JPH0210801Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The invention is applicable to, for example, a track bed compaction machine used to compact ballast during track straightening, a compactor used to compact track beds, and ballast on sleepers. This relates to a hydraulic circuit that controls two hydraulic motors installed in track maintenance work machines such as ballast sweepers that are to be removed.In particular, the number of directional control valves has been reduced to simplify the configuration, and the hydraulic motor that is to be stopped is overloaded. This invention relates to a hydraulic motor stop switching circuit designed to prevent oil pressure from being damaged in the first place.

[Prior Art] Hydraulic systems have many advantages such as flexibility of movement and ease of handling, and are widely used in various fields such as various machine tools and wheeled conveyance equipment.Due to recent remarkable technological developments, the demand for hydraulic systems has increased. Its use is expanding year by year. Among circuits using such hydraulic devices, many hydraulic circuits used particularly in track maintenance work machines and the like are provided with a plurality of hydraulic motors. For example, in the case of a ballast compactor that compacts track ballast, one set of ballast compacts is installed for each left and right rail, and each rail can compact the ballast inside and outside the rail independently. There are two pairs inside and one outside. Therefore, this ballast compactor requires two hydraulic motors each for vibrating the compact plates of the ballast compact inside and outside the rail.

By the way, in order to drive two hydraulic motors in this manner, a parallel connection of hydraulic motors as shown in FIG. 2 has conventionally been used. In this way, when stopping only one motor (for example, A) of the two motors A and B connected in parallel to the pressure line P and tank line T, the circuit on the motor A side must be A flow control valve is required to prevent a large amount of oil from flowing into the motor B at the same time as the motor B is disconnected. Furthermore, it is necessary to construct a circuit that will prevent motor A from suddenly stopping when the circuit on the motor A side is disconnected.

In order to satisfy the above conditions, as an example, two-position directional control valves connected in series for motors A and B are connected in parallel between pressure line P and tank line T, as shown in Figure 3. , flow control valve z
A hydraulic circuit is employed in which a two-position directional control valve c is connected in series and connected in parallel to motors A and B.

In this circuit, when the two motors are operating, oil does not flow through the flow control valve z, and since the directional control valves a and b connected in series to each motor are as shown in the diagram, each motor Oil flows through A and B, and both motors are rotating.

In this state, for example, if you want to stop only motor A, switch the directional control valve a on the motor A side to the stop side, and at the same time switch the directional control valve c connected in series to the flow rate control valve z to the open side. flows into the tank T via the flow rate control valve z, and is designed to prevent excessive flow from flowing to the motor B side.

However, when switching each directional control valve as described above, the following problems occur.

First, when operating manually, directional control valve a and directional control valve c are switched using respective operating levers.
If the two valves are not switched at the correct timing, excessive flow may temporarily flow into motor B, causing problems such as damage to motor B, or conversely, the flow control valve may open first. This causes problems such as a decrease in the flow rate to motor B, which continues to operate, and a decrease in its torque.

It is also possible to use electromagnetic directional control valves to time the switching operations of each directional control valve, but in that case, there would be three electromagnetic directional control valves and the control sequence would be complicated. This was not a desirable method.

[Problems to be solved by the invention] The present invention was proposed to solve the problems of the prior art as described above, and its purpose is to:
Even when the number of directional control valves is reduced to two and switching control is performed manually, the switching timing of both directional control valves can be easily synchronized, which prevents damage to hydraulic drive parts such as motors. It is an object of the present invention to provide a hydraulic stop switching circuit which is free from inconvenience and can simplify the sequence and other control system structures when an electromagnetic directional control valve is used.

[Means for solving the problem] The hydraulic stop switching circuit according to the present invention has a 4-port, 3-position directional control valve, a flow rate control valve, and a check valve between the pressure line P and the tank line T. By connecting two hydraulic drive units with each other and mechanically or electrically interlocking each of the directional control valves, the two directional control valves can control the operation of both hydraulic drive units or the stoppage of one of them. This is what I did.

In addition, a buffer circuit is formed with a check valve in each hydraulic drive section, so that even if one hydraulic drive section is stopped, oil is circulated through the check valve so that the hydraulic drive section can be gradually stopped. This is what I did.

[Example] An example of the hydraulic stop switching circuit according to the present invention described above will be specifically described with reference to the drawings.

In Fig. 1, first and second hydraulic motors A and B are connected in parallel between a pressure line P and a tank line T via four-port, three-position directional control valves a and b. ing. Each direction control valve a,
In b, the pressure line P is connected to the first port, the second port is connected to the hydraulic motor A or B, and the third port is connected to the tank line T via the flow control valve z. Note that the fourth port is blocked.

These directional control valves a and b have three positions: a center position, straight positions on both sides thereof, and cross positions. and,
In the center position of the directional control valve a on the motor A side, the first port on the pressure line side of the four ports is connected to the second port on the motor A side, and in the straight position, the first port on the pressure line side is connected to the second port on the pressure line P side. and the second port on the motor A side, and in the cross position, the first port on the pressure line side and the third port on the flow control valve z side.
It is designed to be connected to the port. In addition, in the center position of the directional control valve b on the motor B side, the first port on the pressure line P side and the second port on the motor B side are connected, and in the straight position, the first port on the pressure line side is connected. port and the third port on the flow control valve z side are connected, and in the cross position, the first port on the pressure line P side is connected.
The port is connected to a second port on the motor B side.

Furthermore, check valves x,
In addition, the inlets of check valves x and y are connected to each other, and each motor A and B is connected to each check valve x and y.
and form a buffer circuit.

Further, in the illustrated embodiment, the two directional control valves a and b are switched by manual operating levers, and the respective operating handles are connected so that both valves move simultaneously. Note that when each of the directional control valves a and b is an electromagnetic directional control valve, the solenoids of both are connected in parallel.

The operation of the present invention having the above configuration is as follows.

That is, first, when motors A and B are operated simultaneously, directional control valves a and b are set to the center position. Then, in both directional control valves a and b, the first port on the pressure line side and the second port on each motor side are connected, and hydraulic pressure is supplied to both motors A and B.

From this state, only motor A is operated, and motor B
To stop the directional control valves a and b, operate the mutually connected operation levers of the directional control valves a and b at the same time and switch each directional control valve a and b to the straight position. Since the operation handles are connected, The two directional control valves a and b are simultaneously switched to the straight position without timing deviation. Then, the operation of motor A continues as it is, and on the other hand, in the directional control valve b on the motor B side, the first port on the pressure line P side is connected to the third port on the flow control valve z side.
Since it is connected to the port, the supply of hydraulic pressure to motor B is stopped. In this case, the hydraulic pressure supplied from the pressure line P to the directional control valve b on the motor B side is sent to the tank line T via the flow rate control valve z connected to the third port of the directional control valve b. The flow rate control valve z becomes a load in place of the stopped motor B.

By the way, even if oil pressure is no longer applied to motor B in this way, motor B continues to rotate due to inertia, and the pipe connecting the second port of directional control valve b and motor B becomes negative pressure, causing the motor to rotate due to inertia. Since the oil from B returns to motor B via the check valve y constituting the buffer circuit, motor B continues to rotate without suddenly stopping, and is gradually decelerated to a stop.

On the other hand, in order to stop motor A, if each directional control valve a, b is switched to the cross position side, then, contrary to the above, the oil pressure to the motor A side is changed to the tank line T.
The motor A is then gradually stopped via the check valve x of the buffer circuit. Also, motor B is
Since the first port on the pressure line P side of the directional control valve B and the second port on the motor B side are connected, rotation continues.

As described above, according to the hydraulic stop switching circuit of this embodiment, two directional control valves, a check valve,
Using the flow rate control valve, it is easy to operate two motors at the same time or stop only one of them. In particular, the number of directional control valves has been reduced to two, and either motor can be stopped by interlocking the directional control valves with a control lever and operating them in the same direction. This eliminates misalignment, and also eliminates accidents such as damage to the motor due to excessive pressure being applied to the stopped motor due to the buffer circuit consisting of the check valve. Furthermore, since the number of directional control valves is reduced compared to the conventional one, the sequence can be simplified even when electromagnetic directional control valves are used.

The present invention is not limited to the above-mentioned embodiments, and the connections of each port at the center position of each directional control valve can be changed by appropriately selecting the ports connected to the pressure line, tank line, and each motor. Alternatively, it is also possible to reverse the straight and cross positions of one directional control valve. Furthermore, although the illustrated embodiment uses two motors as hydraulic circuits to be switched, the present invention can also be used to control two sets of hydraulic drive units having various other actuators.

[Effects of the invention] As explained above, according to the invention, the simple structure of having two directional control valves and mechanically or electrically connecting the control means of the two directional control valves allows manual operation. Switching can be done easily without fear of timing deviation when operating the motor, and the motor will not be damaged even if excessive oil pressure is applied to the stopped motor, and the sequence is simple even when using a solenoid valve. It is possible to provide an excellent hydraulic stop switching circuit that can be used in various ways, and its effects are extremely large.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an example of a hydraulic stop switching circuit according to the present invention, Fig. 2 is a schematic circuit diagram showing an example of a circuit in which two hydraulic motors are connected in parallel, and Fig. 3 is a circuit diagram showing an example of a circuit in which two hydraulic motors are connected in parallel. FIG. 2 is a circuit diagram showing a conventional circuit in which a directional control valve for stopping a hydraulic motor is provided in the circuit shown in FIG. 2; A, B...Hydraulic motor, P...Pressure line, T
... Tank line, a, b, c ... Directional control valve,
x, y...check valve, z...flow control valve.

Claims (1)

[Claims for utility model registration] Between the pressure line and the tank line, there are two
A first and a second hydraulic drive section are arranged in parallel via a port 3-position type directional control valve, and a check valve is connected in parallel to each of these hydraulic drive sections, and the oil of this check valve is The inlets of the valves are connected to each other, and each check valve is connected to the tank line to form a buffer circuit, and the first port of each directional control valve is connected to the pressure line,
The second port is connected to the corresponding hydraulic drive of each directional control valve, the third port is connected to the tank line via the flow control valve, the fourth port is blocked, and the first directional control valve is connected to: The first port and the second port are connected in the center position and the straight position, and the first port and the third port are connected in the cross position, and the second directional control valve is connected in the center position and the cross position. means that the first and second ports are connected, and in the straight position, the first and third ports are connected, and the control levers of each directional control valve are mechanically or electrically interlocked. Features a hydraulic stop circuit.