JP4687428B2 - Slide joint with slit and manufacturing method thereof - Google Patents

Description

  The present invention relates to a slide joint with a slit, and more particularly to a slide joint with a slit used as an intermediate shaft or the like of a steering device and a method for manufacturing the same.

  The slide joint with slits efficiently transmits the rotation of the steering wheel to the steering gear, and the outer shaft and the inner shaft need to slide relative to each other with a small sliding resistance at the time of adjusting the position of the steering wheel or at the time of collision.

  The slide joint with slit of Patent Document 1 is formed such that the inner diameter of the female serration groove of the outer shaft is the smallest in the axial middle position of the slit and the largest in the open end side of the slit. As a result, the female serration groove of the outer shaft and the male serration groove of the inner shaft are strongly engaged at two positions, the axial middle position of the slit and the open end side position of the slit, so that both torsional rigidity and sliding resistance are achieved. However, in order to improve the steering feeling, it has been desired to further improve the torsional rigidity and bending rigidity of the coupling portion.

JP 2001-74056 A

  It is an object of the present invention to provide a slide joint with a slit that further improves the torsional rigidity and bending rigidity of the joint between the female serration groove of the outer shaft and the male serration groove of the inner shaft.

The above problem is solved by the following means. That is, the first invention has a female serration groove on the inner peripheral surface on one end side in the axial direction, and a plurality of slits in which the end surface on the one end side in the axial direction is opened and the end surface on the other end side is closed. A hollow cylindrical outer shaft, an inner shaft in which a male serration groove that fits and engages with the female serration groove is formed on an outer peripheral surface on one axial end side, and an outer peripheral surface on one axial end side of the outer shaft In the manufacturing method of the slide joint with slit , the outer periphery of the hollow cylindrical material on the one end side in the axial direction is provided. Forming a first drawn portion having a diameter reduced by drawing on the surface, and at equal circumferential positions of the first drawn portion within the range of the first drawn portion, on one end side in the axial direction thereof Open And forming a slit having an open end, forming a female serration grooves on the inner peripheral surface of the first throttle portion, from the open end of the axial end of the slit in the axial end The outer diameter and inner diameter of the outer shaft are reduced by press-fitting a die having an inner diameter hole smaller in diameter than the outer dimension of the outer shaft into the outer peripheral surface of the outer shaft and drawing it over the closed end. Forming a second constriction portion , a tapered truncated cone portion, and a correction punch having a guide cylindrical portion fitted in the female serration groove at the tip thereof, and a female punch in the second constriction portion. by press-fitting the inner peripheral surface of the serration groove and an inner diameter in a free state of the female serration grooves, it is the most small near the closed end of the slit, suited to the open end of the slit As a step of forming the large diameter of the production method of the slotted slide joint, characterized in that it is carried out in this order.

  2nd invention is the slide joint with a slit manufactured by the manufacturing method of the slide joint with a slit of 1st invention.

  In the slide joint with a slit of the present invention, the outer diameter and inner diameter of the outer shaft are reduced from the open end on the one end side in the axial direction to the closed end on the other end side in the axial direction. As an axial interval between the positions where the male serration groove and the male serration groove are strongly engaged, a length substantially the same as the axial length of the slit can be secured. Therefore, it is possible to improve the bending rigidity and torsional rigidity of the joint portion between the outer shaft and the inner shaft.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view sequentially illustrating steps for manufacturing an outer shaft of a slide joint with a slit according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a post-process of FIG. FIG. 3 is a cross-sectional view showing a subsequent step of FIG. 2 and showing a drawing step for reducing the outer diameter and inner diameter of the outer shaft.

  FIG. 4A is a cross-sectional view showing a post-process of FIG. 3 and a process of enlarging the inner diameter of the outer shaft, showing a state before insertion of the correction punch. 4 (2) is a left side view of the outer shaft of FIG. 4 (1). FIG. 5 is a cross-sectional view showing a process of expanding the inner diameter of the outer shaft, and is a cross-sectional view showing a state after inserting the correction punch. FIG. 6 shows the outer shaft after molding and the inner shaft assembled to the outer shaft, (1) is a sectional view showing a state before assembly, and (2) is a sectional view showing a state after assembly.

  1 to 5 show the manufacturing process of the outer shaft. First, as shown in FIG. 1A, a hollow cylindrical material 10 is prepared. Then, in the first step, the first drawn portion 21 is formed by subjecting the outer peripheral surface of one end of the material 10 in the axial direction (left side of FIG. 1 (1)) to diameter reduction processing such as pressing with a press. 1st intermediate material 11 as shown in FIG. 1 (2) is formed.

  Next, as a second step, an annular locking recess 22 is formed by cutting using a lathe or the like on the entire outer periphery of the first intermediate material 11 near the one axial end side (left side in FIG. 1). Thus, the second intermediate material 12 as shown in FIG. 1 (3) is formed.

  Next, as a third step, four slits 3 are formed by punching by a press or machining at equal circumferential positions (90-degree intervals) within the axial range of the first throttle portion 21. Then, the third intermediate material 13 as shown in FIGS. 2 (1A) and (1B) is formed. The number of slits 3 is not limited to four, but may be two, three, five, or more. FIG. 2 (1B) is a left side view of FIG. 2 (1A). The slit 3 has an open end 31 in which an end face on one end side in the axial direction (left side in FIG. 2 (1A)) is opened, and an end face on the other end side in the axial direction (right side in FIG. 2 (1A)) is closed. It has a closed end 32.

  Next, as a fourth step, a female serration groove 4 is formed by broaching on the inner peripheral surface of the first drawn portion 21 of the third intermediate material 13, and the second step as shown in FIG. Four intermediate materials 14 are formed. In addition, the shape of the said 1st aperture | diaphragm | squeeze part 21 after forming this female serration groove | channel 4 becomes a straight shape in which a diameter does not change over an axial direction in the case of broaching. Since the first to fourth steps described above are the same as the manufacturing steps of the outer shaft for the slide joint with slit described in Patent Document 1, detailed description thereof is omitted.

  Next, as a fifth step, the die 5 is press-fitted from one axial end side (the left side of FIG. 3 (1)) of the first throttle portion 21 of the fourth intermediate material 14 shown in FIG. The second drawn portion 23 is formed by drawing on the outer peripheral surface near the one end side in the axial direction of the portion 21 to reduce the outer diameter and the inner diameter of the first drawn portion 21, as shown in FIGS. A fifth intermediate material 15 as shown is formed.

  The second diaphragm 23 is formed from the open end 31 on one end side in the axial direction of the slit 3 to the vicinity of the closed end portion 32 on the other end side in the axial direction of the slit 3. In the embodiment of the present invention, the inner diameter D of the die 5 is set to φ23.8 mm, for example, and the outer diameter d of the first throttle portion 21 is set to φ24.1 mm, for example. The amount by which the inner diameter is reduced is about 0.3 mm in diameter. The axial length L1 of the slit 3 (the length from the open end 31 on one axial end side to the closed end 32 on the other axial end side) is 38 mm, and the axial length L2 of the reduced diameter portion 23 is It is set to 33 mm.

  Next, as a sixth step, the correction punch 6 is made to face the opening of one end in the axial direction of the fifth intermediate material 15 (the end on the open end 31 side of each slit 3 and the left end in FIG. 4 (1)). . A tapered truncated cone part 61 is formed at the tip of the correction punch 6, and the taper angle of the truncated cone part 61 is set to 5 degrees, which is the easiest to correct, but in the range of 1 to 10 degrees. I just need it. Further, a guide cylindrical portion 62 that fits in the female serration groove 4 is formed at the further tip of the truncated cone portion 61.

  By inserting such a correction punch 6 into the tip opening of the fifth intermediate material 15 as shown in FIG. 5, the guide cylindrical portion 62 is fitted into the female serration groove 4 and is smoothly inserted. The inner diameter of the female serration groove 4 is increased by the base 61, and the fifth intermediate material 15 becomes the outer shaft 2 as shown in FIG. 5 and FIG. 6 (1).

  When the front end portion of the correction punch 6 is pushed into the front end opening portion of the fifth intermediate material 15, intermediate portions 33 and 33 existing between the slits 3 and 3 adjacent to each other in the circumferential direction (see FIG. 4 (2)). However, each of the inter-parts 33, 33 is bent outward in the diameter direction around the other axial end (the part connecting the closed ends 32 of the slits 3, 3).

  Each of the intermediate portions 33, 33 has a concave shape in the axial direction on the outer peripheral surface side, and a convex shape in the axial direction on the inner peripheral surface side. As a result, the inner diameter of the female serration groove 4 formed on the inner peripheral surface of each of the intermediate portions 33 and 33 constituting the fifth intermediate material 15 is equal to the inner diameter on the other end side in the axial direction (the slit 3 of the slit 3). The inner diameter 231 near the closed end 32 is the smallest diameter, and the inner diameter on the one end side in the axial direction of the second throttle part 23 (the inner diameter on the open end 31 side of the slit 3) 232 is the largest.

  Next, as shown in FIG. 6, the inner shaft 7 is assembled to the outer shaft 2 formed through the manufacturing steps from the first step to the sixth step. As shown in FIG. 6 (1), the inner shaft 7 has one axial end (right side in FIG. 6) larger in diameter than the other end (left side in FIG. 6), and the female serration groove 4 is formed on the outer peripheral surface thereof. A male serration groove 71 is formed to be fitted inside and engaged. In addition, the holding ring 8 that is externally fitted to the locking recess 22 of the outer shaft 2 is formed in a short cylindrical shape that is continuous over the entire circumference without having a cut.

  As shown in FIG. 6 (2), the male serration groove 71 of the inner shaft 7 is inserted into the female serration groove 4 of the outer shaft 2, and one end side in the axial direction of the second throttle portion 23 (the open end of the slit 3). In the state where the diameter of the (31 side) is elastically contracted, the ring 8 is externally fitted to the retaining recess 22.

  In the state where the inner shaft 7 is assembled to the outer shaft 2, the female serration groove 4 has two axial portions on the other end side inner diameter 231 of the second throttle portion 23 and one end inner diameter 232 in the axial direction of the second throttle portion 23. It is strongly pressed against the outer periphery of the male serration groove 71.

  In the embodiment of the present invention, the engagement position on the other axial end side moves to the closed end 32 side of the slit 3 as compared with the conventional example, so that the female serration groove 4 and the male serration groove 71 are strongly engaged. The space in the axial direction between the portions to be spread is widened, and the length substantially the same as the length of the slit 3 in the axial direction can be secured. Accordingly, the bending rigidity and torsional rigidity of the joint portion between the outer shaft 2 and the inner shaft 7 are improved, and the steering feeling of the steering device can be improved.

  In the embodiment of the present invention, the example applied to the intermediate shaft has been described. However, the present invention is not limited to the intermediate shaft, and may be applied to a steering shaft or the like used in the steering device.

It is sectional drawing which shows the process of manufacturing the outer shaft of the slide joint with a slit of the Example of this invention in order. It is sectional drawing which shows the post process of FIG. FIG. 4 is a cross-sectional view showing a post-process of FIG. 2 and showing a drawing process for reducing the outer diameter and inner diameter of the outer shaft. (1) shows the post-process of FIG. 3, and is a cross-sectional view showing a process of expanding the inner diameter of the outer shaft, showing a state before the correction punch is inserted. (2) is a left side view of the outer shaft of (1). It is sectional drawing which shows the process of expanding the inner diameter of an outer shaft, Comprising: It is sectional drawing which shows the state after correction | amendment punch insertion. The outer shaft after shaping | molding and the inner shaft inserted in an outer shaft are shown, (1) is sectional drawing which shows the state before an assembly | attachment, (2) is sectional drawing which shows the state after an assembly | attachment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Material 11 1st intermediate material 12 2nd intermediate material 13 3rd intermediate material 14 4th intermediate material 15 5th intermediate material 2 Outer shaft 21 1st aperture part 22 Locking recessed part 23 2nd aperture part 231 Axial direction other end side Inner diameter 232 Axial one end inner diameter 3 Slit 31 Open end 32 Closed end 33 Intersection 4 Female serration groove 5 Dies 6 Straightening punch 61 Frustum section 62 Guide cylindrical section 7 Inner shaft 71 Male serration groove 8 Retaining ring

Claims (2)

A hollow cylindrical outer shaft having a female serration groove on the inner peripheral surface on one end side in the axial direction and having a plurality of slits in which the end surface on the one end side in the axial direction is opened and the end surface on the other end side is closed,
An inner shaft in which a male serration groove that fits and engages with the female serration groove is formed on the outer peripheral surface on one end side in the axial direction;
In the manufacturing method of the slide joint with slit, which is fitted on the outer peripheral surface of the outer shaft on one end side in the axial direction of the outer shaft, and includes a restraining ring that elastically reduces the outer diameter on the one end side in the axial direction of the outer shaft.
Forming a first drawn portion reduced in diameter by drawing on the outer peripheral surface on one axial end side of the hollow cylindrical material; and
Forming a slit having an open end that is open on one end side in the axial direction within the range of the first restrictor at the circumferentially equidistant positions of the first restrictor; and
Forming a female serration groove on the inner peripheral surface of the first throttle portion;
A die having an inner diameter hole smaller than the outer dimension of the outer shaft is press-fitted into the outer peripheral surface of the outer shaft from the open end on one end in the axial direction of the slit to the vicinity of the closed end on the other end in the axial direction. Forming the second drawn portion by reducing the outer diameter and inner diameter of the outer shaft by drawing ;
By forming a tapered truncated cone part and, at the tip, a correction punch having a guide cylindrical part fitted into the female serration groove is press-fitted into the inner peripheral surface of the female serration groove in the second throttle part. , an inner diameter in a free state of the female serration groove, at the closed end near the smallest diameter of the slit, the step of forming the large diameter increases toward the open end of the slit
Are performed in this order, and the manufacturing method of the slide joint with a slit characterized by the above-mentioned.   The slide joint with a slit manufactured by the manufacturing method of the slide joint with a slit described in Claim 1.

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