JP2009144835A - Shaft joining structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joining structure of a steering shaft for reducing looseness with a simple constitution. <P>SOLUTION: This shaft joining structure has a lower shaft 32, and an upper shaft 30 having a hollow part capable of inserting the lower shaft 32. The lower shaft 32 and the upper shaft 30 are mutually fitted so as to be nonrotatable in the peripheral direction and slidable in the axial direction. The lower shaft 32 includes: an annular thin part 32c forming an end part of a part inserted into the upper shaft 30 thinner than a central part over the whole periphery; and an elastic member 44 deflected so as to press an inner peripheral surface of the annular thin part 32c in the radial direction. The annular thin part 32c is constituted so as to be elastically deformable when pressed outward in the radial direction by the deflected elastic member 44. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technology of a shaft coupling structure in an automobile steering device.

  Conventionally, in order to enable a driver to set an arbitrary operation position, a steering device that employs a telescopic mechanism that moves a steering wheel in the front-rear direction has been devised. Such a telescopic mechanism adopts a structure in which a shaft with serrations formed on the outer peripheral portion is inserted into a shaft with serrations formed on the inner peripheral portion, and coupled to each other so as to be non-rotatable and slidable in the axial direction. It is realized with.

  In such a coupling structure between the shafts, it is assumed that a backlash in the rotational direction occurs depending on variations in parts. Therefore, as one method for suppressing the play in the rotational direction, a resin is coated on the serration surface of the shaft. However, in order to coat the resin, an apparatus for dissolving and solidifying the resin is required, and a process of processing the resin coat layer into a serrated shape after coating the resin is necessary, resulting in an increase in cost.

  Therefore, instead of suppressing the occurrence of backlash in the rotational direction by forming the resin coat layer as described above, in Patent Document 1 and Patent Document 2, the outer shaft is assembled to the inner shaft, and then the adjustment screw is tightened. Thus, a coupling structure is disclosed in which the diameter-expanding member expands and the backlash is suppressed by pressing the inner shaft radially outward with respect to the outer shaft.

  In Patent Document 3, rattling is prevented by preloading all needle rollers by expanding the hollow end portion of the male shaft in which the slit is formed by the urging force of the spring pin radially outward. A telescopic shaft for steering is disclosed.

Japanese Patent Laid-Open No. 2001-347954 JP 2003-276615 A JP 2003-247560 A

  However, in the joint structure described in Patent Documents 1 and 2 described above, the shape of the diameter-expanding member is complicated, and the through holes must be formed in the inner shaft and the outer shaft. Therefore, it is necessary to tighten the adjusting screw, resulting in an increase in manufacturing cost and assembly cost. Further, in the telescopic shaft described in Patent Document 3, it is necessary to form a slit in the male shaft, which increases the manufacturing cost.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a shaft coupling structure with less play by a simple configuration.

  In order to solve the above problems, a shaft coupling structure according to an aspect of the present invention includes a first shaft and a second shaft having a hollow portion into which the first shaft can be inserted. A shaft coupling structure in which the first shaft and the second shaft are fitted to each other so as not to rotate in the circumferential direction and to be slidable in the axial direction. The end portion of the portion inserted into the shaft of No. 2 was bent so as to press the inner peripheral surface of the annular thin portion radially in the annular thin portion formed thinner than the central portion over the entire circumference. And an elastic member. The annular thin portion is configured to be elastically deformable when pressed toward the outside in the radial direction by the elastic member being bent.

  According to this aspect, the annular thin wall portion is pressed from the inside toward the outside in the radial direction by the elastic member in a state where the first shaft is inserted into the second shaft, and at least the end portion of the first shaft is outward. By elastically deforming toward the first shaft, the first shaft is more closely attached to the second shaft. As a result, the occurrence of play is suppressed with a simple configuration. In addition, since the annular thin portion is provided at the end of the first shaft, processing of the first shaft is facilitated.

  The first shaft is formed with a plurality of grooves extending linearly in the axial direction of the outer peripheral surface thereof, and the second shaft extends linearly in the axial direction of the inner peripheral surface of the first shaft. A plurality of convex portions that fit into the grooves may be formed in the circumferential direction.

  The elastic member may be an annular member, and may have a cutout part of which is cut out in the axial direction. Thereby, an elastic member can be easily bent by making the both ends which pinch | interpose a notch part close, and workability | operativity at the time of an assembly can be improved.

  The elastic member may have a circumferential length of the outer periphery longer than ½ of the entire circumferential length of the inner periphery of the annular thin portion. Thereby, it is reduced that an elastic member shifts or deviates from a predetermined position inside the annular thin portion.

  The elastic member may be a cylindrical spring having a U-shaped cross section when viewed from the axial direction of the first shaft. Thereby, an elastic member can be realized with a simple configuration, and the manufacturing cost can be reduced.

  The elastic member may have a protrusion formed on the outer peripheral surface thereof. Thereby, even if it does not finish an elastic member or an annular thin part with high processing accuracy, the variation in the place where an annular thin part is pressed by an elastic member is reduced, and the desired inner side of the annular thin part corresponding to the position of a projection is reduced. The portion is stably pressed, and the annular thin portion is easily elastically deformed as designed.

  The protrusions may be formed on both ends of the outer peripheral surface of the elastic member, with respect to a region corresponding to ½ of the entire circumferential length of the inner periphery of the annular thin portion including the center portion. As a result, the annular thin portion can be pressed from the inside by at least a pair of protrusions and a location in the vicinity of the central portion of the elastic member, so that the annular thin portion is more uniform radially outward over the entire circumference. Can be elastically deformed.

  The first shaft may have an abutting portion with which the end of the elastic member abuts on the side of the annular thin portion close to the central portion of the first shaft. Thereby, when providing an elastic member inside a cyclic | annular thin part, positioning in an axial direction becomes easy and workability | operativity at the time of an assembly can be improved.

  The first shaft may be made of an aluminum alloy. Thereby, weight reduction can be achieved. In addition, the spring constant of the elastic member necessary to elastically deform the annular thin portion by a desired amount compared to the iron-based alloy can be suppressed, and the elastic member can be reduced in size and weight, Workability at the time of assembly can be improved.

  According to the present invention, a steering shaft with less play can be provided with a simple configuration.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

  First, a description will be given of a steering apparatus that suitably employs a shaft coupling structure according to the present invention. FIG. 1 is an external view for explaining a part of the steering apparatus according to the present embodiment. The steering device 10 includes a steering wheel 12, a steering shaft 14, a steering column 16, a universal joint (not shown), and the like. The steering wheel 12 includes an annular rim 12a, a hub 12b inserted into the steering shaft 14, and spokes 12c connecting the rim 12a and the hub 12b, and is rotated by a driver to steer the vehicle. The steering shaft 14 has a role in which the steering wheel 12 is fixed to the upper end side with a nut 14a and transmits the rotational force of the steering wheel 12, and the steering wheel 12 and the steering shaft 14 are configured to rotate simultaneously.

  The steering column 16 includes an outer tube (outer cylinder) 18 and an inner tube (inner cylinder) 20. The outer tube 18 is fixed to a vehicle frame or the like via a mounting bracket 38. Further, the fixed side of the steering wheel 12 of the steering column 16 is covered with a column cover 22. Various switches (not shown) such as an ignition key switch are arranged on the column cover 22. The steering column 16 is provided with a tilt mechanism (described later), a telescopic mechanism, and the like.

  FIG. 2 is a side view showing the appearance of the steering column 16. The steering shaft 14 includes an upper shaft 30 and a lower shaft 32, and is configured to be able to extend and contract and transmit torque in the column axis direction. The steering column 16 rotatably supports the steering shaft 14.

  The upper shaft 30 is supported so as to be rotatable and non-movable in the column axial direction via a bearing (not shown) with respect to the outer tube 18 so that the steering wheel 12 is assembled to be integrally rotatable at the right end in the drawing. It has become. On the other hand, the lower shaft 32 is rotatably supported by the inner tube 20 via a bearing (not shown), and is an intermediate shaft (both not shown) that can extend and contract and transmit torque via a universal joint at the left end in the figure. ). The intermediate shaft is connected to a steering gear box (both not shown) via a universal joint.

  The outer tube 18 is fitted and connected to the upper end portion of the inner tube 20 at the lower end portion so as to be slidable in the column axial direction, and the upper support that can be tilted and telescopically adjusted by the column side bracket 34 fixed to the lower end portion. It is assembled to a vehicle body side bracket fixed to a part of the vehicle body (not shown) via the mechanism A. The column side bracket 34 is fixed so as to be integrated with the outer tube 18 and constitutes a part of the steering column 16. Further, the inner tube 20 is assembled to a part of the vehicle body (not shown) via a lower support mechanism B that can be rotated by a mounting bracket 36 fixed to the lower end portion.

  The upper support mechanism A allows and regulates the tilting of the steering column 16 and allows the tilting angle of the steering wheel 12 assembled to the upper shaft 30 to be adjusted, and the columnar expansion and contraction of the steering shaft 14 and the steering column 16 in the column axial direction. A telescopic mechanism that can be permitted and regulated and that can adjust the position of the steering wheel 12 in the column axial direction is integrally provided.

  The upper support mechanism A includes a mounting bracket 38 that is assembled to the vehicle body side bracket so as to be movable forward and backward, and the column side bracket 34 can be fixed to and released from the mounting bracket 38 (tilt adjustment is possible in the released state). And a fastening bolt 40 that can be telescopically adjusted, an operation lever 37, a thrust bearing, a cam plate, a nut, a collar, an eccentric cam (both not shown), and the like.

  The mounting bracket 38 supports the column side bracket 34 so that it can tilt in the vertical direction (tiltable) and move in the column axis direction (telescopically possible), and has a pair of left and right arms 42. A pair of mounting portions 60 are provided at the upper side, and the slits provided in these mounting portions 60 are assembled to the vehicle body side brackets using mounting bolts via resin capsules and metal collars.

  The fastening bolt 40 is inserted into a pair of left and right arc-shaped insertion holes provided in both arms 42 of the mounting bracket 38 and a pair of left and right linear insertion holes provided in the column side bracket 34. The arc-shaped insertion holes of both arms 42 are arc-shaped tilt long holes centered on the rotation center of the lower support mechanism B shown in FIG. 1, and allow tilt adjustment. The linear insertion hole of the column side bracket 34 is a linear telescopic long hole formed along the column axial direction, and enables telescopic adjustment. The operation lever 37 is coupled to the head of the fastening bolt 40 using a coupling plate 37a.

  The lower support mechanism B supports the inner tube 20 in the steering column 16 so as to be able to tilt (rotate), and is rotatably fitted in a mounting hole 72 formed in the bracket 36 fixed to the lower end portion of the inner tube 20. And a bolt and a nut (not shown) for fixing the collar 70 to a part (not shown) of the vehicle body.

  FIG. 3 is a partially broken sectional view of the steering shaft 14 according to the present embodiment. FIG. 4 is a cross-sectional view of the lower shaft 32. The steering shaft coupling structure according to the present embodiment includes a lower shaft 32, an upper shaft 30 having a hollow portion into which the lower shaft 32 can be inserted, and an elastic member 44.

  The lower shaft 32 is connected to an intermediate shaft capable of expanding and contracting and transmitting torque via a universal joint, and an end 32a opposite to the left end in the figure is hollow. In other words, the lower shaft 32 has an annular thin portion 32c in which an end portion 32a of the portion inserted into the upper shaft 30 is formed thinner than the central portion 32b over the entire circumference.

  The lower shaft 32 according to the present embodiment has a solid central part 32b thicker than the annular thin part 32c, but is not limited to this, and the central part 32b is thicker than the annular thin part 32c. You may have a certain hollow cylinder shape. The lower shaft 32 is processed into a so-called serration shape in which a plurality of grooves 32d extending linearly in the axial direction of the outer peripheral surface are formed in the circumferential direction. The groove on the outer peripheral surface of the lower shaft 32 may be processed into a spline shape.

  On the other hand, the upper shaft 30 is provided with an opening 30a at the left end in the drawing opposite to the right end in the drawing, which is assembled to the steering wheel 12 so as to be integrally rotatable, and at least the opening portion so that the lower shaft 32 can be inserted. The predetermined length from 30a is hollow. Further, a convex portion that extends linearly in the axial direction from the opening 30a to a predetermined length so as to be fitted to a groove 32d formed on the outer peripheral surface of the lower shaft 32, on the inner peripheral surface of the upper shaft 30. A plurality of 30b are formed in the circumferential direction.

  Therefore, in the shaft coupling structure according to the present embodiment, since the convex portion 30b of the upper shaft 30 fits into the groove 32d of the lower shaft 32, it fits so as not to rotate in the circumferential direction and to slide in the axial direction. Will be combined.

  Fig.5 (a) is XX sectional drawing of FIG. FIG.5 (b) is sectional drawing to which the B area | region of Fig.5 (a) was expanded. FIG. 6 is a perspective view showing the appearance of the elastic member 44. The elastic member 44 is provided inside the annular thin portion 32c while being bent so as to press the inner peripheral surface of the annular thin portion 32c in the radial direction. The annular thin portion 32c is configured to be elastically deformable when pressed toward the outer side in the radial direction by the elastic member 44 that is bent.

  Therefore, when the annular thin portion 32c is pressed from the inner side toward the outer side in the radial direction by the elastic member 44 in a state where the lower shaft 32 is inserted into the upper shaft 30, at least the end portion of the lower shaft 32 faces toward the outer side. Due to elastic deformation, the lower shaft 32 is more closely attached to the upper shaft 30. Therefore, even if a slight gap is generated between the upper shaft 30 and the lower shaft 32, the annular thin portion 32c formed at the end of the lower shaft 32 spreads radially outward, so that Generation of backlash in the rotational direction of the upper shaft 30 is suppressed. Further, since the annular thin portion 32c is provided at the end of the lower shaft 32, the lower shaft 32 can be easily processed.

  The elastic member 44 according to the present embodiment is a cylindrical clip spring having a U-shaped cross-section when viewed from the axial direction of the lower shaft 32, and a cutout portion 44a in which a part thereof is cutout in the axial direction. have.

  Therefore, for example, an elastic member having a simple configuration can be manufactured by a simple method of deforming a plate-like member into a cylindrical shape, so that the manufacturing cost can be reduced. Moreover, the elastic member 44 can be easily bent by bringing both end portions 44b sandwiching the notch portion 44a closer, and workability when the elastic member 44 is attached to the annular thin portion 32c can be improved.

  The elastic member 44 has an outer circumferential length L1 (see FIG. 6) that is longer than ½ of the circumferential total length L2 of the annular thin portion 32c, that is, more than half the circumferential length. The width of the notch 44a is set so as to be longer. Therefore, it is possible to reduce the elastic member 44 from being displaced or deviated from a predetermined position inside the annular thin portion 32c.

  The elastic member 44 has a pair of protrusions 44c formed on the outer peripheral surface thereof. For this reason, even if the elastic member 44 and the annular thin portion 32c are not finished with high processing accuracy, variation in the location where the annular thin portion 32c is pressed by the elastic member 44 is reduced, and the annular thin portion corresponding to the position of the protrusion 44c. A desired portion inside 32c is stably pressed, and the annular thin portion 32c is easily elastically deformed as designed. As a result, even if there is a slight gap between the upper shaft 30 and the lower shaft 32, the end portion of the lower shaft 32 is widened to suppress the occurrence of play in the rotational direction of the upper shaft 30 relative to the lower shaft 32. can do.

  The optimum value of the thickness of the annular thin portion 32c, the shape of the elastic member 44, and the spring constant is the amount of elastic deformation when the annular thin portion 32c is pressed outward in the radial direction by the bent elastic member 44. Can be set by experiment in consideration of the diameter of the steering shaft 14, the design tolerance of each component, and the material.

  For example, when the material of the lower shaft 32 is an aluminum alloy, not only the weight of the lower shaft 32 itself is reduced, but also the elastic member 44 necessary for elastically deforming the annular thin portion 32c by a desired amount as compared with an iron-based alloy. The spring constant of can be kept low. Therefore, the elastic member 44 can be reduced in size and weight, and the elastic member 44 can be easily bent at the time of assembly, thereby improving workability.

  The protrusion 44c according to the present embodiment has both end portions 44b of the outer peripheral surface of the elastic member 44 more than the region corresponding to 1/2 of the entire circumferential length L2 of the inner peripheral portion of the annular thin portion 32c including the central portion 44d. Each is formed on the side. As a result, the elastic member 44 has a downward force due to the reaction force of the pair of protrusions 44c pressing the inner peripheral surface of the annular thin portion 32c, and the central portion 44d of the elastic member 44 presses the inner side of the annular thin portion 32c. It becomes possible to do.

  Therefore, the elastic member 44 can press the annular thin portion 32c from the inside by at least the pair of protrusions 44c and the contact portion in the vicinity of the central portion 44d of the elastic member 44, and the annular thin portion 32c has a diameter over the entire circumference. It can be elastically deformed more uniformly toward the outside in the direction. As a result, the occurrence of backlash between the lower shaft 32 and the upper shaft 30 when the steering shaft 14 is rotated is further reduced.

  As shown in FIG. 4, the lower shaft 32 has an abutting portion 32 e against which the end of the elastic member 44 abuts on the side of the annular thin portion 32 c close to the center portion 32 b of the lower shaft 32. Thereby, when providing the elastic member 44 inside the annular thin part 32c, the axial positioning becomes easy, and the workability at the time of assembly can be improved. The lower shaft 32 is set so that the distance D1 from the abutting portion 32e to the opening 32f of the lower shaft is larger than the distance D2 from the end of the elastic member 44 to the protrusion 44c.

  Thus, when the elastic member 44 is mounted inside the annular thin portion 32c, it is not necessary to adjust the projection 44c so as to press a desired position on the inner peripheral surface of the annular thin portion 32c. Can be improved. The protrusion 44c is formed so as to be positioned in the vicinity of the opening 32f in a state where the elastic member 44 is mounted inside the annular thin portion 32c. As a result, the spring force required to elastically deform the annular thin portion 32c by a predetermined amount can be suppressed, and the plate thickness of the elastic member 44 can be reduced, and the weight and cost can be reduced. In addition, since the elastic member 44 can be easily bent, workability can be improved.

  As described above, the present invention has been described with reference to the above-described embodiment. However, the present invention is not limited to the above-described embodiment, and the present invention can be appropriately combined or replaced with the configuration of the embodiment. It is included in the present invention. In addition, it is possible to appropriately change the combination and order of the processes in the embodiment based on the knowledge of those skilled in the art and to add various modifications such as various design changes to the embodiment. The described embodiments can also be included in the scope of the present invention.

  For example, the elastic member 44 of the present embodiment may be an annular spring as well as a cylindrical spring. As a result, the structure is simplified compared to the case of a cylindrical shape, and the manufacturing cost can be reduced due to the ease of manufacturing and the reduction in the amount of material due to downsizing. Further, the protrusions 44c formed on the elastic member 44 are not limited to a pair formed on the same plane perpendicular to the axis, and a plurality of pairs may be formed in the axial direction, or separate from each other perpendicular to the axis. It may be formed on each plane.

It is an external view for demonstrating a part of steering apparatus which concerns on this Embodiment. It is a side view which shows the external appearance of a steering column. It is a partially broken sectional view of the steering shaft according to the present embodiment. It is sectional drawing of a lower shaft. Fig.5 (a) is XX sectional drawing of FIG. FIG.5 (b) is sectional drawing to which the B area | region of Fig.5 (a) was expanded. It is a perspective view which shows the external appearance of an elastic member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Steering device, 14 Steering shaft, 16 Steering column, 18 Outer tube, 20 Inner tube, 30 Upper shaft, 30a Opening part, 30b Convex part, 32 Lower shaft, 32a End part, 32b Center part, 32c Annular thin part, 32d Groove, 32e butting portion, 32f opening, 44 elastic member, 44a notch, 44b both ends, 44c protrusion, 44d center.

Claims (9)

A first shaft;
A second shaft having a hollow part into which the first shaft can be inserted, and
A shaft coupling structure in which the first shaft and the second shaft are fitted to each other so as to be non-rotatable in the circumferential direction and slidable in the axial direction;
The first shaft has an annular thin portion in which an end portion of the portion inserted into the second shaft is formed thinner than the central portion over the entire circumference, and an inner peripheral surface of the annular thin portion is radially oriented. And an elastic member bent to press
A shaft coupling structure, wherein the annular thin portion is configured to be elastically deformed when pressed toward the outside in the radial direction by the elastic member being bent. The first shaft has a plurality of grooves extending linearly in the axial direction of the outer peripheral surface thereof in the circumferential direction.
2. The shaft according to claim 1, wherein the second shaft is formed with a plurality of convex portions extending in a straight line in an axial direction of an inner peripheral surface thereof and fitted in the groove in the circumferential direction. Bond structure.   3. The shaft coupling structure according to claim 1, wherein the elastic member is an annular member, and has a cutout part of which is cut out in the axial direction. 4.   4. The shaft coupling structure according to claim 3, wherein the elastic member has a circumferential length of an outer circumference longer than a half of a total length of the inner circumference of the annular thin portion in the circumferential direction.   5. The shaft coupling structure according to claim 3, wherein the elastic member is a cylindrical spring having a U-shaped cross section when viewed from the axial direction of the first shaft.   The shaft coupling structure according to claim 5, wherein the elastic member has a protrusion formed on an outer peripheral surface thereof.   The protrusions are formed on both ends of the outer peripheral surface of the elastic member, with respect to a region corresponding to 1/2 of the entire circumferential length of the inner periphery of the annular thin portion including the center portion. The shaft coupling structure according to claim 6.   The said 1st shaft has an abutting part which the edge part of the said elastic member abuts on the side near the center part of this 1st shaft of the said annular thin part, The any one of Claim 1 thru | or 7 characterized by the above-mentioned. The shaft coupling structure described in 1.   9. The shaft coupling structure according to claim 1, wherein the first shaft is made of an aluminum alloy.

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