JP3086084B2 - Retightening torque measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tightening torque measuring apparatus for measuring a tightening torque value, wherein a screw (bolt, nut, etc.) which has been once tightened or has already been tightened is turned again in a tightening direction to increase the tightening torque. The torque value at the time of rotation start when tightening is electrically processed, or the time of rotation start is estimated by the computer from the electrical output of the gyroscope, and the torque value at the time of rotation start is measured. The present invention relates to a torque measuring device.

[0002]

BACKGROUND OF THE INVENTION For mounting screws for tightening important security parts such as around an engine of an automobile and around a foot, for example,
Additional tightening is required to ensure the tightening of the mounting screws. At the time of retightening, when the screw (bolt, nut, etc.) once tightened is to be turned again in the tightening direction, the screw does not rotate until the tightening torque value of the screw is reached, but the tightening is performed. When a torque greater than the torque value is applied, the torque is increased. Generally, immediately after the start of rotation of the screw at the time of retightening, the torque value decreases and the screw is further tightened, and the torque value (inertia torque) increases. (Refer to the curve A in FIG. 3) Conventionally, to measure the torque value immediately after the start of rotation, the torque wrench is tightened and rotated, and at that time, the start of rotation of the screw is sensed with the feel of the hand and the rotation of the torque wrench is stopped Then, the additional tightening torque value at that time was measured.

[0003]

However, with this measuring means, there are many artificial measurement errors and skill differences due to the manual labor of the operator, and it is impossible to perform highly reliable measurement. Furthermore, the phenomenon that the torque value decreases immediately after the screw starts rotating may be due to the fact that the torque value does not always decrease but may continue to increase depending on the material and shape of the screw or the tightened object. It has been difficult to accurately measure the tightening torque value.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has as its object to provide a reliable tightening torque measuring device with high measurement accuracy. It is.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings.

FIG. 1 shows a wrench provided with a re-tightening torque measuring device according to the present embodiment. Reference numeral 1 denotes a wrench main body, and the wrench main body 1 has a gyroscope 3 provided on an upper part of its head end. A handle 2 is formed at the tail end. The lower part of the head end includes a torsion part, that is, a torque detector 5, and a torque sensor as the strain gauge 4 is mounted on the torque detector 5. Further, the lower end of the torque detecting section 5 has a shaft section 6 having a square cross section, and a box wrench 7 selected according to the standard size of the head 8 of the bolt is engaged with the shaft section 6 having the square cross section. .

If the handle 2 is rotated to tighten the bolts, the wrench is twisted at the torque detecting portion 5 until the bolt starts to rotate, and the torque value is detected by the strain gauge 4 mounted on the detecting portion 5. , The point at which it starts to turn can be detected with a gyroscope. In the drawing, reference numeral 9 denotes an object to be fastened, and reference numeral 10 denotes an object to be fastened. The object 9 to be fastened is fixed to the object 10 by screws (bolts in this case).

The above is the configuration of the present embodiment. Next, the operation thereof will be described with reference to a block diagram shown in FIG. 2 and a characteristic diagram shown in FIG.

The torque value by the above-described strain gauge 4 when the screw is tightened is sent to an amplifier (amplifier) 21 as a weak electric signal, amplified, and then sent to an AD converter 22. The analog amount is converted into a digital amount by the AD converter 22 and sent to the computer 30 for data processing.

On the other hand, the gyroscope 3 at the time of retightening
Is amplified by an amplifier (amplifier) 26 and sent to an AD converter 27, where it is converted into a digital quantity and sent to a computer 30 for data processing.

Since the zero point of the strain gauge 4 and the gyroscope 3 slightly fluctuates due to the characteristics of the strain gauge itself and the surrounding environmental conditions such as temperature, the zero adjustment is performed by software of the computer 30 at the time of measurement.

In FIG. 3, the point S (time ts) is the voltage of the bolt 8
Is the rotation start point at the time of retightening. That is, when the tightening operation is started, the torque value continues to increase to the point S, but the bolt 8
Does not rotate (start), the wrench is twisted at the torque detector, and the strain gauge 4 (FIG. 1) operates. During this time, the gyroscope 3 is theoretically immovable and does not act. However, in practice, the gyroscope waveform shown by the line B in FIG.
When the torque value is further increased, the bolt 8 starts rotating at the point S, but at that moment, the gyroscope 3 also starts to rapidly start. However, in the waveform B of the above-mentioned gyroscope, it is difficult to discriminate a point at which a manual shake and a sudden start to be started are determined. In addition, a reliable torque value at the rotation starting point S and a slightly reduced torque value after the rotation is started can be accurately measured.

[0013]

As described above, the present invention relates to a tightening torque measuring device for measuring a torque value at the time of starting rotation by turning a screw (bolt, nut, etc.) for measuring a tightening torque value with a wrench. , A torque sensor and a gyroscope are mounted on a wrench, and the torque sensor and the gyroscope are electrically processed to measure the torque value at the time of starting rotation. According to the gyroscope 3 attached to the wrench main body 1 and the rotation start point is estimated by a computer based on the waveform of the gyroscope, the torque value at the time of rotation start when the screws (bolts, nuts, etc.) are tightened is increased. And the torque value that slightly decreases after the rotation starts
There is an effect that can be measured accurately and reliably.

[Brief description of the drawings]

FIG. 1 is a structural explanatory view of a tightening torque measuring device according to an embodiment of the present invention.

FIG. 2 is a block diagram for measuring a rotation starting torque value according to the embodiment of the present invention.

FIG. 3 is a graph showing a relationship between a gyroscope and a torque by a computer in an operation process of the embodiment of the present invention.

[Description of Signs] 1 ... Wrench body 2 ... Handle 3 ... Gyroscope 4 ... Strain gauge
(Torque sensor) 5: Torque detector 6: Shaft 7: Box wrench 8: Bolt 9: Fastened object 10: Fastened object 21: Amplifier 22: AD converter 26: Amplifier 27: AD converter 30: Computer

Claims (2)

(57) [Claims] 1. A tightening torque measuring device for measuring a torque value at the time of starting rotation by rotating a screw (bolt, nut, etc.) for measuring a tightening torque value with a wrench, wherein the wrench has a torque sensor and a gyroscope. And a torque measuring device that electrically processes values measured by the torque sensor and the gyroscope to measure a torque value at the time of starting rotation. 2. The retightening torque measuring device according to claim 1, wherein the electrical output of the gyroscope is directly input to a computer to estimate the time when the retightening rotation is started. .