JP2019015346A - Slide-type constant velocity universal joint - Google Patents

Abstract

To prevent external leakage of a lubricant, to suppress increase of joint internal pressure, and to prevent deformation and abrasion breakage of a boot.SOLUTION: In a slide-type constant velocity universal joint which includes an outer joint member 11, and an inner joint member 12 transmitting rotation torque while permitting axial displacement and angular displacement through a ball 13 between itself and the outer joint member 11, and in which a lubricant 27 is sealed in the outer joint member 11, and a small-diameter end portion 34 of a boot 28 closing an opening portion of the outer joint member 11 is mounted on a shaft 21 extended from the inner joint member 12, a lip portion 41 keeping a non-contact state to an outer peripheral face of the shaft 21 when the inner joint member 12 is positioned on a joint center, and kept into contact with the outer peripheral face of the shaft 21 when the inner joint member 12 is axially displaced to a joint depth side, is disposed on an inner peripheral face of an intermediate portion 35 of the boot 28.SELECTED DRAWING: Figure 1

Description

  The present invention is used in a power transmission system of an automobile or various industrial machines, and is incorporated in, for example, a propeller shaft or a drive shaft of an automobile, and includes a sliding constant velocity universal joint provided with a boot that prevents leakage of lubricant from the inside of the joint. About.

  For example, there are two types of constant velocity universal joints that are used as means for transmitting a 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, for example, there is a sliding type constant velocity universal joint disclosed in Patent Document 1.

  In this type of constant velocity universal joint, a lubricant such as grease is sealed inside, so that the lubricity at the sliding portion inside the joint is ensured during the operation of rotating while taking an operating angle. .

  Therefore, the constant velocity universal joint is provided with a large-diameter end of the boot at the opening end of the outer joint member and a shaft extending from the inner joint member in order to prevent leakage of the lubricant sealed inside the joint. It has a structure in which the small-diameter end is fastened and fixed by a boot band.

  The boot mounted on the constant velocity universal joint disclosed in Patent Document 1 has a structure in which a lip portion that comes into contact with the outer peripheral surface of the shaft is provided on the inner peripheral surface of the small-diameter end portion separately from the fastening and fixing portion by the boot band. It comprises.

  As described above, by providing the lip portion that exhibits the sealing function, the sealing performance by the boot is improved, so that the leakage of the lubricant enclosed in the joint is surely prevented.

JP 2006-308075 A JP 2011-153621 A

  By the way, in the constant velocity universal joint disclosed in Patent Document 1, the lip portion provided at the small-diameter end portion of the boot prevents the lubricant filled in the outer joint member from leaking to the outside, and has a sealing property. Has improved.

  However, since the propeller shaft to which the constant velocity universal joint is assembled rotates at a high speed, the internal pressure of the joint may increase due to heat generation during the high speed rotation, or the boot life may be reduced due to deterioration due to heat generation.

  In order to solve this problem, the applicant of the present invention, for example, for the purpose of preventing external leakage of the lubricant and preventing an increase in joint internal pressure and a decrease in boot life, is disclosed in Patent Document 2, for example. A dynamic constant velocity universal joint has been proposed first.

  In the sliding type constant velocity universal joint disclosed in Patent Document 2, a lip portion that contacts the outer peripheral surface of the shaft is formed on the outer joint member side portion of the inner peripheral surface of the end of the boot, and the inner and outer sides of the boot are communicated. A structure is provided in which a ventilation groove is formed in a part on the side opposite to the outer joint member of the inner peripheral surface of the end of the boot.

  In this sliding type constant velocity universal joint, the lip portion contacts the outer peripheral surface of the shaft, so that the lubricant filled in the outer joint member can be prevented from leaking to the outside, and sufficient sealing performance is ensured. can do.

  In addition, by connecting the inside and outside of the boot through the ventilation groove formed on the inner peripheral surface of the end of the boot, it is possible to suppress an increase in joint internal pressure due to heat generation during high-speed rotation of the joint, and to reduce the life of the boot. Can be prevented.

  However, in the sliding type constant velocity universal joint disclosed in Patent Document 2, since the lip portion is always in contact with the outer peripheral surface of the shaft, the internal pressure of the joint cannot be sufficiently adjusted, and the deformation and wear of the boot There is a risk of damage.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to prevent the external leakage of the lubricant and suppress the rise of the joint internal pressure, thereby preventing the deformation and wear damage of the boot. An object of the present invention is to provide a sliding type constant velocity universal joint that can be prevented.

  The sliding type constant velocity universal joint according to the present invention is an inner joint member that transmits rotational torque while allowing axial displacement and angular displacement between the outer joint member and the outer joint member via a torque transmission member. And an end portion of a boot that encloses the lubricant in the outer joint member and closes the opening of the outer joint member is attached to a shaft extending from the inner joint member.

  As a technical means for achieving the above-mentioned object, when the inner joint member is located in the center of the joint, it is in a non-contact state with the outer peripheral surface of the shaft, and when the inner joint member is axially displaced toward the inner side of the joint, the shaft A lip portion in contact with the outer peripheral surface of the boot is provided on the inner peripheral surface of the boot.

  In the present invention, when the inner joint member is displaced in the axial direction toward the joint back side, the lip portion contacts the outer peripheral surface of the shaft, so that the lubricant filled in the outer joint member can be prevented from leaking to the outside. Sufficient sealing performance can be ensured.

  On the other hand, when the inner joint member is located at the joint center, the lip portion is not in contact with the outer peripheral surface of the shaft, so that the inside and outside of the boot communicate with each other through a gap between the lip portion and the outer peripheral surface of the shaft. It is possible to prevent the joint internal pressure from increasing due to heat generation during high-speed rotation of the joint, and to prevent the boot from being deformed and worn out.

  The lip portion in the present invention preferably has a structure that comes into contact with the outer peripheral surface of the shaft by deforming the bent portion of the boot so as to be close to the outer peripheral surface of the shaft when the inner joint member is displaced axially toward the inner side of the joint. .

  By adopting such a structure, the lip portion contacts the outer peripheral surface of the shaft when the inner joint member is axially displaced from the joint center to the joint back side, so that even if the lubricant approaches the lip portion, Leakage can be effectively prevented.

  In the present invention, a structure in which a ventilation groove communicating with the inside and outside of the boot is provided on the inner peripheral surface of the end of the boot is desirable.

  By adopting such a structure, the inside and outside of the boot communicate with each other through a ventilation groove provided on the inner peripheral surface of the end portion of the boot, so that the joint internal pressure is further prevented from increasing due to heat generation during high-speed rotation of the joint. be able to.

  In the present invention, a structure in which at least one or more air holes are provided in the shaft contact portion of the lip portion is desirable.

  If such a structure is adopted, when the inner joint member is axially displaced toward the joint back side, the inside and outside of the boot communicate with each other through the vent hole of the lip even if the lip contacts the outer peripheral surface of the shaft. As a result, it is possible to prevent the joint internal pressure from increasing due to heat generation during high-speed rotation of the joint.

  According to the present invention, when the inner joint member is axially displaced toward the joint back side, the lip portion contacts the outer peripheral surface of the shaft, so that the lubricant filled in the outer joint member leaks to the outside. Can be prevented, and sufficient sealing performance can be secured.

  On the other hand, when the inner joint member is located at the joint center, the lip portion is not in contact with the outer peripheral surface of the shaft, so that the inside and outside of the boot communicate with each other through a gap between the lip portion and the outer peripheral surface of the shaft. It is possible to prevent the joint internal pressure from increasing due to heat generation during high-speed rotation of the joint, and to prevent the boot from being deformed and worn out.

  As a result, it is possible to provide a highly reliable long-life sliding constant velocity universal joint that can prevent the external leakage of the lubricant and suppress the increase of the internal pressure of the joint, and can reliably prevent the deformation and wear damage of the boot. Can do.

It is a longitudinal section showing the whole double offset type constant velocity universal joint composition in an embodiment of the present invention. It is a cross-sectional view which shows the whole structure of the constant velocity universal joint of FIG. It is a longitudinal cross-sectional view which shows the state from which the inner joint member was axially displaced to the joint back side from the state of FIG. It is a longitudinal cross-sectional view which shows the state which the inner joint member further axially displaced from the state of FIG. 3 to the joint back side. (A) is a partial expanded sectional view which shows an example of a lip part, (B) is a partial enlarged sectional view which shows the other example of a lip part. It is sectional drawing which follows the PP line of FIG. 1, and is sectional drawing which shows a ventilation groove | channel. It is sectional drawing which follows the QQ line | wire of FIG. 1, (A) is a notch semicircular shaped ventilation hole, (B) is a notch rectangular-shaped ventilation hole, (C) is a notch V-shaped ventilation hole. (D) is sectional drawing which shows a through-hole-shaped ventilation hole. It is a partial expanded sectional view which shows a linear-shaped ventilation groove. It is a partial expanded sectional view which shows a bent ventilation groove.

  An embodiment of a sliding type constant velocity universal joint according to the present invention will be described below in detail with reference to the drawings.

  In the following embodiments, a slide incorporated with a propeller shaft used in an automobile and having a structure for transmitting rotational torque at a constant speed even when the two shafts of the driving side and the driven side are connected and the two shafts take an operating angle. The double offset type constant velocity universal joint which is one of the dynamic constant velocity universal joints will be exemplified.

  In the following embodiments, a case where the present invention is applied to a double offset type constant velocity universal joint will be described. However, the present invention can be applied to other sliding type constant velocity universal joints such as a cross groove type constant velocity universal joint and a tripod type constant velocity universal joint. Is also applicable.

  The sliding constant velocity universal joint (hereinafter simply referred to as a constant velocity universal joint) of the embodiment shown in FIGS. 1 and 2 includes an outer joint member 11, an inner joint member 12, and a plurality of balls that are torque transmission members. 13 and the cage 14 are main components.

  The outer joint member 11 has a substantially cylindrical shape with both ends opened, and linear track grooves 15 extending in the axial direction are formed at a plurality of positions in the circumferential direction of the cylindrical inner peripheral surface 16 at equal intervals. In the inner joint member 12, linear track grooves 17 extending in the axial direction in pairs with the track grooves 15 of the outer joint member 11 are formed at a plurality of positions in the circumferential direction of the spherical outer peripheral surface 18 at equal intervals.

  The ball 13 is interposed between the track groove 15 of the outer joint member 11 and the track groove 17 of the inner joint member 12 and transmits rotational torque. The cage 14 is interposed between the cylindrical inner peripheral surface 16 of the outer joint member 11 and the spherical outer peripheral surface 18 of the inner joint member 12 and holds the balls 13 accommodated in the pockets 19.

  In this embodiment, six balls 13 are illustrated, but the number of the balls 13 is arbitrary. Further, a shaft 21 is connected to the shaft hole 20 of the inner joint member 12 by spline fitting and is prevented from coming off by a retaining ring 22.

  The inner joint member 12, the ball 13, and the cage 14 are accommodated in the outer joint member 11 and constitute an internal component 23. The internal part 23 can be angularly displaced and axially displaced with respect to the outer joint member 11.

  An annular groove 25 is provided on the inner peripheral surface of the opening end 24 of the outer joint member 11, and a circlip 26 is fitted into the annular groove 25. With this structure, when the internal component 23 is displaced in the axial direction, the ball 13 interferes with the circlip 26 so that the amount of axial displacement of the internal component 23 is regulated to prevent a slide over.

  In the constant velocity universal joint configured as described above, when an operating angle is given between the outer joint member 11 and the inner joint member 12 by the shaft 21, the ball 13 held in the cage 14 is always at any operating angle. The operating angle is maintained within the bisectoral plane, and constant velocity between the outer joint member 11 and the inner joint member 12 is ensured.

  In this constant velocity universal joint, the outer joint member 11 is filled with a lubricant 27 such as grease (indicated by a dotted point in the drawing), whereby the shaft 21 is angularly displaced and axially displaced with respect to the outer joint member 11. While rotating, the lubricity at the sliding part inside the joint is ensured.

  On the other hand, in order to prevent leakage of the lubricant 27 sealed inside the joint and to prevent foreign matter from entering from the outside of the joint, a rubber or resin boot 28 and a metal A boot adapter 29 is attached, and a metal seal plate 31 is attached to the other opening end 30.

  The boot 28 has a large-diameter end 32 fixed by a boot adapter 29 attached to the open end 24 of the outer joint member 11 and a small-diameter end fixed by a boot band 33 to the shaft 21 extending from the inner joint member 12. 34, a large-diameter end portion 32, and a small-diameter end portion 34 are connected to each other, and a bent portion 35 that is deformable when the shaft 21 is displaced in the axial direction and angular displacement is formed.

  The boot adapter 29 includes a base end portion 37 fitted to the outer peripheral surface of the opening end portion 24 of the outer joint member 11 and a tip end portion 38 extending in the axial direction from the base end portion 37. The base end portion 37 is fixed to the groove portion 36 on the outer peripheral surface of the opening end portion 24 by caulking. A large-diameter end portion 32 of the boot 28 is fixed to the distal end portion 38 by caulking.

  The seal plate 31 includes a disc-shaped plate portion 39 and a flange portion 40 that is bent in the outer peripheral edge and extends in the axial direction. The seal plate 31 is attached by press-fitting the flange portion 40 to the inner peripheral surface of the opening end portion 30 of the outer joint member 11.

  In the constant velocity universal joint of this embodiment, the cross-sectional tongue protruding toward the outer peripheral surface of the shaft 21 over the entire inner peripheral surface of the bent portion 35 (the side close to the small diameter end portion 34) of the boot 28. A piece-like lip portion 41 is provided. The protruding length of the lip portion 41 is preferably about 0.5 mm to 4 mm, for example.

  The lip portion 41 is not in contact with the outer peripheral surface of the shaft 21 when the internal part 23 including the inner joint member 12 is positioned at the joint center (see joint center) (see FIG. 1). When it is axially displaced to the side (see FIGS. 3 and 4), it contacts the outer peripheral surface of the shaft 21. The joint center (joint center) means an axial position of the internal component 23 when the vehicle is parked on a flat road.

  That is, as shown in the enlarged view of FIG. 1, when the internal component 23 is located at the joint center, the lip portion 41 is not in contact with the outer peripheral surface of the shaft 21, and the inner peripheral portion of the lip portion 41 and the outer periphery of the shaft 21 are There is a gap m between the surfaces. The gap m is set to about 0.5 mm to 4 mm, for example.

  On the other hand, as shown in the enlarged views of FIGS. 3 and 4, when the internal part 23 is axially displaced toward the joint back side, the bent portion 35 of the boot 28 is deformed so as to be close to the outer peripheral surface of the shaft 21. The part 41 contacts the outer peripheral surface of the shaft 21. FIG. 3 shows a state in which the internal component 23 has moved to a substantially central position of the outer joint member 11. FIG. 4 shows a state in which the internal component 23 has moved to the innermost position of the outer joint member 11.

  In the constant velocity universal joint of this embodiment, when the internal part 23 is axially displaced toward the joint back side (see FIGS. 3 and 4), the lubricant 27 filled in the outer joint member 11 is deformed. The lip portion 41 comes into contact with the outer peripheral surface of the shaft 21 by the deformation of the bent portion 35 of the boot 28 before approaching the bent portion 35 of the boot 28 and entering the small diameter end portion 34 side.

  The contact of the lip portion 41 can prevent the lubricant 27 from entering the small diameter end portion 34 side of the boot 28. As a result, the lubricant 27 can be prevented from leaking to the outside, and sufficient sealing performance can be ensured.

  On the other hand, when the internal part 23 is positioned at the center of the joint (see FIG. 1), the lip portion 41 is not in contact with the outer peripheral surface of the shaft 21, so the gap m between the lip portion 41 and the outer peripheral surface of the shaft 21. The inside and outside of the boot 28 communicate with each other through the.

  Due to the non-contact state of the lip portion 41, it is possible to prevent the joint internal pressure from increasing due to heat generation during high-speed rotation of the joint. Further, the deformation and wear damage of the boot 28 can be prevented in advance.

  Here, the formation position of the lip portion 41 may be other than the portion shown in FIG. 1, and when the internal part 23 is axially displaced to the joint back side, the outer periphery of the shaft 21 is deformed by the deformation of the bent portion 35 of the boot 28. Any part that can contact the surface may be used. That is, as shown by the broken line in FIG. 1, the lip portion 41 can be formed from the folded portion n where the stress load is small to the small diameter end portion 34.

  Further, the lip portion 41 is brought into contact with the outer peripheral surface of the shaft 21 when the internal component 23 moves by 1/3 or more of the axial displacement amount from the joint center to the innermost position (state of FIG. 3). The formation position and size of the portion 41 are set. This setting can prevent the lubricant 27 from entering the small diameter end portion 34 side of the boot 28 even when the amount of the lubricant 27 enclosed is maximum.

  The internal part 23 is axially displaced from the joint center to the innermost position, and the lip portion 41 contacts the outer peripheral surface of the shaft 21 before the lubricant 27 enclosed in the outer joint member 11 contacts the boot 28. Therefore, it is possible to reliably prevent the lubricant 27 from entering the small diameter end portion 34 side of the boot 28.

  As shown in FIG. 5 (A), the lip portion 41 of this embodiment has a cross-sectional shape inclined toward the opening end portion 24 (see FIG. 1) of the outer joint member 11, but in FIG. As shown, the cross-sectional shape may be inclined toward the small diameter end 34 of the boot 28.

  Further, in the constant velocity universal joint of this embodiment, since the propeller shaft rotates at a high speed, the internal pressure of the joint is increased due to heat generation at the time of the high speed rotation, and the boot life is not reduced due to deterioration due to the heat generation. Therefore, as shown in FIG. 1, a minute ventilation groove 42 is provided on the inner peripheral surface of the small diameter end portion 34 of the boot 28 (fixed portion by the boot band 33) so as not to leak the lubricant 27.

  The ventilation groove 42 has a structure in which a ventilation path surrounded by the outer peripheral surface of the shaft 21 is formed. In this way, by making the inside and outside of the boot 28 communicate with each other by the ventilation groove 42, it is possible to prevent an increase in joint internal pressure and a decrease in the boot life due to the heat radiation action by the ventilation groove 42 during high-speed rotation.

  6 is a cross-sectional view taken along the line P-P in FIG. In this embodiment, as shown in FIG. 6, the case where one ventilation groove 42 is provided along the circumferential direction of the small-diameter end portion 34 of the boot 28 is illustrated, but in the circumferential direction of the small-diameter end portion 34 of the boot 28. Two or more ventilation grooves 42 may be provided along the number, and the number thereof is arbitrary.

  FIG. 7 is a cross-sectional view taken along the line QQ in FIG. In the constant velocity universal joint of this embodiment, a vent hole 43 is provided in the inner peripheral edge portion that is the shaft contact portion of the lip portion 41. Various forms of the vent holes 43 are possible, and those forms are illustrated in FIGS. 7 (A) to (D).

  Specifically, as the vent hole 43, a cutout semicircular shape as shown in FIG. 5A, a cutout rectangular shape as shown in FIG. 5B, and a cutout as shown in FIG. A V-shape and a through-hole shape as shown in FIG.

  Thus, by providing the vent hole 43 in the lip portion 41, it is possible to suppress an increase in the joint internal pressure due to heat generation at the time of high-speed rotation of the joint even in the lip portion 41. Can be prevented in advance.

  As in the case of the ventilation groove 42 described above, in this embodiment, the case where one ventilation hole 43 is provided along the circumferential direction of the lip portion 41 of the boot 28 is illustrated. Two or more vent holes 43 may be provided, and the number thereof is arbitrary.

  Further, during the transition from the state shown in FIG. 3 to the state shown in FIG. 4, the lip portion 41 is in contact with the outer peripheral surface of the shaft 21 and is sealed. it can.

  On the other hand, as shown in FIG. 4, when the lubricant 27 is in contact with the lip portion 41 as in the state where the internal component 23 is located at the innermost position of the outer joint member 11, The deformation is increased and the vent hole 43 of the lip 41 is closed.

  Thus, in the state of FIG. 4, the lip portion 41 and the vent hole 43 are completely closed, but the state in which the internal component 23 of FIG. 4 is located at the innermost position of the outer joint member 11 is long during operation. Since it does not occur over time, there is no effect on the increase in joint internal pressure.

  Therefore, even if the vent hole 43 is formed, the lubricant 27 can be prevented from leaking to the outside, and sufficient sealing performance can be ensured.

  In this embodiment, the vent hole 43 of the lip portion 41 and the vent groove 42 of the small diameter end portion 34 are formed at different phases (circumferential positions) in the circumferential direction of the shaft 21. For example, although the case where the ventilation groove | channel 42 shown in FIG. 6 and the ventilation hole 43 shown to FIG. 7 (A)-(D) are formed in the phase shifted 180 degrees is illustrated, the phase shift | offset | difference amount is arbitrary.

  Thus, by forming the vent hole 43 of the lip portion 41 and the vent groove 42 of the small diameter end portion 34 in different phases in the circumferential direction of the shaft 21, the amount of phase shift between the vent hole 43 and the vent groove 42 can be increased. The joint internal pressure can be adjusted accordingly.

  The ventilation groove 42 has a linear shape formed along the axial direction of the shaft 21 as shown in an enlarged manner in FIGS. By forming such a linear ventilation groove 42 along the axial direction of the shaft 21, the ventilation groove 42 can be easily manufactured.

  Further, as shown in FIG. 9, the ventilation groove 42 includes an inner groove portion 44 formed along the axial direction of the shaft 21 and an intermediate portion formed along the circumferential direction of the shaft 21 continuously to the inner groove portion 44. It may be in the form of a bent shape constituted by the groove 45 and the outer groove 46 formed along the axial direction of the shaft 21 continuously to the intermediate groove 45.

  By adopting such a configuration, even when the lubricant 27 reaches the ventilation groove 42, it is possible to easily suppress the lubricant 27 from leaking to the outside of the joint through the ventilation groove 42. FIG. 9 illustrates the case where the inner groove portion 44 and the outer groove portion 46 are formed in a phase shifted by 180 ° in the circumferential direction of the shaft 21, but the amount of phase shift is arbitrary.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

11 outer joint member 12 inner joint member 13 torque transmission member (ball)
21 Shaft 27 Lubricant 28 Boot 41 Lip part 42 Ventilation groove 43 Ventilation hole

Claims (4)

An outer joint member and an inner joint member that transmits rotational torque while allowing axial displacement and angular displacement through the torque transmission member between the outer joint member, and a lubricant is provided in the outer joint member. A sliding type constant velocity universal joint that encloses an end of a boot that encloses and closes an opening of the outer joint member, and is attached to a shaft extending from the inner joint member,
A lip portion that is not in contact with the outer peripheral surface of the shaft when the inner joint member is located at the center of the joint, and that contacts the outer peripheral surface of the shaft when the inner joint member is axially displaced toward the inner side of the joint; A sliding type constant velocity universal joint provided on the inner peripheral surface of the boot.   The lip portion is in contact with the outer peripheral surface of the shaft by deforming the bent portion of the boot so as to be close to the outer peripheral surface of the shaft when the inner joint member is axially displaced toward the inner side of the joint. Item 2. The sliding type constant velocity universal joint according to Item 1.   The sliding type constant velocity universal joint according to claim 1 or 2, wherein a ventilation groove that communicates the inside and outside of the boot is provided on an inner peripheral surface of an end of the boot.   The sliding-type constant velocity universal joint as described in any one of Claims 1-3 which provided the at least 1 or more vent hole in the shaft contact site | part of the said lip | rip part.

Images