JPH07101056B2 - How to install boots for constant velocity universal joints - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for attaching a boot for a constant velocity universal joint used in an automobile or the like, and particularly to a method for attaching a highly durable synthetic resin boot.

[Prior art]

Generally, a boot for a constant velocity universal joint is attached to prevent the enclosed lubricating grease from flowing out and at the same time prevent dust and the like from entering from the outside. In the boot for constant velocity universal joint, the mounting portion provided on the large diameter side end portion is externally fitted and fixed to the outer ring of the constant velocity universal joint, and the mounting portion provided on the small diameter side end portion is externally fitted and fixed to the rotating shaft. Then, the constant velocity universal joint is hermetically covered to hold the lubricating grease enclosed therein. When an automobile is running under severe conditions, a boot made of a hard and highly elastic thermoplastic synthetic resin is used to prevent the durability of the boot from being deteriorated even when a small stone or the like comes in from the outside or is contacted with a piece of wood or the like. It came to be used. However, since the above-mentioned thermoplastic synthetic resin boot is highly elastic at room temperature, the inner diameter dimension of the mounting portion of the large-diameter side end portion and the small-diameter side end portion of the boot is slightly increased to facilitate fitting. Then, the boots were fixed with the boot tightening band.

Problems to be Solved by the Invention When the inner diameter is increased, a gap is created between the outer ring and the rotary shaft, which causes a problem that a stronger tightening band is required. The present invention has been made to solve the above problems, and provides a method for mounting boots for constant velocity universal joints that facilitates boot mounting work and does not require a strong tightening band. Is the purpose.

[Means for solving problems]

In order to solve the above problems, the present invention is a method of attaching a boot made of thermoplastic synthetic resin to an outer ring and a rotary shaft of a constant velocity universal joint, wherein the boot has a large-diameter side end and a small-diameter side end. The mounting part of the part is swollen with an organic solvent, and after the external fitting, the organic solvent is removed by heating.

【Example】

An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the outer ring 1 has a shaft portion 2 at a closed end, and a plurality of curved ball grooves 4 are provided on a spherical inner peripheral surface 3. The inner ring 5 has a spherical outer peripheral surface 6 and is provided with a number of curved ball grooves 7 corresponding to the number of the ball grooves 4 of the outer ring 1. In the ball grooves 7 and 4 of the inner and outer rings 5 and 1, the spherical outer inner peripheral surface 6 of the inner and outer rings 5 and 1,
A cage 9 for guiding the torque transmitting balls 8 is arranged. The inner ring 5 is spline-fitted to the end of the rotary shaft 10. Boots that cover the constant velocity universal joint as described above
11, a large-diameter side mounting portion 12 is externally fitted to the outer ring 1 and further tightened and fixed by a band 13, and a small-diameter side mounting portion 14 is externally fitted and fixed to a rotating shaft 10 by a band 15. The boot mounting portions 12 and 14 are attached to the outer ring 1 and the rotary shaft, respectively.
When fitting to 10, the mounting parts 12 and 14 are previously immersed in an organic solvent such as trichloroethylene for a certain period of time, and the mounting part 1 is
The inner diameters of the mounting portions 12 and 14 are slightly expanded by the swelling action, and the outer portions of the mounting portions 12 and 14 are externally fitted. After that, in order to return the mounting portions 12 and 14 to the initial inner diameter dimensions, the mounting portions 12 and 14 were allowed to stand in a constant temperature bath for a certain period of time in a fitted state, and then immersed in the mounting portions 12 and 14. Remove the organic solvent. In this way, the mounting portions 12, 14 and the outer ring 1 and the rotary shaft 10 are fitted tightly together without a gap. At this time, a temporary band may be used so that the mounting positions of the mounting portions 12, 14 and the outer ring 1 and the rotary shaft 10 do not shift. Next, another mounting method will be described. Swollen mounting part
After the outer ring 1 and the rotary shaft 10 are externally fitted to the outer ring 1 and the rotary shaft 10, respectively, the shaft portion 2 and the rotary shaft 10 are supported so that the outer ring 1 and the rotary shaft 10 have the same axis center. Then, as shown in FIGS. 2 and 3, the circular arc-shaped porous bodies 16, 16 ', 17, made of a sintered alloy,
17 'is put on the outer periphery of the mounting portions 12 and 14. This porous body 1
Since 6, 16 ', 17, 17' are preheated by a heater or the like, the organic solvent impregnated in the mounting parts 12, 14 absorbs the conduction heat from the porous bodies 16, 16 ', 17, 17'. Receive and evaporate. In particular, the organic solvent evaporated at the contact portion between the porous bodies 16, 16 ', 17, 17' and the mounting portions 12, 14 is the porous body 1
It is discharged to the outside through the fine holes 6, 16 ', 17, 17'. As a result, the mounting portions 12, 14 and the outer ring 1, the rotary shaft 10
Are closely fitted without any gap. Here, the porous bodies 16, 16 ', 17 and 17' are the mounting portions 12,
It suffices that it has a hole through which the solvent molecules used for swelling 14 can be easily released, and it is not particularly limited to a sintered alloy. The thermoplastic synthetic resin that is the material of the boot 11 is a polyester-based or polyurea-based elastic body, and the organic solvent is a solvent that swells the thermoplastic synthetic resin such as trichlorethylene or acetone. However, as the organic solvent for swelling the boot 11, one having a boiling point of 90 ° C. or less is used, and the inside of the thermostat and the porous bodies 16, 16 ′, 17,
Even when 17 ′ is heated to around 90 ° C., it does not affect the physical properties of the grease and the boot 11 because the lubricating grease and the boot 11 have a heat resistant temperature or lower. The thermoplastic elastic body targeted here is a polyester system,
Or, with a polyurea elastic body, this kind of rubber elastic mechanism is set so that the hard segment in the molecule is responsible for the ordinary rubber cross-linking part and the soft segment is responsible for elongation, and it is a primary bond like a general vulcanized rubber. There is no bridging part. Therefore, by swelling with the organic solvent, the mobility of molecules is increased, and plastic deformation occurs with a small force. Furthermore, since the initial physical properties are restored after the solvent is evaporated, the desired physical deformation can be achieved without impairing the initial physical properties by the swelling treatment. Further, depending on the type of the solvent, the compounding agent in the thermoplastic synthetic resin may be transferred during the above treatment, which may lead to deterioration of the physical properties after the treatment. Add to the solvent to reduce the concentration gradient,
It is good to prevent that transition.

[Effect]

As described above, the present invention swells the large-diameter side end portion and the small-diameter side end portion of the boot with an organic solvent such as trichlorethylene, and fits the boot onto the outer ring and the rotary shaft to mount the boot. By heating the part to remove the organic solvent,
Since the boot is closely fitted to the outer ring and the rotary shaft, the work for attaching the boot becomes easy. Further, in the boot attached by the method of the present invention, the tightening band can be eliminated depending on the usage conditions of the constant velocity universal joint.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a boot used in the method according to the present invention. FIG. 2 is an explanatory view of another method for removing the organic solvent impregnated in the mounting portion. FIG. 3 is a schematic view of a cross section of a main part of FIG. 1 …… Outer ring 5 …… Inner ring 10 …… Rotating shaft 12,14 …… Mounting part 13,15 …… Band 16,16 ′, 17,17 ′ …… Porous body

Claims (1)

[Claims] 1. A method for mounting a boot made of a thermoplastic synthetic resin to an outer ring and a rotary shaft of a constant velocity universal joint, wherein the mounting portions at the large diameter side end portion and the small diameter side end portion of the boot are made of an organic solvent. A method for mounting a boot for a constant velocity universal joint, which comprises swelling, fitting after heating, and heating to remove the organic solvent.