JPH09210003A - Divided type hydraulic unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a piping space and improve workability of disassembling and assembling work by reducing the number of hydraulic hoses for connecting the units with each other in a hydraulic unit where a hydraulic power unit and a control unit are divided. SOLUTION: The return pipes 55, 34 of respective units 2, 3 are connected with each other through a low pressure hose 39 and open type connecting hardware 38, 37 with no self-sealing function. The midway part of the return pipe 34 on control unit 3 side is formed into a reversed-U type pipe 58, and on a branch pipe 59 installed on its top, a cock 35 and an air breather 36 are fitted. At the time of disassembling, a cock 35 on the control unit 3 side and a cock 43 on the hydraulic power unit 2 are opened to suck the hydraulic oil in the low pressure hose 39 into an oil tank 4 with a hydraulic pump 4T. At the time of assembling, the cocks 35, 43, 44 are opened to fill the inside of low pressure hose 39 with hydraulic oil from the oil tank 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic unit used in industrial machinery, construction machinery, etc., and more particularly to a hydraulic unit having a structure in which it is divided into several units in consideration of transportation and usage.

[0002]

2. Description of the Related Art A hydraulic unit in an industrial machine or a construction machine drives a hydraulic pump by an engine or an electric motor to forcibly suck up the hydraulic oil in an oil tank and discharge it as pressure oil to bring the pressure oil to a desired pressure. The pressure oil is controlled and sent to a target actuator outside the hydraulic unit by using a direction switching valve or the like, and the oil that has finished its work is returned to the oil tank. In such a hydraulic unit, generally, hydraulic equipment such as the hydraulic pump, the oil tank, the pressure control valve, the directional control valve and the like as described above are mounted on the base frame and are usually combined into one hydraulic unit.

However, at times, it is divided into a hydraulic power unit having a function of simply sending out pressure oil and a control unit for controlling the discharged pressure oil by various control valves according to the application and sending the pressure oil to each actuator. May be That is, if the control unit is adapted to the intended use, the hydraulic power unit can be commonly used, and the hydraulic power unit has the advantage of being versatile. Further, if the hydraulic power unit and the control unit are separated, there is an advantage that they can be divided and transported by a small truck.

[0004]

As described above, when the hydraulic power unit and the control unit are divided and connected by the hydraulic hose, processing of the hydraulic hose becomes a problem. As a hydraulic hose connecting the hydraulic power unit and the control unit, it is necessary to provide as many high-pressure hoses as the number of hydraulic pumps, but it is not necessary to provide a low-pressure hose for sending return oil for each actuator. Want to reduce the number.

However, if the number of low pressure hoses for the return pipe is reduced, the size of the hose becomes large. If the size becomes large, there is no self-sealing type quick joint on the market, so if you use open type connection fittings that do not have a self-sealing function to connect the return piping of each hydraulic unit, both units should be disassembled and assembled. It is difficult to treat the hydraulic oil in the hose to be connected, and there are cases where the hydraulic oil spills around. Further, when air enters the hose and is connected for operation, a large amount of air in the pipe may cause cavitation, which may cause damage to the hydraulic pump or the like depending on the situation.

Therefore, the quick joint is divided into hoses of a size that can be used. As a result, the number of hoses is increased, the piping space in the hydraulic unit is increased, and the disassembly and assembly workability is increased. However, there was a problem that this would lead to deterioration.

In view of the above-mentioned problems, the present invention is a hydraulic unit in which a hydraulic power unit and a control unit are divided and each unit is connected by a hydraulic hose, and the number of hydraulic hoses is reduced to reduce piping space. The workability of the hydraulic hose can be reduced and the workability of assembling and assembling is improved. It is an object of the present invention to provide a split type hydraulic unit having a structure capable of removing air and thus suppressing the occurrence of cavitation when a hydraulic pump is driven.

[0008]

In order to achieve the above object, the invention of claim 1 includes a hydraulic power unit having a hydraulic pump and a hydraulic oil tank, and a control unit for distributing pressure oil to each actuator. In a split type hydraulic unit that is connected by a removable hydraulic hose, an open type fitting without a self-sealing function is provided at the connection part of the low pressure hose that connects the return pipes of each unit, and the return pipe of the control unit side An inverted U-shaped pipe is provided midway, a branch pipe is provided on the top of the inverted U-shaped pipe, and a cock is provided at the branch pipe or the root thereof, and the air in the pipe is discharged to the outside through the cock or inside the pipe. Install an air breather at a position higher than the oil level of the oil tank of the hydraulic power unit, and connect the open type connection fitting on the hydraulic power unit side with the oil breather. A check valve that prevents the backflow of hydraulic oil from the oil tank is provided in the middle of the pipe between the oil tank and the tank, and the pipe that has the check valve between the open type connection fitting on the hydraulic power unit side and the oil tank is A separate branch pipe is provided, and a hydraulic pump for sucking the hydraulic oil for sucking the hydraulic oil in the low pressure hose into the oil tank is provided in the branch pipe, and the low pressure hose is used for the hydraulic power unit when the unit is disassembled. It is characterized in that a cock is provided for communicating with the pump and for communicating the inside of the oil tank with the low pressure hose when the hydraulic unit is assembled.

The invention of claim 2 is characterized in that the cock on the side of the control unit is mounted so as to be substantially at the same height as the oil level of the hydraulic oil in the oil tank of the hydraulic power unit.

According to a third aspect of the present invention, instead of using the inverted U-shaped pipe in the middle of the return pipe on the control unit side, or in addition to the inverted U-shaped pipe, the return pipe is actuated when the hydraulic unit is in operation. It is characterized in that a pilot check valve that is opened by the pressure on the discharge side of the hydraulic pump is installed.

[0011]

According to the first aspect of the present invention, when the operation of the hydraulic unit is stopped and the hydraulic power unit and the control unit are disassembled for transportation or the like, the cock provided in the branch pipe section of the control unit is operated to operate the low pressure hose. Is communicated with the outside air and the cock provided in the hydraulic power unit is operated to communicate the low pressure hose with the hydraulic pump for sucking hydraulic oil to drive the hydraulic pump, whereby the hydraulic oil in the low pressure hose is transferred to the oil tank. Inhale. At this time, reverse U
Since the V-shaped pipe is provided, air does not enter the directional control valve in the control unit.

On the other hand, when connecting the hydraulic power unit and the control unit via the hydraulic hose, the cock provided in the branch pipe is operated to connect the low pressure hose to the outside air, and the oil tank and the low pressure hose are hydraulically connected. Operate the cock in the power unit to establish communication and fill the low pressure hose with hydraulic oil from the oil tank. After that, at the time of work, shut off the outside air by operating the cock of the control unit, and shut off the circuit through the cock of the low pressure hose and the hydraulic oil suction hydraulic pump and the oil tank to shut off the actuator driving hydraulic pump in the hydraulic power unit. It is activated and the return oil is returned to the oil tank via the check valve.

According to the second aspect of the present invention, the position of the cock provided on the branch pipe portion is substantially the same as the height of the oil surface of the oil tank. Therefore, when the hydraulic oil is returned to the low pressure hose, the cock position is automatically set. The hydraulic oil is full.

In the third aspect of the present invention, since the pilot check valve is provided in the return pipe of the control unit, when the low pressure hose is filled with air when the hydraulic power unit and the control unit are separated, a directional control valve or the like in the control unit is provided. The invasion of air into the space is prevented.

[0015]

1 is a block diagram showing an embodiment of a split type hydraulic unit according to the present invention, in which each device for sucking or filling hydraulic oil in a low pressure hose which is a part of a return pipe is shown. It shows the installation status. FIG. 2 is a hydraulic circuit diagram showing the overall configuration of this embodiment.

In FIG. 2, the split hydraulic unit 1 is
It is composed of a hydraulic power unit 2 and a control unit 3. In the hydraulic power unit 2, 4 is an oil tank equipped with a filler port 6 and an air breather 5, 7 and 8 are strainers, 9 and 10 are hydraulic pumps driven by motors 11 and 12, 13 and 14 are pressure control valves, and 53. Is a check valve provided in these secondary side pipes.

The discharge pipes of the hydraulic pumps 9 and 10 are attached to and removed from the direction switching valves 22 and 23 of the control unit 3 via the quick joints 15 and 17, respectively, and the quick joints 16 and 1.
It is connected via a high-pressure hose 21 which is detachable via 8 The secondary side pipes of the direction switching valves 22 and 23 are high pressure hoses 30 and 31 and quick joints 26 that are attached to and detached from actuators such as a hydraulic motor 29 and a hydraulic cylinder 28 via quick joints 24 and 25, respectively. A high-pressure hose 32 that is attached and detached via 27,
Connected by 33.

Reference numerals 34 and 55 are return pipes that are integrated into one on the control unit 3 side and the hydraulic power unit 2 side, respectively, and 39 is a low pressure hose that connects these return pipes 34 and 55 to each other. Open type connection fittings 3 with no self-sealing function on both ends
It is detachably connected to the return pipes 34, 55 via 7, 38. The return pipe 55 on the hydraulic power unit 2 side is provided with a cooler 40, a filter 41, and a check valve 42.

Reference numeral 50 denotes a drain pipe of the hydraulic motor 29, and 51
Is a drain hose, 19 is a quick joint that detachably connects the drain hose 51 to the hydraulic power unit 2, and 52 is a check valve provided in the hydraulic power unit side drain pipe.

The above-mentioned components are used in the normal operation of the hydraulic unit.
The configuration for disassembling the hydraulic unit, removing oil during assembly, and filling oil will be described. First, the hydraulic power unit 2 side will be described. Reference numeral 56 denotes a pipe provided between the connection fitting 38 and the oil tank 4 so as to be branched from the return pipe 55. The branch pipe 56 is operated when the hydraulic unit is disassembled. A hydraulic pump 47 for sucking hydraulic oil in a low-pressure hose 39 driven by a motor 48 and filters 45, 4 before and after the hydraulic pump 47.
6 and a check valve 49, and a suction side pipe 56a of the hydraulic pump 47 which is a part of the branch pipe 56.
Is provided with a cock 43. The pipe 57 and the cock 44 provided in the pipe 57 are provided to fill the low pressure hose 39 with hydraulic oil when the units are connected, and one end of the pipe 57 is located below the oil level of the oil tank 4. The other end is connected between the cock 43 and the hydraulic pump 47 in the suction side pipe 56a.

On the control unit 3 side, an inverted U-shaped pipe 58 forming a part of the return pipe 34 is provided.
As shown in FIG. 2, the branch pipe 5 is provided on the top of the inverted U-shaped pipe 58.
9 is provided, the branch pipe 59 is provided with a cock 35, and an air breather 36 for discharging the air in the pipe to the outside through the cock 35 or taking it into the pipe is higher than the oil level of the oil tank 4 of the hydraulic power unit 2. Provide at the position. The cock 35 may be a three-way cock provided at the base of the branch pipe 59. In this case, the three-way cock is the return pipe 34.
May have a switching position for communicating the low pressure hose 39 with the low pressure hose 39 and a switching position for communicating the low pressure hose 39 with the outside air.

As shown in FIG. 1, the oil tank 4 is located above the hydraulic power unit 2, and the cocks 43 and 44 are located below the oil tank 4. Further, the open type connecting fitting 38 of the low pressure hose 39 forming the return pipe is provided below the hydraulic power unit 2, while the open connecting fitting 37 on the control unit 3 side is located above the control unit 3. The cock 35 and the air breather 36 are arranged in the vicinity of the connection fitting 37, so that the air accumulated at the top of the inverted U-shaped pipe 58 is easily discharged to the outside. The height of the cock 35 is set to substantially match the height of the oil surface of the oil tank 4 of the hydraulic power unit 2.

Next, the operation of this embodiment will be described. During normal operation of this hydraulic unit, the cocks 35, 43,
44 is closed and the hydraulic pump 47 is stopped. Then, by operating the hydraulic pumps 9 and 10, the hydraulic oil in the oil tank 4 is sucked up and discharged. The pressure oil discharged is the high pressure hose 20,
It is sent to the respective directional control valves 22 and 23 via 21. Then, after actuating the hydraulic motor 29 and the hydraulic cylinder 28 which are actuators corresponding to the directional control valves 22 and 23, the return oil is sent to the directional control valves 22 and 23 again, and the return pipe 34 and the inverted U-shaped pipe. After passing through 58, it returns to the oil tank 4 via the connection fitting 37, the low pressure hose 39, the connection fitting 38, the cooler 40 of the return pipe 55, the filter 41, and the check valve 42. In FIG. 1, solid arrows indicate the flow of hydraulic oil when the hydraulic unit 1 is operating.

Next, the case where the hydraulic power unit 2 and the control unit 3 are disassembled will be described. In this case, stop driving the hydraulic pumps 9 and 10 and turn off the high pressure hose 2.
Remove 0 and 21 from the quick joints 15-18. Also, connect the drain hose 51 to the quick joint 19
Remove from Then, the cocks 35 and 43 are opened and the cock 44 is kept closed. In this way, when the hydraulic pumps 9 and 10 are stopped, the cock 35
Since the air breather 36 is located at a position higher than the oil level of the oil tank 4 even when it is opened, the hydraulic oil does not leak outside.

As described above, the cocks 35, 43 and 44 are operated to operate the hydraulic pump 47. As a result, air enters from the air breather 36, and the working oil in the low pressure hose 39 is sucked through the path indicated by the dotted arrow and returned to the oil tank 4. At this time, the cock 44 is closed and the return pipe 55 is closed.
Is provided with a check valve 42, and since the inverted U-shaped pipe 58 sucks only the hydraulic oil at the top by the hydraulic pump 47, only the hydraulic oil in the pipeline divided by these is transferred to the oil tank 4. It will be sucked in and eventually the inside of the pipe will be filled with air. Therefore, when the low pressure hose 39 is removed, the hydraulic oil does not flow out. Further, since check valves 49 and 42 are provided in the discharge side pipe and the return pipe 55 of the hydraulic pump 47, even if the hydraulic pump 47 is stopped, the hydraulic pump 47 is stopped.
The hydraulic oil in the discharge side pipe or the oil tank 4 does not flow out to the low pressure hose 39 side.

Next, the case where the hydraulic power unit 2 and the control unit 3 are connected will be described. First, the high pressure hoses 20 and 21 and the drain hose 51 are connected through the quick joints 15 to 19. Then, the low pressure hose 39 is connected via the connection fittings 37 and 38.
Then, the cocks 35, 43 and 44 are opened. As a result, the hydraulic oil in the oil tank 4 is changed to the cock 4 as shown by the alternate long and short dash line.
The low-pressure hose 39 is filled via 4 and 43. here,
As shown in FIG. 1, since the height of the cock 35 is set to be substantially the same as the height of the oil surface of the oil tank 4, the air in the low pressure hose 39 is automatically pushed out by the hydraulic oil by the siphon principle. Is discharged to the outside through the air breather 36. As a result, the return pipe 55, the low pressure hose 39, the reverse U
The inside of the V-shaped pipe 58 is filled with hydraulic oil. And cook 3
5, 43 are closed, and the operation state is set.

Since the oil level of the hydraulic oil in the oil tank 4 is not constant depending on the operating condition of the actuator, the inverted U-shaped pipe 58 is not always filled with the hydraulic oil, but air may remain. The air is melted into the hydraulic oil at the stage of starting the operation, and the air is discharged into the oil tank 4 in the process of circulation.

FIGS. 3 and 4 are a structural view and a hydraulic circuit diagram showing another embodiment of the present invention drawn corresponding to FIGS. 1 and 2, respectively. In this embodiment, the return pipe of the control unit 3 is shown. 34, a pilot check valve 54 that is opened by pressure oil from the hydraulic pump 9 or 10 via a pilot pipe 62 is provided.

According to this embodiment, the inverted U-shaped pipe 58 is provided.
Even if a horizontal pipe is provided as shown by the pipe 60 in FIG. 3 without providing the valve, when the cock 35 located at the height of the oil level in the oil tank 4 is opened and the air in the low pressure hose 39 is sucked by the hydraulic pump 47. The pilot check valve 54 prevents air from entering the directional switching valves 22 and 23 side of the return pipe 34 from the pilot check valve 54. Further, according to the present embodiment, the branch pipe 61 having the cock 35 and the air breather 36 for sucking in or removing the air may be thin. Moreover, the upper piping structure in the control unit 3 is simplified. Further, the inverted U-shaped pipe 58 shown in FIG. 1 may be provided with a pilot check valve 54 as shown by a chain double-dashed line.

In this embodiment, the pipe 57 having the cock 44 that opens when the hydraulic unit is connected is connected to the suction side pipe 56a between the connection fitting 38 and the cock 43 (connects to the return pipe 55). The pipe 5
One end of 7 may be connected between the cock 43 and the hydraulic pump 47. If the pipe 57 is connected between the cock 43 and the connection fitting 38 as in this embodiment, the cock 43 does not necessarily need to be opened when the hydraulic unit is connected. However, in the embodiment shown in FIGS. 1 and 2, when the cock 44 is opened with the cock 43 closed and the hydraulic pump 47 is operated, the filters 45 attached to the front and rear of the hydraulic pump 47,
The effect of 46 is that the hydraulic oil in the oil tank 4 can be filtered and washed. The pilot check valve 54 may be opened by a hydraulic pump that operates when the hydraulic unit 1 is in operation, and if a pilot pump is provided, it may be opened by oil discharged from the pilot pump. Also,
The cocks 43 and 44 are three-way cocks provided at the connecting portion between the suction side pipe 56a and the pipe 57, and the three-way cocks have a switching position for connecting the low pressure hose 39 and the hydraulic oil suction hydraulic pump 47 to each other and a low pressure hose 39. And a switching position for communicating the oil tank 4 with each other, and a switching position for communicating the oil tank 4 with the hydraulic pump 47 are selected.

In the above embodiment, one low pressure hose 39 is provided. However, when the number of actuators is large, a plurality of low pressure hoses 39 may be provided.

[0032]

According to the first aspect of the present invention, in the split type hydraulic unit, even if open type connecting fittings are used at both ends of the low pressure hose connecting the hydraulic power unit and the control unit, when the hydraulic unit is disassembled Since the hydraulic oil can be sucked into the oil tank, the hydraulic oil does not flow out when the low pressure hose is removed. Further, when connecting the units, a low pressure hose filled with air is connected. However, the air in the low pressure hose can be released to the outside and the working oil can be filled by simply opening the cock. For this reason, it is possible to suppress the occurrence of cavitation when the hydraulic pump for driving the actuator is driven.

Also, since a large-diameter low-pressure hose with an open connection fitting can be used, the low-pressure hoses can be combined into a small number such as one, and as a result, the hydraulic pressure between the hydraulic power unit and the control unit can be reduced. The number of hoses can be reduced, and the piping space can be reduced and the workability of disassembly and assembly can be improved.

According to the second aspect of the present invention, the cock on the control unit side is mounted so as to be substantially at the same level as the oil surface of the hydraulic oil in the oil tank of the hydraulic power unit. It can be filled up to the right and left, and air can be prevented from entering the circulation circuit of the hydraulic oil.

According to the third aspect, instead of the reverse U-shaped pipe in the middle of the return pipe on the control unit side, or in addition to the reverse U-shaped pipe, the return pipe on the discharge side of the hydraulic pump is connected to the return pipe. Since a pilot check valve that opens by pressure is provided, when filling the low pressure hose with air when separating the hydraulic power unit and the control unit,
Air is prevented from entering the directional control valve in the control unit by the pilot check valve. Further, when the pipe between the pilot check valve and the open connection fitting is installed horizontally, the branch pipe can be made thin and the upper pipe structure of the control unit becomes simple.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a split hydraulic unit according to the present invention, showing a mounting state of each device for draining or filling hydraulic oil in a low pressure hose of a return pipe.

FIG. 2 is a hydraulic circuit diagram showing the overall configuration of the embodiment.

FIG. 3 is a view, corresponding to FIG. 1, of another embodiment of the split hydraulic unit according to the present invention.

FIG. 4 is a view corresponding to FIG. 2 of the embodiment of FIG.

[Explanation of symbols]

1: hydraulic unit, 2: hydraulic power unit, 3: control unit, 4: oil tank, 5, 36: air breather, 6: lubrication port, 7, 8, 41, 45, 46: filter, 9, 10: hydraulic pump , 11, 12: motor, 1
3, 14: Pressure control valve, 15-19, 24-27: Quick joint, 20, 21, 30-33: High pressure hose, 22, 23: Direction switching valve, 28: Hydraulic cylinder, 2
9: Hydraulic motor, 34, 55: Return piping, 35, 43,
44: Cock, 37, 38: Open type connection fitting, 39: Low pressure hose, 42, 49, 52, 53: Check valve, 4
7: Hydraulic pump for sucking hydraulic oil in low pressure hose, 54: Pilot check valve, 56: Branch pipe, 56a: Suction side pipe, 58: Inverted U-shaped pipe, 59, 61: Branch pipe

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[Procedure amendment]

[Submission date] June 29, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

Claims (3)

[Claims] 1. A split type hydraulic unit in which a hydraulic power unit having a hydraulic pump and a hydraulic oil tank, and a control unit for distributing pressure oil to each actuator are connected by a removable hydraulic hose. An open type connection fitting without a self-sealing function is provided at the connection part of the low pressure hose that connects the return pipes of the unit, and the middle of the return pipe on the control unit side is made into an inverted U-shaped pipe, and at the top of the inverted U-shaped pipe. A branch pipe is provided, and a cock is provided at the branch pipe or its root, and an air breather for discharging the air in the pipe to the outside or taking it into the pipe through the cock is located at a position higher than the oil level of the oil tank of the hydraulic power unit. To prevent backflow of hydraulic oil from the oil tank in the middle of the pipe between the open type connection fitting on the hydraulic power unit side and the oil tank. A check valve for stopping is provided, and a branch pipe different from the pipe having the check valve is provided between the open type connection fitting on the hydraulic power unit side and the oil tank, and the hydraulic oil in the low pressure hose is provided in the branch pipe. A hydraulic pump for sucking hydraulic oil into the oil tank is provided, the low pressure hose is connected to the hydraulic power unit when the unit is disassembled, and the hydraulic pump is connected to the low pressure hose when the hydraulic unit is assembled. Split hydraulic unit characterized by having a cock. 2. The split hydraulic unit according to claim 1, wherein the cock on the control unit side is mounted so as to be substantially at the same height as the oil level of the hydraulic oil in the oil tank of the hydraulic power unit. 3. The hydraulic unit according to claim 1 or 2, in place of the inverted U-shaped pipe in the middle of the return pipe on the control unit side, or in addition to the inverted U-shaped pipe. A split-type hydraulic unit, which is provided with a pilot check valve that opens depending on the pressure on the discharge side of a hydraulic pump that operates from time to time.