JP2005003049A - Axial expansion boot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an axial expansion boot (a rack boot) easy of mounting work. <P>SOLUTION: The axial expansion boot (the rack boot) to be expansively mounted on a steering unit or the like in the axial direction comprises a bellows portion 15 formed of a polymer forming material between a first ring portion 11 and a second ring portion 13. A male screw portion 15 is provided on at least one of the first ring portion 11 and the second ring portion 13, and fastening nuts 25, 25' are provided for taper/parallel threading to the male screw portion. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
【Technical field】
The present invention relates to an axially stretchable boot that is formed of a polymer molding material, and is provided with a bellows portion between a first ring portion and a second ring portion so as to be stretchable in the axial direction. In particular, the present invention relates to an invention suitable for a steering rack boot (hereinafter referred to as “rack boot”) in an automobile. Here, a rack boot that protects the steering unit from dust or the like will be described as an example, but the present invention is also applicable to other dust boots that expand and contract in the axial direction.
[0002]
[Background]
As shown in FIG. 1, the rack boot 10 is a protective member for the steering unit 16 in which a bellows portion 15 is formed between a large-diameter ring portion (first ring portion) 11 and a small-diameter ring portion (second ring portion) 13. is there. Usually formed of a polymer material, the large-diameter ring portion 11 is fitted to the unit case 17 of the steering unit 16 and the small-diameter ring portion 13 is fitted to the tie rod 19 so as to expand and contract in the axial direction. Installed and used as possible. Thus, the rack boot 10 plays a role of protecting the steering unit 16 from dust, rainwater, stepping stones and the like.
[0003]
On the other hand, the steering unit 16 is arranged in the immediate vicinity of the suspension device and the transmission in the engine room. For this reason, the rack boot 10 is deteriorated and damaged by radiant heat from the exhaust pipe, ozone, ultraviolet rays, rainwater, stepping stones, etc., and needs to be replaced periodically.
[0004]
The rack boot 10 replacement work needs to be performed in an extremely narrow space in the engine room, unlike the automobile assembly. For this reason, when fastening the large diameter ring part 11 with respect to the unit case 17 located in the back | inner side especially, the difficulty has arisen in the fastening operation | work using a general purpose fastening band. For example, in the buckle type fastening band 21, it is very difficult to insert the hand into the narrow part and to tilt the buckle 23.
[0005]
In addition, as a prior patent document regarding a rack boot, although not affecting the inventiveness of the present invention, there are the following patent documents 1 and 2 and the like.
[0006]
[Patent Document 1]
JP-A-6-307545 [Patent Document 2]
Japanese Patent Laid-Open No. 10-238629
DISCLOSURE OF THE INVENTION
[0008]
[Problems to be solved by the invention]
In view of the above, it is an object of the present invention to provide an axially stretchable boot that facilitates the work of fastening the first and second ring portions of the rack boot to the steering unit, that is, the work of attaching the rack boot.
[0009]
[Means for Solving the Problems]
The present invention solves the above object (problem) by the following configuration.
[0010]
The axially stretchable boot of the present invention is formed of a polymer molding material, and is attached between the first ring part and the second ring part as a bellows part so as to be stretchable in the axial direction. At least one of the ring part and the second ring part is provided with a male screw part, and a fastening nut for screwing a taper screw / parallel screw into the male screw part is provided. By using the axially stretchable boot provided with the fastening nut, the mounting workability is significantly improved as compared with the axially stretchable boot that has to be fastened using a conventional fastening band or the like.
[0011]
That is, the rack boot (axially stretchable boot) of the present invention does not require any tools. The rack boot can be fixed as long as there is a space where the operator's hand can be inserted, and the mounting workability is very good.
[0012]
In the above-described configuration, the locking projection is provided with a stopper recess on the first ring portion and / or the second ring portion side, and is elastically engaged at the fastening completion position of the fastening nut so as to correspond to the stopper recess on the fastening nut side. It is desirable to have a structure with Loosening of the fastening nut after the fastening work can be prevented.
[0013]
Moreover, in the said structure, it can also be set as the split type in which a pair of division part was formed linearly from the 1st ring part to the said 2nd ring part. When the split type is used, the workability of attaching the axially stretchable boot is further improved.
[0014]
That is, the split type boot can be attached so that the half boot is sandwiched between the both sides of the mounting part, so that the mounting part is not required to be disassembled during replacement, and the mounting workability of the axially stretchable boot is further improved. Further, since the mounting portion is not disassembled, alignment adjustment after the rack boot replacement operation is not necessary.
[0015]
In the split-type axially stretchable boot, the flap and the flap receiving concave surface are formed between the split portions of the inner surfaces of the first ring portion and the second ring portion, which can improve the shape retention and sealing performance. it can.
[0016]
Further, in the above configuration, the fact that the fastening nut is a halved type that can be divided and combined contributes to an improvement in mounting workability.
[0017]
As the above-mentioned halved type fastening nut, it is possible to divide and connect the fastening nut easily by the snap protrusion and the snap recessed portion.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The axially stretchable boot of the present invention is not limited to this configuration, and can be appropriately changed in design without departing from the gist of the present invention. In addition, about the same part as a prior art example, the same figure code | symbol is attached | subjected and all or one part of those description is abbreviate | omitted.
[0019]
2A to 5 show a rack boot (axially stretchable boot) 10A which is an embodiment according to the present invention.
[0020]
The rack boot 10A of the present embodiment is formed of a polymer molding material, and a space between the first ring portion 11 and the second ring portion 13 is a bellows portion 15 and is mounted so as to be expandable and contractable in the axial direction. . The configuration so far is the same as that of the conventional rack boot.
[0021]
The polymer molding material constituting the rack boot 10A may be any material as long as it can function as a rack boot, but may be a thermoplastic elastomer (for example, polyester TPE) or the like. Hard plastic (preferable specific material) etc. can be used conveniently. Using these materials, rack boots are molded by injection molding or blow molding.
[0022]
The rack boot 10A according to the present invention includes male screw portions 23 and 23 'on at least one of the first ring portion 11 and the second ring portion 13 (both in FIGS. 2 and 3), and the male screw portions 23 and 23. Fastening nuts 25 and 25 ′, which are screwed into a taper screw / parallel screw, are respectively provided on ′. In the illustrated example, the male screw portions 23 and 23 'side is a tapered male screw (original portion side large diameter), and the fastening nuts 25 and 25' side is a parallel female screw. Naturally, the male screw portion side may be a parallel screw, and the nut side may be a taper female screw (screwed tip side large diameter).
[0023]
By making the rack boot provided with the fastening nuts 25 and 25 'to be screwed into the taper screw / parallel screw, the ring portion (male screw portion) is subjected to a diameter reducing action as the screw is screwed. Therefore, the rack boot 10A according to the present embodiment can fasten the ring portions 11 and 13 by screw type fixing to the steering unit. As will be described later, this configuration significantly improves the mounting workability as compared with the rack boot 10 in which the fastening work must be performed using the conventional fastening band 21 or the like.
[0024]
As the type of the threaded portion, a single thread may be used in the illustrated example, but a multiple thread such as a double thread may be used. In the case of a double thread, a large lead (distance that advances in the axial direction when the screw is rotated once) can be obtained with a small amount of rotation. Moreover, any of a triangular screw, a square screw, a trapezoidal screw, and a sawtooth screw can be used.
[0025]
The fastening nuts 25 and 25 'may be formed of the same material as the main body of the rack boot 10A, or may be formed using another material (for example, polyamide, polyacetal, etc.). Further, in the present embodiment, as shown in FIG. 3, a stopper recess 29 is provided on the first ring portion 11 and the second ring portion 13 side, and a fastening nut 25 corresponding to the stopper recess 29 on the fastening nuts 25, 25 ′ side. , 25 ′, a lock protrusion 31 that is elastically engaged at a fastening completion position is provided.
[0026]
In FIG. 3, a first stopper piece is provided by providing an introduction check piece (first sputter piece) 33 and a locking piece (second stopper piece) 34 on the first ring portion 11 and the second ring portion 13 side, respectively. A stopper recess 29 is formed between the second stopper piece 34 and the second stopper piece 34. The first stopper piece 33 has a substantially right-angled cross section with the outer side inclined with respect to the stopper recess 29 so that the lock projection 31 is smoothly introduced into the stopper recess 29.
[0027]
Immediately before completion of fastening by the fastening nuts 25, 25 ′, the lock protrusion 31 provided on the fastening nuts 25, 25 ′ approaches the stopper recess 29 from the first stopper piece 33 side. The lock protrusion 31 is introduced into the stopper recess 29 while moving along the inclined portion of the first stopper piece 33 and engages spring-elastically. After the fastening operation, the first stopper piece 33 and the second stopper piece 34 exist on both sides of the lock projection 31. Therefore, the lock projection 31 is sandwiched between the side walls, and the fastening nuts 25, 25 ' Inhibits rotation. Therefore, the fastening nut is prevented from loosening.
[0028]
The fastening nuts 25 and 25 'may be of a split type as shown in FIG.
[0029]
Next, based on FIGS. 4-5, the mounting | wearing aspect of 10 A of rack boots which are a non-split type is demonstrated.
[0030]
Since the rack boot 10A is a non-split type, it is necessary to disassemble the tie rod 19 end (tie rod end) in the steering unit 16. First, after removing the tie rod end from the steering unit 16, the rack boot 10 </ b> A is inserted into the mounting portion of the steering unit 16 so that the first ring portion 11 side is located on the back side.
[0031]
Next, the rack boot 10A is fastened. The fastening operation is performed by screw fixing using a fastening nut. First, the fastening nut 25 is manually rotated and moved to the fastening completion position of the first ring portion 11. When the fastening completion position is reached, the lock projection 31 is smoothly introduced into the stopper recess 29 and engaged spring-elastically. Thus, the first ring portion 11 is fastened to the unit case 17 of the steering unit 16.
[0032]
Then, the other fastening nut 25 ′ is also manually rotated and moved to the fastening completion position of the second ring portion 13 as described above. When the fastening completion position is reached, the lock projection 31 is smoothly introduced into the stopper recess 29 and engaged spring-elastically. Thus, the second ring portion 13 is fastened to the tie rod 19 of the steering unit 16.
[0033]
In the above fastening, both are configured to be screwed into a taper screw / parallel screw, so that when the fastening nuts 25 and 25 ′ are tightened, the ring portions 11 and 13 are connected via the male screw portions 23 and 23 ′. The diameter is reduced. Thus, the fastening is completed between the steering unit 16 and the ring portions 11 and 13 of the rack boot 10A, and the necessary fastening strength (sealability) can be ensured.
[0034]
Finally, the tie rod end is reassembled to the steering unit 16 and the alignment of the steering unit 16 is adjusted to complete the mounting operation.
[0035]
6 to 10 show a rack boot 10B which is another embodiment according to the present invention.
[0036]
The present embodiment can be a split type in which a pair of divided portions 36 and 36 ′ are formed linearly from the first ring portion 11 to the second ring portion 13. FIG. 4 shows a half-boot 38 on one side when the split-type rack boot 10B is divided, and the rack shown in FIG. 10 is combined with the other half-boot 38 ′ having a symmetrical shape (not shown). It can be set as the boot 10B.
[0037]
In the split-type rack boot 10B of this embodiment, a flap 40 and a flap receiving concave surface 42 are formed between the divided portions of the inner surfaces of the first ring portion 11 and the second ring portion 13 (see FIG. 6). This is to ensure shape retention and airtightness (sealability).
[0038]
A side view when the half boots 38, 38 'are combined is shown in FIG. The coupling between the half boots 38 and 38 'is performed by using the fastening nuts 25A and 25A' combined with the half nuts 44 in the divided portions 36 and 36 'in the first ring portion 11 and the second ring portion 13. Just conclude. On the other hand, in the divided parts 36 and 36 ′ in the bellows part 15, a known split type rack boot coupling mode can be suitably applied.
[0039]
As a specific example, for example, as shown in FIG. 7, a seal fastener structure having the following configuration previously filed by the present applicants (see Japanese Patent No. 2714635, Japanese Patent Publication No. 5-50921, etc.) can be suitably used. .
[0040]
“A belt-shaped occlusal ridge 54 formed along the edge of one divided portion and having a bulging engagement portion 52 at the tip, and a rubber-like elastic body formed along the edge of the other divided portion. And a structure comprising a band-like portion 58 to be occluded provided with an occlusal groove 56 to be engaged with the occlusal ridge 54 ”
The thickness of the general portion of the occlusal ridge 54 is configured to be smaller than the gap between the open ends of the occlusal groove 56. The occlusal ridge portion 54 is made of a linear spring material, and a sandwiched insert (shown in the back view) having a corrugated plane is embedded, and the occlusal ridge portion 54 is given rigidity in the occlusal direction.
[0041]
On the outer peripheral portion of the occlusal groove 56, a sandwich insert made of a linear spring material and having a transverse shape having substantially no corners is embedded, and the spring is sandwiched between the open end portions of the occluded portion 58. Power is granted. As the shape of the sandwiching insert, it is possible to use a shape in which a linear material is alternately bent in a staggered manner to form a groove-like space having an opening side taper. When this corner is not substantially provided, bending fatigue does not occur in the spring material with repeated use, and a good clamping force can be maintained over a long period of time. Therefore, it contributes to the improvement of the durability of the fastener. These insert materials are not limited to metal, and may be hard plastic as long as a predetermined spring force can be applied.
[0042]
The fastening nuts 25 and 25 'for fastening the split type rack boot 10B are of a split type that can be divided and combined.
[0043]
FIG. 8 shows the half nuts 44 and 44 ′ when the fastening nut 25 for the split type large-diameter ring portion 11 is divided. By combining them, the fastening nut 25 </ b> A can be obtained. The same applies to the fastening nut 25 ′ for the other small-diameter ring portion 13.
[0044]
Each half nut 44, 44 ′ can be divided and coupled to each other by a snap projection 46 and a snap recess 48. With this configuration, division and coupling can be easily performed. For the connection, the snap projection 46 of one half nut may be fitted into the snap recess 48 of the other half nut.
[0045]
Next, a mounting mode of the split type rack boot 10B will be described with reference to FIGS.
[0046]
In the following description, the rack boot having the above-described seal fastener structure previously proposed by the present inventors will be described as an example. In the case of the split-type rack boot, the boot unit can be mounted not by inserting the boot into the mounting part but sandwiching the mounting part from both sides.
[0047]
That is, in a state where the first ring portion 11 is located on the back side of the mounting part, half nuts (large diameter side) 44, 44 ', half boots 38, 38', half nut (small diameter side) 44a , 44a ′ are assembled so as to be sandwiched between the steering units 16.
[0048]
In the half boots 38 and 38 ′, the first ring portion is inserted into the occlusal groove 56 of the occlusal portion 58 while grasping the occlusal convex portion 54 of the divided portions 36 and 36 ′ by hand from the half state shown in FIG. From the 11th side or the second ring part 13 side, the occlusal convex part 54 is pushed into the occluded part 58 in sequence, and is engaged. The bulging and engaging portion 52 of the occlusal protruding portion 54 is forcibly expanded between the open end portions of the occlusal groove 56 of the occluded portion 58 and is engaged with the keyhole-shaped occlusal groove 56. At this time, since the sandwiched insert is embedded in the occlusal ridge 54 and the rigidity in the insertion direction is given, the occlusion workability is good. In addition, between the open end portions of the occlusal groove 56, a spring force is applied in the closing direction by the sandwiching insert and the occlusal portion 58 is formed of a rubber-like elastic body. The general portion 54 is sandwiched between the open end portions of the occlusal groove 56 in a close state, and a sealing function is imparted to the occlusal portion, and a large retaining force is generated.
[0049]
At this time, it is desirable to perform the occlusion work by applying silicone oil to one or both of the occlusal convex part 54 and the occluded part 58 because the occlusion workability and the sealing performance of the occlusal part are improved.
[0050]
In the half nuts (large diameter side) 44, 44 'and the half nuts (small diameter side) 44A, 44A', the snap projection 46 of one half nut is fitted into the snap recess 48 of the other half nut. Therefore, the fastening nuts 25 and 25 'are set.
[0051]
The subsequent steps are the same as the fastening method in the case of the non-split type described in FIGS. 4 and 5, and the fastening nuts (44, 44 ′) are rotated by hand and moved to the fastening completion position of the first ring portion 11. The other fastening nut (44a, 44a ') is also rotated by hand and moved to the fastening completion position of the second ring portion 13 in the same manner as described above. When the fastening completion position is reached, the lock projection 31 is smoothly introduced into the stopper recess 29 and engaged spring-elastically. Thus, the first ring portion 11 is fastened to the unit case 17 of the steering unit 16 and the second ring portion 13 is fastened to the tie rod 19 of the steering unit 16.
[0052]
In the above fastening, as in the case described above, since the taper screw / parallel screw screwing is employed, the fastening of the fastening nuts 25 and 25 'causes the ring parts 11 and 13 to be male threaded parts 23 and 23, respectively. The diameter is reduced through a '. Thus, the fastening is completed between the steering unit 16 and the ring portions 11 and 13 of the rack boot 10A, and the necessary fastening strength (sealability) can be ensured.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a mounting manner of a conventional rack boot.
FIG. 2 is a cross-sectional view and an enlarged partial cross-sectional view of a portion A and a portion B (cross-sectional hatch omitted) in an embodiment when the present invention is applied to a non-dividing type rack boot.
FIG. 3 is a perspective view and a side view of a rack boot in the same embodiment.
FIG. 4 is a perspective view showing a rack boot mounting mode start time in the same embodiment;
FIG. 5 is a perspective view showing when the mounting mode is completed.
FIG. 6 is a perspective view of a half boot forming a rack boot in one embodiment when applied to a split type rack boot of the present invention.
FIG. 7 is a front view showing a rack boot in the embodiment.
FIG. 8 is a perspective view of a half ring used when fastening the rack boot in the embodiment.
FIG. 9 is a perspective view showing a mounting mode start time in the embodiment.
FIG. 10 is a perspective view showing when the mounting mode is completed.
[Explanation of symbols]
10, 10A, 10B Rack boot 11 Large-diameter ring part (first ring part)
13 Small diameter ring part (second ring part)
15 Bellows 23, 23 'Male thread 25, 25' Fastening nut 27, 27 'Female thread 29 Stopper recess 31 Lock projection 36, 36' Split part

Claims (7)

In an axially stretchable boot that is formed of a polymer molding material and that is a bellows part between the first ring part and the second ring part and is mounted so as to be stretchable in the axial direction.
An axially stretchable boot comprising: a male screw portion provided on at least one of the first ring portion and the second ring portion; and a fastening nut that engages the male screw portion with a taper screw / parallel screw. A locking protrusion that is provided with a stopper recess on the first ring portion and / or the second ring portion side, and that elastically engages with the stopper recess on the fastening nut side at a fastening completion position of the fastening nut. The axially stretchable boot according to claim 1, further comprising: 3. The axially stretchable boot according to claim 1, wherein the axially stretchable boot is a split type in which a pair of split portions are linearly formed from the first ring portion to the second ring portion. 4. The axially stretchable boot according to claim 3, wherein a flap and a flap receiving concave surface are formed between divided portions of the inner surfaces of the first ring portion and the second ring portion. The axially stretchable boot according to claim 3 or 4, wherein the fastening nut is a half type that can be divided and coupled. The axially stretchable boot according to claim 5, wherein the half-type fastening nut can be divided and joined by a snap protrusion and a snap recess. A steering rack boot comprising the configuration according to claim 1.

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