JPH02225802A - Accumulator - Google Patents

Abstract

PURPOSE:To dispense with the installation space and effectively eliminate the pulse by providing an inflow port connected to a hydraulic pump on a first end side member, and an outflow port on a second end side member of a housing which house a bellows to seal gas with a pressure more than atmospheric pressure. CONSTITUTION:A first end side member 16 provided with an inflow port 21 and a second end side member 17 on which one end of a belows body 31 is installed and an outflow port 22 is formed are arranged on both end of a housing 15. The other end of the bellows 31 is blocked by a bellows cap 32 having a valve body 35 to form a metal bellows 30 as an air chamber, and an oil chamber 45 is formed by an outer side of the metal bellows 30 and an inner face of the housing 15. The discharge oil of a pump 11 is wholly introduced into the oil chamber 45, and pulse is effectively eliminated. The space for installation is thus dispensed with, thereby the arrangement of the pipe line is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an accumulator for absorbing pulsation used in various hydraulic devices.

[Prior Art] As shown in FIG. 7, a conventional hydraulic system includes a hydraulic pump 1 and a hydraulic machine r operated by the pump 1.
A2, piping 3 connecting these pumps 1 and hydraulic equipment 2
, 4, and an accumulator 5 for smoothing the pulsating component of the oil discharged from the pump 1. The accumulator 5 has an oil chamber 7 and an air chamber 8 inside a housing 6, seals high-pressure gas in the air chamber 8, and fills the oil chamber 7 with oil to reduce the pulsating component of the oil discharged from the pump 1. The oil is absorbed by the compression and expansion of the gas in the air chamber 8. In order to efficiently exhibit the damping performance of the accumulator 5 regardless of the pulsation frequency, the entire amount of oil discharged from the pump 1 is absorbed by the oil in the accumulator 5. It is said that a piping structure in which the fluid flows into the chamber 7 and then leads to the hydraulic equipment 2 is preferable. Therefore, in this case, the accumulator 5 has an inlet 9a and an outlet 9.
By arranging the pumps b in parallel, the entire amount of oil discharged from the pump passes through the oil chamber 7.

[Problems to be Solved by the Invention] The conventional accumulator 5 described above has an inlet 9a and an outlet 9 at one end of the housing 6 (housing cap, etc.).
b are arranged in parallel, the housing 6 of the accumulator 5 protrudes in a direction perpendicular to the pipes 3 and 4. Therefore, this accumulator 5 is not part of pipe 3.4 (pipe 3.4).
, 4 shall be treated as separate equipment. Therefore, a space for installing the accumulator 5 must be secured separately from the pipes 3 and 4, and there are problems such as the shape of the joint becomes ms.

Therefore, an object of the present invention is to provide an accumulator that can be treated as a part of piping and that makes it easy to secure installation space.

[Means for Solving the Problems] The accumulator of the present invention developed to achieve the above object includes a hollow housing that covers a first end and a second end located at both ends in the axial direction, and a hollow housing that covers a first end and a second end located at both ends in the axial direction. A bellows that is housed inside and has a metal bellows body that is expandable and retractable in the axial direction of the housing, and a space inside the housing partitioned by the bellows that is located on the inner surface of the bellows and has a pressure higher than atmospheric pressure. an air chamber in which gas is sealed; an oil chamber defined on the side surrounded by the outer surface of the bellows and the inner surface of the housing of the space inside the housing partitioned by the bellows; The housing includes an inlet provided on a member on the first end side, and an outlet provided on the member on the second end side of the housing, which communicates with the pressure device mentioned above.

[Operation] Oil containing 1 minute of pulsating acid discharged from the pump flows into the oil chamber through the inlet in the accumulator, and exits the outlet and is sent to the hydraulic equipment. An inlet and an outlet are provided at both ends of the housing, and piping is connected to the coaxial line I- to these inlets and outlets, so that all of the oil discharged from the pump is transferred to the two-leg oil chamber. At the same time, it flows in the direction of the axis of the housing and is sent to the hydraulic equipment side. The pulsations of oil in the oil chamber act on the gas in the air chamber, and the pulsations are absorbed by the compression and expansion of the gas. An axial flow type accumulator having such a configuration can be handled as a part of piping.

[Example] The first example of the present invention will be described above with reference to FIG. 1. The accumulator 10 shown in FIG. 1 is provided between a hydraulic pump 11 and a hydraulic device 12 operated by the pump 11. This accumulator 10 includes a hollow cylindrical housing 15. Then, on the left side of the housing 15 in the drawing, there is a member 16 on the first end side.
However, a second end member 17 is also provided on the right side in the figure.

An inlet 2 is provided in the center of the member 16 on the first end side of the housing 15.
1 is opened, and an outlet 22 is provided in the center of the member 17 on the second end side.

The inlet 21 and the outlet 22 are located on the central axis of the housing 15. A male thread 23 provided at the inflow port 21 is connected to one end of an inflow pipe 24 via a pipe joint (not shown). The other end of the pipe 24 is connected to the discharge port of the pump 11. Female thread 25 provided at the outlet 22
is connected to one end of the outflow side piping 26 via a pipe joint (not shown). The other end of the pipe 26 is connected to an inlet of the hydraulic equipment 12.

A metal bellows 30 is housed inside the housing 15. The bellows 30 includes a bellows body 31 that is expandable and retractable in the axial direction of the housing 15, and a bellows cap 32 that closes one end of the bellows body 31. The bellows body 31 has a thickness of 0. l or 0
．． A stainless steel plate of approximately 3 mm is formed into a predetermined bellows shape by plastic processing such as hydraulic forming or roll forming. However, metals other than stainless steel may be used. The other end 33 of the bellows body 31 is the housing 15
is airtightly fixed to a member 17 on the second end side. Valve body 3
5 and the valve seat 36 constitute a self-sealing means 37, which will be described later, but this self-sealing means 37 may be omitted.

A bellows guide member 3 is attached to the outer periphery of the bellows body 31.
8 is attached. This guide member 38 is used to ensure a predetermined clearance between the bellows body 31 and the inner surface of the housing 15 and to reduce sliding resistance between the bellows body 31 and the housing 15.

This guide member 38 is provided with a notch large enough to allow oil to flow smoothly between the bellows body 31 and the housing 15.

In the internal space of the housing 15 partitioned by the bellows 30, an air chamber 41 is defined on the inner surface side of the bellows 30. This air chamber 41 is filled with an inert gas such as nitrogen.

The gas filling pressure is determined depending on the discharge pressure of the pump 11 and the pulsation absorption characteristics, and is, for example, several kg/c-
It is encapsulated under a pressure higher than that. This gas is sealed into the air chamber 41 through a gas supply hole 43 that can be closed by a stopper 42 . The pressure of the gas sealed in the air chamber 41 is
It acts in the direction of extending 0.

Further, an oil chamber 45 is provided on the side surrounded by the outer surface of the bellows 30 and the inner surface of the housing 15. The oil chamber 45 communicates with the pump 11 via the inlet 21 and also communicates with the hydraulic equipment 12 via the flow section 46 provided in the member 17 and the outlet 22. In this embodiment, the hole diameter of the flow section 46 is smaller than the inner diameter of the inlet port 21, and the hole diameter of the flow section 46 is also smaller than the inner diameter of the outlet pipe 26. The flow portions 46 may be provided at a plurality of locations avoiding the outlet 22.

Next, the operation of the accumulator 10 having the above configuration will be explained.

The entire amount of the water containing the pulsating component discharged from the hydraulic pump 11 flows into the oil chamber 45 via the inflow side pipe 24 and the inflow port 21 . The oil that has flowed into the oil chamber 45 flows in the housing 15 in the axial direction, passes through the flow section 46, and reaches the outlet 2.
2 to the hydraulic equipment 12. The pulsation of oil pressure generated by the rotation of the pump 11 acts on the oil chamber 45 and also acts on the air chamber 41 via the oil in the oil chamber 45 . Therefore, the pulsating component is absorbed by the compression and expansion of the gas within the air chamber 41. When the air chamber 41 is compressed, the bellows 30 bends in the direction of contraction, and when the air chamber 41 expands, the bellows 3
Deflects in the direction in which 0 extends.

Since the flow section 46 on the upstream side of the outlet 22 serves as a constriction section, the oil that has flowed into the oil chamber 45 is in a state in which outflow from the oil chamber 45 is suppressed. Therefore, a change in the volume of the oil discharged from the pump 11 is replaced by a change in the volume of the gas in the air chamber 41 in an a-effect manner.

The molded bellows 30 of this embodiment can be constructed to be lighter than a welded bellows in which bellows elements are sequentially welded in the axial direction. Excellent response to expansion. Since the bellows 30 is made of metal,
Even if the bellows 30 is thin, it exhibits extremely good gas barrier properties, so the gas in the air chamber 41 will not dissolve into the oil in the oil chamber 45.

In the second embodiment shown in FIG. 2, a bellows fixing base 50 is built into the housing 15 near the member 17 on the second end side.

The gas supply hole 43 provided in this base 50 is connected to the air chamber 4.
1 is filled with gas at a predetermined pressure, and then a steel ball 55 is driven in and caulked to seal it airtight.

Further, the base 50 is provided with a flow section 46.

The other basic structure and operation are the same as those of the first embodiment.

In the third embodiment shown in FIGS. 3 and 4, a valve body 35 is provided on the outer surface of the bellows cap 32 to prevent the bellows cap 32 from applying direct force to the member 17 on the second end side. It is provided. The valve body 35 is made of a rubber-like elastic material such as urethane elastomer or silicone resin, and faces an annular valve seat 36 around the outlet 22 . These valve body 35 and valve seat 36 are connected to the housing 1 when the bellows 30 extends beyond a predetermined stroke.
A self-sealing means 37 for trapping oil between the inner surface of the bellows body 31 and the bellows body 31 is provided.

Further, a valve chamber 70 is provided on the inlet 21 side, and a check valve 71 is accommodated in the valve chamber 70. The check valve 71 includes, for example, a spherical valve body 72 and a compression spring 73 that biases the valve body 72 in the valve-closing direction. Valve chamber 70
communicates with the oil chamber 45 via the flow section 74. Pressure oil introduced from the inlet 21 pushes open the check valve 71, passes through the flow section 74, flows into the oil chamber 45, and then flows into the outlet 2.
2 and sent to the hydraulic equipment 12.

If the pressure in the oil chamber 45 or the inlet 21 and outlet 22 drops below the gas filling pressure for some reason, the check valve 71 closes, thereby closing the inlet 21, as shown in FIG. At the same time, the bellows 30 expands due to the pressure of the gas in the air chamber 41. When the bellows 30 is bent to a predetermined stroke, the valve body 3 of the self-sealing means 37
5 is closed, and the outlet 22 is closed. As a result, the bellows body 31 no longer flexes in the axial direction, and oil is trapped in the gap 47 between the inner surface of the housing 15 and the outer surface of the bellows 30. Since oil is substantially incompressible, the outer surface of bellows 30 is backed up by oil trapped in gap 47. Therefore, excessive bending of the bellows body 31 can be prevented. Therefore, the pressure resistance required of the bellows body 31 is relaxed, and the thickness of the bellows body 31 can be reduced. It goes without saying that the check valve 71 can be implemented in various forms other than the above embodiments.

The fourth embodiment shown in FIGS. 5 and 6 has a housing 1
A bellows fixing base 80 is built into the axial center of 5.
Moreover, there is a pair of bellows 30.30 on both sides of the base 80.
are arranged symmetrically. Each bellows 30, 30 has the same structure, and the two air chambers 41, 41 communicate with each other via a gas passage 81 provided in the base 8o.

Further, both oil chambers 45 and 45 communicate with each other via an oil passage 82. Therefore, the pressure oil introduced from the inlet 21 first enters the high-pressure side oil chamber 45a on the left side in the figure, passes through the oil passage 82, enters the low-pressure side oil chamber 45b on the right side in the figure, and then passes through the outlet 22. It is sent to the hydraulic equipment 12. In this fourth embodiment, the two air chambers 41, 41 work together to effectively absorb pulsations. Inlet 2
1 and the outlet 22 drop below the gas filling pressure, the self-sealing means 37.3 is activated as shown in FIG.
When the valve bodies 35 and 35 of No. 7 close, the inlet port 21
The outflow port 22 is liquid-tightly closed. Therefore, as in the previous embodiments, the bellows body 31 is backed up by the oil trapped in the gaps 47, 47.

Note that the accumulator 10 of the present invention may be directly connected to the discharge port of the hydraulic pump 11, or may be provided at the inlet of the hydraulic equipment 12.

[Effects of the Invention] According to the present invention, the entire amount of oil discharged from the pump can be introduced into the oil chamber in the accumulator, and pulsation can be effectively absorbed by the gas in the accumulator. Since the oil in the accumulator is an axial flow type in which the oil flows in the axial direction of the housing, and each piping can be connected to both ends of the housing almost on the same axis, this accumulator can be treated as a part of the piping. , no special space is required for installing the accumulator, and the shape of the piping joints is also simple.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an accumulator showing a first embodiment of the present invention, FIG. 2 is a cross-sectional view of an accumulator showing a second embodiment of the present invention, and FIG.
FIG. 4 is a sectional view showing the operation of the accumulator shown in FIG. 3. FIG. 5 is a sectional view showing the fourth embodiment of the invention. , Figure 6 is the fifth
A sectional view showing the operating mode of the accumulator shown in the figure,
FIG. 7 is a sectional view showing a conventional accumulator. 10...Accumulator, 11...Hydraulic pump, 1
2...Hydraulic equipment, 15.../1Using, 16...
- Member on the first end side, 17... Member on the second end side, 21.
... Inflow port, 22 ... Outflow port, 30 ... Metal bellows, 31 ... Bellows body, 37 ... Self-sealing means, 41 ... Air chamber, 45, 45a, 45b - ... Oil Room.

Claims (2)

[Claims] (1) An accumulator provided in the middle of an oil passage connecting a hydraulic pump and a hydraulic device operated by oil discharged from the pump, the accumulator having first and second ends located at both ends in the axial direction. a hollow housing having a hollow housing; a bellows housed inside the housing and having a metal bellows body that is expandable and retractable in the axial direction of the housing; and a space inside the housing partitioned by the bellows on the inner surface side of the bellows. and an oil chamber defined on the side surrounded by the outer surface of the bellows and the inner surface of the housing among the space inside the housing partitioned by the bellows. , an inlet that communicates with the pump and is provided on a member on the first end side of the housing, and an outlet that communicates with the hydraulic equipment and is provided on a member on the second end side of the housing. An accumulator characterized by: (2) Self-sealing means is provided inside the housing to trap oil between the outer surface of the bellows and the inner surface of the housing by blocking the inlet or outlet when the bellows is extended beyond a predetermined stroke. 2. The accumulator according to claim 1.