JPH02197248A - Voice coil motor magnetic circuit - Google Patents

Abstract

PURPOSE:To make the gap dimensions of a magnetic circuit highly accurate and to facilitate assembling of said circuit to reduce the manufacturing cost thereof by combining the combining holes of two flat-plate back yokes, to which magnets are joined respectively, with the internal hole of a pipe-shaped spacer through a shaft. CONSTITUTION:A shaft 4 passes through the internal hole of a spacer 3 and back yokes 2. Said shaft 4 is fixed to said back yokes 2 by such means as adhesion, welding, and press fit and assembled into an apparatus. Permanent magnets 1 are fixed to the back yokes 2 by adhesion, etc. Said back yokes 2, spacer 3 and shaft 4 are made by the use of soft magnetic material such as pure iron. As the back yokes 2 are shaped into flat plates, they are easy to process, and both spacer 3 and shaft 4 have a simple shape so that a sufficient processing accuracy can be secured at a low cost.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is directed to a voice coil motor (hereinafter referred to as VCM).
e Co11 Motor) related to magnetic circuits.

[Prior Art] Conventionally, a VCM magnetic circuit has a structure in which a magnet 6 is fixed to a yoke 5 in which the magnetic circuit is integrated, as shown in FIG. A structure in which the shafts are connected by an attached shaft 8 has been known.

[Problem to be solved by the invention] However, with the above-mentioned conventional technology, machining to control the gap dimensions of the VCM magnetic circuit with high precision takes time and effort, and it is difficult to obtain sufficient machining accuracy in a short period of time. .

Therefore, if the machining is completed in a short time with the aim of reducing costs, the gap dimensions of the VCM magnetic circuit will vary and the magnetic properties of the gap will not be stable.If the machining precision is increased with the aim of stabilizing the magnetic properties, the machining time will increase and the cost will increase. was a problem.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and it is an object of the present invention to provide a VCM magnetic circuit having a structure that allows the gap size of the magnetic circuit to be easily managed accurately.

[Means for Solving the Problems] In the voice coil motor magnetic circuit of the present invention, in the voice coil motor magnetic circuit using permanent magnets, two flat back yokes to which magnets are joined are arranged in a no-V shape. The spacer and the spacer! The inner hole of the back yoke is coupled to the back yoke by a shaft passing through the coupling hole of the back yoke.

[Example] The present invention will be described and explained in detail below based on examples.

FIG. 1 is a main configuration diagram of a VCM magnetic circuit showing an embodiment of the present invention, (a) is a front view, (b) is a side view, (
C) is a cross-sectional view, where 1 is a permanent magnet, 2 is a back yoke, and 3
is the spacer 4 is the shaft, and the shaft passes through the inner hole of the spacer and the back yoke. Here, the shaft is fixed to the back yoke by adhesive, welding, press-fitting, or the like, and if necessary, the spacer is also fixed by the same means and assembled. The permanent magnet is magnetized in the direction shown by the arrow in the figure, and is fixed to the back yoke by adhesive or the like. The back yoke and spacer shaft are made of soft magnetic materials such as pure iron.

In the VCM magnetic circuit of this embodiment, since the back yoke is flat, it is easy to process, and the spacer shaft has a simple shape, allowing sufficient processing accuracy to be achieved at low cost.

[Effects of the Invention] As described above, according to the present invention, the following effects are produced: (a) Since the magnetic circuit component has a simple shape, it is easy to process, has small dimensional variations, and can reduce manufacturing costs. .

(b) Since the length dimension of the spacer is easy to control, the gap dimension of the magnetic circuit can be controlled with high precision, and the magnetic characteristics of the gap of the VCM magnetic circuit are constant.

(C) Assembly is easy because no parts such as screws are used for assembly.

[Brief explanation of the drawing]

FIG. 1 shows (a) a front view (b) of the VCM magnetic circuit of the present invention.
) is a side view and (c) is a cross-sectional view. Figure 2 is a structural diagram of a conventional VCM magnetic circuit. FIG. 3 is a structural diagram of a conventional VCM magnetic circuit. Applicant Seiko Epson Co., Ltd. Representative Patent Attorney Kizobe Suzuki 1 person (G) Figure 1 = 313

Claims (1)

[Claims] In a voice coil motor magnetic circuit using permanent magnets, two flat back yokes to which magnets are joined are connected by a pipe-shaped spacer and a shaft that passes through the inner hole of the spacer and the coupling hole of the back yoke. A voice coil motor magnetic circuit characterized by: