JPH085377Y2 - Boots for constant velocity joints - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a boot for a constant velocity joint.

[Conventional technology]

As boots to protect constant velocity joints from dust,
Blow-molded boots made of a polyester-based resin (for example, a product name “HYTREL”) having excellent durability are used. An example of such a boot is shown in FIGS. 4 and 5.

The boot 31 shown in FIG. 5 and FIG. 6 has a large diameter end 33 provided at one end of a bellows-shaped body 32 and a small diameter end provided at the other end.
34 is provided. Large diameter end 33 is a constant velocity joint 35
The outer ring 36 is fitted into a mounting portion 37 on the outer diameter surface of the outer ring 36, and is fixed by a special caulking type band 38. The small-diameter end portion 34 is fitted to the mounting portion 40 of the shaft 39 and fixed by the caulking type band 41 similar to the above. These mounting parts 37, 40
Each of them is provided with a plurality of ridges 42 and 43 so that the tightening force is concentrated on the ridges 42 and 43.
A step portion 44 is formed on the mounting portion 37 of the outer ring 36, the large diameter end portion 33 is pressed against the step portion 44 to prevent axial movement, and is formed on the inner diameter surface of the tip of the small diameter end portion 34. Ridge 45
By fitting (see FIG. 5) into the groove of the mounting portion 40, the boot 31 is axially positioned.

The boot 31 has a large-diameter end portion after the shaft 39 is assembled to the inner race 46 by inserting the small-diameter end portion 34 from the end portion of the shaft 39 on the serration 47 side before the shaft 39 is assembled to the inner race 46. 33 and the small diameter end 34 are fixed to the outer ring 36 and the respective mounting portions 37 and 40 of the shaft 39 by tightening bands 38 and 41, respectively.

[Problems to be solved by the device]

While the material of the boot 31 described above is very hard, the tensile fatigue strength is low, so that it is necessary to reduce the occurrence of tensile stress in the portion of the pleats 48 when the body 32 is bent, and therefore, the body 32 has a shaft. It is installed by compressing in the direction. But,
Attaching the body portion 32 in a compressed state is a cause of impairing workability. For the same reason, it is necessary to increase the outer diameter of the body portion 32 and increase the length of the pleats 48.
It is disadvantageous in terms of installation space and cost of the boot 31.

In addition, because the material is hard, the large diameter end 33 and the small diameter end 34 need to use special caulking type bands 38 and 41, and if the bands 38 and 41 are not tightly tightened, they easily loosen. If the looseness progresses, the boot 31 may come off.

Further, the inner diameter of the small-diameter end portion 34 is formed to have a size larger than the diameter of the serration 47, but the diameter of the mounting portion 40 has a small diameter so as not to create a gap between the small-diameter end portion 34 and the mounting portion 40. It must be dimensioned to match the inside diameter of the end 34. Therefore, the diameter of the material of the shaft 39 is
It must be selected larger than the diameter of 40 (larger than the diameter of the serration 47), and there is a disadvantage that the turning allowance of the shaft 39 increases due to the larger diameter of the material.

Further, at the small diameter end portion 34, a ridge 45 is provided on the inner diameter surface for positioning. However, a special technique is required to form the ridges 45 with high precision at the same time when the boot 31 is blow-molded.

Therefore, the technical problem of the present invention is to solve the above-mentioned problems.

[Means for solving the problem]

In order to solve the above problems, the first means of the present invention is to provide a boot for a constant velocity joint in which a large diameter end portion and a small diameter end portion are provided at both ends of a bellows-shaped body portion. Is composed of a trunk main body including a large-diameter end and a trunk auxiliary body including a small-diameter end, and the trunk main body is formed of a hard synthetic resin and the trunk auxiliary body is formed of a flexible material. The body and the body are integrated by a connecting portion that is in sliding contact with the outer diameter surface of the shaft.

[Action]

In the boot having the above-described structure, the trunk main body bends and expands and contracts as the constant velocity joint bends and expands and contracts, and the trunk auxiliary body expands and contracts following the expansion and contraction of the trunk main body.

[Embodiment] The boot 1 according to the first embodiment shown in FIG. 1 includes a body 2 made of polyester synthetic resin such as "Hytrel" and a CR body.
(Chloroprene) rubber body auxiliary body 3. The trunk main body 2 has a plurality of pleats 4 and also has a large-diameter end portion 8 that is fitted to the mounting portion 7 of the outer ring 6 of the constant velocity joint 5. Two ridges 9 are formed on the mounting portion 7, and the conventional step portion is formed.
There is no equivalent to 44 (see Figure 5). The reason why the step portion 44 is unnecessary will be described later. As the tightening band 10, a tightening type similar to the conventional one is used.

A connecting portion 11 for connecting the auxiliary body 3 is formed at the other end of the main body 2. A small gap is provided between the connecting portion 11 and the outer diameter surface of the shaft 12 of the constant velocity joint 5, and the gap allows the connecting portion 11 to slide in the axial direction while being positioned in the radial direction. it can.

An engaging groove 13 is formed on the outer diameter surface of the connecting portion 11, and a connecting portion 14 formed at one end of the body auxiliary body 3 is integrally engaged with the engaging groove 13 with a proper interference. The trunk main body 2 and the trunk auxiliary body 3 are connected.

The body auxiliary body 3 also has a plurality of pleats 15, and is fitted in the mounting groove 18 in the circumferential direction of the shaft 12 at the small-diameter end portion 16 of the boot 1 with an appropriate interference, and is positioned in the axial direction. In this case no tightening band is required.

In order to further ensure the integration of the connecting portions 11 and 14, the groove formed on the outer diameter surface of the connecting portion 14 as shown in FIG.
Fit the tightening band 21 on the 20 and tighten it. However, the gap between the inner diameter surface of the connecting portion 11 and the shaft 12 is maintained.
Further, as shown in FIG. 3, the projection 22 provided on the connecting portion 11 of the trunk main body 2 is fitted into the hole 23 of the connecting portion 14 of the trunk auxiliary body 3 to ensure the integration of the two. Good.

In the boot 1 having the above-described configuration, when the constant velocity joint 5 operates and bends and expands, the folds 4 of the main body 2 are deformed, and the connecting portions 11 and 14 slide in the axial direction, so that the auxiliary body 3 The folds 15 follow and expand and contract.

In the conventional case, when the constant velocity joint 5 is bent,
In order to relieve the tensile stress generated in the pleats 4 of the trunk main body 2, the pleats 4 of the main body 2 were attached in a state of being compressed in the axial direction. In the case of this invention, the tensile stress acting on the pleats 4 is
It is absorbed by the sliding movement of the connecting portions 11 and 14 and the body assisting body 3 which expands and contracts following the sliding movement. Therefore, it is not necessary to axially compress the pleats 4, and therefore the mounting portion 7 such as the conventional step portion 44 is unnecessary.

Further, the diameter of the shaft 12 portion into which the connecting portion 11 is fitted may be the same as the diameter of the serration portion 24, and need not be thicker than that.

The body auxiliary body 3 may be made of any material other than CR rubber, as long as it can be expanded and contracted in the axial direction and can seal with the shaft 1.

[Effect of device]

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

(1) It is not necessary to use a crimping type special tightening band that has been conventionally used on the small-diameter end portion side, and it is possible to reduce cost and improve workability.

(2) The diameter of the shaft material can be made smaller than that of the conventional one, so that the turning allowance can be reduced.

(3) Conventionally, a ridge for positioning was formed on the inner diameter of the small-diameter end of the boot by a special method. However, such a ridge is not necessary and the accuracy of the inner diameter surface of the connecting portion is rough. The boots can be easily molded since any material can be used.

(4) Since it is not necessary to mount the main body in a compressed state, the assembling work is easy, and it is not necessary to provide a step on the mounting portion of the outer ring.

(5) Since the small diameter portion of the body is slidable with respect to the shaft, the tensile stress or compressive stress acting on the body is reduced, and the life of the boot is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view in a use state of the first embodiment, FIGS. 2 and 3 are vertical sectional front views showing a part of a modified example of the same, and FIG. 4 is a vertical sectional front view of a conventional example. The drawing is a partially enlarged sectional view of FIG. 1 ... boots, 2 ... body mainly, 3 ... body assisting body, 4 ...
Folds, 5 ... Constant velocity joint, 6 ... Outer ring, 7 ... Mounting part, 8 ... Large diameter end, 9 ... Projection, 10 ... Tightening band,
11 …… Coupling part, 12 …… Shaft, 13 …… Engagement groove, 14 ……
Connection part, 15 pleats, 16 ...... small diameter end part, 18 ...... mounting groove,
20 …… groove, 21 …… tightening band, 22 …… projection, 23 …… hole,
24 …… Serration.

Claims (1)

[Scope of utility model registration request] 1. A boot for a constant velocity joint, comprising a large-diameter end portion and a small-diameter end portion at both ends of a bellows-shaped body portion, wherein the bellows-shaped body portion includes a main body and a small-diameter end portion including the large-diameter end portion. And a body auxiliary body including a portion, the main body of the body is made of a hard synthetic resin, the body auxiliary body is made of a flexible material, and the body main body and the body auxiliary body are slidably in contact with the outer diameter surface of the shaft. Boots for constant velocity joints characterized by being integrated by.