JPH08193896A - Torque detector - Google Patents

Abstract

PURPOSE: To accurately measure a clamping torque by providing a strain detector for detecting the torsional strain of the rotary part of a rotary clamping tool and a signal processor rotatably through impact absorbing means at the rotary part of the tool. CONSTITUTION: The end of an impact wrench 1 is coupled to a socket 2 with a shaft 3, and a cylindrical sensor case 4 integrally rotatable with the shaft 3 is provided at the outside of the shaft 3 via impact absorbing means 5a to 5d. A battery 10, a processor 11 and a display unit 12 are built in the case 4, and a strain gage 13 adhered to the surface of the shaft 3 is connected to the processor 11 with leads 14. The shaft 3 and the socket 2 are repeatedly rotated and abruptly stopped by the impact torque generated at the wrench 1 to clamp a bolt 15. When the shaft 3 is abruptly stopped, the impact is directly transmitted to the socket 2 and the bolt 15, but not directly transmitted to the case 4 due to the means 5a to 5d. Thus, the torque measurement with high reliability is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention measures the tightening torque of a rotary tightening tool from the torsional stress generated on a shaft, which is the rotating part of the rotary tightening tool, when a bolt or the like is tightened by the rotary tightening tool. The present invention relates to a torque detector.

[0002]

2. Description of the Related Art As a method for measuring the tightening torque when tightening bolts and nuts, a strain gauge is attached to the rotating part of a rotary tightening tool as shown in FIG. A common method is to process the applied electrical signal. When torque is generated by the rotary tightening tool 16 and torque is transmitted through the shaft 17 and the socket 18 to tighten the bolt 19, torsion stress is generated in the shaft 17 and the socket 18. The strain gauge 20 detects this stress as torsional strain. The electric signal detected by the strain gauge 20 passes through the amplifier section 22 of the external processing device 21, is processed by the processing section 23, and the processing result is displayed on the display section 24.
An electrical signal is transmitted from the strain gauge 20 attached to the rotating shaft 17 to the external processing device 21 by using a slip ring 25 having a mechanical contact portion or a brush.

By the way, as disclosed in Japanese Utility Model Laid-Open No. 55-142274, transmission of an electric signal from a strain gauge to an external processing device is mechanically performed in addition to a mechanical contact portion such as a slip ring. It is also known to use a rotary transformer or the like having no contact portion. Further, as disclosed in Japanese Unexamined Patent Publication No. 5-134769, there is known a device that uses a magnetostrictive torque sensor instead of a strain gauge to achieve downsizing and high accuracy of the device.

[0004]

As a characteristic of an electric signal transmitting portion connecting a strain detecting member such as a strain gauge or a magnetostrictive torque sensor provided in a rotating portion and an external processing device, for example, in a contact portion of a slip ring or the like. The electrical signal transmission becomes unstable due to the vibration of the machine, etc. Also, although there is no mechanical contact part in the rotating transformer etc., the amplitude of the AC voltage induced by the impact changes and the noise and disturbance occur in the electrical signal transmission. It will be. That is, there is a problem that the accurate tightening torque cannot be measured for a rotary tightening tool accompanied by vibration that tightens with an intermittent / impact torque such as an impact wrench.

As a measure to solve this problem, as shown in FIG. 4, the processing section 23 provided in the external processing device,
It is conceivable to integrate the display unit 24 with the battery 26 into the shaft 17 and omit the slip ring and the rotary transformer, which are vulnerable to vibration and shock. However, in this case, many electronic devices that are extremely vulnerable to impact will be built in the rotating part, so if the vibration or impact generated by the rotary tightening tool is directly transmitted to the rotating part, the built-in electronic device will be damaged. I'm afraid.

According to the present invention, the signal processing section composed of electronic equipment is integrally rotatably connected to the rotating section through the shock absorbing means, so that the rotational tightening can be performed even when vibration or shock is generated by the rotating tightening tool. The purpose is to reliably and accurately measure the tightening torque of the tool.

[0007]

The means adopted in claim 1 as means for achieving the above object is a strain detecting portion for detecting a torsional strain of a rotating portion provided in a rotating portion of a rotary tightening tool. And a torque detecting device for a rotary tightening tool, which comprises a signal processing unit that is integrally rotatable with the rotating unit via a shock absorbing means.

[0008]

In the torque detecting device having the above-mentioned structure, since the signal processing unit rotates integrally with the rotating unit via the shock absorbing means, the vibration and impact generated by the rotary tightening tool are directly processed. It is not transmitted to the club.

[0009]

EXAMPLES Next, examples of the present invention will be described below. 1 and 2 exemplify the outline of a torque detection device for carrying out the present invention. The tip of the impact wrench 1 and the socket 2 are connected by a shaft 3, and the shaft 3 transmits the impact torque generated by the impact wrench 1 to the socket 2. On the outside of the shaft 3, the shaft 3
A cylindrical sensor case 4 that is integrally rotatable with is provided via impact absorbing means 5a, 5b, 5c, and 5d.

The shock absorbing means 5a, 5b, 5c, 5d are
Convex portions 6a, 6b, 6c, 6d provided on the shaft 3
And concave portions 7a, 7b, 7c, 7 provided in the sensor case 4 so as to accommodate the convex portions 6a, 6b, 6c, 6d.
d, the convex portions 6a, 6b, 6c, 6d and the concave portion 7
The springs 8a, 8b, 8c, 8d (the convex member 6) arranged in the shaft rotation direction between a, 7b, 7c, 7d.
c, 6d and the springs provided between the recesses 7c, 7d of the sensor case 4 are not shown in the figure), and the vibration transmission between the shaft 3 and the sensor case 4 is blocked. Here, the shaft 3 may be provided with a concave portion, the sensor case 4 may be provided with a convex portion, and the sensor case 4 may be coupled via a spring therebetween. Further, as a shock absorbing means, the concave portion may be filled with a liquid such as oil, and the convex portion may be provided with an orifice in the rotational direction to absorb the shock between the shaft 3 and the sensor case 4.

A bearing 9 is provided between the sensor case 4 and the shaft 3 so that the sensor case 4 can rotate relative to the shaft 3 about the same axis as the shaft.

The sensor case 4 includes a battery 10 and a processing unit 1.
1. The display unit 12 is built in, and the strain gauge 13 attached to the surface of the shaft 3 and the processing unit 11 are connected by a lead wire 14. The length of the lead wire 14 is determined in consideration of the turning range of the rotating part which is restricted by the shock absorbing means, and since the lead wire 14 itself can be connected by normal soldering, highly reliable torque measurement can be performed. It will be possible.

By the impact torque generated by the impact wrench 1, the shaft 3 and the socket 2 are repeatedly rotated and suddenly stopped, and the bolt 15 is tightened. Here, the sensor case 4 also rotates while the shaft 3 rotates. When the rotating shaft 3 suddenly stops, an impact force is directly transmitted to the socket 2 and the bolt 15, but a spring is interposed between the sensor case 4 and the shaft 3, so that the sensor case The inertial energy of rotation of 4 is gradually absorbed by the spring, and the impact force is not directly transmitted.

Here, the processing section 11 and the display section 12 which are susceptible to vibration and shock are built in the sensor case 4, and the sensor case 4
Is in a state of being floated in the rotational direction with respect to the shaft 3 by a spring, so even if a tool that generates an impact force such as an impact wrench, the impact torque and vibration transmitted to the shaft 3 are blocked by the spring. Is not transmitted to the processing unit 11 and the display unit 12, and the processing unit 1
1. It is possible to prevent the display unit 12 from being damaged.

As the shock absorbing means, in addition to the above constitution,
A spring may be provided between the convex portions 6a, 6b, 6c, 6d of the shaft 3 and the concave portions 7a, 7b, 7c, 7d of the sensor case 4 in the shaft axial direction.

Further, the connection between the strain gauge 13 and the processing portion 11 is within a relative rotation range restricted by the convex portions 6a, 6b, 6c and 6d of the shaft 3 and the concave portions 7a, 7b, 7c and 7d of the sensor case 4. Since the lead wire 13 having a length taken into consideration can be used for normal soldering, it is possible to measure torque with high reliability.

[0017]

As described in detail above, according to the torque detecting device of the present invention, the signal processing unit is provided in the rotating unit via the shock absorbing means, so that the rotating unit such as the strain gauge or the magnetostrictive torque sensor is provided. It is possible to process the detection result obtained by the strain detection unit in the torque detection device without connecting the strain detection unit and the external processing device via a contact type slip ring or a non-contact type rotary transformer. it can. Therefore, even when the rotary tightening tool generates an impact torque, the tightening torque can be measured reliably and accurately without causing noise or disturbance in the transmission of the electric signal.

[Brief description of drawings]

FIG. 1 is a sectional view of a torque measuring device.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view of a torque measuring device using a slip ring.

FIG. 4 is a cross-sectional view of a torque measuring device including a signal processing unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Impact wrench 2, 18 ... Socket 3, 17 ... Shaft 4 ... Sensor case 5 ... Impact absorbing means 6a, 6b, 6c, 6d ... Shaft convex part 7a, 7b, 7c, 7d ... Sensor case concave part 8a, 8b, 8c , 8d ... Spring 9 ... Bearing 10, 26 ... Battery 11 ... Processing part 12 ... Display part 13, 20 ... Strain gauge 14 ... Lead wire 15, 19 ... Bolt 16 ... Rotating tightening tool 21 ... External processing device 22 ... Amplifier part 23 ... Processing part 24 ... Display part 25 ... Slip ring

Claims (1)

[Claims] 1. A strain detection unit for detecting a torsional strain of a rotary unit provided on a rotary unit of a rotary tightening tool, and a signal processing unit integrally provided on the rotary unit via a shock absorbing means. Detection device for rotary tightening tools consisting of parts.