JPH0631217Y2 - Seal washer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a seal washer.

[Prior Art] In a device such as a compressor in which a pressure fluid is sealed, when the constituent elements are coupled with a bolt, the bolt hole is hermetically sealed so that the pressure fluid inside the device does not leak to the outside. , A seal washer is interposed between the bolt head and the component. The seal washer is generally pressed from a brass plate into a predetermined shape and size.

[Problems to be solved by the invention] However, during the rolling process of the brass plate, fine cracks are unavoidably generated in the surface layer portion thereof. This crack remains after it is molded into a predetermined seal washer, and when used for joining components that require airtightness, the pressure fluid inside the device leaks out through the crack.

The present invention compensates for the inevitable residual cracks to prevent pressure fluid from leaking through the cracks when the seal washer is interposed between the bolt and the component, and to seal the seal washer. It is a technical issue to be solved to improve the property.

[Means for Solving the Problems] In order to solve the above problems, the present invention uses a seal washer with Hv.
The seal washer is made of a copper-based metal having a hardness of 50 to 70, and the surface layer of the seal washer is plated with tin having a thickness of 2 μm or more.

The shape of the seal washer is not particularly limited, but may be annular as in the conventional case.

Copper and brass can be used as the copper-based metal. Since general copper and brass have a hardness of Hv90 to 110, the hardness of copper and brass is adjusted to Hv50 to 70 by annealing after forming a washer in the present invention. This is to maintain the minimum shape for functioning as a seal washer when the washer is tightened between the bolt and the component, and to increase the amount of plastic deformation due to the tightening force of the bolt head.

The tin plating is applied to the entire surface layer of the washer by general electroplating. The thickness of the tin plating is set to 2 μm or more. When the thickness is less than 2 μm, cracks generated on the washer surface are filled with a particularly soft tin film. This is because doing so becomes insufficient. The hardness of this tin plating is approximately Hv1
5 to 20.

[Operation] As described above, the present invention forms a washer with a copper-based metal softened by an annealing treatment, and a soft tin plating is applied to the surface layer thereof. Therefore,
Even if a crack is unavoidably generated on the washer surface of the present invention, the washer undergoes a large plastic deformation due to the tightening pressure of the bolt, and the tin film, which is softer than the washer, further assists in filling the crack. The pressure is reduced or erased to the extent that it does not allow the fluid to flow.

[Example] Hereinafter, an example in which the seal washer of the present invention is applied to a compressor will be described as an example.

First, the structure of the compressor will be briefly described with reference to FIGS. 4 and 5. Note that FIG. 4 is a front view of the compressor, and FIG.
The figure is an irregular sectional view in which the tightening bolt portion is locally cut away.

As shown in the drawing, a cylinder 31 having an elliptical through hole is housed and fixed in the front housing 11 and the rear housing 21 which are coupled to each other, and the openings at both ends of the cylinder 31 are closed by a front side plate 41 and a rear side plate 51, respectively. The interior space is formed by peeling off. A drive shaft 71 is rotatably held in the shaft holes of the both side plates 41 and 51 via bearings 42 and 52, and one end of the drive shaft 71 penetrates the shaft hole of the front housing 11 via a shaft seal 15. And then project,
A driven portion of an electromagnetic clutch (not shown) is fixed to the tip 72. Further, the drive shaft 71 has a rotor 6 having a circular cross section.
1 is fixed so as to be arranged in the internal space, and four vanes 91 that can project and retract in the radial direction are supported by the rotor 61. The suction chamber 12 is formed between the front side plate 41 and the front housing 11, and the discharge chamber 22 is formed between the rear side plate 51 and the rear housing 21. The suction chamber 12 receives the supply of the refrigerant gas through the introduction hole 13, while the discharge chamber 22 sends out the compressed refrigerant through the discharge hole 23.

The sub-assembly including the cylinder 31, the front side plate 41 and the like is fastened to the front housing 11 with bolts 81. The bolt 81 is tightened in a screw hole formed in the cylinder 31 through a bolt hole 14 formed in the front housing 11 and a through hole formed in the front plate 41. Then, the bolt 81 and the front housing 11
Between this and the seal washer 1 according to the present invention is a bolt hole 1
It is interposed so as to seal 4.

A plan view of the seal washer 1 is shown in FIG. Also,
FIG. 2 (a) is a sectional view taken along the line AA of FIG. This seal washer 1 is made by processing a general brass plate into a washer shape by an ordinary press working, adjusting the hardness to Hv 50 to 70 by annealing, and further electroplating the surface layer thereof to a tin plating thickness of 2 μm. Is applied. Most of the seal washers 1 have fine cracks 1a remaining on their surfaces.

In order to confirm the sealing property of the seal washer 1, the seal washer 1 and a general brass seal washer (hardness Hv90 to 110) for comparison are applied to the compressor as described above, and the bolt 81 Tightening torque is 12
The leakage of the pressure fluid from the bolt holes 14 was observed by setting 0 kgf · cm and 170 kgf · cm. It should be noted that residual cracks were also found on the surface of the brass seal washer used for comparison in the above experiment.

According to the experimental results, the seal washer 1 according to the present example did not cause any leakage failure even when the tightening torque was as small as 120 kgf · cm. This is because the seal washer 1 according to the present embodiment has a hardness as low as Hv 50 to 70, and the surface layer portion thereof is tin-plated 2. Therefore, the cross section of the seal washer 1 after being tightened with the bolt 81 is the second As shown in FIG. (B), the tightening pressure of the bolt 81 causes the upper portion of the seal washer 1 to undergo a large plastic deformation, and the softer tin film on the surface layer portion further assists in the filling of cracks, thus substantially It is considered that the cracks were reduced or eliminated to the extent that pressure fluid could not be conducted. On the other hand, with the seal washer according to the comparative example, the tightening torque is 12
When 0 kgf · cm, 80% of the leakage failure occurred, and when the tightening torque was 170 kgf · cm, the leakage failure of 60% occurred. This is because the hardness of the seal washer according to the comparative example is as high as Hv90 to 110, so that the amount of plastic deformation of the upper portion of the seal washer due to the tightening pressure of the bolt 81 is the same as that of the present embodiment, as shown in FIG. It is considered that it is smaller than that of No. 1 and the cracks remain without being sufficiently filled.

In addition, in the present embodiment, the example of the countermeasure against the crack remaining on the surface of the seal washer 1, that is, the side in contact with the bolt 81 is shown. However, the crack remaining on the back surface of the seal washer 1 in contact with the front housing 11 is Is usually formed of a soft metal such as an aluminum alloy, so that the plastic deformation of both the soft tin plating 2 and the aluminum alloy compensates the cracks to a substantially harmless degree.

[Effect of the Invention] As described in detail above, the seal washer of the present invention is Hv5.
Since a copper-based metal adjusted to a low hardness of 0 to 70 is used, and the surface layer portion is tin-plated with a film thickness of 2 μm or more, unavoidably remaining cracks are inevitably formed in the pressure fluid. It can be reduced or erased to the extent that conduction is not allowed. Therefore, when the seal washer of the present invention is applied to the connecting portion of the components that require sealing, leakage of the pressure fluid can be completely and reliably prevented.

[Brief description of drawings]

FIG. 1 is a plan view of a seal washer according to this embodiment, and FIG.
FIG. 1A is a sectional view taken along the line AA of FIG. 1, and FIG. 2B.
Is a cross-sectional view of the seal washer of the present embodiment after tightening with bolts, FIG. 3 (a) is a cross-sectional view of the seal washer according to the comparative example, and FIG. 3 (b) is of the comparative example after tightening with the bolt. FIG. 4 is a cross-sectional view of the seal washer, FIG. 4 is a front view of a compressor to which the seal washer of this embodiment is applied, and FIG. 5 is an irregular cross-sectional view in which the fastening bolt portion is locally cut away. 1 ... Seal washer, 1a ... Crack 2 ... Tin plating 11 ... Front housing 12 ... Suction chamber, 14 ... Bolt hole 21 ... Rear housing, 81 ... Bolt

Claims (1)

[Scope of utility model registration request] 1. A seal washer made of a copper-based metal having a hardness of Hv50 to 70 and hermetically sealing a bolt hole having a surface layer portion plated with tin having a film thickness of 2 μm or more.