WO2006009230A1

WO2006009230A1 - Telescopic shaft for vehicle steering

Info

Publication number: WO2006009230A1
Application number: PCT/JP2005/013428
Authority: WO
Inventors: Takatsugu Yamada; Kiyoshi Sadakata
Original assignee: Nsk Ltd.
Priority date: 2004-07-21
Filing date: 2005-07-14
Publication date: 2006-01-26
Also published as: JPWO2006009230A1

Abstract

A telescopic shaft for vehicle steering, in which a section at which a female shaft and a male shaft are fitted is reliably sealed to prevent entry of rain water, muddy water, and dust into the fit section and restricts variation in slide load. A seal member (S) is formed from an elastic body such as rubber and is composed of an axially telescopable bellows-like section (20), a fixation section (21) formed at one end of the bellows-like section (20) and fixing the bellows-like section (20) to a recessed step section (10a) of a female shaft (10), and a seal section (30) formed at the other end of the bellows-like section (20) and in contact, with appropriate interference, with the outer peripheral surface of a male shaft (11). In a normal use region (region where very small displacement such as vibration absorption occurs), a change in volume, such as compression of air, does not occur in the inner space of the bellows-like section (20), so that variation in a slide load on the telescopic shaft can be restricted. On the other hand, at the time of installation of the telescopic shaft on a vehicle or when the telescopic shaft slides greatly as in a collision, the seal section (30) slides on the outer peripheral surface of the male shaft (11).

Description

Description Telescopic shaft for vehicle steering Technical Field

The present invention is incorporated in a steering shaft of a vehicle, and a female shaft and a male shaft are fitted so as not to rotate relative to each other and slidable, and the fitting portion of the female / male shaft is sealed to allow rain into the fitting portion. The present invention relates to a telescopic shaft for vehicle steering provided with a seal member that prevents intrusion of water or the like. Background art

In a vehicle steering system, the intermediate shaft is composed of a telescopic shaft that is spline-fitted, etc., and absorbs axial displacement that occurs when the vehicle travels, and does not transmit the displacement or vibration to the steering wheel. It ’s like that.

In Japanese Patent Laid-Open No. 6-2 4 1 2 3 8, the intermediate shaft is composed of a spline-fitted female shaft and a male shaft, and a substantially cap-shaped sealing member is attached to the end of the female shaft. The seal member is composed only of an elastic body such as rubber. The lip portion of this seal member is in sliding contact with the outer peripheral surface of the male shaft (contacting with frictional force), thereby preventing rainwater, muddy water, dust, etc. from entering the fitting portion of the female / male shaft. It is preventing. Incidentally, FIG. 12 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to a conventional example. 13A is a cross-sectional view of the female / male shaft shown in FIG. 12, and FIG. 13B is an enlarged vertical cross-sectional view of the end of the male shaft shown in FIG.

On the outer peripheral surface of the male shaft 11, three axial grooves 43 are arranged so as to be evenly arranged at intervals of 120 degrees in the circumferential direction (phase). Correspondingly, three axial grooves 45 that are equally arranged at intervals of 120 degrees in the circumferential direction (phase) are formed to extend on the inner circumferential surface of the female shaft 10.

Between the axial groove 4 3 of the male shaft 1 1 and the axial groove 4 5 of the female shaft 10, both shafts 1 0, 1 A plurality of rigid spherical bodies 47 (rolling bodies, poles) that roll during the relative axial movement of 1 are interposed so as to be freely rollable. The axial groove 45 of the female shaft 10 has a substantially arc-shaped cross section or a Gothic arch shape.

The axial groove 4 3 of the male shaft 11 is composed of a pair of inclined flat side surfaces 4 3 a and a bottom surface 4 3 b formed flat between the pair of flat side surfaces 4 3 a. .

A leaf spring 49 for contacting and preloading the spherical body 47 is interposed between the axial groove 43 of the male shaft 11 and the spherical body 47.

The leaf spring 4 9 is separated from the spherical body side contact portion 4 9 a that contacts the spherical body 47 at two points, and is spaced apart from the spherical body side contact portion 4 9 a at a predetermined interval in the circumferential direction. With male shaft 1 1 axial groove 4 3 planar side surface 4 3 a groove surface side contact portion 4 9 b that contacts a, spherical body side contact portion 4 9 a and groove surface side contact portion 4 9 b And a bottom portion 4 9 d facing the bottom surface 4 3 b of the axial groove 4 3. ,

The urging portion 4 9 c is a substantially U-shaped bent shape that is bent in a substantially arc shape, and the bent-side urging portion 4 9 c causes the spherical body side contact portion 4 9 a and the groove surface to be bent. The side contact portions 4 9 b can be elastically biased so as to be separated from each other.

As shown in Fig. 1 3 A, the outer surface of the male shaft 1 1 is formed by extending three axial grooves 4 4 equally spaced at intervals of 120 degrees in the circumferential direction (phase). is there. Correspondingly, three axial grooves 46 are equally formed on the inner peripheral surface of the female shaft 10 so as to be evenly spaced at intervals of 120 degrees in the circumferential direction (phase).

A rigid cylindrical body that slides and slides between the axial groove 4 4 of the male shaft 1 1 and the axial groove 4 6 of the female shaft 1 0 when the two shafts 1 0 and 1 1 move in the axial direction. 4 8 (Sliding body, Needle port-La) is inserted with a small gap. These axial grooves 4 4 and 4 6 have a substantially circular arc shape or a Gothic arch shape in cross section.

Further, as shown in FIGS. 12 and 13B, a small-diameter portion 1 1 b is formed at the end of the male shaft 1 1, and the small-diameter portion 1 1 b has an elastic plate 4 1 and A pair of flat plates 4 2, 4 2 and A stopper member consisting of is fitted and fixed by caulking. This one stopper member is configured to apply an appropriate preload while being regulated in the axial direction of the needle roller 48, and serves as a stopper in the axial direction of the spherical body 47.

In the telescopic shaft configured as described above, the spherical body 47 is interposed between the male shaft 11 and the female shaft 10, and the spherical body 47 is loosely separated from the female shaft 10 by the leaf spring 4 9. Since it is preloaded to the extent that there is no sticking, it is possible to reliably prevent backlash between the male shaft 1 1 and the female shaft 10 during low torque transmission, and the male shaft 1 1 and female shaft 1 0. When moving relatively in the axial direction, it can slide with a stable sliding load without rattling.

At the time of high torque transmission, the plate panel 4 9 elastically deforms to restrain the spherical body 4 7 in the circumferential direction, and three rows of cylindrical bodies 4 8 interposed between the male shaft 11 and the female shaft 10 It plays the role of main torque transmission.

For example, when torque is input from the male shaft 1 1, the plate panel 4 9 is preloaded in the initial stage, so there is no backlash, and the leaf spring 4 9 generates a reaction force against the torque. To communicate. At this time, overall torque transmission is performed in a state where the transmission torque between the male shaft 11, the leaf spring 4 9, the spherical body 4 7, and the female shaft 10 is balanced.

As the torque further increases, there is no clearance in the rotational direction of the male shaft 1 1 and female shaft 10 through the cylindrical body 48, and the subsequent torque increases are represented by the male shaft 1 1 and female shaft 1 0. The cylindrical body 48 is transmitted via. Therefore, it is possible to reliably prevent backlash in the rotational direction of the male shaft 11 and the female shaft 10 and to transmit torque in a highly rigid state.

From the above, since the cylindrical body 48 is provided in addition to the spherical body 47, a large part of the load can be supported by the cylindrical body 48 when a large torque is input. Accordingly, the contact pressure between the axial groove 45 of the female shaft 10 and the spherical body 47 can be kept low, and torque can be transmitted in a highly rigid state when a large torque is loaded. In this way, it is possible to realize a stable sliding load, reliably prevent the rotation direction from being squeezed, and transmit torque in a highly rigid state. P2005 / 013428

4 In the telescopic shaft configured as described above, the substantially cap-shaped seal member 100 disclosed in Japanese Patent Laid-Open No. 6-2 4 1 2 3 8 is attached to the end of the female shaft 10. is there. The seal member 100 is composed only of an elastic body such as rubber, and is fitted on the fitting portion 10 0 1 fitted on the end of the female shaft 10 and on the outer peripheral surface of the male shaft 11. And a slidable contact seal portion 102 that performs a sealing action by contacting with frictional force. This prevents rainwater, muddy water, dust, etc. from entering the fitting part of the female / male shaft.

However, in the seal member 100 disclosed in FIG. 12 (Japanese Patent Laid-Open No. 6-2 4 1 2 3 8), the joint 1 1 1 of the universal joint 110 is welded to the opposite side. Therefore, the interior of the female shaft 10 is a hermetically sealed space.

As a result, when the male shaft 1 1 slides, there is no air escape in the internal space of the sealed female shaft 10 and air cannot enter or exit, so volume change such as air compression occurs. There is a problem when fluctuations in the sliding load appear, such as the sliding load on the male shaft 1 1 increases according to the sliding amount of the male shaft 1 1. Disclosure of the invention

The present invention has been made in view of the circumstances as described above, and reliably seals the fitting portion of the female / male shaft to prevent intrusion of rainwater, muddy water, dust, or the like into the fitting portion. An object of the present invention is to provide a telescopic shaft for vehicle steering that can suppress fluctuations in sliding load.

In order to achieve the above object, the vehicle steering extension shaft according to the first aspect of the present invention is incorporated in a steering shaft of a vehicle, and a vehicle steering shaft in which a male shaft and a female shaft are fitted non-rotatably and slidably. For telescopic shaft

The telescopic shaft is

A preload torque transmission unit that transmits the steering torque while preloading between the two shafts when the steering torque is a predetermined value or less;

When the steering torque exceeds a predetermined value, the steering torque is A rigid torque transmitting portion for transmitting the torque; and

One end is fixed to the male shaft, the fitting portion of the male shaft and the two shafts is covered, and an axially expandable / contractible bellows-shaped dustproof boot having the other end fixed to the female shaft is provided. And

In the telescopic shaft for vehicle steering according to the present invention, the preload torque transmitting portion includes an elastic body between at least one row of axial grooves formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft, respectively. Through the first torque transmission member,

The rigid torque transmission part is

It is preferable that a second torque transmission member is interposed between at least one other groove direction formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft.

In the telescopic shaft for vehicle steering according to the present invention, the first torque transmission member is a rolling element that rolls in the axial relative movement of the two shafts.

The second torque transmitting member is preferably a sliding body that slides when the two wheels move in the axial direction relative to each other.

In the telescopic shaft for vehicle steering according to the present invention, the rigid torque transmitting portion is provided on each of the outer peripheral portion of the male shaft and the inner peripheral portion of the female shaft, and transmits torque by contacting each other during rotation. And

The preload torque transmission unit is

Provided between the outer periphery of the male shaft and the inner periphery of the female shaft at a position different from the rigid torque transmitting portion, and rolls when the male shaft and the female shaft move in the axial direction. Preferably, the rolling element includes: an elastic body that is disposed adjacent to the rolling element in a radial direction, and applies a preload to the male shaft and the female shaft via the rolling element.

The telescopic shaft for vehicle steering according to the second aspect 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, and the fitting portions of both shafts are sealed. In the telescopic shaft for vehicle steering equipped with a seal member for preventing rainwater and the like from entering the fitting portion, The sealing member is:

A bellows-like portion that covers the fitting portion of both shafts and is extendable in the axial direction;

And a seal portion that is formed at one end of the bellows-like portion and contacts the outer peripheral surface of either of the two shafts with an appropriate tightening margin.

In the telescopic shaft for vehicle steering according to the second aspect of the present invention, the other end of the bellows-like portion is fixed to the outer peripheral surface of the female shaft,

It is preferable that the seal portion contacts the outer peripheral surface of the male shaft with an appropriate margin.

In the vehicle steering telescopic shaft according to the second aspect of the present invention, it is preferable that the seal portion has a pair of lip portions between which a grease reservoir portion is formed.

In the telescopic shaft for vehicle steering according to the second aspect of the present invention, the seal portion preferably has a metal ring embedded therein.

In the vehicle steering telescopic shaft according to the second aspect of the present invention, it is preferable that a solid lubricating film is coated on the lip portion of the seal portion.

In the vehicle steering telescopic shaft according to the second aspect of the present invention, it is preferable that the outer peripheral surface of the male shaft that is in contact with the seal portion is coated with a solid lubricating film.

In the vehicle steering telescopic shaft according to the second aspect of the present invention, it is preferable that the seal portion has a grease ring exposed to the seal surface and adjacent to the lip portion.

In the vehicle steering telescopic shaft according to the second aspect of the present invention, the seal portion includes a metal ring embedded in the interior thereof, and is exposed to the seal surface and adjacent to the lip portion, and is press-fitted into the metal ring. It is preferable to have a certain resin ring. In the vehicle steering telescopic shaft according to the second aspect of the present invention, the seal portion includes a metal ring embedded in the seal portion and a metal ring exposed to the seal surface and pressed against the metal ring. It is preferable to have a resin ring or a coasting ring that is inserted or fixed. In the telescopic shaft for vehicle steering according to the second aspect of the present invention, the relationship between the axial displacement resistance of the bellows-like portion and the sliding resistance of the seal portion is:

At a slight displacement, the axial displacement resistance of the bellows-shaped part is smaller than the sliding resistance of the seal part,

When it becomes larger than that at the time of slight displacement, the sliding resistance of the seal portion is smaller than the axial displacement resistance of the bellows-shaped portion,

It is preferable to set so that

In the vehicle steering telescopic shaft according to the second aspect of the present invention, when the two shafts extend greatly to each other, the internal space of the bellows-like portion becomes negative pressure, and the seal portion slides. on the other hand,

When the two shafts are greatly contracted with each other, it is preferable that the seal portion slides while the internal space of the bellows-like portion becomes a positive pressure.

According to the present invention, there is provided an axially expandable / contractible bellows-shaped dustproof boot that fixes one end to the male shaft, covers the fitting portion between the male shaft and both shafts, and fixes the other end to the female shaft. Yes. Alternatively, the seal member is formed on the one end of the bellows-shaped portion that covers the fitting portions of both shafts and is extendable in the axial direction, and is appropriately formed on the outer peripheral surface of either shaft. And a seal portion that comes into contact with a tight margin.

Therefore, the fitting part of the female / male shaft is securely sealed to prevent intrusion of rainwater, muddy water, dust, etc. into the fitting part, and in the internal space of the dustproof boot or seal member, air compression, etc. There is no change in volume, and fluctuations in sliding load can be suppressed. Brief Description of Drawings

1A is a side view of a vehicle steering apparatus according to the present invention, FIG. 1B is a cross-sectional view of an accordion-shaped portion according to an example, and FIG. 1C is a cross-section of an accordion-shaped portion according to another example. In the figure JP2005 / 013428

8th.

FIG. 2 is a longitudinal sectional view of the telescopic shaft for vehicle steering according to the first embodiment of the present invention.

FIG. 3A is a longitudinal sectional view of a telescopic shaft for vehicle steering according to a second embodiment of the present invention, and FIG. 3B is an enlarged sectional view of the seal member shown in FIG. 3A.

FIG. 4A and FIG. 4B relate to a third embodiment of the present invention, and are longitudinal sectional views according to modifications of the female / male shaft, respectively.

FIG. 5 is an enlarged cross-sectional view of the female / male shaft shown in FIG. 4A.

FIG. 6A and FIG. 6B are enlarged sectional views of the seal member according to the fourth embodiment of the present invention.

FIG. 7A and FIG. 7B are enlarged cross-sectional views of the seal member according to the fourth embodiment of the present invention.

FIG. 8A is a longitudinal sectional view of a telescopic shaft for vehicle steering according to a fifth embodiment of the present invention. FIGS. 8B and 8C are enlarged sectional views of the seal member shown in FIG. 8A, respectively. It is. ·

FIG. 9A is a longitudinal sectional view of a telescopic shaft for vehicle steering according to a sixth embodiment of the present invention. FIGS. 9B and 9C are enlarged sectional views of the seal member shown in FIG. 9A, respectively. It is.

FIG. 10A, FIG. 10B, and FIG. 10C are longitudinal sectional views of the telescopic shaft for vehicle steering according to the seventh embodiment of the present invention.

FIGS. 11A and 11B are longitudinal sectional views of a telescopic shaft for vehicle steering according to a seventh embodiment of the present invention.

FIG. 12 is a longitudinal sectional view of a telescopic shaft for vehicle steering according to a conventional example.

13A is an enlarged cross-sectional view of the female / male shaft shown in FIG. 12 and FIG. 13B is an enlarged vertical cross-sectional view of the end of the male shaft shown in FIG. BEST MODE FOR CARRYING OUT THE INVENTION

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

(Overall configuration diagram of vehicle steering system)

1A is a side view of a vehicle steering apparatus according to the present invention, FIG. 1B is a cross-sectional view of an accordion-shaped portion according to an example, and FIG. 1C is a cross-section of an accordion-shaped portion according to another example. It is a figure.

On the steering column 1, a steering shaft 3 having a steering wheel 2 mounted on one side of the upper is rotatably supported.

A telescopic intermediate shaft 5 is connected to the lower side of the steering shaft 3 via a universal joint 4. A rack and pinion type steering gear 7 is connected to the lower end of the intermediate shaft 5 via a universal joint 6, and a wheel (not shown) is connected to the steering gear 7 via a tie rod (not shown). ) Are connected so that the wheels can be steered.

The intermediate shaft 5 has a female shaft 10 and a male shaft 11 that are non-rotatable and slidably fitted. The female shaft 10 is on the upper side of the vehicle, and the male shaft 11 is on the lower side of the vehicle. It is set to be. Thereby, as will be described later, it is possible to effectively prevent water or the like from entering the intermediate shaft 5.

Further, the fitting portion of both shafts 10 and 11 is formed with an accordion-like portion 20 that is extendable in the axial direction, and an outer peripheral surface of the male shaft 11 1 formed at one end of the accordion-like portion 20. A seal member S composed of a seal portion 30 that comes into contact with a moderate tightening margin is attached. Instead of the seal member S, a dustproof boot B shown in FIG. 2 may be attached.

The bellows-shaped portion 20 of the seal member S or dustproof block B may have a plurality of corrugated shapes as shown in FIG. 1B, or a single chevron shape as shown in FIG. 1C. It may be in shape.

(First embodiment) FIG. 2 is a longitudinal sectional view of the telescopic shaft for vehicle steering according to the first embodiment of the present invention.

The telescopic shaft itself according to this embodiment has the same configuration as the telescopic shaft shown in FIGS. 12 and 13 A and 13 B, and the description thereof is omitted. However, instead of the cylindrical body 48 shown in Fig. 1 2 and Fig. 1 3 A, 1 3 B, it has a convex strip shape such as a circular arc section formed directly on the male shaft 1 1 like spline fitting. It may be.

In the present embodiment, an axial direction in which one end is fixed to the male shaft 11 and the fitting portion between the male shaft 11 and both shafts 10 and 11 is covered and the other end is fixed to the female shaft 10 An elastic bellows-shaped dustproof boot B is provided.

The dustproof boot B is formed of an elastic body such as rubber, and has an accordion-like bellows-like portion 20 that is freely stretchable in the axial direction, and a concave step portion of the female shaft 10 that is formed at one end of the bellows-like portion 20. A bellows-like part 2 1 for fixing the bellows-like part 1 0 a and a bellows-like part 2 formed on the other end of the bellows-like part 20 and a concave step part 1 1 a of the male shaft 1 1 And a fixing portion 22 for fixing 0.

The telescopic shaft shown in Fig. 2 (ie Fig. 12 and Fig. 13 A, 13 B) slides using rolling, so the sliding load is very light and stable. In other words, the slide load varies little within the sliding range and is characterized by a low sliding load. Since the dustproof boot B having the bellows-shaped part 20 is mounted on the telescopic shaft of such a low sliding load, the volume change such as air compression occurs in the internal space of the dustproof boot B. No fluctuation in sliding load on the telescopic shaft can be suppressed. Accordingly, it is possible to use the telescopic shaft outdoors while maintaining the characteristics of the telescopic shaft with a low sliding load as described above.

(Second embodiment)

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

In the second embodiment, the fitting portions of both shafts 10 and 11 are formed at the end of the bellows-like portion 20 and the bellows-like portion 20 that are extendable in the axial direction. A seal member S composed of a seal portion 30 that contacts the outer peripheral surface of the male shaft 11 with an appropriate tightening margin is attached.

The seal member S is formed of an elastic body such as rubber, and has a bellows-like portion 20 that can be expanded and contracted in the axial direction. 1 0 a A bellows-like part 20 for fixing the bellows-like part 20 and a seal formed on the other end of the bellows-like part 20 and contacting the outer peripheral surface of the male shaft 11 with an appropriate tightening margin Part 30. Further, as shown in FIG. 3B, the seal portion 30 includes a plurality of lip portions 31, 31, and 31.

With this configuration, in the normal use region (small displacement region such as vibration absorption), the internal space of the bellows-shaped portion 20 does not cause a volume change such as air compression, and the telescopic shaft The fluctuation of the sliding load can be suppressed.

On the other hand, when the telescopic shaft slides greatly, such as when assembled to a vehicle or at the time of a collision, the seal portion 30 is configured to slidably contact the outer peripheral surface of the male shaft 11. . By changing the size of the bellows-shaped part 20, the volume of the internal space of the bellows-shaped part 20 can be increased, and the normal use area (small displacement area such as vibration absorption) can be increased or decreased. In addition, it is possible to reduce fluctuations in the sliding load when the vehicle is assembled. Furthermore, by making the bellows-like portion 20 an optimum size, it is possible to improve the mountability as compared with the first embodiment described above.

(Third embodiment)

FIG. 4A and FIG. 4B relate to a third embodiment of the present invention, and are longitudinal sectional views according to modifications of the female / male shaft, respectively. FIG. 5 is an enlarged cross-sectional view of the female / male shaft shown in FIG. 4A. 4A and 4B is the same as that of the second embodiment described above in the modification of the female and male shafts. (Screw adjustable slider)

As shown in FIG. 4A and FIG. 5, the end of the male shaft 11 is formed in a hollow or cylindrical shape, and a plurality of (in the illustrated example, four) slits 51 are formed in the axial direction. It is extended. As a result, the end of the male shaft 11 can be reduced or expanded.

A screw-type diameter adjusting mechanism is provided at the hollow end of the male shaft 11. That is, as shown in FIG. 5, a nut member 52 having a female screw on its inner peripheral surface is erected in the radial direction, and an adjusting bolt 53 is screwed into the nut member 52. .

A support member 54 is provided opposite to the nut member 52, and the tip of the adjustment port 53 is brought into contact with the support member 54 so that it can be pressed.

Therefore, when the adjustment port 53 is adjusted to reduce the pressing force from the adjustment port 53 to the support member 54, the hollow end portion of the male shaft 11 provided with the slit 51 is reduced in diameter. . As a result, the sliding resistance of the female and male shafts 10 and 11 can be reduced.

When the adjustment bolt 53 is adjusted to increase the pressing force from the adjustment bolt 53 to the support member 54, the hollow end portion of the male shaft 11 provided with the slit 51 expands. As a result, the sliding resistance of the female / male shafts 10 and 11 can be increased.

(Spline slider)

As shown in FIG. 4B, the intermediate shaft 5 includes a female shaft 10 and a male shaft 11 that are spline-fitted. A female spline portion 10 c is formed on the inner peripheral surface of the female shaft 10, and a male spline portion 1 1 c is formed on the outer peripheral surface of the male shaft 1 1. 0 and 11 are configured to be slidable and not rotatable relative to each other. The male spline portion 1 1 c of the male shaft 1 1, the female spline portion 1 0 c of the female shaft 1 0, or both the shafts 1 0 and 1 1 are coated with resin or a solid lubricant film. May be. Thus, the sliding resistance can be reduced when the female / male shafts 10 and 11 are rocked.

(Fourth embodiment)

FIG. 6A, FIG. 6B, FIG. 7A, and FIG. 7B are enlarged cross-sectional views of the seal member according to the fourth embodiment of the present invention. The basic structure of this embodiment is the same as that of the second embodiment described above, and only different points will be described.

In the example of FIG. 6A, the seal portion 30 is formed with a pair of lip portions 3 1 and 3 1, and a grease reservoir portion 3 2 is formed between the pair of lip portions 3 1 and 3 1. It is formed. This grease reservoir 3 2 can improve waterproofness, and can reduce wear caused by the lip portions 31 and 31 when a large peristaltic load is required.

In the example of FIG. 6B, a metal ring 33 is embedded in the seal part 30. By providing the metal ring 33, the followability to the inclination of the male shaft 11 can be increased and the sealing performance can be improved.

In the example of FIG. 7A, the solid lubricant film SLM is coated on the seal surface of the seal part 30 on which the lip parts 31, 31 and 31 are formed. Thereby, wear of the lip portions 31 can be reduced, and sliding resistance can be reduced when the male shaft 11 and the lip portion 31 slide.

In the example of FIG. 7B, the solid lubricating film S L M is coated on the outer peripheral surface of the male shaft 11. As a result, wear of the lip portions 31, 31, and 31 can be reduced, and sliding resistance can be reduced when the male shaft 11 and the lip portion 31 are slid.

(Fifth embodiment)

FIG. 8A is a longitudinal sectional view of a telescopic shaft for vehicle steering according to a fifth embodiment of the present invention, and FIGS. 8B and 8C are enlarged sectional views of the seal member shown in FIG. 8A, respectively. It is.

The basic structure of this embodiment is the same as that of the second embodiment described above, and only different points will be described.

In the example of FIG. 8B, the seal portion 30 has a resin ring 34 that is exposed to the seal surface and adjacent to the lip portion 31.

This resin ring 3 4 has low friction and excellent wear resistance such as dry bearings. It is. Thereby, the followability to the inclination of the male shaft 11 can be increased, and the sealing performance can be improved. Further, since the lip portion 3 1 only needs to bear the gap between the resin ring 3 4 and the male shaft 11 1, the friction caused by the lip portion 3 1 can be minimized.

In the example of FIG. 8C, a metal ring 3 3 is embedded in the seal portion 30, and a resin ring 3 4 is press-fitted into the metal ring 33. As a result, the followability to the inclination of the male shaft 11 can be increased and the sealing performance can be improved.

(Sixth embodiment)

FIG. 9A is a longitudinal sectional view of a telescopic shaft for vehicle steering according to a sixth embodiment of the present invention, and FIG. 9B and FIG. 9C are enlarged sectional views of the seal member shown in FIG. 9A, respectively. It is.

In the example of FIG. 9B, the metal ring 3 3 is embedded in the seal part 30, and the resin ring 35 having the lip parts 3 5a and 3 5a is press-fitted into the metal ring 3 3. . This resin ring 35 is a resin such as an elastomer material.

In the example of FIG. 9C, a metal ring 3 3 is embedded in the seal part 30, and an elastic ring 36 having lip parts 3 6a and 3 6a is fixed to the metal ring 3 3. . This elastic ring 36 is made of rubber with high hardness.

(Seventh embodiment)

FIGS. 11A and 11B are also longitudinal sectional views of the telescopic shaft for vehicle steering according to the seventh embodiment of the present invention.

The basic structure of this embodiment is the same as that of the second embodiment described above, and only different points will be described. In the present embodiment, the fitting portion of the male shaft 11 with the female shaft 10 is enlarged in diameter to form a stepped portion 11a.

Fig. 1 OA is a basic set state, and the seal part 30 is located at a distance A from the step part 1 1 a of the male shaft 11 1. Fig. 10B shows a state where both shafts 10, 11 are extended by a minute distance (1), and Fig. 10C shows a state where both shafts 10, 11 are contracted by a minute distance (1). The seal portion 30 is a force at distances B and C from the step portion 11a. In FIGS. 10A, 10B, and 10C, ABC is a small displacement. In other words, the distance from the stepped portion 1 1 a to the seal 30 does not change much at the minute displacement (1).

Fig. 11A shows a state in which both shafts 10 and 11 are greatly extended from each other by a distance (L), and Fig. 11B shows a state in which both shafts 10 and 11 are contracted from each other by a distance (L). . Where 1 <L.

Referring to FIGS. 10A, 10B, and 10C, the relationship between the axial displacement resistance of the bellows-shaped portion 20 and the sliding resistance of the seal portion 30 is as follows. The resistance is set to be smaller than the sliding resistance of the seal portion 30. As a result, at the time of slight displacement, the bellows-like portion 20 bends and the seal portion 30 becomes difficult to slide on the shaft 11.

On the other hand, the sliding resistance of the seal part 30 is set to be smaller than the axial displacement resistance of the bellows-like part 20 when it becomes larger than that at the time of slight displacement. As a result, at a large displacement (L) as shown in FIG. 11A and FIG. 11 B, the bellows-like portion 20 bends and the seal portion 30 slides on the shaft 11.

The inflection point between the axial displacement resistance of the bellows-like part 20 and the sliding resistance of the seal part 30 is set to be less than the maximum relative displacement (about ± 2.5 mm) during actual vehicle travel. In other words, when a slight displacement occurs during normal vehicle travel, the axial displacement resistance of the bellows-shaped part 20 is smaller than the sliding resistance of the seal part 30, and if a large displacement such as a collision occurs, the sliding resistance of the seal part 30 Is smaller than the axial displacement resistance of the bellows-like portion 20. Further, as shown in FIG. 1, the female shaft 10 is set on the upper side of the vehicle, and the male shaft 11 is set on the lower side of the vehicle. As a result, it is possible to effectively prevent water and the like from entering the intermediate shaft 5.

As a result, even in rainy weather, both the prevention of water intrusion into both shafts 10 and 11, securing a large amount of slide during assembly, and a slight relative displacement during travel are achieved with a slight sliding resistance. It becomes possible.

Therefore, as a result of restraining to a slight sliding resistance, vibration during actual vehicle travel can be suppressed, and comfortable steering performance can be obtained.

In addition, by setting the female shaft 10 to be on the upper side of the vehicle and the male shaft 11 to be on the lower side of the vehicle, even if water enters the internal space of the seal member S, Drops collect near the seal 30. In the length of the subsequent set position, the inside of the seal member S is in the set position after sucking in air and water, so the internal space of the bellows-like part 20 is in a pressurized state. The water droplets collected in the vicinity of the seal portion 30 are gradually discharged to the outside at first.

That is, as shown in FIG. 11A, when both shafts 10 and 11 are greatly extended from each other, the internal space of the bellows-shaped portion 20 becomes negative pressure while the seal portion 30 is Sliding on 1 1, the distance from step 1 1 a is at position D. Fig. 1 O <D for the distance A in the set state shown in A A, and the seal 30 is sliding with respect to the shaft 11.

-On the other hand, as shown in Fig. 11 B, when both shafts 10 0 and 11 are greatly contracted with each other, the internal space of the bellows-like portion 20 becomes positive pressure (ie, pressurizing), and the seal The part 30 slides on the shaft 11 and comes into contact with the end of the shaft 10 and stops. At this time, the distance between the seal part 30 and the step part 11a is E. Fig. 1 O A <E with respect to distance A in the set state shown in A A, and the seal slides with respect to shaft 11.

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

Claims

The scope of the claims

1. A telescopic shaft for vehicle steering that is built into the steering shaft of a vehicle and has a male shaft and a female shaft that are non-rotatable and slidably fitted.

The telescopic shaft is

When the steering torque exceeds a predetermined value, there is a rigid torque transmission part that transmits the operation torque between the two shafts by a rigid hornworm,

One end is fixed to the male shaft, the fitting portion of the male shaft and the two shafts is covered, and an axially expandable / contractible bellows-shaped dustproof boot having the other end fixed to the female shaft is provided. Telescopic shaft for vehicle steering.

2. The preload torque transmission part is

Between the outer circumferential surface of the male shaft and the inner circumferential surface of the female shaft, the first torque transmission member is interposed between at least one row of axial grooves formed through the elastic body,

The rigid torque transmission part is

The second torque transmission member is interposed between at least one other groove direction formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft, respectively. Telescopic shaft for vehicle steering as described.

3. The first torque transmission member is a rolling element that rolls in the axial relative movement of the two shafts,

3. The vehicle steering telescopic shaft according to claim 2, wherein the second torque transmitting member is a moving body that slides when the both wheels move in the axial direction relative to each other.

4. The rigid torque transmitting part is

Provided on the outer peripheral portion of the male shaft and the inner peripheral portion of the female shaft, respectively, and in contact with each other during rotation, torque is transmitted;

The preload torque transmission unit is

Provided between the outer periphery of the male shaft and the inner periphery of the female shaft at a position different from the rigid torque transmitting portion, and rolls when the male shaft and the female shaft move in the axial direction. The rolling element according to claim 1, and an elastic body that is disposed adjacent to the rolling element in a radial direction and applies a preload to the male shaft and the female shaft via the rolling element. The telescopic shaft for vehicle steering described in 1.

5. Built into the vehicle steering shaft, the male and female shafts are non-rotatable and slidably fitted,

In the telescopic shaft for vehicle steering, which is fitted with a seal member that seals the fitting portion of both shafts and prevents rainwater and the like from entering the fitting portion.

The sealing member is

A telescopic shaft for vehicle steering, comprising: a seal portion that is formed at one end of the bellows-like portion and that makes contact with an outer peripheral surface of either of the two shafts with an appropriate fastening margin.

6. The other end of the bellows-like portion is fixed to the outer peripheral surface of the female shaft,

6. The vehicle steering telescopic shaft according to claim 5, wherein the seal portion is in contact with an outer peripheral surface of the male shaft with an appropriate tightening allowance.

7. The vehicle steering extension according to claim 5 or 6, wherein the seal portion has a pair of lip portions between which a grease reservoir portion is formed. Reduced axis.

8. The telescopic shaft for vehicle steering according to claim 5 or 6, wherein the seal portion has a metal ring embedded therein.

9. The telescopic shaft for vehicle steering according to claim 5 or 6, wherein the lip portion of the seal portion is coated with a solid lubricating film.

10. The telescopic shaft for vehicle steering according to claim 5 or 6, wherein a solid lubricating film is coated on an outer peripheral surface of the male shaft that is in contact with the seal portion.

11. The telescopic shaft for vehicle steering according to claim 5 or 6, wherein the seal portion has a resin ring exposed to the seal surface and adjacent to the lip portion.

The seal part has a metal ring embedded therein, and a resin ring exposed to the seal surface and adjacent to the lip part and press-fitted into the metal ring. The telescopic shaft for vehicle steering as described in 6.

1 3. The seal portion has a metal ring embedded therein, and a resin ring or an elastic ring exposed to the seal surface and press-fitted or fixed to the metal ring. The telescopic shaft for vehicle steering according to claim 5 or 6.

14. The relationship between the axial displacement resistance of the bellows-like portion and the sliding resistance of the seal portion is that the axial displacement resistance of the bellows-like portion is less than the sliding resistance of the seal portion when there is a slight displacement. Smaller,

The telescopic shaft for vehicle steering according to claim 5 or 6, wherein the telescopic shaft for vehicle steering is set as follows.

1 5. When the two shafts are greatly extended, the internal space of the bellows-shaped part is negative, while the seal part slides,

15. The vehicle steering telescopic shaft according to claim 14, wherein when the two shafts contract greatly, the inner space of the bellows-like portion is positive pressure and the seal portion slides. .