JPH0357901A - Apparatus for measuring eccentricity of stator of overhung motor - Google Patents

Abstract

PURPOSE:To obtain an apparatus capable of measuring eccentricity of a stator easily with good sensitivity in a short time without contact in the stator by a method whereby a value of eccentricity is detected from the change of inductance generated in the gap between an eccentric center at an inner periphery of a stator core and a sensor. CONSTITUTION:An overhung motor 3 is coupled to a driven body 1 having a rotary shaft 2. A stator core 4 wound with a coil 5 is mounted in the motor 3, and a rotor 6 is fitted into the rotary shaft 2 inside the stator core 4. The coil 5 is wound in a coil groove 7 formed in the stator 4 of the motor 3. A stator tooth 8 is formed between the coils. Before the rotor 6 is fitted in the rotary shaft 2, a detecting sensor 9 of inductance coil type for detecting eccentricity of the stator is installed with a small gap kept from the inner periphery of the stator core 4 at an end of the overhung rotary shaft 2. Therefore, the sensor 9 is installed without contacting the stator core 4. When the rotary shaft 2 is rotated, the inductance is changed by the gap difference. The eccentricity of the inner periphery of the stator to the rotary shaft 2 can be accordingly detected by the sensor 9 from this change of the inductance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an overhung type motor in which the rotating shaft of a sealed driven machine such as a compressor or a bomb is shared with the rotor of a driving motor that is integrated with the rotating shaft of a sealed driven machine such as a compressor or a bomb. This is used to measure the eccentricity of the inner circumference of the motor stator with respect to the shaft, to confirm the constant value of the gap between the motor rotor and stator, or to correct the gap if it is inconsistent. A normal motor is separated and independent from the driven machine, and its [+1
The trochanter has a structure in which it is pivotally supported at at least two points, but in an overhang structure, both are integrated and the rotating shaft on the driven machine side is used. The air gap between the inner periphery of the stator and the outer periphery of the rotor of a motor is extremely small, about 0.3-1 mm, so even a slight eccentricity of the rotor tends to cause the inner periphery of the stator and the rotor surface to come into contact. When this happens, the contact area heats up due to frictional heat and reaches a high temperature, which may cause burnout of the wire and cause damage. Mechanical deformation may cause fatal failures. Of course, after assembly, insert a thickness gauge into the gap,
'g! It goes without saying that clearance dimensions are checked, but during production, the eccentricity of the stator's inner periphery around the shaft is measured using a dial gauge attached to the drive shaft before the rotor is assembled. Conventionally, since the stator is a contact type, there is a wire ring groove on the inner periphery of the stator, and it is necessary to jump over this to measure only the tooth end surface between the wire rings. Pressure IIi! For mounds like airplanes, the frictional heat is particularly large when they are stationary, and once they begin to move around, they become ill.
Although the contact needle of the dial gauge is easily stopped at the narrow TA end, the inertia force often causes the contact needle to go too far, and this work requires unexpected effort. It is difficult. If this rotation speed is increased rapidly, the contact needle of the 6jr gauge will vibrate violently due to the ring R4, which may wear out the dial gauge itself or disturb its installation. The present invention has been made in view of these points, and will be explained based on the drawings. No. II2I shows an integrated structure in which an overhang motor 3 is coupled to a driven body 1 having a rotating shaft 2. The motor 3 has a stator core around which a wire ring 5 is wound, and a rotor 6 fitted to the rotating shaft 2 inside the stator core. FIG. 2 is a detailed R1 diagram of the motor 3, in which the stator 4 is provided with a wire groove 7 around which a wire ring 5 is wound, and stator teeth 8 between the wire wheels. Before the rotary shaft 2 is fitted to the rotary shaft 2, an inductance coil type stator eccentricity value detection sensor 9 is installed at the shaft end of the overhanging rotary shaft 2 so that there is a slight gap with respect to the inner circumference of the stator core 4. The rotary shaft 2 is rotated, and the sensor 9 detects eccentricity of the inner circumference of the stator with respect to the rotation @2 by the change in inductance caused by the gap difference. 10 is a sensor output display device, and 1l is its record Vi11. 3rd [i1m (a) is a plan view of the U-shaped detection sensor,
(A) is a side view of the iron core 2, which is the iron core 2, and an inductance wire 13 is wound around it.
(mouth) shows its side view. The tooth end 8 to the stator core corresponds to the vJ core for the iron core 12 of the inductance gland ring 13 serving as a sensor, and the change in the air gap between the tooth end 8 and the yoke l2 is detected as the wire ring of the eccentric value detection sensor 9! 3, it will be detected as an inductance change. Detection sensor in this case?
-9 in the magnetic circuit based on iron new l2, the detection sensor 9
Stator I! When t#i8 faces each other, the magnetic resistance becomes smaller and the inductance becomes larger, and as a result, the output current becomes smaller. When facing the coil groove 5, the output current becomes large, and a pulse 1ll current is generated by the coil groove. This is designated as Dn and is shown in Figure 5. In the figure, the horizontal axis is stator 4.
The vertical axis is the output current of the eccentricity value detection sensor, which is 721! between the stator 4 and rotor 6 of the motor 3. It also shows gaps. The pulsating output generated by the line vs groove 5 like the Dn curve in the figure is:
Although it is not preferable to overlap with such an eccentric value, by devising the shape of the magnetic pole tip of the detection sensor 9, the above-mentioned pulsation can be reduced and a smooth characteristic curve L4D can be obtained. That is, a smooth characteristic curve can be obtained by making the width W of the magnetic pole tip of the sensor 9 parallel to the stator radial surface to be such that it faces a large number of coil grooves and the fM end. This would make the shape of the sensor unnecessarily large, and the structure of the supporting arm and other parts would also become large, making it inconvenient to handle, so it is most preferable to minimize the shape. Pulsation and the magnetic F of said sensor! ! When examining the relationship between widths, stator tooth width LA) t. When the magnetic pole width W of the sensor is smaller, the pulsating current becomes a thicker value, but it becomes a value slightly larger than Wt, and the pulsating current decreases.If the line @full width LIJs is added to this, the phase of the pulsating current changes. reverses and increases again.
Furthermore, if the line groove body Ws is added, the 10 phases of the pulse U current become il
■and reverse, and the pulsating current gradually becomes smaller. here,@! If the magnetic pole width W of the sensor is determined when the phase of the jI current is first reversed, the sensor will be the smallest, which is advantageous both in terms of structure and measurement. If this value is determined by experiment, the optimal magnetic pole width W will be in the following range. That is,
ψg' + tJ) t > W > (1) s. This will vary depending on the capacity of the motor, the width of the ring opening, the width of the tooth end, etc., and the shapes thereof will vary, but it is sufficient to find the appropriate value for them. Next, by using the pulsation caused by the ring groove, it is possible to detect the position of the eccentricity value, which in this case is 1! I end @u)L
A pulsating output sensor for detecting the eccentricity position having a narrow magnetic pole width ω is prepared and installed together with the eccentricity value detection sensor, and by outputting and recording the outputs of both at the same time, the magnitude of the stator eccentricity value and You can easily know the location all at once. This eliminates the need to use conventional encoders that can indicate rotational position. As described above, since the sensor output is determined from the amount of change in inductance, the power source used for this is determined to have a high viscosity as a current change by using a stable high frequency rough pressure with a constant voltage and an AC bridge.

The present invention eliminates the structural and handling troubles of conventional contact methods by using a non-contact method, is highly sensitive, easy to use, and allows automatic recording of measurements and displays. You can easily perform these operations in a short time.

[Brief explanation of drawings]

Figure 1 is a front view of the integrated driven body and overhang motor, Figure 2 is a detailed view of the overhang motor, I
In Figure I, installation explanatory diagram of stator eccentricity value sensor, 3rd
4 and 4 are schematic diagrams of stator eccentricity value sensors, v. Figure 5 shows an example of a characteristic curve. 1: Driven body, 2: Rotating shaft, 3: Overhang motor 4: Stator, 5: Stator wire, 6: Rotor, 7:
Stator wire groove, 8: Stator tooth, 9: VA stator eccentricity value detection sensor - 10: Output display H position, 11: Record H position, 12: Iron core,! 3: Inductance wire.

Claims (5)

[Claims] (1) An inductance wire type stator eccentricity detection sensor is installed at the end of the overhang motor rotor shaft in a non-contact state with a slight gap between the stator core and the inner periphery of the stator core of the motor. An overhung motor stator eccentricity value measuring device, characterized in that an eccentricity value of an inner circumference of the stator core with respect to the rotor shaft is detected from an inductance change occurring in a gap between the eccentricity of the inner circumference and the sensor. (2) The overhung motor according to claim 1, wherein the eccentricity value detection sensor has a magnetic pole shape that can output the value of inductance due to the stator tooth end without being affected by the stator coil. Stator eccentricity measurement device. (3) The iron core shape of the eccentricity value detection sensor is U-shaped or I-shaped, and the magnetic pole width parallel to the stator radial surface is set to a value slightly larger than the tooth end width between the wire rings. The overhung motor stator eccentricity value measuring device according to claim 1. (4) Both the eccentricity value detection sensor and the eccentricity position detection sensor that outputs the pulsation generated in the raceway are mounted on the stator shaft end, and the outputs of the eccentricity value detection sensor and the eccentricity position detection sensor are simultaneously detected. An overhung motor stator eccentricity value measuring device according to claim 1. (5) The overhung motor stator eccentricity value measuring device according to claim 1, wherein the overhang motor stator eccentricity value measuring device is configured to simultaneously record and illustrate the outputs of the eccentricity value detection sensor and the eccentricity position detection sensor.