JPH1177555A - Torque wrench - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and accurately measure fastening torque. SOLUTION: This torque wrench 11 comprises: a socket 13 to be fitted to the head part of a bolt 12; a socket holding part 14 holding the socket 13; an operation part 15 extended in the radial direction from the socket holding part 14, and a revolving angle detection part 16 provided at the upper part of the socket holding part 14. A ratchet mechanism 17 revolvable only in one direction is provided in the inside of the socket holding part 14. The revolving angle detection part 16 comprises an angle sensor 21, a servomotor 22, and of an azimuth sensor 23 detecting the direction of a magnetic line acting as a reference. The revolving angle of the socket 13 detected by the angle sensor 21 is determined based on a difference in position from a reference position detected by the azimuth sensor 23. Therefore, when the operation part 15 is operated so as to be revolved and the socket 13 is revolved stepwise in the tightening direction, tightening torque can be detected based on a difference in position from a reference position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque wrench, and more particularly, to a torque wrench configured to accurately measure a tightening torque by using a torque gradient method.

[0002]

2. Description of the Related Art Conventional torque wrenches include a protractor system, an encoder system, and a gyro system when classified according to a method of detecting a tightening angle. First, in the protractor method, a fixing tool extended from a disc-shaped protractor is fixed, and a tightening torque is applied to a socket engaged with a head of a bolt by a rotating operation of an operation unit extending in a radial direction. It has a configuration. Then, the turning angle of the bolt is detected from the turning position of the pointer extending on the protractor.

[0003] In the encoder system, for example, as shown in Japanese Utility Model Application Laid-Open No. 4-63361, a tightening torque is applied to a socket engaged with a head of a bolt by a turning operation of an operating portion extending in a radial direction. Then, a signal proportional to the turning angle of the socket is obtained by a rotary encoder built in the socket holding unit for holding the socket, and the turning angle of the bolt is displayed from this signal. Also in this method, it is necessary to fix the socket holding portion with a fixture.

In the gyro system, a gyro is provided inside a socket holding portion to detect a magnitude of a tightening torque as disclosed in, for example, Japanese Patent Application Laid-Open No. 8-197445. In the gyro, a triangular prism-shaped piezoelectric vibrator is erected, and a piezoelectric element for excitation and two
And a plurality of detection piezoelectric elements. When the operation unit is rotated, an output corresponding to the rotational angular velocity is generated from the detecting piezoelectric element. Therefore, the magnitude of the tightening torque is detected based on a change in the output of the detecting piezoelectric element.

[0005]

However, in the conventional torque wrench having the above-mentioned structure, it is necessary to fix the torque wrench with a fixing tool. Therefore, when tightening a large number of bolts, for example, when tightening a cylinder head of an engine, it is necessary to fix the fixture to the cylinder head before tightening each bolt. , It was difficult to increase work efficiency.

Further, in the gyro-type torque wrench, since the rotational angle is obtained by integrating the rotational angular velocity, an error occurs in the calculation process, and there is a possibility that the accuracy of detecting the tightening torque is reduced. Therefore, an object of the present invention is to provide a torque wrench that solves the above problems.

[0007]

In order to solve the above problems, the present invention has the following features. The present invention provides a socket engaged with a screw member, an operation unit for rotating the socket, a rotation angle detection unit for detecting a relative rotation angle between the operation unit and the socket, In a torque wrench having a torque detecting unit for detecting an applied torque, the rotation angle detecting unit includes a magnetic detecting unit for detecting a direction of a magnetic field line serving as a reference, and the socket relative to a reference position detected by the magnetic detecting unit. An angle detection unit for detecting a rotation angle of the motor, and a motor for rotating the magnetic detection unit based on the rotation angle of the socket detected by the angle detection unit such that the magnetic detection unit maintains a reference position. And characterized by the following.

Therefore, according to the present invention, the rotation angle of the socket is detected by using the position detected by the magnetic detection unit, which detects the direction of the magnetic line of force as a reference, as the reference position, and the magnetic detection unit determines the reference position. Since the magnetic detection unit is rotated so as to be maintained, it is not necessary to perform the operation of fixing using the fixing device as in the related art, and the work efficiency of the tightening operation can be increased by that amount. Further, since the rotation angle of the socket can be directly detected, the detection accuracy of the tightening torque can be improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of an embodiment of the torque wrench according to the present invention. FIG. 2 is a longitudinal sectional view showing an assembled state of the torque wrench. As shown in FIGS. 1 and 2, the torque wrench 11 includes a socket 13 fitted to a head of a bolt 12, a socket holding portion 14 for holding the socket 13, and a radial extension from the socket holding portion 14. And a rotation angle detector 16 provided above the socket holder 14. Also,
The torque wrench 11 is configured to obtain a bolt tightening angle by using a torque gradient method of simultaneously tightening up to a specified value obtained from the relationship while simultaneously measuring a rotation angle and a torque corresponding to the angle.

A ratchet mechanism 17 rotatable in only one direction is provided inside the socket holding portion 14. The ratchet mechanism 17 is connected to the socket holder 14.
And a ratchet wheel 19 rotatably provided inside the socket holding portion 14. The ratchet claw 18 is formed in an L-shape when viewed from above, as indicated by a broken line in FIG. 1. Switch to the direction or counterclockwise. When the operation unit 15 is rotated and the bolt 12 is tightened, the ratchet pawl 18
Drives the engaging ratchet wheel 19 in the rotation direction to rotate the socket 13 in the same direction.

The upper surface of the socket 13 is formed in a rectangular recess 13a. On the lower surface of the ratchet wheel 19, a rectangular projection 19a that fits into the recess 13a protrudes. The rotation angle detection unit 16 includes an angle sensor 21, a servo motor 22 provided above the angle sensor 21, and an azimuth sensor (magnetic detection unit) 23. The angle sensor 21 has an optical encoder 21a fixed to the upper surface of the ratchet wheel 19, and a rotating body 21b provided rotatably with respect to the optical encoder 21a. Therefore, the optical encoder 21a
Outputs a signal corresponding to the amount of rotation of the ratchet wheel 19 by relative rotation with the rotating body 21b.

The azimuth sensor 23 is composed of an electronic attitude sensor for detecting the direction of a magnetic field line as a reference, and is composed of, for example, an electronic compass or an inclinometer. In this embodiment, north is set as a reference position as an azimuth in which geomagnetism can be detected. Further, a magnetic compass may be used as the direction sensor 23. This magnetic compass can detect the direction of the torque wrench 11 by arranging two bar magnets on a card supported by a pivot bearing and determining the horizontal component direction of the earth's magnetic field. The periphery of the rotation angle detection unit 16 is covered with a cover 24 fixed to the upper surface of the socket holding unit 14.

The servomotor 22 is a geared motor having a built-in reduction gear, and the shafts 22a and 22b of the rotor project vertically. The shaft 22a projecting upward is
The direction sensor 23 is coupled to the substrate. Further, the shaft 22 b protruding downward is connected to the rotating body 21 b of the angle sensor 21. Therefore, when the ratchet wheel 19 and the socket 13 are turned by the turning operation of the operation unit 15, the load of the servomotor 22 causes the optical encoder 21 a and the rotating body 21 b to rotate relatively. Therefore, the encoder 21a of the angle sensor 21
Is a ratchet wheel 1 associated with a rotation operation of the operation unit 15.
9 and the rotation angle α of the socket 13 can be detected.

Then, the direction of the torque wrench 11 is set to an angle β with respect to the north direction as a reference position by the direction sensor 23.
When the servomotor 22 detects that the azimuth sensor 23 has just rotated clockwise, the servo motor 22 rotates the direction sensor 23 counterclockwise by the angle β. Thereby, the direction sensor 23 is always maintained at a position where a fixed direction (north direction) can be detected. FIG.
FIG. 2 is a circuit diagram for controlling driving of a motor.

A signal a corresponding to the rotation angle with respect to the reference position (north direction) detected by the direction sensor 23 based on the geomagnetism is in accordance with the rotation angle α of the ratchet wheel 19 and the socket 13 detected by the angle sensor 21. Signal b
, Is amplified by the amplifier 25 and supplied to the servomotor 22. Therefore, the servo motor 22 always returns the direction sensor 23 by an angle equal to the rotation angle of the torque wrench 11. Therefore, the azimuth sensor 23 always detects a fixed azimuth (north azimuth) and adjusts the direction so that the rotation angle with respect to the reference position (north) becomes zero.

The rotation angle α of the socket 13 detected by the angle sensor 21 is obtained from the difference from the reference position detected by the direction sensor 23. Therefore, the operation unit 1
When the socket 5 is rotated to rotate the socket 13 in the tightening direction, the tightening torque is detected from the difference from the reference position. Then, when the preset tightening torque is reached, a display is provided on the cover 24 to notify the operator that the tightening torque of the bolt 12 is sufficient.

As described above, since the azimuth sensor 23 for detecting the direction of the magnetic line of force serving as a reference is built in the rotation angle detecting section 16, it is not necessary to fix it using a fixing device as in the prior art. . Therefore, socket 13 is simply bolt 1
2, the bolt 12 can be tightened with a predetermined tightening torque only by rotating the operation unit 15.

Therefore, the bolt 12 can be tightened with higher working efficiency than the conventional one, and the tightening torque can be accurately detected. In the above embodiment, the case where the bolt 12 is tightened has been described as an example. However, a nut other than the bolt 12 or a hexagonal or square screw member may of course be tightened.

In the above-described embodiment, the azimuth sensor 23 has been described as detecting the geomagnetic direction (north).
However, the present invention is not limited to this. For example, it is also possible to detect the direction of the line of magnetic force from a clamped body such as a cylinder head or a magnet adsorbed in the vicinity thereof.

[0020]

As described above, according to the present invention, the angle detecting section detects the rotation angle of the socket with the position detected by the magnetic detecting section for detecting the direction of the magnetic field line as a reference as the reference position, and the magnetic detecting section. However, since the magnetic detection unit is rotated so as to maintain the reference position, it is not necessary to perform the operation of fixing using the fixing device as in the related art, and the work efficiency of the tightening operation can be increased by that amount. Further, since the rotation angle of the socket can be directly detected, the detection accuracy of the tightening torque can be improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an embodiment of a torque wrench according to the present invention.

FIG. 2 is a longitudinal sectional view showing an assembled state of the torque wrench.

FIG. 3 is a circuit diagram for controlling driving of a motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Torque wrench 13 Socket 14 Socket holding part 15 Operation part 16 Rotation angle detection part 17 Ratchet mechanism 18 Ratchet claw 19 Ratchet wheel 21 Angle sensor 22 Servo motor 23 Direction sensor 24 Cover

Claims (1)

[Claims] A socket engaged with a screw member; an operation unit for rotating the socket; a rotation angle detection unit for detecting a relative rotation angle between the operation unit and the socket; A torque wrench having a torque detector that detects a torque applied to the wrench; the rotation angle detector is a magnetic detector that detects a direction of a magnetic line of force that is a reference; An angle detection unit that detects a rotation angle of the socket; and the magnetic detection unit is rotated based on the rotation angle of the socket detected by the angle detection unit such that the magnetic detection unit maintains a reference position. A torque wrench comprising: a motor;