JP3446563B2 - Linear motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor in which a permanent magnet and an armature coil are relatively moved.
The present invention relates to a technique for using a rectangular wire for an armature coil to suppress the amount of heat generated when energized. 2. Description of the Related Art Conventionally, as a driving device for moving and positioning over a long stroke, adjacent magnetic poles are magnetized so as to be different from each other, and magnetic gaps such that magnetic poles having different polarities face each other. And a plurality of permanent magnets fixedly arranged on the yoke via the armature coil, and an armature coil provided in the magnetic gap. By passing a drive current through the armature coil, the permanent magnet and the armature coil There is known a linear motor configured to relatively move. [0003] In the linear motor having such a configuration, a permanent magnet side is provided with a fixed magnetic gap so as to face each other, and an armature coil is moved in the magnetic gap. There are both types of movable magnet type linear motors in which the armature coil side is fixed and the permanent magnet side is moved. For example, in a conventional moving coil type linear motor, the polarity of an adjacent magnetic pole and the polarity of an opposing magnetic pole are arranged to be different from each other, and a magnetic band portion having a uniform air gap in the longitudinal direction. And a flat coil portion in which a plurality of coils are stacked such that the magnetic flux of the magnetic gap and the winding direction are orthogonal to each other. In such a configuration, in order to continuously move a long stroke, at least two or more coils are staggered to constitute a so-called polyphase coil, and the direction of the magnetic pole is detected by a magnetic field detecting element, and the current is detected. And the direction in which the current flows. [0006] In order to prevent current from flowing through the coil located at the boundary of the permanent magnet, it is better to construct as many polyphase coils as possible so that the coils can be sequentially switched and driven. For example, in the case of an N-phase coil, (N
Since the electromagnetic force is generated at the portion -1), the larger the number of phases, the larger the electromagnetic force with a small ripple. However, on the other hand, since the flat coils are stacked in multiple layers by the number of phases, the magnetic gap of the magnetic circuit must be increased accordingly. While the portion of the coil to be energized becomes longer, the magnetic flux density is reduced by the increase in the magnetic gap, and as a result, an electromagnetic force cannot be generated efficiently. Therefore, while maintaining the magnetic gap at a small interval,
When configuring flat coils in multiple phases to increase the number of coil turns per unit magnet and obtain a large moving force, the center of each flat coil is shifted on the same plane by each coil width and arranged on the same plane Then, means for regulating the central portion of the flat coil to a thickness of one phase is taken. On the other hand, although a plurality of flat coils could be formed in multiple phases without widening the magnetic air gap in this way, the amount of heat generated by the coils in the multi-phase when energized increased, and this time, Was required to solve this problem. The heat generated by the coil is transmitted to the permanent magnet disposed through a narrow magnetic gap. In the permanent magnet, the generated magnetic flux decreases due to thermal demagnetization, and the thrust of the linear motor decreases. Further, the heat generated by the coil increases the electric resistance of the coil itself, resulting in an increase in the loss of Joule heat, leading to a decrease in the effective power. Therefore, in order to prevent the adverse effects of heat generation from actually causing a problem, the amount of current supplied to the coil must be reduced, and the thrust of the linear motor must be sacrificed accordingly. Further, it has been reported that the linear guide may be thermally deformed due to an increase in the ambient temperature due to the heat generated by the coil, thereby lowering the positioning accuracy. As means for preventing the adverse effects of such heat generation,
Various means for cooling a coil by air cooling or water cooling have been proposed. In the air cooling system, for example, in a movable magnet type linear motor, a part of a yoke for closing a magnetic path of a field magnet is removed, and a through hole is provided in a yoke portion where no field magnet is arranged. A means for providing a cooling fan for sending cool air to the starter armature through the through hole is known (Japanese Patent Laid-Open No. 6-165472). Alternatively, in a movable magnet type linear motor, a mover including a field magnet and a yoke is divided, and a cooling fan for blowing air is provided between the divided movers on the coreless stator armature side. (JP-A-6-165474). As a water cooling system, means for directly cooling a coil with a refrigerant is known (Japanese Utility Model Laid-Open No. 6-41381).
issue). A coil is housed in an airtight container provided with a refrigerant supply port and a refrigerant exhaust port, and a refrigerant such as water is supplied to directly cool the coil, discharged, and the refrigerant radiated by the radiator is returned to the container again. is there. Further, a water-cooled method of indirectly cooling with a refrigerant is also known. For example, there is a method in which a long supporting member is provided at both ends in the width direction of an armature in which coils having an air core are arranged in a planar shape and a ladder shape, and a coolant flows through the long supporting member. This is a means for indirectly removing the heat transmitted from the coil to the long supporting member by heat transfer using a refrigerant. The conventional linear motor does not have a structure in which the air flow easily flows, so that sufficient and uniform cooling may not be expected in the air cooling system. Further, in the air cooling system, a space for installing a cooling fan is required, and it is difficult to reduce the size. On the other hand, in the water cooling method in which the coil is directly cooled by the refrigerant, the cooling can be performed more uniformly than in the air cooling method. On the other hand, since the field magnet is installed outside the container for cooling the coil, the coil and the field The magnet cannot be brought close enough. As a result, the thrust of the linear motor is limited. Further, in the above-mentioned water cooling system in which the coil is in direct contact with the refrigerant, the use of water as the refrigerant causes a problem of rust in the coil, and the use of oil causes a problem of safety in terms of explosion protection. On the other hand, in the water cooling system in which the refrigerant is indirectly cooled by the refrigerant, although the problems in the direct system can be avoided,
There is a problem that the cooling area cannot be sufficiently obtained and the cooling efficiency is inferior. In addition, the cooling rate of the coil is limited by the heat transfer rate of the coil, the heat transfer rate of the long support member provided on the armature, and the heat transfer rate of the contact surface between the coil and the long member. May not be expected. An object of the present invention is to make it possible to suppress the amount of heat generated by an armature coil in which a flat coil in a linear motor has a multi-phase structure. The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings. Means for Solving the Problems Of the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows. That is, in the present invention, first, a plurality of permanent magnets arranged on a yoke via a magnetic gap such that adjacent magnetic poles have different polarities and magnetic poles having different polarities face each other. And a moving coil type linear motor having an armature coil provided in the magnetic gap, and allowing a permanent magnet and the armature coil to relatively move by passing a drive current through the armature coil. Or a movable magnet type linear motor. Further, the armature coil used in the linear motor having the above-described structure is constituted by a multi-phase coil in which a plurality of flat coils are arranged with their respective center portions shifted by the coil width, so that the armature coil is constituted. Using a flat wire for the flat coil, the same amount of electricity, the same diameter, the same cross-sectional area,
The amount of heat generated at the time of energization can be suppressed as compared with the case of using a round wire. In the case of the flat wire winding, unnecessary gaps between the wires are not generated in the cross section even in the same space as compared with the round wire, and the same effect can be obtained as when the cross sectional area of the coil conductor is substantially increased. . In particular, flat wire is difficult to bend,
Of the flat coils having a multi-phase configuration, only the flat coils arranged flat may be used. Embodiments of the present invention will be described below in detail with reference to the drawings. In this embodiment, a moving coil type linear motor in which the armature coil 10 is constituted by a moving coil 10a will be described as an example. In this moving coil type linear motor, as shown in FIG. 1, a stationary portion A is provided in which a plurality of permanent magnets 20 are arranged in a longitudinal direction to form a traveling path. The stationary portion A is provided with a linear magnet band 40 facing the center so that magnetic gaps at regular intervals are linearly formed as the magnetic gap paths 30 at the center. Each of the magnet paths 40 provided on both sides is
The magnetic poles of the rectangular parallelepiped permanent magnet 20 are sequentially inverted, and the magnetic poles are formed in close contact with each other so that adjacent magnetic poles have different polarities. The individual permanent magnets 20 are arranged and fixed to the side yokes 50 in the above-described manner, and form the linear magnet paths 40, respectively. The permanent magnet 20 may be fixed to the side yoke 50 by an adhesive using an adhesive, or may be fixed by screws so that the permanent magnet 20 can be removed at the time of repair. [0034] The magnet band 40 on the other side faces the linear magnet band 40 constructed in this manner with a predetermined magnetic gap, and the permanent magnet 20 is connected to the side yoke 50 in the above-described manner. Formed by fixing to Further, the respective permanent magnets 20 constituting the magnet path 40 are arranged such that magnetic poles of different polarities face each other with the magnetic gap path 30 interposed therebetween. On the other hand, the two magnet belts 40 arranged linearly facing each other with a magnetic gap at a predetermined interval in the center in the manner described above,
The both ends are integrally attached to the end yoke 60 and the lower end is integrally attached to the plate 70 (FIG. 2), so that the stationary portion A is formed as a whole. The side yoke 50, the end yoke 60, and the plate 70 having the above-described configuration are formed of a ferromagnetic material such as mild steel. In the stationary unit A thus configured,
Since the magnetic poles of the facing permanent magnet 20 and the adjacent permanent magnet 20 are configured to have different polarities, FIG.
A magnetic flux line B as shown in FIG. At the same time, a magnetic flux perpendicular to the longitudinal direction exists in the linear magnetic gap path 30 formed between the two magnet bands 40. On the other hand, as shown in FIG. 2, a movable portion D for moving the armature coil 10 formed on the mover C along the magnetic gap path 30 having the above-described structure includes a permanent magnet facing both magnet bands 40. Moving coil 1 provided in magnetic gap 30 between 20
0a (10), a coil fixing jig 11, a table 12 provided on the coil fixing jig 11 side, and a linear guide 1
And 3. The movable coil 10a includes a coil fixing jig 11
Is fixed to the table 12 by the
A slider section 14 having a substantially concave cross section at the lower opening of the linear guide 13 fixed to the second guide 2 is engaged with a track base 15 having a substantially convex cross section fixed to the stationary portion A, and along the track base 15. Can be moved. As shown in FIG. 3, the movable coil 10a is formed by flat coils a, b, and c superposed in multiple phases. The winding such as the flat coil a is formed in a plane in the longitudinal direction orthogonal to the magnetic flux. Further, in the portion of the two magnet paths 40 sandwiched between the permanent magnets 20, the movable coil 10a
As shown in FIG. 5, it has a single-phase thickness. Also,
The upper and lower ends of the movable coil 10a are thicker by three phases of flat coils a, b, and c which are stacked in multiple phases. As shown in FIGS. 3 and 4, the movable coil 10a is provided on both sides of the coil frame 80 in this embodiment.
The three flat coils a, b, and c are shifted by the coil width L, and are formed in three phases such that the central part has a thickness of one phase. The coil frame 80 is made of a non-magnetic material in order to prevent thrust ripple from being generated.
Using an aluminum alloy having a surface anodized to impart insulation, a synthetic resin substrate such as an epoxy resin containing glass is mounted on the surface, and flat coils a, b, and c is provided for three phases. On the central flat surface of the coil frame 80 having the above-described structure, a flat coil a (indicated by oblique lines rising to the right in the figure) is provided in a plane. A flat wire is used for the flat coil a. In the present embodiment, the coil width L of the flat coil a is set to be one third of the length of the permanent magnet 20, and a central empty portion (shown by a broken line) E surrounded by windings.
Is set to have a width 2L which is twice the coil width L. On the flat coil a, a flat coil b using a round wire whose winding is easily bent and deformed is overlapped with the center portion shifted by the coil width L. Flat coil b (in the figure,
As shown in FIG. 4, the scattered spots are provided so as to be shifted by the coil width L so that the winding of the flat coil b enters the center empty portion E of the flat coil a. In the center empty portion E of the flat coil a, FIG.
As shown in FIG. 5A, the flat coil a and the flat coil b do not overlap each other, so that the thickness becomes one phase. However, in the upper and lower portions of the flat coil a, as shown in FIG.
The flat coils b overlap and have a thickness of two phases. As shown in FIGS. 3 and 4, a flat coil c (shown by diagonally lower right in the figure) is further superimposed on the flat coils a and b thus superimposed by two phases. Is configured. The flat coil c of the third phase includes a flat coil b
Similarly, a round wire that is easily bent and deformed is used, and is provided at the center empty portion E of the flat coil a, shifted by the coil width L, and further shifted by the coil width L beside the flat coil b arranged in advance. . The flat coils a, b, and c are provided side by side in a three-phase arrangement in the center empty portion of the flat coil a. Accordingly, in the center empty portion E of the flat coil a, as shown in FIG. 5C, three flat coils a,
b and c do not overlap and have a thickness of one phase. On the other hand, in the upper and lower portions of the flat coil a, FIGS.
As shown in (c), the flat coils b and c are sequentially superimposed to have a thickness of three phases. The three phases of the flat coils a, b, and c are formed on both sides of the coil frame 80 as shown in FIG. Note that the number of flat coils configured in multiple phases is
It is not necessary to limit the number to three, and four or more may be used.
Further, a flat coil may be provided only on one side of the coil frame 80. Further, in the movable part D described above, one magnetic gap path 30 is formed at the center while being sandwiched between the side yokes 50 of the magnet bands 40 on both sides. And the two magnetic gap paths 30 are passed in parallel, and the movable coil 1 is passed through both magnetic gap paths 30 as described above.
0a may be movable. In FIG. 5A, flat coils a are provided flat on both sides of the coil frame 80. FIG. 5 (b)
In this embodiment, a flat coil b is stacked on a flat coil a provided on both sides of the coil frame 80 without overlapping the center empty portion E but with the upper and lower portions. FIG. 5 (c)
In this embodiment, a flat coil c is superimposed on a flat coil a, which is provided flat on both sides of the coil frame 80, and a flat coil b which is superimposed on the flat coil a, not on the center empty portion E, but on the upper and lower portions. The flat coils a, b, c of the above construction
When moving the magnetic gap path 30 as the movable coil 10a, the polarities of the magnetic poles of the permanent magnets 20 on both sides of the magnet band 40 are sequentially reversed as the movable coil 10a passes. Is connected to the power supply side so that the current sequentially flows in the opposite direction in the movable coil 10a. The connection to the power supply side is performed by, for example, detecting the position using a magnetic detecting element or an optical position detecting element.
The direction of the current to each of the flat coils a and the like is changed based on the detection signal. In this manner, as shown in FIG. 4, the movable coil 10a according to the present embodiment is such that the portion accommodated in the magnetic gap between the facing permanent magnets 20 of the two magnet bands 40 is formed by the flat coil a. The thickness is reduced to one phase, and the part deviating from the magnetic gap is formed to have a three-phase structure. On the other hand, in the conventional movable coil 10a in which the flat coils are formed in three phases, round wires are used for all the flat coils.
A flat wire is used for the flat coil a provided flat. Therefore, unlike the movable coil having the conventional configuration, the use of the flat wire has no unused space between the wires, and the conductor is substantially thicker than the case of using the round wire with the same cross-sectional area. The same effect as described above is produced, and the calorific value can be suppressed lower than that of the flat coils b and c using round wires. As described above, in the linear motor of the present embodiment, the temperature rise of the permanent magnet 20 is reduced by the amount corresponding to the fact that the calorific value can be reduced as compared with the conventional mover coil composed of the multi-phase flat coil. By doing so, it is possible to prevent a decrease in thrust due to thermal demagnetization. In the above-described embodiment, the flat coils a, b, and c having a multi-phase structure are configured so that the upper and lower portions are overlapped with three phases. b and c do not necessarily have to overlap. On the upper and lower space sides outside the magnetic air gap 30,
Since it is a free space where the permanent magnets 20 and the like do not approach to the left and right, the flat coils a, b, c
Any shape can be considered. For example, as shown in the cross-sectional view of FIG. 6, a space may be provided between the flat coils a, b, and c so that the heat of the flat coils a, b, and c is easily generated. The moving coil type linear motor having the moving coil 10a composed of the flat coils a, b, and c having such a structure operates as follows. As shown in FIG. 7, a flat coil a (in the figure,
When a drive current in the same direction is applied to the flat coil b (indicated by a dotted line in the figure) and the flat coil b (indicated by a dotted line), as shown in FIG. Direction), the movable coil 10a moves. The directions of currents flowing through the flat coils a and b are indicated by a 'and b' in the figure. Next, the flat coil a is
When it moves to the center position of 0, the position is detected by, for example, a magnetic detection element or the like, and the drive current is applied to the flat coils a and b in the same manner as described above. be changed. The current directions of the flat coils b and c are indicated by b 'and c', respectively. By changing the application of the driving current to the flat coils b and c in this manner, a force acts on the flat coils b and c in the rightward direction (arrow direction) as shown in FIG. Then, the movable coil 10a moves to the position shown in FIG. In this manner, by sequentially switching the flat coils a and b and the flat coils b and c and the driving current, the movable coil 10a can move the magnetic gap path 30 continuously. In this embodiment, the moving coil type linear motor has been described as a representative example. It is the same even if is applied. Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments and can be variously modified without departing from the gist thereof. Needless to say, there is. The effects obtained by the typical inventions among the inventions disclosed in the present application will be briefly described.
It is as follows. (1). In the present invention, since a flat wire is used for the flat coil of the multi-phase coil constituting the armature coil, the armature coil at the time of movement can be compared with a conventional case using only a round wire. The amount of heat generated can be suppressed. (2). According to the present invention, the flat wire is used for the flat coil provided on the coil frame of the armature coil formed of the multi-phase coil, so that the bending of the flat wire can be omitted.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing a linear motor according to an embodiment of the present invention. FIG. 2 is a sectional view showing a configuration of a movable portion of the linear motor according to the present invention. FIG. 3 is a perspective view showing a configuration of a multi-phase coil in the movable coil. FIG. 4 is a plan view showing a configuration of a multi-phase coil in the movable coil. FIG. 5A is a cross-sectional view taken along line AA showing a configuration of a multiphase coil in the movable coil shown in FIG. 4; (B)
FIG. 6 is a sectional view taken along line BB showing a configuration of a multiphase coil in the movable coil of FIG. 4. FIG. 6C is a cross-sectional view taken along line CC of the configuration of the multi-phase coil in the movable coil of FIG. 4. FIG. 6 is a cross-sectional view illustrating a modification of the multi-phase configuration of the flat coil. FIG. 7 is an explanatory diagram showing an operation state of a linear motor. DESCRIPTION OF SYMBOLS 10 Armature 10 a Moving coil 11 Coil fixing jig 12 Table 13 Linear guide 14 Slider section 15 Track base 20 Permanent magnet 30 Magnetic gap path 40 Magnet path 50 Side yoke 60 End yoke 70 Plate 80 Coil frame a Flat coil b Flat coil c Flat coil A Stationary part B Magnetic flux line C Moving part D Movement E Center free space L Coil width

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-317627 (JP, A) JP-A-6-38503 (JP, A) JP 5-91190 (JP, U) JP 6-38 21352 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 41/02 H02K 33/18

Claims (1)

(57) [Claims 1] A plurality of permanent magnets arranged on a yoke via a magnetic gap so that adjacent magnetic poles have different polarities and magnetic poles of different polarities face each other. When having an armature coil provided in the magnetic gap, said armature coil, each of the central portion of the plurality of flat coils are stacked while sequentially shifting the coil width of coplanar, A linear motor in which the central portion is arranged so as to have a thickness of one phase, and a drive current is supplied to the armature coil to relatively move the permanent magnet and the armature coil. Wherein the plurality of stacked flat coils are folded using a flat wire.
Unfolded flat coil and flat wire bent using round wire
A linear motor comprising a coil .