JPH0228267Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a tightening force management device capable of detecting the tightening force of bolts, nuts, etc.

[Conventional technology]

BACKGROUND OF THE INVENTION As the various types of equipment that use fasteners, such as bolts and nuts, become more complex and of higher quality, there is an increasing need to control their tightening force with high precision.

Conventionally, as a simple means of controlling tightening force,
Bolts and the like have been tightened to a predetermined torque using a so-called torque wrench.

Further, there are also bolts that can directly detect the axial force acting on the bolt, such as the shaft-shaped fastener shown in Japanese Patent Application Laid-Open No. 57-90414.

[Problem that the invention attempts to solve]

However, when tightening a bolt with the torque wrench, the axial force applied to the bolt is not directly read, but the axial force is simply estimated from the magnitude of the tightening torque. For this reason, there are naturally limits to the management of tightening force based on torque, such as the relationship between torque and axial force fluctuating due to various factors specific to the bolt.

On the other hand, rod-shaped fasteners that can directly detect the axial force applied to the bolt, such as the rod-shaped fasteners seen in JP-A No. 57-90414, are highly reliable, but the bolts (fasteners) themselves require special and advanced processing. is required, making it difficult and expensive to manufacture.

Another problem is that even if the tightening force is controlled at the time the bolt is tightened, over time the bolt or tightening surface may become loose due to fatigue, and the tightening force may not be exerted. There was something I didn't do.

[Means for solving problems]

The tightening force management device of the present invention includes a cylindrical case that is open at both ends, and the opening at one end of the case is movable in the axial direction of the case and has a hole in the center for inserting a bolt. A movable side washer is provided. Furthermore, the opening on the other end of the case is provided with a fixed side washer that also has a hole for bolt insertion in the center, and a plurality of disc springs are installed between this fixed side washer and the movable side washer. housed in series. Further, a stopper portion for preventing the movable washer from slipping out of the case is provided to protrude from the inner surface of the case.

A pointer having a short arm and a long arm is pivotally supported on the case, the short arm of the pointer is locked to a movable washer, and a scale is provided at the position indicated by the long arm.

[Effect]

In the tightening force management device configured as described above, each bolt is passed through the case, the washer, and the disc spring, and is screwed into a nut or the like and tightened, thereby compressing and bending each disc spring. As the disc spring bends, the movable washer moves relative to the case, moves the short arm of the pointer, and the movement is magnified by the long arm, pointing to the scale. Therefore, by displaying the load applied to the disc spring on the scale based on the relationship between the load and deflection of the disc spring and the relationship with the arm length of the pointer, the axial force acting on the bolt can be easily and accurately read. be able to.

〔Example〕

In the tightening force management device 1 shown in FIG. 1, the case 2 has a short cylindrical shape and is open at both ends. A suitable material for the case 2 is a corrosion-resistant metal such as stainless steel. However, other metals may also be used.

Washers 3 and 4 are provided at the openings at both ends of the case 2. Holes 6, 7 for bolt insertion are formed in the center of each washer 3, 4. The surfaces of these washers 3 and 4 are subjected to appropriate heat treatment to increase their hardness so as not to impair the function of the disc spring 12 described below.

One of the washers 3 is provided so as to be movable in the axial direction of the case 2. This movable side washer 3
is a large diameter portion 3a located on the inside side of the case 2;
It consists of a small diameter part 3b located on the outside side. The other washer 4 is fixed to the case 2 by caulking the end 9 of the case 2 toward the inner surface. This fixed side washer 4 may be fixed by welding or screwing.

Further, inside the case 2, a plurality of disc springs 12 are housed between the washers 3 and 4 in an unloaded or compressed state. The disc springs 12 are stacked in series with alternate orientations. Grease is applied between the disc springs 12 or between the disc springs 12 and the washers 3 and 4. The spring characteristics of the disc spring 12 are designed so that even if it becomes flat, it remains within the allowable stress range, and can be used repeatedly.

A stopper portion 14 is provided to prevent the movable washer 3 from coming off. This stopper part 14 is formed by machining the opening edge of the case 2 to form a step or by bending the edge inward, and the large diameter part 3a of the washer hits this stopper part 14. This means that the movable washer 3 is connected to the case 2.
I'm trying not to jump out. In addition, as shown in FIG.
In this state, the small diameter portion 3b of the washer 3 protrudes to the outside of the case 2.

A pointer 16 is rotatably attached to the case 2 by a shaft 17. The pointer 16 has a short arm 16a and a long arm 16b having different lengths from the shaft 17.
A portion (fulcrum) 18 located between 6a and 16b is pivotally supported by a shaft 17.

A locking portion 19 formed at the end of the short arm portion 16a is locked to the movable washer 3 via the protrusion 20. This protrusion 20 has a threaded portion 21 at one end as illustrated in FIG.
It is fixed by screwing into the screw hole 22 provided in the movable side washer 3. However, other fixing means may be used. The locking portion 19 may be any member as long as the protrusion 20 can fit therein, and specifically, it may be a through hole, a recess, a notch, or the like.

Further, a scale portion 25 is provided at a position indicated by the tip of the long arm portion 16b. This scale part 2
5 is based on the relationship between the load and deflection of the disk spring 12 and the relationship between the length ratio from the axis 17 of the short arm section 16a and the long arm section 16b. Numerical values, etc. (not shown) are displayed so that they are pointed to.

The scale portion 25 may be drawn directly on the outer circumferential surface of the case 2, but it may also be in the form of a plate or a seal and fixed to the case 2 by adhesive, welding, riveting, or the like.

As shown in FIG.
0 into a nut or screw hole (not shown). When the bolt 30 is tightened by a predetermined amount, the disc spring 12 is compressed between the washers 3 and 4, and the member 31 to be tightened is tightened by the reaction force. The disc spring 12 is bent in response to this tightening force, and the movable washer 3 is moved in the axial direction with respect to the case 2. This movement of the washer 3 causes the short arm portion 16a to rotate around the shaft 17, and this movement is magnified by the long arm portion 16b and displayed on the scale portion 25. In this way, the load applied to the disc spring 12, that is, the axial force of the bolt 30, can be easily known by reading the scale section 25, and even if the disc spring 12 with small deflection is used, its displacement can be enlarged and clearly displayed. .

Moreover, according to the above-mentioned device, even if the surface to be tightened is sagging after the bolt 30 is tightened, this can be absorbed by the deflection of the disc spring 12, so that it is possible to not only detect the tightening force but also to It can also exhibit a loosening effect. It is also possible to monitor changes in tightening force over time, changes due to heat cycles, impacts, etc.

In addition, since the disc spring 12 is housed in a space that is almost sealed by the case 2 and coated with grease or anti-corrosion paint, it will not get caught in sand even if it is used in a harsh atmosphere exposed to dust or rain. , corrosion,
Prevents deterioration and leakage of grease, resulting in high reliability. By selecting the materials of the case 2, washers 3, 4, disc spring 12, etc., a device with excellent heat resistance, low temperature resistance, and corrosion resistance can be obtained.

Note that when implementing the present invention, the number of plate springs 12 may be changed as necessary.

[Effect of idea]

According to the present invention, the tightening force of the bolt can be confirmed or arbitrarily adjusted, and it also has the effect of preventing the bolt from loosening.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional front view of an embodiment of the present invention, Fig. 2 is a perspective view of the movable side washer and pointer shown in Fig. 1, and Fig. 3 is the same as shown in Fig. 1. FIG. 3 is a sectional view showing how the tightening force management device is used. 1...Tightening force management device, 2...Case, 3...
...Movable side washer, 4...Fixed side washer, 6, 7...Bolt insertion hole, 12...Disc spring, 14...Stopper part, 16...Pointer, 16a...Short arm part, 1
6b...long arm part, 17...shaft, 25...scale part.

Claims (1)

[Scope of utility model registration request] A cylindrical case with both ends open; a movable washer that is movable in the axial direction of the case at the opening at one end of the case and has a hole for inserting a bolt in the center; A fixed side washer fixed to the opening on the other end side and having a bolt insertion hole in the center, a plurality of disc springs housed in series between the washers in the case, and an inner side of the case. a stopper part provided protruding from a side surface to prevent the movable side washer from coming out of the case; a short arm part and a long arm part; a part between these two arm parts is pivotally supported by the case; A tightening force management device comprising: a pointer whose short arm is latched to the movable washer; and a scale provided in the case at a position indicated by the long arm.