JP2507849B2 - Nut with washer and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a washer nut useful for automating a screw fastening operation and a method for manufacturing the nut.

[0002]

2. Description of the Related Art In recent years, automation has progressed in all fields, and even in screw fastening work in assembly work,
From the conventional manual fastening work, a fastening work using a robot is being promoted.

In the above-mentioned screw fastening work, the "thread fastening work" in which a bolt is screwed to a member having a female screw hole is fastened by previously inserting a washer into the male thread of the bolt. Therefore, the robot can be relatively easily gripped by the hand portion of the robot and can be automated.

On the other hand, in the case of "screw fastening work" in which the nut is previously inserted or integrally formed on the member side, the nut is screwed to the bolt. When screwing, grasp the washer with a circular outer shape and the nut with a hexagonal outer shape at the same time and fasten it to the hand part of the robot at the same time, or shift them temporally first, and then first attach the washer with the hand part of the robot It must be inserted into the bolt and then the nut screwed onto the bolt.

In the former case, since the shape and size of the object to be grasped are completely different, it becomes very difficult to grasp in the hand part of the robot, while in the latter case, the robot which requires a long time for alignment is required. The operation is doubled, and the work efficiency is significantly reduced.

In view of the above situation, a washer nut 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 washer shown in FIG. 4, a step portion 2c 'is formed on the washer 2'and a ring-shaped protrusion 1a' is formed on the bearing surface 1c 'of the nut 1'as shown in this figure. Form the nut 1 '
By plastically deforming (caulking) the ring-shaped projecting piece 1a ′ of 1 to the outer peripheral side so as to be bent at a substantially right angle over the entire circumference,
The washer 2'is attached to the nut 1 '.

[0007]

However, in the structure shown in FIG. 4, in the case of a nut for high tension, or in the case of a large size nut, due to the large plastic deformation during the bending process, the protrusion 1a is An annular crack is generated at the base end of ′ (near the seat surface 1c ′), which cannot be put to practical use. Further, in order to secure the bearing 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 protruding piece 1a ′ as thin as possible. In this case, if the above conditions are attempted to be satisfied, the above cracks are more likely to occur.

Further, in the case of the nut with washer shown in FIG. 4, it is necessary to form the step portion 2c 'for engaging the nut with the washer as described above, and the washer has a small pressure receiving area. In that case, there is also a problem that the pressure is reduced by about 10 to 20% and one of the original functions of the washer cannot be sufficiently reduced.

The present invention has been made in view of the above situation, and provides a nut with a washer that can be applied to a nut for a high-tensile bolt due to its material, and has a very small reduction in the pressure receiving area of the washer, and a manufacturing method thereof. The purpose is to do.

[0010]

A nut with washer according to the first aspect of the present invention is a nut with washer having a washer integrally rotatably attached to the nut, and is a ring-shaped nut of the washer. A taper surface with a relatively small gradient is formed at the tip end side of the inner peripheral surface, with the diameter being expanded at the tip end side, and the diameter is expanded so that the outer peripheral surface is in sliding contact with the inner peripheral surface of the washer at least at the tip end side. In several places with a circumferential separation on the side
A washer is rotatably attached to the protrusion of the nut by forming a ring-shaped protrusion that is partially plastically deformed.

A method for manufacturing a nut with a washer according to the second aspect of the present invention is a method for manufacturing a nut with a washer in which the washer is rotatably and integrally attached to the nut, wherein the washer has a ring shape. At least the tip portion of the inner peripheral surface is formed with a taper surface having a relatively small gradient with a diameter enlarged on the front end side, and a ring-shaped protrusion whose outer peripheral surface is in sliding contact with the inner peripheral surface of the washer at the base end portion of the seat surface of the nut. the piece was processed and formed, together with the projecting piece to the reduced diameter side of the washer of the nut inserted so that it contacts the seating surface, the protrusion of the nut circumference as along the inner peripheral surface of the washer
A nut with washer having a washer integrally attached rotatably to the nut is manufactured by partially plastically deforming and expanding the diameter outward at several spaced positions .

[0012]

According to the nut with washer according to the first aspect of the present invention, at least the tip end portion of the inner peripheral surface of the washer is formed as a tapered surface having a relatively small slope, and the nut projection is formed on the washer. Since the washer is attached to the nut by applying plastic deformation along the point where the taper surface is formed and expanding the diameter outward, forcible plastic deformation is not performed, and therefore the nut projection base Large concentrated stress does not act on the edges (near the seat surface). Therefore, even with a high tension nut,
Even for large size nuts, cracks do not occur near the bearing surface of the nut protrusion, and the thickness of the protrusion can be made extremely thin, ensuring a sufficient nut bearing surface area. it can.

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

According to this nut with washer, the plastic deformation of the projection of the nut for engaging the nut and the washer is
Even if a high-tensile nut easily cracks, for example, a high-tensile nut that is special in size or material, since it is partially performed at several places on the circumference of the protrusion that are separated from each other, Since almost no concentrated stress acts on the base end, there is no concern that a crack will occur at the base end of the nut projection.

According to the washer-equipped nut of the second aspect of the invention, the washer-equipped nut of the first aspect of the invention can be easily manufactured. In particular, since the washer is attached to the nut by the small partial plastic deformation of the projecting piece as described above, the generation of cracks also disappears at the base end of the projecting piece of the nut, and The applied pressure is extremely small, and it can be mass-produced efficiently and energy-saving with a small press machine.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

1A and 1B are views showing a nut of a nut with washer according to an embodiment of the present invention. FIG. 1A is a plan view and FIG. 1B is a front view of a right half section. 2A and 2B are views showing a washer of a nut with washer according to an embodiment of the present invention. FIG. 2A is a plan view and FIG. 2B is a front sectional view. 3 is a diagram showing the structure of a nut with 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 in which the right half is sectioned, (c) )
Is a bottom view.

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

In the figure, 2 is a ring-shaped washer, and the inner peripheral surface 2a of this washer 2 is a tapered surface having a relatively small slope. The processing of forming the inner peripheral surface 2a as a tapered surface can be performed by cutting, but can also be easily performed by punching of the press using the draft of the press. The inclination of the inner peripheral surface 2a is such that the seat surface on the nut 1 side in the state of being attached to the nut 1 shown in FIG.
The tapered surface has a taper angle of about 3 to 40 degrees, preferably about 5 to 30 degrees, so that the diameter of the tapered surface is reduced on the side in contact with 1c and expanded on the tip side. ing. This taper angle is appropriately selected depending on the desired engaging force between the nut and the washer, and the material or size of the nut.

Then, the washer 2 shown in FIG. 2 is attached to the projecting piece 1a of the nut 1 shown in FIG. 1 formed by the plastic working.
As shown in FIGS. 3 (b) and 3 (c), the taper surface is inserted so that the end surface 2b side having the reduced diameter is located on the seat surface 1c side of the nut 1, and the press-fitting is performed in this inserted state. Like this this piece
A plurality of spaced portions on the circumference of 1a (three in this embodiment)
Then, 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 with each other. In FIGS. 3 (b) and 3 (c), 1e indicates a deformed portion deformed by pressure deformation.

Upon this pressure deformation, the deformed portion 1e of the protruding piece 1a
And the inner peripheral surface 2a of the washer 2 do not contact firmly, that is,
The nut 1 is deformed so that a slight gap 3 is formed between the outer peripheral surface 1d of the projecting piece 1a and the inner peripheral surface 2a of the washer 2. Such pressure working (plastic working) is performed by adjusting the stroke amount of the press and the shape of the die.

Although not shown in the above embodiment, the deformation amount (plastic deformation amount) of the deformed portion 1e of the projecting piece 1a of the nut 1 which contributes to the engagement of the nut 1 and the washer 2 is not shown. It may be performed over the entire circumference of the outer peripheral surface 1d of the protruding piece 1a depending on the engaging force or the material of the nut 1.
It may be performed from the base end to the tip of 1a, or may be deformed under pressure so that only the tip portion is expanded in diameter.

Thus, the washer 2 locked to the nut 1 in this way has the nut 1 and the washer 2 as shown in FIG.
Since it is attached so as to have a slight gap 3 between the two, it is rotatable with respect to the nut 1,
Since the three spaced apart positions on the circumference of 1a are engaged by being deformed under pressure, the washer 2 is always attached without falling off from the nut 1.

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

As described above, in the nut with washer according to this embodiment, the pressurizing deformation necessary for engaging the nut 1 and the washer 2 is carried out to the minimum necessary amount, and the unreasonable plastic deformation is not carried out. Therefore, concentrated stress hardly occurs at the base end portion of the projecting piece 1a of the nut 1. As a result, cracks do not occur at the base end of the projecting piece 1a.

In the case of the nut with the washer, as described above, the inner peripheral surface 2a of the washer 2 is a tapered surface having a small slope in order to integrally engage the nut 1 and the washer 2. Therefore, since the pressure receiving area of the washer 2 hardly decreases, it is possible to sufficiently reduce the pressure receiving which is one of the original functions of the washer, and the thickness of the protrusion 1a of the nut 1 is extremely small. Since the nut 1 can be made thin, the bearing surface area of the nut 1 can be secured to about the same level as a normal nut. Therefore, it is possible to integrally attach the nut and the washer without substantially impairing the basic functions of the nut and the washer.

By the way, in the above-mentioned embodiment, the three spaced apart locations on the circumference of the projecting piece 1a of the nut 1 are deformed under pressure. You can tie it.

When a large engaging force is required to engage the nut and the washer, the protrusion 1a of the nut 1 may be pressed and deformed over the entire circumference as described above. Even in the above, there is no change in the basic operation of the present invention.

Further, in the above embodiment, the inner peripheral surface of the washer 2 is
Although the entire 2a is formed into a tapered surface, it may be formed to have a predetermined size from at least the tip end portion of the inner peripheral surface of the washer, that is, the end surface of the inner peripheral surface of the washer on the enlarged diameter side. The basic operation of the present invention remains unchanged.

[0030]

As described above, according to the nut with washer of the first aspect of the present invention, it can be applied to the nut for high tension bolt which is apt to crack during the plastic working, and the assembling can be automated for high tension. It can also be applied to those that use nuts.

Since the reduction of the bearing surface area of the nut and the pressure receiving area of the washer can be suppressed to the necessary minimum, the essential functions of the nut and the washer are not basically impaired.

Further, according to the method for manufacturing the nut with washer according to the second aspect of the present invention, the nut with washer according to the first aspect of the invention can be implemented easily and at low cost.

Therefore, the nut with washer, which can be used only for high value-added products such as automobiles, can be used for low value-added products, and the rationalization of the assembly by the introduction of the robot is greatly improved. Can be promoted to free workers from simple screwing labor.

Further, when the nut with washer according to the present invention is used, it is possible to automate the assembly under dangerous conditions such as a submarine tunnel or a toxic gas atmosphere which has been conventionally assembled by an operator. It also contributes to the promotion of ensuring the safety of workers.

[Brief description of drawings]

1A and 1B are views showing a nut according to an embodiment of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a front view in which the right half is sectioned.

FIG. 2 is a diagram showing a washer according to an embodiment of the present invention,
(a) is a plan view and (b) is a front sectional view.

3 is a diagram showing the structure of a nut with 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 in which the right half is sectioned, (c) Is a bottom view.

FIG. 4 is a view showing the structure of a conventional nut with washer, (a)
Is a front view in which the right half is sectioned, and (b) is a bottom view.

[Explanation of symbols]

 1 ... Nut 1a ... Projection piece 1c ... Seat surface 1d ... Outer surface 2 ... Washer 2a ... Inner surface

Claims (2)

(57) [Claims] 1. A nut with a washer having a washer integrally rotatably attached to the nut, wherein the washer has a ring-shaped inner peripheral surface, and a diameter of the washer is relatively increased on the tip side. A tapered surface with a small slope is formed, and the nut outer surface is circumferentially separated from the seat surface of the nut so that the outer peripheral surface slides on the inner peripheral surface of the washer at least at the tip side.
A washer nut characterized in that a washer is rotatably attached to the nut protrusion by forming a ring-shaped protrusion that is partially plastically deformed at several places . 2. A method for manufacturing a nut with a washer, wherein a washer is rotatably integrally attached to the nut, wherein a diameter of the washer is expanded at least at a tip end portion of a ring-shaped inner peripheral surface of the washer. In addition to forming a tapered surface with a relatively small gradient, a ring-shaped projection piece whose outer periphery is in sliding contact with the inner peripheral surface of the washer at its base end is formed on the seat surface of the nut, and the nut projection piece is formed as described above. Insert the washer so that the reduced diameter side comes into contact with the seat surface, and at the same time, extend the nut projection piece outward by plastically deforming it partially at several circumferential positions along the inner surface of the washer. A washer-equipped nut in which a washer is rotatably integrally attached to a nut by manufacturing a nut, and a method for producing the same.