JPH08296689A - Structure of screw and its manufacture - Google Patents

Abstract

PURPOSE: To provide a structure of a screw and its manufacture which is not subjected to seizure even when an inexpensive caulking nut is used, and enables loose-prevention of the caulking nut without fail in a finally fastened state. CONSTITUTION: A male screw 67 is formed on a specified position from a leading end of a screw part 43, which screw 67 is screwed with a female screw of a caulking nut, and caulked with a loose-preventive screw part. A small diameter male screw 69 is formed from a leading end of the screw part 43 to the specified portion, which screw 69 has a diameter smaller than an outer diameter of the male screw 67, to that the loose-preventive screw can be screwed, and made of the same material as the male screw 67. Seizure of the caulking nut to the screw part 43 is prevented, while screwing can be performed to a regular position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a screw portion to which a nut member having a diameter smaller than the inner diameter of the female screw portion and having a locking screw portion formed continuously on the rear end side of the female screw portion is fastened and a screw. The manufacturing method of the part.

[0002]

2. Description of the Related Art FIGS. 6 and 7 show a strut type suspension device 1 similar to that described in Japanese Utility Model Laid-Open No. 4-63839. 6 shows a state before being assembled to the vehicle body, and FIG. 7 shows a state before being assembled to the vehicle body.

As shown in FIGS. 6 and 7, this suspension device 1 has a shock absorber 3 having one end rotatably connected to an axle and the other end supported by a vehicle body, and one side supported by the shock absorber 3. The other end has a vehicle body spring (compression coil spring) 5 supported by the vehicle body.

The shock absorber 3 is composed of a cylindrical body 7 and a piston rod 9 which is housed in the cylindrical body 7 so as to be detachable. A disc-shaped spring seat 11 is fixed to the outer periphery of the cylindrical body 7. The lower end 5 a of the vehicle body spring 5 is seated on the spring seat 11. Also,
A threaded portion 13 is formed at the tip of the piston rod 9. The threaded portion 13 penetrates the upper insulator 15 which is a vehicle body side member, and the penetrating tip has
The nut 17 is tightened. As a result, the upper end side of the shock absorber 3 is supported by the vehicle body via the upper insulator 15. Also, the piston rod 9
A bump stopper rubber 19 is attached to the intermediate portion of the.

Further, an upper spring seat 21 is arranged below the upper insulator 15. The upper spring seat 21 is in contact with the upper insulator 15 via a thrust bearing (not shown) or the like. This upper spring seat 21
The upper end 5b of the body spring 5 which is bent by a predetermined amount is seated on the seat.

When the body spring 5 is bent by the vibration from the axle, the shock absorber 3 suppresses the rebound of the body spring 5 to accelerate the damping of the vibration.
A good ride is obtained.

To assemble the suspension device 1 to the vehicle body, as shown in FIG. 6, the shock absorber 3 and the vehicle body spring 5 are set under the upper insulator 15 with the vehicle body spring 5 in a free length state, and the piston rod is set. The threaded portion 13 at the tip of 9 is passed through the upper insulator 15. Then, the nut 17 is screwed onto the tip of the screw portion 13 and tightened.

In this case, with the shock absorber 3 and the vehicle body spring 5 set in the lower portion of the upper insulator 15, the tip portion of the screw portion 13 has the tip portion of the upper insulator 1.
The nut 17 cannot be screwed unless it protrudes from the upper side of 5. For this reason, when the shock absorber 3 and the vehicle body spring 5 are set in the lower portion of the upper insulator 15, the tip end of the screw portion 13 is set to the upper insulator 15.
The length of the threaded portion 13 is set to be long so as to penetrate and project.

When the nut 17 is screwed onto the tip of the threaded portion 13 and tightened, the shock absorber 3 moves toward the upper spring seat 21 and the body spring 5 as shown in FIG.
Attracted against the urging force of. And the body spring 5
The tightening of the nut 17 is completed in a state in which is bent by a predetermined amount. In this state, the initial load of the body spring 5 is set.

[0010]

By the way, the threaded portion 13
If the nut 17 that is fastened to the body is loosened due to vibration or the like, the initial load of the vehicle body spring 5 may change and it may not be possible to obtain a good ride comfort.
4 is required to have a loosening prevention function.

As the loosening prevention function, a double nut or a separate loosening prevention member fitted to the screw portion 13 has been proposed. However, both of them have a complicated structure and the manufacturing cost and the mounting cost are high. Is expensive.

Therefore, it is conceivable to use a caulking nut which is relatively inexpensive. This crimp nut (Japanese Patent Laid-Open No. 62-
As shown in FIG. 8, the locking screw portion 27 having a diameter L2 smaller than the inner diameter L1 of the female screw portion 25 is continuously formed at the rear end portion of the female screw portion 25 of the nut 23. ing. Then, the crimp nut 23 is attached to the screw portion 1
When it is screwed into 3, the loosening prevention screw portion 27 comes into close contact with the male screw portion of the screw portion 13 and is screwed. This prevents the crimping nut 23 from loosening.

However, as described above, the threaded portion 1
Since 3 is formed to be long in order to set the initial load of the body spring 5, when the caulking nut 23 is tightened in the screw portion 13, the locking screw portion 27 is closely attached to the male screw portion of the screw portion 13 and screwed. To meet. Therefore, the crimp nut 23
Has a large frictional resistance when tightened to the screw portion 13, and the tightening torque becomes high when tightening to a position where the initial load of the vehicle body spring 5 is obtained, resulting in poor workability. Furthermore, since the loosening prevention screw portion 27 is in close contact with the male screw portion of the screw portion 13 and screwed, there is a risk of burning.

Therefore, a so-called nylon nut in which a member made of nylon is inserted into the threaded portion has been proposed. In this nylon nut, a nylon member is inserted to increase friction, thereby preventing the nut from loosening.

With this nylon nut, seizure does not occur during tightening, and since metal and resin slide, the tightening torque is low and workability is good.

However, this nylon nut has a problem that since the nut itself is expensive, the cost for the loosening prevention function is high.

Therefore, the present invention provides a structure of a screw portion and a method of manufacturing a screw portion that can prevent the crimping nut from loosening in the final tightened state without burning even if an inexpensive crimping nut is used. For the purpose of provision.

[0018]

In order to achieve the above object, the invention according to claim 1 is formed so as to be continuous with a female thread portion and a rear end portion side of the female thread portion having a diameter smaller than the inner diameter of the female thread portion. In a structure of a screw portion to which a nut member having a lock screw is fastened, a male screw that is screwed with the female screw portion after a predetermined position from the tip of the screw portion, and the lock screw portion is caulked. Forming a small diameter portion from the tip of the threaded portion to a predetermined position that is smaller than the outer diameter of the male threaded portion, and the loosening prevention threaded portion can be screwed, and has a small diameter male threaded portion of the same type as the male threaded portion. Is characterized by.

According to a second aspect of the present invention, a nut member having a female thread portion and a locking screw portion having a diameter smaller than the inner diameter of the female thread portion and continuously formed on the rear end side of the female thread portion is fastened. In addition, in the structure of the threaded portion that is provided at the end of the piston rod of the shock absorber and penetrates the member on the vehicle body side, it is screwed with the female threaded portion after a predetermined position from the tip of the threaded portion, and the locking screw Forming a male screw portion to be caulked, and having a diameter smaller than the outer diameter of the male screw portion from the tip of the screw portion to a predetermined position, and a locking screw portion can be screwed, and is of the same type as the male screw portion. It is characterized by forming a small diameter male thread.

A third aspect of the invention is the invention according to the second aspect, wherein the shock absorber is properly attached to the vehicle body side member in a state where the loosening prevention screw portion is caulked to the male screw portion. It is characterized by being installed in a position.

According to a fourth aspect of the present invention, a nut member having a female screw portion and a locking screw portion having a diameter smaller than the inner diameter of the female screw portion and continuously formed on the rear end side of the female screw portion is fastened. In the method of manufacturing a threaded portion, after forming from the tip of the round bar to a predetermined position with a diameter smaller than the outer diameter after the predetermined position, from the tip of the round bar to the predetermined position and after the same position. A male screw is engraved to form a small-diameter male screw portion from the tip of the round bar to a predetermined position, and a male screw portion to be screwed with the female screw portion is formed after the predetermined position. There is.

The invention according to claim 5 is the invention according to claim 4, characterized in that the same type of screw is engraved at the same time from the tip of the round bar to a predetermined position and after the predetermined position. There is.

[0023]

According to the invention of claim 1, when the nut member is set in the screw portion and the nut member is rotated, the female screw portion is screwed into the small-diameter male screw portion of the screw portion, and the nut member is further rotated. And the loosening prevention screw part is screwed onto the small diameter male screw part.
When the nut member is further rotated and finally tightened as it is, the female screw portion is screwed into the male screw portion and the locking screw portion is screwed into the male screw portion. When the locking screw part is screwed into the male screw part, the contact area between the screws is widened, and moreover, since the screws are screwed in close contact with each other, friction is increased, and the nut member is tightened in the screw part in a locking state.

According to the second aspect of the present invention, when the shock absorber is set on the vehicle body side member and the nut member is screwed into the threaded portion at the end of the piston rod penetrating the vehicle body side member,
The female thread portion is screwed onto the small diameter male thread portion of the thread portion, and when the nut member is further rotated, the loosening prevention screw portion is screwed onto the small diameter male thread portion. When the nut member is further rotated and finally tightened as it is, the female screw portion is screwed into the male screw portion and the locking screw portion is screwed into the male screw portion. When the locking screw part is screwed into the male screw part, the contact area between the screws is widened, and moreover, since the screws are screwed in close contact with each other, friction is increased, and the nut member is tightened in the screw part in a locking state.

According to the invention of claim 3, when the nut member is rotated and finally tightened, the shock absorber is attracted to the member on the vehicle body side to the normal position, the female screw portion is screwed into the male screw portion, and The lock screw is screwed onto the male thread. When the locking screw part is screwed into the male screw part, the contact area between the screws is widened, and moreover, since the screws are screwed in close contact with each other, friction is increased, and the nut member is tightened in the screw part in a locking state.

According to the invention of claim 4, from the tip of the round bar to the predetermined position, the outer diameter is formed smaller than the outer diameter after the predetermined position. Next, a male screw of the same kind is engraved from the tip of the round bar to a predetermined position and after the predetermined position to form a small-diameter male screw portion from the tip of the round bar to a predetermined position, and at the predetermined position. Thereafter, a male screw portion that is screwed with the female screw portion is formed.

According to the invention of claim 5, the same type of screw is engraved at the same time from the tip of the round bar to a predetermined position and after the predetermined position.

[0028]

EXAMPLE An example of the structure of the threaded portion and the method of manufacturing the threaded portion according to the present invention will be described below. 1 is a front view showing only the screw portion 43, and FIG. 2 is a sectional view showing a strut-type suspension device 31 to which the structure of the screw portion 43 is applied. 3 and 4 are sectional views showing a state in which the crimp nut 23 is fastened to the screw portion 43. Further, FIG. 5 is a diagram showing a procedure of a manufacturing method of the screw portion 43.

First, a suspension device 31 using the structure of the screw portion according to the present invention will be described. As shown in FIG. 2, a strut-type suspension device 31 to which the structure of the screw portion according to the present invention is applied includes a shock absorber 33 having one end rotatably connected to an axle and the other end supported by a vehicle body. It has a body spring 35 whose side is supported by the shock absorber 33 and whose other end is supported by the vehicle body.

The shock absorber 33 includes a cylindrical body 37,
It is composed of a piston rod 39 which is housed in the cylindrical body 37 so as to be freely inserted and removed. A disk-shaped lower spring seat 41 is fixed to the outer periphery of the cylindrical body 37. The lower spring seat 41 includes a lower end portion 35 of the vehicle body spring 35.
a is seated. Further, a threaded portion 43 is formed at the tip of the piston rod 39, and the threaded portion 43 is formed in the opening 47 a of the base plate 47 fixed to the vehicle body side member 45.
And, the upper insulator 49 is penetrated, and the crimp nut 23 is fastened to the tip portion. The upper insulator 49 is sandwiched between the upper surface side of the base plate 47 and the vehicle body side member 45, and is screwed to the vehicle body side member 45.

A stopper plate 53 is fixed to the lower surface side of the base plate 47 via a thrust bearing 51. An upper spring seat 55 is fixed to the stopper plate 53. The upper spring seat 55 includes an inner cylinder 57, an outer cylinder 59, and an insulator rubber 61 between the inner cylinder 57 and the outer cylinder part 59. The upper end portion 35b of the body spring 35 is seated on the upper end flange portion 63 of the outer cylinder 59. Further, the bump stopper rubber 65 is attached to the piston rod 39 in the inner cylinder.
Is installed.

The lower spring seat 41 is moved to the upper spring seat 55 side by tightening the crimp nut 23 to the threaded portion 43 penetrating the upper insulator 49, and the body spring 35 is assembled in a bent state by a predetermined amount. There is.

As shown in FIG. 1, the threaded portion 43 has the crimp nut 2 after a predetermined position from the tip of the threaded portion 43.
A male screw portion 67 is formed which is screwed with the female screw portion 25 of No. 3 and the loosening prevention screw portion 27 is swaged.
From the tip of 3 to a predetermined position, the outer diameter L3 of the threaded portion 43
A smaller diameter L4 is formed, and the loosening prevention screw portion 27 can be screwed, and the same type as the male thread portion 67, that is, the same pitch and the same valley diameter, but a small diameter male thread portion 69 is formed. Further, the outer diameter L3 of the threaded portion 43 is equal to the crimp nut 2
The same size as the inner diameter L2 of the loosening prevention screw portion 27 of No. 3 or slightly longer than the inner diameter L2 is set. Therefore, when the crimp nut 23 is screwed onto the loosening prevention screw portion 27, the screw portions come into close contact with each other over a wide contact area.

As shown in FIG. 3, when the caulking nut 23 is screwed onto the tip of the threaded portion 43, the caulking nut 2
The female screw portion 25 and the loosening prevention screw portion 27 of No. 3 are loosely engaged with the small diameter male screw portion 69 of the screw portion 43. Further, as shown in FIG. 4, the female thread portion 2 of the crimp nut 23 is
5 and the loosening prevention screw portion 27 are screwed into the male thread portion 67 of the screw portion 43, the female thread portion 25 and the male thread portion 67 are in a normal meshing state, and the loosening prevention screw portion 27 is in close contact with the male thread portion 67. Engage and crimp.

Next, a method of manufacturing the screw portion 43 will be described.

As shown in FIG. 5, a long rod-shaped generatrix 71 is passed through a wire drawing die 73 to have a predetermined thickness (thickness of the threaded portion 43 in this embodiment). Next, after cutting to a predetermined length, that is, the length of the screw portion 43, one of the tip portions is formed into a small diameter from the tip portion by a predetermined length, and the small diameter portion 7
5 is formed. Next, a thread is formed by rolling. As a result, from the tip of the threaded portion 43 to a predetermined position, the diameter is smaller than the outer diameter of the male threaded portion 67 and the locking screw portion 27 is provided.
Can be screwed together to form a small-diameter male thread 69 of the same type as the male thread 67.

Next, a procedure for assembling the suspension device 31 to the vehicle body side will be described. With the body spring 35 in a free length state, the shock absorber 33 and the body spring 35 are set in the lower portion of the upper insulator 49, the threaded portion 43 of the tip end portion of the piston rod 39 is passed through the upper insulator 49, and the crimp nut is attached to the tip portion. 23 is screwed. In this state, as shown in FIG. 3, the female thread portion 25 and the locking screw portion 27 of the small diameter crimp nut 23 are
The small diameter male thread portion 69 of the thread portion 43 is loosely engaged.

By rotating the crimping nut 23 from this state, the piston rod 39 is moved to the vehicle body side and the lower spring seat 41 is moved to the upper spring seat 5.
Move to side 5. As a result, the body spring 35 bends. Then, as shown in FIG. 4, when the female screw portion 25 and the locking screw portion 27 of the crimp nut 23 are screwed into the male screw portion 67 of the screw portion 43, the female screw portion 25 and the male screw portion 67 are normally engaged with each other. The loosening prevention screw portion 27 is in close contact with the male screw portion 67, meshes with them, and is caulked. In this state, the body spring 35 is bent by a predetermined amount, and the initial load of the body spring 35 is set.

According to this embodiment, since the threaded portion 67 and the small diameter male threaded portion 69 are provided on the threaded portion 43, even when the crimping nut 23 is used, when the body spring 35 is tightened to the position where the initial load is obtained. Screw part 43 and caulking nut 2
3 does not burn. Further, in the finally tightened state, the loosening prevention screw portion 27 of the crimping nut 23 is closely attached to the male screw portion 67 and screwed, so that the crimping nut 23 can be securely prevented from loosening.

Further, until the caulking nut 23 is finally tightened, the caulking nut 23 is loosely screwed with the small diameter male thread portion 69, so that the tightening torque is reduced and the workability is improved.

Furthermore, by using the crimping nut 23, there is no need to use a separate locking mechanism,
It is possible to reduce the manufacturing cost of the suspension device 31.

[0042]

As described above, according to the first aspect of the present invention, the threaded portion and the small-diameter male threaded portion are formed in the threaded portion, so that the caulking nut can be screwed to the final tightening position. No seizure occurs, and it is possible to reliably prevent the crimping nut from loosening when it is finally tightened.

According to the second aspect of the invention, since the threaded portion and the small diameter male threaded portion are formed in the threaded portion of the piston rod tip portion, even if the caulking nut is screwed to the final tightening position, seizure occurs. It is possible to reliably prevent the crimping nut from loosening when it is finally tightened.

According to the invention of claim 3, when the nut member is rotated and finally tightened, the shock absorber is attracted to the member on the vehicle body side to the normal position, the female screw portion is screwed into the male screw portion, and The lock screw is screwed onto the male thread. When the locking screw part is screwed into the male screw part, the screwing is performed in a close contact state, so that friction is increased, and the nut member is tightened in the screw part in the locking state. Therefore,
It can securely prevent loosening.

According to the fourth aspect of the present invention, the round bar is formed to have a smaller diameter from the tip to a predetermined position than the outer diameter after the predetermined position. Next, a male screw of the same kind is engraved from the tip of the round bar to a predetermined position and after the predetermined position to form a small-diameter male screw portion from the tip of the round bar to a predetermined position, and at the predetermined position. After that, by forming the male screw portion to be screwed with the female screw portion, the screw portion can be manufactured easily and inexpensively.

According to the fifth aspect of the invention, the caulking nut can be easily manufactured by engraving the same type of male screw from the tip of the round bar to the predetermined position and after the predetermined position at the same time. In addition, the manufacturing cost can be reduced, and an inexpensive screw structure can be easily obtained.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the structure of a screw portion according to the present invention.

FIG. 2 is a cross-sectional view showing a suspension device to which the structure of the screw portion according to the present invention is applied.

FIG. 3 is a cross-sectional view showing a state in which a caulking nut is screwed onto a small-diameter male screw portion of the screw portion.

FIG. 4 is a cross-sectional view showing a state in which a caulking nut is screwed onto the male screw portion of the screw portion.

5A and 5B show a method of manufacturing a screw portion, FIG. 5A is a perspective view showing a bus bar, FIG. 5B is a perspective view showing a wire drawing step, and FIG. 5C is a perspective view showing a screw portion cut into a predetermined length. FIG. 6D is a perspective view showing a state in which the tip portion of the screw portion is formed to have a small diameter, and FIG. 6E is a perspective view showing a rolling process for forming a screw on the screw portion.

FIG. 6 is a cross-sectional view showing a suspension device using a conventional structure of a screw portion and showing a state before being mounted on the vehicle body side.

FIG. 7 is a cross-sectional view showing a suspension device using a conventional structure of a screw portion and showing a state of being mounted on the vehicle body side.

FIG. 8 is a cross-sectional view showing a crimp nut.

[Explanation of symbols]

 23 Caulking Nut 25 Female Threaded Part 27 Loosening Prevention Threaded Part 31 Suspension Device 39 Piston Rod 43 Threaded Part 67 Male Threaded Part 69 Small Diameter Male Threaded Part

Claims (5)

[Claims] 1. A structure of a threaded portion to which a nut member having a female threaded portion and a locking screw having a diameter smaller than the inner diameter of the female threaded portion and continuously formed on the rear end side of the female threaded portion is fastened. After the predetermined position from the tip of the threaded portion, form a male threaded portion that is screwed into the female threaded portion and the loosening prevention screw portion is caulked, and from the tip of the threaded portion to the prescribed position, the male threaded portion The structure of the threaded portion is characterized in that it has a smaller diameter than the outer diameter of the above, and the loosening prevention screw portion can be screwed, and a small diameter male threaded portion of the same type as the male threaded portion is formed. 2. A nut member having a female screw portion and a loosening prevention screw portion having a diameter smaller than the inner diameter of the female screw portion and continuously formed on the rear end side of the female screw portion is fastened, and at the same time, a shock absorber of the shock absorber is provided. In the structure of the threaded portion that is provided at the end of the piston rod and penetrates the vehicle body-side member, after the predetermined position from the tip of the threaded portion is screwed with the female threaded portion, the lock screw is tightened. A threaded portion is formed that has a smaller diameter than the outer diameter of the male threaded portion from the tip of the threaded portion to a predetermined position, and a locking screw can be screwed in to form a small diameter male threaded portion of the same type as the male threaded portion. The structure of the screw part characterized by doing. 3. The invention according to claim 2, wherein the shock absorber is attached to the vehicle body side member at a regular attachment position in a state where the loosening prevention screw portion is caulked to the male thread portion. The structure of the screw part characterized by that. 4. A method of manufacturing a threaded portion in which a nut member having a female threaded portion and a locking screw having a diameter smaller than the inner diameter of the female threaded portion and continuously formed on the rear end side of the female threaded portion is fastened. In the above, after forming from the tip of the round bar to a predetermined position with a smaller diameter than the outer diameter after the predetermined position, the same kind of screw is engraved from the tip of the round bar to the predetermined position and after the predetermined position. Then, a small-diameter male screw portion is formed from the tip of the round bar to a predetermined position, and a male screw portion that is screwed with the female screw portion is formed after the predetermined position. . 5. The method according to claim 4, wherein a male screw of the same kind is engraved at the same time from the tip of the round bar to a predetermined position and after the predetermined position. .