JP2008069817A - Connecting structure for universal coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting structure for a universal coupling inhibiting drop of retention force of a connecting part of a shaft and a yoke and improving installability. <P>SOLUTION: In this connecting structure for the universal coupling, a fastened part 3A of the steering shaft and a fastening part 12A of the yoke are mutually engaged by serrations 3b, 14, and the fastened part 3A is fastened by the fastening part 12A with using a bolt 12. Moreover, the fastened part 3A has a part having the serration 3b thereon on an outer circumference surface passing through a position where the bolt 13 is inserted and a part having a bolt insertion groove 3D through which the bolt 13 can be inserted formed along a circumference direction thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a universal joint connection structure, and more particularly to a universal joint connection structure that can be suitably used in, for example, an automobile steering device.
About.

For example, an automobile steering device is configured to transmit the movement of a steering shaft that rotates in accordance with the operation of a steering wheel to an input shaft of a steering gear via a cross-shaped universal joint (universal joint).
This type of universal joint connection structure includes a cylindrical shaft and a yoke having a fastening portion for fastening and fixing the shaft. The shaft and yoke tightening portions are coupled (engaged) with each other so that the movement in the circumferential direction is restricted by serrations or splines, etc., and the shaft is bolted by the yoke tightening portion. It can be tightened (see, for example, Patent Documents 1 and 2).

  For example, in the technique described in Patent Document 1, as illustrated in FIG. 7, a serration 111 a is processed on the outer peripheral surface of the tightened portion 111 of the shaft 110. Furthermore, a groove 111b through which the bolt can be inserted is formed on the outer peripheral surface passing through the position where the bolt for tightening the tightened portion 111 is inserted in the tightened portion 111. Is done. Therefore, in the portion where the groove 111b is formed, the serration 111a is cut out over the entire circumference of the shaft (see, for example, FIG. 1 in the publication).

  Further, in the technique described in Patent Document 2, for example, as illustrated in FIG. 8, the shaft 120 is straight along a bolt insertion direction at a position where a bolt for tightening the tightened portion 112 is inserted. Thus, a cutout portion 112b is formed by cutting out a part thereof. A bolt is inserted into the notch 112b (see, for example, FIG. 4 in the same publication).

In any of the above patent documents, a bolt is inserted along the notched portion of the shaft from the axial direction of the tightening portion of the yoke, and the tightened portion of the shaft can be tightened by this bolt. It has become.
Japanese Utility Model Publication No. 02-34379 Japanese Utility Model Publication No. 58-44508

  However, for example, as in the technique described in Patent Document 1, if a portion that is notched over the entire circumference of the tightened portion is provided in the shaft, the tightened portion of the shaft and the yoke are correspondingly provided. Since the fitting length due to serrations or splines between the tightening portions is shortened, there is a problem that the holding force for holding the shaft is reduced. In addition, in order to suppress the decrease in holding power, for example, it is possible to tighten processing tolerances such as serrations, or to rank the shaft and yoke serrations according to quality, and select and combine them appropriately. However, in this case, it is disadvantageous in terms of cost, such as requiring a process for that purpose. In addition, it is conceivable that the spline is lengthened and the fitting length is lengthened, but there is a limitation on the layout.

  On the other hand, for example, as in the technique described in Patent Document 2, if a straight notch is provided along a bolt insertion direction in a part of the tightened portion, the entire periphery of the tightened portion is provided. Although it is possible to suppress a decrease in holding force as compared with a notched portion, the mounting position between the shaft and the yoke is limited by the notch forming position, so the position in the circumferential direction of the shaft ( Hereinafter, when the position of the shaft in the circumferential direction is also referred to as “phase”, there is a problem that the bolt cannot be assembled.

  That is, for example, as illustrated in FIG. 9, when a linear notch 112 b along the insertion direction of the bolt 13 is provided in a part of the tightened portion 112 of the shaft, the phase of the shaft is the desired position. If it is VL, it can be assembled as shown in FIG. However, when the number of teeth of the serration 112a is 36, for example, if the phase of the shaft deviates from the expected position VL even if the angle θ is only 10 ° (one tooth), it is illustrated in FIG. As described above, since interference occurs in the portion indicated by the symbol X, the bolt 13 cannot be assembled due to a phase shift. In other words, the position where the shaft and the yoke can be coupled to each other is limited to an extremely narrow range, and therefore, in the assembly work during the production, it is necessary to check the phase of the shaft accurately and to attach it to the yoke. Therefore, the efficiency of the assembling work is reduced accordingly. Therefore, it is also disadvantageous in terms of cost.

  Therefore, the present invention has been made paying attention to such a problem, and a universal joint capable of suppressing a decrease in holding force at the joint portion between the shaft and the yoke and improving the assemblability. It is intended to provide.

  In order to solve the above problems, a first invention of the present invention comprises a cylindrical shaft and a yoke having a tightening portion for tightening and fixing the shaft, and the shaft and the yoke are tightened. Each of the attachment portions has a serration portion or a spline portion that engages with each other so as to restrain movement in the circumferential direction, and the shaft is bolted by a fastening portion of the yoke. In the connecting structure, the shaft includes a portion in which the serration portion or the spline portion is formed on an outer peripheral surface passing through a position where the bolt is inserted, and a bolt insertion groove into which the bolt can be inserted in the circumferential direction. And a portion formed along the line.

  According to the universal joint connection structure of the present invention, the shaft is formed with a serration portion or a spline portion and a bolt insertion groove on the outer peripheral surface passing through the position where the bolt is inserted. A decrease in holding force is suppressed as compared with the case where a portion cut out over the circumference is provided. Furthermore, since the bolt insertion groove is formed so that the bolt can be inserted along the circumferential direction of the shaft, the phase of the shaft can be shifted within the range in which the bolt can be inserted. Therefore, the assemblability can be improved as compared with the case where a cutout is provided only in the insertion direction of the bolt in a part of the shaft.

  The second aspect of the present invention includes a cylindrical shaft and a yoke having a tightening portion for tightening and fixing the shaft, and the shaft and the tightening portion of the yoke are mutually connected. A joint structure of universal joints, each having a serration part or a spline part engaging with movement in the circumferential direction so as to be restrained, and wherein the shaft is tightened with a bolt by a tightening part of a yoke, The shaft has a bolt insertion groove through which the bolt can be inserted along the circumferential direction in a part of an outer peripheral surface passing through a position where the bolt is inserted, and a portion other than the bolt insertion groove is It is the serration part or the spline part.

  According to the universal joint coupling structure of the present invention, the shaft has a bolt insertion groove formed on the outer peripheral surface passing through the position where the bolt is inserted, and the bolt insertion groove is a part of the circumferential direction. Therefore, a decrease in holding force is suppressed as compared with the case where a portion cut out over the entire circumference is provided. Further, since the bolt insertion groove is formed so that the bolt can be inserted along the circumferential direction, the phase of the shaft can be shifted within the range in which the bolt can be inserted. Therefore, the assemblability can be improved as compared with the case where a part of the tightened portion is notched only along the bolt insertion direction.

  The third aspect of the present invention includes a cylindrical shaft and a yoke having a tightening portion for tightening and fixing the shaft, and the shaft and the tightening portion of the yoke are mutually connected. A joint structure of universal joints, each having a serration part or a spline part engaging with movement in the circumferential direction so as to be restrained, and wherein the shaft is tightened with a bolt by a tightening part of a yoke, The shaft has a bolt insertion groove through which a bolt can be inserted only in a part of the outer peripheral surface that passes through the position where the bolt is inserted, and the bolt insertion groove is further tightened between the shaft and the yoke. It is characterized in that it is formed with an allowable range that allows movement of the engagement position in the circumferential direction of the serration portion or spline portion between the attachment portions.

  According to the universal joint coupling structure of the present invention, the shaft has a bolt insertion groove formed on the outer peripheral surface passing through the position where the bolt is inserted, and the bolt insertion groove is a part of the circumferential direction. Therefore, a decrease in holding force is suppressed as compared with the case where a portion cut out over the entire circumference is provided. Further, the bolt insertion groove is formed with an allowable range allowing the movement of the engagement position in the circumferential direction of the serration portion or the spline portion between the tightening portions of the shaft and the yoke. Bolts can be inserted even if the phase of the shaft is shifted. Therefore, the assemblability can be improved as compared with the case where a part of the tightened portion is notched only along the bolt insertion direction.

  The fourth aspect of the present invention includes a cylindrical shaft and a yoke having a tightening portion for tightening and fixing the shaft, and the shaft and the tightening portion of the yoke are mutually connected. A joint structure of universal joints, each having a serration part or a spline part engaging with movement in the circumferential direction so as to be restrained, and wherein the shaft is tightened with a bolt by a tightening part of a yoke, The shaft has a bolt insertion groove through which a bolt can be inserted only in a part of the outer peripheral surface that passes through the position where the bolt is inserted, and the bolt insertion groove is further tightened between the shaft and the yoke. A convex arc portion having an allowable range that allows movement of the engagement position in the circumferential direction of the serration portion or the spline portion between the appendages, and both sides of the convex arc portion Provided respectively is characterized in that it is formed with a, a connecting portion connecting the arc portion of the convex the serration portion or spline portion.

  According to the universal joint coupling structure of the present invention, the shaft has a bolt insertion groove formed on the outer peripheral surface passing through the position where the bolt is inserted, and the bolt insertion groove is a part of the circumferential direction. Therefore, a decrease in holding force is suppressed as compared with the case where a portion cut out over the entire circumference is provided. Further, the bolt insertion groove includes a convex arc portion having an allowable range allowing movement of the engagement position in the circumferential direction of the serration portion or spline portion between the tightening portions of the shaft and the yoke, and the convex arc portion. And a connecting portion that connects the serration portion or the spline portion, the bolt can be inserted even if the phase of the shaft is shifted within the allowable range of the convex arc portion. Therefore, the assemblability can be improved as compared with the case where a part of the tightened portion is notched only along the bolt insertion direction. Furthermore, since the shape having such an allowable range is formed by a convex arc portion, for example, it is possible to reduce a portion to be cut out as compared with a case in which a linear cutout is provided along the bolt insertion direction. it can. Therefore, the strength of the shaft can be kept relatively.

  As described above, according to the present invention, it is possible to provide a coupling structure for a universal joint that can suppress a decrease in holding force at the joint between the shaft and the yoke and can improve the assembling property.

Hereinafter, an embodiment in which a coupling structure of a universal joint according to the present invention is applied to a steering mechanism of a vehicle will be described with reference to the drawings.
First, the overall configuration of the vehicle steering shaft will be described.
FIG. 1 is a side view of a steering mechanism portion of an automobile to which a universal joint according to the present invention is applied.
As shown in the figure, the steering mechanism portion includes an upper steering shaft portion 1 attached to a member on the vehicle body side. The upper steering shaft portion 1 rotates on the steering column 4 and the steering column 4. And a steering shaft 3 that is freely held.

  A steering wheel 5 is attached to the upper end of the steering shaft 3. Further, the lower end of the steering shaft 3 is connected to a universal joint 7, and is connected to a lower steering shaft portion 9 that can be expanded and contracted via the universal joint 7. The lower steering shaft portion 9 is capable of turning the steered wheels according to the steering of the steering wheel 5 by way of the steering shaft coupling 8 and further via a steering force transmission mechanism (not shown). Yes. Here, the universal joint 7 and the steering shaft joint 8 correspond to the universal joint according to the coupling structure of the universal joint of the present invention.

Hereinafter, the universal joint 7 and the steering shaft 3 coupled thereto will be described in detail.
The universal joint 7 has a structure in which a pair of yokes 11 and 12 are connected as shown in FIG.
Each of the yoke 11 and the yoke 12 has a pair of arm portions 2 and 23 formed in a substantially U shape, and a bearing hole 6 is provided in the vicinity of the distal end portions of the pair of arm portions 2 and 23, respectively. ing. The yoke 11 and the yoke 12 are rotatably connected to each other via a bearing (needle bearing) 15 by a spider (cross joint) 17 composed of two orthogonal axes at the distal ends of the arm portions 2 and 23. ing. The bearing 15 is attached to the arm portions 2 and 23 by press-fitting into each bearing hole 6 and caulking 16. Furthermore, a resin-made thrust piece 18 is attached to each tip portion of two orthogonal shafts of the spider 17 so that the spider 17 can be positioned in the axial direction.

  A shaft 10 connected to the steering gear side is formed integrally with the pair of arm portions 2 on the yoke 11 side. On the other hand, in the yoke 12, the base end portion of the pair of arm portions 23 is a substantially cylindrical body portion 12B, and the body portion 12B is formed integrally with the arm portion 23. Furthermore, the side opposite to the arm portion 23 in the body portion 12B in the axial direction is formed as a tightening portion 12A. The trunk portion 12B and the tightening portion 12A have a substantially cylindrical shape whose outer diameter and width are substantially the same dimension, and the substantially cylindrical inner circumference extends from the trunk portion 12B to the end of the tightening portion 12A. Open to communicate. The lower end of the steering shaft 3 has a solid cylindrical shape with an outer diameter that can be inserted into the tightening portion 12A of the yoke 12, and the lower end of the steering shaft 3 is tightened to the yoke 12 with the tightening portion 12A. Inserted from the side and fixed. That is, the lower end of the steering shaft 3 is a tightened portion 3A that is fastened to the tightening portion 12A of the yoke 12, and the shaft according to the universal joint coupling structure of the present invention is the steering shaft in this embodiment. The shaft 3 corresponds.

Hereinafter, the tightened portion 3A of the steering shaft 3 and the tightened portion 12A of the yoke 12 will be described in more detail with reference to FIGS.
FIG. 3 is a view for explaining the tightened portion 3A of the steering shaft 3. FIG. 3 (a) is a side view thereof, and FIG. 3 (b) is an A view in FIG. It is -A sectional drawing. FIG. 4 is a diagram for explaining a joint portion between the steering shaft 3 and the yoke 12. FIG. 4 is a cross-sectional view in a direction perpendicular to the axis at a position where the bolt 13 is inserted in the joint portion. (A) shows a state in which the bolt is inserted at the desired position, and (b) in the circumferential direction of the shaft. The position of is shifted in the rotational direction from the intended position.

  As shown in FIG. 2, serrations 3 b are formed in the tightened portion 3 </ b> A of the steering shaft 3 along the axial direction thereof. Further, the yoke 12 includes the body portion 12B, and the serration 3b formed on the tightened portion 3A of the steering shaft 3 can be inserted into the inner peripheral surface of the tightening portion 12A and moved in the circumferential direction. Serrations 14 are formed along the axial direction so as to be able to engage with each other.

  Here, the serrations 3b and 14 formed respectively on the outer peripheral surface of the tightened portion 3A of the steering shaft 3 and the inner peripheral surface of the tightening portion 12A of the yoke 12 serve as circumferential movement restraining means. The shaft tightening portion and the yoke tightening portion are engaged with each other so as to restrain movement in the circumferential direction. The serration 3b of the tightened portion 3A has 36 teeth, and the serration 14 of the tightening portion 12A has valleys corresponding to the teeth of the serration 3b formed at 36 locations along the circumferential direction. . Therefore, the mutual engagement position (phase) in the circumferential direction can be moved every 10 ° (number of teeth 1). The serrations 14 and 3b correspond to the serration units, respectively.

  Further, the yoke 12 has a bolt insertion portion 12 </ b> C that protrudes in one of the radial directions at the tightening portion 12 </ b> A. As shown in FIG. 4, the bolt insertion part 12C is formed with a slit 12g for clamping so as to penetrate the bolt insertion part 12C to the inner peripheral surface so as to divide the bolt insertion part 12C in the radial direction. A bolt hole 12d through which a hugging bolt 13 can be inserted and a screw hole 12e having a female screw that can be screwed into the male screw portion of the bolt 13 are provided to face each other from a direction perpendicular to the bolt 13. Note that M8 × 1.25 is used for the bolt 13 screwed into the screw hole 12e. Then, the tightened portion 3A of the steering shaft 3 is inserted into the tightening portion 12A of the yoke 12, and is further fastened and fixed through the washer 19 by the bolt 13 inserted through the bolt insertion portion 12C of the tightening portion 12A. ing.

  Further, as shown in FIG. 3, the tightened portion 3A of the steering shaft 3 has a bolt insertion groove 3D formed on the outer peripheral surface at a position where the bolt 13 is inserted. Specifically, as shown in FIG. 3A, the bolt insertion groove 3D is formed substantially at the center in the axial direction of the tightened portion 3A, which is a position where the bolt 13 is inserted. That is, the position where the bolt 13 is inserted is in the middle of the tightened portion 3 </ b> A of the steering shaft 3. The width W is slightly larger than the outer diameter of the bolt so that the bolt 13 can be inserted. More specifically, when the bolt of M8 × 1.25 is used, it is preferable that the width W of the bolt insertion groove 3D is in the range of 8.5 to 13 mm.

  Further, as shown in FIG. 3B, the bolt insertion groove 3 </ b> D is a substantially U-shaped groove through which the bolt 13 can be inserted when the cross section in the axial direction at the position where the bolt 13 is inserted is seen. Is formed along the circumferential direction and only in a part of the circumferential direction. In this example, the bolt insertion groove 3D is formed in the lower half (approximately 180 ° range) of the outer peripheral surface of the tightened portion 3A at the position where the bolt 13 is inserted. The upper half is the serration 3b described above. That is, the tightened portion 3A of the steering shaft 3 has a portion where the serration 3b is formed on the outer peripheral surface passing through the position where the bolt 13 is inserted, and a bolt insertion groove 3D through which the bolt 13 can be inserted. And a portion formed along the direction.

  More specifically, when the bolt insertion groove 3D is set with respect to the axis line VL for left and right distribution as a reference position as the intended position of the steering shaft 3, as shown in FIG. A range of about 60 ° on each of the left and right sides is a region α formed by a convex arc portion 3c having a radius R concentric with the steering shaft 3. And the radius R of this convex circular arc part 3c is set to the dimension which does not interfere with the axial part of the volt | bolt 13 when inserting the volt | bolt 13 in 3 A of to-be-tightened parts. Here, as shown in FIG. 4, the distance DB from the center of the steering shaft 3 to the bolt axis (bolt insertion position) is in the range of 10 to 20 mm when the M8 × 1.25 bolt is used. Setting is preferable. If this distance DB is set within this range, it is preferable to make the fastening force with the bolts 13 effective while keeping the shaft diameter (thickness) of the steering shaft 3 as much as possible. The radius R of the convex arc portion 3c is a dimension in which the position on the axis VL of the convex arc portion 3c is the apex, and the apex position is in sliding contact with the axial portion of the bolt 13 or with a slight gap. Is set to

Further, the left and right sides of the region α forming the convex arc portion 3c are smoothly connected to the portion where the serration 3b closest to the bolt 13 is formed via the concave arc portion 3e. The concave arc portion 3e corresponds to the connecting portion.
The universal joint connection structure has the above-described configuration, so that the tightened portion 3A of the steering shaft 3 is connected to the tightened portion 12A of the yoke 12 as shown in FIGS. 4 (a) and 4 (b). It is possible to attach to.

That is, according to this universal joint connection structure, as shown in FIG. 5A, if the phase of the steering shaft 3 is the desired position VL, the tightening portion of the yoke 12 is the same as the conventional example described above. When the bolt 13 is inserted into 12A and the bolt 13 is tightened, the tightened portion 3A of the steering shaft 3 can be tightened by the tightening portion 12A of the yoke.
Furthermore, according to the connecting structure of the universal joint, as shown in FIG. 5B, the steering shaft 3 has an area where the bolt insertion groove 3D is the convex arcuate portion 3c with respect to the intended position VL. Since α is included, it has a rotatable range on each of the left and right of the intended position VL. That is, the bolt insertion groove 3D has an allowable range that allows movement of the coupling position in the circumferential direction of the tightened portion 3A and the tightening portion 12A, and therefore the phase of the steering shaft 3 is shifted within the allowable range. Can also be attached to the fastening portion 12A of the yoke.

  Here, in the example of the present embodiment, the allowable range is a range of 40 ° on each of the left and right sides of the intended position VL (four teeth each). That is, as shown in FIG. 4B, when the phase of the steering shaft 3 is shifted by the angle θ with respect to the tightening portion 12A of the yoke 12, the teeth of the serration 3b closest to the bolt 13 in the circumferential direction are the bolt 13 In this case, as long as the teeth of the serration 3b closest to the bolt 13 in this circumferential direction are in contact with the shaft of the bolt 13, the right and left of the intended position VL This is because each can rotate. Here, the region α itself is formed within a range of about 60 ° on the left and right sides of the intended position VL, but the rotation until the teeth of the serration 3b located at the end abut the shaft portion of the bolt 13 is made. In this example, the angle (the above-described allowable range) is 40 ° to the left and right of the intended position VL.

Next, the operation and effect of the universal joint connection structure will be described.
As described above, according to the connecting structure of the universal joint, the steering shaft 3 has the serration 3b and the bolt insertion groove 3D on the outer peripheral surface passing through the position where the bolt 13 is inserted in the tightened portion 3A. Therefore, a decrease in holding force is suppressed as compared with, for example, the above-described example in which a portion cut out over the entire circumference is provided.

Further, since this bolt insertion groove 3D is formed so that the bolt 13 can be inserted along the circumferential direction of the tightened portion 3A, even if the phase of the steering shaft 3 is shifted within the formed range. The bolt 13 can be inserted.
That is, in the present embodiment, the allowable range in which the movement of the coupling position in the circumferential direction between the tightened portion 3A and the tightened portion 12A is set to 40 ° on each of the left and right of the intended position VL (4 in terms of the number of teeth, respectively). Therefore, the bolt 13 can be inserted even if the phase of the steering shaft 3 is shifted within the allowable range. Conversely, since an allowable range is formed so that the bolt 13 can be inserted along the circumferential direction, the phase of the steering shaft 3 can be shifted within the allowable range. Therefore, for example, the assembling property can be improved as compared with the above-described example in which the notched portion is provided with a notch only along the insertion direction of the bolt.

  Here, as understood from the above description, for example, “providing a notch only along the insertion direction” as illustrated above, and “notch along the circumferential direction (bolt insertion groove) It is a different concept from “providing 3D) only in a part thereof”. Therefore, in the assembling work at the time of manufacture, if the phase of the steering shaft 3 is within the above-described allowable range, it can be attached to the yoke 12. Therefore, the trouble of checking the phase at the time of mounting is reduced, and the efficiency of the assembling work is reduced. That will improve. Therefore, it is advantageous in terms of cost.

Furthermore, according to the connecting structure of this universal joint, the bolt insertion groove 3D is formed with the convex arc portion 3c having the above-mentioned allowable range, and both sides of the convex arc portion 3c are provided on the serration 3b. Since it is configured by smoothly continuing to the position on the bolt 13 side via the concave arc portion 3e, stress concentration in the bolt insertion groove 3D portion is alleviated.
In particular, according to the coupling structure of this universal joint, in order to have an allowable range equivalent to the allowable range in the present application described above, for example, "with a linear notch along the bolt insertion direction", Compared with the case where the linear cutout is provided large (deeply), the cutout portion can be significantly reduced. Therefore, the strength of the shaft can be kept relatively low by suppressing the decrease in strength at the bolt insertion groove 3D.

In addition, the connection structure of the universal joint which concerns on this invention is not limited to the said embodiment, A various deformation | transformation is possible unless it deviates from the meaning of this invention.
For example, in the above embodiment, the universal joint connection structure according to the present invention has been described as an example applied to a steering mechanism portion of a vehicle. However, the present invention is not limited to this, and the shaft and the tightened portion of the shaft are tightened. A yoke having a tightening portion for fixing the shaft, and the tightened portion of the shaft and the tightening portion of the yoke are engaged with each other by circumferential movement restraining means such as serrations, and the shaft The universal joint connection structure according to the present invention can be suitably applied as long as the to-be-tightened part is a universal joint connection structure that is tightened with a bolt by a yoke fastening part.

  For example, the universal joint according to the present invention is not limited to the universal joint 7 and the steering shaft joint 8, but may be applied to an appropriate universal joint if it is applied to a universal joint disposed on the steering shaft. Can do. Further, for example, in the above embodiment, the steering shaft 3 has been described as an example corresponding to the shaft related to the universal joint connection structure of the present invention. However, the shaft applicable to the shaft related to the universal joint connection structure of the present invention is also applicable. Of course, the present invention is not limited to the steering shaft. For example, the drive shaft may be a shaft according to the universal joint coupling structure of the present invention, and the universal joint according to the present invention may be applied to the universal joint.

  Further, for example, in the above-described embodiment, the shaft tightening portion and the yoke tightening portion are described as examples in which serrations that can be engaged with each other are provided as circumferential movement restraining means, but the present invention is not limited thereto. Instead, the circumferential movement restraining means may be, for example, a spline instead of the serration. In other words, in a configuration that allows the movement in the axial direction to be allowed while restraining the movement in the circumferential direction between the tightened portion of the shaft and the tightening portion of the yoke, as the circumferential movement restraining means, It is preferable to employ serrations or splines. When a spline is employed as the circumferential movement restraining means, the spline portion corresponds to a spline formed to be engageable with each of the shaft tightened portion and the yoke tightened portion.

  In the above embodiment, the tightened portion 3A of the steering shaft 3 has a region α in which the bolt insertion groove 3D is formed by a convex arc portion 3c having a radius R concentric with the steering shaft 3. The region α has been described as an example in which the portion where the serration 3b is formed is smoothly continuous via the concave arc portion 3e, but the configuration of the bolt insertion groove 3D is not limited to this. Absent.

  For example, although the convex arc portion 3c has been described in the example in which the center of the radius R is formed concentrically with the steering shaft 3, the present invention is not limited to this, and may be formed with the above-described allowable range. For example, it may be eccentric. Further, the convex arc portion 3c is not limited to a single arc, and may be formed by a convex curve composed of a combination of a plurality of arcs. However, in order to provide the above-described allowable range and facilitate its manufacture, it is preferable that the center of the radius R of the convex arc portion 3 c is a single arc formed concentrically with the steering shaft 3.

For example, the modification of bolt insertion groove 3D is shown in FIG. 5 and FIG.
The example shown in FIGS. 5 and 6 differs from the above embodiment only in that the configuration of the bolt insertion groove 3D includes a linear portion 3f instead of the concave arc portion 3e as a connecting portion. ing.
That is, as shown in FIGS. 5 and 6, the straight line portion 3 f that connects the portion where the serration 3 b is formed and the convex arc portion 3 c having the radius R is located at the tangent line and the end of the convex arc portion 3 c. It is formed so as to connect to the serration 3b. With such a configuration, the bolt insertion groove 3D is formed while the rotation angle (the above-described allowable range) until the teeth of the serration 3b located at the end abut the shaft portion of the bolt 13 is the same as in the above embodiment. In doing so, the cutting part at the time of the processing can be reduced. Therefore, the strength can be further improved.

  In the above embodiment, the bolt insertion groove 3D is formed on the outer peripheral surface of the tightened portion 3A at the position where the bolt 13 is inserted, in the lower half (approximately 180 ° range). However, the present invention is not limited to this, and the range in which the bolt insertion groove 3D is formed is limited to a part of the circumferential direction of the section where the bolt 13 is inserted and the section in the axial direction is seen. It only has to be formed. For example, in the above example, the range is approximately 180 ° (90 ° to the left and right of the axis VL with respect to the axis VL), but this is, for example, 30 °, 60 °, 90 °, or 180 ° or more. It can be set as appropriate.

It is a side view of the steering mechanism part of the motor vehicle which applied the connection structure of the universal joint which concerns on this invention. It is the Y section enlarged view in FIG. It is a figure explaining the to-be-tightened part of a steering shaft. It is a figure explaining the coupling | bond part of a steering shaft and a yoke, The figure (a) and (b) has each shown the ZZ cross section in FIG. It is a figure explaining the modification of the connection structure of the universal joint which concerns on this invention, The figure is shown in the figure corresponding to FIG. It is a figure explaining the modification of the connection structure of the universal joint which concerns on this invention, The figure is shown in the figure corresponding to FIG. It is a figure explaining the connection structure of the conventional universal joint, The figure (a) is a top view of the to-be-tightened part of a shaft, The figure (b) is CC sectional drawing in the figure (a). It is. It is a figure explaining the connection structure of the conventional universal joint, The figure (a) is a top view of the to-be-tightened part of a shaft, The figure (b) is BB sectional drawing in the figure (a). It is. FIG. 8 is a view for explaining a joint portion between shafts having a planar notch in a yoke and a tightened portion in a conventional universal joint connection structure, and is a cross-sectional view of the joint portion in a direction perpendicular to the axis; FIG. 4A shows a state in which the bolt is inserted along the flat notch, and FIG. 4B shows a state in which the position of the shaft in the circumferential direction is shifted. It shows an image where interference with the bolt occurs.

Explanation of symbols

1 Upper steering shaft part 2 Arm part 3 Steering shaft (shaft)
3A Clamped part 3D Bolt insertion groove 3b Serration (serration part)
3c Convex arc part 3e Concave arc part (connecting part)
3f Straight part (connecting part)
4 Steering column 5 Steering wheel 6 Bearing hole 7 Universal joint (universal joint)
8 Steering shaft joint 9 Lower steering shaft portion 10 (steering gear side) shaft 11 (steering gear side) yoke 12 yoke 12A tightening portion 13 bolt 14 serration (serration portion)
15 Bearing 16 Caulking 17 Spider 18 Thrust piece 19 Washer 23 Arm

Claims (4)

A cylindrical shaft, and a yoke having a tightening portion for tightening and fixing the shaft, and the shaft and the tightening portion of the yoke engage with each other so as to restrain movement in the circumferential direction. Each has a serration part or a spline part, and the shaft is a universal joint coupling structure in which the shaft is fastened with a bolt by a fastening part of a yoke,
The shaft has a portion where the serration portion or spline portion is formed on an outer peripheral surface passing through a position where the bolt is inserted, and a bolt insertion groove through which the bolt can be inserted along the circumferential direction. And a universal joint connection structure. A cylindrical shaft, and a yoke having a tightening portion for tightening and fixing the shaft, and the shaft and the tightening portion of the yoke engage with each other so as to restrain movement in the circumferential direction. Each has a serration part or a spline part, and the shaft is a universal joint coupling structure in which the shaft is fastened with a bolt by a fastening part of a yoke,
The shaft has a bolt insertion groove through which the bolt can be inserted along the circumferential direction in a part of an outer peripheral surface passing through a position where the bolt is inserted, and a portion other than the bolt insertion groove is A connection structure for a universal joint, characterized by being the serration portion or the spline portion. A cylindrical shaft, and a yoke having a tightening portion for tightening and fixing the shaft, and the shaft and the tightening portion of the yoke engage with each other so as to restrain movement in the circumferential direction. Each has a serration part or a spline part, and the shaft is a universal joint coupling structure in which the shaft is fastened with a bolt by a fastening part of a yoke,
The shaft has a bolt insertion groove through which a bolt can be inserted only in a part of the outer peripheral surface that passes through the position where the bolt is inserted, and the bolt insertion groove is further tightened between the shaft and the yoke. A connecting structure for a universal joint, characterized in that it has an allowable range that allows movement of the engaging position in the circumferential direction of the serration part or spline part between the attached parts. A cylindrical shaft, and a yoke having a tightening portion for tightening and fixing the shaft, and the shaft and the tightening portion of the yoke engage with each other so as to restrain movement in the circumferential direction. Each has a serration part or a spline part, and the shaft is a universal joint coupling structure in which the shaft is fastened with a bolt by a fastening part of a yoke,
The shaft has a bolt insertion groove through which a bolt can be inserted only in a part of the outer peripheral surface that passes through the position where the bolt is inserted, and the bolt insertion groove is further tightened between the shaft and the yoke. A convex arc portion having an allowable range that allows movement of the engagement position in the circumferential direction of the serration portion or the spline portion between the attachment portions, and the convex arc portion provided on both sides of the convex arc portion. And a connecting part that connects the serration part or the spline part.

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