JP2010281364A - Connecting structure and steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting structure and a steering device using such a connecting structure having superior fastening workability, having a smaller number of portions to be changed with respect to an existing one, and which can be inexpensively configured. <P>SOLUTION: The connecting structure is for connecting a shaft and a yoke by fastening of a bolt structure attached to a pair of flange parts extending in a radial direction from a boss part in a state of inserting an end of the shaft into the boss part of the yoke provided in a universal joint, and reducing a diameter of the boss part. A cylinder secured to the end of the shaft inserted into the boss part is internally fit in a fitting hole provided in the flange part. A bolt member of the bolt structure is inserted through the cylinder, and fastening is carried out by the bolt structure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a universal joint / shaft coupling structure and a steering device used in a coupling portion of a steering shaft.

  As shown in FIG. 14, the steering device 1 has a plurality of shafts 4 disposed between a steering wheel 2 and a steering gear 3. That is, the rotational torque applied to the steering wheel 2 is transmitted to the steering gear 3 between the steering wheel 2 and the steering gear 3 having different axial directions. If the steering shaft 4 cannot be arranged in a straight line due to the space in the vehicle, etc., one or more shaft couplings 5 are arranged between the steering shafts 4 and the steering gear 3 can be rotated accurately even when the steering shaft 4 is bent. It is possible to transmit exercise.

  As the shaft joint (universal joint) 5, a cardan universal joint which is a kind of universal joint as shown in FIG. 15 may be used. Here, the cardan type universal joint has a pair of wing pieces 6 and 7 connected to a pair of U-shaped main body portions 13 and 14 via a cross shaft 8, whereby the main body portions 13 and 14 are connected. Rotational force can be transmitted even if the shaft centers are not positioned on a straight line. A coupling structure m to which the shaft 4 is coupled is provided on the bottom wall of the main body 13.

  As shown in FIGS. 15 and 16, the coupling structure m includes a structure in which the male serration 12 at the end of the shaft 4 is inserted into the female serration 11 of the yoke 9 of the universal joint 5 and bolted.

  That is, the yoke 9 has a boss portion 15 into which the male serration 12 at the end of the shaft 4 is fitted, and a pair of flange portions 16a and 16b protruding from the boss portion 15 in the outer diameter direction. In this case, the boss portion 15 is a cylindrical body having a slit-like cutout portion extending in the axial direction on the peripheral wall thereof, and flange portions 16a and 16b project from the both ends of the cutout in parallel.

  Further, the through hole 17 is provided in one flange portion 16a, and the screw hole 18 is provided in the other flange portion 16b. Then, the screw shaft 20 a of the bolt member 20 is inserted into the through hole 17, and the screw shaft 20 a is screwed into the screw hole 18. That is, when the screw shaft 20a of the bolt member 20 is screwed into the screw hole 18, the flange portions 16a and 16b approach each other. By this approach, the diameter of the boss 15 is reduced, and the male serration 12 at the end of the shaft 4 can be tightened without looseness, and the shaft coupling (universal joint) 5 and the shaft (shaft) 4 can be coupled. it can.

  Further, as shown in FIG. 15, the male serration 12 is provided with a circumferential recess 21, and the screw shaft 20 a of the bolt member 20 is engaged with a part of the recess 21. As a result, the shaft 4 is positioned with respect to the yoke 10. That is, the bolt member 20 performs the tightening of the shaft 4 by the boss portion 15 and the positioning of the shaft 4.

  However, in the case shown in FIG. 15 and FIG. 16, the positioning is not stable until the fastening of the bolt member 20 is completed. For this reason, until the fastening of the bolt member 20 is completed, the operator needs to maintain the position so that the shaft 4 does not deviate from a predetermined axial position. For this reason, it was inferior to joint workability | operativity, and the working time was long.

  Therefore, conventionally, there has been proposed a coupling structure that prevents the shaft from being displaced when the bolt member 20 is fastened (Patent Document 1). As shown in FIG. 17, the device described in Patent Document 1 is provided with an engagement convex portion (engagement piece) 25 that can be elastically deformed on the shaft 4 side and the engagement convex portion 25 on the yoke 10 side. The engaging recess 26 is provided.

  The engagement piece 25 of this example is provided with a small-diameter shaft portion at the distal end of the shaft 4 and is provided at the small-diameter shaft portion, and is inclined in the outer diameter direction from the shaft distal end side toward the shaft proximal end side. It consists of an inclined piece. For this reason, if the male serration 12 of the shaft 4 is inserted into the boss portion 15 of the yoke 10, the engagement piece 25 is pressed toward the inner diameter side by the female serration 11 of the boss portion 15, and insertion is permitted. Become. And if the engagement piece 25 is inserted to the position corresponding to the engagement recessed part 26, the press to the internal diameter side to the engagement piece 25 will be cancelled | released. If released in this way, the engagement piece 25 returns to the original state of the expanded diameter by the elastic restoring force. As a result, the engagement piece 25 is engaged with the engagement recess 26 to prevent the shaft 4 from coming off from the yoke 10.

JP 2007-292165 A

  However, in the structure shown in FIG. 17, an engaging convex portion (engaging piece) 25 that can be elastically deformed is provided on the shaft 4 side, and an engaging concave portion 26 that engages with the engaging convex portion 25 is provided on the yoke 10 side. Therefore, it is necessary to increase the number of parts and to complicate the shape of each member. Moreover, as shown in FIG. 17, when the engagement convex portion 25 is provided on the shaft 4 side, it is necessary to provide the engagement convex portion 25 by further projecting a small diameter shaft portion at the tip of the male serration 12. For this reason, the axial direction length of the boss | hub part 15 becomes large, and size reduction cannot be achieved. In addition, Patent Document 1 also describes a configuration in which an engagement concave portion 26 is provided on the shaft 4 side and an engagement convex portion is provided on the yoke 10 side. However, also in this case, the number of parts is increased and the shape of each member is complicated. In addition, even in this case, it is necessary to displace the engaging convex portion 25 in the axial direction from the position where the bolt member is disposed, and the axial length of the boss portion 15 becomes large.

  Thus, in the thing of patent document 1, the engagement convex part 25 engages with the engagement recessed part 26, and the removal from the yoke 10 of the shaft 4 can be prevented. The movement of the shaft 4 in the insertion direction with respect to the yoke 10 cannot be restricted. For this reason, when screwing the bolt member, the movement of the shaft 4 may move, and a stable tightening action cannot be performed.

  Moreover, in the case shown in FIG. 17, in order to release the coupled state, it is necessary to push the release tool 27 into the engagement recess 26 from the outer diameter side of the yoke and press the engagement projection 25. For this reason, a separate release tool is required and the release work is troublesome.

  In view of the above-described problems, the present invention provides a coupling structure that is excellent in fastening workability, can be configured at a low cost with less change parts than an existing one, and a steering apparatus using such a coupling structure I will provide a.

  The coupling structure of the present invention is a tightening of a bolt structure attached to a pair of flange portions extending in an outer diameter direction from the boss portion in a state where the end portion of the shaft is inserted into a boss portion of a yoke provided in the universal joint. A connecting structure for connecting the shaft and the yoke by reducing the diameter of the boss portion by providing a cylindrical body on the flange portion to be engaged with an end portion of the shaft inserted into the boss portion. The bolt member is inserted into the fitting hole, the bolt member having the bolt structure is inserted into the cylindrical body, and tightening by the bolt structure is performed.

  According to the coupling structure of the present invention, when the cylinder is fitted into the fitting hole provided in the flange portion, the cylinder is locked to the end of the shaft. For this reason, the end of the shaft relative to the yoke is positioned. And the bolt member of a bolt structure can be penetrated in a cylinder body in the state positioned in this way, and clamping | tightening by this bolt structure can be performed. Moreover, if the bolt member of a bolt structure is screwed out, this bolt member can be removed from a flange part, and, thereby, the coupling | bonding state of a shaft and a yoke can be cancelled | released. In addition, the shape of the end portion of the shaft can be kept the conventional shape, and it is not necessary to provide a new locking portion or the like on the yoke side.

  A slit extending in the axial direction may be provided on the peripheral wall of the cylindrical body, and the cylindrical body may be press-fitted into a fitting hole provided in the flange portion. As described above, if the cylinder is press-fitted into the fitting hole, the removal of the cylinder can be restricted when the cylinder is fitted into the fitting hole. Further, by providing the slit, it is possible to improve the diameter reduction of the cylindrical body. It is preferable that the cylindrical body is provided with a tapered surface having a diameter reduced toward the press-fitting start end at the press-fitting start end portion of the outer peripheral surface. By providing the tapered surface, the tapered surface serves as a guide at the start of press-fitting. Moreover, it is also possible to comprise the said cylinder with resin.

  The bolt member seating surface of the bolt structure is in direct contact with the seating surface of the fitting hole, and a washer is interposed between the seating surface of the bolt member of the bolt structure and the fitting hole. It may be.

  It is preferable that a gap be provided between the seat surface of the bolt member or the seat surface of the bolt structure made of a washer and the cylindrical body.

  The bolt member of the bolt structure can be screwed into a nut member whose flange portion is a separate member. Moreover, while providing the through-hole into which the bolt member of a bolt structure is penetrated in one flange part, the internal thread part which this bolt member screws together may be provided in the other flange part. In this case, a nut member having a female thread portion into which a bolt member having a bolt structure is screwed may be integrated with the other flange portion.

  The universal joint includes, for example, an outer joint member in which a plurality of track grooves are formed on an inner diameter surface, an inner joint member in which a plurality of track grooves are formed on an outer diameter surface, and a track groove and an inner joint of the outer joint member. A plurality of torque transmitting balls as torque transmitting members which are interposed between the track grooves of the members and transmit torque; and balls interposed between the inner diameter surface of the outer joint member and the outer diameter surface of the inner joint member Is a fixed type constant velocity universal joint provided with a retainer for holding the ball, and is provided with a backlash filling mechanism for filling a gap between the track groove and the ball.

  In such a fixed type constant velocity universal joint, even if the bottom surface of the track groove is a track offset type in which the bottom surface of the track groove is constituted by a single arc portion, the undercut free in which the bottom surface of the track groove is composed of an arc portion and a straight portion. It may be a type.

  Further, the universal joint may be a double cardan universal joint.

  The steering apparatus according to the present invention uses the above-described coupling structure. For this reason, the bolt member of a bolt structure can be inserted in a cylinder body in the state where the axis was positioned, and the bolt structure can be tightened.

  In the coupling structure of the present invention, the bolt member having the bolt structure can be inserted into the cylindrical body in the positioned state, and tightening by the bolt structure can be performed. For this reason, the operator can screw the bolt member of the bolt structure without worrying about the displacement of the shaft, can improve workability, and can perform a stable coupling operation in a short time. It can be carried out. In addition, the shape of the end of the shaft can be maintained at the conventional shape, and it is not necessary to provide a new locking portion on the yoke side, so the number of parts to be changed is small compared to the existing one, and the configuration is low cost. Can do.

  If the cylindrical body is press-fitted into the fitting hole, the removal of the cylindrical body is restricted, stable positioning can be performed, and workability is excellent. Further, by providing the slit, the cylindrical body can be elastically reduced in diameter during press-fitting to improve the press-fitting property, and damage or breakage of the cylindrical body can be prevented during press-fitting. By providing the cylindrical body with a tapered surface, the tapered surface serves as a guide at the start of press-fitting, and the press-fitting start is stabilized. If the cylindrical body is made of resin, it is possible to reduce the weight and improve the productivity.

  When the washer is not used, the number of parts can be reduced, and the assembling property can be improved and the cost can be reduced. Moreover, when using a washer, it is possible to prevent the head of the bolt member from sinking (sinking of the seat surface) or to exert a stable tightening force on the bolt member.

  When a nut member is used, it is not necessary to provide a screw hole in the flange portion, and workability can be improved. When the flange portion is provided with a female screw portion into which a bolt member of a bolt structure is screwed, it is not necessary to use a nut member, the number of parts can be reduced, and the assembling property and the cost can be reduced. be able to.

  The fixed type constant velocity universal joint has a clearance between the outer ring track groove and the inner ring track groove through a ball in terms of function and processing, and this clearance is either the inner ring or the outer ring in the neutral state of the joint. Is the amount of movement when the other is moved in the radial or axial direction, and is called a radial clearance or an axial clearance depending on the direction of movement. These clearances greatly affect the circumferential play (rotational backlash) between the inner and outer rings, and the larger the track groove clearance, the greater the rotational backlash. On the other hand, such a rotational backlash can be filled by providing a backlash filling mechanism for filling the gap between the track groove and the ball.

  Further, the universal joint may be a double cardan universal joint. The cardan type universal joint has a simple structure. However, if the cardan joint alone has a crossing angle between two axes, it is inevitable that the speed is mechanically inconstant. Therefore, if a double cardan universal joint obtained by combining two cardan universal joints is used, rotational fluctuations of the cardan universal joint itself can be offset, and constant velocity can be ensured.

  The steering device of the present invention uses the above-described coupling structure, and can perform a stable coupling operation in a short time.

It is a top view shown in the partial cross section of the coupling structure of 1st Embodiment of this invention. It is a front view shown with the partial cross section of the coupling structure shown in the said FIG. It is the YY sectional view taken on the line in the said FIG. It is a principal part expanded sectional view of the coupling structure shown in the said FIG. It is sectional drawing which shows the relationship between the flange part and cylinder in the coupling structure shown in FIG. It is sectional drawing which shows the relationship between the flange part in a coupling structure, and the cylinder of a modification. It is a front view of the cylinder shown in the said FIG. It is a principal part expanded sectional view of the cylinder shown in the said FIG. It is a principal part expanded sectional view of the coupling structure of 2nd Embodiment of this invention. It is a principal part expanded sectional view of the coupling structure of 3rd Embodiment of this invention. It is a principal part expanded sectional view of the coupling structure of 4th Embodiment of this invention. It is sectional drawing which shows the joint structure whose universal joint is a fixed type constant velocity universal joint. It is sectional drawing which shows the joint structure whose universal joint is a double cardan type universal joint. It is a perspective view of a general steering device. It is a top view shown with the partial cross section of the conventional joint structure. It is sectional drawing of the conventional coupling structure. It is sectional drawing of the other conventional coupling structure.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  1 to 3 show a coupling structure according to the present invention. This coupling structure is for coupling the universal joint 30 and the shaft (shaft) 31 in the steering device 1. The universal joint 30 in this case is a cardan type universal joint in which a pair of U-shaped main body portions 42 and 43 are connected via a cross shaft 40.

  The main body portions 42 and 43 each have a pair of wing piece portions 34 and 35, and the wing piece portions 34 and 35 of the main body portions 42 and 43 are connected via a cross shaft 40. A coupling structure M according to the present invention, in which the shaft 31 is coupled, is provided on the yoke 32 provided on the bottom wall of each main body 42.

  The coupling structure M includes a boss portion 45 and a pair of parallel flange portions 46 and 47 extending from the boss portion 45 in the outer diameter direction. The boss portion 45 is a cylindrical body having a slit-like cutout portion along the axial direction, and flange portions 46 and 47 extend from the cutout end portion in the outer diameter direction. A female serration 48 is provided on the inner diameter surface of the boss portion 45. As will be described later, the female serration 48 is provided at the end of the shaft 31 and is engaged with the male serration 49.

  As shown in FIGS. 3 to 5, one flange portion 46 is provided with a through hole 50 extending in a direction orthogonal to the axial direction of the boss portion 45. The through hole 50 includes a main body portion 50 a and an opening-side large-diameter portion 50 b opposite to the other flange portion 47. In this case, it crosses a part of the female serration 48 of the boss portion 45.

  The other flange portion 47 is formed with a hole portion 51 that faces the main body portion 50 a of the through hole 50 of the one flange portion 46 and a screw hole 52 that is connected to the hole portion 51. At this time, in the free state, the axial center of the through hole 50, the axial center of the hole 51, and the axial center of the screw hole 52 coincide. The hole 51 also crosses a part of the female serration 48 of the boss portion 45. In this free state, a gap 53 of a predetermined size is provided between the opposing surfaces 46a and 47a facing the flange portions 46 and 47.

  A cylindrical body 54 is fitted into the main body portion 50a of the through hole 50 of the one flange portion 46 and the hole portion 51 of the other flange portion 47, and the bolt member 56 of the bolt structure 55 is inserted into the cylindrical body 54. It will be inserted from 46 side. That is, the body portion 50a of the through hole 50 of the flange portion 46 and the hole portion 51 of the other flange portion 47 constitute a fitting hole 59 into which the cylindrical body 54 is fitted.

  As shown in FIG. 5, when the hole diameter of the fitting hole 59 formed by the main body portion 50a of the through hole 50 and the hole portion 51 of the other flange portion 47 is Dy and the outer diameter of the cylindrical body 54 is Di In addition, if Dy> Di, the axial length of the fitting hole 59 is Ly, and the axial length of the cylindrical body 54 is Li, then Ly> Li. Thereby, as shown in FIG. 4, the cylindrical body 54 can be easily inserted (inserted). In addition, the other end edge 54 b of the cylinder body 54 is retracted from the large diameter portion 50 b of the through hole 50 in a state where the one end edge 54 a of the cylinder body 54 is in contact with the stepped surface 51 a of the hole portion 51.

  Further, as shown in FIG. 2, the male serration 49 at the end of the shaft 31 fitted into the boss portion 45 is provided with a circumferential groove 57 having a circular arc shape in which the cylindrical body 54 is fitted (engaged). ing. The curvature radius of the bottom surface of the circumferential groove 57 and the curvature radius of the outer diameter surface (outer peripheral surface) of the cylindrical body 54 substantially coincide with each other. For this reason, when the cylindrical body 54 is engaged with the circumferential groove 57, the bottom surface of the circumferential groove 57 and the outer diameter surface of the cylindrical body 54 are closely engaged. For this reason, the shaft 31 and the yoke 32 can be reliably positioned with respect to the axial direction in a state where the cylindrical body 54 is fitted in the fitting hole 59.

  In this case, the bolt member 56 of the bolt structure 55 is inserted into the cylindrical body 54 from the one flange portion 46 side and screwed into the screw hole 52, but the washer 60 is fitted into the large diameter portion 50 b of the through hole 50. Combined. That is, as shown in FIG. 4, the seat surface 61A, which is the back surface 60a of the washer 60, and the bottom surface 64 of the large diameter portion 50b are in direct contact with each other. For this reason, the washer 60 is clamped by the head part 56a of the bolt member 56 and the seat surface 61B. At this time, as described above, since the other end edge 54b of the cylinder body 54 is retracted from the large diameter portion 50b of the through hole 50, the gap between the back surface 60b of the washer 60 and the other end edge 54b of the cylinder body 54 is reduced. A gap S having a predetermined size is formed.

  Next, a method for coupling the shaft 31 and the boss portion 45 using the coupling structure M configured as described above will be described. First, the male serration 49 at the end of the shaft 31 is inserted (inserted) into the boss portion 45. That is, the male serration 49 is fitted to the female serration 48 of the boss portion 45. Next, the cylindrical body 54 is inserted (inserted) into the fitting hole 59. Thereby, as shown in FIG. 2 etc., the cylinder 54 is engaged with the circumferential groove 57 provided in the male serration 49 at the end of the shaft 31.

  As described above, in the state where the cylindrical body 54 is fitted in the fitting hole 59, the shaft 31 is positioned at a predetermined position in the boss portion 45, and moves in the axial direction and rotates in the circumferential direction with respect to the boss portion 45. Is regulated. Next, with the washer 60 fitted into the large diameter portion 50b of the through hole 50, the male screw 56b of the bolt member 56 of the bolt structure 55 is inserted into the cylindrical body 54 from the one flange portion 46 side, and the other flange is inserted. Screwed into the screw hole 52 of the portion 47.

  In this case, if the bolt member 56 is screwed into the screw hole 52, the one flange portion 46 and the other flange portion 47 approach each other. That is, the size of the gap 53 between the flange portions 46 and 47 is small. As a result, the diameter of the boss portion 45 is reduced, the female serration 48 and the male serration 49 are brought into close contact with each other, and the shaft 31 is coupled to the boss portion 45 without play.

  According to the coupling structure of the present invention, the bolt member 56 of the bolt structure 55 can be inserted into the cylindrical body 54 with the shaft 31 positioned, and the bolt structure 55 can be tightened. For this reason, the operator can screw the bolt member 56 of the bolt structure 55 without worrying about the positional deviation of the shaft, so that the workability can be improved and the coupling can be stably performed in a short time. Work can be done. Moreover, the shape of the end portion of the shaft 31 can be maintained at the conventional shape, and it is not necessary to provide a new locking portion or the like on the yoke 32 side. can do.

  A gap S is provided between the seat surface 61 </ b> A of the bolt structure 55 including the washer 60 and the other end edge 54 b of the cylindrical body 54. By providing this gap S, even if the cylindrical body 54 is provided, a stable tightening operation can be performed without hindering the tightening operation by the bolt structure 55.

  On the other hand, since the female threaded portion (screw hole) 52 into which the bolt member 56 of the bolt structure 55 is screwed is provided in the flange portion 47, it is not necessary to use a nut member, and the number of parts can be reduced, and assembly is performed. Improvement and cost reduction can be achieved.

  By the way, as the cylinder 54, as shown to FIG. 6 and FIG. 7, the slit 62 extended in an axial direction may be provided in the surrounding wall. In this case, when the hole diameter of the fitting hole 59 formed by the main body portion 50a of the through hole 50 and the hole portion 51 of the other flange portion 47 is Dy, and the outer diameter of the cylindrical body 54 in the free state is Di. , Dy <Di, where the axial length of the fitting hole 59 is Ly and the axial length of the cylindrical body 54 is Li, Ly> Li.

  Since Dy <Di, when the cylindrical body 54 is inserted into the fitting hole 59, the cylindrical body 54 is reduced in diameter and press-fitted. At this time, since the cylindrical body 54 has the slit 62, the cylindrical body 54 is stably reduced in diameter.

  As described above, when the cylindrical body 54 shown in FIGS. 6 and 7 is used, the cylindrical body 54 is press-fitted into the fitting hole 59. For this reason, when the cylindrical body is fitted into the fitting hole 59, the cylindrical body 54 can be prevented from coming off. Further, by providing the slit 62, the diameter reduction of the cylindrical body can be improved, and the press-fitting work can be facilitated.

  By the way, even if the slit 62 is provided as shown in FIG. 6 and FIG. 7 or the slit 54 is not provided as shown in FIG. It may be a material. Various metal materials such as carbon steel, steel plate, and spring steel can be used as the metal material, and various resin materials such as plastic can be used as the resin material.

  In particular, in the case of the cylindrical body 54 provided with the slits 62, the slit 62 can improve the diameter reduction of the cylinder, so that even if a resin material is used or a diameter reduction force is applied when press-fitting. It is difficult to damage or break. On the other hand, if a resin material is used for the cylindrical body 54 that does not have a slit, there is a risk of damage or breakage due to application of a diameter reducing force during press-fitting. For this reason, by providing the slit 62, it is possible to use a resin material for the cylindrical body 54, and it is possible to achieve weight reduction and cost reduction.

  If the cylinder 54 is press-fitted into the fitting hole 59, as shown in FIG. 8, the cylinder 54 is reduced in diameter by a predetermined taper angle α toward the press-fit start end of the outer peripheral surface. A tapered surface 63 may be provided. By providing the tapered surface 63 on the cylindrical body 54, the tapered surface 63 serves as a guide at the start of press-fitting, and the press-fitting start is stabilized. In addition, even if it is the cylinder 54 which does not have the slit shown in FIG.

  Next, FIG. 9 shows the bolt structure 55 that does not use the washer 60. That is, the seat surface 65a of the seat portion 65 of the head portion 56a of the bolt member 56 is directly fitted to the bottom surface 64 of the large diameter portion 50b of the one flange portion 46. The coupling structure M shown in FIG. 9 has the same configuration as the coupling structure M shown in FIG. Therefore, in FIG. 9, the same members as those of the coupling structure M shown in FIG.

  Therefore, even the coupling structure M shown in FIG. 9 has the same effects as the coupling structure M shown in FIG. In addition, when the washer 60 is not used, the number of parts can be reduced, and the assemblability can be improved and the cost can be reduced. However, as shown in FIG. 1, when a washer is used, it is possible to prevent the head portion 56a of the bolt member 56 from being depressed (sinking of the seat surface), or to allow the bolt member 56 to exhibit a stable tightening force.

  As shown in FIG. 9, even when no washer is used, a gap S is provided between the seat portion 65 of the head portion 56 a of the bolt member 56 and the other end edge 54 b of the cylindrical body 54. By providing the clearance S, even if the cylinder body 54 is provided, a stable tightening operation can be performed without hindering the tightening operation by the bolt structure 55.

  In FIG. 10, a nut member 66 is attached to the flange portion 47 without providing a screw hole in the flange portion 47 itself. That is, the nut member 66 includes a small diameter portion 66a and a large diameter portion 66b. The flange portion 47 is provided with a through hole 67. The through hole 67 includes a first hole 67a on one flange portion 46 side, a second hole 67b on the opposite side to the flange portion 46, and a space between the first hole 67a and the second hole 67b. And a third hole 67c having a small diameter.

  In this case, the small diameter portion 66 a of the nut member 66 is fitted into the second hole portion 67 b of the flange portion 47. For example, the small-diameter portion 66a can be integrated by press-fitting the small-diameter portion 66a into the second hole portion 67b, but may be integrated by a joining means such as welding.

  In this coupling structure M, the body portion 50a of the through hole 50 of the flange portion 46 and the first hole portion 67a of the flange portion 47 constitute a fitting hole 59 into which the cylindrical body 54 is fitted. That is, the cylindrical body 54 is fitted into the fitting hole 59 in a state where the one end edge 54a is in contact with the step surface 68 of the first hole portion 67a. Then, with the washer 60 fitted to the large diameter portion 50 b of the through hole 50, the bolt member 56 is inserted from the one flange portion 46 side and screwed to the screw portion 69 of the nut member 66.

  Therefore, even in the coupling structure M shown in FIG. 10, if the bolt member 56 is screwed with respect to the screw portion 69 of the nut member 66, the one flange portion 46 and the other flange portion 47 are connected. Approach each other. As a result, the diameter of the boss 45 is reduced, the female serration 48 and the male serration 49 are brought into close contact with each other, and the shaft 31 is coupled to the boss 45 without play.

  Next, in FIG. 11, the nut member 66 is not attached to the flange portion 47, but the nut member 73 is screwed to the front end portion of the male screw 56 b of the bolt member 56 protruding from the flange portion 47. For this reason, the flange portion 47 is provided with a through hole 71 including a first hole portion 71 a on the one flange portion 46 side and a second hole portion 71 b on the opposite side to the one flange portion 46.

  In this coupling structure M, the main body portion 50a of the through hole 50 of the flange portion 46 and the first hole portion 71a of the flange portion 47 constitute a fitting hole 59 into which the cylindrical body 54 is fitted. That is, the cylindrical body 54 is fitted into the fitting hole 59 in a state where the one end edge 54a is in contact with the step surface 72 of the first hole 71a. Then, with the washer 60 fitted to the large-diameter portion 50 b of the through hole 50, the bolt member 56 is inserted from the one flange portion 46 side, and the distal end portion of the male screw 56 b of the bolt member 56 protrudes from the flange portion 47. Then, the nut member 73 is screwed to the protruding portion.

  Therefore, even in the coupling structure M shown in FIG. 11, if the bolt member 56 is screwed with respect to the nut member 73, the one flange portion 46 and the other flange portion 47 approach each other. . As a result, the diameter of the boss 45 is reduced, the female serration 48 and the male serration 49 are brought into close contact with each other, and the shaft 31 is coupled to the boss 45 without play.

  Thus, when the nut member 73 is used, it is not necessary to provide the screw hole 52 in the flange portion 47 shown in FIGS. 1 to 6 and the like, and the workability can be improved. However, as shown in FIG. 3 and the like, in the case where the flange portion 47 is provided with the internal thread portion (screw hole) 52 into which the bolt member 56 of the bolt structure 55 is screwed, it is not necessary to use a nut member, and the number of parts is reduced. Therefore, it is possible to improve the assemblability and reduce the cost.

  In FIG. 12, a fixed type constant velocity universal joint is used as the universal joint. The fixed type constant velocity universal joint is a Rzeppa joint (BJ), an outer ring 81 as an outer joint member having a plurality of track grooves 80 formed on the inner peripheral surface, and an inner joint member having a plurality of track grooves 82 formed on the outer peripheral surface. As an inner ring 83, a plurality of balls 84 arranged on a ball track formed in cooperation with the track groove 80 of the outer ring 81 and the track groove 82 of the inner ring 83, and a holder 85 for holding the ball 84. The main part is composed. A female spline 86 is formed on the inner periphery of the inner ring 83, and a male spline 87 provided at the end of the shaft 31 is fitted to the female spline 86.

  In this fixed type constant velocity universal joint, a plunger unit 90 is attached to the shaft end of the shaft 31. The plunger unit 90 is an assembly body including a pressing portion 91 formed of a ball member, an elastic member (not shown) that presses the pressing portion, and a case 94 that houses the elastic member.

  In addition, a receiving member 95 is attached to the rear end of the outer ring 81 of the cage 85. The receiving member 95 has a lid shape covering the end opening of the cage 85, and includes a spherical portion 95a having a partially spherical shape and an attachment portion 95b formed in an annular shape on the outer periphery thereof. The inner surface (the surface facing the shaft) of the spherical portion 95a is a concave spherical surface, and this concave spherical surface functions as a receiving portion 92 that receives the pressing force from the pressing portion 91. The attachment portion 95b is fixed to the end portion of the cage 85 by appropriate means such as press fitting and welding.

  The pressing portion 91 of the plunger unit 90 and the receiving portion 92 of the receiving member 95 come into contact with each other, the pressing portion 91 retreats into the case, and the compression coil spring (not shown) is compressed. As a result, the inner ring 83 integrated with the shaft 31 is displaced in the axial direction toward the opening side of the outer ring 81 due to the elastic force, and the ball 84 and the track grooves 80, 82 arranged in the track grooves 80, 82 are displaced by this displacement. As a result, the axial clearance of the track grooves 80 and 82 is eliminated, and rotational backlash is prevented. Therefore, the plunger unit 90 and the receiving member 95 constitute a backlash filling mechanism M1 that closes the gap between the track grooves 80 and 82 and the ball 84.

  The outer ring 81 of the constant velocity universal joint includes a mouse part 81a and a shaft part 81b protruding from the bottom wall of the mouse part 81a. The shaft part 81b is a boss part of the coupling structure M according to the present invention. 45 is configured. Since the coupling structure in this case is the same as the coupling structure shown in FIG. 1, the same reference numerals as those in FIG. For this reason, the shaft 31 can be stably coupled to the outer ring 81 of the constant velocity universal joint via the coupling structure M according to the present invention.

FIG. 13 shows an embodiment applied to a double cardan joint. As is well known, the cardan joint is an inconstant velocity joint, and therefore, when used in a steering device, the steering feeling may be adversely affected. Therefore, in order to eliminate this problem, a double cardan joint uses two cardan joints 30 as a set.

  Thus, the coupling structure M according to the present invention may be a cardan type universal joint as shown in FIG. 1 or a fixed type constant velocity universal joint as shown in FIG. 12 may be used, and can be applied to various universal joints. The cardan type universal joint has a simple structure, but if the cardan joint alone has a crossing angle between the two axes, it is inevitable that the speed is mechanically inconstant. Therefore, if a double cardan universal joint obtained by combining two cardan universal joints is used, rotational fluctuations of the cardan universal joint can be offset, and constant velocity can be ensured.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in each of the above-described embodiments, the fitting hole 59 has one flange. The through hole 50 provided in the portion 46 and the hole portion 51 of the other flange portion 47 are configured. However, when the cylindrical body 54 is fitted and engaged with the circumferential groove 57 of the shaft 31 and the shaft 31 can be positioned, the fitting hole 59 is a through-hole provided in one flange portion 46. You may make it comprise only 50. Further, in the coupling structure M shown in FIG. 1 and the like, even if the axial length of the screw hole 52 provided in the flange portion 47 is the male screw 56b of the bolt member 56, the flange portions 46 and 47 can be tightened. If so, various changes can be made.

  Moreover, although the cylindrical body 54 was comprised with the cylindrical body, the polygon surface which the outer diameter surface is not a cylindrical surface may be sufficient. For this reason, the cross-sectional shape of the bottom surface of the circumferential groove 57 of the shaft 31 is not limited to the circular arc surface. In the coupling structure M shown in FIGS. 10, 11, 12, and 13, a washer may not be used.

  When a fixed type constant velocity universal joint as shown in FIG. 12 is used for the universal joint, even if the track groove bottom surface is composed of a single arc portion, the track groove bottom surface is An undercut free type consisting of a straight portion may be used.

30 Universal joint 31 Shaft 32 Yoke 46, 47 Flange 50 Through hole 52 Screw hole 53 Clearance 55 Bolt structure 56 Bolt member 60 Washer 62 Slit 63 Tapered surface 73 Nut member 80, 82 Track groove 81 Outer joint member (outer ring)
83 Inner joint member (inner ring)
84 Ball 85 Cage

Claims (14)

In a state where the end of the shaft is inserted into the boss of the yoke provided in the universal joint, the boss is contracted by tightening a bolt structure attached to a pair of flanges extending in the outer diameter direction from the boss. A coupling structure for connecting the shaft and the yoke with a diameter;
A cylindrical body to be locked to the end of the shaft inserted into the boss part is fitted into a fitting hole provided in the flange part, and a bolt member having the bolt structure is inserted into the cylindrical body. Bonding structure characterized by tightening by structure.   The coupling structure according to claim 1, wherein a slit extending in the axial direction is provided on a peripheral wall of the cylindrical body, and the cylindrical body is press-fitted into a fitting hole provided in the flange portion.   The coupling structure according to claim 2, wherein the cylindrical body is provided with a tapered surface whose diameter decreases toward the press-fitting start end at a press-fitting start end of the outer peripheral surface.   The coupling structure according to claim 2 or 3, wherein the cylindrical body is made of resin.   The joint structure according to any one of claims 1 to 4, wherein a seat surface of a bolt member having a bolt structure directly contacts a seat surface of the fitting hole.   The coupling structure according to any one of claims 1 to 4, wherein a washer is interposed between a seating surface of a bolt member having a bolt structure and a seating surface of the fitting hole. .   The coupling structure according to claim 5 or 6, wherein a gap is provided between a seat surface of a bolt structure made of a seat surface of a bolt member or a washer and the cylindrical body.   8. The coupling structure according to claim 1, wherein the bolt member of the bolt structure is screwed into a nut member which is a separate member from the flange portion.   A bolt member having a bolt structure is inserted into one flange portion to provide a through hole constituting the fitting hole, and a female screw portion into which the bolt member is screwed is provided in the other flange portion. The coupling structure according to any one of claims 1 to 7.   The universal joint includes an outer joint member having a plurality of track grooves formed on an inner diameter surface, an inner joint member having a plurality of track grooves formed on an outer diameter surface, and a track groove and an inner joint member of the outer joint member. A plurality of torque transmitting balls as torque transmitting members that are interposed between the track grooves and transmit torque, and are interposed between the inner diameter surface of the outer joint member and the outer diameter surface of the inner joint member to hold the balls. 10. A fixed type constant velocity universal joint including a cage for holding, and a backlash filling mechanism for filling a gap between the track groove and the ball. Bonding structure described in 1.   The coupling structure according to claim 10, wherein the fixed type constant velocity universal joint is a track offset type in which a bottom surface of a track groove is configured by a single arc portion.   The coupling structure according to claim 10, wherein the fixed type constant velocity universal joint is an undercut free type in which a bottom surface of a track groove includes an arc portion and a straight portion.   The coupling structure according to any one of claims 1 to 9, wherein the universal joint is a double cardan universal joint.   A steering apparatus using the coupling structure according to any one of claims 1 to 13.

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