JPS6231723A - Boot for machine shaft coupling - Google Patents

Abstract

PURPOSE:To make it possible to raise the abrasion resistance of a bellows part, by forming a straight part which connects the bellows part and a diametrically thick part to each other, as the thickness of this straight part is decreased. CONSTITUTION:A bellows a part 14 is connected to a diametrically thick part 13 by a cylindrical straight part 15. Supposing that the thickness of the straight part 15 is A, and the thickness of a part of the bellows part 14, which leads to the straight part 15, is B, respective thicknesses of the straight part 15 and the part of the bellows part 14 are formed in the condition meeting 0.6<A/B<1.1. Accordingly, the thickness of the straight part is decreased in the preset range, and consequently, the abrasion resistance of the bellows part can be raised.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention has a bellows portion between a large diameter portion and a small diameter portion, and the bellows portion and the large diameter portion are connected by a straight portion. This invention relates to improvements to the straight part of boots for mechanical shaft couplings.

<Prior art> Conventionally, in boots for mechanical shaft couplings (hereinafter referred to as "boots") that are attached to constant velocity joints of automobiles, there are some boots that have a bellows part between a large diameter part and a small diameter part ( 1)
In order to prevent the large diameter side part of the bellows part from getting caught in the joint and (2) to improve the swinging properties of the bellows part, as shown in Fig. 3, the bellows part 4 and the large diameter There was a structure in which the part 2 was connected by a cylindrical straight part 5 (Utility Model Application No. 58-142455, Utility Model Application No. 58-17)
(See Publication No. 8562). In addition, 3 is a small diameter part, 6 is a joint outer ring, 7 is a rotating shaft, 8 is a fastening member, and 9 is a roller.

In the above type of boot l, in order to maintain the effects of (1) and (2) above by giving rigidity to the straight part 5, the thickness of the straight part 5 is made thicker than that of the bellows part 4. ((1,45 to 2.5 times).

<Problems to be Solved by the Invention> However, in the boot l as described above, due to the rigidity of the straight part 5, the bellows part 4 that occurs when the joint crosses
The contact pressure increases at the contact portion (C in Figure 3) I. In other words, it becomes difficult for the peaks and valleys of the bellows part 4 to escape to the larger diameter side at the contact part, so wear is accelerated in the contact part, and as a result, the boot 1 shown in FIG. This includes the problem of reduced wear resistance.

In other words, conventionally, after comparing the disadvantage of reduced wear resistance of the bellows part 4 of the boot 1 with the advantage of preventing the bellows part from getting caught in the joint and swinging around,
In order to improve the overall durability of the boots, the straight portion 5 is made thick.

Therefore, an object of the present invention is to further improve the durability of the boot by improving the abrasion resistance of the bellows part.

Means for Solving Problems〉 As a result of repeated testing and research in an attempt to achieve the above object, the inventors of the present invention have found that even if the wall thickness of the straight part is thinned within a predetermined range compared to the conventional example, it is possible to It was discovered that there is no practical problem in preventing the bellows part from getting caught and swinging around, and the bellows part is placed between the large diameter part and the small diameter part, and the bellows part and the large diameter part are connected by a straight part. The boots are dirty, and the thickness A of the straight part and the thickness B of the bellows part of the part connected to the straight part are 0.6<A/B<1
<Embodiment> of completed boot formed to meet the requirements of ゜1 Hereinafter, the configuration of the boot according to the present invention will be specifically explained based on the drawings.

FIG. 1 is a half-sectional view of a boot 11 according to the present invention, and FIG. 2 is a partially enlarged view of the vicinity of the straight portion 15. genuine boots 1
Similar to the conventional example (FIG. 3), the bellows part 1 has a double ridge type bellows part 14 between the large diameter part 13 and the small diameter part 12, and this bellows part 14 has the large diameter part 13 and a cylindrical straight part This is a configuration in which 15 parts are connected. As shown in FIG. 2, if the thickness of the straight portion 15 is A, and the thickness of the bellows portion 14 in the portion continuous to the straight portion 15 is B, the thickness of both is 0.
6 <A/B < 1.1. Here, if the value of A/B is ≧1.1, it will be the same as the conventional example, whereas if the value of A/H is ≦0.6, the straight part 15 will be too thin and will not be straight. The rigidity of the portion 15 decreases, and the bellows portion 14 due to the joint
In addition, the length of the straight portion 15 (as shown in Fig. 2) is 5 to 1 O for constant-velocity joint boots for automobiles. ■■Take and form. If it is shorter than this, the bellows part 14 (particularly the first valley 14a) will be bitten by the joint, or the bellows part will swing around too much. On the other hand, if it is 10 mm or more, the joint will cross, sometimes causing bending, etc., and the membrane length will increase. There is a risk that the length may become shorter, which is undesirable.

The boot 11 configured as described above has the large diameter portion 13 attached to the joint outer ring 16 and the small diameter portion 12 attached to the rotating shaft 17 to prevent grease leakage inside the boot and intrusion of dust, water, etc. from the outside. Large diameter portion 1 with a fastening member 18 such as a clamp
3. Tighten each small diameter portion 12. Note that 19 is a roller.

Further, as the molding material for the boots 11, NR, NB
Examples include rubbers such as R, SBR, BR, and CR, and TPEs such as urethane-based, vinyl-based, polyester-based, and polyolefin-based. The boots 11 are formed by injection molding in the case of rubber, and injection blow molding in the case of TPE.

<Effects of the Invention> As described above, in a boot that has a bellows part between a large diameter part and a small diameter part, and the bellows part and the large diameter part are connected by a straight part, the flesh of the straight part As is clear from the test results described later (see Figure 4), the thinner boots of the present invention have a lower thickness than Snake IIs! The wear resistance of i'i11 is greatly improved.

During the above test, no problems such as the bellows part getting caught in the joint occurred. Further, regarding the swinging performance of the boot, as shown in FIG. 5, the thinning of the straight portion did not have any adverse effects.

From the above results, the present invention improves the abrasion resistance of the bellows part while maintaining the results of the straight part (preventing the bellows part from being bitten by the joint and improving the swingability of the boot). Therefore, the present invention significantly improves the durability of the boot.

Test Results> Hereinafter, the results of each durability test of the boots (manufactured by CR) shown in Fig. 1 are shown.

□Figure 4□ Figure 4 is a graph showing the relationship between the ratio of the wall thickness A of the straight part to the wall thickness B of the bellows part in the part connected to the straight part, and the durability time (the black circles in the figure are the results of the conventional test. results).

Durability time was determined by wear and tear on the bellows part.

Crossing angle of joint - 1-15 degrees Test temperature -------10 degrees Celsius Rotation speed ---
-----------350rp ■Fill the inside of the boot with grease for the joint.

Here, if the thickness A of the straight part is made thinner than the thickness B (2.4 mm) of the part continuous to the straight part, the durability of the boot (abrasion resistance of the bellows part) will be A/ As the ratio of B becomes smaller than the value of about 1.1, it begins to increase, and at the maximum it becomes about five times that of the conventional example.

□Figure 5□ Figure 5 is a graph showing the relationship between the wall thickness A of the straight portion of the boot, the straightness, and the limit rotation speed for whirling. (The black circles in the figure indicate the test results of the conventional example.) The limit rotational speed for whirling was determined as the rotational speed at which deformation due to the centrifugal force of the enclosed grease due to whirling suddenly increased.

Crossing angle of joint --- 15 degrees Test temperature --- 1-1 0° C. Fill the inside of the boot with joint grease.

Incidentally, the wall thickness B of the bellows portion was set to 2.4 cm as described above.

Here, it was found that even if the wall thickness of the straight part was changed, the turning limit rotation speed remained approximately constant, and that making the straight part thinner had no effect on the swinging performance of the boot.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 show one embodiment of the boot of the present invention.
The figure is a half-sectional view showing the state in which the boot 11 is attached to the joint, FIG. 2 is an enlarged sectional view of the vicinity of the straight part 15, and FIG. 3 is a cross-sectional view showing the state in which the conventional boot l is attached to the joint. It is a diagram. Figure 4 is a graph showing the relationship between the ratio of the wall thickness A of the straight part to the wall thickness B of the bellows part of the part connected to the straight part and the durability time, and Figure 5 is a graph showing the relationship between the wall thickness of the straight part and the swing resistance limit. It is a graph showing the relationship with the rotation speed. 11... Boot (for mechanical shaft coupling), 12... Small diameter part, 13... Large diameter part, 14... Bellows part, 15... Straight part, A... Thickness of straight part , B...Snake in the part that connects to the straight part)! [Thickness of part. 4th Q 5th 0.80,9 1,0 1,1 1,2 13 +4
(A) Day

Claims (1)

[Scope of Claim] A boot for a mechanical shaft coupling, which has a bellows part between a large diameter part and a small diameter part, and the bellows part and the large diameter part are connected by a straight part, wherein the straight part The wall thickness A of the portion and the wall thickness B of the bellows portion of the portion continuous with the straight portion are formed to satisfy the following inequality 0.6<A/B<1.1. Boots for mechanical shaft couplings.