JPH0191649A - Stepping motor - Google Patents

Abstract

PURPOSE:To make it possible to adjust starting characteristic in the best condition by providing an adjusting means to adjust the driving force of a rotor by magnetic force occured in one stator to the driving force of the rotor occured in the other stator. CONSTITUTION:A stepping motor M is constituted of a rotor R consisting of permanent magnet which is supported rotatably to a shaft 1 and which multipolar magnetization was made in the direction of diameter, two stators SA and SB to form a pole opposed to a magnetic pole of the rotor R and coils LA and LB fitted and inserted into each stator, and the coils LA and LB are connected to a control circuit Q. The stator SA is supported to a substrate of the motor M by off-center shafts SA1 and SA2, and a void between a pole of the stator SA and the magnetic pole of the rotor R is adjusted by adjusting rotation of the off-center shafts SA1 and SA2. Similarly, the stator SB is supported to the substrate of the motor M by the off-center shafts SB1 and SB2, and a void between a pole of the stator SB and the magnetic pole of the rotor R is adjusted by the off-center shafts SB1 and SB2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an adjusting device for a step motor, and particularly to an adjusting device for obtaining smooth starting characteristics of a step motor capable of forward and reverse rotation.

[Prior art] A step motor that obtains driving force by controlling a rotor that rotates forward and reverse has extremely good responsiveness, making it possible to perform fine control. When a driving force is required, the rotor has four magnetic poles and is driven by two sets of stators, which causes an unstable state at the initial stage of startup due to manufacturing errors in each component.

In other words, the air gap between the rotor's magnetic poles and the multipole of the stator is not uniform due to the fit gap of the rotor support shaft, the mounting position error of each stator, etc., and the gap between the rotor's magnetic poles and the multi-poles of the stator is not uniform. Current errors due to variations in specifications, etc. all directly affect the starting characteristics of the rotor driven by the stator.

Based on these factors, in order to improve the starting characteristics, the present applicant proposed a method in which the energization time within the period of the pulse that energizes the stator coil is made variable. (Special application 1986
(No. 81641) However, in this method, experimental data is collected for a specific type of step motor,
Based on this, the optimum energization time was determined and the constants of the electronic circuit were set. Once a constant is set for that type of motor, production continues with that constant and cannot be easily changed.

Therefore, it is difficult to deal with variations in various factors for individual motors, and there is a problem in that starting characteristics cannot necessarily be maintained in the best condition.

Camera shutters need to operate quickly and smoothly, but with the method described above, it is difficult to adjust each motor to start smoothly, so the aperture diameter is The amount of change is not stable, causing variations in the exposure amount, making it difficult to accurately control the exposure amount.

[Purpose] In view of the above-mentioned drawbacks, it is an object of the present invention to adjust the starting characteristics to the best condition each time even when each element of an individual step motor changes.

[Means for Achieving the Object] In order to achieve the above object, the present invention features a rotor rotatable around a support shaft and magnetized in the radial direction, and a plurality of rotors facing the outer periphery of the rotor. It is equipped with a plurality of stators formed with magnetic poles, a coil that excites each stator, and an electronic circuit that controls energization of the coil. An adjustment means is provided to adjust the rotor drive that occurs in the stator.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.
In the figure, a step motor M is rotatably supported by a shaft 1, and has a rotor R consisting of a permanent magnet magnetized with multiple poles (four poles in this example) in the radial direction, and a pole opposite to the magnetic pole of the rotor. It consists of two stators SA and SB, and coils LA and LB fitted into each of the stators.
A.

LB is connected to a known control circuit Q.

The stator SA is supported by the substrate of the motor M by eccentric shafts SAI and SA2, and by adjusting the rotation of the eccentric shafts SA1 and SA2, the poles of the stator SA and the rotor R are
The air gap with the magnetic pole is adjusted.

Similarly, stator SB has eccentric shaft SB1. It is supported by the board of the motor M by SB2, and the eccentric shaft SBI, SB2
Thus, the gap between the poles of the stator SB and the magnetic poles of the rotor R is adjusted.

In FIGS. 2 and 3, a pinion 2 for transmitting the rotation of the motor M is fixed to the tip of the output shaft 1 of the step motor M. Reference numeral 3 denotes a base plate for holding the lens, and a base plate 4 is attached to the lower surface side with screws. An aperture O for a lens aperture is formed at the center of the base plate 3 and base plate 4, and a sector chamber R for storing a sector 5, which will be described later, is formed between them. A sector drive lever 6 is rotatably supported by a rotary shaft 3a provided on the main plate 3, and is supported by the lower surface of the board of the step motor M so as not to be pulled out. A sector drive wheel 7, which will be described later, is rotatably attached to the sector drive lever 6, and a groove 6b provided on the sector drive lever 6 and an adjustment pin 8, which will be described later, fixed to the sector drive wheel 7 are engaged with each other. In addition, relative rotation between the sector drive lever 6 and the sector drive wheel 7 is restricted. Further, the sector drive lever 6 has a protruding sector pin 6a that passes through the main plate 3 and engages with the groove of the sector 5. Further, the sectors 5, 5 are rotatably supported by pins 3b, 3b provided on the main plate 3, respectively,
The aperture aperture is determined by two sectors 5.5 arranged symmetrically. The sector drive vehicle 7 attached to the sector drive lever 6 is an idler vehicle 9 which will be described later.
It has a tooth portion 7a that meshes with the main plate 3, a rotation portion 7b that comes into contact with a pin 3C provided on the base plate 3 to restrict rotation, and a pin 7C that engages with a spring 10. biased in the direction. The adjustment pin 8 fixed to the sector drive wheel 7 has a diameter portion that engages with the sector drive wheel 7 and a diameter portion that engages with the groove portion sb of the sector drive lever that are eccentric, and the diameter portion that engages with the sector drive wheel 7 is eccentric. It is rotatably fixed with a predetermined friction slip torque by caulking or the like. Therefore, by turning the groove portion of the adjustment pin 8 with a screwdriver or the like, the phase relationship between the tooth portion 7a of the safety drive wheel 7 and the sector pin 6a of the sector drive lever 6 can be adjusted. The idler wheel 9 has a pinion 9a that meshes with the teeth 7a of the sector drive wheel 7.
and a gear 9b that meshes with the pinion 2, and is rotatably supported by a rotating shaft 3d provided on the main plate 3.
It is supported by the lower surface of the board so that it does not come out. Further, the base plate 3 has a protruding pillar 3e for mounting the step motor M, and the step motor M is attached to the set screw 1.
By being fixed to the pillar 3e by the pinion 2 and the idler wheel 9, the pinion 2 and the idler wheel 9 can engage and transmit rotation.

Next, the method of operation will be explained. When a known control circuit Q is operated, two coils LA are activated.

A bipolar drive two-phase excitation force type drive signal is output to LB, the stators SA and SB are excited, and the rotor R rotates the sector 5 via the transmission system shown in the figure by the right-handed turning pinion 2, thereby opening the opening. Open 0.

Hereinafter, the rotor R turns to the left and the sector 5 closes the opening O by a known method, but since this is a known method, detailed explanation will be omitted.

What should be noted here is that the stators SA, SB have eccentric shafts SAI, SA2. By adjusting the rotation of SBI and SB2, it is possible to adjust the air gap between the magnetic poles of the rotor R and each of the stator magnetic poles facing it, so that the operation of the rotor R, especially at the initial stage of rotation, caused by the above-mentioned factors can be adjusted. In order to make this smooth, eccentric shafts SAI, SA2. By rotating SBI and SB2, the tap motor M can be adjusted to the best condition.

That is, the gap between rotor R and stator SA or SB is
The stator pole closest to the rotor magnetic poles is adjusted so as to strongly drive the rotor R when a large load is applied to the rotor shaft 1.

In other words, the rotor R operates under a relatively light load while absorbing the backlash occurring in each transmission system among the aforementioned factors, but the load increases as each element is driven.

It is not possible to unambiguously determine which stator pole should optimally correspond to which magnetic pole of the rotor R, and it cannot be determined unless each step motor M is in a completed state.

Note that the eccentric shafts SAI, SA2. SBI and SB2 may not all be provided, but may be provided as needed, and only one may be provided.

FIG. 4 shows a second embodiment, in which an eccentric pin E supporting the rotor shaft 1 is coupled to the upper plate P1 of the step motor M.
A shaft 1 is pressed against the conical portion on the lower surface side. Also, the lower plate P
A leaf spring P3 is fixed to the rotor shaft 1, and the conical part of the shaft 1 fits into the hole at the tip of the leaf spring P3.
3, it is pressed against the eccentric bin E side.

The operating method of the rotor R is the same as that in the above embodiment, so the description thereof will be omitted. However, the gap between the rotor R and the stators SA, SB can be adjusted by rotating the eccentric bin E so that the conical part of the eccentric bin E is aligned with the upper plate P1. The rotor is displaced.

FIG. 5 shows a third embodiment, in which the rotor R, stator SA
, SB does not have an adjustment section, but is connected to a regulator V that adjusts the current in the coil LB. By adjusting the current in the coil LB, the balance between the stator SB and the stator SA with respect to the rotor R is maintained. , thereby smoothing the startup of the rotor R.

Note that although the regulator V regulates the current of the coil LB, it may also regulate the voltage of the coil terminal.

Moreover, the same effect can be obtained even if the regulator V is provided for the coil LA.

As mentioned above, the magnetic poles of rotor R and stators SA, SB
It is clear that there are other embodiments that follow the above-mentioned principle and that smooth the startup of the rotor R by adjusting the gap between the rotor and the drive force and balancing the driving force.

[Effect] As is clear from the above explanation, the influence of various factors unique to each step motor can be achieved by adjusting the air gap between the corresponding magnetic poles of the rotor and stator, or adjusting the magnetic force on the stator side. By this means, a step motor with smooth starting characteristics can be obtained.

Therefore, the fitting gaps of each part, the stator mounting position error,
Adjustments can be made to reduce the effects of uneven rotation of the rotor caused by stator shape errors, rotor magnetization strength, angle errors, etc., so each of the above parts can be used without having to control the machining accuracy as strictly as before. Yes, an inexpensive step motor can be obtained.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a plan view of the main body of the step motor, FIG. 2 is a plan view of a camera shutter driven by the step motor, and FIG. 3 is a partial cross section of FIG. 2. 4 are sectional views of essential parts showing the second embodiment, and FIG. 5 is a plan view showing the third embodiment.゛M...Step motor, R...Rotor, SA, SB...Stator, LA, LB...Coil, Q...Control Circuit, ■...Adjuster, 1...Rotor shaft, 2...Pinion, 5...Sector, 6...Sector drive /<-1 7...Sector drive vehicle. that's all

Claims (1)

[Claims] A rotor rotatable around a support shaft and magnetized in the radial direction, a plurality of stators each having a plurality of magnetic poles facing the outer periphery of the rotor, a coil for exciting each of the stators, and the coil. an electronic circuit for controlling energization of the coil, and adjusting means for adjusting the rotor driving force caused by the magnetic force generated in the one stator when the coil is energized with respect to the rotor driving force generated in the other stator. A step motor characterized by: