JP2006292717A5 - - Google Patents

Description

Bolt and manufacturing method

  The present invention relates to an axial force measurement bolt using ultrasonic waves or the like.

Conventionally, as the axial force measuring bolt, it is common to measure the axial force and axial force measuring instrument flat portion formed in the bolt head with a bolt shaft end to form the flat portion of the ultrasonic wave or the like is there.

However, whether to use axial force measuring instrument such as ultrasonic waves formed by switching cutting and polishing the both ends planar portion, although either forming both end flat portion in cold heading, machining and polishing It is costly, and because tension diagonal hexagonal shape of the bolt head periphery is deteriorated in forming the flat portion with two-stage process for cold heading, machining the flat portion in a more multi-step or, Although it is possible to form a flat part with a concave shape on the head and make it diagonal, the multi-step process is expensive, and the shape of the concave part is limited to the size of the sensor part such as ultrasonic waves entering the concave part Will be. Also, when an axial force is applied, an error may occur in the axial force measurement due to the warp on the flat portion of the head, and a C surface portion is formed at the end of the bolt shaft in consideration of the insertion of the bolt. In the case of intermediate forging, the flat portion and the C-plane portion cannot be formed unless a multistage process is used. Or it became a cutting process etc., and the axial force measuring bolt had a problem that the cost was still high.

  Accordingly, an object of the present invention is to invent a bolt head and end shape and manufacturing method at low cost and to provide an inexpensive axial force measuring bolt.

In the present invention, as a means for solving the above-described conventional problems, the outer periphery of the bolt head is a polygonal shape, and a contour polygonal concave portion in which the apex position is aligned with the head outer periphery polygonal shape is formed on the upper surface of the bolt head. formed, the polygonal shape is formed in a range of hexagonal 12 triangular shape, the upper surface on the inside of the recess of the contour polygon formed on the head top surface is a plane section of polygonal or circular shape A certain platform is formed. The height of the planar portion of the base portion which is formed on the inside of the recess of the bolt head top surface is the same or young interference high position the outer portion from the concave portion, the concave portion inside the base portion of the bolt head top surface head diameter of the flat portion ranges from 1/5 to 4/5 of 2 width across flats of the outer polygonal shape of the bolt head, the recess bottom surface of the head, over the recess rim and the said base portion outer edge Inclined in the range of −30 ° to + 30 ° with respect to the upper surface of the part, and the depth of the contour polygonal concave portion is formed within ½ of the head height. The heads of these bolts are processed in a cold forging machine in two to four steps, and at the same time, the shaft and the cut flat portion of the bolt tip are formed. The cut plane part has a parallelism with the head plane part of 0.1 mm or less and an average roughness Rz of 12.5 or less. The front end portion of the bolt is formed by rolling from a vertical plane, and at the same time as the threading of the shaft portion, the flat surface portion is left inside the front end, and the C surface portion is formed while extending the outside. The bolt of the present invention is formed by cold forging 2 to 4 step process and rolling process to produce an inexpensive axial force measuring bolt.

The bolt capable of measuring axial force with ultrasonic waves or the like of the present invention is a contour polygon shape in which the apex position of the head outer periphery polygon shape is aligned with the upper surface of the head of the outer periphery polygon shape of the bolt in a two-step process using a cold forging machine. recess and thereby stretched sufficiently diagonal of the head of the outer peripheral polygonal by the upper surface inside thereof to form a base portion a flat surface portion, the planar portion is contoured polygonal recess inside the base portion upper surface, a bolt since slightly higher or outer portion and the same height than the recess of the upper surface, can be measured regardless of the size of the sensor such as ultrasound, also the outer circumference of the head top surface when the bolt of the present invention is that the axial force is applied by absorbing warping in the concave portion of polygonal, since it is prevented from being affected in the warp in the plane of the base part, thereby enabling the axial force measurement in ultrasonic wave or the like. Further to form a cut plane of the bolt shank destination end simultaneously in two step process, with rolling and the bolt shaft portion and a distal portion, while leaving most of the plane portion at the same time the distal end within the side while threading If the C-plane part is formed, the area of the flat part inside the tip can be made larger than that of the conventional C-face machining, so that the axial force measurement with ultrasonic waves becomes more accurate than the conventional C-face machining, and the bolt shaft part. since the planar portion of the tip portion is formed on the inner side, rather difficulty scratches etc. dent, the influence of reflection noise due dents or the like during measurement ultrasonic axial force is reduced. The bolt of the present invention can be manufactured as a normal bolt because the cost is not much different from that of a normal bolt, and can be used as a normal bolt. In that case, the axial force measurement for inspection or the like can be performed at any time. Also, if an ultrasonic axial force control tightening machine is used, stable axial force tightening is possible.

Embodiments of the present invention will be described below.
A bolt according to an embodiment of the invention is shown in FIG. The outer periphery of the bolt head shown in FIG. 1 has a hexagonal shape (5), and a concave portion having a hexagonal outline in which the apex position is aligned with the outer periphery hexagonal shape of the bolt head on the upper surface of the bolt head. (3) is formed in the upper surface side, the recess (3) the bottom surface of the contour hexagonal shape is inclined at an angle within + 30 ° from -30 ° (Xa) with respect to the head portion upper surface (Xb). The hexagonal groove depth (Ya, Yb, Yc) should be within ½ of the head height. The bolt top is to the inside of the upper surface in the side of the contour hexagonal recess (3) is formed base part is polygonal or circular flat portion (6) (6A) is 該台portion (6A) The diameter of the flat portion (6) is in the range of 1/5 to 4/5 of the two-sided width of the hexagonal shape of the outer periphery of the bolt head . The height equal to or above base portion of the flat portion (6) of the bolt recess (3) than the outer portion of the upper surface (1A) and the recess (3) of the contour hexagonal inner base portion (6 A) (6A ) Is a slightly high position. The manufacturing method of the said bolt is processed in a cold forging machine by a 2-4 step process, and simultaneously forms the cut plane part (4a) of a bolt shaft part (2) front-end | tip part. The cut plane part has a parallelism with the head plane part of 0.1 mm or less and an average roughness Rz of 12.5 or less. Leaving then rolling maximally flat portion in the bolt shank distal the side while at the same time the screw processed (4b) of the shaft portion in the processing (2) and the shaft portion perpendicular cut plane (4a) of the tip (2) , it forms a C surface (7) while extending the shaft portion outer periphery.

A periphery of the bolt head as shown in FIG. 1 is hexagonal shape (5), in the upper surface of the bolt head, the recess of the contour hexagonal shape matching the vertex positioned on the outer peripheral hexagonal shape of the bolt head ( 3) forms the shape of, preferably a slight R shape for the die life is at each corner. Inner bottom surface angle is preferably + 1 ° ~ + 2 ° inclined within respect the head portion upper surface + 30 ° from -30 ° (with respect to the line L) (Xa) (Xb) of the recess (3) of the contour hexagonal If the outer side is made deeper and the outer side is made shallower, the reflection noise at the time of ultrasonic axial force measurement is reduced, and the diagonal tension (8) of the outer periphery of the bolt head is improved. The depth (Yb) of the contour hexagonal recess (3) is within 1/2 of the head height, preferably about 1/8. The inside of the bolt top in side contour hexagonal recess (3), the upper surface preferably of a polygonal shape or a circular shape are base portion having a circular flat portion (6) (6A) is formed, The diameter of the plane portion (6) is in the range of 1/5 to 4/5 of the width of the two faces of the outer periphery hexagonal bolt head , preferably about 1/2. The height of the portion (1A) outside the concave portion (3) on the upper surface of the bolt and the flat portion (6) of the base portion (6A) inside the contour hexagonal concave portion (3) is the same or desirably the above-mentioned base portion ( The flat portion (6 ) of 6A) is set to a slightly higher position. In the cold forging machine, the bolt is preferably processed in a two-stage process, and at the same time, a shaft plane and a cut plane portion (4a) at the tip are formed. The cut plane part has a parallelism with the head plane part of 0.1 mm or less and an average roughness Rz of 12.5 or less. After that, by rolling the shaft part (2) and the cut plane (4a) perpendicular to the axis of the tip part of the shaft part (2), the flat part (4b) ) leaving most of, because C surface while extending the outer periphery (7) is formed area made large as compared with the distal planar portion of the conventional C-plane processing (44) (444), the ultrasound or the like Axial force measurement is accurate.

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, the head if an embodiment has been illustrated the head periphery hexagonal bolts in the form, the head outer circumferential polygonal and the inner side recess contour polygonal same vertex portion located in the range of hexagonal 12 corners of the invention The outer peripheral polygonal bolt may be used. It may be slight R shape for the die life at each corner of the reentrant polygonal shape of the inner side. Since the bottom surface angle of the recess is to reduce malfunction of the reflected wave of the ultrasonic wave, it may be changed to the optimum angle depending on the bolt shape (length, diameter, etc.) in the range of −30 ° to + 30 °. Also, the head neck side may or may not have a collar or flange, and a washer may or may not be incorporated. Bolt flat portion of the inner base portion of the hexagonal recess of the upper surface in the side is the polygonal recess outside circumference, inner or base portion (6A) periphery may be a circular shape a polygonal shape. The bolt shaft end face portion of the bolt head of the present invention may be flat or may be provided with a C-face portion that leaves the maximum flat portion inside the tip by rolling. If with a C face leaving maximize flat portion on the tip in side rolling of the present invention the bolt shank end face, the area is made large as compared with the distal planar portion of the conventional C-plane processing, ultrasonic Since the axial force measurement using sound waves or the like becomes accurate, the bolt head may be a conventional polished bolt or a flat portion of a conventional recess cold work.

1 to 6 show an embodiment of the present invention.
Front view of the bolt of the present invention Top view of the bolt of the present invention AA sectional view in FIG. Front view of conventional grinding bolt Front view of conventional recessed bolt Top view of conventional recessed bolt A-A cross-sectional view within -30 ° contour polygonal recess bottom against the head portion upper face of the present invention the bolt in FIG. 2 A-A sectional view of a contour polygonal recess bottom surface of the present invention the bolt is within + 30 ° with respect to the head portion upper surface in FIG. 2 Sectional view of the inner flat surface portion and C surface portion in the rolling process of the head flat shape of the conventional polishing bolt or the like and the tip of the present invention Sectional view of the inner flat surface portion and the C surface portion in the rolling process of the head flat shape of the conventional recessed bolt and the present invention tip Sectional view of the flat part and C-plane part of a conventional grinding bolt Sectional view of the inner flat surface and C surface of the conventional recessed bolt Sectional view of the planar portion and the C surface of the base portion of the recess side of the present invention the bolt Rolling process front side view of the bolt of the present invention Rolling side view of the bolt of the present invention

Explanation of symbols

1 the invention the bolt head 2 threaded portion 3 contour hexagonal recess 4a distal rolling contour hexagonal recess of the front planar portion 4b rolling end surface plane 5 bolt head periphery hexagonal 6 head upper surface of the Flat portion 7 on the inner base portion Tip rolling processing C surface portion 8 Head outer periphery hexagonal shape diagonal tension portion 11 Conventional polishing bolt head portion 22 Screw portion 44 Polishing end surface flat portion 55 Hexagonal trim shape outer portion 66 Head portion Polishing flat portion 111 Cold forging head portion of conventional concave bolt 222 Screw portion 444 Cold forging end surface flat portion 555 Hexagonal recess shape outer 666 Hexagonal recess shape inside flat portion Xa Angle of polygonal recess bottom surface (on shaft portion) (On the top side of the head within -30 °)
Xb Reverse angle of the bottom of the polygonal recess (within + 30 ° on the top side of the head relative to the shaft)
9a threaded portion C face simultaneous rolling die stationary 9b thread portion C face simultaneous rolling die movable Yc hexagonal groove depth Ya Xa side hexagonal recess maximum depth Yb Xb side hexagonal recess Depth

Claims (10)

Bolt that can measure axial force with ultrasonic waves, etc. The outer periphery of the bolt head has a polygonal shape, and a concavity with a contoured polygon shape is formed on the upper surface of the bolt head with the apex position aligned with the outer periphery polygonal shape of the head Bolt characterized by that. The bolt according to claim 1, wherein the polygonal shape of the outer periphery of the head and the contour of the concave portion is formed in a range of hexagonal shape to dodecagonal shape . The bolt bolt upper surface on the inside of the recess of the contour polygon formed on the head top surface according to claim 1 or 2, base portion is a flat portion of the polygonal or circular shape is formed. The height of the planar portion of the base portion which is formed inside the recess of the bolt head upper surface, to any one of claims 1 to 3 is the same or young interference high position the outer portion from the recess The described bolt. The bolt diameter of the flat portion of the concave inner base portion of the head top surface, any one of claims 1 to 4 is in the range of 1/5 of 4/5 of 2 width across flats of the outer polygonal shape of the bolt head The bolt described in the item . Concave bottom surface of the bolt head, in any one of claims 1 to 5 over the recess rim and the said base outer edge is inclined in a range of + 30 ° from -30 ° with respect to the head top surface The described bolt. The bolt according to any one of claims 1 to 6 , wherein a depth of the concave portion of the contour polygonal shape of the bolt is within ½ of a head height. The manufacturing method of the bolt as described in any one of Claims 1-7 which processes the said bolt in a 2-4 step process in a cold forging machine. A manufacturing method of a bolt according to any one of claims 1 to 7, the threaded shaft portion is subjected to rolling to a bolt shank having a vertical planar portion in the axial to the tip at the same time leaving a flat portion at the distal end inside method for producing a bolt, characterized in that to form a C face while extending the shaft portion outer circumferential performed.   The bolt manufacturing method according to claim 9, wherein the shaft portion and the tip portion of the bolt are formed by simultaneous rolling.