JPS6343602B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating various double-acting hydraulic actuators, such as hydraulic cylinders.

Conventionally, in order to operate the above-mentioned double-acting type fluid pressure actuator, as shown in FIG. The operating valve was operated by switching between forward and reverse drive, but the responsiveness of the fluid pressure actuator 1 was poor when switching between forward and reverse drive, and problems such as hunting and chattering were likely to occur, especially when configuring an automatic control system. There were flaws.

To be more specific, according to the conventional operation method,
As shown in FIG. 4, when the actuator 1 is being driven in the forward direction and the operating valve is switched to the reverse driving position at point A along the dotted line a, the opening degree of the operating valve is generally small. Since the change in flow rate between actuators 1 is extremely small, the change in flow rate for actuator 1 is as shown by solid line b, and over time (△
A response delay corresponding to t) occurs.

The method of the present invention aims to eliminate the above-mentioned drawbacks, and provides a double-acting hydraulic actuator with a first operation valve that switches between driving the actuator in the forward direction and stopping it; A second operation valve for switching between a driving state and a stop state is connected in parallel, and when switching between forward and reverse driving of the actuator, one operation valve of the two operation valves is closed, and then the other operation valve is closed. It is characterized by partially overlapping the opening operations in time.

That is, when the first and second operation valves are operated as described above, for example, if the closing operation of one operation valve and the opening operation of the other operation valve overlap for a time corresponding to the aforementioned Δt, the result shown in FIG. , the operating valve that is closed is switched along the dotted line c, and the operating valve that is opened is switched along the dotted line d, and the flow rate change of the former operating valve is as shown by the solid line e, and The flow rate change of the latter operation valve is as shown by the solid line f, and as a result, compared to the conventional method described above, the time required for forward/reverse drive switching is maximized.
Not only is it possible to shorten the time corresponding to the above-mentioned △t, but also the responsiveness when switching between forward and reverse drives can be effectively improved, even when the fluid pressure actuator is operated by automatic control. too,
Ivy allows you to easily perform precise operations.

Next, embodiments of the present invention will be described with reference to illustrative drawings.

As shown in Fig. 1, the operating device for a double-acting fluid pressure cylinder 1 installed in construction machinery, agricultural machinery, and various other devices is configured to operate the cylinder 1 in the forward direction and in the stopped state. A two-position electromagnetic first operation valve 2 for switching, and a valve 2 for switching the cylinder 1 between driving the cylinder 1 in the opposite direction and stopping the cylinder 1.
A position type electromagnetic second operation valve 3 is interposed in parallel between the cylinder 1, the pump P, and the tank T. Then, there are three types: forward direction drive, stop, and reverse direction drive.
A sensor 5 for detecting the operating position is attached to the operating lever 4 whose position can be changed freely, and the first and second operating valves 2 and 3 are adjusted based on the information from the sensor 5.
A microcomputer 7 is provided which sends an operation signal to a power supply operation circuit 6 for controlling the first operation valve 2 or the second operation valve when the operation lever 4 is operated from the stop position to the forward or reverse drive position or vice versa. 3 is configured to be switched independently, and when the operating lever 4 is sequentially operated from the forward drive position to the reverse drive position or vice versa, one of the operating valves (2 or 3) is closed. and the subsequent opening operation of the other operation valve (3 or 2) as described above.
As shown in the figure, the operation valves (2 or 3) are closed by overlapping each other by time △t.
The flow rate of the operation valve (3 or 2), which is opened almost at the same time as the flow rate of the valve (3 or 2) suddenly decreases, is configured to suddenly increase.

Note that not only cylinders but also various double-acting fluid pressure actuators 1 such as motors can be operated.

As mentioned above, setting the overlap time Δt in the operation of both operating valves 2 and 3 to approximately twice the dead zone Δta of the operating valves is effective in quickly and smoothly switching the operation of the fluid pressure actuator 1. It is desirable to make the overlap time Δt large if it is desired to change the operation quickly, and to make the overlap time Δt small if it is desired to make the changeover smooth.

As mentioned above, when operating both operating valves 2 and 3 with an overlap time Δt, if a forward/reverse switching operation is performed within a set time using a timer, for example, one operating valve (2 or 3) is operated. 3) After the set time has elapsed after the start of the closing operation, the other operating valve (3 or 2)
The specific implementation method can be changed in various ways, such as configuring it to start the opening operation.

To operate both operation valves 2 and 3, the operation valves 2 and 3 may be driven mechanically or hydraulically, or
Various operating means can be applied, such as changing the swing lever 4 to a dial type or push button type manual operating tool, or an automatic operating mechanism.

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 method of operating a fluid pressure actuator according to the present invention, in which FIG. 1 is a circuit diagram of a fluid pressure system and an operation system, FIG. 2 is an explanatory diagram of operating characteristics, and FIG.
The figure is a conventional circuit diagram, and FIG. 4 is a diagram illustrating the conventional operating characteristics. 1... Actuator, 2, 3... Operation valve.

Claims (1)

[Claims] 1 A double-acting fluid pressure actuator 1 is provided with a first operating valve 2 that switches it between a state of driving it in the forward direction and a state of stopping it, and a second operating valve 3 that switches it between a state of driving it in the reverse direction and a state where it stops. When switching between forward and reverse drive of the actuator 1, one operation valve (2 or 3) of the operation valves 2 and 3 is closed, and then the other operation valve (3 or 2) is closed. A method of operating a fluid pressure actuator characterized by partially overlapping opening operations in time.