JPS5831834B2 - rotary drive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary drive device such as a motor.

Generally, the efficiency of a motor is closely related to the rotational speed used, and as the rotational speed decreases, the efficiency decreases almost proportionally.

Therefore, efficiency is significantly reduced for applications requiring low or very low rotation speeds.

Therefore, there has been a desire for a rotary drive device that is efficient even when rotating at low speeds.

The present invention takes these points into consideration and provides a rotary drive device that is efficient during low speed rotation and has small fluctuations in output torque.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1a is a partial sectional view of a rotary drive device in an embodiment of the present invention.

In the figure, a pulse motor 2 is driven by a pulse drive circuit 1 and rotates in a stepwise manner.

The drive side rotating body 4 is fixed to the rotating shaft 3 of the pulse motor 2.

Therefore, the rotor rotating shaft 3 of the pulse motor 2 and the drive-side rotating body 4 rotate together.

The output side rotating body 5 is arranged coaxially with the driving side rotating body 4,
Both are relatively unrotatable.

Two-pole magnetized magnets 6 and 7 face each other on the outer periphery of the drive-side rotary body 4 and on the inner periphery of the output-side rotary body, separated by a required gear distance.

This relationship is shown in Figure 1. Therefore, magnet 6.7
The magnetic attractive force or repulsive force acts, and the drive side rotating body 4
A torque φ corresponding to the displacement difference X of the output side rotating body 5 is generated.

The characteristic is a saturation characteristic (as X becomes larger, the slope dφ/dx becomes smaller) as shown in FIG.

As a result, the output side rotating body 5 is rotationally driven by the torque φ corresponding to the displacement difference X.

An output gear 8 is fixed to the output rotating body 5, and the gear 8 rotationally drives the other rotating bodies.

Gear 8 has equal angular intervals 41 to transmit and block light!
! Holes are provided at equal angular intervals, and the rotational position of the gear 80 is detected by the light emitting element 9 and the light receiving element 10.

The output signal of the light receiving element 10 is given to the pulse drive circuit 1 every time the output side rotating body 50 rotates by a predetermined angle, and the pulse drive circuit 1 drives the pulse motor 2 in a pulsed manner to move the drive side rotating body 4 in steps of a predetermined angle. Displace it at high speed.

Therefore, the displacement difference X between the drive-side rotary body 4 and the output-side rotary body 5 can be set within a predetermined range (the portion ΔX in FIG. 2) within the saturation characteristic, and as shown in FIG. The torque φ generated at 70 is a substantially constant value.

As a result, the output rotating body 5 is rotationally driven with a constant or almost constant torque in the same direction.

Note that the drive-side rotating body 4 and the rotor rotating shaft 3 are prevented from reversing in a non-contact manner by cogging torque between the field magnet of the pulse motor 2 and the armature core.

That is, the cogging torque is made larger than the torque generated by the magnet 6.7, and the rotor of the pulse motor 2 and the drive-side rotating body 4 come to rest at a point where the torque generated by the magnet 6.7q' and the cogging torque are balanced. Reversal is prevented.

Further, the driving rotary body 4 and the output side rotary body 5 are provided with engaging portions A and B, which are displacement difference limiting means, to limit the range of the displacement difference between the two.

In this example, as shown in FIG.
*

To summarize the above description, the rotary drive device of the present invention comprises a drive side rotary body 4, an output side rotary body 5, and a pulse drive means (pulse drive circuit 1 and (equivalent to pulse motor 2) and drive-side rotating body 4
and a displacement difference-torque conversion means (corresponding to a magnet 6° 7) that rotationally drives the output side rotor 5 according to the relative displacement difference between the output side rotor 5 and the output side rotor 5. ,
Displacement detection means (corresponding to the gear 8, light emitting element 9, and light receiving element 10) that operates the pulse drive means, and a displacement difference limiter that limits the displacement difference between the drive side rotary body 4 and the output side rotary body 5 within a predetermined range. means (corresponding to the engaging parts A and H).

Next, the efficiency of the rotary drive device of the present invention will be explained.

In response to the output of the displacement detecting means, the pulse driving means supplies large electric power in a pulsed manner to the motor 2 to drive the rotating body 4 on the driving side.
is rotated and displaced at high speed in a pulsed manner (instantaneously).

When the power supply to the motor 2 is stopped, the drive-side rotating body 4 comes to rest at a point where the torque generated by the magnet 6.70 and the cogging torque are balanced.

That is, in this rotary drive device, electrical input is made in a pulsed manner, which is temporarily converted into potential energy of the displacement difference/torque conversion means and stored, and then during a period when the pulse drive means stops supplying power, Gradually the output side rotating body 5
It is used as rotational energy and output energy.

The efficiency of the rotary drive device is determined by the conversion ratio of the electrical input to the motor 2 of the pulse drive means into mechanically useful energy.

Since this rotary drive device performs electrical input intermittently in pulses, the motor efficiency (conversion rate from electrical input to potential energy of the displacement difference-torque conversion means) during the period of pulsed electrical input is ) and the conversion efficiency from the potential energy of the displacement difference/torque conversion means to the output energy of the output rotating body 5, the total efficiency is calculated.

The efficiency of the latter is usually much better, and the overall efficiency is greatly influenced by the motor efficiency.

Generally, motor efficiency improves as the rotational speed of the motor increases.

That is, the rotational speed when power is being supplied becomes a problem.

In this rotary drive device, since a large pulse-like electric power is supplied to the drive motor 2 to perform high-speed rotation and displacement, the average rotational speed during this period is high.

Therefore, the motor efficiency is improved and the overall efficiency is also increased.

Furthermore, since the motor efficiency is almost unrelated to the rotational speed of the output-side rotary body 5, the overall efficiency does not decrease (is large) even when the output-side rotary body 5 rotates at low speed and at very low speed.

Therefore, the rotary drive device of the present invention is highly efficient and has extremely small fluctuations in output torque.

As shown in the above embodiment, if magnetic attractive force or repulsive force is used as the displacement difference-tortor conversion means, the saturation characteristic (as the displacement difference X increases, the slope dφ/d
) can be obtained.

In particular, if two magnets are used, one magnet is fixed to the drive-side rotating body, the other magnet is fixed to the output-side rotating body, and both magnets are placed facing each other with a required gear spacing, the magnetization will be fixed. The structure is simple.

Note that the two magnets may be opposed to each other with an axial gap interposed therebetween.

Further, the number of poles of the magnet is not limited to two, but it is better to have a smaller number of poles because the range of constant torque can be wider.

Further, it is desirable that the back yoke of the magnet is made of iron.

Also, so that the displacement difference is always within the flat part of the saturation characteristic,
It is preferable to reduce the displacement detection angle of the output side rotary body to some extent and operate the pulse drive means at least multiple times for one rotation of the output side rotary body.

Furthermore, as shown in the above-mentioned embodiment, if a displacement difference limiting means is provided to keep the displacement difference between the drive-side rotor and the output-side rotor within a predetermined range, the range of the displacement difference will be accurate and the drive torque will be reduced. Fluctuations can be reduced.

In particular, if both the drive-side rotary body and the output-side rotary body are each provided with at least one engagement portion such as a protrusion to function as a displacement difference limiting means, the structure will be simple and the number of parts will increase. do not have.

Furthermore, a reversal prevention means that prevents the drive-side rotating body from rotating in the opposite direction in response to reverse torque within a predetermined range is provided, for example, by using cogging torque that acts between a magnet and a magnetic material (such as iron or a magnet). If provided, the cogging torque is a non-contact reversal prevention means, and the noise and vibration inherent in mechanical latch mechanisms are reduced.

In particular, if a motor consisting of a multi-pole magnetized field magnet and an armature core having a plurality of magnetic protrusions is used as a pulse drive means, the cogging torque between the field magnet and the armature core is reversed. The structure is simple because it can be used as a prevention means.

The aforementioned pulse motor is also an example of this.

However, the pulse drive means and reverse rotation prevention means of the present invention are not limited to such a case.

For example, if a DC motor and mechanical latch mechanism are installed,
Or, a case where a continuously rotating stationary rotating body, a clutch that intermittently connects the stationary rotating body and the driving side rotating body, and a mechanical latch mechanism that prevents the driving side rotating body from reversing are provided. can also be applied.

Further, as shown in the above-mentioned embodiments, if the drive-side rotary body and the output-side rotary body are arranged coaxially, the structure becomes simple.

In particular, if the rotor and rotating shaft of the motor, which are part of the pulse drive means, are used as the drive-side rotating body, the number of parts will be reduced and manufacturing will be easier.

Furthermore, in the above-described embodiment, the rotational position of the output-side rotary body is detected to activate the pulse drive means, but the present invention is not limited to such a case. It goes without saying that the pulse driving means may be operated by the following steps and is included in the present invention.

Furthermore, the displacement detection means is not limited to the optical method, and there are many other methods such as a magnetic method using a magnet and a Hall element, or a high frequency coupling modulation method.

In particular, the method of detecting the displacement (rotational position or displacement difference) of the output-side rotary body in a non-contact manner is free from torque fluctuations due to contact and is highly reliable.

It goes without saying that various other modifications can be made without changing the spirit of the invention.

The rotary drive device of the present invention has small fluctuations in output torque and is highly efficient, so it can be used as a drive device for various types of equipment.

It is particularly suitable for equipment that requires constant torque performance.

[Brief explanation of drawings]

FIG. 1a is a cross-sectional view of a main part of a rotary drive device according to an embodiment of the present invention, the same figure is a cross-sectional view of a main part of an example in which a magnet is used as the displacement difference/torque conversion means, and FIG. FIG. 3 is a diagram showing characteristics of torque converting means. 1...Pulse drive circuit, 2...Pulse motor, 3...Rotor rotation axis, 4...
Drive side rotating body, 5... Winding side rotating body, 6, 7.
...Magnet, 8...Output gear, 9
...... Light emitting element, 10... Light receiving element.

Claims (1)

[Scope of Claims] 1. A drive-side rotating body, an output-side rotating body, and a pulse drive means that includes a motor to which large electric power is supplied in a pulsed manner and rotates the driving-side rotating body in a pulsed manner; Displacement difference-torque conversion means for rotationally driving the output side rotary body according to a relative displacement difference between the side rotary body and the output side rotary body, and actuating the pulse drive means according to the displacement of the output side rotary body. and displacement difference limiting means for limiting the displacement difference between the drive-side rotary body and the output-side rotary body within a predetermined range, and the displacement difference X of the displacement difference-torque conversion means.
The slope dφ/dx of the generated torque φ with respect to the torque φ has a characteristic that it decreases as X increases, and the displacement difference limiting means is configured to prevent the displacement difference X from falling outside a predetermined range. rotary drive device. 2. A rotary drive device according to claim 1, characterized in that magnetic attraction or repulsion is utilized as the displacement difference-torque conversion means. 3 In claim 2, two magnets having a plurality of magnetic poles are used as the displacement difference-torque converting means, one magnet is fixed to the drive-side rotating body, and the other magnet is fixed to the output rotating body. Fixed to the side rotating body,
A rotary drive device characterized in that both magnets are configured to face each other at a required distance and rotate coaxially or substantially coaxially. 4. The rotational drive device according to claim 3, wherein each of the two magnets has two magnetic poles. 5. The rotary drive device according to claim 1, wherein one or more engaging portions are provided on each of the drive-side rotary body and the output-side rotary body as the displacement difference limiting means. 6. The rotary drive device according to claim 1, characterized in that the drive-side rotary body and the output-side rotary body are disposed on the same axis so as to be relatively rotatable.