JPS5852564B2 - Mirror rotation control element - Google Patents

Description

[Detailed description of the invention] The present invention relates to a mirror rotation control element.

A moving coil type rotating device has been known for a long time, and it was possible to use this rotating device as a vibrating device for a reflecting mirror. In addition to the primary resonance determined by the inertial mass of the vibrating part of the vibrating device and the spring constant of the return spring that returns the mirror to a fixed position, the inertial mass of the drive coil part, the inertial mass of a part of the mirror, and the torsion of the output shaft are Torsional resonance determined by the rigidity occurs.

At this time, the movement of a part of the mirror with respect to the drive input has a phase delay of nearly 1800 due to primary resonance, and a further phase delay of 1800 due to torsional resonance.
00 and will be late.

When using this mirror vibrating device for control, if the torsional resonance frequency is lower than the primary resonance frequency, the control gain of the control system cannot be high.

Therefore, in order to obtain a high control gain, it was necessary to reduce the inertial mass of the vibrating section or to increase the thickness of the output shaft.

However, there is a limit to the inertial mass of the vibrating part, and if the output shaft is made thicker, the resistance of the bearing part will increase proportionally, resulting in a dead zone that does not respond to small inputs, making it unsuitable for control. It had become something.

Furthermore, since the output shaft passes through the center of the core magnet, a hole is required at the center of the core magnet, and as the output shaft becomes thicker, a larger hole becomes necessary.

Therefore, the magnetic flux becomes smaller, and in order to obtain the same output,
More input was required.

The present invention has been made to solve the above problems, and aims to increase the control gain and the efficiency of the vibration device.

The present invention will be described below based on drawings showing an example of implementation.

FIG. 1 is a cross-section of the mirror rotation control element of the present invention, showing 1
2 is a light reflecting mirror, and 2 is a support for the light reflecting mirror 1.

3 is a rotating shaft of the light reflecting mirror 1, 4 is a bearing of the rotating shaft 3, and 5 is a solid core magnet 6 magnetized in a direction perpendicular to the axis of the rotating shaft 3. This is a case outer cylinder that is arranged concentrically with the case and forms a closed magnetic path.

Reference numeral 7 denotes a case side plate that fixes the core magnet 5 and the case outer cylinder 6 in a fixed position.

Reference numeral 8 denotes a drive coil, which is wound so as to have a component in a direction parallel to the rotation axis 3.

Reference numeral 9 denotes a coil support member for coupling the drive coil 8 to the rotation shaft 3.

The above rotation shaft 3, drive coil 8, and coil support member 9 constitute a coil rotator.

10 is a return spring that returns the coil rotator to a fixed position.

Reference numeral 11 denotes a bearing side plate for mounting the bearing 4 of the rotating shaft 3.

In the present invention, one bearing 4 is provided between the core magnet 5 and the coil support member 9 as shown in FIG. It is provided via a mirror 1.

Furthermore, the core magnet 5 is solid.

By the way, FIG. 2 shows a conventional example, where 21 is a light reflecting mirror;
22 is a support for the light reflecting mirror 21.

23 is the rotation axis of the light reflecting mirror 21, and 24 is the rotation axis 23.
This is a bearing.

25 is a core magnet, 26 is a case outer cylinder, and 27 is a case side plate.

28 is a drive coil, and 29 is a coil support member for the drive coil 28.

30 is a return spring, and 31 is a dustproof cover.

As described above, in the past, the core magnet 25 had a rotary shaft 230 with a through hole in the center, which caused a decrease in magnetic flux.

Furthermore, due to the rigidity of the rotating shaft 23, torsional resonance occurs at a low frequency.

If the shaft diameter of the rotating shaft 23 is increased in order to increase the tilt resistance, a dead zone will occur due to the resistance in the bearing 24, and problems such as the need to increase the hole diameter of the core magnet 25 will arise, resulting in low torsional resonance. I used it and couldn't get a high gain.

Therefore, the present invention is constructed as shown in FIG. 3 and the like.

First, FIG. 3 is an explanatory diagram of the rotation axis. That is, by attaching the light reflecting mirror 1 to the rotating shaft 3, the rotating shaft 3 also serves as a support for the light reflecting mirror 1.

Both ends of the rotating shaft 3 protrude conically, and the bearing 4 has an inverted conical recess into which the conical protrusion is fitted.

By doing the above, a support body for the light reflecting mirror 1 is not required, so that the inertial mass can be reduced and the torsional resonance frequency can be increased.

Further, FIG. 4 is a diagram showing an embodiment in which the bearing is supported by an elastic body.

That is, 12 is an elastic body such as rubber, which is interposed between the two bearings 4, 4, the core magnet 5, and the bearing side plate 11.

By supporting the bearing 4.degree. 4 with the elastic bodies 12, 12 in this manner, a certain preload can be applied to the bearing 4.degree. 4, and play in the bearing can be eliminated.

FIG. 5 is a graph showing the phase characteristics and amplitude characteristics when the vibrating device has primary resonance and further has torsional resonance.

The left vertical axis shows amplitude, the right vertical axis shows phase delay, and the horizontal axis shows frequency.

The solid line is the amplitude characteristic.

This figure shows the case where damping is applied.

The broken line is the phase characteristic when there is no torsional resonance, and ideally the phase delay does not exceed 1800.

The dashed-dotted line shows the phase characteristics when there is torsional resonance at a low frequency.

The two-dot chain line shows the phase delay when there is torsional resonance at a high frequency.

As shown in the figure, the higher the torsional resonance frequency is, the more the phase delay is 180
Frequencies that exceed ° become higher.

The higher the frequency at which the phase delay exceeds 1800, the higher the control gain G becomes.

For example, if the frequency of torsional resonance is low, only a control gain of 01 can be obtained, but if the frequency of torsional resonance is high, a control gain of G2 can be obtained.

Although elastic bodies are attached to both bearings in FIG. 4, it is also effective to attach only one bearing.

Further, although both the shaft and the bearing are shown in a pivot shape in FIGS. 3 and 4, the present invention is not limited to this.

Furthermore, FIG. 6 shows a coil support member and a support body for the light reflecting mirror 1 which are integrally molded.

Reference numeral 13 denotes a mirror coil support member that is integrated with the rotation shaft.

Although not shown in the drawings, by forming the support of the light reflecting mirror from a material having a coefficient of thermal expansion comparable to that of the light reflecting mirror, such as glass, ferrite, ceramic, or other ceramics, the mirror supporting member and the coil supporting member can be formed. It is very advantageous to prevent deformation of the light reflecting mirror by integrally molding the mirror supporting member and the rotating shaft, or by integrally molding the mirror support member and the coil supporting member from a material having a coefficient of thermal expansion comparable to that of the light reflecting mirror.

FIG. 7 shows the actual phase delay when there is no torsional resonance or the like.

In this case, the vertical axis represents phase delay and the horizontal axis represents frequency.

The solid line shows the case where the core magnet is not solid and the magnetic flux is not very high, and the magnetic line is the case where the core magnet is solid and the magnetic flux is increased. In the case of solid, the phase delay is 180° or more. The frequency exceeded will be higher than when it is not solid.

The mirror rotation control element of the present invention can be implemented as described above, and the following effects can be obtained.

(1) Since the coil supporting member and the light reflecting mirror are coupled to each other in an almost integral configuration without using a long axis, the frequency of torsional resonance can be increased.

Therefore, a high control gain can be achieved.

(2) Since the core magnet can be made solid, the magnetic flux can be increased and high output can be obtained even if the input is low.

In other words, the high rate can be increased. (3) Since the light reflecting mirror can be provided between both bearings, the positional accuracy of the light reflecting mirror can be increased.

(4) Since a light reflecting mirror is provided between both bearings, mechanical strength can be increased and causes of vibration can be eliminated.

(5) By using the rotating shaft as a support for the light reflecting mirror, the inertial mass of the support is eliminated, and the frequency of torsional resonance can be increased.

Therefore, a high control gain can be achieved.

(6) By eliminating the support for the light reflecting mirror, the driving input can be reduced, which further leads to cost reduction.

(7) By supporting the bearing with an elastic body as shown in FIG. 4, the preload can be reduced and the backlash of the shaft can be eliminated.

Therefore, extra vibration can be eliminated.

(8) By integrally molding the support of the light reflecting mirror, the rotating shaft, and the rotating drive coil supporting member, the overall rigidity can be increased and torsional resonance etc. can be prevented.

Also, integral molding can reduce costs and further improve reliability.

(9) Preventing deformation of the light reflecting mirror due to temperature changes by forming the support of the light reflecting mirror from a material having a coefficient of thermal expansion similar to that of the light reflecting mirror, such as ferrite ceramic, glass, or other ceramics. Can be done.

Therefore, when used for control, stable control can be performed.

00) By making the core magnet solid, the magnetic flux can be increased and the effectiveness of damping can be increased.

Therefore, stability as a control element can be improved.

Furthermore, since the damping works well, the frequency at which the phase is delayed by 1800 becomes high, so that a high control gain can be achieved.

(11) By composing the coil support member with a conductive material, damping can be applied to the movement of the rotation shaft.

Thereby, the stability of the rotating device can be increased.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is a sectional view of a conventional example, FIGS. 3, 4, and 6 are sectional views of different specific examples of the present invention. 5 and 7 are characteristic diagrams. 1... Light reflecting mirror 2... Support body,
3... Rotating shaft, 4... Bearing, 5...
... Core magnet, 6 ... Case outer cylinder, 7
-...Case side plate, 8...Drive coil, 9.
... Coil support member, 10 ... Return spring, 11 ... Bearing side plate, 12 ... Elastic body, 13 ... Mirror coil support Element.

Claims (1)

[Scope of Claims] 1. A light-reflecting mirror, a support for the light-reflecting mirror, a core magnet magnetized in a direction perpendicular to the rotational axis of the light-reflecting mirror, and a core magnet that is concentric with the core magnet with a gap therebetween. a case outer cylinder that is arranged and forms a closed magnetic path; a case side plate that fixes the core magnet and the case outer cylinder in a fixed position; and a case side plate that is rotatably arranged in the gap and in a direction parallel to the axis of the core magnet. a rotational drive coil having a component, a rotational axis of the mirror, a coil support member that couples the rotational drive coil and the rotational axis of the mirror, and a return that returns the rotational drive coil to a fixed position. The core magnet is solid, one of the bearings is provided between the core magnet and the coil support member, and the other bearing is provided between the coil support member. The mirror rotation control element is provided on the opposite side of the one bearing with the light reflecting mirror interposed therebetween. 2. The mirror rotation control element according to claim 1, wherein the rotation shaft also serves as a support for the light reflecting mirror. 3. The mirror rotation control element according to claim 1 or 2, wherein the coil support member and the rotation shaft for supporting the light reflecting mirror are integrally formed. 4. The mirror rotation control element according to claim 1, wherein the coil support member is made of a conductive material. 5. The mirror rotation control element according to claim 1, wherein at least one of the two bearings of the mirror rotation shaft is attached via an elastic body. 6. The mirror rotation control element according to claim 1, wherein the support for the light reflecting mirror is made of a material having a coefficient of thermal expansion comparable to that of the light reflecting mirror.