JPH04370776A - Torque characteristic measuring method for stepping motor - Google Patents

Abstract

PURPOSE:To facilitate the measurement of a holding torque and a detent torque. CONSTITUTION:Two ends of yarn wound on a pulley 2 connected to a shaft of a stepping motor 1 to be measured are connected to two torque sensors 3a and 3b. The two torque sensors 3a and 3b are moved in the same direction in synchronization with each other along the direction of the yarn starting from the rest of the yarn and thus, a holding torque and a detent torque of the stepping motor 1 are measured from a difference between output values of the two torque sensors 3a and 3b during the movement thereof.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the torque characteristics of stepping motors, and more particularly to a method for measuring holding torque and detent torque.

0002

[Background Art] In recent years, stepping motors have been widely used for control purposes in a wide range of industrial fields, and knowing their characteristics is important in order to use these motors in optimal conditions and with high performance. It is. FIG. 6 shows an example of a conventional measurement method, in which a rotary encoder 62, a torque sensor 63, and an external displacement stepping motor 64 are connected to the rotating shaft of a motor 61 to be measured by a coupling 65 as shown in the figure. There is.

FIG. 7 shows another conventional example of torque measurement, in which both ends of a thread 74 wound around a pulley 72 of a motor 71 to be measured are held by torque sensors 73a and 73b, respectively. Torque sensors 73a and 73b are arranged on fixed head 75 and guide rail 76, respectively. The torque sensor 73b is movable on the guide rail 76 by screwing together a rotating shaft 78 rotatably driven by a stepping motor 77 for varying the load and moving the head, and a support head 79 thereof. Here, by driving the stepping motor 77 for varying the load and for moving the head, the torque sensor 73b
By moving on the guide rail 76, the tension on the thread 74 changes, and the load applied to the motor 71 to be measured can be changed. In the measurement method shown in Fig. 7, the torque/frequency (
τ-f) characteristics can be measured.

0004

[Problem to be Solved by the Invention] Among the torque characteristics of a stepping motor, when a torque is applied from the outside to the output shaft while the motor is energized and stationary, the maximum torque that is generated to counteract this is when the motor is stationary. Torque (holding torque), and residual torque (detent torque) is the maximum torque generated to counteract external torque applied to the output shaft when the motor is stationary without excitation. . In the conventional method described above, it is not possible to obtain such holding torque and detent torque.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for measuring the torque characteristics of a stepping motor that can easily measure holding torque and detent torque.

[0006]

[Means for Solving the Problems] In order to achieve this object, the method for measuring torque characteristics of a stepping motor according to the present invention is such that both ends of a thread wound around a pulley coupled to the shaft of a stepping motor to be measured are Connected to a torque sensor, the two torque sensors are synchronized and moved in the same direction along the direction of the thread from a state where the thread is stationary, and the difference between the output values of the two torque sensors during the movement is determined. The holding torque and detent torque of the stepping motor are measured.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which 1 is a motor to be measured, 2 is a pulley thereof, 3a and 3b are torque sensors such as strain gauge type, and 4 is a motor wound around the pulley 2 once or twice. 5a and 5b are guide rails that movably support the torque sensors 3a and 3b, 6a and 6b are stepping motors for variable load, and 7a and 7b are stepping motors for variable load. Rotating shafts of motors 6a, 6b, 8a, 8b are guide rails 5a
, 5b in a movable state, respectively, and rotation shafts 7a, 7b.
The support head is screwed into each of the support heads to control movement along its axis. 9 is an installation stand for the motor to be measured 1;
It is mounted on a base 10 so that guide rails 5a and 5b are positioned on both sides of the installation base 9. 11a,
11b and 11c use the power supplied from the power supply 12 to
A driver drives the motor 1 to be measured and the load variable stepping motors 6a and 6b according to control signals such as frequency commands from U13, and 14a and 14b are torque sensors 3a.
, 3b as inputs,
These outputs are input to a differential amplifier (differential AMP) 15. The output of the differential amplifier 15 is processed by the CPU 13 as a torque value of the motor 1 to be measured.

The measurement method of the present invention using the configuration shown in FIG. 1 will be explained. FIG. 2 is a configuration diagram showing the main parts. (2) Drive the variable load stepping motors 6a and 6b to tension the thread 4 wound around the pulley 2. Guide rail 5
The movements of a and 5b are in opposite directions in the direction in which the thread 4 is stretched, and the torques acting on the thread 4 are the same amount t0 but in opposite directions. The torque applied to the shaft of the stepping motor 1 to be measured only needs to be equal to or greater than the holding torque value,
For example, it is set to about twice the holding torque value. ■ In this state, the pulley 2 of the motor 1 to be measured is made to stand still. In the densest case, the torque value does not necessarily become zero at this time. (2) Using this stationary state as a starting point, the load variable stepping motors 6a, 6b are driven in synchronization, so that the guide rails 5a, 5b are synchronized and moved by the same amount in the same direction. (2) The pulley 2 of the stepping motor 1 to be measured rotates according to the movement of the guide rails 5a and 5b, that is, the movement of the thread 4. Here, when the table movement amount is d and the radius of the pulley is r, the rotation θ of the pulley 2 is θ=d/r. ■ The torque t applied to the pulley 2, that is, the torque generated in the stepping motor 1 to be measured, is measured by the torque sensors 3a and 3b.
, 3b are respectively t1 and t2, t=t1-t2. This difference is obtained at the output of the differential AMP 15. Therefore, without measuring the rotation angle θ, the torque (t)
can be measured. This torque t is the torque generated when torque is applied from the outside to the shaft of the stepping motor 1 to be measured, and if the direction of the external force is positive when it is clockwise, then the motor shaft The direction of the torque is counterclockwise when the torque value is positive, and clockwise when the torque value is negative. FIG. 3 shows the characteristics of torque (t) with respect to the amount of movement (d) of the guide rail. ■ In the above example, the maximum value of torque (t) measured while stationary with no excitation is the detent torque (residual torque), and the maximum value of the value measured while stationary with rated excitation is the holding torque. (Maximum static torque)
It is. Detent torque appears in stepping motors that use permanent magnets in their rotors.

FIG. 4 shows the number of steps (PS) of the stepping motor for varying the load, which corresponds to the amount of movement of the guide rail, from 0 to 4.
It shows actual measured values of torque (t) characteristics for 00. FIG. 5 shows actual measured values of the characteristics of the torque number (t) with respect to the step number (PS) of the load variable stepping motor from 0 to 2000, which corresponds to the amount of movement of the guide rail.

0010

As described in detail above, according to the present invention, it is possible to simultaneously measure torque while externally applying rotation to the shaft of the stepping motor to be measured, and to easily measure detent torque and holding torque. Since it is possible to measure the amount of time, it is extremely effective when applied to product management, etc. in the manufacturing process of stepping motors.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram for explaining an embodiment of the present invention.

FIG. 2 is a configuration diagram for explaining main parts of an embodiment of the present invention.

FIG. 3 is a diagram for explaining measurement characteristics by the measurement method of the present invention.

FIG. 4 is a characteristic diagram showing an example of actual measurement using the measurement method of the present invention.

FIG. 5 is a characteristic diagram showing an example of actual measurement using the measurement method of the present invention.

FIG. 6 is a configuration diagram for explaining a conventional torque characteristic measuring method.

FIG. 7 is a configuration diagram for explaining a conventional torque characteristic measuring method.

[Explanation of symbols]

1, 61, 71 Stepping motor to be measured 2, 72
Pulleys 3a, 3b, 62, 63, 73a, 73b Torque sensors 4, 74 Threads 5a, 5b, 76 Guide rails 6a, 6b Load variable stepping motors 7a, 7
b, 78 Rotating shafts 8a, 8b, 79 Support head 9 Installation stand 10 Base 11a, 11b, 11c Driver 12 Power supply 13 CPU 14a, 14b Amplifier (AMP) 15 Differential amplifier (differential AMP) 62 Rotary encoder 64 External displacement Stepping motor 65 Coupling 75 Fixed head

Claims (1)

[Claims] Claim 1: Both ends of a thread wound around a pulley connected to the shaft of a stepping motor to be measured are connected to two torque sensors, and when the thread is stationary, the two torque sensors are synchronized to detect the thread. A method for measuring torque characteristics of a stepping motor, comprising moving the stepping motor in the same direction along the same direction, and measuring a holding torque and a detent torque of the stepping motor from the difference in output values of the two torque sensors during the movement.