JP2018112219A - Constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve lubricity in a sliding region between an outer joint member and an inner joint member.SOLUTION: A constant velocity universal joint is provided that comprises: an outer joint member 12 in which axially extending track grooves 19 are formed in a plurality of circumferential portions in an inner circumferential surface 20; an inner joint member 13 in which axially extending track grooves 21 forming pair with the track grooves 19 of the outer joint member 12 are formed in a plurality of circumferential portions in an outer circumferential surface 22: balls 14 interposed between the track grooves 19 of the outer joint member 12 and the track grooves 21 of the inner joint member 13; and a cage 15 interposed between the inner circumferential surface 20 of the outer joint member 12 and the outer circumferential surface 22 of the inner joint member 13. Recessed parts 29, 30 are provided in the inner circumferential surface 20 of the outer joint member 12 and in the outer circumferential surface 22 of the inner joint member 13, respectively and fiber-flocked parts 31, 32 where many fibers are flocked are formed in the surfaces of the recessed parts 29, 30, respectively.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a constant velocity universal joint 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.

  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 such as grease is sealed in the internal 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.

  On the other hand, the constant velocity universal joint described above includes a ball type using a ball as a torque transmission member (see, for example, Patent Document 1). This ball type constant velocity universal joint includes a cage in addition to an outer joint member, an inner joint member, and a ball.

  In this type of constant velocity universal joint, the outer joint member has a track groove extending in the axial direction on the inner peripheral surface. The inner joint member has a track groove formed on the outer peripheral surface in a pair with the track groove of the outer joint member and extending in the axial direction. The ball is interposed between the track groove of the outer joint member and the track groove of the inner joint member and transmits the rotational torque. The cage is interposed between the inner peripheral surface of the outer joint member and the outer peripheral surface of the inner joint member to hold the ball.

JP 2012-149754 A

  By the way, in the above-described ball type constant velocity universal joint, a lubricant is sealed in the inner space of the outer joint member so as to ensure lubricity at the sliding portion inside the joint when the joint is operated. .

  In particular, among the sliding parts inside the joint, the sliding part between the inner peripheral surface of the outer joint member and the outer peripheral surface of the cage, and the sliding part between the outer peripheral surface of the inner joint member and the inner peripheral surface of the cage, There are severe conditions. Therefore, it is desired to ensure lubricity by improving the retention of the lubricant at these sliding parts.

  Accordingly, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is to provide a constant velocity universal joint capable of improving the lubricity at the sliding portion between the outer joint member and the inner joint member. It is to provide.

  The constant velocity universal joint according to the present invention includes an outer joint member in which track grooves extending in the axial direction are formed at a plurality of locations in the circumferential direction of the inner peripheral surface, and a pair of track grooves of the outer joint member in the axial direction. Inner joint members having extended track grooves formed at a plurality of locations in the circumferential direction of the outer peripheral surface, a torque transmission member interposed between the track grooves of the outer joint member and the track grooves of the inner joint member, and the inner peripheral surface of the outer joint member And a cage interposed between the outer peripheral surfaces of the inner joint members.

  As a technical means for achieving the above-mentioned object, in the present invention, a recess is provided on at least one of the inner peripheral surface of the outer joint member and the outer peripheral surface of the inner joint member, and is made of a fiber material, a soft foam material, or a soft resin material. A flexible structure is formed in the recess.

  In the present invention, the flexible structure is formed in the concave portion provided on at least one of the inner peripheral surface of the outer joint member and the outer peripheral surface of the inner joint member, so that the sliding portion of the outer joint member and the cage can be moved during joint operation. The lubricant is held by the flexible structure at the sliding portion of the cage and the inner joint member.

  Therefore, on the inner peripheral surface of the outer joint member and the outer peripheral surface of the inner joint member, the lubricity is improved by improving the holding power of the lubricant, the durability is improved, and the low heat generation and high efficiency are achieved by reducing the slip resistance. Can be planned.

  The flexible structure in the present invention preferably has a structure that is a flocked portion in which short fibers are implanted in a state perpendicular to the surface of the recess. This structure can be realized by electrostatic flocking.

  By adopting such a structure, a large amount of short fibers can be densely implanted in a short time with respect to the inner peripheral surface of the outer joint member and the outer peripheral surface of the inner joint member.

  The flexible structure in the present invention preferably has a structure that is a flocked portion in which short fibers are implanted in a state inclined at a certain angle with respect to the surface of the recess. This structure can be realized by electrostatic spraying.

  If such a structure is employ | adopted, a large area can be covered with a small amount of short fiber by reducing the flocking density compared with the electrostatic flocking which is not sprayed. As a result, the amount of lubricant retained in the flocked portion increases, and the rotational torque can be reduced more effectively.

  According to the present invention, the lubricant is held by the flexible structure at the sliding portion of the outer joint member and the cage and the sliding portion of the cage and the inner joint member when the joint is operated. Therefore, on the inner peripheral surface of the outer joint member and the outer peripheral surface of the inner joint member, the lubricity is improved by improving the holding power of the lubricant, the durability is improved, and the low heat generation and high efficiency are achieved by reducing the slip resistance. Can be planned. As a result, a constant velocity universal joint having a high quality and a long life 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 the partial front view which looked at the outer joint member of FIG. 1 from the opening side. It is the partial front view which looked at the outer joint member of FIG. 1 from the inner peripheral surface side. It is the partial front view which looked at the inner joint member of FIG. 1 from the opening side of the outer joint member. It is a principal part enlarged front view of FIG. It is a block diagram for demonstrating the outline point of electrostatic flocking. (A) is an expanded sectional view of the flocked part formed by electrostatic flocking, (B) is an expanded sectional view of the flocked part formed by electrostatic spraying flocking.

  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 ball type fixed type constant velocity universal which is incorporated in a drive shaft for an automobile and connects two axes of a driving side and a driven side and transmits the rotational torque at a constant speed even if the two axes take an operating angle. A Rzeppa constant velocity universal joint, which is one of the joints, is illustrated. Before describing the characteristic configuration of this embodiment, the overall configuration of the constant velocity universal joint will be described.

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

  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, 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.

  The overall configuration of the constant velocity universal joint in this embodiment is as described above. The characteristic configuration of the constant velocity universal joint in this embodiment will be described in detail below.

  In the constant velocity universal joint of this embodiment, as shown in FIG. 1, the inner peripheral surface 20 (see FIGS. 2 and 3) of the outer joint member 12 and the outer peripheral surface 22 of the inner joint member 13 (see FIGS. 4 and 5). Are provided with recesses 29, 30 extending in the axial direction, and a flexible structure made of a fiber material, a soft foam material, or a soft resin material, for example, a plurality of fibers planted on the surfaces of the recesses 29, 30. Portions 31 and 32 are formed.

  The inner peripheral surface 20 of the outer joint member 12 and the outer peripheral surface 33 of the cage 15 and the inner peripheral surface 34 of the cage 15 and the outer peripheral surface 22 of the inner joint member 13 slide relative to each other. The flocked portions 31 and 32 are interposed in the sliding portion composed of the surface 20 and the outer peripheral surface 33 of the cage 15 and the sliding portion composed of the inner peripheral surface 34 of the cage 15 and the outer peripheral surface 22 of the inner joint member 13.

  Thus, by forming the flocked portions 31 and 32 on the surfaces of the recesses 29 and 30 of the outer joint member 12 and the inner joint member 13, the inner joint surface 20 of the outer joint member 12 and the outer peripheral surface 33 of the cage 15 are formed. Lubricant adheres to and is held on the sliding portions and the flocked portions 31 and 32 interposed in the sliding portions composed of the inner peripheral surface 34 of the cage 15 and the outer peripheral surface 22 of the inner joint member 13.

  Since the lubricant is held by the flocked portions 31 and 32, the sliding portion composed of the inner peripheral surface 20 of the outer joint member 12 and the outer peripheral surface 33 of the cage 15, and the inner peripheral surface 34 and the inner joint member of the cage 15. Since the lubricant is not supplied from the flocked portions 31 and 32 to the sliding portion composed of the 13 outer peripheral surfaces 22 and the oil film is not cut off, the sliding resistance generated at the sliding portion is reduced.

  Due to the reduction of the slip resistance, the sliding portion composed of the inner peripheral surface 20 of the outer joint member 12 and the outer peripheral surface 33 of the cage 15 and the sliding portion composed of the inner peripheral surface 34 of the cage 15 and the outer peripheral surface 22 of the inner joint member 13 are achieved. Heat generation at the site can be reduced, and high efficiency and durability can be improved.

  The flocked portions 31 and 32 are formed by implanting short fibers on the surfaces of the concave portions 29 and 30 of the outer joint member 12 and the inner joint member 13. As the flocking method, electrostatic flocking or electrostatic spraying flocking can be employed. These methods are preferable in that a large amount of fibers can be densely implanted in a short time on the surfaces of the recesses 29 and 30 of the outer joint member 12 and the inner joint member 13.

  Electrostatic flocking includes an adhesive application process, an electrostatic flocking process, a drying process, a finishing process, and the like. The electrostatic flocking process is shown in FIG. In electrostatic flocking, the adhesive layer 40 is formed by applying an adhesive on the surfaces (represented as flat surfaces for the sake of convenience) of the recesses 29 and 30 of the outer joint member 12 and the inner joint member 13 that are objects to be flocked. Then, an electrostatic field is created by the high voltage electrode 42, and the short fibers 41 are raised on the adhesive layer 40 by the electrostatic attraction force. Then, the drying process which dries the adhesive agent of the contact bonding layer 40 is performed, and the finishing process which performs hair removal etc. next is performed.

  In the electrostatic flocking process, short fibers 41 cut to a predetermined size (the surface of which an electrolyte or surfactant film is formed, that is, the electrodeposition treatment agent is coated) are introduced in the vicinity of the high voltage electrode 42. To do. With this input, the short fiber 41 is attracted to the high voltage electrode 42 by Coulomb force. When the short fiber 41 touches the high voltage electrode 42, it is charged to the same potential as the electrode and is repelled by Coulomb force. Since the short fiber 41 is given a high potential, it flies toward the ground side.

  At this time, since the adhesive layer 40 is formed on the surfaces of the recesses 29 and 30 of the outer joint member 12 and the inner joint member 13 on the ground side, the short fibers 41 are pierced into the adhesive layer 40. In this way, the short fibers 41 are implanted in the surfaces of the recesses 29 and 30 of the outer joint member 12 and the inner joint member 13, and the flocked portions 31 and 32 are recessed portions 29 and 30 of the outer joint member 12 and the inner joint member 13. Formed on the surface.

  FIG. 7A illustrates the flocked portions 31 and 32 formed by electrostatic flocking. FIG. 7B illustrates the flocked portions 31 and 32 formed by electrostatic spraying flocking. In addition, in the same figure, although the surface of the recessed parts 29 and 30 of the outer joint member 12 and the inner joint member 13 which are flocking objects is a curved surface, it represents as a flat surface for convenience.

  In electrostatic flocking, as shown in FIG. 7A, the short fibers 41 are implanted in a state perpendicular to the surfaces of the recesses 29 and 30 of the outer joint member 12 and the inner joint member 13. In contrast, in electrostatic spraying flocking, as shown in FIG. 7B, unlike electrostatic flocking in which the short fibers 41 are vertically planted, the short fibers 41 are sprayed onto the adhesive application surface with air. Thus, the short fibers 41 are planted in an inclined state with respect to the surfaces of the recesses 29 and 30 of the outer joint member 12 and the inner joint member 13.

  For this reason, according to electrostatic spraying flocking, it is possible to cover a large area with a small amount of short fibers 41 by reducing the flocking density compared to electrostatic flocking that is not sprayed. In particular, the amount of lubricant retained by the flocking increases, and slip resistance can be reduced more effectively.

  The short fiber 41 used for flocking is not particularly limited as long as it can be used as a short fiber for flocking. For example, (1) polyolefin resin such as polyethylene and polypropylene, polyamide resin such as nylon, aromatic polyamide resin, polyethylene Polyester resin such as terephthalate, polyethylene naphthalate, polyethylene succinate, polybutylene terephthalate, synthetic resin fiber such as acrylic resin, vinyl chloride, vinylon, (2) inorganic fiber such as carbon fiber, glass fiber, (3) rayon, acetate And natural fibers such as cotton, silk, hemp and wool.

  These may be used alone or in combination of two or more. Lubricating or dissolving with oil is difficult to occur and is chemically stable, so that a large amount of homogeneous fibers can be produced and can be obtained at low cost. Therefore, it is preferable to use the synthetic resin fiber (1) among the above-mentioned (1) to (3).

  As the shape of the short fiber 41, in particular, as long as it is a shape that does not interfere with each other between the outer joint member 12 and the cage 15 and between the cage 15 and the inner joint member 13 in the formation portion of the flocked portions 31 and 32. It is not limited. As a specific shape, for example, those having a length of 0.5 to 2.0 mm and a thickness of 0.5 to 50 dtex are preferable, and the density of the short fibers 41 of the flocked portions 31 and 32 is about the area of flocking. The proportion of fibers is preferably 10 to 30%.

  The short fiber 41 has a straight shape or a bend (a shape in which the tip is bent), and has a circular or polygonal cross-sectional shape. The bend shape can hold the lubricant more strongly than the straight shape. By using the short fibers 41 having a polygonal cross section, the surface area can be larger than that of the circular cross section, and the surface tension of the lubricant can be increased. It is preferable to select the shape of the short fiber 41 according to each characteristic.

  Examples of the adhesive layer 40 include an adhesive mainly composed of urethane resin, epoxy resin, acrylic resin, vinyl acetate resin, polyimide resin, silicone resin, and the like. For example, urethane resin solvent adhesive, epoxy resin solvent adhesive, vinyl acetate resin solvent adhesive, acrylic resin emulsion adhesive, acrylate-vinyl acetate copolymer emulsion adhesive, vinyl acetate emulsion adhesive , Urethane resin emulsion adhesive, epoxy resin emulsion adhesive, polyester emulsion adhesive, ethylene-vinyl acetate copolymer adhesive and the like. These may be used independently and 2 or more types may be used together.

  In addition, in the above embodiment, when the flexible structure was comprised with the fiber material, ie, the flocked parts 31 and 32 in which many short fibers 41 were planted, the flexible structure was made into a soft foam material. Or you may comprise with a soft resin material. In that case, what is necessary is just to fix a flexible structure to the surface of the recessed parts 29 and 30 of the outer joint member 12 and the inner joint member 13 with an adhesive agent.

  Soft foam materials include those made by foaming synthetic resins such as polyurethane, polystyrene, polyolefin, phenol, and polyvinyl chloride, and rubbers such as natural rubber, chloroprene rubber, ethylene propylene rubber, nitrile rubber, silicon rubber, and styrene butadiene rubber. Can be mentioned. Examples of the soft resin material include cork materials, rubber plate materials, and soft sheets such as polyethylene and vinyl chloride.

  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)
15 Cage 19, 21 Track groove 20 Inner peripheral surface 22 Outer peripheral surface 29, 30 Recessed portion 31, 32 Flexible structure (planted portion)
33 Outer peripheral surface 34 Inner peripheral surface 41 Short fiber

Claims (3)

An outer joint member in which track grooves extending in the axial direction are formed at a plurality of locations in the circumferential direction of the inner peripheral surface, and a track groove extending in the axial direction in pairs with the track grooves of the outer joint member in the circumferential direction of the outer peripheral surface Inner joint members formed at a plurality of locations, a torque transmission member interposed between a track groove of the outer joint member and a track groove of the inner joint member, an inner peripheral surface of the outer joint member, and an outer periphery of the inner joint member A constant velocity universal joint with a cage interposed between the faces,
A recess is provided on at least one of an inner peripheral surface of the outer joint member and an outer peripheral surface of the inner joint member, and a flexible structure made of a fiber material, a soft foam material, or a soft resin material is formed in the recess. Constant velocity universal joint.   The constant velocity universal joint according to claim 1, wherein the flexible structure is a flocked portion in which short fibers are implanted in a state perpendicular to the surface of the concave portion.   2. The constant velocity universal joint according to claim 1, wherein the flexible structure is a flocked portion in which short fibers are implanted in a state inclined at a certain angle with respect to the surface of the concave portion.

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