JP3501387B2 - Manufacturing method of grooved bolt - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a method for manufacturing a grooved bolt having a flow passage such as an oil supply passage to the shaft portion.

[0002]

As a conventional slotted bolt of this type having a flow passage such as an oil supply passage of the Related Art bolt shaft portion, the neck lower from the back end of the longitudinal hole bored over around the neck lower portion from the center of the axial end surface It is common to have lateral holes drilled over the outer surface of the machine. However, such a flow passage requires labor for drilling and is inaccurate, and burrs are generated during drilling, so removal work is required. However, there is a problem that it is difficult to mass-produce inexpensively.

In order to solve such a problem, a grooved bolt in which a groove-shaped flow passage reaching the shaft end is provided on the outer surface of a screw shaft portion mainly composed of a bolt has been studied, but such a grooved bolt is a screw thread. The peaks of the mountain-shaped end faces facing the groove-shaped flow paths become edges by cutting the peaks in the groove-shaped flow paths without being continuous,
Not only the screwing resistance is great when screwing into the tightened member, but this edge acts as a tap to scrape the tightened member, and the generated chips are mixed into the oil, which is a fatal defect as an oil supply path. May occur, which has been a bottleneck for practical use.

[0004]

The inventors of the present invention [0006] is to solve is the production of small grooves with bolts the screwing resistance on top that can be manufactured easily and at low cost mass production to solve the above-mentioned problems To provide a method.

[0005]

The present invention which has solved the above problems BRIEF SUMMARY OF THE INVENTION The shaft portion outer periphery of the bolt blank groove shaped flow path for the opening edge and convex arc curved over the shaft end from the neck lower part of the ball Rutoburanku And a plurality of rolls are provided at positions where the bolts are evenly divided, and a thread portion is rolled onto the shaft portion by means of rolling rolls arranged at equal intervals around the shaft portion of the bolt blank. A method for manufacturing a grooved bolt, which comprises a rolling process and a rolling process used in the rolling process.
The number of rolls is 3 or more and the number of grooved channels is the number of rolling rolls.
Or the number of rolling rolls
Is an odd number when the number of grooved channels is even
When the number of flow passages is an odd number, the number of rolling rolls used in the rolling process is set to a plurality of rolling rolls even when the rolling rolls fit into any of the groove-shaped flow passages. be characterized in that as thread rolling is performed in pressure contact with the shaft portion
That is also the in.

[0006]

[Action]

According to the method of manufacturing grooved bolt of the invention, you rolling the screw part in a well-known rolling techniques on top a brief molding a groove-like passage in a well-known plastic working method or cutting method can and child. That is, even when the rolling roll is fitted into one of the groove-shaped flow passages during rolling, a plurality of rolling rolls are not always fitted into the groove-shaped flow passage and are pressed against the bolt shaft portion. As a result, the torque of the bolt shaft is maintained and smooth thread rolling is possible, and the part that causes thread groove breaks and increases screwing resistance is opened in the previous step of forming the grooved channel. If the edge is formed into a convex arcuate curved surface, the top of the mountain-shaped end portion becomes a convex arcuate curved surface even after rolling, and steps such as edge removal are not required, and the manufacturing cost can be significantly reduced.

[0008]

Next, a bolt manufactured by the method for manufacturing a grooved bolt of the present invention will be described in detail based on the embodiment shown in FIGS. The shaft portion 2 following the head portion 1 is composed of a neck lower portion 21 having a required length and a screw shaft portion 22 formed with a screw thread, and further, on the outer surface of the shaft portion 2, at least a portion of the screw shaft portion 22 has a shaft. A plurality of groove-shaped flow paths 3 reaching the ends are provided at equal intervals. As shown in FIG. 1 (B), FIG. 2 and FIG. 3, the groove-shaped channel 3 corresponds to one or both of the groove edge portions corresponding to the opening edge of the groove portion 31 having a substantially semicircular or U-shaped cross section, that is, The angled end face 3 facing the groove-shaped flow path 3 becomes a break in the thread formed on the screw shaft portion 22.
The top of 2 is formed on the convex arcuate curved surface 33.

The convex arcuate curved surface 33 is normally formed on both edges of the groove 3 as shown in FIG. 1, but the purpose is to reduce the screwing resistance. Therefore, as shown in FIGS. 2 and 3, only one of the sides facing the screw-in rotation direction may be formed on the convex arcuate curved surface 33.

The radius of curvature of the convex arcuate curved surface 33 is not particularly limited as long as it reduces the screwing resistance, but the effect is remarkable when the M10 bolt defined by JIS is 0.5 mm or more. In addition, it is particularly preferable because it is advantageous in manufacturing. Further, it is necessary that the depth of the groove-shaped channel 3 is deeper than the root of the thread groove so as to secure the fluid passage. The shape of the groove-shaped flow passage 3 is not particularly limited as long as it serves as a fluid passage, but it is preferable that the groove bottom has an arc shape so as to be suitable for plastic working in terms of production efficiency.

Next, an embodiment of the method for manufacturing the grooved bolt of the present invention will be described with reference to FIG. First, a bolt blank in which a screw thread is not yet formed on the shaft portion following the head is prepared, and two groove-shaped channels 3a and 3b are formed on the surface of the shaft portion 2 at positions where the outer circumference of the shaft portion is equally divided. As described in 1), it is formed by a well-known plastic working method or cutting method, or is formed at the same time when the bolt blank is pressed. Then, as shown in FIG. 4, this bolt blank is pressure-welded by rolling rolls 4a, 4b, 4c of three roll rolling machines which are evenly arranged at 120 degree intervals around the shaft portion 2 to form the bolt blank. Rotate. In this case, as shown in FIG.
When the rolling roll 4a coincides with a certain time, the rolling roll 4a among the rolling rolls 4a, 4b, and 4c fits into the groove-like flow path 3a and loses its rotational force. Since the two rolling rolls 4b and 4c are still in pressure contact with the shaft portion 2 and retain the rotational force, the threaded shaft portion 23 is always smoothly rolled.

As described above, even when any one of the rolling rolls 4a, 4b, 4c fits into any of the groove-like flow paths 3a, 3b and loses the rotational force, the other two rolls are pressed against the shaft portion 2. Although smooth screw shaft portion rotating force is retained so that has that is is to be rolled, the number of rolling rolls used for the rolling process for this, one of the groove-like passage Even when the rolling rolls are fitted, it is necessary to always have a plurality of rolling rolls in pressure contact with the shaft portion to perform thread rolling, and for that purpose, the number of rolling rolls is 3 or more and the groove is The number of flow passages can be set to a number excluding a multiple (including the same number) of the number of rolling rolls, but in order to achieve the desired purpose by increasing the rolling effect with the smallest number of rolling rolls. , When the number of rolling rolls is an odd number when the number of grooved channels is an even number, and when the number of grooved channels is an odd number The even number.

[0013]

As is apparent from the above description, the present invention
With the grooved bolt manufacturing method, it is possible to reduce the screwing resistance so that insufficient screwing does not occur even at a predetermined screwing torque, and the top of the end face works as a tap when screwing into the member to be tightened. It is possible to mass-produce inexpensive bolts without scraping the members to be fastened and cutting chips when screwing in, and to keep multiple rolling rolls forced to rotate the bolt shafts. Therefore, there is also an advantage that it is not necessary to forcibly rotate the bolt blank other than the rolling roll. Accordingly, the present invention is a manufacturing <br/> method for producing grooved bolt that solves the conventional problems, its industrial value is made very large.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention, (A) is a front view and (B) is a sectional view of a screw shaft portion.

FIG. 2 is a partially cutaway perspective view showing another embodiment of the groove- shaped channel.

3 is a partially cutaway front view of the groove-like flow path portion shown in FIG.

4 is a conceptual diagram showing the relationship between the volume Rutoburanku and forming roll.

[Explanation of symbols]

1 head 2 shafts 3 groove-shaped channels 4 Rolling roll 21 lower neck 22 Screw shaft 32 Yamagata end face 33 Convex curved surface

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Yoshida 1-8 Takahashi, Oguchi-machi, Niwa-gun, Aichi Prefecture Aoyama Manufacturing Co., Ltd. Oguchi factory (56) Reference JP-A-62-244543 (JP, A) Flat 1-284446 (JP, A) JP 63-190919 (JP, A) Actual open 58-97390 (JP, U) Actual open 53-61428 (JP, U) Actual open 2-116011 (JP , U) Actual Kaihei 7-6513 (JP, U) Actual Kaihei 5-5246 (JP, U) Patent 20291 (JP, C2) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16B 35 / 00 B21H 3/04

Claims (2)

(57) [Claims] 1. A bolt blank extending from the lower neck to the shaft end.
A grooved flow path whose opening edge is a convex arcuate curved surface.
Plural pieces are arranged at positions where the outer circumference of the shaft of the link is evenly divided.
And the shaft of this bolt blank.
With rolling rolls that are evenly spaced around the
With a groove consisting of a rolling process in which the threaded part is rolled onto the shaft part
A method for manufacturing a bolt, which is used in the rolling process.
The number of forming rolls is 3 or more, and the number of grooved channels is rolling
Make sure it is not a multiple of the number of rolls and either groove
Multiple rolls at all times, even when the roll is fitted into the flow path
The roll is pressed against the shaft to perform thread rolling.
A method for manufacturing a grooved bolt, characterized in that 2. The bolt blank extends from the lower neck to the shaft end.
A grooved flow path whose opening edge is a convex arcuate curved surface.
Plural pieces are arranged at positions where the outer circumference of the shaft of the link is evenly divided.
And the shaft of this bolt blank.
With rolling rolls that are evenly spaced around the
With a groove consisting of a rolling process in which the threaded part is rolled onto the shaft part
A method for manufacturing a bolt, which is used in the rolling process.
The number of rolls is odd when the number of grooved channels is even
If the number of grooved channels is an odd number, consider an even number.
And when the rolling roll fits into one of the groove-like channels.
Always, multiple rolling rolls are pressed against the shaft to perform thread rolling.
Manufacture of grooved bolts characterized by
Method.