JP2001208001A - Accumulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an accumulator which prevents fatigue fracture. SOLUTION: The stepwise receiving part 11 of through-hole 10 in a vessel body has a pressure inside curved surface 11a a pressure central plane 11b and a pressure outside curved surface 11c which are continuously formed along a diameter direction. The flange 14 of a supplying/exhausting cylinder 13 is provided with a pressurized inside curved surface 14a, a pressurized central plane 14b and a pressurized outside curved surface 14c which are brought into press contact with the above surface 11a, plane 11b and surface 11c, respectively. The central contact angles of both inside curved surfaces 11a and 14a, and of both outside curved surfaces 11c and 14c are formed to be less than 70 degrees.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accumulator, and more particularly to an accumulator which must not be damaged by fatigue.

[0002]

2. Description of the Related Art At the bottom of an accumulator container body,
A supply / discharge cylinder through which the pressure liquid enters and exits is provided. The supply / discharge cylinder is fitted in a through hole in the bottom portion, and a flange portion thereof is locked by a step-shaped receiving portion formed in the through hole.

[0003]

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.

[0004] However, the pressure receiving surface of the stepped 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. for that reason,
A large surface tensile stress acts on the inner lower surface corner of the flange portion and the outer corner of the stepped receiving portion on which a tensile force acts, so that fatigue fracture occurs.

[0005] In view of the above circumstances, an object of the present invention is to prevent the occurrence of fatigue failure.

[0006]

According to the present invention, a through hole is provided in a bottom portion of a container body, and a supply / discharge cylinder is fitted into the through hole, and a flange of the supply / discharge cylinder is fitted to a stepped receiving portion of the through hole. A pressure receiving surface of the stepped receiving portion of the through hole includes an inner pressure receiving R surface and an outer pressure receiving R surface formed along a diametrical direction, and a flange of the supply / discharge cylinder. The pressurizing surface of the portion, an inner pressurized R surface facing the inner pressurized R surface,
An outer pressurized R surface facing the outer pressurized R surface, wherein one of the two portions is deformed by a load applied to the flange portion so that one surface coincides with the other surface. Features.

According to the present invention, there is provided an accumulator in which a through hole is provided in a bottom portion of a container body, 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. Wherein the pressure receiving surface of the stepped receiving portion of the through hole has an inner pressure receiving R surface, a central pressure receiving slope, and an outer pressure receiving R surface that are successively arranged in a diametrical direction. A pressurizing surface, an inner pressurized R surface facing the inner pressurized R surface,
A central pressurized slope facing the central pressure-receiving slope, and an outer pressurized R-face opposed to the outer pressure-receiving R-face, wherein one of the two portions is deformed by a load applied to the flange portion. In this case, one surface is made to coincide with the other surface.

According to the present invention, there is provided an accumulator in which a through hole is provided in a bottom portion of a container body, 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. Wherein the pressure receiving surface of the stepped receiving portion of the through hole includes an inner pressure receiving surface, a central pressure receiving surface, and an outer pressure receiving surface that are successively arranged in a diametrical direction. The pressurizing surface is an inner pressurized R surface opposed to the inner pressure receiving R surface via a gap, a central pressurized plane opposed to the central pressure receiving plane via a gap, and a pressurized surface facing the outer pressure receiving R surface. An opposing outer pressurized R surface, wherein one of the two portions is deformed by a load applied to the flange portion so that one surface coincides with the other surface. The center angle of contact between the surfaces and the center angle of contact between the R surfaces outside the both parts are respectively Be less than 70 °, characterized in that for receiving a load of 50% or more in the R-plane.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a conventional accumulator, a pressure receiving surface is calculated and a pressure receiving surface is calculated by an area which does not cause plastic deformation. Further, in order to prevent stress concentration, it is conceivable to make the pressurized surface and the pressure-receiving surface that are in contact with each other an R surface, but it is difficult to precisely process the R surface as designed.

Therefore, the inventor of the present invention has formed a pressing face and a pressure receiving face which face each other and have an R surface with materials having different hardnesses, and when a load is applied to the flange portion, the smaller hardness is used. The material is plastically or elastically deformed so that its surface matches the surface of another material having high hardness.

[0011] The surfaces of the pressure surface and the pressure receiving surface that are pressed against each other are:
High compressive load and high tensile load cause fatigue fracture. However, this fatigue fracture does not occur even when the compression load is high, but it occurs when a high tensile load is repeatedly applied. The present invention utilizes the above-mentioned properties, and suppresses fatigue fracture by reducing a compressive load and a tensile load.

According to the present invention, a stepped receiving portion is formed in a through hole in a bottom portion of a container body, and an inner pressure receiving surface, a central pressure receiving surface, and an outer pressure receiving R surface which are successively successive in the stepwise receiving portion along a diametrical direction. And an inner pressurized R surface that presses against the flange portion of the supply / discharge cylinder with the inner pressure receiving R surface, a central pressurizing surface that presses against the central pressure receiving surface, and an outer pressurizing R that presses against the outer pressure receiving R surface. Form a surface.

The center angle of contact between the inner R-faces of the two portions and the outer R-face of the two portions is formed, for example, at 30 degrees, but is appropriately selected within a range of less than 70 ° as necessary. Is done. In this case, the radius of curvature can be made larger than that of the conventional example, so that the shape deformation becomes gentle and the stress can be dispersed. In addition, since the length of the arm receiving the force can be shortened, the bending moment is also reduced.

The central pressure plane and the central pressure receiving plane may be replaced with a central pressure slope and a central pressure receiving slope.

Further, the central pressure plane and the central pressure receiving plane may be omitted. That is, the pressure receiving surface of the stepped receiving portion is constituted by an inner pressure receiving R surface and an outer pressure receiving R surface that are continuous in a diametrical direction, and the pressing surface of the flange portion is opposed to the inner pressure receiving R surface via a gap. An inner pressurized R surface, and an outer pressurized R surface opposed to the outer pressure receiving R surface via a gap, and a contact center angle between the inner R surfaces inside the both portions and an outer pressurized surface outside the both portions. The contact center angles of the R-planes may each be set to an area of less than 70 ° to receive the entire load. When all the loads are received on the R-plane as described above, the shape deformation becomes gentle and the stress is dispersed, so that the accumulator becomes more resistant to fatigue.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The accumulator ACC has a bladder 2 in the container body 1.
Built-in. 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
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 1b 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 stepped receiving portion 11 has an inner pressure receiving surface 11a, a central pressure receiving surface 11b, and an outer pressure receiving R surface 11c that are successively arranged in the diametrical direction. Radius R ₁ of the inner pressure-receiving R surface 11a, for example, 3.2 mm, the radius R ₂ of the outer pressure-receiving R surface 11c is formed, for example, to 1.8 mm. The inclined surface 11d continuous with the inner pressure receiving R surface 11a is inclined by α, for example, 20 ° with respect to the center line 10c 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. The pressing surface 14 P of the flange portion 14 of the supply / discharge cylinder 13 is
a and an inner pressurized R surface 14a opposed to the central pressurizing surface 11b via a gap t,
And an outer pressurized R surface 14c opposed to the outer pressure receiving R surface 11c via a gap t.

The radius R ₃ of the inner pressing R surface 14a is, for example, 3 mm, and the radius R ₄ of the outer pressing R surface 14c is, for example,
It is formed to 2 mm. The centers of the radii R ₁ and R ₃ are located on a straight line L3 parallel to the center line 10C of the through hole 10, and the centers of the radii R ₂ and R ₄ are respectively
0 is located on a straight line L4 parallel to the center line 10C.

A poppet valve 16 with a cushion cup 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 this 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 moves to the direction indicated by the arrow A.
As shown in FIGS. 3 and 4, the central pressing plane 14b is pressed against the central pressure receiving plane 11b and plastically deforms while being elastically deformed.

Next, the inner pressurized R surface 14a and the outer pressurized R
The surface 14c also comes into pressure contact with the opposing inner pressure receiving R surface 11a and outer pressure receiving R surface 11c, and undergoes plastic deformation while being elastically deformed.

When the pressing force and the deforming force are balanced, the deformation does not progress. At this time, the contact center angle θ ₁ between the two R surfaces 11a and 14a inside the two portions,
The contact center angle θ between the two R surfaces 11c and 14c outside the both portions
₂ is less than 70 °, for example, the central angles θ ₁ and θ ₂ are each 30 °. Also, a load of 50% or more can be received on this R surface. As shown in FIG. 4, the radius of the inner pressurized R surface 14a is R ₃
changes to a.

As described above, the central pressure plane 14b and the inner and outer pressure receiving R-faces 14a, 14c easily conform to the central pressure receiving plane 11b, the inner and outer pressure-receiving R faces 11a, 11c, and are made pudding. The total load applied to the flange portion 14 is shared by the central pressure receiving flat surface 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, the flange 1
Assuming that the total load applied to No. 4 is 332 and 620 N, the maximum tensile load of the inner pressurized R surface 14 a of the flange portion 14 is 4
05N / mm ² , and the maximum tensile load of the outer pressure receiving R surface 11c of the stepped receiving portion 11 was 481 N / mm ² .

On the other hand, an accumulator of a comparative example as shown in FIG. 5 was formed, and the case where the same load was applied to the flange portion 14 of this accumulator was analyzed by the finite element method. In this comparative example, the outer pressure receiving R surface 11c
Radius R2 of the outer pressurized R surface 14c is 0.8 mm.
formed in mm, the radius R ₃ Ha 1.2mm of the inner pressure R surfaces 14a,
The radius R ₁ of the inner pressure receiving R surface 11a is 0.4 mm, and the inclination angle α of the inclined surface 11d is 15 °.

As a result, the maximum tensile load on the inner pressurized R surface 14a of the flange portion 14 was 790 N / mm ² , and the maximum tensile load on the outer pressurized R surface 11c was 871 N / mm ² .

When a pressure of 1/3 HZ, a maximum pressure of 47.9-48.3 MPa, and a minimum pressure of 0.1-0.3 MPa was applied to both accumulators, the accumulator of FIG.
The accumulator in FIG. 5 failed in 326,550 cycles, although it did not break in 000 operation tests.

As is clear from this, when the R surface is brought into contact and receives a load of 50% or more, the contact surface pressure on the R surface increases, but the tensile stress can be reduced, thereby preventing the occurrence of fatigue fracture. be able to.

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 pressing plane portion 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
a and the outer pressure receiving R surface 11c are directly connected, and the entire load applied to the flange portion 14 is received on the R surface. The centers of the radii R _{1 to} R ₄ are located on the same straight line L parallel to the center line 10 c of the through hole 10.

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 a center pressurizing slope 14d and a central pressure receiving slope 11d are provided instead of the center pressurizing plane portion and the center pressure receiving plane. It is. That is, the inner pressure R surface 14a and the outer pressure R
The surface 14c is continuous through a central pressure slope 14d, and the inner pressure receiving surface 11a and the outer pressure receiving surface 11c are connected via a central pressure receiving surface 11d. The centers of the radii R ₁ and R ₃ are located on the same straight line L 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 parallel to the center line 10 c of the through hole 10. It is located on the same straight line L ₂ a.

[0034]

The present invention has the following effects. (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, even if the R surface is not precisely machined,
Opposing R surfaces can be easily brought into close contact with each other.

(2) The contact center angle between the inner R surfaces inside the two portions and the contact center angle between the outer R surfaces outside the both portions are each smaller than 70 °. The area becomes smaller and the compressive stress per unit area becomes larger, causing elastic deformation or plastic deformation. At this time, a high compression load is also applied to the R surface, but the deformation is generated in a wide portion because the thickness change can be gradual due to the large R surface. Therefore,
Since the tensile stress is dispersed and the tensile stress is reduced, fatigue fracture hardly occurs. Therefore, the service life can be extended.

[Brief description of the drawings]

FIG. 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.

FIG. 3 is a diagram showing another state of FIG. 2;

FIG. 4 is an enlarged view of a main part of FIG. 3;

FIG. 5 is a longitudinal sectional view showing a comparative example, and is a view corresponding to FIG. 2;

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

FIG. 7 is a longitudinal sectional view showing a third embodiment of the present invention, and is a view corresponding to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container main body 10 Through-hole 11 Step-shaped receiving part 11a Inner pressure receiving R surface 11b Central pressure receiving surface 11c Outer pressure receiving R surface 13 Supply / discharge cylinder 14 Flange part 14a Inner pressurized R surface 14b Central pressurized flat surface 14c Outer pressurized R surface

Claims (5)

[Claims] 1. An accumulator wherein a through hole is provided in a bottom portion of a container body, 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 of the through hole includes an inner pressure receiving R surface and an outer pressure receiving R surface formed along a diametrical direction, and the pressing surface of the flange portion of the supply / discharge cylinder includes the inner pressure receiving surface. An inner pressurized R surface facing the pressure receiving R surface, and an outer pressurized R surface facing the outer pressure receiving R surface, wherein one of the two portions is deformed by a load applied to the flange portion. An accumulator characterized in that one surface coincides with the other surface. 2. An accumulator wherein a through hole is provided in a bottom portion of a container body, 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 of the through hole includes an inner pressure receiving R surface, a central pressure receiving slope, and an outer pressure receiving R surface that are successively arranged in a diametrical direction, and a pressing surface of the flange portion of the supply / discharge cylinder. Has an inner pressurized R surface facing the inner pressurized R surface, a central pressurized slope opposing the central pressurized slope, and an outer pressurized R surface opposing the outer pressurized R surface, An accumulator characterized in that one of the two portions is deformed by a load applied to the flange portion so that one surface coincides with the other surface. 3. An accumulator in which a through hole is provided in a bottom portion of a container body, 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 of the through hole includes an inner pressure-receiving surface, a center pressure-receiving surface, and an outer pressure-receiving surface that are successively arranged in a diametric direction, and a pressing surface of a flange portion of the supply / discharge cylinder. Has an inner pressurized R surface facing the inner pressurized R surface, a central pressurized plane facing the central pressurized plane, and an outer pressurized R surface facing the outer pressurized R surface, The load applied to the flange portion deforms one of the two portions so that one surface coincides with the other surface, and the contact center angle between the R surfaces inside the two portions and the R outside the two portions. The center angles of contact between the surfaces must be less than 70 °, and a load of 50% or more is received on the R surface. Accumulator, characterized in that. 4. The accumulator according to claim 1, wherein the deformation is plastic deformation or elastic deformation. 5. The accumulator according to claim 1, wherein the radius of curvature of the inner pressure receiving R surface is smaller than that of the inner pressure receiving R surface.