JPH08312525A - Hydraulic pulsation absorber - Google Patents

Abstract

PURPOSE: To provide a hydraulic pulsation absorber simple in structure and capable of reducing cost. CONSTITUTION: A storage 6 communicated to a hydraulic pressure flow passage 5 is provided in a discharge port block 3 of a hydraulic pump 1, a base plate with a diaphragm 7 installed on it is adhered to an opening end to the outside of this storage 6, working oil 10 flowing in the hydraulic pressure flow passing 5 is introduced to the storage in which the diaphragm 7 is built, and high pressure gas 9 is filled between the diaphragm 7 and the case plate 8. Consequently, a casing of the hydraulic pump can also serve as a housing of an accumulator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pulsation absorbing device for absorbing pulsation of hydraulic oil discharged from a hydraulic pump.

[0002]

2. Description of the Related Art Generally, a hydraulic excavator or the like is equipped with a hydraulic pump such as a gear pump or a piston pump as a hydraulic power source of hydraulic oil. When the hydraulic oil is discharged from the hydraulic pump, the pressure fluctuation of the hydraulic oil is Since so-called pulsation occurs, there is a concern that this hydraulic oil may adversely affect various hydraulic equipment that flows.

Therefore, conventionally, as described in Japanese Utility Model Laid-Open No. 6-18673, an accumulator is attached to the outside of a discharge port block on the discharge side of a hydraulic pump, and the pulsation of hydraulic oil is absorbed by this accumulator. A hydraulic pulsation absorber has been proposed. This accumulator is equipped with a housing that forms the outer shell of the accumulator itself, and a diaphragm that divides the interior of this housing into a gas chamber and a hydraulic chamber. The gas chamber is filled with high-pressure gas, and the hydraulic chamber contains hydraulic pressure. A part of the hydraulic oil discharged from the pump is introduced.

In this conventional hydraulic pulsation absorber,
When the pressure of the hydraulic oil discharged from the hydraulic pump rises and the pressure rises, the diaphragm in the accumulator is pressed toward the gas chamber side, and the gas in the gas chamber is compressed, and the pressure of the hydraulic oil increases. When is lower, the diaphragm is pressed toward the hydraulic chamber, and the gas in the gas chamber expands. By thus compressing and expanding the gas in the gas chamber, the pulsation of the hydraulic oil discharged from the hydraulic pump can be absorbed.

[0005]

However, the above-mentioned prior art requires a housing that forms the outer shell of the accumulator itself, and the pressure of the hydraulic oil acts directly on this housing, so the pressure resistance of the housing is high. Considering the sealing property and the sealing property, the whole structure of the accumulator becomes complicated and the cost is increased.

The present invention has been made in view of the actual situation in the prior art as described above, and an object thereof is to provide a hydraulic pulsation absorbing device which has a simple structure and can reduce the cost.

[0007]

In order to achieve the above object, the present invention provides a hydraulic pulsation absorbing device for absorbing pulsation of hydraulic oil discharged from a hydraulic pump, wherein a part of a casing of the hydraulic pump, for example, A storage chamber is provided in the side portion of the discharge port block for communicating the hydraulic fluid flow path with the outside.
A base plate is attached to the open end of the storage chamber, a diaphragm attached to the base plate is built in the storage chamber, and high-pressure gas is sealed between the base plate and the diaphragm. .

[0008]

[Operation] When pulsation is generated in the hydraulic oil discharged from the hydraulic pump, the hydraulic oil is guided to the storage chamber and acts on the diaphragm, and the gas enclosed between the diaphragm and the base plate responds to the pressure of the hydraulic oil. The pulsation of the hydraulic oil is absorbed by the compression or expansion. Here, the diaphragm is built in the storage chamber provided in the casing of the hydraulic pump, and since the casing of the hydraulic pump can also be used as the housing of the accumulator, it is not necessary to specially provide a housing for storing the diaphragm, Therefore, the structure is simple and the cost is low.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a partial sectional view of a hydraulic pump including a hydraulic pulsation absorbing device according to a first embodiment of the present invention, and FIG. 2 is a perspective view of a diaphragm and a base plate included in the hydraulic pulsation absorbing device of FIG. The gear pump type hydraulic pump 1 shown in FIG.
It is connected to a hydraulic oil tank (not shown) via the suction port block 2, connected to a hydraulic hose (not shown) via the discharge port block 3, and further connected to various actuators via a control valve or the like. The hydraulic pulsation absorbing device 4 is additionally provided in the side portion 3a of the discharge port block 3, and has a storage chamber 6 having one end communicating with the outside and the other end communicating with the hydraulic flow passage 5 in the discharge port block 3, It mainly comprises a dome-shaped diaphragm 7 housed in the storage chamber 6 and a base plate 8 mounted on the surface of the side portion 3a of the discharge port block 3 and covering the open end of the storage chamber 6. .

As shown in FIG. 2, the diaphragm 7 is called a prada type made of a polymer material such as rubber, and its peripheral portion is integrally formed on the back surface of the base plate 8 by a fixing means such as adhesion. Installed. A high-pressure gas 9 such as nitrogen gas is sealed between one side (gas chamber) of the diaphragm 7 and the base plate 8, and the other side of the diaphragm 7 receives a part of the hydraulic oil 5 from the hydraulic passage 5. Is introduced. The storage chamber 6 is formed in a cylindrical shape, the inner diameter of which is set to be slightly larger than the outer diameter of the peripheral portion of the diaphragm 7, and the size of the storage chamber 6 in the longitudinal direction (depth direction) is
The length of the diaphragm 7 is set to be the same as that when the diaphragm 7 is most expanded.

A pair of insertion holes 12 are formed in the peripheral portion of the base plate 8, and the mounting plate 11 is inserted into these insertion holes 12 to be fastened, so that the base plate 8 is fixed to the discharge port block 3. It is fixed to the surface of the side portion 3a.
Further, a through hole 13 is formed in the center of the base plate 8, and the high pressure gas 9 filling the inside (gas chamber) of the diaphragm 7 from the through hole 13 is blocked by the plug 14. . On the other hand, on the surface of the side portion 3a of the discharge port block 3, a groove 15 is formed so as to surround the opening end of the storage chamber 6.
Is formed into an annular shape, and the O-ring 16 inserted into the groove 15 ensures the sealing performance between the discharge port block 3 and the base plate 8.

The assembly process of the hydraulic pulsation absorbing device 4 will be briefly described. First, the O-ring 16 is inserted into the groove 15, and then the base plate 8 is attached to the side portion 3a of the discharge port block 3.
Then, the diaphragm 7 attached to the base plate 8 is inserted into the storage chamber 6. When the mounting bolt 11 is inserted into the insertion hole 12 and fastened to the side portion 3a in this state, the storage chamber 6
Since the opening end of is covered with the base plate 8 and the gap between the back surface of the base plate 8 and the side portion 3a of the discharge port block 3 is sealed by the O-ring 16 in the groove 15, Leakage of the hydraulic oil 10 is prevented. Finally, the high-pressure gas 9 is filled into the gas chamber in the diaphragm 7 from the through hole 13 of the base plate 8 at a predetermined pressure, and the plug 14 is fitted into the through hole 13 so that the hydraulic pulsation absorbing device 4 is pumped. It can be incorporated in one discharge port block 3.

In use, the hydraulic pump 1 to the hydraulic oil 10
When the oil is discharged, the hydraulic oil 10 is guided to a hydraulic hose (not shown) via the hydraulic flow path 5 of the discharge port block 3 and also to the inside of the storage chamber 6 of the discharge port block 3. At this time, when pulsation is generated in the hydraulic oil 10 and the pressure increases, the diaphragm 7 contained in the storage chamber 6 is pressed toward the gas chamber side accordingly, so that the high pressure gas 9 in the gas chamber is compressed. When the pressure of the hydraulic oil 10 becomes low, the diaphragm 7 is pressed toward the hydraulic flow path 5 side.
The high pressure gas 9 inside the diaphragm 7 expands. As the high pressure gas 9 in the diaphragm 7 is compressed and expanded in this way, the pulsation of the hydraulic oil 10 discharged from the hydraulic pump 1 is absorbed.

In the first embodiment thus constructed, the discharge port block 3 forming a part of the casing of the hydraulic pump 1 is provided with the storage chamber 6, and the storage chamber 6 has the diaphragm 7 built therein. The casing can also be used as the housing of the accumulator, and as a result, the housing for housing the diaphragm can be omitted, and the overall structure of the hydraulic pulsation absorbing device 4 can be simplified to realize cost reduction. Further, since the base plate 8 integrated with the diaphragm 7 is fixed to the side portion 3a of the discharge port block 3, the diaphragm 7 can be arranged in the storage chamber 6,
Assembling work of the hydraulic pulsation absorbing device 4 can be easily performed. Further, since the storage chamber 6 is provided in the discharge port block 3 which has a relatively large space, it is possible to prevent the hydraulic pump 1 from increasing in size.

FIG. 3 is a partial cross-sectional view of a hydraulic pump provided with a hydraulic pulsation absorbing device according to a second embodiment of the present invention. The same parts as those shown in FIGS. Is attached. That is, 1 is a hydraulic pump, 2 is a suction port block, 3 is a discharge port block, 3a is a side part, 4
Is a hydraulic pulsation absorber, 5 is a hydraulic flow path, 6 is a storage chamber, 8 is a base plate, 9 is gas, 10 is hydraulic oil, 11 is a mounting bolt, 12 is an insertion hole, 13 is a through hole, 14 is a plug, 15
Is a groove and 16 is an O-ring.

The difference between the second embodiment and the first embodiment is that a diaphragm 17 called a bellows type is used instead of the prada type diaphragm.
Other configurations are basically the same. The diaphragm 17 is made of a metal material such as phosphor bronze, and one end thereof is attached to the back surface side of the base plate 8 by means such as welding.

Even in the second embodiment, the hydraulic pump 1
When the hydraulic fluid 10 is discharged from the hydraulic fluid 10, the hydraulic fluid 10 is guided to a hydraulic hose (not shown) via the hydraulic flow path 5 of the discharge port block 3 and also to the inside of the storage chamber 6 of the discharge port block 3. At this time, when the hydraulic oil 10 pulsates and the pressure increases, the diaphragm 17 built in the storage chamber 6 is pressed toward the gas chamber side accordingly, so that the high-pressure gas 9 in the gas chamber is compressed. , The hydraulic oil 1
When the pressure of 0 becomes low, the diaphragm 17 moves to the hydraulic flow path 5
Since it is pressed to the side, the high pressure gas 9 in the diaphragm 7 expands. As the high pressure gas 9 in the diaphragm 7 is compressed and expanded in this way, the pulsation of the hydraulic oil 10 discharged from the hydraulic pump 1 is absorbed. Therefore, the same effect as that of the first embodiment described above can be obtained.

[0018]

As described above, according to the present invention,
Since the diaphragm is built into the storage chamber provided in the casing of the hydraulic pump, the casing of the hydraulic pump can also be used as the housing of the accumulator.As a result, the housing for storing the diaphragm is omitted, and the hydraulic pulsation with a simple structure and low cost An absorber can be provided.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a hydraulic pump including a hydraulic pulsation absorbing device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a diaphragm and a base plate included in the hydraulic pulsation absorbing device of FIG.

FIG. 3 is a partial sectional view of a hydraulic pump including a hydraulic pulsation absorbing device according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Hydraulic Pump 3 Discharge Port Block (Casing) 3a Side 4 Hydraulic Pulsation Absorber 5 Hydraulic Flow Path 6 Storage Chamber 7, 17 Diaphragm 8 Base Plate 9 High Pressure Gas 10 Hydraulic Oil 13 Through Hole 14 Plug

Claims (3)

[Claims] 1. A hydraulic pulsation absorbing device for absorbing pulsation of hydraulic oil discharged from a hydraulic pump, wherein a casing of the hydraulic pump is provided with a storage chamber that communicates the flow passage of the hydraulic oil with the outside. A hydraulic pulsation absorbing device characterized in that a base plate is attached to the opening end, a diaphragm attached to the base plate is built in the storage chamber, and high pressure gas is sealed between the base plate and the diaphragm. . 2. The hydraulic pulsation absorbing device according to claim 1, wherein the storage chamber is provided in a discharge port block connected to a discharge side of the hydraulic pump. 3. The hydraulic pulsation absorbing device according to claim 1, wherein the base plate is provided with a through hole for enclosing the high-pressure gas.