JP3201544B2 - Micro torque measuring instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a small torque of a small motor.

[0002]

2. Description of the Related Art Conventionally, there is a measuring instrument for a minute torque as shown in FIG. This rotating torque measuring device fixes a motor rotating shaft 1 and a pulley 2, winds a thin wire 3 around the pulley 2, and generates a load rotating torque to the motor by utilizing a slip between the pulley 2 and the thin wire 3. In the direction of gravity of the wound fine wire 3, a weight 4
, And a load detector 5 such as a spring weigher is attached upward. As shown in FIG. 2, the load detector 5 is mounted at a certain angle θ, and by changing this angle θ, the load torque to the motor is changed. In a state where the rotation torque is not applied, the load detector 5 indicates the weight of the weight 4. Next, thin line 3
Is attached at an appropriate angle θ, the weight 4 obtains a lifting force. The minute load change is detected by the load detector 5. Further, the load torque and the motor rotation speed are changed by increasing the attachment angle θ of the thin wire 3, and the torque at the time of motor rotation is measured by detecting the load at each rotation speed.

[0003]

In the prior art, since it is relatively easy to change the frictional force acting between the yarn and the pulley to maintain a constant load state, it is used for a relatively large rotary motor. I was However, in this method of measuring motor torque, as the motor itself is reduced in size,
Since the motor torque is also reduced, the motor cannot rotate even with a slight change in the frictional force, making it impossible to detect the torque, and it is difficult to apply a small amount of the frictional force to the motor. There was a problem. Therefore, an object of the present invention is to provide a minute torque measuring device that can measure with high accuracy without variation in measured torque values.

[0004]

To solve the above problems, the present invention provides a torque measuring shaft for mounting a stator of a motor to be measured, bearing means for supporting the torque measuring shaft, and a torque measuring shaft. A load detector that is provided at the shaft end on the non-load side and detects a load based on torque; A rotation sensor for detecting the rotation speed of the measured motor in a non-contact manner ;
Based on the signal of the rotation sensor, the rotation speed of the motor to be measured is
The current of the electromagnetic brake is fed back so as to be constant.
Torque measurement with a control device that controls
A bearing means for supporting the torque measuring shaft,
Non-contact air bearing and the load detector
Weight suspended on the outer circumference of the shaft end of the torque measuring shaft via a thin wire
Are balanced by an electronic balance to detect the load.
I am doing well.

[0005]

According to the above-mentioned means, since the stator side of the motor is mounted on the torque measuring shaft using the air bearing, torque loss due to friction is eliminated, and a minute load can be constantly applied without contact by the electromagnetic brake. Therefore, it is possible to eliminate the variation in the load torque in a minute rotation torque range.

[0006]

FIG. 1 shows a specific embodiment of the present invention. In the figure, reference numeral 6 denotes a motor to be measured,
It comprises a stator 61, a rotor 62 and a motor rotation shaft 63. Reference numeral 7 denotes a torque measuring shaft, 8 denotes an air bearing, and the torque measuring shaft 7 is supported in a non-contact and frictionless state. 9 is an electromagnetic brake, 91 is a disk that generates a load fixed to the shaft end of the motor rotation shaft 63, and 92 is an excitation coil that generates an eddy current in the disk 91 and controls the number of rotations of the motor. Reference numeral 10 denotes a rotation sensor for measuring the number of rotations of the disk 91 in a non-contact manner, and reference numeral 4 denotes a weight, which is suspended by a rod 71 extending from the torque measurement shaft 7 with a thin wire 3. Reference numeral 5 denotes a load detector, which uses an electronic balance, and has a weight 4 before measuring the torque.
And balance. Now, the stator 6 of the motor 6
A voltage is applied to the excitation coil (not shown)
With no load. The coil of the stator 61 is held so as to move freely, and when a torque is generated, a reaction force corresponding to the torque acts on the stator 61. At this time, since the torque measuring shaft 7 to which the motor stator 61 is attached is supported by the non-contact support mechanism of the air bearing 7 without frictional force, the torque is obtained by the reaction force of the rotating torque of the motor 6. . When the stator 61 rotates, the torque measuring shaft 7 connected thereto rotates, the rod 71 rotates, and the weight 4 is lifted in the direction opposite to the direction of gravity. Weight 4
Is lifted, the load of the load detector 5 that has been balanced changes. By multiplying the change in the load by the radius of the rod 71, a torque is obtained. If the rotation speed at this time is read by the rotation sensor 10, the torque at this rotation speed can be measured. Next, when a constant current is applied to the exciting coil 92 of the electromagnetic brake 9 so as to reach the set number of revolutions, a restraining force based on the generation of the eddy current acts on the disk 91, and the number of revolutions of the rotor 62 decreases. Rotation speed. At this time, the torque increases on the stator 61 and a corresponding reaction force acts thereon, so that the load of the load detector 5 also changes accordingly. The torque is obtained from the value of this load in the same manner as described above. If the rotation speed at this time is read by the rotation sensor 10 in the same manner as described above, the torque at that rotation speed can be determined. Hereinafter, by similarly increasing the current of the exciting coil 92 of the electromagnetic brake 9 and measuring the torque at each rotation speed, a rotation speed-torque curve can be obtained. The rotation speed is set by using a control circuit (not shown) by detecting the rotation speed by an externally mounted rotation sensor 11 and feeding back a current value to be supplied to the electromagnetic brake 10 so that the rotation speed can be set to an arbitrary rotation speed. Thus, a constant rotation speed is controlled.
It was found that the rotation speed-torque curve obtained in this way had significantly reduced variation, good reproducibility, and high accuracy as compared with the conventional method. Further 1500 rpm
It has been found that a small torque is detected even in a high-speed region of m or more.

[0007]

As described above, according to the present invention, the electromagnetic brake is used to brake in a non-contact manner, and the air bearing is used to eliminate the loss due to friction. Therefore, there is an effect that it is possible to provide a torque detector that can accurately measure the torque, and thus can detect the minute torque with high accuracy.

[Brief description of the drawings]

FIG. 1 is a sectional view of a minute torque measuring device of the present invention.

FIG. 2 is a sectional view of a conventional torque measuring device.

[Explanation of symbols]

Reference Signs List 1 motor rotating shaft 7 torque measuring shaft 2 pulley 8 air bearing 3 thin wire 9 electromagnetic brake 4 weight 91 disk 5 load detector 92 exciting coil 6 motor 10 rotation sensor 61 motor stator 62 motor rotor 63 motor rotating shaft

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-153440 (JP, A) JP-A-52-132888 (JP, A) JP-A-55-36778 (JP, A) 76632 (JP, U) Japanese Utility Model Showa 64-30664 (JP, U) Japanese Utility Model Showa 60-66269 (JP, U) Japanese Utility Model Showa 62-201033 (JP, U) Japanese Patent Publication No. 48-31271 (JP, B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01L 5/00

Claims (1)

(57) [Claims] 1. A torque measuring shaft for mounting a stator of a motor to be measured, bearing means for supporting the torque measuring shaft, and a load for detecting a load based on torque provided at a shaft end on a non-load side of the torque measuring shaft. A detector, an electromagnetic brake comprising a disk fixed to the shaft end of the motor to be measured and an exciting coil provided in a non-contact manner on both surfaces of the disk, and a non-contact rotation speed of the motor to be measured. A rotation sensor for detecting ,
Based on the signal of the rotation sensor, the rotation speed of the motor to be measured is
The current of the electromagnetic brake is fed back so as to be constant.
Torque measurement with a control device that controls
The bearing means for supporting the torque measuring shaft is provided in a non-contact manner.
Air load, and the load detector measures the torque
The weight suspended on the outer periphery of the shaft end via a fine wire is
And load detection.
Small torque measuring instrument.