JP4672162B2 - Hydraulic unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an operating device including a hydraulic actuator operated by hydraulic pressure, and more particularly to a hydraulic unit suitable for being mounted on a vehicle.
[0002]
[Prior art]
This type of hydraulic unit is used to supply hydraulic fluid to a wing working part of a wing wheel, which is a kind of operating device, and a hydraulic pump and a hydraulic pump for sucking and discharging the hydraulic fluid into a tank storing the hydraulic fluid. A motor that drives the pressure pump to rotate is fixed, and a valve block that controls the flow direction of the hydraulic fluid that is discharged from the hydraulic pump and supplied to the hydraulic actuator and the flow direction of the hydraulic fluid that returns from the hydraulic actuator to the tank is located above the tank. It is located and attached to the side wall of the box, and the tank, hydraulic pump, electric motor, and valve block are accommodated inside the box. (For example, refer to JP-A-10-299645).
[0003]
[Problems to be solved by the invention]
However, in such a conventional hydraulic unit, pipes are respectively connected between the discharge port of the hydraulic pump and one internal inflow / outflow port of the valve block and between the other internal inflow / outflow port of the valve block and the tank. Connected and the pipe member occupies a part of the space that accommodates the tank, hydraulic pump, electric motor, and valve block inside the box, so piping connection by the pipe member is complicated and the inside of the box is occupied by the pipe member The space of the unit must be increased, and the entire unit becomes larger.
[0004]
The present invention provides a hydraulic unit that eliminates the need for pipe connection between the hydraulic pump and the valve block and between the valve block and the tank by a pipe member, simplifies the piping work, and can be made compact. The challenge is to do.
[0005]
[Means for Solving the Problems]
For this reason, in the present invention, the upper plate of the tank in which the working fluid is stored is composed of the first upper plate and the second upper plate, and the first upper plate has an opening penetrating the second upper plate. The opening is hermetically closed and detachably fixed to the first upper plate, and the second upper plate is connected to a hydraulic pump that sucks and discharges the hydraulic fluid stored in the tank and an electric motor that rotates the hydraulic pump. The member is mounted, the mounted mounting member is fixed to the second upper plate by the fixing member, and the hydraulic fluid discharged from the hydraulic pump to the mounting member and supplied to the hydraulic actuator and returned from the hydraulic actuator to the tank A valve block for switching and controlling the flow direction of the operating fluid is attached, and the hydraulic fluid supplied from the hydraulic pump to the hydraulic actuator is circulated by connecting the hydraulic pump and the valve block inside the mounting member. 1 channel and between valve block and tank A second flow path is formed through which hydraulic fluid that is connected and flows back to the tank from the hydraulic actuator is formed, and the fixing member is disposed at the opening side end of the second flow path to the tank. A connection flow path that constitutes a part of the second flow path is provided. In this case, an air breather that opens the inside of the tank to the atmosphere so as to suppress pressure fluctuations inside the tank accompanying fluctuations in the amount of hydraulic fluid stored in the tank is attached to the mounting member, and a third is connected between the air breather and the tank. A flow path is drilled inside the mounting member, and a fixing member for fixing the mounting member to the upper plate is disposed at an opening side end of the third flow path to the tank. It is desirable to provide a connection flow path that constitutes a part.
[0006]
According to the present invention, when the hydraulic pump is driven to rotate by the electric motor, the hydraulic pump sucks and discharges the hydraulic fluid stored in the tank, and the hydraulic fluid discharged from the hydraulic pump flows through the first flow path to the valve. The flow direction is switched and controlled by the block and supplied to the hydraulic actuator. The hydraulic fluid from the hydraulic actuator is controlled and switched by the valve block and flows through the second flow path and the connecting flow path of the fixed member to return to the tank. And actuating the hydraulic actuator. Since both the first flow path through which the hydraulic fluid discharged from the hydraulic pump flows and the second flow path through which the hydraulic fluid returning from the hydraulic actuator flows to the tank are formed inside the mounting member, the hydraulic pressure A pipe connection between the pump and the valve block and between the valve block and the tank can be made via an attachment member, and the attachment member for connecting the hydraulic pump and the electric motor has a pipe connection function. Piping connection between the pressure pump and the valve block and between the valve block and the tank with a pipe member can be eliminated, the piping work can be simplified, and the pipe member does not exist so that it is compact. Can be achieved.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1 to FIG. 4, reference numeral 1 denotes a tank in which a working fluid is stored. The tank is formed in a substantially square shape, and a liquid level gauge is provided on one side thereof so that the stored amount of working fluid can be visually recognized from the outside. A discharge plug 3 is detachably provided below the other side facing the side so that the stored hydraulic fluid can be discharged. Reference numeral 4 denotes an upper plate 4 of the tank 1, which includes a first upper plate 5 and a second upper plate 6. The first upper plate 5 is formed in a flat plate shape, and a substantially square opening 5A is partially penetrated, and a frame member 7 is erected along the periphery of the opening 5A. The seal member 8 whose vertical dimension is slightly higher than that of the frame member 7 is engaged. The second upper plate 6 has a flat plate shape larger than the opening 5A, and its edge is bent downward. The second upper plate 6 is placed on the seal member 8 to hermetically close the opening 5A, and the four bolt members 9A, 9B, 9C, 9D. And is detachably fixed to the first upper plate 5. An injection plug 10 is detachably attached to the first upper plate 5 and is provided so that it can be removed and injected into the tank 1.
[0008]
11 is a hydraulic pump that sucks and discharges the hydraulic fluid stored in the tank 1, and 12 is an electric motor that rotationally drives the hydraulic pump 11. Reference numeral 13 denotes a thick plate-like mounting member, which has a hydraulic pump 11 mounted on one side surface in the axial direction and a motor 12 mounted horizontally on the other side surface in the axial direction opposite to the one side surface. The drive shaft and the drive shaft of the electric motor 12 are connected by a coupling 14. The mounting member 13 is placed on the second upper plate 6 constituting the upper plate 4 and fixed to the second upper plate 6 by the fixing members 15 and 16, and the mounting member 13 is fixed to the second upper plate 6. A suction pipe 11A of the hydraulic pump 11 is provided so as to extend through the second upper plate 6 and into the stored hydraulic fluid of the tank 1 through the opening 5A. Reference numeral 17 denotes a manifold. The mounting surface 17A is in contact with the mounting side surface 13A orthogonal to the one side surface of the mounting member 13 to which the hydraulic pump 11 is mounted and the other side surface to which the electric motor 12 is mounted. ing. A relief valve 19 and an electromagnetic direction switching valve 20 are sequentially stacked on the upper surface of the manifold 17, and an electromagnetic direction switching valve 21 is attached to the lower surface, and two pipes are provided on the outer surface facing the mounting surface 17A. Two pipe joints 23A and 23B having built-in joints 22A and 22B and a flow rate adjusting valve project, and further four pilot operation check valves 24A, 24B, 24C and 24D are provided inside, and the pipe joint 22A, 23A is connected to one hydraulic cylinder 25A as a hydraulic actuator, and pipe joints 22B and 23B are connected to the other hydraulic cylinder 25B. More specifically, the pipe joints 22A and 22B are connected to the head side chambers 25E and 25F of the hydraulic cylinders 25A and 25B, respectively. The pipe joints 23A and 23B are connected to the cap side chambers 25C and 25D of the hydraulic cylinders 25A and 25B, respectively, and the working fluid is allowed to flow freely into the cap side chambers 25C and 25D with the built-in flow rate adjusting valves. The flow of hydraulic fluid from 25D is metered out. A valve block 25 for switching and controlling the flow direction of the hydraulic fluid discharged from the hydraulic pump 11 and supplied to the hydraulic cylinders 25A and 25B and the hydraulic fluid flowing back from the hydraulic cylinders 25A and 25B to the tank 1 is connected to the manifold 17. The electromagnetic direction switching valves 20 and 21 are configured.
[0009]
Inside the manifold 17, an inflow channel 26, an outflow channel 27, and four load channels 28A, 28B, 28C, 28D are formed. One end of each of the inflow channel 26 and the outflow channel 27 opens to the mounting surface 17A, and the other end branches to open on the upper surface and the lower surface. The load channel 28A has one end opened to the outer surface and connected to the pipe joint 22A, and the other end opened to the upper surface. The load channel 28B has one end opened to the outer surface and connected to the pipe joint 23A, and the other end opened to the upper surface. The load channel 28C has one end opened to the outer surface and connected to the pipe joint 22B, and the other end opened to the lower surface. The load channel 28D has one end opened to the outer surface and connected to the pipe joint 23B, and the other end opened to the lower surface. In addition, the pilot operation check valves 24A to 24D described above are disposed in the load flow paths 28A to 28D, and the pilot operation check valves 24A to 24D flow the hydraulic fluid to the hydraulic cylinders 25A and 25B in a free flow. At the same time, the flow of hydraulic fluid from the hydraulic cylinders 25A and 25B is blocked, the pilot operated check valve 24A is operated by the pilot pressure from the load flow path 28B, and the pilot operated check valve 24B is discharged from the load flow path 28A. Due to the action of the pilot pressure, the pilot operated check valve 24C is provided so as to be opened by the action of the pilot pressure from the load flow path 28D, and the pilot operated check valve 24D is provided by the action of the pilot pressure from the load flow path 28C. ing. The relief valve 19 moves up and down a flow path 19A connected to the inflow flow path 26, a flow path 19B connected to the outflow flow path 27, a flow path 19C connected to the load flow path 28A, and a flow path 19D connected to the load flow path 28B. It penetrates in the direction. The electromagnetic direction switching valve 20 is provided with flow paths 20A to 20D connected to the flow paths 19A to 19D of the relief valve 19, respectively, and the neutral position X that blocks the flow path 20A and communicates between the flow paths 20B, 20C, and 20D. A first switching position Y that switches the channel 20C to the channel 20B and switches the channel 20D to the channel 20A, and the channel 20C switches to the channel 20A and switches the channel 20D to the channel 20D. There are three positions, the second switching position Z that communicates with the switch 20B, and the three positions X to Z can be switched by energizing or de-energizing the solenoid. The electromagnetic direction switching valve 21 includes a flow path 21A connected to the inflow flow path 26, a flow path 21B connected to the outflow flow path 27, a flow path 21C connected to the load flow path 28C, and a flow path 21D connected to the load flow path 28D. The neutral position X1 that cuts through the flow path 21A and communicates between the flow paths 21B, 21C, and 21D, and switches the flow path 21C to the flow path 21B and switches the flow path 21D to the flow path 21A. There are three positions, the first switching position Y1, and the second switching position Z1 that switches the channel 21C to the channel 21A and switches the channel 21D to the channel 21B. Is provided so as to be switchable between the three positions X to Z.
[0010]
An air breather 29 is attached to the upper surface of the attachment member 13, and a first flow path 30, a second flow path 31, and a third flow path 32 are bored therein. One end of the first flow path 30 opens at the mounting side surface 13A, and connects between the discharge port of the hydraulic pump 11 and the inflow flow path 26 opened at the mounting surface 17A of the manifold 17 constituting the valve block 25. The hydraulic fluid supplied from the pressure pump 11 to the hydraulic cylinders 25A and 25B is circulated. The second flow path 31 has one end opened on the mounting side surface 13 </ b> A and the other end opened on the lower surface placed on the second upper plate 6 to be an opening side end to the tank 1. The fixing member 15 is threadedly engaged with the tip of the fixing member 15, and the fixing member 15 is provided with a connecting flow path 15 </ b> A that constitutes a part of the second flow path 31. The outflow passage 27 and the tank 1 are connected to each other, and the working fluid flowing back from the hydraulic cylinders 25A and 25B to the tank 1 is circulated. One end of the third flow path 32 is opened on the upper surface of the mounting member 13 and the air breather 29 is screwed onto the opening side end and the other end is opened on the lower surface placed on the second upper plate 6. The end of the fixing member 16 is screwed into the opening side end of the tank 1, and the fixing member 16 constitutes a part of the third flow path 32. The tank 1 is connected to the air breather 29 and the tank 1, and the tank 1 is opened to the atmosphere by the air breather 29 and stored in the tank 1. Suppresses pressure fluctuations.
[0011]
The fixing members 15 and 16 are inserted through holes 6A and 6B penetrating the second upper plate 6 from the lower surface side of the second upper plate 6 to the opening side ends of the second flow channel 31 and the third flow channel 32. By screwing into the respective portions, the root portion having a larger radial dimension than the holes 6 </ b> A and 6 </ b> B is brought into contact with the lower surface of the second upper plate 6, and the attachment member 13 is fixed to the second upper plate 6. The connection channel 15 </ b> A of the fixing member 15 includes a pipe 15 </ b> B whose tip is immersed in the storage hydraulic fluid of the tank 1. 33 is a reinforcing member that reinforces the mounting member 13 that is fixed to the second upper plate 6. The mounting member 13 is mounted on the second upper plate 6 and fixed to the second upper plate 6 by the bolt member 33A, and the mounting member is fixed by the bolt member 33B. It is attached to 13 roots. Reference numerals 34A and 34B denote mounting portions for mounting the hydraulic unit on the vehicle. Reference numeral 35 denotes an exterior cover formed by bending a plate-like member into a substantially U-shaped cross section and comprising a first side plate 35A, a second side plate 35B, and a back plate 35C. The hydraulic pump 11, the electric motor 12, and the mounting member 13 are provided. In addition, bolt members 36A and 36B are detachably attached to the tank 1 so as to cover the valve block 25 from three directions to form an accommodation space, and the pipe joints 22A, 22B, 23A, and 23B projecting from the manifold 17 attach the back plate 35C. It is provided through. A lid member (not shown) that closes the front and upper openings is detachably attached to the exterior cover 35.
[0012]
Next, the operation of this configuration will be described.
FIG. 1 shows a state in which the piston rods of the hydraulic cylinders 25A and 25B are stopped below, the electromagnetic direction switching valves 20 and 21 are located at neutral positions X and X1, and the pilot operated check valves 24A to 24D are hydraulic cylinders. The flow of hydraulic fluid from 25A and 25B is blocked.
[0013]
In this state, when the electromagnetic direction switching valve 20 is energized and switched to the first switching position Y, the hydraulic fluid discharged from the hydraulic pump 11 flows through the first flow path 30, the inflow flow path 26, and the flow paths 19A, 20A, 20D. 19D flows through the load flow path 28B, flows through the pilot check valve 24B and the fitting 23A in a free flow, and is supplied to the cap side chamber 25C of the hydraulic cylinder 25A. The hydraulic fluid in the head side chamber 25E of the hydraulic cylinder 25A Via the pilot operation check valve 24A opened by the action of the pilot pressure from the pipe joint 22A, the load flow path 28B, the load flow path 28A, the flow paths 19C, 20C, 20B, 19B, the outflow flow path 27, the second flow path The fluid flows through 31 and is returned to the tank 1, and the hydraulic cylinder 25A operates the piston rod upward in FIG. When the piston rod reaches the upper end, the electromagnetic direction switching valve 20 is deenergized to return to the neutral position X, and the operation of the hydraulic cylinder 25A is stopped.
[0014]
When the electromagnetic direction switching valve 20 is energized and switched to the second switching position Z while the piston rod of the hydraulic cylinder 25A is stopped at the upper end, the fluid is discharged from the hydraulic pump 11 and the first flow path 30, the inflow The hydraulic fluid flowing through the passage 26 and the flow passages 19A and 20A flows through the flow passages 20C and 19C and the load flow passage 28A, flows through the pilot check valve 24A in a free flow, and flows from the pipe joint 22A to the head side chamber of the hydraulic cylinder 25A. 25E, the hydraulic fluid in the cap side chamber 25C of the hydraulic cylinder 25A is meter-out controlled by the pipe joint 23A, and is opened by the action of the pilot pressure from the load flow path 28A. 28B, flow paths 19D, 20D, 20B, 19B, outflow flow path 27, second flow path 31 and return to tank 1, hydraulic cylinder 25A is a piston rod Actuated downward, the piston rod has reached the original position of FIG. 1, restores the directional control valve 20 to the neutral position X to the non-energized to stop the operation of the hydraulic cylinder 25A.
[0015]
In the state of FIG. 1, when the electromagnetic direction switching valve 21 is energized and switched to the first switching position Y1, the hydraulic fluid discharged from the hydraulic pump 11 and flowing through the first flow path 30 and the inflow flow path 26 flows through the flow path. 21A, 21D, load flow path 28D, pilot check valve 24D, pipe fitting 23B, and supplied to cap side chamber 25D of hydraulic cylinder 25B. The hydraulic fluid in head side chamber 25F of hydraulic cylinder 25B is supplied to pipe joint 22B, It returns to the tank 1 through the load flow path 28C, the flow paths 21C and 21B, the outflow flow path 27, and the second flow path 31 via the pilot operation check valve 24C opened by the action of the pilot pressure from the load flow path 28D. The hydraulic cylinder 25B operates the piston rod upward in FIG. 1, and when the piston rod reaches the upper end, the electromagnetic direction switching valve 21 is deenergized to return to the neutral position X1, and the hydraulic pressure To stop the operation of the Linda 25B.
[0016]
When the electromagnetic direction switching valve 21 is energized and switched to the second switching position Z1 in a state where the piston rod of the hydraulic cylinder 25B is stopped at the upper end, the fluid is discharged from the hydraulic pump 11 and flows from the first flow path 30. The hydraulic fluid flowing through 21A flows through the flow path 21C, the load flow path 28C, and the pilot operation check valve 24C, and is supplied from the pipe joint 22B to the head side chamber 25F of the hydraulic cylinder 25B, and in the cap side chamber 25D of the hydraulic cylinder 25B. The hydraulic fluid is meter-out controlled by the pipe joint 23B and is opened by the action of the pilot pressure from the load passage 28C. The pilot operation check valve 24D, the load passage 28D, the passages 21D and 21B, the outflow passage 27, 2 flows through the flow path 31 and is returned to the tank 1, and the hydraulic cylinder 25B operates the piston rod downward, and when the piston rod reaches the original position in FIG. The magnetic directional control valve 21 in the non-energized to return to the neutral position X1, and stops the operation of the hydraulic cylinder 25B.
[0017]
In the state of FIG. 1, it is also possible to simultaneously operate the piston rods of the hydraulic cylinders 25A and 25B by switching both the electromagnetic direction switching valves 20 and 21 to the first switching positions Y and Y1. . As the hydraulic cylinders 25A and 25B are operated, the amount of hydraulic fluid stored in the tank 1 varies by the amount corresponding to the volume of the piston rod when the piston rod is positioned downward and when the piston rod is positioned upward. However, since the inside of the tank 1 is opened to the atmosphere from the third flow path 32 via the air breather 29, the pressure fluctuation in the tank 1 accompanying the fluctuation of the amount of hydraulic fluid stored in the tank 1 can be suppressed.
[0018]
With this operation, both the first flow path 30 through which the hydraulic fluid discharged from the hydraulic pump 11 flows and the second flow path 31 through which the hydraulic fluid returning to the tank 1 flows from the hydraulic cylinders 25 </ b> A and 25 </ b> B are inside the mounting member 13. Therefore, the hydraulic pump 11 and the valve block 25 and the valve block 25 and the tank 1 can be connected to each other through the mounting member 13, and the hydraulic pump 11 and the electric motor 12 are connected. Since the mounting member 13 has a piping connection function, it is unnecessary to connect the piping between the hydraulic pump and the valve block and between the valve block and the tank by a pipe member as in the prior art. Simplification can be achieved, and compactness can be achieved by the absence of the pipe member. Further, a fixing member 15 having a connection flow path 15 </ b> A that constitutes a part of the second flow path 31 is disposed at an opening side end portion of the second flow path 31 formed in the attachment member 13 to the tank 1. Thus, since the attachment member 13 is fixed to the second upper plate 6 constituting the upper plate 4, the hydraulic cylinders 25 </ b> A and 25 </ b> B are attached as the attachment member 13 is fixed to the second upper plate 6 by the fixing member 15. A function of a flow path for circulating the working fluid returning to the tank 1 can be provided, and a flow path for circulating the working fluid returning from the hydraulic cylinders 25A and 25B to the tank 1 is attached separately from the place where the fixing member 15 is disposed. Compared with the case where it is provided on the member 13, the mounting member 13 can be reduced in size and the configuration can be simplified. Furthermore, the connection which comprises a part of 3rd flow path 32 in the opening side edge part to the tank 1 of the 3rd flow path 32 which connects between the air breather 29 attached to the upper surface of the attachment member 13, and the tank 1. FIG. Since the mounting member 13 is fixed to the second upper plate 6 by disposing the fixing member 16 having the flow path 16A, the fixing member 16 is fixed to the second upper plate 6 by the fixing member 16. A function of opening the inside of the tank 1 to the atmosphere via the air breather 32 can be provided, and a case in which a flow path for opening the inside of the tank 1 to the atmosphere via the air breather 32 is provided in the mounting member 13 separately from the location of the fixing member 16. In comparison, the mounting member 13 can be further miniaturized and the configuration can be further simplified. Furthermore, the upper plate 4 is composed of a first upper plate 5 penetrating a substantially rectangular opening 5A, and a second upper plate 6 sealingly closing the opening 5A of the first upper plate 5, and the second upper plate. Since the mounting member 13 is fixed to 6, the second upper plate 6 has a small shape that seals and closes the opening 5 </ b> A of the first upper plate 5 compared to the case where the mounting member 13 is fixed to a single upper plate. It is easy to handle, and it is possible to easily perform the work when fixing the attachment member 13 to the second upper plate 6 by the fixing members 15 and 16.
[0019]
Incidentally, the two hydraulic cylinders 25A in one embodiment, 25B of the flow direction in order to respectively change-over control, but using two directional control valve 20 and 21 constituting the valve block 25, the application Of course, the number of electromagnetic directional control valves may be increased or decreased accordingly.
[0020]
【The invention's effect】
As described above, in the first aspect of the present invention, both the first flow path through which the hydraulic fluid discharged from the hydraulic pump flows and the second flow path through which the hydraulic fluid returning from the hydraulic actuator flows to the tank are located inside the mounting member. Since it is drilled, piping connection between the hydraulic pump and the valve block and between the valve block and the tank can be made via an attachment member, and the piping connection function can be connected to the attachment member that connects the hydraulic pump and the electric motor. Therefore, it is unnecessary to connect pipes between the hydraulic pump and the valve block and between the valve block and the tank by a pipe member as in the prior art, and the piping work can be simplified. Compactness can be achieved by the absence of the pipe member. In addition, a fixing member having a connection flow path that constitutes a part of the second flow path is disposed at an opening side end portion of the second flow path formed in the mounting member to the tank. Since it is fixed to the second upper plate , it can be provided with a function of a flow path for circulating the working fluid that recirculates from the hydraulic actuator to the tank when the mounting member is fixed to the second upper plate by the fixing member. Compared to the case where a flow path for flowing hydraulic fluid flowing back from the pressure actuator to the tank is provided in the mounting member separately from the location of the fixing member, the mounting member can be reduced in size and the configuration can be simplified. Can do. Furthermore, the upper plate is composed of a first upper plate having an opening formed therein, and a second upper plate that seals and closes the opening of the first upper plate, and the mounting member is fixed to the second upper plate. Compared to the case where the mounting member is fixed to a single upper plate, the second upper plate may be a small shape that seals and closes the opening of the first upper plate and is easy to handle. It is possible to easily perform the work for fixing to the plate.
[0021]
In addition, in the invention according to claim 2, in addition to the effect of the invention according to claim 1, the opening side end to the tank of the third flow path connecting the air breather attached to the attachment member and the tank has the first Since the mounting member is fixed to the upper plate by disposing the fixing member having the connection flow channel that constitutes a part of the three flow channels, the tank is attached to the upper plate by the fixing member. A function to open the inside to the atmosphere via an air breather can be provided, and the mounting member is smaller than the case where a flow path that opens the inside of the tank to the atmosphere via an air breather is provided separately from the location of the fixing member. And the configuration can be further simplified.
[Brief description of the drawings]
FIG. 1 is a hydraulic circuit diagram of a hydraulic unit showing an embodiment of the present invention.
FIG. 2 is a front view of an embodiment.
FIG. 3 is a plan view of one embodiment.
4 is an enlarged sectional view taken along line AA in FIG. 3. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tank 4 Upper plate 11 Hydraulic pump 12 Electric motor 13 Mounting member 15, 16 Fixed member 15A, 16A Connection flow path 25A, 25B Hydraulic cylinder (hydraulic actuator)
29 Air breather 30 1st flow path 31 2nd flow path

Claims (2)

The upper plate of the tank storing the working fluid is composed of a first upper plate and a second upper plate. An opening is formed through the first upper plate, and the second upper plate seals and closes the opening. A mounting member is mounted on the second upper plate, which is detachably fixed to the upper plate, and is connected to a hydraulic pump that sucks and discharges the hydraulic fluid stored in the tank and an electric motor that rotationally drives the hydraulic pump. The mounted mounting member is fixed to the second upper plate by a fixing member, and the flow direction of the hydraulic fluid discharged from the hydraulic pump and supplied to the hydraulic actuator to the mounting member and the flow direction of the hydraulic fluid returned from the hydraulic actuator to the tank A valve block for switching control is mounted, and a first flow path and a valve block for connecting hydraulic fluid to the hydraulic actuator from the hydraulic pump by connecting between the hydraulic pump and the valve block inside the mounting member Connect the tank to the hydraulic actuator A second flow path through which the working fluid that circulates from the tank to the tank is drilled, and the fixing member is disposed at an opening side end of the second flow path to the tank. A hydraulic unit comprising a connection flow path that constitutes a part of the hydraulic pressure unit.   An air breather that opens the inside of the tank to the atmosphere so as to suppress pressure fluctuations inside the tank accompanying fluctuations in the amount of hydraulic fluid stored in the tank is attached to the mounting member, and a third flow path that connects the air breather and the tank is provided. A fixing member is provided inside the mounting member, and a fixing member for fixing the mounting member to the upper plate is disposed at an opening side end portion of the third flow channel to the tank. The hydraulic unit according to claim 1, further comprising a connecting flow path.

Images