JP2005349964A - Telescopic shaft for vehicle steering - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a stable sliding load and prevent rattling in the direction of rotation, thereby making it possible to apply a preload with many degrees of design freedom from high to low rigidity for improved assembling properties. <P>SOLUTION: A cylindrical outer ring 20 is provided on the outer periphery of a female shaft 2. A plurality of elastic bodies 30 is interposed between the outer ring 20 and the female shaft 2. The elastic bodies 30 can thus apply the preload to a spherical body 7 and an axial protrusion 4 via the female shaft 2. That is, the female shaft 2 is deflected radially inward by a slot 2a during preloading and can thereby elastically press the spherical body 7 and the axial protrusion 4 against a male shaft 1 under the biasing force of the elastic bodies 30. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a telescopic shaft for vehicle steering that is incorporated in a steering shaft of a vehicle and has a male shaft and a female shaft that are non-rotatable and slidably fitted to each other.

  Conventionally, the steering mechanism part of an automobile absorbs the displacement in the axial direction that occurs when the automobile travels, and the expansion and contraction is a spline fit between the male shaft and the female shaft in order not to transmit the displacement or vibration on the steering wheel. The shaft is used as part of the steering mechanism. The telescopic shaft is required to reduce the rattling noise of the spline part, to reduce the rattling on the steering wheel, and to reduce the sliding resistance when sliding in the axial direction.

  Because of this, the nylon spline part of the telescopic shaft is coated with nylon film, and grease is applied to the sliding part to absorb or reduce metal noise, metal hitting sound, etc., and sliding resistance Have been reduced and the play in the rotational direction has been reduced. In this case, as a process of forming the nylon film, cleaning of the shaft → primer application → heating → nylon powder coating → rough cutting → finish cutting → selective fitting with the female shaft is performed. The final cutting process is performed by selecting a die in accordance with the accuracy of the already processed female shaft.

  However, such a spline-type telescopic shaft coated with a nylon film is sliding and has a high sliding force and is likely to be loose. Furthermore, it is necessary to perform selective cutting at the time of initial assembly, and it is difficult to adjust the sliding force and the backlash.

  For this reason, in Patent Document 1, a ball is disposed between the groove portion of the inner shaft and the ball via the elastic body in the groove portion provided in the outer periphery portion of the inner shaft and the inner periphery portion of the outer shaft. In addition, the sliding load of the male shaft and the female shaft is reduced by rolling the ball during movement in the axial direction, and the telescopic shaft for vehicle steering that restrains the ball and transmits torque during rotation. Is disclosed.

  However, since torque is also transmitted by balls, it is necessary to provide a number of balls that can withstand the torque. Therefore, it is difficult to reduce the size, and a sufficient collapse stroke cannot be taken at the time of a vehicle collision.

  Thus, in Patent Documents 2 to 4, a plurality of rows of axial grooves are formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft, respectively, in which the male shaft and the female shaft are non-rotatably and slidably fitted. Between the other plurality of rows of axial grooves formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft, respectively, while interposing a plurality of rolling elements via a leaf spring, A plurality of cylindrical bodies are interposed, thereby realizing a stable sliding load and reliably preventing backlash in the rotational direction so that torque can be transmitted in a highly rigid state.

Among these Patent Documents 2 to 4, in Patent Document 3, the male shaft is hollow and has a slit, and the male shaft is expanded radially outwardly in the hollow portion of the male shaft. A preloading means (for example, a spring pin) for elastically biasing is inserted. Thereby, backlash is suppressed.
JP 2001-050293 A JP 2003-063414 A JP 2003-247560 A JP 2003-336658 A

  However, in Patent Document 3, the preloading means is disposed inside the hollow of the male shaft, or is disposed between the rolling element interposed between the male shaft and the female shaft and the groove thereof. Therefore, there is a problem that the installation space is small.

  Further, the small installation space has a problem that the preload member, that is, the spring, has a low degree of design freedom. Furthermore, since the installation space is small, there is a problem that assembly is difficult.

  The present invention has been made in view of the above-described circumstances, and realizes a stable sliding load and reliably prevents backlash in the rotational direction, thereby allowing a high degree of freedom in design from high rigidity to low rigidity. An object of the present invention is to provide a telescopic shaft for vehicle steering that can apply a large preload and can improve assemblability.

In order to achieve the above object, a vehicle steering telescopic shaft according to claim 1 of the present invention is incorporated in a steering shaft of a vehicle, and a male shaft and a female shaft are fitted in a non-rotatable and slidable manner. In the telescopic shaft for steering,
A torque transmitting portion provided on each of the outer peripheral portion of the male shaft and the inner peripheral portion of the female shaft, and in contact with each other at the time of rotation;
A rolling element that is provided between the outer peripheral portion of the male shaft and the inner peripheral portion of the female shaft at a position different from the torque transmitting portion, and rolls when the two shafts move in the axial direction;
Preload applying means provided on the outer peripheral side of the female shaft and applying preload to the rolling element or the torque transmitting portion via the female shaft.

  The telescopic shaft for vehicle steering according to claim 2 of the present invention is characterized in that a slot or a slit is formed in a portion of the female shaft located on the inner diameter side of the preload applying means.

  In the telescopic shaft for vehicle steering according to claim 3 of the present invention, the torque transmitting portion is formed by an axial ridge formed on the outer peripheral portion of the male shaft and an axial direction formed on the inner peripheral portion of the female shaft. And a groove.

  The telescopic shaft for vehicle steering according to claim 4 of the present invention is characterized in that the torque transmission portion is formed in at least one row of groove directions formed on the outer peripheral portion of the male shaft and the inner peripheral portion of the female shaft, respectively, and the axial direction. And a cylindrical body that is interposed between the grooves and slides and slides in the axial relative movement of the two shafts.

  The telescopic shaft for vehicle steering according to claim 5 of the present invention is characterized in that the preload applying means applies preload inward in the radial direction.

  The telescopic shaft for vehicle steering according to claim 6 of the present invention is characterized in that the preload applying means includes an outer ring disposed outside the female shaft, and an elastic body interposed between the outer ring and the female shaft. It is characterized by comprising.

  The telescopic shaft for vehicle steering according to claim 7 of the present invention is characterized in that the preload applying means includes a wedge-shaped ring disposed outside the female shaft, and an elastic body that urges the wedge-shaped ring in the axial direction. When the elastic body urges the wedge-shaped ring in the axial direction, a preload is applied to the torque transmitting portion and the rolling element via the female shaft.

  According to the present invention, since the rolling element is interposed between the male shaft and the female shaft, and the rolling element is preloaded to such an extent that there is no backlash, the backlash between the male shaft and the female shaft is reliably prevented. In addition, when the male and female shafts move relative to each other in the axial direction, they can slide with a stable sliding load without rattling. The cylindrical body interposed between the two plays the main role of torque transmission.

  In addition, since preload applying means is provided on the outer periphery of the female shaft to apply preload to the rolling elements and the torque transmitting portion via the female shaft, the preload has a high degree of design freedom from high rigidity to low rigidity. As a result, the assemblability can be improved.

  Hereinafter, a telescopic shaft for vehicle steering according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG.

  3A is a side view of the female shaft according to the first embodiment of the present invention, FIG. 3B is a partial cross-sectional view of the female shaft during elastic deformation, and FIG. It is a side view of the female shaft which concerns on a modification, (d) is a fragmentary sectional view at the time of the elastic deformation of the said female shaft.

  As shown in FIG. 1, the telescopic shaft for vehicle steering includes a male shaft 1 and a female shaft 2 that are non-rotatable and slidably fitted to each other.

  As shown in FIG. 2, a plurality of axial ridges 14 extend from the outer peripheral surface of the male shaft 1. These axial ridges 14 are spline-fitting male parts, but may be serration-fitting male parts or simply for convex-concave fittings.

  On the inner peripheral surface of the female shaft 2, a plurality of axial grooves 6 are formed extending at positions facing the axial ridges 14 of the male shaft 1. These axial grooves 6 are female parts for spline fitting, but may be female parts for serration fitting or simply for uneven fitting.

  On the outer peripheral surface of the male shaft 1, three axial grooves 3 that are equally arranged at intervals of 120 degrees (phase) in the circumferential direction are formed to extend. Correspondingly, three axial grooves 5 that are equally arranged at intervals of 120 degrees (phase) in the circumferential direction are formed to extend on the inner peripheral surface of the female shaft 2. The axial groove 5 of the female shaft 2 has a substantially arc-shaped cross section or a Gothic arch shape.

  Between the axial groove 3 of the male shaft 1 and the axial groove 5 of the female shaft 2, a plurality of rigid spherical bodies 7 (rolling bodies, which roll when the two shafts 1 and 2 move in the axial direction relative to each other). Ball) is installed to roll freely.

  The small-diameter portion 1a at the end on the side where the male shaft 1 is inserted into the female shaft 2 is fixed by caulking with a retaining ring 11 so that the spherical body 7 does not fall off.

  A yoke 15a of the universal joint 15 is connected to the end of the male shaft 1 by welding or the like, and a yoke 16a of the universal joint 16 is connected to the end of the female shaft 2 by welding or the like.

  In the present embodiment, a cylindrical outer ring 20 is provided on the outer peripheral side of the female shaft 2. A slot 2a is formed in the portion of the female shaft 2 located on the inner diameter side of the outer ring 20. The slot 2a may have a shape formed parallel to the axial direction as shown in FIG. 3 (a), or may be formed parallel to the axial direction as shown in FIG. 3 (c). The shape which connects things may be sufficient. By providing such a slot 2a, as shown in FIGS. 3B and 3D, the female shaft 2 can be bent radially inward during preloading.

  A plurality of elastic bodies 30 are interposed between the outer ring 20 and the female shaft 2. The elastic body 30 is, for example, a coil spring, a leaf spring, a rod spring, an elastomer, a synthetic resin, or the like.

  Since the elastic body 30 is configured as described above, the elastic body 30 can apply preload to the spherical body 7 and the axial ridge 4 via the female shaft 2. That is, at the time of this preloading, the female shaft 2 is bent radially inward by the slot 2a, so that the female shaft 2 causes the spherical body 7 and the axial ridges 4 to move to the male shaft 1 by the urging force of the elastic body 30. Can be elastically pressed against.

  Thus, the telescopic shaft for vehicle steering according to the present embodiment is configured. In the telescopic shaft as described above, when the shaft rotates (during high torque transmission), the axial ridge 14 and the axial groove 6 are in contact with each other to form a torque transmission portion.

  Since the telescopic shaft of the present embodiment has such a structure, the male shaft 1 and the female shaft 2 are slidably in contact with each other at each torque transmitting portion due to the presence of the preload portion. During relative movement in the axial direction with respect to the female shaft 2, they slide with each other and the rolling element 7 can roll.

  Even if the axial ridge 14 formed on the male shaft 1 is formed on the female shaft 2 side and the axial groove 6 formed on the female shaft 2 is formed on the male shaft 1 side, the present embodiment The same action and effect can be obtained. Moreover, the curvature of the axial direction groove | channel 5 and the curvature of the rolling element 7 differ, and both may be formed so that a point contact may be carried out. Further, by applying grease to the sliding surface and the rolling surface, a lower sliding load can be obtained. Furthermore, it is desirable to apply grease during assembly. Further, the male shaft 1 may be subjected to heat treatment or surface treatment for wear resistance. Furthermore, in order to reduce sliding resistance, a coating such as PTFE (ethylene tetrafluoride) or molybdenum disulfide may be applied.

  The telescopic shaft of the present embodiment configured as described above is superior to the prior art in the following points.

  If the sliding surface is purely sliding as in the prior art, the preload load for preventing rattling could only be kept at a certain level. That is, the sliding load is the friction coefficient multiplied by the preload, and if the preload is increased to prevent rattling and improve the rigidity of the telescopic shaft, the sliding load will increase. This is because it falls into a vicious circle.

  In this respect, in the present embodiment, the preload portion employs a rolling mechanism of the spherical body 7 when the relative movement in the axial direction is performed, so that the preload is increased without causing a significant increase in the sliding load. be able to. As a result, it is possible to achieve the prevention of rattling and the improvement of rigidity that could not be achieved conventionally without increasing the sliding load.

  At the time of high torque transmission, the axial ridge 14 of the torque transmission portion plays a role of torque transmission by contacting the axial groove 6, and the female shaft 2 is elastically deformed in the preload portion to cause the spherical body 7 to move in the circumferential direction. To prevent backlash and transmit torque.

  For example, when torque is input from the male shaft 1, rattling is prevented because the preload of the elastic body 30 is applied at the initial stage.

  As the torque further increases, the axial ridge 14 of the torque transmitting portion and the side surface of the axial groove 6 come into strong contact with each other, and the axial ridge 14 receives a stronger reaction force than the spherical body 7, thereby transmitting torque. The part mainly transmits torque. Therefore, in this embodiment, it is possible to reliably prevent backlash in the rotational direction of the male shaft 1 and the female shaft 2, and to transmit torque in a highly rigid state.

Further, since the axial ridge 14 and the axial groove 6 are continuously contacted in the axial direction and receive the load during torque transmission, the contact pressure is kept lower than that of the rolling element 7 that receives the load by point contact. There are various effects. Therefore, the following items are superior to the conventional example in which the entire row has a ball rolling structure.
・ The damping effect at the sliding part is larger than that of the ball rolling structure. Therefore, vibration absorption performance is high.
-If the same torque is transmitted, the axial ridge 14 can keep the contact pressure lower, so that the axial length of the torque transmitting portion can be shortened and the space can be used effectively.
-If the same torque is transmitted, the contact pressure of the axial ridge 14 can be kept lower, so that an additional step for curing the axial groove surface of the female shaft by heat treatment or the like is unnecessary.
・ The number of parts can be reduced.
・ Assembly can be improved.
・ Assembly costs can be reduced.
-Since the torque transmission is mainly performed by the torque transmission part, the number of rolling elements 7 can be reduced and the collapse stroke can be increased.

Further, in terms of partially adopting the rolling elements 7, the following items are superior to the conventional example in which all the rows are spline fitted and all the rows slide.
・ Since rolling is used, sliding load can be kept low.
-Preload can be increased, and long-term rattling can be prevented and high rigidity can be obtained at the same time.

  In addition to the above description, the components of the telescopic shaft according to the present embodiment are preferably configured as shown in Table 1 and Table 2 below.

また、本実施の形態では、図１、図２に示すように、雄軸１の軸方向凸条１４は、その端部に、テーパー形状部Ｔを有している。また、軸方向凸条１４の両端部及び中間部では、その角部に、曲面形状部Ｒを有している。

Moreover, in this Embodiment, as shown in FIG. 1, FIG. 2, the axial direction protruding item | line 14 of the male shaft 1 has the taper-shaped part T in the edge part. Moreover, in the both ends and intermediate part of the axial ridge 14, it has the curved-surface-shaped part R in the corner | angular part.

  As shown in FIG. 2, the female shaft 2 is also formed at the corners of the ridge 6 a formed between the two axial grooves 6 and the standing wall 6 b on the end side of the axial groove 6. And has a curved surface portion R.

(Second Embodiment)
FIG. 4 is a cross-sectional view of the telescopic shaft for vehicle steering according to the second embodiment of the present invention (corresponding to a cross-sectional view taken along line II-II in FIG. 1).

  As is apparent from the drawings, the basic structure of this embodiment is the same as that of the first embodiment described above, and only differences will be described.

  In the present embodiment, three axial ridges 14 each having a substantially arc-like cross-sectional shape that are equally spaced at 120 degree intervals in the circumferential direction on the outer peripheral surface of the male shaft 1 are formed to extend. Correspondingly, three axial grooves 6 having a substantially arc-shaped cross section are formed on the inner peripheral surface of the female shaft 2 so as to face the three axial ridges 14 of the male shaft 1. ing. When sliding, the axial ridge 14 and the axial groove 6 are in principle non-contact with each other, but when high torque is transmitted, they are in contact with each other to form a torque transmission portion. The axial ridges 14 and the axial grooves 6 are substantially arc-shaped in cross section or Gothic arch shape, but may have other shapes.

  Moreover, since the outer peripheral surface of the axial ridge 14 is substantially arc-shaped, and the inner peripheral surface of the axial groove 6 is also substantially arc-shaped, and is arranged at three locations, the concavo-convex portion (axial ridge 14 The corners of the axial grooves 6) do not contact the edges of the corners and can prevent uneven wear. Furthermore, by arranging the axial ridges 14 at three equal positions, the three arc-shaped projections can receive a load evenly and transmit torque. Therefore, wear of the concavo-convex portions (axial ridges 14 and axial grooves 6) can be suppressed, and performance can be maintained over a long period of time.

  Furthermore, since the corners of the concavo-convex portions (the axial ridges 14 and the axial grooves 6) are not formed in the curved surface shape R, they have the curved surface shape (arc shape). The concavo-convex portions (the axial ridges 14 and the axial grooves 6) on the moving surface can slide smoothly without causing stick-slip. Other configurations, operations, and effects are the same as those in the above-described embodiment.

(Third embodiment)
FIG. 5 is a cross-sectional view of the telescopic shaft for vehicle steering according to the third embodiment of the present invention (corresponding to a cross-sectional view taken along line II-II in FIG. 1).

  As is apparent from the drawings, the basic structure of this embodiment is the same as that of the first embodiment described above, and only differences will be described.

  In the present embodiment, three axial grooves 4 that are equally arranged at intervals of 120 degrees (phase) in the circumferential direction are formed on the outer peripheral surface of the male shaft 1 so as to extend. Correspondingly, three axial grooves 6 that are equally arranged at intervals of 120 degrees (phase) in the circumferential direction are formed to extend on the inner peripheral surface of the female shaft 2.

  A plurality of rigid cylindrical bodies 8 (sliding bodies) that slide between the axial grooves 4 of the male shaft 1 and the axial grooves 6 of the female shaft 2 when the two shafts 1 and 2 move relative to each other in the axial direction. , A needle roller) is interposed with a minute gap. The axial grooves 4 and 6 have a substantially circular arc shape or a Gothic arch shape in cross section.

  In such a telescopic shaft, when the shaft rotates (when high torque is transmitted), the cylindrical body 8 and the axial grooves 4 and 6 come into contact with each other to constitute a torque transmitting portion.

  In addition, by providing the cylindrical body 8 instead of the axial ridges 14, the dimensions can be selectively adjusted, and only the cylindrical body 8 can be subjected to heat treatment or surface treatment, resulting in low cost. Can be achieved. Other configurations, operations, and effects are the same as those in the above-described embodiment.

(Fourth embodiment)
FIG. 6 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to a fourth embodiment of the present invention.

  As is apparent from the drawings, the basic structure of this embodiment is the same as that of the first embodiment described above, and only differences will be described.

  In the present embodiment, a holder 40 for holding a plurality of spherical bodies 7 is provided. Thereby, the assembling property can be improved and the cost can be reduced by shortening the assembling time. Further, by using the cage 40, the contact between the spherical bodies 7 is eliminated, and the sliding phenomenon of the spherical bodies 7 can be reduced. Therefore, a stable low slide load can be obtained. Furthermore, since the spherical bodies 7 can be aligned by the cage 40, the amount of rolling slide stroke can be obtained stably at all times. Other configurations, operations, and effects are the same as those in the above-described embodiment.

(Fifth embodiment)
FIG. 7 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to a fifth embodiment of the present invention.

  Fig.8 (a) is a side view of the female shaft which concerns on 5th Embodiment of this invention, (b) is a side view of the female shaft which concerns on a modification.

  9 is a cross-sectional view taken along line IX-IX in FIG.

  As is apparent from the drawings, the basic structure of this embodiment is the same as that of the first embodiment described above, and only differences will be described.

  In the present embodiment, the outer ring 20 is provided with adjusting means for adjusting the tightening force by expanding or reducing the diameter of the outer ring 20. That is, the adjusting means includes a cylindrical main body 21 provided on the outer periphery of the female shaft 2, a pair of flanges 22 and 22 protruding from the main bodies, and an adjusting bolt 23 for adjusting a distance between the pair of flanges 22 and 22. And.

  The elastic body 30 includes a plurality of thick portions 31 in the circumferential direction. Preload can be applied only to a portion where the thick portion 30 exists, that is, preload can be applied only to a phase where the spherical body 7 exists.

  In addition, a slit 2b or a slot 2a is formed in a portion of the female shaft 2 located on the inner diameter side of the outer ring 20. As shown in FIG. 8A, the slit 2b may have a shape formed by cutting from the end of the female shaft 2 and parallel to the axial direction. As shown in FIG. 8B, the slot 2a may be shaped so as to connect those formed parallel to the axial direction.

  Since it is configured in this way, the thick portion 31 of the elastic body 30 can apply a preload to the spherical body 7 via the female shaft 2. That is, at the time of this preloading, the female shaft 2 is bent radially inward by the slot 2a (slit 2b), whereby the female shaft 2 causes the spherical body 7 to be deformed by the urging force of the thick portion 31 of the elastic body 30. It can be elastically pressed against the male shaft 1.

  At this time, by rotating the adjustment bolt 23, the diameter of the main body 21 of the outer ring 20 can be reduced or increased, whereby the tightening force (preload) can be adjusted. Other configurations, operations, and effects are the same as those in the above-described embodiment.

(Sixth embodiment)
FIG. 10 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to the sixth embodiment of the present invention.

  11 is a cross-sectional view taken along line XI-XI in FIG.

  As is apparent from the drawings, the basic structure of this embodiment is the same as that of the first embodiment described above, and only differences will be described.

  In the present embodiment, the outer ring 20 is provided with adjusting means for adjusting the tightening force by expanding or reducing the diameter of the outer ring 20. That is, the adjusting means includes a cylindrical main body 21 provided on the outer periphery of the female shaft 2, a pair of flanges 22 and 22 protruding from the main bodies, and an adjusting bolt 23 for adjusting a distance between the pair of flanges 22 and 22. And.

  Moreover, the female shaft 2 is provided with a plurality of bulging portions 2c along the circumferential direction. A preload can be applied only to a portion where the bulging portion 2c is present, that is, a preload can be applied only to a phase where the spherical body 7 is present by the bulging portion 2c.

  Further, in the present embodiment, there is no elastic body, preload can be applied by the bulging portion 2c, and the preload can be adjusted by the adjusting means.

  Since it is configured in this way, the elastic body 30 can apply a preload to the spherical body 7 via the bulging portion 2 c of the female shaft 2. That is, at the time of this preload, the bulging portion 2c of the female shaft 2 bends radially inward by the slot 2a (slit 2b), whereby the bulging portion 2c of the female shaft 2 Can be pressed against.

  At this time, by rotating the adjustment bolt 23, the diameter of the main body 21 of the outer ring 20 can be reduced or increased, whereby the tightening force (preload) can be adjusted. Other configurations, operations, and effects are the same as those in the above-described embodiment.

(Seventh embodiment)
FIG. 12 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to a seventh embodiment of the present invention.

  13 is a cross-sectional view taken along line XIII-XIII in FIG.

  FIG. 14 is an exploded perspective view of a telescopic shaft for vehicle steering according to the seventh embodiment of the present invention.

  As is apparent from the drawings, the basic structure of this embodiment is the same as that of the first embodiment described above, and only differences will be described.

  The female shaft 2 includes a plurality of bulged portions 2c along the circumferential direction. A preload can be applied only to a portion where the bulging portion 2c is present, that is, a preload can be applied only to a phase where the spherical body 7 is present by the bulging portion 2c.

  An outer ring 20 is fixed to the outer periphery of the female shaft 2 so as not to move in the axial direction, and a wedge-shaped ring 50 is slidable in the axial direction. The wedge-shaped ring 50 and the outer ring 20 are formed with inclined surfaces 51 and 24 that are in sliding contact with each other. The wedge-shaped ring 50 is formed with a slit 52 so that the diameter can be reduced.

  A coil spring 32 is wound around the outer periphery of the female shaft 2, and a retaining ring 33 is fixed to one side of the coil spring 32 by welding or the like. It should be noted that the part indicated by reference numeral “34” may be welding or a retaining ring.

  The other side of the coil spring 32 biases the wedge-shaped ring 50 to the right in the axial direction (FIG. 12). Thus, when the wedge-shaped ring 50 is elastically pressed to the right in the axial direction (FIG. 12), the wedge-shaped ring 50 is slidably brought into contact with the inclined surfaces 51 and 24 of the outer ring 20 while the wedge-shaped ring 50 is radially inward. The diameter is reduced.

  As a result, the bulging portion 2c of the female shaft 2 is bent radially inward by the slot 2a (slit 2b) at the time of preloading, whereby the bulging portion 2c of the female shaft 2 Can be pressed against. Other configurations, operations, and effects are the same as those in the above-described embodiment.

(Eighth embodiment)
FIG. 15 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to an eighth embodiment of the present invention.

  FIG. 16A is a cross-sectional view taken along line XVI-XVI in FIG.

  As is apparent from the drawings, the basic structure of this embodiment is the same as that of the first embodiment described above, and only differences will be described.

  The female shaft 2 includes a plurality of bulged portions 2c along the circumferential direction. A preload can be applied only to a portion where the bulging portion 2c is present, that is, a preload can be applied only to a phase where the spherical body 7 is present by the bulging portion 2c.

  An outer ring 20 is fixed to the outer periphery of the female shaft 2 so as not to move in the axial direction, and a wedge-shaped ring 50 is slidable in the axial direction. The wedge-shaped ring 50 and the outer ring 20 are formed with inclined surfaces 51 and 24 that are in sliding contact with each other. The wedge-shaped ring 50 is formed with a slit 52 so that the diameter can be reduced. Further, the part indicated by reference numeral “34” may be welding or a retaining ring.

  A retaining ring 35 is fixed to the end of the male shaft 1, and a coil spring 32 is interposed between the retaining ring 35 and the wedge-shaped ring 50.

  As described above, in the present embodiment, the male shaft 1 is inserted into the female shaft 2 and assembled, and the preload of the coil spring 32 is generated when the male shaft 1 is attached to the vehicle body.

  From the above, when the wedge-shaped ring 50 is elastically pressed to the left in the axial direction (FIG. 15) by the coil spring 32, the wedge-shaped ring 50 is slidably brought into sliding contact with the inclined surfaces 51, 24 of the outer ring 20. The diameter is reduced inward in the radial direction.

  As a result, the bulging portion 2c of the female shaft 2 is bent radially inward by the slot 2a (slit 2b) at the time of preloading, whereby the bulging portion 2c of the female shaft 2 Can be pressed against. Other configurations, operations, and effects are the same as those in the above-described embodiment.

  FIG. 16B is a cross-sectional view of a telescopic shaft for vehicle steering according to a modification of the eighth embodiment (corresponding to a cross-sectional view taken along line XVI-XVI in FIG. 15).

  In this modification, the flat surface 53 is formed on the inner peripheral surface of the wedge-shaped ring 50 in the circumferential direction without providing the bulging portion 2 c on the female shaft 2. Preload can be applied only to a portion where the flat surface 53 exists, that is, preload can be applied only to a phase where the spherical body 7 exists.

(Ninth embodiment)
FIG. 17 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to the ninth embodiment of the present invention.

  As is clear from the drawings, the basic structure of this embodiment is the same as that of the first or third embodiment described above, and only differences will be described.

  In the present embodiment, a bent piece 2d is formed at the end of the female shaft 2, and a spring mounting portion 36 is provided at the end of the male shaft 1, and the bent piece 2d, the spring A coil spring 37 is interposed between the mounting portion 36.

  As described above, in the present embodiment, the male shaft 1 is inserted into the female shaft 2 and assembled, and the preload of the coil spring 37 is generated when the male shaft 1 is attached to the vehicle body.

  From the above, when the bent piece 2d of the female shaft 2 is elastically pulled by the coil spring 37, the bent piece 2d is pulled slightly inward in the radial direction as indicated by the arc-shaped arrow.

  As a result, during preloading, the female shaft 2 is deflected radially inward by the slot 2a (slit 2b), whereby the female shaft 2 can press the spherical body 7 against the male shaft 1. Other configurations, operations, and effects are the same as those in the above-described embodiment.

  FIG. 18 is a schematic side view of a steering apparatus equipped with a vehicle steering telescopic shaft according to a ninth embodiment of the present invention.

  On the steering column 61, a steering shaft 63 having a steering wheel 62 mounted at the rear end is rotatably supported.

  An intermediate shaft 65 according to the present invention is connected to the front end of the steering shaft 63 via the universal joint 16. A rack and pinion type steering gear 67 is connected to the lower end of the intermediate shaft 65 via a universal joint 15, and a wheel (not shown) is connected to the steering gear 67 via a tie rod (not shown). Are connected so that the wheels can be steered.

  The steering column 61 is supported by a vehicle body side bracket 71 so that telescopic adjustment can be performed. The electric power steering apparatus includes an electric motor 72, a gear box 73, and the like.

(Tenth embodiment)
FIG. 19 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to the tenth embodiment of the present invention.

  The telescopic shaft according to the present embodiment does not include the outer ring 20 but has a structure in which the male shaft 1 and the female shaft 2 have a spring constant in the axial direction when attached to the vehicle body.

  The spherical body 7 is urged radially outward by a leaf spring 9 provided in the axial groove 3 of the male shaft 1, thereby preventing the spherical body 7 from rattling or the like.

  Thus, the telescopic shaft can be expanded and contracted with an extremely low sliding force, such as using the rolling of the spherical body 7.

  In the present embodiment, in addition, a coil spring 81 is interposed between the yoke 16 a at the end of the female shaft 2 and the end of the male shaft 1. The coil spring 81 may be tension or compression.

  Thereby, a damping mechanism can be added to the telescopic shaft with extremely low sliding force.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible.

It is a longitudinal cross-sectional view of the telescopic shaft for vehicle steering which concerns on 1st Embodiment of this invention. It is a cross-sectional view along the II-II line of FIG. (A) is related with 1st Embodiment of this invention, and is a side view of a female shaft, (b) is a fragmentary sectional view at the time of the elastic deformation of the said female shaft, (c) is a modification. It is a side view of the female shaft which concerns on this, (d) is a fragmentary sectional view at the time of the elastic deformation of the said female shaft. It is sectional drawing of the expansion-contraction shaft for vehicle steering which concerns on 2nd Embodiment of this invention (equivalent to the cross-sectional view along the II-II line of FIG. 1). It is sectional drawing of the expansion-contraction shaft for vehicle steering which concerns on 3rd Embodiment of this invention (equivalent to the cross-sectional view along the II-II line of FIG. 1). It is a longitudinal cross-sectional view of the telescopic shaft for vehicle steering which concerns on 4th Embodiment of this invention. It is a longitudinal cross-sectional view of the telescopic shaft for vehicle steering which concerns on 5th Embodiment of this invention. (A) is a side view of the female shaft which concerns on 5th Embodiment of this invention, (b) is a side view of the female shaft which concerns on a modification. It is sectional drawing along the IX-IX line of FIG. It is a longitudinal cross-sectional view of the telescopic shaft for vehicle steering which concerns on 6th Embodiment of this invention. It is sectional drawing along the XI-XI line of FIG. It is a longitudinal cross-sectional view of the telescopic shaft for vehicle steering which concerns on 7th Embodiment of this invention. It is sectional drawing along the XIII-XIII line | wire of FIG. It is a disassembled perspective view of the expansion-contraction shaft for vehicle steering which concerns on 7th Embodiment of this invention. It is a longitudinal cross-sectional view of the telescopic shaft for vehicle steering which concerns on 8th Embodiment of this invention. (A) is sectional drawing which followed the XVI-XVI line | wire of FIG. (B) is sectional drawing of the expansion-contraction shaft for vehicle steering which concerns on the modification of 8th Embodiment (equivalent to sectional drawing along the XVI-XVI line of FIG. 15). It is a longitudinal cross-sectional view of the telescopic shaft for vehicle steering which concerns on 9th Embodiment of this invention. It is a typical side view of a steering device equipped with a telescopic shaft for vehicle steering according to a ninth embodiment of the present invention. It is a longitudinal cross-sectional view of the telescopic shaft for vehicle steering which concerns on 10th Embodiment of this invention.

Explanation of symbols

1 male shaft 1a small diameter portion 2 female shaft 2a slot 2a slit 2c bulging portion 2d bent piece 3 axial groove 4 axial groove 5 axial groove 6 axial groove 7 spherical body (ball, rolling element)
8 Cylindrical body (sliding body, needle roller)
DESCRIPTION OF SYMBOLS 11 Retaining ring 14 Axial ridge 15, 16 Universal joint 15a, 16a Yoke 20 Outer ring 21 Main body 22 Flange 23 Adjustment bolt 24 Inclined surface 30 Elastic body 31 Thick part 32 Coil spring 33 Retaining ring 34 Welding part 35 Retaining ring 36 Spring Mounting portion 37 Coil spring 40 Cage 50 Wedge ring 51 Inclined surface 52 Slit 53 Flat surface 61 Steering column 62 Steering wheel 63 Steering shaft 65 Intermediate shaft 67 Steering gear 71 Car body side bracket 72 Electric motor 73 Gear box

Claims (7)

A telescopic shaft for vehicle steering that is incorporated in a steering shaft of a vehicle and has a male shaft and a female shaft that are non-rotatable and slidably fitted to each other.
A torque transmitting portion provided on each of the outer peripheral portion of the male shaft and the inner peripheral portion of the female shaft, and in contact with each other at the time of rotation;
A rolling element that is provided between the outer peripheral portion of the male shaft and the inner peripheral portion of the female shaft at a position different from the torque transmission portion, and rolls in the axial relative movement of the two shafts;
A telescopic shaft for vehicle steering, comprising: a preload applying means which is provided on an outer peripheral side of the female shaft and applies a preload to the rolling element or the torque transmitting portion via the female shaft.   The telescopic shaft for vehicle steering according to claim 1, wherein a slot or a slit is formed in a portion of the female shaft located on the inner diameter side of the preload applying means.   The said torque transmission part consists of the axial direction protrusion formed in the outer peripheral part of the said male axis | shaft, and the axial groove | channel formed in the inner peripheral part of the said female axis | shaft. The telescopic shaft for vehicle steering described in 1.   The torque transmitting portion is interposed between at least one row of groove directions formed on the outer peripheral portion of the male shaft and the inner peripheral portion of the female shaft, and between the axial grooves. The telescopic shaft for vehicle steering according to claim 1 or 2, comprising a cylindrical body that slides and slides when moving.   The telescopic shaft for vehicle steering according to any one of claims 1 to 4, wherein the preload applying means applies preload inward in the radial direction.   The said preload provision means consists of the outer ring arrange | positioned on the outer side of the said female shaft, and the elastic body interposed between the said outer ring and the said female shaft, The any one of Claim 1 thru | or 5 characterized by the above-mentioned. The telescopic shaft for vehicle steering according to claim 1.   The preload applying means includes a wedge-shaped ring disposed outside the female shaft and an elastic body that urges the wedge-shaped ring in the axial direction, and the elastic body urges the wedge-shaped ring in the axial direction. The telescopic shaft for vehicle steering according to any one of claims 1 to 6, wherein a preload is applied to the torque transmitting portion and the rolling element via the female shaft.

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