WO2002084127A1

WO2002084127A1 - Accumulator

Info

Publication number: WO2002084127A1
Application number: PCT/JP2001/003199
Authority: WO
Inventors: Kimihisa Kikkawa
Original assignee: Nippon Accumulator Co., Ltd.
Priority date: 2000-01-21
Filing date: 2001-04-13
Publication date: 2002-10-24
Also published as: JP2001208001A

Abstract

The pressure receiving surface (11A) of a stepped support (11) in a through-hole (10) in a container main body (1) is opposed to the pressing surface (14A) of the flange (14) of a supply and exhaust sleeve (13). When the flange (14) of the supply and exhaust sleeve (13) is loaded, it is deformed and the pressing surface (14A) is pressed against the pressure receiving surface (11A) to conform with the latter.

Description

Specification

Accumulator technical field

The present invention relates to an accumulator, and more particularly to an accumulator that must not be subjected to fatigue failure. Conventional technology

At the bottom of the container body of the accumulator, a supply / discharge cylinder through which the pressure liquid enters and exits is provided. The supply / discharge cylinder is fitted into the through hole at the bottom, and its flange is locked to a stepped receiving portion formed in the through hole.

When pressurized liquid is applied to the accumulator, a large force is applied to the flange portion of the supply / discharge cylinder. Therefore, the step-shaped receiving portion locked with the flange portion receives a large force. However, the pressure receiving surface of the step-shaped receiving portion abutting on the flange portion is formed in a substantially flat shape, and the load from the flange portion is received by the flat pressure receiving surface.

As a result, a large surface stress acts on the inner lower surface corner of the flange portion where the tensile force acts and the outer corner of the stepped receiving portion, and fatigue fracture occurs.

The present invention has been made in view of the above circumstances, and has as its object to prevent fatigue failure from occurring. Disclosure of the invention

An accumulator in which a through hole is provided at the bottom of the container body, and a supply / discharge cylinder is fitted into the through hole, and a flange portion of the supply / discharge cylinder is pressed against a stepped receiving portion of the through hole; The pressure receiving surface of the stepped receiving portion and the pressurizing surface of the flange portion of the supply / discharge cylinder are opposed to each other, and one of the two portions is deformed by a load applied to the flange portion so that one surface is deformed. Match with the other side.

For example, the pressure-receiving surface of the step-shaped receiving portion has an inner pressure-receiving surface formed along the diametric direction. And an outer pressure receiving R surface. The pressing surface of the flange portion includes: an inner pressing R surface facing the inner pressure receiving R surface; and an outer pressing R surface facing the outer pressure receiving R surface. The contact center angle between the inner R-faces of the two parts and the outer R-faces of the two parts is formed at 30 degrees, and is appropriately selected within a range of less than 70 ° as necessary. a brief description of that _c drawings

1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is an enlarged view of a main part of FIG. 1, FIG. 3 is a view showing another state of FIG. 2, FIG. 4 is an enlarged view of a main part of FIG. 5 is a longitudinal sectional view showing a comparative example, and is a view corresponding to FIG.

FIG. 6 is a longitudinal sectional view showing a second embodiment of the present invention, and corresponds to FIG.

FIG. 7 is a longitudinal sectional view showing a third embodiment of the present invention, and corresponds to FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Conventional accumulators are designed by calculating the surface pressure and calculating the pressure receiving surface in an area that does not cause plastic deformation.

In order to prevent stress concentration, it is conceivable to make the pressing surface and the pressure receiving surface that come into contact with each other R-shaped surfaces, but it is difficult to precisely process these R-surfaces as designed. Therefore, the present inventor has formed a pressurized surface and a pressure-receiving surface that face each other and have an R surface with materials having different hardnesses, and when the flange portion receives a load, the material with the smaller hardness is used. Plastic deformation or elastic deformation was performed to match the surface with the surface of another material with high hardness.

The surfaces of the pressurized and pressure-receiving surfaces that are pressed against each other are subjected to high compressive and tensile loads, causing fatigue failure. However, this fatigue failure does not occur even at high compressive loads, but does occur when tensile loads are applied repeatedly.

The present invention utilizes the above properties, and suppresses fatigue fracture by reducing the compressive load and the tensile load. Example 1

First Embodiment A first embodiment of the present invention will be described with reference to FIGS.

The accumulator ACC has a bladder 2 built in a container body 1. The bladder 2 is a so-called pleated bladder which is folded so as to be folded into a predetermined shape. The flange 3 of the bladder 2 is locked on the upper la of the container body 1 and is fixed by the lid 5. The lid 5 is provided with a supply / exhaust port 6 communicating with the inside of the bladder 2. A through hole 10 is provided in the bottom 1 b of the container body 1, and a supply / discharge cylinder 13 is inserted into the through hole 10. The flange portion 14 of the supply / discharge cylinder 13 is pressed against the stepped receiving portion 11 of the through hole 10.

The pressure-receiving surface 11A of the step-shaped receiving portion 11 includes an inner pressure-receiving surface 11a, a central pressure-receiving surface 11b, and an outer pressure-receiving surface 11c, which are successively arranged in the radial direction.

Radius of the inner pressure R surface 11 a is, for example, 3.2 thigh, radius R ₂ of the outer pressure bearing R surface 11 c is formed, for example, 1.8 Hall. The inclined surface 11 d continuous to the inner pressure receiving R surface 1 la is inclined, for example, by 20 ° with respect to the center line 10 c of the through hole 10. The supply / discharge cylinder 13 is formed of a material having a lower hardness than the material of the stepped receiving portion 11, and the pressurizing surface 14 A of the flange portion 14 of the supply / discharge cylinder 13 has a gap with the inner pressure receiving R surface 11 a. The inner pressure R surface 14a opposing through t, the central pressure surface 14b pressed against the central pressure receiving surface 11b, and the outer pressure surface facing the outer pressure receiving surface 11c via the gap t. Pressure R surface 14c.

Radius R ₃ of the inner pressure R surface 14 a is, for example, 3 mm, the radius R ₄ of the outer pressure R surfaces 14c, for example, is formed in two thigh. The center of the radius R !, R _3, it it is located on the center line 10 c and the parallel line L3 transmembrane throughbore 10, also center of the said radius R _2, R ₄ are each through hole 10 Is located on a straight line L4 parallel to the center line 10c of. A povet valve 16 with a cushion cap 15 is slidably supported on the supply / discharge cylinder 13. The supply / discharge cylinder 13 is fixed to the container body 1 by a nut 17. Next, the operation of the present embodiment will be described.

When the hydraulic pressure of the hydraulic circuit connected to the accumulator changes and the accumulator is pressurized, the supply / discharge cylinder 13 is pressed in the direction of arrow A13, and the central pressurization is performed as shown in FIGS. 3 and 4. The plane 14b is plastically deformed while being elastically deformed by being pressed against the central pressure receiving plane 11b.

Next, the inner pressurized R surface 14a and the outer pressurized R surface 14c also come into pressure contact with the opposing inner pressurized R surface 1la and outer pressurized R surface 1lc, respectively, and undergo plastic deformation while being elastically deformed. When the applied force and the deformation force are balanced, the deformation does not progress. In this case, the two R surfaces 11 a of the inner both parts, 14 a of the contact center angle 0I, the contact center angle 0 ₂ of the two R surfaces 11 c, 14 c of the outer surfaces of the parts, is less than 70 ° For example, the central angle 0 ₂ is 30 ° each. In addition, this R surface can receive more than 50% of the load. The radius of the inner pressurized R surface 14a changes to R3a as shown in FIG.

As described above, the central pressure plane 14b, the inner and outer pressure R-faces 14a, 14c can easily conform to the central pressure-receiving plane 11b, the inner and outer pressure-receiving R faces 11a, 11c. It is transformed into a shape. The total load applied to the flange portion 14 is shared by the central pressure receiving plane 11b, the inner pressure receiving R surface 11a, and the outer pressure receiving R surface 11c.

At this time, a tensile load is applied to the inner pressurized R surface 14a of the flange portion 14 and the outer pressurized R surface 11c of the stepped receiving portion 11.

When the tensile load of the accumulator of this embodiment is calculated by the finite element method, when the total load applied to the flange portion 14 is set to 332 and 62 ON, the maximum internal load of the flange portion 14 The maximum tensile load of the R surface 14a is 405NZ顧^2, also, the maximum tensile load of the outer pressure R surface 11 c of the stepped sockets 11 was 48 lNZmm ^2.

On the other hand, as shown in Fig. 5, the radius R2 of the outer pressure receiving R surface 1 lc is 0.8 thigh, the radius R4 of the outer pressing R surface 14c is 0.8, and the radius of the inner pressing R surface 14a is 0.8. R ₃ is 1.2 fiber, inner pressure is R radius of 11a is 0.4 thigh, slope angle of 1 d is 15 °, and the same load is applied to flange 14 as above. Finite element Analysis. As a result, the maximum tensile load of the inner pressurized R surface 14 a of the flange portion 14 was 79 ON / thigh ² , and the maximum tensile load of the outer pressurized R surface 11 c was 87 1 N / thigh ² . When a pressure of l / 3 Hz, a maximum pressurizing force of 47.9 to 48.3 & a minimum pressing force of 0.1 to 0.3 MPa was applied to both accumulators, the accumulator shown in Fig. 2 failed even after 1,000,000 operation tests. However, the accumulator in Fig. 5 had fatigue failures at 326 and 550 times.

As is evident from the above, if the contact center area of the R surface is increased to increase the pressure receiving area, the load is dispersed and the tensile load applied to the pressurized R surface is reduced, so that it is possible to prevent the occurrence of fatigue fracture. it can. Example 2

Second Embodiment A second embodiment of the present invention will be described with reference to FIG.

The difference between this embodiment and the first embodiment (FIGS. 1 to 5) is that the central pressure plane and the central pressure receiving plane are omitted. That is,

The inner pressurized R surface 14a and the outer pressurized R surface 14c are directly continuous, and the inner pressurized R surface 11a and the outer pressurized R surface 11c are directly connected, This means that the entire load acting on the flange portion 14 is received on this R surface.

The center of radius 1 ^ to 1 ₄ are located in the through hole 1 0 centerline 1 0 c parallel collinear L. Example 3

Third Embodiment A third embodiment of the present invention will be described with reference to FIG.

The difference between this embodiment and the first embodiment (FIGS. 1 to 5) is that the center pressurized curved surface 14 d and the central pressurized curved surface 11 d are replaced with the central pressurized flat surface and the central pressurized flat surface. It is provided. That is,

The inner pressurized R surface 14a and the outer pressurized R surface 14c are connected via the central pressurized curved surface 14d, and the inner pressurized R surface 11a and the outer pressurized R surface 1 1 c is the central pressure receiving surface Connected via 1 1 d.

The centers of the radii R t and R ₃ are located on the same straight line 1 ^ parallel to the center line 10 c of the through hole 10, and the centers of the radii R ₂ and R ₄ are the centers of the through holes 10 It is located on line 1 0 c parallel same straight line L _2. The invention's effect

The present invention has the following remarkable effects. That is,

(1) Since one of the flange portion and the stepped receiving portion is deformed by the load applied to the flange portion to make one surface thereof coincide with the other surface, both surfaces can be easily brought into close contact with each other. Therefore, the opposing R surfaces can be easily brought into close contact without processing the R surface precisely.

(2) The contact center angle between the inner R-faces inside the two parts and the contact center angle between the outer R-faces outside the two parts were each smaller than 70 °. It becomes smaller and the compressive stress per unit area increases, causing elastic deformation and plastic deformation. In addition, since a large radius surface receives a force, the surface tensile stress is dispersed and reduced, so that fatigue fracture hardly occurs. As a result, the service life is extended, and the accumule can be used semi-permanently.

Claims

The scope of the claims

1. An accumulator in which a through hole is provided at the bottom of the container body, and a supply / discharge cylinder is fitted into the through hole, and a flange portion of the supply / discharge cylinder is pressed against a stepped receiving portion of the through hole; The pressure receiving surface of the stepped receiving portion and the pressing surface of the flange portion of the supply / discharge cylinder are opposed to each other, and one of the two portions is deformed by a load applied to the flange portion to deform one of the two portions. Accumure night, characterized by matching with the other side.

2. The pressure receiving surface of the stepped receiving portion includes an inner pressure receiving R surface and an outer pressure receiving R surface formed along a diametric direction, and the pressing surface of the flange portion is formed on the inner pressure receiving R surface. 2. The accumulator according to claim 1, further comprising: an opposed inner pressurized R surface, and an outer pressurized R surface facing the outer pressure receiving R surface.

3. The pressure receiving surface of the stepped receiving portion includes an inner pressure receiving R surface, a central pressure receiving curved surface, and an outer pressure receiving R surface that are successively arranged in a diametrical direction, and the pressing surface of the flange portion is the inner pressure receiving surface. An inner pressure R surface facing the R surface, a central pressure curved surface facing the central pressure receiving plane, and an outer pressure R surface facing the outer pressure reception R surface. The accumulator according to item 1.

4. The contact center angle between the inside R-faces of the two parts and the contact center angle between the outside R-faces of the two parts are less than 70 °, respectively. Accumulator according to 3.

5. The accumulator according to claim 1, wherein the deformation is plastic deformation or elastic deformation.

6. The accumulator according to claim 2, wherein the radius of curvature of the inner pressure receiving R surface is smaller than that of the inner pressure receiving R surface.