JP5403015B2 - Outer column for telescopic steering device - Google Patents

Description

  The present invention relates to an improvement in an outer column that constitutes a telescopic steering device for adjusting the front-rear position of a steering wheel. Specifically, for example, even when an excessive twisting force is applied to the outer column, such as when the steering wheel is operated with a large force while the steering lock device is activated, It is intended to realize a structure in which damage such as cracks is unlikely to occur.

  For example, as described in Patent Document 1, the automobile steering device is configured as shown in FIG. 7, and the rotation of the steering wheel 1 is transmitted to the input shaft 3 of the steering gear unit 2. The pair of left and right tie rods 4 and 4 are pushed and pulled with the rotation of 3 to give a steering angle to the front wheels. The steering wheel 1 is supported and fixed at the rear end portion of the steering shaft 5, and the steering shaft 5 is rotatably supported by the steering column 6 with the cylindrical steering column 6 inserted in the axial direction. Has been. The front end portion of the steering shaft 5 is connected to the rear end portion of the intermediate shaft 8 via a universal joint 7a, and the front end portion of the intermediate shaft 8 is connected to the input shaft 3 via another universal joint 7b. Connected to.

  With such a steering device, a telescopic mechanism for adjusting the front-rear position of the steering wheel 1 according to the driver's physique and driving posture has been widely known. In order to configure such a telescopic mechanism, the steering column 6 has a structure in which an outer column 9 and an inner column 10 are telescopically combined, and the steering shaft 5 includes an outer tube 11 and an inner shaft. 12 is configured to be capable of transmitting torque and expanding and contracting by spline engagement or the like. The illustrated example also incorporates a tilt mechanism that can adjust the vertical position of the steering wheel 1. Furthermore, an electric power steering device is also incorporated, which reduces the force required to operate the steering wheel 1 using the electric motor 13 as an auxiliary power source. For this purpose, a housing 14 housing a worm reduction gear constituting the electric power steering device is coupled and fixed to the front end of the steering column 5, and the housing 14 is attached to the vehicle body 15 with a horizontal shaft 16. It supports a pivoting displacement centered on it. Further, a displacement bracket 18 fixed to a part of the steering column 6 is supported with respect to a support bracket 17 supported at a different position of the vehicle body 15 so as to be capable of displacement in the front-rear direction and the vertical direction.

  In the case of a tilt mechanism or a telescopic mechanism, it is necessary to make the position of the steering wheel 1 adjustable or to be held at the adjusted position based on the operation of the adjustment lever, except for an electric mechanism. . An example of a specific structure of such a position adjusting mechanism will be described with reference to FIGS. The steering column 6a can be telescopically expanded and contracted by fitting the rear end portion of the front inner column 10a into the front end portion of the rear outer column 9a. The housing 14a fixed to the front end of the inner column 10a is supported with respect to the vehicle body 15a so as to be able to swing and swing around the horizontal axis 16a. The outer column 9a is formed by die-casting a light alloy such as an aluminum alloy or a magnesium alloy, and the inner diameter of the front end portion can be elastically expanded or reduced. The shape of the outer column 9a is slightly different from that shown in FIGS. 8 to 9 and that shown in FIGS. 10 to 11 but is basically the same.

  In order to be able to elastically expand and contract the inner diameter of the front end portion of the outer column 9a, an axial slit 19 that is long in the axial direction is provided at the front end portion or an intermediate portion, and an intermediate portion of the axial slit 19 in the outer peripheral surface. A pair of sandwiched portions 20 and 20 are formed at positions where the portion is sandwiched from both sides in the width direction. The shape of the rear end portion (the right end portion in FIGS. 8 and 10 to 11) of the axial slit 19 is a semicircular arc shape having a constant curvature radius, as shown in detail in FIG. Further, a circumferential slit 21 is formed in the lower half of the front end portion of the outer column 9a, and the front end portion (left end portion in FIG. 10) of the axial slit 19 is formed in the circumferential intermediate portion of the circumferential slit 21. Open. A structure in which the front end portion of the axial slit is opened to the front end surface of the outer column without providing such a circumferential slit 21 is also known. In addition, the rear end of both the sandwiched portions 20, 20 at the rear end portion of the axial slit 19 on the outer peripheral surface of the intermediate portion of the outer column 9 a located at the rear portion of the sandwiched portions 20, 20. Reinforcing wall portions 22 are provided so as to surround a portion protruding rearward from the portion. The inner peripheral side wall surface of the reinforcing wall 22 and the inner peripheral surface of the axial slit 19 are continuous without a step. Further, the height of the reinforcing wall 22 (the vertical dimension in FIG. 10A and FIG. 11B) is, as will be described in detail in FIG. The latter half portion {the right side portion of FIG. 11B) surrounding the end portion is higher than the front half portion {the left side portion of FIG. 11B}, and has a thickness {FIG. 10B and FIG. 11 (A) vertical dimension}, as shown in detail in FIG. 11 (A), the middle part in the front-rear direction of the latter half is thicker than the other parts, and the part is made thicker 31. , 31. The thickness of the portion of the reinforcing wall 22 that is separated from both the thick portions 31, 31 is made smaller than both the thick portions 31, 31, so that the inner diameter of the front end portion of the outer column 9a is elastic. To reduce the force required to shrink. Further, longitudinally elongated holes 23 and 23, which are long in the axial direction of the outer column 9a, are formed in the portions of the sandwiched portions 21 and 21 that are aligned with each other (for example, FIG. 4 of Patent Document 1). reference).

  On the other hand, each of the pair of left and right support plate portions 24, 24 constituting the support bracket 17a supported by another portion of the vehicle body 15a is aligned with each other in a partial arc shape with the horizontal axis 16a as the center. The direction long holes 25 and 25 are formed. Then, the adjusting rod 26 is inserted into both the vertical holes 25 and 25 and the longitudinal holes 23 and 23. In the illustrated example, the adjusting rod 26 is a bolt, and a head 27 provided at the base end (the right end in FIG. 9) is inserted into one (right side in FIG. 9) one of the vertically elongated slots 25. Only the displacement in the length direction of the vertical direction long hole 25 is engaged. On the other hand, the base end portion of the adjustment lever 29 is coupled and fixed to the nut 28 screwed into the distal end portion of the adjustment rod 26, and the inner surfaces of the nut 28 and the head portion 27 are connected by operating the adjustment lever 29. The interval can be adjusted.

  When adjusting the position of the steering wheel 1, the adjusting lever 29 is oscillated and displaced in a predetermined direction (generally downward) to widen the space between the inner surfaces of the nut 28 and the head 27. . In this state, the surface pressure of the abutting portion between the inner side surfaces of the both support plate portions 24 and 24 and the outer side surfaces of the both sandwiched portions 20 and 20 is reduced or lost. At the same time, the inner diameter of the front end portion of the outer column 9a is elastically expanded, and the surface pressure of the contact portion between the inner peripheral surface of the front end portion of the outer column 9a and the outer peripheral surface of the rear end portion of the inner column 10a is reduced or lost. To do. In this state, the front / rear position and the vertical position of the steering wheel 1 can be adjusted within a range in which the adjustment rod 26 can be displaced inside the front / rear direction long holes 23, 23 and the upper / lower direction long holes 25, 25. Then, in a state where the steering wheel 1 is moved to a desired position, the adjustment lever 29 is oscillated and displaced in a direction opposite to the predetermined direction, so that the inner side surfaces of the nut 28 and the head portion 27 are aligned with each other. If the interval is shortened, the steering wheel 1 can be held at the adjusted position.

  The configuration and operation of the position adjustment device for the steering wheel 1 are as described above. However, in addition to such a position adjustment device, when the anti-theft steering lock device is incorporated, the durability of the outer column 9a is ensured. There is room for improvement. This steering lock device is constructed by mounting a key lock cylinder in a mounting hole 30 formed in a part of the outer column 9a and a key lock collar in a part of the steering shaft 5a. When the ignition switch is removed, the key lock pin provided in the key lock cylinder engages with the key lock hole provided in the key lock collar, and the steering shaft 5a rotates relative to the outer column 9a. Be blocked.

When trying to forcibly rotate the steering wheel 1 in a state where such a steering lock device is operated, the steering shaft 5a is connected to the outer column 9a via the key lock collar and the key lock pin. A large torque is applied. Based on this torque, stress is generated at the rear end portion of the axial slit 19. In the case of the conventional structure, the rear end portion of the axial slit 19 has a semicircular arc shape with a small radius of curvature as shown in FIG. easy. That is, the twisting force applied to the outer column 9a is applied to the portion between the rear end portion of the axial slit 19 and the thick portions 31, 31 formed near the rear end portion of the reinforcing wall portion 22. concentrate. In the case of the conventional structure shown in FIGS. 10 to 11, the axial distance L ₀ between this portion is short, and the absolute value of the stress generated in this portion (maximum value of stress generated in each portion of this portion) tends to be large. If this stress becomes excessive, there is a possibility that a crack starting from the rear end portion of the axial slit 19 may be generated in a part (maximum value generation site) of the outer column 9a. The situation in which the steering wheel 1 is forcibly rotated while the steering lock device is activated is an abnormal situation in which an automobile is being stolen. Even in such a situation, the outer column 9a may be cracked. It is not preferable that damage occurs.

In order to prevent the outer column from cracking due to such a reason, as shown in FIG. 12, a wide portion 32 is provided at the rear end portion (right end portion in FIG. 12) of the axial slit 19a. It is conceivable to increase the radius of curvature of the partial arc portion existing at the rear end portion of the direction slit 19a. By the amount to increase the curvature radius of the partial arc portion, the length L ₁ of the easy part elastically deformed by twisting direction of the force applied to the outer column 9b is increased, and suppressing the absolute value of the stress generated, cracks It can be difficult to cause damage. However, even with the improved structure shown in FIG. 12, although the absolute value of stress can be suppressed lower than that of the conventional structure shown in FIGS. 10 to 11, there is still room for improvement in order to reduce the absolute value.

JP 2010-254234 A

  In view of the above-described circumstances, the present invention suppresses the stress generated in a part of the outer column sufficiently low even when a large force is applied to the outer column in the twist direction, and the outer column is cracked. The invention was invented to realize a structure in which the damage is unlikely to occur.

The outer column for a telescopic steering device according to the present invention is entirely made of a metal material such as a light alloy such as an aluminum alloy or a magnesium alloy, and is made cylindrical.
Then, an axial slit that is long in the axial direction is formed near one end with respect to the axial direction, and a pair of sandwiched portions are formed at positions on the outer peripheral surface that sandwich at least a part of the axial slit from both sides. Accordingly, the inner diameter of the portion closer to the one end can be elastically expanded / contracted based on the increase / decrease of the load for clamping both the sandwiched portions from both sides in the width direction.

  In particular, in the outer column for a telescopic steering device according to the present invention, the end closer to the other end in the axial direction of the axial slit is a wide portion. Further, the width dimension of the wide portion is largest at the intermediate portion with respect to the axial direction, and is made smaller at the portion closer to the other end than the intermediate portion as the distance from the intermediate portion increases. Further, the curvature of the both side edges in the width direction closer to the other end than the intermediate portion is related to the shape viewed from the radial direction (as in the structure of the prior invention shown in FIG. 12), and the portion is a semicircular arc having a constant curvature. Therefore, it is smaller than the curvature when it is assumed to be continuous by a straight line (closer to a straight line or a straight line than a single arc having a constant curvature radius).

When carrying out the present invention as described above, for example, as in the invention described in claim 2, the shape of the portion closer to the other end than the middle portion of the wide portion in the axial slit is changed to both sides in the width direction. A V-shape having a curved tip end portion, which is composed of a linear portion of the edge and an arc portion that smoothly connects the other ends of both the linear portions.
Alternatively, as in the invention described in claim 3, the shape of the wide portion in the axial slit is an ellipse having a major axis in the axial direction and a minor axis in the circumferential direction.

  Further, when the present invention is carried out, preferably, as in the invention described in claim 4, along the portion of the axial slit that protrudes toward the other end portion in the axial direction with respect to the both sandwiched portions. A protruding wall is formed on the outer peripheral surface portion. And the height dimension of the part located in the other end of the said wide part is made lower than the height dimension of the remaining part among this protrusion wall regarding an axial direction.

According to the outer column for a telescopic steering device of the present invention configured as described above, even when a large force is applied in the twisting direction, the stress generated in a part of the outer column is suppressed to a sufficiently low level. Damage such as cracks can hardly occur in the column.
That is, in the case of the present invention, the end closer to the other end in the axial direction of the axial slit is a wide portion whose width dimension decreases toward the other end in the axial direction, and the width near the other end of the wide portion. Since the curvature of both side edges in the direction is reduced (the radius of curvature is increased), the length dimension of the portion that is elastically deformed by the force in the twisting direction can be increased. For this reason, the absolute value of the stress generated in each portion can be kept low, and the occurrence of the damage can be prevented.

The side view (A) and bottom view (B) of an outer column which show the 1st example of embodiment of this invention. FIG. 2B is an enlarged view (A) of FIG. 1 and a cross-sectional view (B) of (A). FIGS. 2A and 2B are sectional views (B) and (B) of FIG. 2 (C), which are similar to FIG. 2 (A), showing a second example of the embodiment of the present invention. ). The 3rd example of embodiment of this invention, The figure (A) similar to (A) of FIG. 2, and the ho-ho sectional drawing (B) of (A). FIG. 6A is a cross-sectional view (B) of FIG. 2 (A) similar to FIG. 2 (A), showing a fourth example of the embodiment of the present invention. The 5th example of embodiment of the present invention, the figure (A) similar to (A) of Drawing 2, and the tote sectional view (B) of (A). The partial cutting schematic side view which shows the 1st example of the steering device provided with the telescopic mechanism conventionally known. The side view which shows the 2nd example. FIG. 9 is an enlarged cross-sectional view of FIG. 8. The side view (A) and bottom view (B) of the outer column conventionally known. Similarly, a section enlarged view (A) and a sectional view (B) of (A) in FIG. FIG. 12 is a view similar to FIG. 11A, showing an example of an improved structure that was considered prior to the present invention.

[First example of embodiment]
1 and 2 show a first example of an embodiment of the present invention corresponding to claims 1 and 2. The outer column for the telescopic steering device of this example is characterized by the absolute stress generated at the rear end (the right end in FIGS. 1 and 2) of the axial slit 19b even when a large force is applied in the twisting direction. In order to keep the value (maximum value) low, the shape of the rear end of the axial slit 19b is devised. Since the structure and operation of the other parts are the same as those of the conventional structure shown in FIGS. 8 to 11 described above, description of the equivalent parts will be omitted or simplified, and the following description will focus on the characteristic parts of this example.

  In the outer column 9c of this example, the rear end portion (the right end portion in FIGS. 1 and 2) of the axial slit 19b is a wide portion 32a. The wide portion 32a is substantially diamond-shaped when viewed from the radial direction of the outer column 9c, and the width dimension is greatest at the intermediate portion in the axial direction. And it becomes smaller as it leaves | separates from this intermediate part (as it goes to the front-back direction) in a part near a rear end and a part near a front end rather than this intermediate part. Among these, the shape of the portion closer to the rear end than the intermediate portion is formed by linear portions 33 and 33 (curvature = 0) on both side edges in the width direction, and arc portions that smoothly connect the rear ends of both the straight portions 33 and 33. 34 (curvature = 1 / r) having a curved V-shaped tip. The position of the arc portion 34 in the axial direction of the outer column 9c is the same as the position of the arc portion 34a existing at the rear end portion of the axial slit 19 in the conventional structure shown in FIGS. It is said. Further, in the case of this example, with respect to the front half of the wide portion 32a, the shape of the left and right side edges viewed from the radial direction is a straight line, and both the front and rear ends are adjacent to each other in the axial direction, It continues smoothly through the arcuate curved surface. Further, of the reinforcing wall 22a formed in the portion surrounding the wide portion 32a, the thickness of the portion along the straight portions 33, 33 {the vertical dimension in FIGS. 1B and 2A. } Has a wedge-like shape as it gradually increases from the rear end portion toward the front end portion, as viewed from the radial direction of the reinforcing wall portion 22a.

Note that the angle θ of both straight portions 33, 33 to each other do, smaller, in order to increase the axial distance L ₂ to the rear end of said axial slit 19b from the maximum width W portion of the wide portion 32a However, if it is made too small, the axial length of the axial slit 19b becomes longer. In contrast, when too large the angle theta, it is difficult to secure the axial distance L _2. Considering these matters, the angle θ is preferably about 10 to 70 degrees, more preferably about 20 to 60 degrees. Further, the curvature radius r of the circular arc portion 34 is smaller, the shaft is preferred in order to increase the direction distance L _2, if too small, it tends to concentrate stress in the arcuate portion 34, the arcuate portion 34 Damage, such as cracks, starting from is likely to occur. In contrast, when too large the curvature radius r, as shown in FIG. 12 described above, is close to the structure considered earlier, is difficult to secure the axial distance L _2. Considering these matters, the radius of curvature r is ½ or more of the width w of the axial slit 19b that is out of the wide portion 32a, and is 1 of the maximum width W of the wide portion 32a. Less than / 2 (w / 2 ≦ r <W / 2), more preferably r = w / 2. Moreover, the shape of the maximum width W part of the said wide part 32a is made into the partial cylindrical surface shape whose curvature radius is R. As shown in FIG. The radius of curvature R of the maximum width W portion is larger than the radius of curvature r of the arc portion 34 (R> r), preferably R = W / 2. Further, the inner side surfaces of the pair of sandwiched portions 20, 20 facing each other have a stepped shape in which the distal end side is a thin portion, and the interval between the inner side surfaces of the distal end side portion is D. Then, the maximum width W and the radius of curvature R of the maximum width W portion are restricted to a range of 2R ≦ W ≦ D in relation to the distance D.

According to the structure of the present example configured as described above, even when a large force is applied to the outer column 9c in the twisting direction, the stress generated in a part of the outer column 9c is suppressed to a sufficiently low level. The outer column 9c can be hardly damaged such as cracks.
That is, in a state where the outer column 9c is incorporated in the steering device and the position of the steering wheel 1 (see FIGS. 7 to 8) is maintained, the outer column 9c is provided on both sides of the axial slit 19b at the front portion of the steering column 9c. In addition, the pair of sandwiched portions 20 and 20 are strongly clamped by the pair of left and right support plate portions 24 and 24 (see FIG. 9) constituting the support bracket 17a. In this state, if the steering wheel 1 is to be rotated strongly while operating the steering lock device installed in the mounting hole 30 portion of the steering column 9c, a large twisting force is applied to the outer column 9c. .

  Of the outer column 9c, the portion where the both sandwiched portions 20, 20 are sandwiched by the two support plate portions 24, 24 is provided with these thick sandwiched portions 20, 20. In addition, the amount of elastic deformation is limited by being sandwiched between the support plate portions 24, 24. In addition, since the latter half portion existing behind the rear end of the axial slit 19b (the portion where the wide portion 32a is formed) is a continuous cylinder over the entire circumference, the amount of elastic deformation is still limited. It is done. The portion that elastically deforms is mainly a portion near the rear end of the axial slit 19b that exists behind the both sandwiched portions 20 and 20. This rear end portion is necessary to secure the expansion / contraction amount of the inner diameter of the outer column 9c, but becomes a portion that is concentrated and elastically deformed when the force in the large twisting direction is applied. Based on the elastic deformation in such a direction, the amount of elastic deformation at the rear end of the axial slit 19b increases, and a large stress tends to be generated at the rear end.

  In the case of the outer column 9c of this example, the wide portion 32a having a substantially rhombic shape elongated in the axial direction is formed at the rear end portion of the axial slit 19b, so that it is elastically deformed by the force in the twisting direction. The length dimension of the part to be made can be increased. That is, by this force, both sides in the width direction of the outer column 9c at the rear end portion of the axial slit 19b located behind the both sandwiched portions 20, 20 are relatively displaced with respect to the axial direction. When it becomes a tendency, the reinforcement wall part 22a formed in the part surrounding the wide part 32a tends to be elastically deformed. Among the reinforcing wall portions 22a, the front portion of the maximum width W portion is continuous with both the sandwiched portions 20 and 20 while increasing the thickness dimension rapidly toward the front, so that it is relatively rigid. And the amount of elastic deformation of the front side portion is limited. Therefore, elastic deformation by the force in the twisting direction is mainly in the rear portion of the maximum width W portion.

In the case of the outer column 9c of this example, as described above, the shape of the portion closer to the rear end than the intermediate portion is V-shaped, so that from the maximum width W portion to the rear end portion of the axial slit 19b. of the axial distance L _2, of course, the axial distance L ₀ between the portion of the conventional structure shown in FIG. 10-11 described above, the easy part is elastically deformed in the previous invention the structure shown in FIG. 12 of the aforementioned It can be sufficiently larger than the length L ₁ (L ₂ > L ₁ > L ₀ ). Moreover, even when the large axial distance L ₂ from the maximum width W portion to the rear end of said axial slit 19b, the position of the rear end portion of the arcuate portion 34, shown in FIG. 12 described above, It can be made the same as the position of the rear end portion of the arc portion 34a in the structure considered above. By adopting such a configuration, even when the total sum of the elastic deformation amounts of a part of the outer column 9c (integral value of the elastic deformation amounts of the respective minute portions) based on the force in the twisting direction is the same, The amount of elastic deformation of the portion can be kept low. As a result, the absolute value of the stress generated in each minute portion that is elastically deformed can be kept low, and damage such as cracks can be prevented from occurring in the outer column 9c. Further, the shape of the reinforcing wall 22a as viewed from the radial direction of the portion along the straight portions 33, 33 is also wedge-shaped, which is advantageous in terms of suppressing the absolute value of stress (maximum stress). . That is, among the portions along both the straight portions 33, 33, the reinforcing wall 22a is thicker toward the front portion where a large force is easily applied based on the force in the twisting direction. The generated stress can be further reduced. Further, since the thickness of the reinforcing wall 22a is increased at the front portion, when the outer column 9c and the mold are separated from each other during die casting of the outer column 9c, the front wall This is advantageous from the standpoint of reducing the cost by improving the yield by making it difficult to damage the side portion. Since the axial distance L ₂ from the maximum width W portion to the rear end of said axial slit 19b is preferably larger in order to secure the axial distance L _2, the maximum width W of the wide portion 32a The portion may be positioned in front of the rear end surface 36 of the pair of sandwiched portions 20 and 20 formed on the lower surface of the outer column 9c with the axial slit 19b interposed therebetween.

[Second Example of Embodiment]
FIG. 3 shows a second example of an embodiment of the present invention corresponding to claims 1, 2, and 4. In the case of the outer column 9d of this example, a notch 35 is provided at the rear end of the reinforcing wall portion 22b formed at a position surrounding the wide portion 32a provided at the rear end of the axial slit 19b. The rigidity of the reinforcing wall portion 22b in the circumferential direction of the column 9d is kept low. That is, in the reinforcing wall 22b, the cutout portion 35 is provided in a portion corresponding to the arc portion 34 of the wide portion 32a, and the reinforcing wall 22b is lowered at this portion, and the circumferential direction of the outer column 9d is related. The rigidity of the reinforcing wall 22b is kept low. In order to suppress the absolute value of the stress generated in the reinforcing wall 22b portion based on the twisting force applied to the outer column 9d, the height of the reinforcing wall 22b (the protrusion from the outer peripheral surface of the outer column 9d) is reduced. It is effective to secure (large) or increase the thickness. However, when the reinforcing wall 22b is simply raised or thickened, the rigidity of the rear end portion of the axial slit 19b in the circumferential direction of the outer column 9d becomes too high, and the steering wheel 1 (FIGS. 7 and 8). There is a possibility that the force required to reduce the inner diameter of the front end portion of the steering column 9d is increased in order to keep the front / rear position of the reference) at the adjusted position. Therefore, in the case of this example, by forming the notch 35, the rigidity in the circumferential direction of the rear end portion of the axial slit 19b is appropriately reduced, and the inner diameter of the front end portion of the steering column 9d is reduced. The increase in force required to shrink the is suppressed. The continuous portion between the bottom surface and the side surface (the rear end surface of the reinforcing wall 22b) of the notch 35 is a curved surface having a large radius of curvature to prevent stress concentration on the continuous portion. Since the configuration and operation of other parts are the same as those of the first example of the above-described embodiment, illustration and description regarding the equivalent parts are omitted.

[Third example of embodiment]
FIG. 4 shows a third example of the embodiment of the present invention corresponding to claims 1 and 2. In the case of this example, the radius of curvature r ′ of the arc portion 34b constituting the rear end portion of the wide portion 32b provided at the rear end portion of the axial slit 19c is greater than that of the first example of the embodiment described above. Accordingly, the inclination angle θ ′ of the pair of left and right straight portions 33a and 33a is reduced accordingly. Furthermore, the thickness of the front half of the reinforcing wall portion 22c provided so as to surround the wide portion 32b is made thicker than in the first example of the embodiment. Such a structure of this example is employed when the wide portion 32b can be enlarged in relation to other components of the steering device. By increasing the radius of curvature r ′ of the arc portion 34b, the stress generated in this portion can be further relaxed. Further, by further increasing the thickness of the first half of the reinforcing wall portion 22c, the stress generated in the first half can be further alleviated. Since the configuration and operation of other parts are the same as those of the first example of the above-described embodiment, illustration and description regarding the equivalent parts are omitted.

[Fourth Example of Embodiment]
FIG. 5 shows a fourth example of an embodiment of the present invention corresponding to claims 1 and 2. In the case of this example, the shape of the front half of the wide portion 32c provided at the rear end of the axial slit 19d is an arc. And this arc-shaped front half part and the largest width part of this wide part 32c and the front part rather than the said rear-end part are continuously made continuous among the said axial direction slits 19d. Since the configuration and operation of other parts are the same as those of the first example of the above-described embodiment, illustration and description regarding the equivalent parts are omitted.

[Fifth Example of Embodiment]
FIG. 6 shows a fifth example of an embodiment of the present invention corresponding to claims 1 and 3. In the case of this example, the shape of the wide portion 32d provided at the rear end portion of the axial slit 19e is an ellipse whose major axis is the axial direction and whose minor axis is the circumferential direction. In this way, even when the shape of the wide portion 32d is an ellipse that is long in the axial direction, the length of the elastically deformable portion is increased based on the force applied in the twisting direction to prevent damage such as cracks. I can plan. In this case, increasing the curvature radius of the rear end portion of the wide portion 32d is advantageous in terms of suppressing the absolute value of the stress generated at the rear end portion. Since the configuration and operation of other parts are the same as those of the first example of the above-described embodiment, illustration and description regarding the equivalent parts are omitted.

When the present invention is implemented, the positional relationship in the vertical direction can be reversed from the case of each example of the illustrated embodiment. That is, the present invention can be implemented with a structure in which a pair of sandwiched portions are provided on the upper surface side of the outer column and the adjustment rod is disposed above the outer column.
Also, the positional relationship in the front-rear direction can be reversed from that in the above examples. That is, each of these examples describes an outer column that constitutes a steering column whose length can be expanded and contracted by fitting the rear end of the inner column at the front end thereof, but the inner column at the rear end. You may comprise so that the front-end part may be fitted inside. In this case, the wide portion is provided at the front end of the axial slit.

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering gear unit 3 Input shaft 4 Tie rod 5, 5a Steering shaft 6, 6a Steering column 7a, 7b Universal joint 8 Intermediate shaft 9, 9a, 9b, 9c, 9d Outer column 10 Inner column 11 Outer tube 12 Inner shaft DESCRIPTION OF SYMBOLS 13 Electric motor 14, 14a Housing 15, 15a Car body 16, 16a Horizontal shaft 17, 17a Support bracket 18 Displacement bracket 19, 19a, 19b, 19c, 19d, 19e Axial slit 20 Clamping part 21 Circumferential slit 22, 22a, 22b, 22c Reinforcing wall part 23 Longitudinal direction long hole 24 Support plate part 25 Vertical direction long hole 26 Adjusting rod 27 Head 28 Nut 29 Adjusting lever 30 Mounting hole 31 Thick part 32, 32a, 32b, 32c, 32 Wide portions 33,33a straight portions 34, 34a, 34b arc portion 35 notched portion 36 the rear end surface

Claims (4)

  The whole is made of a metal material in the shape of a cylinder, and a pair of axial slits are formed in a portion near one end in the axial direction, and a pair of axial slits on the outer peripheral surface is sandwiched from both sides. An outer column for a telescopic steering device in which the inner diameter of the portion closer to the one end can be elastically expanded / contracted by forming the to-be-clamped portions, respectively, based on the amount of load that clamps both the to-be-clamped portions from both sides in the width direction. In the axial slit, the end closer to the other end in the axial direction is the widened portion, and the width dimension of the widened portion is the largest in the intermediate portion in the axial direction, and closer to the other end than the intermediate portion. A portion is made smaller as it is farther from the intermediate portion, and the curvature of the both sides in the width direction closer to the other end than the intermediate portion is related to the shape viewed from the radial direction. Telescopic steering apparatus for outer column, characterized in that is smaller than the curvature assuming that was continuous with the semi-circular arc.   Among the axial slits, the shape of the portion closer to the other end than the intermediate portion of the wide portion is composed of a straight portion at both side edges in the width direction and an arc portion that smoothly connects the other ends of both the straight portions. 2. The outer column for a telescopic steering device according to claim 1, wherein the outer column is a V-shape with a curved tip.   2. The outer column for a telescopic steering device according to claim 1, wherein a shape of the wide portion of the axial slit is an ellipse having a major axis in the axial direction and a minor axis in the circumferential direction.   A protruding wall is formed on an outer peripheral surface portion along a portion of the axial slit that protrudes toward the other end portion with respect to the axial direction than the both sandwiched portions. The outer column for a telescopic steering device according to any one of claims 1 to 3, wherein a height dimension of a portion located at the other end of the wide portion is lower than a height dimension of an intermediate portion in the axial direction.

Images