JPS63222374A - Swing arm holding part - Google Patents

Abstract

PURPOSE:To raise a ratio of rigidity in the swing direction of an arm to that in the other direction by using a belt, which is easy to assemble and does not require adjustment, and a preliminary pressure generating means to connect a support pillar and the arm. CONSTITUTION:An arm 11 can be swung in the direction of an arrow 32, and a belt 13 functions as a pole or beam element in two translation directions along the belt surface in the contacting part, where the suppart pillar 1 and the arm 11 are brought into contact with each other with the belt 13 between them, and the rotation direction in a plane along the belt surface, and high rigidity determined by the shape and the material constant is attained in these directions. With respect to one translation direction and one rotation direction related to contacting part separation direction, the rigidity is very high in the contacting part approaching direction but is low in the contacting part separation direction if the arm is held by only the belt 13, however, a preliminary pressure is applied in the contacting part close-contacting direction by the preliminary pressure generating means, and thus, sufficient rigidity is attained in these directions.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an arm holder of a lens actuator of an optical head that records, reproduces, and erases information on the surface of a recording medium using optical means. The present invention relates to a swing arm holding section that swingably holds the swing arm.

[Conventional technology]

Conventionally, a laser beam is used as a light source, and this laser beam is modulated with a pulsed signal from an external information source to record information in binary form on the surface of a recording medium, or to reproduce information that has already been recorded. Alternatively, in an optical head for erasing, in order to accurately record, reproduce, or erase information, a lens actuator is used to control the focusing direction so that the focus position of the condensing lens is always on the surface of the recording medium. In other words, the position of the condensing lens in the optical axis direction is controlled, and the light spot of the focused laser beam on the recording medium surface is accurately aligned with the guide groove formed in advance on the recording medium. Tracking position control is performed by driving the condensing lens in a tracking direction perpendicular to the guide groove so that the position is determined.

As these drive means, electromagnetic drive means consisting of a magnetic circuit and a coil are generally used, and as a method of supporting the movable part, in the focusing direction, two sets of movable parts each carrying a condenser lens are used. In the tracking direction, the movable part on which the condenser lens is mounted, two sets of parallel plate springs, and an arm serving as the base of the other end of the two sets of parallel plate springs are integrated. A method has been proposed in which the optical head is rotated around a point on the optical head housing as the center of rotation. For example, this is shown in Japanese Patent Application No. 199504/1983 filed by the same applicant as the present invention.

[Problem that the invention seeks to solve]

A conventional swing arm holding section that holds an arm so that the movable section can swing uses a bearing such as a small-diameter radial ball bearing or a pivot ball bearing. However, although these methods of supporting the rotating shaft using bearings are effective in obtaining good frequency characteristics of the actuator, assembly and adjustment are complicated. Therefore, if the rotation support part can be replaced with another simpler means, there will be a great advantage in terms of the number of parts, assembly and adjustment man-hours, etc. However, if we try to do this with a single leaf spring, for example, in order to set the rigidity of the temporary spring in the torsional direction to be sufficiently high compared to the rigidity of the leaf spring in the direction of easy bending, which corresponds to the swing direction of the arm. It is necessary to make the width of the temporary spring very wide, which is not practical at all. Furthermore, if a leaf spring with a width that does not cause any problem in practical use is used, the ratio of the stiffness in the two directions described above cannot be made large, and the actuator has the disadvantage that the characteristics in the high range deteriorate.

In addition, by using multiple leaf springs in combination, this
Although the ratio of the stiffnesses in the two directions can be somewhat increased, it is not easy to improve it to a sufficient degree for practical use.

It is an object of the present invention to provide a swing arm holder that eliminates such drawbacks, is easy to assemble, does not require adjustment, and has a large ratio of rigidity in the swinging direction of the arm and in other directions. It is in.

[Means for solving problems]

The present invention provides a swing arm holding section that holds an arm on a fixed member so as to be able to swing freely within one operating plane, wherein at least a portion of a substantially cylindrical curved surface whose axis is perpendicular to the operating plane is a convex curved surface; a support column fixed on a fixed member; a belt that holds the arm to the support column with a surface of the arm facing the convex curved surface of the support column; and a belt that presses the arm toward the support column. and a preload generating means for generating preload, and the belt applies tension along the surface of the arm and the convex curved surface of the support column at a portion where the surface of the arm and the convex curved surface of the support column face each other. The arm is attached to the arm and the support column so as to intersect with each other.

[Effect]

According to the swing arm holding portion of the present invention, basically the rigidity in the swinging direction, that is, the restoring force is extremely small.

This is because the restoring forces of the belt parts on both sides of the intersection of the belts, which are the main forces of the restoring force, cancel each other out, and the belt deflects along the contact surface, so each restoring force is not affected by the swing angle of the arm. This is because the force is constant.

On the other hand, regarding the two translational directions along the belt surface and the in-plane rotational direction along the belt surface at the contact point where the support column and the arm are in contact via the belt, the belt acts as an element of the column or girder. It has a high stiffness determined by its shape and material constants. In addition, in other directions, i.e. one translational direction and one rotational direction related to the direction in which the contact parts leave, if only a belt is used, the rigidity is very high in the direction in which the contact parts come closer together, but in the direction in which the contact parts leave. Although the rigidity is low, since preload is applied by the preload generating means in the direction of bringing the contact portions into close contact, it has sufficient rigidity in these directions as well.

Therefore, it is possible to realize a swing arm holder with a large ratio of rigidity between the arm swing direction and other directions, and it can be assembled by simply attaching a belt to two parts, and no adjustment is required. Become.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG.
The figure is z in the xyz axis coordinate system shown in Figure 1.
FIG. 3 is a plan view viewed from an axial force. In this swing arm holding part, the support column 1 has a cylindrical curved surface whose central axis is perpendicular to a plane including the It is fixed to the fixing member 3 of the door actuator housing.The support column l has belt attachment parts 4a, 4b consisting of edges on both sides thereof.The arm 11 is a flat arm having a flat surface 12.16. is arranged so that the plane 12 faces the convex curved surface 2 of the support column 1, and is connected to the support column l by a bell) 13.

Belt 13 is shown in FIG. Figure 3(a) shows belt 1
FIG. 3(b) is a side view of a state in which the device 3 is unfolded, and FIG. 3(b) is a plan view thereof. The belt 13 has three elongated belt parts 5, 6.
7 and a belt central portion 8. Belt narrow part 5
extends in one direction from belt central portion 8, and belt strips 6 and 7 extend in the other direction. The width l of the belt elongated portion 5 is
It shall be smaller than the distance between the belt elongated parts 6 and 7. This is so that when the belt 13 is wound as will be described later, the belt elongated portion 5 will fit between the belt elongated portions 6 and 7 at the intersection. Belt narrow part 5
．． One end of 6.7 is integrated at the belt center part 8, and a reinforcing plate 9 is provided at the other end of the belt elongated portion 5, and a reinforcing plate 10 is provided at the other end of the belt elongated portions 6 and 7. Pasted together, each constitutes a hook.

With such a belt 13, the arm 1 is connected as follows.
1 and the support column 1 are connected. That is, the belt central portion 8 of the belt 13 is located on the plane 16 opposite to the plane 12 of the arm 11, and the belt elongated portions 5 and 6°7 are placed on the plane 12.
The belt is wound with tension on the side, crossed so that the belt elongated part 5 is between the belt elongated parts 6 and 7, and then wound with tension along the convex curved surface 2 of the support column l to make the belt elongated. The reinforcing plate 931O constituting the hook attached to the end of the support column 1 is attached by hanging it on the belt attachment parts 4a and 4b of the support column 1. In this case, by setting the length of the belt 13 to be shorter than the length of the arm 11 and the portion of the support column 1 along which the belt 4 runs, tension can be easily applied only by attachment. By attaching the belt 13 with tension in a figure 8 shape in this way, the plane 1 of the arm 11
2 and the convex curved surface 2 come into close contact with each other through the belt at the intersection of the belt 13. As mentioned above, the elongated parts 6 and 7 of the belt 13 are arranged to sandwich the elongated part 5, which means that when the belt 13 is tightly wound around the arm 11 and the support column 1, the belt 1 This is to prevent twisting and interference at the intersection of -13.

The swing arm holding portion of this embodiment further has one end attached to a structure 14 fixed to the fixing member 3 as a preload generating means for generating preload at the close contact portion between the arm 11 and the support column 1 via the belt 13. The elastic body 15 is connected to the elastic body 15. This elastic body 15 comes into contact with the opposite end of the arm 11 in a compressed state at a position of a plane 16 corresponding to substantially the back side of the contact portion, and generates a preload in the contact portion.

With the above configuration, the arm 11 is connected to the arrow 32 in FIG.
It becomes possible to move in the direction shown by . on the other hand,
Regarding the two translational directions along the belt surface and the in-plane rotational direction along the belt surface of the contact portion (close contact portion) where the support column 1 and the arm 11 contact via the belt 13, the belt is a pillar or a girder. It has high rigidity determined by its shape and material constants. In addition, one translation direction related to a direction other than this, that is, the direction in which the contact part separates, and one
Regarding the two rotational directions, holding by the belt 13 alone has very high rigidity in the direction in which the contact parts come closer together, but has low rigidity in the direction in which they move away from each other. Therefore, it has sufficient rigidity in these directions as well.

Next, a case will be described in which the swing arm holder according to the present invention is mounted. FIG. 4 is an exploded perspective view of the lens actuator. In this lens actuator, one end portions of four leaf springs 21, 22, 23, and 24 are connected to the arm 11 of the swing arm holding portion shown in FIG. 4 leaf springs 21, 22, 23,
The other end of 24 is connected to a movable part 29 . Movable part 2
9 is a condenser lens 25. Tiger.

King Koil 27. It consists of a focusing coil 28 and further has gaps 26a and 26b.

On the other hand, the lens actuator housing 34, which is a fixed member, has yokes 30, 31, 32, and 33 that form a magnetic circuit.
is installed. An elastic body 15 is attached to the yoke 30 and serves as a preload generating means for the swing arm holding portion.

The assembled lens actuator is shown in a perspective view in FIG. The yoke 32 is inserted into the gap 26a shown in FIG. 4, and the yoke 31 is inserted into the gap 26b.

The support column 1 is fixed to the lens actuator housing 34.

The elastic body 15 comes into contact in a compressed state at a position substantially on the back side of the contact portion between the support column 1 and the arm 11, and generates a preload in the contact portion.

According to the above configuration, the movable part 29 includes the focusing coil 28. A tracking coil 27 is attached,
Driving forces in the Z direction and the X direction are generated by interaction between these coils and the magnetic circuit.

Therefore, the arm 11 of the swing arm holder is
The X-direction movable portion 29. It becomes possible to swing the temporary springs 21 to 24 together. In this case, even if the direction in which the arm 11 swings in contact with the support column 1 is indicated by an arrow 32), the belt 13 bends along the convex curved surface of the cylinder of the support column 1, so the long and narrow belts on both sides intersect with each other. The restoring forces of each part are always the same and opposite in magnitude and cancel each other out. On the other hand, in the direction along the belt surface at the contact portion, the belt 13 acts as a pillar or girder element and has high rigidity to restrict movement in this direction. In addition, in other directions than these, that is, in the direction in which the contact portion separates, the movement in this direction is restricted by high rigidity corresponding to the preload obtained by the preload generating means described above.

Therefore, according to this embodiment, while the stiffness in the swinging direction is small due to only the restoring force in the swinging direction by the elastic body 15 of the preload generating means, the stiffness in other directions can be set high. , it is possible to realize a swing arm holding portion that has a large ratio of the rigidity of the two, is easily assembled, and does not require adjustment.

In the above embodiment, the elastic body 15 constituting the preload generating means is
is connected between the structure 14 (corresponding to the yoke 30 in FIG. 4) and the arm 11, but if the upper part of the support column 1 protrudes toward the arm ll side, the support column 1 and the arm 11.

Next, other embodiments of the present invention will be described.

FIG. 6(a) is a plan view showing another embodiment of the present invention, and FIG. 6(b) is an elevational sectional view of FIG. 6(a). In this swing arm holder, a support column 41 and an arm 42 are connected via a belt 43, similar to the embodiment shown in FIG. This is the same as the embodiment shown in FIG.

The preload generating means in this embodiment differs from the embodiment shown in FIG. 1 in that a support column 41 and an arm 42 constitute a magnetic circuit, and a preload is generated by the attraction force generated by the magnetic force.

That is, the arm 42 is made of a ferromagnetic material, and the support column 41 is made of a ferromagnetic material.
A magnet that has a back yoke 44 on the surface opposite to the contact portion shown by 51, the lower layer 46 and the upper layer 45 are magnetized in opposite directions in two directions, and is magnetized in the direction from the arm 42 to the back yoke 44. It consists of As a result, the magnet lower layer 46. Back yoke 44. Magnet upper layer 45. A closed magnetic path is formed that goes around the arm 42 in order, and the arm 42 is connected to the support column 4.
A preload is generated that strongly attracts the In this case, the magnetic resistance between the arm 42 and the support column 41 hardly changes even if the arm 42 swings or moves, and the strength of the attractive force hardly changes. Further, the direction in which the force is generated is also approximately perpendicular to the contact portion, and as a result, the preload generating means generates almost no restoring force in the arm swinging direction.

Therefore, according to this embodiment, while the stiffness in the swinging direction is small and almost zero, the stiffness in other directions can be set high, and the ratio of the two stiffnesses is large, and It is possible to realize a swing arm holder that can be easily assembled and does not require adjustment.

Two embodiments have been described above, but in both embodiments, the belt can be easily fixed to the arm with an adhesive or the like at an appropriate position, and the arm, support column, By providing steps and protrusions on the belt, positioning during assembly can be easily performed. Furthermore, although the surface of the support column that contacts the arm is a convex curved surface made of a part of a cylinder, it is not limited to this, and may be a convex curved surface made of a part of a substantially cylinder.

Conversely, the surface of the arm that contacts the support column is a plane, but the surface of the arm that contacts the support column is not limited to this, for example, it may be approximately cylindrical with an axis perpendicular to the plane of motion. It is also possible to use a contact surface consisting of a portion of a convex curved surface.

〔Effect of the invention〕

In the present invention, since the support column and the arm are connected by a belt that is easy to assemble and does not require adjustment, and by a preload generating means, the ratio of the rigidity of arm holding in the swinging direction of the arm and in other directions is This has the effect of making it sufficiently large.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing an embodiment of the present invention.
FIG. 1 is a plan view, FIG. 3 is a diagram showing a belt, FIG. 4 is an exploded perspective view of a lens actuator, FIG. 5 is a perspective view of a lens actuator, and FIG. 6 is a diagram showing another example of the present invention. It is a figure showing an example. ■, 41...Support column 2...Convex curved surface 3...Fixing members 4a, 4b...Belt attachment part 5.6.7...Belt elongated part 8... ...Belt central part 9.10...Reinforcement plates 11, 42...Arm 12) 16)...Planes 13, 43...Belt 14...Structure 15... ...Elastic body 44...Back yoke 45...Upper layer 46...Lower agent Patent attorney Yoshiyuki Iwasa! Fig. 1 (a) 11 arms Fig. 4 Fig. 5 42 arm support columns (a) (b) Fig. 6 Single yoke

Claims (4)

[Claims] (1) In a swing arm holding part that holds the arm on a fixed member so as to be able to swing freely within one operating plane, the shaft has at least a part of a substantially cylindrical curved surface perpendicular to the operating plane as a convex curved surface, and a support column fixed on a member; a belt that holds the arm to the support column with the surface of the arm facing the convex curved surface of the support column; and a preload that presses the arm toward the support column. and a preload generating means for generating a preload, wherein the belt applies tension along the surface of the arm and the convex curved surface of the support column at a portion where the surface of the arm faces the convex curved surface of the support column. A swing arm holder, wherein the swing arm holder is attached to the arm and the support column so as to cross each other. (2) In the swing arm holder according to claim 1, the surface of the arm that contacts the convex curved surface of the support column via the belt is a flat surface, or the axis thereof is perpendicular to the operating plane. A swing arm holder characterized by having a convex curved surface forming at least a part of a substantially cylindrical curved surface. (3) In the swing arm holder according to claim 1 or 2, the preload generating means is configured to generate contact pressure between the arm and the support column using an elastic body. Features a swing arm holder. (4) In the swing arm holding section according to claim 1 or 2, the preload generating means is such that at least a portion of the arm is made of a ferromagnetic material, and at least a portion of the support column is made of a magnet. A swing arm holder comprising: a magnetic circuit formed by the arm and the support column to generate contact pressure between the arm and the support column.