JP2009197825A - Telescopic shaft and steering device equipped with telescopic shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a telescopic shaft and a steering device equipped with the telescopic shaft preventing manufacturing cost increase of a flat spring extended in an axial direction exceeding extension and contraction distance in normal use in an telescopic shaft enabling rolling elements to roll even if the telescopic shaft extends and contracts exceeding the extension and contraction range in normal use. <P>SOLUTION: Since a parallel extension part 711 is formed in a flat plate shape perpendicular to a normal line 161 passing through an axial center of a male intermediate shaft 16A, pre-load in a radial direction is applied and pre-load in a rotary direction is not applied. Consequently, a shape of the extension part 71 is a simple flat plate shape since it is sufficient to apply only radial direction pre-load necessary for smooth rolling without a play on balls 55. Since axial length of a complicated shape part necessarily accurately manufactured is same as conventional shaft, manufacturing of the flat spring is facilitated, addition of correction process of the flat spring is not necessary, and manufacturing cost increase of the flat spring is suppressed to the minimum. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a steering device, and more particularly to a steering device having a telescopic shaft capable of transmitting rotational torque and relatively moving in an axial direction, for example, a telescopic shaft such as an intermediate shaft or a steering shaft.

  A telescopic shaft connected to the steering device so as to be able to transmit rotational torque and to be relatively movable in the axial direction is incorporated as an intermediate shaft, a steering shaft, or the like. That is, when the universal joint is fastened to the pinion shaft that meshes with the rack shaft of the steering gear, the intermediate shaft needs to have a telescopic function in order to be contracted once and then fitted to the pinion shaft and fastened.

  In addition, since the steering shaft needs to adjust the position of the steering wheel in the axial direction according to the physique and driving posture of the driver, an expansion / contraction function is required. As such an expansion / contraction axis, an expansion / contraction axis of a non-circular ball structure disclosed in Patent Document 1 is common.

  The telescopic shaft disclosed in Patent Document 1 includes a plurality of balls (between a male shaft side axial groove formed on the outer periphery of the male shaft and a female shaft side axial groove formed on the inner periphery of the female shaft. The rolling element is fitted so that the ball rolls when the male shaft and the female shaft extend and contract so that the intermediate shaft can smoothly expand and contract.

  Also, a leaf spring is inserted in a compressed state between the ball and the male shaft side axial groove, and between the male shaft side axial groove, the ball and the female shaft side axial groove, the rotational direction and radius Both directions of preload are applied. As a result, the rigidity in the rotational direction and the radial direction is ensured between the female shaft and the male shaft so that a good steering feeling can be obtained.

  In the telescopic shaft of such a non-circular ball structure of Patent Document 1, the ball moves in the axial direction along the male shaft side axial groove of the male shaft while rolling when the telescopic shaft expands and contracts. Therefore, the axial length of the male shaft side axial groove of the male shaft needs to be a length obtained by adding the axial movement length of the ball to the axial length for accommodating the ball. Therefore, the axial length of the male shaft side axial groove and the axial length of the leaf spring are determined according to the expansion / contraction distance during normal use.

  When assembling the steering device to the vehicle body, the intermediate shaft is extended and extended beyond the normal extension distance to fit the pinion shaft that meshes with the rack shaft of the steering gear. It is necessary to tie it together.

  When the intermediate shaft extends and contracts beyond the expansion / contraction distance during normal use, the ball slides in the male shaft side axial groove and in the female shaft side axial groove. Therefore, the frictional force becomes large, and a large force is required to extend and contract the intermediate shaft, which causes a problem that the assembling work becomes difficult.

  In order to allow the ball to roll even if the intermediate shaft is expanded and contracted beyond the expansion / contraction distance during normal use, the axial length of the male shaft side axial groove and the axial length of the leaf spring are required. Both need to be long. However, in order to apply both rotational and radial preloads between the female shaft and the male shaft, the leaf spring has a complicated shape. Therefore, if the length of the plate spring in the axial direction becomes long, it becomes difficult to manufacture the plate spring with high accuracy, so that a plate spring correction process is added, which increases the manufacturing cost of the plate spring. There was a fear.

JP 2004-130928 A

  The present invention relates to a leaf spring that extends in the axial direction beyond the expansion / contraction distance during normal use in the expansion / contraction shaft in which the rolling element rolls even if the expansion / contraction shaft extends or contracts beyond the expansion / contraction range during normal use. It is an object of the present invention to provide a telescopic shaft and a steering device provided with the telescopic shaft so that the manufacturing cost is not excessively increased.

  The above problem is solved by the following means. That is, the first invention is a male shaft, a male shaft side axial groove formed on the outer periphery of the male shaft, and a female that is externally fitted to the male shaft so as to be capable of relative movement in the axial direction and to transmit rotational torque. A female shaft side axial groove formed on the inner periphery of the shaft and the female shaft at the same phase position as the male shaft side axial groove, and between the male shaft side axial groove and the female shaft side axial groove. , A plurality of rolling elements inserted so as to be capable of rolling in the axial direction, inserted between the rolling elements and the male shaft side axial groove, and through the rolling elements, the male shaft side axial groove and the female shaft side A leaf spring for applying a preload between the axial groove and each of the leaf springs in contact with a side surface facing the circumferential direction of the rolling element, and the rolling element in both a radial direction and a rotational direction; A pair of rolling element side contact portions for applying preload, the pair of rolling elements A pair of groove side contact portions that are respectively spaced apart from each other by a predetermined distance in the circumferential direction with respect to the body side contact portion, and that contact each side surface of the male shaft side axial groove, the rolling element side contact portion and the groove side surface A pair of urging parts that connect the outer ends in the radial direction of the side contact parts and elastically urge the rolling element side contact part and the groove side contact part in a direction away from each other, the pair of rolling element side contacts A connecting portion that connects a radially inner end of each portion and is in contact with a bottom surface of the male shaft side axial groove, and is separated from the radially inner end of the rolling element by a predetermined distance radially inward; Is formed extending in the axial direction from the bottom surface of the male shaft side axial groove, and is arranged to be in contact with the inner end in the radial direction of the rolling element. It is an expansion-contraction axis | shaft characterized by including the extension part which provides only the preload of this.

  A second aspect of the invention is the telescopic shaft according to the first aspect of the invention, wherein the extension end in the axial direction of the extension portion contacts the bottom surface of the male shaft side axial groove.

  According to a third aspect of the invention, in the telescopic shaft of the second aspect of the invention, a folded portion that contacts the bottom surface of the male shaft side axial groove is formed at the axial extension end of the extension portion. It is a characteristic telescopic shaft.

  According to a fourth aspect of the present invention, in the telescopic shaft of the second aspect of the present invention, a projecting portion that protrudes outward in the radial direction formed on the bottom surface of the male shaft side axial groove is an axial extension end of the extension portion. It is an expansion-contraction shaft characterized by contacting.

  According to a fifth invention, in the telescopic shaft according to any one of the second to fourth inventions, the extension portion is formed by extending in the axial direction parallel to the bottom surface of the male shaft side axial groove. The telescopic shaft is provided with a parallel extending portion and an inclined extending portion that smoothly connects the boundary between the connecting portion and the parallel extending portion.

  According to a sixth aspect of the invention, in the telescopic shaft of the fifth aspect, the inclined extension portion is formed in a mountain shape having a vertex protruding radially outward from the radially outer end of the parallel extension portion. The telescopic shaft characterized by the following.

  According to a seventh invention, in the telescopic shaft according to any one of the first to sixth inventions, the male shaft side female groove and the male shaft side axial groove and the female shaft side are provided in the fitting portion between the male shaft and the female shaft. At least a pair of another male shaft side axial groove and a female shaft side axial groove is formed at a phase position different from that of the axial groove, and this at least a pair of another male shaft side axial groove and female shaft side axial direction is formed. A cylindrical pin for transmitting a rotational torque between the male shaft and the female shaft is inserted into the groove, and the shaft is a telescopic shaft.

  An eighth aspect of the present invention is a steering apparatus including the telescopic shaft according to any one of the first to seventh aspects.

  In the telescopic shaft and steering device of the present invention, the male shaft side axial groove formed on the outer periphery of the male shaft and the female shaft side formed on the inner periphery of the female shaft at the same phase position as the male shaft side axial groove A plurality of rolling elements inserted between the axial groove, the male shaft side axial groove and the female shaft side axial groove so as to roll in the axial direction, and the rolling element and the male shaft side axial groove It has a leaf spring interposed between the male shaft side axial groove and the female shaft side axial groove via a rolling element.

The leaf springs are in contact with the circumferentially opposed side surfaces of the rolling elements, respectively, and a pair of rolling element side contact portions that apply both radial and rotational preloads to the rolling elements, and a pair of rolling elements. A pair of groove side contact portions that are respectively spaced apart from each other by a predetermined distance in the circumferential direction with respect to the moving body side contact portion, and that respectively contact the side surfaces of the male shaft side axial groove, and the rolling element side contact portion and the groove side surface A pair of urging portions that elastically urge the rolling element side contact portion and the groove side surface contact portion in directions away from each other, and a pair of rolling element side contacts. Connecting a radial inner end of each part, contacting the bottom surface of the axial groove on the male shaft side, and being spaced apart from the radial inner end of the rolling element by a predetermined distance radially inward. Formed extending in the direction, with a gap between the bottom of the axial groove on the male shaft side. Rolling contactable radially inner end of the body includes an extension portion that applies only preload in the radial direction to the rolling element.

  Therefore, the shape of the extension part of the leaf spring that extends in the axial direction beyond the expansion / contraction distance during normal use is simple, and the rolling element side contact part, biasing part, groove side contact part, connecting part, etc. are accurate. It is necessary to manufacture, and the length of the complicated shape portion in the axial direction may be the same as the conventional one. Therefore, it is easy to manufacture the leaf spring, and it is not necessary to add a plate spring correction process, and an increase in the leaf spring manufacturing cost can be minimized.

  Embodiments 1 to 6 of the present invention will be described below with reference to the drawings.

  FIG. 1 is an overall side view of a steering apparatus according to the present invention, and is a partially sectional side view showing an embodiment applied to an electric power steering apparatus having a steering assisting portion. FIG. 2 is an enlarged view of the main part of FIG. 1 showing the steering apparatus according to the first embodiment of the present invention, and is an enlarged vertical sectional view showing an example applied to the expansion / contraction part of the intermediate shaft.

  3 (1) is an AA enlarged sectional view of FIG. 2, and FIG. 3 (2) is an enlarged sectional view of the vicinity of the axial groove 54 of FIG. 3 (1). 4A is an enlarged cross-sectional view taken along the line BB in FIG. 2, and FIG. 4B is an enlarged cross-sectional view in the vicinity of the axial groove 54 in FIG. FIG. 5 is a perspective view showing a leaf spring according to the first embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view of a portion P in FIG.

  As shown in FIG. 1, the steering device of the present invention includes a steering shaft 12 on which a steering wheel 11 can be mounted on the rear side of the vehicle body (right side of FIG. 1), a steering column 13 inserted through the steering shaft 12, and the steering wheel. An assist device (steering assisting portion) 20 for applying assist torque to the shaft 12 and a steering gear connected to the front side of the vehicle body of the steering shaft 12 (left side in FIG. 1) via a rack / pinion mechanism (not shown). 30.

  The steering shaft 12 is spline-fitted between a female steering shaft 12A and a male steering shaft 12B so as to be able to transmit rotational torque and to be relatively movable in the axial direction. Therefore, when the female steering shaft 12A and the male steering shaft 12B collide, the spline fitting portion moves relative to each other so that the total length can be shortened.

  Further, the cylindrical steering column 13 inserted through the steering shaft 12 has a so-called collapsible structure. That is, the outer column 13A and the inner column 13B are combined so as to be telescopically movable, and when an impact in the axial direction is applied at the time of collision, the entire length is shortened while absorbing energy due to the impact.

  The vehicle body front side end portion of the inner column 13B is press-fitted and fixed to the vehicle body rear side end portion of the gear housing 21. Further, the front end portion of the male steering shaft 12B on the vehicle body is passed through the inside of the gear housing 21 and connected to the rear end portion of the assist device 20 on the rear side of the input shaft (not shown).

  The steering column 13 is supported by a support bracket 14 at a middle portion thereof on a part of the vehicle body 18 such as a lower surface of the dashboard. Further, a locking portion (not shown) is provided between the support bracket 14 and the vehicle body 18, and when an impact in a direction toward the front side of the vehicle body is applied to the support bracket 14, the support bracket 14 is locked to the locking bracket 14. It moves away from the vehicle and moves to the front side of the vehicle.

  The upper end portion of the gear housing 21 is also supported on a part of the vehicle body 18. In this embodiment, the height position of the steering wheel 11 and the longitudinal position of the vehicle body can be freely adjusted by providing a tilt mechanism and a telescopic mechanism. Such a tilt mechanism and a telescopic mechanism are well known in the art and are not characteristic features of the present invention, and thus detailed description thereof is omitted.

  The output shaft 23 protruding from the end face on the front side of the vehicle body of the gear housing 21 is connected to the rear end portion of the intermediate shaft 16 via the universal joint 15. Further, the input shaft 31 of the steering gear 30 is connected to the front end portion of the intermediate shaft 16 via another universal joint 17. The intermediate shaft 16 is fitted on the vehicle body front side of the male intermediate shaft (male shaft) 16A on the vehicle body rear side of the female intermediate shaft (female shaft) 16B, so that rotational torque can be transmitted and relative movement in the axial direction is possible. Is fitted.

  A pinion (not shown) is coupled to the vehicle body front side of the input shaft 31. A rack (not shown) fitted in the steering gear 30 so as to be reciprocally slidable meshes with the pinion, and the rotation of the steering wheel 11 moves the tie rod 32 to steer a wheel (not shown).

  A case 261 of an electric motor 26 is fixed to the gear housing 21 of the assist device 20, and a worm is coupled to a rotating shaft (not shown) of the electric motor 26. A worm wheel (not shown) is attached to the output shaft 23, and the worm of the rotating shaft of the electric motor 26 is engaged with the worm wheel.

  A torque sensor (not shown) is provided around an intermediate portion of the axial length of the output shaft 23. The direction and magnitude of torque applied from the steering wheel 11 to the steering shaft 12 is detected by a torque sensor.

  The electric motor 26 is driven according to the detected value of the torque sensor, and auxiliary torque is generated in a predetermined direction in a predetermined direction on the output shaft 23 via a speed reduction mechanism composed of a worm and a worm wheel. The assist device 20 is not limited to an electric assist device, and may be a hydraulic assist device provided in the steering gear 30 or the like.

  2 to 6 show the connecting portion of the telescopic shaft according to the first embodiment of the present invention, and shows an example applied to the connecting portion between the male intermediate shaft 16A and the female intermediate shaft 16B of the intermediate shaft 16 of FIG.

  As shown in FIGS. 2 to 6, the vehicle rear side (right side in FIG. 2) of the female intermediate shaft (female shaft) 16B is outside the vehicle front side (left side in FIG. 2) of the male intermediate shaft (male shaft) 16A. It is fitted and connected. The female intermediate shaft 16B is formed in a hollow cylindrical shape, and an axial groove 41 (female shaft side axial groove) 41 having a substantially semicircular cross section at the axis perpendicular to the inner periphery of the inner diameter hole 40 has a telescopic stroke. Six pieces are formed at equal intervals (60-degree intervals) over the entire length.

  The front side of the vehicle body of the male intermediate shaft 16A is formed in a solid cylindrical shape. From the front side of the vehicle body, a large diameter shaft portion 50 having a large diameter and a diameter smaller than that of the large diameter shaft portion 50 are formed. The small-diameter shaft portions 51 are formed in this order.

  A small-diameter cylindrical portion 44 is formed at the vehicle body rear end of the female intermediate shaft 16B, and an inner periphery 421 of a thin cylindrical wiper mounting plate 42 is press-fitted into an outer periphery 441 of the small-diameter cylindrical portion 44. The wiper mounting plate 42 is bent in an L shape toward the axial center of the male intermediate shaft 16A at the vehicle body rear side end surface 442 of the small diameter cylindrical portion 44 to form a bent portion 422.

  A wiper 43 made of rubber or the like is fixed to the bent portion 422. The wiper 43 slides on the outer periphery 511 of the small-diameter shaft portion 51, and dust is generated in the fitting portion between the female intermediate shaft 16B and the male intermediate shaft 16A. Prevents intrusion. The wiper mounting plate 42 is manufactured by pressing a thin steel plate and presses the front end of the vehicle body on the inner periphery 421 of the wiper mounting plate 42 into the outer periphery 441 of the small diameter cylindrical portion 44.

  On the outer periphery of the large diameter shaft portion 50 of the male intermediate shaft 16 </ b> A, three axial grooves (male shaft side axial grooves) 54 having a substantially trapezoidal cross section at the right angle are provided on the front end 501 of the large diameter shaft portion 50. Are formed at equal intervals (120 degree intervals) over substantially the entire axial length of the large-diameter shaft portion 50. The axial groove 54 having a substantially trapezoidal cross section at right angles to the axis is for ball rolling.

  As shown in FIG. 2, the axial length of the axial groove 54 for rolling the ball is formed to be a length L3 that is obtained by adding a length L1 and a length L2. That is, the length L1 is the length in the axial direction necessary for the ball 55 as the rolling element to roll in a telescopic motion during a normal driving operation. The length L2 is an axial length necessary for the ball 55 to roll when the intermediate shaft 16 is contracted beyond the contraction distance during normal driving operation when the steering device is assembled.

  In a space formed by the three axial grooves 54 for ball rolling and the three axial grooves 41 of the female intermediate shaft 16B in the same phase, a plurality of spherical balls (5 balls) as rolling elements 55 are respectively inserted.

  A disc-shaped washer 58, a disc-shaped spring plate 59, and a disc-shaped washer 60 are provided on the small-diameter shaft portion 57 formed at the front end 501 of the large-diameter portion 50 of the male intermediate shaft 16A from the rear side of the vehicle body. They are fitted in order. The front end of the vehicle body of the small-diameter shaft portion 57 is crimped, and a spring plate 59 applies a biasing force toward the vehicle rear side (right side in FIG. 2) to the washer 58 on the vehicle rear side.

  Further, on the outer periphery of the large-diameter shaft portion 50 of the male intermediate shaft 16A, three axial grooves (male shaft-side axial grooves) 52 having a substantially semicircular cross section are arranged at equal intervals (120 degree intervals). Is formed. The axial groove 52 is formed at the intermediate position between the three axial grooves 54 and 54 for ball rolling, and has the same length L3 as the axial length L3 of the axial groove 54.

  In a cylindrical space formed by the three axial grooves 52 of the male intermediate shaft 16A and the three axial grooves 41 of the female intermediate shaft 16B in the same phase as the axial groove 52, rotational torque is generated. Solid cylindrical pins (needle rollers) 53A and 53B are inserted as transmission members. The cylindrical pins 53A and 53B have a cylindrical shape formed by the axial groove 52 and the axial groove 41, with one cylindrical pin 53A being disposed on the front side of the vehicle body and the other cylindrical pin 53B being disposed on the rear side of the vehicle body. It is inserted in series in the space.

  The columnar pins 53A and 53B are the same parts having the same length in the axial direction, and the length L4 from the vehicle body front end of the columnar pin 53A to the vehicle body rear end of the columnar pin 53B is the axis. The directional groove 52 is formed slightly longer than the axial length L3.

  The outer diameter of the cylindrical pins 53A and 53B is slightly larger than the inner diameter of the cylindrical space formed by the axial groove 52 of the male intermediate shaft 16A and the axial groove 41 of the female intermediate shaft 16B. It has a small diameter.

  The end surface of the washer 58 on the vehicle body rear side is in contact with the vehicle body front end of the cylindrical pin 53A, and has a function as a regulating member that regulates the axial movement of the cylindrical pins 53A and 53B. A wall 521 perpendicular to the axis of the male intermediate shaft 16A is formed at the rear end of the axial groove 52 in the vehicle body, and receives the rear end of the cylindrical pin 53B. In addition, the vehicle body rear end and the vehicle body front end of the cylindrical pins 53A and 53B have a crowning or tapered shape and are reduced in diameter toward the end side.

  A leaf spring (biasing member) 56 as a preload application member is inserted between the three substantially trapezoidal axial grooves 54 and the ball 55. As shown in detail in FIG. 3 (2), the axial groove 54 is composed of a bottom surface 541 wider than the diameter of the ball 55 and side surfaces 542 and 542 extending upward in a V shape from both ends of the bottom surface 541. ing. The bottom surface 541 is formed orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A as viewed in the cross-section perpendicular to the axis in FIG.

  The leaf spring 56 is substantially parallel to the side surfaces 542 and 542 of the axial groove 54, extends upward in a V shape from the bottom surface 541, and a pair of rolling element side contact portions 562 and 562 that respectively contact the ball 55, and the rolling element side It is comprised by the connection part 561 which connects the radial direction inner end of the contact parts 562 and 562. FIG. The connecting portion 561 is in contact with the bottom surface 541 of the axial groove 54 and is spaced a predetermined distance radially inward from the radially inner end of the ball 55.

  In addition, a pair of urging portions 563 and 563 are formed at the upper ends of the rolling element side contact portions 562 and 562, respectively, which are bent outward in a circular arc shape. Groove side contact portions 564 and 564 extending downward from the biasing portions 563 and 563 toward the bottom surface 541 are formed, and the groove side contact portions 564 and 564 abut against the side surface 542 of the axial groove 54. ing. The urging portions 563 and 563 elastically urge the rolling element side contact portions 562 and 562 and the groove side surface contact portions 564 and 564 in a direction away from each other.

  As shown in FIG. 2, the axial lengths of the rolling element side contact portions 562 and 562, the biasing portions 563 and 563, the groove side surface side contact portions 564 and 564, and the connecting portion 561 of the leaf spring 56 are as described above. The axial length 54 of the axial groove 54 is substantially the same as the axial length L1 (the axial length necessary for the ball 55 to roll in a telescopic operation during a normal driving operation).

  The plate spring 56 is inserted between the axial groove 54 and the ball 55 by being elastically deformed with the vehicle body front end 565 matched with the vehicle body front end 501 of the large-diameter shaft portion 50. Accordingly, in the leaf spring 56, the biasing portions 563 and 563 are mainly elastically deformed to absorb the rotational and radial play between the ball 55 and the axial groove 54 and the axial groove 41.

  There are minute gaps between the cylindrical pins 53A, 53B and the axial grooves 41 and 52. When the female intermediate shaft 16B and the male intermediate shaft 16A are relatively displaced by a slight angle in the rotational direction, the cylindrical pins 53A and 53B come into contact with the axial groove 41 and the axial groove 52.

  However, the leaf spring 56 is inserted in a compressed state between the ball 55 and the substantially trapezoidal axial groove 54, and the leaf spring 56 is inserted between the axial groove 54, the ball 55, and the axial groove 41. An urging force (predetermined preload) due to elastic deformation is applied.

  Therefore, there is no play in the rotational direction or radial direction between the female intermediate shaft 16B and the male intermediate shaft 16A. Further, even if there is an eccentricity or inclination between the female intermediate shaft 16B and the male intermediate shaft 16A, it can be absorbed by the elastic force of the leaf spring 56.

  As shown in FIGS. 4 to 6, the connecting portion 561 is formed with an extension portion 71 that extends further from the vehicle body rear end 566 toward the vehicle body rear side. The extension portion 71 has a flat plate shape and is formed orthogonal to a normal line 161 passing through the axis of the male intermediate shaft 16A when viewed in a cross section perpendicular to the axis in FIG. Further, the extension portion 71 is configured from the front side of the vehicle body in the order of the inclined extension portion 712 and the parallel extension portion 711. The extension portion 71 is slightly narrower than the width of the connecting portion 561 and has a constant width W. A length L2 is formed in parallel to the axis of 16A.

  That is, the extension portion 71 has a gap δ1 between the bottom surface 541 of the axial groove 54, a parallel extension portion 711 parallel to the bottom surface 541, a vehicle body front end of the parallel extension portion 711, and a vehicle body of the connecting portion 561. It is comprised by the inclination extension part 712 which connects a back end smoothly. The inclined extension portion 712 smoothly guides the ball 55 rolling along the rolling element side contact portions 562 and 562 of the leaf spring 56 to the parallel extension portion 711.

  A wall 543 orthogonal to the axis of the male intermediate shaft 16 </ b> A is formed at the vehicle body rear end of the axial groove 54, and the vehicle body rear end of the parallel extension 711 is in contact with the wall 543. Further, the parallel extension portion 711 is supported in a cantilever state with the vehicle body rear end 566 of the connecting portion 561 as a fulcrum.

  The parallel extension 711 elastically deforms and contacts the inner end of the ball 55 in the radial direction, and the elastic force of the inclined extension 712 and the parallel extension 711 causes the ball 55 to move with respect to the axial groove 41 of the female shaft 16B. Preload is applied. Since the parallel extension portion 711 is formed in a flat plate shape orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A, it applies only a radial preload and does not apply a rotational preload.

  That is, since the steering wheel 11 is operated during a normal driving operation, rotational torque acts between the ball 55 and the axial groove 54 and the axial groove 41. However, when the telescopic shaft is contracted beyond the contraction distance during normal driving operation, the steering wheel 11 is not operated, so that no rotational torque acts between the ball 55 and the axial groove 54 and the axial groove 41. .

  For this reason, it is sufficient to apply only the radial preload necessary for the ball 55 to roll smoothly and without backlash, so that the shape of the extension 71 may be a simple flat plate. Accordingly, the axial lengths of the complicated shape portions (rolling body side contact portion 562, urging portion 563, groove side surface side contact portion 564, and connecting portion 561) that need to be manufactured with high accuracy can be the same as the conventional length. . Therefore, it is easy to manufacture the leaf spring, and it is not necessary to add a plate spring correction process, and an increase in the leaf spring manufacturing cost can be minimized.

  When the male intermediate shaft 16A is moved (contracted) to the left in FIG. 2 with respect to the female intermediate shaft 16B, the ball 55 rotates clockwise, and the ball 55 rolls along the axial groove 54. Move to the rear (right direction) of the car.

  Further, when the male intermediate shaft 16A is moved to the left in FIG. 2 with respect to the female intermediate shaft 16B and the contraction distance during normal driving operation is exceeded, the rolling elements of the leaf spring 56 are sequentially from the ball 55 at the rearmost end of the vehicle body. The side contact portion 562, the urging portion 563, the groove side contact portion 564, and the connecting portion 561 over the vehicle body rear end 566, ride on the inclined extension portion 712, and are guided by the inclined extension portion 712 to reach the parallel extension portion 711. .

  As a result, as shown by a two-dot chain line in FIGS. 2 and 6, the parallel extension portion 711 is elastically deformed and contacts the radially inner end of the ball 55, and the elastic force of the inclined extension portion 712 and the parallel extension portion 711 is obtained. Thus, a preload is applied to the ball 55 in the radially outward direction with respect to the axial groove 41 of the female shaft 16B.

  Therefore, even when the telescopic shaft is contracted beyond a predetermined contraction distance when the steering device is assembled, a preload having a predetermined size can be applied to the ball 55 with respect to the axial groove 41 of the female shaft 16B. Therefore, a smooth contraction operation without play can be performed.

  Next, after the assembly operation is completed, when the male intermediate shaft 16A is moved in the right direction in FIG. 2 with respect to the female intermediate shaft 16B, the ball 55 rotates counterclockwise, and the ball 55 is moved to the parallel extension 711, While rolling along the axial groove 41, the vehicle moves forward (to the left) in the vehicle body.

  Further, when the male intermediate shaft 16A is moved to the right in FIG. 2 with respect to the female intermediate shaft 16B, the rolling extension side contact portion of the leaf spring 56 is guided to the inclined extension portion 712 in order from the ball 55 at the front end of the vehicle body. 562, the urging portion 563, the groove side surface contact portion 564, and the vehicle body rear end 566 of the connecting portion 561.

  Accordingly, when the assembling work is completed and all of the five balls 55 reach the rolling element side contact portion 562, the urging portion 563, the groove side contact portion 564, and the connecting portion 561 of the leaf spring 56, the normal driving operation is performed. At the time of the expansion / contraction operation, the ball 55 rolls, and the expansion / contraction operation of the intermediate shaft 16 is performed smoothly. Further, the rigidity in the rotational direction and the radial direction between the male intermediate shaft 16A and the female intermediate shaft 16B is ensured, and a good steering feeling can be obtained.

  Next, a second embodiment of the present invention will be described. FIG. 7 is a view corresponding to FIG. 2 showing the expansion / contraction portion of the intermediate shaft according to the second embodiment of the present invention. FIG. 8 is a perspective view showing a leaf spring according to the second embodiment of the present invention. FIG. 9 is an enlarged cross-sectional view of a portion Q in FIG. In the following description, the same structural portion and operation as those of the first embodiment will be described without any duplication. The same parts as those in the first embodiment will be described with the same numbers.

  The second embodiment is a modification of the first embodiment. In the first embodiment, the extension portion 71 is supported in a cantilever state with the vehicle body rear end 566 of the connecting portion 561 as a fulcrum, but the second embodiment is an example in which the extension portion 71 is supported in a both-end support state. . That is, FIGS. 7 to 9 show the connecting part of the telescopic shaft of Example 2 of the present invention, and show an example applied to the connecting part of the male intermediate shaft 16A and the female intermediate shaft 16B of the intermediate shaft 16 of FIG. . Since FIGS. 3 and 4 of the first embodiment are common to the second embodiment, the description of the second embodiment will be described with reference to FIGS. 3 and 4 of the first embodiment.

  As shown in FIG. 7 to FIG. 9 and FIG. 3 to FIG. 4, the vehicle rear side (right side in FIG. 7) of the female intermediate shaft (female shaft) 16B is the vehicle front side of the male intermediate shaft (male shaft) 16A. (The left side in FIG. 7) is externally fitted and connected. The female intermediate shaft 16B is formed in a hollow cylindrical shape, and an axial groove 41 (female shaft side axial groove) 41 having a substantially semicircular cross section at the axis perpendicular to the inner periphery of the inner diameter hole 40 has a telescopic stroke. Six pieces are formed at equal intervals (60-degree intervals) over the entire length.

  The front side of the vehicle body of the male intermediate shaft 16A is formed in a solid cylindrical shape. From the front side of the vehicle body, a large diameter shaft portion 50 having a large diameter and a diameter smaller than that of the large diameter shaft portion 50 are formed. The small-diameter shaft portions 51 are formed in this order.

  A small-diameter cylindrical portion 44 is formed at the vehicle body rear end of the female intermediate shaft 16B, and an inner periphery 421 of a thin cylindrical wiper mounting plate 42 is press-fitted into an outer periphery 441 of the small-diameter cylindrical portion 44. The wiper mounting plate 42 is bent in an L shape toward the axial center of the male intermediate shaft 16A at the vehicle body rear side end surface 442 of the small diameter cylindrical portion 44 to form a bent portion 422.

  A wiper 43 made of rubber or the like is fixed to the bent portion 422. The wiper 43 slides on the outer periphery 511 of the small-diameter shaft portion 51, and dust is generated in the fitting portion between the female intermediate shaft 16B and the male intermediate shaft 16A. Prevents intrusion. The wiper mounting plate 42 is manufactured by pressing a thin steel plate and presses the front end of the vehicle body on the inner periphery 421 of the wiper mounting plate 42 into the outer periphery 441 of the small diameter cylindrical portion 44.

  On the outer periphery of the large diameter shaft portion 50 of the male intermediate shaft 16 </ b> A, three axial grooves (male shaft side axial grooves) 54 having a substantially trapezoidal cross section at the right angle are provided on the front end 501 of the large diameter shaft portion 50. Are formed at equal intervals (120 degree intervals) over substantially the entire axial length of the large-diameter shaft portion 50. The axial groove 54 having a substantially trapezoidal cross section at right angles to the axis is for ball rolling.

  As shown in FIG. 7, the axial length of the ball rolling axial groove 54 is formed as a length L3, which is obtained by adding a length L1 and a length L2. That is, the length L1 is the length in the axial direction necessary for the ball 55 as the rolling element to roll in a telescopic motion during a normal driving operation. The length L2 is an axial length necessary for the ball 55 to roll when the intermediate shaft 16 is contracted beyond the contraction distance during normal driving operation when the steering device is assembled.

  In a space formed by the three axial grooves 54 for ball rolling and the three axial grooves 41 of the female intermediate shaft 16B in the same phase as the axial grooves 54, a plurality of spherical balls as rolling elements are formed. (Five) balls 55 are respectively inserted.

  A disc-shaped washer 58, a disc-shaped spring plate 59, and a disc-shaped washer 60 are provided on the small-diameter shaft portion 57 formed at the front end 501 of the large-diameter portion 50 of the male intermediate shaft 16A from the rear side of the vehicle body. They are fitted in order. The front end of the vehicle body of the small-diameter shaft portion 57 is crimped, and the spring plate 59 applies a biasing force to the vehicle body rear side (right side in FIG. 7) to the vehicle body rear side washer.

  Further, on the outer periphery of the large-diameter shaft portion 50 of the male intermediate shaft 16A, three axial grooves having a substantially semicircular cross-section at a right angle in the middle position between the three axial grooves 54, 54 for ball rolling. (Male shaft side axial groove) 52 is formed to have the same length L3 as the axial length L3 of the axial groove 54 for ball rolling, and is formed at equal intervals (120 degree intervals).

  A solid cylindrical pin as a rotational torque transmitting member is formed in a cylindrical space formed by the three axial grooves 52 of the male intermediate shaft 16A and the three axial grooves 41 of the female intermediate shaft 16B. (Needle rollers) 53A and 53B are inserted. The cylindrical pins 53A and 53B are arranged in series in a cylindrical space formed by the axial groove 52 and the axial groove 41, with the cylindrical pin 53A disposed on the front side of the vehicle body and the cylindrical pin 53B disposed on the rear side of the vehicle body. Has been inserted.

  The columnar pins 53A and 53B are the same parts having the same length in the axial direction, and the length L4 from the vehicle body front end of the columnar pin 53A to the vehicle body rear end of the columnar pin 53B is the axis. The directional groove 52 is formed slightly longer than the axial length L3.

  The outer diameter of the cylindrical pins 53A and 53B is slightly larger than the inner diameter of the cylindrical space formed by the axial groove 52 of the male intermediate shaft 16A and the axial groove 41 of the female intermediate shaft 16B. It has a small diameter.

  The end surface of the washer 58 on the vehicle body rear side is in contact with the vehicle body front end of the cylindrical pin 53A, and has a function as a regulating member that regulates the axial movement of the cylindrical pins 53A and 53B. A wall 521 perpendicular to the axis of the male intermediate shaft 16A is formed at the rear end of the axial groove 52 in the vehicle body, and receives the rear end of the cylindrical pin 53B. In addition, the vehicle body rear end and the vehicle body front end of the cylindrical pins 53A and 53B have a crowning or tapered shape and are reduced in diameter toward the end side.

  A leaf spring (biasing member) 56 as a preload application member is inserted between the three substantially trapezoidal axial grooves 54 and the ball 55. As shown in detail in FIG. 3 (2), the axial groove 54 is composed of a bottom surface 541 wider than the diameter of the ball 55 and side surfaces 542 and 542 extending upward in a V shape from both ends of the bottom surface 541. ing. The bottom surface 541 is formed orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A as viewed in the cross-section perpendicular to the axis in FIG.

  The leaf spring 56 is substantially parallel to the side surfaces 542 and 542 of the axial groove 54, extends upward in a V shape from the bottom surface 541, and a pair of rolling element side contact portions 562 and 562 that respectively contact the ball 55, and the rolling element side It is comprised by the connection part 561 which connects the radial direction inner end of the contact parts 562 and 562. FIG. The connecting portion 561 is in contact with the bottom surface 541 of the axial groove 54 and is spaced a predetermined distance radially inward from the radially inner end of the ball 55.

  In addition, a pair of urging portions 563 and 563 are formed at the upper ends of the rolling element side contact portions 562 and 562, respectively, and are bent outward in a circular arc shape, and downward from the urging portions 563 and 563 toward the bottom surface 541. The groove side surface side contact portions 564 and 564 are formed so as to contact the side surface 542 of the axial groove 54. The urging portions 563 and 563 elastically urge the rolling element side contact portions 562 and 562 and the groove side surface contact portions 564 and 564 in a direction away from each other.

  As shown in FIG. 7, the axial lengths of the rolling element side contact portions 562 and 562, the biasing portions 563 and 563, the groove side surface contact portions 564 and 564, and the connecting portion 561 of the leaf spring 56 are as described above. The axial length 54 of the axial groove 54 is substantially the same as the axial length L1 (the axial length necessary for the ball 55 to roll in a telescopic operation during a normal driving operation).

  The plate spring 56 is inserted between the axial groove 54 and the ball 55 by being elastically deformed with the vehicle body front end 565 matched with the vehicle body front end 501 of the large-diameter shaft portion 50. Accordingly, in the leaf spring 56, the biasing portions 563 and 563 are mainly elastically deformed to absorb the rotational and radial play between the ball 55 and the axial groove 54 and the axial groove 41.

  There are minute gaps between the cylindrical pins 53A, 53B and the axial grooves 41 and 52. When the female intermediate shaft 16B and the male intermediate shaft 16A are relatively displaced by a slight angle in the rotational direction, the cylindrical pins 53A and 53B come into contact with the axial groove 41 and the axial groove 52.

  However, the leaf spring 56 is inserted in a compressed state between the ball 55 and the substantially trapezoidal axial groove 54, and the leaf spring 56 is inserted between the axial groove 54, the ball 55, and the axial groove 41. An urging force (predetermined preload) due to elastic deformation is applied.

  Therefore, there is no play in the rotational direction or radial direction between the female intermediate shaft 16B and the male intermediate shaft 16A. Further, even if there is an eccentricity or inclination between the female intermediate shaft 16B and the male intermediate shaft 16A, it can be absorbed by the elastic force of the leaf spring 56.

  As shown in FIGS. 4 and 7 to 9, the connecting portion 561 is formed with an extension portion 71 extending further from the vehicle body rear end 566 toward the vehicle body rear side. The extension portion 71 has a flat plate shape and is formed orthogonal to a normal line 161 passing through the axis of the male intermediate shaft 16A when viewed in a cross section perpendicular to the axis in FIG. In addition, the extension portion 71 is configured from the front side of the vehicle body in the order of the inclined extension portion 712 and the parallel extension portion 711, and is slightly narrower than the width of the connecting portion 561 and has a constant width W. A length L2 is formed parallel to the axis of the shaft 16A.

  That is, there is a gap δ1 between the bottom surface 541 of the axial groove 54 and the parallel extension portion 711 parallel to the bottom surface 541, the vehicle body front end of the parallel extension portion 711, and the vehicle body rear end of the connecting portion 561 are smooth. It is comprised by the inclination extension part 712 to connect. The inclined extension portion 712 smoothly guides the ball 55 rolling along the rolling element side contact portions 562 and 562 of the leaf spring 56 to the parallel extension portion 711.

  A folded portion 713 that contacts the bottom surface 541 of the axial groove 54 is formed at the vehicle body rear end of the parallel extension portion 711. A wall 543 orthogonal to the axis of the male intermediate shaft 16A is formed at the vehicle body rear end of the axial groove 54, and the vehicle body rear end of the folded portion 713 is in contact with the wall 543. Accordingly, the parallel extending portion 711 is supported in a both-end supported state with both the vehicle body rear end 566 and the folded portion 713 of the connecting portion 561 as fulcrums.

  The parallel extension 711 elastically deforms and contacts the inner end of the ball 55 in the radial direction, and the elastic force of the inclined extension 712 and the parallel extension 711 causes the ball 55 to move with respect to the axial groove 41 of the female shaft 16B. Preload is applied. Since the parallel extension portion 711 is formed in a flat plate shape orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A, it applies only a radial preload and does not apply a rotational preload.

  That is, during normal driving operation, rotational torque acts between the ball 55 and the axial groove 54 and the axial groove 41, but when the telescopic shaft contracts beyond the contraction distance during normal driving operation, No rotational torque acts between the ball 55 and the axial groove 54 or the axial groove 41.

  For this reason, it is sufficient to apply only the radial preload necessary for the ball 55 to roll smoothly and without backlash, so that the shape of the extension 71 may be a simple flat plate. Accordingly, the axial lengths of the complicated shape portions (rolling body side contact portion 562, urging portion 563, groove side surface side contact portion 564, and connecting portion 561) that need to be manufactured with high accuracy can be the same as the conventional length. Therefore, it is easy to manufacture the leaf spring, and it is not necessary to add a plate spring correction process, and it is possible to minimize an increase in the manufacturing cost of the leaf spring.

  When the male intermediate shaft 16A is moved (contracted) in the left direction in FIG. 7 with respect to the female intermediate shaft 16B, the ball 55 rotates clockwise, and the ball 55 rolls along the axial groove 54. Move to the rear (right direction) of the car.

  Further, when the male intermediate shaft 16A is moved to the left in FIG. 7 with respect to the female intermediate shaft 16B and exceeds the contraction distance during normal driving operation, the rolling elements of the leaf spring 56 are sequentially from the ball 55 at the rearmost end of the vehicle body. The side contact portion 562, the urging portion 563, the groove side contact portion 564, and the connecting portion 561 over the vehicle body rear end 566, ride on the inclined extension portion 712, and are guided by the inclined extension portion 712 to reach the parallel extension portion 711. .

  As a result, as shown by a two-dot chain line in FIGS. 7 and 9, the parallel extension portion 711 is elastically deformed and contacts the radially inner end of the ball 55, and the elastic force of the inclined extension portion 712 and the parallel extension portion 711 is obtained. Thus, a preload is applied to the ball 55 in the radially outward direction with respect to the axial groove 41 of the female shaft 16B.

  Since the parallel extension portion 711 is supported in a both-sided manner with both the vehicle body rear end 566 and the turn-up portion 713 of the connecting portion 561 as fulcrums, the parallel extension portion 711 is located between the parallel extension portion 711 and the bottom surface 541 of the axial groove 54. Can be reliably set to the predetermined gap δ1, and a constant gap δ1 can be ensured over the entire length of the parallel extension portion 711 in the axial direction. Therefore, variation in the magnitude of the preload applied to each of the plurality of balls 55 is suppressed, and it becomes easy to apply a preload having a predetermined magnitude.

  Therefore, even when the telescopic shaft is contracted beyond a predetermined contraction distance when the steering device is assembled, a preload having a predetermined size can be applied to the ball 55 with respect to the axial groove 41 of the female shaft 16B. Therefore, a smooth contraction operation without play can be performed.

  Next, after the assembly operation is completed, when the male intermediate shaft 16A is moved in the right direction in FIG. 7 with respect to the female intermediate shaft 16B, the ball 55 rotates counterclockwise, and the ball 55 is moved to the parallel extension 711, While rolling along the axial groove 41, the vehicle moves forward (to the left) in the vehicle body.

  Further, when the male intermediate shaft 16A is moved to the right in FIG. 7 with respect to the female intermediate shaft 16B, the rolling extension side contact portion of the leaf spring 56 is guided to the inclined extension portion 712 in order from the ball 55 at the front end of the vehicle body. 562, the urging portion 563, the groove side surface contact portion 564, and the vehicle body rear end 566 of the connecting portion 561.

  Accordingly, when the assembling work is completed and all of the five balls 55 reach the rolling element side contact portion 562, the urging portion 563, the groove side contact portion 564, and the connecting portion 561 of the leaf spring 56, the normal driving operation is performed. At the time of the expansion / contraction operation, the ball 55 rolls, and the expansion / contraction operation of the intermediate shaft 16 is performed smoothly. Further, the rigidity in the rotational direction and the radial direction between the male intermediate shaft 16A and the female intermediate shaft 16B is ensured, and a good steering feeling can be obtained.

  Next, a third embodiment of the present invention will be described. FIG. 10 is a view corresponding to FIG. 2 showing the expansion / contraction portion of the intermediate shaft according to the third embodiment of the present invention. FIG. 11 is an enlarged cross-sectional view of a portion R in FIG. In the following description, the same structural portion and operation as in the above embodiment will be described without any duplication. Further, the same parts as those in the above embodiment will be described with the same numbers.

  The third embodiment is a modification of the first embodiment. In the first embodiment, the extension portion 71 is supported in a cantilever state with the vehicle body rear end 566 of the connecting portion 561 as a fulcrum, but the third embodiment is an example in which the extension portion 71 is supported in a both-end support state. . That is, FIG. 10 to FIG. 11 show the connecting part of the telescopic shaft of Example 3 of the present invention, and show an example applied to the connecting part of the male intermediate shaft 16A and the female intermediate shaft 16B of the intermediate shaft 16 of FIG. . Since FIGS. 3 to 5 of the first embodiment are common to the third embodiment, the description of the third embodiment will be described using FIGS. 3 to 5 of the first embodiment.

  As shown in FIG. 10 to FIG. 11 and FIG. 3 to FIG. 5, the vehicle body rear side (right side in FIG. 10) of the female intermediate shaft (female shaft) 16B is the vehicle body front side of the male intermediate shaft (male shaft) 16A. (The left side in FIG. 10) is connected by external fitting. The female intermediate shaft 16B is formed in a hollow cylindrical shape, and an axial groove 41 (female shaft side axial groove) 41 having a substantially semicircular cross section at the axis perpendicular to the inner periphery of the inner diameter hole 40 has a telescopic stroke. Six pieces are formed at equal intervals (60-degree intervals) over the entire length.

  The front side of the vehicle body of the male intermediate shaft 16A is formed in a solid cylindrical shape. From the front side of the vehicle body, a large diameter shaft portion 50 having a large diameter and a diameter smaller than that of the large diameter shaft portion 50 are formed. The small-diameter shaft portions 51 are formed in this order.

  A small-diameter cylindrical portion 44 is formed at the vehicle body rear end of the female intermediate shaft 16B, and an inner periphery 421 of a thin cylindrical wiper mounting plate 42 is press-fitted into an outer periphery 441 of the small-diameter cylindrical portion 44. The wiper mounting plate 42 is bent in an L shape toward the axial center of the male intermediate shaft 16A at the vehicle body rear side end surface 442 of the small diameter cylindrical portion 44 to form a bent portion 422.

  A wiper 43 made of rubber or the like is fixed to the bent portion 422. The wiper 43 slides on the outer periphery 511 of the small-diameter shaft portion 51, and dust is generated in the fitting portion between the female intermediate shaft 16B and the male intermediate shaft 16A. Prevents intrusion. The wiper mounting plate 42 is manufactured by pressing a thin steel plate and presses the front end of the vehicle body on the inner periphery 421 of the wiper mounting plate 42 into the outer periphery 441 of the small diameter cylindrical portion 44.

  On the outer periphery of the large diameter shaft portion 50 of the male intermediate shaft 16 </ b> A, three axial grooves (male shaft side axial grooves) 54 having a substantially trapezoidal cross section at the right angle are provided on the front end 501 of the large diameter shaft portion 50. Are formed at equal intervals (120 degree intervals) over substantially the entire axial length of the large-diameter shaft portion 50. The axial groove 54 having a substantially trapezoidal cross section at right angles to the axis is for ball rolling.

  As shown in FIG. 10, the axial length of the axial groove 54 for rolling the ball is formed as a length L3 obtained by adding a length L1 and a length L2. That is, the length L1 is the length in the axial direction necessary for the ball 55 as the rolling element to roll in a telescopic motion during a normal driving operation. The length L2 is an axial length necessary for the ball 55 to roll when the intermediate shaft 16 is contracted beyond the contraction distance during normal driving operation when the steering device is assembled.

  In a space formed by the three axial grooves 54 for rolling the ball and the three axial grooves 41 of the female intermediate shaft 16B in the same phase as the axial groove 54, a plurality of spherical ( 5 balls 55 are inserted respectively.

  A disc-shaped washer 58, a disc-shaped spring plate 59, and a disc-shaped washer 60 are provided on the small-diameter shaft portion 57 formed at the front end 501 of the large-diameter portion 50 of the male intermediate shaft 16A from the rear side of the vehicle body. They are fitted in order. The front end of the vehicle body of the small-diameter shaft portion 57 is crimped, and a spring plate 59 applies a biasing force toward the vehicle rear side (right side in FIG. 10) to the washer 58 on the vehicle rear side.

  Further, on the outer periphery of the large-diameter shaft portion 50 of the male intermediate shaft 16A, three axial grooves having a substantially semicircular cross-section at a right angle in the middle position between the three axial grooves 54, 54 for ball rolling. (Male shaft side axial groove) 52 is formed to have the same length L3 as the axial length L3 of the axial groove 54 for ball rolling, and is formed at equal intervals (120 degree intervals).

  A solid cylindrical pin as a rotational torque transmitting member is formed in a cylindrical space formed by the three axial grooves 52 of the male intermediate shaft 16A and the three axial grooves 41 of the female intermediate shaft 16B. (Needle rollers) 53A and 53B are inserted. The cylindrical pins 53A and 53B are arranged in series in a cylindrical space formed by the axial groove 52 and the axial groove 41, with the cylindrical pin 53A disposed on the front side of the vehicle body and the cylindrical pin 53B disposed on the rear side of the vehicle body. Has been inserted.

  The columnar pins 53A and 53B are the same parts having the same length in the axial direction, and the length L4 from the vehicle body front end of the columnar pin 53A to the vehicle body rear end of the columnar pin 53B is the axis. The directional groove 52 is formed slightly longer than the axial length L3.

  The outer diameter of the cylindrical pins 53A and 53B is slightly larger than the inner diameter of the cylindrical space formed by the axial groove 52 of the male intermediate shaft 16A and the axial groove 41 of the female intermediate shaft 16B. It has a small diameter.

  The end surface of the washer 58 on the vehicle body rear side is in contact with the vehicle body front end of the cylindrical pin 53A, and has a function as a regulating member that regulates the axial movement of the cylindrical pins 53A and 53B. A wall 521 perpendicular to the axis of the male intermediate shaft 16A is formed at the rear end of the axial groove 52 in the vehicle body, and receives the rear end of the cylindrical pin 53B. In addition, the vehicle body rear end and the vehicle body front end of the cylindrical pins 53A and 53B have a crowning or tapered shape and are reduced in diameter toward the end side.

  A leaf spring (biasing member) 56 as a preload application member is inserted between the three substantially trapezoidal axial grooves 54 and the ball 55. As shown in detail in FIG. 3 (2), the axial groove 54 is composed of a bottom surface 541 wider than the diameter of the ball 55 and side surfaces 542 and 542 extending upward in a V shape from both ends of the bottom surface 541. ing. The bottom surface 541 is formed orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A as viewed in the cross-section perpendicular to the axis in FIG.

  The leaf spring 56 is substantially parallel to the side surfaces 542 and 542 of the axial groove 54, extends upward in a V shape from the bottom surface 541, and a pair of rolling element side contact portions 562 and 562 that respectively contact the ball 55, and the rolling element side It is comprised by the connection part 561 which connects the radial direction inner end of the contact parts 562 and 562. FIG. The connecting portion 561 is in contact with the bottom surface 541 of the axial groove 54 and is spaced a predetermined distance radially inward from the radially inner end of the ball 55.

  Further, a pair of urging portions 563 and 563 are formed at the upper ends of the rolling element side contact portions 562 and 562, respectively, which are bent outward in a circular arc shape, and downward from the urging portions 563 and 563 toward the bottom surface 541. The groove side surface side contact portions 564 and 564 are formed so as to contact the side surface 542 of the axial groove 54. The urging portions 563 and 563 elastically urge the rolling element side contact portions 562 and 562 and the groove side surface contact portions 564 and 564 in a direction away from each other.

  As shown in FIG. 10, the axial lengths of the rolling element side contact portions 562 and 562, the biasing portions 563 and 563, the groove side surface contact portions 564 and 564, and the connecting portion 561 of the leaf spring 56 are described above. The axial length 54 of the axial groove 54 is substantially the same as the axial length L1 (the axial length necessary for the ball 55 to roll in a telescopic operation during a normal driving operation).

  The plate spring 56 is inserted between the axial groove 54 and the ball 55 by being elastically deformed with the vehicle body front end 565 matched with the vehicle body front end 501 of the large-diameter shaft portion 50. Accordingly, in the leaf spring 56, the biasing portions 563 and 563 are mainly elastically deformed to absorb the rotational and radial play between the ball 55 and the axial groove 54 and the axial groove 41.

  There are minute gaps between the cylindrical pins 53A, 53B and the axial grooves 41 and 52. When the female intermediate shaft 16B and the male intermediate shaft 16A are relatively displaced by a slight angle in the rotational direction, the cylindrical pins 53A and 53B come into contact with the axial groove 41 and the axial groove 52.

  However, the leaf spring 56 is inserted in a compressed state between the ball 55 and the substantially trapezoidal axial groove 54, and the leaf spring 56 is inserted between the axial groove 54, the ball 55, and the axial groove 41. An urging force (predetermined preload) due to elastic deformation is applied.

  Therefore, there is no play in the rotational direction or radial direction between the female intermediate shaft 16B and the male intermediate shaft 16A. Further, even if there is an eccentricity or inclination between the female intermediate shaft 16B and the male intermediate shaft 16A, it can be absorbed by the elastic force of the leaf spring 56.

  As shown in FIGS. 4 and 10 to 11, the connecting portion 561 is formed with an extension portion 71 that extends further from the vehicle body rear end 566 toward the vehicle body rear side. The extension portion 71 has a flat plate shape and is formed orthogonal to a normal line 161 passing through the axis of the male intermediate shaft 16A when viewed in a cross section perpendicular to the axis in FIG. In addition, the extension portion 71 is configured from the front side of the vehicle body in the order of the inclined extension portion 712 and the parallel extension portion 711, and is slightly narrower than the width of the connecting portion 561 and has a constant width W. A length L2 is formed parallel to the axis of the shaft 16A.

  That is, there is a gap δ1 between the bottom surface 541 of the axial groove 54 and the parallel extension portion 711 parallel to the bottom surface 541, the vehicle body front end of the parallel extension portion 711, and the vehicle body rear end of the connecting portion 561 are smooth. It is comprised by the inclination extension part 712 to connect. The inclined extension portion 712 smoothly guides the ball 55 rolling along the rolling element side contact portions 562 and 562 of the leaf spring 56 to the parallel extension portion 711.

  A protruding portion 544 that protrudes outward in the radial direction is formed at the vehicle body rear end of the bottom surface 541 of the axial groove 54. The protruding portion 544 protrudes radially outward from the bottom surface 541 by the same dimension as the gap δ1 between the parallel extending portion 711 and the bottom surface 541 of the axial groove 54 and contacts the rear end of the parallel extending portion 711 in the vehicle body. Yes. A wall 543 orthogonal to the axis of the male intermediate shaft 16A is formed at the vehicle body rear end of the axial groove 54, and the vehicle body rear end of the parallel extension 711 is in contact with the wall 543. Accordingly, the parallel extension portion 711 is supported in a both-end supported state with both contact points between the vehicle body rear end 566 of the connecting portion 561 and the protruding portion 544 as fulcrums.

  The parallel extension 711 elastically deforms and contacts the inner end of the ball 55 in the radial direction, and the elastic force of the inclined extension 712 and the parallel extension 711 causes the ball 55 to move with respect to the axial groove 41 of the female shaft 16B. Preload is applied. Since the parallel extension portion 711 is formed in a flat plate shape orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A, it applies only a radial preload and does not apply a rotational preload.

  That is, during normal driving operation, rotational torque acts between the ball 55 and the axial groove 54 and the axial groove 41, but when the telescopic shaft contracts beyond the contraction distance during normal driving operation, No rotational torque acts between the ball 55 and the axial groove 54 or the axial groove 41.

  For this reason, it is sufficient to apply only the radial preload necessary for the ball 55 to roll smoothly and without backlash, so that the shape of the extension 71 may be a simple flat plate. Accordingly, the axial lengths of the complicated shape portions (rolling body side contact portion 562, urging portion 563, groove side surface side contact portion 564, and connecting portion 561) that need to be manufactured with high accuracy can be the same as the conventional length. Therefore, it is easy to manufacture the leaf spring, and it is not necessary to add a plate spring correction process, and it is possible to minimize an increase in the manufacturing cost of the leaf spring.

  When the male intermediate shaft 16A is moved (contracted) to the left in FIG. 10 with respect to the female intermediate shaft 16B, the ball 55 rotates clockwise, and the ball 55 rolls along the axial groove 54. Move to the rear (right direction) of the car.

  Further, when the male intermediate shaft 16A is moved to the left in FIG. 10 with respect to the female intermediate shaft 16B and exceeds the contraction distance during normal driving operation, the rolling elements of the leaf spring 56 are sequentially from the ball 55 at the rearmost end of the vehicle body. The side contact portion 562, the biasing portion 563, the groove side contact portion 564, and the connecting portion 561 over the rear end 566 of the vehicle body, ride on the inclined extension portion 712, and are guided by the inclined extension portion 712 to reach the parallel extension portion 711. .

  As a result, as shown by a two-dot chain line in FIGS. 10 and 11, the parallel extension 711 is elastically deformed and brought into contact with the radially inner end of the ball 55, and the elastic force of the inclined extension 712 and the parallel extension 711. Thus, a preload is applied to the ball 55 in the radially outward direction with respect to the axial groove 41 of the female shaft 16B.

  Since the parallel extension portion 711 is supported in a supported state with both contact points between the vehicle body rear end 566 of the connecting portion 561 and the protruding portion 544 as fulcrums, the parallel extension portion 711 and the bottom surface of the axial groove 54 are supported. It is easy to reliably set the gap with respect to 541 to the predetermined gap δ1, and a constant gap δ1 can be ensured over the entire length of the parallel extension portion 711 in the axial direction. Therefore, variation in the magnitude of the preload applied to each of the plurality of balls 55 is suppressed, and it becomes easy to apply a preload having a predetermined magnitude.

  Therefore, even when the telescopic shaft is contracted beyond a predetermined contraction distance when the steering device is assembled, a preload having a predetermined size can be applied to the ball 55 with respect to the axial groove 41 of the female shaft 16B. Therefore, a smooth contraction operation without play can be performed.

  Next, after the assembly operation is completed, when the male intermediate shaft 16A is moved in the right direction in FIG. 10 with respect to the female intermediate shaft 16B, the ball 55 is rotated counterclockwise, and the ball 55 is While rolling along the axial groove 41, the vehicle moves forward (to the left) in the vehicle body.

  Further, when the male intermediate shaft 16A is moved to the right in FIG. 10 with respect to the female intermediate shaft 16B, the rolling extension side contact portion of the leaf spring 56 is guided to the inclined extension portion 712 in order from the ball 55 at the front end of the vehicle body. 562, the urging portion 563, the groove side surface contact portion 564, and the vehicle body rear end 566 of the connecting portion 561.

  Accordingly, when the assembling work is completed and all of the five balls 55 reach the rolling element side contact portion 562, the urging portion 563, the groove side contact portion 564, and the connecting portion 561 of the leaf spring 56, the normal driving operation is performed. At the time of the expansion / contraction operation, the ball 55 rolls, and the expansion / contraction operation of the intermediate shaft 16 is performed smoothly. Further, the rigidity in the rotational direction and the radial direction between the male intermediate shaft 16A and the female intermediate shaft 16B is ensured, and a good steering feeling can be obtained.

  Next, a fourth embodiment of the present invention will be described. FIG. 12 is a view corresponding to FIG. 2 showing the expansion / contraction portion of the intermediate shaft according to the fourth embodiment of the present invention. FIG. 13 is a perspective view showing a leaf spring according to the fourth embodiment of the present invention. 14 (1) is an enlarged cross-sectional view of the S portion of FIG. 12, FIG. 14 (2) is a CC enlarged cross-sectional view of FIG. 14 (1), and corresponds to FIG. 4 (2). In the following description, the same structural portion and operation as in the above embodiment will be described without any duplication. Further, the same parts as those in the above embodiment will be described with the same numbers.

  The fourth embodiment is a modification of the first embodiment. In the first embodiment, an inclined extension portion 712 that smoothly connects the vehicle body front end of the parallel extension portion 711 and the vehicle body rear end of the connecting portion 561 is formed, and along the rolling element side contact portions 562 and 562 of the leaf spring 56. The rolling ball 55 is smoothly guided to the parallel extension 711.

  On the other hand, the fourth embodiment is an example in which the shape of the inclined extension portion of the first embodiment is changed and formed into a mountain shape having a vertex protruding radially outward from the radial outer end of the parallel extension portion 711. That is, FIGS. 12 to 14 show the connecting portion of the telescopic shaft according to the fourth embodiment of the present invention, and show an example applied to the connecting portion between the male intermediate shaft 16A and the female intermediate shaft 16B of the intermediate shaft 16 of FIG. . Further, FIG. 3 of the first embodiment is common to the fourth embodiment, and therefore, in the description of the fourth embodiment, the description will be made by using FIG. 3 of the first embodiment.

  As shown in FIGS. 12 to 14 and FIG. 3, the rear side of the vehicle body of the female intermediate shaft (female shaft) 16B (the right side of FIG. 12) is the front side of the vehicle body of the male intermediate shaft (male shaft) 16A (FIG. 12). To the left side). The female intermediate shaft 16B is formed in a hollow cylindrical shape, and an axial groove 41 (female shaft side axial groove) 41 having a substantially semicircular cross section at the axis perpendicular to the inner periphery of the inner diameter hole 40 has a telescopic stroke. Six pieces are formed at equal intervals (60-degree intervals) over the entire length.

  The front side of the vehicle body of the male intermediate shaft 16A is formed in a solid cylindrical shape. From the front side of the vehicle body, a large diameter shaft portion 50 having a large diameter and a diameter smaller than that of the large diameter shaft portion 50 are formed. The small-diameter shaft portions 51 are formed in this order.

  A small-diameter cylindrical portion 44 is formed at the vehicle body rear end of the female intermediate shaft 16B, and an inner periphery 421 of a thin cylindrical wiper mounting plate 42 is press-fitted into an outer periphery 441 of the small-diameter cylindrical portion 44. The wiper mounting plate 42 is bent in an L shape toward the axial center of the male intermediate shaft 16A at the vehicle body rear side end surface 442 of the small diameter cylindrical portion 44 to form a bent portion 422.

  A wiper 43 made of rubber or the like is fixed to the bent portion 422. The wiper 43 slides on the outer periphery 511 of the small-diameter shaft portion 51, and dust is generated in the fitting portion between the female intermediate shaft 16B and the male intermediate shaft 16A. Prevents intrusion. The wiper mounting plate 42 is manufactured by pressing a thin steel plate and presses the front end of the vehicle body on the inner periphery 421 of the wiper mounting plate 42 into the outer periphery 441 of the small diameter cylindrical portion 44.

  On the outer periphery of the large diameter shaft portion 50 of the male intermediate shaft 16 </ b> A, three axial grooves (male shaft side axial grooves) 54 having a substantially trapezoidal cross section at the right angle are provided on the front end 501 of the large diameter shaft portion 50. Are formed at equal intervals (120 degree intervals) over substantially the entire axial length of the large-diameter shaft portion 50. The axial groove 54 having a substantially trapezoidal cross section at right angles to the axis is for ball rolling.

  As shown in FIG. 12, the axial length of the ball rolling axial groove 54 is formed as a length L3, which is obtained by adding a length L1 and a length L2. That is, the length L1 is the length in the axial direction necessary for the ball 55 as the rolling element to roll in a telescopic motion during a normal driving operation. The length L2 is an axial length necessary for the ball 55 to roll when the intermediate shaft 16 is contracted beyond the contraction distance during normal driving operation when the steering device is assembled.

  In a space formed by the three axial grooves 54 for rolling the ball and the three axial grooves 41 of the female intermediate shaft 16B in the same phase as the axial groove 54, a plurality of spherical ( 5 balls 55 are inserted respectively.

  A disc-shaped washer 58, a disc-shaped spring plate 59, and a disc-shaped washer 60 are provided on the small-diameter shaft portion 57 formed at the front end 501 of the large-diameter portion 50 of the male intermediate shaft 16A from the rear side of the vehicle body. They are fitted in order. The front end of the vehicle body of the small-diameter shaft portion 57 is crimped, and a spring plate 59 applies a biasing force toward the vehicle rear side (right side in FIG. 12) to the washer 58 on the vehicle rear side.

  Further, on the outer periphery of the large-diameter shaft portion 50 of the male intermediate shaft 16A, three axial grooves having a substantially semicircular cross-section at a right angle in the middle position between the three axial grooves 54, 54 for ball rolling. (Male shaft side axial groove) 52 is formed to have the same length L3 as the axial length L3 of the axial groove 54 for ball rolling, and is formed at equal intervals (120 degree intervals).

  A solid cylindrical pin as a rotational torque transmitting member is formed in a cylindrical space formed by the three axial grooves 52 of the male intermediate shaft 16A and the three axial grooves 41 of the female intermediate shaft 16B. (Needle rollers) 53A and 53B are inserted. The cylindrical pins 53A and 53B are arranged in series in a cylindrical space formed by the axial groove 52 and the axial groove 41, with the cylindrical pin 53A disposed on the front side of the vehicle body and the cylindrical pin 53B disposed on the rear side of the vehicle body. Has been inserted.

  The columnar pins 53A and 53B are the same parts having the same length in the axial direction, and the length L4 from the vehicle body front end of the columnar pin 53A to the vehicle body rear end of the columnar pin 53B is the axis. The directional groove 52 is formed slightly longer than the axial length L3.

  The outer diameter of the cylindrical pins 53A and 53B is slightly larger than the inner diameter of the cylindrical space formed by the axial groove 52 of the male intermediate shaft 16A and the axial groove 41 of the female intermediate shaft 16B. It has a small diameter.

  The end surface of the washer 58 on the vehicle body rear side is in contact with the vehicle body front end of the cylindrical pin 53A, and has a function as a regulating member that regulates the axial movement of the cylindrical pins 53A and 53B. A wall 521 perpendicular to the axis of the male intermediate shaft 16A is formed at the rear end of the axial groove 52 in the vehicle body, and receives the rear end of the cylindrical pin 53B. In addition, the vehicle body rear end and the vehicle body front end of the cylindrical pins 53A and 53B have a crowning or tapered shape and are reduced in diameter toward the end side.

  A leaf spring (biasing member) 56 as a preload application member is inserted between the three substantially trapezoidal axial grooves 54 and the ball 55. As shown in detail in FIG. 3 (2), the axial groove 54 is composed of a bottom surface 541 wider than the diameter of the ball 55 and side surfaces 542 and 542 extending upward in a V shape from both ends of the bottom surface 541. ing. The bottom surface 541 is formed orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A as viewed in the cross-section perpendicular to the axis in FIG.

  The leaf spring 56 is substantially parallel to the side surfaces 542 and 542 of the axial groove 54, extends upward in a V shape from the bottom surface 541, and a pair of rolling element side contact portions 562 and 562 that respectively contact the ball 55, and the rolling element side It is comprised by the connection part 561 which connects the radial direction inner end of the contact parts 562 and 562. FIG. The connecting portion 561 is in contact with the bottom surface 541 of the axial groove 54 and is spaced a predetermined distance radially inward from the radially inner end of the ball 55.

  Further, a pair of urging portions 563 and 563 are formed at the upper ends of the rolling element side contact portions 562 and 562, respectively, which are bent outward in a circular arc shape, and downward from the urging portions 563 and 563 toward the bottom surface 541. The groove side surface side contact portions 564 and 564 are formed so as to contact the side surface 542 of the axial groove 54. The urging portions 563 and 563 elastically urge the rolling element side contact portions 562 and 562 and the groove side surface contact portions 564 and 564 in a direction away from each other.

  As shown in FIG. 12, the axial lengths of the rolling element side contact portions 562 and 562, the biasing portions 563 and 563, the groove side surface side contact portions 564 and 564, and the connecting portion 561 of the leaf spring 56 are as described above. The axial length 54 of the axial groove 54 is substantially the same as the axial length L1 (the axial length necessary for the ball 55 to roll in a telescopic operation during a normal driving operation).

  The plate spring 56 is inserted between the axial groove 54 and the ball 55 by being elastically deformed with the vehicle body front end 565 matched with the vehicle body front end 501 of the large-diameter shaft portion 50. Accordingly, in the leaf spring 56, the biasing portions 563 and 563 are mainly elastically deformed to absorb the rotational and radial play between the ball 55 and the axial groove 54 and the axial groove 41.

  There are minute gaps between the cylindrical pins 53A, 53B and the axial grooves 41 and 52. When the female intermediate shaft 16B and the male intermediate shaft 16A are relatively displaced by a slight angle in the rotational direction, the cylindrical pins 53A and 53B come into contact with the axial groove 41 and the axial groove 52.

  However, the leaf spring 56 is inserted in a compressed state between the ball 55 and the substantially trapezoidal axial groove 54, and the leaf spring 56 is inserted between the axial groove 54, the ball 55, and the axial groove 41. An urging force (predetermined preload) due to elastic deformation is applied.

  Therefore, there is no play in the rotational direction or radial direction between the female intermediate shaft 16B and the male intermediate shaft 16A. Further, even if there is an eccentricity or inclination between the female intermediate shaft 16B and the male intermediate shaft 16A, it can be absorbed by the elastic force of the leaf spring 56.

  As shown in FIGS. 12 to 14, the connecting portion 561 is formed with an extension portion 71 that extends further from the vehicle body rear end 566 toward the vehicle body rear side. The extension 71 has a flat plate shape and is formed perpendicular to a normal line 161 passing through the axis of the male intermediate shaft 16A when viewed in the cross section perpendicular to the axis in FIG. Further, the extension portion 71 is configured from the front side of the vehicle body in the order of the inclined extension portion 714 and the parallel extension portion 711. The extension portion 71 is slightly narrower than the width of the connecting portion 561 and has a constant width W. A length L2 is formed parallel to the axis of the shaft 16A.

  That is, there is a gap δ1 between the bottom surface 541 of the axial groove 54 and the parallel extension portion 711 parallel to the bottom surface 541, the vehicle body front end of the parallel extension portion 711, and the vehicle body rear end of the connecting portion 561 are smooth. It is comprised by the inclination extension part 714 to connect. The inclined extension portion 714 is formed in a mountain shape having a vertex 714A that protrudes by a height δ2 radially outward from the radially outer end of the parallel extension portion 711, and extends along the rolling element side contact portions 562 and 562 of the leaf spring 56. Thus, the rolling ball 55 is smoothly guided to the parallel extension 711.

  A wall 543 orthogonal to the axis of the male intermediate shaft 16 </ b> A is formed at the vehicle body rear end of the axial groove 54, and the vehicle body rear end of the parallel extension 711 is in contact with the wall 543. Accordingly, the parallel extension 711 is supported in a cantilevered manner with the vehicle body rear end 566 of the connecting portion 561 as a fulcrum.

  The parallel extension 711 elastically deforms and contacts the inner end of the ball 55 in the radial direction, and the elastic force of the inclined extension 714 and the parallel extension 711 causes the ball 55 to move with respect to the axial groove 41 of the female shaft 16B. Preload is applied. Since the parallel extension portion 711 is formed in a flat plate shape orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A, it applies only a radial preload and does not apply a rotational preload.

  That is, during normal driving operation, rotational torque acts between the ball 55 and the axial groove 54 and the axial groove 41, but when the telescopic shaft contracts beyond the contraction distance during normal driving operation, No rotational torque acts between the ball 55 and the axial groove 54 or the axial groove 41.

  For this reason, it is sufficient to apply only the radial preload necessary for the ball 55 to roll smoothly and without backlash, so that the shape of the extension 71 may be a simple flat plate. Accordingly, the axial lengths of the complicated shape portions (rolling body side contact portion 562, urging portion 563, groove side surface side contact portion 564, and connecting portion 561) that need to be manufactured with high accuracy can be the same as the conventional length. Therefore, it is easy to manufacture the leaf spring, and it is not necessary to add a plate spring correction process, and it is possible to minimize an increase in the manufacturing cost of the leaf spring.

  When the male intermediate shaft 16A is moved (contracted) to the left in FIG. 12 with respect to the female intermediate shaft 16B, the ball 55 rotates clockwise, and the ball 55 rolls along the axial groove 54. Move to the rear (right direction) of the car.

  Further, the male intermediate shaft 16A is moved to the left in FIG. 12 with respect to the female intermediate shaft 16B, and when the contraction distance during normal driving operation is exceeded, the rolling elements of the leaf spring 56 are sequentially from the ball 55 at the rearmost end of the vehicle body. After the side contact portion 562, the biasing portion 563, the groove side contact portion 564, and the connecting portion 561 over the vehicle body rear end 566, ride on the inclined extension portion 714, and are guided by the inclined extension portion 714 to get over the vertex 714A. The parallel extension 711 is reached.

  As a result, as shown by a two-dot chain line in FIGS. 12 and 14, the parallel extension portion 711 is elastically deformed and contacts the radially inner end of the ball 55, and the elastic force of the inclined extension portion 714 and the parallel extension portion 711 is obtained. Thus, a preload is applied to the ball 55 in the radially outward direction with respect to the axial groove 41 of the female shaft 16B.

  Therefore, even when the telescopic shaft is contracted beyond a predetermined contraction distance when the steering device is assembled, a preload having a predetermined size can be applied to the ball 55 with respect to the axial groove 41 of the female shaft 16B. Therefore, a smooth contraction operation without play can be performed.

  Next, after the assembly operation is completed, when the male intermediate shaft 16A is moved in the right direction in FIG. 12 with respect to the female intermediate shaft 16B, the ball 55 rotates counterclockwise, and the ball 55 is moved to the parallel extension 711, While rolling along the axial groove 41, the vehicle moves forward (to the left) in the vehicle body.

  Further, when the male intermediate shaft 16A is moved in the right direction of FIG. 12 with respect to the female intermediate shaft 16B, the leaf spring is guided by the inclined extension 714 in order from the ball 55 at the front end of the vehicle body and over the vertex 714A. The rolling body side contact portion 562, the urging portion 563, the groove side surface side contact portion 564, and the vehicle body rear end 566 of the connecting portion 561 are reached.

  Accordingly, when the assembling work is completed and all of the five balls 55 reach the rolling element side contact portion 562, the urging portion 563, the groove side contact portion 564, and the connecting portion 561 of the leaf spring 56, the normal driving operation is performed. At the time of the expansion / contraction operation, the ball 55 rolls, and the expansion / contraction operation of the intermediate shaft 16 is performed smoothly. Further, the rigidity in the rotational direction and the radial direction between the male intermediate shaft 16A and the female intermediate shaft 16B is ensured, and a good steering feeling can be obtained.

  In the fourth embodiment, with the magnitude of the operator's force during the assembly work, the ball 55 passes over the apex 714A of the inclined extension 714 and passes between the vehicle body rear end 566 and the parallel extension 711 side of the connecting part 561. The protrusion height δ2 of the vertex 714A to the outside in the radial direction is set so that it can move.

  Therefore, when the assembly operation of the steering device to the vehicle body 18 is finished and the vehicle 55 runs on the road, the ball 55 moves over the apex 714A of the inclined extension 714 and moves to the parallel extension 711 side. Since it can be prevented, the rigidity in the rotational direction and the radial direction is always ensured, and a good steering feeling is maintained.

  When shipping the completed steering device alone to the vehicle body assembly factory, the male intermediate shaft 16A is most contracted with respect to the female intermediate shaft 16B beyond the contraction distance during normal driving operation, so that it can be transported. Often the space of the is made small. Even in such a case, it is possible to prevent the ball 55 from moving over the apex 714A of the inclined extension portion 714 and moving toward the vehicle body rear end 566 side due to vibration during transportation.

  Next, a fifth embodiment of the present invention will be described. FIG. 15 is a view corresponding to FIG. 2 showing the expansion / contraction portion of the intermediate shaft according to the fifth embodiment of the present invention. FIG. 16 is a perspective view showing a leaf spring according to the fifth embodiment of the present invention. FIG. 17 is an enlarged sectional view of a T portion in FIG. In the following description, the same structural portion and operation as in the above embodiment will be described without any duplication. Further, the same parts as those in the above embodiment will be described with the same numbers.

  Example 5 is a modification of Example 1, and is an example in which Example 2 and Example 4 are combined. That is, FIGS. 15 to 17 show the connecting portion of the telescopic shaft of the fifth embodiment of the present invention, and show an example applied to the connecting portion between the male intermediate shaft 16A and the female intermediate shaft 16B of the intermediate shaft 16 of FIG. . Moreover, since FIG. 3 of Example 1 and FIG. 14 (2) of Example 4 are common with Example 5, in description of Example 5, FIG. 3 of Example 1 and FIG. ).

  As shown in FIGS. 15 to 17 and FIGS. 3 and 14 (2), the rear side of the vehicle body (right side in FIG. 15) of the female intermediate shaft (female shaft) 16B is the male intermediate shaft (male shaft) 16A. It is externally fitted and connected to the front side of the vehicle body (left side in FIG. 15). The female intermediate shaft 16B is formed in a hollow cylindrical shape, and an axial groove 41 (female shaft side axial groove) 41 having a substantially semicircular cross section at the axis perpendicular to the inner periphery of the inner diameter hole 40 has a telescopic stroke. Six pieces are formed at equal intervals (60-degree intervals) over the entire length.

  The front side of the vehicle body of the male intermediate shaft 16A is formed in a solid cylindrical shape. From the front side of the vehicle body, a large diameter shaft portion 50 having a large diameter and a diameter smaller than that of the large diameter shaft portion 50 are formed. The small-diameter shaft portions 51 are formed in this order.

  A small-diameter cylindrical portion 44 is formed at the vehicle body rear end of the female intermediate shaft 16B, and an inner periphery 421 of a thin cylindrical wiper mounting plate 42 is press-fitted into an outer periphery 441 of the small-diameter cylindrical portion 44. The wiper mounting plate 42 is bent in an L shape toward the axial center of the male intermediate shaft 16A at the vehicle body rear side end surface 442 of the small diameter cylindrical portion 44 to form a bent portion 422.

  A wiper 43 made of rubber or the like is fixed to the bent portion 422. The wiper 43 slides on the outer periphery 511 of the small-diameter shaft portion 51, and dust is generated in the fitting portion between the female intermediate shaft 16B and the male intermediate shaft 16A. Prevents intrusion. The wiper mounting plate 42 is manufactured by pressing a thin steel plate and presses the front end of the vehicle body on the inner periphery 421 of the wiper mounting plate 42 into the outer periphery 441 of the small diameter cylindrical portion 44.

  On the outer periphery of the large diameter shaft portion 50 of the male intermediate shaft 16 </ b> A, three axial grooves (male shaft side axial grooves) 54 having a substantially trapezoidal cross section at the right angle are provided on the front end 501 of the large diameter shaft portion 50. Are formed at equal intervals (120 degree intervals) over substantially the entire axial length of the large-diameter shaft portion 50. The axial groove 54 having a substantially trapezoidal cross section at right angles to the axis is for ball rolling.

  As shown in FIG. 15, the axial length of the ball rolling axial groove 54 is formed to be a length L3 that is the sum of the length L1 and the length L2. That is, the length L1 is the length in the axial direction necessary for the ball 55 as the rolling element to roll in a telescopic motion during a normal driving operation. The length L2 is an axial length necessary for the ball 55 to roll when the intermediate shaft 16 is contracted beyond the contraction distance during normal driving operation when the steering device is assembled.

  In a space formed by the three axial grooves 54 for rolling the ball and the three axial grooves 41 of the female intermediate shaft 16B in the same phase as the axial groove 54, a plurality of spherical ( 5 balls 55 are inserted respectively.

  A disc-shaped washer 58, a disc-shaped spring plate 59, and a disc-shaped washer 60 are provided on the small-diameter shaft portion 57 formed at the front end 501 of the large-diameter portion 50 of the male intermediate shaft 16A from the rear side of the vehicle body. They are fitted in order. The front end of the vehicle body of the small-diameter shaft portion 57 is crimped, and a spring plate 59 applies a biasing force toward the vehicle rear side (right side in FIG. 15) to the washer 58 on the vehicle rear side.

  Further, on the outer periphery of the large-diameter shaft portion 50 of the male intermediate shaft 16A, three axial grooves having a substantially semicircular cross-section at a right angle in the middle position between the three axial grooves 54, 54 for ball rolling. (Male shaft side axial groove) 52 is formed to have the same length L3 as the axial length L3 of the axial groove 54 for ball rolling, and is formed at equal intervals (120 degree intervals).

  A solid cylindrical pin as a rotational torque transmitting member is formed in a cylindrical space formed by the three axial grooves 52 of the male intermediate shaft 16A and the three axial grooves 41 of the female intermediate shaft 16B. (Needle rollers) 53A and 53B are inserted. The cylindrical pins 53A and 53B are arranged in series in a cylindrical space formed by the axial groove 52 and the axial groove 41, with the cylindrical pin 53A disposed on the front side of the vehicle body and the cylindrical pin 53B disposed on the rear side of the vehicle body. Has been inserted.

  The columnar pins 53A and 53B are the same parts having the same length in the axial direction, and the length L4 from the vehicle body front end of the columnar pin 53A to the vehicle body rear end of the columnar pin 53B is the axis. The directional groove 52 is formed slightly longer than the axial length L3.

  The outer diameter of the cylindrical pins 53A and 53B is slightly larger than the inner diameter of the cylindrical space formed by the axial groove 52 of the male intermediate shaft 16A and the axial groove 41 of the female intermediate shaft 16B. It has a small diameter.

  The end surface of the washer 58 on the vehicle body rear side is in contact with the vehicle body front end of the cylindrical pin 53A, and has a function as a regulating member that regulates the axial movement of the cylindrical pins 53A and 53B. A wall 521 perpendicular to the axis of the male intermediate shaft 16A is formed at the rear end of the axial groove 52 in the vehicle body, and receives the rear end of the cylindrical pin 53B. In addition, the vehicle body rear end and the vehicle body front end of the cylindrical pins 53A and 53B have a crowning or tapered shape and are reduced in diameter toward the end side.

  A leaf spring (biasing member) 56 as a preload application member is inserted between the three substantially trapezoidal axial grooves 54 and the ball 55. As shown in detail in FIG. 3 (2), the axial groove 54 is composed of a bottom surface 541 wider than the diameter of the ball 55 and side surfaces 542 and 542 extending upward in a V shape from both ends of the bottom surface 541. ing. The bottom surface 541 is formed orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A as viewed in the cross-section perpendicular to the axis in FIG.

  The leaf spring 56 is substantially parallel to the side surfaces 542 and 542 of the axial groove 54, extends upward in a V shape from the bottom surface 541, and a pair of rolling element side contact portions 562 and 562 that respectively contact the ball 55, and the rolling element side It is comprised by the connection part 561 which connects the radial direction inner end of the contact parts 562 and 562. FIG. The connecting portion 561 is in contact with the bottom surface 541 of the axial groove 54 and is spaced a predetermined distance radially inward from the radially inner end of the ball 55.

  Further, a pair of urging portions 563 and 563 are formed at the upper ends of the rolling element side contact portions 562 and 562, respectively, which are bent outward in a circular arc shape, and downward from the urging portions 563 and 563 toward the bottom surface 541. The groove side surface side contact portions 564 and 564 are formed so as to contact the side surface 542 of the axial groove 54. The urging portions 563 and 563 elastically urge the rolling element side contact portions 562 and 562 and the groove side surface contact portions 564 and 564 in a direction away from each other.

  As shown in FIG. 15, the lengths in the axial direction of the rolling element side contact portions 562 and 562, the biasing portions 563 and 563, the groove side surface contact portions 564 and 564, and the connecting portion 561 of the leaf spring 56 are as described above. The axial length 54 of the axial groove 54 is substantially the same as the axial length L1 (the axial length necessary for the ball 55 to roll in a telescopic operation during a normal driving operation).

  The plate spring 56 is inserted between the axial groove 54 and the ball 55 by being elastically deformed with the vehicle body front end 565 matched with the vehicle body front end 501 of the large-diameter shaft portion 50. Accordingly, in the leaf spring 56, the biasing portions 563 and 563 are mainly elastically deformed to absorb the rotational and radial play between the ball 55 and the axial groove 54 and the axial groove 41.

  There are minute gaps between the cylindrical pins 53A, 53B and the axial grooves 41 and 52. When the female intermediate shaft 16B and the male intermediate shaft 16A are relatively displaced by a slight angle in the rotational direction, the cylindrical pins 53A and 53B come into contact with the axial groove 41 and the axial groove 52.

  However, the leaf spring 56 is inserted in a compressed state between the ball 55 and the substantially trapezoidal axial groove 54, and the leaf spring 56 is inserted between the axial groove 54, the ball 55, and the axial groove 41. An urging force (predetermined preload) due to elastic deformation is applied.

  Therefore, there is no play in the rotational direction or radial direction between the female intermediate shaft 16B and the male intermediate shaft 16A. Further, even if there is an eccentricity or inclination between the female intermediate shaft 16B and the male intermediate shaft 16A, it can be absorbed by the elastic force of the leaf spring 56.

  As shown in FIGS. 15 to 17, the connecting portion 561 is formed with an extension portion 71 that extends further from the vehicle body rear end 566 toward the vehicle body rear side. The extension 71 has a flat plate shape and is formed perpendicular to the normal 161 passing through the axis of the male intermediate shaft 16A when viewed in the cross-section perpendicular to the axis in FIG. Further, the extension portion 71 is configured from the front side of the vehicle body in the order of the inclined extension portion 714 and the parallel extension portion 711. The extension portion 71 is slightly narrower than the width of the connecting portion 561 and has a constant width W. A length L2 is formed parallel to the axis of the shaft 16A.

  That is, there is a gap δ1 between the bottom surface 541 of the axial groove 54 and the parallel extension portion 711 parallel to the bottom surface 541, the vehicle body front end of the parallel extension portion 711, and the vehicle body rear end of the connecting portion 561 are smooth. It is comprised by the inclination extension part 714 to connect. The inclined extension portion 714 is formed in a mountain shape having a vertex 714A that protrudes by a height δ2 radially outward from the radially outer end of the parallel extension portion 711, and extends along the rolling element side contact portions 562 and 562 of the leaf spring 56. Thus, the rolling ball 55 is smoothly guided to the parallel extension 711.

  A folded portion 713 that contacts the bottom surface 541 of the axial groove 54 is formed at the vehicle body rear end of the parallel extension portion 711. A wall 543 orthogonal to the axis of the male intermediate shaft 16A is formed at the vehicle body rear end of the axial groove 54, and the vehicle body rear end of the folded portion 713 is in contact with the wall 543. Accordingly, the parallel extending portion 711 is supported in a both-end supported state with both the vehicle body rear end 566 and the folded portion 713 of the connecting portion 561 as fulcrums.

  The parallel extension 711 elastically deforms and contacts the inner end of the ball 55 in the radial direction, and the elastic force of the inclined extension 714 and the parallel extension 711 causes the ball 55 to move with respect to the axial groove 41 of the female shaft 16B. Preload is applied. Since the parallel extension portion 711 is formed in a flat plate shape orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A, it applies only a radial preload and does not apply a rotational preload.

  That is, during normal driving operation, rotational torque acts between the ball 55 and the axial groove 54 and the axial groove 41, but when the telescopic shaft contracts beyond the contraction distance during normal driving operation, No rotational torque acts between the ball 55 and the axial groove 54 or the axial groove 41.

  For this reason, it is sufficient to apply only the radial preload necessary for the ball 55 to roll smoothly and without backlash, so that the shape of the extension 71 may be a simple flat plate. Accordingly, the axial lengths of the complicated shape portions (rolling body side contact portion 562, urging portion 563, groove side surface side contact portion 564, and connecting portion 561) that need to be manufactured with high accuracy can be the same as the conventional length. Therefore, it is easy to manufacture the leaf spring, and it is not necessary to add a plate spring correction process, and it is possible to minimize an increase in the manufacturing cost of the leaf spring.

  When the male intermediate shaft 16A is moved (contracted) to the left in FIG. 15 with respect to the female intermediate shaft 16B, the ball 55 rotates clockwise, and the ball 55 rolls along the axial groove 54. Move to the rear (right direction) of the car.

  Further, when the male intermediate shaft 16A is moved to the left in FIG. 15 with respect to the female intermediate shaft 16B and exceeds the contraction distance during the normal driving operation, the rolling elements of the leaf spring 56 are sequentially from the ball 55 at the rear end of the vehicle body. After the side contact portion 562, the biasing portion 563, the groove side contact portion 564, and the connecting portion 561 over the vehicle body rear end 566, ride on the inclined extension portion 714, and are guided by the inclined extension portion 714 to get over the vertex 714A. The parallel extension 711 is reached.

  As a result, as shown by a two-dot chain line in FIGS. 15 and 17, the parallel extension portion 711 comes into elastic contact with the radially inner end of the ball 55 and comes into contact with the inclined extension portion 714 and the parallel extension portion 711. Thus, a preload is applied to the ball 55 in the radially outward direction with respect to the axial groove 41 of the female shaft 16B.

  Since the parallel extension portion 711 is supported in a both-sided manner with both the vehicle body rear end 566 and the turn-up portion 713 of the connecting portion 561 as fulcrums, the parallel extension portion 711 is located between the parallel extension portion 711 and the bottom surface 541 of the axial groove 54. Can be reliably set to the predetermined gap δ1, and a constant gap δ1 can be ensured over the entire length of the parallel extension portion 711 in the axial direction. Therefore, variation in the magnitude of the preload applied to each of the plurality of balls 55 is suppressed, and it becomes easy to apply a preload having a predetermined magnitude.

  Therefore, even when the telescopic shaft is contracted beyond a predetermined contraction distance when the steering device is assembled, a preload having a predetermined size can be applied to the ball 55 with respect to the axial groove 41 of the female shaft 16B. Therefore, a smooth contraction operation without play can be performed.

  Next, after the assembly operation is completed, when the male intermediate shaft 16A is moved in the right direction in FIG. 15 with respect to the female intermediate shaft 16B, the ball 55 rotates counterclockwise, and the ball 55 is moved to the parallel extension 711, While rolling along the axial groove 41, the vehicle moves forward (to the left) in the vehicle body.

  Further, when the male intermediate shaft 16A is moved in the right direction in FIG. 15 with respect to the female intermediate shaft 16B, the leaf springs are guided by the inclined extension 714 in order from the ball 55 at the front end of the vehicle body and over the vertex 714A. The rolling element side contact portion 562, the urging portion 563, the groove side surface side contact portion 564, and the vehicle body rear end 566 of the connecting portion 561 are reached.

  Accordingly, when the assembling work is completed and all of the five balls 55 reach the rolling element side contact portion 562, the urging portion 563, the groove side contact portion 564, and the connecting portion 561 of the leaf spring 56, the normal driving operation is performed. At the time of the expansion / contraction operation, the ball 55 rolls, and the expansion / contraction operation of the intermediate shaft 16 is performed smoothly. Further, the rigidity in the rotational direction and the radial direction between the male intermediate shaft 16A and the female intermediate shaft 16B is ensured, and a good steering feeling can be obtained.

  In the fifth embodiment, in the magnitude of the operator's force during the assembly work, the ball 55 passes over the apex 714A of the inclined extension 714 and passes between the vehicle body rear end 566 and the parallel extension 711 side of the connecting part 561. The protrusion height δ2 of the vertex 714A to the outside in the radial direction is set so that it can move.

  Therefore, when the assembly operation of the steering device to the vehicle body 18 is finished and the vehicle 55 runs on the road, the ball 55 moves over the apex 714A of the inclined extension 714 and moves to the parallel extension 711 side. Since it can be prevented, the rigidity in the rotational direction and the radial direction is always ensured, and a good steering feeling is maintained.

  Further, when the completed steering device alone is shipped to the vehicle body assembly factory, the male intermediate shaft 16A is most contracted with respect to the female intermediate shaft 16B beyond the contraction distance during normal driving operation, so that it can be transported. Often the space of the is made small. Even in such a case, it is possible to prevent the ball 55 from moving over the apex 714A of the inclined extension portion 714 and moving toward the vehicle body rear end 566 side due to vibration during transportation.

  Next, a sixth embodiment of the present invention will be described. FIG. 18 is a view corresponding to FIG. 2 showing the expansion / contraction portion of the intermediate shaft according to the sixth embodiment of the present invention. FIG. 19 is an enlarged cross-sectional view of a U portion in FIG. In the following description, the same structural portion and operation as in the above embodiment will be described without any duplication. Further, the same parts as those in the above embodiment will be described with the same numbers.

  Example 6 is a modification of Example 1, and is an example in which Example 3 and Example 4 are combined. That is, FIGS. 18 to 19 show the connecting part of the telescopic shaft of Example 6 of the present invention, and show an example applied to the connecting part of the male intermediate shaft 16A and the female intermediate shaft 16B of the intermediate shaft 16 of FIG. . Moreover, since FIG. 3 of Example 1, FIG. 13 of Example 4, and FIG. 14 (2) are common in Example 5, in description of Example 5, FIG. 3 of Example 1 and FIG. 13 and FIG. 14 (2) are used for explanation.

  As shown in FIGS. 18 to 19, and FIGS. 3, 13, and 14 (2), the rear side of the vehicle body of the female intermediate shaft (female shaft) 16B (the right side in FIG. 18) is the male intermediate shaft (male shaft). ) It is externally fitted and connected to the vehicle body front side of 16A (left side in FIG. 18). The female intermediate shaft 16B is formed in a hollow cylindrical shape, and an axial groove 41 (female shaft side axial groove) 41 having a substantially semicircular cross section at the axis perpendicular to the inner periphery of the inner diameter hole 40 has a telescopic stroke. Six pieces are formed at equal intervals (60-degree intervals) over the entire length.

  The front side of the vehicle body of the male intermediate shaft 16A is formed in a solid cylindrical shape. From the front side of the vehicle body, a large diameter shaft portion 50 having a large diameter and a diameter smaller than that of the large diameter shaft portion 50 are formed. The small-diameter shaft portions 51 are formed in this order.

  A small-diameter cylindrical portion 44 is formed at the vehicle body rear end of the female intermediate shaft 16B, and an inner periphery 421 of a thin cylindrical wiper mounting plate 42 is press-fitted into an outer periphery 441 of the small-diameter cylindrical portion 44. The wiper mounting plate 42 is bent in an L shape toward the axial center of the male intermediate shaft 16A at the vehicle body rear side end surface 442 of the small diameter cylindrical portion 44 to form a bent portion 422.

  A wiper 43 made of rubber or the like is fixed to the bent portion 422. The wiper 43 slides on the outer periphery 511 of the small-diameter shaft portion 51, and dust is generated in the fitting portion between the female intermediate shaft 16B and the male intermediate shaft 16A. Prevents intrusion. The wiper mounting plate 42 is manufactured by pressing a thin steel plate and presses the front end of the vehicle body on the inner periphery 421 of the wiper mounting plate 42 into the outer periphery 441 of the small diameter cylindrical portion 44.

  On the outer periphery of the large diameter shaft portion 50 of the male intermediate shaft 16 </ b> A, three axial grooves (male shaft side axial grooves) 54 having a substantially trapezoidal cross section at the right angle are provided on the front end 501 of the large diameter shaft portion 50. Are formed at equal intervals (120 degree intervals) over substantially the entire axial length of the large-diameter shaft portion 50. The axial groove 54 having a substantially trapezoidal cross section at right angles to the axis is for ball rolling.

  As shown in FIG. 18, the axial length of the axial groove 54 for rolling the ball is formed as a length L3 obtained by adding a length L1 and a length L2. That is, the length L1 is the length in the axial direction necessary for the ball 55 as the rolling element to roll in a telescopic motion during a normal driving operation. The length L2 is an axial length necessary for the ball 55 to roll when the intermediate shaft 16 is contracted beyond the contraction distance during normal driving operation when the steering device is assembled.

  In a space formed by the three axial grooves 54 for ball rolling and the three axial grooves 41 in the same phase of the female intermediate shaft 16B, a plurality of spherical balls (5 balls) as rolling elements 55 are respectively inserted.

  A disc-shaped washer 58, a disc-shaped spring plate 59, and a disc-shaped washer 60 are provided on the small-diameter shaft portion 57 formed at the front end 501 of the large-diameter portion 50 of the male intermediate shaft 16A from the rear side of the vehicle body. They are fitted in order. The front end of the vehicle body of the small-diameter shaft portion 57 is crimped, and a spring plate 59 applies a biasing force toward the vehicle rear side (right side in FIG. 18) to the washer 58 on the vehicle rear side.

  Further, on the outer periphery of the large-diameter shaft portion 50 of the male intermediate shaft 16A, three axial grooves having a substantially semicircular cross-section at a right angle in the middle position between the three axial grooves 54, 54 for ball rolling. (Male shaft side axial groove) 52 is formed to have the same length L3 as the axial length L3 of the axial groove 54 for ball rolling, and is formed at equal intervals (120 degree intervals).

  A solid cylindrical pin as a rotational torque transmitting member is formed in a cylindrical space formed by the three axial grooves 52 of the male intermediate shaft 16A and the three axial grooves 41 of the female intermediate shaft 16B. (Needle rollers) 53A and 53B are inserted. The cylindrical pins 53A and 53B are arranged in series in a cylindrical space formed by the axial groove 52 and the axial groove 41, with the cylindrical pin 53A disposed on the front side of the vehicle body and the cylindrical pin 53B disposed on the rear side of the vehicle body. Has been inserted.

  The columnar pins 53A and 53B are the same parts having the same length in the axial direction, and the length L4 from the vehicle body front end of the columnar pin 53A to the vehicle body rear end of the columnar pin 53B is the axis. The directional groove 52 is formed slightly longer than the axial length L3.

  The outer diameter of the cylindrical pins 53A and 53B is slightly larger than the inner diameter of the cylindrical space formed by the axial groove 52 of the male intermediate shaft 16A and the axial groove 41 of the female intermediate shaft 16B. It has a small diameter.

  The end surface of the washer 58 on the vehicle body rear side is in contact with the vehicle body front end of the cylindrical pin 53A, and has a function as a regulating member that regulates the axial movement of the cylindrical pins 53A and 53B. A wall 521 perpendicular to the axis of the male intermediate shaft 16A is formed at the rear end of the axial groove 52 in the vehicle body, and receives the rear end of the cylindrical pin 53B. In addition, the vehicle body rear end and the vehicle body front end of the cylindrical pins 53A and 53B have a crowning or tapered shape and are reduced in diameter toward the end side.

  A leaf spring (biasing member) 56 as a preload application member is inserted between the three substantially trapezoidal axial grooves 54 and the ball 55. As shown in detail in FIG. 3 (2), the axial groove 54 is composed of a bottom surface 541 wider than the diameter of the ball 55 and side surfaces 542 and 542 extending upward in a V shape from both ends of the bottom surface 541. ing. The bottom surface 541 is formed orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A as viewed in the cross-section perpendicular to the axis in FIG.

  The leaf spring 56 is substantially parallel to the side surfaces 542 and 542 of the axial groove 54, extends upward in a V shape from the bottom surface 541, and a pair of rolling element side contact portions 562 and 562 that respectively contact the ball 55, and the rolling element side It is comprised by the connection part 561 which connects the radial direction inner end of the contact parts 562 and 562. FIG. The connecting portion 561 is in contact with the bottom surface 541 of the axial groove 54 and is spaced a predetermined distance radially inward from the radially inner end of the ball 55.

  Further, a pair of urging portions 563 and 563 are formed at the upper ends of the rolling element side contact portions 562 and 562, respectively, which are bent outward in a circular arc shape, and downward from the urging portions 563 and 563 toward the bottom surface 541. The groove side surface side contact portions 564 and 564 are formed so as to contact the side surface 542 of the axial groove 54. The urging portions 563 and 563 elastically urge the rolling element side contact portions 562 and 562 and the groove side surface contact portions 564 and 564 in a direction away from each other.

  As shown in FIG. 18, the axial lengths of the rolling element side contact portions 562 and 562, the biasing portions 563 and 563, the groove side contact portions 564 and 564, and the connecting portion 561 of the leaf spring 56 are as described above. The axial length L1 of the axial groove 54 is substantially the same as the axial length L1 (the axial length necessary for the ball 55 to roll during a normal operation operation).

  The plate spring 56 is inserted between the axial groove 54 and the ball 55 by being elastically deformed with the vehicle body front end 565 matched with the vehicle body front end 501 of the large-diameter shaft portion 50. Accordingly, in the leaf spring 56, the biasing portions 563 and 563 are mainly elastically deformed to absorb the rotational and radial play between the ball 55 and the axial groove 54 and the axial groove 41.

  There are minute gaps between the cylindrical pins 53A, 53B and the axial grooves 41 and 52. When the female intermediate shaft 16B and the male intermediate shaft 16A are relatively displaced by a slight angle in the rotational direction, the cylindrical pins 53A and 53B come into contact with the axial groove 41 and the axial groove 52.

  However, the leaf spring 56 is inserted in a compressed state between the ball 55 and the substantially trapezoidal axial groove 54, and the leaf spring 56 is inserted between the axial groove 54, the ball 55, and the axial groove 41. An urging force (predetermined preload) due to elastic deformation is applied.

  Therefore, there is no play in the rotational direction or radial direction between the female intermediate shaft 16B and the male intermediate shaft 16A. Further, even if there is an eccentricity or inclination between the female intermediate shaft 16B and the male intermediate shaft 16A, it can be absorbed by the elastic force of the leaf spring 56.

  As shown in FIGS. 13 and 18 to 19, the connecting portion 561 is formed with an extension portion 71 extending further from the vehicle body rear end 566 toward the vehicle body rear side. The extension 71 has a flat plate shape and is formed perpendicular to a normal line 161 passing through the axis of the male intermediate shaft 16A when viewed in the cross section perpendicular to the axis in FIG. Further, the extension portion 71 is configured from the front side of the vehicle body in the order of the inclined extension portion 714 and the parallel extension portion 711. The extension portion 71 is slightly narrower than the width of the connecting portion 561 and has a constant width W. A length L2 is formed parallel to the axis of the shaft 16A.

  That is, there is a gap δ1 between the bottom surface 541 of the axial groove 54 and the parallel extension portion 711 parallel to the bottom surface 541, the vehicle body front end of the parallel extension portion 711, and the vehicle body rear end of the connecting portion 561 are smooth. It is comprised by the inclination extension part 714 to connect. The inclined extension portion 714 is formed in a mountain shape having a vertex 714A that protrudes by a height δ2 radially outward from the radially outer end of the parallel extension portion 711, and extends along the rolling element side contact portions 562 and 562 of the leaf spring 56. Thus, the rolling ball 55 is smoothly guided to the parallel extension 711.

  A protruding portion 544 that protrudes outward in the radial direction is formed at the vehicle body rear end of the bottom surface 541 of the axial groove 54. The protruding portion 544 protrudes radially outward from the bottom surface 541 by the same dimension as the gap δ1 between the parallel extending portion 711 and the bottom surface 541 of the axial groove 54, and contacts the rear end of the parallel extending portion 711 in the vehicle body. Yes. A wall 543 orthogonal to the axis of the male intermediate shaft 16A is formed at the vehicle body rear end of the axial groove 54, and the vehicle body rear end of the parallel extension 711 is in contact with the wall 543. Accordingly, the parallel extension portion 711 is supported in a both-end supported state with both contact points between the vehicle body rear end 566 of the connecting portion 561 and the protruding portion 544 as fulcrums.

  The parallel extension 711 elastically deforms and contacts the inner end of the ball 55 in the radial direction, and the elastic force of the inclined extension 714 and the parallel extension 711 causes the ball 55 to move with respect to the axial groove 41 of the female shaft 16B. Preload is applied. Since the parallel extension portion 711 is formed in a flat plate shape orthogonal to the normal line 161 passing through the axis of the male intermediate shaft 16A, it applies only a radial preload and does not apply a rotational preload.

  That is, during normal driving operation, rotational torque acts between the ball 55 and the axial groove 54 and the axial groove 41, but when the telescopic shaft contracts beyond the contraction distance during normal driving operation, No rotational torque acts between the ball 55 and the axial groove 54 or the axial groove 41.

  For this reason, it is sufficient to apply only the radial preload necessary for the ball 55 to roll smoothly and without backlash, so that the shape of the extension 71 may be a simple flat plate. Accordingly, the axial lengths of the complicated shape portions (rolling body side contact portion 562, urging portion 563, groove side surface side contact portion 564, and connecting portion 561) that need to be manufactured with high accuracy can be the same as the conventional length. Therefore, it is easy to manufacture the leaf spring, and it is not necessary to add a plate spring correction process, and it is possible to minimize an increase in the manufacturing cost of the leaf spring.

  When the male intermediate shaft 16A is moved (contracted) to the left in FIG. 18 with respect to the female intermediate shaft 16B, the ball 55 rotates clockwise, and the ball 55 rolls along the axial groove 54. Move to the rear (right direction) of the car.

  Further, when the male intermediate shaft 16A is moved in the left direction of FIG. 18 with respect to the female intermediate shaft 16B and exceeds the contraction distance during normal driving operation, the rolling elements of the leaf spring 56 are sequentially from the ball 55 at the rearmost end of the vehicle body. After the side contact portion 562, the biasing portion 563, the groove side contact portion 564, and the connecting portion 561 over the vehicle body rear end 566, ride on the inclined extension portion 714, and are guided by the inclined extension portion 714 to get over the vertex 714A. The parallel extension 711 is reached.

  As a result, as shown by a two-dot chain line in FIGS. 18 and 19, the parallel extension 711 is elastically deformed and contacts the radially inner end of the ball 55, and the elastic force of the inclined extension 714 and the parallel extension 711 is obtained. Thus, a preload is applied to the ball 55 in the radially outward direction with respect to the axial groove 41 of the female shaft 16B.

  Since the parallel extension portion 711 is supported in a supported state with both contact points between the vehicle body rear end 566 of the connecting portion 561 and the protruding portion 544 as fulcrums, the parallel extension portion 711 and the bottom surface of the axial groove 54 are supported. It is easy to reliably set the gap with respect to 541 to the predetermined gap δ1, and a constant gap δ1 can be ensured over the entire length of the parallel extension portion 711 in the axial direction. Therefore, variation in the magnitude of the preload applied to each of the plurality of balls 55 is suppressed, and it becomes easy to apply a preload having a predetermined magnitude.

  Therefore, even when the telescopic shaft is contracted beyond a predetermined contraction distance when the steering device is assembled, a preload having a predetermined size can be applied to the ball 55 with respect to the axial groove 41 of the female shaft 16B. Therefore, a smooth contraction operation without play can be performed.

  Next, after the assembly operation is completed, when the male intermediate shaft 16A is moved to the right in FIG. 18 with respect to the female intermediate shaft 16B, the ball 55 is rotated counterclockwise, and the ball 55 is While rolling along the axial groove 41, the vehicle moves forward (to the left) in the vehicle body.

  Further, when the male intermediate shaft 16A is moved to the right in FIG. 18 with respect to the female intermediate shaft 16B, it is guided to the inclined extension portion 714 in order from the ball 55 at the front end of the vehicle body, and after having passed over the apex 714A, the leaf spring The rolling element side contact portion 562, the urging portion 563, the groove side surface side contact portion 564, and the vehicle body rear end 566 of the connecting portion 561 are reached.

  Accordingly, when the assembling work is completed and all of the five balls 55 reach the rolling element side contact portion 562, the urging portion 563, the groove side contact portion 564, and the connecting portion 561 of the leaf spring 56, the normal driving operation is performed. At the time of the expansion / contraction operation, the ball 55 rolls, and the expansion / contraction operation of the intermediate shaft 16 is performed smoothly. Further, the rigidity in the rotational direction and the radial direction between the male intermediate shaft 16A and the female intermediate shaft 16B is ensured, and a good steering feeling can be obtained.

  In the sixth embodiment, in the magnitude of the operator's force during the assembling work, the ball 55 gets over the apex 714A of the inclined extension 714 and passes between the vehicle body rear end 566 and the parallel extension 711 side of the connecting part 561. The protrusion height δ2 of the vertex 714A to the outside in the radial direction is set so that it can move.

  Therefore, when the assembly operation of the steering device to the vehicle body 18 is finished and the vehicle 55 runs on the road, the ball 55 moves over the apex 714A of the inclined extension 714 and moves to the parallel extension 711 side. Since it can be prevented, the rigidity in the rotational direction and the radial direction is always ensured, and a good steering feeling is maintained.

  When shipping the completed steering device alone to the vehicle body assembly factory, the male intermediate shaft 16A is most contracted with respect to the female intermediate shaft 16B beyond the contraction distance during normal driving operation, so that it can be transported. Often the space of the is made small. Even in such a case, it is possible to prevent the ball 55 from moving over the apex 714A of the inclined extension portion 714 and moving toward the vehicle body rear end 566 side due to vibration during transportation.

  In the first to sixth embodiments described above, the example in which the present invention is applied to the intermediate shaft 16 has been described. However, the present invention can be applied to any telescopic shaft constituting the steering device such as the steering shaft 12. Further, in the above embodiment, the vehicle rear side of the female intermediate shaft 16B is externally fitted and connected to the vehicle front side of the male intermediate shaft 16A, but the vehicle body of the male intermediate shaft 16A is connected to the vehicle front side of the female intermediate shaft 16B. The rear side may be fitted and connected.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing a part of a steering apparatus according to the present invention and a part of the steering apparatus, and shows an embodiment applied to an electric power steering apparatus having a steering assist unit. It is an enlarged view of the principal part of FIG. 1 which shows the steering apparatus of Example 1 of this invention, Comprising: It is an enlarged longitudinal cross-sectional view which shows the example applied to the expansion-contraction part of the intermediate shaft. (1) is an AA enlarged sectional view of FIG. 2, and (2) is an enlarged sectional view of the vicinity of the axial groove 54 of FIG. 3 (1). (1) is an BB enlarged sectional view of FIG. 2, and (2) is an enlarged sectional view of the vicinity of the axial groove 54 of FIG. 4 (1). It is a perspective view which shows the leaf | plate spring of Example 1 of this invention. It is the P section expanded sectional view of FIG. FIG. 3 is a view corresponding to FIG. 2 showing an expansion / contraction portion of the intermediate shaft according to the second embodiment of the present invention. It is a perspective view which shows the leaf | plate spring of Example 2 of this invention. It is the Q section expanded sectional view of FIG. It is FIG. 2 equivalent view which shows the expansion-contraction part of the intermediate shaft of Example 3 of this invention. It is the R section expanded sectional view of FIG. It is FIG. 2 equivalent view which shows the expansion-contraction part of the intermediate shaft of Example 4 of this invention. It is a perspective view which shows the leaf | plate spring of Example 4 of this invention. (1) is an enlarged sectional view of the S part in FIG. 12, (2) is an enlarged sectional view taken along the line CC in FIG. 14 (1), and is equivalent to FIG. 4 (2). FIG. 9 is a view corresponding to FIG. 2 showing an expansion / contraction portion of the intermediate shaft according to the fifth embodiment of the present invention. It is a perspective view which shows the leaf | plate spring of Example 5 of this invention. It is T section expanded sectional drawing of FIG. It is FIG. 2 equivalent view which shows the expansion-contraction part of the intermediate shaft of Example 6 of this invention. It is the U section expanded sectional view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Steering wheel 12 Steering shaft 12A Female steering shaft 12B Male steering shaft 13 Steering column 13A Outer column 13B Inner column 14 Support bracket 15 Universal joint 16 Intermediate shaft 161 Normal 16A Male intermediate shaft 16B Female intermediate shaft 17 Universal joint 18 Car body 20 Assist Device 21 Gear housing 23 Output shaft 26 Electric motor 261 Case 30 Steering gear 31 Input shaft 32 Tie rod 40 Inner diameter hole 41 Axial groove (female shaft side axial groove)
42 Wiper Mounting Plate 421 Inner Perimeter 422 Bent Part 43 Wiper 44 Small Diameter Cylindrical Part 441 Outer Periphery 442 Car Body Rear Side End Surface 50 Large Diameter Shaft 501 Car Body Front End 51 Small Diameter Shaft 511 Outer Periphery 52 Axial Groove (Male Shaft Side Axial Groove)
521 Wall 53A, 53B Cylindrical pin (Needle roller)
54 Axial groove (male shaft side axial groove)
541 Bottom 542 Side 543 Wall 544 Protrusion 55 Ball (rolling element)
56 leaf spring 561 connecting portion 562 rolling element side contact portion 563 biasing portion 564 groove side surface contact portion 565 vehicle body front end 566 vehicle body rear end 57 small diameter shaft portion 58 washer 59 spring plate 60 washer 71 extension portion 711 parallel extension portion 712 inclination Extension part 713 Folding part 714 Inclination extension part 714A Vertex

Claims (8)

Male shaft,
Male shaft side axial groove formed on the outer periphery of the male shaft,
A female shaft that is externally fitted to the male shaft so as to be relatively movable in the axial direction and capable of transmitting rotational torque;
On the inner periphery of the female shaft, the female shaft side axial groove formed at the same phase position as the male shaft side axial groove,
A plurality of rolling elements inserted between the male shaft side axial groove and the female shaft side axial groove so as to be capable of rolling in the axial direction;
A leaf spring interposed between the rolling element and the male shaft side axial groove, and applying a preload between the male shaft side axial groove and the female shaft side axial groove via the rolling element; ,
The leaf spring is
A pair of rolling element side contact portions that respectively contact the side surfaces facing the circumferential direction of the rolling element, and apply preload in both the radial direction and the rotational direction to the rolling element,
A pair of groove side contact portions that are arranged apart from each other by a predetermined distance in the circumferential direction with respect to the pair of rolling element side contact portions, and respectively contact the side surfaces of the male shaft side axial groove;
A pair of urging forces that elastically urge the rolling element side contact part and the groove side surface contact part in directions away from each other by connecting the radially outer ends of the rolling element side contact part and the groove side surface contact part. Part,
The radial inner ends of the pair of rolling element side contact portions are connected, arranged in contact with the bottom surface of the male shaft side axial groove, and separated from the radial inner ends of the rolling elements by a predetermined distance radially inward. Connecting part,
The rolling element is formed to extend in the axial direction from the coupling portion, is disposed with a gap between the bottom surface of the male shaft side axial groove, and can contact the inner end in the radial direction of the rolling element. A telescopic shaft, characterized in that it has an extension for applying only a radial preload. The telescopic shaft according to claim 1,
An extension shaft, wherein an extension end in the axial direction of the extension portion contacts a bottom surface of the male shaft side axial groove. In the telescopic shaft according to claim 2,
A telescopic shaft, wherein a folded portion that contacts a bottom surface of the male shaft side axial groove is formed at an axial extension end of the extension portion. In the telescopic shaft according to claim 2,
A telescopic shaft, characterized in that a projecting portion, which is formed on the bottom surface of the male shaft side axial groove and projects outward in the radial direction, comes into contact with the axially extending end of the extending portion. In the telescopic shaft according to any one of claims 2 to 4,
The extension is
A parallel extension formed by extending in the axial direction parallel to the bottom surface of the male shaft side axial groove;
A telescopic shaft comprising an inclined extension part for smoothly connecting a boundary between the connecting part and the parallel extension part. The telescopic shaft according to claim 5,
The inclined extension is
A telescopic shaft, wherein the telescopic shaft is formed in a mountain shape having a vertex projecting radially outward from a radially outer end of the parallel extension portion. In the telescopic shaft according to any one of claims 1 to 6,
The fitting portion between the male shaft and the female shaft has at least a pair of another male shaft side axial groove and a female shaft side at a phase position different from the male shaft side axial groove and the female shaft side axial groove. An axial groove is formed,
A cylindrical pin that transmits rotational torque between the male shaft and the female shaft is inserted into at least one other pair of the male shaft side axial groove and the female shaft side axial groove. Telescopic shaft.   A steering apparatus comprising the telescopic shaft according to any one of claims 1 to 7.

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