JPH01156147A - Hydraulic clutch for running service car - Google Patents

Abstract

PURPOSE:To reduce shocks in changing over a clutch by controllably maintain the internal pressure of each hydraulic clutch at predetermined pressure when an absolute value of acceleration of travelling system exceeds a predetermined value in changing over formed and backward hydraulic clutches. CONSTITUTION:In a clutch case connected to an input shaft of a travelling system are provided a first hydraulic clutch C1 for transmitting power from the input shaft to an output gear and a second hydraulic clutch C2 for transmitting power from the input shaft 4 directly to an input gear. In oil paths 23, 24 for sending pressurized oil from a hydraulic pump 21 through a forward and backward change-over valve 22 to the respective hydraulic clutches C1, C2 is provided a electromagnetic proportional pressure reducing valves V1, V2. These valves V1, V2 controllably maintain the pressure of oil supplied to the respective clutches C1, C2 by a controller 25 when an absolute value of acceleration detected by a sensor S in the travelling system exceeds a predetermined value in changing over the respective hydraulic clutches C1, C2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic clutch/notch device for driving a working vehicle,
Specifically, the present invention relates to a technique for reducing shock when engaging and operating a friction-type hydraulic clutch.

[Conventional technology]

Conventionally, as a technique for reducing the shock when engaging the hydraulic clutch as described above, there is a technique disclosed in Japanese Patent Application Laid-Open No. 62-2
No. 31841 G is disclosed, and in this reference, the pressure of hydraulic oil supplied to the hydraulic clutch is adjusted based on the acceleration of the traveling system when the hydraulic clutch is operated in the engaging direction. The clutch is configured to operate the clutch without performing the engagement operation slowly and without generating a shock.

[Problem that the invention seeks to solve]

Furthermore, when a friction type hydraulic clutch is engaged, a quick supply of pressure oil is required from the start of supply of pressure oil until the friction plates begin contact and reach a half-clutch state, and after reaching a half-clutch state, It is necessary to maintain this half-clutch state for an appropriate period of time while gradually accelerating.

Although it is possible to continue in a half-clutch state even with the structure of the above reference, it is possible to continue in a half-clutch state, but in a state where the vehicle body is moving due to inertia, for example, when the driving direction is changed from forward to reverse. Even when attempting to start traveling in the opposite direction to this moving direction, the same operation as starting from a stopped state will be performed, and the following phenomena may occur.

In other words, when the vehicle body is moving due to inertia force and you try to start traveling in the opposite direction to this direction of movement,
Even if the hydraulic clutch reaches a half-clutch state due to the supply of hydraulic oil, the power from the hydraulic clutch is initially consumed exclusively to reduce the vehicle speed, so the vehicle speed does not increase, and therefore the hydraulic oil continue to be supplied. Then, by the time the vehicle speed starts to increase, the hydraulic clutch reaches a state where it is almost engaged, and rapid acceleration begins, and only after this acceleration is fed-banked, control with predetermined characteristics is performed. It is also possible.

The purpose of the present invention is to generate a shock by continuing the half-clutch state for an appropriate amount of time even when the vehicle body is moving due to inertia and the vehicle attempts to start traveling in the opposite direction to the direction of movement. The object of the present invention is to configure a device that can smoothly start running without any trouble.

[Means for solving problems]

The features of the present invention include forward and reverse hydraulic clutches each configured as a friction type, a valve that adjusts the supply pressure of hydraulic oil to each of these hydraulic clutches, and a measuring means that detects the acceleration of the traveling system. In addition, a means for measuring the acceleration of the traveling system when hydraulic oil is supplied to the hydraulic clutch on the other side so as to operate one hydraulic clutch from an engaged state to a disengaged state and operate the other hydraulic clutch in an engaged direction. When the absolute value of this acceleration value reaches a predetermined value or more, the operation of a valve mechanism that supplies hydraulic oil at a set pressure is adjusted to maintain the supply pressure of the hydraulic oil. The functions and effects of the control means are as follows.

[For production]

If the above characteristics are configured as shown in FIGS. 1 and 2, for example, when one hydraulic clutch is operated in the disengage direction and the other hydraulic clutch is operated in the on direction, the flowchart shown in FIG. As shown in step #13, hydraulic oil is supplied that increases at a predetermined rate, and then, due to this supply, the hydraulic clutch (C) reaches a half-clutch state,
When the acceleration value (x) measured by the measuring means (S) reaches a preset value (β) (#14, #15, #16
(Stesop), the hydraulic oil supply pressure will be maintained at a predetermined value.

In other words, a predetermined value of acceleration is measured.
Since the hydraulic clutch has already reached the half-clutch state, once this state is reached, the half-clutch state can be maintained and the speed increased sufficiently by simply supplying hydraulic oil at a constant pressure. Since the value of acceleration can be set arbitrarily, by setting this value smaller than the value for control when starting from a stop, the hydraulic clutch will not fall into a connected state when the vehicle speed increases.

In addition, if this operation is expressed in graphs corresponding to the current value of the operation signal, vehicle speed, and acceleration change, Figure 4 (a) and (l
]) , (c).

[Effect of idea]

Therefore, even if the vehicle tries to start traveling in the opposite direction to the direction of movement while the vehicle is moving due to inertia, the half-clutch state will continue for an appropriate period of time to ensure smooth travel without causing shock. A device was constructed that could start the process.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

As shown in FIG.
), the power from the running latch (2) is transmitted to the cylindrical input shaft (4) for the running system, and the power from the external clutch (3) drives the external power shaft (5). The signal is transmitted to a transmission shaft (6) that fits inside the input shaft (4) for the purpose of transmitting the signal.

As shown in the figure, a clutch case (8) is externally fitted and fixed to the input shaft (4) via a key (7), and
The output gear (9) is fitted on the outside in an idling state, and the input shaft (4)
) An input gear (11) is externally fitted and fixed to a cylindrical intermediate shaft (10) disposed coaxially with the input gear (11).

Moreover, an idle gear (12) and two gears (13) and (14) are connected between the output gear (9) and the input gear (11).
) is formed, and the clutch case (8) transfers the power from the input shaft (4) to the output gear (
9) and the input shaft (4).
) and a second hydraulic clutch (C2) that directly transmits power from the input gear (11) to the input gear (11), and both the first and second hydraulic clutches (CI) and (cz) have a large number of friction plates (15) and
・, (16)... and hydraulic piston (17) , (
18), each hydraulic clutch (CI)
, (Cz) can be set to a transmission state by supplying pressure oil.

Incidentally, the power from the intermediate shaft (10) is transmitted to the transmission device (1
A transmission system is formed in such a way that the power is transmitted to the wheels (20) via 9). Further, this transmission system is configured to be included in an agricultural tractor, and in this transmission system for traveling, the first
, the second hydraulic clutch (CI), and the first hydraulic clutch (CZ) in order to minimize shock during gear changes.
, a second hydraulic clutch (CI), (C2).

In other words, as shown in Fig. 1, pressure oil from the hydraulic pump (21) is sent to the forward/reverse switching valve (22);
2) to the first and second hydraulic clutches (C+).

(C2) Oil passages (23) and (24) that send pressure oil to each
are respectively equipped with electromagnetic proportional pressure reducing valves (V+), (Vz), and these two electromagnetic proportional pressure reducing valves (V+), (Vz)
(an example of a valve mechanism) is a microprocessor (not shown)
The control device (25) includes a changeover switch (26) for detecting the operating position of the valve (22) and the wheel (20).
A control system is formed such that a signal from a sensor (S) (an example of a measuring means) that detects the acceleration of the running system from the rotation of the wheel is input, and this control device (25) is programmed to operate according to the flowchart shown in FIG. is set, and
This program includes a control means (T
) is formed, and the operation of the control device (25) will be described below based on a flowchart.

That is, when the vehicle body is in a stopped state and is traveling forward, the traveling direction is determined (#1 step), and a large amount of hydraulic oil is supplied to the hydraulic clutch on the traveling direction side for a time (TI),
Further, the hydraulic pressure supplied to the hydraulic clutch is increased at a predetermined rate (steps #2 and #3).

This operation is performed by changing the control current value for the electromagnetic proportional pressure reducing valve (V) as shown in the graph of Figure 4 (a), and this pressure reducing valve (V) supplies hydraulic oil in response to increases and decreases in the current value. The reason why it is configured to increase and decrease the pressure and supplies a large amount of hydraulic oil as mentioned above is that the distance between the friction plates of the hydraulic clutch on the side to be engaged is narrowed in advance (by doing so, it is possible to This is to shorten the time required.

Next, the value (x) of the acceleration of the vehicle body is input based on the signal from the sensor (S), and a predetermined value (
α) (steps #4 and #5), it is determined whether the hydraulic clutch has reached a half-clutch state and an increase in vehicle speed has started.

Also, when the vehicle speed is recognized to increase in steps #4 and #5, the increase in the hydraulic oil supply pressure is stopped (step #6), and the half-clutch state is continued while the timer is set. (
The speed is increased by T2) (17,118 steps), and then the hydraulic oil is increased to the maximum value and the hydraulic clutch is set to a fully engaged state (#9 step).

Also, after the vehicle body has started moving forward in this way, when the direction of movement is changed (#10 step), oil is drained from the engaged hydraulic clutch (#11 step).
, Next, similarly to step #2, a large amount of hydraulic oil is supplied for the time (T, ) to the hydraulic clutch on the side that is newly engaged and operated (step #12), and the hydraulic oil is supplied with the specified pressure characteristics (Step #13).

Note that when the direction of travel is switched in this way, the vehicle is moving forward due to inertia, so the initial power when the hydraulic clutch on the reverse side reaches the half-engaged state is consumed for deceleration. In consideration of this, the pressure characteristic of #13 step is set lower than the increase rate of #3 step.

Next, while hydraulic oil is being supplied with the predetermined pressure characteristics as described above, the acceleration (x) of the vehicle body is input based on the signal from the sensor (S), and the preset value ( β
) (steps #14 and #15), it is determined whether the hydraulic clutch has reached a half-clutch state and the vehicle body has started to increase in the changed side (reverse direction) (#14, #15 step).

Incidentally, as mentioned above, since the initial power when the hydraulic clutch reaches the half-clutch state is consumed for deceleration, even if a relatively low acceleration is detected, the power will be lost after the hydraulic clutch reaches the half-clutch state. It can be inferred that a certain amount of time has passed, and for this reason, the predetermined value (β)
By setting the value appropriately lower than the predetermined value (α), it is possible to detect a half-clutch state when the vehicle is started from a stopped state.

Also, if the vehicle speed is increased in steps #14 and #15,
Stop increasing the hydraulic oil supply pressure (#16 step),
While maintaining the half-clutch state, the speed is increased for the time (T3) set in the timer (steps #17 and #18).
After this, the hydraulic oil is increased to the maximum value and the hydraulic clutch is set to the fully engaged state. And #13
~#16 steps are referred to as control means (T).

If the above operation is expressed in a graph based on the current value of the operation signal to the electromagnetic proportional pressure reducing valve, vehicle speed, and vehicle acceleration variation, it will be drawn as shown in Figure 4 (A), (II), and (C). It is.

Note that the sensor (S) is connected to the drive shaft (20a) of the wheel (20).
) is configured to detect the rotation of a gear (27) attached to a pickup-type coil (28).

[Another example]

In addition to the embodiments described above, the present invention may be applied to, for example, a multi-stage transmission system, or may be installed in a face shovel vehicle, a forklift vehicle, etc., and the control means may be a combination of a comparator, a logic gate, etc. It may also be configured in hardware.

Furthermore, the measuring means (S) can be configured in various ways, such as an optical sensor type or a power generation type, and the valve mechanism can also be implemented in various ways other than the electromagnetic proportional pressure reducing valve.

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 hydraulic pressure system for driving a working vehicle according to the present invention, FIG. 1 is a block diagram of the control system of the device, FIG. 2 is a schematic diagram of the transmission system, and FIG. 3 is a control system. A flowchart showing the operation of the device, Fig. 4(a) is a graph of the control signal for the electromagnetic proportional pressure reducing valve at the start of travel, Fig. 4(a)
TI) is a graph representing the vehicle speed at the start of travel, and FIG. 4(C) is a graph representing the acceleration of the vehicle body at the start of travel. (C1), (Cz)...Hydraulic clutch, (S)
...Measurement means, (T) ...Control means,
(V+), (VZ)... Valve mechanism.

Claims (1)

[Claims] Forward and reverse hydraulic clutches (C_2) and (C_1) each configured as a friction type; a valve (V_2) that adjusts the supply pressure of hydraulic oil to each of these hydraulic clutches (C_2) and (C_1); (V_1) and a measuring means (S) for detecting the acceleration of the traveling system, and the other side is provided with a measuring means (S) for detecting the acceleration of the traveling system, and one hydraulic clutch is operated from the engaged state to the disengaged direction, and the other hydraulic clutch is operated in the engaged direction. Determining the acceleration of the traveling system when hydraulic oil is supplied to the hydraulic clutch based on the detection signal from the measuring means (S),
A control means (T) is provided for adjusting the operation of a valve mechanism that supplies hydraulic oil at a pressure set to maintain the supply pressure of the hydraulic oil when the absolute value of the acceleration value reaches a predetermined value or more. Hydraulic clutch device for traveling of work vehicles.