JP2000230534A - Bolt fastening structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the projection of a washer and a bolt head from the surface of a fastening part by inserting a truncated conical spacer into a truncated conical inner cylinder shaped fitting hole provided in a member to be fastened having a diameter to be reduced so that it comes close to the end opposite to the fastening base material, and threading a bolt to the fastening base material from the large diameter side end of the spacer. SOLUTION: At fastening of an inner gear and a base frame 8 to each other with bolts, a spacer 19 is inserted into a fitting hole 18 bored in a turning table, and a bolt 16 is passed through a through-hole 20 bored in the spacer 19, and in this condition, the bolt is threaded for fastening. In this case of bolt fastening, the spacer 19 is inserted in the condition in which the spacer is embedded in the fitting hole 18, and projection of a large diameter side end surface 19b of the spacer 19 from the surface of the turning table will not occur. As a result, the head of the bolt 16 is sunken in the surface of the turning table, and projected quantity of the bolt head can be reduced by the sunken quantity of the bolt head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a bolt fastening structure capable of reducing the protrusion of a bolt head.

[0002]

2. Description of the Related Art Conventionally, when an object to be fastened is to be fastened by using a bolt, conventionally, as shown in FIG.
A bolt through-hole (dumb hole) 31 is formed in the
In general, the bolt 32 is screwed into a screw hole 35 formed in the fastening portion 34 in a state where the washer 33 is applied to the surface of the portion 30 to be fastened.

[0003]

However, in the prior art, the washer 33 and the bolt head 32a protrude from the surface of the portion 30 to be fastened. In the case of a slewing bearing provided between the upper traveling structure and the movable part, as a result, it is necessary to assemble the movable part while avoiding these protruding parts. There is a problem that it must be attached, and there is a problem to be solved by the present invention.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve these problems in view of the above-mentioned circumstances, and a member to be fastened is screwed from the member to be fastened. When fastening to the fastening base material through a bolt to be fastened, a frusto-conical inner cylindrical shaped mounting hole formed in the member to be fastened so as to have a smaller diameter toward the side opposite to the fastening base material, and inserted into the mounting hole. A bolt having a truncated cone-shaped spacer and a bolt having a bolt head at the large-diameter end of the spacer and having a threaded part that passes through the mounting hole and is screwed into the fastening base material. is there. With this configuration, no washer is required, and the protrusion of the bolt head can be reduced. In this case, the spacer may be characterized in that a through hole through which the bolt screw portion penetrates is formed. Further, in the above-mentioned structure, the spacer and the bolt may be integrated.

[0005]

Next, an embodiment of the present invention will be described with reference to the drawings. In the figure, reference numeral 1 denotes a hydraulic excavator which is an example of a construction machine.
Is a crawler-type lower traveling unit 2 in which a swing unit revolving unit 3 is rotatably provided. The upper revolving unit 3 includes a cabin 4 that covers a driver's seat, an attachment working unit 5 including a bucket, an engine, and the like. As in the conventional case, it is composed of various members such as the hood 6 to be covered.

The car body 7 constituting the lower traveling body 2
A base frame 8 is integrally fixed to a central portion of the base frame 8, and an inner race 10, which constitutes a swivel bearing 9, is integrally fixed to the base frame 8 by using a bolt 16 having a fastening structure described later. On the other hand, an outer race 14 which is fitted to the inner race 10 so as to be freely rotatable and outer is integrally fixed to the swivel table 13 constituting the swing frame using bolts 16 having the same fastening structure as described above.
An output gear 15a of a turning motor 15 provided on the turning table 13 meshes with an inner gear 10a engraved on the inner periphery of the inner race 10, and is based on rotation of the output gear 15a based on forward / reverse driving of the turning motor 15. As a result, the upper swing body 3 rotates relative to the lower traveling body 2.

Now, the fastening structure of the bolt 16 will be described by taking as an example a structure for fixing the inner gear 10a and the base frame 8. On the lower base frame 8,
A screw hole 17 into which the bolt 16 is screwed is formed, while the inner diameter of the hole is formed in the upper inner gear 10a.
A mounting hole 18 is formed in the shape of an inverted frusto-conical cylindrical surface having a diameter larger than that of 7 and larger toward the upper side and inclined. Reference numeral 19 denotes a frustoconical spacer having an outer peripheral surface corresponding to the inclination of the mounting hole 18. The spacer 19 has a small diameter end face 19 a having a diameter A at the lower end of the mounting hole 18 (at the small diameter end). (The lower surface of the swivel table 13) is larger than the inner diameter B (A> B), and when the spacer 19 is inserted into the mounting hole 18 corresponding to the inclined surface, the small-diameter side end surface 19a has a through hole. 17 is set so as not to protrude from the lower end, and the diameter C of the large-diameter end face 19b is smaller than the inner diameter D of the upper end of the mounting hole 18 (the large-diameter end, the upper surface of the turntable 13) (C <D). The dimensions are set so that the large-diameter end face 19 b does not protrude from the upper surface of the through hole 17. Further, a through hole 20 which is a stupid hole for the bolt 16 is formed in the axis of the spacer 19. And the turning table 13 and the outer race 14
The bolt 16 is fastened by inserting the bolt 16 through the through hole 20 formed in the spacer 19 with the spacer 19 inserted and set in the mounting hole 18 and screwing it into the screw hole 17. ing.

In the structure described above, when the inner gear 8a and the base frame 8 are fastened by bolts, the bolts 16 are attached with the spacers 19 inserted into the mounting holes 18 formed in the swivel table 13. The bolt is screwed and fastened in a state where the through hole 20 formed in the spacer 19 is penetrated. When the bolts are fastened in this manner, the spacer 19 is inserted in a state of being embedded in the mounting hole 18 and the spacer 1 is inserted.
9 does not protrude from the surface of the turntable 13, and as a result, the head of the bolt 16 is immersed in the surface of the turntable 13.
The protrusion of the bolt head can be reduced. In addition, in this case, the inclined surface of the spacer 19 becomes wedge-shaped and the inner gear 10a is tightened. As a result, a wedge effect without slack can be exerted, reliable bolt fastening can be performed, and generation of settling on the seating surface can be avoided.

In this case, the inner gear 1
0a is sufficiently secured in FIG.
Can be configured such that the bolt head does not protrude from the surface of the swivel table 13 as in the second embodiment shown in FIG.
In this case, the bolt can be assembled without considering the protrusion of the bolt head at all, which is convenient. In addition, when the step between the inner gear 10a and the outer race 14 is not sufficiently secured, a third embodiment shown in FIG. 5 can be adopted. In other words, this is bolt 2
1, the bolt head is provided with a hexagonal hole, and the bolt head 21a is provided on the large-diameter end face 19b of the spacer 19.
In this embodiment, the large-diameter end face 19b of the spacer 19 is
It can be configured so that the bolt head 21a does not protrude from the table surface while being substantially flush with 0a.

Incidentally, the present invention is not limited to the above-described embodiment, and as shown in FIG.
Can be integrated with the bolt 22.
In this case, the bolt shown in FIG. 6 (X) has a hexagonal head and can be fastened using a normal tool such as a wrench. However, as shown in FIG. Of course. In this case, it is necessary to create a special bolt, and there is a disadvantage with respect to the first to third embodiments in which a general-purpose bolt can be adopted. it can.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a hydraulic excavator.

FIG. 2 is a schematic front view in which a part of the hydraulic excavator is cut away.

FIG. 3 is a cross-sectional view of a bolt fastening part according to the first embodiment.

FIG. 4 is a sectional view of a bolt fastening portion according to a second embodiment.

FIG. 5 is a sectional view of a bolt fastening part according to a third embodiment.

FIGS. 6 (X) and (Y) are cross-sectional views of a bolt fastening portion showing a fourth and a fifth embodiment.

FIG. 7 is a sectional view showing a conventional bolt fastening structure.

[Explanation of symbols]

 13 Swivel Table 14 Outer Race 16 Bolt 18 Mounting Hole 19 Spacer 20 Through Hole

Claims (3)

[Claims] When fastening a member to be fastened to a fastening base via a bolt screwed from the side of the member to be fastened, the member to be fastened is formed on the member to be fastened so that the diameter opposite to the fastening base becomes smaller. A frusto-conical inner cylinder-shaped mounting hole, a truncated frusto-conical spacer to be inserted and assembled into the mounting hole, a bolt head at the large-diameter end of the spacer, and a screw portion penetrating through the mounting hole is fastened. A bolt fastening structure including a bolt screwed into the base material. 2. The bolt fastening structure according to claim 1, wherein the spacer is formed with a through hole through which a bolt screw portion penetrates. 3. The bolt fastening structure according to claim 1, wherein the spacer and the bolt are integrated.