JP2015021511A - Telescopic shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a telescopic shaft reduced in sliding resistance in relatively sliding a male shaft and a female shaft in an axial direction, and improved in abrasion resistance of an inclusion between the male shaft and the female shaft while assuming reduction of tooth hammering noise of the male shaft and the female shaft.SOLUTION: A telescopic shaft includes: a female shaft 2; and a male shaft 3 fitted to the female shaft 2, respectively having spline teeth 4, 5 engaged with each other in a shaft rotating direction and relatively slidable in an axial direction, and further includes a plurality of layers 7 for covering surfaces of the male spline teeth 5. The plurality of layers 7 respectively have fiber layers 9 composed of fiber impregnated with rubber or resin, and surface layers 10 covering surfaces of the fiber layers 9, slidably kept into contact with the female spline teeth 4, and composed of rubber or resin. The rubber or resin of the surface layers 10 has water repellency or/and oil repellency.

Description

  The present invention relates to a telescopic shaft in which a female shaft and a male shaft fitted in the female shaft have engaging teeth that engage with each other in the axial rotation direction, and can be slid relative to each other in the axial direction.

  As this type of telescopic shaft, for example, in Patent Document 1, a resin film made of a synthetic resin with a thickness of about 0.25 mm is provided on the surface of the spline, and the resin film is annealed to make the film thickness uniform. The illustrated telescopic shaft is disclosed.

  Patent Documents 2 and 3 disclose a telescopic shaft in which rubber or the like is interposed in a gap between a male spline and a female spline.

JP 2008-120250 A JP 2009-108892 A JP 2012-122610 A

  However, with the telescopic shaft disclosed in Patent Document 1, it is actually difficult to make the resin coating uniform even if annealing is performed, and rattling noise may occur in a thin portion of the resin coating. .

  Moreover, since the expansion-contraction shaft disclosed by the said patent documents 1-3 has resin or rubber interposed in the clearance gap between a male shaft and a female shaft, the relative sliding resistance to an axial direction increases.

  In addition, the resin or rubber interposed in the gap between the male shaft and the female shaft of the telescopic shaft disclosed in Patent Documents 1 to 3 can be easily obtained by repeated relative sliding in the axial direction of the male shaft and the female shaft. There is concern about wear.

  Therefore, the present invention reduces sliding resistance when the male shaft and the female shaft slide relative to each other in the axial direction while presupposing suppression of rattling noise between the male shaft and the female shaft. An object of the present invention is to provide a telescopic shaft having improved wear resistance of inclusions between the shaft and the female shaft.

  (1) The telescopic shaft of the present invention has engaging teeth that engage with each other in the axial rotation direction, a female shaft that can slide relative to the axial direction, and a male shaft that is fitted into the female shaft. And a plurality of layers covering the surface of the engaging teeth of the male shaft. The plurality of layers are a fiber layer made of fiber impregnated with rubber or resin, a surface layer made of rubber or resin that covers the surface of the fiber layer and is in sliding contact with the engaging teeth in the female shaft, It is characterized by having.

  According to the configuration of (1) above, the surface of the engaging teeth of the male shaft is covered with a plurality of layers, so that the rattling noise between the engaging teeth of the female shaft and the engaging teeth of the male shaft is suppressed. Is done. Further, among the plurality of layers, the surface layer is formed on the layer closest to the engaging tooth of the female shaft, and the fiber layer having low sliding resistance is formed immediately below the female shaft. The relative sliding resistance in the axial direction of the male shaft is reduced. In addition, since the fiber layer is covered with the surface layer, the possibility of the fibers in the fiber layer being cut by contact with the engaging teeth of the female shaft is reduced, and the durability and wear resistance of the fiber layer are reduced. Can be improved.

  (2) The telescopic shaft of the present invention has engaging teeth that engage with each other in the axial rotation direction, a female shaft that is slidable in the axial direction, and a male shaft that is fitted into the female shaft. , And a plurality of layers covering the surface of the engaging teeth of the female shaft. The plurality of layers are: a fiber layer made of fiber impregnated with rubber or resin; and a surface layer made of rubber or resin that covers the surface of the fiber layer and is in sliding contact with the engagement teeth of the male shaft. It is characterized by having.

  According to the configuration of (2) above, the surface of the engaging teeth of the female shaft is covered with a plurality of layers, so that rattling noise between the engaging teeth of the female shaft and the engaging teeth of the male shaft is suppressed. Is done. Further, among the plurality of layers, a surface layer is formed on a layer closest to the engagement tooth of the male shaft, and a fiber layer having a low sliding resistance is formed immediately below the layer. The relative sliding resistance in the axial direction of the male shaft is reduced. In addition, since the fiber layer is covered with the surface layer, the possibility of the fibers in the fiber layer being cut due to contact with the engagement teeth of the male shaft is reduced, and the durability and wear resistance of the fiber layer are reduced. Can be improved.

  (3) The telescopic shaft of the present invention is such that the rubber or resin constituting the surface layer has water repellency or / and oil repellency on the premise of having the structure of (1) or (2). It is characterized by.

  According to the configuration of (3) above, the surface layer has water repellency and / or oil repellency, so that infiltration of oil, grease, water, dust, etc. into the fiber layer is prevented, and deterioration of the fiber layer is prevented. Can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS The cross-sectional view of the expansion-contraction shaft which concerns on the 1st Embodiment of this invention, and its partial enlarged view are shown. The cross-sectional view of the expansion-contraction shaft which concerns on the 2nd Embodiment of this invention, and its partial enlarged view are shown.

[First Embodiment]
Hereinafter, the telescopic shaft according to the first embodiment of the present invention will be described with reference to the drawings. The telescopic shaft 1 illustrated in FIG. 1 is used, for example, as a steering shaft or an intermediate shaft of an automobile, and has engaging teeth that engage with each other in the axial rotation direction. The female shaft 2 and the male shaft 3 are mainly configured. In this embodiment, the female spline teeth 4 formed on the inner peripheral surface of the female shaft 2 and the male spline teeth 5 formed on the outer peripheral surface of the male shaft 3 are exemplified as the engagement teeth.

  The female shaft 2 is made of, for example, a rigid hollow shaft material such as metal, and has female spline teeth 4 on the periphery of the fitting hole 6. On the other hand, the male shaft 3 is made of a solid shaft material made of a rigid body such as metal, and has male spline teeth 5 formed corresponding to the female spline teeth 4 on the outer periphery thereof. The fitting hole 6 is fitted so as to be slidable in the axial direction. In addition, between the female shaft 2 and the male shaft 3, a gap for providing a coating layer 7 described later is secured in the rotational direction and the radial direction.

  On the surface of the male spline teeth 5 of the male shaft 3, a coating layer 7 composed of three layers is formed over the entire circumference. Of the coating layer 7, the base layer 8 made of rubber or resin covers the surface of the male spline teeth 5 of the male shaft 3 as the layer closest to the male shaft 3, and the surface of the base layer 8 is impregnated with rubber or resin. The fiber layer 9 made of the made fibers covers the surface, and the surface layer 10 made of rubber or resin covers the surface of the fiber layer 9. The base layer 8 is fixed to the surface of the male shaft 3, the fiber layer 9 is fixed to the surface of the base layer 8, and the surface layer 10 is fixed to the surface of the fiber layer 9. The thickness of the covering layer 7 composed of these three layers 8 to 10 can be set to be approximately the same as the gap size between the tooth surface 5a of the male spline tooth 5 and the tooth surface 4a of the female spline tooth 4, for example. However, the surface layer 10 is much thinner than the other layers 8 and 9 for the reason described later.

  A gap in the radial direction may be provided between the coating layer 7a stacked on the tip portion 5b of the male spline tooth 5 and the valley 2a between the female spline teeth 4. A radial gap may also be provided between the tip portion 4b of the female spline tooth 4 and the coating layer 7b stacked in the valley 3a between the male spline teeth 5. Both of these gaps may be provided, or only one of them may be provided.

  The base layer 8 is made of, for example, urethane rubber, nitrile rubber, silicon rubber, fluorine rubber, acrylic rubber, ethylene-propylene rubber, butyl rubber, isoprene rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, hydrogenated nitrile rubber, chloroprene rubber, polybutadiene. Rubber, styrene butadiene rubber, natural rubber, etc. alone or those modified in various ways, acrylic resin, polyester resin, urethane resin, vinyl chloride resin, polypropylene, polycarbonate, PET resin, fluorine resin, etc. Can be used.

  The fiber layer 9 can be formed of aramid fiber, nylon, urethane, cotton, silk, hemp, acetate, rayon, fluorine-containing fiber, polyester, and the like, and is impregnated with rubber or resin. The fiber shape may be, for example, a short fiber shape or a long fiber shape.

  By impregnating the fibers with rubber or resin, the rubber material or the resin material enters between the fibers, and the fibers are bonded together to function as the fiber layer 9. Further, when the fibers are impregnated with rubber or the like, wear due to rubbing between the fibers is reduced, and further, the wear resistance of the fiber layer 9 can be improved.

  In addition, the rubber | gum should just be what can impregnate a fiber. Examples of the rubber include urethane rubber, nitrile rubber, silicon rubber, fluorine rubber, acrylic rubber, ethylene-propylene rubber, butyl rubber, isoprene rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, hydrogenated nitrile rubber, chloroprene rubber, Polybutadiene rubber, styrene butadiene rubber, natural rubber, or the like can be used alone, or those obtained by variously modifying these rubbers. These rubbers can be used alone or in a blend of a plurality of types of rubbers. In addition to vulcanizing agents, rubbers that have been conventionally used as rubber compounding agents, such as vulcanization accelerators, anti-aging agents, softeners, plasticizers, fillers, and coloring agents, are used in appropriate amounts. Can be blended. Furthermore, instead of or together with the rubber, acrylic resin, polyester resin, urethane resin, vinyl chloride resin, polypropylene, polycarbonate, PET resin, fluororesin, polyethylene, AS resin, ABS resin, polystyrene resin, polyvinyl chloride Also, thermoplastic resins such as polyvinylidene chloride, polyvinyl acetate, nylon, alkyd resin, phenol resin, epoxy resin, polyphenylene sulfide resin, or thermosetting resin can be used.

  For the above-mentioned impregnation treatment of the fiber with rubber or resin, a method of dipping a predetermined fiber (short fiber, long fiber or cloth) after dissolving the rubber or resin with a solvent or the like to form a liquid is preferably used. . As a precursor of the fiber layer 9, a cloth in which fibers are formed in a sheet shape can be used. The method of impregnating the cloth with rubber or resin is also performed in the same manner as described above.

  Examples of what constitutes the fabric include a nonwoven fabric in which fibers are entangled irregularly, a regularly woven fabric, a knitted fabric (knit), and the like. Since these cloths are in the form of a sheet, they are characterized in that they can be easily impregnated with rubber or the like (easy to handle), and can easily adhere to the base layer 8 and the surface layer 10. For the weaving method, plain weave, satin weave, twill weave, or the like is used.

  Further, it is preferable that the cloth has a certain degree of elasticity. When the cloth is molded into a shape that conforms to the shape of the male spline teeth 5, the cloth surface is easily stretchable so that the surface of the cloth follows the shape of the male spline teeth 5. There is an advantage that wrinkles and the like are hardly generated and the surface is finished uniformly. As a result, axial sliding resistance generated between the male shaft 3 and the female shaft 2 can be further reduced. In particular, by producing the fiber layer 9 so that the direction of the stretchability of the cloth coincides with at least the circumferential direction of the substantially cylindrical fiber layer 9, the generation of wrinkles and the like can be further suppressed. .

  The surface layer 10 has water repellency or oil repellency in order to prevent water, grease, oil, dust and the like from entering the fiber layer 9. In order to develop a function of water repellency or / and oil repellency, it may be formed of a rubber or resin containing at least one of silicon resin, PTFE, urethane resin, acrylic silicone resin and fine particles thereof, or silicon. It may be formed of resin, PTFE, urethane resin or acrylic silicone resin itself. As a rubber or resin containing at least one of silicon resin, PTFE, urethane resin, acrylic silicone resin and fine particles thereof, for example, nitrile butadiene rubber can be considered. In order to develop water repellency or / and oil repellency, the ratio of the resin added to the rubber or resin is, for example, 5 wt% or more and less than 50 wt%, preferably 10 wt% or more and 30 wt% with respect to the rubber or resin 100. If there are few components that develop water repellency and oil repellency, the effect of water repellency and oil repellency will be small, and conversely if there are many components that express water repellency and oil repellency, adhesion to the fiber layer 9 will be poor, and the surface will be in use. There is a possibility that the layer 10 may be peeled off from the fiber layer 9.

  The surface layer 10 also serves to prevent the fibers contained in the fiber layer 9 from directly hitting the female spline teeth 4 (particularly, the edge portions of the female spline teeth 4) and being cut. Further, as the surface layer 10, it is desirable to adopt a thin layer as much as possible on the premise that a certain strength and durability are ensured in order to make use of the characteristics of the fiber layer 9 having a low frictional resistance.

(Operational effect of the telescopic shaft according to the first embodiment)
According to the above configuration, the thin surface layer 10 is formed on the layer closest to the female spline teeth 4 of the coating layer 7 formed on the surface of the male spline teeth 5, and the sliding resistance is low in the layer immediately below it. By forming the fiber layer 9, the relative sliding resistance in the axial direction of the female shaft 2 and the male shaft 3 is reduced, and the expansion and contraction of the telescopic shaft 1 can be performed smoothly. Further, since the surface layer 10 has water repellency and / or oil repellency, infiltration of oil, grease, water, dust and the like into the fiber layer 9 is prevented, and deterioration of the fiber layer 9 can be suppressed. Further, since the fiber layer 9 is covered with the surface layer 10, it is less likely that the fibers in the fiber layer 9 will be cut by contact with the female spline teeth 4. Abrasion is improved.

  Further, since the coating layer 7 including the fiber layer 9 and the like is interposed in the gap between the female spline teeth 4 and the male spline teeth 5, the rattling noise is suppressed and the female shaft 2 and the male shaft 3 Shaking in the axial rotation direction and the radial direction is suppressed, and further, stress concentration in the spline teeth 4 and 5 is also suppressed. Further, since the coating layer 7 is composed of a base layer 8 made of rubber or resin, a fiber layer 9 made of fiber impregnated with rubber or resin, and a surface layer 10 made of rubber or resin, the torsional initial stiffness The assembly work of the telescopic shaft 1 can be easily performed.

[Second Embodiment]
Hereinafter, a telescopic shaft according to a second embodiment of the present invention will be described with reference to the drawings. The telescopic shaft 11 illustrated in FIG. 2 is also used, for example, as a steering shaft or intermediate shaft of an automobile, and has engaging teeth that engage with each other in the axial rotation direction, and can slide relative to each other in the axial direction. The female shaft 12 and the male shaft 13 are mainly configured. Also in this embodiment, the female spline teeth 14 formed on the inner peripheral surface of the female shaft 12 and the male spline teeth 15 formed on the outer peripheral surface of the male shaft 13 are illustrated as the engagement teeth.

  Similar to the first embodiment, the female shaft 12 is made of, for example, a rigid hollow shaft material such as metal, and has female spline teeth 14 on the periphery of the fitting hole 16. On the other hand, like the first embodiment, the male shaft 13 is also made of a solid shaft material made of a rigid body such as metal, and has male spline teeth formed on the outer periphery thereof corresponding to the female spline teeth 14. 15 and is fitted into the fitting hole 16 of the female shaft 12 so as to be relatively slidable in the axial direction. A gap for providing a coating layer 17 described later is secured between the female shaft 12 and the male shaft 13 in the rotational direction and the radial direction.

  On the surface of the female spline teeth 14 of the female shaft 12, a coating layer 17 composed of three layers is formed over the entire circumference. Of the covering layer 17, as a layer closest to the female shaft 12, a base layer 18 made of rubber or resin covers the surface of the female spline teeth 14 of the female shaft 12, and the surface of the base layer 18 is impregnated with rubber or resin. The fiber layer 19 made of the formed fibers covers the surface, and the surface layer 20 made of rubber or resin covers the surface of the fiber layer 19. The base layer 18 is fixed to the surface of the female shaft 12, the fiber layer 19 is fixed to the surface of the base layer 18, and the surface layer 20 is fixed to the surface of the fiber layer 19. The thickness of the covering layer 17 composed of these three layers 18 to 20 can be, for example, approximately the same as the gap size between the tooth surface 15 a of the male spline tooth 15 and the tooth surface 14 a of the female spline tooth 14. However, the surface layer 20 is much thinner than the other layers 18 and 19 for the same reason as the surface layer 10 in the first embodiment.

  A radial gap may be provided between the coating layer 17a stacked on the tip portion 14b of the female spline tooth 14 and the valley 13a between the male spline teeth 15. A radial gap may also be provided between the tip portion 15b of the male spline tooth 15 and the coating layer 17b stacked in the valley 12a between the female spline teeth 14. Both of these gaps may be provided, or only one of them may be provided.

  The base layer 18, the fiber layer 19 and the surface layer 20 are the same as the base layer 8, the fiber layer 9 and the surface layer 10 described in the first embodiment, respectively, and their production methods are also the same.

(Effects of the telescopic shaft according to the second embodiment)
According to the above configuration, the thin surface layer 20 is formed on the layer closest to the male spline teeth 15 of the covering layer 17 formed on the surface of the female spline teeth 14, and the sliding resistance is low in the layer immediately below the layer 20. By forming the fiber layer 19, the relative sliding resistance in the axial direction of the female shaft 12 and the male shaft 13 is reduced, and the expansion / contraction of the expansion / contraction shaft 11 can be performed smoothly. Further, since the surface layer 20 has water repellency and / or oil repellency, infiltration of oil, grease, water, dust and the like into the fiber layer 19 is prevented, and deterioration of the fiber layer 19 can be suppressed. Further, since the fiber layer 19 is covered with the surface layer 20, there is a low possibility that the fibers in the fiber layer 19 will be cut by contact with the male spline teeth 15, and the durability and resistance of the fiber layer 19 are reduced. Abrasion is improved.

  Further, since the coating layer 17 including the fiber layer 19 and the like is interposed in the gap between the female spline teeth 14 and the male spline teeth 15, the rattling noise is suppressed and the female shaft 12 and the male shaft 13 Shaking in the axial rotation direction and the radial direction is suppressed, and furthermore, stress concentration in the spline teeth 14 and 15 is also suppressed. In addition, since the covering layer 17 is composed of a base layer 18 made of rubber or resin, a fiber layer 19 made of fiber impregnated with rubber or resin, and a surface layer 20 made of rubber or resin, the initial torsional rigidity The assembly work of the telescopic shaft 11 can be easily performed.

  As mentioned above, although 1st and 2nd embodiment of this invention was described based on drawing, it cannot be overemphasized that a specific structure is not limited to these embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above-described embodiment, an example in which the fibers of the “fiber layers 9 and 19” are impregnated with rubber or the like has been described. However, the present invention is not limited to this, and the fibers are formed using a cloth formed in a sheet shape Layers 9 and 19 may be formed. For example, canvas, velvet, denim, woven fabric, and knitted fabric impregnated with rubber or the like can be used. Moreover, you may employ | adopt the fiber which expands-contracts to the vertical / horizontal one side, or expands / contracts both to the vertical / horizontal side.

  In addition, the effects described above (for example, improvement of durability and wear resistance of the fiber layers 9 and 19, suppression of rattling noise, suppression of rattling in the axial rotation direction and radial direction, suppression of stress concentration in the spline teeth, The covering layers 7 and 17 are not necessarily fixed (adhered or the like) to the male shaft 3 or the female shaft 12 as long as the initial torsional rigidity can be reduced.

1,11 Telescopic shaft 2,12 Female shaft 3,13 Male shaft 4,14 Female spline teeth (engagement teeth)
5,15 Male spline teeth (engaging teeth)
7,17 Coating layer (multiple layers)
9,19 Fiber layer 10,20 Surface layer

Claims (3)

In a telescopic shaft comprising an engaging tooth that engages with each other in the axial rotation direction, a female shaft that is slidable relative to the axial direction, and a male shaft that is fitted into the female shaft,
A plurality of layers covering the surface of the engaging teeth of the male shaft;
The plurality of layers are:
A fiber layer made of fibers impregnated with rubber or resin;
A surface layer made of rubber or resin that covers the surface of the fiber layer and is in sliding contact with the engaging teeth in the female shaft;
A telescopic shaft characterized by comprising: In a telescopic shaft comprising an engaging tooth that engages with each other in the axial rotation direction, a female shaft that is slidable relative to the axial direction, and a male shaft that is fitted into the female shaft,
A plurality of layers covering the surface of the engaging teeth of the female shaft;
The plurality of layers are:
A fiber layer made of fibers impregnated with rubber or resin;
A surface layer made of rubber or resin that covers the surface of the fiber layer and is in sliding contact with the engaging teeth of the male shaft;
A telescopic shaft characterized by comprising: In the telescopic shaft according to claim 1 or 2,
The rubber or resin constituting the surface layer has water repellency and / or oil repellency, and an expansion and contraction shaft.