JP6776977B2 - Hydraulic brake release device - Google Patents

Description

The present invention relates to a hydraulic brake release device.

Patent Document 1 below discloses a negative brake release device capable of releasing the brake of a traveling motor even when the engine of a construction machine is stopped. This negative brake release device releases the brake of the traveling motor by accumulating the brake release oil in the accumulator in advance and supplying the brake release oil to the brake release cylinder when the engine is stopped. ..

JP-A-2002-053027

By the way, in the above background technology, a hydraulic circuit for supplying brake release oil to a brake release cylinder via a parking brake solenoid valve (switching valve) and a brake valve is adopted, but a spool type main valve is provided. Since a 2-position 3-port valve (spool valve) is used for the brake valve, there is a risk of brake release oil leaking. If there is a leak of the brake release oil, the time during which the brake of the traveling motor can be released is shortened after the engine is stopped. Therefore, the leak of the brake release oil is a serious problem depending on the application of the construction machine.

The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress or eliminate leakage of brake release oil as compared with the conventional case.

In order to achieve the above object, in the present invention, as a first solution relating to the hydraulic brake release device, supply of brake release oil from the pressure supply source to the brake release cylinder and from the brake release cylinder to the hydraulic tank. A hydraulic brake release device having a brake control valve for switching between recovery of brake release oil and supplying the brake release oil pre-accumulated in the accumulator to the brake release cylinder to release the brake. A first non-leak type electromagnetic valve provided between the brake control valve and the brake release cylinder and switching connection / non-connection between the brake control valve and the brake release cylinder, and the first non-leak type. A second non-leak type that is provided between the electromagnetic valve and the brake release cylinder and the accumulator and switches the connection / non-connection between the first non-leak type electromagnetic valve and the brake release cylinder and the accumulator. A means is adopted that includes an electromagnetic valve and a control unit that controls the brake control valve, the first non-leak type electromagnetic valve, and the second non-leak type electromagnetic valve by switching between energization and de-energization of the drive current. To do.

In the present invention, as a second solution for the hydraulic brake release device, in the first solution, the control unit connects the second non-leak type solenoid valve to the connected state and the first non-leak. By setting the solenoid valve in the non-connected state, the brake release cylinder is put into the parking brake release state.

In the present invention, as a third solution relating to the hydraulic brake release device, in the second solution, the control unit uses the first non-leak type solenoid valve before setting the second non-leak type solenoid valve to the connected state. A means of setting the non-leak type solenoid valve to the non-connected state is adopted.

In the present invention, as a fourth solution relating to the hydraulic brake release device, in any of the first to third solutions, the brake control valve has the first non-leakage when the drive current is not energized. The solenoid valve is connected to the hydraulic tank, the first non-leak solenoid valve is connected to the brake control valve and the brake release cylinder, and the second non-leakage solenoid valve is the first non-leakage solenoid valve. A means of disconnecting the non-leak type solenoid valve, the brake release cylinder, and the accumulator is adopted.

In the present invention, as a fifth solution for the hydraulic brake release device, in any of the first to fourth solutions, the traveling hydraulic machine that can be remotely controlled from the outside is provided with the control unit. Adopts a means of controlling the brake control valve, the first non-leakage solenoid valve, and the second non-leakage solenoid valve based on a remote control command received from the outside.

According to the present invention, since the first non-leak type solenoid valve and the second non-leak type solenoid valve are provided, it is possible to suppress or eliminate the leakage of the brake release oil as compared with the conventional case.

It is a hydraulic circuit diagram which shows the structure of the hydraulic brake release device which concerns on one Embodiment of this invention. It is a hydraulic circuit diagram which shows the parking brake release preparation state of the hydraulic brake release device which concerns on one Embodiment of this invention. It is a hydraulic circuit diagram which shows the parking brake release state of the hydraulic brake release device which concerns on one Embodiment of this invention. It is a hydraulic circuit diagram which shows the parking brake release state at the time of engine rotation in the hydraulic brake release device which concerns on one Embodiment of this invention. It is a hydraulic circuit diagram which shows the unload state of the brake release oil from an accumulator in the hydraulic brake release device which concerns on one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the hydraulic brake release device according to the present embodiment includes a filter 1, a brake control valve 2, a check valve 3, a supply control valve 4, an accumulator 5, a pressure gauge 6, a hydraulic tank 7, and a control unit 8. I have.

This hydraulic brake release device is provided in a traveling hydraulic machine such as a construction machine, and the operating state of the brake releasing cylinder X (hydraulic cylinder) provided in the traveling motor (hydraulic motor), that is, the brake state and the brake. Set the release state alternately. In the traveling hydraulic machine, pressure oil is generated by a hydraulic pump that is rotationally driven by the engine during normal operation and is supplied to the hydraulic brake release device. The hydraulic pump is the supply pressure source in the present invention.

The filter 1 is a hydraulic device that removes impurities contained in the pressure oil supplied from the hydraulic pump, and supplies the pressure oil from which the impurities have been removed to the brake control valve 2. The brake control valve 2 is a 3-port 2-position solenoid valve as shown in the figure. The brake control valve 2 switches three internal flow paths by setting the position of the main valve to one of the two by a solenoid. The structure of the main valve in the brake control valve 2 may be either a spool type or a poppet type.

Such a brake control valve 2 is connected to the filter 1, the check valve 3 and the hydraulic tank 7 via a flow path formed in the first manifold M1 as shown in the figure. That is, the brake control valve 2 switches between supplying / stopping the supply / supply of the pressure oil supplied from the filter 1 to the check valve 3, and also supplies / stops the supply / supply of the pressure oil supplied from the check valve 3 to the hydraulic tank 7. Switch the supply stop.

The check valve 3 is a 2-port 2-position solenoid valve as shown in the figure. The check valve 3 switches between a conduction state and a cutoff state by setting the position of the main valve to either of the two by a solenoid. The check valve 3 is a non-leak type solenoid valve (first non-leak type solenoid valve) having a poppet-type main valve structure. Instead of the check valve 3, a switching valve that switches between a conduction state and a cutoff state may be adopted.

Here, the term "non-leak type solenoid valve" used in the present application means that the leakage of pressure oil is smaller than that of the conventional 2-position 3-port valve (spool valve), and there is no leakage of pressure oil. It does not mean that.

Such a check valve 3 is connected to the supply control valve 4 and the brake cylinder X via a flow path formed in the second manifold M2 as shown, and is also formed in the first manifold M1. It is connected to the brake control valve 2 via the flow path and the flow path formed in the second manifold M2. That is, the check valve 3 switches the connection / disconnection between the brake control valve 2, the supply control valve 4, and the brake cylinder X.

The supply control valve 4 is a 2-port 2-position solenoid valve as shown in the figure. The supply control valve 4 switches between a conduction state and a cutoff state by setting the position of the main valve to either of the two by a solenoid. The supply control valve 4 is a non-leak type solenoid valve (second non-leak type solenoid valve) having a poppet-type main valve structure. Instead of the supply control valve 4, a switching valve that switches between a conduction state and a cutoff state may be adopted.

Such a supply control valve 4 is connected to a check valve 3, a brake cylinder X, an accumulator 5, and a pressure gauge 6 via a flow path formed in the second manifold M2. That is, the supply control valve 4 switches the connection / disconnection between the check valve 3 and the brake cylinder X and the accumulator 5 and the pressure gauge 6.

The accumulator 5 is connected to the supply control valve 4 and the pressure gauge 6 via a flow path formed in the second manifold M2. The accumulator 5 is a pressure accumulator that accumulates pressure oil supplied from a hydraulic pump (supply pressure source) as brake release oil via a brake control valve 2, a check valve 3, and a supply control valve 4. The accumulator 5 also functions as a supply pressure source instead of the hydraulic pump, and supplies the brake release oil to the brake cylinder X via the supply control valve 4.

The pressure gauge 6 is connected to the supply control valve 4 and the accumulator 5 via a flow path formed in the second manifold M2. The pressure gauge 6 measures and displays the pressure of the brake release oil in the accumulator 5. The hydraulic tank 7 is a container for pressure oil having a predetermined capacity, and is connected to the brake control valve 2 via a flow path or the like formed in the first manifold M1. The hydraulic tank 7 collects and stores pressure oil from the brake control valve 2.

The control unit 8 is an electronic device that controls the above-mentioned three solenoid valves, that is, a brake control valve 2, a check valve 3, and a supply control valve 4. The control unit 8 connects the brake control valve 2, the check valve 3, and the supply control valve 4 by switching the supply / non-supply of the drive current to the brake control valve 2, the check valve 3, and the supply control valve 4. Set to status / disconnected status. Further, the control unit 8 has a communication function with the outside, and operates based on a remote control command received from the outside. That is, the traveling hydraulic machine according to the present embodiment is freely configured to be remotely controlled from the outside.

Next, the time-series operation of such a hydraulic brake release device will be described in detail with reference to FIGS. 2 to 5. In FIGS. 2 to 5, the solenoid valve in the state where the drive current is not energized (non-energized state) is shown by a solid line, and the solenoid valve in the state where the drive current is energized (energized state) is shown by a dotted line. ing.

Here, FIG. 1 described above shows a non-energized state of the brake control valve 2, the check valve 3, and the supply control valve 4. That is, in the non-energized state of the three solenoid valves, the brake control valve 2 connects the check valve 3 and the hydraulic tank 7, and the check valve 3 connects the brake control valve 2 and the brake cylinder X. Further, the supply control valve 4 does not connect the check valve 3, the brake cylinder X, and the accumulator 5.

In such a non-energized state, the pressure oil of the brake cylinder X is collected in the hydraulic tank 7 via the check valve 3 and the brake control valve 2, and the accumulator 5 is in an isolated state. For example, when the engine of the traveling hydraulic machine is completely stopped, the pressure oil of the brake cylinder X is collected in the hydraulic tank 7. As a result, the brake cylinder X is in a state in which the parking brake is applied to the traveling motor of the traveling hydraulic machine (parking brake state). Further, the accumulator 5 is maintained in the accumulator state.

Even when the engine is stopped and the main function of the traveling hydraulic machine is stopped, the control unit 8 can receive a remote control command from the outside by supplying power from the battery. Therefore, when the control unit 8 receives the remote operation command for shifting the brake cylinder X from the parking brake state to the parking brake release state, the control unit 8 energizes the check current prevention valve 3 as shown in FIG. , The brake control valve 2 and the brake cylinder X are disconnected.

As a result, the connection between the brake cylinder X and the hydraulic tank 7 is disconnected, and the two are disconnected. In the energized state of only the check valve 3, the brake cylinder X is released from the parking brake state. This is the state of preparation for shifting to (parking brake release preparation state).

In such a parking brake release ready state, the control unit 8 energizes the supply control valve 4 in addition to energizing the drive current to the check valve 3 as shown in FIG. That is, by energizing the check valve 3 and the supply control valve 4, the check valve 3 is set to the non-connected state, and the supply control valve 4 is set to the connected state.

As a result, the brake release oil stored in the accumulator 5 is supplied to the brake cylinder X as shown in the stage before the traveling hydraulic machine is completely stopped. That is, the traveling hydraulic machine changes from the parking brake release ready state to the parking brake release state.

As described above, in the hydraulic brake release device according to the present embodiment, the control unit 8 connects the supply control valve 4 (the second non-leak type solenoid valve) and the check valve 3 (the first non-leak type solenoid valve). By setting the valve) to be non-connected, the brake release oil of the accumulator 5 is supplied to the brake cylinder X, and thus the brake release cylinder X is put into the parking brake release state. Therefore, according to this hydraulic brake release device, it is possible to suppress or eliminate the leakage of the brake release oil as compared with the conventional case.

Further, in this hydraulic brake release device, since the leakage of the brake release oil is small, the pressure accumulator state of the accumulator 5 can be extended for a longer time than before. In addition, a state in which pressure oil for releasing the brake cannot be obtained from the hydraulic pump (supply pressure source) (that is, a state in which the engine has stopped (cannot be started) due to some abnormality, or some abnormality has occurred in the hydraulic system, etc. Even if a state is reached and time elapses in that state, oil can be supplied from the accumulator 5 to release the brake. Furthermore, even if it takes time to start the towing work, such as when the hydraulic machine (vehicle) stops due to some abnormality, it takes time for the towing vehicle to pull the hydraulic machine to arrive, the accumulator 5 It is possible to supply oil from the vehicle to release the brake, and thus the brake release state can be maintained for a long time.

Here, in the hydraulic brake release device according to the present embodiment, the traveling hydraulic machine is shifted from the parking brake state to the parking brake release state via the parking brake release preparation state. That is, the control unit 8 sets the check valve 3 to be disconnected before setting the supply control valve 4 to the connected state, but the parking brake release ready state is simultaneously performed with the check valve 3 and the supply control valve 4. This is because the switching operation of the check valve 3 may be delayed from the switching operation of the supply control valve 4 due to individual differences between the check valve 3 and the supply control valve 4 when the power is turned on.

That is, when the switching operation of the check valve 3 is delayed from the switching operation of the supply control valve 4, the brake release oil of the accumulator 5 is supplied not only to the brake cylinder X but also to the hydraulic tank 7 for a short time. Will be done. Such supply of the brake release oil to the hydraulic tank 7 causes a decrease in the pressure of the brake release oil, and the brake cylinder X cannot be completely driven, that is, the traveling hydraulic machine is completely released from the parking brake. It cannot be transferred to the state.

Therefore, considering the delay in the operation of the check valve 3 with respect to the supply control valve 4, it is preferable to go through the parking brake release ready state. However, if the operation delay of the check valve 3 with respect to the supply control valve 4 is extremely small, or if there is sufficient margin in the pressure and capacity of the accumulator 5, the parking brake release preparation state may be omitted.

Further, according to the hydraulic brake release device according to the present embodiment, when electricity cannot be supplied to each solenoid valve due to some abnormality, the brake state shown in FIG. 1 is caused by the elastic force of the spring of each solenoid valve. become. Therefore, according to this hydraulic brake release device, the hydraulic machine (vehicle) does not move freely, and therefore the safety is high.

FIG. 4 shows a parking brake release state when the engine of the traveling hydraulic machine is rotating, that is, when the hydraulic pump functions sufficiently as a supply pressure source. In this case, the control unit 8 connects the hydraulic pump to the brake cylinder X via the brake control valve 2 and the check valve 3 by applying a drive current only to the brake control valve 2. Therefore, the traveling hydraulic machine is put into the parking brake release state when the pressure oil supplied from the hydraulic pump acts on the brake cylinder X as the brake release oil.

Further, in the state of FIG. 4, oil can flow from the left side (hydraulic pump side) to the right side (accumulator 5 side) of the supply control valve 4, so that the pressure oil from the supply pressure source is also supplied to the accumulator 5. Accumulates. Then, the pressure oil accumulated in the accumulator 5 is supplied to the brake cylinder X as shown in FIG. 3, and the traveling hydraulic machine changes from the parking brake release preparation state to the parking brake release state.

Further, FIG. 5 shows a state (unloading state) in which the brake release oil is unloaded from the accumulator 5. When realizing this unload state, the control unit 8 applies a drive current only to the supply control valve 4 to supply the accumulator 5 to the hydraulic tank via the supply control valve 4, the check valve 3, and the brake control valve 2. Connect to 7. As a result, the brake release oil stored in the accumulator 5 is collected in the hydraulic tank 7 via the supply control valve 4, the check valve 3, and the brake control valve 2.

For example, in the case of maintenance of the hydraulic brake release device, if the accumulator 5 is in a state where the brake release oil is stored, the maintenance work is hindered. Therefore, in the hydraulic brake release device according to the present embodiment, even when the hydraulic pump cannot function as a supply pressure source due to the engine of the traveling hydraulic machine stopping, the supply control valve 4 is energized. , The brake release oil of the accumulator 5 can be collected in the hydraulic tank 7 to make the accumulator 5 substantially empty.

The present invention is not limited to the above embodiment, and for example, the following modifications can be considered.
(1) In the above embodiment, the check valve 3 is adopted as the first non-leak type solenoid valve, and the supply control valve 4 is adopted as the second non-leak type solenoid valve, but the present invention is not limited thereto. If it is a non-leak type solenoid valve that leaks less oil for releasing the brake than the conventional spool valve (2-position 3-port valve), another solenoid valve may be adopted.

(2) In the above embodiment, the brake cylinder X of the traveling hydraulic machine whose engine is stopped by remote operation is shifted from the parking brake state to the parking brake release state, but the present invention is not limited to this. In a state where the traveling hydraulic machine is operated by the driver's manual operation, for example, the driver may operate the brake release button provided on the driver's seat to input the parking brake release instruction to the control unit 8. ..

(3) In the above embodiment, a single accumulator 5 (accumulator) is provided, but a plurality of accumulators 5 may be provided in order to provide redundancy.

1 Filter 2 Brake control valve 3 Backflow prevention valve (1st non-leak type solenoid valve)
4 Supply control valve (second non-leak type solenoid valve)
5 Accumulator (accumulator)
6 Pressure gauge 7 Hydraulic tank 8 Control unit M1 1st manifold M2 2nd manifold

Claims (5)

The brake is provided with a brake control valve for switching between supply of brake release oil from the pressure supply source to the brake release cylinder and recovery of brake release oil from the brake release cylinder to the hydraulic tank, and the brake is pre-accumulated in the accumulator. A hydraulic brake release device that releases the brake by supplying release oil to the brake release cylinder.
A first non-leak type solenoid valve provided between the brake control valve and the brake release cylinder to switch connection / non-connection between the brake control valve and the brake release cylinder.
A connection / disconnection between the first non-leak type solenoid valve and the brake release cylinder and the accumulator is provided between the first non-leak type solenoid valve and the brake release cylinder and the accumulator. The second non-leak type solenoid valve to switch,
A hydraulic brake release device including a brake control valve, a control unit for controlling the first non-leakage solenoid valve and the second non-leakage solenoid valve by switching between energization and de-energization of a drive current. .. The control unit sets the brake release cylinder in the parking brake release state by setting the second non-leak type solenoid valve in the connected state and the first non-leak type solenoid valve in the non-connection state. The hydraulic brake release device according to claim 1, wherein the hydraulic brake is released. The hydraulic brake release according to claim 2, wherein the control unit sets the first non-leak type solenoid valve in the non-connection state before setting the second non-leak type solenoid valve in the connected state. apparatus. When the drive current is not energized, the brake control valve connects the first non-leak type solenoid valve and the hydraulic tank, and the first non-leakage solenoid valve is the brake control valve and the brake release cylinder. The second non-leak type solenoid valve is characterized in that the first non-leak type solenoid valve, the brake release cylinder, and the accumulator are not connected to each other. The hydraulic brake release device according to any one item. A traveling hydraulic machine that can be remotely controlled from the outside is provided, and the control unit is provided with the brake control valve, the first non-leak type solenoid valve, and the second non-leak based on a remote control command received from the outside. The hydraulic brake release device according to any one of claims 1 to 4, wherein the solenoid valve is controlled.

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