JP5694720B2 - Manufacturing method of grooved bolt - Google Patents

Description

  The present invention relates to a method for manufacturing a grooved bolt in which a screw is rolled on the screw forming portion of a bolt material in which a groove is provided in a screw forming portion of a shaft portion.

  The grooved bolt is used when, for example, an oil pipe used as an oil flow path of a vehicle automatic transmission or the like is fixed to a fixing part of a case or the like via a union part, and the groove is an oil flow path. Configure.

  As a manufacturing method of this type of grooved bolt, conventionally, for example, in Patent Document 1, a plurality of grooves are provided at positions where the outer periphery of the shaft portion of the bolt is equally divided, and any rolling roll is provided in this groove. A method has been disclosed in which a threaded portion is formed by arranging a rolling roll so that the shaft portion can always be sandwiched by a plurality of rolling rolls even when the thread is fitted.

  Further, in Patent Document 2, a non-cylindrical portion is formed using a non-cylindrical portion processing die on a grooved bolt material in which a groove is formed in a bolt shaft portion, and after the processing is completed, screw rolling is performed. A manufacturing method of a grooved bolt in which a screw part is formed using a die is disclosed.

Japanese Patent Laid-Open No. 9-4622 JP 62-244543 A

  In Patent Document 1, since it is difficult to continuously supply a grooved bolt material to a rolling roll device, a large amount of screw parts cannot be processed in a short time, resulting in low productivity. There is.

  Moreover, in the said patent document 2, since it is necessary to form a non-cylindrical part by another process, there exists a problem that productivity is low.

  The present invention has been made in view of the above-described conventional situation, and provides a method for manufacturing a grooved bolt that can ensure screw accuracy and can improve productivity without requiring an additional step. The issue is to provide.

The invention according to claim 1 has a head, a neck lower part following the head and a screw forming part extending to the shaft end following the neck lower part, and a groove extending in the axial direction is recessed in the screw forming part. In the method for manufacturing a grooved bolt in which a screw is formed on the screw forming portion by a rolling die of a bolt material including a shaft portion, the neck lower portion includes a bolt grip portion formed so as to form an annular concave groove. A continuous recess that is continuous with the lower edge of the large-diameter portion is formed at the upper end of the groove. Is in communication with the bolt grip part,
The rolling die is provided with a guide forming die and a screw forming die each having a forming portion and a finishing portion following the forming portion, and the lower portion of the neck is sandwiched by the forming portion of the guide forming die. By forming the bolt grip portion at the lower neck portion, the screw forming die forming portion starts forming the screw at the screw forming portion, and then the guide forming die finish portion at the bolt grip portion. It is characterized in that the screw is finished by the finished portion of the screw forming die by using the bolt grip portion as a guide by pinching and rolling.

  According to the present invention, the screw material is screwed with the screw forming die while the lower part of the bolt material is nipped and rolled with the guide forming die, so that the bolt material is rolled evenly without being affected by the groove. Therefore, an appropriate screw shape can be secured, and the screw machining accuracy can be secured.

  In addition, since the guide forming die has a function to form a bolt grip portion, the bolt material can be easily rolled while being pinched, and it is special for supplying the bolt material to the rolling die and holding the bolt material. Therefore, it is possible to improve productivity and suppress an increase in cost.

It is a cross-sectional side view which shows the use condition of the grooved bolt which concerns on Example 1 of this invention. It is a front view of the rolling die for manufacturing the said bolt with a groove | channel. It is sectional drawing (III-III sectional view taken on the line of FIG. 2) of the said rolling die. It is sectional drawing (IV-IV sectional view taken on the line of FIG. 2) of the guide formation die which comprises a part of said rolling die. It is a perspective view for demonstrating the manufacturing method of the said bolt with a groove | channel. It is a cross-sectional front view which shows the state by which the grooved bolt was clamped by the said rolling die in the manufacture process of the said grooved bolt. It is a cross-sectional side view which shows the use condition of the grooved bolt which concerns on Example 2 of this invention. It is a front view of the rolling die | dye which concerns on the said Example 2. FIG. It is sectional drawing (the IX-IX sectional view taken on the line of FIG. 8) of the rolling die concerning the said Example 2. It is a top view which shows the modification of the rolling die based on the said Example 1. FIG. It is sectional drawing (the XI-XI sectional view taken on the line of FIG. 10) of the rolling die concerning the said modification.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 6 are views for explaining a method for manufacturing a grooved bolt according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the grooved bolt 1 according to the first embodiment is used for attaching a union part 2 fixed to an oil pipe 2d to a fixed part 4 such as a transmission case with a gasket 3 interposed therebetween. ing. The union portion 2 is formed with an insertion hole 2a into which an oil pipe 2d is inserted and fixed, a through hole 2b into which the grooved bolt 1 is inserted, and a recess 2c that forms an oil flow path.

The grooved bolt 1 is composed of a head portion 5 and a shaft portion 6 forming a hexagonal bolt head. The shaft portion 6 has a neck lower portion 8 following the head portion 5 and a screw forming portion 7 extending from the neck lower portion 8 to the shaft end 6b. The lower neck portion 8 is composed of a large diameter portion 8a located on the head 5 side and a small diameter portion 8b having a smaller diameter. And wherein the large-diameter portion 8a is bolt grip portion 8c is formed so as to form an annular concave groove.

The screw forming portion 7 is formed with a screw 7a, and grooves 9 and 9 are recessed at a position at which the outer peripheral surface of the screw 7a is divided into two equal parts, that is, at positions facing each other across the axis. The groove 9 has a length that reaches the small diameter portion 8b over the entire axial length of the screw forming portion 7. A continuous recess 9a is formed at the upper end of the groove 9 so as to allow the groove 9 to continue to the lower edge of the large-diameter portion 8a. Recess 2c of the union part 2, the bolt grip portion 8c and surrounds opening the relatively large gaps the continuous recess 9a, thereby the oil passes through the recess 2c from the groove 9 and the continuous recess 9a It circulates through the oil pipe 2d without any trouble.

  The gasket 3 includes an upper gasket portion 3 a interposed between the head portion 5 and the upper surface of the union portion 2, and a lower portion interposed between the lower surface of the union portion 2 and the mounting surface 4 a of the fixing portion 4. It has a U-shaped cross section having a gasket portion 3b and a connecting portion 3c for connecting both gasket portions. The gasket 3 prevents the oil from leaking.

  For the manufacture of the grooved bolt 1, a rolling die 10 comprising a pair of fixed die 10a and movable die 10b shown in FIGS. 2 to 5 is used. FIG. 2 shows the movable die 10b, and the fixed die 10a is symmetrical with the movable die 10b.

  Each of the fixed die 10a and the movable die 10b includes a guide forming die 11 and a screw forming die 12 connected and fixed thereto.

  The guide forming die 11 has a substantially rectangular parallelepiped shape, and includes a molding part 11a, a finishing part 11b following the molding part 11a, and a relief part 11c following the finishing part 11b.

  On the surface 11d of the guide forming die 11 facing the counterpart die, a convex strip portion 11e is formed so as to be located at a substantially central portion in the height direction of the facing surface 11d. The protruding line portion 11e has a curved surface in a cross-sectional view and slightly protrudes from the facing surface 11d, and the height of the left end portion 11e ′ of FIGS. 2 and 4 of the molded portion 11a is zero. From here, it becomes gradually higher toward the finishing portion 11b, is set to the same height in the finishing portion 11b, and is gradually lowered in the escape portion 11c (see FIG. 4).

  The screw forming die 12 has a substantially rectangular parallelepiped shape, and continues to the initial relief portion 12a, the molded portion 12b following the initial relief portion 12a, the finishing portion 12c following the molded portion 12b, and the finishing portion 12c. And an escape portion 12d. A screw forming tooth 12f is formed on the surface 12e of the screw forming die 12 facing the counterpart die over the entire length from the initial escape portion 12a to the escape portion 12d. In the initial escape portion 12a and the escape portion 12d, the height of the screw forming teeth is slightly lower than the adjacent portion.

  A method for manufacturing the grooved bolt 1 using the rolling die 10 will be described.

  First, a bolt material 15 formed by forging a steel rod or the like is prepared. The bolt material 15 has a head portion 5 and a shaft portion 6. As described with reference to FIG. 1, the shaft portion 6 includes a neck lower portion 8 following the head portion 5, and a screw forming portion 7 extending to the shaft end following the neck lower portion 8. A groove 9 is recessed at a position that bisects the outer peripheral surface 7b of the screw forming portion 7, and a continuous recess 9a is formed.

  FIG. 5 shows that the bolt material 15 is changed to a bolt material 15 ′ in a state where the formation of the bolt grip portion 8c ′ and the screw 7a ′ has progressed, and the formation of the bolt grip portion 8c and the screw 7a is completed. The state which changes to the attached bolt 1 is shown.

  First, the bolt material 15 is clamped with the large diameter portion 8a of the neck lower portion 8 between the end portions 11e 'and 11e' of the guide forming dies 11 and 11 of the fixed and movable dies, and the screw forming portion. 7 is held between the initial relief portions 12a and 12a of the screw forming dies 12 and 12 of the fixed and movable dies.

  Subsequently, the movable die 10b is moved relative to the fixed die 10a to the left in FIG. Along with this movement, the bolt grip portion 8c is started to be recessed in the large diameter portion 8a by the forming portion 11a portion of the protruding portion 11e of the guide forming die 11, and at the same time, the screw forming die of the screw forming die 12 is formed. The screw 7a is started to be formed by the portion 12b. When the movable die 10b is further relatively moved, the bolt grip portion 8c is sandwiched and rolled by the finishing portion 11b of the guide forming die 11, and the bolt grip portion 8c is used as a guide. The finishing process of the screw is performed at the finishing portion 12 c of the screw forming die 12. Then, the grooved bolt 1 in which the screw 7 a is formed is discharged from the rolling die 10 through the escape portion 11 c of the guide forming die 11 and the escape portion 12 d of the screw forming die 12.

In the first embodiment, the bolt material 15 is threaded with the screw forming die 12 while the neck lower portion 8 in which the groove 9 is not formed is sandwiched and rolled by the guide forming die 11. 15 can be evenly rolled without being affected by the groove 9, an appropriate screw shape can be ensured, and screw machining accuracy can be ensured. Further, the Rukoto to the angular spacing of the grooves 9, 9 180 degrees, since there is provided in a position facing each other across the axis, can also eliminate the effect of the groove 9 in the threaded from this point, screw machining accuracy Can be secured.

  Further, since the bolt grip portion 8c is formed by the guide forming die 11, the bolt material 15 can be rolled while being easily and securely held without being affected by the groove 9, and the rolling die of the bolt material 15 can be rolled. No special equipment or the like is required for the supply to 10 and the holding of the bolt material 15, so that productivity can be improved and an increase in cost can be suppressed.

  7 to 9 are views for explaining a method for manufacturing a grooved bolt according to the second embodiment of the present invention. In the figure, the same reference numerals as those in FIGS. 1 to 6 denote the same or corresponding parts.

  As shown in FIG. 7, the through-hole 2b of the union part 2 which concerns on the present Example 2 has penetrated up and down with the same diameter, and does not have the recessed part 2c in Example 1. FIG. An oil hole 2e is opened in the through hole 2b.

  Further, in the grooved bolt 1 according to the second embodiment, the bolt grip portion 8d extends from the lower portion of the large diameter portion 8a of the neck lower portion 8 to the lower portion of the small diameter portion 8b, that is, the screw 7a. It is formed close to the side. The minimum diameter portion of the bolt grip portion 8d is formed to have a smaller diameter than the outer diameter portion of the screw 7a. A continuous recess 9a formed at the upper end of the groove 9 communicates with the bolt grip portion 8d, and the bolt grip portion 8d communicates with an oil hole 2e opened in the through hole 2b.

  In this way, in the second embodiment, the groove 9 communicates directly with the oil hole 2e through the continuous recess 9a and the bolt grip portion 8d. Therefore, in the second embodiment, as described above, the first embodiment 1 The concave portion 2c in FIG.

  For manufacturing the grooved bolt 1, a fixed die 10 a and a movable die 10 b shown in FIGS. 8 and 9 are used. The fixed and movable dies 10a and 10b are symmetrical. The fixed and movable dies 10a and 10b have substantially the same structure as the fixed and movable dies in the first embodiment, and the protruding strip portion 11f of the guide forming die 11 is located at the position where the bolt grip portion 8d is formed. The only difference is that the guide forming die 11 is formed near the lower end of the facing surface 11d.

  In the same manner as in the first embodiment, by rolling the bolt material 15 while holding the neck lower portion 8 between the guide forming dies 11, 11, the guide forming dies 11, 11 form the bolt grip portion 8d. Meanwhile, the screw forming dies 12, 12 form the screw 7a. The bolt grip 8d communicates with the groove 9 through a continuous recess 9a.

  As described above, in the second embodiment, the bolt grip portion 8d having a diameter smaller than the outer diameter of the screw 7a of the screw forming portion 7 is formed on the neck lower portion 8 of the grooved bolt 1 by the guide forming die 11. Therefore, the bolt grip portion 8d communicates with the groove 9 via the continuous recess 9a. Therefore, it is not necessary to form the concave portion 2c as in the first embodiment in the union portion 2, it is only necessary to form a straight through hole 2b having the same diameter, the processing of the union portion 2 is easy, and productivity is improved. Can be improved and cost increase can be suppressed.

  In the first embodiment, the case where the rolling die 10 is a flat die having a substantially rectangular parallelepiped shape has been described. However, the rolling die of the present invention is a rotary die 10 ′ shown in FIGS. It may be. The rotary die 10 'is composed of a fan-shaped fixed die 10a' and a cylindrical rotary die 10b '. The fixed-side and rotary-side dies 10a 'and 10b' are respectively provided with a guide forming die 11 'and a screw forming die 12'. While the bolt grip portion is formed with the protruding portions 11e of 11 'and 11', the screw forming portions 12 'and 12' are threaded into the screw forming portion.

  Even when thread rolling is performed using the rotary die 10 ', an appropriate screw shape can be secured, screw machining accuracy can be secured, productivity can be improved, and cost increase can be suppressed.

  In addition, although the example which provided the two grooves 9 was demonstrated in the said Example, the groove | channel in this invention is not limited to the said Example, For example, when setting it as a 90 degree space | interval, an axis line is provided. Four grooves can be provided at positions opposed to each other. Thus, by providing a groove in the position which opposes, the influence of the groove | channel in screw processing can be eliminated and the deterioration of the screw processing precision by a groove | channel can be prevented.

DESCRIPTION OF SYMBOLS 1 Grooved bolt 5 Head part 6 Shaft part 7 Screw formation part 7a Screw 7b Outer peripheral surface 8 Neck lower part 8c, 8d Bolt grip part 9 Groove 10 Rolling die 11 Guide formation die 12 Screw formation dice 11a, 12b Molding Part 11b, 12c Finishing part 15 Bolt material

Claims (1)

A bolt material comprising a head, a neck lower part following the head, and a shaft part having a thread forming part extending over the shaft end following the neck lower part and having a groove extending in the axial direction in the screw forming part. In the manufacturing method of the grooved bolt for forming a screw by a rolling die in the screw forming portion,
The lower neck portion has a large diameter portion having a bolt grip portion formed so as to form an annular concave groove, and a small diameter portion having a smaller diameter than the large diameter portion. A continuous recess that is continuous with the lower edge of the large-diameter portion, and the continuous recess communicates with the bolt grip portion,
The rolling die is provided with a guide forming die and a screw forming die each having a forming part and a finishing part following the forming part,
A bolt grip part is formed at the lower part of the neck by pinching and rolling the lower part of the neck at the forming part of the guide forming die, and a screw is started to be formed at the screw forming part at the forming part of the screw forming die. Thereafter, the bolt grip portion is sandwiched and rolled by the finish portion of the guide forming die, and the screw finish processing is performed at the finish portion of the screw forming die using the bolt grip portion as a guide. A method for manufacturing a grooved bolt.

Images