JPH0345623B2 - - Google Patents

Description

[Detailed Description of the Invention] In the present invention, both the stator and the mover have a large number of concave and convex magnetic pole teeth made of magnetic material, and the mover performs linear motion while maintaining a constant distance from the stator. This technology is related to linear motors such as the Mover, and reduces the component of the magnetic attraction force acting between the stator and the mover in the direction perpendicular to the stator without increasing the weight of the mover. It is an object of the present invention to provide a lightweight linear motor with low operating noise and long life of movable element guide means such as pairing by reducing the load force acting on the means.

In a linear motor in which the mover maintains a constant distance from the stator and moves due to the magnetic attraction force acting between the mover and the stator, it is the magnetic force that is involved in the thrust of the mover. A force component of the attraction force in a direction parallel to the stator (longitudinal direction), and a component force in a direction perpendicular to the stator becomes a load force acting on the movable element guide means, and the load force is large. This shortens the life of the movable element guide means such as pairing, and also increases the operating noise of the motor.

FIG. 1 schematically shows a conventional example of a linear motor designed to reduce the component of the magnetic attraction force acting between a movable element and a stator in a direction perpendicular to the stator. It is a diagram. In the same figure, 1
2 represents a stator made of a magnetic material, and 2 represents magnetic pole teeth formed on the stator 1 at a constant pitch in its longitudinal direction. 3 is the core of the mover, which is made of a magnetic material. Reference numeral 4 denotes magnetic pole teeth of a mover formed on the surface of the core 3 facing the stator 1;
It is formed with the same pitch as the magnetic pole teeth 2 of. A first permanent magnet 5 is mounted on the movable element and is related to the thrust of the motor. Reference numeral 6 denotes a support member made of a non-magnetic material attached to the front and rear of the movable element, to which a pairing 7 and a yoke 8 are attached. The pairing 7 serves to enable the movable element to smoothly move relative to the stator while maintaining a constant distance between the movable element and the stator. A yoke 8 made of a magnetic material has a second permanent magnet 9 sandwiched in the center thereof, and is connected to the core 3 by the support member 6 made of a non-magnetic material. 10a and 10b are excitation windings wound around the core 3.

In this conventional example, the so-called SAWYER-
Linear, traditionally known as MOTOR
A magnetic circuit (the second permanent magnet 9,
The yoke 8 made of the magnetic material and the stator 1) are provided. The core 3
The force of the component of the magnetic attraction force acting between the yoke 8 and the stator 1 in a direction perpendicular to the stator 1 is reduced by the magnetic attraction force acting between the yoke 8 and the stator 1. This is what I am trying to do. G between the yoke 8 and the stator 1 and the size of the second permanent magnet 9 are such that no matter how fast the mover moves relative to the stator, the yoke 8 is It is selected to avoid adsorption to 1. In such a conventional example, a member (the first permanent magnet 5 and the core 3) that generates a thrust force on the mover and a magnetic attraction force acting between the mover and the stator perpendicular to the stator. Since the members (the second permanent magnet 9 and the yoke 8) that reduce the component in the direction of Acceleration is poorer than a linear motor that does not have a component to reduce the component. In addition, as shown in Fig. 1, the magnetic flux φ ₁ created by the member that generates thrust in the mover (Fig. 1 shows the magnetic flux when the coil 10a is energized) and the relationship between the mover and the stator. The magnetic flux φ ₂ created by the member that reduces the component of the magnetic attraction force in the direction perpendicular to the stator that acts between the stators flows through the common stator 1, so they tend to cause magnetic interference with each other and the thrust tends to decrease. It is. To prevent this,
It is necessary to make the thickness t of the stator 1 sufficiently thick, or to separate the magnetic paths of the magnetic fluxes φ ₁ and φ ₂ by dividing the stator 1 into upper and lower parts and sandwiching a non-magnetic material in the center. It is.

The linear motor of the present invention eliminates the above-mentioned conventional drawbacks, and a part of the magnetic flux related to the thrust of the mover is replaced by a component of the magnetic attraction force acting between the mover and the stator in the direction perpendicular to the stator. It is configured to also play a role of reducing the force in the direction perpendicular to the stator of the magnetic attraction force that acts between the member that generates thrust on the mover, the mover, and the stator. The members are made of the same material, and the load force acting on the mover guide means can be reduced without increasing the weight of the mover, and the magnetic flux related to the thrust of the mover and the mover can be reduced. There is no mutual interference with the magnetic flux, which is related to reducing the load force acting on the guide means, and the magnetic attraction force that acts between the mover and stator can be maintained without any special measures to separate the two. Reducing the component in the direction perpendicular to the stator has no effect on reducing the thrust of the mover. Therefore, it is possible to provide a linear motor that can reduce the load force acting on the movable element guide means while maintaining acceleration performance, has quiet operating noise, and has a long life of the guide means.

Hereinafter, the present invention will be explained based on illustrated embodiments. 2 and 3 are diagrams showing the first embodiment of the present invention, FIG. 2 is a perspective view, and FIG. 3 is a perspective view.
3 is a front view, and FIG. 3b is a sectional view taken along line A-A' in FIG. 3a. However, in both figures, lead wires, connectors, etc. connected to the motor are omitted.

In FIGS. 2 and 3, reference numeral 11 denotes a stator made of a magnetic material, and its cross-sectional shape in a plane perpendicular to its longitudinal direction is approximately U-shaped, and its inner surface 11a and 11b are configured in parallel. The stator 11 can be manufactured by cutting a square bar made of magnetic material, but it can also be assembled from three members 11c, 11d, and 11e made of magnetic material, as shown in FIG. It is possible. Furthermore, as shown in FIG. 5, it is also possible to assemble two members 11c and 11f made of magnetic material. 12 is the stator 1
1 shows stator magnetic pole teeth formed at a constant pitch on the surface 11b. The magnetic pole teeth 12 can be formed by machining, but the magnetic pole teeth 12
By etching a plate made of a magnetic material having a thickness corresponding to the height of the teeth, a number of slits having a width corresponding to the recess of the magnetic pole teeth 12 are formed to have the same width as the magnetic pole teeth 12. It can also be formed by adhering an etched plate made of pitch to the surface 11b of the stator 11. Reference numeral 13 denotes the core of the mover, which is made of a magnetic material, and has three field parts 25a, 25b, and 25c in the longitudinal direction.
is formed. 14 are the three field parts 25
Mover magnetic pole teeth are formed at the same pitch as the magnetic pole teeth 12 of the stator 11 on the respective end faces of the stator 11, and each of the field portions 25
The phases of the magnetic pole teeth of a, 25b, and 25c are each shifted by 1/3 pitch. 15
is a permanent magnet mounted on the mover, and is fixed in close contact with the surface of the core 13 opposite to the surface on which the magnetic pole teeth 14 are formed, and is attached in a direction perpendicular to the fixed surface. It is magnetized. 16 is pairing 1
This is a pairing support member made of a non-magnetic material that supports 7. The pairing 17 plays the role of smoothly moving the movable element relative to the stator 11 while keeping _G1 constant between the core 13 and the stator 11. A guide rail 18 is provided along the stator 11 on the end face of the portion of the stator 11 where the magnetic pole teeth 12 are formed. 19 is a side plate made of a non-magnetic material attached to one side of the mover;
It plays a role of supporting the pairings 20, 20. Reference numeral 21 denotes an auxiliary plate that supports the pairing 20', and is configured to be rotatable about a shaft 22 provided on the side plate 19. 3 pairings 20, 20, 2
0' guides the mover by sandwiching both sides of the guide rail 18 so that the mover moves along the stator 11.

The auxiliary plate 21 and the side plate 1
9 is connected by a spring 23, and the spring 23 brings the two pairings 20, 20 directly attached to the side plate 19 into contact with one surface of the guide rail 18 with appropriate pressure, and The one pairing 20' attached to the auxiliary plate 21 is brought into contact with the other side of the guide rail 18 with appropriate pressure, and the guide rail 18 is connected to the three pairings 20,
Insert from both sides at 20, 20'. In this way, by sandwiching the guide rail 18 along the stator 11 at the end of the stator 11 with at least three pairings on both sides of the guide rail 18, the movable element can be moved along the stator 11. In the method of guiding along the stator 11 and the core 13, all the guiding mechanisms can be placed on one side of the mover, so the stator can be effectively placed in the space on the other side of the mover. The structure can be such that the length of the magnetic path created by the permanent magnet 15 is shortened. As a result, the leakage of the magnetic flux of the permanent magnet 15 can be reduced, and the decrease in the thrust of the motor due to the leakage of the magnetic flux can be alleviated. 24a,
24b, 24c are the field parts 25a, 25b,
25c shows the excitation windings wound respectively.

Next, the operating principle of the first embodiment of the present invention will be explained. FIG. 6 is a diagram for explaining the operating principle of the first embodiment. In the same figure, φm
The permanent magnet 15 causes the field portion 25a,
It represents the magnetic flux generated within 25b and 25c.
Moreover, φa, φb, φc are the excitation windings 24a, 24
The magnetic fluxes generated when magnets b and 24c are excited are respectively shown. FIG. 6a is a diagram showing the flow of magnetic flux when the excitation winding 24a is excited. If the magnetic fluxes generated in the field parts 25a, 25b, and 25c are respectively φ _P1 , φ _P2 , and φ _P3 , then φ _P1 =φ _n +φ _a …(1) φ _P2 =φ _n −1/2φ _a …(2) φ _P3 =φ _n −1/2φ _a …(3). Here, by adjusting the excitation current or the number of turns of the excitation winding 24a and controlling φ _a , it is possible to make it so that φ _P1 ≫ φ _P2 , φ _P1 ≫ φ _P3 (4) can.

In such a state, the field portion 25a
A strong flow of magnetic flux is generated, the field portion 25a is strongly attracted to the magnetic pole teeth 12 of the stator 11, and thrust is generated. FIG. 6b is a diagram showing the flow of magnetic flux when the excitation winding 25b is excited.
Magnetic fluxes generated in 5a, 25b, 25c φ _P1 , φ _P2 ,
φ _P3 becomes φ _P1 =φ _n −1/2φ _b …(5) φ _P2 =φ _n +φ _b …(6) φ _P3 =φ _n −1/2φ _b …(7), and the excitation winding 24b By adjusting the excitation current or the number of windings and controlling φ _b , it is possible to make φ _P2 ≫ φ _P1 , φ _P2 ≫ _{φ P3} (8).

In such a state, the field portion 25b
A strong flow of magnetic flux is generated, the field portion 25b is strongly attracted to the magnetic pole teeth 12 of the stator 11, and thrust is generated. FIG. 6c is a diagram showing the flow of magnetic flux when the excitation winding 24c is excited;
Magnetic fluxes generated in 5a, 25b, 25c φ _P1 , φ _P2 ,
φ _P3 becomes φ _P1 = φ _n −1/2φ _c …(9) φ _P2 = φ _n −1/2φ _c …(10) φ _P3 =φ _n +φ _c …(11), and the excitation winding 24c By controlling φ _c by adjusting the excitation current or the number of turns, it is possible to make φ _P3 ≫ φ _P1 , φ _P3 ≫ _{φ P2} (12).

In such a state, the field portion 25c
A strong flow of magnetic flux is generated, the field portion 25c is strongly attracted to the magnetic pole teeth 12 of the stator 11, and thrust is generated. Each of the field parts 25a, 25b,
Since the phases of the magnetic pole teeth formed in 25c are shifted by 1/3 pitch, the present invention can be achieved by selectively and sequentially exciting the excitation windings 24a, 24b, and 24c. The linear motor shown in the first embodiment moves in 1/3 pitch increments.
Further, as shown in FIG. 6, the magnetic flux of the permanent magnet 15 is between the core ₁₃ of the movable element and the stator 11,
1, the component force in the direction perpendicular to the stator ₁₁ of the magnetic attraction force acting on the movable element passes through the stator ₁₁ which is generated at the distance G1.
The force F _G1 on the surface 11b of the stator 11, and the force F _G2 on the surface 11a of the stator ₁₁ generated in the gap G2. In particular, since F _G2 acts in a direction that cancels out the F _G1 ,
The force of the component of the magnetic attraction force acting on the movable element in the direction perpendicular to the stator 11 is F _G1 - F _G2 . Therefore, according to the present invention, it is possible to reduce the component of the magnetic attraction force acting between the movable element and the stator in the direction perpendicular to the stator. The distance G ₂ is set within the range G ₂ > G ₁ so that no matter how fast the mover moves relative to the stator 11, it will not stick to the surface 11a of the stator 11. Select.
Further, as described above, the magnetic flux φ _n of the permanent magnet 15 necessary to generate thrust in the mover is the component of the magnetic attraction force acting between the mover and the stator in the direction perpendicular to the stator. Since it is configured to also play the role of reducing force, it reduces the component of the magnetic attraction force that acts between the member that generates thrust on the mover, the mover, and the stator in the direction perpendicular to the stator. Since the member to be reduced is the same, the load force acting on the movable element guide means can be reduced without increasing the weight of the movable element. Further, since a part of the magnetic flux related to the thrust of the movable element becomes a magnetic flux that reduces the load force acting on the movable element guide means, the magnetic flux related to the thrust of the movable element and the movable element guide means There is of course no magnetic interference between the magnetic flux and the load force acting on it.

FIG. 7 is a diagram showing the principle configuration of the second embodiment of the present invention, in which the movable element guide means including the means for maintaining the space between the movable element and the stator are the same as in the above-mentioned first embodiment, and are therefore omitted. It has been done. FIG. 7a shows a front view, and FIG. 7b shows a side view. In the same figure, parts with the same numbers as in the first embodiment indicate the same members as in the first embodiment. As in the first embodiment, the movable element is disposed inside the U-shaped stator 11 with a distance G ₁ and G ₂ (G ₂ >G ₁ ) apart. The core of the mover is composed of two magnetic members, a first core 26 and a second core 27, and the first core 26 connects the three field parts 30a, 30b, 30c to the stator 11. The second core 27 has three field parts 31a, 31b, 31c in the stator 11.
It has in the longitudinal direction. Reference numeral 28 denotes first mover magnetic pole teeth formed on the surface of the first core 26 facing the stator 11, and the field portions 30a,
30b and 30c, and the phase of each field portion is shifted by 1/3 pitch. Reference numeral 29 denotes second mover magnetic pole teeth formed on the surface of the second core 27 facing the stator 11;
A, 31b, and 31c are formed on each end face, and the phase of each field portion is shifted by 1/3 pitch. Furthermore, the magnetic pole teeth 28 of the first core 26 and the second core 27
The magnetic pole teeth 29 are formed with a phase shift of 1/2 pitch from each other. When the magnetic pole teeth are formed in this way, the phase of the magnetic pole teeth of the field section 31c is shifted by 1/6 pitch with respect to the magnetic pole teeth of the field section 30a, and the magnetic pole teeth of the field section 30b are 2/6
pitch, the magnetic pole teeth of the field part 30c are 4/6 pitch,
The magnetic pole teeth of the field section 31b are shifted in phase by 5/6 pitches. Therefore, the field section 3
If 0a to 30c and 31a to 31c are sequentially excited as follows, the motor of the second embodiment of the present invention will step by 1/6 pitch.

30a → 31c → 30b → 31a → 30c → 3
1b...(13) 32a is an excitation winding wound across the field parts 30a and 31b;
The wires a and 31a are wound in opposite directions. 32b is an excitation winding wound across the field parts 30b and 31b;
0b and 31b are wound in opposite directions. 32c is an excitation winding wound across the field parts 30c and 31c;
0c and 31c are wound in opposite directions. The excitation windings 32a, 32b, 32c have an eighth
When a drive current as shown in the figure is applied, the field parts 30a to 30
c and 31a to 31c are sequentially excited, and the motor shown in the second embodiment of the present invention advances by 1/6 pitch. Also in the second embodiment, it is possible to reduce the force in the direction perpendicular to the stator of the magnetic attraction force acting between the mover and the stator, and the force between the mover and the stator is ₂ , the load force acting on the mover guide means can be reduced without increasing the weight of the mover, and a part of the magnetic flux related to the thrust of the mover acts on the mover guide means. Since the magnetic flux reduces the load force, the effects such as the absence of magnetic interference between the two are exactly the same as in the case of the first embodiment of the present invention described above. Further, in the first and second embodiments of the present invention, the movable element may be constructed by closely contacting a parallel flat plate made of a magnetic material onto the permanent magnet 15. Further, depending on the number of field parts, a four-phase motor, a five-phase motor, etc. may be used. Further, in addition to the driving method described in the main text, the linear motor of the present invention can be driven by various driving methods such as multiphase excitation driving and microstep driving. In particular, by providing a position detector and performing closed-loop control, it is also possible to operate it as a normal servo motor.

As is clear from the above description, in the linear motor of the present invention, part of the magnetic flux related to the thrust of the mover is generated by the magnetic attraction force acting between the mover and the stator in the direction perpendicular to the stator. The member that generates the thrust force on the mover and the member that reduces the component of the magnetic attraction force acting between the mover and the stator in the direction perpendicular to the stator are the same member. Therefore, the load force on the movable element guide means can be reduced without increasing the weight of the movable element. In addition, there is no mutual interference between the magnetic flux related to the thrust of the mover and the magnetic flux related to reducing the load force acting on the mover guide means, and the reduction of the load force reduces the thrust of the mover. No effect. Therefore, the linear motor of the present invention is a linear motor that can reduce the load force on the mover guide means while maintaining high acceleration, has quiet operating noise, and has a long guide means life, and has high reliability and It can be widely applied to recorders, plotters, etc. that require long life and quiet operation. Further, by adopting a method in which a guide rail is provided along the stator and the guide rail is sandwiched between at least three pairings on both sides, the movable element is guided along the stator. All the mechanisms can be placed on one side of the mover, and the stator can be effectively placed in the space on the other side of the mover, allowing for a structure that shortens the length of the magnetic path created by the mover and stator. It is. Therefore, leakage of magnetic flux can be reduced, and a reduction in motor thrust due to leakage of magnetic flux can be alleviated.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a conventional example, Fig. 2 is a perspective view of essential parts of the first embodiment of the present invention, Figs. 3 a and b are a front view and sectional view thereof, Figs. 4 and 5 are diagrams for explaining the method of assembling the stator, Figures 6a, b,
7c is a schematic diagram for explaining the operating principle of the first embodiment of the present invention, FIGS. 7a and 7b are a front view and a side view of the main part of the second embodiment of the invention, and FIG. FIG. 6 is a diagram showing an example of a drive current waveform in the second embodiment of the present invention. 11... Stator, 11a, 11b... Inner surface of stator, 11c, 11d, 11e, 11f...
Stator member, 12... Stator magnetic pole teeth, 13... Core, 14... Mover magnetic pole teeth, 15... Permanent magnet,
16... Pairing support member, 17... Pairing, 18... Guide rail, 19... Side plate, 20, 20'... Pairing, 21... Auxiliary plate, 23... Spring, 22... Shaft ,
24a, 24b, 24c... excitation winding, 25a,
25b, 25c...Field part, 26...First core, 27...Second core, 28...First mover magnetic pole tooth, 29...Second mover magnetic pole tooth, 30a,
30b, 30c, 31a, 31b, 31c...field section, 32a, 32b, 32c...excitation winding.

Claims (1)

[Scope of Claims] 1. The movable element is configured to be able to move relative to the stator via a guide means, and the movable element has first magnetic pole teeth that are uneven at a constant pitch in the longitudinal direction of the stator. a first member made of a magnetic material including a plurality of magnetic field portions, each of which has a plurality of field portions formed on each end face; and a plurality of magnetic field portions each wound around the plurality of field portions of the first member. and a permanent magnet that is fixed in close contact with a surface of the first member opposite to the surface on which the first magnetic pole teeth are formed, and that is magnetized in a direction perpendicular to the fixed surface. The stator has a substantially U-shaped cross section perpendicular to its longitudinal direction, is arranged to surround the movable element, and has a predetermined contact with the first magnetic pole tooth of the movable element. The first room of
and a predetermined second space between the surface of the movable element opposite to the surface on which the first magnetic pole teeth are formed.
a magnetic material member, in which irregular second magnetic pole teeth are formed at a constant pitch in the longitudinal direction on a surface opposite to the surface on which the first magnetic pole teeth of the movable element are formed; The guiding means includes first means for maintaining first and second distances between the movable element and the stator, and second means for longitudinally guiding the movable element along the stator. A linear motor characterized by: 2. The first means of the guide means directly maintains the first distance between the surface on which the second magnetic pole teeth of the stator are formed and the surface on which the first magnetic pole teeth of the mover are formed. By doing so, the first pairing means that indirectly maintains the second pairing means and the first pairing means that supports this
The second means of the guide means is provided at at least one of the two ends of the stator, which has a substantially U-shaped cross section perpendicular to the longitudinal direction. A guide rail, a second pairing means arranged to engage with the guide rail so as to guide the movable element along the stator, and a second pairing support mechanism for supporting the second pairing means. A linear motor according to claim 1, characterized in that: