JP2018155375A - Constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhibit sufficient air cooling function at a close range to a joint, without increasing the number of components and manhours for assembly.SOLUTION: A constant velocity universal joint includes an outside joint member 12, and an inside joint member 13 configured to transmit rotational torque while allowing angular displacement through a ball 14 between itself and the outside joint member 12, wherein a large-diameter end part 24 of a boot 23 is mounted on the outside joint member 12 by a boot band 27, and a small-diameter end part 25 of the boot 23 is mounted on a shaft 17 extending from the inside joint member 13 by a boot band 28. On an outer peripheral surface of the boot band 28 mounted on the small-diameter end part 25 of the boot 23, a projection part 29 is provided.SELECTED DRAWING: Figure 1

Description

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

  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.

  A drive shaft that transmits power from the engine to the wheels needs to cope with angular displacement and axial displacement caused by a change in the relative positional relationship between the engine and the wheels. Therefore, the drive shaft is generally equipped with a sliding type constant velocity universal joint on the engine side (inboard side) and a fixed type constant velocity universal joint on the wheel side (outboard side). It has a structure in which universal joints are connected by a shaft.

  This type of constant velocity universal joint includes a cup-shaped outer joint member, an inner joint member, and a torque transmission member, and has a structure in which a lubricant is sealed in the inner space of the outer joint member. By enclosing the lubricant, the lubricity at the sliding portion inside the joint is ensured when the joint is operated.

  In this way, the constant velocity universal joint in which the lubricant is enclosed has a shaft extending from the outer joint member and the inner joint member in order to prevent the leakage of the lubricant from the inside of the joint and to prevent foreign matter from entering from the outside of the joint. A structure in which a rubber or resin boot is mounted is provided.

Japanese Utility Model Publication No. 62-63424 JP 2009-103216 A

  By the way, with the constant velocity universal joint described above, internal heat generation is likely to occur as the operating angle increases. Also, the higher the joint rotation speed, the more likely to generate internal heat.

  On the other hand, when such internal heat generation occurs, the boot may be damaged due to deterioration of the boot itself or expansion due to an increase in internal pressure of the boot.

  For the purpose of solving this problem, conventionally, in order to suppress internal heat generation of the joint, means for attaching a disk-shaped cooling fin to the outer joint member of the constant velocity universal joint and air-cooling the outer joint member (for example, Patent Document 1) and means for attaching a cooling fan to a damper attached to the shaft of the drive shaft and cooling the air (for example, refer to Patent Document 2) are taken.

  However, the means disclosed in Patent Document 1 requires a large number of steps when assembling the constant velocity universal joint because the number of parts increases in the assembly of the constant velocity universal joint.

  Further, in the means disclosed in Patent Document 2, the damper is attached at a position separated from the constant velocity universal joint because the attachment position of the damper is limited, and it is difficult to obtain a sufficient air cooling effect. is there.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to provide a sufficient air cooling effect at a short distance of the joint without increasing the number of parts and the number of assembly steps. The object is to provide a constant velocity universal joint.

  The constant velocity universal joint according to the present invention includes an outer joint member and an inner joint member that transmits rotational torque while allowing angular displacement between the outer joint member and the outer joint member via the torque transmission member. In addition, a structure is provided in which one end of the boot is mounted by a boot band, and the other end of the boot is mounted by a boot band on a shaft member extending from the inner joint member.

  As a technical means for achieving the above-mentioned object, the present invention is characterized in that a protrusion is provided on the outer peripheral surface of at least one of the boot bands attached to both ends of the boot.

  In the present invention, by providing a protrusion on the outer peripheral surface of at least one of the boot bands attached to both ends of the boot, the protrusion of the boot band that rotates during operation of the constant velocity universal joint is cooled. Functions as a fan. With the air blow to the boot by this protrusion, the internal heat generation of the constant velocity universal joint can be suppressed, and the boot itself can be prevented from being deteriorated or expanded due to an increase in the internal pressure of the boot.

  Thus, by providing a protrusion as a cooling fan on the outer peripheral surface of the boot band, a sufficient air cooling function can be exhibited at a short distance of the joint without increasing the number of parts and the number of assembly steps. .

  The protrusion in the present invention preferably has a plate shape and is arranged so as to be inclined with respect to the joint axial direction.

  By adopting such a structure, it becomes easy to blow air toward the boot by the protrusion of the boot band that rotates during operation of the constant velocity universal joint, and a further air cooling effect is obtained.

  The protrusions in the present invention preferably have a structure formed at a plurality of locations in the circumferential direction of the boot band.

  If such a structure is adopted, the air volume for cooling the boot can be increased by the protrusion of the boot band that rotates during operation of the constant velocity universal joint.

  The protrusion in the present invention preferably has a structure in which it is integrally formed by molding a part of the boot band.

  If such a structure is adopted, the protrusion as a cooling fan can be easily manufactured, and the protrusion can be formed on the outer peripheral surface of the boot band by simple means.

  According to the present invention, the protrusion of the boot band that rotates during operation of the constant velocity universal joint functions as a cooling fan. With the air blow to the boot by this protrusion, the internal heat generation of the constant velocity universal joint can be suppressed, and the boot itself can be prevented from being deteriorated or expanded due to an increase in the internal pressure of the boot.

  Thus, by providing a protrusion as a cooling fan on the outer peripheral surface of the boot band, a sufficient air cooling effect can be exhibited at a short distance of the joint without increasing the number of parts and the number of assembly steps. . As a result, a constant velocity universal joint with a long life and high reliability can be provided.

It is sectional drawing which shows the whole structure of a constant velocity universal joint in embodiment of this invention. It is an example of the projection part of a boot band, (A) is a side view which shows the projection part before a deformation | transformation, (B) is a side view which shows the projection part after a deformation | transformation. It is a perspective view which shows the other example of the protrusion part of a boot band. In other embodiment of this invention, it is a front view which shows the constant velocity universal joint which provided the projection part in the boot band of the boot both ends.

  An embodiment of a constant velocity universal joint according to the present invention will be described in detail below based on the drawings.

  In the following embodiments, a fixed type constant velocity universal joint that is incorporated in a drive shaft for an automobile, connects two shafts on the driving side and the driven side, and transmits rotational torque at a constant speed even when the two shafts have an operating angle. An example is a Rzeppa type constant velocity universal joint.

  The present invention can be applied to other fixed type constant velocity universal joints such as an undercut free type constant velocity universal joint in addition to the Rzeppa type constant velocity universal joint. Further, the present invention can also be applied to a sliding type constant velocity universal joint such as a tripod type, a double offset type, and a cross groove type constant velocity universal joint. Furthermore, the present invention can also be applied to a fixed type constant velocity universal joint and a sliding type constant velocity universal joint incorporated in an automobile propeller shaft.

  As shown in FIG. 1, a fixed type constant velocity universal joint (hereinafter simply referred to as a constant velocity universal joint) of this embodiment includes a cup-shaped outer joint member 12 having an opening 11, an inner joint member 13, torque transmission, and the like. The main part is composed of a plurality of balls 14 and a cage 15 which are members.

  This constant velocity universal joint has a structure in which an internal part composed of an inner joint member 13, a ball 14 and a cage 15 can be angularly displaced with respect to the outer joint member 12.

  One end of a shaft 17 that is a shaft member is connected to the shaft hole 16 of the inner joint member 13 so that torque can be transmitted by spline fitting. The shaft 17 extending from the inner joint member 13 is prevented from coming off from the inner joint member 13 by a retaining ring 18 fitted in a circumferential groove formed at the end of the shaft.

  In the outer joint member 12, arc-shaped track grooves 19 extending in the axial direction are formed at equal intervals in a plurality of locations in the circumferential direction of the spherical inner peripheral surface 20. In the inner joint member 13, arc-shaped track grooves 21 that extend in the axial direction in pairs with the track grooves 19 of the outer joint member 12 are formed at a plurality of positions in the circumferential direction of the spherical outer peripheral surface 22 at equal intervals.

  The ball 14 is interposed between the track groove 19 of the outer joint member 12 and the track groove 21 of the inner joint member 13 to transmit rotational torque. The cage 15 is disposed between the inner peripheral surface 20 of the outer joint member 12 and the outer peripheral surface 22 of the inner joint member 13 to hold the ball 14. The number of balls 14 may be 6, 8, or any number, and the number is arbitrary.

  In the constant velocity universal joint having the above-described configuration, a lubricant such as grease (not shown) is sealed in the inner space of the outer joint member 12, so that the sliding portion inside the joint, that is, the outer With respect to the joint member 12, the lubricity at the sliding portion of the internal part composed of the inner joint member 13, the ball 14 and the cage 15 is ensured.

  This constant velocity universal joint is made of resin between the opening 11 of the outer joint member 12 and the shaft 17 in order to prevent leakage of the lubricant enclosed in the joint and prevent foreign matter from entering from the outside of the joint. Alternatively, a seal structure equipped with a rubber bellows-like boot 23 is provided.

  The boot 23 includes a large-diameter end 24 fastened and fixed to the outer peripheral surface of the opening 11 of the outer joint member 12 by a boot band 27, and a small-diameter end 25 fixed to the outer peripheral surface of the shaft 17 by a boot band 28. The large-diameter end portion 24 and the small-diameter end portion 25 are connected to each other, and the telescopic bellows portion 26 is reduced in diameter from the large-diameter end portion 24 toward the small-diameter end portion 25.

  When the boot 23 is made of resin, the surface hardness is preferably HDD38-50. Examples of the material of the boot 23 include thermoplastic elastomers such as ester, olefin, urethane, amide, and styrene.

  If the surface hardness is smaller than that of the HDD 38, the heat resistance is reduced, the cost of the boot 23 is increased, and the strength is reduced. On the contrary, if the surface hardness is larger than that of the HDD 50, the fatigue property, flexibility, and assembling property are lowered.

  When the boot 23 is made of rubber, the surface hardness is preferably Hs 50 to 70. Examples of the material of the boot 23 include chloroprene rubber and silicon rubber.

  If the surface hardness is smaller than Hs50, the strength of the boot 23 is reduced. On the other hand, if the surface hardness is higher than Hs70, the fatigue property is reduced.

  In this embodiment, a boot mounting structure in which the small-diameter end 25 of the boot 23 is fastened and fixed to the shaft 17 by a metal boot band 28 will be described in detail below. Various types of boot band 28 can be used, such as those that can be fastened and fixed by caulking and those that can be fastened and fixed by lever operation. FIG. 1 shows a portion of the small diameter end portion 25 of the boot 23 in a side view, and shows the other portions in a sectional view.

  As shown in FIG. 1, the constant velocity universal joint of this embodiment has a structure in which a protrusion 29 is provided on the outer peripheral surface of a boot band 28 that fastens and fixes the small-diameter end 25 of the boot 23 to the outer peripheral surface of the shaft 17. To do. The protrusion 29 has a plate shape and is disposed so as to be inclined with respect to the joint axial direction. The protrusions 29 are formed at equal intervals at a plurality of locations in the circumferential direction of the boot band 28.

  Thus, by providing the protrusion 29 on the outer peripheral surface of the boot band 28, the protrusion 29 of the boot band 28 that rotates when the constant velocity universal joint is operated functions as a cooling fan. By blowing air to the boot 23 by the projection 29 as a cooling fan, internal heat generation of the constant velocity universal joint can be suppressed, and deterioration of the boot 23 itself and expansion due to an increase in internal pressure of the boot 23 can be prevented.

  Thus, by providing the protrusion 29 as a cooling fan on the outer peripheral surface of the boot band 28, a sufficient air cooling effect can be exhibited at a short distance of the joint without increasing the number of parts and the number of assembly steps. Can do.

  Further, since the plate-like protrusion 29 is disposed so as to be inclined with respect to the joint axial direction, air is blown toward the boot 23 by the protrusion 29 of the boot band 28 that rotates when the constant velocity universal joint is operated. (See the arrow in the figure), and a further air cooling effect is obtained. That is, the inclination direction of the protrusion 29 is arranged at an angle at which air is blown toward the boot 23 when the automobile is driven forward. Usually, internal heat generation is likely to occur in the forward operation, and in the reverse operation, the frequency is low and the possibility of internal heat generation is low.

  Further, since the protrusions 29 are formed at a plurality of locations in the circumferential direction of the boot band 28, the air volume for cooling the boot 23 is increased by the protrusions 29 of the boot band 28 that rotates when the constant velocity universal joint is operated. Can be made.

  As shown in FIG. 2 (A), the protrusion 29 described above is formed so that a part of the boot band 28 is polymerized by caulking, and as shown in FIG. It can be manufactured by being deformed so as to be inclined with respect to the joint axial direction.

  In addition, as shown in FIG. 3, it is also possible to manufacture the protrusion part 30 inclined with respect to the joint axial direction by cutting and raising a part of the boot band 28.

  In any case, by forming a part of the boot band 28 by caulking or cutting up, the protrusions 29 and 30 as a cooling fan can be easily manufactured. , 30 can be formed on the outer peripheral surface of the boot band 28.

  In the above embodiment, the case where the protrusions 29 and 30 are formed on the boot band 28 that fastens and fixes the small-diameter end portion 25 of the boot 23 to the outer peripheral surface of the shaft 17 is illustrated. The present invention is not limited to this, and as shown in FIG. 4, a boot band 27 that fastens and fixes the large-diameter end 24 of the boot 23 to the outer peripheral surface of the opening 11 (see FIG. 1) of the outer joint member 12. The protrusion 31 may be formed on the surface.

  In this case, it is desirable to arrange the inclination direction of the protrusion 31 of the boot band 27 at an angle that blows air toward the boot 23 when the automobile is driven forward. That is, it is desirable to arrange the protrusion 29 of the boot band 28 so as to be inclined in the direction opposite to the direction inclined with respect to the joint axial direction.

  Thereby, it becomes easy to blow air toward the boot 23 by the protrusion 31 of the boot band 27 that rotates during operation of the constant velocity universal joint (see the arrow in the figure). As described above, by providing the protrusions 31 and 29 on the boot bands 27 and 28 located at the both ends 24 and 25 of the boot 23, the air cooling effect is doubled.

  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.

12 outer joint member 13 inner joint member 14 torque transmission member (ball)
17 Shaft member
23 Boot 24 End (Large diameter end)
25 End (small diameter end)
27, 28 Boot band 29, 30, 31 Protrusion

Claims (4)

An outer joint member, and an inner joint member that transmits rotational torque while allowing angular displacement between the outer joint member and the outer joint member via a torque transmission member. A constant velocity universal joint mounted with a boot band on the other end of the boot on a shaft member extending from the inner joint member,
A constant velocity universal joint characterized in that a protrusion is provided on an outer peripheral surface of at least one of the boot bands mounted on both ends of the boot.   2. The constant velocity universal joint according to claim 1, wherein the protruding portion has a plate shape and is disposed so as to be inclined with respect to a joint axial direction.   The constant velocity universal joint according to claim 1, wherein the protrusion is formed at a plurality of locations in the circumferential direction of the boot band.   The constant velocity universal joint according to any one of claims 1 to 3, wherein the protrusion is integrally formed by molding a part of the boot band.

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