JP2005180526A - Boot for constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boot for a constant velocity universal joint, not generating repeated stress on a bellows part side corner part of a band applied part. <P>SOLUTION: This boot for a constant velocity universal joint includes: an annular bellows part P2 formed to be elastically deformed; a one end side annular connecting part P1 with a comparatively small diameter, which is provided on one end side of the annular bellows part and connected to the shoulder part S of the annular bellows part, and the other end side annular connecting part P3 with a comparatively large diameter, which is provided on the other end side of the annular bellow part. The one end side annular connecting part is provided with the band applied part 4 where a one end side connecting band 2 is applied, and the annular bellows part side of the base 4a of the band applied part is provided with a band positioning projecting part 12 projected outward over the base. When the distance between the base of the band applied part and the axis X of the boot for the constant velocity universal joint is R1, and the distance from the axis to a point W of intersection of the annular bellows part side wall surface 12a of the projecting part and the surface connected to the shoulder part of the annular bellows part is R2, the relationship expressed by R1≥R2 is satisfied. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a constant velocity joint boot for protecting, for example, a constant velocity universal joint used in a drive shaft (drive shaft) and a propulsion shaft (propeller shaft) of an automobile.

  Conventionally, for example, constant velocity joints used in automobile drive shafts (propeller shafts) and propulsion shafts (propeller shafts) are sealed with grease as a lubricant, and in order to prevent entry of dust and water from the outside. Various constant velocity joint boots (for example, inboard side (engine side) constant velocity joint boots, outboard side (tire side) constant velocity joint boots) are mounted.

  For example, as shown in FIGS. 3A and 3B, one end side annular fastening portion P1 that can be fastened to the shaft portion 100 of the constant velocity joint is provided on one end side of the constant velocity joint boot. The other end side is provided with the other end side annular fastening portion P3 that can be fastened to the gear housing (outer sleeve) 102 of the constant velocity joint. The one end side annular fastening portion P1 and the other end side are provided. Between the annular fastening portion P3, an annular bellows portion P2 is provided that can be elastically deformed following a relative angular change between the shaft portion 100 of the constant velocity joint and the gear housing 102.

  The one end side annular fastening portion P1 and the other end side annular fastening portion P3 are provided with band attaching portions 106 and 108 for attaching the one end side fastening band 104 and the other end side fastening band (not shown), respectively. The one end side fastening band 104 and the other end side fastening band are respectively attached to these band attaching portions 106 and 108 and tightened, whereby the one end side annular fastening portion P1 can be fastened to the shaft portion 100 of the constant velocity joint. The other end side annular fastening portion P3 can be fastened to the gear housing 102 of the constant velocity joint. In particular, the band mounting portion 106 of the one-end-side annular fastening portion P1 is formed by notching (falling) the outer peripheral surface of the one-end-side annular fastening portion P1 along the circumferential direction into a concave section. When the band 104 is mounted on the band mounting portion 106, the one end side fastening band 104 is positioned between the end side wall surface 106a and the bellows side wall surface 106b of the band mounting portion 106.

  By the way, the constant velocity joint rotates at various operating angles while the vehicle is running, and accordingly, the constant velocity joint boot has a shape change such as bending or expansion / contraction (FIGS. 3C to 3F). As a result, repeated stress (for example, tensile stress, compressive stress, bending stress, shear stress, torsional stress, etc.) is generated. In particular, in the band mounting portion 106 having a concave cross section of the one-end-side annular fastening portion P1, stress is repeatedly concentrated on the bellows portion side corner portion (intersection portion of the bottom surface 106c and the bellows portion side wall surface 106b) G. .

More specifically, the constant-velocity joint boot is in a state where stress is not generated (initial state in which bending or expansion / contraction is not performed: FIG. 3C) (FIG. 3D) or contracted. In the process of changing shape to the state (FIG. (E)) and the most contracted state (FIG. (F)), the bellows side corners (the bottom surface 106c and the bellows side wall surface 106b) of the band mounting portion 106 are intersected. Part) With the G as a fulcrum, the rocking deformation of the annular bellows part P2 (shoulder part 110) is repeated. As a result, repeated stress is concentrated on the bellows portion side corner portion G of the band mounting portion 106.
The occurrence of such stress concentration is caused by cutting the outer peripheral surface of the one-end-side annular fastening portion P1 continuous from the shoulder 110 of the annular bellows portion P2 into a concave cross section (decreasing), thereby forming a constant velocity joint boot. The reason is that the internal force generated in the annular bellows portion P2 (shoulder portion 110) during the elastic deformation acts on the bellows side corner G of the band mounting portion 106 where the angle changes sharply.

  When such stress concentration is repeated over a long period of time, cracks may occur in the stress concentrated portion (the bellows portion side corner G of the band mounting portion 106). If this happens, grease will scatter from the cracked part and the lubricity of the constant velocity joint will deteriorate, or foreign particles such as dust and water may enter from outside and damage the constant velocity joint. There is a possibility that rotation cannot be transmitted to the shaft) or propeller shaft (propeller shaft) at a constant speed.

Therefore, for example, in the constant velocity joint boot shown in Patent Document 1, as shown in FIG. 4, the bellows portion side corner G of the band mounting portion 106 of the one-end-side annular fastening portion P <b> 1 is formed into a curved surface. The stress concentration is suppressed by dispersing the stress generated in.
However, when the bellows portion side corner G of the band mounting portion 106 is a curved surface, if the degree of bending is increased, the suppression effect against repeated stress increases accordingly, but the one end side fastening band 104 (FIG. 3). (a)) rides on the curved surface (the curved surface enters under the one end side fastening band 104), and the one end side fastening band 104 and the bottom surface 106c of the band mounting portion 106 and the curved surface (corner portion side corner). Part G) is tightened at the same time. In this case, it becomes difficult to fasten the one-end-side annular fastening portion P1 to the shaft portion 100 (FIG. 3A) of the constant velocity joint with a uniform tightening force. If the sealing performance between the fastening portion P1 is insufficient, the grease sealed in the constant velocity joint boot may leak out between the shaft portion 100 and the one-end-side annular fastening portion P1. There is.
JP 2001-3950 A

  In the prior art described above, the main focus is on suppressing the stress generated at the bellows side corner of the band mounting portion, whereas the present invention is repeated at the bellows side corner of the band mounting portion. An object of the present invention is to provide a constant velocity joint boot that does not generate stress.

In order to achieve such an object, the constant velocity joint boot of the present invention is provided with an annular bellows portion formed to be elastically deformable, one end side of the annular bellows portion, and continuous with a shoulder portion of the annular bellows portion. A relatively small-diameter one-end-side annular fastening portion, and a relatively large-diameter other-end-side annular fastening portion provided on the other end side of the annular bellows portion. A band mounting portion to which the fastening band is mounted is provided, and a band positioning convex portion protruding outward from the bottom surface is provided on the annular bellows portion side of the bottom surface of the band mounting portion. .
In such a configuration, the distance between the bottom surface of the band mounting portion and the axial center of the constant velocity joint boot is R1, and the side surface of the annular bellows portion of the convex portion and the surface continuous to the shoulder portion of the annular bellows portion intersect. When the distance from the axis of the intersection is R2, the relationship R1 ≧ R2 is satisfied.
In this case, the convex portions may be provided continuously in the circumferential direction along the band mounting portion of the one-end-side annular fastening portion, or may be provided at predetermined intervals in the circumferential direction along the band-mounting portion of the one-end-side annular fastening portion. May be provided intermittently. Further, a curved surface may be formed with a predetermined curvature at the bellows portion side corner of the band mounting portion where the bottom surface of the band mounting portion intersects the convex portion.

  Provided on the annular bellows portion side of the bottom surface of the band mounting portion is a band positioning convex portion protruding outward from the bottom surface, and between the bottom surface of the band mounting portion and the axis of the constant velocity joint boot. By satisfying R1 ≧ R2 in the relationship of the distance R1 and the distance R2 from the axial center of the intersection point where the side surface of the annular bellows portion of the convex portion and the surface continuous to the shoulder portion of the annular bellows portion meet, All the compressive stress, tensile stress, etc. generated in the shoulder due to elastic deformation act on the cross section closer to the axis than the bellows side corner of the band mounting portion. In this case, since stress is not repeatedly generated at the bellows portion side corner of the band mounting portion, it is impossible that the portion is cracked and damaged. Therefore, the durability of the constant velocity joint boot can be further improved.

Hereinafter, a constant velocity joint boot according to an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIGS. 1 (a) and 1 (b), the constant velocity joint boot according to the present embodiment is provided with an annular bellows portion P2 formed to be elastically deformable, and one end side of the annular bellows portion P2. A relatively small-diameter one-side annular fastening portion P1 continuous to the shoulder S of the annular bellows portion P2 and a relatively large-diameter other-end-side annular fastening portion P3 provided on the other end side of the annular bellows portion P2. I have.

In the annular bellows portion P2, a plurality of annular ridge portions M and annular valley portions V are alternately combined from the annular shoulder portion S continuous with the one end side annular fastening portion P1 toward the other end side annular fastening portion P3. It is shaped like a hollow cone. With such a configuration, the annular bellows part P2 is maintained in a state where it can be elastically deformed elastically.
The one end side annular fastening portion P1 is provided with a band attaching portion 4 to which the one end side fastening band 2 is attached. By attaching the one end side fastening band 2 to the band attaching portion 4 and tightening, one end side is provided. The annular fastening portion P1 can be fastened to the shaft portion 6 of the constant velocity joint.
The other end side annular fastening portion P3 is provided with a band attaching portion 8 to which an unillustrated other end side fastening band is attached, and the other end side fastening band is attached to the band attaching portion 8 and tightened. The other end side annular fastening portion P3 can be fastened to the gear housing (outer sleeve) 10 of the constant velocity joint.

In the present embodiment, a band positioning convex portion 12 protruding outward from the bottom surface 4a is provided on the annular bellows portion side of the bottom surface 4a of the band mounting portion 4 of the one-end-side annular fastening portion P1. The distance between the bottom surface 4a of the band mounting portion 4 and the axis X of the constant velocity joint boot is R1, and the surface that is continuous with the annular bellows side wall surface 12a of the convex portion 12 and the shoulder portion S of the annular bellows portion P2. When the distance from the axis X of the intersection point W where the crossing points is R2, the relationship R1 ≧ R2 is satisfied.
In FIG. 1 (b), as an example of a constant velocity joint boot satisfying such a relationship, a boot having a smoothly continuous tapered surface from the shoulder portion S of the annular bellows portion P2 to the intersection point W is assumed. .

Further, the bottom surface 4a of the band mounting portion 4 is defined between the band positioning flange 14 provided at the end of the one end side annular fastening portion P1 and the flange 14 side wall surface 12b of the convex portion 12. It forms a straight cylindrical surface (parallel to the axis X) with no undulation or inclination. In this case, when the one end side fastening band 2 is attached to the band attaching portion 4, the one end side fastening band 2 is positioned between the flange portion 14 and the flange portion 14 side wall surface 12 b of the convex portion 12. The band mounting portion 4 includes a bottom surface 4a, a convex portion 12, and a flange portion 14.
In this case, in the relationship between the distance R1 from the axis X of the bottom surface 4a of the band mounting portion 4 and the distance R2 from the axis X of the intersection W (R1 ≧ R2), the tapered cone extends from the shoulder S of the annular bellows portion P2. It is only necessary that the smoothly continuous surface is positioned closer to the axis X than the bottom surface 4a at the intersection point W or on the same plane as the bottom surface 4a. As for the shape of the other parts, it is possible to adopt any shape, and therefore there is no limitation here. In addition, since the boot thickness of the portion from the shoulder portion S of the annular bellows portion P2 to the one-end-side fastening band 2 can be set to an arbitrary thickness according to the use purpose or use environment of the boot, There is no limitation here.

  By satisfying such a positional relationship, all of the compressive stress and tensile stress generated in the shoulder portion S due to the elastic deformation of the annular bellows portion P2 are closer to the axis X than the bellows side corner of the band mounting portion 4. Act on. In this case, the band positioning convex portion 12 is maintained in a state where it is placed on a surface continuous from the shoulder portion S of the annular bellows portion P2 to the one end side annular fastening portion P1, and therefore the annular bellows portion P2 It is not affected at all by the compressive stress or the tensile stress generated in the shoulder portion S due to the elastic deformation. For example, even when the shape change such as bending and expansion / contraction (FIGS. 1C to 1F) is repeated, no stress is repeatedly generated in the bellows side corner G of the band mounting portion 4. In addition, the bellows part side corner part G of the band mounting part 4 refers to the intersection part of the bottom face 4a and the flange part 14 side wall surface 12b of the convex part 12. FIG.

  More specifically, the constant velocity joint boot is in a state in which no stress is generated (initial state in which it is not bent / stretched: FIG. 1C) (FIG. 1D), or in a contracted state. In the process of changing the shape to the state (FIG. (E)) and the most contracted state (FIG. (F)), in the boots of the prior art, the stress is repeatedly concentrated on the bellows side corner G of the band mounting portion 4. However, according to the boot of the present embodiment, the convex portion 12 is projected on the bottom surface 4a, whereby the bellows portion side corner of the band mounting portion 4 is generated. Since the behavior that the annular bellows portion P2 is deformed with the portion G as a fulcrum does not occur at all (obviously also from FIGS. 1C to 1F), it repeats at the bellows portion side corner G of the band mounting portion 4. No stress is generated. In this case, the conventional problem that the bellows portion side corner G is cracked and broken cannot occur. Therefore, the durability of the constant velocity joint boot can be further improved.

In the embodiment described above, the convex portion 12 may be provided continuously in the circumferential direction along the band mounting portion 4 of the one-end-side annular fastening portion P1 (FIG. 2 (a)), or one end It may be provided intermittently at predetermined intervals in the circumferential direction along the band mounting portion 4 of the side annular fastening portion P1 (FIG. 2B).
In this case, in the molding process of the constant velocity joint boot, the convex portion 12 may be formed integrally in the injection process of the one-end-side annular fastening part P1, or may be retrofitted in a process different from the injection process. You may do it. In addition, when providing the convex part 12 intermittently like FIG.2 (b), the number of the convex parts 12 shall be arbitrarily set by the usage purpose and use environment of a boot, or the circumference of the one end side annular fastening part P1. However, there is no limitation here.

  Further, a curved surface may be formed with a predetermined curvature at the bellows portion side corner G of the band mounting portion 4 where the bottom surface 4a of the band mounting portion 4 intersects the convex portion 12 (FIG. 2 (c). )). By making the bellows part side corner G a curved surface, for example, an external force is applied from the one end side fastening band 2 attached to the band attaching part 4 toward the collar part 14 side wall surface 12b of the convex part 12, and the bellows part side Even when the stress is generated in the corner G, the stress can be dispersed on the curved surface, and therefore it is possible to avoid a situation such as a crack or breakage of the bellows side corner G. The size of the curved surface is preferably set to such an extent that the one-end-side fastening band 2 does not ride up (ie, the curved surface does not enter under the one-end-side fastening band 2).

  2 (a) and 2 (b) show an example in which three band positioning collars 14 are provided at the end of the one-end-side annular fastening portion P1. If the fastening band 2 can be positioned with certainty, the number and arrangement of the collar portions 14 can be arbitrarily set, and thus are not limited here.

(a) is the fragmentary sectional view which shows the state where the constant velocity joint boot which relates to the form of execution of this invention is attached to the constant velocity joint, (b) is the enlarged sectional view of the part of the one end side annular fastening part (C)-(f) is a figure which shows a mode that an annular bellows part is elastically deforming. (a) is an enlarged perspective view of a portion of the one-end-side annular fastening portion provided with convex portions continuously in the circumferential direction along the band mounting portion, and (b) is predetermined in the circumferential direction along the band mounting portion. An enlarged perspective view of a portion of the one-end-side annular fastening portion that is intermittently provided at intervals and provided with a convex portion, (c) of the one-end-side annular fastening portion in which a curved surface is formed at the bellows-side corner of the band mounting portion. FIG. (a) is a partial sectional view showing a state in which a conventional constant velocity joint boot is attached to the constant velocity joint, (b) is an enlarged sectional view of a portion of one end side annular fastening portion, and (c) to (f) (A) is a figure which shows a mode that an annular bellows part is elastically deforming. The fragmentary sectional view of the one end side cyclic | annular fastening part by which the curved surface was formed in the bellows part side corner of the band mounting part of FIG.

Explanation of symbols

2 Band 1 for fastening at one end 4 Band mounting portion 4a Bottom face 6 Shaft portion 12 of constant velocity joint Band-shaped convex portion 12a Projected annular bellows side wall surface P1 One end side annular fastening portion P2 Annular bellows portion P3 The other end side annular Fastening portion R1 Distance R2 between the bottom surface of the band mounting portion and the axial center of the constant velocity joint boot R2 Distance from the axial center of the intersection of the side surface of the annular bellows portion and the surface continuous to the shoulder portion S of the annular bellows portion Shoulder W Intersection point X where the side wall surface of the annular bellows part and the surface continuous with the shoulder part intersect The axis of the constant velocity joint boot

Claims (4)

An annular bellows portion formed to be elastically deformable;
A relatively small-diameter one-end-side annular fastening portion provided on one end side of the annular bellows portion and continuing to the shoulder portion of the annular bellows portion;
A constant velocity joint boot comprising a relatively large-diameter other-end-side annular fastening portion provided on the other end side of the annular bellows portion,
The one end side annular fastening portion is provided with a band attaching portion to which a predetermined fastening band is attached, and a band protruding outward from the bottom surface on the annular bellows portion side of the bottom surface of the band attaching portion. Protrusions for positioning are provided,
The distance between the bottom surface of the band mounting portion and the axis of the constant velocity joint boot is R1, from the axis of the intersection where the surface of the convex annular bellows side wall surface and the surface of the annular bellows portion intersect. A constant velocity joint boot characterized by being configured to satisfy the relationship of R1 ≧ R2 when the distance is R2.   The constant velocity joint boot according to claim 1, wherein the convex portion is provided continuously in the circumferential direction along the band mounting portion of the one-end-side annular fastening portion.   The constant velocity joint boot is characterized in that the convex portions are provided intermittently at predetermined intervals in the circumferential direction along the band mounting portion of the one end side annular fastening portion. A boot for a constant velocity joint, wherein a curved surface is formed with a predetermined curvature at a bellows portion side corner of the band mounting portion where a bottom surface of the band mounting portion intersects with a convex portion.

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