JP6038538B2 - Shaft structure, male member, and female member - Google Patents

Description

  The present invention relates to a shaft structure to be assembled to a shaft used in various industrial machines, and a male member and a female member constituting the shaft structure.

  2. Description of the Related Art Conventionally, for example, a telescopic shaft provided with a male spline shaft and a female spline shaft is known as a telescopic shaft for vehicle steering incorporated in a steering shaft of a vehicle (see FIG. 2 of Patent Document 1). In this telescopic shaft, splines are formed on the outer peripheral surface of the male spline shaft and the inner peripheral surface of the female spline shaft. Furthermore, a resin film made of a synthetic resin (nylon or the like) having a thickness of about 0.25 [mm] is formed on either the outer peripheral surface of the male spline shaft or the inner peripheral surface of the female spline shaft. Yes.

However, the telescopic shaft is a spline formed on the outer peripheral surface of the male spline shaft or the inner peripheral surface of the female spline shaft, so that the dimensional accuracy can be obtained from between the male spline shaft and the female spline shaft. There was a problem that an unpleasant noise called a rattling sound was generated.

  On the other hand, a torque transmission joint is known in which a rubber material such as nitrile rubber, silicon rubber, or urethane rubber is provided in a part of a gap between the male spline shaft and the female spline shaft (see FIG. 2 of Patent Document 2). ). This joint has a structure in which a spline shaft portion provided at a distal end portion of an output shaft of an electric motor and a spline hole provided at a proximal end portion of a worm shaft are spline-engaged. In this joint, the play between the male spline shaft and the female spline shaft is absorbed by the rubber material, and the rattling noise (tooth rattling sound) generated between the male spline shaft and the female spline shaft is suppressed. .

JP 2008-120250 A JP 2009-108892 A

  However, in the joint for torque transmission described in Patent Document 2, the sliding resistance in the axial direction between the male spline shaft and the female spline shaft can be reduced by providing a rubber material even though the above rattling noise can be suppressed. There was a problem that the sliding property deteriorated.

  Furthermore, in the torque transmission joint described in Patent Document 2, the contact area between the female spline shaft and the rubber material is large, and the initial rigidity when the male spline shaft is twisted is increased. As a result, there is a problem that a large torque is suddenly transmitted from the output shaft to the worm shaft with the start of energization of the electric motor, which gives the driver operating the steering wheel uncomfortable. More specifically, immediately after the operation of the steering wheel is started, the force required for the operation of the steering wheel suddenly decreases, which causes the driver to feel uncomfortable.

  Therefore, the present invention makes it possible to reduce the axial sliding resistance while suppressing an unpleasant noise called a rattling noise, and to provide an initial rigidity when the male member is twisted more than before. To provide a structure for a shaft, a male member, and a female member that suppresses suddenly large power from being transmitted to the shaft by reducing it, and that can reduce the uncomfortable feeling given to the driver. With the goal.

(1) The shaft structure according to the present invention is a shaft structure that is assembled to a shaft capable of transmitting power and is configured by inserting a male member into a female member so as to be slidable in the axial direction. A male member in which a plurality of male teeth and a plurality of male teeth bottoms are formed on the outer periphery; a plurality of female teeth and a plurality of female teeth bottoms are formed on the inner periphery; Between the female member into which the male member is inserted, and between the male member and the female member so as to adhere to the surface of the outer peripheral portion of the male member and cover the surface of the outer peripheral portion, and the teeth of the female tooth portion An initial state in which the male member is inserted into the female member, and a fiber member impregnated with rubber or resin, which is provided so as to contact the tip portion and the root portion of the female tooth portion in advance. In the fiber member and between the female tooth portion and the female tooth bottom portion of the inner peripheral portion of the female member A portion which faces the fiber member had a feature in that the tooth tip portion and root portion of the Mesuha portion of the Mesuha portion in which the fiber member is preliminarily contact, a gap surrounded by is formed To do.

According to the configuration of (1) above , between the male member and the female member, the surface of the outer peripheral portion of the male member is in close contact with and covers the surface of the outer peripheral portion, and the tooth tip portion of the female tooth portion and Since the fiber member impregnated with rubber or resin is provided so as to contact the root portion of the female tooth portion in advance , the male member while suppressing the rattling noise generated between the male member and the female member. And the sliding resistance in the axial direction between the female member and the female member can be reduced. Further, by improving the slidability, it is not necessary to supply the lubricating oil between the outer peripheral portion of the male member and the inner peripheral portion of the female member, and it is possible to save labor such as replenishment of the lubricating oil. Furthermore, in the initial state where the male member is inserted into the female member, the fiber member, a portion of the inner peripheral portion of the female member that faces the fiber member between the female tooth portion and the female tooth bottom portion, and the fiber A gap surrounded by the tip portion of the female tooth portion and the root portion of the female tooth portion with which the member abuts in advance can be formed. Thereby, when the male member is twisted in the circumferential direction in the initial state, the contact area between the fiber member and the inner peripheral portion of the female member can be gradually increased. As a result, the initial rigidity when the male member is twisted can be reduced as compared with the conventional one, and it is possible to suppress a large amount of power from being transmitted to the shaft. This can prevent the driver from feeling uncomfortable as in the past.

(2) In the shaft structure according to the present invention, a portion of the inner peripheral portion of the female member facing the fiber member between the female tooth portion and the female tooth bottom portion is a periphery of the male member. When the twisting in the direction is started in the initial state, the abutting portion that abuts against the fiber member, and the abutting portion and the fiber member abut against each other, and then pressed by the fiber member. And a pressing portion.

  According to the configuration of (2) above, when the twisting of the male member in the circumferential direction is started in the initial state, the fiber member comes into contact with the inner peripheral portion of the female member and the fiber member. The female member can be started to rotate in the circumferential direction while being gently deformed. In addition, after the contact portion and the fiber member are in contact, the female member can be rotated in the circumferential direction in earnest while the fiber member is deformed. Thereby, a contact area with the part which contacts a fiber member can be expanded more accurately. As a result, it is possible to further reduce the initial rigidity when the male member is twisted.

(3) The shaft structure of the present invention is a shaft structure that is assembled to a shaft capable of transmitting power and is configured by inserting a male member into a female member so as to be slidable in the axial direction. A male member in which a plurality of male teeth and a plurality of male teeth bottoms are formed on the outer periphery; a plurality of female teeth and a plurality of female teeth bottoms are formed on the inner periphery; Between the female member into which the male member is inserted, and between the male member and the female member, the surface of the inner peripheral portion of the female member is in close contact with the surface of the inner peripheral portion and the male tooth portion A fiber member impregnated with rubber or resin, which is provided so as to be in contact with the tooth tip portion and the root portion of the male tooth portion in advance , and the male member is inserted into the female member In an initial state, between the fiber member and the male tooth portion and the male tooth bottom portion of the outer peripheral portion of the male member. A portion which faces the fiber member had a feature in that the tooth tip portion and root portion of the Okha portion of the Okha portion in which the fiber member is preliminarily contact, a gap surrounded by is formed To do.

According to the configuration of (3) above , between the male member and the female member, the surface of the inner peripheral portion of the female member is in close contact with the surface of the inner peripheral portion and the tooth tip of the male tooth portion is covered. Since the fiber member impregnated with rubber or resin is provided so as to contact the base portion of the portion and the male tooth portion in advance , the male member while suppressing the rattling noise generated between the male member and the female member is provided. The sliding resistance in the axial direction between the mold member and the female mold member can be reduced. Further, by improving the slidability, it is not necessary to supply the lubricating oil between the outer peripheral portion of the male member and the inner peripheral portion of the female member, and it is possible to save labor such as replenishment of the lubricating oil. Further, in the initial state in which the male member is inserted into the female member, the fiber member, a portion of the outer peripheral portion of the male member facing the fiber member between the male tooth portion and the male tooth bottom portion, and the fiber member Is formed between the tooth tip portion of the male tooth portion and the root portion of the male tooth portion, which are in contact with each other in advance . Thereby, when the male member is twisted in the circumferential direction in the initial state, the contact area with the portion in contact with the fiber member can be gradually increased. As a result, the initial rigidity when the male member is twisted can be reduced as compared with the conventional one, and it is possible to suppress a large amount of power from being transmitted to the shaft. This can prevent the driver from feeling uncomfortable as in the past.

(4) In the shaft structure according to (3), a portion of the outer peripheral portion of the male member that faces the fiber member between the male tooth portion and the male tooth bottom portion is the male member. A contact portion capable of starting rotation of the female member in the circumferential direction while deforming the fiber member by contacting the fiber member when the circumferential twisting is started in the initial state. A pressing portion capable of rotating the female member in the circumferential direction while deforming the fiber member by pressing the opposing fiber member after the contact portion and the fiber member are in contact with each other; It is preferable.

  According to the configuration of (4) above, when the twisting of the male member in the circumferential direction is started in the initial state, the fiber is formed between the male tooth portion and the male tooth bottom portion of the outer peripheral portion of the male member. When the part facing the member comes into contact with the fiber member, rotation of the female member in the circumferential direction can be started while gently deforming the facing fiber member. In addition, by pressing the opposing fiber member after the contact portion and the fiber member are in contact, the female member can be rotated in the circumferential direction in earnest while the fiber member is deformed. . Thereby, a contact area with the part which contacts a fiber member can be expanded more accurately. As a result, it is possible to further reduce the initial rigidity when the male member is twisted.

(5) The male member of the present invention is assembled to a shaft capable of transmitting power, and is slidably inserted into a female member in which a plurality of female teeth and a plurality of female teeth bottoms are formed on the inner periphery. A plurality of male teeth formed on the outer peripheral portion, a plurality of male tooth bottoms formed on the outer peripheral portion, and the plurality of male teeth. In close contact with the surface of the outer peripheral portion of the portion and the plurality of male tooth bottom portions and covering the surface of the outer peripheral portion, and when inserted into the female member, between the male member and the female member A fiber member impregnated with rubber or resin, which is provided in advance so as to abut on the tip portion of the female tooth portion and the root portion of the female tooth portion, and is inserted into the female mold member In the initial state, the female tooth portion and the female tooth bottom portion of the inner periphery of the fiber member and the female member A portion which faces the fibrous member in between, said a tooth tip portion and root portion of the Mesuha portion of the Mesuha section fiber member is preliminarily contact, surrounded by a gap is formed Features.

According to the configuration of (5) above, the outer surface of the male member is in close contact with and covers the outer peripheral surface, and when inserted into the female member, the male member and the female member Since a fiber member impregnated with rubber or resin is provided so as to be in contact with the tooth tip portion of the female tooth portion and the root portion of the female tooth portion in between, it is generated between the male member and the female member. The axial sliding resistance between the male member and the female member can be reduced while suppressing rattling noise. Further, by improving the slidability, it is not necessary to supply the lubricating oil between the outer peripheral portion of the male member and the inner peripheral portion of the female member, and it is possible to save labor such as replenishment of the lubricating oil. Further, in the initial state of being inserted into the female member, the fiber member, the portion of the inner peripheral portion of the female member that faces the fiber member between the female tooth portion and the female tooth bottom portion, and the fiber member are applied in advance. A gap surrounded by the tip portion of the female tooth portion in contact with the root portion of the female tooth portion is formed. Thereby, when the male member is twisted in the circumferential direction in the initial state, the contact area with the portion in contact with the fiber member can be gradually increased. As a result, the initial rigidity when the male member is twisted can be reduced as compared with the conventional one, and it is possible to suppress a large amount of power from being transmitted to the shaft. This can prevent the driver from feeling uncomfortable as in the past.

(6) In the male member of (5), a portion of the inner peripheral portion of the female member that faces the fiber member between the female tooth portion and the female tooth bottom portion is the male member. When the twisting in the circumferential direction is started in the initial state, the abutting portion that abuts against the facing fiber member, and the abutting portion and the fiber member abut against each other, the facing It is preferable that it is used for the structure for shafts inserted and inserted in the female-type member which has a press part pressed by the fiber member.

  According to the configuration of (6) above, when the twisting of the male member in the circumferential direction is started in the initial state, between the female tooth portion and the female tooth bottom portion of the inner peripheral portion of the female member. When the part facing the fiber member comes into contact with the fiber member, the rotation of the female member in the circumferential direction can be started while the fiber member is gently deformed. In addition, after the contact portion and the fiber member are in contact, the female member can be rotated in the circumferential direction in earnest while the fiber member is deformed. Thereby, the contact area of a fiber member and a contact part can be expanded more accurately. As a result, it is possible to further reduce the initial rigidity when the male member is twisted.

(7) The female member of the present invention is assembled to a shaft capable of transmitting power, and a male member having a plurality of male teeth and a plurality of male teeth bottoms formed on the outer periphery is slidably inserted. A female member used for a shaft structure configured as described above, wherein a plurality of female tooth portions formed on an inner peripheral portion, a plurality of female tooth bottom portions formed on an inner peripheral portion, and the plurality of the plurality of female tooth portions The male member and the female member when the male member is inserted while closely contacting the surface of the inner peripheral portion of the female tooth portion and the plurality of female tooth bottom portions and covering the surface of the inner peripheral portion. A fiber member impregnated with rubber or resin, which is provided in advance so as to abut on the tooth tip part of the male tooth part and the root part of the male tooth part. In the initial state in which the male member and the male tooth are out of the outer periphery of the fiber member and the male member A portion which faces the fiber member, a tooth tip portion and root portion of the Okha portion of the Okha portion in which the fiber member is preliminarily in contact, a gap surrounded by the formed between the parts It is characterized by that.

According to the above configuration (7), covers the surface of the inner peripheral portion in close contact with the surface of the inner peripheral portion of the female member, when the male member is inserted, the male member and the female member Since a fiber member impregnated with rubber or resin is provided so as to contact the tip portion of the male tooth portion and the root portion of the male tooth portion in advance , between the female member and the male member The axial sliding resistance between the female member and the male member can be reduced while suppressing the generated rattling noise. Further, by improving the slidability, it is not necessary to supply the lubricating oil between the inner peripheral portion of the female member and the outer peripheral portion of the male member, and it is possible to save troubles such as replenishment of the lubricating oil. Further, in the initial state in which the male member is inserted, the fiber member and the portion facing the fiber member between the male tooth portion and the male tooth bottom portion of the outer periphery of the male member are in contact with the fiber member in advance. A gap surrounded by the tooth tip portion of the male tooth portion and the root portion of the male tooth portion is formed. Thereby, when the male member is twisted in the circumferential direction in the initial state, the contact area between the fiber member and the contact portion can be gradually increased. As a result, the initial rigidity when the male member is twisted can be reduced as compared with the conventional one, and it is possible to suppress a large amount of power from being transmitted to the shaft. This can prevent the driver from feeling uncomfortable as in the past.

(8) In the female member of (7), a portion of the outer peripheral portion of the male member that faces the fiber member between the male tooth portion and the male tooth bottom portion is a periphery of the male member. A contact portion capable of starting rotation of the female member in the circumferential direction while deforming the fiber member by contacting the fiber member when starting twisting in the direction in the initial state; A male mold having a pressing section capable of rotating the female mold member in the circumferential direction while deforming the fiber member by pressing the opposing fiber member after the abutting section and the fiber member abut. It is preferably used for a shaft structure configured by inserting a member.

  According to the configuration of (8) above, when the male member is started to be twisted in the circumferential direction in the initial state, the fiber is formed between the male tooth portion and the male tooth bottom portion of the outer peripheral portion of the male member. When the member facing the member abuts on the fiber member, rotation of the female member in the circumferential direction of the male member can be started while gently deforming the facing fiber member. In addition, after the contact portion and the fiber member are in contact with each other, the female member can be rotated in the circumferential direction in earnest while the fiber member is deformed. Thereby, the contact area of a fiber member and a contact part can be expanded more accurately. As a result, it is possible to further reduce the initial rigidity when the male member is twisted.

It is an example of the schematic diagram which shows schematic structure of the electric power steering apparatus to which the structure for shafts concerning the 1st Embodiment of this invention is applied. (A) It is an example of the perspective view of the structure for shafts concerning the 1st Embodiment of this invention. (B) It is the figure which expanded the arrow cross section of the AA line shown to Fig.2 (a). FIG. 3 is an enlarged view of a portion surrounded by a thick line in FIG. It is a disassembled perspective view of the principal part of the structure for shafts concerning a 1st embodiment of the present invention, (a) is an example of a male type member, (b) is an example of a female type member, and (c) is male. It is an example of the fiber member provided in the outer peripheral part of a type | mold member. It is an example of the perspective view of the male type | mold member which concerns on the 1st Embodiment of this invention, Comprising: It is an example by which the fiber member was affixed on the outer peripheral part of the male type | mold member using the adhesive agent. It is a schematic diagram which shows schematic structure of the servo testing machine used for the torsional rigidity test. It is a result of a torsional rigidity test, and shows each torque characteristic of the structure for shaft measured using a servo tester. It is an example of the schematic diagram which shows schematic structure of the electric power steering apparatus to which the structure for shafts concerning the 2nd Embodiment of this invention is applied. (A) It is an example of the perspective view of the structure for shafts concerning the 2nd Embodiment of this invention. (B) It is the figure which expanded the arrow cross section of the BB line shown to Fig.9 (a). FIG. 10 is an enlarged view of a portion surrounded by a thick line in FIG. It is a disassembled perspective view of the principal part of the structure for shafts concerning the 2nd embodiment of the present invention, (a) is an example of a male type member, (b) is an example of a female type member, and (c) is female. It is an example of the fiber member provided in the inner peripheral part of a type | mold member. It is an example of the perspective view of the female-type member which concerns on the 2nd Embodiment of this invention, Comprising: It is an example by which the fiber member was affixed on the inner peripheral part of the female-type member using the adhesive agent.

[First Embodiment]
1 to 7, the shaft structure (spline) according to the first embodiment of the present invention, the male member (male spline shaft) and the female member constituting the shaft structure. (Female spline shaft) will be described.

(Overall configuration of electric power steering device)
Here, the configuration of each part will be described in conjunction with the operation of the electric power steering apparatus. As shown in FIG. 1, an electric power steering device (EPS) 1 includes a steering shaft (shaft) 3 connected to a steering wheel 2 as a steering member, a pinion gear 4 provided at the tip of the steering shaft 3, and A rack shaft 5 serving as a steering shaft has a rack gear 5 that meshes with the pinion gear 4 and extends in the left-right direction of the vehicle.

  Tie rods 7 are coupled to both ends of the rack shaft 6, and each tie rod 7 is connected to a corresponding wheel 8 via a corresponding knuckle arm (not shown). When the steering wheel 2 is operated and the steering shaft 3 is rotated, this rotation is converted into a linear motion of the rack shaft 6 along the left-right direction of the vehicle by the pinion gear 4 and the rack gear 5. Thereby, steering of the wheel 8 is achieved.

  The steering shaft 3 is divided into an input shaft 9 connected to the steering wheel 2 and an output shaft 10 connected to the pinion gear 4. These input and output shafts 9, 10 are mutually connected on the same axis via a torsion bar 11. It is connected. A torque sensor 12 is provided for detecting a steering torque based on the relative rotational displacement between the input and output shafts 9 and 10 via the torsion bar 11, and the torque detection result of the torque sensor 12 is given to the control unit 13. . The control unit 13 controls the voltage applied to the steering assist electric motor 15 via the driver 14 based on the torque detection result, the vehicle speed detection result, and the like. Then, the rotation of the rotating shaft (not shown) of the electric motor 15 is decelerated via the speed reduction mechanism 17. The output rotation of the speed reduction mechanism 17 is converted into the axial movement of the rack shaft 6 via the conversion mechanism 18 to assist the steering. The electric power steering apparatus 1 is a so-called rack assist type.

(Structure of shaft structure)
The shaft structure 20 according to the present embodiment is applied to the steering shaft 3 described above, for example. Hereinafter, the steering shaft 3 may be simply abbreviated as the shaft 3.

  A shaft structure 20 according to the present invention is assembled to a shaft 3 capable of transmitting power, and is configured by inserting a male member and a female member capable of transmitting the power so as to be slidable in the axial direction. As shown in FIG. 2, a metal male member 21, a metal female member 22, and a surface impregnated with rubber or the like so as to cover the surface of the outer peripheral portion 21c of the male member 21 are provided. The fiber member 23 is provided.

  As shown in FIG. 4A, the male member 21 has a substantially cylindrical base shaft portion 21a and a convex portion 21b that protrudes from one end of the base shaft portion 21a. The outer peripheral portion 21c of the convex portion 21b is formed between each male tooth portion 21d and, for example, six male tooth portions 21d adjacent to each other with a predetermined gap along the circumferential direction of the convex portion 21b. For example, six male tooth bottom portions 21e are formed.

  As shown in FIG. 4B, the female member 22 is formed in a substantially cylindrical shape, and the male member 21 in which the fiber member 23 (see FIG. 4C) is covered by the outer peripheral portion 21c is inserted. It has a possible inner periphery 22a. On the inner peripheral portion 22a of the female member 22, the same number (six in this embodiment) of female teeth 22b as the male teeth 21d formed on the convex portion 21b of the male member 21 are female members. 22 in a circumferential direction with a predetermined gap. Furthermore, the same number (six in this embodiment) of female tooth bottom portions 22c as the male tooth bottom portions 21e are formed on the inner peripheral portion 22a of the female member 22 between the adjacent female tooth portions 22b. The female tooth bottom portion 22c is formed so that its axial cross section is substantially U-shaped.

  The fiber member 23 can be formed of aramid fiber, nylon, urethane, cotton, silk, hemp, acetate, rayon, fiber containing fluorine, polyester, and the like, and is impregnated with rubber or resin. The shape of the fiber may be, for example, a short fiber shape or a long fiber shape, or may be a sheet-like cloth.

  By impregnating the fibers with rubber or resin, the rubber material or the resin material enters between the fibers, and the fibers can be bonded together to function as a member (sheet body) like the fiber member 23. Become. Further, when the fiber is impregnated with rubber or the like, wear due to rubbing between the fibers is reduced, and further, the wear of the surface of the fiber member 23 generated between the fiber member 23 and the female mold member 22 is increased. It becomes possible to plan.

  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. In addition to these, in order to improve the lubricity of the fiber member 23, a solid lubricant such as graphite, silicon oil, fluorine powder, or molybdenum disulfide may be included in the rubber. 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-described 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. . In actual use, 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 the fabric include a nonwoven fabric in which fibers are entangled irregularly, a woven fabric formed regularly, and a knitted fabric (knit). Since these cloths are in the form of a sheet compared to those composed only of fibers (short fibers or long fibers), they can be easily impregnated with rubber or the like (easy to handle), and a shaft structure described later. It has the feature that it is easy to adhere to the surface of the film. For the weaving method, plain weave, satin weave, twill weave, or the like is used.

  In addition, the cloth preferably has a certain degree of elasticity. When the cloth is molded into a shape along the shape of the male tooth portion 21d and the male tooth bottom portion 21e, or when bonded to the surface of the outer peripheral portion 21c of the male mold member 21, the surface has an uneven shape. Since the cloth has stretchability, the cloth surface easily conforms to the uneven shape, and there is an advantage that the surface of the finished fiber member 23 is not easily wrinkled and the surface is finished uniformly. As a result, the insertion of the male member 21 into the female member 22 can be made smooth. Further, sliding resistance generated between the female member 22 and the fiber member 23 can be reduced. In particular, by producing the fiber member 23 so that the direction of the stretchability of the cloth matches at least the circumferential direction of the cylindrical fiber member 23, the generation of wrinkles and the like can be further suppressed. .

  As shown in FIG. 4C, the impregnated fiber member 23 includes an inner peripheral portion 23a having substantially the same shape as the outer peripheral portion 21c of the male mold member 21 (see FIG. 4A), and the female mold member 22. And an outer peripheral portion 23b that can be inserted into the inner peripheral portion 22a (see FIG. 4B). In the present embodiment, as shown in FIG. 5, the impregnated fiber member 23 is bonded to the outer peripheral portion 21 c of the male member 21. Adhesives used here are acrylic resin adhesives, olefin adhesives, urethane resin adhesives, ethylene-vinyl acetate resin adhesives, epoxy resin adhesives, vinyl chloride resin adhesives, chloroprene rubber Adhesives, cyanoacrylate adhesives, silicone adhesives, styrene-butadiene rubber adhesives, nitrile rubber adhesives, hot melt adhesives, phenol resin adhesives, melamine resin adhesives, urea resin adhesives There are adhesives, resorcinol adhesives, etc., a method of curing and bonding by applying and cooling the adhesive after it has been heated and melted, and curing by heating the adhesive. There is a method of bonding.

  In the present embodiment, the impregnated fiber member 23 is covered over the entire circumference of the outer peripheral portion 21c of the male member 21, and, for example, as shown in FIG. 2A, the male member to which the fiber member 23 is bonded is attached. The mold member 21 has a tip portion protruding in the axial direction from the end portion of the female mold member 22. The distal end portion of the male member 21 is appropriately processed according to the usage state of the shaft structure 20.

  FIG.2 (b) is the figure which expanded the arrow cross section of the AA line shown to Fig.2 (a). As shown in FIG. 2B, the shaft structure 20 of the present embodiment is obtained when the male member 21 in which the impregnated fiber member 23 is bonded to the outer peripheral portion 21 c is inserted into the female member 22. A closed curved gap S1 surrounded by the outer peripheral portion 23b of the fiber member 23 and the contact portion P1 formed on the inner peripheral portion 22a of the female mold member 22 is formed. The contact portion P <b> 1 is a portion that can contact the outer peripheral portion 23 b of the opposing fiber member 23.

  FIG. 3 is an enlarged view of a portion surrounded by a thick line in FIG. As shown in FIG. 3, the contact portion P1 (curve P1 in FIG. 3) is a line segment connecting the points A1 and A2. Point A1 is a point where the outer peripheral portion 23b of the fiber member 23 and the root portion of the female tooth portion 22b are in contact with each other. Point A2 is a point where the outer peripheral portion 23b of the fiber member 23 contacts the tooth tip portion of the female tooth portion 22b. In the contact portion P1 (curve P1), points A3 and A4 exist from the point A1 toward the point A2. The positions of the points A3 and A4 can be changed as appropriate according to the usage state of the shaft structure 20. The contact portion P1 (curve P1) includes a contact portion P11 and a pressing portion P12. In the present embodiment, the contact portion P11 is configured by a line segment connecting the points A1 and A3. The contact portion P11 is in an initial state (FIG. 2B in the first embodiment) in which the male member 21 is twisted in the circumferential direction (the right direction of the arrow shown in white in FIG. 2B). This is a portion that comes into contact with the outer peripheral portion 23b of the opposing fiber member 23 when starting in the state shown in FIG. By contacting the contact portion P11 with the outer peripheral portion 23b of the fiber member 23, the fiber member 23 is deformed, and the female member 22 is moved in the circumferential direction (indicated by the white arrow in FIG. 2B). Direction). Further, the pressing portion P12 is configured by a line segment connecting the points A3 and A4. The pressing portion P12 is formed after the contact portion P11 and the fiber member 23 come into contact with each other by being twisted in the circumferential direction of the male member 21 (the right direction of the arrow shown in white in FIG. 2B). It is a site | part pressed by the outer peripheral part 23b of the fiber member 23 which opposes. Further, when the male member 21 is twisted in the circumferential direction (right arrow direction indicated by white in FIG. 2B), the pressing portion P12 is pressed against the outer peripheral portion 23b of the fiber member 23. Thus, while the fiber member 23 is deformed, the female member 22 can be rotated in the circumferential direction (right arrow direction indicated by white in FIG. 2B).

  The gap S <b> 1 is formed over the entire length along the axial direction of the female member 22. Thereby, when the male member 21 is twisted in the circumferential direction (right arrow direction indicated by white in FIG. 2B), the cross-sectional shape of the fiber member 23 is deformed so that the gap S1 is absorbed, The contact area with the fiber member 23 in the contact part P11 and the pressing part P12 is increased. Thereafter, the female member 22 rotates following the male member 21, and the pinion gear (see FIG. 1) rotates.

  Here, as an example of the manufacturing method of the shaft structure 20, a male member 21 and a female member 22 each having a shape shown in FIGS. 4A and 4B from a metal material (not shown) are used. Examples of the manufacturing method include a step of cutting, a step of impregnating the fiber member 23 with rubber or the like, and a step of providing the fiber member 23 impregnated on the outer peripheral portion 21c of the male member 21.

  Moreover, as a manufacturing method of the fiber member 23, the following manufacturing methods can be selected suitably. For example, when the fiber member 23 of FIG. 4C is molded, first, an inner mold and an outer mold that can mold the inner peripheral portion 23a and the outer peripheral portion 23b are prepared. Naturally, the outer peripheral surface of the inner mold and the inner peripheral surface of the outer mold are provided with uneven shapes along the inner peripheral portion 23a and the outer peripheral portion 23b, respectively. And after filling the fiber (short fiber or long fiber, or cloth (sheet shape)) impregnated with rubber or resin between these two molds, pressure and pressure are applied to the fibers filled from the inner mold and the outer mold. A temperature is applied, and then the fiber is removed from the mold to obtain the fiber member 23 in which the inner peripheral portion 23a and the outer peripheral portion 23b are molded.

  Further, as a manufacturing method of the fiber member 23, a cloth to be filled between the inner mold and the outer mold is finished in a cylindrical shape along the outer shape of the inner mold, and the cloth is in conformity with the outer shape of the inner mold. There is also a method of molding the fiber member 23 by covering the inner mold and then applying pressure and temperature in the same manner as described above. In this case, since the cloth has elasticity, the fiber member 23 can be further molded along the concave and convex shapes of the inner mold and the outer mold. As a result, a molded product having a uniform surface can be manufactured without causing wrinkles or the like in the inner peripheral portion 23a or the outer peripheral portion 23b of the fiber member 23. By providing the fiber member 23 having a uniform surface on the outer peripheral portion 21c of the male member 21, the sliding resistance in the axial direction can be further reduced. In addition, generation | occurrence | production of said wrinkles etc. can be suppressed further by finishing a cloth into a cylindrical shape so that the direction which shows the elasticity of a cloth may correspond with the circumferential direction of the cylindrical fiber member 23 at least.

  As shown in FIG. 5, the manufacturing method in the case where the impregnated fiber member 23 is bonded to the outer peripheral portion 21 c of the male mold member 21 is the same as that in which the inner mold of the above manufacturing method is used as the male mold member 21. Further, after applying an adhesive to the metal surface of the male member 21, fibers (short fibers or long fibers, or cloth (sheets) impregnated with rubber or resin between the male member 21 and the outer mold are used. 5), pressure and temperature are applied from the outer mold, and then the outer mold is removed to obtain the member of FIG. 5 in which the fiber member 23 is bonded to the outer peripheral portion 21c of the male mold member 21. Further, similarly to the above manufacturing method, the cloth is finished into a cylindrical shape that follows the outer shape of the male member 21, and the cloth is covered with the outer diameter of the male member 21, and pressure is applied. Five members may be obtained. In this case, the cloth has elasticity so that the surface of the fiber member 23 adhered to the outer peripheral portion 21c of the male member 21 is less likely to be wrinkled, and the male member 21 having a uniform surface is manufactured. Therefore, the axial sliding resistance of the male member 21 and the female member 22 of the shaft structure 20 can be further reduced. In addition, as described above, the generation of the wrinkles and the like can be further suppressed by finishing the cloth in a cylindrical shape so that the direction in which the cloth exhibits elasticity matches at least the circumferential direction of the male member 21. is there.

  Next, the present invention will be described specifically by way of examples. Here, the result of examining the usefulness of the shaft structure 20 (see FIG. 2) according to the present embodiment by a torsional rigidity test will be described. In addition, this invention is not limited to a present Example. More specifically, the inventor described that when the male member and the female member are in contact with each other without providing the shaft structure 20 (see FIG. 2) and the fiber member 23 of the present embodiment, the metal surface A torsional rigidity test was performed by comparison with a conventional shaft structure that would be in contact with each other.

  FIG. 6 shows a torsional rigidity tester used for the torsional rigidity test. In addition, although the spline in FIG. 6 is actually the same as the shaft structure 20 (see FIG. 2) according to the present embodiment, it is shown in a schematic diagram for convenience. Therefore, illustration of the fiber member 23 is omitted. In FIG. 6, one end of the female member 22 into which one end side of the male member 21 is inserted is fixed to a plate-like fixing base. The other end of the male member 21 is supported in a state where it can be twisted around the surface of one end of a substantially rectangular parallelepiped arm. A load point to which a load can be applied is provided on the side surface on the other end side of the arm. When a predetermined load is applied to this load point, a predetermined torque is applied to the male mold member 21, and the male mold member 21 is twisted in the circumferential direction around the central axis. At that time, the conditions of the torsional rigidity test are given as follows. As a torsional rigidity tester, a servo tester was used, and the test was performed with an excitation frequency [Hz] of 0.01 [Hz] and a load [N] of ± 400 [N]. In this embodiment, the distance D [mm] is designed to be 20 [mm]. The distance D [mm] here is a distance between the straight lines L1 and L2. The straight line L1 is a plane that is substantially orthogonal to the central axis of the male member 21, exists on a virtual plane that includes the load direction to which the load is applied, and is substantially orthogonal to the central axis of the male member 21. And a line parallel to the load direction. The straight line L2 is a line that matches the load direction at the load point. In addition, the torsional rigidity test was done also on the conventional shaft structure under the same test conditions.

  FIG. 7 shows the results of the torsional rigidity test, wherein (a) shows the torque characteristics of the shaft structure 20 measured using a torsional rigidity tester, and (b) shows the same servo. Each torque characteristic of the conventional structure for shafts measured using a testing machine is shown. Here, the horizontal axis of FIGS. 7A and 7B represents the torque [N · m applied to each male member of the shaft structure 20 of the present embodiment and the conventional metal shaft structure. The vertical axis represents the twist angle [deg] when each male member is twisted. The shaft structure 20 according to the present embodiment has the shaft structure 20 according to the first embodiment shown in FIG. 2, that is, the fiber member 23 impregnated with rubber or resin bonded to the outer peripheral portion 21c. The male member 21 is inserted into the female member 22. In addition, the conventional metal structure for a shaft of a single metal is such that the metal surfaces are in contact with each other, that is, there is no elastic member such as a fiber member between the male member and the female member, The male member whose outer peripheral part is a metal surface is inserted into the female member whose inner peripheral part is a metal surface.

  7A, in the shaft structure 20 according to the present embodiment in which the fiber member 23 is provided so as to cover the surface of the outer peripheral portion 21c of the male member 21, the male member 21 is disposed in the circumferential direction (FIG. 2). (B) As the contact area between the fiber member 23 and the contact portion P1 (see FIG. 3) increases with twisting in the direction indicated by the white arrows in white), the points A1 and A3 are As the connected curve P11 (see FIG. 3) and the curve P12 (see FIG. 3) connecting the points A3 and A4 sequentially contact the outer peripheral portion 23b (see FIG. 3) of the opposing fiber member 23, the male type When the member 21 is twisted, the initial rigidity gradually increases, and the line segment connecting the points A4 and A2 (see FIG. 3) comes into contact with the outer peripheral portion 23b (see FIG. 3) of the opposing fiber member 23, The rigidity increases in earnest from the moment when the gap S1 (see FIG. 3) disappears.

  On the other hand, as shown in FIG. 7B, in the conventional shaft structure made of a single metal in which the metal surfaces are in contact with each other, the initial rigidity when the male member is twisted is the shaft structure according to the present embodiment. It rises more rapidly than the body 20, and does not rise gradually little like this embodiment. In FIG. 7B, the reason why the twist angle [deg] is small near 0 [deg] is due to the rattling of the conventional metal single shaft structure.

(Characteristics of the shaft structure according to the first embodiment of the present invention)
According to the above configuration, the outer peripheral portion 21 c of the male mold member 21 is provided with the fiber member 23 impregnated with rubber or the like, so that the outer peripheral section 21 c of the male mold member 21 and the inner peripheral section 22 a of the female mold member 22 are formed. To simultaneously solve both problems that are in a trade-off relationship, such as suppression of unpleasant noise such as rattling noise generated from the gap and reduction of axial sliding resistance between the male member 21 and the female member 22 Can do. Further, since the axial slidability of the male member 21 and the female member 22 is improved, the lubricating oil is applied between the outer peripheral portion 21c of the male member 21 and the inner peripheral portion 22a of the female member 22. There is no need to supply the lubricant, and it is possible to save troubles such as lubrication. Furthermore, by impregnating the fiber member 23 with rubber or resin, it is possible to improve the wearability of the surface of the fiber member 23 that occurs between the fiber member 23 and the inner peripheral portion 22a of the female member 22.

  Further, as shown in the above configuration, in the initial state in which the male member 21 is inserted into the female member 22, the gap surrounded by the fiber member 23 and the contact portion P1 in the inner peripheral portion 22a of the female member 22 S1 can be formed. As a result, when the male member 21 is twisted in the circumferential direction (right arrow direction indicated by white in FIG. 2B) in the initial state, the contact area between the fiber member 23 and the contact portion P1 is gradually increased. Can be expanded. As a result, the initial rigidity when the male member 21 is twisted can be reduced as compared with the conventional case, and abrupt transmission of large power to the shaft 3 can be suppressed. As a result, it is possible to prevent the driver from feeling uncomfortable as in the past (a feeling of strangeness in which the force required to operate the steering wheel 2 suddenly decreases immediately after the operation of the steering wheel 2 is started).

  Further, as shown in the above configuration, when the twisting of the male member 21 in the initial state in the circumferential direction (right arrow direction indicated by white in FIG. 2B) is started, the contact portion P1 is The contact portion P11 is in contact with a portion of the outer peripheral portion 23b of the fiber member 23 that faces the contact portion P11, so that the fiber member 23 that faces the contact portion P11 is gently deformed, and the circumferential direction (FIG. The rotation of the female member 22 in the direction indicated by the white arrow in 2 (b) can be started. In addition, the pressing portion P12 of the contact portion P1 is formed on the outer peripheral portion 23b of the fiber member 23 after the contact portion P11 and the outer peripheral portion 23b of the fiber member 23 are in contact with the portion facing the contact portion P11. By pressing the portion facing the pressing portion P12, the fiber member 23 facing the pressing portion P12 is deformed, and the female member 22 is moved in the circumferential direction (indicated by the white arrow in FIG. 2B). ) Can be fully rotated. Thereby, the contact area of the fiber member 23 and the contact part P1 can be expanded more accurately. As a result, the initial rigidity when the male member 21 is twisted can be further reduced.

  The initial stiffness in the present embodiment is a line connecting points A1 and A2 when the male member 21 is twisted in the circumferential direction (right arrow direction indicated by white in FIG. 2B). The minute (curve P1 in FIG. 3) may mean the rigidity when contacting the outer peripheral portion 23b (see FIG. 3) of the opposing fiber member 23 until the moment when the gap S1 (see FIG. 3) disappears, The line segment connecting the points A1, A3, A4 (curves P11, P12 in FIG. 3) means the rigidity until the moment when it contacts the outer peripheral portion 23b (see FIG. 3) of the opposing fiber member 23. May be.

  Further, as seen in FIG. 2A, in the shaft structure 20 according to the present embodiment in which the fiber member 23 is provided so as to cover the surface of the outer peripheral portion 21c of the male member 21, the male member 21 is surrounded. As the contact area between the fiber member 23 and the contact portion P1 (see FIG. 3) increases with twisting in the direction (right arrow direction indicated by white in FIG. 2B), As the curve P11 (refer to FIG. 3) connecting A1 and A3 and the curve P12 (refer to FIG. 3) connecting points A3 and A4 sequentially contact with the outer peripheral portion 23b (refer to FIG. 3) of the opposing fiber member 23. When the male member 21 is twisted, the initial rigidity gradually increases, and the line segment connecting the points A4 and A2 (see FIG. 3) faces the outer peripheral portion 23b (see FIG. 3) of the fiber member 23 facing each other. From the moment when the contact S1 (see FIG. 3) disappears, the rigidity increases in earnest. Go. As a result, the initial rigidity can be gradually increased more gradually than the conventional shaft structure having a structure in which the fiber member 23 is made of metal. That is, the contact area with the fiber member 23 gradually increases from A1 toward A3, and then the contact area with the fiber member 23 gradually increases from A3 toward A4. By gradually bringing the constituent parts of the part P1 into contact with the outer peripheral part 23b of the fiber member 23 in order, the contact area between the fiber member 23 and the contact part P1 can be expanded with higher accuracy, and gradually and gradually. The initial stiffness can be increased.

[Second Embodiment]
Next, referring to FIGS. 8 to 12, a shaft structure (spline) according to the second embodiment of the present invention, a male member (male spline shaft) and a female mold constituting the shaft structure. The member (female spline shaft) will be described. The parts 1 to 15, 17, and 18 in the first embodiment and the parts 101 to 115, 117, and 118 in the present embodiment are the same in order, and thus detailed description thereof is omitted. is there.

(Overall configuration of electric power steering device)
As shown in FIG. 8, an electric power steering device (EPS) 101 includes a steering shaft (shaft) 103 connected to a steering wheel 102 as a steering member, a pinion gear 104 provided at the tip of the steering shaft 103, and A rack shaft 105 that has a rack gear 105 that meshes with the pinion gear 104 and extends in the left-right direction of the vehicle is provided.

(Structure of shaft structure)
The shaft structure according to the present embodiment is applied to the steering shaft 103 described above, for example. Hereinafter, the steering shaft 103 may be simply abbreviated as the shaft 103.

  A shaft structure 120 according to the present invention is assembled to a shaft 103 capable of transmitting power, and is configured by inserting a male member and a female member capable of transmitting the power so as to be slidable in the axial direction. As shown in FIG. 9, it is impregnated with a metal male member 121, a metal female member 122, and rubber or the like so as to cover the surface of the inner peripheral portion 122a of the female member 122. The fiber member 123 is provided.

  As shown in FIG. 11A, the male member 121 includes a substantially cylindrical base shaft portion 121a and a convex portion 121b that protrudes from one end of the base shaft portion 121a. For example, six male tooth parts 121d adjacent to each other with a predetermined gap along the circumferential direction of the convex part 121b and the male tooth parts 121d are formed on the outer peripheral part 121c of the convex part 121b. For example, six male tooth bottom portions 121e are formed. The outer peripheral part 121c of the convex part 121b is configured to be insertable into the female member 122 in which the inner peripheral part 122a is covered with the fiber member 123 (see FIG. 11C).

  As shown in FIG. 11B, the female member 122 is formed in a substantially cylindrical shape. On the inner peripheral portion 122a of the female member 122, the same number (six in this embodiment) of female teeth 122b as the male teeth 121d formed on the convex portion 121b of the male member 121 are female members. It is formed with a predetermined gap in the circumferential direction 122. Furthermore, the same number (six in this embodiment) of female tooth bottom portions 122c as the male tooth bottom portions 121e are formed between the adjacent female tooth portions 122b on the inner peripheral portion 122a of the female mold member 122. The female tooth bottom portion 122c is formed so that its axial cross section is substantially U-shaped.

  The fiber member 123 can be formed using the same material as the fiber member 23 of the first embodiment, and is impregnated with rubber or resin. The shape of the fiber may be, for example, a short fiber shape or a long fiber shape, or may be a sheet-like cloth.

  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 a member (sheet body) like the fiber member 123. Become. Further, by impregnating the fiber with rubber or the like, wear due to rubbing between the fibers is reduced, and further, the wear of the surface of the fiber member 123 generated between the fiber member 123 and the male mold member 121 is increased. It becomes possible to plan.

  In addition, the rubber | gum should just be what can impregnate a fiber, and what was illustrated in 1st Embodiment can be used for it. These rubbers can be used alone, as in the first embodiment, or can be used by blending a plurality of types of rubbers. In addition, an appropriate amount of the compounding agent exemplified in the first embodiment can be blended in the rubber. In addition to these, in order to improve the lubricity of the fiber member 123, a solid lubricant such as graphite, silicon oil, fluorine powder, or molybdenum disulfide may be included in the rubber. 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.

  In the above-described impregnation treatment of fibers with rubber or resin, the rubber or resin is dissolved with a solvent or the like to form a liquid as in the first embodiment, and then a predetermined fiber (short fiber, long fiber or cloth) is dipped. The method of processing is preferably used. In actual use, 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.

  Further, as in the first embodiment, the cloth preferably has a certain degree of stretchability. When the cloth is molded into a shape that conforms to the shape of the female tooth portion 122b and the female tooth bottom portion 122c, or when the cloth is bonded to the inner peripheral portion 122a surface of the female mold member 122, the surface is uneven. Since the cloth is stretchable, there is an advantage that the surface of the cloth easily conforms to the uneven shape, the surface of the finished fiber member 123 does not easily wrinkle, and the surface is finished uniformly. As a result, the male member 121 can be smoothly inserted into the female member 122. Furthermore, the sliding resistance generated between the male member 121 and the fiber member 123 can be reduced. In particular, by producing the fiber member 123 so that the direction of the stretchability of the cloth coincides with at least the circumferential direction of the cylindrical fiber member 123, the generation of wrinkles and the like can be further suppressed. .

  As shown in FIG. 11C, the impregnated fiber member 123 includes an inner peripheral portion 123a into which the outer peripheral portion 121c (see FIG. 11A) of the male member 121 can be inserted, and the female member 122. It has an inner peripheral part 122a (see FIG. 11B) and an outer peripheral part 123b having substantially the same shape. In the present embodiment, as shown in FIG. 12, the impregnated fiber member 123 is bonded to the inner peripheral portion 122a of the female member 122. As the adhesive used here, the adhesive exemplified in the first embodiment can be used.

  In the present embodiment, the impregnated fiber member 123 is covered over the entire circumference of the inner peripheral portion 122a of the female member 122. For example, as shown in FIG. It has a tip portion protruding in the axial direction from the end of the mold member 122. The distal end portion of the male member 121 is appropriately processed according to the use state of the shaft structure 120.

  FIG.9 (b) is the figure which expanded the arrow cross section of the BB line shown to Fig.9 (a). In the shaft structure 120 of the present embodiment, as shown in FIG. 9B, the male member 121 is inserted into the female member 122 in which the impregnated fiber member 123 is bonded to the inner peripheral portion 122a. In the initial state, a closed curved gap S <b> 2 surrounded by the inner peripheral portion 123 a of the fiber member 123 and the contact portion P <b> 2 formed on the outer peripheral portion 121 c of the male member 121 can be formed. The contact portion P <b> 2 is a portion that can contact the inner peripheral portion 123 a of the facing fiber member 123.

  FIG. 10 is an enlarged view of a portion surrounded by a thick line in FIG. 9B. As shown in FIG. 10, the contact portion P2 (curve P2 in FIG. 10) is a line segment connecting points A11 and A12. Point A11 is a point where the inner peripheral portion 123a of the fiber member 123 and the root portion of the male tooth portion 121d are in contact with each other. Point A12 is a point where the inner peripheral portion 123a of the fiber member 123 and the tooth tip portion of the male tooth portion 121d are in contact with each other. In the contact portion P2 (curve P2), points A13 and A14 exist from the point A11 toward the point A12. Note that the positions of the points A13 and A14 can be changed as appropriate according to the state of use of the shaft structure 120. The contact portion P2 (curve P2) includes a contact portion P21 and a pressing portion P22. In the present embodiment, the contact portion P21 is configured by a line segment connecting the points A11 and A13. This abutting portion P21 is in an initial state (FIG. 9 (b) in the second embodiment) in which the male member 121 is twisted in the circumferential direction (left arrow direction indicated by white in FIG. 9 (b)). 9), the female member 122 is moved in the circumferential direction (FIG. 9B) while deforming the fiber member 123 by contacting the inner peripheral portion 123a of the opposing fiber member 123. This is a part where rotation can be started in the left direction of the arrow shown in white. Further, the pressing portion P22 is constituted by a line segment connecting the point A13 and the point A14. The pressing portion P22 is formed after the contact portion P21 and the fiber member 123 come into contact with each other by twisting in the circumferential direction of the male member 121 (the left arrow direction shown in white in FIG. 9B). It is a site | part which presses the inner peripheral part 123a of the fiber member 123 which opposes. Further, when the male member 21 is twisted in the circumferential direction (left arrow direction shown in white in FIG. 9B), the male pressure portion P22 presses the inner peripheral portion of the fiber member 123. Thus, the female member 122 can be rotated in the circumferential direction (the arrow left direction shown in white in FIG. 9B) while the fiber member 123 is deformed.

  The gap S <b> 2 is formed over the entire length along the axial direction of the male member 121. Thereby, when the male member 121 is twisted in the circumferential direction (left arrow direction shown in white in FIG. 9B), the cross-sectional shape of the fiber member 123 is deformed so that the gap S2 is absorbed, The contact area with the fiber member 123 in the contact part P21 and the pressing part P22 is increased. After that, the female member 122 rotates following the male member 121, and the pinion gear 104 (see FIG. 8) rotates.

  Here, as an example of the manufacturing method of the shaft structure 120, a male member 121 and a female member 122 having shapes shown in FIGS. 11A and 11B from a metal material (not shown) are used. The manufacturing method by performing sequentially the process of cutting out, the process of impregnating the fiber member 123 with rubber | gum etc., and the process of providing the fiber member 123 impregnated in the inner peripheral part 122a of the female-type member 122 can be mentioned.

  Moreover, as a manufacturing method of the fiber member 123, the following manufacturing methods can be selected suitably. For example, when the fiber member 123 of FIG. 11C is molded, first, an inner mold and an outer mold that can mold the inner peripheral portion 123a and the outer peripheral portion 123b are prepared. As a matter of course, the outer peripheral surface of the inner mold and the inner peripheral surface of the outer mold are provided with uneven shapes along the inner peripheral portion 123a and the outer peripheral portion 123b, respectively. And after filling the fiber (short fiber or long fiber, or cloth (sheet shape)) impregnated with rubber or resin between these two molds, pressure and pressure are applied to the fibers filled from the inner mold and the outer mold. A temperature is applied, and then the fiber is removed from the mold to obtain the fiber member 123 in which the inner peripheral portion 123a and the outer peripheral portion 123b are molded.

  In addition, as a manufacturing method of the fiber member 123, the cloth to be filled between the inner mold and the outer mold is finished in a cylindrical shape along the outer shape of the inner mold, and the cloth is aligned with the outer shape of the inner mold. There is also a method in which the fiber member 123 is molded by covering the inner mold and then applying pressure and temperature in the same manner as described above. In this case, since the cloth has elasticity, the fiber member 123 can be further molded along the concave and convex shapes of the inner mold and the outer mold. As a result, a molded product having a uniform surface can be manufactured without causing wrinkles or the like in the inner peripheral portion 123a or the outer peripheral portion 123b of the fiber member 123. By providing the fiber member 123 having a uniform surface on the inner peripheral portion 122a of the female member 122, the sliding resistance in the axial direction can be further reduced. In addition, generation | occurrence | production of said wrinkles etc. can be suppressed further by finishing a cloth into a cylindrical shape so that the direction which shows the elasticity of a cloth may correspond with the circumferential direction of the cylindrical fiber member 123 at least.

  As shown in FIG. 12, the manufacturing method in the case where the impregnated fiber member 123 is bonded to the inner peripheral portion 122 a of the female mold member 122 is the same as the female mold member 122 as it is. In addition, after applying an adhesive to the metal surface of the female mold member 122, fibers (short fibers or long fibers, or cloths) impregnated with rubber or resin between the female mold member 122 and the outer mold ( After filling the sheet shape)), pressure and temperature are applied from the outer mold, and then the outer mold is removed to obtain the member of FIG. 12 in which the fiber member 123 is bonded to the inner peripheral portion 122a of the female mold member 122. Further, similarly to the above manufacturing method, the cloth is finished in a cylindrical shape along the inner shape of the female member 122, and the cloth is put in a state along the inner diameter of the male member 21, and then pressure is applied. Twelve members may be obtained. In this case, since the cloth has elasticity, wrinkles and the like are hardly generated on the surface of the fiber member 123 bonded to the inner peripheral portion 122a of the female mold member 122, and the female mold member 122 having a uniform surface is manufactured. Therefore, the sliding resistance in the axial direction between the male member 121 and the female member 122 of the shaft structure 120 can be further reduced. As described above, the generation of the wrinkles and the like can be further suppressed by finishing the cloth in a cylindrical shape so that the direction in which the cloth exhibits elasticity matches at least the circumferential direction of the female member 122. is there.

(Characteristics of the shaft structure according to the second embodiment of the present invention)
According to the above configuration, the outer peripheral portion 21c of the male mold member 121 and the inner peripheral portion 122a of the female mold member 122 are provided by providing the fiber member 123 impregnated with rubber or the like in the inner peripheral portion 122a of the female mold member 122. Simultaneously solves both problems that are in a trade-off relationship such as suppression of unpleasant noise such as rattling noise generated between the two and reduction of axial sliding resistance between the male member 121 and the female member 122 be able to. Further, by improving the axial slidability between the male member 121 and the female member 122, lubricating oil is provided between the outer peripheral portion 121c of the male member 121 and the inner peripheral portion 122a of the female member 122. There is no need to supply the lubricant, and it is possible to save troubles such as lubrication. Furthermore, by impregnating the fiber member 123 with rubber or resin, it is possible to improve the wearability of the surface of the fiber member 123 generated between the fiber member 123 and the outer peripheral portion 121c of the male member 121.

  Further, as shown in the above configuration, in the initial state where the male member 121 is inserted into the female member 122, the gap S2 surrounded by the fiber member 123 and the contact portion P2 in the outer peripheral portion 121c of the male member 121. Can be formed. Thereby, when the male member 121 is twisted in the circumferential direction (left arrow direction indicated by white in FIG. 9B) in the initial state, the contact area between the fiber member 123 and the contact portion P2 is gradually increased. Can be expanded. As a result, the initial rigidity when the male member 121 is twisted can be reduced as compared with the conventional case, and a sudden transmission of large power to the shaft 103 can be suppressed. Thus, it is possible to prevent the driver from feeling uncomfortable as in the past (a feeling of strangeness that the force required to operate the steering wheel 102 suddenly decreases immediately after the operation of the steering wheel 102 is started).

  Further, as shown in the above-described configuration, when the twisting of the male member 121 in the initial state in the circumferential direction (the left arrow direction in FIG. 9B) is started, The contact portion P21 is in contact with a portion of the inner peripheral portion 123a of the fiber member 123 that faces the contact portion P21, so that the fiber member 123 that faces the contact portion P21 is gently deformed, and the circumferential direction ( The rotation of the female member 122 in the direction indicated by the white arrow in FIG. 9B can be started. In addition, the pressing portion P22 of the contact portion P2 is configured such that the contact portion P21 and the inner peripheral portion of the fiber member 123 come into contact with the portion of the inner peripheral portion 123a of the fiber member 123 that faces the contact portion P21. By pressing the portion of 123a facing the pressing portion P22, the fiber member 123 facing the pressing portion P22 is deformed, and the female member 122 is moved in the circumferential direction (indicated by the white arrow in FIG. 9B). It can be fully rotated toward the left). That is, contact with the fiber member 123 gradually spreads from A12 toward A14 toward the A14, and then contact with the fiber member 123 gradually spreads from A14 toward A13. The contact area between the fiber member 123 and the contact portion P2 can be expanded with higher accuracy by gradually bringing the component parts into contact with the inner peripheral portion 123a of the fiber member 123 in order, and as a result, The initial rigidity when the mold member 121 is twisted can be further reduced.

  The initial rigidity in the present embodiment is a line connecting points A11 and A12 when the male member 121 is twisted in the circumferential direction (left arrow direction indicated by white in FIG. 9B). The minute (curve P2 in FIG. 10) may mean the rigidity when contacting the inner peripheral portion 123a (see FIG. 10) of the opposing fiber member 123 until the moment when the gap S2 (see FIG. 10) disappears. , Meaning the rigidity up to the moment when the line segment connecting the points A11, A13, A14 (curves P21, P22 in FIG. 10) contacts the inner peripheral portion 123a (see FIG. 10) of the opposing fiber member 123. It may be.

  As mentioned above, although embodiment of this invention was described based on drawing, 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 each of the above-described embodiments, the example in which the shaft structure according to the present embodiment is applied to the vehicle steering shafts 3 and 103 has been described. However, the present invention is not limited to this and is used in various industrial machines. Applicable to shaft.

  Further, in each of the above embodiments, the example in which the fiber members 23 and 123 are impregnated with rubber or the like has been described. As long as the fiber has a low sliding resistance, a cloth in which the fiber is formed into a sheet shape may be used. 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 side, or expands / contracts to both the vertical / horizontal direction.

  Further, as a technique for adhering the fiber members 23 and 123 impregnated with rubber to the outer peripheral portion 21c of the male member 21 and the inner peripheral portion 122a of the female member 122, for example, the fiber member 23 impregnated with rubber, A rubber layer integrated with the fiber members 23 and 123 is provided on the back surface of 123 (the surface on the side bonded to the outer peripheral portion 21c of the male member 21 and the inner peripheral portion 122a of the female member 122). The metal surface (the surface of the outer peripheral portion 21c of the male member 21 and the surface of the inner peripheral portion 122a of the female member 122) may be bonded with an adhesive. Thereby, the adhesive strength of a metal surface and the fiber members 23 and 123 can be improved.

  Moreover, in each said embodiment, the clearance gaps S1 and S2 were described about the example which forms over the full length along the axial direction of the female type | mold member 22 and the male type | mold member 121. As shown in FIG. However, the gaps S1 and S2 are not necessarily formed over the entire length along the axial direction of the female mold member 22 and the male mold member 121 as long as they are within the range in which the effects of the present invention can be achieved. It may be formed in a part along the axial direction of the mold member 22 and the male mold member 121.

  Moreover, in each said embodiment, the contact part P1, P2 (contact part P11, 21 and press part P12, 22) described the example which draws a curve. However, the contact portions P1 and P2 (the contact portions P11 and 21 and the pressing portions P12 and 22) do not necessarily need to draw a curve as long as the effects of the present invention can be achieved, for example, draw a straight line. It may be a thing.

DESCRIPTION OF SYMBOLS 1,101 Electric power steering apparatus 2,102 Steering wheel 3,103 Steering shaft (shaft)
4, 104 Pinion gear 5, 105 Rack gear 6, 106 Rack shaft 7, 107 Tie rod 8, 108 Wheel 9, 109 Input shaft 10, 110 Output shaft 11, 111 Torsion bar 12, 112 Torque sensor 13, 113 Controller 14, 114 Driver 15, 115 Electric motor 17, 117 Deceleration mechanism 18, 118 Conversion mechanism 20, 120 Shaft structure 21, 121 Male member 21a, 121a Base shaft portion 21b, 121b Convex portion 21c, 121c Outer peripheral portion 21d, 121d Male tooth portion 21e, 121e Male tooth bottom part 22, 122 Female member 22a, 122a Inner peripheral part 22b, 122b Female tooth part 22c, 122c Female tooth base part 23, 123 Fiber member 23a, 123a Inner peripheral part 23b, 123b Outer peripheral part P1, P2 Contact Part P11, P21 Contact part P12, P22 Press Part S1, S2 Clearance

Claims (8)

A structure for a shaft that is assembled to a shaft capable of transmitting power and is configured by inserting a male member into a female member so as to be slidable in the axial direction,
A male member having a plurality of male teeth and a plurality of male teeth bottoms formed on the outer periphery;
A plurality of female teeth and a plurality of female teeth bottom are formed on the inner periphery, and the female member into which the male member is inserted;
Between the male member and the female member, the surface of the outer peripheral portion of the male member is in close contact with the surface of the outer peripheral portion, and the tooth tip portion of the female tooth portion and the root of the female tooth portion A fiber member impregnated with rubber or resin, which is provided so as to contact the part in advance ;
With
In the initial state where the male member is inserted into the female member,
Of the inner peripheral part of the female member and the female mold member, a part facing the fiber member between the female tooth part and the female tooth bottom part, and the female tooth part in which the fiber member is in contact in advance A structure surrounded by a tooth tip portion and a root portion of the female tooth portion is formed. Of the inner peripheral part of the female mold member, the part facing the fiber member between the female tooth part and the female tooth bottom part,
An abutting portion that abuts against the fiber member when starting to twist in the circumferential direction of the male member in the initial state;
After the contact portion and the fiber member are in contact, a pressing portion that is pressed against the fiber member;
The shaft structure according to claim 1, comprising: A structure for a shaft that is assembled to a shaft capable of transmitting power and is configured by inserting a male member into a female member so as to be slidable in the axial direction,
A male member having a plurality of male teeth and a plurality of male teeth bottoms formed on the outer periphery;
A plurality of female teeth and a plurality of female teeth bottom are formed on the inner periphery, and the female member into which the male member is inserted;
Between the male member and the female member, the surface of the inner peripheral portion of the female member is brought into close contact with the surface of the inner peripheral portion, and the tooth tip portion of the male tooth portion and the male tooth portion are covered. A fiber member impregnated with rubber or resin, which is provided so as to come into contact with the base portion of
With
In the initial state where the male member is inserted into the female member,
Of the outer peripheral portion of the fiber member and the male member, a portion facing the fiber member between the male tooth portion and the male tooth bottom portion, and the male tooth portion in which the fiber member abuts in advance A structure surrounded by a tooth tip portion and a root portion of the male tooth portion is formed. Of the outer periphery of the male member, the portion facing the fiber member between the male tooth part and the male tooth bottom part,
When the twisting of the male member in the circumferential direction is started in the initial state, the female member can be started to rotate in the circumferential direction while deforming the fiber member by contacting the fiber member. A contact portion;
A pressing portion capable of rotating the female member in the circumferential direction while deforming the fiber member by pressing the opposing fiber member after the contact portion and the fiber member are in contact;
The shaft structure according to claim 3, wherein: Used for a shaft structure that is assembled to a shaft capable of transmitting power and is configured by slidably inserting a plurality of female teeth and a plurality of female teeth bottoms into a female member formed on the inner periphery. A male member,
A plurality of male teeth formed on the outer periphery;
A plurality of male tooth bottoms formed on the outer periphery;
Covers the surface of the outer peripheral portion in close contact with the plurality of Okha portions and the surface of the outer peripheral portion of said plurality of male teeth bottom, when inserted into the female member, the female and the male member Between the members, a fiber member impregnated with rubber or resin, which is provided so as to come into contact with the tooth tip portion of the female tooth portion and the root portion of the female tooth portion in advance ,
With
In the initial state of being inserted into the female member,
Of the inner peripheral part of the female member and the female mold member, a part facing the fiber member between the female tooth part and the female tooth bottom part, and the female tooth part in which the fiber member is in contact in advance A male member characterized in that a space surrounded by the tooth tip portion and the root portion of the female tooth portion is formed. Of the inner peripheral part of the female mold member, the part facing the fiber member between the female tooth part and the female tooth bottom part,
An abutting portion that abuts against the opposing fiber member when starting to twist in the circumferential direction of the male member in the initial state;
After the contact portion and the fiber member are in contact, a pressing portion that is pressed by the opposing fiber member;
The male member according to claim 5, wherein the male member is used in a structure for a shaft that is configured to be inserted into a female member having a shape. Used in a shaft structure that is assembled to a shaft capable of transmitting power and is configured by a slidably inserted male member having a plurality of male teeth and a plurality of male teeth bottoms formed on the outer periphery. A female member,
A plurality of female teeth formed on the inner periphery,
A plurality of female tooth bottoms formed on the inner periphery,
Covering the surface of the inner peripheral portion in close contact with the surfaces of the inner peripheral portions of the plurality of female tooth portions and the plurality of female tooth bottom portions, and when the male member is inserted, the male member and the Between the female member, a fiber member impregnated with rubber or resin, which is provided so as to contact the tooth tip part of the male tooth part and the root part of the male tooth part in advance ,
With
In the initial state where the male member is inserted,
Of the outer peripheral portion of the fiber member and the male member, a portion facing the fiber member between the male tooth portion and the male tooth bottom portion, and the male tooth portion in which the fiber member abuts in advance A female member characterized in that a gap surrounded by a tooth tip portion and a root portion of the male tooth portion is formed. Of the outer periphery of the male member, the portion facing the fiber member between the male tooth part and the male tooth bottom part,
When the twisting of the male member in the circumferential direction is started in the initial state, the female member can be started to rotate in the circumferential direction while deforming the fiber member by contacting the fiber member. A contact portion;
A pressing portion capable of rotating the female member in the circumferential direction while deforming the fiber member by pressing the opposing fiber member after the contact portion and the fiber member are in contact;
The female member according to claim 7, wherein the female member is used in a structure for a shaft configured by inserting a male member having a shape.