JP2002181019A - Shaft force visual confirmation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft force visual confirmation device capable of visually observing a degree of shaft force to recognize it precisely. SOLUTION: This shaft force visual confirmation device is constituted such that a ringlike elastic body 30 is arranged between a tightened body 50 and a nut 20 in a bolt 10 and the nut 20 tightening the tightened body 50 and a fixed width of an outer peripheral end part of the elastic body 30 is classified by color different from that on an inner peripheral side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for visually recognizing axial force when two members to be fastened are combined and fastened to each other using bolts and nuts.

[0002]

2. Description of the Related Art There are bolts and nuts as machine element parts for fastening parts such as machines or structures. Its basic function is to generate an axial force in the bolt axis direction by tightening the nut, thereby strongly restraining the object to be fastened. Although the specifications of bolts and nuts are defined by JIS, etc., in setting these specifications, rigidity and impact are determined by determining the external force acting on the object to be fastened and verifying the stress generated inside the bolts and nuts. Bolts and nuts with specifications that satisfy strength requirements such as characteristics and durability are selected. In order for bolts and nuts to function properly, it is important to control the axial force generated by tightening the bolts and nuts to an appropriate value. It is practically difficult to directly measure the axial force generated in an arbitrary tightened state, and the axial force is estimated by the following method or the like. (1) A method of converting the axial force from the amount of deformation by measuring the amount of deformation of the bolt. (2) A method of converting an axial force from a tightening torque or a rotation angle at the time of tightening. As a practical example of (1), (a) a strain gauge is embedded in a bolt, a minute elongation of the bolt generated by the axial force is detected using a measuring amplifier or the like, and the generated stress is converted from the amount of elongation. Further, there is a method of converting to an axial force, (b) a method of measuring the elongation of a bolt by ultrasonic waves or the like, converting the generated stress from the amount of elongation, and further converting the stress to an axial force.
As a practical example of (2), (a) using a torque wrench,
A method of converting torque into axial force from various conditions such as friction, geometrical and mechanical relationships (hereinafter referred to as torque method),
(B) There is a method of converting the axial force by using a device for measuring the amount of rotation of the nut and taking into account the amount of advance of the nut according to the amount of rotation of the nut.

[0003]

The above-mentioned methods (1) and (a) require processing for embedding strain gauges in bolts and nuts, which is costly. In the methods (1) and (2), an expensive measuring device is required. The above (2)
The method (a) requires a device for measuring the amount of rotation of the nut. In addition, the above (1) (a), (1) (b),
(2) The method (b) is not easy to measure. Therefore, the most popular method in practical use is the torque method (2) (a). However, when the tightening torque is measured using a torque wrench instead of directly managing the axial force by the torque method, and the measured values are used to manage the axial forces of the bolts and nuts, there are the following problems. In order to convert the tightening torque into the axial force, the degree of the axial force cannot be directly visually observed, so that a dynamic conversion formula is used. This conversion formula includes the friction coefficient as a variable. The applied axial force is also different. In other words, even if the bolts and nuts are tightened with the specified torque, if the actual friction coefficient is higher than the conversion-type friction coefficient, insufficient axial force will be generated, and the bolts and nuts will loosen, loosened fasteners, etc. Problem may occur. Conversely, if the actual friction coefficient is lower than the conversion-type friction coefficient, an excessive axial force is generated, which may lead to plastic deformation and breakage of the bolt. Generally, bolts and nuts are used in any environment.
It is used by any worker, and the coefficient of friction is affected by friction conditions such as lubrication, surface roughness, and adhesion of dust, so that it is not easy to manage the coefficient of friction to a specific value. Further, it is not easy to estimate the coefficient of friction by observing the state of the contact surface. That is,
It is difficult to accurately measure the axial force. An object of the present invention is to provide an axial force visually recognizing device capable of visually observing the degree of axial force with high accuracy. Another object of the present invention is to provide, in addition to the above objects, an axial force visual recognition device capable of knowing the degree of axial force at low cost.

[0004]

The present invention to achieve the above object is as follows. (1) When fastening an object to be fastened with a bolt and a nut, a ring-shaped elastic body is disposed between the object to be fastened and the nut, and the elastic body has a constant width at an outer peripheral end. The axial force visual recognition device is characterized in that is colored differently from the inner peripheral side. (2) The axial force visual recognition device according to (1), wherein the elastic body is colored such that the color of a certain width at the outer peripheral end is blue based and the inner peripheral side is colored red. (3) The axial force visual recognition device according to (1) or (2), wherein a washer is disposed between the nut and the elastic body. (4) The axial force visual recognition device according to (3), wherein the elastic body has a ring-shaped convex portion formed on an upper surface and a lower surface thereof so as to be fitted with the nut and the washer. (5) The axial force visual recognition device according to (3) or (4), wherein the nut and the washer are connected so as not to be misaligned in the radial direction and rotatably in the circumferential direction. (6) The body to be fastened is an automobile wheel, and the body to be fastened and the elastic body are fastened via a wheel nut, (1), (2), or (3);
Or the axial force visual recognition device according to (4) or (5).

[0005] In the axial force visual recognition device of the above (1), an elastic body is arranged between the nut and the object to be fastened because a certain width of the outer peripheral end is colored differently from the inner peripheral side. The elastic body is compressed corresponding to the axial force generated by the elastic member. Since the amount of compression (deformation) depends on the elastic properties of the elastic body, by selecting and using an elastic body having appropriate elastic properties, the axial force generated in the bolt is used as the amount of deformation of the elastic body. Can be measured directly by visual observation. In addition, the relationship between the axial force of the bolt and the amount of deformation of the elastic body is measured and grasped in advance, the deformation amount of the elastic body when the elastic body is actually used is measured, and color coding is performed so as to correspond to the deformation amount. By determining the width of the determined outer peripheral end, the degree of the axial force can be easily and accurately known. In addition, the main deformed portion of the elastic body is a portion that is not in contact with the object to be fastened, the bolt, and the nut. You can know. Also, when measuring the amount of deformation of the bolt, there is no need for a special device such as the case of measuring with a strain gauge or ultrasonic waves, and the degree of the axial force can be obtained simply by visually checking the amount of deformation of the elastic body when the axial force occurs. And no expensive and special equipment is required. Also, since it is only using an elastic body,
It is cheap. In the axial force visual recognition device of the above (2), the outer peripheral end portion which is color-coded is a blue type, and the inner peripheral side is a red type. Therefore, when the blue type is visible, it is safe and appropriate. You can instantly and easily recognize the image as if it were too tight and dangerous. In the axial force visual recognition device of the above (3), since the washer is arranged between the nut and the elastic body, it is possible to prevent the rotational force from the bolt and the nut from being directly applied to the elastic body. In the axial force visual recognition device of the above (4), since the convex portion on the ring that fits with the nut and the washer is formed on the upper surface and the lower surface of the elastic body, there is no radial misalignment. You can see the power.
In the axial force visual recognition device of the above (5), the nut and the washer are rotatably connected in the circumferential direction so as not to be misaligned in the radial direction. In the axial force visual recognition device of the above (6), an excellent effect can be obtained particularly for fastening an automobile wheel.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the axial force visual recognition device according to the embodiment of the present invention includes a bolt 10, a nut 20, and a fastened body 50 (for example, 50a is a disk of an automobile wheel, and 50b is a hub of a vehicle). ) And a ring-shaped elastic body 30 arranged between the nut 20.
The device for visually recognizing axial force according to the embodiment of the present invention may further include a washer 40 disposed between the nut 20 and the elastic body 30.

[0007] The bolt 10 has a head 11 and a shaft 12. A male screw 12a is formed on at least the outer peripheral portion of the distal end portion in the length direction of the shaft portion 12. The length of the shaft portion 12 is longer than the thickness of the combined body of the fastened bodies 50, and a part of the male screw 12 a protrudes from the fastened body 50. On the inner peripheral portion of the nut 20, a female screw 21 which can be screwed with the male screw 12a of the bolt 10 is formed. The axial length of the nut 20 is smaller than the axial length of the male screw 12a.

The elastic body 30 is made of an elastic material and is made of, for example, rubber. The elastic body 30 has a ring shape as shown in FIGS. 5 and 6, and the constant width W of the outer peripheral end portion 30a is
0b and different colors. For example, it is desirable that the outer peripheral end 30a be blue and the inner peripheral side is red. this is,
Because the color sensation is fixed on a daily basis, such as a red signal is dangerous and a green signal is safe, it is easier to recognize if the colors are classified into such colors.

The elastic body 30 includes a bolt 10, a nut 20,
The elastic modulus of the bolt 10, the nut 20, the washer 40, and the body 50 to be fastened when an axial force is generated is smaller than that of the washer 40 and the body 50 to be fastened. It is negligible compared to the amount of deformation of the elastic body 30. The elastic body 30 is disposed between the fastened body 50 and the nut 20 via the washer 40. Elastic body 30
The relationship between the force applied in the axial direction and the amount of deformation of the elastic body 30 due to the force is measured and grasped before being disposed between the nut 20 and the object 50 to be fastened.

As shown in FIG. 6, the elastic body 30 has a thickness L in the axial direction and an outer diameter D in the radial direction when no axial force is applied. When an axial force is applied to the elastic body 30, the elastic body 30 is compressed, and the thickness L of the elastic body 30 in the axial direction decreases by ΔL, and the outer diameter D increases in the radial direction by ΔD. Therefore, dimensional changes ΔL and ΔD occur. The elastic body 30 is provided when the appropriate axial force of the vehicle wheel is generated in the shaft portion 12 of the bolt 10, for example.
The swelling is larger in the radial direction than the outer periphery of 0, and a bluish color can be visually observed. Further tightening the nut 20 and increasing the axial force,
It is possible to confirm the color of the red system by passing through the region of the constant width of the blue system. In this case, it is set so that the red color can be confirmed when the axial force exceeds the appropriate value.If you check the color of this red color, it is dangerous to overtighten,
Tighten until only blue color is visible. Elastic body 3
0 indicates that when an axial force is applied to the elastic body 30, there is a gap between the inner diameter surface of the elastic body and the outer diameter surface of the bolt shaft, and the bolt 10
Is not in contact with the shaft portion 12. It is preferable that ring-shaped convex portions 30c and 30d for positioning in a radial direction with the washer 40 and the nut 60 are formed on the upper surface and the lower surface of the elastic body 30, respectively. However, this convex portion 30c,
30d does not necessarily have to be formed.

The washer 40 is made of metal or hard resin.
It is ring-shaped. The washer 40 includes the nut 20 and the elastic body 30.
And placed between. The inner diameter of the washer 40 is larger than the inner diameter of the nut 20, and is desirably smaller than the inner diameter of the elastic body 30. The outer diameter of the washer 40 is larger than the outer diameter of the elastic body when no axial force is applied. The washer 40 has seat surfaces 41 and 42. In addition, washer 4
A fitting groove 40 a that fits with the convex portion of the elastic body 30 is formed in the lower seating surface 41 in the circumferential direction. In addition, washer 4
It is desirable for the positioning in the radial direction that the fitting projection 40c to be fitted with the nut 12 is formed in the circumferential direction on the upper seat surface 42 of the 0, but it is not always necessary.

On the lower surface of the nut 20, there is provided a concave groove 20a which is formed so that the groove width becomes larger as it goes deeper than an opening for rotatably coupling with the washer 30 in the circumferential direction. ing. The coupling between the groove 20a and the washer 40 is performed by, for example, fitting the convex portion 40c of the washer 40 into the groove 20a and then caulking lightly enough to rotate in the circumferential direction.

The object 50 includes two or more members, 50
a and 50b, 50a is a disk for large and medium-sized wheels used for trucks, buses and the like among automobile wheels. A nut seat 50c is formed on the disc 50a, and is fastened by a wheel nut 60 interposed between the disc 50a and the elastic body 30. Wheel nut 6
The lower surface 60a of the wheel 0 is spherically formed so as to correspond to the nut seat 50c of the disk 50a for an automobile wheel. However, the wheel nut may be a flat nut depending on the mounting method. The washer 40, the elastic body 30, and the wheel nut 60 are respectively provided with concave grooves 60b and 40a,
Although they are fitted by d and 30c, it is also effective to fix them with an adhesive or the like so that they do not fall apart as needed.

Next, the operation of the present invention will be described. As shown in FIG. 1, when no axial force is generated in the shaft portion 12 of the bolt 10, the elastic body 30 has a thickness L in the axial direction and an outer diameter D. From this state, the bolt 10 and the nut 20 are tightened to generate an axial force. Due to the generation of the axial force, as shown in FIG. 2, the elastic body 30 is pressed by the washer 40 and the fastened body 50 that are in contact with each other, and the thickness in the axial direction decreases from L to ΔL (shrinkage). ), Outer diameter from D to △ D
It only grows (swells).

The degree of the axial force applied to the bolt 10 and the nut 20 is determined by the position of the outer diameter surface of the elastic body 30 bulging outward in the radial direction (the degree of overhang) as follows.
You can know. When the outer diameter of the elastic body 30 is smaller than the outer diameter of the washer 40, it can be visually recognized that the tightening of the bolt 10 and the nut 20 is weak (the axial force is small). When the outer diameter of the elastic body 30 is larger than the outer diameter of the washer 40 and only the blue color is visible, the bolt 10 and the nut 20 are tightened with an appropriate axial force.
Further, when the bolt 10 is tightened and the red color can be viewed, the nut 20 is excessively tightened (the axial force is excessive), so that the nut 20 is loosened so that only the blue color can be viewed.

Since the outer diameter of the second seat surface 42 of the washer 40 is circular, the elastic body 30 is prevented from wrapping around the nut 20 over the entire circumference regardless of the hexagonal shape of the nut 20. The elastic body 30 can be deformed only in the axial direction and the radial direction, and the degree of the axial force can be visually observed as the amount of deformation of the elastic body 30 with high accuracy.
The illustrated example shows a case where a washer 40 made of a separate member from the nut 20 is used. By setting the friction coefficient between the washer 40 and the nut 20 to be smaller than the friction coefficient between the washer 40 and the elastic body 30, when the nut 20 is rotated by applying torque, the space between the nut 20 and the washer 40 rotates. Washer 40
And the elastic body 30 can be prevented from rotating, and unreasonable torque can be prevented from being applied to the elastic body 30. Thereby, it is possible to prevent the elastic body 30 from being deformed in the rotation direction and changing the dimensions in the axial direction and the radial direction,
The accuracy of the axial force determination can be kept good. However, the outer diameter of the seating surface 22 of the nut 20 on the object 50 side has a shape (for example, a circular shape) that can prevent the elastic body 30 from wrapping around the nut 20 side. 3
If the frictional force between the nut 20 and the nut 20 is small,
It is not necessary to use 0.

Further, since the elastic body 30 is arranged between the body 50 to be fastened and the washer 40, for example, when a shocking load or a repetitive load on a rough road is applied to the fastening portion, the elastic body 30 is elastically elastic. The body 30 can absorb the impact, the load, and the like, and can reduce the damage and the influence of the impact, the load, and the like on the fastening portion. Therefore, the impact resistance of the wheel is improved, and the weight of the wheel can be reduced. Further, since the elastic body 30 can absorb vibrations generated during traveling or the like, the life of the peripheral parts of the elastic body 30 is extended, the vibration is reduced, noise generated by the vibration is reduced, and the bolt 10 and the nut 20 are loosened. Actions such as prevention can be obtained. Also,
Since the elastic body 30 is provided, even if plastic deformation such as buckling or settling occurs in the bolt 10, the nut 20, and the fastened body 50, the influence on the elastic body 30 is small, and the axial force is appropriate. Kept at the value.

[0018]

According to the axial force visual recognition device of the first aspect, since the elastic body whose fixed width at the outer peripheral end is colored differently from the inner peripheral side is disposed between the nut and the object to be fastened. The elastic body is compressed corresponding to the axial force generated by the tightening. Since the amount of compression (deformation) depends on the elastic properties of the elastic body, by selecting and using an elastic body having appropriate elastic properties, the axial force generated in the bolt is reduced by the amount of deformation of the elastic body. Can be measured directly by visual observation. In addition, the relationship between the axial force of the bolt and the deformation amount of the elastic body is measured and grasped in advance, and the deformation amount of the elastic body when the elastic body is actually used is measured.
By determining the width of the color-coded outer peripheral end, the degree of the axial force can be easily and accurately known. In addition, since the main deformed portion of the elastic body is a portion that is not in contact with the object to be fastened, the bolt, and the nut, there is no error in the measured axial force due to the surface condition thereof, and the degree of the axial force can be accurately determined. You can know. Also, when measuring the amount of deformation of the bolt, there is no need for a special device such as the case of measuring with a strain gauge or ultrasonic waves, and the degree of the axial force can be obtained simply by visually checking the amount of deformation of the elastic body when the axial force occurs. And no expensive and special equipment is required. In addition, since only an elastic body is used, the cost is low. In the axial force visual recognition device according to the second aspect, since the outer peripheral end portion that is color-coded is a blue type and the inner peripheral side is a red type, it is safe and appropriate when the blue type is visible, and dangerous when the red type is visible. You can instantly and easily recognize it visually, as if it were too tight to be dangerous. According to the axial force visual recognition device of the third aspect, since the washer is arranged between the nut and the elastic body, it is possible to prevent the rotational force from the bolt and the nut from being directly applied to the elastic body. In the axial force visual recognition device according to the fourth aspect, since the convex portion on the ring that fits with the nut and the washer is formed on the upper surface and the lower surface of the elastic body, there is no radial misalignment. Can be visually recognized.
In the axial force visual recognition device according to the fifth aspect, the nut and the washer are rotatably connected in the circumferential direction so as not to be misaligned in the radial direction. According to the axial force visual recognition device of the sixth aspect, it is possible to obtain an excellent effect particularly for fastening an automobile wheel.

[Brief description of the drawings]

FIG. 1 is a plan view of an axial force visual recognition device according to an embodiment of the present invention in a state where no axial force is generated.

FIG. 2 is a cross-sectional view of the axial force visual recognition device according to the embodiment of the present invention in a state where no axial force is generated.

FIG. 3 is a plan view of the axial force visual recognition device according to the embodiment of the present invention in a state where an axial force is generated.

FIG. 4 is a sectional view of the axial force visual recognition device according to the embodiment of the present invention in a state where an axial force is generated.

FIG. 5 is a plan view of an elastic body used in the embodiment of the present invention.

FIG. 6 is a detailed sectional view of the elastic body used in the embodiment of the present invention in a state where no axial force is generated.

FIG. 7 is a detailed sectional view of the elastic body used in the embodiment of the present invention in a state where an axial force is generated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Bolt 20 Nut 30 Elastic body 30a Blue color 30c, 30d Convex part 40 Washer 50 Workpiece 50a Automobile disk 50b Vehicle hub 60 Wheel nut

Claims (6)

[Claims] When an object to be fastened is fastened by a bolt and a nut, a ring-shaped elastic body is arranged between the object to be fastened and the nut, and the elastic body is fixed at an outer peripheral end thereof. An axial force visual recognition device characterized in that the width is colored differently from the inner peripheral side. 2. The axial force visually recognizing device according to claim 1, wherein the elastic body has a constant width color at an outer peripheral end and a red color at an inner peripheral side. 3. The device for visually recognizing axial force according to claim 1, wherein a washer is arranged between the nut and the elastic body. 4. The axial force visual recognition device according to claim 3, wherein the elastic body has a ring-shaped convex portion formed on the upper surface and the lower surface thereof to be fitted with the nut and the washer. 5. The axial force visual recognition device according to claim 3, wherein the nut and the washer are connected so as not to be misaligned in a radial direction and rotatably in a circumferential direction. 6. The object to be fastened is an automobile wheel,
The axial force according to claim 1, claim 2, claim 3, claim 4, or claim 5, wherein the member to be fastened and the elastic body are fastened via a wheel nut. Visual recognition device.