JP2003230264A - Linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motor capable of suppressing rising of temperature at driving. <P>SOLUTION: A linear motor (10) comprises a stator (20) provided with two yokes (21) arranged to be parallel to each other with interval, and a moving piece (30) which moves in the extending direction of the yoke between the two yokes. The yoke is provided with a cooling means (refrigerant 40) which recovers a heat generated by movement of the moving piece. Thus a rise in temperature when the linear motor is driven is suppressed, thus expansion or deformation of the stator and moving piece that follows the temperature rising is prevented. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor capable of suppressing a temperature rise during driving.

[0002]

2. Description of the Related Art Conventionally, a linear motor has been used in a device requiring high positioning accuracy, such as an electronic component mounting device for mounting electronic components on a substrate or a machine tool.
For example, in the center yoke type linear motor 100 shown in FIG. 8, the center yoke 1 is interposed between magnets 103 fixed to two yokes 102 as a stator 101.
04 is arranged, and the coil 1 as the mover 105.
06 is arranged so as to surround the periphery of the center yoke 104.

[0003]

By the way, in the general linear motor 100 as described above, in order to efficiently utilize the magnetic force of the magnet 103, the mover 105 and the stator 101 are provided.
Are arranged as close to each other as possible, but the temperature of the yoke 102 and the center yoke 104 rises due to the heat generation of the coil 106 when the linear motor is driven.
02 and the center yoke 104 are expanded or deformed by heat, and the clearance d1 between the coil 106 and the yoke 102 and the clearance d2 between the coil 106 and the center yoke 104 are changed, thereby changing the motor output characteristic. There is a problem that the magnet 103 and the center yoke 104 come into contact with each other. Further, there is a problem that the output performance deteriorates due to the temperature rise of the linear motor 100. Such a problem is also common to so-called coreless linear motors that do not have the center yoke 104.

An object of the present invention is to provide a linear motor capable of suppressing the temperature rise during driving in consideration of the above problems.

[0005]

In order to solve the above problems, the linear motor (10, 70) according to claim 1 has two yokes (21) arranged in parallel with each other and at a distance from each other.
A linear motor comprising a stator (20) provided with a mover (30) that moves between the two yokes in a direction in which the yoke extends, and heat generated by the mover of the mover in the yoke. It is characterized in that a cooling means (refrigerant 40, heat exchange element 80) for recovering is collected.

According to the first aspect of the present invention, the yoke is provided with the cooling means for recovering the heat generated by the movement of the mover, so that the temperature rise during the driving of the linear motor can be suppressed and the temperature It is possible to prevent the stator and the mover from expanding or deforming as they rise.

A linear motor according to a second aspect is the linear motor according to the first aspect.
The linear motor as described above, wherein the cooling means is a refrigerant, and a flow path (2) for enclosing the refrigerant inside the yoke.
5) is formed, and the refrigerant circulates in the flow path.

According to the second aspect of the present invention, the same effect as that of the first aspect can be obtained, and the refrigerant is used as the cooling means, and the refrigerant circulates in the flow path, so that no mechanical means is used. Therefore, the linear motor can be cooled, and the manufacturing cost of the linear motor can be suppressed. Further, if a device forcibly circulating the refrigerant is used, the cooling efficiency of the linear motor can be further improved.

According to a third aspect of the present invention, there is provided a linear motor according to the first aspect.
The linear motor described above, wherein the cooling means is a heat exchange element.

According to the third aspect of the present invention, the same effect as in the first aspect can be obtained, and since the heat exchange element is used as the cooling means, a refrigerant or a device for forcibly circulating the refrigerant is not required, The manufacturing cost of the linear motor can be suppressed.

According to a fourth aspect of the present invention, there is provided a linear motor, wherein two yokes are arranged in parallel with each other and are spaced apart from each other, and a center yoke is arranged between the two yokes in a direction in which the yoke extends. 23), and a mover that is arranged so as to surround the outer periphery of the center yoke and that moves between the two yokes in the extending direction of the yoke. Further, cooling means for recovering heat generated by the movement of the mover is disposed on at least one of the center yoke.

According to a fourth aspect of the present invention, at least one of the yoke and the center yoke,
Since the cooling means for recovering the heat generated by the movement of the mover is provided, it is possible to suppress the temperature rise when the linear motor is driven, and it is possible to prevent the stator and the mover from expanding or deforming due to the temperature rise. .

A linear motor according to a fifth aspect is the linear motor according to the fourth aspect.
The linear motor according to claim 1, wherein the cooling means is a refrigerant, and a flow path (25, 26) for enclosing the refrigerant is formed inside at least one of the yoke and the center yoke, and the refrigerant is the flow path. It is characterized by circulating inside.

According to the invention of claim 5, the same effect as that of claim 4 can be obtained, and a refrigerant is used as a cooling means, and the refrigerant circulates in the flow path. Therefore, a mechanical means is used. It is possible to cool the linear motor without having to do so, and it is possible to suppress the manufacturing cost of the linear motor. Further, if a device forcibly circulating the refrigerant is used, the cooling efficiency of the linear motor can be further improved.

A linear motor according to a sixth aspect is the linear motor according to the fourth aspect.
The linear motor described above, wherein the cooling means is a heat exchange element.

According to the invention of claim 6, the same effect as that of claim 4 can be obtained, and since the heat exchange element is used as the cooling means, a refrigerant or a device for forcibly circulating the refrigerant is unnecessary, The cost of the linear motor can be suppressed.

The linear motor according to claim 7 is the linear motor according to claim 2.
Alternatively, the linear motor according to the fifth aspect is characterized in that the yoke or the center yoke in which the flow path is formed is formed by joining two members each having a groove serving as a flow path.

According to the seventh aspect of the present invention, the same effect as the second or fifth aspect can be obtained, and the yoke or the center yoke is formed by joining two members each having a groove serving as a flow path. Therefore, the manufacturing work of the yoke and the center yoke becomes easy.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] A first embodiment of the present invention will be described in detail below with reference to the drawings.
As shown in FIG. 1, the linear motor 1 according to the present embodiment
Reference numeral 0 is a so-called center yoke type linear motor, which includes a stator 20, a mover 30, a cooling means (refrigerant 40), and the like. In FIG. 1, a part of the yoke 21 of the stator 20 is cut away.

The stator 20 includes two yokes 21, a plurality of magnets 22, a center yoke 23 and the like. The yoke 21 is a long plate-like body having magnetism.
The two yokes 21 are arranged in parallel with each other along the longitudinal direction (front-rear direction) and separated from each other by a substantially rectangular connecting member 24 joined to the lower part of the.

A flow path 25 is formed inside each yoke 21. The flow path 25 is a groove that has a diameter smaller than the width of the yoke 21 in the left-right direction and is formed in substantially the entire inside of the yoke 21 in order to seal the refrigerant 40 as a cooling means inside. As shown in FIG. 1, a plurality of flow paths 25 may be formed linearly in the front-rear direction, or, as shown in FIG. 2, a single groove is formed so as to meander inside the yoke 21. May be.

As a method of forming the flow path 25, for example, as shown in FIG. 3, one yoke 21 is divided into right and left,
A groove is formed in each of the divided half yokes 21a by etching or cutting, or the groove and the half yoke 21a are integrally formed by casting.
Examples include a method of joining a.

The flow path 25 is exposed at both front and rear ends of each yoke 21, and pipes 51 connected to a cooling device 50 (see FIG. 4) are connected to the exposed portions. In other words, the coolant 40 moving in the flow path 25 reaches the cooling device 50 through the pipe 51 connected to the rear end of the yoke 21, and the pipe 51 connected to the front end of the yoke 21 from the cooling device 50. By passing through and returning to the flow path 25 again,
It circulates in 5. A plurality of magnets 22 are provided on the inner surface of each yoke 21 side by side in the front-rear direction so that their polarities alternate.

The center yoke 23 is a long plate having magnetism, and is abutted on the connecting member 24 and the magnet 22 in the front-rear direction between the left and right yokes 21 by a center yoke supporting member (not shown). It is fixed in a position that does not. A flow passage 26 similar to the flow passage 25 formed in the yoke 21 is also formed inside the center yoke 23, and the pipe 51 is connected to the flow passages 26 exposed at both front and rear ends of the center yoke 23. Then, the cooling device 50 allows the refrigerant 40 to circulate in the flow path 26.

Although not shown, the connecting member 24 is formed with a plurality of vertically extending air holes in the front-rear direction, and cooling provided below the linear motor 10 through the air holes. Air from a fan (not shown) is introduced into the linear motor 10 or the linear motor 1
The linear motor 10 is cooled by discharging the air inside 0 to the outside of the linear motor 10.

The mover 30 has a plurality of cylindrical coils 31 forming an electromagnet arranged in the front-rear direction so that the coils 31 surround the outer circumference of the center yoke 23, that is, the coils 31 are arranged in the center yoke 23. It is configured to be inserted. Then, a magnetic field is generated by flowing a predetermined amount of current through the coil 31 under the control of the control unit 60 (see FIG. 4), and the attraction and repulsion between the coil 31 and the magnet 22 are used to move the mover. 30 moves in the front-back direction by a predetermined amount.

The control means 60 controls the amount of current flowing through the coil 31, the drive control of the cooling device 50, the drive control of the cooling fan, etc. based on various control data. Since the control of the amount of current flowing through the coil 31 and the drive control of the cooling fan are well known, the description thereof is omitted, and the drive control of the cooling device 50 will be described below.

As shown in FIG. 4, the cooling means 50 and the temperature measuring means 53 are joined to the control means 60. The cooling device 50 is a device for cooling the linear motor main body 11 composed of the stator 20 and the mover 30 by circulating the refrigerant 40, and the temperature measuring means 53 is a temperature sensor 52 attached to the linear motor main body 11. Is a device that measures the temperature of the linear motor main body 11 based on the signal output by.

When the mover 30 starts moving,
The temperature of the linear motor body 11 rises. The temperature measuring means 53 measures this temperature via the temperature sensor 52 and outputs it to the control means 60 as temperature data. The control means 60 determines the cooling amount of the linear motor main body 11 based on the temperature data, and drives the cooling device 50 based on the cooling amount. Specifically, for example, when the temperature rises with time, the circulation amount of the refrigerant 40 is increased, and when the temperature is lowered, the circulation amount of the refrigerant 40 is decreased. Adjust the temperature of and keep it below a certain temperature.

As described above, according to the linear motor 10 shown in the first embodiment, the refrigerant 4 is contained in the flow passages 25 and 26 formed inside the yoke 21 and the center yoke 23.
By circulating 0, it is possible to suppress the temperature rise when the linear motor main body 11 is driven, and the stator 2 accompanying the temperature rise
0 and the mover 30 can be prevented from expanding or deforming. Also, since the linear motor body 11 can be cooled efficiently,
The capacity of the cooling fan can be reduced, and the manufacturing cost of the linear motor 10 can be suppressed.

The present invention is not limited to the first embodiment and can be modified as appropriate. For example, in the present embodiment, the flow paths 25 and 26 are exposed at both the front and rear ends of the yoke 21 and the center yoke 23, and the pipes 51 of the cooling device 50 are connected to the exposed parts to cool the refrigerant 40 to the cooling device 50. However, the present invention is not limited to this. For example, as shown in FIG.
6 may be closed at both front and rear end portions of the yoke 21 and the center yoke 23. Note that FIG. 5 shows the yoke 2
Only 1 and the flow path 25 are shown.

Even in this case, the temperature of the refrigerant 40 is generally increased by driving the linear motor main body 11, but the refrigerant 4
0 The temperature of the whole does not rise uniformly, for example,
The temperature of the refrigerant 40 in the portion where the mover 30 repeatedly moves and stops increases first. That is, the refrigerant 40 has a temperature difference between a high temperature portion and a portion where the temperature hardly changes. Then, due to the difference in specific gravity between the high temperature portion and the low temperature portion of the refrigerant 40, spontaneous convection (circulation) occurs in the refrigerant 40, the heat of the high temperature portion is transferred to the low temperature portion, and the yoke Since the heat is radiated efficiently as a whole, the temperature rise of the linear motor main body 11 can be prevented.

In particular, depending on the application of the linear motor 10, the mover 30 does not move in the entire movable range but repeatedly moves in a partial region of the movable range, and the temperature of the refrigerant 40 locally rises. However, even in such a case, the heat absorbed by the coolant 40 can be cooled by using the coolant 40 having a low temperature, so that the linear motor main body 11 can be efficiently cooled. Further, the linear motor main body 11 can be cooled without using mechanical means such as the cooling device 50,
The manufacturing cost of the linear motor 10 can be suppressed.

Further, in this embodiment, the flow paths 25 and 26 are
Is formed on both the yoke 21 and the center yoke 2321, the present invention is not limited to this, and as shown in FIG.
The center yoke 2 that is easily affected by the heat generation of the coil 31
The flow passage 26 may be formed only in the groove 3, or may be formed only in the yoke 21. In FIG. 6, the yoke 21 and the center yoke 2
3 is partially cut away.

Further, the shapes and the numbers of the flow paths 25 and 26 can be arbitrarily changed. Further, although the present embodiment has been described using the center yoke type linear motor as the linear motor 10, the present invention is not limited to this, and the present invention is also applicable to a so-called coreless type linear motor that does not include the center yoke 23. Further, compressed air may be used as the cooling means, and the yoke 21 and the center yoke 23 may be cooled by utilizing the heat radiation of the compressed air sent to the flow paths 25 and 26.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIG. In addition,
In the linear motor 70 according to the present embodiment, parts having the same configurations as those of the above-described first embodiment are designated by the same reference numerals in the drawings, and the description thereof will be omitted. Further, in FIG. 7, the yoke 21 and the center yoke 2
3 is partially cut away.

The structure of this linear motor 70 differs from the linear motor 10 shown in the first embodiment in that the heat exchange element 8 is used without using the refrigerant 40 as the cooling means.
This is the point where 0 is used. As the heat exchange element 80, for example, a known device such as a heat pipe or a Peltier element is used. Then, a groove 90 similar to the flow paths 25 and 26 shown in the first embodiment is formed inside the yoke 21 and the center yoke 23, and the heat exchange element 8 is formed in the groove 90.
0 shall be attached. When an electrically driven device such as a Peltier device is used as the heat exchange element 80, the drive current is controlled by the control means 60.

The linear motor 7 shown in the second embodiment
According to 0, since the refrigerant 40 is not used, the cooling device 50
Is unnecessary, and the cost of the linear motor 70 can be suppressed. Further, the groove 9 for mounting the heat exchange element 80
Since the dimensional accuracy of 0 may be lower than that of the flow paths 25 and 26 in which the refrigerant 40 is sealed, the manufacturing efficiency of the linear motor 70 can be improved.

The present invention is not limited to the second embodiment and can be modified as appropriate. For example, in the present embodiment, the heat exchange element 80 is attached inside the yoke 21 and the center yoke 23, but the heat exchange element 80 may be attached outside the yoke 21 and the center yoke 23. . Further, the heat exchange element 80 may be attached to only one of the yoke 21 and the center yoke 23. Also,
In the present embodiment, the center yoke type linear motor is used as the linear motor 70, but the present invention is not limited to this, and the present invention can be applied to a coreless type linear motor that is not a general center yoke type.

[0040]

According to the first aspect of the invention, the yoke is provided with the cooling means for recovering the heat generated by the movement of the mover, so that the temperature rise during the driving of the linear motor can be suppressed. It is possible to prevent the stator and the mover from expanding or deforming as the temperature rises.

According to the second aspect of the present invention, the same effect as in the first aspect can be obtained, and a refrigerant is used as the cooling means, and the refrigerant circulates in the flow path, so that no mechanical means is used. Therefore, the linear motor can be cooled, and the manufacturing cost of the linear motor can be suppressed. Further, if a device forcibly circulating the refrigerant is used, the cooling efficiency of the linear motor can be further improved.

According to the third aspect of the present invention, the same effect as that of the first aspect can be obtained, and since the heat exchange element is used as the cooling means, a refrigerant or a device for forcibly circulating the refrigerant is unnecessary, The manufacturing cost of the linear motor can be suppressed.

According to the fourth aspect of the present invention, at least one of the yoke and the center yoke,
Since the cooling means for recovering the heat generated by the movement of the mover is provided, it is possible to suppress the temperature rise when the linear motor is driven, and it is possible to prevent the stator and the mover from expanding or deforming due to the temperature rise. .

According to the invention of claim 5, the same effect as in claim 4 can be obtained, and a refrigerant is used as a cooling means, and the refrigerant circulates in the flow path, so that a mechanical means is used. It is possible to cool the linear motor without having to do so, and it is possible to suppress the manufacturing cost of the linear motor. Further, if a device forcibly circulating the refrigerant is used, the cooling efficiency of the linear motor can be further improved.

According to the sixth aspect of the present invention, the same effect as that of the fourth aspect can be obtained, and since the heat exchange element is used as the cooling means, a refrigerant or a device for forcibly circulating the refrigerant is unnecessary, The cost of the linear motor can be suppressed.

According to the invention of claim 7, the same effect as that of claim 2 or 5 can be obtained, and a yoke or a center yoke is constructed by joining two members having a groove serving as a flow path. Therefore, the manufacturing work of the yoke and the center yoke becomes easy.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part showing a structure of a linear motor according to a first embodiment.

FIG. 2 is a vertical sectional view showing a flow path formed in a yoke.

FIG. 3 is a perspective view of relevant parts showing a method for manufacturing a yoke.

FIG. 4 is a block diagram showing a configuration of a linear motor.

FIG. 5 is a vertical cross-sectional view showing another flow path.

FIG. 6 is a main part perspective view showing the structure of another linear motor.

FIG. 7 is a main part perspective view showing the structure of a linear motor according to a second embodiment.

FIG. 8 is a main part perspective view showing the structure of a conventional linear motor.

[Explanation of symbols]

10 Linear motor 20 Stator 21 York 23 Center York 25 channels 26 channels 30 mover 40 refrigerant 70 Linear motor 80 Heat exchange element

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Anzai             1 J, 8-2 Kokuryo-cho, Chofu-shi, Tokyo             Within TUKI CORPORATION (72) Inventor Ichiro Okamoto             1 J, 8-2 Kokuryo-cho, Chofu-shi, Tokyo             Within TUKI CORPORATION (72) Inventor Naoyuki Yawata             1 J, 8-2 Kokuryo-cho, Chofu-shi, Tokyo             Within TUKI CORPORATION (72) Inventor Takeshi Moriyama             1-1 Eda Oda, Kawasaki-ku, Kawasaki-shi, Kanagawa             No. Showa Densen Denki Co., Ltd. (72) Inventor Satoshi Muranishi             1-1 Eda Oda, Kawasaki-ku, Kawasaki-shi, Kanagawa             No. Showa Densen Denki Co., Ltd. (72) Inventor Osamu Kokubo             1-1 Eda Oda, Kawasaki-ku, Kawasaki-shi, Kanagawa             No. Showa Densen Denki Co., Ltd. F term (reference) 5H609 BB08 BB12 BB18 PP02 PP06                       PP07 PP08 PP09 QQ01 QQ09                       RR37 RR41 RR51                 5H641 GG03 GG04 GG08 HH02 HH09                       JB04 JB05

Claims (7)

[Claims] 1. A linear motor comprising: a stator having two yokes arranged in parallel with each other and spaced apart from each other; and a mover moving between the two yokes in an extending direction of the yoke. A linear motor characterized in that cooling means for recovering heat generated by movement of the mover is arranged in the yoke. 2. The linear motor according to claim 1, wherein the cooling means is a coolant, a flow passage for enclosing the coolant is formed inside the yoke, and the coolant circulates in the flow passage. A linear motor characterized by that. 3. The linear motor according to claim 1, wherein the cooling means is a heat exchange element. 4. A stator comprising two yokes arranged in parallel with each other and spaced apart from each other, and a center yoke arranged between the two yokes along the extending direction of the yokes, A linear motor that is provided so as to surround the outer periphery of a center yoke, and that includes a mover that moves between the two yokes in the extending direction of the yoke, wherein at least one of the yoke and the center yoke has the A linear motor having a cooling means for recovering heat generated by movement of a mover. 5. The linear motor according to claim 4, wherein the cooling means is a refrigerant, and a flow path for enclosing the refrigerant is formed inside at least one of the yoke and the center yoke. A linear motor circulating in the flow path. 6. The linear motor according to claim 4, wherein the cooling means is a heat exchange element. 7. The linear motor according to claim 2, wherein the yoke or the center yoke in which the flow path is formed is formed by joining two members each having a groove serving as a flow path. A linear motor characterized by