JPH03129173A - Accumulator and its manufacture - Google Patents

Abstract

PURPOSE:To acquire a stable welded part of better than a specific quality by processing and polymerizing a bellows body after squeezing it by the amount of one wrinkle or a plural number of wrinkles from the end of the bellows body in the axial line direction. CONSTITUTION:A wrinkle 30e at the end part of a bellows body 30 is press worked and an end polymerized part 41 is made. The thickness t1 of this polymerized part 41 becomes approximately two times the plate thickness t0 of the bellows body 30. Moreover, a bent outer peripheral edge 42 becomes a smoothly curved shape without flash. The outer diameter D1 of a bellows base 31 is made about 0.5mm larger than the outer diameter D0 of the end polymerized part 41. At the time when the bellows body 30 and the bellows base 31 are held in the axial direction with jigs 50, 51, and by rotating the both jigs 50, 51, the body 30 and the base 31 together, the bent outer peripheral edge 42 and an end outer peripheral part 45 are welded all over their periphery. In this case, the thickness L2 of the end outer peripheral part 45 of the base 31 is made near to the thickness t1 of the end polymerized part 41 of the body 30 by way of providing a V shape recessed part 36.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an accumulator used in, for example, a pneumatic suspension device or a pulsation absorbing device, and a method for manufacturing this accumulator.

[Prior Art] In an accumulator in which hydraulic fluid and compressed gas are housed inside a sealed housing, a metal bellows may be built in to partition the hydraulic fluid and gas.

The metal bellows for accumulators developed by the present inventors includes a metal bellows body with a plate thickness of about 0.1 to 0.25++v, a bellows base welded to one end of the bellows body, and the other end of the bellows body. It is constructed with a bellows cap that is welded to the The bellows base is fixed to the accumulator housing.

To fix the bellows body and bellows base by conventional welding techniques, for example, as shown in FIG.
A short cylindrical portion 103 is provided at the open end 102 of the bellows body 101, and a hole 10 is provided in the bellows base 104.
5 is provided, and after fitting the portion 103 into the hole 105, the edge 10B of the hole 105 and the edge 107 of the bellows body 101 are welded together over the entire circumference.

Alternatively, in another conventional method shown in FIG.
After fitting the bellows base 104 inside the enlarged diameter part 110, the end edge 107 of the bellows body lO1 and the edge 111 of the bellows base 104 are fully connected to each other. I try to weld it all the way around.

On the other hand, the welding between the bellows cap and the bellows body is
As illustrated in FIG. 12, the edge l16 of the open end 115 of the bellows body lO1 is formed into a flange shape, and the base H8 of the bellows cap 117 is fitted inside the open end 115. and bellows cap 117
are welded together around the entire circumference.

￥S13 In another conventional method shown in FIG. Bellows cap 117
After fitting the base portion 11B of the expanded diameter portion 120,
21 and the bellows cap 117 are welded together over the entire circumference.

[Problems to be Solved by the Invention] In each of the above-mentioned conventional examples, the bellows body 10
1 open end 102, bellows base 104 at 11'5
Alternatively, it is a structure in which a bellows cap 117 is fitted. Therefore, the fitting portion between the open end 102 and the bellows base 104 and the fitting portion between the open end H5 and the cap 117 must be precisely machined. In addition, the edges 107, 118, 121 of the bellows body 101 must be cut into an accurate shape so that there are no "bumps". Moreover, the thickness of the bellows body 101 is 0. (
It is as thin as 0.25 mm.

For these reasons, it is difficult to ensure a welded part of a certain quality or higher using conventional welding techniques. Poor quality welds mean that the bellows cannot be sufficiently airtight and durable.

Therefore, an object of the present invention is to provide a method for attaching a metal bellows that can obtain a stable welded part of a certain quality or higher when welding a bellows attachment member such as a bellows base or a bellows cap to a bellows body, and to provide a method for installing the metal bellows. The objective is to provide an accumulator with a built-in.

[Means for Solving the Problems] In order to achieve the above object, the accumulator bellows developed by the present inventor includes a metal bellows body in which pleats are formed by plastic working and whose edges face toward the center of the bellows; The bellows base includes a metal bellows base connected to one open end of the bellows body, and a metal bellows cap connected to the other open end of the bellows body to close the open end, and the bellows cap is connected to the bellows base. At the connection part of the body, one or more folds from the end of the bellows body are crushed in the axial direction and then polymerized to make the thickness of this end overlapping part greater than the plate thickness of the bellows body, and this end overlapping part is The outer peripheral edge of the bellows body and the outer peripheral part of the bellows body are welded to each other over the entire circumference, and at the connection part between the bellows cap and the bellows body, one or more folds are crushed in the axial direction from the end of the bellows body. The thickness of this end overlapping portion is made to be at least twice the plate thickness of the bellows body by polymerization, and the outer peripheral edge of this end overlapping portion and the outer peripheral portion of the bellows cap are welded to each other over the entire circumference.

Furthermore, the method for manufacturing an accumulator of the present invention includes a metal bellows body having pleats formed by plastic working and whose edges face toward the center of the bellows, and a metal bellows base or bellows welded to the open end of the bellows body. When manufacturing a bellows with a bellows attachment member such as a cap, by crushing the ends of the bellows body in the axial direction by one or more folds and polymerizing, the thickness of the end overlapped portion can be reduced to the thickness of the bellows body. The bellows attachment member is fixed to the bellows body by welding the outer peripheral edge of the terminal overlapping portion and the outer peripheral portion of the bellows attachment member to each other over the entire circumference.

[Working Since the end overlap portion of the bellows body has a thickness equal to at least two plate thicknesses of the bellows body, the thickness necessary for stable welding is ensured. Moreover, the outer peripheral edge of the terminal overlapping portion is smoothly bent into four curves so that the cross section along the axial direction is approximately semicircular. Therefore, there will be no "bumps" appearing on the outside of the area to be welded.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

The accumulator 10 shown in FIG. 7 includes a sealed cylindrical housing 11, a bellows 12 and an inner cylinder 13 housed inside the housing 11. The housing 11, the bellows 12, and the inner cylinder 13 are arranged concentrically with each other.

A compressed inert gas is sealed inside an air chamber 16 defined by the inner surface of the housing 11 and the outer surface of the bellows 12. An example of an inert gas is nitrogen. A liquid chamber 17 defined by the inner surface of the bellows 12 is filled with oil as an example of hydraulic fluid.

The housing 11 includes a right cylindrical housing body 20 having both ends, and a first housing body 20 that closes one end of the housing body 20.
It consists of an end member 21 and a second end member 22 that closes the other end of the housing body 20. A liquid circulation boat 23 is provided on the first end member 21 . This boat 23 communicates with the liquid chamber 17.

The second end member 22 is provided with a boat 24 that is used to supply the gas to the air chamber 16.

After the air chamber 16 is filled with gas, the boat 24 is closed with a plug 25.

The bellows 12 includes a metal bellows body 30 having both ends 30a and 30b, a metal bellows base 31 to which one end 30a of the bellows body 30 is welded, and a metal bellows base 31 welded to the other end 30b of the bellows body 30. a bellows cap 32; a first synthetic resin guide ring 33 attached near the bellows cap 32;
The second bellows body 30 is attached to an axially intermediate portion of the bellows body 30.
The guide ring 34 is made of synthetic resin. These guide rings 33, 34 are slidably in contact with the inner peripheral surface of the housing 11.

The bellows body 30 has a plurality of folds 35 formed in the axial direction by plastic working such as hydraulic forming or roll forming. In FIG. 1, T indicates the axial dimension of the pleats 35, and P indicates the pitch of the pleats 35. Edges 3oc and 30d of the bellows body 30 face toward the center of the bellows body 30. The bellows body 30 is expandable and retractable in the axial direction of the housing 11. The bellows base 31 is fixed to the first end member 21 of the housing 11 by suitable fixing means.

First, the connection between the bellows body 30 and the bellows base 31 will be explained. An example of the bellows base 31 is the first
As shown in the figure. A recess 36 having a V-shaped cross section is provided on the outer periphery of the bellows base 31. This recess 36 is continuous over the entire circumference of the bellows base 31.

The angle θ1 formed by the slope 37 of the recess 36 is 45''. The depth Ll of the recess 36 is l, 50±0.20+am.

The distance L2 from the edge 38 to the edge 39 of the recess 36 is 0.3
5±0.05mm.

Plate thickness t of bellows body 30. is 0.1~0.25mm
It is. In this embodiment, the bellows body 30 and the bellows base 31 are made of, for example, stainless steel. However, the body 30 and the base 31 may be made of metals other than those mentioned above. Also, body 30 and base 31
do not necessarily have to be the same metal.

As shown in FIG. 2, the folds 30e at the end of the bellows body 30 are crushed by one fold in the axial direction by press working to form an end overlapping part 41. The thickness tl of this terminal overlapping portion 41 is the plate thickness t of the bellows body 30.

It will be almost twice as much.

Moreover, the bent outer peripheral edge 42 of this terminal overlapping portion 41 has a substantially semicircular cross section along the axial direction, that is, a "bori" shape.
It has a smoothly curved shape with no protrusions. Note that the terminal overlapping portion 41 may be formed by collapsing a plurality of pleats in the axial direction.

The outer diameter D1 of the bellows base 31 is the outer diameter of the terminal overlapping portion 41. It is made about 0.5 mm larger than that. In the case of this embodiment, a part of the outer end portion 45 of the bellows base 31 is melted by TIG welding in an argon gas atmosphere,
Cover the bent outer peripheral edge 42. No filler is used during this welding, and welding is done by tanning. It should be noted that the appropriate difference between Dl and Do is 0.5■, but values other than this may be better depending on the relationship with the welding conditions.

As conceptually shown in FIG.
When welding the bellows base 31, the jigs 50, 51
The bellows body 30 and bellows base 31 are pressed in the axial direction. The pressing force of the jig 50.51 at this time is
The size is such that the bellows body 30 and the bellows base 31 are in close contact with each other.

While rotating the bellows body 30 and bellows base 31 together with the jigs 50 and 51, the bent outer peripheral edge 42 and the terminal outer peripheral part 45 are welded over the entire circumference. The bellows base 31 of this embodiment has a V-shaped recess 36 (groove) so that the thickness L2 of the end outer circumferential portion 45 is made close to the thickness tl of the end overlapping portion 41 of the bellows body 30. Therefore, during welding, the heat capacities of the bent outer circumferential edge 42 and the end outer circumferential portion 45 are balanced with each other, so that welding can be performed satisfactorily.

Note that the thickness of the bellows base 31 itself is terminal type.

When the thickness of the joining portion 41 is close to t2, the bent outer peripheral edge 42 and the terminal outer peripheral portion 45 may be welded to each other without providing the V-shaped recess 36.

On the other hand, the connection between the bellows cap 32 and the bellows body 30 is as follows. An example of the bellows cap 32 is shown in FIG. The bellows cap 32 is formed in a tapered shape such that its entire circumference gradually decreases in thickness toward the terminal outer circumferential portion 60. The inclination angle θ2 of the tapered surface 61 is 45°, and the thickness L3 of the terminal outer peripheral portion 60 is 0.35±0.0.
It is 5m+g. In the case of this embodiment, the bellows body 30
The same metal is used for the bellows cap 32. however,
Different metals may be used for the body 30 and the cap 32.

As shown in FIG. 5, the end overlap portion 63 is created by crushing the folds 30f at the end of the bellows body 30 by one fold in the axial direction of the body 30 using a press.

The thickness t3 of the terminal overlapping portion 63 is the plate thickness t of the bellows body 30. It will be almost twice as much. Moreover, the bent outer circumferential edge 64 of this terminal overlapping portion 63 has a substantially semicircular cross section along the axial direction, that is, a smoothly curved shape without a "bump". Note that the terminal overlapping portion 63 may be formed by collapsing a plurality of pleats in the axial direction.

The outer diameter D2 of the bellows cap 32 is equal to the outer diameter D2 of the bellows body 3.
0 outer diameter. It is made about 0.5 mm larger than that. Then, a part of the end outer circumferential portion 60 of the baize cap 32 is melted by TIG welding in an argon gas atmosphere, and the bent outer circumferential edge 64 is covered. In addition, take D2. The difference is 0.
5w+g is appropriate, but values other than this may be possible depending on the relationship with the welding conditions.

During the above welding, as conceptually shown in FIG. 6, the bellows body 30 and the bellows cap 32 are attached to a jig 50.
51 in the axial direction.

The pressing force of the jigs 50 and 51 is such that the bellows body 30 and the bellows cap 32 come into close contact with each other.

While rotating the bellows body 30 and bellows cap 32 together with the jigs 50 and 51, the terminal outer peripheral portion 60 and the bent outer peripheral edge 64 are welded over the entire circumference. The thickness of the terminal outer periphery 6o in this embodiment is made closer to the thickness t of the bent outer periphery 64 by providing the tapered surface 61, so that the bent outer periphery 64 and the terminal outer periphery 6o during welding. By balancing the heat capacities of the welds, high-quality welding can be achieved.

Note that the thickness of the bellows cap 32 itself is greater than the thickness of the end overlapping portion 6.
If the thickness is close to t, the bent outer peripheral edge 64 and the terminal outer peripheral portion 60 may be welded to each other without providing the tapered surface 61.

FIG. 8 shows a modification of the end overlapping portion 41°63 of the bellows body 30. In this case, the terminal overlapping portion 41.
63 (7) Inner peripheral edges 30c, 30d are outer peripheral edges 42.64
An overhanging angle α is provided in each case so as to retract inward in the axial direction. By doing this,
During welding, the outer circumferential edge 42. to the terminal outer circumferential portion 45.60.
The adhesion of 64 is improved. The preferred value of α is 3° to 10
'is. Then, the outer peripheral edge 42.64 is connected to the bellows base 31.
or the outer end periphery 60 of the bellows cap 32.

FIG. 9 shows yet another modification of the terminal overlapping portion 41.63. In the case of this modification, the same angle α as above is provided on the inner peripheral edges 30c and 30d of the overlapping portion 41°63, and a flat portion 70.71 parallel to the pleats 35 is provided on the outer peripheral edge 42.64 side. It is set up.

And the bent outer peripheral edge 42°64 of this flat part 70.71
is welded to the bellows base 31 or bellows cap 32.

[Effects of the Invention] According to the present invention, the quality of the welded portion between the bellows body and the bellows attachment members such as the base and cap welded to the bellows body is improved, and an accumulator with excellent airtightness and durability is obtained. It will be done.

[Brief explanation of the drawing]

1 to 7 show one embodiment of the present invention, in which FIG. 1 is a sectional view showing the connection between the bellows body and the bellows base, FIG. 2 is a sectional view showing the end of the bellows body, and FIG. 3 is a side view showing a suppression jig used during welding, FIG. 4 is a sectional view showing the connection between the bellows body and the bellows cap, and FIG. 5 is a sectional view showing the end of the bellows body.
Figure 6 is a side view showing the pressing jig used during welding, Figure 7
The figure is a longitudinal cross-sectional view of an accumulator with a built-in bellows, Figures 8 and 9 are cross-sectional views showing modified examples of the ends of the bellows body, and Figures 10 to 13 are respectively the connection parts of conventional bellows. FIG. 10...Accumulator, 11...Housing, 1
2... Bellows, 16... Air chamber, 30... Bellows body, 31... Bellows base, 32... Bellows cap, 35... Fold, 41... Terminal overlapping part, 42... ... Outer periphery, 50.51 ... Pressing jig, 6
3... Terminal overlapping part, 64... Outer periphery.

Claims (4)

[Claims] (1) In an accumulator including a cylindrical metal housing and a bellows housed inside the housing, one end of which is fixed and the other end is expandable and contractible in the axial direction of the housing, the bellows is folded by plastic working. A metal bellows body having a molded shape and an edge facing toward the center of the bellows, a metal bellows base to which one open end of the bellows body is connected, and a metal bellows base connected to the other open end of the bellows body. It includes a metal bellows cap that closes this opening end, and at the connection part of the bellows body to the bellows base, one or more folds from the end of the bellows body are crushed and polymerized in the axial direction. By making the thickness of this terminal overlapping part greater than the plate thickness of the bellows body,
The outer periphery of this terminal overlapping part and the outer periphery of the bellows body are welded together over the entire circumference, and furthermore, at the connection part between the bellows cap and the bellows body, one or more folds are welded from the end of the bellows body. By collapsing and polymerizing in the axial direction, the thickness of this end overlapping part is made to be at least twice the plate thickness of the bellows body, and the outer peripheral edge of this end overlapping part and the outer periphery of the bellows cap are welded together over the entire circumference. An accumulator featuring: (2) The accumulator according to claim 1, wherein the outer diameter of the bellows cap is slightly larger than the outer diameter of the terminal overlapping portion of the bellows body. (3) Manufacture a bellows that includes a metal bellows body with pleats formed by plastic working and whose edges face toward the center of the bellows, and a metal bellows base welded to one open end of the bellows body. In this case, by crushing the ends of the bellows body in the axial direction by one or more folds and polymerizing, the thickness of the end overlapped portion is made larger than the plate thickness of the bellows body, and the end A method for manufacturing an accumulator, characterized in that a bellows base is fixed to a bellows body by welding the outer peripheral edge of the bellows base and the outer peripheral part of the bellows base to each other over the entire circumference. (4) Manufacture a bellows that includes a metal bellows body with pleats formed by plastic working and whose edges face toward the center of the bellows, and a metal bellows cap welded to one open end of the bellows body. In this case, by crushing the ends of the bellows body in the axial direction by one or more folds and polymerizing, the thickness of the end overlapped portion is made larger than the plate thickness of the bellows body, and the end A method for manufacturing an accumulator, characterized in that a bellows cap is fixed to a bellows body by welding the outer circumference of the bellows cap and the outer circumference of the bellows cap to each other over the entire circumference.