JP6681018B2 - Stretchable shaft and manufacturing method thereof - Google Patents

Description

  The present invention relates to a telescopic shaft and a method for manufacturing the same.

  A telescopic shaft used in a vehicle steering device or the like is composed of a male shaft and a female shaft that are fitted to each other so as to be capable of transmitting torque and relatively movable in the axial direction. Therefore, the telescopic shaft is required to reduce play in the rotational direction of the male shaft and the female shaft and reduce sliding resistance between the male shaft and the female shaft. In order to meet these requirements, in the vehicle steering telescopic shaft of Patent Document 1 below, a buffer sleeve made of a composite material of a bronze mesh and a resin layer is interposed between a male shaft and a female shaft.

JP, 2003-54422, A

  Since the shock absorber sleeve of the vehicle steering telescopic shaft of Patent Document 1 contains an expensive material called a bronze mesh, the cost of the entire telescopic shaft may increase. The bumper sleeve is fixed to the female shaft by fitting the protrusion formed on the shock absorber sleeve into the hole formed in the female shaft. However, especially when manufacturing a female shaft whose diameter varies depending on the axial position by processing such as pipe expansion, it is difficult to realize the diameter dimension with accuracy, and the fitting part of the female shaft has the axial front side (opening). The inner dimension changes between the side) and the back side. For this reason, rattling between the buffer sleeve and the female shaft, and further rattling between the female shaft and the male shaft becomes large, and slidability may be deteriorated.

  The present invention has been made under such a background, and provides a telescopic shaft capable of suppressing the cost and improving slidability between the male shaft and the female shaft, and a manufacturing method thereof. The purpose is to

The invention according to claim 1 includes a male shaft (2) having a fitting shaft portion (21) at one end (2a) and a hollow fitted portion (31) at one end (3a), A female-side shaft (3) in which a fitted portion is fitted so as to be movable relative to the fitting shaft portion, and an intermediate member (4) interposed between the fitting shaft portion and the fitted portion. And a through hole (33) that penetrates the fitted portion from the inner surface to the outer surface is formed in the fitted portion, and the intermediate member has a recessed portion at least in a region facing the through hole. (43) is provided, and further includes a fixing member (5) that fills the recess from the through hole and fixes the intermediate member in the fitted portion, the fitting shaft portion and the fitted portion. during the relative movement of the engaging portion, the fitting shaft portion slides with respect to the surface of the fitting shaft portion side of the intermediate member, said fixing member The portion is interposed between a portion of the intermediate member on the side of the fitted portion that is displaced from the recess in the axial direction or the circumferential direction of the fitting shaft portion and the inner surface of the fitted portion. The telescopic shaft (1) is characterized in that

The invention described in 請 Motomeko 2 is provided with one end (2a) male shaft with the fitting shaft portion (21) to (2), the fitted portion of the hollow at one end (3a) and (@ 31 P), A female-side shaft (3) in which the fitted portion is fitted so as to be relatively movable with the fitting shaft portion, and an intermediate member (4P) interposed between the fitting shaft portion and the fitted portion. And a hole (35) recessed from the inner surface of the fitted portion toward the outer surface is formed in the fitted portion, and the intermediate member has a boundary surface with the fitted portion. Including a welding layer (6) that spreads over a part of the hole and is welded to the fitted portion, and when the fitting shaft portion and the fitted portion are relatively moved, The fitting shaft portion is a telescopic shaft (1P) that slides on the surface of the intermediate member on the fitting shaft portion side.

According to a third aspect of the present invention, the intermediate member includes a pair of split bodies (46) sandwiching the fitting shaft portion from a direction (Y) orthogonal to the axial direction (X) of the fitting shaft portion. The telescopic shaft according to claim 1 or 2 , which is characterized .

The invention according to claim 4 comprises a male shaft (2) having a fitting shaft portion (21) at one end (2a), and a hollow fitted portion (31P) at one end (3a), A hole (35) is formed on the inner surface of the fitted portion, and the female shaft (3) fitted to the fitted portion such that the fitted portion can move relative to the fitting shaft portion, and the fitting shaft portion. A method of manufacturing an expansion / contraction shaft (1P) including a resin-made intermediate member (4P) interposed between the fitting member and the fitted portion, wherein: By pressing the intermediate member between the fitting shaft portion and the fitted portion while the ultrasonic vibration is being transmitted, the intermediate member is pushed against the fitted portion. A step of press-fitting the intermediate member between the fitted portion and the fitting shaft portion while melting the resin (73) in the portion where Curing the melted the resin, characterized in that it comprises a a method for manufacturing a telescopic shaft.

Invention of claim 5, wherein the step of press-fitting said intermediate member between the fitting shaft portion and the fitted portion is melted the in the hole formed on the inner surface of the fitting portion and the The method of manufacturing an expandable shaft according to claim 4 , further comprising a step of allowing a resin to enter.
In the above description, the numbers in parentheses represent reference numerals of corresponding components in the embodiments described later, but these reference numerals do not limit the scope of the claims.

  According to the invention described in claim 1, the fitting shaft portion does not slide on the inner surface of the fitted portion but slides on the surface of the intermediate member on the fitting shaft portion side. The fixing member is filled from a through hole that penetrates the fitted portion from the inner surface to the outer surface to a recess provided in a region facing the through hole. Therefore, the fixing member firmly fixes the intermediate member to the fitted portion along the fitting shaft portion. Accordingly, it is possible to absorb the dimensional variation of the fitted portion. Therefore, rattling can be suppressed while reducing the sliding resistance between the male side shaft and the female side shaft. That is, the slidability can be improved.

Further, since it is not necessary to provide the intermediate member with a special material or to perform special processing on the intermediate member in order to improve the slidability, the cost can be suppressed.
Further , since a part of the fixing member is interposed between the inner surface of the fitted portion and the surface of the intermediate member on the fitted portion side, there is a gap between the fitted portion and the intermediate member. It's getting in. Therefore, the intermediate member can be more firmly fixed to the fitted portion with the intermediate member along the fitting shaft portion. Therefore, it is possible to further absorb the dimensional variation of the fitted portion, so that it is possible to further reduce the rattling while reducing the sliding resistance between the male shaft and the female shaft.

According to the invention of claim 2 , the fitting shaft portion does not slide on the inner surface of the fitted portion but slides on the surface of the intermediate member on the fitting shaft portion side. The intermediate member includes a welding layer which spreads on the boundary surface with the fitted portion and a part of which enters a hole which is recessed from the inner surface of the fitted portion toward the outer surface. Therefore, the welding layer firmly fixes the intermediate member to the fitted portion along the fitting shaft portion. Accordingly, it is possible to absorb the dimensional variation of the fitted portion. Therefore, rattling can be suppressed while reducing the sliding resistance between the male side shaft and the female side shaft. That is, the slidability can be improved.

Further, since it is not necessary to provide the intermediate member with a special material or to perform special processing on the intermediate member in order to improve the slidability, the cost can be suppressed.
According to the third aspect of the present invention, the pair of split bodies can sandwich the fitting shaft portion from the direction orthogonal to the axial direction with an appropriate force, so that there is a gap between the intermediate member and the fitting shaft portion. It is possible to suppress wobbling.

According to the invention described in 請 Motomeko 4, when to press fit the intermediate member between the fitted portion and the fitting shaft portion, the molten resin is pressed against the fitted portion, the engagement portion The intermediate member and the intermediate member can be made to spread, and a part of the intermediate member can be hardened in the hole formed in the inner surface of the fitted portion. With this, the intermediate member can be firmly fixed to the fitted portion along the fitting shaft portion, so that the dimensional variation of the fitted portion can be absorbed. Therefore, rattling can be suppressed while reducing the sliding resistance between the male side shaft and the female side shaft. That is, the slidability can be improved.

  Further, since it is not necessary to provide the intermediate member with a special material or to perform special processing on the intermediate member in order to improve the slidability, the cost can be suppressed.

It is a schematic diagram of an electric power steering device provided with a telescopic shaft concerning the present invention. It is a schematic sectional drawing of the expansion-contraction shaft which concerns on 1st Embodiment of this invention. FIG. 3 is a schematic cross-sectional view taken along the line III-III of FIG. 2. It is a perspective view of an intermediate member. It is the figure which looked at a division body from the inner surface side. It is the figure which showed the expansion-contraction axis | shaft of the 1st modification, and is a figure equivalent to the sectional view along the III-III line of FIG. It is the figure which showed the expansion-contraction axis | shaft of the 2nd modification, and is a figure corresponded to the sectional view along the III-III line of FIG. It is the typical sectional view which expanded the circumference of a fixed member. It is a schematic diagram which shows the manufacturing process of the expansion-contraction shaft which concerns on 1st Embodiment. FIG. 9B is a schematic diagram showing the next step of FIG. 9A. FIG. 9B is a schematic diagram showing the next step of FIG. 9B. It is a schematic sectional drawing of the expansion-contraction shaft which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows the manufacturing process of the telescopic shaft which concerns on 2nd Embodiment. FIG. 11B is a schematic diagram showing the next step of FIG. 11A. FIG. 12C is a schematic diagram showing the next step of FIG. 11B. In the manufacturing process of the expansion-contraction shaft which concerns on 2nd Embodiment, it is the schematic which showed the state in the middle of a press-fitting process, and is the schematic diagram which expanded the one end vicinity of the to-be-fitted part in the axial direction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram of an electric power steering apparatus 10 including a telescopic shaft 1 according to the present invention.
With reference to FIG. 1, the telescopic shaft 1 has a male-side shaft 2 and a female-side shaft 3 that are fitted so as to be movable relative to each other in the axial direction X of the telescopic shaft 1 and integrally rotatable with the male-side shaft 2. It is a shaft that includes an intermediate member 4 that slides and is fixed to the female-side shaft 3. The expandable shaft 1 is expandable and contractable in the axial direction X, and can transmit a rotational torque between the male shaft 2 and the female shaft 3.

  The telescopic shaft 1 is applied to, for example, a shaft that constitutes the steering shaft 12 together with the lower shaft 11. In this case, the female-side shaft 3 is, for example, the upper shaft 18A to which the rotational torque from the steering member 13 is input, and the male-side shaft 2 is, for example, the intermediate shaft 18B that outputs the rotational torque to the lower shaft 11. . At the time of telescopic adjustment of the steering member 13, the upper shaft 18A and the intermediate shaft 18B relatively move in the axial direction X, whereby the telescopic shaft 1 expands and contracts. The female shaft 3 may be applied to the intermediate shaft 18B, and the male shaft 2 may be applied to the upper shaft 18A.

The lower shaft 11 is connected to the intermediate shaft 18B. The lower shaft 11 is provided with a reduction mechanism 14 that reduces the power from the electric motor 17 and transmits the reduced power to the lower shaft 11.
The steering shaft 12 transmits the steering force of the steering member 13 to the steered mechanism A via the expandable intermediate shaft 15 and the pinion shaft 16 to steer steered wheels (not shown).

  The telescopic shaft 1 of the present embodiment can be applied not only to the steering shaft 12 of the electric power steering device 10 but also to a steering shaft of a manual type steering device having no electric motor 17. In this case, for example, the female shaft 3 is an upper shaft to which the rotational torque from the steering member 13 is input, and the male shaft 2 is a lower shaft that transmits the rotational torque to the intermediate shaft 15.

  Further, the expandable shaft 1 can be applied to an expandable shaft such as the intermediate shaft 15. Further, the telescopic shaft 1 can be applied to telescopic shafts included in in-vehicle components other than the steering device, and can also be applied to mechanical devices other than in-vehicle components, such as railway vehicles and wind power generators.

<First Embodiment>
Below, the expansion-contraction axis | shaft 1 of 1st Embodiment of this invention is demonstrated in detail.
FIG. 2 is a schematic sectional view of the telescopic shaft 1 of the first embodiment. FIG. 3 is a schematic cross-sectional view taken along the line III-III of FIG.
With reference to FIG. 2, the male shaft 2 includes a fitting shaft portion 21 having a predetermined length in the axial direction X at one end 2 a in the axial direction X. One end 3a of the female shaft 3 in the axial direction X is formed hollow. The female shaft 3 includes a hollow fitted portion 31 into which the fitting shaft portion 21 is fitted, at one end 3a in the axial direction X. The fitted portion 31 has an opening 32a at one end. A receiving space 32 capable of receiving the fitting shaft portion 21 from the opening 32a toward the inside of the shaft is formed in the fitted portion 31. The fitted portion 31 is fitted to the fitting shaft portion 21 so as to be relatively movable in the axial direction X.

With reference to FIG. 3, the fitting shaft portion 21 and the fitted portion 31 are, for example, oval (oval) when viewed in the axial direction X. The direction along the outer surface of the fitting shaft portion 21 (the surface on the fitting portion 31 side) and the inner surface of the fitting portion 31 (the surface on the fitting shaft portion 21 side) that is orthogonal to the axial direction X is determined. Let's call it direction C.
At least one through hole 33 is formed in the female shaft 3. The through hole 33 penetrates the fitted portion 31 from its inner surface to its outer surface. In this embodiment, two pairs of through holes 33 are formed at intervals in the axial direction X (see FIG. 2). The pair of through holes 33 are provided apart from each other in the circumferential direction C. For example, the pair of through holes 33 are separated from each other by 180 ° in the circumferential direction C.

  Referring to FIG. 2, the intermediate member 4 is a member that is interposed between the fitted portion 31 and the fitting shaft portion 21 and fills the gap between the male-side shaft 2 and the female-side shaft 3. As the intermediate member 4, it is preferable to use a material having high wear resistance. Examples of the material used for the intermediate member 4 include resins such as polyacetal. The intermediate member 4 is formed by resin molding using a mold or the like. The intermediate member 4 has a hollow, substantially tubular shape extending in the axial direction X as a whole. A flange portion 42, which extends from the one end 4a of the intermediate member 4 in the radial direction and contacts the one end 3a of the female-side shaft 3, is connected to one end 4a of the intermediate member 4 in the axial direction X.

  2 and 3, the intermediate member 4 has an outer surface (a surface on the fitted portion 31 side) along an inner surface (a surface on the intermediate member 4 side) of the fitted portion 31, and The inner surface (the surface on the fitting shaft portion 21 side) is arranged along the outer surface (the surface on the intermediate member 4 side) of the fitting shaft portion 21. When the fitting shaft portion 21 and the fitted portion 31 are relatively moved, the inner surface of the intermediate member 4 is slidable with respect to the outer surface of the fitting shaft portion 21. The outer shape and the inner shape of the intermediate member 4 are oval (oval) when viewed in the axial direction X.

  A recess 43 is provided on the outer surface of the intermediate member 4. Specifically, the recess 43 is provided on the outer surface of the intermediate member 4 at least in a region facing the through hole 33. In this embodiment, the recess 43 faces the inner surface of the fitted portion 31. A plurality of recesses 43 may be provided in the circumferential direction C. The pair of recesses 43 are formed at least at two locations (two locations in this embodiment) at intervals in the axial direction X. A total of four recesses 43 are formed in the intermediate member 4. Two recesses 43 at the same position in the axial direction X are provided at intervals in the circumferential direction C. Each recess 43 must communicate with one or more through holes 33.

As in this embodiment, by forming the recesses 43 at least at two positions with a space in the axial direction X, the vicinity of one end side and the other end side vicinity of the intermediate member 4 in the longitudinal direction (corresponding to the axial direction X) are formed. Serves as a fixing portion, and the intermediate member 4 can be stably fixed in the receiving space 32 of the female shaft 3.
With reference to FIG. 4, which is a perspective view of the intermediate member 4, as in this embodiment, the intermediate member 4 has the fitting shaft portion 21 from the direction Y orthogonal to the axial direction X (the vertical direction of the paper surface of FIG. 4). It may be constituted by a pair of divided bodies 46 sandwiched therebetween. The orthogonal direction Y is a direction that passes through the central axis A1 of the fitting shaft portion 21 among the directions orthogonal to the axial direction X (see FIG. 2). Each divided body 46 has a semi-cylindrical shape. On the outer surface of each divided body 46, two recesses 43 extending in the circumferential direction (corresponding to the circumferential direction C of the intermediate member 4) are formed at intervals in the axial direction X.

With reference to FIG. 3, a pair of split bodies 46 are brought close to each other so that their inner surfaces face each other, and their circumferential end portions are aligned with each other to form a substantially tubular intermediate member 4 as a whole. . In this state, a gap is provided between the circumferential ends 46a of the split bodies 46. A gap is provided between the other ends 46b of the divided body 46 in the circumferential direction.
With reference to FIG. 5, which is a view of the split body 46 from the inner surface side, the grease for accumulating grease for smooth sliding between the intermediate member 4 and the fitting shaft portion 21 is provided on the inner surface of the split body 46. The groove 48 may be formed. For convenience of explanation, illustration of the grease groove 48 is omitted in figures other than FIGS. 4 and 5. The grease groove 48 is composed of, for example, a plurality of grooves extending obliquely with respect to the axial direction X. By combining the divided bodies 46 provided with the grease grooves 48, a spiral grease groove extending in the axial direction X may be formed over the entire inner surface of the intermediate member 4. The grease groove 48 may include a circumferential groove extending along the circumferential direction C of the inner surface of the intermediate member 4. When the intermediate member 4 is manufactured using a mold, the grease groove 48 can be formed at the same time when the intermediate member 4 is molded. Therefore, since it is not necessary to form the grease groove 48 by cutting or the like after the molding of the intermediate member 4, the preparation of the intermediate member 4 becomes easy.

  Further, unlike the present embodiment, the intermediate member 4 may include a hollow tubular body 41 that is not discontinuous in the circumferential direction C (continuous in the circumferential direction C) (see the alternate long and short dash line in FIG. 4). The tubular body 41 may be provided with a notch 41a extending in the axial direction X from the axial end portion of the tubular body 41. It is preferable that the notch 41a extends so as to avoid the portion where the recess 43 is formed.

With reference to FIG. 2, the telescopic shaft 1 further includes a fixing member 5 that fixes the intermediate member 4 in the fitted portion 31 (reception space 32). The fixing member 5 may be in contact with the outer surface of the intermediate member 4 and the inner surface of the fitted portion 31.
As the fixing member 5, it is preferable to use a material having high fluidity. Examples of the material used for the fixing member 5 include resins such as polyacetal. The fixing member 5 may be formed of an elastic body such as an elastomer.

  In this embodiment, the fixing member 5 is filled in the recess 43 from the through hole 33. The fixing member 5 is filled in the through-hole 33 and the filled portion 51 at least a part of which is filled in the concave portion 43, so that the intermediate member 4 can move axially and circumferentially (rotate) relative to the fitted portion 31. And a regulating unit 52 for regulating. The fixed member 5 is an interposed portion 55 interposed between the inner surface of the fitted portion 31 and the outer surface of the intermediate member 4 (the outer surface 4c of the recess 43 that is offset in the axial direction X or the circumferential direction C). May be included.

Since the concave portion 43 faces the inner surface of the fitted portion 31, the filled portion 51 filled in the concave portion 43 also faces the inner surface of the fitted portion 31. Therefore, the fixing member 5 can be prevented from coming off from the through hole 33.
Since the intermediate member 4 is fixed to the fitted portion 31 of the female shaft 3 by the fixing member 5, the fitting shaft portion 21 of the male shaft 2 and the fitted portion 31 of the female shaft 3 move relative to each other. At this time, the intermediate member 4 moves relative to the fitting shaft portion 21 together with the fitted portion 31. Therefore, the fitting shaft portion 21 does not slide on the inner surface of the fitted portion 31, but slides on the inner surface of the intermediate member 4 (the surface on the fitting shaft portion 21 side).

FIG. 6 is a diagram showing the telescopic shaft 1 of the first modification, and FIG. 7 is a diagram showing the telescopic shaft 1 of the second modification. 6 and 7 are views corresponding to a cross-sectional view taken along the line III-III in FIG. 2.
In the telescopic shaft 1 of the first modification, the fitting shaft portion 21 of the male shaft 2 and the fitted portion 31 of the female shaft 3 are hexagonal when viewed in the axial direction X. In the telescopic shaft 1 of the second modified example, the fitting shaft portion 21 of the male shaft 2 and the fitted portion 31 of the female shaft 3 have a cross shape when viewed in the axial direction X. Although not shown, the fitting shaft portion 21 and the fitted portion 31 may have an elliptical shape when viewed in the axial direction X, or may have a polygonal shape such as a square shape. The point is that the shafts may have a shape such that they do not rotate relative to each other. For example, even if the cross section is circular, a so-called spline shaft having irregularities extending in the axial direction of the shaft may be used.

  According to the first embodiment, the fitting shaft portion 21 does not slide on the inner surface of the fitted portion 31 but slides on the inner surface of the intermediate member 4. The fixing member 5 is filled in the recess 43 from the through hole 33. Therefore, the fixing member 5 firmly fixes the intermediate member 4 to the fitted portion 31 along the fitting shaft portion 21. Thereby, the dimensional variation of the fitted portion 31 can be uniformly absorbed in the axial direction X. Therefore, it is possible to reduce the sliding resistance between the male-side shaft 2 and the female-side shaft 3 while suppressing the rattling. That is, the slidability can be improved.

Further, in order to improve the slidability, the intermediate member 4 is provided with a special material (for example, a resin containing a bronze mesh used for the expandable shaft of Patent Document 1), or the intermediate member 4 is subjected to special processing. Since there is no need to do so, it is possible to suppress an increase in cost.
Further, with reference to FIG. 8 which is a schematic cross-sectional view in which the periphery of the fixing member 5 is enlarged, if the inner diameter of the fitted portion 31 varies depending on the axial position, especially toward the opening 32a, gradually. In the case where it spreads, a slight gap S may occur between the inner surface of the fitted portion 31 and the outer surface of the intermediate member 4. Note that, in FIG. 8, for clarity, the variation of the dimension of the fitted portion 31 depending on the axial position is exaggeratedly shown.

  However, a part of the fixed member 5 (the interposed portion 55) is inserted between the inner surface of the fitted portion 31 and the outer surface 4c of the intermediate member 4 and thus enters the gap S. Therefore, even when the gap S is generated, the intermediate member 4 can be firmly fixed to the fitted portion 31 with the intermediate member 4 along the fitting shaft portion 21. Therefore, it is possible to further absorb the dimensional variation of the fitted portion 31, so that it is possible to further reduce rattling while reducing the sliding resistance between the male shaft 2 and the female shaft 3.

The fixing member 5 may apply an appropriate pressing force F1 to the fitting shaft portion 21 via the intermediate member 4. In this case, since the gap between the fitting shaft portion 21 and the intermediate member 4 is reduced, the sliding resistance between the male-side shaft 2 and the female-side shaft 3 is reduced and rattling is further suppressed. be able to.
When the intermediate member 4 is composed of a pair of split bodies 46 (see FIG. 4), the pair of split bodies 46 sandwich the fitting shaft portion 21 from the direction Y orthogonal to the axial direction X with an appropriate force. Therefore, the gap between the fitting shaft portion 21 and the intermediate member 4 can be closed. In this case, since the dimensional variation of each member (fitting shaft portion 21 and fitted portion 31) can be absorbed, measurement of sliding force and rattling for each product can be omitted, and the cost can be reduced. You can

Next, a method of manufacturing such a telescopic shaft 1 will be described.
9A to 9C are schematic views sequentially showing the manufacturing process of the expandable shaft 1.
In advance, the female shaft 3 having the fitted portion 31 and having the through hole 33 formed therein and the intermediate member 4 having the recess 43 formed therein are prepared. A grease groove 48 (see FIG. 4) may be formed in the prepared intermediate member 4. Here, an already manufactured product may be prepared, or a process of manufacturing such a member (female side shaft preparation process, intermediate member preparation process) may be set in advance.

First, as shown in FIG. 9A, a mounting step of mounting the intermediate member 4 on the fitting shaft portion 21 of the male shaft 2 combined with the female shaft 3 is performed. In the mounting step, the pair of split bodies 46 are mounted so as to sandwich the fitting shaft portion 21 of the male shaft 2 from the orthogonal direction Y.
Next, as shown in FIG. 9B, the fitting shaft portion 21 of the male side shaft 2 to which the intermediate member 4 is attached is inserted into the fitted portion 31 of the female side shaft 3 so that the concave portion 43 has the through hole 33. The inserting step of interposing the intermediate member 4 between the fitting shaft portion 21 and the fitted portion 31 is performed so as to be opposed to. In the inserting step, the flange portion 42 connected to the intermediate member 4 is brought into contact with the one end 3a of the female-side shaft 3 so that the concave portion 43 and the through hole 33 can be aligned in the axial direction X so as to face each other. it can.

  In the mounting step and the inserting step, the intermediate member 4 is mounted on the fitting shaft portion 21 of the male side shaft 2 and then these are inserted into the fitted portion 31 of the female side shaft 3. Not limited to this, for example, when the intermediate member 4 is configured by one component (when configured by the tubular body 41), the intermediate member 4 is installed in the receiving space 32 of the female-side shaft 3 and then Alternatively, the fitting shaft portion 21 of the male shaft 2 may be inserted into the intermediate member 4. That is, any method may be used as long as the intermediate member 4 is interposed between the fitting shaft portion 21 of the male shaft 2 and the fitted portion 31 of the female shaft 3.

Next, as shown in FIG. 9C, a molding step of injecting the liquid resin 72 into the recess 43 from the outside of the female shaft 3 through the through hole 33 and curing the resin is performed.
In the molding step, for example, a pair of molds 70 for injection molding are used. Specifically, first, the female-side shaft 3 and the intermediate member 4 are inserted into the female-side shaft 3 in a state where the female-side shaft 3 and the intermediate member 4 are mounted between a pair of molds 70 facing each other in a direction orthogonal to the axial direction X. And the male side shaft 2 that has been set. At this time, the positions of the gate 71 for injecting the molten resin 72 provided in each mold 70 and the through hole 33 are aligned. In this state, the molten resin 72 is injected from the gate 71 into the through hole 33. When the resin 72 injected into the through hole 33 spreads over the through hole 33 and the recess 43, the injection of the molten resin 72 is stopped, and the resin 72 is cooled and solidified via the pair of molds 70. As a result, the fixing member 5 (see FIG. 2) is formed.

As described above, the manufacture of the telescopic shaft 1 capable of suppressing the rattling while reducing the sliding resistance between the male shaft 2 and the female shaft 3 is completed.
According to this manufacturing method, the resin 72 can be injected into the recess 43 from the outside of the fitted portion 31 of the female shaft 3 through the through hole 33 to cure the resin 72 filled in the recess 43 and the through hole 33. it can. Therefore, the intermediate member 4 can be firmly fixed to the fitted portion 31 along the fitting shaft portion 21, so that the dimensional variation of the fitted portion 31 is uniformly absorbed in the axial direction X. can do. Therefore, it is possible to manufacture the telescopic shaft 1 that can reduce the cost and improve the slidability between the male-side shaft 2 and the female-side shaft 3.

  In particular, in the case where the expandable shaft 1 is manufactured using a pair of molds 70 for injection molding (see FIG. 9C) in the molding process, the pressure applied to the resin 72 during injection molding (injection pressure) As shown in FIG. 8, the molten resin 72 cures while pressing the intermediate member 4. Therefore, the fixing member 5, which is the cured resin 72, can apply an appropriate pressing force F1 to the fitting shaft portion 21 via the intermediate member 4. As a result, the space between the fitting shaft portion 21 and the intermediate member 4 is further closed.

Further, due to the injection pressure, a part of the melted resin 72 is injected into the gap S (hardened in the gap S) and hardened. Thereby, the dimensional variation of the fitted portion 31 is further absorbed.
Further, when the intermediate member 4 is configured by the pair of divided bodies 46, the pair of divided bodies 46 sandwich the fitting shaft portion 21 from the orthogonal direction Y, so that the fitting shaft portion 21 and the intermediate member 4 are separated from each other. It can be packed even more.

Even when the intermediate member 4 is configured by the tubular body 41, the tubular body 41 contracts so as to narrow the notch 41 a when the intermediate member 4 receives the pressing force from the fixing member 5. By making the diameter and sandwiching the fitting shaft portion 21 from the direction Y orthogonal to the axial direction X, it is possible to further close the space between the fitting shaft portion 21 and the intermediate member 4.
Further, since the resin 72 is injected into the recess 43 provided on the outer surface of the intermediate member 4 and cured, it is possible to prevent the resin 72 from curing while being in contact with the fitting shaft portion 21. Therefore, since the resin 72 is hard to stick to the fitting shaft portion 21 due to the hardening, the fitting shaft portion 21 and the intermediate member 4 can be slid smoothly.

<Second Embodiment>
Below, the expansion-contraction shaft 1P of 2nd Embodiment is demonstrated in detail.
FIG. 10 is a schematic sectional view of a telescopic shaft 1P according to the second embodiment of the present invention. In the second embodiment, the same members as those described in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The same applies to FIGS. 11A to 12 described later.

  The expandable shaft 1P of the second embodiment is mainly different from the expandable shaft 1 of the first embodiment in the following points. In the expansion / contraction shaft 1P, the intermediate member 4P spreads on the boundary surface with the fitted portion 31P, and a part of the intermediate member 4P (a restricting portion 53 to be described later) has entered the hole 35 formed in the fitted portion 31. The welding layer 6 welded to the fitting portion 31P is included. The boundary surface with the fitted portion 31P is a surface that is in contact with the inner surface of the fitted portion 31P on the outer surface of the intermediate member 4P. The welding layer 6 does not have to spread over the entire boundary surface with the fitted portion 31P, and the intermediate member 4P may be firmly fixed to the fitted portion 31P.

  In addition, the fitted portion 31P is formed with a hole 35 that is recessed from the inner surface of the fitted portion 31P toward the outer surface. The hole 35 may be a through hole that penetrates from the inner surface to the outer surface of the fitted portion 31P. The hole 35 may have a bottom as shown by the broken line in FIG. When the hole 35 has a bottom portion, the fitted portion 31P is provided with an air hole (not shown) that communicates the hole 35 with the outside of the fitted portion 31P and allows air to pass therethrough. Preferably.

The welding layer 6 is interposed between the restriction portion 53 that restricts the axial movement and the circumferential movement (rotation) of the intermediate member 4P with respect to the fitted portion 31P, and the covered portion interposed between the intermediate member 4P and the fitted portion 31P. The interposition part 54 is included. The regulating portions 53 are provided in the same number as the holes 35.
The restricting portion 53 is inserted into the hole 35 from the inner surface side (intermediate member 4P side) of the fitted portion 31P. The interposed portion 54 extends to the boundary surface of the intermediate member 4P. The interposed portion 54 is welded to the inner surface of the fitted portion 31P.

  According to the second embodiment, the fitting shaft portion 21 does not slide on the inner surface of the fitted portion 31P but the inner surface of the intermediate member 4P (the surface on the fitting shaft portion 21 side). Slide. The intermediate member 4P includes the welding layer 6 which spreads to the boundary surface with the inner surface of the fitted portion 31P and a part of which enters the hole 35. Therefore, the intermediate layer 4P is firmly fixed to the fitted portion 31P along the fitting shaft portion 21 by the welding layer 6. Accordingly, it is possible to uniformly absorb the dimensional variation of the fitted portion 31P in the axial direction X. Therefore, it is possible to reduce the sliding resistance between the male-side shaft 2 and the female-side shaft 3 while suppressing the rattling. That is, the slidability can be improved.

Further, in order to improve the slidability, the intermediate member 4P is provided with a special material (for example, a resin containing a bronze mesh used for the expandable shaft of Patent Document 1), or the intermediate member 4P is subjected to special processing. Since it is not necessary to do so, the cost can be suppressed.
Further, even if a gap S (see FIG. 8) is generated between the inner surface of the fitted portion 31 and the outer surface of the intermediate member 4P, the welding layer 6 spreads to the boundary surface. Therefore, it enters the gap S. Therefore, the dimensional variation of the fitted portion 31P can be further absorbed.

  Further, when the intermediate member 4P is composed of the pair of divided bodies 46, the pair of divided bodies 46 can sandwich the fitting shaft portion 21 from the direction Y orthogonal to the axial direction X with an appropriate force. The gap between the coupling shaft portion 21 and the intermediate member 4P can be reduced. In this case, the dimensional variation of each member (fitting shaft portion 21 and fitted portion 31P) can be absorbed, so that measurement of sliding force and rattling for each product can be omitted, and cost can be reduced. You can

Moreover, the same modification as 1st Embodiment can be applied also to the expansion-contraction shaft 1P of 2nd Embodiment.
Next, a method of manufacturing the expandable shaft 1P will be described.
11A to 11C are schematic views sequentially showing the manufacturing process of the expandable shaft 1P. Detailed description of the same steps as the method of manufacturing the expandable shaft 1 of the first embodiment will be omitted.

  First, the female-side shaft 3 having the fitted portion 31P in which the hole 35 is formed and the intermediate member 4P are prepared in advance. A grease groove 48 (see FIG. 4) may be formed in the prepared intermediate member 4P. Here, an already manufactured product may be prepared, or a process for manufacturing such a member (female side shaft preparation process, intermediate member preparation process) may be set in advance.

Then, an external fitting step of externally fitting the intermediate member 4P to the fitting shaft portion 21 of the male shaft 2 combined with the female shaft 3 is performed.
When the intermediate member 4P includes a pair of divided bodies 46 (see FIG. 4), in the external fitting process, a pair of divided bodies is formed as in the mounting process (see FIG. 9A) of the method for manufacturing the expandable shaft 1 of the first embodiment. The body 46 fits the fitting shaft portion 21 of the male shaft 2 so as to sandwich it from the orthogonal direction Y. When the intermediate member 4P includes the tubular body 41 (see FIG. 4), the fitting shaft portion 21 is inserted into the tubular body 41 and externally fitted to the tubular body 41 in the external fitting process. The intermediate member 4P fitted onto the fitting shaft portion 21 can smoothly slide in the axial direction X with respect to the fitting shaft portion 21.

Then, as shown in FIG. 11A, the fitting shaft portion 21 of the male shaft 2 is moved relative to the intermediate member 4P, and the fitting shaft portion 21 is inserted into the fitted portion 31P from the opening 32a and arranged. The placement step is performed.
Then, as shown in FIG. 11B, a press-fitting process is performed in which the press-fitting jig 60 is used to press-fit between the fitting shaft portion 21 and the fitted portion 31P. Specifically, first, with the position of the female-side shaft 3 fixed by the fixing portion 60a of the press-fitting jig 60, the intermediate member 4P is moved to the fitted portion 31P using the movable portion 60b of the press-fitting jig 60. Let As a result, the intermediate member 4P is press-fitted from the one end 3a of the female shaft 3 between the fitted portion 31P and the fitting shaft portion 21. In other words, the intermediate member 4P is inserted between the fitted portion 31P and the fitting shaft portion 21 in a state where the intermediate member 4P has the tightening margin D (see FIG. 12). The tightening margin D is preferably provided so as to be uniform over the entire circumference in the circumferential direction C.

In the press-fitting process, in a state where the intermediate member 4P is pressed between the fitting shaft portion 21 and the fitted portion 31P, transmission of ultrasonic vibration to the intermediate member 4P is started via the movable portion 60b.
By pressing the intermediate member 4P between the fitting shaft portion 21 and the fitted portion 31P in a state where ultrasonic vibration is transmitted to the intermediate member 4P fitted onto the fitting shaft portion 21, Friction heat is generated between the inner surface of the fitted portion 31P and the outer surface of the intermediate member 4P. As a result, as shown in FIG. 12, the intermediate member 4P can be press-fitted between the fitted portion 31P and the fitting shaft portion 21 while melting the resin 73 in the portion near the inner surface of the fitted portion 31P. Along with the press-fitting of the intermediate member 4P, a part of the resin 73 (resin 73a) melted enters the hole 35 of the fitted portion 31P, and the rest of the resin 73 melted (resin 73b) is intermediate with the fitted portion 31P. It invades and spreads with the member 4P.

At the other end 4b in the axial direction X of the intermediate member 4P before being press-fitted between the fitted portion 31P and the fitting shaft portion 21, it is inserted between the fitted portion 31P and the fitting shaft portion 21. For convenience, the outer surface of the intermediate member 4P may be inclined with respect to the axial direction X.
The press-fitting of the intermediate member 4P into the fitting shaft portion 21 and the fitted portion 31P may be performed until the flange portion 42 contacts the one end 3a of the female-side shaft 3.

  As shown in FIG. 11C, when the press-fitting is completed and the transmission of the ultrasonic vibration to the intermediate member 4P is stopped, the press-fitting process is ended. By stopping the transmission of ultrasonic vibration, frictional heat is not generated, the resin 73 is cooled to room temperature and solidified (cured), and the welding layer 6 is formed. In order to cool the resin 73 to room temperature, a step of cooling and solidifying the resin 73 using a cooling device (not shown) may be separately provided after the press-fitting step.

As described above, the manufacture of the telescopic shaft 1P capable of suppressing the rattling while reducing the sliding resistance between the male shaft 2 and the female shaft 3 is completed.
According to this manufacturing method, the resin 73 that has been pressed against the fitted portion 31P and melted is caused to enter and spread between the fitted portion 31P and the intermediate member 4P, and a part thereof (the regulating portion 53). Can be hardened in a state where it enters the hole 35. As a result, the dimensional variation of the fitted portion 31P can be uniformly absorbed in the axial direction X while firmly fixing the intermediate member 4 to the fitted portion 31P.

Therefore, it is possible to manufacture the telescopic shaft 1P that can reduce the cost and improve the slidability between the male-side shaft 2 and the female-side shaft 3.
Further, since the telescopic shaft 1P can be manufactured in a short time by the manufacturing method including the press-fitting step described above, it is possible to suppress an increase in the manufacturing cost of the telescopic shaft 1P.
Further, since the resin 73 melted by being pressed against the fitted portion 31P can fill the gap S (see FIG. 8) between the fitted portion 31P and the intermediate member 4P, the fitting portion 31P has a Can further absorb dimensional variations.

In addition, in the press-fitting process, the intermediate member 4P may be press-fitted between the fitting shaft portion 21 and the fitted portion 31P, so that the gap between the intermediate member 4P and the fitting shaft portion 21 may be reduced. it can.
The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims.

1; 1P ... Expansion / contraction shaft, 2 ... Male shaft, 2a ... One end, 3 ... Female shaft, 3a ... One end, 4; 4P ... Intermediate member, 4c ... Outer surface, 5 ... Fixing member, 6 ... Welding layer, 21 ... Fitting shaft portion, 31; 31P ... Fitted portion, 33 ... Through hole, 35 ... Hole, 43 ... Recessed portion, 46 ... Divided body, 55 ... Interposed portion, 72 ... Resin, 73 ... Resin, X ... Axial direction , Y ... orthogonal direction

Claims (5)

A male shaft with a fitting shaft at one end,
A female side shaft having a hollow fitted portion at one end, wherein the fitted portion is fitted so as to be relatively movable with the fitting shaft portion,
Including an intermediate member interposed between the fitting shaft portion and the fitted portion,
In the fitted portion, a through hole that penetrates the fitted portion from the inner surface to the outer surface is formed,
The intermediate member is provided with a recess at least in a region facing the through hole,
Further comprising a fixing member that is filled from the through hole into the recess and fixes the intermediate member to the fitted portion,
When the fitting shaft portion and the fitted portion are relatively moved, the fitting shaft portion slides with respect to a surface of the intermediate member on the fitting shaft portion side ,
Part of the fixing member is a portion of the surface of the intermediate member on the side of the fitted portion that is displaced from the recess in the axial direction or the circumferential direction of the fitting shaft portion and the inner surface of the fitted portion. A telescopic shaft characterized by being interposed between them . A male shaft with a fitting shaft at one end,
A female side shaft having a hollow fitted portion at one end, wherein the fitted portion is fitted so as to be relatively movable with the fitting shaft portion,
Including an intermediate member interposed between the fitting shaft portion and the fitted portion,
In the fitted portion, a hole recessed from the inner surface of the fitted portion toward the outer surface is formed,
The intermediate member includes a welding layer that spreads to a boundary surface with the fitted portion and a part of the intermediate member enters the hole, and is welded to the fitted portion.
The telescopic shaft, wherein the fitting shaft portion slides with respect to a surface of the intermediate member on the fitting shaft portion side when the fitting shaft portion and the fitted portion move relative to each other. . The expandable shaft according to claim 1 or 2 , wherein the intermediate member includes a pair of divided bodies sandwiching the fitting shaft portion in a direction orthogonal to an axial direction of the fitting shaft portion. A male shaft having a fitting shaft portion at one end, a hollow fitted portion at one end, and a hole formed in the inner surface of the fitted portion, wherein the fitted portion is the fitting shaft. A method of manufacturing a telescopic shaft, comprising: a female-side shaft fitted so as to be relatively movable with a portion; and a resin intermediate member interposed between the fitting shaft portion and the fitted portion,
By pressing the intermediate member between the fitting shaft portion and the fitted portion in a state where ultrasonic vibration is transmitted to the intermediate member externally fitted to the fitting shaft portion. A step of press-fitting the intermediate member between the fitted portion and the fitting shaft portion while melting the resin of the portion of the intermediate member that is pressed against the fitted portion,
And a step of curing the melted resin, the method of manufacturing a stretchable shaft. The step of press-fitting the intermediate member between the fitted portion and the fitting shaft portion includes a step of letting the molten resin into a hole formed in the inner surface of the fitted portion. The method for manufacturing an expandable shaft according to claim 4 , which is characterized in that.

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