JPH11132876A - Torque-measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a torque accurately even when a rotational speed is low with a rotational load set on a rotary shaft of a rotary mechanism, by calculating a torque generated by the rotary mechanism on the basis of an acceleration detected by an accelerometer. SOLUTION: A motor load 1 is set at a leading end part of a rotary shaft (conduction shaft) 102 of a rotary mechanism 101 of a motor or the like of a torque generation source (sample) generating a torque to be measured. An accelerometer 2 is fixed to the motor load 1 and provided with a chopper to modulate, AC couple and take out acceleration signals correctly. The accelerometer 2 is mounted at a position of a radius γ from the center of a rotary shaft 102. A detection shaft A of the accelerometer 2 is fixed in a direction orthogonal to a radial direction of the rotary shaft 102 and motor load 1. A data-processing apparatus 5 is connected to a rotary transformer 3 and calculates a torque generated from the rotary mechanism 101 on the basis of an angular acceleration obtained by the accelerometer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque measuring device, and more particularly to a torque measuring device capable of measuring a torque even when a rotating load is attached to a rotating shaft and the rotating speed of the rotating shaft is low.

[0002]

2. Description of the Related Art FIG. 2 is a perspective view of a conventional torque measuring device. As shown in FIG. 2, a rotation speed control brake 103 is attached to a tip end side of a rotation shaft (conduction shaft) 102 of a rotation mechanism 101 composed of a motor or the like.
A torque meter (torsion dynamometer) 104 having a strain gauge is attached to an intermediate portion of the reference numeral 02. Then, the brake is applied under the condition that the rotating shaft 102 is rotating at a constant speed, and the torque of the rotating mechanism 101 when the torque generated by the rotating mechanism 101 and the torque generated by the brake 103 are balanced is directly changed. Measured.

FIG. 3 is a perspective view of another conventional torque measuring device. As shown in FIG. 3, a motor load 105 is fixed to the tip of the rotating shaft 102 of the rotating mechanism 101, and a tachometer 106 is attached to an intermediate portion of the rotating shaft 102. In measuring the torque of the rotation mechanism 101, first, the rotation speed of the rotation shaft 102 is detected by the tachometer 106. Next, in the data processing device 107, an angular acceleration is calculated from the temporal change of the detected rotation speed, and further, a torque generated in the rotation mechanism 101 is indirectly obtained by calculation based on the angular acceleration.

[0004]

However, in the case of the conventional example shown in FIG. 2, when the rotary load is attached to the rotary shaft 102 (for example, the state shown in FIG. 3), the rotation mechanism 101 is generated. The disadvantage is that the torque cannot be measured. That is, the measuring method shown in FIG. 2 cannot be applied to a general assembled product.

In the case of the conventional example shown in FIG. 3, the torque generated by the rotating mechanism 101 in a state where the rotating load 105 is mounted (ie, a general assembled product) can be measured. When the speed is low, the output of the tachometer 106 decreases. As a result, when calculating the angular acceleration from the temporal change of the rotation speed, there is a disadvantage that the measurement error increases and the measurement accuracy deteriorates.

Accordingly, an object of the present invention is to provide a torque measuring device capable of accurately measuring torque even when a rotating load is attached to a rotating shaft of a rotating mechanism and the rotating speed is low. It is to be.

[0007]

In order to solve the above-mentioned problems, according to the invention described in the claims, an accelerometer is mounted in the direction of the radius of rotation of a rotating load fixed to a rotating shaft for transmitting a torque generated by a rotating mechanism. The torque calculating means calculates a torque generated by the rotating mechanism based on the acceleration detected by the accelerometer. In this way, it is possible to directly measure the torque generated by the rotating mechanism while the rotating load is attached (in a state where the product is assembled into a product).

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. FIG. 1 is a perspective view showing the embodiment.

As shown in FIG. 1, a rotating mechanism 1 composed of a motor or the like which is a source (sample) of a generated torque to be measured.
The motor load (rotational load) 1 is attached to the tip of the rotation shaft (conduction shaft) 102 of the motor. An accelerometer 2 is fixed to the motor load 1, and the accelerometer 2 is provided with a chopper (not shown) for modulating an acceleration signal to perform AC coupling and accurately extract the signal. Accelerometer 2
Is mounted at a position of a radius r from the center of the rotating shaft 102, and the detection axis A of the accelerometer 2 is fixed to be orthogonal to the rotating shaft 102 and the radial direction of the motor load 1.
When the detection axes are fixed orthogonally as described above, each acceleration is converted into an acceleration, so that the acceleration can be detected efficiently and accurately. Although the shape of the motor load 1 is shown as a thick disk, it is not limited to the disk, and the load shape of an actual product (an assembled product) may be used as it is. As the accelerometer 2, a highly sensitive type such as a gyro-type accelerometer or a piezoelectric accelerometer is suitable.

A rotary transformer 3 having a rotating part and a fixed part is attached to the center of the rotating shaft 102, and the accelerometer 2 is connected to the rotary transformer 3 via a signal line 4. The rotary transformer 3 is a signal transmission transformer for taking out the output of the accelerometer 2 that rotates simultaneously with the motor load 1 to the outside (a type used for a VTR or the like is preferable).

A data processing device 5 is connected to the rotary transformer 3, and the data processing device 5 calculates a torque generated by the rotation mechanism 101 based on the angular acceleration obtained from the accelerometer 2. Next, the operation of this embodiment will be described. The rotation of the rotation mechanism 101 causes the rotation shaft 102 to rotate.
And the motor load 1 is rotated, and the accelerometer 2 detects the acceleration α by the following equation (1). α = [dω / dt] × r (1) where, dω / dt: angular acceleration of the rotary load 1 r: mounting position of the accelerometer with respect to the rotation axis

In the data processing device 5, the angular acceleration of the rotary load 1 is obtained from the following equation (2) from the acceleration α obtained from the above equation (1). dω / dt = α / r (2) Similarly, in the data processing device 5, the torque T generated in the rotating mechanism 101 from the angular acceleration obtained by the above equation (2) is obtained by the following equation (3). T = I × [dω / dt] = I × α / r (3) where I is an inertia coefficient of the rotational load 1 of the rotating mechanism 101, and is a value of the rotational load including the rotational load 1 and the accelerometer 2. It is an inertia performance rate.

As is apparent from the above equation (2), in the present invention, since the angular acceleration is directly obtained based on the acceleration α detected by the accelerometer 2 and the mounting position r, when the rotational speed becomes low, However, the torque can be accurately obtained.
The torque T can be obtained as described above. Then, for example, a display device (not shown) may be provided in the data processing device 5 to display the obtained torque T.

[0014]

As described above, according to the present invention, an accelerometer is attached to a rotating load, and the torque is calculated based on the acceleration detected by the accelerometer. (In assembled state)
The torque can be measured accurately.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a perspective view of a conventional example.

FIG. 3 is a perspective view of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor load (rotational load) 2 Accelerometer 3 Rotary transformer 4 Signal line 5 Data processor 101 Rotary mechanism 102 Rotary axis

Claims (3)

[Claims] 1. An accelerometer is attached to a rotating shaft, which transmits a torque generated by a rotating mechanism, in a direction of a radius of rotation of a rotating load fixed to a rotating shaft. A torque measuring device, wherein the torque is calculated by a torque calculating means. 2. The torque measuring device according to claim 1, wherein the accelerometer has a detection axis mounted orthogonal to a radial direction of the rotation axis and a rotation load. 3. The torque measuring device according to claim 1, wherein a rotary transformer is attached to the rotating shaft, and an output signal of the accelerometer is transmitted to the torque calculating means via the rotary transformer. apparatus.