are the same, the spring 20B on the low-pass valve 20 side when the swinging member 31 swings a certain amount
The amount of change in the biasing force for the high-pass valve 19
The amount of change in the biasing force for the side spring 19B
As shown in Fig. 5, when the pilot pressure for opening the high-pass valve 19 is adjusted to a high value, the pressure rise and hold property b rises more rapidly than a before the adjustment.
is obtained.

[Brief explanation of drawings]

The drawings show an embodiment of a pressure control valve mechanism for a friction type hydraulic clutch according to the present invention, and FIG. 1 is a longitudinal sectional view;
Fig. 2 is a side view of the urging force changing mechanism, Fig. 3 is a pressure control characteristic diagram, Fig. 4 is a vertical sectional view of another embodiment, and Fig. 5 is a pressure control characteristic diagram of another embodiment. FIG. 6 is a hydraulic system diagram for the friction type hydraulic clutch, and FIG. 7 is a schematic diagram showing the transmission structure of the tractor. C...Friction type hydraulic clutch, 19...High pass valve, 20...Low pass valve, 19B, 20
B... Spring, 21... Orifice, 23...
...Biasing force changing mechanism.

Claims (1)

[Claims] 1. A high-pass valve 19 that opens against the biasing force of a spring 19B by the action of the secondary pilot pressure is installed in the middle of the oil passage that supplies pressure oil to the friction type hydraulic clutch C; In a pressure control valve mechanism for a friction type hydraulic clutch, which is constructed by interposing a low-pass valve 20 that closes against the biasing force of a spring 20B by the action of pressure and an orifice 21 in parallel, both of the above-mentioned A friction type hydraulic clutch characterized in that it is provided with a biasing force changing mechanism 23 that simultaneously changes the biasing force of one of the springs 19B and 20B in conjunction with changing the biasing force of the other spring 20B. Pressure control valve mechanism.