JP2021156335A - Looseness preventing bolt and manufacturing method thereof - Google Patents

Abstract

To make a female screw and a male screw of a looseness preventing ring closely adhere to each other in not only load side flanks but also loose side flanks, to exhibit large looseness preventing action stably.SOLUTION: On the outer periphery of a looseness preventing ring 4 mounted in a middle part of a bolt shaft part 2 in an axial direction, a male screw 4a continuous with a male screw 2a of the bolt shaft part 2 is formed. The male screw 4a of the looseness preventing ring 4 has a larger screw diameter than the male screw 2a of the bolt shaft part 2. The male screw (4a) of the looseness preventing ring 4 can elastically deform so that it is in close contact with a female screw 5a to which the bolt shaft part 2 is screwed on both a loose side flank and a load side flank.SELECTED DRAWING: Figure 1

Description

The present invention relates to a locking bolt having a locking structure, and a method for manufacturing the same.

Patent Document 1 discloses a bolt with a locking ring that can prevent loosening without using a washer or the like. This conventional bolt is provided with an endless annular groove having a predetermined width on the outer circumference of the threaded portion of the screw shaft, and a synthetic resin locking ring having an outer diameter almost the same as the outer diameter of the male thread is fitted in this groove. .. By integrating the bolt and the locking ring in this way, it is possible to reduce the time and effort required for tightening and the risk of loss.

Microfilm of Judgment No. 60-195860 (Gazette No. 62-100324)

In the prior art disclosed in Patent Document 1, the outer diameter of the locking ring is substantially the same as the screw outer diameter of the screw shaft, and when the bolt is tightened, the outer circumference of the locking ring is along the spiral direction by the female screw. A thread groove is formed on the outer circumference of the lock ring by being scraped off. Therefore, the outer diameter of the male screw formed on the outer circumference of the locking ring is substantially the same as the outer diameter of the screw of the screw shaft.

On page 4, lines 1 to 13, of Patent Document 1, "The anti-loosening effect of this ring 6 is a mechanical property peculiar to plastics made of a polymer substance as a main raw material, that is, plastic deformation due to an external force. This is because it has an appropriate elastic deformation. Therefore, after applying an external force and screwing it into the screw hole, elastic deformation that restores the original shape with the passage of time occurs and the resin comes into strong contact with the female screw. When using this bolt with a locking ring of this invention, if it is forcibly screwed into a predetermined screw hole with a strong force, a spiral groove will be formed on the outer peripheral surface of the ring 6 by the female screw of the screw hole. It comes into close contact with the female screw through the ring 6 without a gap, and does not loosen due to the vibration or impact of the machine. "

However, since the outer diameter of the screw of the locking ring is almost the same as the outer diameter of the screw of the screw shaft, the play side flanks of the male screw and the female screw do not adhere to each other, or even if they adhere to each other, they adhere to each other. The force should be smaller. It is understood that the description in Patent Document 1 refers to the adhesion between the load-side flanks of the male and female threads.

Further, according to the above-mentioned conventional technique, a screw is not formed on the outer periphery of the locking ring before mounting on the screw hole, and a female screw is formed on the outer periphery of the locking ring by forcibly screwing the bolt into the screw hole. Form. Therefore, when the bolt is screwed into the screw hole, a large amount of shavings from the locking ring is generated, and the shavings are interposed between the male screw and the female screw. The presence of such shavings impairs the stability of the fastening state, and the shavings deteriorate over a long period of time to reduce the fastening torque, which may cause loosening of bolts.

It is an object of the present disclosure to provide a bolt with an anti-loosening ring capable of stably exhibiting a more excellent anti-loosening effect, and a method for manufacturing the same.

The locking bolt according to the present disclosure includes a bolt shaft portion having a male screw formed on the outer periphery thereof, a groove portion formed in the middle portion of the bolt shaft portion in the axial direction, and a locking ring mounted on the groove portion. ..

On the outer circumference of the lock ring, a male screw continuous with the male screw of the bolt shaft portion may be formed.

The male screw of the locking ring may have a larger screw diameter than the male screw of the bolt shaft portion.

The male screw of the locking ring may be elastically deformable so as to be in close contact with the female screw to which the bolt shaft portion is screwed on both the play side flank and the load side flank.

In addition, the method for manufacturing the locking bolt according to the present disclosure is as follows.
A step of simultaneously forming the male threads of both the bolt shaft portion and the locking ring by rolling, and
The screw diameter of the male screw of the anti-loosening ring has a step of becoming larger after rolling than at the time of rolling due to the elastic restoring force of the anti-loosening ring itself.

Further, the method for manufacturing the locking bolt according to the present disclosure is described.
A step of forming the tip of the bolt shaft into a tapered shape before forming the male screw, and a step of forming the tip of the bolt shaft into a tapered shape.
Before forming the male screw on the bolt shaft portion and the locking ring, the bolt shaft portion is inserted into the locking ring from the tapered tip portion to insert the locking ring into the groove portion. Steps to install and
May have more.

Preferably, the lock ring has a higher elasticity than the bolt shaft portion.

According to the anti-loosening bolt according to the present disclosure, the female screw and the male screw of the anti-loosening ring are in close contact with each other not only between the flanks on the load side but also between the flanks on the play side, and a large anti-loosening action can be stably exhibited.

Further, according to the method for manufacturing a locking bolt according to the present disclosure, a bolt having the locking ring can be efficiently manufactured. Furthermore, if the anti-loosening ring is attached to the bolt shaft before the male screw is formed on the bolt shaft, the anti-loosening ring will not be caught by the male screw on the outer periphery of the bolt shaft during the attachment, facilitating the mounting work. can. Further, by processing the tip portion of the bolt shaft portion into a tapered shape, the work of inserting the bolt shaft portion into the locking ring can be smoothly performed.

FIG. 1 is a semi-cross-sectional side view of a locking bolt according to an embodiment of the present invention. .. FIG. 2 is a cross-sectional view showing a state in which the locking bolt is attached to the screw hole. FIG. 3 is a side view showing a process of mounting the locking ring on the bolt shaft portion before forming the male screw. FIG. 4 is a side view showing a state in which the locking ring is attached to the bolt shaft portion (however, before the formation of the male screw). FIG. 5 is a side view showing an embodiment using the ring mounting jig. FIG. 6 is a vertical cross-sectional view of a locking bolt when a male screw is formed by rolling.

FIG. 5 shows a locking bolt 1 according to an embodiment of the invention. The locking bolt 1 includes a bolt shaft portion 2, a bolt head 3 integrally provided at the base end portion of the shaft portion 2, and a locking ring 4 mounted in the middle portion in the axial direction of the shaft portion 2. ing.

A male screw 2a is formed on the outer periphery of the shaft portion 2 from the tip portion to a predetermined range in the axial direction, and an annular groove portion 2b is formed in the middle portion in the axial direction of the male screw 2a formation range.

The locking ring 4 is fitted in the groove 2b, and a male screw 4a having a spiral shape continuous with the spiral shape of the male screw 2a of the shaft portion 2 is formed on the outer periphery of the locking ring 4. The axial length of the groove 2b and the ring 4 mounted in the groove 2b is preferably larger than one pitch of the male threads 2a and 4a and smaller than two pitches. The male threads 2a and 4a may be multi-threaded threads, but single-threaded threads are suitable for forming at least one pitch of male threads 4a on the outer periphery of the ring 4 having a relatively small axial length.

The molding material of the bolt shaft portion 2 is preferably steel or stainless steel, but other appropriate alloys such as titanium alloys and synthetic resin materials can also be used, and carbon fiber reinforced composite materials can also be used.

The bolt head 3 may have a hexagonal column, a cylinder, or any other appropriate shape. Further, a tool engaging groove such as a sliding hole, a cross hole, a hexagonal hole, or a square hole may be formed on the top surface of the bolt head 3. When the bolt head 3 is not provided, a similar tool engaging groove can be formed on the base end surface of the shaft portion 2.

The male screw 4a of the locking ring 4 has a larger screw diameter than the male screw 2a of the shaft portion 2, and the locking ring 4 has restoring elasticity against compression in the radial and axial directions, and has a locking function due to its characteristics. It is configured to exert.

The molding material of the anti-loosening ring 6 may be an appropriate one, and may be, for example, a thermosetting elastomer, a thermoplastic elastomer, 66 nylon, 6 nylon, a polyamide 66, or the like, or a mixed material thereof. You may. Further, as long as it has the restoring elasticity necessary for achieving the object of the present invention, an appropriate synthetic resin material other than the elastomer, for example, a polycarbonate resin material, a polypropylene resin material, a phenol resin material, an epoxy resin material, or a polyurethane resin material Etc. can also be used.

As the thermosetting elastomer, natural rubber or synthetic rubber (including the resin-based elastomer in the present specification) can be used. Synthetic rubbers include isoprene rubber, butadiene rubber, styrene / butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene, ethylenepropylene rubber, chlorosulfonated polyethylene, acrylic rubber, fluororubber, epichlorohydrin rubber, urethane rubber or silicone rubber. Can be used.

As the thermoplastic elastomer, polystyrene-based elastomers, olefin / alken-based elastomers, polyvinyl chloride-based elastomers, polyurethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, and the like can be used.

In the locking bolt 1 according to the present embodiment, the screw diameter of the male screw 4a of the locking ring 4 is slightly larger than the screw diameter of the male screw 2a of the shaft portion 2. More specifically, the outer diameter of the thread top of the male screw 4a is slightly larger than the outer diameter of the thread top of the male screw 2a, and the diameter of the thread root of the male screw 4a is the male screw. It is slightly larger than the thread valley diameter of the thread valley bottom of 2a. Preferably, the screw diameter of the male screw 2a of the shaft portion 2 is smaller than the screw diameter of the screw hole 5 to which the shaft portion 2 is screwed, and the screw diameter of the male screw 4a of the locking ring 4 is the screw diameter of the screw hole 5. Larger than the screw diameter.

FIG. 2 shows a state in which the locking bolt 1 is fastened to the screw hole 5. The male screw 2a of the shaft portion 2 and the female screw 5a of the screw hole 5 are in contact with each other on the load side flanks, but the play side flanks are slightly separated from each other. On the other hand, the male screw 4a of the locking ring 4 and the female screw 5a of the screw hole 5 are in contact with each other on the load side flanks, and are also in contact with each other on the play side flanks. When the lock ring 4 is screwed into the screw hole 5, it is compressed from the outer peripheral side by the female screw 5a and elastically slightly reduced in diameter, and the elastic restoring force of the ring 4 itself causes the load side of the male screw 4a. And the flank on the play side are in close contact with the corresponding flank of the female screw 5a. As a result, a large anti-loosening effect is exhibited.

Hereinafter, a suitable manufacturing method of the locking ring 1 will be described. First, as shown in FIG. 3, as an intermediate product of a bolt having a bolt shaft portion 2A and a bolt head 3 in which a male screw is not formed but a groove portion 2b is formed, and an intermediate product in which a male screw is not formed. Manufacture a locking ring 4A. As shown in the figure, it is preferable that the tip portion of the bolt shaft portion 2A is formed in a tapered shape that gradually reduces in diameter toward the tip side.

Next, as shown in FIG. 4, the ring 4A is attached to the groove portion 2b by inserting the bolt shaft portion 2A into the locking ring 4A from the tapered tip portion. At this time, it is preferable that the outer peripheral portion of the ring 4A protrudes outward in the radial direction from the outer peripheral surface of the bolt shaft portion 2A.

All the work of attaching the ring 4A to the bolt shaft portion 2A may be performed manually, but as shown in FIG. 5, it can also be performed using the ring attachment jig 7. The ring mounting jig 7 has an insertion hole 7a through which the bolt shaft portion 2A can be inserted, and a ring installation recess 7b which is concentrically provided at the opening end of the insertion hole 7a and has a diameter larger than that of the insertion hole 7a. As shown in the figure, the ring 4A is installed in the ring installation recess 7b, and the bolt shaft portion 2A is inserted into the ring 4A from the tip portion to easily and quickly mount the ring 4A. Can be done.

The axial width of the ring 4A is more preferably larger than the groove portion 2b. As a result, in a state where the ring 4A is mounted in the groove 2b, the ring 4A is in close contact with both sides of the groove 2b in the axial direction, the formation of the male screw 4a in the rolling process described later is stabilized, and the male screw 4a is formed. It is possible to prevent the locking ring 4 from moving in the axial direction in the groove 2b after the formation.

Next, as shown in FIG. 6, the shaft portion 2 having the male threads 2a and 4a is formed by simultaneously forming the male threads 2a and 4a on the outer peripheral surfaces of the shaft portion 2A and the ring 4A using the rolled dies 8 and 9. And ring 4. The rolling dies 8 and 9 are a reciprocating type in which a bolt shaft portion is sandwiched between two flat dies to form a male screw, and a rotation 2 in which a bolt shaft portion is sandwiched between two round dies to form a male screw. It may be a roll type or a segment type in which a bolt shaft is sandwiched between a round die and an arch-shaped segment die arranged on the outer side of the circumference to form a male screw, and other appropriate rolling methods are adopted. can.

At the time of rolling, both the outer peripheral surfaces of the shaft portion 2A and the ring 4A are pressed from the outer peripheral side by the rolling dies 8 and 9, and a male screw 2a is formed on the outer peripheral surface of the shaft portion 2A by plastic deformation. On the other hand, the ring 4A is elastically reduced in diameter, and a male screw 4a is formed on the outer periphery of the ring 4A by plastic deformation or cutting with dies 8 and 9.

In order to form the male screw 2a by plastic deformation of the outer peripheral portion of the ring 4A made of an elastic material, it depends on the molding material of the ring 4A, but in the case of a material whose plasticity increases by heating, it is prior to the rolling process. It is preferable to heat the ring 4A to increase the plasticity of the ring 4A.

As shown in FIG. 6, the screw diameter of the male screw 4a of the ring 4 in the rolling process is equal to the screw diameter of the male screw 2a of the shaft portion 2. However, when the bolt 1 is taken out from the rolling dies 8 and 9 after rolling, the external force for reducing the diameter of the ring 4 is released, so that the ring 4 is slightly reduced as shown in FIG. 1 due to the elastic restoring force of the ring 4 itself. The diameter of the male screw 4a of the ring 4 is increased to be larger than the diameter of the male screw 2a of the bolt shaft portion 2.

According to the present embodiment, since the male screw 4a is formed in advance on the outer periphery of the lock ring 4 by rolling, a large amount of shavings are not generated when the bolt 1 is fastened to the screw hole 5, and the screw is fastened. Since the torque is stabilized and the effect of the shavings interposed between the male and female threads deteriorating with the passage of time is small, the loosening prevention effect can be maintained even after a long period of time.

Further, since the male threads 2a and 4a are simultaneously formed on the outer circumferences of the shaft portion 2A and the locking ring 4A by rolling, the number of steps for forming the male threads 2a and 4a can be reduced and the productivity is improved.

Further, by processing the tip portion of the shaft portion 2A into a tapered shape, the locking ring 4A can be easily and quickly attached.

Further, since the ring 4A is attached to the shaft portion 2A on which the male screw 2a is not formed, the male screw that causes catching when the ring 4A is attached to the shaft portion 2A does not exist in the shaft portion 2A, and the male screw can be easily attached. Can be installed.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and the design can be changed as appropriate. .. For example, the bolt head 3 may not be provided. Further, the cross-sectional shape of the locking ring 4 and the groove 2b may be an appropriate shape such as a semicircle or a triangle, and the cross-sectional shape of the locking ring 4 and the groove 2b are different. May be good. Further, in the manufacturing method according to the above embodiment, the ring 4 is attached to the shaft portion 2 before forming the male threads 2a and 4a, but after forming the male threads 2a and 4a on the shaft portion 2 and the ring 4 in advance, the male threads 4a are attached. The ring 4 to be held may be attached to the shaft portion 2.

1 Loosening prevention bolt 2 Bolt shaft part 2A Bolt shaft part as an intermediate product before male screw formation 2a Male screw 2b Groove part 4 Loosening prevention ring 4A Loosening prevention ring as an intermediate product before male screw formation 4a Male screw

Claims (3)

A bolt shaft portion (2) having a male screw (2a) formed on the outer circumference, a groove portion (2b) formed in the middle portion of the bolt shaft portion (2) in the axial direction, and looseness attached to the groove portion (2b). In the locking bolt (1) having the retaining ring (4) and
A male screw (4a) continuous with the male screw (2a) of the bolt shaft portion (2) is formed on the outer periphery of the locking ring (4), and the male screw (4a) of the locking ring (4) is formed. The male screw (4a) of the lock ring (4) has a screw diameter larger than that of the male screw (2a) of the bolt shaft portion (2), and the female screw (5a) to which the bolt shaft portion (2) is screwed. ), The loosening prevention bolt is configured to be elastically deformable so that it adheres to both the play side flank and the load side flank. The method for manufacturing a locking bolt (1) according to claim 1.
A step of simultaneously forming the male threads (2a, 4a) of both the bolt shaft portion (2) and the locking ring (4) by rolling, and
The screw diameter of the male screw (4a) of the locking ring (4) has a step of becoming larger after rolling than during rolling due to the elastic restoring force of the locking ring (4) itself. Characteristic,
How to manufacture anti-loosening bolts. A step of forming the tip of the bolt shaft (2A) into a tapered shape before forming the male screw (2a).
Before forming the male threads (2a, 4a) on the bolt shaft portion (2) and the locking ring (4), the bolt shaft portion (2A) is pulled from the tapered tip portion to the locking ring (4A). ) To attach the lock ring (4A) to the groove (2b) by inserting it into the groove (2b).
The method for manufacturing a locking bolt according to claim 2, further comprising.

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