JP5316856B2 - Telescopic shaft for vehicle steering and vehicle steering apparatus including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering shaft for a vehicle capable of preventing the deterioration of steering feeling, and a steering device for a vehicle provided with the same. <P>SOLUTION: A male serration 27 of an inner shaft 10 and a female serration 29 of an outer shaft 11 in the steering shaft 3 are engaged with each other when a relative phase of both the shafts 10 and 11 exceeds a prescribed range. A resin rod 41 supports both the shafts 10 and 11 with each other in floating states in a peripheral direction C when the relative phase of both the shafts 10 and 11 is in the prescribed range. When viewed along an axial direction, the resin rod 41 is brought into contact with the inner shaft 10 and the outer shaft 11 at first to fourth contact points 81 to 84. When viewed along the axial direction, an intersection F of a first line E1 for connecting the first and fourth contact points 81 and 84 and a second line E2 for connecting the second and third contact points 82 and 83 is arranged on a pitch circle D on which the male serration 27 and the female serration 29 are engaged with each other. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a vehicle steering telescopic shaft and a vehicle steering apparatus including the same.

  Some telescopic shafts for vehicles such as a steering shaft include an inner shaft and an outer shaft that are fitted so as to be relatively movable in the axial direction (see, for example, Patent Document 1). When the transmission torque between the inner shaft and the outer shaft is less than or equal to a predetermined value, the telescopic shaft of Patent Document 1 is configured such that both shafts are elastically connected in the rotational direction, and the transmission torque is a predetermined value. When the value exceeds, both shafts are rigidly connected in the rotational direction.

Specifically, a rolling element is disposed on a leaf spring mounted in an axial groove formed on the outer periphery of the inner shaft, and the rolling element is formed in an axial groove formed on the inner periphery of the outer shaft. Is elastically pressed. When the torque of both shafts is less than or equal to a predetermined value, the torque acting on the outer shaft is transmitted from the rolling elements to the leaf spring, and is transmitted to the inner shaft while bending the leaf spring. When the torque between both shafts exceeds a predetermined value, the ridges formed on the inner shaft and the ridges formed on the outer shaft mesh with each other, and both shafts are rigidly connected.
JP 2005-1114068 A

Here, in the steering device having the tilt mechanism, after adjusting the tilt position of the steering wheel, the rotation axis of the outer shaft and the rotation axis of the inner shaft are inclined from the axis of the steering shaft connecting the universal joint and the steering wheel. It will be.
In such a case, the outer shaft and the inner shaft are elastically supported. However, when the steering wheel is rotated (steered), the two shafts are separated from each other by the outer shaft, the leaf spring, and the rolling between them. While a rigid fitting without rattling by the moving body is generated, a movement to return both rotational axes deviating from the central axis of the steering shaft to the original state occurs, so that the pulsation of the rotational torque of the steering wheel increases.

As shown in FIG. 10, this is perceived as an unnatural torque fluctuation from the steering wheel to the driver, giving a sense of incongruity to steering and impairing the steering feeling. However, if the rigid connection is lost, transmission torque loss due to rattling or twisting of both shafts occurs, and the steering feeling is reduced.
Moreover, it is desirable that the outer shaft and the inner shaft that are relatively movable in the axial direction can also be used as a telescopic steering shaft in terms of convenience and cost.

  The present invention has been made under such background, and includes a vehicle steering telescopic shaft capable of preventing a reduction in steering feeling even when the central axes of the inner shaft and the outer shaft are inclined with respect to each other after tilt adjustment or the like. An object of the present invention is to provide a vehicle steering apparatus.

In order to achieve the above-described object, the present invention enables the vehicle steering telescopic shaft (3) rotating in response to the steering of the steering member (2) to be slidable in the axial direction (S) and to transmit torque to each other. The inner shaft (10) and the cylindrical outer shaft (11) fitted together, the plurality of male teeth (27) formed on the outer peripheral surface (26) of the inner shaft, and the inner peripheral surface (28) of the outer shaft A plurality of formed female teeth (29) are included, and when the relative phase of both axes exceeds a predetermined range, both the axes are rigidly connected in the circumferential direction (C) by meshing of the male teeth and female teeth. A rigid coupling element (25), and at least three pairs of axial grooves (31, 32; 33, 34; 35, 36) formed on each of the outer peripheral surface of the inner shaft and the inner peripheral surface of the outer shaft and facing each other. , Interposed between the pair of axial grooves in a four-point contact state, and the relative phase of the inner shaft and the outer shaft is predetermined. When the囲内, the tree Aburabo (41, 42, 43) as a plurality of elastic connecting element for supporting one of the two axes in a floating form in the circumferential direction relative to the other, wherein the axial of the inner shaft When viewed along, each of the resin rods contacts the axial groove of the inner shaft at two points at the first and second contact points (81, 82), and the second resin rod contacts the axial groove of the outer shaft. Two points of contact at the third and fourth contact points (83, 84), and when viewed along the axial direction of the inner shaft, the line (E1) connecting the first and fourth contact points and the second And the intersection (F) with the line (E2) connecting the third contact points is arranged on the pitch circle (D) of the engagement between the male teeth and the female teeth (claim). 1).

  According to the present invention, after the tilt adjustment or the like, when the torque is not acting between the inner shaft and the outer shaft, the relative phases of both the shafts are within a predetermined range. In addition, both shafts are in a state of being bent by mutual connection of the resin rods by their own weights, and the central axes of both shafts are inclined with respect to each other. Here, when viewed along the axial direction of the inner shaft in a cross section including the intersection of the central axes of the two axes and perpendicular to the central axis of the inner shaft, a line connecting the first and fourth contact points, Since the intersection point with the line connecting the third contact points is arranged on the pitch circle, the rigidity of the connection between the two shafts via the resin rod can be made moderate and not too high and too low. As a result, when torque is applied between the two shafts from the folded state, the central axes of both shafts can be arranged in a straight line so that the folded state can be eliminated. It can be prevented that the core rotates due to rotation. Thereby, it is possible to prevent the transmission torque at the time of rotation of both shafts from fluctuating so as to pulsate, thereby preventing the steering feeling from being lowered. Furthermore, since the rigidity of the connection between both shafts via the resin rod can be set to an appropriate value that is not too low, it is possible to prevent rattling or twisting between the two shafts. As a result, since the torque cross can be reduced, it is possible to prevent a decrease in steering feeling when both shafts rotate.

  Further, when the relative phase between the inner shaft and the outer shaft is within a predetermined range, when a torque acts between the inner shaft and the outer shaft, each resin rod is hardly twisted with respect to the corresponding axial groove ( It is elastically compressed (without sliding contact). As a result, the loss in transmitting torque between the two shafts via each resin rod can be remarkably reduced, and as a result, smooth torque transmission can be achieved when the relative phase between the inner shaft and the outer shaft is within a predetermined range. Can be achieved. An uncomfortable feeling can be suppressed in torque transmission between the inner shaft and the outer shaft, and a reduction in steering feeling can be reliably suppressed.

  In the present invention, each of the resin rods has a U-shaped cross section, and may include a groove (50) opened in one radial direction of the inner shaft (claim 2). In this case, the flexibility of the resin rod can be increased when torque acts between both shafts. As a result, torque can be transmitted smoothly when torque is transmitted from one shaft to the other shaft via each resin rod, and sudden changes in torque transmission between the two shafts can be prevented. Thereby, a more natural steering feeling can be realized.

  Further, in the present invention, when viewed along the axial direction of the inner shaft, the contact angle (H1) between the axial groove of the inner shaft and the resin rod at the first contact point is the fourth contact point. The contact angle (H4) between the axial groove on the outer shaft and the resin rod is equal to the contact angle (H2) between the axial groove on the inner shaft and the resin rod at the second contact point. The contact angle (H3) between the axial groove of the outer shaft and the resin rod at the third contact point may be made equal (Claim 3).

  In this case, the direction of the force acting on the second contact point and the direction of the force acting on the third contact point when the two shafts rotate in one direction of rotation and a torque acts between the two shafts. Can be reversed. In addition, when both shafts rotate in the other direction of rotation and a torque acts between both shafts, the direction of the force acting on the first contact point and the direction of the force acting on the fourth contact point You can do the opposite. As a result, it is possible to more reliably prevent the resin rods from being twisted with respect to both shafts even when the vehicle steering telescopic shaft rotates in any direction.

In addition, the present invention provides a vehicle steering apparatus (1) characterized by including the vehicle steering telescopic shaft that rotates in accordance with the steering of the steering member. In this case, it is possible to realize a vehicle steering apparatus that is excellent in steering feeling.
In the above description, numbers in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of a vehicle steering apparatus 1 including a vehicle steering telescopic shaft according to an embodiment of the present invention. Referring to FIG. 1, a vehicle steering apparatus 1 includes a tilt adjustment function for adjusting the position of a steering member 2 such as a steering wheel substantially up and down with respect to the driver, and the position of the steering member 2 to the driver. In contrast, it has both telescopic adjustment functions for adjusting the front and rear.

The vehicle steering apparatus 1 includes a steering member 2 and a steering shaft 3 that is connected to the steering member 2 and rotates according to the steering of the steering member 2 as a vehicle steering telescopic shaft.
The steering member 2 is attached to one end of the steering shaft 3. The steering shaft 3 is disposed so as to be inclined so that one end to which the steering member 2 is attached is on the upper side (upper side). The other end of the steering shaft 3 is connected to a steering mechanism 7 via a universal joint 4, an intermediate shaft 5 and a universal joint 6.

  The steering mechanism 7 includes a pinion shaft 8 connected to the universal joint 6, and a rack shaft 9 having rack teeth 9 a that mesh with a pinion 8 a at one end of the pinion shaft 8. When the steering member 2 is rotated to rotate the steering shaft 3, the pinion 8 a of the steering mechanism 7 rotates, and this rotational motion is converted into a linear motion in the longitudinal direction of the rack shaft 9. As a result, the knuckle arm is rotated via a tie rod (not shown) connected to the rack shaft 9 to steer the steered wheels.

The steering shaft 3 has a cylindrical outer shaft 11 to which the steering member 2 is attached at one end, and one end 10a that is fitted to the other end 11b of the outer shaft 11 so as to be able to transmit torque and be slidable in the axial direction. And a rod-shaped inner shaft 10. The universal joint 4 is connected to the other end of the inner shaft 10.
The inner shaft 10 has a central axis A, and the outer shaft 11 has a central axis B. The steering shaft 3 has a center axis Q. The center axis Q of the steering shaft 3 is an axis connecting the other end 10b of the inner shaft 10 and one end 11a of the outer shaft 11, and when the center axes A and B of both the shafts 10 and 11 coincide with each other, The central axis Q of the steering shaft 3 also coincides.

Hereinafter, the axial direction S of the inner shaft 10 is simply referred to as the axial direction S, the circumferential direction C of the inner shaft 10 is simply referred to as the circumferential direction C, and the radial direction R of the inner shaft 10 is simply referred to as the radial direction R.
The steering shaft 3 is rotatably supported by the column tube 12. The column tube 12 includes an outer cylinder 13 that surrounds the outer shaft 11, and an inner cylinder 14 that is fitted so as to be slidable relative to the outer cylinder 13 and surrounds the inner shaft 10. The outer cylinder 13 supports one end of the outer shaft 11 via a bearing 15 so as to be rotatable and movable in the axial direction S. The inner cylinder 14 supports the intermediate part of the inner shaft 10 via the bearing 16 so as to be rotatable and relatively unmovable in the axial direction S.

A first bracket 17 is fixed to the inner cylinder 14. The first bracket 17 is supported by a second bracket 19 fixed to the vehicle body 18 via a support shaft 20. The inner cylinder 14 can swing around the support shaft 20.
A third bracket 21 is fixed to the outer cylinder 13. The third bracket 21 faces the fourth bracket 22 fixed to the vehicle body 18. The third bracket 21 is locked to the fourth bracket 22 by the lock mechanism 23.

  By operating the operation lever 24 of the lock mechanism 23, the lock can be released. By releasing the lock, the outer cylinder 13 and the outer shaft 11 can be telescopically moved relative to the corresponding inner cylinder 14 and inner shaft 10 in the axial direction. Further, by releasing the lock, it is possible to perform a tilting operation that swings the steering shaft 3 and the column tube 12 around the support shaft 20.

FIG. 2 is an exploded perspective view of the main part of the steering shaft 3. FIG. 3 is a cross-sectional view of a main part of the steering shaft 3. 4 is a cross-sectional view taken along line IV-IV in FIG. 3 is a cross-sectional view taken along line III-III in FIG.
With reference to FIG. 2, the inner shaft 10 and the outer shaft 11 of the steering shaft 3 are metal high-rigidity members, respectively. The inner shaft 10 and the outer shaft 11 are provided with serrations 25 as rigid connecting elements. The serration 25 rigidly connects the shafts 10 and 11 in the circumferential direction C when the relative phase between the inner shaft 10 and the outer shaft 11 (relative position in the circumferential direction C) exceeds a predetermined range.

The serration 25 includes a plurality of male serrations 27 as a plurality of male teeth provided on the outer peripheral surface 26 of the one end 10 a of the inner shaft 10 and a plurality of females provided on the inner peripheral surface 28 of the other end 11 b of the outer shaft 11. A plurality of female serrations 29 as teeth.
With respect to the circumferential direction C, the male serration 27 is formed over the entire area of the inner shaft 10 except for axial grooves 31, 33 and 35 described later, and the female serration 29 is formed of an axial groove 32 described later of the outer shaft 11. , 34 and 36 are formed over the entire area. These serrations 27 and 29 extend in parallel to the axial directions of the corresponding inner shaft 10 and outer shaft 11, respectively.

  2 and 4, the inner shaft 10 is inserted into the outer shaft 11 so that the central axis A of the inner shaft 10 and the central axis B of the outer shaft 11 substantially match, and the male serration 27 and Female serrations 29 can mesh with each other. Each male serration 27 and each female serration 29 are arranged coaxially. When viewed along the axial direction S, each male serration 27 and the corresponding female serration 29 can mesh with each other on a predetermined pitch circle D. The central axis of the pitch circle D coincides with the central axes A and B where the central axis A of the inner shaft 10 and the central axis B of the outer shaft 11 overlap.

Referring to FIGS. 3 and 4, at least three pairs (in the present embodiment) facing each other are arranged on outer peripheral surface 26 of one end 10 a of inner shaft 10 and inner peripheral surface 28 of the other end 11 b of outer shaft 11. , Three pairs) axial grooves 31, 32; 33, 34; 35, 36 are formed. Each of the axial grooves 31 to 36 extends in parallel with the axial direction of the corresponding inner shaft 10 and outer shaft 11.
More specifically, three axial grooves 31, 33, and 35 are formed at equal intervals along the circumferential direction C on the outer peripheral surface 26 of the one end 10 a of the inner shaft 10. Each of the axial grooves 31, 33, and 35 includes a groove bottom 70 and first and second inclined surfaces 71 and 72 that are arranged in the circumferential direction C with the groove bottom 70 interposed therebetween.

  The groove bottom 70 is formed on a flat surface extending in parallel with the axial direction S. The groove bottom 70 may be formed in a circular arc surface that is convex inward in the radial direction R. The first and second inclined surfaces 71 and 72 are formed in a tapered shape as a whole, and are spaced apart from each other as they proceed outward in the radial direction R. The first and second slopes 71 and 72 are formed on flat surfaces, but may be formed on curved surfaces. Regarding one side C <b> 1 in the circumferential direction C, the first slope 71 and the second slope 72 are arranged in this order from the upstream side.

Three axial grooves 32, 34 and 36 are formed on the inner peripheral surface 28 of the other end 11 b of the outer shaft 11 at equal intervals along the circumferential direction of the outer shaft 11. Each axial groove 32, 34, 36 includes a groove bottom 75 and third and fourth inclined surfaces 73, 74 arranged in the circumferential direction C across the groove bottom 75.
The groove bottom 75 is formed in a circular arc surface that is convex outward in the radial direction of the outer shaft 11. The groove bottom 75 may be formed on a flat surface. The third and fourth inclined surfaces 73 and 74 are formed in a tapered shape as a whole, and the interval between the third and fourth inclined surfaces 73 and 74 is increased as they proceed inward in the radial direction of the outer shaft 11. The third and fourth inclined surfaces 73 and 74 are formed on flat surfaces, but may be formed on curved surfaces. Regarding one side C <b> 1 in the circumferential direction C, the third slope 73 and the fourth slope 74 are arranged in this order from the upstream side.

2 and 3, a synthetic resin resin body 39 is interposed between the inner shaft 10 and the outer shaft 11. The resin body 39 is an integrally molded product, and includes a plurality of long resin rods 41, 42, and 43 as elastic connection elements, and a connecting portion 44 that connects these resin rods 41, 42, and 43. Yes.
The connection part 44 includes a main part 45 having a disk shape. An insertion hole 46 is formed in the main body 45. A cylindrical protrusion 47 protruding from one end surface of the inner shaft 10 is inserted into the insertion hole 46. A push nut 48 is attached to the protrusion 47, and the main portion 45 of the connecting portion 44 is sandwiched and fixed by the push nut 48 and one end surface of the inner shaft 10.

The push nut 48 has a disk shape, and a peripheral edge portion of the insertion hole 49 formed in the central portion in the radial direction is raised. The protrusion 47 is inserted into the insertion hole 49. The peripheral edge of the insertion hole 49 is locked to the protrusion 47. The tip of the protrusion 47 extends in the radial direction of the inner shaft 10.
Referring to FIGS. 2 and 4, each resin rod 41, 42, 43 extends from main body 45 of connecting portion 44 in parallel with axial direction S. These resin rods 41, 42, 43 straddle between a pair of corresponding axial grooves 31, 32; 33, 34; 35, 36, respectively.

Each resin rod 41, 42, 43 is fitted (press-fit) between a corresponding pair of axial grooves 31, 32; 33, 34; 35, 36, and is elastically deformed by being compressed. . When the relative phase between the inner shaft 10 and the outer shaft 11 is within a predetermined range, torque is transmitted between the inner shaft 10 and the outer shaft 11 via these resin rods 41, 42, 43.
The length of each resin rod 41, 42, 43 is equal. A groove 50 is formed in each resin rod 41, 42, 43. The groove 50 extends along the longitudinal direction L of the resin rods 41, 42, 43 in which the groove 50 is formed. The longitudinal direction L and the axial direction S are parallel. Each resin rod 41, 42, 43 has a U-shaped cross section that opens outward in the radial direction R of the inner shaft 10.

  In addition, since the resin rods 41, 42, and 43 have the same configuration, the resin rod 41 is mainly described below among the resin rods 41 to 43. In addition, since the axial grooves 31, 33, and 35 of the inner shaft 10 have the same configuration, the axial groove 31 is mainly described among the axial grooves 31, 333, and 35 below. . In addition, since the axial grooves 32, 34, and 36 of the outer shaft 11 have the same configuration, the axial groove 32 is mainly described below among the axial grooves 32, 34, and 36. .

  FIG. 5 is an enlarged view of a main part of FIG. In addition, when it demonstrates with reference to FIG. 5, it demonstrates based on the state seen along the axial direction S. FIG. Referring to FIG. 5, the axial grooves 31, 32 and the resin rod 41 have a symmetrical shape with a center axis A of the inner shaft 10 and a plane J passing through an intersection point F described later as the center. A gap M is formed between the groove bottom 70 of the axial groove 31 of the inner shaft 10 and the outer peripheral surface of the resin rod 41, and is used as a refuge for the resin rod 41 when the resin rod 41 is elastically deformed. Yes.

The groove 50 is formed in a U-shaped cross section and is opened outward in the radial direction R. The outer peripheral surface of the resin rod 41 includes an arc surface 54. The arc surface 54 is an arc surface having a substantially single curvature radius in a free state where no torque acts between the shafts 10 and 11.
The arc surface 54 is in contact with the first to fourth inclined surfaces 71 to 74 of the axial grooves 31 and 32 in a four-point contact state. The arc surface 54 is in line contact with each of the first to fourth inclined surfaces 71 to 74, and the contact portion between the arc surface 54 and the first to fourth inclined surfaces 71 to 74 is parallel to the axial direction S. It extends.

When viewed along the axial direction S, the arc surface 54 of the resin rod 41 is in contact with the first inclined surface 71 at the first contact point 81 and is in contact with the second inclined surface 72. 82 is in contact with the third inclined surface 73 at the third contact point 83, and is in contact with the fourth inclined surface 74 at the fourth contact point 84.
Thus, when viewed along the axial direction S, the arc surface 54 of the resin rod 41 contacts the axial groove 31 of the inner shaft 10 at two points at the first and second contact points 81 and 82. In addition, the third and fourth contact points 83 and 84 are in contact with the axial groove 32 of the outer shaft 11 at two points.

One of the features of the present embodiment is that the first line E1 that connects the first and fourth contact points 81 and 84, and the second line E2 that connects the second and third contact points 82 and 83, Is at a point arranged on the pitch circle D.
In the first line E1, the distance G1 between the first contact point 81 and the intersection point F is equal to the distance G1 ′ between the intersection point F and the fourth contact point 84 (G1 = G1 ′). Further, the distance G2 between the second contact point 82 and the intersection point F is equal to the distance G2 ′ between the intersection point F and the third contact point 83 (G2 = G2 ′).

At the first contact point 81, the first inclined surface 71 and the arc surface 54 of the resin rod 41 form a first contact angle H1. The first contact angle H1 is an angle formed by a plane J passing through the central axis A and the intersection F of the inner shaft 10 and an action line of the resultant force K1 transmitted to the circular arc surface 54 by the first inclined surface 71.
At the fourth contact point 84, the fourth inclined surface 74 and the arc surface 54 of the resin rod 41 form a fourth contact angle H4. The fourth contact angle H4 is an angle formed by the plane J and the line of action of the resultant force K4 transmitted to the circular arc surface 54 by the fourth inclined surface 74.

The first contact angle H1 and the fourth contact angle H4 are equal. As a result, the resultant forces K1, K4 are directed in opposite directions so as to approach each other.
At the second contact point 82, the second inclined surface 72 and the arc surface 54 of the resin rod 41 form a second contact angle H2. The second contact angle H <b> 2 is an angle formed by the plane J and the line of action of the resultant force K <b> 2 of the force transmitted to the circular arc surface 54 by the second inclined surface 72.

When viewed along the axial direction S, at the third contact point 83, the third inclined surface 73 and the arc surface 54 of the resin rod 41 form a third contact angle H3. The third contact angle H3 is an angle formed by the plane J and the line of action of the resultant force K3 transmitted to the circular arc surface 54 by the third inclined surface 73.
The second contact angle H2 and the third contact angle H3 are made equal. As a result, the resultant forces K2 and K3 are directed in opposite directions so as to approach each other.

  By operating the steering member, when the inner shaft 10 and the outer shaft 11 rotate in one of the circumferential directions C1, torque is transmitted from the outer shaft 11 to the inner shaft 10. At this time, the resultant force K3 acts on the third contact point 83 from the third slope 73 of the outer shaft 11, and the resultant force K2 acts as a reaction force on the second contact point 82 from the second slope 72 of the inner shaft 10. Works. Each resin rod 41, 42, 43 is elastically deformed as a U-shaped spring by receiving these resultant forces K2, K3.

  Further, by operating the steering member, when the inner shaft 10 and the outer shaft 11 rotate in the other direction C2 in the circumferential direction C, torque is transmitted from the outer shaft 11 to the inner shaft 10. At this time, the resultant force K4 acts on the fourth contact point 84 from the fourth inclined surface 74 of the outer shaft 11, and the resultant force K1 is applied as a reaction force from the first inclined surface 71 of the inner shaft 10 to the first contact point 81. Works. Each resin rod 41, 42, 43 is elastically deformed as a U-shaped spring by receiving these resultant forces K1, K4.

With the above configuration, when the steering angle θ of the steering member is −θ1 ≦ θ ≦ θ1 (θ1 is a predetermined steering angle, for example, about several minutes), the relative phases of both shafts 10 and 11 are predetermined. Is in range. When the steering angle θ is zero, the steering is neutral. Further, the steering angle θ is positive with respect to one C1 in the circumferential direction C and negative with respect to the other C2 in the circumferential direction C.
At this time, with respect to both the circumferential direction C and the radial direction R, the shafts 10 and 11 are elastically supported (supported in a floating manner) by the resin rods 41, 42, and 43 (only the resin rod 41 is shown in FIG. 5). The male serration 27 and the female serration 29 do not mesh with each other. Each resin rod 41, 42, 43 is compressed and elastically deformed between the inner shaft 10 and the outer shaft 11.

For example, when the steering member (outer shaft 11) is operated in one direction C1 in the circumferential direction C and the absolute value of the steering angle θ increases, the resin rods 41, 42, and 43 are compressed in the circumferential direction C, as shown in FIG. As shown in FIG. Thereby, torque is transmitted from the axial groove 32 of the outer shaft 11 to the axial groove 31 of the inner shaft 10 via the third contact point 83 and the second contact point 82 of the resin rod 41.
By satisfying θ1 <θ, when the relative phase between the two axes 10 and 11 exceeds a predetermined range, there is no gap between the corresponding serration portions 27 and 29. As a result, the male serration 27 and the female serration 29 mesh with each other, and both shafts 10 and 11 can transmit torque rigidly via the serration portions 27 and 29.

  Similarly, when the steering member is operated in the other direction C2 in the circumferential direction C, the fourth contact point of the resin rod 41 from the axial groove 32 of the outer shaft 11 when the steering angle θ is −θ1 ≦ θ ≦ θ1. Torque is transmitted to the axial groove 31 of the inner shaft 10 via 84 and the first contact point 81. By satisfying θ <−θ1, the male serration 27 and the female serration 29 mesh with each other when the relative phase between the two axes 10 and 11 exceeds a predetermined range.

  FIG. 7 is a schematic view of a main part when the shafts 10 and 11 are fitted so as to be bent halfway. Referring to FIG. 7, in a steering neutral state in which the torque is not applied between the inner shaft 10 and the outer shaft 11 and the steering angle θ as the rotation angle of the steering member 2 is zero. At a certain time, both shafts 10 and 11 are in a bent state in which they are bent at one end 10a of the inner shaft 10 and the other end 11b of the outer shaft 11 by their own weight. Although exaggerated in FIG. 5, the actual inclination angles of the central axes A and B are a slight value of several degrees or less.

At this time, the central axes A and B of both the shafts 10 and 11 are inclined with respect to each other and are inclined with respect to the central axis Q of the steering shaft 3. The center axes A and B of both shafts 10 and 11 form an intersection W by intersecting at one end 10a of the inner shaft 10. The cross-sectional shape in the orthogonal plane V including the intersection W and orthogonal to the inner shaft 10 is the same as that in FIG.
When both shafts 10 and 11 are in a bent state and the relative phases of both shafts 10 and 11 are within a predetermined range, both the absolute values of the steering angle θ increase between zero and θ1, As shown in FIG. 8, the central axes A and B of both shafts 10 and 11 are aligned in a straight line. Thus, in a state where both shafts 10 and 11 are aligned straight, both shafts 10 and 11 are rigidly connected by serration.

In this way, with the shafts 10 and 11 aligned in a straight line, the steering member 2 is rotated once to the locked state on one side C1 or the other side C2 in the circumferential direction C, and then the steering member 2 is compared by lock-to-lock. FIG. 9 shows the relationship between the steering angle θ and the torque generated in the steering member 2 when the reciprocating rotation is performed quickly and appropriately.
Note that θ2 is an allowable value (lock angle) of the steering angle θ2 with respect to one C1 in the circumferential direction C, and −θ2 is an allowable value (lock angle) of the steering angle θ2 with respect to the other C2 in the circumferential direction C. As shown in FIG. 9, the pulsating change of the torque T is very small with respect to the change of the steering angle θ, so that the steering of the steering member 2 does not feel uncomfortable.

In the case of the comparative example in which both shafts are rotated in a state where they are not aligned straight, the relationship between the steering angle and the torque generated in the steering member is different from the characteristics of the steering shaft 3 shown in FIG. It will be shown in In this case, the pulsation width ΔT as a pulsating change of the torque T is large with respect to the change of the steering angle θ, and the steering member feels uncomfortable.
Referring to FIG. 8, the other end 10 b of the inner shaft 10 is restricted by the frictional resistance of each member on the steered wheel 60 side such as the universal joint 4, the intermediate shaft 5, the steering mechanism 7, and the steered wheel 60. FIG. 11 shows the relationship between the steering angle θ and the torque T (twist of the steering shaft 3). As shown in FIG. 11, as the absolute value of the steering angle θ increases from zero, the torque T (twist of the steering shaft 3) increases approximately linearly.

  Further, when the absolute value of the steering angle θ becomes a predetermined angle θ ′ larger than θ1 and the torque T becomes a predetermined value T ′, the torque T ′ is turned to the steered wheels 60 with respect to the other end 10 b of the inner shaft 10. It becomes equal to the sum of the frictional resistances of the respective members on the side. From this point, the steering angle θ ′ and torque T ′ in the waveform of FIG. 9 are transferred, and the steering shaft 3 rotates the universal joint 4 and the like against the frictional resistance of each of the above members according to the graph of FIG. The steered wheel 60 is steered.

As shown in FIG. 11, when the steering angle is very small, the relationship between the steering angle θ in the present embodiment and the torque acting on the steering shaft 3 can be made substantially linear. It can be close to the ideal graph shown.
Therefore, as the absolute value of the steering angle θ increases from zero, the torque increases approximately linearly, and a natural steering feeling can be realized. When the steering angle θ is −θ1 ≦ θ ≦ θ1, the torque is substantially zero, and when the angle θ <−θ1 or θ1 <θ, the torque does not suddenly increase. As a result, it is possible to prevent steering fluctuations near the steering neutral position.

  As described above, according to the present embodiment, after the tilt adjustment, when the torque T is not acting between the inner shaft 10 and the outer shaft 11, the relative phases of the shafts 10 and 11 are within a predetermined range. It is in. In addition, both the shafts 10 and 11 are in a bent state in which the connecting portions (one end 10 a and the other end 11 b) via the resin rods 41, 42 and 43 hang down due to their own weight and the like. The axes A and B are inclined with respect to each other.

  Here, in the cross section in the orthogonal plane V, the first line E1 connecting the first and fourth contact points 81 and 84 and the second line E2 connecting the second and third contact points 82 and 83 are shown. Since the intersection point F is arranged on the pitch circle D in the orthogonal plane V, the rigidity of the connection between the shafts 10 and 11 via the resin rods 41, 42 and 43 is not too high and not too low. Can be anything.

  As a result, when the torque T acts between the shafts 10 and 11 from the folded state, it is possible to cancel the folded state by arranging the central axes A and B of the shafts 10 and 11 in a straight line. As a result, it is possible to prevent the shafts 10 and 11 from rotating while the shafts 10 and 11 are in a bent state and to swing, and to prevent the transmission torque during the rotation of the shafts 10 and 11 from changing in a pulsating manner. Can be prevented.

  Furthermore, the intersection F between the first line E1 and the second line E2 is arranged on the pitch circle D in the orthogonal plane V. Thereby, the rigidity of the connection of both shafts 10 and 11 through the resin rods 41, 42 and 43 is set to an appropriate value which is not too low. Thereby, it is possible to prevent rattling or twisting between the shafts 10 and 11. As a result, since the torque cross can be reduced, it is possible to prevent a reduction in steering feeling when the shafts 10 and 11 are rotated.

  When the torque acting between the inner shaft 10 and the outer shaft 11 is relatively small, the relative phase between the inner shaft 10 and the outer shaft 11 is within a predetermined range. At this time, the inner shaft 10 and the outer shaft 11 are elastically connected in the circumferential direction C via the resin rods 41, 42, 43. An intersection F between the first line E1 connecting the first and fourth contact points 81 and 84 and the second line E2 connecting the second and third contact points 82 and 83 is on the pitch circle D. Placed in.

As a result, when the relative phase between the inner shaft 10 and the outer shaft 11 is within a predetermined range, when a torque acts between the inner shaft 10 and the outer shaft 11 as the steering member 2 is operated, each resin rod 41 , 42, 43 are elastically compressed with little twisting (no sliding contact) with the corresponding axial grooves 31, 32; 33, 34; 35, 36.
Thereby, the loss at the time of transmitting torque between the both shafts 10 and 11 through the resin rods 41, 42 and 43 can be remarkably reduced, and as a result, the relative phase between the inner shaft 10 and the outer shaft 11 is within a predetermined range. When inside, smooth torque transmission can be achieved. It is possible to suppress an uncomfortable feeling in torque transmission between the inner shaft 10 and the outer shaft 11, and to reliably suppress a decrease in steering feeling. Further, since wear due to sliding contact of the resin rods 41, 42, 43 can be suppressed, durability of the steering shaft 3 can be improved through improvement of durability of the resin rods 41, 42, 43.

  Further, each resin rod 41, 42, 43 is formed in a U-shaped cross section having a groove 50. With such a configuration, the flexibility of the resin rods 41, 42, and 43 when torque acts between the shafts 10 and 11 can be increased. As a result, when torque is transmitted from one of the shafts 10 and 11 to the other through the resin rods 41, 42 and 43, the torque can be transmitted smoothly. Can be prevented from occurring. Thereby, a more natural steering feeling can be realized.

  Further, when viewed along the axial direction S, the first contact angle H1 and the fourth contact angle H4 are equal to each other, and the second contact angle H2 and the third contact angle H3 are mutually equal. Are equal. As a result, both shafts 10 and 11 rotate in one direction C1 in the circumferential direction C, and when a torque acts between both shafts 10 and 11, the direction of the resultant force K2 acting on the second contact point 82, and the third The direction of the resultant force K3 acting on the contact point 83 can be reversed.

  Similarly, the direction of the resultant force K1 acting on the first contact point 81 when the shafts 10 and 11 rotate in the other direction C2 in the circumferential direction C and torque is applied between the shafts 10 and 11, and the fourth The direction of the resultant force K4 acting on the contact point 84 can be reversed. As a result, even when the steering shaft 3 rotates in any of the circumferential directions C, the resin rods 41, 42, 43 can be more reliably prevented from being twisted with respect to both the shafts 10, 11.

  Further, a gap M is formed between the groove bottom 70 of each axial groove 31, 33, 35 of the inner shaft 10 and the arc surface 54 of the corresponding resin rod 41, 42, 43. Thereby, the escape place of the meat | flesh of the said resin rod 41, 42, 43 when the corresponding resin rod 41, 42, 43 elastically deforms is ensured. Therefore, when the resin rods 41, 42, 43 are elastically deformed, the meat between the shafts 10, 11 comes into contact with portions of the inner shaft 10 other than the first and second slopes 71, 72. Can be prevented from inadvertently changing the transfer characteristics.

  Further, the gap in the circumferential direction C between the inner shaft 10 and the outer shaft 11 can be filled with resin rods 41, 42, 43. Thus, even when the steering angle θ is −θ1 ≦ θ ≦ θ1 (when the relative phase between the inner shaft 10 and the outer shaft 11 is within a predetermined range), both shafts through the resin rods 41, 42, and 43 are used. The rigidity of connection in the circumferential direction C of 10 and 11 can be increased. Thereby, the both shafts 10 and 11 can be rotated together without causing a rotation transmission delay between the both shafts 10 and 11. Therefore, it is possible to secure a feeling of rigidity in the connection between the inner shaft 10 and the outer shaft 11 in the circumferential direction C, and to achieve a good steering feeling.

One end of each resin rod 41, 42, 43 is fixed to the connecting portion 44. Thereby, it can prevent more reliably that each resin rod 41,42,43 is twisted with respect to a corresponding pair of axial groove | channels 31,32; 33,34; 35,36. As a result, a reduction in steering feeling can be prevented more reliably.
Even when the steering angle θ is −θ1 ≦ θ ≦ θ1, the steering shaft 2 is steered by connecting the inner shaft 10 and the outer shaft 11 in the circumferential direction C by the resin rods 41, 42, 43. A reaction force torque as a reaction equal to the input torque corresponding to the steering angle θ can be generated. As a result, insufficient steering or excessive steering can be prevented, and the driver's steering wobbling can be prevented.

  Further, since the steering reaction force is generated to some extent before the steering angle θ becomes θ <−θ1 or θ1 <θ, the transmission torque before and after the steering angle θ becomes θ <−θ1 or θ1 <θ. Can be prevented, and the reaction force torque as a reaction equal to the input torque can be smoothly increased. Therefore, it is possible to convey only information necessary for the driver such as road surface condition and vehicle behavior without giving unnecessary torque fluctuation to the driver. As a result, there is no steering wobbling near the steering neutral where the steering angle θ is zero, and the stability of the steering device 1 obtained from the steering member 2 can be improved.

  Further, when the steering member 2 is suddenly steered from the steering neutral state, the resin rods 41, 42, 43 between the inner shaft 10 and the outer shaft 11 are compressed, and the male serration 27 of the inner shaft 10 and the female of the outer shaft 11 are compressed. The serrations 29 come into contact with each other. At this time, each resin rod 41, 42, 43 exhibits a buffering action. Thereby, the meshing sound by the rigid contact of each serration 27 and 29 can be suppressed.

As described above, the vehicle steering device 1 excellent in steering feeling, durability, and quietness can be realized.
The present invention is not limited to the contents of the above-described embodiment, and various modifications can be made within the scope of the claims.
For example, the groove 50 of each resin rod 41, 42, 43 may be opened inward in the radial direction R. Further, the contact area with the outer shaft 11 may be further reduced by notching the middle portion in the longitudinal direction L of the arc surface 54 of each resin rod 41, 42, 43 larger. Thereby, the contact area of each resin rod 41, 42, 43 and the outer shaft 11 can be reduced. As a result, sliding resistance when the inner shaft 10 and the outer shaft 11 slide relative to each other can be further reduced, and telescopic adjustment can be performed smoothly with less force. Moreover, the sliding resistance between the shafts 10 and 11 can be set to a desired value by appropriately setting the length of the notches.

Further, the resin body 39 may be fixed to the outer shaft 11.
Further, in each of the above embodiments, a single resin rod that is not connected to the connecting portion may be used.
Moreover, it may replace with the serration 25 and may provide a spline. In this case, the male spline of the spline is formed on the outer peripheral surface 26 of the inner shaft 10, and the female spline is formed on the inner peripheral surface 28 of the outer shaft 11.

Further, four or more pairs of axial grooves facing each other between the inner shaft 10 and the outer shaft 11 may be provided.
Furthermore, the present invention can be applied to a power steering device such as an electric power steering device that applies a steering assist force to a steering shaft with an electric motor, or a hydraulic power steering device that applies a steering assist force to a rack shaft with a hydraulic cylinder. it can.
In this case, the absolute value of the steering angle θ at which the application of the steering assist force is started is set so as to correspond to the predetermined steering angle θ1. That is, the region where the steering angle θ is −θ1 ≦ θ ≦ θ1 is a so-called dead zone where no steering assist force is generated regardless of the steering of the steering member 2. Torque is transmitted between the inner shaft 10 and the outer shaft 11 through each resin rod at a minute steering angle (dead zone) where the steering assist force is not applied.

  Further, the present invention may be applied to other vehicle steering steering shafts such as an intermediate shaft disposed between the steering member and the steering mechanism.

It is a mimetic diagram showing a schematic structure of a steering device for vehicles provided with a telescopic shaft for vehicle steering concerning one embodiment of the present invention. It is a disassembled perspective view of the principal part of a steering shaft. It is sectional drawing of the principal part of a steering shaft. It is sectional drawing which follows the IV-IV line of FIG. It is an enlarged view of the principal part of FIG. It is sectional drawing of the principal part which shows the state which the torque is acting between the inner shaft and the outer shaft. It is a schematic diagram of the principal part when it fits so that both shafts may be bent halfway. It is a side view of the principal part which shows the state in which the inner shaft and the outer shaft were arranged straight. It is a graph which shows the relationship between a steering angle and the torque which arises in a steering member when a steering member is reciprocatingly rotated by lock to lock comparatively quickly. It is a graph which shows the relationship between the steering angle and the torque which arises in a steering member in a comparative example. It is a graph which shows the relationship between a steering angle and the torque (torsion of a steering shaft) which arises in a steering member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle steering device, 2 ... Steering member, 3 ... Steering shaft (vehicle telescopic shaft), 10 ... Inner shaft, 11 ... Outer shaft, 25 ... Serration (rigid connecting element), 26 ... (inner shaft) Outer peripheral surface, 27 ... male serration (male teeth), 28 ... inner peripheral surface, 29 ... female serration (female teeth), 31, 32, 33, 34, 35, 36 ... axial grooves, 41, 42, 43 ... resin rod, 50 ... groove, 81 ... first contact point, 82 ... second contact point, 83 ... third contact point, 84 ... fourth contact point, C ... circumferential direction, D ... Pitch circle, E1 ... first line (line connecting the first and fourth contact points), E2 ... second line (line connecting the second and third contact points), F ... intersection, H1 ... first 1 contact angle, H2 ... second contact angle, H3 ... third contact angle, H4 ... fourth contact angle, S ... axial direction.

Claims (4)

In the vehicle steering telescopic shaft that rotates according to the steering of the steering member,
An inner shaft and a cylindrical outer shaft fitted together so as to be slidable relative to each other in the axial direction and capable of transmitting torque to each other;
Including a plurality of male teeth formed on the outer peripheral surface of the inner shaft and a plurality of female teeth formed on the inner peripheral surface of the outer shaft, and when the relative phase of both shafts exceeds a predetermined range A rigid coupling element that rigidly couples both shafts circumferentially by meshing with teeth;
At least three pairs of axial grooves formed on each of the outer peripheral surface of the inner shaft and the inner peripheral surface of the outer shaft and facing each other;
Each of the pair of axial grooves is interposed in a four-point contact state, and when the relative phase of the inner shaft and the outer shaft is within a predetermined range, one of the two shafts is floated in the circumferential direction with respect to the other. anda tree Aburabo as a plurality of elastic connecting elements to support,
When viewed along the axial direction of the inner shaft, each of the resin rods contacts the axial groove of the inner shaft at two points at the first and second contact points, and against the axial groove of the outer shaft. 2 points contact at the 3rd and 4th contact points,
When viewed along the axial direction of the inner shaft, the intersection of the line connecting the first and fourth contact points and the line connecting the second and third contact points is the male and female teeth. A telescopic shaft for steering a vehicle, characterized in that the telescopic shaft is arranged on a pitch circle of the mesh.   2. A telescopic shaft for steering a vehicle according to claim 1, wherein each of the resin rods has a U-shaped cross section and includes a groove opened in one radial direction of the inner shaft.   3. The contact angle between the axial groove of the inner shaft at the first contact point and the resin rod as viewed along the axial direction of the inner shaft is the outer shaft at the fourth contact point according to claim 1. The contact angle between the axial groove of the inner shaft and the resin rod is equal to the contact angle between the axial groove of the inner shaft and the resin rod at the second contact point, and the outer shaft at the third contact point. A telescopic shaft for steering a vehicle, characterized by being equal to a contact angle between the axial groove and the resin rod.   A vehicle steering apparatus comprising the vehicle steering telescopic shaft according to any one of claims 1 to 3, which rotates according to steering of a steering member.

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