JPH11118470A - Information of shaft position detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the measurement precision of the rotating angle, angle speed and angle acceleration of a micro motor of milli-machine or less by providing the intrinsic circumferential direction signal of a rotating shaft on the basis of the signal information continuously outputted in real time from a non-contact displacement sensor, and recognizing the rotating angle, angle speed and angle acceleration. SOLUTION: A non-contact displacement sensor continuously detect the circumferential direction displacement of a rotating shaft which is rotated, or the surface form or minute roughness in real time, and provides a waveform signal in which the displacement is fluctuated to time. The positions (a)-(k) on the circumference of the rotating shaft corresponding to waveform signals (a)-(k). Since the angle aox is univocally determined in relation to the position on the optional circumference of the rotating shaft, the rotating angle of the rotating shaft in an optional time can be continuously recognized from the phase and displacement to the origin of the displacement waveform signal. Further, the time-rotating angle relational expression can be calculated on the basis of this waveform signal, this relational expression can be differentially calculated to calculate the time-angle speed relational expression, and the time-angle acceleration relational expression can be further calculated by the differential calculation thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation angle, (angular) speed and (angular) acceleration detecting means of a small motor of millimeter machine or less.

[0002]

2. Description of the Related Art Conventionally, a hall element utilizing a Hall effect and a resolver utilizing a change in impedance between a stator and a rotating body having salient poles connected to a rotating shaft are incorporated in a stator of a motor. It is used as a motor rotation angle detector.

[0003] A tachometer which is directly connected to a rotating shaft and generates a voltage proportional to the rotation speed, or a device utilizing an induced voltage generated in an armature winding of a motor is used as a speed detector.

[0004] When a rotating disk, which is attached to a rotating shaft and has slits arranged at predetermined intervals in the circumferential direction, rotates, the slits interrupt the light path of a sensor section comprising a light emitting element and a light receiving element. An optical rotary encoder which is cut off from the sensor and outputs a rectangular wave signal indicating a rotation angle and a speed from a sensor unit is used as a rotation angle and a speed detector.

As described above, the conventional rotation angle / speed detector is generally used inside a motor or mounted on a rotation shaft.

[0006]

However, for example, when measuring the rotation angle and the speed of a small motor of a millimeter machine or less with respect to time, if the detector is directly connected to the rotation shaft of the motor to be measured, as in the prior art. Since the moment of inertia of the rotor of the detector is large or not negligible compared to the moment of inertia of the rotor of the motor, the effect of the detector on the measured value is large and the characteristics of the motor to be measured cannot be measured accurately. Had the disadvantage that

Connecting the detector to the rotating shaft of the motor to be measured also means that a load is connected, and the motor to be measured is operated with an unnecessary load applied during measurement. Disadvantage.

The influence of the detector as described above becomes more conspicuous as the size of the motor to be measured becomes smaller, and has become a major obstacle in measuring the rotation angle or speed of the motor itself. On the other hand, with the downsizing of the motor, the extra space inside the motor has been reduced, and it is very difficult to incorporate a sensor such as a Hall element.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks, eliminate the influence of a detector when measuring the rotation angle, speed or acceleration of a small motor of millimeter or less, and greatly improve the measurement accuracy. It is intended for.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and the invention according to the first aspect is directed to a method of forming a surface shape of a rotating shaft in a circumferential direction and information on minute roughness thereof. Based on the signal information from the non-contact type displacement sensor that outputs continuously in real time, obtains the circumferential direction signal unique to the rotation axis and recognizes the rotation angle, speed and acceleration including the starting point of the rotation axis Is what you do.

[0011]

[Function] Since the detector does not contact the motor to be measured, even if the motor to be measured is a small motor of a millimeter machine or smaller, the influence of the detector at the time of measurement can be eliminated, and the measurement accuracy is greatly improved. realizable.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a diagram illustrating a shaft position information detecting device according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating a shaft position information detecting device according to another embodiment of the present invention.

The measuring system and the detecting means which are the gist of the present invention will be described with reference to FIG. 1. As shown in FIG. 1 (a), the measuring system of the present invention comprises, for example, a laser displacement meter, a capacitance type displacement. Non-contact type displacement sensors such as
It is composed of an arithmetic unit for recognizing the cycle or pulse width of the displacement output signal from the sensor and performing various calculations.

In the non-contact type displacement sensor, as shown in FIGS. 1A and 1B, the circumferential displacement of the rotating rotating shaft, that is, the surface shape and minute roughness are continuously and continuously measured in real time. For example, the cross section of the detected part of the rotating shaft is
In the case of the shape shown in FIG. 1, a non-contact displacement sensor obtains a waveform signal in which the starting point is time = 0 and the displacement varies with time, as shown in FIG.

Here, positions a to k on the circumference of the rotating shaft shown in FIG. 1B correspond to a to k shown in FIG. In the figure, point a indicates the starting point, point p indicates the stopping point, and point o indicates the axis center.

In FIG. 1B, since the angle ∠aox is a value uniquely determined with respect to an arbitrary circumferential position x of the rotating shaft, the displacement waveform signal output from the non-contact displacement sensor is From the phase with respect to the starting point and its displacement, the rotation angle of the rotating shaft at any time can be continuously recognized.

For example, in the case of FIG. 1C, the rotation axis is set at 2.
It can be seen that the motor stopped after 20 rotations (rotation angle = 13.8 rad = 793.0 °). Furthermore, the angular velocity at an arbitrary time can be recognized by dividing the rotation angle change between two points by the time change.

Another detecting means will be described below. Based on the signal output from the non-contact type displacement sensor,
Calculate the rotation angle relational expression. Subsequently, the time-rotation angle relational expression is differentiated to calculate a time-angular velocity relational expression.
Further, the time-angular velocity relational expression is differentiated to calculate the time-
Calculate the angular acceleration relational expression. By the above-described arithmetic processing, the rotation angle, the angular velocity, and the angular acceleration at an arbitrary time can be recognized.

The above-described surface shape and minute roughness on the circumference of the rotating shaft are unique to the rotating shaft, which vary depending on the variation of the outer diameter and roundness, the processing method, and the state of the surface finish, and can be said to be the axial fingerprint. Things. Therefore, the present invention can also be used for identifying a rotation axis.

In the case where the rotation of the rotating shaft is displaced during rotation and the recognition of the rotation angle is hindered, an HPF (High Pass Filter) for blocking a frequency component lower than the rotation speed is provided with a non-contact type displacement sensor and an arithmetic unit. The problem can be solved by inserting between them. In addition, the present invention, such as forming a groove in the rotating shaft,
There is no problem even if the processing for positively characterizing the surface shape is performed.

For example, FIG. 2A is a sectional view of a portion to be detected of the rotating shaft.
In the case of processing into the shape shown in (1), the non-contact type displacement sensor obtains a waveform signal in which the starting point is time = 0 and the displacement varies with time, as shown in FIG. Fig. 2 (a)
2 correspond to the positions a ′ to l ′ on the circumference of the rotation shaft shown in FIG. Point o indicates the axis center.

As described above, since the rotation angle is uniquely determined with respect to an arbitrary position on the circumference of the rotation axis, the phase of the displacement waveform signal output from the non-contact type displacement sensor with respect to the starting point and the displacement thereof can be calculated. , The rotation angle of the rotation shaft at any time can be continuously recognized.

The processing shape of the rotating shaft is not limited to this example, but can be set as appropriate.

[0024]

According to the shaft position information detecting device according to the first aspect of the present invention, as described in detail in the embodiment, the detector for measuring the rotation angle, speed or acceleration of a small motor of millimeter machine or less is used. The influence can be eliminated and the measurement accuracy can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a shaft position information detecting device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a shaft position information detecting device according to another embodiment of the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kakuo Yoshinari 3-8-22 Nitta, Adachi-ku, Tokyo Inside Namiki Seimitsu Jewelry Co., Ltd. (72) Inventor Tetsuo Sekiya 3-8 Nitta, Adachi-ku, Tokyo No. 22 Namiki Seiki Inside Jewelry Co., Ltd.

Claims (2)

[Claims] 1. A circumferential signal unique to a rotating shaft, based on signal information from a non-contact type displacement sensor that continuously outputs, in real time, information on a circumferential surface shape of the rotating shaft and minute roughness information thereof. A rotation angle, a speed, and an acceleration of the rotation axis including the starting point of the rotation axis are recognized. 2. The shaft position information detecting device according to claim 1, wherein at least a portion to be detected of the rotating shaft has a surface shape so as to obtain output waveform information from the non-contact type displacement sensor. A shaft position information detecting device for a rotating shaft, characterized in that it has irregularities.