JP2017026002A - Boot for constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boot for constant velocity universal joint capable of improving sealability and stably securing ventilation.SOLUTION: In a boot for constant velocity universal joint, a cylindrical shaft installation part is externally fitted to a shaft extending from an inside joint member of a constant velocity universal joint. At the shaft installation part, provided is a groove for ventilation passage that forms a communication passage communicating between the inside and outside of the joint in cooperation with the outer diameter surface of the shaft. Provided is a stopper receiving foreign matter on the outer end inner diameter side of the shaft installation part and preventing the foreign matter from entering the inside of the joint. The external opening part of the communication passage is provided on an outer diameter side with respect to the stopper part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a boot for a constant velocity universal joint, and in particular, a sealing device that is used in a power transmission system of an automobile or various industrial machines, and is incorporated in a propeller shaft of an automobile, for example, to prevent lubricant leakage from the inside of the joint. The present invention relates to a boot used for a constant velocity universal joint provided.

  For example, there are two types of constant velocity universal joints that are used as means for transmitting rotational force from an automobile engine to wheels at a constant velocity, a fixed constant velocity universal joint and a sliding constant velocity universal joint. Both of these constant velocity universal joints have a structure in which two shafts on the driving side and the driven side are connected so that rotational torque can be transmitted at a constant speed even if the two shafts have an operating angle.

  For example, as a constant velocity universal joint assembled to a propeller shaft used in an automobile such as a 4WD vehicle or an FR vehicle, there is a double offset type sliding constant velocity universal joint.

  As shown in FIG. 19, the double offset type sliding constant velocity universal joint includes an outer joint member 3 in which linear track grooves 1 extending in the axial direction are formed at a plurality of locations in the circumferential direction of the cylindrical inner peripheral surface 2. An inner joint member 6 in which linear track grooves 4 extending in the axial direction in pairs with the track grooves 1 of the outer joint member 3 are formed at a plurality of locations in the circumferential direction of the spherical outer peripheral surface 5; Ball 7 as a plurality of torque transmitting members interposed between the track groove 1 of the inner joint member 6 and the track groove 4 of the inner joint member 6, the cylindrical inner peripheral surface 2 of the outer joint member 3, and the inner joint member The cage 9 that holds the ball 7 accommodated in the pocket 8 interposed between the spherical outer peripheral surface 5 and the spherical outer peripheral surface 6 is a main component.

  A female spline 11 is formed on the inner diameter surface of the axial hole of the inner joint member 6, and the male spline 13 at the end of the shaft 12 is fitted into the axial hole. And the female spline 11 and the male spline 13 are fitted. A retaining ring 14 is attached to the female spline 11.

  One opening of the outer joint member 3 is sealed with a sealing device 15. The sealing device 15 is a boot with an adapter, and includes an elastic portion 16 made of a rubber material or a flexible resin material and a metal adapter 17. The elastic portion 16 includes a small-diameter end portion 16a fitted on the shaft 12, a large-diameter end portion 16b connected to the adapter 17, and a bellows-shaped bent portion 16c between the small-diameter end portion 16a and the large-diameter end portion 16b. Consists of. The small diameter end portion 16 a of the elastic portion 16 is fastened by a band 19 fitted in a circumferential groove 18 provided on the outer diameter surface of the small diameter end portion 16 a and is fixed to the shaft 12. The adapter 17 includes a caulking portion 17 a for caulking and fixing the large-diameter end portion 16 b of the elastic portion 16, and a fitting portion 17 b for externally fitting to the opening of the outer joint member 3.

  A circumferential recessed portion 20 and a circumferential recessed groove 21 are provided on the outer diameter surface of the opening of the outer joint member 3, and the end of the fitting portion 17b of the adapter 17 is crimped to the inner diameter side. The fastening portion 22 is fitted into the circumferential recessed portion 20. A seal member 23 such as an O-ring is fitted in the circumferential groove 21 of the outer joint member. Further, a circumferential groove 24 is provided in the inner diameter surface of the opening of the outer joint member 3, and a stopper 25 made of a ring body is fitted in the circumferential groove 24. That is, the stopper 25 prevents the internal component S (consisting of the inner joint member 6, the ball 7, the cage 8, and the like) accommodated in the outer joint member 3 from coming off from the outer joint member 3.

  As described above, in the sealing device provided with the elastic portion 16, the pressure inside the boot fluctuates due to changes in the atmospheric temperature during traveling of the vehicle, heat generation of the constant velocity universal joint itself, expansion of the boot due to centrifugal force, and the like. Thus, if it fluctuates, the elastic part 16 will be deformed excessively, and the durability of the elastic part 16 will decrease. Therefore, measures are taken for ventilation to prevent the elastic part from reversing or being damaged by the pressure inside the boot. As a countermeasure against this ventilation, a separate air vent pipe or a vent passage (vent passage) is provided at the shaft mounting portion (small diameter end) 16a of the elastic portion 16.

  That is, in the one shown in FIG. 19, as shown in FIGS. 21 to 25, a pair of ventilation grooves 26 extending in the axial direction are provided on the inner diameter surface of the small diameter end portion 16 a of the elastic portion 16. For this reason, the groove 26 and the outer peripheral surface of the shaft 12 form an air passage 27 (see FIG. 19) that communicates the inside and the outside of the elastic portion 16.

  With such a structure, as shown in FIG. 20, when the operating angle is taken, water droplets or the like are transmitted through the shaft 12, and the water droplet adhering portion W is formed at the small diameter end portion 16 a of the elastic portion 16. If accumulated in this way, when the pressure inside the boot falls, moisture or the like enters the boot via the air passage 27. In addition, there is a concern that rust on the shaft surface may hinder ventilation or increase the size of the inlet of the air passage so that water or the like can easily enter.

  For this reason, in order to satisfy the function for preventing the invasion of splash water, muddy water, and dust while ensuring the ventilation with the outside, there is a structure of an air passage and a structure for preventing the intrusion of muddy water and dust. Various proposals have been made in the past (Patent Documents 1 to 3).

  In Patent Document 1, a ventilation groove is formed on an inner diameter surface of a shaft mounting portion of a boot to form a ventilation path, and a boot cover that covers the shaft mounting portion is provided. In this case, the boot cover includes a mounting base portion that is fitted and fixed in an annular groove formed in the shaft, a cover cylindrical portion that expands from the mounting base stepwise to cover the shaft mounting portion of the boot, and the cover cylinder And a lip portion that extends from the portion and contacts the vicinity of the base portion of the shaft mounting portion. For this reason, by providing the boot cover, it is configured to prevent water droplets, dust, and the like from entering the boot from the opening of the ventilation groove.

  Patent Document 2 is provided with a ventilation groove that is inclined with respect to the axial direction of the shaft and has a bent portion. That is, a ventilation path that connects the inside and the outside of the boot is formed by the ventilation groove and the outer peripheral surface of the shaft. The partition walls that define the ventilation grooves are configured as a crush prevention means. By providing the crush prevention means, the ventilation cross-sectional area of the ventilation groove is secured.

  Patent Document 3 has an annular lip portion in a shaft mounting portion of a boot. A partial passage is formed in the inner peripheral surface of the annular lip portion, and the partial passage and the partial passage formed in the inner peripheral surface of the shaft mounting portion extend in the circumferential direction on the annular lip portion side of the shaft mounting portion. It communicates via a partial passage. In this case, the phase of the communication position between the partial passage of the annular lip portion and the partial passage extending in the circumferential direction is shifted from the communication position of the partial passage of the shaft mounting portion and the partial passage extending in the circumferential direction. For this reason, the partial passage of the shaft mounting portion, the partial passage of the annular lip portion, and the partial passage extending in the circumferential direction that communicates with each other form an air passage that communicates the inside and the outside of the boot. .

  In such a configuration, if the internal pressure of the boot rises, the air inside flows out through this air passage, and if the internal pressure of the boot decreases, it enters the inside of the boot through the air passage. Air can flow in. Moreover, if the propeller shaft rotates at a high speed, the boot swells due to centrifugal force, and the diameter of the tip of the annular lip increases. As described above, when the tip of the annular lip is enlarged, the tip of the annular lip comes into contact with the annular taper of the center bearing holding member disposed on the outer diameter side of the annular lip. Become. As a result, the opening of the air passage is closed, and the inflow of air from the outside is prevented.

Japanese Patent No. 4136699 Japanese Patent No. 4202092 Japanese Patent No. 4090801

  In the thing of patent document 1, the boot cover which is another member is required, and a number of parts will increase and it will invite a fall of assemblability. Also, the boot cover mounting base is fitted to the shaft. In this case, the boot cover is retracted from the boot shaft mounting portion, and the boot cover is closed after the boot band has been fastened to the boot shaft mounting portion. Is moved to the shaft mounting portion side. For this reason, the boot cover is not fastened with a boot band or the like, and since it is necessary to slide the boot cover along the shaft axis, the boot cover is attached to the shaft with a relatively weak force. Yes.

  For this reason, there is a possibility that the boot cover is displaced, and, as shown in FIG. 20, sewage or the like is transmitted to the outer end portion of the boot cover along the shaft to form a water droplet adhesion portion. In this case, it cannot be said that a sealing means is provided between the boot cover and the shaft, and if it accumulates in this way, there is a possibility that moisture may enter the boot.

  Moreover, in patent document 2, the penetration | invasion of muddy water etc. to the boot inside from the exterior is supposed by providing the ventilation groove which inclines with respect to the shaft-axis direction and has a bending part. However, in the case where the ventilation groove is inclined with respect to the axial direction of the shaft and has a bent portion, as shown in FIG. 20, when the water droplet adhesion portion is formed at the small diameter end portion (shaft mounting portion) of the boot. The reliability that can prevent moisture and the like from entering the boot through the air passage is low.

  In Patent Document 3, it is necessary to provide an annular lip portion at the small-diameter end portion (shaft mounting portion) of the boot, and to provide a tapered portion that receives the annular lip portion on the shaft, and further, a bearing that is fitted and fixed to the shaft. It is necessary to provide an annular taper portion corresponding to the annular lip portion on the center bearing holding member that holds the (center bearing). For this reason, in patent document 3, a structure becomes complicated, it is inferior to assemblability, and design free motion becomes low.

  Therefore, the present invention provides a boot for a constant velocity universal joint capable of improving sealing performance and ensuring stable ventilation.

  The constant velocity universal joint boot of the present invention is a constant velocity universal joint boot in which a cylindrical shaft mounting portion is fitted and fixed to a shaft extending from an inner joint member of the constant velocity universal joint. A vent channel groove is formed in cooperation with the outer diameter surface of the shaft to form a communication path that communicates the inside of the joint with the outside of the joint. A stopper for restricting the inflow of water is provided, and the external opening of the communication path is provided on the outer diameter side of the stopper. Here, the foreign matter is sewage, oil, dust or the like.

  According to the constant velocity universal joint boot of the present invention, the shaft mounting portion is provided with a ventilation channel groove for forming a communication path that communicates the inside of the joint and the outside of the joint. If it rises, the air inside flows out through this air passage, and when the internal pressure of the boot falls, the air can flow into the boot through the air passage. Even if foreign matter reaches the shaft mounting part through the shaft, it can be received by a stopper provided on the inner diameter side of the outer end of the shaft mounting part, preventing entry into the boot. I can do it.

  The stopper can be composed of a cylindrical lip extending in the axial direction along the outer diameter surface of the shaft. That is, the stopper can be formed with a simple configuration. In addition, a cylindrical outer flange portion extending in the axial direction is provided on the outer diameter side of the shaft mounting portion so as to face the lip, and the outside of the communication path is provided between the outer flange portion and the lip. An opening is preferably provided. As described above, in the case where the lip and the outer flange portion are provided, the external opening of the communication path is on the outer diameter side of the stopper constituted by the lip and on the inner diameter side of the outer flange portion. It will be located inward. For this reason, it protects so that the external opening part of a communicating path may not be exposed outside.

  Moreover, it is preferable that the axial length of the lip is longer than the axial length of the outer flange portion. If the axial length of the outer flange is longer than the axial length of the lip, foreign matter such as sewage received by the lip is blown to the outer diameter side by centrifugal force generated by the rotation of the shaft. It will be received at the outer arm. In such a case, foreign matters such as sewage enter the external opening of the communication path through the outer flange. On the other hand, if the axial length of the lip is made longer than the axial length of the outer flange portion, foreign matter such as sewage received by the lip is caused by centrifugal force generated by the rotation of the shaft, and the outer diameter side. When it is blown to the outside, it is not received by the outer casing portion, and foreign matters such as sewage can be prevented from entering the outer opening portion of the communication path through the outer casing portion.

  The boot may be composed of a ventilation structure portion having a ventilation channel groove and a stopper, and a boot body portion other than the ventilation structure portion. As described above, if the ventilation structure part which is a separate member is used for the boot body part, the boot body part can be an existing one which does not have the groove for the ventilation path, and the ventilation structure. As long as it has a groove for a ventilation path and a stopper as a part, it is excellent in productivity.

  In the present invention, a ventilation path that communicates the inside of the joint and the outside of the joint is provided, and furthermore, the entry of moisture into the boot can be regulated by a stopper provided on the outer diameter side of the shaft mounting portion. It is possible to control the pressure fluctuation inside the boot, and to prevent the entry of foreign matter such as splash water or muddy water into the boot, thereby improving the sealing performance. That is, it is possible to prevent intrusion of muddy water such as splash water and dust while ensuring ventilation with the outside. For this reason, the boot exhibits a stable sealing function over a long period of time, and can extend the life of the constant velocity universal joint.

It is sectional drawing of the constant velocity universal joint using the boot for constant velocity universal joints of this invention. It is principal part sectional drawing of the boot for constant velocity universal joints of FIG. FIG. 3 is a sectional view taken along line XX in FIG. 2. FIG. 3 is a view as seen from an arrow A in FIG. 2. It is an expanded view of the shaft mounting part of the boot for constant velocity universal joints of this invention. The shaft mounting part of the boot for constant velocity universal joints of this invention is shown, (a) is a perspective view which shows the linear groove | channel of a ventilation path, (b) is a perspective view which shows the external opening part of a ventilation path, c) is a perspective view showing a circumferential groove of an air passage. It is sectional drawing of the shaft mounting part at the time of making the axial direction length of a lip shorter than the axial direction length of an outer collar part. It is principal part sectional drawing which shows other embodiment of boots. It is sectional drawing of the shaft mounting part of the boot of a 1st reference example. FIG. 10 is a cross-sectional view taken along line X1-X1 of FIG. It is A1 arrow line view of FIG. FIG. 10 is a development view of the shaft mounting portion of the boot shown in FIG. 9. FIG. 10 shows a shaft mounting portion of the boot of FIG. 9, (a) is a perspective view showing a straight groove of the air passage, and (b) is a perspective view showing a circumferential groove of the air passage. It is sectional drawing of the shaft mounting part of the boot of a 2nd reference example. It is the X2-X2 sectional view taken on the line of FIG. It is A2 arrow line view of FIG. It is an expanded view of the shaft mounting part of the boot shown in FIG. 14 shows a shaft mounting portion of the boot of FIG. 14, (a) is a perspective view showing a straight groove of the air passage, and (b) is a perspective view showing a circumferential groove of the air passage. It is sectional drawing of the conventional constant velocity universal joint. FIG. 20 is a cross-sectional view of the constant velocity universal joint illustrated in FIG. It is sectional drawing of the shaft mounting part of the boot of the sealing device shown in FIG. It is X3-X3 sectional drawing of FIG. It is A3 arrow line view of FIG. It is an expanded view of the shaft mounting part of the boot shown in FIG. The shaft mounting part of the boot of FIG. 21 is shown, (a) is a perspective view which shows the linear groove | channel of a ventilation path, (b) is the perspective view seen from the end surface side.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. The constant velocity universal joint shown in FIG. 1 is a double offset type sliding type constant velocity universal joint, and linear track grooves 31 extending in the axial direction are formed at a plurality of locations in the circumferential direction of the cylindrical inner peripheral surface 32. An outer joint member 33 and an inner joint member 36 in which linear track grooves 34 extending in the axial direction in pairs with the track grooves 31 of the outer joint member 33 are formed at a plurality of locations in the circumferential direction of the spherical outer peripheral surface 35; A ball 37 that is a plurality of torque transmitting members that are interposed between the track grooves 31 of the outer joint member 33 and the track grooves 34 of the inner joint member 36, and the cylindrical inner peripheral surface 32 of the outer joint member 33. And a cage 39 holding the ball 37 accommodated in the pocket 38 interposed between the outer peripheral surface 35 and the spherical outer peripheral surface 35 of the inner joint member 36.

  In this case, the center of curvature O1 of the outer peripheral surface 39a of the cage 39 and the center of curvature O2 of the inner peripheral surface 39b are offset in the axial direction at equal intervals with respect to the angular center O of the joint. A female spline 41 is formed on the inner diameter surface of the axial hole of the inner joint member 36, and the male spline 43 at the end of the shaft 42 is fitted into the axial hole. The female spline 41 and the male spline 43 are fitted. A retaining ring 44 is attached to the female spline 41.

  One opening of the outer joint member 3 is sealed with a boot 45. The boot 45 is a boot with an adapter, and includes an elastic portion 46 made of a rubber material or a flexible resin material and a metal adapter 47. The elastic portion 46 includes a small-diameter end portion 46a that is externally fitted to the shaft 42, a large-diameter end portion 46b that is connected to the adapter 47, and a bellows-shaped bent portion 46c between the small-diameter end portion 46a and the large-diameter end portion 46b. Consists of. A band fitting concave groove 48 is formed on the outer diameter surface of the small diameter end portion 46 a of the elastic portion 46, and a boot band 49 is fitted into the band fitting concave groove 48 and tightened. As a result, the small-diameter end portion 46 a of the elastic portion 46 is fixed to the shaft 42. The adapter 47 includes a caulking portion 47 a for caulking and fixing the large-diameter end portion 46 b of the elastic portion 46, and a fitting portion 47 b for externally fitting to the opening of the outer joint member 33.

  Further, a circumferential recessed portion 50 and a circumferential recessed groove 51 are provided on the outer diameter surface of the opening of the outer joint member 33, and the end of the fitting portion 47b of the adapter 47 is crimped to the inner diameter side. The caulking portion 52 is fitted into the circumferential recessed portion 50. A seal member 53 such as an O-ring is fitted in the circumferential groove 51 of the outer joint member 33. A circumferential groove 54 is provided on the inner diameter surface of the opening of the outer joint member 33, and a stopper ring 55 made of a ring body is fitted in the circumferential groove 54. That is, the stopper ring 55 prevents the internal component S (consisting of the inner joint member 36, the ball 37, the cage 39, and the like) housed in the outer joint member 33 from coming off from the outer joint member 33.

  A small-diameter end portion 46a, which is a shaft mounting portion of the elastic portion 46, is formed with an air passage groove 56 for constituting an air passage 57 that communicates the inside and the outside of the elastic portion 46. As shown in FIGS. 2 to 6, the ventilation channel groove 56 includes a pair of linear grooves 56 a and 56 a on the inner side, a circumferential groove 56 b that communicates with the linear grooves 56 a and 56 a, and a circumferential direction A linear groove 56c extending in the axial direction from the groove 56b, a circumferential groove 56d that communicates with the linear groove 56c, and an opening groove 56e that communicates with the circumferential groove 56d and forms the opening 57a of the air passage 57 are provided.

  The circumferential groove 56b and the circumferential groove 56d are in contact with a position shifted by a predetermined pitch along the axial direction, and the linear grooves 56a, 56a and the linear groove 56c are out of phase. That is, as shown in FIG. 5 showing the development view, when the intermediate line between the linear grooves 56a and 56a is L1, and the center line of the linear groove 56c is L2, the intermediate line L1 and the center line L2 are It is shifted by 180 ° along the circumferential direction. The opening 56e is disposed on the intermediate line L1.

  As shown in FIG. 6, the small-diameter end portion 46a is provided with a stopper portion 58 that receives foreign matter on the inner diameter side of the outer end and restricts the inflow of foreign matter into the joint. The stopper portion 58 includes a short cylindrical lip 60 extending in the axial direction. Further, a short cylindrical outer flange portion 59 extending in the axial direction is provided on the outer end outer diameter side of the small diameter end portion (shaft mounting portion) 46 a so as to face the lip 60.

  Further, the outer diameter side of the stopper portion 58 and the inner diameter side of the outer flange portion 59, that is, between the stopper portion 58 and the outer flange portion 59, the outer edge of the stopper portion 58 and the outer flange. An external opening 57a (see FIG. 1 and the like) of the ventilation path 57 is formed at a position retracted inward from the outer edge of the portion 59.

  The axial length of the lip 60 constituting the stopper portion 58 is longer than the axial length of the outer flange portion 59. In this case, as shown in FIG. 2, the amount of protrusion (length in the axial direction) from the end surface of the opening 57a of the stopper portion 58 is H1, and the amount of protrusion from the end surface of the opening 57a of the outer collar portion 59 (axial direction) When the length) is H2, H1> H2, and the difference between H1 and H2 is preferably about 0.5 mm to 3.0 mm, for example. In addition, the radial distance H between the stopper portion 58 and the outer flange portion 59 is preferably about 0.5 mm to 2.0 mm, for example.

  Further, as the width dimension and the depth dimension of each of the grooves 56a, 56b, 56c, 56d, and 56e of the air passage groove 56, for example, as shown in FIG. 5, the width dimension of the linear groove 56a is W1, and the circumferential direction When the width dimension of the groove 56b is W2, the width dimension of the linear groove 56c is W3, the width dimension of the circumferential groove 56d is W4, and the width dimension of the opening groove 56e is W5, W1 is, for example, 0. 5 mm to 1.5 mm, W2 is, for example, about 0.5 mm to 1.0 mm, W3 is, for example, about 0.5 mm to 1.5 mm, and W4 is, for example, 0.5 mm to 1.0 mm. And W5 is, for example, about 0.5 mm to 1.5 mm.

  The depth dimension of the straight groove 56a is T1 (see FIGS. 2 and 3), the depth dimension of the circumferential groove 56b is T2 (see FIG. 3), and the depth dimension of the straight groove 56c is T3 (see FIG. 2). When the depth dimension of the circumferential groove 56d is T4 (see FIG. 3) and the depth dimension of the opening groove 56e is T5 (see FIG. 4), T1 is, for example, 0.5 mm to 1.5 mm. T2 is, for example, about 0.5 mm to 1.0 mm, T3 is, for example, about 0.5 mm to 1.5 mm, T4 is, for example, about 0.5 mm to 1.0 mm, and T5 is For example, about 0.5 mm to 2.0 mm.

  In addition, as the cross-sectional shape of each of the grooves 56a, 56b, 56c, 56d, and 56e of the air passage groove 56, various shapes such as a semicircle, a semi-ellipse or a semi-oval, a rectangle, and a semi-polygon can be selected.

  In the elastic part for a constant velocity universal joint according to the present invention, the stopper part 58 provided on the inner diameter side of the outer end of the shaft mounting part 46a can prevent entry of foreign matter such as muddy water and dust into the boot. In this case, since the external opening 57a of the air passage 57 is provided on the outer diameter side of the stopper portion 58, even if foreign matter reaches the shaft mounting portion 46a through the shaft 42, the air passage 57 It has a configuration in which foreign matter is extremely difficult to enter the external opening 57a. Further, the shaft mounting portion 57 is provided with a ventilation channel groove 56 for forming a communication path that communicates the inside of the joint with the outside of the joint. Therefore, if the internal pressure of the elastic portion 46 increases, this ventilation path When the internal air is caused to flow out through the air passage and the internal pressure of the elastic portion 46 is lowered, the air can be caused to flow into the elastic portion through the air passage.

  In the present invention, the air passage 57 that communicates the inside of the joint and the outside of the joint is provided, and the stopper portion 58 provided on the inner diameter side of the outer end of the shaft mounting portion 46a prevents foreign matter from entering the boot. Therefore, the pressure fluctuation inside the boot can be controlled, and foreign matter such as splash water and muddy water can be prevented from entering the boot, and the sealing performance can be improved. That is, it is possible to prevent intrusion of muddy water such as splash water and dust while ensuring ventilation with the outside. For this reason, the boot 45 having the elastic portion 46 exhibits a stable sealing function over a long period of time, and can extend the life of the constant velocity universal joint.

  The stopper portion 58 can be constituted by a lip 60 that extends in the axial direction along the outer diameter surface of the shaft 42. That is, the stopper portion 58 can be formed with a simple configuration. Further, an outer flange portion 59 extending in the axial direction is provided on the outer end outer diameter side of the shaft mounting portion 46 a so as to face the lip 60, and a communication path is provided between the outer flange portion 59 and the lip 60. An external opening is preferably provided. As described above, in the case where the lip 60 and the outer flange portion 59 are provided, the external opening 57a of the communication path is on the outer diameter side of the stopper portion 58 configured by the lip 60 and from the outer flange portion. Is also positioned inward in the axial direction on the inner diameter side. For this reason, it protects so that the external opening part 57a of the communicating path 57 may not be exposed outside.

  Incidentally, in the boot 45 shown in FIG. 7, the axial length H <b> 2 of the outer flange portion 59 can be set longer than the axial length H <b> 1 of the lip 60. However, if the axial length H2 of the outer flange portion 59 is longer than the axial length H1 of the lip, the foreign matter received by the lip 60 is caused by centrifugal force generated by the rotation of the shaft 42, and the outer diameter side. When it is skipped, it will be received at the outer brim 59. In such a case, there is a risk that water, dust, or the like, which is a foreign substance, may enter the external opening of the air passage through the outer flange 59. On the other hand, if the axial length of the lip 60 is made longer than the axial length of the outer flange portion, water drops received by the lip 60 are caused by the centrifugal force generated by the rotation of the shaft 42 and the outer diameter. When it is blown to the side, it is not received by the outer flange 59, and water and dust are prevented from entering the external opening 57a of the air passage 57 (see FIG. 1) via the outer flange 59. it can.

  Next, in FIG. 8, the elastic portion 46 includes a ventilation structure portion 61 having a ventilation path groove 56 and a stopper portion 58, and a boot body portion 62 other than the ventilation structure portion 61. That is, the ventilation structure portion 61 includes a main body portion 61a made of a small-diameter cylindrical body and a large-diameter portion 61b provided at the distal end portion of the main body portion 61a. The ventilation structure 61 is provided with a ventilation channel groove 56 for forming a ventilation channel 57. In addition, a lip 60 that constitutes the stopper portion 58 and an outer flange portion 59 are provided on the end surface of the large-diameter portion 61b. Then, the opening groove 56e opens between the lip 60 and the outer flange 59, and the opening 57a of the air passage 57 (see FIG. 1) is formed.

The small-diameter end 62a of the boot main body 62 has a cylindrical inner surface, and the ventilation structure 61
Is fitted and fixed to the main body 61a. As a result, an air passage groove 56 is formed in the shaft mounting portion 46a to form a communication path 57 (see FIG. 1) between the inside of the joint and the outside of the joint in cooperation with the outer diameter surface of the shaft 42 (see FIG. 1). In addition, a small-diameter end portion (shaft mounting portion) of the boot 46 provided with a stopper portion 58 that receives foreign matters and restricts the inflow of foreign matters into the joint on the outer end inner diameter side of the shaft mounting portion 46a is configured. In addition, the small-diameter end portion (shaft mounting portion) 46a of the elastic portion 46 has an outer casing extending in the axial direction so as to face the lip 60 constituting the stopper portion 58 on the outer end outer diameter side of the shaft mounting portion 46a. And an external opening 57 a of the communication passage 57 is disposed between the outer flange 59 and the lip 60.

  As described above, if the ventilation structure 61 that is a separate member is used for the boot body 62, the boot body 62 can be used without the ventilation channel groove 56. As the ventilation structure portion 61, any structure having the ventilation path groove 56 and the stopper portion 58 may be used, and the productivity is excellent.

  By the way, FIGS. 9-13 shows the 1st reference example, In this case, the ventilation path of the labyrinth structure is provided, without providing a stopper and an outer collar part. That is, as the air passage groove 71 for constituting the air passage, a pair of linear grooves 71a, 71a on the inner side, a circumferential groove 71b communicating with the linear grooves 71a, 71a, and the circumferential groove 71b And a linear groove 71c extending in the axial direction.

In this case, the phases of the linear grooves 71a and 71a and the linear groove 71c are shifted. That is, as shown in FIG. 12 showing the developed view, when the intermediate line between the straight grooves 71a and 71a is L1, and the center line of the straight groove 71c is L2, the intermediate line L1 and the center line L2 are It is shifted by 180 ° along the circumferential direction. That is, an air passage having a labyrinth structure is formed.

  In this case, the entire length of the air passage groove 71 constituting the air passage is made longer than that shown in FIG. 21 and the like, making it difficult for muddy water or the like to reach the inside of the boot. However, in this case as well, the water droplet adhering portion W is formed at the outer end portion located above the small diameter end portion 46a of the elastic portion 46, as in the case shown in FIG. If it accumulates in this way, moisture or the like will enter the boot through the air passage.

  FIGS. 14 to 18 show a second reference example. In this case, the air passage is constituted by the air passage groove 71 as shown in FIGS. 9 to 13, and the small diameter end portion of the elastic portion 46 is formed. 46a is provided with a short cylindrical lip 72 extending in the axial direction. That is, the lip 72 is provided on the outer diameter side of the opening portion 70a of the air passage, and mud water or the like flows into the opening portion 70a through the lip 72 so that the opening portion 70a is not exposed to the outside. It is difficult. However, even in this case, if the operating angle is taken, muddy water or the like may be accumulated in the lip 72. If accumulated in this way, moisture or the like enters the boot via the air passage.

  On the other hand, in this invention, as above-mentioned, muddy water etc. can be received in the stopper part 58, and the inflow into the ventilation path 57 can be prevented effectively.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications are possible. In the above embodiments, the double offset type sliding constant velocity universal joint (outside (Although angular displacement and axial displacement are allowed between the joint member and the inner joint member), other sliding type constant velocity universal joints of a cross groove type or a tripod type may be used. When the tripod type is used as the sliding constant velocity universal joint, it may be a single roller type or a double roller type. Also, it is not a sliding type constant velocity universal joint but a fixed type constant velocity universal joint such as a barfield type or undercut free type (a fixed type that allows only angular displacement between the outer joint member and the inner joint member). May be.

  When the boot is composed of two members as shown in FIG. 8, the ventilation structure 61 and the boot main body 62 may be made of the same material or different materials. These materials may be made of rubber such as chloroprene rubber, or may be made of resin using a thermoplastic elastomer material. Further, as a means for integrating the ventilation structure portion 61 and the boot body portion 62, various joining means such as adhesion, welding, or vulcanization can be used depending on the material used, the environment, and the like. Moreover, although the number of the openings 57a of the air passage 57 is one in the embodiment, a plurality of openings 57a may be provided. In this case, a plurality of opening grooves 56e may be provided.

33 Outer joint member 36 Inner joint member 45 Boot 46 Elastic portion 46a Small diameter end portion 55 Stopper ring 56 Air channel groove 57 Air channel 57a External opening 58 Stopper portion 59 Outer flange portion 60 Lip 61 Ventilation structure portion 62 Boot body portion

Claims (5)

A cylindrical shaft mounting portion is fitted and fixed to the shaft extending from the inner joint member of the constant velocity universal joint, and is fitted and fixed to the outer diameter surface of the opening portion of the outer joint member, and the opening portion of the outer joint member is sealed. A boot for a universal joint,
The shaft mounting portion is provided with a vent channel groove that forms a communication path that communicates the inside of the joint with the outside of the joint in cooperation with the outer diameter surface of the shaft, and receives foreign matter on the inner diameter side of the outer end of the shaft mounting portion. A constant velocity universal joint boot, characterized in that a stopper portion for preventing foreign matter from entering the inside of the joint is provided, and the external opening of the communication path is provided on the outer diameter side of the stopper portion.   2. The constant velocity universal joint boot according to claim 1, wherein the stopper portion includes a short cylindrical lip extending in an axial direction along an outer diameter surface of the shaft.   A short cylindrical outer flange portion extending in the axial direction is provided on the outer end outer diameter side of the shaft mounting portion so as to face the lip constituting the stopper portion, and is connected between the outer flange portion and the lip. The constant velocity universal joint boot according to claim 2, wherein an external opening of the passage is provided.   The constant velocity universal joint boot according to claim 2 or 3, wherein an axial length of the lip constituting the stopper portion is longer than an axial length of the outer flange portion.   The said boot consists of a ventilation structure part which has the groove | channel for ventilation paths, and a stopper part, and boot main-body parts other than this ventilation structure part, The Claim 1 characterized by the above-mentioned. Boots for constant velocity universal joints.

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