JPS5914973B2 - Limited angle rotation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a finite angle rotation device that uses electromagnetic force to perform a finite angle rotation operation, and is effective for use in, for example, a pickup arm drive device such as a record player. It is.

Conventionally, to drive a pickup arm of a record player or the like, the rotational driving force of a honomotor was transmitted through a gear.

As a result, the movement of the arm is slow and the waiting time until the record starts playing is long, which is extremely inconvenient for the user.

Conventionally, in order to eliminate such drawbacks, the pick-up arm was directly driven by using a slotless linear motor or by providing a winding groove in the armature core and applying a drive winding to that part. A method is proposed.

However, the former type, which uses a slotless linear motor, has problems in that it has poor conversion efficiency from electric power to torque and tends to be bulky.

In addition, in the case of the latter, which uses a rotating device in which a winding groove is provided in the armature core and a drive winding is applied, a large amount of field magnetic flux can be efficiently linked to the drive winding. Although it is possible to obtain large output with a small size and light weight,
However, when the armature core has winding grooves, the armature core has a magnetically non-uniform structure, so cogging force is generated due to interaction with the field part composed of, for example, permanent magnets. There is a problem that occurs.

Cogging force causes uneven rotational torque, so it must be kept as small as possible.

The present invention provides a finite angle rotation device that significantly reduces cogging force while using an armature core having winding grooves.

The present invention will be explained below based on illustrated embodiments.

FIG. 1 is a schematic plan view of a record player for explaining an application example of the finite angle rotation device of the present invention.

In the figure, a record disc 1 is rotated at a constant speed by a motor (not shown), and a signal is detected by a detector 3 attached to the tip of a pickup arm 2.

The pickup arm 3 is driven by a rotation device 4,
Rotation is performed within a predetermined angle θ.

It is sufficient for the rotation device 4 to rotate by a finite angle, which is sufficient for a normal record player.

The actual required rotation angle is determined by the rotation center A of the pickup arm 2, the rotation center B of the record 1, and the position C of the detector 3 when stationary, and is expressed by the following equation.

FIGS. 2 and 3 show a structural diagram of main parts and a driving circuit diagram of an embodiment of the present invention.

First, in FIG. 2, the field section 12 attached to the rotor 11 is constituted by an annular permanent magnet having an N pole and an SL on its surface.

The armature core 13 has two main salient poles 13a facing each other at the transition points of the magnetic poles of the field section 12.

13b, and auxiliary protrusions 114a, 14b arranged between the main salient poles 13a, 13b, forming a stator.

Each salient pole of the armature core 13 faces the magnetic pole of the field part 12 with a required gap, and the field part 12 is rotatable.

Note that the rotor 11 is connected, for example, to the rotation shaft of the pickup arm 2 shown in FIG.

One winding 15a, 15b is wound around each main salient pole 13a, 13b.

Note 16a. 16b, 16c, 16d are winding grooves formed between the salient poles, and 17a, 17b.

17c, 17d, 17e, 17f, 17g, 17h.

is an auxiliary groove provided to reduce cogging force.

Next, the operation of this embodiment will be explained with reference to FIGS. 2 and 3.

In FIG. 3a, when the switch S1 is turned on, the transistor Q becomes active, and a current flows through the winding 15a so that the terminal voltage of the winding 15a becomes a predetermined value.

Drive torque is generated by the current flowing through the winding 15a and the electromagnetic action of the field section 12, and the rotor 11 rotates in a predetermined direction (for example, clockwise in the figure) within the angle range of one magnetic pole of the field section 12. do.

As a result of the rotation of the rotor 11, the pickup arm 2 is rotated to a position above the record disc 1.

At this time, the schematic equilateral circuit seen from both ends of the winding 15a is as shown in Figure 3, and the current () supplied to the winding 15a decreases as the back electromotive force Ea increases due to the rotation of the rotor 11. do.

As a result, the rotor 11 does not reach a speed higher than a predetermined value, so that runaway rotation of the pickup arm does not occur.

Moreover, when switch S2 is turned on in FIG. 3a,
Current is supplied to the other winding 15b, and the rotor 11 rotates in the opposite direction to the aforementioned rotation direction, moving the pickup arm 2 away from the position above the record 1 to the outside thereof.

Furthermore, if the switch S3 is turned on while the record is being played, the inside force can be canceled.

Note that R11R2, R3, and R4 in FIG. 3a correspond to each transistor Q1. A resistor D is a diode for applying a predetermined bias to the base of Q2.

Further, R6 is a variable resistor for adjusting the degree of cancellation of the inside force.

Next, the cogging force in this example will be explained.

Cogging force is generated when the magnetic energy stored in the magnetic field changes depending on the relative position of the field part and the armature core.As shown in FIG. If there is magnetic periodicity in both, there is generally a harmonic component (matching component) that exists in both.
A cogging force is generated.

Here, the relative position of the field part 12 and the armature core 13 is 1
The effect of the auxiliary grooves will be explained by comparing the difference in the cogging force depending on the presence or absence of the auxiliary grooves 172 to 17h, assuming that the rotation changes.

Since magnetic energy is an amount related to the square of the magnetic flux density generated by the field part 12, a field part with a pitch of N[j of 165° and a pitch of S pole of 195° as shown in FIG. 1
The basic harmonic component of the magnetic period/waveform of 2 is the first harmonic component.

Here, a sine wave component generated once per rotation is defined as a first harmonic component.

That is, the field section 12 is based on the first harmonic component,
This means that it contains second-order, third-order, etc. harmonic components.

On the other hand, the magnetic non-uniformity of the armature core 13 is caused by the winding groove 16
3 to 16d and auxiliary grooves 17a to 17h.

First, if we consider the case where no auxiliary grooves are provided, the winding grooves (16a, 16d) and (16b).

16c) are at 180° opposite positions, the fundamental harmonic component of the magnetic non-uniformity of the armature core 13 is the second-order component.

Therefore, based on this, the 4th, 6th, etc.
It also contains harmonic components such as...

The cogging force is a match between the magnetic non-uniformity component of the armature core 13 and the harmonic component of the field section 12.
Since the cogging force is generated when the auxiliary grooves 17a to 17h are not provided, the cogging force is of the second order, fourth order, sixth order, etc.
Mainly harmonic components such as... are generated.

Armature core 13 of this embodiment. are auxiliary grooves 17a to 17h
, the state of magnetic inhomogeneity changes, and as a result, the cogging force in the embodiment of FIG. 2 is significantly smaller.

This will be explained below with reference to FIG.

FIG. 4 is a diagram representative of the distribution of magnetic flux in the winding groove 16a near sunset.

In the figure, most of the magnetic flux flowing out from the field portion 12 is absorbed by the tip of the salient pole of the armature core 13, avoiding the groove with high magnetic resistance, as indicated by the arrow line.

As a result, the magnetic flux in a portion deeper than the broken line H shown in the figure becomes extremely small.

Therefore, even if the depth of the groove 16a is deeper than the broken line H, it is magnetically almost the same as the depth of the broken line H.

The same applies to the other winding grooves 16b, 16c, and 16d.

Therefore, as illustrated in Fig. 2, even if the auxiliary groove is an open groove having a width approximately equal to that of the winding groove and is shallower than the winding groove, it may be equivalent to or less than the winding groove. Almost the same magnetic effect can be obtained.

In this embodiment, the positions where the center distance between the grooves at both ends of the main flames It13a and 13b are equally divided into four, and the auxiliary salient poles 14a and 14
It is provided at a position that equally divides the center distance between the grooves at both ends of b.

That is, the winding grooves 16a to 16d and the auxiliary grooves 17a to 1
7h are arranged at equal angular intervals (30° intervals) or approximately at equal angular intervals with respect to the center of rotation A.

Therefore, the basic component of the period/waveform of the magnetic non-uniformity of the armature core 13 of this embodiment is the 12th harmonic component, and its harmonic components are the 24th, 36th, . . . ...
... etc. will be included.

As a result, the cogging force is mainly 12th and 24th order.
Harmonic components such as the 36th order and the 36th order are generated.

Comparing the above results with the case where auxiliary grooves 17a to 17h are desired, 2.4, 6, 8, 10° 14.16...
......The cogging force of the harmonic components such as the next order is missing (or decreased), and the order of the fundamental harmonic component of the cogging force is the second order in the case without the auxiliary groove. However, by providing an auxiliary groove, the 6th order, such as the 12th
It is twice as high-order.

Generally, the magnitude of each component of the cogging force is related to the product of the magnitude of the corresponding component in the armature core and the magnitude of the corresponding component in the field part, and as the product becomes smaller, the magnitude of the corresponding component of the cogging force increases. The size also becomes smaller.

In addition, the harmonic components of the field section normally attenuate in magnitude more quickly as they become higher-order components, so the 12th harmonic component is usually quite small compared to the 2nd-order component. It is.

Therefore, by providing the auxiliary grooves as in the present invention, not only the number of harmonic components of the field part and armature core that can be involved in cogging force are reduced, but also the fundamental harmonic components of cogging force are reduced. Due to the higher order, the cogging force is significantly reduced.

Furthermore, when one of the switching poles of the field section 12 faces a groove (winding groove or auxiliary groove), the switching of the other pole faces a protrusion, thereby reducing the cogging force. It can be made even more efficient.

In addition, in the above-mentioned embodiment of the present invention, the field part is the rotor and the armature core is the stator, but the present invention is not limited to such a structure, and the relationship may be reversed. It may be.

Moreover, it is not limited to the external rotation type, but may be an internal rotation type.

FIG. 5 shows a structural diagram of main parts of another embodiment of the present invention.

In the figure, a field section 22 attached to a rotor 21 is constituted by an annular permanent magnet having an N pole and an SL on its surface.

The armature core constituting the stator includes a main salient pole body 23 having two main salient poles 23a and 23b, and two auxiliary salient poles 't2.
The main salient pole structure 23 and the auxiliary salient pole structure 24 are magnetically and mechanically connected and fixed.

Main salient poles 23a, 23b and auxiliary salient pole 2 of armature core
4a and 24b face the magnetic poles of the field section 22 with a required gap, and the field section 22 is rotatable relative to the armature core.

Each main salient pole 23a. 23b has a winding 25a serving as a drive winding.
, 25b are wound, and the rotor 21 is rotated in a predetermined direction by supplying current in a predetermined direction to the windings 25a and 25b.

Also in this embodiment, each winding groove 26a, 26b.

Auxiliary grooves 27a, 27b, 27c, 27d, and 27e have substantially the same magnetic effect as 26c and 26d.

27f, 27g, 27h, 27i, 27j, 27k.

2713.27m, 27n, and 27o are provided, and the entire odd number (19) grooves consisting of winding grooves 263 to 27d and auxiliary grooves 27a to 27o are arranged at equal angular intervals (360°/
They are arranged at approximately equal angular intervals (19 x 18.95° intervals) or at approximately equal angular intervals.

Therefore, the fundamental harmonic component of the magnetic non-uniformity of the armature core of this embodiment is the second harmonic component when there is no auxiliary groove, but the 19th harmonic component when there is an auxiliary groove. Becomes a fire component.

On the other hand, the basic components of the magnetic period and waveform of the field section are second-order.

As a result, the basic component of the cogging force is secondary in the absence of the auxiliary grooves, whereas
If it is provided, the order becomes 38th order, which is 19 times higher order.

As a result, the cogging force in this embodiment is significantly reduced.

If the auxiliary salient pole structure is separate from the main salient pole structure of the armature core, as shown in the embodiment shown in FIG. Since it is only necessary to attach the auxiliary salient pole structure, winding becomes easy, which is advantageous in terms of manufacturing.

Of course, the present invention is not limited to such a structure, and as illustrated in FIG. You can also make an armature core by laminating some of them).

In this case, the shape and precision of the winding groove and the auxiliary groove are determined by the mold, so there is less variation during mass production, and the effect of reducing cogging force is more stable.

Moreover, if the depth of the auxiliary groove is made shallow and the base part of the main salient pole is made narrower than the tip part, the space for storing the winding wire can be increased, resulting in an efficient rotating device.

Furthermore, the width of the auxiliary groove is equal to the width of the winding groove, or
If they are made approximately equal, magnetically almost the same effect as the winding groove can be easily obtained.

Of course, it goes without saying that the cogging force can be reduced even if the auxiliary groove has the same or almost the same shape as the winding groove.

Further, as shown in the above embodiment, if the total number of armature core grooves (winding grooves and auxiliary grooves) is made an odd number, the cogging force can be easily reduced.

Therefore, a dedicated speed detection winding may be used to control the energizing current.

Furthermore, two winding materials can be wound around the same main salient pole at the same time.
drive windings may be formed.

In addition, the horizontal component of low-frequency resonance of a rotating member such as a pickup arm is detected by the generated voltage generated in the winding.
Compensation and control are also possible.

As is clear from the above description, the present invention can provide a finite angle rotation device that is efficient and has a small cogging force.

Therefore, if a pickup arm drive device for a record player or the like is constructed based on the present invention, a high-performance device with quick response can be realized.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of a record player, FIG. 2 is a structural diagram of main parts of an embodiment of the present invention, and FIG. 3a. b is a diagram showing the drive circuit of the same embodiment and an equivalent circuit of the same essential parts;
Figure 4 is a diagram showing the magnetic flux distribution of the main parts of the same example.
6 and 6 are structural diagrams of main parts of another embodiment of the present invention, respectively. 11.21.31...Rotor, 12,22,3
2... Field part, 13.33... Armature core, 23... Main salient pole structure, 24...
- Auxiliary salient pole structure, 13a. 13b, 23a, 23b, 33a, 33b=-
---Main salient poles, 14a, 14b, 24a, 24b=
...Auxiliary salient poles, 15a, 15b, 25a, 25b
, 34a. 34b... Winding, 16a-16d, 26a-2
6d. 35a, 35b...Winding groove, 17a
~17h. 27 a to 27 o, 36 a to 36 g...-auxiliary groove.

Claims (1)

[Scope of Claims] 1. A field portion formed by a permanent magnet having a smooth magnetic pole surface; an armature core having a winding groove disposed opposite to the magnetic pole surface of the field portion; One or more drive windings are wound in the winding groove, and by energizing and exciting the drive winding, the field part and the armature core are
A device for rotating one of the two by a finite angle with respect to the other, wherein at least one salient pole of the armature core is provided with two or more auxiliary grooves, the winding groove and the auxiliary groove. The finite angle rotation device is characterized in that the entire grooves are arranged at equal angular intervals or approximately at equal angular intervals with respect to the center of rotation, and the auxiliary groove is formed shallower than the winding groove. 2. Claim No. 2, characterized in that the field portion is formed by an annular permanent magnet having a plurality of magnetic poles, and the magnetic pole width of the permanent magnet is a non-integral multiple of the gap between the grooves of the armature core. The finite angle rotation device according to item 1.