JP2008168890A - Telescopic shaft for vehicle steering mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a telescopic shaft for a vehicle steering mechanism that improves anti-creep property and generates less rattle, and whose processing cost is low. <P>SOLUTION: This telescopic shaft for the vehicle steering mechanism, which is assembled into the steering mechanism of a vehicle, includes a male shaft 21 and a female shaft, which are fitted to each other in such a way that they may not be rotated but slidable. In this telescopic shaft, a resin layer 23 made of a synthetic resin composite containing a filler of 5-50 weight percent is provided on the outside circumference of the male shaft 21. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

    The present invention relates to a telescopic shaft for vehicle steering that is incorporated in a steering mechanism portion of a vehicle and has a male shaft and a female shaft fitted in a non-rotatable and slidable manner.

  FIG. 7 shows a general automobile steering mechanism 15. The steering mechanism 15 includes a steering column 4 attached to a member 1 on the vehicle body side via an upper bracket 2 and a lower bracket 3, a steering shaft 5 rotatably supported on the steering column 4, and the steering A steering wheel 6 mounted on the upper end of the shaft 5, an intermediate shaft 8 connected to the lower end of the steering shaft 5 via a cardan shaft joint 7, and a cardan shaft joint 9 connected to the intermediate shaft 8. A coupled pinion shaft 10, a steering rack shaft 11 coupled to the pinion shaft 10, and a steering rack support member 14 that supports the steering rack shaft 11 and is fixed to another frame 12 of the vehicle body via an elastic body 13. It consists of and.

The intermediate shaft 8 employs a telescopic shaft in which a male spline shaft 8a and a female spline shaft 8b are fitted (hereinafter referred to as a telescopic shaft 8). The telescopic shaft 8 is required to absorb the axial displacement generated when the automobile travels, and to transmit the displacement and vibration on the steering wheel 6.
In such a performance, the vehicle body has a sub-frame structure, and the member 1 that fixes the upper part of the steering mechanism 15 and the frame 12 to which the steering rack support member 14 is fixed are separated from each other. This is required in the case of a structure in which the rack support member 14 is fastened and fixed to the frame 12 via an elastic body 13 such as rubber.

As another case, when the cardan shaft joint 9 is fastened to the pinion shaft 10, an extension function is required for the operator to contract the telescopic shaft 8 once and then fit it to the pinion shaft 10 to fasten it. The
Further, the steering shaft 5 at the upper part of the steering mechanism section 15 is also formed by fitting the male spline shaft 5a and the female spline shaft 5b (hereinafter referred to as the telescopic shaft 5). The telescopic shaft 5 is required to have a telescopic function that moves the position of the steering wheel 6 in the axial direction and adjusts the position in order to ensure an optimal driving posture for the driver to drive the automobile. A function to expand and contract in the direction is required.

Here, the telescopic shafts 5 and 8 can reduce the rattling noise at the fitting portions of the male shaft splines 5a and 8a and the female spline shafts 5b and 8b, reduce the rattling on the steering wheel 6, and It is required to reduce the sliding resistance when sliding in the axial direction.
Therefore, as in Patent Document 1, for example, the nylon spline shafts 5a and 8a of the telescopic shafts 5 and 8 are coated with a nylon film, and grease is applied to the sliding portion, so that metal noise, metal hitting sound, etc. While absorbing or mitigating, the sliding resistance has been reduced and the play in the rotational direction has been reduced. In this case, as a process of forming the nylon film, the shaft is washed → primer applied → heated → nylon powder coating → rough cutting → finish cutting → selective fitting with a male spline shaft. The final cutting is performed by selecting a die in accordance with the machining accuracy of the already processed male spline shaft.
JP 2006-123820 A

However, as described above, the telescopic shaft formed with the nylon film has a problem that the processing cost becomes very high in order to finish the final finish cutting with high accuracy.
In addition, because non-reinforced nylon is used as the material for the membrane, sag (creep) gradually occurs, and minute backlash may occur between the male spline shaft and the female spline shaft. .

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a vehicle steering telescopic shaft that has improved creep resistance and low backlash and has a low processing cost.

To achieve the above object, a telescopic shaft for vehicle steering according to claim 1 is incorporated in a steering mechanism portion of a vehicle, and a telescopic shaft for vehicle steering in which a male shaft and a female shaft are non-rotatably and slidably fitted. The resin layer which consists of a synthetic resin composition containing 5-50 wt% of fillers was provided between the male shaft and the female shaft.
According to a second aspect of the present invention, in the telescopic shaft for vehicle steering according to the first aspect, the filler has a Mohs hardness of 4.5 or less.

According to a third aspect of the present invention, in the telescopic shaft for vehicle steering according to the first or second aspect, the thickness of the resin layer is set in the range of 100 to 2000 μm.
The invention according to claim 4 is the telescopic shaft for vehicle steering according to any one of claims 1 to 3, wherein the filler is potassium titanate whisker, zinc oxide whisker, basic magnesium sulfate, sepiolite, At least one selected from calcium carbonate whisker and wollastonite was used.

  According to a fifth aspect of the present invention, in the telescopic shaft for vehicle steering according to any one of the first to third aspects, the base resin containing the filler is a polyphenylene sulfide resin, a polyether ether ketone resin, Polyamide resin such as polyamide 6, polyamide 66, polyamide 46, polyamide 12, polyamide 11, modified polyamide 6T, polyamide 9T, polyamide MXD6, polyvinylidene fluoride, ethylene tetrafluoride-ethylene copolymer, ethylene tetrafluoride-6 It was set as the synthetic resin which has heat resistance consisting of fluororesins, such as a fluorinated propylene copolymer and a tetrafluoroethylene-perfluoro vinyl ether copolymer.

According to a sixth aspect of the present invention, in the telescopic shaft for vehicle steering according to the fifth aspect, the water absorption after the base resin containing the filler is allowed to stand for 24 hours in a 23 ° C. temperature environment is 0. 1 wt% or less of resin is used.
Also. A seventh aspect of the present invention is the vehicle steering telescopic shaft according to any one of the first to sixth aspects, wherein the resin layer is a resin sleeve provided on an outer periphery of the male shaft.

  The invention according to claim 8 is the telescopic shaft for vehicle steering according to any one of claims 1 to 6, wherein the resin layer is a resin film provided on the inner periphery of the female shaft.

  According to the telescopic shaft for vehicle steering according to the present invention, it is possible to obtain a low-cost telescopic shaft for vehicle steering that has excellent creep resistance, does not generate backlash, and has improved sliding stability.

Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the component same as the structure shown in FIG. 7, and the description is abbreviate | omitted.
FIG. 1 is an exploded perspective view of a telescopic shaft for vehicle steering (hereinafter referred to as a telescopic shaft) according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of a male spline shaft of the telescopic shaft of the first embodiment. .

As shown in FIG. 1, the telescopic shaft 20 of this embodiment includes a male spline shaft 21 and a female spline shaft 22 that are spline-fitted with each other.
As shown in FIG. 2, a resin sleeve 23 is fitted on the outer peripheral surface of the male spline shaft 21. The resin sleeve 23 may be fixed by press-fitting into the male spline shaft 21 after injection molding as a separate body, or may be formed by insert molding with the male spline shaft 21 as a core.

  The thickness of the resin sleeve 23 is set in the range of 100 to 2000 μm. When the thickness of the resin sleeve 23 is less than 100 μm, it is difficult to secure a certain strength or more, and there is a possibility that cracks or the like may occur during use. On the other hand, when the thickness of the resin sleeve 23 exceeds 2000 μm, the difference in linear expansion coefficient with the female spline shaft 22 may increase when the temperature rises, and the play may increase.

  The resin material of the resin sleeve 23 is set so as to contain 5 to 50 wt% (more preferably 15 to 40 wt%) of a filler having a Mohs hardness of 4.5 or less based on the total amount of the synthetic resin composition. ing. When the filler content is less than 5 wt%, the creep resistance is lowered. When the filler content exceeds 50 wt%, the creep resistance is improved, but the fluidity during molding is deteriorated. It becomes difficult to mold the resin sleeve 23 with a uniform thickness.

Considering the adhesiveness of the resin sleeve 23 to the resin material, if the filler is subjected to surface treatment such as a silane coupling agent, the strength of the resin sleeve 23 as a whole is improved.
As the filler having a Mohs hardness of 4.5 or less, as shown in Table 1, a needle-shaped material having a Mohs hardness is used. Specifically, potassium titanate whisker, zinc oxide whisker (tetrapot shape), basic magnesium sulfate, sepiolite, calcium carbonate whisker, wollastonite and the like.

  As shown in Table 1, when the Mohs hardness of the filler is 4.5 or less, the female spline shaft 22 is made of iron (raw material; Mohs hardness 4.5) that has not been hardened such as heat treatment. In particular, it is not necessary to use an iron material that has been hardened, so that the cost can be reduced.

  Further, as the base resin containing the filler shown in Table 1, those having a certain level of heat resistance are preferable. Specifically, polyphenylene sulfide resin, polyether ether ketone resin, polyamide 6, polyamide 66, polyamide 46, polyamide 12, polyamide 11, modified polyamide 6T, polyamide 9T, polyamide MXD6 and other polyamide resins, polyvinylidene fluoride, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, Fluorine resins such as tetrafluoroethylene-perfluorovinyl ether copolymer are used.

Among the above-mentioned base resins containing a filler, polyphenylene sulfide resin, polyether ether ketone resin, polyvinylidene fluoride, tetrafluoroethylene-ethylene having a low water absorption of 0.1 wt% or less after 24 hours at 23 ° C. Fluorine resins such as copolymers and ethylene tetrafluoride-hexafluoropropylene copolymers are more preferred.
Among the above-mentioned fluororesins, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluorovinyl ether copolymer are used for static friction of the resin itself. Since the coefficient is as low as 0.1 or less (against polished steel), the friction coefficient of the entire synthetic resin composition is also low accordingly. Therefore, when used as a base resin of a synthetic resin composition used for the resin sleeve of the present invention, the slidability is improved. The above-mentioned synthetic resin composition further includes various additives such as antioxidants and heat stabilizers, ethylene propylene non-conjugated diene rubber (EPDM), fine particle acrylic rubber to improve impact resistance. Alternatively, a compound containing a rubber-like substance such as fine particle acrylonitrile butadiene rubber may be used.

  Further, when a polyamide resin is used as the base resin containing the filler, if an adhesive layer is provided between the surface of the male spline shaft 21 and the inner peripheral surface of the resin sleeve 23, the dimensional change due to water absorption can be further suppressed. Can do. Here, in order to form the adhesive layer, for example, there is a method in which a silane coupling agent is applied to the surface of the male spline shaft 21 and then the resin sleeve 23 is heat-pressed or subjected to high-frequency heating after insert molding. In the method of performing high-frequency heating, a strong adhesive layer is formed, and at the same time, only the inner peripheral surface (interface) of the resin sleeve 23 adjacent to the surface of the male spline shaft 21 is melted and residual stress generated by press-fitting (insert molding). Can also be removed.

And if the surface temperature of the male spline shaft 21 at the time of high-frequency heating is 200 to 450 ° C., the adhesive strength becomes strong. The heating atmosphere may be air, but if it is performed in an inert gas atmosphere such as argon gas, the oxidative deterioration of the resin or the like can be suppressed.
The silane coupling agent used for adhesion has an alkoxy group which is a hydrolyzable group at one end of its chemical structure, and this alkoxy group is hydrolyzed to change into a hydroxyl group, and this hydroxyl group is a hydroxyl group on the metal surface. As a result of dehydration condensation, a covalent bond with a high bonding strength is formed with the metal. Further, the other end has an organic functional group, and this organic functional group is bonded to an amide bond in the molecular structure of the polyamide resin. And by these coupling | bonding, a core pipe and a resin part are couple | bonded firmly.

  As the organic functional group, an amino group and an epoxy group are suitable. As the silane coupling agent having such an organic functional group, γ-glycidoxypropyltrimethoxysilane, β (3,4-epoxy) (Cyclohexyl) ethyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, and the like. In particular, those having an epoxy group as an organic functional group have high reactivity with an amide bond.

In order to more firmly bond the adhesive layer to the outer peripheral surface of the core tube, it is more preferable to subject the surface of the male spline shaft 21 to surface treatment with oxygen plasma or the like in order to increase surface hydroxyl groups.
In addition, in order to improve the adhesion between the resin sleeve 23 and the male spline shaft 21 and to prevent slipping of the boundary portion of the male spline shaft 21 including an increase in adhesive force, Air blast processing etc. may be given. As the surface roughness of the male spline shaft 21 after air blasting, Ra of about 1.0 to 2.0 is appropriate.

Further, the roughening of the surface of the male spline shaft 21 is preferable because the bondability (adhesion) at the interface portion is improved even when another base resin is used.
Therefore, according to this embodiment, since the resin sleeve 23 containing 5 to 50 wt% filler with respect to the total amount of the synthetic resin composition is fitted to the male spline shaft 21, the telescopic shaft having excellent creep resistance. 20 can be obtained.

In addition, since the Mohs hardness of the filler is 4 or less of the Mohs hardness of iron, even if the female spline shaft 22 is formed of a raw material of iron, wear does not easily occur. Can be achieved.
Moreover, since the low water absorption resin whose water absorption is 0.1 wt% or less is used as the base resin of the synthetic resin composition, the telescopic shaft 20 having improved sliding stability can be obtained even in a high temperature and high humidity environment. Can do.

Further, since the thickness of the resin sleeve 23 is set in the range of 100 to 2000 μm, it is possible to prevent the occurrence of cracks and the like during use, and to ensure a certain strength or more, and the female spline shaft 22 when the temperature rises. The difference between the linear expansion coefficients can be suppressed to prevent backlash.
In the first embodiment of FIGS. 1 and 2, the telescopic shaft 20 in which the resin sleeve 23 is fitted to the outer peripheral surface of the male spline shaft 21 has been described. However, the gist of the present invention is not limited to this. 3, a resin film 24 made of a synthetic resin composition containing 5 to 50 wt% of a filler having a Mohs hardness of 4.5 or less is formed on the inner peripheral surface of the female spline shaft 22. Even when formed with the same conditions as the resin sleeve 23, such as thickness, base resin, and filler, it has excellent creep resistance and improved sliding stability even in a high temperature and high humidity environment, resulting in low cost. The telescopic shaft 20 can be manufactured.

Next, FIG.4 and FIG.5 shows the expansion-contraction axis | shaft of 3rd Embodiment which concerns on this invention.
FIG. 4 is a transverse sectional view of the telescopic shaft of the third embodiment, and FIG. 5 is a perspective view showing a state before a resin sleeve is attached to the male shaft and the female shaft is externally fitted.
As shown in FIG. 4, the telescopic shaft 30 of the present embodiment includes a male shaft 31, a female shaft 32, and an annular resin sleeve 33 that is fitted to the outer periphery of the male shaft 31.

The male shaft 31 has a solid columnar shape, and radially protrudes from the axial center on the outer periphery thereof, and four axial ridges 34 are formed at intervals of 90 degrees.
The female shaft 32 has a hollow cylindrical shape, and four axial grooves 35 having a substantially U-shaped cross section perpendicular to the axis are formed on the inner periphery of the female shaft 32 at the same phase position as the axial protrusion 34 of the male shaft 31. Yes.
The resin sleeve 33 has a hollow cylindrical shape, and is fitted on the outer periphery of the male shaft 31 so as to fill a gap between the axial protrusion 34 of the male shaft 31 and the axial groove 35 of the female shaft 32. On the outer periphery of the resin sleeve 33, a plurality of annular recesses 36 are formed continuously in the circumferential direction at predetermined intervals in the axial direction, and lubricant is accumulated in the annular recesses 36.

  Also in this embodiment, the resin sleeve 33 has a thickness set in a range of 100 to 2000 μm, and a material containing 5 to 50 wt% filler with respect to the total amount of the synthetic resin composition is fitted to the male shaft 31. Are combined. Further, the Mohs hardness of the filler of the resin sleeve 33 is set to 4.5 or less of the Mohs hardness of iron, and the low water absorption is 0.1 wt% or less as the base resin of the synthetic resin composition of the resin sleeve 33. Resin is used. Further, as the filler that accumulates in the annular recess 36, a filler that has been subjected to a surface treatment such as a silane coupling agent is used.

Therefore, the telescopic shaft 30 of the present embodiment having the above configuration can also achieve the same effects as the telescopic shaft 20 of the first embodiment.
The resin film made of a synthetic resin composition containing 5 to 50 wt% of a filler having a Mohs hardness of 4.5 or less is formed in the axial groove 35 of the female shaft 32 under the same conditions as the thickness of the resin sleeve 33. Even when formed with a base resin and a filler, the creep resistance is excellent, the sliding stability is improved even in a high-temperature and high-humidity environment, and the low-cost telescopic shaft 30 can be manufactured.

Next, FIG. 6 is a cross-sectional view showing the telescopic shaft of the fourth embodiment according to the present invention.
The telescopic shaft 40 of the fourth embodiment includes a male shaft 41, a female shaft 42, and a resin sleeve 44 fixed to the female shaft 42.
The male shaft 41 has a solid column shape, and on the outer periphery thereof, three axial ridges 45 project radially from the axial center and are spaced 120 degrees apart.

The female shaft 42 has a hollow cylindrical shape, and three axial grooves 46 having a substantially U-shaped cross section perpendicular to the axis are formed on the inner periphery of the female shaft 42 at the same phase position as the axial protrusion 45 of the male shaft 41. Yes.
Further, the male shaft 41 and the female shaft 42 are prevented from rotating by contacting the inner periphery of the axial groove 46 on the outer periphery of the axial ridge 45 of the male shaft 41, and the female shaft 42 slides in the axial direction. A resin sleeve 44 having a function to be fixed is fixed.

  And the resin sleeve 44 in this case is a film | membrane which set the thickness in the range of 100-2000 micrometers in the thinnest part, and contained 5-50 wt% filler with respect to the synthetic resin composition whole quantity. The Mohs hardness of the filler of the resin sleeve 44 is set to 4.5 or less of the Mohs hardness of iron, and as a base resin of the synthetic resin composition of the resin sleeve 44, a low water absorption resin having a water absorption rate of 0.1 wt% or less. Is used.

  Therefore, the telescopic shaft 40 of the present embodiment having the above configuration can also achieve the same effects as the telescopic shaft 20 of the first embodiment.

Next, Table 2 shows the results of evaluating the sliding stability and durability of the multiple types of telescopic shafts 20 in which the resin sleeves 23 having different synthetic resin compositions shown in the first embodiment are fitted to the male spline shafts 21. Show.
The male spline shaft 21 has an outer diameter of 20 mm and a length of 140 mm. The surface roughness of the portion of the male spline shaft 21 to which the resin sleeve 23 (length 50 mm) is fitted is air blasted to Ra 1.0. The surface is rough at ~ 1.5.

The resin sleeve 23 according to the first embodiment is formed by insert molding using the male spline shaft 21 as a core. The synthetic resin composition is a linear PPS synthetic resin composition (for example, Polyplasts Fortron (registered trademark) 3130A1 containing 30 wt% of potassium titanate isker surface treatment product), and the thickness is 500 μm.
In addition, the resin sleeve 23 of Example 2 contains a synthetic resin composition filler containing 25 wt% of a tetrafluoroethylene-ethylene copolymer synthetic resin composition (potassium titanate whisker surface-treated product, for example, manufactured by Otsuka Chemical Co., Ltd.). The difference from Example 1 is that it was Tismo Poticon FT24).

  Further, in the resin sleeve 23 of Example 3, the base resin of the synthetic resin composition is 70 wt% of polyamide 9T resin (for example, Kuraray Genesta (registered trademark) N100OA), and the filler of the synthetic resin composition is tetrapod. It differs from Example 1 in that it contains 30 wt% of a zinc oxide whisker surface-treated product (for example, Panatetra (registered trademark) WZ-0511 manufactured by Amtec).

  In Example 4, the base resin of the synthetic resin composition is 70 wt% of polyamide 12 resin (for example, UBESTA (registered trademark) 3024U manufactured by Ube Industries, which contains a heat stabilizer), and the synthetic resin composition The filler of 30 wt% of a titanic acid whisker surface-treated product (for example, Tesmo (registered trademark) D-102 manufactured by Otsuka Chemical Co., Ltd. and treated with an epoxy silane coupling agent) was used. Different from the first embodiment.

  Further, the fifth embodiment has almost the same configuration as the fourth embodiment, and the resin sleeve 23 is insert-molded using the male spline shaft 21 as a core, and then an epoxy silane coupling agent is applied to the surface of the male spline shaft 21 with a high frequency. It is applied by fusion (200 ° C., 30 seconds). The coating method is performed by immersing in a 5% ethanol solution of a silane coupling agent (for example, Epoxy silane coupling agent A-187: γ-glycidoxypropyltrimethoxysilane manufactured by Nihon Unicar) at room temperature for 10 seconds. A coating film was obtained on the surface of the spline shaft 21.

  Furthermore, in Example 6, the polyamide 66 resin (for example, UBE nylon 2020UW1: copper-based heat stabilizer containing) manufactured by Ube Industries is 60 wt%, and the filler of the synthetic resin composition is used as a wollastonite surface-treated product (for example, Kinsei). Example 1 differs from Example 1 in that it contains 40 wt% of WIC-10 manufactured by Matec and treated with an amino-based silane coupling agent.

  Comparative Example 1 is a conventional process (the process of coating the surface of the male spline shaft with a nylon film and applying grease to the sliding part: cleaning of the shaft → primer application → heating → nylon powder coating → rough cutting → finish cutting → On the surface of the male spline shaft that had been subjected to primer treatment after washing with a male spline shaft, a powder coating of nylon 11 (PA11: for example, Arkema's Rilsan BMN O TLD, thermal stabilizer / UV stabilizer added grade) was performed. A film was formed, and then a male spline shaft 21 adjusted to a film thickness of 500 μm by cutting was formed.

Comparative Example 2 is substantially the same as Example 1, and the resin sleeve 23 is formed only of nylon 66 (PA66).
(Evaluation of sliding stability)
The sliding stability of Examples 1 to 6 and Comparative Examples 1 and 2 was evaluated by applying grease to the surface of each male spline shaft specimen (Examples 1 to 5 and Comparative Example) and then female spline shaft 22. In an environment of 50 ° C. and 50% RH (hereinafter referred to as Condition I), or 60 ° C. and 90%
% RH (hereinafter referred to as Condition II), the sliding load was measured after a predetermined time (70 h, 300 h, 500 h), and the improvement improved by more than 20 wt% with respect to the initial value was rejected. A pass “×” was given, and a pass “○” was given below.

(Durability evaluation)
Each male spline shaft specimen (Examples 1 to 6 and Comparative Examples 1 and 2) whose sliding stability was confirmed was placed in an environment of 30 ° C. and 50% RH (hereinafter referred to as Condition III), 50 ° C. and 90 ° C. 10% at 80 ° C. and 50% RH (hereinafter referred to as Condition V), and at 80 ° C. and 90% RH (hereinafter referred to as Condition VI) in an environment of% RH (hereinafter referred to as Condition IV). After sliding 10,000 times, the noise level improved over 2dB with respect to the initial noise level was rejected as “x”, and the noise level was improved as 2dB or less as “good”. .

表２に示すように、充填剤を含有させた合成樹脂組成物を用いて樹脂スリーブ２３を形成することにより、摺動安定性が向上したことがわかる。そして、摺動安定性は、ベース樹脂に低吸水樹脂を用いることで、高温多湿環境でも優れた安定性を示すことがわかる。

As shown in Table 2, it can be seen that the sliding stability was improved by forming the resin sleeve 23 using the synthetic resin composition containing the filler. And it turns out that sliding stability shows the outstanding stability by using a low water absorption resin for base resin also in a hot and humid environment.

In addition, although there is no great difference in durability in a normal temperature and normal humidity environment, the synthetic resin compositions shown in Examples 1 and 2 are used in a high temperature environment in which creep is accelerated and in a humid environment in which water absorption dimensional change is expanded. The advantage was seen in what was used.
Moreover, even if it uses a nylon-type base resin, Example 1- Example 6 with a small water absorption dimensional change containing a filler by providing an adhesive layer uses the nylon-type resin which does not contain a filler. Compared with Comparative Examples 1 and 2, there is a significant difference in a humid environment. And it was confirmed that Example 2 which used the fluororesin which has a low friction coefficient as the base resin operate | moved by the lowest sliding load, and was excellent in slidability.

1 is an exploded perspective view of a telescopic shaft for vehicle steering according to a first embodiment of the present invention. It is a transverse cross section of the male axis of a 1st embodiment concerning the present invention. It is a cross-sectional view of the female shaft of the second embodiment according to the present invention. It is a cross-sectional view of the telescopic shaft of the third embodiment according to the present invention. It is a perspective view which shows the state before attaching a sleeve to the male shaft of 3rd Embodiment which concerns on this invention, and externally fitting a female shaft. It is a cross-sectional view of the telescopic shaft of the third embodiment according to the present invention. It is the figure which showed schematically the steering mechanism part of a motor vehicle.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Member on the vehicle body side, 2 ... Upper bracket, 3 ... Lower bracket, 4 ... Steering column, 5 ... Steering shaft, 6 ... Steering wheel, 7 ... Cardan shaft joint, 9 ... Cardan shaft joint, 10 ... Pinion shaft, 11 ... steering rack shafts 11 and 12 ... another frame of the vehicle body, 13 ... elastic body, 14 ... steering rack support member, 15 ... steering mechanism section, 20 ... telescopic shaft (vehicle steering telescopic shaft, steering shaft, intermediate shaft), DESCRIPTION OF SYMBOLS 21 ... Male spline shaft (male shaft), 22 ... Female spline shaft (female shaft), 23 ... Resin sleeve (resin layer), 24 ... Resin film (resin layer), 30 ... Telescopic shaft (telescopic shaft for vehicle steering, steering (Shaft, intermediate shaft), 31 ... male shaft (male shaft), 32 ... female shaft (female shaft), 33 ... resin three (Resin layer), 34 ... axial ridges, 35 ... axial grooves, 36 ... annular recess, 40 ... telescopic shaft, 41 ... male shaft, 42 ... female shaft, 44 ... resin sleeve, 45 ... axial ridge, 46 ... Axial groove

Claims (8)

In a vehicle steering mechanism, a telescopic shaft for vehicle steering in which a male shaft and a female shaft are non-rotatably and slidably fitted,
A telescopic shaft for vehicle steering, wherein a resin layer made of a synthetic resin composition containing 5 to 50 wt% of a filler is provided between the male shaft and the female shaft.   The telescopic shaft for vehicle steering according to claim 1, wherein the filler has a Mohs hardness of 4.5 or less.   The telescopic shaft for vehicle steering according to claim 1 or 2, wherein a thickness of the resin layer is set in a range of 100 to 2000 µm.   4. The filler according to claim 1, wherein the filler is at least one selected from potassium titanate whisker, zinc oxide whisker, basic magnesium sulfate, sepiolite, calcium carbonate whisker, and wollastonite. Telescopic shaft for vehicle steering as described.   The base resin containing the filler is a polyamide resin such as polyphenylene sulfide resin, polyether ether ketone resin, polyamide 6, polyamide 66, polyamide 46, polyamide 12, polyamide 11, modified polyamide 6T, polyamide 9T, polyamide MXD6, poly Heat-resistant synthesis made of fluororesin such as vinylidene fluoride, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluorovinyl ether copolymer, etc. The telescopic shaft for vehicle steering according to any one of claims 1 to 4, wherein the shaft is made of resin.   6. The expansion and contraction for vehicle steering according to claim 5, wherein the base resin containing the filler is a resin having a water absorption of 0.1 wt% or less after being left in a temperature environment of 23 ° C. for 24 hours. axis.   The telescopic shaft for vehicle steering according to any one of claims 1 to 6, wherein the resin layer is a resin sleeve provided on an outer periphery of the male shaft.   The telescopic shaft for vehicle steering according to any one of claims 1 to 6, wherein the resin layer is a resin film provided on an inner periphery of the female shaft.

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