Nut equipped with washer and manufacture thereof

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to a nut with a washer and a method for manufacturing the nut, which is useful for automating the screw fastening work.

【0002】

[Conventional technology]

In recent years, automation has been promoted in all fields, and in the screw fastening work in the assembly work, the fastening work using a robot is being promoted from the conventional manual fastening work.

【0003】

In the above-mentioned screw fastening work, the "screw fastening work" in which the bolt is screwed into a member having a female screw hole is because a washer can be inserted into the screw portion of the bolt in advance to fasten the bolt. , It can be relatively easily gripped by the hand part of the robot and can be automated.

【0004】

On the other hand, in the case of "screw fastening work" in which the nut is screwed to the bolt which is inserted or integrally formed on the member side in advance, the nut and the washer are integrally screwed to the bolt. At that time, a washer with a circular outer shape and a nut with a hexagonal outer shape are gripped and fastened to the hand part of the robot at the same time, or they are shifted in time, and the washer is first inserted into the bolt with the hand part of the robot. After wearing, the nut must be screwed onto the bolt.

【0005】

In the former case, the shape and dimensions of the gripping object are completely different, which makes it very difficult to grip the robot in the hand part. On the other hand, in the latter case, the robot operation that requires time for alignment is 2 It will be doubled and the work efficiency will be significantly reduced.

【0006】

In view of this situation, a nut with a washer having a structure as shown in FIG. 4 has been proposed and used in order to rationalize the screwing of the nut to the bolt. In the case of the nut with a washer shown in FIG. 4, as shown in this figure, a step portion 2c'is formed on the washer 2'and a ring-shaped projecting piece 1a'is formed on the seat surface 1c'of the nut 1'. The washer 2'is attached to the nut 1'by forming and plastically deforming (caulking) the ring-shaped projecting piece 1a'of the nut 1'to the outer peripheral side so as to bend at a substantially right angle over the entire circumference. There is.

【0007】

[Problems to be Solved by the Invention]

However, in the structure shown in FIG. 4, in the case of a nut for high tension or a nut having a large size, the base end portion (seat surface 1c) of the projecting piece 1a'due to the large plastic deformation during the bending process. An annular crack will occur (near ), and it cannot be put into practical use. Further, in order to secure the seating surface area of the nut without increasing the outer diameter as compared with the conventional one, it is necessary to make the thickness of the projecting piece 1a'as thin as possible. In that case, if such a condition is to be satisfied, the above-mentioned cracks are more likely to occur.

【0008】

Further, in the case of the nut with a washer shown in FIG. 4, as described above, it is necessary to form a step portion 2c'to engage the nut with the washer, and if the pressure receiving area of the washer is small, 10 to There is also a problem that the reduction of the receiving pressure, which is one of the original functions of the washer, cannot be sufficiently obtained because the reduction is about 20%.

【0009】

The present invention has been made in view of the above-mentioned current situation, and provides a nut with a washer and a method for manufacturing the same, which can be applied to a nut for a high-strength bolt in terms of material and has an extremely small decrease in the pressure receiving area of the washer. The purpose.

【0010】

[Means for solving problems]

The nut with a washer according to the first invention is a nut with a washer in which the washer is rotatably and integrally attached to the nut, and the tip is at least at the tip of the ring-shaped inner peripheral surface of the washer. A ring-shaped protrusion that is plastically deformed to the enlarged diameter side so that the outer peripheral surface slides on the inner peripheral surface of the washer at least on the tip side, while forming a tapered surface with a relatively small gradient that is enlarged on the side. By forming a piece, a washer is rotatably engaged with a protruding piece of a nut.

【0011】

The nut with a washer according to the second invention is the nut with a washer according to the first invention, in which the plastic deformation of the ring-shaped protrusion of the nut toward the enlarged diameter is the circle of the ring-shaped protrusion. It is characterized in that it is partially performed at several places separated from each other.

【0012】

The method for manufacturing a nut with a washer according to the third invention is a method for manufacturing a nut with a washer in which a washer is rotatably and integrally attached to the nut, and is a ring-shaped inner peripheral surface of the washer. At least at the tip of the nut, a tapered surface with a relatively small gradient is formed on the tip side, and a ring-shaped protrusion whose outer circumference is in sliding contact with the inner peripheral surface of the washer is processed on the seat surface of the nut. The washer is formed and inserted into the protrusion of the nut so that the reduced diameter side abuts on the seat surface, and the protrusion of the nut is plastically deformed along the inner peripheral surface of the washer to expand outward. It is characterized in that a nut with a washer is manufactured in which a washer is rotatably and integrally attached to the nut by adjusting the diameter.

【0013】

[Action]

According to the nut with a washer according to the first invention, at least the tip portion of the inner peripheral surface of the washer is formed by a tapered surface having a relatively small gradient, and the protruding piece of the nut is formed by the tapered surface of the washer. By applying plastic deformation along the formed part and expanding the diameter outward, the washer is engaged to the nut, so that unreasonable plastic deformation does not occur, and therefore the base end of the nut protrusion ( A large concentrated stress does not act near the seat surface).

【0014】

Therefore, regardless of whether the nut is a high-tensile nut or a large-sized nut, cracks do not occur near the seating surface of the projecting piece of the nut, and the thickness of the projecting piece can be made extremely thin. A sufficient seating surface area for the nut can be secured.

【0015】

Further, since the pressure receiving area of the washer is hardly reduced, it is possible to sufficiently reduce the pressure receiving pressure, which is one of the original functions of the washer.

【0016】

Further, according to the nut with a washer according to the second invention, the plastic deformation of the projecting piece of the nut due to the engagement between the nut and the washer is partially caused at several places separated by the circumference of the projecting piece. Because this is done, even high-tensile nuts that are prone to cracking, for example, high-tensile nuts that are special in size or material, have almost no concentrated stress at the base end of the nut protrusion, so the nut protrusion. There is no concern that cracks will occur at the base end of the piece.

【0017】

Further, according to the nut with a washer according to the third invention, the nut with a washer according to the first and second inventions can be easily manufactured. In particular, since the washer is attached to the nut by a small plastic deformation of the projecting piece as described above, cracks do not occur even at the base end of the projecting piece of the nut, and a pressing force for deformation is applied. It is extremely small and can be mass-produced efficiently and energy-savingly with a small press.

【0018】

[Example]

Hereinafter, examples of the present invention will be described with reference to the drawings.

【0019】

FIG. 1 is a view showing a nut of a nut with a washer according to an embodiment of the present invention, (a) is a plan view, and (b) is a front view with a cross section of the right half. Further, FIG. 2 is a view showing a washer of a nut with a washer according to an embodiment of the present invention, (a) is a plan view, and (b) is a normal cross-sectional view. In addition, FIG. 3 is a diagram showing the configuration of a nut with a washer in which the washer of FIG. 2 is attached to the nut shown in FIG. 1, (a) is a plan view, (b) is a front view with a cross section of the right half, (c. ) Is a bottom view.

【0020】

In the figure, 1 is a nut, and a ring-shaped thin-walled projecting piece 1a is formed on the seat surface 1c of the nut 1. The projecting piece 1a can be formed by plastic working when the size of the nut 1 is large (specifically, when it is about 24 mm or more), and when it is smaller than that, it is cold. Further, as shown in FIG. 3A, the protruding dimension of the projecting piece 1a is configured to be slightly smaller than the thickness dimension of the washer 2 below.

【0021】

Further, in the figure, reference numeral 2 denotes a ring-shaped washer, and the inner peripheral surface 2a of the washer 2 is composed of a tapered surface having a relatively small gradient. The process of forming the inner peripheral surface 2a into a tapered surface can be performed by cutting, but it can also be easily performed by punching of the press using the draft of the press. The gradient of the inner peripheral surface 2a is such that the diameter of the inner peripheral surface 2a is reduced on the side in contact with the seat surface 1c on the nut 1 side and becomes a tapered surface on the tip side in a state of being attached to the nut 1 shown in FIG. The taper angle of the tapered surface is about 3 to 40 degrees, preferably about 5 to 30 degrees, which is a relatively small gradient. This taper angle is appropriately selected depending on the desired engagement force between the nut and the washer, and the material or size of the nut.

【0022】

Then, the washer 2 shown in FIG. 2 is placed on the projecting piece 1a of the nut 1 shown in FIG. 1 formed by the plastic processing, and the end face 2b side with the reduced diameter of the tapered surface is on the seating surface 1c side of the nut 1 as described above. As shown in FIGS. 3 (b) and 3 (c), a plurality of parts of the projecting piece 1a separated from each other by pressing or the like in the inserted state (three places in this embodiment). ), The outer peripheral surface 1d of the projecting piece 1a is pressure-deformed (plastically deformed) so as to be in sliding contact with the inner peripheral surface 2a of the washer 2, and the nut 1 and the washer 2 are engaged. In FIGS. 3 (b) and 3 (c), 1e indicates a deformed portion deformed by pressure deformation.

【0023】

During this pressure deformation, the deformed portion 1e of the projecting piece 1a and the inner peripheral surface 2a of the washer 2 are not firmly in contact with each other, that is, the outer peripheral surface 1d of the projecting piece 1a of the nut 1 and the inner peripheral surface 2a of the washer 2 It is deformed so that a slight gap 3 is formed between the two. Such pressure processing (plastic working) is performed by adjusting the stroke amount of the press and the shape of the die.

【0024】

Further, instead of the above embodiment, although not shown, the amount of deformation (plastic deformation amount) of the deformed portion 1e of the projecting piece 1a of the nut 1 that contributes to the engagement of the nut 1 and the washer 2 depends on the desired engagement force. Alternatively, depending on the material of the nut 1, it may be performed over the entire circumference of the outer peripheral surface 1d of the projecting piece 1a, it may be performed from the base end to the tip end of the projecting piece 1a, or it may be pressure-deformed so that only the tip end portion is enlarged in diameter. May be good.

【0025】

As shown in FIG. 3, the washer 2 thus locked to the nut 1 is engaged with the nut 1 so as to have a slight gap 3 between the nut 1 and the washer 2. On the other hand, since it is rotatable and the three separated points on the circumference of the nut protrusion 1a are engaged by pressure deformation, the washer 2 is always engaged without falling off from the nut 1. It is worn.

【0026】

Therefore, if the hand portion of the robot grips the nut and screwes it to the bolt side, the washer is simultaneously attached to the end face of the nut on the bolt side.

【0027】

As described above, the nut with washer according to the present embodiment is subjected to the pressure deformation required for engaging the nut 1 and the washer 2 at the minimum necessary amount, and is not subjected to unreasonable plastic deformation. Almost no concentrated stress is generated even at the base end of the projecting piece 1a. As a result, no crack is generated at the base end portion of the projecting piece 1a.

【0028】

In the case of a nut with a main washer, as described above, the inner peripheral surface 2a of the washer 2 is composed of a tapered surface having a small gradient in order to integrally engage the nut 1 and the washer 2. Since the pressure receiving area of the washer 2 is hardly reduced, it is possible to sufficiently reduce the pressure receiving pressure, which is one of the original functions of the washer, and the thickness of the projecting piece 1a of the nut 1 is also extremely thin. Therefore, the seating surface area of the nut 1 can be secured to about the same level as that of a normal nut. Therefore, the nut and the washer can be integrally engaged with each other without impairing the basic functions of the nut and the washer.

【0029】

By the way, in the above embodiment, the projecting piece 1a of the nut 1 is deformed by pressure at three separated locations on the circumference, but the nut and the washer are engaged if they are deformed at the two opposing locations at the minimum. be able to.

【0030】

Further, when a large engagement force is required for the engagement between the nut and the washer, the nut 1 may be pressure-deformed over the entire circumference of the protrusion 1a of the nut 1 as described above. It is no different from the basic operation of the present invention.

【0031】

Further, in the above embodiment, the entire inner peripheral surface 2a of the washer 2 is formed as a tapered surface, but it is predetermined from at least the tip portion of the inner peripheral surface of the washer, that is, the end surface on the enlarged diameter side of the inner peripheral surface of the washer. It may be formed only in dimensions, and even in this case, the basic operation of the present invention remains unchanged.

【0032】

[Effect of the invention]

However, according to the nuts with washers according to the first and second inventions, it can be applied to nuts for high-tensile bolts that are prone to cracks during plastic working, and automation of assembly can be applied to nuts for high-tensile tension. It can also be applied to what you use.

【0033】

Further, since the reduction in the seating surface area of the nut and the pressure receiving area of the washer is suppressed to the minimum necessary, the essential functions of the nut and the washer are not basically impaired.

【0034】

Further, according to the method for manufacturing a nut with a washer according to the present invention, the nut with a washer according to the first and second inventions can be easily and inexpensively carried out.

【0035】

Therefore, nuts with washers, which could only be used for high value-added products such as automobiles in the past, can also be used for low value-added products, greatly promoting rationalization of assembly by introducing robots. Can free workers from simple screw-tightening labor.

【0036】

Further, by using the nut with a washer according to the present invention, it becomes possible to automate the assembly under dangerous conditions such as in a submarine tunnel or a toxic gas atmosphere, which has been conventionally assembled by a worker, and labor. It can also contribute to the promotion of ensuring the safety of people.

[Simple explanation of drawings]

[Figure 1]

It is a figure which shows the nut which concerns on embodiment of this invention, (a) is a plan view, (b) is a front view which cross-section of the right half.

[Figure 2]

It is a figure which shows the washer concerning the Example of this invention, (a) is a plan view, (b) is a regular sectional view.

[Fig. 3]

It is a figure which shows the structure of the nut with a washer which attached the washer of FIG. 2 to the nut shown in FIG. 1, (a) is a plan view, (b) is a front view which cross-sectioned the right half, (c) is a bottom view. is there.

[Fig. 4]

It is a figure which shows the structure of the conventional washer nut, (a) is the front view which cross-section of the right half, (b) is the bottom view.

[Explanation of symbols]

1 ... nut 1a ... 1c ... Seat 1d ... Outer surface 2 ... washer 2a ... Inner circumference