JPH0740696Y2 - Hydraulic pump device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a hydraulic pump device used for a vehicle suspension mechanism having a vehicle height adjusting function, for example.

[Prior art]

This type of vehicle suspension mechanism having a vehicle height adjustment function connects the oil chamber in the cylinder housing with an external hydraulic unit through a pipe, and drives this hydraulic unit to move oil in and out of the oil chamber. The height of the vehicle is raised and lowered by adjusting the amount of protrusion of the piston rod with respect to the cylinder housing.

By the way, the conventional hydraulic unit includes a plunger-type hydraulic pump driven by a DC motor. This hydraulic pump sucks and pressurizes the oil by the reciprocating motion of the plunger, and sends the pressurized oil to the above pipe through the discharge port.At this discharge port, a check valve for preventing the reverse flow of oil is provided. It has been incorporated.

[Problems to be solved by the invention]

However, in this plunger type hydraulic pump, the hydraulic pressure applied to the discharge port fluctuates every time the plunger reciprocates, and the check valve repeatedly opens and closes, so that pulsation occurs downstream of the check valve. Therefore, there is a problem that the discharge flow rate and the discharge pressure in the pipe largely fluctuate, and the pipe vibrates to cause noise.

As a measure against noise due to this pulsation, it is conceivable to arrange a pressure accumulator in the middle of the pipe, but if this is done, the pipe and joint etc. are required starting with the pressure accumulator, so the pipe becomes complicated or However, there was a problem that it required a large space for installation, and there was room for improvement in practical use.

Further, as in the electromagnetic pump described in JP-A-59-18283, there is one in which a hollow pulsation absorber is housed in the fluid passage chamber formed between the suction port and the discharge port. Since the absorber is just a bag that easily collapses when the oil pressure is high, it has an extremely high pressure (50 to 10
It is practically impossible to apply to a hydraulic system that produces 0 kg / cm ² or more). Further, as in the hydraulic pump described in JP-A-60-222570, a piston for pressure change restriction is provided at a place communicating with the chamber, and this piston is biased by a coil spring housed in a bellows tube. In the case of this known example as well, the tube is crushed in the radial direction when a high hydraulic pressure acts from the outer peripheral side of the bellows tube.

The present invention was made based on such circumstances,
It is an object of the present invention to provide a hydraulic pump device which is capable of preventing vibration of the pipe, does not need to install a special pressure accumulator in the middle of the pipe, and is easy to pipe and has no difficulty in space.

[Means for solving problems]

In view of this, in the present invention, a cylinder block is provided on a base body that supports a motor, and a plunger that is axially reciprocated by power transmission from the motor is housed in the cylinder of the cylinder block, and the discharge port of the cylinder is also provided. On the premise of a hydraulic pump device in which a discharge passage connected to a pipe via a check valve is connected, a pressure container is provided on the base body, and a partition member capable of displacing the inside of the pressure container according to the pressure separates an air chamber and an oil chamber. And a metal bellows is used for the partition member, or a multilayer film in which a gas barrier polymer thin film and a rubber-like elastic polymer film are stacked, and high-pressure gas is enclosed in the air chamber, and the oil chamber is also used. Is connected to the discharge passage downstream of the check valve, and the oil pressure in the discharge passage between the oil chamber and the discharge passage is lower than the gas pressure in the air chamber. Therefore, self-sealing means for confining the oil in the oil chamber is provided when the partition member bends in the direction in which the volume of the oil chamber decreases.

[Action]

With this configuration, oil is sucked into the cylinder when the plunger reaches the expansion process, and the sucked oil is discharged from the discharge port to the discharge passage through the check valve when the plunger shifts to the compression process. . When the hydraulic pressure in the discharge passage becomes higher than the filling pressure of the air chamber in the pressure container, the discharge passage communicates with the oil chamber in the pressure container, so the oil in the discharge passage flows into this oil chamber, The volume of the oil chamber increases.
Then, the partition member is displaced in the pressure container according to the volume change of the oil chamber, and absorbs the increase in the hydraulic pressure in the discharge passage.
Further, when the hydraulic pressure in the discharge passage decreases, the partition member receives the enclosed pressure of the air chamber and is pushed back, the volume of the oil chamber decreases, and the oil in the oil chamber is discharged into the discharge passage.

In this way, when pulsation occurs in the discharge passage, the volume of the oil chamber connected to this discharge passage automatically fluctuates according to the oil pressure, so the pulsation is absorbed, and the discharge flow rate and discharge of oil in the discharge passage are reduced. The pressure is smoothed.

In the present invention, since the pressure vessel for absorbing the pulsation in the discharge passage is provided on the base body and integrated with the main part of the pump, it can be compactly incorporated into the pump itself.

Therefore, it is not necessary to provide special accessories such as a pressure accumulator and a pipe joint in the middle of the piping, and the piping can be simplified correspondingly, and a space for installing the pressure accumulator is also unnecessary. When the pressure vessel for pulsation absorption is integrated with the main part of the pump as in the present invention, it becomes difficult to maintain the inside of the pressure vessel, but the partition member of the present invention has a metal bellows or gas barrier with an extremely high gas barrier property. Since a multi-layered film in which a polymer thin film and a rubber-like elastic polymer film are bonded together is adopted, even if a high pressure gas of several 10 kg / cm ² or more is enclosed in the air chamber partitioned by the partition member, Does not dissolve in the oil and a decrease in gas pressure over time is avoided, so that maintenance-free interior of the pressure vessel can be realized.

〔Example〕

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

Strut type cylinder piston device 1 shown in FIG.
Includes a cylinder housing 2 and a hollow piston rod 3 that is inserted so as to be reciprocally movable in the axial direction of the cylinder housing 2. Cylinder housing 2 is outer cylinder 4
And an inner cylinder 5 have a double cylinder structure, and an oil chamber 6 filled with oil is formed inside the inner cylinder 5.

One end of the piston rod 3 is introduced into the oil chamber 6,
A piston 7 is attached to this one end. The piston 7 divides the oil chamber 6 into a compression side oil chamber 6a and an extension side oil chamber 6b, and the piston 7 is provided with an orifice port (not shown) and a plate valve for opening and closing the orifice port.

Piston rod 3 derived from cylinder housing 2
A bracket 9 for fixing the mount insulator 8 is attached to the end portion of the. The bracket 9 has an oil port
10 is provided, and this oil supply port 10 is provided with a piston rod 3
To the compression side oil chamber 6a via an oil passage 11 inside. Further, the bracket 9 is provided with a sub tank 12 separate from the cylinder housing 2. The sub-tank 12 is partitioned into an oil chamber and an air chamber by a bellows (not shown). The oil chamber in the sub-tank 12 is passed through the communication passage 13 provided in the bracket 9 to the oil passage 11 of the piston rod 3 and the oil feed port 10. It is connected to.

A pipe 15 extending to the outside of the cylinder piston device 1 is connected to the oil supply port 10. The upstream side of the pipe 15 is the feed pipe 15a
And return pipe 15b, and these feed pipes 15a
The return pipe 15b is connected to the hydraulic pump unit 19 via a check valve 16 and solenoid valves 17 and 18.

As shown in FIGS. 1 and 2, the hydraulic pump unit 19 includes a base plate 20 that constitutes a base body,
A DC motor 21, which uses an automobile battery as a power source, is supported on one end surface of the base plate 20. The rotating shaft 22 of the DC motor 21 is introduced into a through hole 20a formed in the base plate 20, and one end opening of this through hole 20a is the DC motor 2
It is liquid tightly closed at 1. A cam plate 24 is attached to the rotary shaft 22 of the DC motor 21, and a cam surface 25 is formed on the tip end surface of the cam plate 24.

An oil tank 26 is supported on the surface of the base plate 20 opposite to the motor 21, and the oil tank 26 is filled with oil. A pump base 27 is housed in the oil tank 26. The pump base 27 is supported by the base plate 20 and closes the other end opening of the through hole 20a.
An oil inflow chamber 23 that is partitioned from the outside is formed in 0.
The pump base 27 is located on the opposite side of the DC motor 21 with the base plate 20 interposed therebetween.
A cylinder mounting hole 28 is formed along the axial direction of the motor 21. One end of the cylinder mounting hole 28 communicates with the oil inflow chamber 23, and the cylinder mounting hole 28 accommodates a cylinder block 29 and an end member 30 for fixing the cylinder block 29 in place.

The cylinder block 29 is a cylinder 31 that opens into the oil inflow chamber 23.
The plunger 32 is fitted in the cylinder 31 so as to be reciprocally movable in the axial direction. One end of the plunger 32 is led out into the oil inflow chamber 23 and slidably contacts the cam surface 25 of the cam plate 24. The plunger 32 is a coil spring.
It is always urged by 33 toward the cam surface 25.

A suction port 34 is opened on the inner surface of the cylinder 31, and the suction port 34 communicates with the oil tank 26 through a suction passage 35. The suction passage 35 is provided with a low-pressure check valve 36 that allows only the flow of oil toward the suction port 34, and the oil that has flowed into the suction passage 35 pushes away the ball 36a and flows into the suction port 34. There is. On the upstream side of the low pressure check valve 36, a communication passage 37 that connects the suction passage 35 and the oil inflow chamber 23 to each other.
Is provided.

Further, a discharge port 38 having a small diameter is opened at the end of the cylinder 31 on the compression side, and the discharge port 38 communicates with a space 39 between the cylinder mounting hole 28 and the cylinder block 29. Outlet
The high pressure check valve 40 that allows only the flow of oil from the cylinder 31 to the space 39 is provided in the 38, and the oil pressurized in the cylinder 31 pushes the ball 40a away and flows into the space 39. Has become. The space 39 communicates with a discharge passage 41 provided in the pump base 27 and the base plate 20,
The feed pipe 15a is connected to the outlet 42 of the discharge passage 41.

A return passage 43 is formed in the base plate 20 and communicates with the oil tank 26. A return pipe 44 is provided in a return port 44 of the return passage 43.
15b is connected. The return passage 43 and the discharge passage 41 are communicated with each other via a relief passage 45, and a relief valve 46 is provided in a communicating portion between the relief passage 45 and the return passage 43. The relief valve 46 includes a poppet 46a that opens and closes the relief passage 45, and the poppet 46a is constantly urged by a coil spring 47 in a direction to close the relief passage 45.

Reference numeral 48 in the figure is an adjusting screw for adjusting the operating pressure of the relief valve 44.

By the way, a pressure container 50 is welded to the pump base 27 in the oil tank 26 so as to surround the outer periphery of the pump base 27, and the pressure container 50 is liquid-tightly separated from the oil tank 26. , Crushed in oil. Pressure tank 50
The inside is divided into two chambers by a bellows 51 as a partition member, and the inside of the bellows 51 is an oil chamber 52 and the outside is an air chamber 53. The tip of the bellows 51 is closed by a bellows lid 54. The bellows lid 54 faces the end surfaces of the pump base 27 and the end member 30, and the end member 30 is formed with an oil passage 55 that connects the oil chamber 52 and the space 39. Further, an inert gas such as nitrogen gas is filled in the air chamber 53 at a high pressure, and when the filling pressure of the inert gas is higher than the oil pressure in the oil chamber 52, the bellows lid 54 pumps. Base 27 and end member 30
Touches the end face of. A seal material 57 is provided between the end member 30 and the bellows lid 54. The sealing material 57 and the bellows lid 54 form a self-sealing means 58. In the self-sealing means 58, when the oil pressure on the discharge passage 41 side becomes lower than the gas pressure in the air chamber 53, the bellows 51 bends in the direction in which the volume of the oil chamber 52 decreases due to the gas pressure, and the bellows lid 54 causes the end member 30 to move. By being pressed against the sealing material 57 of and being in close contact with each other,
The oil is confined in the oil chamber 52.

As the bellows 51, a metallic material such as stainless steel, or as shown in FIG. 3, a polymer thin film 60 located on the air chamber 53 side is used.
And a rubber-like elastic polymer film 61 located on the oil chamber 52 side are stacked in the thickness direction to form a multilayer film having a high gas barrier property.
The polymer thin film 60 is preferably an ethylene / vinyl alcohol copolymer, polyvinyl chloride, polyvinylidene chloride, a compound containing acrylonitrile, or the like, and as the rubber-like elastic polymer film 61, for example, polyurethane elastomer, polyester elastomer, Elastomers, such as polyamide elastomers, which have a low flexural modulus and do not lose their flexibility in cold weather are preferred.

In such a configuration, when the cam plate 24 is rotationally driven by the DC motor 21, the plunger 32 reciprocates according to the shape of the cam surface 25, and the volume of the cylinder 31 changes. That is, during the compression process in which the plunger 32 is pushed into the cylinder 31, the low pressure check valve 36 is closed and the high pressure check valve 40 is closed.
Is opened, and the oil pressurized in the cylinder 31 is discharged from the discharge port 38. At this time, the plunger 32 is pulled out from the oil inflow chamber 23, so that the inside of the oil inflow chamber 23 has a negative pressure, and the oil in the oil tank 26 is sucked into the oil inflow chamber 23 through the suction passage 35 and the communication passage 37. Get caught

On the other hand, when the plunger 32 reaches the expansion process in which it is pulled out from the cylinder 31, the volume of the cylinder 31 increases and at the same time the suction port 34 is opened, the high pressure check valve 40 is closed and the low pressure check valve 36 is opened, and the discharge port 38 The oil discharge is stopped.
Further, at this time, the plunger 32 is pushed into the oil inflow chamber 23, so that the oil sucked into the oil inflow chamber 23 pushes the ball 36a of the low pressure check valve 36 away from the communication passage 37 and the suction port 34.
Into the cylinder 31 from there. This sucked oil is pressurized when the plunger 32 is pushed back into the cylinder 31, and the ball 40a of the high pressure check valve 40 is pressurized.
Is discharged and discharged from the discharge port 38 into the space 39.

Then, the discharged oil is supplied to the feed pipe 15a through the discharge passage 41. When the solenoid valve 17 of the feed pipe 15a is opened and the pressurized oil chamber 6a of the cylinder 2 is replenished with pressurized oil, the amount of protrusion of the piston rod 3 is increased and the vehicle height can be increased. In addition, the solenoid valve 17 of the feed pipe 15a
Closed, and open the solenoid valve 18 of the return pipe 15d to open the compression side oil chamber 6
The oil of a is discharged into the oil tank 26 through the return passage 43,
As a result, the piston rod 3 is depressed and the vehicle height is lowered.

In such a hydraulic pump device 19, the plunger 32
Since the oil pressure is acting on the bellows lid 54 via the oil passage 55 while the engine is being driven, the oil pressure in the discharge passage 41 is changed to the enclosed gas in the air chamber 53 as the high pressure check valve 40 is opened and closed. When the pressure becomes higher than the pressure, the bellows lid 54 is pushed out in the direction away from the pump base 27, and the bellows 51 extends as shown by an imaginary line in FIG. By extending the bellows 51, the oil chamber
The volume of 52 increases, a part of the oil discharged from the discharge port 38 flows into the oil chamber 52, and the increase in hydraulic pressure is absorbed.

When the hydraulic pressure in the discharge passage 41 becomes lower than the filling pressure in the air chamber 53, the bellows lid 54 contracts to reduce the volume of the oil chamber 52, and the oil in the oil chamber 52 passes through the oil passage 55 to reach the discharge passage. Exhaled into 41. Further, due to the decrease in the volume of the oil chamber 52, the bellows lid 54 comes into contact with the end surfaces of the pump base 27 and the end member 30, and the communication between the oil chamber 52 and the oil passage 55 is cut off. For this reason, the oil is confined in the oil chamber 52 and the hydraulic pressure is applied to the inside of the bellows 51, so that the bellows 51 is not crushed even if it receives the sealing pressure in the air chamber 53.

Further, the relief passage 45 is provided in the poppet 46a of the relief valve 46.
The hydraulic pressure in the discharge passage 41 is constantly acting through, and when this hydraulic pressure approaches the maximum pressure of the air chamber 53, the poppet 46a opens the relief passage 45 against the biasing force of the coil spring 47,
The oil in the discharge passage 41 is returned to the oil tank 26 via the return passage 43. Therefore, the oil pressure of the oil chamber 52 does not exceed the maximum pressure of the air chamber 53, and the breakage of the bellows 51 can be prevented.

As described above, when pulsation occurs in the discharge passage 41, the bellows 51 expands and contracts and the volume of the oil chamber 52 that is continuous with the discharge passage 41 changes, so that the pulsation can be absorbed, and the discharge passage can be absorbed.
The discharge flow rate and discharge pressure of oil in 41 are smoothed. Therefore, the vibration of the pipe 15 that connects the discharge passage 41 and the oil supply port 10 can be prevented, and noise can be reduced.

In this embodiment, the pressure vessel 50 containing the bellows 51 is
Since it is attached to the pump base 27, a mechanism for absorbing this pulsation can be integrated with main parts of the pump such as the cylinder block 29 and the plunger 32, and can be compactly packaged.

Therefore, it is not necessary to provide an accessory such as a special pressure accumulator or a pipe joint in the middle of the pipe 15, and accordingly, the pipe 15 can be simplified and a space for installing the pressure accumulator is not required, This is convenient when arranging in a narrow space.

Moreover, by disposing the pressure container 50 in the oil tank 26, in the unlikely event that the pressure container 50 is damaged, the internal pressure of the oil tank 26 rises, and this pressure increases the rotating shaft 22 of the DC motor 21.
It will be added to the seal member of and damage this seal part,
The oil and the inert gas pass through the inside of the DC motor 21 and are jetted out from the drain port.

Therefore, when the pressure vessel 50 is broken, oil can be prevented from splashing around the drain port of the DC motor 21, and the oil splash can be easily prevented compared to the case where a pressure accumulator is provided in the middle of the pipe 15. Can be done.

The present invention is not limited to the first embodiment described above, and FIGS. 5 to 7 show a second embodiment of the present invention.

In this embodiment, a cylinder block 29, a plunger 32, a high pressure check valve 40 and a low pressure check valve 36 are arranged inside the base plate 20, and the cylinder block 29 and the plunger 32 are orthogonal to the rotary shaft 22 of the DC motor 21. It is provided along the direction. Rotation axis of DC motor 21
One end of 22 and the end of the plunger 32 are recesses that form the oil inflow chamber 23.
A bearing 72 is eccentrically attached to the tip of the rotary shaft 22. The bearing 72 rotates integrally with the rotary shaft 22 and its outer peripheral surface slidably contacts one end of the plunger 32.
The eccentric rotation causes the plunger 32 to reciprocate in the axial direction. An oil passage 73 that connects the oil inflow chamber 23 and the oil tank 26 is formed in the base plate 20, and the oil passage 73 is also connected to the suction passage 35 that is connected to the low pressure check valve 36. A return passage 43 communicates with the oil inflow chamber 23, and the oil from the cylinder piston device 1 is returned to the oil tank 26 via the oil inflow chamber 23 and the oil passage 73.

The discharge passage 41 and the space 39 in the pump base 27 are communicated with each other via an oil delivery passage 74 provided in the base plate 20,
Further, the discharge passage 41 is connected to the delivery port 42 through a communication passage 75 provided in the pump base 27 and the base plate 20.

According to the configuration of this embodiment, the oil in the oil tank 26 is sucked into the oil inflow chamber 23 via the oil passage 73 when the plunger 32 is in the compression process. This sucked oil is supplied to the oil passage 73, the suction passage 35, and the low pressure check valve when the plunger 32 reaches the expansion process.
The gas is sucked into the cylinder 31 through the suction port 36 and the suction port 34, pressurized in the cylinder 31, and then discharged from the delivery port 42 through the discharge port 38, the space 39, the discharge passage 41, and the communication passage 75.

By the way, in this embodiment, the plunger 32 is provided in the direction orthogonal to the rotary shaft 22 of the DC motor 21, and the bearing 72 which is eccentrically rotated integrally with the rotary shaft 22 is slidably brought into contact with one end of the plunger 32. Since the reciprocating motion is performed, the frictional force generated at the sliding contact portion between the plunger 32 and the bearing 72 can be suppressed to be small. Therefore, almost no force is applied to the plunger 32 in the radial direction,
Accordingly, the reciprocating motion of the plunger 32 is smoothly performed, and the durability of the plunger 32 is improved.

Further, FIGS. 8 and 9 show a third embodiment of the present invention in which the oil tank 81 is a separate body.

In this case, the pump base 27 is DC with respect to the base plate 20.
It is arranged on the same side as the motor 21 and is aligned with the DC motor 21. As the oil tank 81 is separated, the suction passage 35 of the base plate 20 is provided with an oil suction port 82 connected to the oil tank 81, and the base plate 20 is provided with an oil inflow chamber 23. A relief passage 83 that communicates with the space 39 is formed, and a relief valve 46 is installed in the relief passage 83.

According to this configuration, the flow path until the oil sucked from the oil suction port 82 is discharged from the delivery port 42 is the second path described above.
Similar to the embodiment, but when the oil pressure in the space 39 approaches the maximum pressure of the air chamber 53 and the relief valve 46 opens, the oil in the space 39 is temporarily returned to the oil inflow chamber 23 through the relief passage 83, Is returned to the oil tank 81 through the oil passage 73, the suction passage 35, and the oil suction port 82.

In this embodiment, the oil tank 81 is a separate body and the pressure vessel 50 and
Since the DC motor 21 and the DC motor 21 are arranged side by side on the same side of the base plate 20, there is an advantage that the occupied space of the hydraulic unit 19 is smaller than that in the first and second embodiments.

The partition member for partitioning the inside of the pressure container is not limited to the bellows, and a diaphragm or a rubber bag may be used, for example.

[Effect of device]

According to the present invention described in detail above, since a high-pressure compressed gas for pulsation absorption is enclosed in the air chamber that is partitioned from the oil chamber by the partition member, it is extremely useful, for example, in a hydraulic / pneumatic suspension system for a vehicle. Since the pulsation generated in the discharge passage can be absorbed even in a hydraulic system in which a high hydraulic pressure is generated, the discharge flow rate and discharge pressure of oil can be smoothed, and noise due to vibration of the pipe can be prevented in advance. Even if high-pressure compressed gas is enclosed in the air chamber, the partition member is backed up by the oil trapped in the oil chamber by the self-sealing means when the oil pressure drops, so the partition member is crushed by the high-pressure gas. Can be avoided.

In addition, since the pressure vessel that absorbs pulsation is integrated with the main part of the pump, it can be compactly incorporated into the pump itself, and special accessories such as pressure accumulators and pipe joints are provided in the middle of the pipe that connects to the discharge passage. There is no need to provide.
Therefore, the piping can be simplified correspondingly, and there is no need to secure a space for installing the pressure accumulator, which is advantageous when installing in a narrow space. Moreover, it is possible to provide a hydraulic pump device having a pulsation prevention function that is compact and can realize maintenance-free inside the pressure vessel, is easy to maintain, and is easy to use.

[Brief description of drawings]

FIGS. 1 to 4 show a first embodiment of the present invention.
The drawing is a cross-sectional view of the hydraulic pump device, FIG. 2 is a front view of the pressure vessel side with the oil tank removed, FIG. 3 is a cross-sectional view of the bellows, FIG. 4 is a cross-sectional view of the cylinder piston device, and FIG. 7 to 20 show a second embodiment of the present invention, FIG. 5 is a sectional view of a hydraulic pump device, FIG. 6 is a sectional view taken along line VI-VI in FIG. 5, FIG. 7 is an oil tank, The pump base and the pressure vessel are removed and the front view is seen from the direction of the line VII in FIG. 5, FIGS. 8 and 9 show the third embodiment of the present invention, and FIG. 8 is a sectional view of the hydraulic pump device. FIG. 9 is a sectional view taken along the line IX-IX in FIG. 15 ... Piping, 20 ... Base (pump base), 21 ... Motor (DC motor), 29 ... Cylinder block, 31 ... Cylinder, 32 ... Plunger, 38 ... Discharge port, 40 ... Check valve (High pressure check valve), 41 ... Discharge passage, 50 ... Pressure vessel, 51 ... Partitioning member (bellows), 52 ... Oil chamber, 53
...... Air chamber.

Claims (1)

[Scope of utility model registration request] 1. A cylinder block (29) is provided on a base body (20) for supporting a motor (21), and the cylinder block (2) is provided.
The cylinder (31) of (9) accommodates a plunger (32) which is axially reciprocated by power transmission from the motor (21), and a check valve (38) is installed in the discharge port (38) of the cylinder (31). In a hydraulic pump device in which a discharge passage (41) connected to a pipe (15) through a pipe (40) is connected, a pressure vessel (50) is provided in the base body (20), and the pressure vessel (50) is responsive to pressure. It is divided into an air chamber (53) and an oil chamber (52) by a displaceable partition member (51), and a metal bellows is used for the partition member (51), or a gas barrier polymer thin film (60) and a rubber-like elastic material are used. A multi-layered film in which a molecular film (61) is stacked is used, high-pressure gas is enclosed in the air chamber (53), and the oil chamber (52) is provided with a discharge passage (downstream of the check valve (40). 41) and above the oil chamber (5
2) and the discharge passageway (41), the oil pressure in the discharge passageway (41) becomes lower than the gas pressure in the air chamber (53), and
Self-sealing means (5) for confining the oil in the oil chamber (52) when the partition member (51) bends in the direction in which the volume of 2) decreases.
8) A hydraulic pump device characterized by being provided.