JP2018053926A - Constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the residence of a lubricant sealed in the inside of a joint at a cup bottom portion of an outside joint member.SOLUTION: A constant velocity universal joint is equipped with a cup-shaped outside joint member 12; and an inside joint member 13 which transmits rotation torque while permitting angle displacement through a ball 14 between the outside joint member 12 and the inside joint member 13. A lubricant is sealed in the inside of the outside joint member 12, and a shaft 17 is fitted in a shaft hole 16 of the inside joint member 13 so as to transmit torque. At a cup bottom portion 29 of the outside joint member 12, a recessed groove 30 stirring the lubricant is radially formed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a constant velocity universal joint 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 encloses a lubricant inside 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.

  The aforementioned constant velocity universal joint includes a cup-shaped outer joint member, an inner joint member, a ball and a cage, and a main portion, and has a structure in which a shaft is fitted in a shaft hole of the inner joint member so that torque can be transmitted. (For example, refer to Patent Document 1).

  This constant velocity universal joint has a structure in which a lubricant such as grease is sealed in the internal space of the outer joint member. By encapsulating this lubricant, the lubricity at the sliding part inside the joint, that is, the sliding part composed of the outer joint member, the inner joint member, the ball and the cage is ensured when the joint is operated. .

  In addition, this constant velocity universal joint has a rubber or resin bellows between the outer joint member and the shaft in order to prevent leakage of the lubricant sealed inside the joint and to prevent foreign matter from entering from the outside of the joint. The structure which mounted the boot-like.

JP2013-200000A

  By the way, generally, the lubricant sealed inside the joint tends to stay at the bottom of the cup of the outer joint member. Further, depending on the properties of the lubricant, there are some that are liable to harden under low or high temperature conditions, and in this case, the retention of the lubricant is more likely to occur.

  In order to solve this problem, the constant velocity universal joint disclosed in Patent Document 1 stirs the lubricant retained at the bottom of the cup of the outer joint member at the tip of the shaft exposed from the shaft hole of the inner joint member. The structure which attached the member is comprised.

  In a constant velocity universal joint employing such a structure, the stirring member that contacts the cup bottom of the outer joint member stays at the cup bottom of the outer joint member when the shaft takes an operating angle with respect to the outer joint member. Move the lubricant. Thus, the lubricant can be stirred by the movement of the lubricant by the stirring member, and the lubricity is improved.

  However, since the conventional constant velocity universal joint has a structure in which a stirring member separate from the shaft is attached to the tip of the shaft, the number of parts increases. Further, since the stirring member must be assembled to the shaft, an assembling process of the stirring member is required. As a result, the cost of the constant velocity universal joint is increased.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to make it possible to suppress the lubricant encapsulated inside the joint from staying at the cup bottom of the outer joint member. It is to provide a universal joint.

  A constant velocity universal joint according to the present invention includes a cup-shaped 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, A lubricant is sealed inside the outer joint member, and the shaft member is fitted into the shaft hole of the inner joint member so that torque can be transmitted.

  As a technical means for achieving the above-mentioned object, the present invention is characterized in that a concave groove or a convex for stirring the lubricant is provided in at least one of the cup bottom of the outer joint member and the tip of the shaft member. And

  Here, “at least one” means that the concave groove or convex portion is formed on the cup bottom of the outer joint member, the concave groove or convex portion is formed on the tip of the shaft member, and the concave groove or convex portion is It means a case where it is formed on both the cup bottom of the outer joint member and the tip of the shaft member.

  In the present invention, by providing a concave groove or a convex for stirring the lubricant at least one of the cup bottom of the outer joint member and the tip of the shaft member, the force for pushing out the lubricant with the acting force due to the rotation of the joint. The lubricant that stays at the bottom of the cup of the outer joint member can be stirred.

  The concave grooves or convex portions in the present invention preferably have a radial structure.

  By adopting such a structure, it becomes easy to push out the lubricant staying at the cup bottom of the outer joint member as the joint rotates.

  The concave groove or convex portion in the present invention preferably has a structure formed continuously or discontinuously along the radial direction.

  By adopting such a structure, it is easy to push out the lubricant that stays at the bottom of the cup of the outer joint member as the joint rotates, regardless of whether the concave groove or convex part is continuous or discontinuous. It becomes.

  According to the present invention, the concave groove or the convex portion for stirring the lubricant is provided on at least one of the cup bottom portion of the outer joint member and the tip portion of the shaft member. The pushing-out force works, the lubricant staying at the cup bottom of the outer joint member can be stirred, and the lubricity can be improved. Further, the cost of the constant velocity universal joint can be reduced with a simple assembly process without increasing the number of parts.

It is sectional drawing which shows the whole structure of a constant velocity universal joint in embodiment of this invention. FIG. 2 is a view taken in the direction of arrow X in FIG. 1. It is sectional drawing which follows the PP line | wire of FIG. It is a figure which shows the shape of a ditch | groove in other embodiment of this invention. It is a figure which shows the other shape of a ditch | groove in other embodiment of this invention. It is sectional drawing which shows the whole structure of a constant velocity universal joint in other embodiment of this invention.

  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.

  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.

  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.

  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 structure in which a rubber bellows-like boot 23 is mounted is provided.

  The boot 23 is fastened and fixed by the boot band 28 to the outer peripheral surface of the shaft 17 extending from the inner joint member 13 and the large-diameter end 24 fastened and fixed to the outer peripheral surface of the opening 11 of the outer joint member 12. The small-diameter end portion 25 is connected to the large-diameter end portion 24 and the small-diameter end portion 25, 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, it is preferable that the surface hardness is HDD 38-50. The resin boot is formed of, for example, a thermoplastic elastomer such as ester, olefin, urethane, amide, and styrene, and a composition containing the thermoplastic elastomer. In the case of resin boots, if the surface hardness is smaller than the HDD 38, the heat resistance is lowered, the cost of the boot is increased, and the strength is reduced. Conversely, if the surface hardness is larger than the HDD 50, the fatigue, flexibility and assembly are reduced. Incurs a decline in sex.

  When the boot 23 is made of rubber, the surface hardness is preferably Hs 50 to 70, and the rubber boot is formed of, for example, chloroprene rubber or silicon rubber. In the case of a rubber boot, if the surface hardness is smaller than Hs50, the strength of the boot 41 is reduced, and conversely, if the surface hardness is larger than Hs70, the fatigue property is reduced.

  Here, the lubricant encapsulated in the inner space of the outer joint member 12 is easily cured under low temperature and high temperature conditions depending on its properties, and is liable to stay at the cup bottom 29 of the outer joint member 12. The constant velocity universal joint has the following structure.

  FIG. 2 is a view taken in the direction of the arrow X in FIG. 1 and shows the cup bottom 29 of the outer joint member 12. As shown in the figure, the constant velocity universal joint of this embodiment has a structure in which, for example, a concave groove 30 is formed as a concave groove or a convex portion for stirring the lubricant on the cup bottom 29 of the outer joint member 12. . The concave groove 30 is formed at the same time when the outer joint member 12 is manufactured by forging. The concave grooves 30 are formed radially, and the cross-sectional shape thereof is, for example, V-shaped as shown in FIG.

  In the constant velocity universal joint in which the concave groove 30 is formed in the cup bottom 29 of the outer joint member 12, when the cup rotates by the clockwise action in FIG. The lubricant staying at the bottom 29 is pushed out (see the arrow in FIG. 3). In this way, the lubricant staying at the cup bottom 29 of the outer joint member 12 can be stirred.

  The lubrication of the constant velocity universal joint can be improved by stirring the lubricant in the concave groove 30. Further, since only the concave groove 30 is formed in the cup bottom 29 of the outer joint member 12, the number of parts is not increased. Furthermore, since there is no need to attach separate parts as in the prior art, the assembly process can be simplified. As a result, the cost of the constant velocity universal joint can be reduced.

  In this embodiment, the case where the cross-sectional shape of the concave groove 30 is V-shaped has been described. However, the present invention is not limited to this, and may be other shapes such as a U-shape.

  Moreover, in this embodiment, although it is set as the ditch | groove 30 continuously extended along a radial direction, as shown in FIG. 4, it can also be set as the ditch | groove 31 extended discontinuously along a radial direction. . Furthermore, the concave grooves 30 and 31 in this embodiment have a shape that linearly extends in the radial direction, but as shown in FIG. 5, the concave grooves 32 have a shape that extends in a curved line in the radial direction. May be.

  Furthermore, in the embodiment shown in FIG. 1, the case where the concave grooves 30 to 32 are formed in the cup bottom 29 of the outer joint member 12 has been described. However, the present invention is not limited to this, and as shown in FIG. 6. It may be a simple structure. In FIG. 6, the same parts as those of FIG.

  The constant velocity universal joint according to the embodiment shown in FIG. 6 has a structure in which a concave groove 34 is formed in the distal end portion 33 of the shaft 17 exposed from the shaft hole 16 of the inner joint member 13. The concave grooves 34 are also formed radially like the concave grooves 30 in the embodiment of FIG. 1, and the cross-sectional shape thereof is, for example, V-shaped (see FIG. 3).

  The concave groove 34 has a shape that extends continuously along the radial direction, but may have a shape that extends discontinuously along the radial direction (see FIG. 4). Moreover, although the ditch | groove 34 is a shape extended linearly toward a radial direction, the shape (refer FIG. 5) extended curvedly toward a radial direction may be sufficient.

  In the constant velocity universal joint in which such a concave groove 34 is formed in the tip portion 33 of the shaft 17, the lubricant staying at the cup bottom portion 29 is pushed out by the acting force due to the rotation of the shaft 17 during operation. In this way, the lubricant staying at the cup bottom 29 of the outer joint member 12 can be stirred.

  The lubrication of the constant velocity universal joint can be improved by stirring the lubricant in the concave groove 34. Further, since only the concave groove 34 is formed in the tip portion 33 of the shaft 17, the number of parts is not increased. Furthermore, since there is no need to attach separate parts as in the prior art, the assembly process can be simplified. As a result, the cost of the constant velocity universal joint can be reduced.

  In the above embodiment, although the concave grooves 30 to 32 and 34 are illustrated, the present invention is not limited to this, and may have various shapes including a convex portion.

  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)
16 Shaft hole 17 Shaft member (shaft)
29 Cup bottom part 30-32 Groove 33 Tip part 34 Groove

Claims (4)

A cup-shaped 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, and a lubricant is provided inside the outer joint member. A constant velocity universal joint sealed and fitted with a shaft member in a shaft hole of the inner joint member so that torque can be transmitted,
A constant velocity universal joint, wherein a concave groove or a convex portion for stirring the lubricant is provided in at least one of a cup bottom portion of the outer joint member and a tip portion of the shaft member.   The constant velocity universal joint according to claim 1, wherein the concave groove or the convex portion is formed in a radial shape.   The constant velocity universal joint according to claim 1, wherein the concave groove or the convex portion is continuously formed along a radial direction.   The constant velocity universal joint according to claim 1, wherein the concave groove or the convex portion is formed discontinuously along the radial direction.

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