JP4143738B2 - Bolt and manufacturing die of the bolt - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bolt that is screwed into a female screw while removing a coating thick film and spatter adhering to a nut side.
[0002]
[Prior art]
Conventionally, it has been known that the galling or seizure of bolts and nuts is caused by the bolts being incorporated into the screw holes of the nuts obliquely or by the deposits such as paint thick film or spatter on the screw threads of the nuts. Yes.
In order to prevent such bolts from being obliquely assembled and seizure due to deposits, a countermeasure bolt shown in FIG. The bolt is provided with a plurality of notch-shaped portions (31) from the tip of the threaded portion (3), and the notch-shaped angle (θ) thereafter is opposite to the notch-shaped angle (α) of the inlet. Therefore, it is possible to prevent oblique installation into the nut at the entrance, remove the deposits at the subsequent cutout shape portion, and perform normal fastening without clogging the screw portion (2).
[0003]
[Problems to be solved by the invention]
However, the thick coating film and the like uniformly adhered in the female screw cannot be removed so much unless a tightening pressure is applied to the notch-shaped portion (31). Before the axial force is applied, there is a clearance in the threaded portion, so that the axial force is applied after passing through the notched part (31), the friction coefficient changes due to the thick coating film, etc., and tightening is performed with tightening torque management. In some cases, normal axial force may not be present.
[0004]
[Means for Solving the Problems]
In the present invention, as means for solving the above-described conventional problems, the screw (2) tip of the bolt (1) is located at ± 15 ° to 80 ° on the shaft end side with respect to the axis (AX) of the bolt screw. A plurality of notch-shaped portions (3) and (31) are provided at an angle (α) (θ) of °, and the inner flank angle (33) of the inlet notch-shaped portion (3) of the bolt (1) is the outer flank angle. (34) has a steeper slope, and the notch shape portion (31) thereafter has a steeper outer flank angle (34) than an inner flank angle (33). The remaining notch-shaped portions (31) also have flank angles that are staggered. Further, the bolt (1) is formed by rolling with the production die of FIG.
This invention is a volt | bolt which consists of the above structure.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
A bolt according to an embodiment of the invention is shown in FIG. The bolt shown in FIG. 1 has an angle (α) (θ) of ± 15 ° to 80 ° on the shaft end side with respect to the axis (AX) of the bolt screw portion at the tip of the screw portion (2) of the bolt (1). ), A plurality of notch-shaped portions (3) and (31) are provided, and the inner flank angle (33) of the inlet notch-shaped portion (3) of the bolt (1) is steeper than the outer flank angle (34). In the notch shape portion (31) thereafter, the outer flank angle (34) is steeper than the inner flank angle (33). The remaining notch-shaped portions (31) also have flank angles that are staggered. The steep flank angle is 66 ° to less than 70 ° , and preferably β = 68 ° . Further, the bolt (1) is formed by rolling with the production die of FIG. The forming process of the notch shape forming part (3) (31) and the notch shape forming part inner and outer flank angles (33) (34) of the front end of the bolt screw of the manufacturing die is performed by an electric discharge process or a press process. To form. The bolt (1) manufactured in this way removes deposits such as paint thick film and spatter by removing the outside of the screw thread of the nut at the notch shape portion (3) of the inlet, and then the notch shape. The upper part (31) scrapes and removes the inner side of the thread, but due to the difference between the inner and outer flank angles (33) and (34), it can be further removed because it is rubbed by the notched part from the conventional product (Fig. 4). Since it discharges | emits from a notch shape part (31), seizing is prevented more effectively without clogging.
[0006]
The present invention is not limited to the embodiment shown in the drawings, and various modifications can be made without departing from the scope of the present invention. For example, in the present invention, the bolt head shape may be a hexagonal shape or a round shape, or may not have a collar or a flange on the lower side of the head neck, and a guide boss or the like is provided at the tip. However, it may be attached or may have a surface at the tip or not. Not only a normal nut but a female screw hole provided in a part may be used. The production die may be a flat die or a rotary die. Further, the forming process of the manufacturing die only needs to be formed not only by the electric discharge process and the press process but also by the cutting process.
[0007]
【The invention's effect】
According to the bolt of the present invention, the coating thick film uniformly adhered in the female screw could not be removed much unless the tightening pressure is applied to the notch shape portion, but by changing the inner and outer flank angles of the notch shape plural portions. Therefore, even if there is no tightening pressure, the coating thick film uniformly adhered in the female screw is further removed, and seizure due to the coating thick film can be effectively prevented.
[Brief description of the drawings]
1 to 8 show an embodiment of the present invention.
1 is a front view of a bolt according to the present invention. FIG. 2 is a right side view of a bolt according to the present invention. FIG. 3 is an enlarged front view of a portion of a bolt according to the present invention. AX-AX sectional view of the bolt front end portion enlarged front view of the present invention [Fig. 6] Manufacturing die front view [Fig. 7] B portion detail cutout shape enlarged front view [Fig. 8] AA sectional view in FIG. Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 This invention bolt 2 Thread part 3 Entrance notch shape part 31 Notch shape part 33 after entrance notch shape part Notch shape flank inner part 34 Notch shape flank outer part AX Bolt screw part axis | shaft (alpha) Entrance notch shape Part angle θ Notch shape part angle β after notch shape part Notch shape flank steep part angle γ Screw part flank angle 10 Manufacturing die B Notch part bolt 1 Pitch range detail part 7 Bolt screw valley forming part 8 Bolt thread formation part

Claims (3)

A plurality of notch shapes are provided at the tip of the bolt screw part, and one flank angle of the thread notch of the bolt screw part notch shape part provided with a plurality of the notch shapes is steeper than the other flank angle. cage, besides the inner flank angle notch shape is provided with a plurality and outer flank angles become alternately successively more steep and the inner outer inner ... a plurality of notches shaped portion from the inlet notch-shaped portion Bolt characterized by being. The steep flank angle is in a range of 66 ° or more and less than 70 °, where the other flank angle of the screw thread of the bolt screw portion notch shape portion is 60 °. The described bolt. A plurality of notch shapes are provided at the tip of the bolt screw portion, and one flank angle of the thread notch shape portion provided with a plurality of the notch shapes is steeper than the other flank angle. In addition, the inner flank angle and the outer flank angle in which a plurality of the notch shapes are provided are alternately steeply changed from the inlet notch shape portion to the notch shape portion on the inner outer side inner side, and so on. manufacturing die for manufacturing a bolt according to claim 1, characterized in that it it.

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