JPH0571545U - Boot fixing structure - Google Patents

Abstract

(57) [Summary] [Purpose] Excellent in airtightness and durability, and also ensures the positioning of the fixed part and the shaft part. [Constitution] The boot comprises a bellows portion 2 having tubular fixing portions 3 and 4 formed at both ends. The fixing portions 3 and 4 are fitted and inserted into a shaft portion 5 and an outer ring 7 of a device such as a joint housed in the boot 1, and fastened and fixed by bands 6A and 6B, respectively. The fixing portion 3 fixed to the shaft portion 5 is formed with an outward projecting portion projecting outward on the outer surface of the portion close to the bellows portion. An inward protrusion 3C is formed on the inner surface of a portion of the fixed portion 3 facing the outward protrusion 3A formed on the outer surface of the portion closer to the bellows portion.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fixing structure between a boot and a shaft portion of a device such as a joint housed inside the boot.

[0002]

[Prior Art]

 Conventionally, a boot seal structure described below has been proposed as this type of fixing structure.

As shown in FIG. 6, a plurality of annular ridges 111 and an annular recess 112 adjacent to each annular ridge 111 are provided on the outer peripheral surface of the shaft 110 of the universal joint 108. First, the annular convex portion 105 protruding from the inner peripheral surface of the end portion of the small diameter portion 103 provided at one end of the bellows portion 102 of the boot 101 is engaged, and the small diameter portion 103 of the small diameter portion 103 is connected by the ring-shaped stopper metal fitting 107. The part of the kerf 106 formed on the outer surface is tightened (see Japanese Utility Model Laid-Open No. 61-91668).

[0004]

[Problems to be solved by the device]

 In the above-mentioned conventional technique, as shown in detail in FIG. 6, the inner peripheral surface of the small diameter portion 103 is a simple cylindrical surface whose inner diameter does not change in the axial direction. There is a problem that the work of fitting and holding the outer peripheral surface at a predetermined position is troublesome.

Further, a cut groove is provided in the small diameter portion to prevent the stopper from being displaced, but this portion needs to have a wall thickness of 1.2 mm or more in order to obtain a sealing property. As a result, the wall thickness of the small diameter portion becomes thicker by that amount, the flexibility of the small diameter portion becomes worse than that of the bellows portion, and there is a problem that the durability of the boundary portion between the two decreases.

The present invention has been made in view of the problems of the above-mentioned conventional techniques, and is excellent in airtightness and durability, and moreover, the positioning between the fixing portion and the shaft portion can be surely performed. The purpose is to realize a fixing structure of boots.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the fixing structure of a boot of the present invention is a fixing structure of a boot composed of a bellows portion having tubular fixing portions at both ends thereof and a shaft portion of a device housed therein. The shaft portion of the device has a plurality of annular projections formed at intervals in the axial direction of the outer surface of the device, while the fixing portion fixed to the shaft portion of the fixing portion is An outer projecting portion that projects outward is formed on the outer surface of the portion closer to the bellows portion, and an inner projecting portion is formed on the inner surface of the portion facing the outer projecting portion that is formed closer to the bellows portion. It is characterized in that an inward protrusion projecting inward is formed.

[0008]

[Action]

 As described above, the fixing portion fixed to the shaft portion has the inward projection formed on the inner surface thereof near the bellows portion, so that the fixing portion and the shaft portion can be reliably positioned. In addition, the inner surface of the shaft is always in contact with the outer surface of the shaft, so that the airtightness of both is improved.

[0009] In addition, since the outer protrusion of the fixing portion that is closer to the bellows portion is formed with the outward projecting portion, the outer projecting portion of the fixing portion is formed correspondingly. It is possible to ensure flexibility by setting the thickness of the portion other than the portion to be smaller than that of the conventional example.

[0010]

【Example】

 An embodiment of the present invention will be described with reference to the drawings.

1 to 4 show a first embodiment of the present invention, FIG. 1 is a partially cutaway plan view thereof, FIG. 2 is an enlarged sectional view showing a part of a fixing portion thereof, and FIG. FIG. 4 is an explanatory view showing the part shown in FIG. 2 in a disassembled state, and FIG.

As shown in FIG. 1, the boot 1 is made of a flexible material such as rubber or plastics, and includes a bellows portion 2 having tubular fixing portions 3 and 4 formed at both ends. .. The boot 1 can be molded by a known molding method, and particularly in the case of plastic, injection molding, blow molding or injection blow molding can be used.

The fixing portions 3 and 4 are fitted and inserted into a shaft portion 5 and an outer ring 7 of a device such as a joint housed in the boot 1, and fastened and fixed by bands 6A and 6B, respectively.

As shown in FIGS. 2 and 3, the fixing portion 3 fixed to the shaft portion 5 has five annular projections 5A formed on the outer surface of the shaft portion 5 at intervals in the axial direction. In order to prevent the band 6A from shifting in the axial direction, it has enough length to cover all of it, and the outer projections 3A and 3B projecting outward are respectively provided on the outer surfaces of the portion close to the bellows and the opening side. It is formed in a ring.

Further, on the inner surface of the portion facing the outer protruding portion 3A formed on the outer surface of the portion close to the bellows portion, an inward protruding portion 3C protruding inward is formed in an annular shape, and the fixing is performed. The part 3 and the shaft part 5 are positioned.

Further, as shown in FIG. 4, in this embodiment, the four outer protrusions 3 A are formed at substantially equal intervals along the outer peripheral surface of the fixing portion 3. On the other hand, the inward projection 3C is formed as a single ring on the inner peripheral surface. Therefore, it is possible to secure the flexibility by setting the thickness of the portion of the fixing portion 3 other than the portion where the outward projecting portions 3A and 3B are formed to be relatively thin.

FIG. 5 shows a second embodiment and is a sectional view of the same portion as FIG. In the present embodiment, contrary to the first embodiment, the outer protruding portion 13A formed near the bellows portion is formed in an annular shape on the outer peripheral surface of the fixing portion 13, and is formed at a portion facing this. Four inner protrusions 13C are formed along the inner peripheral surface of the small-diameter fixed portion 13 at substantially equal intervals.

In the first embodiment, a plurality of outer protrusions 3A are formed, and in the second embodiment, a plurality of inner protrusions 13C are formed along the peripheral surface. By virtue of this, particularly when molding by blow molding, it is possible to improve the resin surroundings, so that it is possible to completely form the outer protrusion 3A or the inner protrusion 13C.

By the way, as shown in FIG. 3, the height A of the outer protrusion 3 A, the height B of the inner protrusion 3 C, and the tip portion of the fixing portion 3 formed in the portion of the fixing portion 3 closer to the bellows portion 2. When the height C of the outer protruding portion, the height D of each annular protruding portion 5A, the height E of the fixed portion near the bellows portion, and the pitch F of each annular protruding portion 5A are set to the values described below, Good.

A: 1.85 mm (suitable range 0.8 to 2.2 mm) B: 0.3 mm (suitable range 0.1 to 0.5 mm) C: 1.2 mm (suitable range 1.0 to 2.5 mm) ) D: 0.2 mm (suitable range 0.1 to 0.5 mm) E: 1.35 mm (suitable range A> E, 0 to 2.0 mm) F: 3.0 mm (suitable range 2.4 to 3.5 mm) )

[0021]

[Effect of the device]

 Since the present invention is configured as described above, it has the following effects.

Since the inward projecting portion that projects inward is formed at the portion of the inner surface of the fixing portion that is fixed to the shaft portion near the bellows portion, the axial positioning of the fixing portion and the shaft portion is ensured. At the same time, since the inner surface of the shaft portion is always in contact with the outer surface of the shaft portion, airtightness is improved.

[0023] In addition, since the outward protrusion protruding outward is formed on the outer surface of the portion of the fixing portion near the bellows portion, the portion of the fixing portion other than the portion on which the outward protrusion is formed is formed. It is possible to secure the flexibility by setting the wall thickness of the resin to be relatively thin and to improve the durability of the fixed portion near the bellows portion.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view showing a first embodiment of a boot fixing structure of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a part of a fixing portion fixed to a shaft portion of the first embodiment.

FIG. 3 is an explanatory diagram showing a state in which a portion shown in FIG. 2 is disassembled.

FIG. 4 is a sectional view taken along the line AA of FIG.

FIG. 5 is a sectional view of a portion similar to FIG. 4 showing a second embodiment.

FIG. 6 shows a conventional example, (A) is a sectional view thereof, and (B) is an enlarged sectional view of a main part thereof.

[Explanation of symbols]

 1 boot 2 bellows part 3,4 fixed part 3A, 3B outer protruding part 3C inner protruding part 5 shaft part 5A annular protruding part 6A, 6B band 7 outer ring

Claims (1)

[Scope of utility model registration request] 1. A structure for fixing a boot consisting of a bellows portion having tubular fixing portions formed at both ends and a shaft portion of a device housed therein, wherein the shaft portion of the device has an outer surface shaft thereof. A plurality of annular protrusions formed at intervals in the direction are provided. On the other hand, the fixing portion fixed to the shaft portion of the fixing portion is outwardly provided on the outer surface of the portion close to the bellows portion. An outward projecting portion is formed, and an inward projecting portion projecting inward is formed on the inner surface of the portion facing the outer projecting portion formed in the portion close to the bellows portion. The fixed structure of the boot that is characterized by being.