JP2003134791A - Permanent magnet synchronous linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permanent magnet synchronous linear motor capable of easily reducing a cogging thrust even if the shape dimension of an actual motor or the real magnetic characteristics of a magnetic member are deviated from designing values. SOLUTION: The permanent magnet synchronous linear motor comprises a first field 1 having a plurality of permanent magnets 12 alternatively having different polarities and aligned linearly on a first field yoke 31a, and a first armature 32 disposed oppositely to the field 1 via a magnetic air gap. The armature 32 has a first armature core 21 having main teeth 21b and a slots 21a, and a first armature winding 22 winding a coil in the slot 21a of the ore 21. A first armature 2 has a vibration force generating means 3 for generating a vibration force in the same period as that of the cogging thrust, so as to cancel the cogging thrust changing in association with the first armature 2 relatively moving to the opposite side to the side opposed to the first field 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet type synchronous linear motor used in a transportation system for FA equipment, such as a table feed of a machine tool or a stepper drive mechanism of a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art Conventionally, a permanent magnet type synchronous linear motor used in a transportation system of FA equipment, for example, a table feed of a machine tool or a stepper drive mechanism of a semiconductor manufacturing apparatus is shown in FIG. FIG. 4 is a side sectional view of a conventional permanent magnet type synchronous linear motor. This linear motor has a basic configuration of 8 poles and 9 slots,
An example will be described in which the field 1 is used as a stator for the mover that relatively moves the armature 2. In the figure, 1 is a field, 11 is a flat field yoke, 12 is a permanent magnet attached to the field yoke 11 so as to have different polarities alternately, 2 is a permanent magnet 12 and a magnetic gap. And 21 are armature cores facing each other, and are armature cores, which are main teeth 21b for punching an electromagnetic steel plate in a comb-teeth shape to form slots 21a and main teeth 2
Steel plates having a yoke portion 24 connecting 1b are laminated and fixed. Reference numeral 22 is an armature winding wound around the slot 21a. Reference numeral 23 denotes auxiliary teeth provided at both ends of the armature core 21, which are provided with means for reducing the cogging thrust generated by the end effect of both ends of the armature core.

FIG. 5 is a diagram showing a cogging thrust waveform of a conventional permanent magnet type synchronous linear motor. Based on the condition that the cogging thrust F1 acting on the main teeth 21b and the cogging thrust F2 acting on the auxiliary teeth 21a are F1 + F2≈0, as in the cogging thrust waveform shown in FIG.
The length Ht of the main teeth 21b and the length Hd of the auxiliary teeth 23 are set in the range of 0 <Hd <Ht, and the tooth width Bd of the auxiliary teeth 21a and the main teeth 2 are also set.
The tooth width Bt of 1b is set in the range of Bd <Bt. Under the above conditions, the linear motor can minimize the cogging thrust (for example, Japanese Patent Application No. 2000-118022).

[0004]

However, in the prior art, in order to reduce the cogging thrust, means for canceling the end effect of the end portion of the armature core or suppressing the influence of the end effect is taken. However, there is a problem in that the cogging thrust cannot always be reduced. That is, when designing a linear motor, the main tooth shape dimensions, design values such as the magnetic gap length between the field and the armature, and typical values of the magnetic characteristics of the permanent magnet used for the field are used. The shape and dimensions of the auxiliary teeth are determined by obtaining the conditions that minimize the cogging thrust. However, in the actually manufactured linear motor, dimensional variations and errors when punching the armature core, errors in the magnetic gap size when combining the field and armature, and when fixing the permanent magnet to the field yoke and assembling Due to dimensional variations and errors, variations in the magnetic characteristics of magnetic members such as armature cores, field yokes, and permanent magnets, and differences from the typical values, the dimensional conditions at which cogging thrust becomes almost zero deviate, and cogging thrust increases. Will end up. Therefore, to make a linear motor with a small cogging thrust close to the design value, this can be mitigated by repeating design and manufacturing based on actual shape measurement and cogging thrust evaluation. Since dimensional variations and errors in assembling the members, variations in the magnetic characteristics of the magnetic members, and differences from the representative values differ from case to case, they cannot be easily solved. The present invention has been made to solve the above-mentioned problems, and does not rely on repeated evaluation work by design and manufacture in the case of evaluating cogging thrust of a linear motor, and does not rely on the shape and size of an actual machine or the actual magnetic field of a magnetic member. An object of the present invention is to provide a permanent magnet type synchronous linear motor that can easily reduce the cogging thrust even if the characteristics deviate from the designed values.

[0005]

In order to solve the above problems, the present invention according to claim 1 is such that a plurality of permanent magnets are linearly arranged on the first field yoke so that the polarities are alternately different. A first field magnet, and a first armature arranged to face the first field magnet via a magnetic gap, the first armature, the first armature having a main tooth and a slot. 1 armature core, and a first armature winding having a coil wound around the slot of the first armature core, any one of the first field and the first armature In a permanent magnet type synchronous linear motor having one as a relatively movable element and the other as a stator, the first armature can relatively move to a position other than the side facing the first field. A vibration force with the same cycle as the cogging thrust is generated to cancel the cogging thrust that changes with the child. It is equipped with a vibrating force generating means. Further, the present invention according to claim 2 is the permanent magnet synchronous linear motor according to claim 1, wherein the vibrating force generating means is a surface other than a surface of the first armature facing the first field. A second field magnet formed by arranging a plurality of permanent magnets having different polarities alternately on a second field yoke provided on the second field yoke, and a second field magnet opposed to the second field magnet via a magnetic gap. An armature, and the second armature includes a slotless second armature core and a second armature winding in which an air-core coil is wound around the second armature core. Τm2, where τm1 is the magnetic pole pitch of the first field and τm2 is the magnetic pole pitch of the second field.
= Τm1 × 1/2. According to a third aspect of the present invention, in the permanent magnet synchronous linear motor according to the first aspect, the vibrating force generating means is the first
A comb-shaped core having a slot provided on a surface of the armature excluding a surface facing the first field, and a second armature facing the comb-shaped core with a magnetic gap therebetween. And the second armature includes a slotless second armature core and a second armature winding in which an air-core coil is wound around the second armature core, When the tooth pitch of the main teeth is τs1 and the tooth pitch of the teeth of the comb-shaped core is τs2, τ
s1 = τs2, and when the magnetic pole pitch of the first field is τm1 and the magnetic pole pitch of the second armature winding is τm2, the relationship of τm2 = τm1 × 1/2 I have. Further, the present invention according to claim 4 is the permanent magnet synchronous linear motor according to claim 1, 2 or 3, wherein auxiliary teeth are arranged at an end of the first armature core. Hd is the length in the direction orthogonal to the longitudinal direction of the first field, and Ht is the length of the main teeth in the direction orthogonal to the longitudinal direction of the first field.
And the length of the auxiliary teeth is 0 <Hd <Ht
It is set in the range of.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a side sectional view of a permanent magnet type synchronous linear motor of the present invention. Constituent elements of the present invention that are the same as those of the prior art are designated by the same reference numerals, and the description thereof will be omitted. It should be noted that the linear motors according to the first to third embodiments show an example of a gap facing type with 8 poles and 9 slots as in the prior art. Further, the setting of the range of the length Ht of the main teeth and the length Hd of the auxiliary teeth and the setting of the range of the tooth width Bt of the main teeth and the tooth width of the auxiliary teeth are the same as those in the conventional technique. In the figure, 3 is a vibration force generating means, 31
Is a second field magnet, 31a is a second field yoke, 31b is a permanent magnet, 32 is a second armature, 32a is a second armature core, and 32b is a second armature winding. The present invention is different from the prior art in the following points. That is, the first armature 2 moves relative to the first field 1 (stator) at positions (opposite sides) except the side facing the first field 1. 2 is provided with a vibrating force generating means 3 for generating a vibrating force having the same cycle as that of the cogging thrust so that the cogging thrust varying with the mover can be canceled out. By exciting with a current, an oscillating force is generated electromagnetically. Specifically, the vibrating force generating means 3 according to the present embodiment includes a second field provided on a surface (opposite side) of the first armature 2 excluding a surface facing the first field 1. Magnetic yoke 3
1a, a second field 31 formed by arranging a plurality of permanent magnets 31b alternately having different polarities, and a second armature 32 opposed to the second field 31 via a magnetic gap. It The second armature 32 is a slotless second armature.
Of the first armature core 32a and a second armature winding 32b in which an air-core coil is wound around the second armature core 32a. When the magnetic pole pitch of the field magnet 31 of is τm2, τm2 = τm
It has a relationship of 1 × 1/2. For convenience, the magnetic pole pitch of the second armature winding is not shown.

Next, the operation will be described. Linear motor first
When the field magnet 1 is moved in the longitudinal direction,
The cogging thrust changes with the movement of the armature 2 of
When a slight DC current is supplied to the vibration force generating means 3 provided on the surface (opposite side) of the first armature 2 excluding the surface facing the first field magnet 1, the vibration force generating means 3 causes the cogging thrust to be generated. The vibration force of the same cycle is generated, and the cogging thrust of the entire linear motor is reduced. Further, at this time, the vibrating force generating means 3 is not installed on the side of the first field 1 in the first armature 2, so that the action of the vibrating force generating means 3 affects the effective thrust as the linear motor. do not do.

Since the first embodiment has the above-mentioned structure, even when the cogging thrust becomes larger than the design value, the first embodiment
Cogging by energizing the second armature 2 by operating the vibrating force generating means 3 with a direct current corresponding to the magnitude of the cogging thrust generated between the field 1 and the first armature 2. The thrust can be returned to the minimum value that is the design value. This eliminates the need for repetitive evaluation work by designing and manufacturing when evaluating the cogging thrust of a linear motor, and makes it easy to reduce the cogging thrust even if the actual machine dimensions and the actual magnetic characteristics of magnetic members deviate from the design values. It is possible to provide a permanent magnet type synchronous linear motor capable of performing the above. Further, since the field generating source of the vibration force generating means 3 is the permanent magnet 12, no exciting current for generating the second field is required.
It is possible to further suppress an increase in power loss and a temperature rise due to the addition of the vibration force generating means 3. In addition, in the configuration in which the auxiliary teeth 23 are provided as in this example, the cogging thrust is smaller than that in the case where the auxiliary teeth are not provided, so that the power supplied to the vibration force generating means 3 is small and the vibration force is generated. It is possible to suppress an increase in power loss and an increase in temperature due to the addition of the means 3.

[Second Embodiment] Next, a second embodiment of the present invention will be described. FIG. 2 is a side sectional view of a permanent magnet type synchronous linear motor showing a second embodiment of the present invention. In the figure, 33 is a comb-shaped core. The second embodiment is the first
The points different from the embodiment are as follows. That is, the vibration force generating means 3 includes a comb-shaped core 33 having a slot provided on a surface (opposite side) of the first armature 2 excluding a surface facing the first field 1, and the comb-shaped core 33. And a second armature 32 opposed to each other via a magnetic gap, and the second armature 32 includes a slotless second armature core 32a and a second armature core 32a. It is composed of a second armature winding 32b around which an air-core coil is wound, and the tooth pitch of the main teeth 21b is τs.
1. When the tooth pitch of the teeth of the comb-shaped core 33 is τs2, the relationship of τs1 = τs2 is established. Although not shown, the first field 1
, Τm2 = τm1 × 1/2, where τm1 is the magnetic pole pitch and τm2 is the magnetic pole pitch of the second armature winding 32b.
It has a relationship of. Since the operation is the same as that of the first embodiment, its description is omitted.

Since the second embodiment has the above-mentioned configuration, even if the cogging thrust becomes larger than the design value, the first embodiment
Cogging by energizing the second armature 32 by operating the oscillating force generating means 3 with a direct current corresponding to the magnitude of the cogging thrust generated between the field 1 and the first armature 2. The thrust can be returned to the minimum value that is the design value.
This eliminates the need for repetitive evaluation work by designing and manufacturing when evaluating the cogging thrust of a linear motor, and makes it easy to reduce the cogging thrust even if the actual machine dimensions and the actual magnetic characteristics of magnetic members deviate from the design values. It is possible to provide a permanent magnet type synchronous linear motor capable of performing the above. Further, since a permanent magnet is not used for the vibration force generating means 3, it is possible to suppress an increase in cost associated with the addition of the vibration force generating means 3 and an increase in the number of assembling steps typified by mounting the permanent magnet.

[Third Embodiment] Next, a third embodiment of the present invention will be described. An example in which the vibrating force generation means 3 is installed on the side of the first armature, which is the thrust generation surface as a linear motor, opposite to the first field has been described in the first and second embodiments. As an example of installation of the vibration force generating means 3, there is one shown in FIGS. 3 (a) and 3 (b). FIG. 3 is a front view of a permanent magnet type synchronous linear motor according to a third embodiment of the present invention as viewed from the traveling direction. FIG. 3A is a gap facing linear motor in which an armature and a field face each other on one side. , (B) is an example applied to a magnetic flux penetration type linear motor in which the armature and the field face each other on both sides.
As shown in FIGS. 3 (a) and 3 (b), the vibration force generating means 3 is placed at a position where the first field 1 and the first armature 2 face each other and the table mounting surface 5 of the mover is avoided. It is good to install it. Since the third embodiment is configured as described above, the vibration force generating means 3 can be freely attached to the table of the mover according to the application, and the degree of freedom in design can be increased.

The second armature winding used in the vibrating force generating means in this embodiment may be a single-phase coil in which all element coils are connected in series, or the same number of phases as the first armature winding. It may be divided into two windings. In this case, since the peak position of the generated electromagnetic vibration force changes by adjusting the magnitude of the DC current flowing in the armature winding for each phase, the phase of the vibration force is electrically adjusted according to the cogging thrust. It becomes easy to do. Further, in the present embodiment, the first field and the second armature are configured as the stator, and the others are configured as the mover. However, the reverse or the replacement of the first field and the second armature is not possible. Freely selected. Further, in the present embodiment, the case where the slot shape is an open slot has been described, but it may be a semi-open slot, for example.

[0013]

According to the embodiments of the present invention, the following effects can be obtained. (1) Since the first embodiment is configured as described above, even if the cogging thrust becomes larger than the design value, the magnitude of the cogging thrust generated between the first field magnet and the first armature is The combined direct current is output to the second by operating the vibration force generating means.
By energizing the armature of, the cogging thrust can be returned to the minimum value that is the design value. This eliminates the need for repetitive evaluation work by designing and manufacturing when evaluating the cogging thrust of a linear motor, and makes it easy to reduce the cogging thrust even if the actual machine dimensions and the actual magnetic characteristics of magnetic members deviate from the design values. It is possible to provide a permanent magnet type synchronous linear motor capable of performing the above. Further, since the field generating source of the vibrating force generating means is a permanent magnet, an exciting current for generating the second field is not required. Therefore, an increase in power loss and a temperature rise due to the addition of the vibrating force generating means. Can be further suppressed. In addition, in the configuration in which the auxiliary teeth are provided as in this example, the cogging thrust is smaller than that in the case in which the auxiliary teeth are not provided, so that the power to be supplied to the vibration force generating means 3 can be small and the vibration force generating means can be used. It is possible to suppress an increase in power loss and a temperature rise due to the addition of.

(2) Since the second embodiment is configured as described above, even if the cogging thrust becomes larger than the design value, the cogging thrust generated between the first field magnet and the first armature is reduced. The cogging thrust can be returned to the minimum value which is the design value by supplying a direct current corresponding to the magnitude to the second armature by operating the vibrating force generating means. This eliminates the need for repetitive evaluation work by designing and manufacturing when evaluating the cogging thrust of a linear motor, and makes it easy to reduce the cogging thrust even if the actual machine dimensions and the actual magnetic characteristics of magnetic members deviate from the design values. It is possible to provide a permanent magnet type synchronous linear motor capable of performing the above. Furthermore,
Since a permanent magnet is not used as the vibration force generating means, it is possible to suppress an increase in cost associated with the addition of the vibration force generating means and an increase in the number of assembling steps represented by mounting the permanent magnet.

(3) Since the third embodiment has the above-mentioned structure, the vibrating force generating means can be freely attached to the table of the mover according to the use, and the degree of freedom in design can be increased.

[Brief description of drawings]

FIG. 1 is a side sectional view of a permanent magnet type synchronous linear motor showing a first embodiment of the present invention.

FIG. 2 is a side sectional view of a permanent magnet type synchronous linear motor showing a second embodiment of the present invention.

FIG. 3 is a front view of a permanent magnet type synchronous linear motor having a desirable structure in the first to fourth embodiments of the present invention as seen from the traveling direction.

FIG. 4 is a side sectional view of a conventional permanent magnet type synchronous linear motor.

FIG. 5 is a diagram showing a cogging thrust force waveform of a conventional permanent magnet synchronous linear motor.

[Explanation of symbols]

1st field 11 First field yoke 12 permanent magnet 2 First armature 21 First Armature Core 21a slot 21b Main teeth 22 First armature winding 23 Auxiliary teeth 3 Vibration force generation means 31 Second field 31a Second field yoke 31b Permanent magnet 32 Second Armature 32a Second armature core 32b Second armature winding 33 Comb core

Claims (4)

[Claims] 1. A first field magnet formed by arranging a plurality of permanent magnets linearly on the first field yoke so that the polarities thereof are alternately different, and a first magnetic field and a magnetic gap. And a first armature arranged so as to face each other, wherein the first armature is a first tooth having a main tooth and a slot.
An armature core and a first armature winding having a coil wound around a slot of the first armature core, and one of the first field magnet and the first armature In a permanent magnet type synchronous linear motor in which the other is a stator, and the other is a stator, in which the first armature is relatively movable to a position other than the side facing the first field. A permanent magnet synchronous linear motor characterized by comprising a vibrating force generating means for generating a vibrating force having the same cycle as the cogging thrust so that the cogging thrust varying with the above can be canceled out. 2. The vibrating force generating means has a plurality of alternating polarities on a second field yoke provided on a surface of the first armature excluding a surface facing the first field. It is composed of a second field formed by arranging permanent magnets, and a second armature arranged opposite to the second field via a magnetic gap, and the second armature is a slotless type. A second armature core and a second armature winding in which an air-core coil is wound around the second armature core, and the magnetic pole pitch of the first field is τm1, 2. The permanent magnet synchronous linear motor according to claim 1, wherein the relationship of τm2 = τm1 × 1/2 is established when the magnetic pole pitch of the field 2 is τm2. 3. The vibrating force generating means includes a comb-shaped core having a slot provided on a surface of the first armature excluding a surface facing the first field, and the comb-shaped core and the magnetic core. And a second armature facing each other with a gap in between,
The second armature includes a slotless second armature core and a second armature winding in which an air-core coil is wound around the second armature core. When the tooth pitch of the teeth is τs1 and the tooth pitch of the comb-shaped core is τs2, there is a relationship of τs1 = τs2, and the magnetic pole pitch of the first field is τm1 and the second magnetic pole pitch is the second magnetic field.
Τm2 when the magnetic pole pitch of the armature winding of
2. The permanent magnet type synchronous linear motor according to claim 1, which has a relationship of τm1 × 1/2. 4. An auxiliary tooth is arranged at an end portion of the first armature core, a length of the auxiliary tooth in a direction orthogonal to a longitudinal direction of the first field magnet is Hd, and the main tooth is The length of the auxiliary tooth is set in a range of 0 <Hd <Ht, where Ht is a length in a direction orthogonal to the longitudinal direction of the first field. The permanent magnet type synchronous linear motor described.