JPS63318352A - Pressure adjusting mechanism for hydraulic clutch - Google Patents

Abstract

PURPOSE:To obtain the initial raised pressure characteristic corresponding to the speed change state by installing a selector valve for connecting a pump pressure to a low-pass valve having a high pilot pressure, as the traveling speed change position permits high speed. CONSTITUTION:A hydraulic circuit connected with a pump P is connected with a three-position selector valves S1, S2, and S3 which operate the oil passage of a main control valve V1 by the hydraulic cylinders 11A, B, and 13 through a reducing valved 15 and further connected with selector valve 17 which ON/ OFF-controls a clutch C. Further, the hydraulic pressure of the reducing valve 15 is connected with the three-position selector valve 22 and an auxiliary control valve V2 operated by a pressure adjusting mechanism 16 and a manually operated lever 18. The pressure adjusting mechanism 16 is constituted of the high/low low-pass valves 20A and B, high pass valve 19, and an orifice 21, and the three- position selector valve 22 is supplied with the pressurized oil into the low pass valve 20A and B side in the high or low speed state. Therefore, the initial raised pressure characteristic corresponding to the speed change state can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a pressure regulating mechanism for a hydraulic clutch that provides a pressure regulating mechanism in a pressure oil supply path to a hydraulic clutch for shifting, thereby reducing switching shock during gear shifting. .

[Conventional technology]

Conventionally, a pressure adjustment mechanism consists of a low-pass valve mechanism that is closed by pilot pressure on the secondary side, a high-pass valve that is opened by pilot pressure on the secondary side, and a throttle mechanism that is connected in parallel to these valves. It had a constant pressure increase characteristic regardless of the gear shift position (Japanese Patent Application Laid-Open No. 1983)
1-6028).

[Problem that the invention seeks to solve]

In this case, if the closing operation pilot pressure of the low-pass valve mechanism is set high, the hydraulic clutch will become dark at a pressure higher than the initial engagement pressure (meet point) of the hydraulic clutch required in low-speed shifting conditions, resulting in a large shift shock. On the other hand, if the pilot pressure is set low, the hydraulic clutch will engage at a pressure lower than the initial engagement pressure (meet point) of the hydraulic clutch required in a high-speed shift state, so the required initial 1V pressure will be reduced. There is a problem that it takes a long time to reach the desired position, and it is difficult to set the initial y, y+s++ pressure of the hydraulic clutch corresponding to the shift state.

SUMMARY OF THE INVENTION An object of the present invention is to provide a low-pass valve mechanism with a simple switching means that can provide initial pressure increase characteristics corresponding to the speed change state.

[Means for solving problems]

The characteristics of the present invention are as follows: - The low-pass valve mechanism is constructed by connecting multiple low-pass valves with different pilot pressures in parallel; The operation and effects are as follows.

[Operation] In other words, by connecting multiple low-pass valves in parallel and setting the pilot pressure of each low-pass valve to a different value, the initial joint pressure (meeting pressure) of the hydraulic clutch can be adjusted as shown in Figure 3. point) in a low speed state (P
It is possible to switch between 2) and high-speed conditions (P, ). In low-speed conditions, the hydraulic clutch is operated at low pressure (P2), and after that, the operating pressure is gradually increased with the throttle in the half-clutch condition. It adopts a long boost characteristic in a half-clutch state to transition to a complete clutch state, and conversely, in a high-speed state, the initial +1
JI adopts a boosting characteristic that shortens the boosting time compared to raising the joint pressure (p,) from low pressure (P2) to high pressure (Pl) in a half-clutch state.

〔Effect of the invention〕

This takes advantage of the fact that when driving at high speeds, the shaft torque is smaller and the inertia of the vehicle body can be used to shift gears, so there is less shift shock even when the hydraulic clutch is operated at high pressure. We were able to provide something useful.

However, it is also possible to provide an accumulator or the like instead of the low-pass valve to achieve the same effect.
Because of its structure, the low-pass valve can set the pressure increase time to the initial joint pressure (p or P2) in a shorter time, so it is more useful because there is less slippage on slopes, etc.

〔Example〕

Figure 2 shows the transmission structure inside the mission case (gate) installed on the tractor, and the transmission structure between the input shaft (1) interlocked with the engine (ε) and the first transmission shaft (2) for traveling is shown in Figure 2. A synchromesh type main gear transmission (Hl) that can freely change gears is provided, a friction plate type hydraulic clutch (C) is provided between the first transmission shaft (2) and the second driving transmission shaft (3), A synchromesh type forward/reverse gear transmission (H2) that changes the output of the second transmission shaft (3) in forward and reverse directions, and a synchromesh type first auxiliary gear transmission (H2) that can freely switch the output from the second transmission shaft (3) into two high and low stages.
111), and a second auxiliary gear transmission (H4) that can freely switch the output from the second gear transmission into two high and low stages, and
The output of the second auxiliary gear transmission (H4) is configured to be transmitted to the differential mechanism (4A) for the rear wheels (4) and the differential mechanism (5A) for the front wheels (5).

A synchromesh type gear transmission device (1) that changes the power of the input shaft (1) in four stages and transmits it to the power output transmission shaft (6).
7), as well as a transmission shaft (6) and a power take-off shaft (8).
A relay transmission shaft (9) is provided between the power output shaft (8) and the power output shaft (8).

Next, the speed change operation structure for the driving transmission system will be described in detail with reference to FIGS. 1 and 2.

That is, the main gear transmission (Il+) has two alternatively actuated main gear shifters (IOA).

(IOB), and two operating hydraulic cylinders (11A) and (11B) are attached, each of which is interlocked with the other.
The first auxiliary gear transmission (l) is attached with an operating hydraulic cylinder (13) to which a first auxiliary gear shifter (12) is interlocked and connected.

Further, two operating hydraulic cylinders (11^), (IIB) for the main gear transmission (H1) and an operating hydraulic cylinder (113) for the first auxiliary gear transmission (113) are provided.
13) Three 3-position switching valves (Sl) and (Sz) are installed in a state where the piston of 13) is used as a rotating spool for dual use.

(S3) is configured.

The operating hydraulic cylinder (11^) + (IIB),
The supply of pressure oil to (13) and the three-position switching valves (sl), (sz), and (S3) are performed using a Rochley type nine-position ( N, F, ~F, ) switching valves are operated, and pressure oil is supplied to this 9-position switching valve (Vl) from a hydraulic pump (P) via a pressure reducing valve (15).

The transmission hydraulic clutch (C) is driven by the hydraulic pressure supplied from the pressure reducing valve (15) via the pressure adjustment 1ffiFfis (16), so the pressure adjustment mechanism (16) and the hydraulic clutch (4) C), a clutch engaged state in which pressure oil from the pressure horn 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) as switching valves (17) which can be selectively switched between.

(17B), (17c), and (170) are connected in series, and one of these, a pilot pressure operated two-position switching valve (17A), controls the forward/reverse gear transmission (I+□). The remaining three The pilot pressure operated two-position switching valves (17B), (17C), and (17D) are the three-position switching valves (Sl), (S2), and (S3), respectively.
) is operated by pressure oil supplied from the main gear transmission (n + ), forward gear transmission (11□
), and the first auxiliary gear transmission (H3) are all in the transmission state, the four pilot pressure operated two-position switching valves (178), (17B), (17C),
When all of (170) are switched to the communicating state, the clutch (C) is switched to the clutch engaged state, and the clutch (C) is automatically switched in accordance with the speed change simulation.

However, when one of the two hydraulic cylinders (IIA) and (IIB) of the main gear transmission ff (II,) is operated to the shifting side, the other hydraulic cylinder is operated and held in the neutral position by pressure oil. It is structured as follows. Also, the second
The auxiliary gear transmission (u,) is equipped with a shifter that can be operated using a gear shift lever.

Furthermore, the transmission device (7) relative to the power take-off shaft (8) is configured to be manually operated.

In addition, in the figure, each of (N) and (Fl) to (F3) is
The operation position of the main control valve (Vl) is shown, and (F) and (
R) indicates the operating position of the auxiliary control valve (v2), and (H)
and (L) is the 3-position switching valve (S3) for the first auxiliary gear transmission.
) indicates the operating position.

As shown in FIGS. 1 and 2, the pressure adjustment mechanism (1
6) is the pilot pressure on the secondary side (first 31 of the hydraulic clutch).
11 joint pressure) (F,) is high pressure (e.g. 4.5 kg/cn
H side port-pass valve (20A) which is closed by the pilot pressure in l) and the pilot pressure on the secondary side (P2)
is a low pressure (e.g. 2 kg/cnl) inlet-pass valve (20B) and a pilot pressure (PO) on the secondary side.
It consists of a high-pass valve (19) that opens at a pressure of 16.5 kg/cnl (for example, 16.5 kg/cnl), and an orifice (21) as a throttle mechanism connected in parallel to these valves. Further, on the upper side of the pressure oil path of the low-pass valve mechanism (20) consisting of the H-side port-pass valve (20A) and the L-side port-pass valve (20B), a three-position switching valve for the first sub-gear transmission device is provided. A 3-position switching valve (22) is provided which is interlocked and connected to the spool of (S3), and when the first auxiliary gear transmission (Hl) is in a high-speed state, the 3-position switching valve (22) is connected to the H side port. - Pressure oil is supplied to the pass valve (20^) side, and conversely, when the first auxiliary gear transmission (II: l) is in a low speed state, pressure oil is supplied to the L side port - pass valve (20B) side. It serves as a selection switching means.

As shown in Figure 4, with respect to the mission case (M), there is a first blazer (25) that only allows air to flow out of the mission case (M), and a first blazer that only allows air to flow into the mission case (M). 2nd Blazero (26) that allows
and. Then, place a rubber lid (
25^) and (268) are provided. In addition, as shown in Fig. 5, a front wheel speed increasing mechanism (27) that makes the rotational speed of the front wheels faster than the rotational speed of the rear wheels is installed inside the transmission case (M). Alternatively, a structure may be adopted in which the transmission case is provided within the transmission case where the transmission torque is small. The front wheel speed increasing mechanism (27) loosely fits a clutch case (29A) containing a multi-friction plate to the Hebel gear output shaft (28) to the rear-wheel differential mechanism (48), and a clutch case (29A) containing a multi-friction plate. A clutch sleeve (29B) having an acting piston part is moved outside the spline 11x to form a front wheel speed increasing clutch (29), and a clutch sleeve (29B) is placed on the opposite side of the clutch case (29A) across the clutch sleeve (29B). (29B) and a front wheel constant velocity output gear (30) which can be freely engaged and disengaged by a pawl clutch are loosely fitted. Therefore, the clutch sleeve (29B
) is integrated with the clutch case (29A), the accelerating output is transmitted to the front wheel output shaft (31), and conversely, when it is integrated with the front wheel constant velocity output gear (30), the constant velocity output is transmitted. be done.

[Another example]

(2) The low-pass valve mechanism (20) may be constructed by connecting three or more low-pass valves with different pilot pressures in parallel.

O The selection switching means (22) may be a solenoid valve,
The electric circuit is activated by the signal of the sensor that detects the gear shift operation position.
A configuration may be adopted in which the valve is switched.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the pressure adjustment mechanism for a hydraulic clutch according to the present invention, and FIG. 1 is a hydraulic circuit diagram for the hydraulic clutch;
Fig. 2 shows the M4 configuration of the transmission, Fig. 3 is a graph showing the pressure increase characteristics of the pressure adjustment mechanism for the hydraulic clutch, and Fig. 4 shows the M4 configuration of the transmission.
The figure is a side view showing the mounted state of the transmission mechanism, and FIG. 5 is a configuration diagram showing the front wheel speed increasing mechanism incorporated in the transmission case. ((16)...,...pressure adjustment mechanism, (19)...
...High pass valve, (20)...Low pass valve mechanism, (20A). (20B)...Low pass valve, (21)...
... Throttle mechanism, (C) ... Hydraulic clutch for speed change.

Claims (1)

[Claims] A pressure adjustment mechanism (16) is provided in the pressure oil supply path to the transmission hydraulic clutch (C), and this pressure adjustment mechanism (
16), a low-pass valve mechanism (20) that is operated to close by pilot pressure on the secondary side, a high-pass valve (19) that is operated to open by pilot pressure on the secondary side, and a throttle mechanism (16) connected in parallel to these valves. 21), wherein the low-pass valve mechanism (20) is connected in parallel with a plurality of low-pass valves (20A) and (20B) having different pilot pressures. In addition, the selection switching means (2) connects the pressure oil passage from the pump (P) to the low-pass valve (20A) having a higher pilot pressure as the traveling gear position becomes higher.
2) A pressure adjustment mechanism for the hydraulic clutch.