JPH0240577Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a damper for an actuator, and in particular, one end of a pair of elastic film bodies is fixed to either a moving part or a fixed part, and the other end of the film body is fixed to either a moving part or a fixed part. A double-edged member attached to the other end is inserted into the joining part formed by bringing the ends into contact, and the braking oil filled in the part where the joining part and the double-edged member slide is applied. The present invention relates to a damper for an actuator in which the film body and the double-edged body are made to slide.

Taking an actuator, for example, an optical pickup actuator for a video/audio disc player, as an example, elastic support of the actuator will be explained with reference to FIG.

The elastic support has a longitudinal direction parallel to the tracking movement direction (X-axis direction) and is attached to the base 1A of the housing 1.
A pair of square rod-shaped focus drive permanent magnets 2 consisting of a permanent magnet piece 2A and a magnetic piece 2B fixed to
A rectangular focus control coil 3 is disposed in the cavity 2C and is provided around the objective lens 4.
is arranged in the gap 6A between the other end of the objective lens holder 5 attached to the center and a pair of tracking drive permanent magnets 6 whose longitudinal direction is parallel to the tracking movement direction and fixed to the base 1A of the housing 1. The objective lens holder 5 can be moved vertically by a parallel plate spring 9 for focusing, which is installed on the upper and lower surfaces of the other end of the tracking moving body 8, around which a rectangular coil 7 for tracking control is wound. It is elastically supported by a tracking parallel plate spring 10 whose central part is fixed to the side walls at both ends of the tracking movable body 8, and whose both ends are fixed to both side walls 1B parallel to the tracking movement direction of the housing 1. This is done by elastically supporting the objective lens holder 5 freely in the left-right direction via the focus parallel plate spring 9.

When metal plate springs are used as the focusing parallel plate spring 9 and the tracking parallel plate spring 10, which are the elastic supports of the actuator, if braking is not applied, the resonance peak will be large as shown by the solid line in Figure 2. Therefore, the fact that this resonance peak is large itself makes it difficult to control when the resonance peak frequency and resonance peak value change due to temperature change or the like. As a countermeasure to this problem, for example, as shown in FIG. 3, filling the gap 2C of the focus drive permanent magnet 2 with viscous brake lubricant 11 using capillarity. There is scattering of the brake lubricating oil 11, poor temperature characteristics, instability, and durability problems.

In addition, when viscous damping the resonance peak by a metal plate spring, the viscous damping coefficient C due to temperature T fluctuation
(T) is expressed as C(T)∝u(T)・l・w/g. Here, u(T) is the viscosity coefficient, l is the length of the moving body in the moving direction in the viscous body, w is the height of the moving body, and g is the distance between the viscous body and the side wall that holds the moving body, i.e. This is the gap length (see Figure 1).

In order to make the viscosity coefficient u(T), which influences the temperature characteristics of the viscous damping coefficient C(T), as negligible as possible, the shape effects l, w, and g should be improved. Here, by increasing l and w or decreasing g, the influence of temperature fluctuations on the viscosity coefficient u(T) can be reduced.

This invention was made by focusing on the problems of the prior art, and involves fixing one end of a pair of elastic film bodies to either a movable part or a fixed part, and A double-edged body attached to the other end is inserted into the palm part formed by bringing the other ends into contact, and a braking lubricant is filled in the part where the palm part and the double-edged body slide. It is an object of the present invention to solve the above-mentioned problems by causing the film body and the double-edged body to slide through the film body and the double-edged body.

This invention will be explained below based on the drawings.

FIG. 4 is a schematic exploded perspective view of an actuator for an optical pickup to which this invention is applied.

Reference numeral 20 denotes a pair of elastic film bodies, one end of which is fixed in the vertical direction to the side surface of the lower tracking movable body 8 side of the objective lens holder 5, which is a focus moving part that moves in the vertical direction. The other ends are in contact with each other to form a vertical palm part.

Reference numeral 21 denotes a pair of brake oil scattering prevention devices, which protrude laterally from the side surface of the lower part of the objective lens holder 5 on the side of the tracking moving body 8 to sandwich the film body 20, as shown in FIG. ing.

Reference numeral 22 denotes a double-edged member, which projects vertically from the objective lens holder 5 side of the tracking movable body 8, which is a fixed portion for vertical movement, toward the objective lens holder 5.

The tip of the double-edged body 22 is inserted into the palm-joining part of the film body 20. A portion where the palms of the film body 20 slide against the double-edged body 22 is filled with a braking lubricant 23 using capillary action. And the palm part of the film body 20 has a brake lubricant 23.
The double-edged body 22 is slid in the vertical direction via the . The scattering of the braking oil 23 in the vertical direction is prevented by providing the braking oil scattering prevention device 21.

The film body 20 may be formed on the tracking moving body 8, and the double-edged body 22 may be formed on the objective lens holder 5.

The film body 20, the double-edged body 22, and the braking oil 23 form a so-called focus damper when the objective lens holder 5 moves in the vertical direction.

In this way, the gap length g can be reduced by inserting the tip of the thin double-edged body 22 into the palmar part of the film body 20 formed by elastic force, so the viscous damping coefficient C(T) is Viscosity coefficient u(T)
temperature characteristics are improved without being significantly affected by temperature fluctuations.

Reference numeral 30 denotes a pair of elastic film members, one end of which is fixed in a direction parallel to the tracking movement direction to the lower surface of the intermediate portion of the tracking moving body 8, which is a tracking movement unit that moves in the left-right direction. The other end portions contact each other to form a palm-joining portion in a direction parallel to the tracking movement direction.

Reference numeral 31 denotes a pair of brake oil scattering prevention devices, which extend from the lower surface of the intermediate portion of the tracking moving body 8 in a direction perpendicular to the tracking movement direction, as shown in FIG.
It protrudes downward to sandwich the film body 30.

Reference numeral 32 denotes a double-edged member, which projects upward from the base 1A of the housing 1, which is a fixed portion for movement in the left-right direction, in a direction parallel to the tracking movement direction. The length l ₁ of the double-edged body 32 is made as large as possible, and the length l of the film body 30 is made large. Note that the length l of the film body 30 is set to be longer than the length _l1 of the double-edged body 32. Furthermore, the palm-closing portion of the film body 30 is formed so as to increase the height w of the palm-clasping portion of the film body 30 that contacts the double-edged body 32.

The double-edged body 32 is inserted into the joined palm portion of the film body 30.

A portion where the palms of the film body 30 slide against the double-edged body 32 is filled with a braking lubricant 33 using capillary action. And film body 3
0 slides on the double-edged body 32 in the left-right direction via the braking oil 33.

Splashing of the brake oil 33 in the left-right direction is prevented by the brake oil scattering prevention device 31.

Place the film body 30 on the base 1A of the housing 1.
Alternatively, the double-edged body 32 may be formed on the tracking moving body 8.

The film body 30, the double-edged body 32, and the braking oil 33 move the tracking moving body 8 in the left and right direction.
A so-called tracking damper is formed when the movement of the damper occurs.

By inserting the double-edged body 32 into the palm-lap portion of the film body 30 having a large length as described above, the length l in the moving direction of the movable body and the height w of the movable body can be increased, so that the viscous damping coefficient can be increased. C(T) is not greatly affected by temperature fluctuations in the viscosity coefficient u(T), and the temperature characteristics are improved.

As explained above, this invention is formed by fixing one end of a pair of elastic film bodies to either the movable part or the fixed part, and bringing the other ends of the film bodies into contact with each other. Insert the double-edged body attached to the other hand into the palm part, and the film body and the double-edged body By making the body slide, an effect can be obtained in that the temperature characteristics in viscous braking can be improved.

[Brief explanation of drawings]

Fig. 1 is a schematic exploded perspective view of the actuator of a conventional optical pickup, Fig. 2 is a diagram showing the relationship between frequency and gain, Fig. 3 is a diagram with brake oil filled in the gap, and Fig. 4 5 is a schematic exploded perspective view of an actuator for an optical pickup to which this invention is applied, FIG. 5 is a detailed view of a focus damper, and FIG. 6 is a detailed view of a tracking damper. 1... Housing, 2... Permanent magnet for focus drive, 3... Square coil for focus control, 4
...Objective lens, 5...Objective lens holder, 6...
... Permanent magnet for tracking drive, 7 ... Rectangular coil for tracking control, 8 ... Tracking moving body, 9 ... Parallel leaf spring for focusing, 10 ... Parallel leaf spring for tracking, 11 ... Lubricating oil for braking,
20, 30... Film body, 21, 31... Braking oil scattering prevention device, 22, 32... Double-edged body, 2
3,33...braking oil.

Claims (1)

[Scope of utility model registration request] One end of a pair of elastic film bodies is fixed to either the movable part or the fixed part, and the other end of the film bodies is brought into contact with each other. A damper for an actuator, in which a film member is inserted and the film member and the double-edged member are made to slide through a damping oil filled in a portion where the palms-together part and the double-edged member slide.