JPH0228296Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a floating seal used mainly as an external seal around the suspension of a civil engineering construction machine, such as a caterpillar.

[Conventional technology]

Conventionally, this type of floating seal
The one shown in FIG. 4 is widely used.
In the figure, reference numerals 11 and 16 are a pair of floating rings that are loosely fitted around the outer periphery of a non-rotating fixed shaft 2 that protrudes from the body (not shown), and the cross-sectional shape is approximately L.
One of the floating rings 11 has an elastic ring 5 made of rubber material on the inner periphery of the stepped portion 4 of the non-rotating housing 3 fixed to the body side.
The other floating ring 16 is supported by an elastic ring 9 made of a rubber material on the inner periphery of the stepped portion 8 of the rotating housing 7, which is rotatably inserted onto the outer periphery of the fixed shaft 2 via a bearing (not shown). is carried through. The elastic rings 5 and 9 maintain airtightness between the housing 3 and the floating ring 11 on the non-rotating side and between the housing 7 and the floating ring 16 on the rotating side, and also maintain airtightness between the inner circumferences of both stepped portions 4 and 8. Surfaces 4', 8' and outer peripheral surfaces 11b, 16 of both floating rings 11, 16
b are inclined in opposite directions so as to form a figure-eight shape, so that the components of the elastic force of the elastic rings 5 and 9 that press against these act in both the axial and radial directions. In other words, the floating rings 11 and 16 are caused to slide closely against each other with an appropriate load on their opposing sliding surfaces 11a and 16a, and displacement in the radial direction is restricted.

[Problem that the invention attempts to solve]

In the above conventional configuration, both the housings 3,
Since the inner circumferential surfaces 4', 6' of the stepped portions of the floating rings 11, 16 and the outer circumferential surfaces 11b, 16b of the floating rings 11, 16 are inclined in a simple taper shape, the elastic rings 5, 9 are compressed in the direction (axial direction). When the housings 3, 7 and the floating rings 11, 16 are displaced relative to each other in the radial direction), the amount of compressive deformation of the elastic rings 5, 9 increases in proportion to the amount of displacement, and the elastic rings The load due to Nos. 5 and 9 increases rapidly when the amount of compressive deformation exceeds a certain limit. Generally, the elastic rings 5, 9 are
Housing 3, 7 and floating ring 1
1, 16, relatively large crushing allowances 5', 5', 9',
9' is removed, that is, it is inserted in a compressed state by that amount. Therefore, due to installation errors of the floating seals and variations in device accuracy, excessive compressive deformation occurs in the elastic rings 5, 9 due to relative displacement between the housings 3, 7 and the floating rings 11, 16. When it happens,
Due to the sudden increase in the load on the elastic rings 5 and 9,
Stable sealing performance and durability of both floating rings 11 and 16 could no longer be obtained.

In view of this problem, the present invention has a structure that can suppress compressive deformation of the elastic ring due to relative displacement between the housing and the floating ring.
This is what we are trying to solve.

[Means for solving problems]

As a means for achieving this object, the floating seal of the present invention has the stepped inner circumferential surfaces of both housings that are in pressure contact with the elastic rings and the outer circumferential surfaces of both floating rings inclined to each other so as to form a figure-eight shape, and At least one of the inner circumferential surface and the outer circumferential surface is curved or bent over the entire circumference in a shape that bulges out most toward the elastic ring at the center of the inclined portion, and is different between the small diameter side and the large diameter side of the surface. The structure has an inclined angle.

[Effect]

In the present invention, when the curved or bent portion is formed on the inner circumferential surface of the stepped portion of the housing, the inclination angle of the inner circumferential surface becomes gentler on the small diameter side,
Further, when the floating ring is formed on the outer circumferential surface of the floating ring, the inclination angle of the outer circumferential surface becomes gentler on the larger diameter side. Therefore, even if the relative displacement between the housing and the floating ring increases, the crushing allowance of the elastic ring escapes from the center of the most swollen slope, and the amount of compression does not increase rapidly, so the load (stress due to compression) The increase in is alleviated.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings. In each embodiment, parts that overlap with the conventional structure shown in FIG. 4 are given the same reference numerals.
The explanation will be omitted.

First of all, FIG. 1 shows a first embodiment, in which the inclined parts 1a and 6a of both floating rings 1 and 6, which face each other and slide closely, bulge outward over the entire circumference. The amount of bulge is the slope portions 1a, 6
Forming the largest curved surfaces 1b and 6b at the center a,
In other words, the angle of inclination on the outer circumferential surface of the inclined portions 1a, 6a becomes gradually gentler from the small diameter portions 1b-1, 6b-1 toward the large diameter portions 1b-2, 6b-2. Therefore, as shown in a partially enlarged view in FIG. 2, for example, the floating ring 1 and the housing 3 are relatively aligned with
When the elastic ring 5 is displaced in the A' direction, the elastic ring 5 is compressed accordingly, and the elastic ring 5 moves along the curved surface 1b of the floating ring 1 at the large diameter portion 1b-2 with a gentle inclination angle. Since it seems to escape relatively to the side, the rate of increase in the amount of compression is moderated, and a sudden increase in load (stress due to compression) can be prevented.

Further, FIG. 3 shows another embodiment of the present invention, in which the inclined portions 1 of both floating rings 1 and 6 are shown.
Bent surfaces 1c and 6c are formed at the centers of a and 6a, respectively, so as to bulge outward over the entire circumference, that is, the small diameter side 1c-
1, 6c-1 has a large inclination angle, large diameter side 1c-2,
6c-2 has a shape in which the inclination angle is small, and has substantially the same effect as the first embodiment.

In each of the above-mentioned embodiments, the curved portion or bent portion is formed on the inclined portion of the floating ring. The object of the present invention can be achieved even if the angle of inclination is made gentler on the small diameter side.

[Effect of idea]

As explained above, the floating seal of the present invention can maintain the compression margin of the elastic ring even if there is relative displacement between the housing and the floating ring in the direction of compressing the elastic ring, or there are installation errors or variations in equipment accuracy. Due to the "relief", the amount of compression is maintained within an appropriate range, thereby preventing an abnormal increase in the load on the floating ring and achieving stable sealing performance and durability.

[Brief explanation of the drawing]

Fig. 1 is a half-cut side sectional view showing one embodiment of the floating seal of the present invention, Fig. 2 is an enlarged sectional view of the same main part, and Fig. 3 is a half-cut side sectional view showing another embodiment of the present invention. FIG. 4 is a half-cut side sectional view showing a conventional structure. 1, 6...Floating ring, 1a, 6a
... Slanted part, 1b, 6b ... Curved surface, 1c, 6c
...Bent surface, 3,7...Housing, 4,8...
Stepped portion, 5, 9... elastic ring.

Claims (1)

[Scope of utility model registration request] A pair of opposing floating rings are loosely fitted onto the outer periphery of the shaft and supported airtightly and elastically on the stepped inner peripheries of the non-rotating side housing and the rotating side housing through elastic rings, respectively, and slide closely against each other. In a floating seal that prevents foreign matter such as muddy water from entering from the outside, the stepped inner circumferential surfaces of the two housings and the outer circumferential surfaces of the two floating rings are inclined to each other so as to form a figure-eight shape, and At least one of the circumferential surface and the outer circumferential surface is curved or bent over the entire circumference in a shape that bulges out most toward the elastic ring at the center of the inclined part, and has different inclination angles on the small diameter side and the large diameter side of the surface. A floating seal characterized by: