JP2006189077A - Member fastening structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide compact member fastening structure capable of uniforming the bearing surface pressure. <P>SOLUTION: A distance R between a thread 9, to which a bolt 4 is screwed first, and a bearing surface 10 of a fastened member 1 is structured to be uniform in a shaft surface of a nut 5. Distribution of the pressure to be applied to the bearing surface 10 is thereby uniformed, and sink-down of the bearing surface 10 due to concentration of the bearing surface pressure is prevented to restrict looseness of the nut 5. Since a contact area between the nut 5 and the bearing surface 10 is utilized at the maximum to efficiently distribute the bearing surface pressure by uniforming distribution of the pressure to be applied to the bearing surface 10, a space can be reduced to the minimum, and height dimension can be restricted low, and compact fastening structure is realized. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fastening structure, and more particularly to a fastening structure of a member configured to include a nut.

  In general, when a member made of a non-ferrous material such as an aluminum alloy is fastened by tightening a nut, the pressure applied to a nut seating surface (hereinafter simply referred to as a seating surface) of the member (hereinafter referred to as a seating surface pressure). ) Should be less than the allowable pressure to prevent the nut from loosening due to the sag of the member. Therefore, it has been conventionally performed to extend the flange diameter of the flanged nut to increase the contact area between the member and the nut and to reduce the seating surface pressure. However, when the flange diameter of the flanged nut is extended, the seat surface pressure increases as the distance from the nut axis decreases, so the pressure distribution acting on the member seat surface becomes uneven. Become. Therefore, when a flanged nut is used, it is difficult to efficiently disperse the seating surface pressure, and in order to make the maximum seating surface pressure less than the allowable pressure, it is necessary to make the flange diameter larger.

  For this reason, when a nut with a flange is used, the flange is enlarged, the fastening structure is increased in size and weight, and the seating space according to the flange diameter is required, so that the degree of freedom in design is remarkably increased. Reduced. Further, even when the contact area between the member and the nut is increased, the seating surface pressure may still be concentrated and partially exceed the allowable pressure. Therefore, a so-called skirt nut is known in which the flange thickness of the flanged nut is increased and a hole having a diameter larger than the outer diameter of the bolt is formed inside the flange. In the skirt nut, since the difference in the distance between the thread surface (hereinafter referred to as the first thread thread) to which the bolt is first screwed in the axial plane of the nut and the seat surface becomes small, the seat surface pressure is reduced. It acts on the seat surface almost uniformly. However, in the skirt nut, in order to further reduce the difference in the distance between the first screw thread and the seating surface, it is necessary to provide a sufficient distance between the first screw thread and the seating surface.

Therefore, the use of the skirt nut is limited because the height and weight of the fastening structure are increased. Therefore, there is a conventional member fastening structure in which the contact surface of the nut is formed by the outer spherical surface and the seat surface of the member is formed by the inner spherical surface aligned with the contact surface of the nut (see, for example, Patent Document 1). . However, in this fastening structure, the distance difference between the first thread of the nut and the seat surface is smaller than when using a flanged nut, but the center of the outer spherical surface of the nut (the center of the sphere) Since it is on the axis of the nut, there is still a difference in the distance between the first thread of the nut and the seating surface, and the seating surface pressure may concentrate and partially exceed the allowable pressure.
Japanese Patent Laid-Open No. 9-11701 (paragraph numbers 0018 to 0022, FIG. 1)

  Then, this invention was made | formed in view of the said situation, and it aims at providing the fastening structure of the member in which a seat surface pressure is equalized while being compactly formed.

In order to achieve the above object, the invention described in claim 1 of the present invention is a fastening structure of a member in which a recessed seat surface aligned with a contact surface of a nut is formed on a fastened member, In the axial plane of the nut, the distance between the thread surface of the nut to which the bolt is first screwed and the seat surface is uniform.
According to a second aspect of the present invention, in the member fastening structure according to the first aspect, the nut has a contact surface formed by a curved surface having a uniform distance from a screw thread to which the bolt is first screwed in the axial plane. It is characterized by being.
According to a third aspect of the present invention, in the member fastening structure according to the second aspect, the nut has a contact surface approximating a curved surface having a uniform distance from a screw thread to which a bolt is first screwed in an axial plane. It is characterized by being formed by an outer conical surface.

  In order to achieve the above object, the invention according to claim 4 of the present invention is a fastening structure of a member in which a concave seating surface aligned with a contact surface of a nut is formed on a fastened member, The contact surface of the nut is provided on a washer attached to the nut, and the distance between the thread surface of the nut and the seat surface on which the bolt is first screwed in the axial plane of the nut is configured to be uniform. Features.

Accordingly, in the first and fourth aspects of the present invention, the distance between the thread on which the bolt is first screwed and the seating surface of the member to be fastened becomes uniform in the axial plane of the nut.
In the invention according to the second aspect, the distance between the thread on which the bolt is first screwed on the axial plane of the nut and the seat surface formed by the curved surface of the member to be fastened becomes uniform.
In the invention according to the third aspect, the distance between the thread on which the bolt is first screwed in the axial plane of the nut and the seat surface formed by the outer conical surface of the fastened member is substantially uniform.

  It is possible to provide a fastening structure for a member that is compact and has a uniform bearing surface pressure.

  An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the fastening structure of this member is such that a bolt 4 is inserted into a bolt insertion hole 3 penetrating the overlapped members 1 and 2 and the nut 5 screwed into the bolt 4 is inserted. The fastened members 1 and 2 are fastened by fastening. As shown in FIG. 2, the nut 5 has a contact portion 6 that comes into contact with the fastened member 1 on one side (the lower side in the paper view in FIG. 2) in the axial direction (the vertical direction in the paper view in FIG. 2). A counterbore 7 having a predetermined depth and having an inner diameter dimension through which the bolt 4 can be inserted is formed on the top of the contact portion 6 on the same axis as the nut 5. Further, the nut 5 has a contact surface 8 of the contact portion 6 and a thread 9 (the screw to be screwed to the nut 5 is a single thread) to which the bolt 4 is first screwed on the axial plane of the nut 5. Since it is a screw, when the screw of the nut 5 is developed on a plane, there is one screw thread 9, but for convenience, the screw thread 9 on which the bolt 4 is first screwed on the axial plane of the nut 5 will be described below. It is formed to include a curved surface obtained by rotating a circle C having a radius R centering on the center O) around the axis of the nut 5.

  As shown in FIG. 1, the fastened member 1 is formed with a concave seating surface 10 having a curved surface aligned with the contact surface 8 of the contact portion 6 of the nut 5. As described above, in the fastening structure of this member, the contact surface 8 of the contact portion 6 of the nut 5 is a circle C having a radius R centered on the first thread 9 on the axial plane of the nut 5. The center O of the circle C is a surface 9a on the pressure receiving side (upper side in the drawing in FIG. 2) of the first thread 9. The distance from the axis of the upper nut 5 is set to a position equal to the pitch circle radius of the nut 5 screw. The angle plane of the axial plane of the nut 5 is set around the axis of the nut 5 such that the first thread 9 is the start of a single thread. The fastened member 1 is made of an aluminum alloy, and the fastened member 2 is made of steel.

  Next, the effect | action of the fastening structure of this member is demonstrated. First, the bolt 4 is inserted into the bolt insertion hole 3 of the fastened members 1 and 2 from the fastened member 2 side (the lower side in the drawing in FIG. 1). Next, the nut 5 is screwed into the bolt 4 through which the fastened members 1 and 2 are penetrated, and the contact surface 8 of the contact portion 6 of the nut 5 contacts (fits) the seat surface 10 of the fastened member 1. Is done. Then, when the nut 5 screwed to the bolt 4 is tightened with a predetermined tightening torque, an axial force is generated in the bolt 4 and the fastened members 1 and 2 are fastened by the axial force. In this state, on the axial plane of the nut 5, the first thread 9 of the nut 5 (the point of action between the bolt 4 and the nut 5. In this embodiment, the center O of the circle C in FIG. 2). Since the distance R between the seating surface 10 and the seating surface 10 is uniform, the surface pressure distribution on the seating surface 10 is made uniform. In the fastening structure of the member, the distance R between the thread 9 to which the bolt 4 is first screwed and the seat surface 10 is uniform in all axial planes around the axis of the nut 5. The surface pressure distribution on the surface 10 is made uniform.

This embodiment has the following effects.
In the fastening structure of this member, the distance R between the thread 9 to which the bolt 4 is first screwed in the axial plane of the nut 5 and the seating surface 10 of the fastened member 1 is configured to be uniform. The pressure distribution acting on the surface 10 is made uniform. Therefore, the seat surface 10 is prevented from sag due to concentration of the seat surface pressure, and the loosening of the nut 5 is suppressed. In addition, since the pressure distribution applied to the seating surface 10 is made uniform, the contact surface pressure can be efficiently dispersed using the contact area between the nut 5 and the seating surface 10 to the maximum, Since the minimum space is required and the height dimension is kept low, the fastening structure is compact.

In addition, embodiment is not limited above, For example, you may comprise as follows.
In the fastening structure of this member, the contact surface 8 of the nut 5 has a circle C with a radius R centering on a thread 9 to which the bolt 4 is first screwed on the axial plane of the nut 5. As shown in FIG. 3, the contact surface 8 of the nut 5 is formed by an outer conical surface approximated to the curved surface, and the seat surface 10 is made to be the contact surface. 8 may be formed so as to be aligned with each other.
Even in this case, since the distance R between the thread 9 to which the bolt 4 is first screwed in the axial plane of the nut 5 and the seating surface 10 of the member 1 to be fastened becomes substantially uniform, it acts on the seating surface 10. The pressure distribution is made substantially uniform. In addition, the manufacturing cost is reduced because the manufacturing is easy as compared with the case where the contact surface 8 is formed of a curved surface.

In the fastening structure of this member, the contact surface 8 is formed on the contact portion 6 formed on the nut 5, but as shown in FIG. 4, the shaft portion 11 is formed on the nut 5, and the shaft portion 11 is You may comprise so that the contact surface 8 may be formed in the washer 12 with which it is mounted | worn.
In this case, if necessary, the use of the washer 12 having the contact surface 8 having a different shape makes it possible to make one nut 5 correspond to the seat surface 10 having various shapes.

It is explanatory drawing of the fastening structure of this member. It is explanatory drawing of the nut used for the fastening structure of this member. It is explanatory drawing which shows other embodiment, Comprising: It is a figure which shows the nut in which a contact surface is especially formed of an outer conical surface. It is explanatory drawing which shows other embodiment, Comprising: It is a figure which shows the state by which the washer in which the contact surface was formed was especially mounted | worn with the nut.

Explanation of symbols

  1, 2 Fastened member, 5 Nut, 8 Contact surface, 9 Thread, 10 Seat surface, 12 Washer

Claims (4)

  A fastening structure of a member in which a concave seating surface aligned with a contact surface of a nut is formed on a member to be fastened, wherein the bolt thread is first screwed on the axial plane of the nut and the thread of the nut A fastening structure for a member, characterized in that the distance between the seating surface and the seat surface is uniform.   The nut fastening structure according to claim 1, wherein the contact surface is formed by a curved surface having a uniform distance from a screw thread to which the bolt is first screwed in an axial plane.   3. The nut according to claim 2, wherein the contact surface is formed by an outer conical surface approximated to the curved surface having a uniform distance from a thread on which the bolt is first screwed in an axial plane. The fastening structure of the member as described in 2. A fastening structure of a member in which a concave seating surface aligned with a contact surface of a nut is formed on a member to be fastened, wherein the contact surface of the nut is provided on a washer attached to the nut, A fastening structure for a member, characterized in that a distance between a screw thread of the nut to which a bolt is first screwed in an axial plane and a seat surface is uniform.

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