JPH0240578Y2 - - 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 wedge attached to the other end is inserted into the palm part formed by bringing the ends into contact, and a brake oil reservoir provided on the sliding surface of the wedge that slides on the palm part is filled with oil. The present invention relates to a damper for an actuator, in which the film body and the wedge body are made to slide through a damping oil.

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. Therefore, as an improvement measure, as shown in FIG. 3, for example, filling the gap 2C of the focus drive permanent magnet 2 with viscous brake lubricant 11 using capillary action, 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 C(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 the movable part or the fixed part, and A wedge body attached to the other end is inserted into the palm part formed by bringing the other ends into contact, and a brake oil reservoir is provided on the sliding surface of the wedge body that slides on the palm part. It is an object of the present invention to solve the above-mentioned problems by causing the film body and the wedge body to slide through a brake lubricant filled in the film body and the wedge 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 wedge body, which is vertically long and tapered to protrude from the lower part of the objective lens holder 5, which is a focus moving unit that moves in the vertical direction, in the direction of the tracking moving body 8.

Reference numeral 21 denotes a brake oil reservoir, which is bored at the tip of the wedge body 20, as shown in FIG. The brake oil reservoir 21 is filled with brake oil.

Reference numeral 22 denotes a pair of brake oil scattering prevention devices, which protrude from the lower part of the objective lens holder 5 in the direction of the tracking movable body 8 so as to sandwich the wedge body 20 therebetween. By providing the brake oil scattering prevention device 22, it is possible to prevent the brake oil from scattering in the vertical direction.

Reference numeral 23 denotes a pair of elastic film members, one end of which is fixed in the vertical direction on the objective lens holder 5 side of the tracking moving body 8, which is a fixed part for vertical movement, and the other end is as follows. They touch each other to form a vertical clasp.

The distal end of the wedge body 20 is inserted into the palm-joining part of the film body 23. The tip of the wedge body 20 is
The folded palms of the film body 23 are slid in the vertical direction via the braking oil.

The wedge body 20 may be formed on the tracking moving body 8 and the film body 23 may be formed on the objective lens holder 5.

The wedge body 20, the film body 23, and the braking oil 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 made small by inserting the thin tip of the wedge body 20 into the palmar part of the film body 23 formed by elastic force, so that the viscous damping coefficient C(T) is The viscosity coefficient u(T) is not significantly affected by temperature fluctuations, and the temperature characteristics are improved.

A wedge body 30 is provided in an upwardly tapered shape at the intermediate portion of the tracking movable body 8, which is a tracking movable portion that moves in the left-right direction.

Reference numeral 31 denotes a brake oil reservoir, which is bored through both inclined surfaces 30A of the wedge body 30, as shown in FIG. The brake oil reservoir 31 is filled with brake oil.

Reference numeral 32 denotes a pair of elastic film bodies, one end of which is fixed to the base 1A of the housing 1, which is a fixed part for horizontal movement, in a direction parallel to the tracking movement direction, and the other ends are fixed to each other. The two contact each other to form a part of the palms that extend parallel to the direction of tracking movement. Width of film body 32
By increasing l ₁ as much as possible, the length l of the wedge body 30 in contact with the film body 32 is increased. Furthermore, the film body 32 is fixed so that the height w of the wedge body 30 in contact with the film body 32 is increased. The length l of the wedge body 30 is set to be longer than the width _l1 of the film body 32.

Both inclined surfaces 30A of the wedge body 30 are inserted into the joined palms of the film body 32. Both inclined surfaces 30A of the wedge body 30 are connected to the film body 3 through the braking oil.
2. Slide the palms together in the left and right direction.

Reference numeral 33 denotes a pair of brake lubricant scattering prevention devices, which move the film body 32 from the tracking moving body 8 to the wedge body 30 side.
It is extended in such a way as to sandwich it in between. By providing the brake oil scattering prevention device 33, it is possible to prevent the brake oil from scattering.

The wedge body 30 may be formed on the base 1A of the housing 1, and the film body 32 may be formed on the tracking movable body 8.

The wedge body 30, the film body 32, and the braking oil form a so-called tracking damper when the tracking movable body 8 moves in the left-right direction.

By inserting the wedge body 30 into the palm-lap portion of the film body 32 having a large width as described above, the length l in the moving direction of the moving body and the height w of the moving body can be increased, so that the viscous damping coefficient C ( T) is the viscosity coefficient u
The temperature characteristics are improved without being significantly affected by temperature fluctuations in (T).

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. The wedge body attached to the other hand is inserted into the palm-to-hand part, and the brake oil filled in the brake oil reservoir provided on the sliding surface of the wedge that slides on the palm-to-hand part is inserted. By sliding the film body and the wedge body,
The effect is that the temperature characteristics in viscous braking can be improved.

[Brief explanation of the drawing]

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... Wedge body, 21, 31... Braking oil reservoir, 22, 33... Braking oil scattering prevention device, 2
3,32...Film body.

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 a wedge attached to the other is attached to the joining part formed by bringing the other ends of the film bodies into contact. Insert the body and slide the film body and the wedge body through the braking oil filled in the braking oil reservoir provided on the sliding surface of the wedge body that slides with the palms-on part. A damper for actuators made of at least one material.