JPH0921411A - Bolt with flow passage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the bolt structure at a low production cost, maintaining the function of a conventional bolt with insertion hole for flowing the fluid such as oil. SOLUTION: In a bolt having a header part 11 and a shaft part 22 and provided with a screw forming part in the surface of the shaft part 11, at least one or more of flow passages 33 having the predetermined lead angle are formed in the surface of the shaft part 22 at a depth deeper than the thread groove of the screw forming part over from the shaft part end to the predetermined position. Since the flow passage 33 is formed in any one of process of a cold forging process for forming a basic shape and a form rolling process for forming a screw, a cutting process for forming an insertion hole in the conventional bolt with insertion hole is not required, and the production cost can be remarkably lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolt having a flow path used for fixing the ends of pipes such as fuel hoses, oil hoses and brake hoses for automobiles.

[0002]

2. Description of the Related Art Conventionally, as a bolt having a mechanism for allowing a fluid such as oil to pass, there is a bolt with an insertion hole having an insertion hole communicating with a T-shape in the shaft portion of the bolt. As shown in FIG. 6, in the bolt composed of the header portion 1 and the shaft portion 2, a vertical hole 3 extending from the end side of the screw forming portion to the cylindrical portion where the screw is not formed is provided in parallel with the axis line. A horizontal hole 4 that penetrates the shaft portion 2 perpendicularly to the vertical hole 3 is provided so as to communicate with the vertical hole 3, thereby forming an insertion hole that communicates in a T-shape.

Such a bolt with an insertion hole having an insertion hole communicating with a T-shape is used to form a pipe joint, as shown in FIG. 7, for example. The bolt with an insertion hole is fastened to the first piping member 5 whose inner diameter is threaded at the thread forming portion. In addition, the bolt with an insertion hole is configured such that the end portion 6 of the second piping member that opens in a ring shape is sandwiched through the gaskets 7 and 7'at a position that covers the lateral hole 4 of the cylindrical portion where the screw is not formed. To conclude. Therefore, the first piping member 5
Through the vertical hole 3 of the bolt with an insertion hole, the horizontal hole 4, the end 6 of the second piping member, and the second piping member.

As described above, the bolt with the insertion hole has a function as a fastening member for the two piping members, and also has a function as a part of piping through which the fluid passes.

[0005]

By the way, in the conventional bolt with an insertion hole, as a method of manufacturing the bolt, the first step of forming the basic shape of the header portion and the shaft portion of the bolt by cold forging, In addition, a second step of forming an insertion hole by cutting with a drilling machine or the like, and finally a third step of forming a screw forming portion by rolling to complete a bolt with an insertion hole are required.

That is, as compared with a method of manufacturing a normal bolt having no insertion hole, the method of manufacturing a bolt with an insertion hole includes a second step of cutting by a cutting machine such as a drilling machine for forming the insertion hole. Needing extra. In addition, since the second step is a cutting process, it requires much more time to manufacture and a higher production cost than the first step by cold forging and the third step by rolling. Attached bolts were more expensive than ordinary bolts.

Therefore, an object of the present invention is to achieve a bolt structure with a low production cost while maintaining the function of a conventional bolt with an insertion hole.

[0008]

As a means for solving the above problems, the present invention provides a bolt having a header portion and a shaft portion, and a thread forming portion provided on the surface of the shaft portion. In addition, at least one flow path deeper than the thread groove and having a predetermined lead angle is formed from the end of the shaft portion to a predetermined position.

[0009]

According to the above-mentioned means, the function as a pipe for passing the lubricating oil of the bolt is achieved by forming a flow path deeper than the thread groove on the surface of the shaft portion of the bolt from the end portion of the shaft portion to a predetermined position. Since such a flow path can be formed either in the step of forming a basic shape by cold heading or in the step of forming a screw by rolling, it can be formed like a conventional bolt with a through hole. In addition, a cutting process for forming the insertion hole is not required.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a side view showing a bolt with a flow path according to a first embodiment of the present invention. The passage bolt has a header portion 11 and a shaft portion 22. The shaft portion 22 has a surface
The thread forming portion 221 is provided from the end of the shaft portion to a predetermined position, and the cylindrical portion 222 is provided from the predetermined position to the seat surface of the header portion.

The shaft portion 22 has a channel 33 formed on its surface deeper than the thread groove. The flow path 33 is formed from the screw forming portion 221 to a predetermined position of the cylindrical portion 222 where the screw is not formed. This predetermined position is, as shown in FIG. 5, when a bolt with a flow path is used for a pipe joint,
If the flow path 33 is formed up to an arbitrary position where the end 6 of the second piping member that opens in a ring shape from the shaft end covers the bolt with flow path, conventional lubricating oil can be used. It functions as an insertion hole through which it passes.

Further, as shown in FIG. 1, the flow path 33 is not formed in parallel with the axis of the shaft portion 22, but is formed with a predetermined lead angle α. This is indispensable for manufacturing the bolt with a flow path in the same manner as a normal bolt in two steps, that is, the first step of forming the basic shape of the bolt by cold forging and the second step of rolling. Is a requirement. That is, when the flow path 33 is formed in the first step by cold heading, when the flow path is formed parallel to the axis during the second step by rolling for thread formation, When the rolling die is pressed, the die falls into the flow path, and it becomes impossible to maintain a constant rolling pressure, so that accurate screw formation cannot be performed. Further, when the flow path 33 is formed in the second step by rolling, it is necessary to maintain a constant rolling pressure, and therefore a flow path parallel to the axis cannot be formed.

In the first embodiment, as shown in the bottom view of FIG. 2, four flow paths 3 are formed at every 90 ° from the bottom surface of the shaft portion 22.
3 are formed. Then, the lead angle α of the flow path 33
When the flow path length is L and the radius of the shaft portion 22 is R,

[Equation 1] The relational expression of is satisfied. This will form the passage 33 once around the screw.
Therefore, in the second step of rolling, the moving die and the fixed die that sandwich the bolt with the flow path always meet the flow path 33 at one point, and a more stable rolling pressure is maintained. Therefore, it is possible to form a highly accurate and accurate screw.

FIGS. 3 and 4 show a second embodiment of the present invention, showing a bolt with flow passages having six flow passages formed therein. In order to maintain a more stable rolling pressure with respect to this bolt with flow passage, as in the first embodiment, when the lead angle α of the flow passage 33, the flow passage length L, and the effective diameter R of the screw are set,

[Equation 2] The relational expression of is satisfied.

More generally, in the case where n flow paths are formed, in order to maintain a more stable rolling pressure,

(Equation 3) Is to satisfy the relational expression of.

By the way, in the first and second embodiments, the lead angle α of the flow path 33 is about 75 °.
This is due to a manufacturing constraint that, when the flow path 33 is formed in the first step by cold heading, it becomes difficult to form the flow path if the lead angle is reduced.

The lead angle α of about 75 ° is a manufacturing constraint when the flow path 33 is formed in the first process by cold forging, and the screw is used in the second process by rolling. When forming the flow path 33 along with the formation, there is no such restriction on the lead angle.

If the sum of the cross-sectional areas of the plurality of flow paths 33 shown in FIGS. 2 and 4 is equal to the cross-sectional area of the conventional insertion hole, it is the same as the conventional insertion hole as piping for lubricating oil or the like. Can perform the function of.

FIG. 5 shows the bolt with flow passage according to the first embodiment of the present invention used for forming a conventional pipe joint.

The bolt with an insertion hole is fastened to the first piping member 5 having a threaded inner diameter at the thread forming portion. Channel 33
Is formed deeper than the thread groove, so that a piping path is secured between the flow path 33 and the inner wall of the first piping member 5 even in the tightened state. Further, the bolt with the flow passage is fastened by sandwiching the end portion 6 of the second piping member opened in a ring shape at a position covering the end portion on the cylindrical portion side of the flow passage 33 via the gaskets 7 and 7 '. doing. Therefore, the fluid flowing through the first piping member 5 passes through the piping path formed between the flow path 33 and the inner wall of the first piping member 5, reaches the end portion 6 of the second piping member, and then the second piping member. Flow to.

In this way, the bolt with flow passage does not require a cutting step for forming the flow passage in its manufacturing process, and a basic shape is formed by cold forging which is a normal bolt manufacturing process. The flow path can be formed at the same time in any one of the step 1 and the second step of forming the screw by rolling. Therefore, it becomes possible to manufacture a bolt having the same function as the bolt with an insertion hole at a manufacturing cost of a normal bolt having no insertion hole.

[0023]

As described above, the bolt with flow passage of the present invention functions as a pipe for passing lubricating oil of the bolt,
This can be achieved by forming a flow path on the surface of the bolt shaft portion that is deeper than the thread groove and has a predetermined lead angle. Therefore, the manufacturing method of the bolt with a flow path is different from the conventional bolt with a through hole, because the cutting step of cutting using a cutting machine such as a drilling machine to form the through hole is eliminated, and a normal bolt manufacturing process. Since it becomes possible to form the flow path at the same time in any of the first step of forming the basic shape by cold forging or the second step of forming the screw by rolling, the conventional through hole It has an excellent effect that a highly productive bolt can be manufactured while retaining the function of the attached bolt.

[Brief description of drawings]

FIG. 1 is a side view of a bolt with a flow path showing a first embodiment of the present invention.

FIG. 2 is a bottom view of the bolt with flow path showing the first embodiment of the present invention.

FIG. 3 is a side view of a bolt with a flow path showing a second embodiment of the present invention.

FIG. 4 is a bottom view of the bolt with flow passage showing the second embodiment of the present invention.

FIG. 5 is a partial cross-sectional view showing a pipe joint to which the present invention is applied.

FIG. 6 is a side view showing a conventional bolt with an insertion hole.

FIG. 7 is a partial cross-sectional view showing a conventional through hole bolt applied to a pipe joint.

[Explanation of symbols]

 11 ... Header part 22 ... Shaft part 221 ... Screw forming part 222 ... Cylindrical part 33 ... Flow path

Claims (1)

[Claims] 1. A bolt having a header portion and a shaft portion, wherein a thread forming portion is provided on a surface of the shaft portion, the surface of the shaft portion having a predetermined lead angle deeper than a thread groove of the thread forming portion. A bolt with a flow path, characterized in that at least one flow path is formed from an end of the shaft portion to a predetermined position.