JPH02303403A - Hydraulic control device in working vehicle - Google Patents

Abstract

PURPOSE:To lift a working device relatively rapidly to improve the accuracy of a rolling control when operated and when the frame is moved, by disposing two actuators for lifting and rolling operations in a specific hydraulic circuit. CONSTITUTION:The input port A of a lifting control valve V1 of an actuator C1 for a lifting operation is connected to the excessive flow port Y of a flow priority valve F, and the input port I of a rolling control valve V2 of an actuator C2 for a rolling operation is also connected to a control flow port Z. When the control V2 is set at a natural position, an oil route-switching valve 15 is switched into an operation state 15a by a switching valve control means, and when the control valve V2 is set at an actuator-driving position, the oil route- switching valve 15 is switched into an operation state 15b, thereby permitting to stably supply a pre-set amount of the oil to the actuator C2 and supply a relatively layer amount of the oil to the actuator C1.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a first hydraulic actuator for raising and lowering a working device with respect to the traveling machine body, and a first hydraulic actuator for rolling the working device with respect to the traveling machine body. The present invention relates to a hydraulic control device for a working vehicle, which includes two hydraulic actuators and a rolling control mechanism that automatically operates the second hydraulic actuator to bring the working device into a set posture.

[Conventional technology]

In the above-mentioned work vehicle, conventionally, for example,
As shown in Publication No. 2, the oil from the hydraulic pump is supplied to the rolling control valve through the control flow port of the flow priority valve, and the waste oil from the rolling control valve is directly supplied to the tank. By configuring the flow priority valve to return the oil and supplying only the oil from the surplus flow port of the flow priority valve to the lifting actuator, for example,
As shown in Japanese Patent No. 19312, oil from the hydraulic pump is supplied to the rolling control valve through the control flow port of the flow priority valve, and the oil discharged from the rolling control valve and the flow priority valve are By configuring the system to combine the oil from the surplus flow port and supply it to the lifting actuator,
Even if both the rolling and lifting actuators are driven by the same hydraulic pump, and even if the hydraulic pump's discharge volume changes due to changes in rotation speed, the flow priority valve allows the set flow rate of oil to be rolled. It has now become possible to stably supply the actuators for use.

[Problem to be solved by the invention]

In the former case, where only excess oil from the flow priority valve is supplied to the lifting actuator, when moving the aircraft from a parking place such as storage, a working device is lowered to the ground for safety when parking or parking. The problem was that it took a relatively long time to raise the temperature. This is because when working, the accelerator of the engine is set to high speed, so the rotation speed of the hydraulic pump also becomes high, and the discharge amount becomes relatively large, resulting in a relatively large amount of surplus oil from the flow priority valve. However, the working equipment can be raised relatively quickly even with excess oil.

However, when moving the aircraft, especially when the working equipment is slightly raised, the engine speed is set lower than the operating speed for safety reasons, and the hydraulic pump is rotated. This is because the speed is also slow and the discharge amount is relatively small, resulting in a relatively small amount of surplus oil from the flow priority valve.

On the other hand, in the latter case where drained oil from the rolling control valve and excess oil from the flow priority valve are combined and supplied to the lifting actuator, if both the lifting and lowering of the work equipment and the rolling control are performed simultaneously. When the rolling control valve switches, back pressure caused by the switching of the valve may cause malfunctions such as vibration in the lifting actuator, or back pressure caused by the switching of the lifting control valve. As a result, malfunctions such as vibrations may occur in the rolling actuator.

An object of the present invention is to enable stable driving of a rolling actuator, and to raise the working device relatively quickly both during work and when moving the machine, and to prevent the actuator from switching due to control valve switching. The purpose is to avoid malfunctions.

[Means to solve the problem]

To achieve the object, the present invention provides a hydraulic control system for a working vehicle as described at the beginning, in which an input port of a lift control valve for operating the first hydraulic actuator is connected to a hydraulic pump, and a surplus flow of a flow priority valve is provided. an input port of a rolling control valve for operation of the second hydraulic actuator is connected to a control flow port of the flow priority valve, and drain oil from the rolling control valve is connected to the input port of the lift control valve. An oil passage switching valve is provided that can be freely switched between a first operating state in which oil is merged and supplied to the port and a second operating state in which drained oil from the rolling control valve is returned directly to the tank, and the rolling control valve is in a neutral position. If so, the oil passage switching valve is automatically switched to the first operating state, and the rolling control valve is a hydraulic control device for an actuator driven vehicle. 3. A switching valve control means is provided for automatically switching the oil passage switching valve to the second operating state. Alternatively, a set amount of the hydraulic pressure supplied from the hydraulic pump is preferentially supplied to the rolling control valve for operating the second hydraulic actuator, and the remaining amount is supplied to the lifting control valve for operating the first hydraulic actuator. A supply valve mechanism that can freely switch between a branched supply state and a non-divided supply state in which the entire amount of oil supplied from the hydraulic pump is supplied only to the lifting control valve of the rolling control valve and the lifting control valve. and providing a drainage path for directly returning the drainage oil from the rolling control valve to the tank, and automatically switching the supply valve mechanism to the non-diversion supply state when the rolling control valve is in a neutral position; and,
A supply switching control means is provided for automatically switching the supply valve mechanism to the branch supply state when the rolling control valve is in the seven-way machine drive position.

In configuring the supply valve mechanism, it is advantageous to provide a flow priority valve and an electric actuator that switches the valve body of the flow priority valve between a diversion position and a non-division position.

[For production]

In other words, if the engine speed is set to high working speed,
Even if the oil passage switching valve is switched to the second operating state or the supply valve mechanism is switched to the branching state, the drained oil from the rolling control valve is returned directly to the tank, and the oil supplied from the hydraulic pump is Even if the first hydraulic actuator is driven by only a part of the flow priority valve or the supply valve mechanism that supplies the divided flow, the first hydraulic actuator can achieve the minimum high lifting speed required during work. The discharge capacity of the hydraulic pump is set so that oil can be supplied to the elevation control valve from the flow priority valve or supply valve mechanism. Then, during work, when the rolling control valve is in the neutral position, the oil passage switching valve is operated in the first working state, or the supply valve mechanism is operated in the non-diverting state, and the oil from the hydraulic pump is not supplied. The entire amount of oil is supplied to the elevation control valve, and as the driving operation by switching the elevation control valve is performed manually or automatically, the first hydraulic actuator is supplied with the entire amount of oil at a rate higher than the minimum high speed of elevation. Operates at high speed. and,
When the rolling control valve is switched to the actuator drive position, the oil passage switching valve is operated to the second operating state, or the supply valve mechanism is operated to the diverting state, so that only a portion of the oil from the hydraulic pump is supplied. Even if the first hydraulic actuator cannot be supplied, the supplied oil is the set amount of oil for lifting, and the first hydraulic actuator operates at the minimum high lifting speed.

Even if the discharge volume of the hydraulic pump becomes lower than the discharge volume during operation when the aircraft is moving, the pump performance can suppress the decrease so that it does not become large.
At this time, the running ground conditions are good and rolling control is rarely performed, and the rolling control valve is operated to the neutral position and the oil passage switching valve is automatically switched to the first operating state.
Alternatively, the supply valve mechanism is automatically switched to a non-dividing state and the entire amount of oil from the hydraulic pump is supplied to the lift control valve, so that when the lift control valve is switched, the first pressure actuator is activated. Full-oil operation allows it to operate at higher speeds than traditional non-merged feed types.

In other words, if the oil passage switching control means automatically operates the oil passage switching valve or the supply switching control means automatically operates the supply valve mechanism to set the discharge amount of the hydraulic pump to the aforementioned discharge amount, the rolling Diverting an amount of oil greater than the minimum required amount to the first hydraulic actuator while preventing the control valve from being connected to the oil path to the first hydraulic actuator and preventing the elevation control valve from connecting the oil path to the second hydraulic actuator. It becomes possible to supply or combine supply.

If the flow priority valve is equipped with an electric actuator to operate the valve body, and the divided flow supply and non-divided flow supply are switched by operating the valve body, the divided flow supply path, the non-divided flow supply path, and these supply paths can be selectively switched. Compared to providing respective oil passage switching valves connected to the hydraulic pump, it is possible to switch the supply while simplifying the structure on both the oil passage surface and the valve surface.

〔Effect of the invention〕

The set amount of oil is supplied to the second pump regardless of the change in the hydraulic pump discharge level.
It is possible to stably supply oil to the hydraulic actuator for accurate rolling control, and to supply a relatively large amount of oil to the first
Although the work equipment can be raised and lowered relatively quickly by supplying it to the hydraulic actuator, back pressure caused by switching of the rolling control valve and the lifting control valve affects the first hydraulic actuator and the second hydraulic actuator.
I was able to prevent this from occurring with the hydraulic actuator. Moreover, even when the machine is moving, a relatively large amount of oil is supplied to the first hydraulic actuator to speed up lifting of the working equipment, and overall work can be carried out efficiently with good finishing accuracy.

If the supply valve mechanism is constituted by a flow priority valve and an electric actuator that operates its valve body, the structure for switching between divided flow supply and non-divided flow supply can be simplified and advantages can be obtained in terms of cost and the like.

〔Example〕

Next, examples will be shown.

As shown in FIG. 8, a lift cylinder (as an example of a first hydraulic actuator) is installed at the rear of the wheeled traveling body (1).
The tiller (3) is connected to the rotary tiller (3) so that it can be raised and lowered by C1) via the link mechanism (2), and the tiller (3) is connected to the tiller (3) from the traveling body (1) via the rotating shaft (4).
The riding type cultivator is configured such that power is transmitted to the vehicle.

A pair of left and right lift arms (
5a), (5b) and a pair of left and right lower links (
6a) and (6b) are connected by a lift rod (7), the other lift arm (5b) and the other lower link (6b) are connected by a rolling cylinder (C2), and this rolling cylinder (C8) By expanding and contracting the plowing device (3), the tilling device (3) is configured to roll with respect to the traveling machine body for vertically swinging operation of the lower link (6b) by the rolling cylinder (C2) and flexibility of the link connection part. It is. That is, the rolling cylinder (C2) is an example of the second hydraulic actuator.
) allows the tilling device (3) to perform a rolling operation with respect to the traveling machine body (1).

As shown in FIG. 8, a tilt sensor (7) attached to the rear of the traveling body (1) is configured to detect the left and right inclination and the direction of inclination of the traveling body (1), and to extract the detection results as electrical signals, and the link The structure is such that a stroke sensor (B) attached to the mechanism (2) detects the length of expansion and contraction of the rolling cylinder (C) and extracts the detected length as an electric signal. ,
The inclination sensor (7) is connected to the rolling control mechanism (10) via the control target length setting means (9), and the rolling control mechanism (10) is connected to the stroke sensor (B
), and the driving circuit (11) of the rolling control valve (V2)
) are linked so that work can be carried out while maintaining the left and right plowing depths of the tilling device (3) the same or almost the same regardless of the left and right inclination of the traveling machine (1).

That is, the control target length setting means (9) uses the inclination sensor (
7) based on the detection results of the rolling cylinder (C2
) is configured to automatically set the control target length to be extended/contracted and output it to the rolling control mechanism (10). The rolling control mechanism (10) then sends a signal to operate the rolling control valve (V1) so that the control target length set by the setting means (9) and the length detected by the stroke sensor (B) are the same or almost the same. By automatically outputting to the drive circuit (11), the rolling cylinder (C2) is automatically brought into a state in which the tillage device (3) has a horizontal or almost horizontal posture when viewed in the front-rear direction, which is an example of a set posture. It is configured to operate.

In order to enable the driving of the lift cylinder (CI) and rolling cylinder (C), a hydraulic pump (P) is provided in the driving part of the traveling aircraft so as to be driven by the traveling engine (E), and a hydraulic circuit is installed in the driving part of the traveling aircraft. It is constructed as shown in FIG. 1 or 2.

That is, in the circuit shown in Fig. 1, the hydraulic pump (
A flow priority valve (F) is connected to the input port (I) of the rolling control valve (V2) so as to be supplied with oil via an oil line (12) to the flow priority valve (F) via an oil line (13). (P) Control Flow Port (Z)
and connect the input port (A) of the lift control valve (V1) for operating the lift cylinder (C1) to the surplus flow port (Y) of the flow priority valve (F) via the oil passage (14). The discharge port (0) of the rolling control valve (V2) is connected to the oil supply path (11) having the oil path switching valve (15).
) is connected to the oil passage (14). The oil passage switching valve (15) has a first operating state (15a) and a second operating state (
15b), and when switched to the first operating state (15a), the rolling control valve (V2 ) to the surplus port (Y
) into the inlet port of the lift control valve (V8).
4 (A) and is switched to the second operating state (15b), the rolling control valve (V2
) is configured so that the waste oil from the tank (T) is returned directly to the tank (T).

Then, as shown in FIG. 5, the rolling control mechanism (10)
is the rolling control valve (V2) in the switching valve control means (18).
) by configuring to output a signal to operate the oil passage switching valve in conjunction with the operation of the oil passage switching valve (15).
) is automatically switched as the rolling control valve (V2) is switched. That is, when the rolling control valve (V2) is in the neutral position, the switching valve control means (18) switches the oil passage switching valve (15) to the first operating state (15a) and operates the rolling control valve (V2).
) is in the cylinder drive position, the switching valve control means (
18) sets the oil passage switching valve (15) to the second operating state (15b).
).

In other words, both the lift cylinder (C1) and the rolling cylinder (C3) are driven by the same hydraulic pump (P), and even if the discharge amount of the hydraulic pump (P) changes, the flow priority valve(
F) preferentially supplies a set amount of the introduced oil from the control flow port (Z) to the rolling cylinder (C2).
It is designed to operate stably with a set amount of oil. Furthermore, when the rolling cylinder (C2) is not driven, the entire amount of oil from the hydraulic pump (P) causes the lift cylinder (
C1) is driven at high speed, and when the rolling cylinder (C) is driven, the rolling control valve (V2) or the elevation control valve (
The back pressure shock caused by switching of V1) is applied to the lift cylinder (C
1) or the lift cylinder (C
8) is to be driven.

In the circuit shown in Figure 2, a flow priority valve (F) is connected to the hydraulic pump (P) so that it is supplied with oil via an oil path (12), and an input port ( I) to the control flow port (Z) of the flow priority valve (F) via the oil line (13) and to the discharge port (0) of the rolling control valve (V2).
is connected to the tank (T) via the oil drain path (17), and a lift control valve (V2) for operating the lift cylinder (C1)
The input port (A) of is connected to the surplus flow port (Y) of the flow priority valve (F) via an oil line (14).

To configure the flow priority valve (F), the third
As shown in the figure, input port (x), surplus flow port (Y
) and a control flow port (Z), a cylindrical valve body (20) and a spring (21) acting on one end side of the valve body (20) are installed inside the valve case (19). An electromagnetic solenoid (23) acts on an operating tool (22) for sliding operation of the valve body 20) to switch the valve body 20).
) through the solenoid case (24) and the valve case (19).
), and is configured to be switched between a divided flow supply state and a non-divided flow supply state by operating the operating circuit of the solenoid (23).

That is, when the solenoid (23) is operated to a de-energized state, the valve body (20)
As shown in Fig. 3, the oil is at the branching position where it is received and supported by the end face of the valve body holder (25), and the oil introduced into the valve case (19) from the input port (X) flows through the valve body (20). The throttle part (20a) divides the control flow into a set amount of control flow and other surplus flow, and the control flow flows through the through hole (20b) of the valve body (20).
) and the through hole (25a) of the valve body holder (25) to flow to the control flow port (Z), and a branched flow supply state is established such that the surplus flow flows to the surplus flow port (Y). When the solenoid (23) is operated to be energized, the valve body (20) penetrates the valve holder (25) as shown in FIG. The hole (25a) is closed in a non-divided flow position, and a non-divided flow supply state is established such that the entire amount of oil introduced from the input port (X) flows only to the surplus flow port (Y).

Then, as shown in FIG. 6, the rolling control mechanism (10)
is connected to the supply switching control means (21) by the rolling control valve (V
By configuring to output a signal to operate the flow priority valve in conjunction with the operation of 2), the flow priority valve (F) can be configured to operate the rolling control valve (
The switching operation is automatically performed in conjunction with the switching of ν2).

That is, when the rolling control valve (V2) is in the neutral position, the supply switching circuit (21) switches the flow priority valve CF) to the non-divided flow supply state, and when the rolling control valve (V2) is in the cylinder drive position, the supply switching circuit (21) switches the flow priority valve CF) to the non-divided flow supply state. The switching circuit (21) is a flow priority valve (
F) is configured to be operated to switch to a branch supply state.

In other words, both the lift cylinder (C3) and the rolling cylinder (C2) are driven by the same hydraulic pump (P), and even if the discharge amount of the hydraulic pump (P) changes, the flow priority valve(
Due to the divided flow supply action of F), the rolling cylinder (C2
) to operate stably with a set amount of oil. Furthermore, when the rolling cylinder (C2) is not driven, the lift cylinder (C1) is driven at high speed by the entire amount of oil from the hydraulic pump (P) in order to switch the flow priority valve (F) to a non-divided flow supply state. When the rolling cylinder (C2) is driven, the rolling control valve (
The oil drain path (17) returns the drained oil from the tank (T) directly to the tank (T), and the back pressure impact caused by the switching of the rolling control valve (V2) or the lift control valve (V1) is transferred to the lift cylinder (C1). Alternatively, the lift cylinder (C,) may be driven while ensuring that the rolling cylinder (C2) is not affected.

[Another example]

FIG. 7 shows another embodiment of supply switching, and shows a hydraulic pump (P
) through the oil path switching valve (27), and connect the input port (■) of the rolling valve (V2) to the flow priority valve (F).
is connected to the control flow port (Z) of the lift control valve (
V2) input port (A) is connected to the surplus flow port (Y) of the flow priority valve (F) via the oil supply path (14).
and the oil passage switching valve (27), and the oil passage switching valve (27).
The supply valve mechanism (B) is configured to switch between the divided flow supply state and the non-divided flow state by switching 7).

That is, the oil passage switching valve (27) is in the first operating position (27).
When switched to a), by supplying oil from the hydraulic pump (P) to the flow priority valve (F),
This flow priority valve (F) is connected to the hydraulic pump (
The set amount of oil from the rolling control valve (V2
), and the remaining amount is supplied to the elevation control valve (V1) in a divided supply state. When the oil passage switching valve (27) is switched to the second operation position (27b), the oil from the hydraulic pump (P) is supplied only to the oil supply passage (14). A non-divided flow supply state is established so that the entire amount of is supplied only to the elevation control valve (V2). Then, the oil passage switching valve (27) is operated by the supply switching circuit (28) to control the rolling control mechanism (1).
The switching operation is automatically performed based on information from 0).

In addition to tillers, the present invention can also be applied to various work vehicles such as rice transplanters. Therefore, the tilling device (3) is referred to as a working device (3).

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 drawings]

The drawings show an embodiment of the hydraulic control device for a working vehicle according to the present invention, and FIGS. 1 and 2 are hydraulic circuit diagrams, and FIGS. 3 and 4 are hydraulic circuit diagrams.
5 is a sectional view of the flow priority valve, FIGS. 5 and 6 are block diagrams of the control system, FIG. 7 is a hydraulic circuit diagram of another implementation, and FIG. 8 is a schematic perspective view of the rear part of the riding type cultivator. (1)......Travelling body, (3)...Working device, (10)...Rolling control mechanism, (1
5)...Oil passage switching valve, (15a)...
・First operating state, (15b)...Second operating state, (18)...Switching valve control means, (20).
... Valve body, (23) ... Electric actuator, (21) ... Supply switching control means, (A
)...Manual port, (B)...Supply valve mechanism, (C2)...First hydraulic actuator,
(C2)・Old・・Second hydraulic actuator, (P)・・
... Hydraulic pump, (F) ... Flow priority valve, (Y) ... Surplus flow port, (
V1)...Elevation control valve, (V2)...
Rolling control valve, (T)...Tank, (I)
...Input port, (Z) ...Control flow port.

Claims (3)

[Claims] 1. A first hydraulic actuator (C_1) that raises and lowers the working device (3) with respect to the traveling machine body (1), and a second hydraulic actuator that performs a rolling operation of the working device (3) with respect to the traveling machine body (1). (C_2) and a rolling control mechanism (10) that automatically operates the second hydraulic actuator (C_2) so that the ground attitude of the work device (3) becomes the set attitude. A device, the first hydraulic actuator (
The input port (A) of the lift control valve (V_1) for operation of C_1) is connected to the surplus flow port (Y) of the flow priority valve (F) connected to the hydraulic pump (P), and the second hydraulic actuator (C_2) input port (I) of the rolling control valve (V_2) for operation of said flow priority valve (F) control flow port (Z)
a first operating state (15a) connected to the rolling control valve (V_1) and supplying waste oil from the rolling control valve (V_1) to the input port (A) of the elevation control valve (V_2); An oil passage switching valve (15) is provided which can be freely switched to a second operating state (15b) in which drained oil is directly returned to the tank (T), and the rolling control valve (
When V_2) is in the neutral position, the oil passage switching valve (15)
is automatically switched to the first operating state (15a), and when the rolling control valve (V_2) is in the actuator drive position, the oil passage switching valve (15) is switched to the second operating state (15a).
A hydraulic control device for a work vehicle, which is provided with a switching valve control means (18) that automatically switches to an operating state (15b). 2. A first hydraulic actuator (C_1) that raises and lowers the working device (3) with respect to the traveling machine body (1), and a second hydraulic actuator that performs a rolling operation of the working device (3) with respect to the traveling machine body (1). (C_2) and a rolling control mechanism (10) that automatically operates the second hydraulic actuator (C_2) so that the ground attitude of the work device (3) becomes the set attitude. The apparatus comprises a hydraulic pump (P) that controls a set amount of oil supplied from a hydraulic pump (P) to the second hydraulic actuator (C).
_2) is preferentially supplied to the rolling control valve (V_2) for operation, and the remaining amount is supplied to the first hydraulic actuator (V_2).
C_1) is supplied to the lift control valve (V_1) for operation, and the total amount of oil supplied from the hydraulic pump (P) is transferred to the rolling control valve (V_2) and the lift control valve (V_1). A supply valve mechanism (B) is provided that can freely switch between a non-divided supply state in which only the lifting control valve (V_1) is supplied, and the drained oil from the rolling control valve (V_2) is directly supplied to the tank (T). A drain passage (17) for returning oil is provided, and when the rolling control valve (V_2) is in the neutral position, the supply valve mechanism (B) is automatically switched to the non-division supply state, and the rolling control valve (V_2)
is a hydraulic control device for actuator driven vehicles. 3. To configure the supply valve mechanism, oil from the hydraulic pump (P) is introduced from the control flow port (Z) to the rolling control valve (V_2), and from the excess flow port (Y) to the elevation control valve (V_1). ), the valve body (20) of the flow priority valve (F) is located at a diversion position where the introduced oil of this flow priority valve (F) is diverted to the control flow port (Z) and the surplus flow port (Y). and a non-dividing position where the introduced oil flows only to the surplus flow port (Y), and the valve body (20
3. The hydraulic control system for a working vehicle according to claim 2, wherein said flow priority valve (F) is provided with an electric actuator (24) for switching operation.