JPH0687776U - Resin CVJ boots - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the durability of the boot by reducing the contact pressure between the peaks on the compression side of the bellows portion near the large diameter mounting portion. [Structure] Mountain group A in the bellows portion 3 near the small-diameter mounting portion 5
Sanya the diameter difference C ₁ smaller form than the peaks and valleys diameter difference C ₂ mountain group B of the large径装attaching portion 4 near the small diameter mounting portion 5 in the compression side of the boot 1 when the operating angle is deformed given The development length of the peaks A _{1 to} A ₃ closer to each other is reduced to reduce the function of promoting the compression of the peaks B _{4 to} B ₆ closer to the large-diameter mounting portion 4, thereby reducing the contact pressure between the peaks. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 INDUSTRIAL APPLICABILITY The present invention is mounted on two shafts that rotate at an operating angle (crossing angle) θ like a constant velocity joint by a large diameter mounting portion and a small diameter mounting portion at both ends of the bellows portion, and is used for grease retention and dust prevention. The present invention relates to resin boots (in this specification, such boots are collectively referred to as CVJ boots). More specifically, the present invention relates to an improvement in the ridge-valley shape of the bellows portion of the resin CVJ boot.

[0002]

[Prior art]

 Generally, as shown in FIG. 5, the CVJ boot 22 has a large-diameter mounting portion 24 that is mounted on the outer ring portion 26 of the constant velocity joint 21 and a small-diameter mounting portion 25 that is mounted on the rotating shaft portion 27. It is provided at both ends of the portion 23. This CVJ boot has two to four ridges in the case of rubber, which has been the mainstream in the past, but it is as flexible as rubber in the case of resin, which is being developed recently. Since there are no crests, the number of crests is set to be larger than that of rubber to facilitate deformation. For example, as a conventional resin-made CVJ boot, a hexagonal, substantially conical shape as shown in FIG. 5 is known.

[0003]

[Problems to be solved by the device]

 However, in the case of resin CVJ boots, which requires a larger number of peaks than rubber, when the constant velocity joint has a large working angle, There is a problem in that the contact pressure between the peaks becomes large, especially in the peaks near the large-diameter mounting portion 24, causing damage due to wear or the like and reducing durability. In particular, if you want to make the boot the same size as the rubber CVJ boot, or if you want to make the boot compact in order to reduce the amount of grease to be filled and to prevent interference with the members around the boot, the mountains close to the large-diameter mounting part There is a problem that the contact pressure is extremely high and the durability is poor.

An object of the present invention is to provide a resin CVJ boot in which the contact pressure between the mountains on the compression side of the bellows portion near the large diameter mounting portion is reduced and the durability is improved.

[0005]

[Means for Solving the Problems]

 As a result of various studies conducted by the present inventors in order to achieve such an object, all the peaks are uniformly compressed in the axial direction in the deformation of the boot on the compression side when a large operating angle is applied to the constant velocity joint. It seemed that it would occur as if drawing a single curve, but in reality, we came to discover that it transforms to draw an S-shape. This is because the center P of the working angle of the constant velocity joint and the mounting center O of the large-diameter mounting portion of the boot are deviated as shown in FIG. 4, so that not all the ridges on the compression side are compressed. Rather, it seems that it partially spreads in the axial direction. Also, on the extension side (the one where the biaxial crossing angle is wide), not all the peaks are stretched (deployed) in the axial direction, but are partially compressed. The expanding mountain movement tends to promote the movement of the mountain that is about to be compressed, and causes the mountains to come into strong contact with each other, and in particular, the contact pressure at the mountain portion tends to become stronger. It has been found that such a phenomenon, that is, a phenomenon of spreading on the compression side without being compressed occurs at a mountain portion near the small diameter mounting portion.

The present invention has been made based on the above findings, and includes a bellows portion, a large-diameter mounting portion provided at one end of the bellows portion, and a small-diameter mounting portion provided at the other end of the bellows portion. In the resin boot provided with, the difference in the valley diameter of the group of valleys near the small-diameter mounting portion in the bellows portion is made smaller than the difference in the valley-valley of the group of valleys near the large-diameter mounting portion.

[0007]

[Action]

 Therefore, even if the operating angle of the constant velocity joint is increased, the development length of the ridges and valleys near the small diameter mounting part with a small ridge / valley difference on the compression side is small, and the corresponding amount of ridges and valleys near the large diameter mounting part is small. They do not help each other to be compressed and reduce the contact pressure in that part.

[0008]

[Embodiment] Hereinafter, the configuration of the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 shows an embodiment of the resin CVJ boot of the present invention. This resin CVJ boot is mounted on a constant velocity joint 2 of an automobile, and includes a bellows portion 3 and a large-diameter mounting portion 4 fitted to an outer ring portion 6 of the constant velocity joint 2 at one end of the bellows portion 3. And a small-diameter mounting portion 5 fitted to the rotary shaft portion 8 of the constant velocity joint 2 at the other end of the bellows portion 3. The large-diameter mounting portion 4 and the small-diameter mounting portion 5 are fastened and fixed to the constant velocity joint 2 side by the fixtures 7 and 9, respectively.

Since this CVJ boot is made of resin, it is provided so as to be easily deformed by increasing the number of peaks as compared with the case of rubber. Usually, in the case of boots used for constant velocity joints for automobiles, at least 4 to 7 mountains are formed, and in some cases, 7 or more mountains are formed. Incidentally, a thermoplastic resin is generally used as the resin forming the boot.

The bellows portion 3 is roughly divided into two mountain groups, a mountain group B near the large-diameter mounting portion 4 and a mountain group A near the small-diameter mounting portion 5. As for the valley-valley difference C ₁ , C ₂ of each mountain belonging to these two mountain groups A and B, a large difference is set between the mountain group A and the mountain group B, and the mountains belonging to the same mountain group are The size is also different to some extent. Then, the largest of the valley-valley difference C ₁ of the mountain group A near the small-diameter mounting portion 5 is formed smaller than the smallest of the mountain-valley diameter difference C ₂ of the mountain group B on the large-diameter mounting portion 4 side. Has been done. Here, the ridge-valley diameter difference means the difference from the apex of the ridge portion 10 forming one ridge to the bottom point of the valley portion 11 on the inner peripheral surface side, that is, the height of the ridge. Of course, it is also possible to set all the mountains belonging to the same mountain group to the same difference in valley diameter.

For example, when the number of peaks of the bellows portion 3 is 6, the first mountain A ₁ , the second mountain A ₂ , and the third mountain A ₃ are included in the mountain group A of the small-diameter mounting portion 5. The fourth mountain B ₄ , the fifth mountain B ₅ , and the sixth mountain B ₆ belong to the mountain group B of the large-diameter mounting portion 4. In this example, a valley portion (a valley portion between the third mountain A ₃ and the fourth mountain B ₄ ) D that divides the number of peaks into two equal parts is used as a boundary between the large and small peaks C ₁ and C ₂ . . However, it is not necessary to make the number of mountain groups A and B equal to each other, and in some cases, it is possible to make a difference in the valley-valley difference at a position deviated from the midpoint of the bellows part 3, that is, the mountain groups A and B. It is possible to have different numbers of mountains.

Here, each mountain valley of the mountain group A is provided so as to be located between the mountains of the mountain group B. That is, between the inner diameter position of the valley portion (indicated by the line i) and the outer diameter position of the mountain portion (indicated by the line o) in the case of the mountains forming the mountain group B assumed at the position of the mountain group A. It is provided so that the mountains and valleys of the mountain group B can be accommodated.

The arrangement relationship of the mountains of the mountain group A and the mountain group B is not particularly limited to that shown in FIG. 1. For example, as shown in FIG. 2, the mountain group B near the large diameter mounting portion 4 and the small diameter group B are arranged. Both mountain groups A and B may be formed so that the inner peripheral surfaces of all the valleys of the mountain group A 1 closer to the mounting part 5 are in contact with one smooth curved (bullet-shaped) inner tangent line 12.

According to the resin CVJ boot configured as described above, when the operating angle is applied to the constant velocity joint, it is deformed as follows. The description will be given for the boot of the embodiment shown in FIG. Further, in FIG. 3, the upper side portion of the rotary shaft portion 8 in the bellows portion 3 is the extension side, and the lower side portion is the compression side.

For example, when the CVJ boot is bent due to the operating angle of the constant velocity joint as shown in FIG. 3, on the compression side, the mountains B _{4 to} B belonging to the mountain group B near the large diameter mounting portion 4 are located. ₆ is compressed in the axial direction, and the mountains A _{1 to} A ₃ belonging to the mountain group A near the small-diameter mounting portion 5 are unfolded. At this time, since the peak-to-valley diameter difference C ₁ of the peaks A _{1 to} A ₃ belonging to the peak group A near the small-diameter mounting portion 5 is formed small, the development length (the length by which the peaks expand and extend in the axial direction) is short, mountain B ₃ .about.B ₆ belonging to the mountain group B of the large径装attaching portion 4 closer is not able to assist in Ru compressed.

On the other hand, even on the extension side, the mountains B _{4 to} B ₆ belonging to the mountain group B near the large diameter mounting portion ₄ are widened, and the mountains A _{1 to} A ₃ belonging to the mountain group A near the small diameter mounting portion 5 are reversed. Is compressed to. However, by shrinking the mountain group A with a small difference between the mountain valleys near the small-diameter mounting part 5, the expansion of the mountain group B that spreads is absorbed to some extent, and the entire boot boots with one small radius of curvature. To prevent Thus, boot the inner peripheral surface for whole not bend less by without any and entire one radius of curvature mountain B ₃ .about.B ₆ large径装attaching portion 4 closer to what is deformed S-shape is brought into strong contact with each other is There is no contact with the rotating shaft 8 of the constant velocity joint 2.

It should be noted that the above-described embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, the present invention is not particularly limited to the boot structure shown in FIGS. 1 and 2, and as shown in FIG. 4, the inner tangent line 13 of the mountain group A near the small-diameter mounting portion 4 and the mountain near the large-diameter mounting portion 5 are shown. It is also possible to form the inner tangent line 14 of the group B in a stepwise discontinuous manner and to make the mountain heights of the mountain group A and the mountain group B largely different. In this case, it is possible to increase the difference in peak-valley diameter difference C ₁ , C ₂ between the mountain group B from the large-diameter mounting portion 5 and the mountain group A closer to the small-diameter mounting portion 4.

[0019]

[Effect of device]

 As is clear from the above explanation, in the present invention, the difference in the valley diameter of the valleys near the small diameter mounting portion in the bellows portion is smaller than that in the valleys near the large diameter mounting portion. When the working angle of the constant velocity joint is large, the development length of the mountain group on the small diameter mounting part side on the compression side is reduced, and the contact pressure between the mountains on the large diameter mounting part side is reduced accordingly. The durability of the boots can be improved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a resin CVJ boot of the present invention together with a constant velocity joint.

FIG. 2 is a vertical cross-sectional view showing another embodiment of the resin CVJ boot of the present invention together with a constant velocity joint.

FIG. 3 is an explanatory view showing a deformed state of the boot of FIG. 2 when the constant velocity joint has an operating angle.

FIG. 4 is a vertical sectional view of still another embodiment of the resin CVJ boot of the present invention.

FIG. 5 is a vertical cross-sectional view of a conventional resin CVJ boot.

[Explanation of symbols]

1 Boots 2 Constant velocity joint 3 Bellows part 4 Large-diameter mounting part 5 Small-diameter mounting part A Mountain group near the small-diameter mounting part B Mountain group near large-diameter mounting part A _{1 to} A ₃ Mountains on the small-diameter mounting part side B _{4 to} B ₆ Large-diameter mounting side

Claims (1)

[Scope of utility model registration request] 1. A resin CVJ boot having a bellows portion, a large-diameter mounting portion provided at one end of the bellows portion, and a small-diameter mounting portion provided at the other end of the bellows portion. A resin CVJ boot, characterized in that the difference in the valley diameter of the group of valleys near the small-diameter mounting portion is formed smaller than the difference in the valley diameter of the group of valleys near the large-diameter mounting portion.