JP2006300085A - Joint part of shaft and yoke - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure manufacturable at rather low cost and capable of accurately positioning a yoke 24 and a steering shaft 23 in their respective directions. <P>SOLUTION: First and second recessed parts 50 and 51 are formed in the tip part outer peripheral surface of a steering shaft 23. A nut 26 is installed on a retaining plate part 29 forming the base end part 28 of the yoke 24 while imparting an elastic force in the direction projected from a retaining surface 31. The steering shaft 23 is pushed to the bottom of the base end part 28 only when the tip part of the nut 26 matches the second recessed part 51. When the steering shaft is pushed, the tip part of the nut 26 is engaged with the first recessed part 50 to prevent the position of the steering shaft 23 from being displaced from the position of the yoke 24. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improvement in a joint portion between a shaft and a yoke, which is used to join end portions of various shafts constituting the steering device and a yoke of a universal joint in a steering device for an automobile, for example.

  Patent Document 1 describes a structure of a coupling portion between a shaft and a universal joint yoke as shown in FIG. The structure shown in FIG. 16 is a part of a steering device for imparting a steering angle to the front wheels of an automobile, and the movement of the steering shaft that rotates as the steering wheel is operated is 1 is incorporated into a portion that transmits to the input shaft of the steering gear. The universal joint 1 is formed by connecting a pair of yokes 2 and 3 via a cross shaft 4. The four end portions provided on the cross shaft 4 are swingably supported on the tip portions of the yokes 2 and 3 via needle bearings provided in the bearing cups 5 and 5, respectively. . Therefore, even if the centers of the yokes 2 and 3 are not located on the same straight line, the rotational force can be transmitted between the yokes 2 and 3.

  When the steering device is assembled using such a universal joint 1, for example, one yoke 2 (right side in FIG. 16) is attached to the end of one shaft 6 such as a steering shaft by welding or screwing in advance. The other yoke 3 (left side in FIG. 16) is coupled to the end of the other shaft 7. In order to perform such assembling work, usually, the one shaft 6 is supported on the vehicle body, and then the shaft 6 and the other shaft 7 are coupled by the universal joint 1.

  Therefore, among the yokes 2 and 3 of the universal joint 1 constituting the steering device, at least the other yoke 3 is preferably a so-called lateral insertion type in which connection work can be performed without moving the shaft 6 in the axial direction. For example, in the case of the universal joint 1 shown in FIG. 16, one yoke 2 is fixed by welding to the end of one shaft 6, while the other yoke 3 has a U-shaped cross section as shown in FIG. It is a horizontal type having a base end portion 8.

  The base end portion 8 of the horizontal insertion type yoke 3 includes a pair of holding plate portions 9a and 9b. These holding plate portions 9a and 9b that are arranged apart from each other have the inner side surfaces as holding surfaces 10 and 10 that are parallel to each other. Then, a screw hole 12 is provided by internally fitting and fixing a nut 11 to the opening side end of one (left side in FIG. 17) holding plate portion 9a. In addition, a through hole 13 concentric with the screw hole 12 and having a diameter larger than that of the screw hole 12 is formed at the opening side end of the other holding plate 9b.

  On the other hand, the shaft 7 that joins the tip portion of the yoke 3 configured as described above has at least the cross-sectional shape of the tip portion as an oval shape as shown in FIG. That is, a pair of outer flat surfaces 14 and 14 parallel to each other are formed on the outer peripheral surface of the distal end portion of the shaft 7, and the outer flat surfaces 14 and 14 and the holding surfaces 10 and 10 are brought into close contact with each other at the time of connection. The rotation of the shaft 7 with respect to the yoke 3 is prevented.

  When the end portion of the shaft 7 having the shape as described above is connected and fixed to the base end portion 8 of the yoke 3 as described above, first, as shown by the solid line in FIG. It arrange | positions at the opening side of the said base end part 8. FIG. From this state, for example, by turning the yoke 3 about the cross shaft 4, the yoke 3 is swung clockwise from the solid line state to the chain line state in FIG. The end of the shaft 7 is inserted into the base end 8 of the yoke 3. Note that the end of the shaft 7 may be inserted into the base end 8 of the yoke 3 by moving the end of the shaft 7 without moving the yoke 3. In any case, before the end portion of the shaft 7 is inserted into the base end portion 8, no holding bolt (not shown) is inserted into the through hole 13.

  If the end portion of the shaft 7 is inserted into the base end portion 8 of the yoke 3 as described above and the respective restraining surfaces 10 and 10 are opposed to the outer flat surfaces 14 and 14 (FIGS. 17 to 18), The male screw portion formed at the tip of the holding bolt inserted through the through hole 13 is screwed into the screw hole 12 and further tightened. Based on this tightening, the distance between the pair of restraining surfaces 10 and 10 is narrowed, the restraining surfaces 10 and 10 and the outer flat surfaces 14 and 14 are in strong contact, and the tip of the shaft 7 is The base end 8 is coupled and fixed. In addition, while forming the recessed part 15 in the edge part edge part of the said shaft 7, while preventing the interference with this shaft 7 and the collar part of the said restraining bolt, even when this restraining bolt loosens, The yoke 3 is prevented from coming off in the axial direction of the shaft 7.

  In the case of the structure described in Patent Document 1 as described above, it is not particularly intended to improve the efficiency of the connecting operation between the yoke 3 and the shaft 7. Therefore, this joining work in a limited space can be troublesome. That is, this joining work needs to be performed with the operator's hand inserted in a limited space such as in the engine room of a car. While maintaining the relationship, the holding bolt and the nut 11 must be screwed together and further tightened. On the other hand, after the distal end portion of the shaft 7 is inserted into the proximal end portion 8 of the yoke 3, the distal end portion of the shaft 7 is not attached to the proximal end portion 8 in a state where the retaining bolt is not yet assembled. It is easy to drop off from the base end portion 8. Further, if the mounting positions of the shaft 7 and the yoke 3 in the axial direction are not appropriate, there is a possibility that the assembled steering device cannot exhibit its original performance.

  On the other hand, in Patent Document 2, only when the phase of the protruding piece formed on the cover member made of a metal plate attached to the base end portion of the yoke and the groove portion formed on the side surface of the tip end portion of the shaft is matched, A structure is described in which the distal end portion of the shaft can be inserted into the proximal end portion of the yoke. Patent Documents 3 and 4 describe a structure for preventing the distal end portion from inadvertently coming out of the proximal end portion after the shaft distal end portion is once inserted into the proximal end portion of the yoke. ing. However, in the case of the structure described in Patent Document 2, not only the processing of the cover member and the assembly to the shaft is troublesome, but the cost is increased, and the positioning of the cover member with respect to the shaft and the extension of the shaft are not limited. There is a possibility that the positioning with the yoke cannot always be performed accurately. In the case of the structures described in Patent Documents 3 and 4, positioning in the axial direction between the shaft and the yoke is not considered.

Japanese Patent Laid-Open No. 10-9281 JP 2004-150583 A Japanese Patent No. 2735260 US Pat. No. 5,090,833

  The present invention has been invented to realize a structure that can be manufactured at a relatively low cost and that can accurately position the yoke and the shaft in each direction in view of the above-described circumstances.

The joint portion between the shaft and the yoke of the present invention is the same as the conventional joint portion between the shaft and the yoke, and the shaft that rotates during use, the yoke that constitutes the joint, the shaft and the yoke, A holding bolt and a nut are provided.
Of these, the shaft forms a pair of outer flat surfaces on the outer peripheral surface of the tip.
The yoke has a base end portion that is open on the side. The base end portions are spaced apart from each other and each pair of inner side surfaces serves as a pair of restraining surfaces facing the outer side flat surfaces. The holding plate formed on the holding plate portion, the connecting portion that connects these holding plate portions to each other at the portion opposite to the opening of the base end portion, and the holding plate portion that is one of the holding plate portions. And a through hole through which the head of the restraint bolt can be passed. Further, the nut is assembled to the other of the holding plate portions.
And in the state which inserted the front-end | tip part of the said shaft between both said control board parts, by screwing the male thread part of the said control bolt which penetrated the said through hole to the said nut, the both said control board parts are carried out. The holding surface is pressed against the both outer planes.

In particular, in the joint portion between the shaft and the yoke of the present invention, the nut is more distal than the step surface formed on the outer peripheral surface of the axially intermediate portion so as to face the outer surface of the other holding plate portion. Displace the displacement part in the direction of the central axis of the mounting hole and swing around the central axis inside the circular mounting hole formed concentrically with the through hole in a part of the other holding plate part. While being able to be fitted, the elasticity of the direction which makes a front-end | tip part protrude from the control surface of the said other control board part is provided.
Also, the position of the shaft in the axial direction is a part of the outer peripheral surface of the tip end portion of the shaft that faces the surface opposite to the connecting portion and the restraining surface of the other restraining plate portion. Thus, first and second recesses having a width dimension in the axial direction larger than a width dimension in the same direction of the tip edge portion of the nut are formed in a portion to be aligned with the through hole and the mounting hole.
In addition, an inclined surface that is inclined in a direction closer to the one holding plate portion as the closer to the connecting portion is formed in a portion opposite to the connecting portion of the tip portion of the nut.
Furthermore, the amount of displacement by which the tip of the nut is displaced in the direction of retreating from the tip of the shaft is limited. And only when the tip edge of the nut and the second recess formed on the surface of the tip outer peripheral surface of the shaft facing the holding surface of the other holding plate are aligned, the shaft The tip end portion of the nut is moved to the connecting portion side with respect to the tip end edge portion of the nut, and the tip end edge portion of the nut and the first recess are engaged.

  The coupling portion between the shaft and the yoke of the present invention configured as described above acts as follows to regulate the positional relationship between these two members so that the shaft and the yoke are combined in a regular positional relationship. . And after being combined, these two members are prevented from being inadvertently separated or from shifting their positional relationship.

  First, the front end portion of the shaft is opposed to the side opening of the base end portion of the yoke in a state where the both outer planes and the restraining surfaces of both restraining plate portions are parallel to each other. Then, from this state, the tip of the shaft is pushed between the holding plate portions. Along with this pushing, a part of the outer peripheral surface of the tip of the shaft engages with the inclined surface of the nut, and the nut is retracted in a direction away from one holding plate portion constituting the yoke. As a result, the space between the leading edge of these nuts and the restraining surface of one restraining plate portion is widened, and the distal end portion of the shaft can be pushed further into the proximal end portion.

  However, the amount of displacement of the nut in the retracting direction is limited, and the tip edge of the nut is not completely retracted from the restraining surface of the other restraining plate (does not protrude from the restraining surface). On the other hand, the distance between the two outer planes formed at the distal end portion of the shaft (the width dimension of the distal end portion of the shaft) is between the restraining surfaces of the pair of restraining plate portions constituting the base end portion of the yoke. It is only slightly smaller than the distance (the inner dimension of the base end of this yoke). In the state in which the nut is retracted most, the distance between the leading edge of the nut and the restraining surface of the one restraining plate is such that the bottom surface of the second recess and the outer side opposite to the second recess. It is larger than the distance from the plane. Therefore, the distal end portion of the shaft is located deeper in the base end portion of the yoke than the distal end edge portion of the nut, that is, the connecting portion only when the distal end edge portion of the nut and the second recessed portion are aligned. Move to the side. Then, in the state where the tip of the shaft has moved all the way to the back of the yoke, the protruding amount of the tip of the nut from the restraining surface of the other restraining plate increases, and the tip edge of the nut And the first recess formed at the tip of the shaft engages.

  In this state, the shaft and the yoke are combined in a regular positional relationship, and both the members are prevented from being inadvertently separated or moved from each other. That is, the shaft is prevented from being displaced in the axial direction with respect to the yoke based on the engagement between the front end edge of the nut and the first recess. Further, as the protruding amount of the tip of the nut from the restraining surface of the other restraining plate increases, the interval between the leading edge of the nut and the restraining surface of the one restraining plate is It becomes smaller than the space | interval of the bottom face of said 2nd recessed part, and the outer side plane on the opposite side to this 2nd recessed part. As a result, the shaft does not move in the axial direction relative to the base end portion of the yoke, and does not come out of the base end portion.

In the case of carrying out the present invention, preferably, as described in claim 2, a portion of the front end portion of the nut facing the connecting portion is rotated with the rotation of the nut, and the outer peripheral surface of the front end portion of the shaft. Based on the engagement with the bottom surface of the first recess formed on the surface opposite to the connecting portion, a cam portion is formed that presses the tip of the shaft toward the connecting portion. Further, a resistance portion for increasing the sliding resistance of the threaded portion between the female screw and the male screw is provided at a part of the threaded portion between the female screw formed on the nut and the male screw formed on the holding bolt.
If comprised in this way, the said nut will rock | fluctuate with a big torque with rotation of the said holding | suppressing volt | bolt, and the front-end | tip part of the said shaft is pressed toward the said connection part by the said cam part. As a result, the posture of the tip end portion of the shaft is corrected following the inner surface of the connecting portion, and the central axis of the shaft and the central axis of the yoke can be matched.

Preferably, when the present invention is carried out, the stepped surface is preferably one side surface in the axial direction of the flange portion of the outward flange provided on the outer circumferential surface of the axially intermediate portion of the nut. . And, the spring provided between the inner surface of the cover fixed to the outer side surface of the other pressing plate portion and the other axial side surface of the flange portion causes the tip end portion of the nut to be pressed to the holding surface of the other pressing plate portion. Gives elasticity in the direction of projecting from.
If comprised in this way, the elasticity of the direction which makes a front-end | tip part protrude from the control surface of said other control board part can be provided with respect to the said nut with a comparatively simple structure.

Further, when carrying out the invention described in claim 3 as described above, preferably, as described in claim 4, the nut is disposed on the inner side of the through-hole formed in the cover. The axial displacement of is inserted through. Then, based on the engagement between the peripheral portion of the through hole on the inner surface of the cover and the engaging step surface formed at the axially intermediate portion of the nut, the tip of the nut is retracted from the tip of the shaft. Limit the amount of displacement.
If comprised in this way, the retraction | saving amount of the front-end | tip part of the said nut can be controlled appropriately with a comparatively simple structure.

When the present invention is carried out, preferably, as described in claim 5, the first and second recesses are formed at two positions on the opposite side in the diameter direction of the tip of the shaft.
If comprised in this way, the freedom degree of the insertion direction of the front-end | tip part of the said shaft with respect to the base end part of a yoke will improve (it may become 180 degree opposite side). For this reason, it is possible to further facilitate the connecting operation between the shaft and the yoke performed in a narrow engine room or the like.

  FIGS. 1-11 has shown Example 1 of this invention corresponding to Claims 1-4. First, FIG. 1 shows a rotation transmission device for a steering device in which a coupling portion between a shaft and a yoke according to the present invention is incorporated. In this rotation transmission device, both ends of an intermediate shaft 19 in which the outer shaft 16 and the inner shaft 17 are combined with a spline engaging portion 18 so that the entire length thereof can be expanded and contracted are connected to another steering shaft 22, 23. Among these, the joint part of the yoke 24 and the steering shaft 23 which comprise the universal joint 21 described in the lower left of FIG. 1 has the structure of this invention. The connection structure related to the universal joint 20 at the upper right is an axial insertion type that is not related to the present invention.

  In the case of the rotation transmission device for a steering device as shown in FIG. 1 described above, the position of the lower left universal joint 21 becomes unstable as the intermediate shaft 19 expands and contracts. In other words, the degree of freedom of the position of the yoke 24 constituting the universal joint 21 is increased. For this reason, the fitting length between the yoke 24 and the steering shaft 23 in the axial direction of the steering shaft 23 tends to be unstable. And when this fitting length becomes shorter than a prescribed value, the coupling strength between the yoke 24 and the steering shaft 23 may be insufficient. On the other hand, when the fitting length is longer than the specified value, the end of the steering shaft 23 interferes with the cross shaft or the like constituting the universal joint 21, and the universal joint 21. May malfunction. For this reason, in the past, the yoke 24 and the steering shaft 23 were combined while performing sufficient confirmation work to make the fitting length the specified value. However, the confirmation work was performed in a narrow engine room. It was cumbersome to do. The present embodiment is intended to eliminate the confirmation work by applying the present invention to the joint portion between the yoke 24 and the steering shaft 23. Hereinafter, the connecting portion will be described in detail.

As shown in FIGS. 2 to 4, the coupling portion is the shaft described in the claims, the steering shaft 23, the yoke 24, and a holding bolt 25 that couples the steering shaft 23 and the yoke 24. And a nut 26.
As shown in FIGS. 1 to 5, 10, and 11, the steering shaft 23 includes a pair of outer flat surfaces 27 and 27 that are parallel to each other at two positions on the outer peripheral surface of the tip portion on the diametrically opposite side. Thus, the cross-sectional shape of the tip is an oval shape.

  The yoke 24 has a base end portion 28 that is open on the side. The cross-sectional shape of the base end portion 28 is U-shaped, and includes a pair of holding plate portions 29 a and 29 b and a connecting portion 30. Both of the holding plate portions 29a and 29b are flat and spaced apart from each other and are arranged substantially parallel to each other. The inner side surfaces of the holding plate portions 29a and 29b are set as the holding surfaces 31 and 31 facing the respective outer flat surfaces 27 and 27. Yes. The connecting portion 30 has an arc shape in cross section, and connects one end edges in the width direction of the holding plate portions 29a and 29b to each other at a portion opposite to the opening of the base end portion 28. In addition, a circular through hole 32 is formed in one of the holding plate portions 29a and 29b (upward in FIG. 3, left in FIGS. 4, 5, 10, and 11). The inner diameter of the through hole 32 is such that the flange 33 of the holding bolt 25 can be inserted, but the head 34 of the holding bolt 25 is not allowed to pass through. Further, the nut 26 is assembled to the other pressing plate portion 29b (lower side in FIG. 3, right side in FIGS. 4, 5, 10, and 11) of the holding plate portions 29a and 29b.

  As shown in FIG. 4, the male screw portion 35 of the holding bolt 25 inserted through the through hole 32 is inserted with the tip end portion of the steering shaft 23 inserted between the holding plate portions 29 a and 29 b. The nut 26 is screwed. Further, by reducing the spacing between the two restraining plate portions 29a and 29 based on the tightening of the restraining bolt 25, the restraining surfaces 31 and 31 of the two restraining plate portions 29a and 29b are formed on the both outer flat surfaces 27 and 27. The steering shaft 23 and the yoke 24 are coupled and fixed by pressing and frictional engagement between the surfaces 31 and 27.

  In the case of the present embodiment, the nut 26 is formed in a substantially cylindrical shape as a whole, and an outward flange-shaped flange portion 36 is formed on the outer peripheral surface in the axial direction intermediate portion. A circular mounting hole 37 concentric with the through hole 32 is formed in a part of the other holding plate portion 29b. And the front-end | tip part (FIG. 4, 5) which protruded from the one side surface (left side surface of FIG. 4, 5, 6, 10, 11) of the said collar part 36 which is the level | step difference surface described in Claim 1. , 6, 10, and 11) are fitted into the mounting hole 37 by gap fitting. Therefore, the nut 26 can be displaced in the direction of the central axis of the mounting hole 37 (the left-right direction in FIGS. 4, 5, 10, and 11) and swing around the central axis on the other holding plate portion 29b. It is supported by.

  A cover 38 is fixed to the outer surface of the other holding plate 29b. The cover 38 is formed by subjecting a metal plate such as a stainless steel plate to plastic processing such as drawing, and includes a cylindrical main portion 39. At the edge of the main portion 39 in the axial direction (the right end in FIGS. 4, 5, 10, and 11), an inward flange portion 40 that is bent radially inward is provided over the entire circumference. In addition, outward flanges 41a, 41b, 41c bent outward in the radial direction are intermittently provided in the circumferential direction at the other axial end of the main portion 39 (the left end in FIGS. 4, 5, 10, and 11). Provided. In addition, L-shaped leg pieces 42 and 42 are provided between the outward flanges 41a, 41b and 41c adjacent to each other in the circumferential direction at a part of the other axial end edge of the main portion 39 in the axial direction. It is formed so as to protrude in the axial direction from the other end edge. These leg pieces 42 and 42 are inserted into the recessed holes 43 and 43 formed at a plurality of locations (three locations in the illustrated embodiment) on the outer surface of the other holding plate portion 29b. The opening edge portions of the holes 43 and 43 are caulked toward the bent portions of the leg pieces 42 and 42. With such a structure, the cover 38 is fixed at a position surrounding the opening of the mounting hole 37 on the outer surface of the other holding plate 29b.

  In this way, the inward flange portion 40 formed on one end edge in the axial direction of the cover 38 fixed to the outer surface of the other holding plate portion 29b, and the flange formed on the outer peripheral surface in the axial direction intermediate portion of the nut 26. A compression coil spring 44 is provided between the other side surface of the portion 36 (the right side surface in FIGS. 4, 5, 6, 10, and 11). The compression coil spring 44 imparts elasticity to the nut 26 in a direction in which the tip of the nut 26 protrudes from the restraining surface 31 of the other restraining plate 29b.

  Further, the base end portion of the nut 26 (the right end portion in FIGS. 4, 5, 10, and 11) is disposed inside the through hole 45 formed in the inner diameter side portion of the inward flange portion 40 of the cover 38. Axial displacement is possible. As shown in FIG. 2, the shape of the through-hole 45 is a shape in which a circular part is recessed to make the part a straight edge 46. Further, the outer peripheral surface of the base end portion of the nut 26 has a shape in which a part of the cylindrical surface is recessed inward in the radial direction to form a flat surface 47. The diameter of the arc-shaped portion in the through hole 45 is slightly larger than the diameter of the cylindrical portion in the outer peripheral surface of the base end portion of the nut 26. On the other hand, the difference in distance from each center to the straight edge 46 or the flat surface 47 is larger than the difference between the two diameters. Therefore, in a state where the straight edge 46 and the flat surface 47 are parallel to each other, a gap corresponding to the width dimension S shown in FIG. 2 is generated between the straight edge 46 and the flat surface 47. The nut 26 can swing by the amount of S relative to the yoke 24 to which the cover 38 is fixed.

  Further, an engagement step surface 48 formed along with the formation of the flat surface 47 exists in a portion near the base end of the outer peripheral surface of the intermediate portion of the nut 26. The engagement step surface 48 is opposed to the inner surface of the portion corresponding to the linear edge 46 in the inward flange portion 40 of the cover 38. The amount of displacement of the nut 26 in the direction of retreating from the tip of the steering shaft 23 inserted in the yoke 24 is limited to m shown in FIG. As shown in FIG. 5, the upper limit value m of the amount of displacement is the other restraining plate in a state where one side surface of the flange portion 36 is in contact with the outer surface of the other restraining plate portion 29b. The protrusion amount M of the nut 26 from the holding surface 31 of the portion 29b is smaller than the protruding amount M (M> m).

  Further, in the tip portion of the nut 26, the connecting portion is located at a portion located on the side opposite to the connecting portion 30 (opening side of the base end portion 28) in the assembled state with the base end portion 28 of the yoke 24. An inclined surface 49 is formed which is inclined in a direction approaching the one holding plate portion 29a as it approaches 30. The inclined surface 49 is formed between the distal end surface radial direction intermediate portion of the nut 26 and the axial direction intermediate portion distal end portion. Of these, as shown in FIG. 5, the axially middle portion of the tip end portion is separated from the restraining surface 31 even when the tip end portion of the nut 26 protrudes most from the restraining surface 31 of the other restraining plate portion 29b. It exists in a position that does not protrude.

On the other hand, first and second recesses 50 and 51 are formed on two surfaces adjacent to each other in the circumferential direction in the outer peripheral surface of the tip end portion of the steering shaft 23. Of these, the first concave portion 50 is disposed on the surface on the opposite side of the connecting portion 30 in the assembled state of the outer peripheral surface of the distal end portion of the steering shaft 23 to the base end portion 28 of the yoke 24. It is formed so as to cross in the width direction. On the other hand, the second recess 51 is a part of the surface facing the restraining surface 31 of the other restraining plate 29b, and the position of the steering shaft 23 in the axial direction is the same as that of the first recess 50. They are formed at portions that match and that should be aligned with the through holes 32 and the mounting holes 37 formed in the two holding plate portions 29a and 29b in the assembled state. In addition, a continuous recess 52 inclined approximately 45 degrees with respect to the bottom surfaces of the first and second recesses 50 and 51 is formed between the first and second recesses 50 and 51. The first and second recesses 50 and 51 are connected relatively smoothly. The width dimensions W ₅₀ , W _{51 of} the first and second recesses 50, 51 in the axial direction of the steering shaft 23 (and the width dimension of the continuous recess 52, see FIG. 9) are the leading edges of the nut 26. It is slightly larger (for example, about 0.5 to 2 mm) than the width dimension W ₂₆ (refer to FIG. 8) in the same direction of the part (W ₅₀ ≈W ₅₁ > W ₂₆ ).

  The depth N of the second recess 51 (see FIG. 10) is such that the distal end portion of the steering shaft 23 can be inserted into the base end portion 28 of the yoke 24 while the nut 26 is pushed away. The front end of the nut 26 is regulated in relation to the amount of displacement that is displaced in the direction of retreating from the front end of the steering shaft 23. And only in the state where the tip edge of the nut 26 and the second recess 51 are aligned, the tip of the steering shaft 23 is moved to the connecting part 30 side from the tip edge of the nut 26, The front end edge of the nut 26 and the first recess 50 are configured to engage with each other. Therefore, the depth of the first recess 50 is regulated to such a depth that the front end edge of the nut 26 and the first recess 50 can be engaged with each other.

  Further, a cam portion 53 is formed in a portion of the tip end portion of the nut 26 facing the connecting portion 30 in the assembled state with the yoke 24. In the case of the present embodiment, in order to form the cam portion 53, a portion of the outer peripheral surface of the nut 26 opposite to the connecting portion 30 is parallel to the connecting portion 30 in a neutral state. The flat surface 54 is formed. The distance from the rotation center of the nut 26 is short at the center of the flat surface 54 and long at both ends of the flat surface 54 with respect to the rotation direction of the nut 26. Further, with the distal end portion of the steering shaft 23 inserted to the back of the base end portion 28 of the yoke 24 and the first concave portion 50 and the flat surface 54 being in parallel, the first concave portion 50. The bottom surface and the flat surface 54 abut or face each other. When the nut 26 is rotated from this state, the cam portion 53, which is the end portion of the flat surface 54, engages with the bottom surface of the first recess 50, and the tip end portion of the steering shaft 23 is engaged. Is pressed toward the connecting portion 30. At this time, in order to increase the force with which the cam portion 53 presses the bottom surface of the first recess 50, the threaded portion of the female screw 55 formed on the nut 26 and the male screw 56 formed on the holding bolt 25 is provided. A part is provided with a resistance portion for increasing the sliding resistance of the threaded portion between the female screw 55 and the male screw 56. In the case of the present embodiment, as shown in FIGS. 5 to 7, a caulking portion 57 formed by plastically deforming a plurality of circumferential locations (three locations in the illustrated example) of the opening end of the female screw 55 radially inward. , 57 constitute the resistance portion.

  In order to assemble the structure of the present embodiment configured as described above, first, as shown by a chain line in FIG. 5, the distal end portion of the steering shaft 23 is inserted into the side opening of the proximal end portion 28 of the yoke 24. Both the outer flat surfaces 27, 27 and the restraining surfaces 31, 31 of the restraining plate portions 29a, 29b are opposed to each other in a substantially parallel state. From this state, as shown in FIG. 10, the tip end portion of the steering shaft 23 is pushed between the holding plate portions 29a and 29b. Along with this pushing, a part of the outer peripheral surface of the front end portion of the steering shaft 23 engages with the inclined surface 49 formed on the front end surface of the nut 26, and this nut 26 constitutes the yoke 24. Is retracted in a direction away from the holding plate portion 29a (to the right in FIG. 10). As a result, as shown in FIG. 10, the distance between the leading edge of the nut 26 and the restraining surface 31 of the one restraining plate 29a is widened, and the distal end of the steering shaft 23 can be pushed further into the base end 28. It becomes like.

  However, the amount of displacement of the nut 26 in the retracting direction is limited by the engagement between the inward flange portion 40 of the cover 38 and the engagement step surface 48, and the leading edge of the nut 26 is the other holding plate. There is no possibility of being completely retracted from the restraining surface 31 of the portion 29b (no longer protruding from the restraining surface 31). More specifically, the amount of protrusion of the leading edge of the nut 26 from the restraining surface 31 of the other restraining plate portion 29b is the distance between the inner surfaces of the restraining plate portions 29a and 29b (in a free state). And the thickness δ (see FIG. 10) of the gap generated based on the difference between the width of the front end portion of the steering shaft 23 and the width dimension of the steering shaft 23. On the other hand, the distance between the outer flat surfaces 27, 27 formed at the distal end portion of the steering shaft 23 (the width dimension of the distal end portion of the steering shaft 23) is a pair constituting the proximal end portion 28 of the yoke 24. It is only slightly smaller (the above-mentioned δ) than the space between the restraining surfaces 31, 31 of the restraining plate portions 29a, 29b (the inner dimension of the base end portion 28 of the yoke 24). On the other hand, in the state where the nut 26 is most retracted, the distance between the leading edge of the nut 26 and the restraining surface 31 of the one restraining plate portion 29a is the same as the bottom surface of the second recess 51 and the first. It is larger than the distance between the second recess 51 and the outer flat surface 27 on the opposite side. Accordingly, the distal end portion of the steering shaft 23 is located at the base end portion 28 of the yoke 24 more than the distal end edge portion of the nut 26 only when the distal end edge portion of the nut 26 and the second recess 51 are aligned. It moves to the back, ie, the connection part 30 side. Then, with the tip of the steering shaft 23 moved to the back of the yoke 24, as shown in FIG. 11, the tip of the nut 26 protrudes from the restraining surface 31 of the other restraining plate 29b. The amount increases, and the leading edge of the nut 26 engages with the first recess 50 formed at the leading end of the steering shaft 23.

  In this state, the steering shaft 23 and the yoke 24 are combined in a proper positional relationship, and both the members 23 and 24 are prevented from being inadvertently separated or displaced from each other. . That is, the steering shaft 23 is prevented from being displaced in the axial direction with respect to the yoke 24 based on the engagement between the front end edge of the nut 26 and the first recess 50. Further, in this state, the protruding amount of the tip end portion of the nut 26 from the restraining surface 31 of the other restraining plate portion 29b is increased, and the leading edge of the nut 26 and the restraining surface of the one restraining plate portion 29a are increased. The distance to 31 is smaller than the distance between the bottom surface of the second recess 51 and the outer flat surface 27 opposite to the second recess 51. As a result, the steering shaft 23 does not move in the axial direction with respect to the base end portion 28 of the yoke 24 and does not come out of the base end portion 28. In this way, the operation of combining the steering shaft 23 and the base end portion 28 of the yoke 24 in a normal positional relationship and maintaining the state as it is can be performed without an operator visually observing the combined portion. Therefore, even in a narrow space such as an engine room, it can be easily performed (by simply combining the steering shaft 23 and the yoke 24 with the hand).

  Based on the above-mentioned work, as shown in FIG. 11, after the steering shaft 23 and the base end portion 28 of the yoke 24 are combined in a regular positional relationship, the through hole formed in the one holding plate portion 29a. The male screw 56 formed in the flange portion 33 of the holding bolt 25 through which the screw 32 is inserted is screwed into the female screw 55 of the nut 26 and further tightened. As the screwing and tightening operations proceed, the male screw 56 reaches the caulking portions 57 and 57 formed at the open end of the female screw 55, and the nut 26 is tightened along with the tightening operation of the holding bolt 25. , Tends to swing with a large torque. The cam portion 53 provided on the outer peripheral surface of the distal end portion of the nut 26 presses the distal end portion of the steering shaft 23 toward the inner surface of the connecting portion 30 provided on the proximal end portion 28 of the yoke 24. As a result, the posture of the distal end portion of the steering shaft 23 is corrected following the inner surface of the connecting portion 30. Since the shape and the installation position of the inner surface of the connecting portion 30 are appropriately regulated in advance, the central axis of the steering shaft 23 and the central axis of the yoke 24 can be matched with each other based on this correction.

  In the example shown in the figure, the thickness of the gap between the holding surfaces 31 and 31 and the outer flat surfaces 27 and 27 is set in a state before the holding bolt 25 and the nut 26 are tightened. The widths of these surfaces 31 and 27 (the vertical direction in FIGS. 4 to 5) are substantially constant (the two restraining surfaces 31 and 31 and the outer flat surfaces 27 and 27 are parallel to each other). On the other hand, in a state before the tightening, the spacing between the both restraining surfaces 31, 31 is widened toward the opening of the base end portion 28 (upward in FIGS. 4 to 5). The holding plate portions 29a and 29 may be slightly inclined. If such a configuration is adopted, the contact pressure between the restraining surfaces 31 and 31 and the outer flat surfaces 27 and 27 is improved and the contact is made with the tightening of the restraining bolt 25 and the nut 26. By making the pressure uniform, the coupling strength between the steering shaft 23 and the yoke 24 can be improved.

  FIG. 12 shows Embodiment 2 of the present invention corresponding to claims 1 to 4. In the first embodiment described above, the present invention is applied to the joint portion between the universal joint yoke and the steering shaft. In the present embodiment, a straight connection between a pair of shafts 58a and 58b is used. The present invention is applied to the part. For this reason, in the case of the present embodiment, the tip of the yoke 24a (the right end in FIG. 12) is welded and fixed to the end of one of the shafts 58a (the right side in FIG. 12) formed into a circular tube. The base end portion 28a of 24a and the other shaft 58b (left side in FIG. 12) are coupled by the structure of the present invention. The structure of the connecting portion between the base end portion 28a and the other shaft 58b is the same as that in the first embodiment.

FIG. 13 shows a third embodiment of the present invention corresponding to the fifth aspect. In the case of the present embodiment, the first and second recesses 50a and 51a are respectively formed at two positions opposite to each other in the diameter direction of the tip portion of the shaft 59, and the first and second recesses 50a, 51a is made continuous by the respective continuous recesses 52a, 52a formed at four positions in the circumferential direction. The width dimensions W _50a and W _51a of the first and second recesses 50a and 51a in the axial direction of the shaft 59 are the same as each other, or the width dimension W _50a of the first recess 50a is It is slightly larger (W _50a ≧ W _51a) than the width W _51a of the second recess 51a.

In the case of the present embodiment, with such a configuration, the degree of freedom in the insertion direction of the distal end portion of the shaft 59 with respect to the proximal end portion of the yoke is improved (the opposite side may be 180 degrees). For this reason, it is possible to further facilitate the connecting operation between the shaft 59 and the yoke performed in a narrow engine room or the like. Further, since being slightly larger than the width W _51a of the first above the width W _50a of the recess 50a of the second recess 51a, fully pushing the shaft 59 until the back of the base end portion of the yoke In this state, the tip of the nut can easily enter the first recess 50a. In contrast, contrary to the case shown, when reduced slightly wider than the width W _51a of the width W _50a of the first recess 50a second recess 51a, said yoke to the shaft 59 The positioning accuracy in the axial direction of the shaft 59 and the yoke can be improved in a state after the assembly is completed while ensuring workability (ease of insertion) at the time of insertion into the base end portion. In this way, when the width dimensions are different from those shown in the figure, the width direction (the axial direction of the shaft 59) of the continuous recess 52a that makes the first and second recesses 50a and 51a continuous with each other. It is preferable to incline both inner side surfaces with respect to a virtual plane perpendicular to the axial direction. In addition, the structure in which the width dimensions of both the first and second recesses are changed and the inner surfaces in the width direction of the continuous recesses are inclined can be applied to the structures of the first and second embodiments.

  14 to 15 show a fourth embodiment of the present invention corresponding to claims 1 to 4. In the case of the present embodiment, the shaft 60 coupled to the yoke has a rectangular cross-sectional shape to facilitate processing of the shaft 60. The structure of the connecting portion between the tip end portion of the shaft 60 and the base end portion of the yoke is the same as that in the first embodiment.

  The present invention can be applied not only to the coupling portion in the steering device but also to the coupling portion between the shaft and the yoke incorporated in various mechanical devices. Also, when applied to a steering device, it can also be applied to a buffer mechanism such as a rubber coupling, a displacement absorbing mechanism in the event of a collision, or an intermediate shaft assembly combining these. Even when the present invention is applied to a steering device, various types of steering devices such as column type and other electric power steering devices, hydraulic power steering devices, non-power steering devices, etc. It becomes a target.

  Further, there are no particular limitations on the dimensions and materials of each part. For example, in the case of Example 1 shown in FIGS. 1 to 11, the male screw 56 formed on the holding bolt 25 and the female screw 55 formed on the nut 26 are M10 × 1.25, and the outer diameter of the steering shaft 23 is 16. 6 mm, the distance between the restraining surfaces 31, 31 of the pair of restraining plate portions 29a, 29b constituting the base end portion 28 of the yoke 24 is 13.5 mm, outside the four end portions of the cross shaft constituting the universal joint Although the diameter is 10 mm and the outer diameter of the radial needle bearing (which constitutes each of these end portions) is 16 mm, it is also possible to carry out by greatly changing these dimensions. In the above embodiment, the yoke 24 is a hot rolled steel plate, a rolled steel plate for automobile structure, etc., which is formed by pressing a steel plate having a thickness of about 6 to 6.5. The dimensions, materials, and processing methods are not limited to these. For example, a metal material such as an iron-based alloy, an aluminum-based alloy, or a magnesium-based alloy can be subjected to plastic working such as hot forging, cold forging, warm forging, or such a metal material can be cast. .

  Further, both the first and second recesses formed at the tip of the shaft are provided with continuous recesses 52 and 52a as shown in Examples 1 and 3 (see FIGS. 4, 9 to 11 and 13). Although it is preferable, like Example 4, a continuous recessed part may not be provided (refer FIGS. 14-15). In addition, the work of restricting the yoke and the shaft to the proper positional relationship after assembly is somewhat troublesome, but the first recess and the second recess are not continuous (displaced with respect to the axial direction of the shaft). You can also. In this case, the first recess is formed at a position corresponding to the normal position after the assembly is completed. Furthermore, the bottom surface of the second recess is not necessarily parallel to the outer plane of the shaft, and may be slightly inclined.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a rotation transmission device for a steering device that incorporates a coupling portion between a shaft and a yoke for explaining a first embodiment of the present invention. The A section enlarged view of FIG. 1 shown in the state which cut | disconnected a part. The figure seen from the upper part of FIG. BB sectional drawing of FIG. The figure similar to FIG. 4 shown in the state before assembling a shaft and a volt | bolt. The partial cut side view which took out the nut and was seen from the same direction as FIGS. The figure seen from the right side of FIG. The same view from the left. The side view which took out the steering shaft and was seen from the same direction as FIG. The same figure as FIG. 4 which shows the state in the middle of pushing a steering shaft into the base end part of a yoke. The figure similar to FIG. 4 which shows the state which pushed the steering shaft into the base end part of the yoke. The partial cutting side view which shows Example 2 of this invention. The side view of the front-end | tip part of a shaft which shows the same Example 3. FIG. The side view of the front-end | tip part of a shaft which shows the same Example 4. FIG. CC sectional drawing of FIG. A side view showing an example of conventional structure. DD sectional drawing of FIG. EE sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Universal joint 2, 3 Yoke 4 Cross shaft 5 Bearing cup 6, 7 Shaft 8 Base end part 9a, 9b Holding plate part 10 Holding surface 11 Nut 12 Screw hole 13 Through-hole 14 Outer plane 15 Recessed part 16 Outer shaft 17 Inner shaft 18 Spline engaging portion 19 Intermediate shaft 20 Universal joint 21 Universal joint 22 Steering shaft 23 Steering shaft 24, 24a Yoke 25 Retaining bolt 26 Nut 27 Outer plane 28, 28a Base end portion 29a, 29b Retaining plate portion 30 Connecting portion 31 Retaining surface 32 Through hole 33 collar part 34 head 35 male thread part 36 collar part 37 mounting hole 38 cover 39 main part 40 inward collar part 41a, 41b, 41c outward collar part 42 leg piece 43 concave hole 44 compression coil spring 45 through hole 46 linear edge 47 Flat surface 48 Engagement step surface 49 Inclined surface 5 0, 50a First concave portion 51, 51a Second concave portion 52, 52a Continuous concave portion 53 Cam surface 54 Flat surface 55 Female screw 56 Male screw 57 Caulking portion 58a, 58b Shaft 59 Shaft 60 Shaft

Claims (5)

  A shaft that rotates during use, a yoke that constitutes a joint, and a holding bolt and a nut that connect the shaft and the yoke are provided. Of these, the shaft forms a pair of outer flat surfaces on the outer peripheral surface of the tip. The yoke has a base end portion that is open on the side, and the base end portions are spaced apart from each other, and each pair of inner side surfaces serves as a restraining surface that faces each of the outer side flat surfaces. Formed on the holding plate portion, the connecting portion that connects these holding plate portions to each other at the portion opposite to the opening of the base end portion, and the one holding plate portion of the both holding plate portions, A through-hole of the holding bolt that can be freely inserted and does not allow the head of the holding bolt to pass through, and the nut is assembled to the other holding plate of the holding plates. Insert the tip part between the two holding plate parts In this state, by connecting the male threaded portion of the restraining bolt inserted through the through hole to the nut, the restraining surface of the restraining plate portions is pressed against the both outer planes, and the shaft-yoke coupling portion In this case, the nut has a portion closer to the tip than the step surface formed on the outer circumferential surface of the intermediate portion in the axial direction so as to face the outer surface of the other restraining plate portion, and a part of the other restraining plate portion. Is fitted inside the circular mounting hole formed concentrically with the through-hole so as to be capable of displacement in the direction of the central axis of the mounting hole and swinging around the central axis, and the tip portion is connected to the other side. Elasticity in the direction of projecting from the restraining surface of the restraining plate portion is provided, and on the outer peripheral surface of the tip portion of the shaft, the surface opposite to the connecting portion and the restraining surface of the other restraining plate portion The position of this shaft in the axial direction on a part of the facing surface The first and second recesses having a width dimension in the axial direction larger than a width dimension in the same direction of the tip edge portion of the nut are formed in a portion to be aligned with the through hole and the mounting hole in the assembled state. In addition, an inclined surface that is inclined in a direction approaching the one holding plate portion as the closer to the connecting portion is formed at a portion on the opposite side of the connecting portion of the tip portion of the nut, and the tip portion of the nut Limiting the amount of displacement in the direction of retreating from the tip of the shaft, the surface facing the restraining surface of the other restraining plate in the tip edge of the nut and the outer peripheral surface of the tip of the shaft The tip end of the shaft is moved closer to the connecting portion side than the tip end edge of the nut only in a state where the second recess formed in is aligned, and the tip end edge of the nut and the first recess are The system is characterized by engaging The joint between the shaft and the yoke.   A portion of the front end portion of the nut facing the connecting portion is connected to the bottom surface of the first recess formed on the surface on the opposite side of the outer peripheral surface of the front end portion of the shaft as the nut rotates. Based on the engagement, a cam portion that presses the tip of the shaft toward the connecting portion is formed, and in a part of the screwed portion of the female screw formed on the nut and the male screw formed on the holding bolt, The joint part of the shaft and yoke described in Claim 1 which has provided the resistance part for increasing the sliding resistance of the screwing part of these internal threads and external threads.   The step surface is one axial side surface of the outward flange-shaped flange portion provided on the outer circumferential surface of the nut in the axial direction of the nut, and the inner surface of the cover fixed to the outer surface of the other holding plate portion and the flange portion The elastic force of the direction which makes the front-end | tip part of the said nut protrude from the restraining surface of said other restraining board part with the spring provided between the other axial side surfaces is given in any one of Claims 1-2. The joint part of the shaft and yoke described in item 1.   The base end of the nut is inserted inside the through-hole formed in the cover so that the nut can be displaced in the axial direction. On the inner surface of the cover, the peripheral portion of the through-hole and the axial intermediate portion of the nut The shaft and the yoke according to claim 3, wherein the amount of displacement of the tip of the nut in the direction of retreating from the tip of the shaft is limited based on the engagement with the engagement step surface formed on the shaft. Coupling part.   The coupling of the shaft and the yoke according to any one of claims 1 to 4, wherein the first and second recesses are respectively formed at two positions on the diametrically opposite side of the tip portion of the shaft. Department.

Images