JPH08145025A - Bolt fastening structure - Google Patents

Abstract

PURPOSE: To provide a bolt fastening structure with which a bolt can be easily fastened. CONSTITUTION: A mounting bracket 10 adapted to be fixed to a frame bracket is provided under an insertion hole 8 formed in the floor 4 of a cabin. A circular plate 11 having upright rotation checking pawls 12 is welded to the mounting bracket 10. A bolt 9 is through the insertion hole 8 which is then closed by a cap 7. The cap 7 is formed in the peripheral surface of its engaging part 22 with an inclined surface 21 having an inclined angle β which is smaller than the inclined angle a of an inclined part 9c of the head part 9a of the bolt 9, the inner diameter A of the opening edge 1 of the engaging part 22 is set to be smaller than the outer diameter B of the head part 9a. When the head part 9a abuts against the inclined surface 21, the distance D between this abutting position C and the front ends of the rotation checking pawls becomes smaller than the distance E between the abutting position C and the head part 9a. Accordingly, the inclined surface 21 effects a component force FS of an abutting force FU produced upon the abutting, in an external direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an easy tightening operation for fixing a lower member, which is separated from and covered by an upper member, to an object by a bolt inserted through an insertion opening provided in the upper member. The present invention relates to a bolt fastening structure that can be performed.

[0002]

2. Description of the Related Art A structure shown in FIG. 4 is known as a structure for fixing a vehicle body such as a driver's cab to a chassis frame (D-5 of Nissan Motor Co., Ltd. Service Peripheral Report No. 590).
See page).

According to this prior art, a mount bracket 52 provided on the lower surface of a floor 51 of a vehicle body and a frame bracket 53 attached to a chassis frame are fastened with rubber bushes 58, 58 by bolts 54 and nuts 59. ing. At the time of fixing, the bolt 54 is inserted through the bolt insertion port 55 formed in the floor 51 and fastened with the nut 59. At this time, in order to prevent idling of the bolt 54, a tool such as a wrench is inserted from the insertion hole 55 of the floor 51 to prevent idling, the bolt 54 is set on the head 54a, and the nut 59 is fastened downward. And nut 59
After fastening, the cap 55 is put on the insertion hole 55 of the floor 51, and a floor mat is laid on the upper surface thereof.

[0004]

Since a tool such as a wrench is inserted from the insertion hole 55 to prevent the bolt 54 from rotating and the nut 59 is tightened while supporting the head 54a of the bolt, the workability is poor and the nut is fastened. There is a problem in that the work process is restricted because the rear cap 60 is covered on the insertion port 55 and the floor mat is laid.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a bolt fastening structure which facilitates the bolt fastening operation.

[0006]

In order to solve the above problems, according to the present invention, a lower member spaced apart from an upper member is inserted through an insertion opening provided in the upper member. When fixing to an object with a bolt, the head of the bolt is housed between the upper member and the lower member, and the insertion port is provided with a cap capable of closing the insertion port, In a bolt fastening structure in which the lower member and the object are fastened by the bolt and the nut, a bolt detent portion that abuts the head of the bolt on the upper surface of the lower member and suppresses rotation of the bolt. The engaging groove is provided on the outer peripheral portion of the cap and is engaged with the edge portion of the insertion opening, and an engaging portion bulging downward is formed at a lower portion of the engaging groove. Inside of the part, the bolt moves upward And when the bolt rotation stopper by contact the to the extent that rotation of the bolt is suppressed head abuts the inclined surface to cause a component force of the contact force due to the abutment in the outer direction is formed.

[0007]

In the above structure, when the lower member is fixed to the object with the bolt, first, the bolt is inserted through the insertion opening opened in the upper member, and then the cap is fitted into the insertion opening and closed. At this time, the locking groove is locked to the edge portion of the insertion opening to prevent the cap from coming off, and at the same time, the inner surface of the engaging portion abuts on the head of the bolt to prevent rotation by rotation stop. The upper movement of the bolt is restricted within the range where

Then, a nut is attached to the tip of the bolt, and the nut is screwed in. At this time, a force may be applied to the bolt in the direction in which the nut is screwed in, that is, upward, so that the bolt may move upward. When the bolt moves upward, the head portion contacts the inclined surface formed on the inner surface of the engaging portion, and the component force of this abutting force acts outward in the engaging portion. By this component force, the engaging portion is expanded outward, and the locking force between the locking groove and the insertion opening is increased, so that the cap is prevented from coming off. Further, the head portion of the bolt engages with the bolt stopper to prevent the bolt from idling, and the bolt and nut are fastened.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a fixing portion provided with a bolt fastening structure of the present invention, showing a state in which a cabin 1 of a truck is fixed to a frame bracket 3 (object) provided on a frame 2. .

The cabin 1 is composed of a floor 4 (upper member) forming a floor surface and a side panel 5 forming a peripheral wall connected to the floor 4, and a recess 6 is provided in the floor 4. There is. An insertion port 8 closed by a cap 7 is provided in the center of the recess 6, and the insertion port 8 has a size such that a bolt 9 can be inserted therein.
Further, on the bottom surface side of the floor 4, a side panel 5 on one end side and a mounting bracket 10 (lower member) welded to the floor 4 after the other end side is bent are provided at predetermined intervals. The head 9 a of the bolt 9 is housed between the mounting bracket 10 and the mounting bracket 10. As shown in FIGS. 2 and 3, the head portion 9a has a shape in which the side surface of the truncated cone is vertically cut at the bottom surface side, and has an inclined portion 9c and vertical walls 9d and 9d.

The mounting bracket 10 includes:
A mounting hole 10a is formed at a position corresponding to the insertion port 8, and a threaded portion 9b of a bolt 9 penetrates the mounting hole 10a. This bolt 9
By the detents 12 and 12 of the circular plate 11 welded to the mounting bracket 10, the vertical wall 9d,
The rotation is restricted at 9d.

The threaded portion 9b penetrating the mounting hole 10a has a collar 13 and a collar 13
After passing through the frame hole 3a of the frame bracket 3 via the first rubber bush 14 which is fitted to the outside, the nut 17 is tightened via the second rubber bush 15 and the washer 16.

On the other hand, the cap 7 for closing the insertion port 8
As shown in FIG. 3, while fitting in the insertion opening 8,
It has a locking groove 20 that is locked to the edge portion 8a of the insertion port 8 in a state of being fitted inside, and the lower portion of this locking groove 20 is provided with the inclined portion 9c formed on the head portion 9a. Engaging portion 22 to be engaged
Are formed. The engaging portion 22 has an inclined surface 21 having an inclination angle β that is gentler than the inclination angle α of the inclination portion 9c.
have. Further, the inner diameter dimension A at the opening edge portion of the engaging portion 22 is set to be smaller than the outer dimension dimension B of the head portion 9a (A <B), and when the head portion 9a moves upward, the inner peripheral edge is the head portion. It is formed so as to come into contact with the portion 9a. The distance D from the contact position C to the tips of the detents 12 and 12 is set to be smaller than the distance E from the contact position C to the base end of the head 9a (D).
<E). That is, the inclined surface 21 contacts within the range in which the head portion 9a of the upwardly moving bolt 9 is restricted by the rotation stoppers 12 and 12, and the component force FS of the contact force FU accompanying this contact. Are formed so as to be generated in the outward direction.

In this embodiment having the above structure, when fixing the cabin 1 to the frame bracket 3 provided on the frame 2, first, the first rubber bush 14 is firstly attached.
The collar 13 which is fitted to the frame is attached to the frame hole 3a of the frame bracket 3. Subsequently, the collar 13 is attached to the mounting hole 10a of the mounting bracket 10.
And bolt 9 from the insertion hole 8 on the floor 4.
Insert. Then, after the cap 7 is fitted in the insertion opening 8 and closed, the second rubber bush 15 is fitted to the tip end portion of the collar 13. Next, the screw part 9 of the bolt 9
The nut 17 is screwed into b through the washer 16.

At this time, as shown in FIG. 3, even if the bolt 9 may be moved upward by applying a force in the direction in which the nut 17 is screwed into the bolt 9, that is, in the upward direction, the head portion 9a may be replaced by the cap 9a. When the bolt 9 comes into contact with the engaging portion 22, the upward movement of the bolt 9 is restricted within a range where it does not separate from the detent 12. Further, since the component force FS of the contact force FU at this time acts outward by the inclined surface 21, the engaging portion 2
2 is pushed outwards. Therefore, the locking groove 20
The locking force between the edge portion 8a of the insertion opening 8 and the
Is prevented from coming off. Therefore, the bolt 9 is
Since a does not separate from the detents 12 and 12 and idles, the bolt 9 can be easily tightened.

Although the bolt 9 in this embodiment has the head 9a provided with the inclined portion 9c, for example, in the case of a bolt having a hexagonal column head, the corner of the head is The part may be in contact with the inclined surface 21 of the engaging part 22.

[0017]

As described above, according to the present invention, the bolt inserted through the insertion opening is restricted from moving upward by the cap closing the insertion opening, and further, when the bolt moves upward. Even if there is, the cap is prevented from coming off by increasing the locking force between the locking groove and the insertion opening. Therefore, the head of the bolt does not separate from the detent and does not rotate idly, and the bolt tightening operation becomes easy. Furthermore, since the fastening work can be performed even after the bolt insertion opening is covered with the cap and the floor mat is spread, the working process is not restricted.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view showing a rotation stopping plate of the embodiment.

FIG. 3 is an enlarged view of a main part of FIG. 1;

FIG. 4 is a half sectional view showing a conventional example.

[Explanation of symbols]

 3 Frame Bracket (Target) 4 Floor (Upper Member) 7 Cap 8 Insertion Port 8a Edge 9 Bolt 9a Head 10 Mounting Bracket (Lower Member) 12 Detent 20 Locking Groove 21 Inclined Surface 22 Engagement FU Contact Force FS component force

Claims (1)

[Claims] 1. When fixing a lower member spaced apart from an upper member to an object by a bolt inserted through an insertion opening provided in the upper member, the head of the bolt is
A cap that is housed between the upper member and the lower member and that can close the insertion port is provided in the insertion port, and the lower member and the object are fastened with the bolt and the nut. In the fastening structure of a bolt, a bolt rotation preventing portion is provided on the upper surface of the lower member, which is in contact with the head portion of the bolt to suppress rotation of the bolt, and an edge portion of the insertion opening is provided on an outer peripheral portion of the cap. Is formed with a locking groove, and an engaging portion that bulges downward is formed in the lower portion of the locking groove. When the bolt moves upward inside the engaging portion, The bolt is characterized in that the head portion abuts within a range in which the rotation of the bolt is suppressed by the rotation preventing portion, and an inclined surface is formed which causes a component of the abutting force resulting from the abutment to the outside. Fastening structure.