JP3458922B2 - Voice coil type linear motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice coil for a small stroke in which a permanent magnet is used as a magnetic field and a flat coil is inserted through a gap between the magnetic fields. Related to linear motors. As a conventional technique, a pair of yokes are opposed to each other, and permanent magnets are arranged at a predetermined pole pitch so that the polarities of magnetic poles adjacent to the opposing surfaces of the yokes are alternately different. It has a field part of a linear motor in which the length of the permanent magnets at both ends is half the length of the other permanent magnets, and an armature part in which coreless flat multi-phase coils are arranged in the permanent magnet arrangement direction. There is a linear motor that alternately excites phase coils and moves an armature portion (for example, see Japanese Patent Application Laid-Open No. 57-1134).
No. 65). Although not disclosed in the prior art, in order to alternately excite the multi-phase coils and to propel the armature, the arrangement of the multi-phase coils is permanent. It is customary to have a phase of 1 / phase number of the pole pitch of the magnet. In this case, the armature moves at the pole pitch of the permanent magnet. Therefore, for example, when only one minute movement in the order of micron order is required, the pole pitch of the permanent magnet is changed to the micron order. In addition, it is necessary to arrange the multi-phase coils in the number of 1 / phase, which requires ultra-precision processing, which is very difficult in manufacturing. Therefore,
SUMMARY OF THE INVENTION An object of the present invention is to provide a linear motor that is easy to manufacture and is suitable for one-shot minute movement only in the front-rear direction. In order to solve the above-mentioned problems, the present invention provides a method in which a pair of yokes are opposed to each other, and a central permanent magnet is provided on each of opposing surfaces of the yokes. The field part in which the polarities of the adjacent and opposed magnetic poles are alternately exchanged at both ends of the armature part, and end permanent magnets having a half length of the central permanent magnet are arranged at a predetermined pole pitch Pm in the moving direction of the armature part. And an armature portion in which end coils are disposed at both ends of the center coil at a predetermined pole pitch Pc in the moving direction between the opposing surfaces of the center permanent magnet and the end permanent magnet with a gap therebetween. In the above voice coil type linear motor, the phase δ of the pole pitch Pm of the permanent magnet and the pole pitch Pc of the coil is δ = | Pm−Pc | (where δ <Pm
/ 2) and means for variably adjusting the phase.
The means for variably adjusting δ is a hole for accommodating the center coil.
And a bobbin and shim with end grooves to accommodate the end coils.
Have By the above means, the pole pitch Pm of the permanent magnet and the pole pitch Pc of the coil are shifted by the phase δ. Embodiments of the present invention will be described below with reference to FIG. A central permanent magnet 11 is disposed on each of the opposing surfaces of the pair of yokes 1 facing in parallel with the moving direction, and the polarities of the adjacent and opposing ones are alternately switched at both ends of the central permanent magnet 11 to reduce the length. Half end permanent magnets 12 of the center permanent magnet 11 are arranged such that the center permanent magnet 11 and the end permanent magnets 12 have a pole pitch Pm. The yoke 1, the central permanent magnet 11 and the end permanent magnet 12 constitute a field portion F. Central permanent magnet 11 and end permanent magnet 12
A flat rectangular concentrated winding coil 2 is supported by a bearing (not shown) in the space between the coils facing each other so as to be movable in the traveling direction of the armature portion A. When the phase δ is set to a value less than the pole pitch Pm / 2, the coil 2
, The end coil 22 is arranged so that the phase δ can be adjusted at a pole pitch (Pm + δ), and the center coil 21 and the end coil 22 are connected in series. That is, the pole pitch Pm between the center permanent magnet 11 and the end permanent magnet 12 and the pole pitch between the center coil 21 and the end coil 22 are shifted by the phase δ. The ampere turns of the center coil 21 and the end coil 22 are substantially equal. Center coil 21
And the end coil 22 constitute the armature portion A. The operation will be described below. Center coil 21
When + and-are alternately supplied to the end coil 22 and a direct current is supplied, the armature portion A is brought into phase δ by electromagnetic action with the field portion.
Swing back and forth by (equivalent to stroke). FIG. 2 shows a second embodiment. In this example, the phase δ is adjusted. The rectangular bobbin 3 made of a non-magnetic material is provided with a central hole 31 for tightly storing the central coil 21, and an end groove 32 for storing the end coil 22 so that the end coil 22 can be moved right and left on both sides thereof. The end coil 22 is housed in the end groove 32, and the shim 4 is inserted between the end face of the end coil 22 and the end face of the end groove 32 on the side of the center hole 31. The pole center of the coil 22 is adjusted, and the end coil 22 and the shim 4 are fixed to the bobbin 3 by bonding or the like. At this time, since the pole center distance Pc is the pole pitch of the coil, Pc−Pm = δ, and the phase δ is variably adjusted. The phase δ can be adjusted by placing the center coil 21 and the end coil 22 in the mold shape at the pole pitch (Pm
+ Δ), and the bobbin may be molded with resin. In this case, the phase δ is fixedly adjusted. In addition,
In the description, the pole pitch Pc between the center coil and the end coil is shifted by the phase δ between the center permanent magnet and the end permanent magnet pole pitch Pm, but conversely, the pole pitch between the center coil and the end coil is changed. On the basis of the pitch Pc, the pole pitch Pm of the central permanent magnet 11 and the end permanent magnet 12 is Pm = (Pc−δ).
So that the center permanent magnet 11 and the end permanent magnet 12
A nonmagnetic spacer may be interposed therebetween. According to the above configuration, the following effects can be obtained. (1) Since the adjustment of the phase δ is performed only with the pole pitch Pc of the coil or the pole pitch Pm of the permanent magnet, ultra-precision processing for ensuring the pitch accuracy is not required, and the manufacture is facilitated. (2) The stroke can be easily changed by adjusting the phase δ.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front sectional view showing an embodiment of the present invention. FIG. 2 is a front sectional view showing a second embodiment of the present invention, and FIG. Description: 1 Yoke 11 Central permanent magnet 12 End permanent magnet 2 Coil 21 Central coil 22 End coil 3 Bobbin 31 Center hole 32 End groove 4 Shim A Armature section F Field section

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-131967 (JP, A) JP-A-3-243161 (JP, A) JP-A-5-284722 (JP, A) 159582 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H02K 33/18, 41/06 G11B 21/02

Claims (1)

(57) Claims 1. A pair of yokes are opposed to each other, and a central permanent magnet is provided on each of opposing surfaces of each yoke. The field part in which the polarity is alternately changed, and end permanent magnets having a half length of the central permanent magnet are arranged at a predetermined pole pitch Pm in the moving direction of the armature part; A voice coil type linear motor provided with an armature portion in which end coils are disposed at opposite ends of a central coil at predetermined pole pitches Pc in the moving direction between gaps between opposed surfaces of the permanent magnets. The pole pitch Pm of the magnet and the pole pitch P of the coil
phase of c = | Pm-Pc | (where δ <Pm / 2)
Means for variably adjusting the phase δ.
The means for strangely adjusting are a hole for accommodating the center coil and an end.
With bobbin and shim with end groove to accommodate external coil
Voice coil type linear motor
Ta.