JP4173439B2 - Structure for preventing intrusion of water etc. in universal joint boots - Google Patents

Description

  The present invention relates to a structure for preventing water and the like from entering a universal joint boot used in a propeller shaft or the like.

  In a conventional vehicle, a propeller shaft that transmits engine output to a rear wheel is divided in the axial direction, and the divided front and rear shafts are connected by a universal joint. Then, using a boot for preventing the entry of dust, muddy water, etc. into the connection space between the outer and inner of the universal joint, one end of the boot is fitted to the inner and the other end is fitted to the outer and attached. It is going to be.

The boot for a universal joint disclosed in Patent Document 1 avoids abnormal expansion / contraction or breakage of the boot in response to a change in the internal pressure of the boot based on a temperature change due to the heat generated by the universal joint or a change in the internal pressure of the boot based on the slide of the universal joint. A groove-shaped internal pressure adjusting communication passage that communicates the inside and outside of the boot with the fitting portion to the inner is provided.
JP-A-8-28704

  In the universal joint of Patent Document 1, a communication passage that communicates with the inside and outside of the boot is provided at the fitting portion of the boot to the inner portion. Such water easily enters the boot from the communication path. If a large amount of water enters the boot, the joint function will be impaired by rusting of the universal joint.

  An object of the present invention is to prevent intrusion of water or the like from an internal pressure adjusting communication path provided in a fitting portion to a mounted member in a universal joint boot.

  According to the first aspect of the present invention, when one end portion of the boot that seals the connection space of the universal joint is fitted and attached to the attached member, the inside and outside of the boot communicate with the fitting portion of the boot to the attached member. In the structure for preventing intrusion of water or the like of a universal joint boot, in which a passage is provided and a center bearing loaded on the side of the fitting portion of the boot in the mounted member is supported by the annular support member, the boot is attached to the annular support member. A shielding member that covers the fitting portion in the radial direction and the axial direction is provided.

  According to a second aspect of the present invention, in the first aspect of the invention, the small diameter fitting portion at one end of the boot is attached to one attached member, and the large diameter attaching portion at the other end of the boot is attached to the other attached portion. When the small diameter fitting portion of the boot is covered with the shielding member in the radial direction and the axial direction by the shielding member, the shielding member expands to approximately the same diameter as the large diameter fitting portion of the boot, and the large diameter It faces the front surface of the mounting portion.

  According to a third aspect of the invention, in the first or second aspect of the invention, the shielding member is formed integrally with an annular support member.

  The invention of claim 4 is the invention according to any one of claims 1 to 3, wherein the shielding member is made of rubber or synthetic resin.

(Claim 1)
(a) A shielding member provided on the annular support member for supporting the center bearing covers the periphery of the fitting portion of the boot to the attached member in the radial direction and the axial direction to shield it from the outside world. This prevents intrusion of water or the like from the outside into the internal pressure adjusting communication passage.

(Claim 2)
(b) When the shielding member covers the small-diameter fitting portion of the boot in the radial direction and the axial direction, the shielding member expands to approximately the same diameter as the large-diameter mounting portion of the boot, and the large-diameter mounting portion Facing the front. Accordingly, the outside air flowing around the universal joint from the front to the rear is guided outwardly by the outer periphery of the expanding portion of the shielding member so as to be largely separated from the small-diameter fitting portion of the boot, and consequently the large-diameter mounting portion of the boot. It will flow away from the periphery. This prevents water or the like caught in the flow of outside air around the universal joint from entering the small diameter fitting portion of the boot and entering the internal pressure adjusting communication passage.

(Claim 3)
(c) Since the shielding member is integrally formed with the annular support member, it is possible to improve the manageability and assembling property of the shielding member.

(Claim 4)
(d) By forming the shielding member with rubber or synthetic resin, it is possible to improve the rust prevention and lightness of the shielding member.

  FIG. 1 is a cross-sectional view showing a structure for preventing water and the like from entering the universal joint boot, and FIG. 2 is an enlarged view of a main part of FIG.

  FIG. 1 shows a constant velocity universal joint (slidable joint) 20 comprising a first propeller shaft 11 connected to one of the engine side and the drive side, and a second propeller shaft 12 connected to the other of the engine side and the drive side. The connected parts are indicated by. In this embodiment, the first propeller shaft 11 is connected to the drive side, the second propeller shaft 12 is connected to the engine side, the first propeller shaft 11 side is located rearward, and the second propeller shaft 12 side is It will be located forward.

  The universal joint 20 has an outer 21 connected to the first propeller shaft 11 and an inner 23 formed at the tip of a shaft stub 22 connected to the second propeller shaft 12, and the ball 24 is connected to the outer periphery of the inner 23. It is configured by fitting between three grooves 23B and 21A provided at three positions between the surface and the inner peripheral surface of the outer 21.

  The shaft stub 22 of the second propeller shaft 12 is reduced in diameter from the large-diameter portion 22A toward the inner portion 23 at the tip portion in order, such as a medium-diameter portion 22B and a small-diameter portion 22C, and is passed through a center bearing 25 loaded in the small-diameter portion 22C. The annular support member 30 is rotatably supported by the annular support member 30, and the annular support member 30 is provided on the mounting bracket 30A.

  The annular support member 30 is formed by joining an inner ring 31 and an outer ring 32 via a rubber-like elastic member 33. The inner ring 31 has a diameter such as a small diameter part 31A, a medium diameter part 31B, and a large diameter part 31C. The outer ring 25A of the center bearing 25 is fitted inside the medium diameter part 31B, the small diameter part 31A extends to the front covering the outer periphery of the medium diameter part 22B of the shaft stub 22, and has a large diameter. The part 31 </ b> C extends rearward to cover the outer periphery of the small diameter part 22 </ b> C of the shaft stub 22. Further, in the inner ring 31, seal members 34 and 35 are loaded on the inner circumferences of the small diameter portion 31A and the large diameter portion 31C, respectively, and both the seal members 34 and 35 seal the center bearing 25 from both sides. The seal member 35 is in sliding contact with the outer periphery of a stopper piece 40 described later on the rear surface side of the center bearing 25, and the seal member 34 is in sliding contact with the outer periphery of the medium diameter portion 22 </ b> B of the shaft stub 22 on the front surface side of the center bearing 25.

  In the universal joint 20, the center bearing 25 fitted to the inner ring 31 of the annular support member 30 is loaded into the small diameter portion 22 </ b> C of the shaft stub 22, and in this state, the small diameter portion 22 </ b> C of the shaft stub 22 is annular. The stopper piece 40 is press-fitted. The front end portion of the stopper piece 40 penetrates the inside of the seal member 35 and abuts the rear end surface of the center bearing 25. As a result, the front end surface of the inner ring 25B of the center bearing 25 is positioned in contact with the shoulder surface of the medium diameter portion 22B of the shaft stub 22, and the rear end surface of the inner ring 25B is pressed against the front end surface of the stopper piece 40 and positioned. .

  The stopper piece 40 includes a large diameter flange portion 41 and a small diameter flange portion 42. The large-diameter flange portion 41 of the stopper piece 40 is close to the inner periphery of the rear end of the inner ring 31 of the annular support member 30 and prevents water from entering the inner ring 31 that houses the center bearing 25. Further, the water that has entered from the gap between the large diameter flange portion 41 and the inner ring 31 is guided by the annular groove 43 between the large diameter flange portion 41 and the small diameter flange portion 42 and falls downward, and enters the inner ring 31. To prevent the ingress of water.

  Further, in the universal joint 20, as shown in FIG. 2, the connection space 50 between the outer 21 and the inner 23 is sealed using a boot adapter 51 made of a thin metal plate and a boot 60 made of a rubber-like elastic body. -Grease for improving the slidability and durability of the rod 24 is sealed in the connection space 50. The boot 60 prevents entry of dust, muddy water, and the like into the connection space 50.

  The boot adapter 51 includes a base 51A that is inserted around a sealing member 52 such as an O-ring provided on the outer periphery of the outer 21 and is fastened and fixed, and extends in the axial direction of the inner 23 so as to cover the boot 60 from the base 51A. It has a tip 51B.

  The boot 60 is made of a flexible material such as rubber, and has a large cylindrical large-diameter mounting portion 61 that is clamped and fixed to the distal end portion 51B of the boot adapter 51 on the first propeller shaft 11 side. A small cylindrical small-diameter fitting portion 62 is fitted to the outer circumferential fitting portion 23A of the inner 23 on the second propeller shaft 12 side and fixedly attached to the outer circumferential fitting portion 23A by a boot band 65. Further, the boot 60 has a substantially U-shaped cross section between the large-diameter mounting portion 61 and the small-diameter fitting portion 62 and has a bent portion 63 that bends inwardly into the connection space 50.

  The boot 60 has a small-diameter fitting portion 62 extending from the front end of the fitting cylinder portion 62A and a fitting cylinder portion 62A that is connected to the outer circumferential fitting portion 23A in a manner connected to the bending portion 63 to form a free end. And it shall consist of the sealing cylinder part 62B sealed on the outer periphery of the inner 23. FIG. At a plurality of positions in the circumferential direction of the inner circumference of the fitting cylinder portion 62A in the small diameter fitting portion 62, the axial space extending in the axial direction extends through the connection space 50 inside the boot 60 to the inner circumference side of the sealing cylinder portion 62B. A groove-shaped communication passage 64 (the passage 64 may be provided on the outer peripheral fitting portion 23A side) is provided for enabling communication. The sealing cylinder part 62B connected to the fitting cylinder part 62A can be easily expanded / contracted with respect to the outer periphery of the inner 23 in response to a change in the internal pressure of the boot 60, and the diameter is expanded when the internal pressure of the boot 60 is increased. The communication path 64 of 62A is released to the outside, the internal pressure of the boot 60 can be released to the outside, and the diameter of the boot 60 is reduced when the internal pressure of the boot 60 is lowered, so that the communication path 64 of the fitting cylinder portion 62A can be sealed.

  In the boot 60 of the present embodiment, the small-diameter fitting portion 62 includes only the fitting tube portion 62A, and it is not essential to include the sealing tube portion 62B.

  However, in the universal joint 20, as shown in FIG. 2, the small-diameter fitting part 62 (the fitting cylinder part 62 </ b> A and the sealing cylinder part 62 </ b> B) of the boot 60 is radially arranged on the inner ring 31 of the annular support member 30. And the shielding member 70 which covers in an axial direction is provided.

  The shielding member 70 is integrally formed with the inner ring 31 of the annular support member 30 and is configured by an expanding portion 71 that expands from the large diameter portion 31C of the inner ring 31 toward the rear in the axial direction.

  The expanding portion 71 of the shielding member 70 is extended from the large diameter portion 31C of the inner ring 31 of the annular support member 30 surrounding the stopper piece 40 facing the front end surface of the small diameter fitting portion 62 of the boot 60 in the radial direction. Expands to approximately the same diameter as the large-diameter mounting portion 61 (in this embodiment, larger diameter than the large-diameter mounting portion 61), faces the front surface of the large-diameter mounting portion 61, and fits the boot 60 with a small diameter in the axial direction. It extends to a position surrounding at least a part of the portion 62. 71 A of outer peripheral surfaces of the expansion part 71 make the taper shape diameter-expanded toward back. The taper-shaped outer peripheral surface 71A of the expanding portion 71 starts to expand from the large-diameter portion 31C. The diameter is larger than the outer diameter of the tip 51B).

  The inner peripheral surface 71B of the expanded portion 71 also has a tapered shape that increases in diameter from the large diameter portion 31C toward the rear.

  When the small-diameter fitting portion 62 of the boot 60 includes only the fitting tube portion 62A and does not include the sealing tube portion 62B, the axially extending end of the expanding portion 71 of the shielding member 70 is connected to the fitting tube portion 62A. It is set so as to surround the rear end portion beyond the front end (free end).

According to the present embodiment, the following operational effects can be obtained.
(a) The shielding member 70 provided on the annular support member 30 that supports the center bearing 25 covers the periphery of the small-diameter fitting portion 62 to the inner 23 of the boot 60 in the radial direction and the axial direction, and shields this from the outside. This prevents intrusion of water or the like from the outside into the communication passage 64 for adjusting the internal pressure provided in the small diameter fitting portion 62.

  (b) When the shielding member 70 covers the small-diameter fitting portion 62 of the boot 60 in the radial direction and the axial direction, the shielding member 70 expands to approximately the same diameter as the large-diameter mounting portion 61 of the boot 60. It faces the front surface of the large-diameter mounting portion 61. Accordingly, the outside air that flows around the universal joint 20 from the front to the rear is guided outwardly by the outer periphery of the expanding portion 71 of the shielding member 70 so as to be largely separated from the small-diameter fitting portion 62 of the boot 60. The periphery of the large-diameter mounting portion 61 flows away backward. This prevents water or the like caught in the flow of ambient air around the universal joint 20 from entering the small diameter fitting portion 62 of the boot 60 and entering the communication passage 64 for adjusting the internal pressure.

  (c) Since the shielding member 70 is integrally formed with the annular support member 30, it is possible to improve the manageability and assembly of the shielding member 70.

  The embodiment of the present invention has been described with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. Included in the invention. For example, the shielding member may be provided on the outer ring of the annular support member. In addition, the shielding member may be formed separately from rubber or synthetic resin and later attached to the annular support member (adhesion, press-fitting, etc.). In this case, the deterioration of the assemblability due to the enlargement of the annular support member is avoided. Thus, the rust prevention and light weight of the shielding member can be improved.

FIG. 1 is a cross-sectional view showing a structure for preventing water and the like from entering the universal joint boot. FIG. 2 is an enlarged view of a main part of FIG.

Explanation of symbols

20 Universal joint 21 Outer (member to be mounted)
23 Inner (attached member)
25 Center bearing 30 Annular support member 50 Connection space 60 Boot 61 Large diameter mounting portion 62 Small diameter fitting portion 64 Communication path 70 Shielding member

Claims (4)

When one end of the boot that seals the connection space of the universal joint is fitted and attached to the attached member, a communication passage is provided to connect the inside and outside of the boot to the fitting portion of the boot to the attached member.
In the structure for preventing intrusion of water and the like of the universal joint boot formed by supporting the center bearing loaded on the side of the fitting portion of the boot in the mounted member on the annular support member,
A structure for preventing intrusion of water or the like of a universal joint boot, characterized in that a shielding member for covering the fitting portion of the boot in the radial direction and the axial direction is provided on the annular support member.   A small-diameter fitting portion at one end of the boot is attached to one attached member, a large-diameter attaching portion at the other end of the boot is attached to the other attached member, and the small-diameter fitting portion of the boot is attached by the shielding member. 2. The universal joint according to claim 1, wherein the shielding member expands to substantially the same diameter as the large-diameter mounting portion of the boot and faces the front surface of the large-diameter mounting portion when covering the diametrically and axially. Structure that prevents water from entering the boots.   The structure for preventing intrusion of water or the like in a universal joint boot according to claim 1 or 2, wherein the shielding member is formed integrally with an annular support member.   The structure for preventing intrusion of water or the like in the boot for a universal joint according to claim 1, wherein the shielding member is formed of rubber or synthetic resin.

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