JPH0228266Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a tightening force management device that can detect 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 bolts, 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 coming out of the case is provided to protrude from the inner surface of the case.

The case or the movable washer is provided with an index portion that indicates the load applied to the disc spring by displaying the relative axial position of the movable washer as the disc spring is deflected.

[Effect]

In the tightening force management device configured as described above, each bolt is inserted 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. In this case, if the relationship between the deflection of the disc spring and the load is determined in advance and displayed on the above indicator, the amount of movement of the movable washer due to the deflection of the disc spring during tightening, that is, the effect on the bolt. The axial force can be easily and accurately read. Moreover, disc springs can provide a large load capacity in a small space in the load direction, and because they are combined in series, they are not only able to simply manage the tightening force, but are also effective in preventing loosening.

〔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 belleville 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 one movable washer 3 from coming off. This stopper part 14 is formed by machining the opening edge of the case 2 into a step or by bending the edge inward, and the large diameter part 3a of the washer hits this stopper part 14. This prevents the washer 3 from popping out from the case 2. In addition, as shown in FIG. 1, the large diameter portion 3a is located at the stopper portion
4, the small diameter portion 3b of the washer projects to the outside of the case 2.

An index portion 16 is provided on the small diameter portion 3b of the movable washer 3, that is, on the outer peripheral surface of the portion that projects outward from the case 2. This index portion 16 is used to determine the relative position of the movable washer 3 in the axial direction with respect to the case 2, that is, the load corresponding to the deflection of the disc spring 12. It is now possible to read the numerical values etc. The scale of this index part 16 is
The read value indicates the load applied to the disc spring 12, that is, the tightening force of the bolt.

In the tightening force management device 1 having the above configuration, a bolt 20 is inserted as illustrated in FIG. 2, and the bolt 20 is screwed into a female thread of a nut (not shown) or the like. When the bolt 20 or nut is tightened by a predetermined amount, the disc spring 12 is compressed between the washers 3 and 4.
The member to be tightened 21 is tightened by the reaction force. The tightening force at this time can be easily determined by reading the scale of the index portion 16 on the end surface 2a of the case. In this case, since the axial force acting on the bolt 20 is directly read, the tightening force can be managed accurately.

Furthermore, even if the surface to be tightened becomes sagging, the deflection of the disc spring 12 absorbs it, so that it is not only possible to simply detect the tightening force, but also to prevent the bolt from loosening. In addition, changes in tightening force over time,
Changes due to heat cytology, impact, etc. can also be monitored.

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,
This prevents deterioration and loss 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 FIG. 3 shows another embodiment of the present invention. In this case, an index section 16 representing the load is provided on the outer peripheral surface of the case 2, and this index section 16
A slit 25 is formed in the case 2 along. A pointing member 26 projects from the inside of the slit 25 and is configured to move along the slit 25. This instruction member 26 is
As illustrated in FIG. 4, it is provided in a protruding manner on the movable side washer 3. That is, in this case, the instruction member 26 is
As shown in FIG. 5, it has a threaded portion 27 at one end, and is fixed by screwing this threaded portion 27 into a screw hole (not shown) provided in the movable washer 3. However, other fixing means may also be used.

In order to prevent the inside of the case 2 from being exposed to the outside atmosphere, it may be desirable to make the slit 25 as small as possible or take measures such as covering it with a cover made of a transparent material.
Further, the indicator portion 16 may be a plate or sheet-like member attached to the case 2 or the movable washer 3 by gluing, welding, riveting, or the like.

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

[Effect of idea]

According to the present invention, the tightening force of the bolt can be checked and adjusted as desired, and also has the effect of preventing the bolt from loosening.

[Brief explanation of drawings]

Fig. 1 is a partially sectional front view of an embodiment of the present invention, Fig. 2 is a sectional view showing how the tightening force management device shown in Fig. 1 is used, and Fig. 3 is a partial cross-sectional view of an embodiment of the present invention. FIG. 4 is a partially sectional front view of the embodiment of
FIG. 5 is a perspective view showing the movable side washer in the figure, and FIG. 5 is a perspective view showing the indicating member in FIG. 4. 1... Tightening force tube device, 2... Case, 3...
Movable side washer, 4... Fixed side washer, 6, 7... Hole for bolt insertion, 12... Belleville spring, 14... Stopper part, 16... Indicator 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 hole for bolt insertion in the center; a plurality of disc springs housed in series between the washers in the case; and an inner surface of the case. A stopper portion is provided to protrude to the side and prevent the movable washer from coming out of the case, and a stopper portion is provided on the case or the movable washer to control the relative axial position of the movable washer as the disc spring is deflected. 1. A tightening force management device comprising: an indicator section that indicates a load applied to a disc spring by displaying the indicator section.