JP2001078417A - Linear actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency, output, and miniaturization of a linear actuator, by fitting its movable element on the outside of its stator, and by expanding the providing spaces of its permanent magnets to enable the amounts of the magnetic fluxes generated from its permanent magnets to be increased. SOLUTION: A linear actuator has a cylindrical movable element 12 and a cylindrical stator 13 to perform a reciprocal movement in its axial direction. In this case, after fitting the movable element 12 on the outside of the stator 13 via a space 14, there are fastened to the radially disposed tooth portions of the stator 13 eight magnet-sets 40-47, in each of which four permanent magnets 40a-40d are laminated in its axial direction opposite to the surface of the movable element 12 and a coil portion is provided. As a result, the increase of the amount of its magnetic flux is made posssible, in comparison with the constitution of a stator being fitted to the outside of a movable element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear actuator.

[0002]

2. Description of the Related Art Conventional linear actuators include:
The one described in JP-T-8-505038 is known. This linear actuator has a cylinder-shaped mover 1 and a cylinder-shaped stator 2 that are arranged and configured in the concentric telescoping method shown in FIG. The stator 2 has a space 3 dimensioned for substantially frictionless axial movement with respect to the mover 1. The mover 1 interacts dynamically with the stator 2 and converts electrical energy into mechanical energy.

The mover 1 is dumbbell-shaped, and has a ring-shaped magnetic body usually arranged at two intervals. The stator 3
Usually each has four sets of teeth. The teeth each have a plurality of radially spaced poles. 1
One tooth is defined by four poles. A plurality of permanent magnets 4 are installed in one tooth part in the axial direction.
The magnet switches its polarity radially.

[0004] The stator 2 further has four sets of stator windings (not shown). Each stator winding is arranged in a winding slot and mounted on-axis on an associated set of stator poles P. Each stator winding is connected in series, and
A power supply (not shown) is connected to the end, and when energized, an electromagnetic force is generated to operate the linear actuator.

[0005]

However, in the above-mentioned conventional configuration, the amount of current to be supplied is large because the amount of magnetic flux generated by the permanent magnet cannot be sufficiently obtained, and the winding thickness is long due to the limitation of the outer diameter. Problems such as an increase in wire resistance and an increase in copper loss occur.

Here, the winding resistance Ra and the copper loss Wcu are as follows.

Ra = 2 * Np * (L + t) (1) Wcu = Ia ² * Ra (2) where Np is the total number of stator windings, L is stator thickness, and t
Represents a correction value for the teeth width and the coil end, and Ia represents a winding current.

The present invention solves such a conventional problem and arranges a mover outside a stator so that many permanent magnets can be used. Thus, an object of the present invention is to provide a small, highly efficient and high-output linear actuator.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a linear actuator in which a movable element is arranged outside a stator, so that many permanent magnets can be used.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to solve the above-mentioned problems, the present invention provides a stator having a coil portion and a permanent magnet, a movable member having a magnetic portion located outside the stator, and A linear actuator in which the mover reciprocates along the stator due to the interaction between the magnetic flux generated in the portion and the magnetic flux generated in the permanent magnet.

With this configuration, the area in which the permanent magnet can be disposed can be increased, and the amount of magnetic flux generated by the permanent magnet can be increased. Therefore, the thrust generated by the same current increases.

When the same amount of permanent magnets is used, the stator thickness can be reduced, so that the winding resistance can be reduced. Thereby, copper loss can be reduced, so that higher efficiency can be achieved.

As a result, a high-efficiency, high-output linear actuator can be provided. Further, the same output can be downsized.

[0014] Further, there is provided a spring portion connected to the stator, an output shaft supported in a vibration direction of the spring portion, and a mover connected to the output shaft, wherein the output shaft is integrated with the mover. Vibrates. Thereby, the resonance with the spring can be used, and the reciprocating vibration can be more efficiently performed.

Further, the output shaft vibrates inside the stator, and a bearing for supporting the output shaft can be provided inside the stator.

Further, a permanent magnet is arranged on the outer peripheral surface of the stator. This increases the thrust generated by the same current because more permanent magnets can be used. Further, it is possible to reduce the loss due to the leakage magnetic flux generated at both ends of the permanent magnet.

Further, the stator is constructed by combining a plurality of stator components. With this configuration,
Since the share ratio of the winding can be increased, the resistance value can be reduced. In addition, since a winding machine or the like can be used, the time required for winding can be greatly reduced. Further, the width of the slot opening can be reduced. Since the amount of magnetic flux generated by the permanent magnet can be increased,
Thrust generated by the same current is generated more effectively. With these, copper loss can be reduced. As a result, a high-efficiency, high-output linear actuator can be provided. Further, the same output can be downsized.

Further, the stator is constructed by stacking steel plates in the direction of vibration of the mover. Thereby, by laminating using a silicon steel plate or the like, generation of eddy current can be suppressed and iron loss can be reduced. Further, since the laminating direction is the vibration direction of the mover, it can be easily manufactured by laminating cores formed by a press die or the like as in a general rotating machine.

Further, the mover is formed by stacking ring-shaped steel plates in the vibration direction of the mover. Thereby, by laminating using a silicon steel plate or the like, generation of eddy current can be suppressed and iron loss can be reduced. Further, since the laminating direction is the vibration direction of the mover, it can be easily manufactured by laminating cores formed by a press die or the like as in a general rotating machine.

Still further, in a stator having a coil portion in which windings are concentratedly wound for each tooth portion, a permanent magnet is disposed so that a magnetic flux of the permanent magnet flows through the teeth portion, and the permanent magnet is a magnetic flux of the permanent magnet. Are arranged in the axial direction with a positive permanent magnet portion flowing in the positive direction of the teeth portion and a negative permanent magnet portion flowing in the negative direction, and by changing an energizing direction of the coil portion, the positive permanent magnet is changed. By weakening one of the magnetic poles of the portion or the negative permanent magnet portion, and strengthening the other magnetic pole, by switching the energizing direction of the coil portion, before switching the energizing direction, the magnetic pole weakened by the electric magnetic flux The mover provided with the magnetic body portion is a linear actuator that reciprocates and vibrates according to a change in magnetic flux of the teeth portion, in which the magnetic pole that has been strengthened is weakened.
The mover is arranged outside the stator.

Also, by using the linear actuator for a compressor, a compact and highly efficient compressor can be obtained. Furthermore, by using this compressor, a compact and highly efficient air conditioner can be obtained. Furthermore, by using this compressor, a compact and highly efficient refrigerator can be obtained.

[0022]

(Embodiment 1) Embodiment 1 will be described with reference to the drawings. The embodiment described below relates to a linear actuator having eight poles in the radial direction and four poles in the axial direction, but the number of poles is not limited.

The linear actuator according to the first embodiment has the structure shown in FIG.
As shown in (1), a concentric telescoping method has a cylindrical movable element 12 and a cylindrical stator 13 arranged and configured in a concentric telescoping method, and performs correlated axial reciprocating movement.
The mover 12 is located outside the stator 13 and has a space 14 dimensioned for substantially frictionless axial movement relative to the stator 13. The mover 12 dynamically interacts with the stator 13 to convert electrical energy into mechanical energy.

When the movable element 12 is viewed in detail in FIG. 2, the movable element 12 is generally connected to the holder 22 or the like with a gap between the magnetic portions 20 and 21.

The stator 13 will be described in detail with reference to FIG. 1. The stator 13 has teeth arranged at radial intervals. Each tooth part has a magnet set 40 to 4 having four poles in the axial direction on a surface facing the mover 12.
7 is fixed. The magnet set 40 and the like have permanent magnets stacked in the axial direction, and are viewed from the mover 12 side as shown in FIG.
As shown in the figure, the permanent magnets 40a to 40d are provided.

That is, there are eight magnet sets in the stator 13 corresponding to the eight teeth portions, and if the magnet sets have the same axial position, the magnet sets of the main magnets adjacent in the circumferential direction are provided. The magnetic poles are different. That is, the magnet set 41 arranged on the side next to the magnet set 40 is
There is a different polarity to 2.

The linear actuator thus configured generates an electric magnetic flux by energizing the coil portion, and the mover vibrates in the axial direction by interaction with the magnetic flux generated by the permanent magnet. The operation at this time will be described. When the electric magnetic flux generated by energizing the coil portion passes through the teeth portion and flows in the direction of the mover 12, the magnet set 40 attached to the mover facing surface of the teeth portion is moved. Try to pass. At this time, since the magnetic flux directions of the permanent magnets of the magnet set 40 are different in the axial direction, the magnetic flux flowing through the teeth portion is strengthened at the portion where the permanent magnets 40a and 40c are going to pass, and passes through the permanent magnets 40b and 40d. Since the electric magnetic fluxes to be tried have different directions of the magnetic flux, they cancel each other out, and the magnetic flux generated from the teeth portion becomes very small. In other words, the magnetic poles of the teeth portion have a portion where the magnetic flux is strong in the axial direction and a portion where the magnetic flux is weak. Move.

When the energization of the coil portion is switched in the opposite direction, the magnetic flux direction of the electric magnetic flux flowing through the teeth portion is reversed (from the mover to the outer periphery of the core). The parts that were strong (permanent magnets 40a, 40c) are weakened, and conversely, the parts where the magnetic flux was weak in the axial direction of the teeth before switching the energizing direction are strong. As described above, when the strength of the teeth portion changes, the portion to which the mover 12 is attracted changes, so that the mover 12 is attracted to the main magnets 40b and 40d of the teeth portion having strong magnetic flux. Thus, the movable element 12 vibrates by switching the energization.

Although the vibration of the linear actuator according to the present embodiment has been described focusing on the teeth of the magnet set 40, the movers of the magnet sets 41 to 47 vibrate by changing the energizing direction according to the same principle. . However, the magnetic pole directions of the permanent magnets located at adjacent teeth and located at the same position in the axial direction are opposite to each other. Because mover 12
The magnetic flux passing through the teeth and the magnetic body 20,
21 and a magnetic flux loop may be formed.

As shown in FIG. 1 (b),
It can be divided axially into four stator sections 30a to 30d. The magnetic flux flowing through the teeth portion is
21 and the stator pole P, the magnetic flux changes from the minimum magnetic flux φmin to the maximum magnetic flux φmax.

Thus, referring to FIG. 3, in two stator sections, such as stator sections 30a and 30c, the permanent magnet (PM) bundle is positive (N polarity) as shown in FIG. On the other hand, in the other two stator sections such as the stator sections 30b and 30d, the permanent magnetic flux is negative (S polarity) as shown in FIG. The total magnetic flux for each pole P in one stator winding (not shown), as shown in FIG.
+2 (φmax−φmin) and −2 (φmax−φmin)
min).

Referring to FIG. 3 (a), there is shown a permanent magnetic flux positive curve 30ac illustrating the permanent magnetic flux φ in the stator poles as a function of the stroke length of the prime mover. FIG. 3 (b)
Shows the negative curve 30bd of the permanent magnetic flux, while FIG.
Shows a permanent magnetic flux curve 30e illustrating the permanent magnetic flux φ induced in the coil associated with the pole P.

FIG. 3C shows that the PM bundle is zero in the middle of the stroke. Assuming that saturation is negligible, it can be assumed that flux line changes occur as a function of prime mover position. Therefore, assuming a harmonious movement, it is determined as follows.

X = １ ／ (ls × sinw1t) (3) Therefore, the rm of the total induced voltage when eight coils are linked.
The s value is as follows:

Ea = 35.53f1 (φmax−φmin) Nc (4) where Nc is equal to the number of turns of each coil. F1 represents a frequency.

Next, the induced voltage and the resulting electromagnetic force will be examined in detail. The induced voltage is obtained by equation (4).
When the induced emf Ea and armature (or winding) current Ia are in phase, a maximum electromagnetic force is generated. That is, (Pem) max = EaIa (5) Therefore, the linear actuator operates by being connected to the power supply Vs (not shown) and energizing the windings to generate an electromagnetic force.

Here, in the linear actuator of this embodiment, the mover 12 is arranged outside the stator 13. As a result, an area where permanent magnets can be arranged can be increased as compared with a conventional example in which the stator 2 is arranged outside the mover 1 as shown in FIG. Since the amount of induced permanent magnetic flux can be increased, as a result, (φmax−φ
min) increases. Therefore, as is apparent from the above equations (4) and (5), the thrust generated by the same current becomes larger. Further, the same output can be downsized.

Further, when the same amount of permanent magnets is used, the stator thickness L can be reduced as compared with the conventional case. That is, a flat type in which the stator thickness is smaller than the outer diameter (the outer diameter of the stator 2 in the conventional example, the outer diameter of the mover 12 in the present embodiment) can be obtained. Therefore, as is apparent from the equation (1), the winding resistance Ra can be reduced. As a result, the copper loss Wcu can be reduced as shown in the equation (2), so that higher efficiency can be achieved.

As a result, a high-efficiency, high-output linear actuator can be provided. Further, the same output can be downsized.

By using the linear actuator of this embodiment for a compressor, a compact and highly efficient compressor can be obtained. Furthermore, by using this compressor, a compact and highly efficient air conditioner can be obtained. Furthermore, by using this compressor, a compact and highly efficient refrigerator can be obtained.

(Embodiment 2) FIG. 4 is a sectional view showing a linear actuator according to Embodiment 2. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted. In the second embodiment, a housing part 50 connected to the stator 13, a spring part 51 fixed to the housing part, an output shaft 52 supported in the vibration direction of the spring part, and connected to the output shaft, Mover 1 located between arm 13 and housing 50
2, and the output shaft 52 vibrates integrally with the mover 12. Thereby, the mover 12 can utilize the resonance with the spring 51 and can reciprocate more efficiently.

Third Embodiment FIG. 4 is a sectional view showing a linear actuator according to a third embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted. In the third embodiment, the output shaft 52 vibrates inside the stator 13, and the bearing 53 supporting the output shaft can be provided inside the stator. Thereby, downsizing can be realized. In addition, by using the bearing 53, the output shaft 52 can perform more stable reciprocating motion.

(Embodiment 4) FIG. 5A is a sectional view showing a linear actuator according to Embodiment 4. FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted. Example 4
By arranging the permanent magnet set 40 and the like on the outer peripheral surface of the stator 13, more permanent magnets can be used, and the thrust generated by the same current increases. Further, it is possible to reduce the loss due to the leakage magnetic flux generated at both ends of the permanent magnet.

Although the arrangement of FIG. 5A is optimal,
As shown in (b), (c) and (d), the magnet set 40 may be embedded in the stator, or a flat magnet may be used.
Furthermore, there is no problem even if it is divided into a plurality of magnet sets 40 and 48.

(Embodiment 5) FIG. 6 is a view showing a linear actuator according to a fifth embodiment. The linear actuator includes a cylindrical mover 301 and a stator located inside the mover 301. The stator comprises stator components 302a, 302b, 302c, 302d, 3
02e, 3012, 302g, and 302h can be assembled by connecting them annularly. A magnet set 303 is affixed to each of the stator constituent members, and a coil part 304 is obtained by winding a winding around the recess of the stator constituent member 301a. In this way, when the stator is obtained by connecting a plurality of stator components 302a provided with the coil portion 304 and the magnet set 303 in a ring shape, the stator components 302a and 302b are connected by laser welding.

It is possible to perform winding by a winding machine or the like for each of the stator cores such as the stator core constituting member 302a, so that the wire yield of the winding is greatly increased. Therefore, since the resistance value of the winding decreases, the copper loss can be reduced as is apparent from the above equation (1). In addition, since a winding machine or the like can be used, the time required for winding can be greatly reduced. Furthermore, it is not necessary to wind up.

Further, by dividing, the width of the slot opening 305 can be reduced. Thereby, the amount of permanent magnetic flux induced by the magnet set 303 and the like can be increased, and as a result, (φmax−φmin) increases. Therefore, as is apparent from the above equations (3) and (4), the thrust generated by the same current becomes larger. Further, the same output can be downsized.

The stator component 302a shown in FIG.
And the connecting surface between the stator constituent member 302b is linear,
Although the connection is made by welding, other shapes and connection methods (for example, adhesion) may be used.

(Embodiment 6) FIG. 7A is a sectional view showing a linear actuator according to Embodiment 6. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted. Example 6
Is formed by stacking steel plates in the direction of vibration of the mover. Thereby, by laminating using a silicon steel plate or the like, generation of eddy current can be suppressed and iron loss can be reduced. Further, since the laminating direction is the vibration direction of the mover, it can be easily manufactured by laminating cores formed by a press die or the like as in a general rotating machine.

(Embodiment 7) FIG. 7B is a sectional view showing a linear actuator according to Embodiment 7. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted. Example 7
The mover is formed by stacking ring-shaped steel plates in the vibration direction of the mover. Thereby, by laminating using a silicon steel plate or the like, generation of eddy current can be suppressed and iron loss can be reduced. Also, since the lamination direction is the direction of vibration of the mover,
It can be easily manufactured by laminating cores molded by a press die or the like as in a general rotating machine.

[0051]

As is clear from the description of the above embodiment,
According to the first aspect of the present invention, by arranging the mover outside the stator, the area where the permanent magnet can be arranged can be increased, and the amount of magnetic flux generated by the permanent magnet can be increased. Therefore, the thrust generated by the same current increases. When the same amount of permanent magnets is used, the stator thickness can be reduced, so that the winding resistance can be reduced. Thereby, copper loss can be reduced, so that higher efficiency can be achieved. As a result, a high-efficiency, high-output linear actuator can be provided. Further, the same output can be downsized.

Further, in the invention according to claim 2,
The same effect as above can be obtained, and by using a spring, resonance can be used, and reciprocating vibration can be performed more efficiently.

Further, in the invention according to claim 3,
The same effect as described above can be obtained, and the output shaft vibrates inside the stator, so that a bearing for supporting the output shaft can be provided inside the stator. Thereby, downsizing can be realized. Further, by using the bearing, more stable reciprocating motion can be performed.

Further, in the invention according to claim 4,
The same effect as described above can be obtained, and by disposing the permanent magnet on the outer peripheral surface of the stator, more permanent magnets can be used, so that the thrust generated by the same current increases. Further, it is possible to reduce the loss due to the leakage magnetic flux generated at both ends of the permanent magnet.

Further, in the invention according to claim 5,
The same effect as described above can be obtained, and by dividing the stator, the wire ratio of the winding can be increased, so that the resistance value can be reduced. Furthermore, slot open can be reduced. With these, copper loss can be reduced. As a result, a high-efficiency, high-output linear actuator can be provided. Also,
Since a winding machine can be used, the time required for winding can be greatly reduced.

Further, in the invention according to claim 6,
The same effects as above can be obtained, and by stacking the stator with a silicon steel plate or the like, it is possible to suppress the generation of eddy current and reduce iron loss. Further, since the laminating direction is the vibration direction of the mover, it can be easily manufactured by laminating cores formed by a press die or the like as in a general rotating machine. Further, the same effect as described above can be obtained in the invention described in claim 7.

According to the ninth aspect of the present invention, a compact and highly efficient compressor can be obtained by using the linear actuator of the present invention.

Further, according to the tenth aspect of the present invention, a compact and highly efficient air conditioner can be obtained by using the compressor of the above invention.

Further, according to the eleventh aspect of the present invention, a compact and highly efficient refrigerator can be obtained by using the compressor of the present invention.

[Brief description of the drawings]

FIG. 1A is a sectional view of a linear actuator according to a first embodiment of the present invention. FIG. 1B is a view showing the permanent magnet set.

FIG. 2 is a perspective view of the mover.

FIGS. 3A, 3B, and 3C are explanatory diagrams of magnetic flux.

FIG. 4 is a sectional view of a linear actuator according to Embodiments 2 and 3 of the present application.

5A is a sectional view of a stator according to a fourth embodiment of the present invention. FIG. 5B, FIG. 5C, and FIG. 5D are views showing other shapes of the permanent magnet set.

FIG. 6 is a sectional view of a linear actuator according to a fifth embodiment of the present invention.

FIG. 7A is a perspective view showing a part of a stator according to a sixth embodiment of the present invention. FIG. 7B is a perspective view showing a part of a mover according to a seventh embodiment of the present invention.

FIG. 8 is a sectional view showing a conventional linear actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Mover 13 Stator 14 Space 20, 21 Magnetic body 22 Holder 40-48 Magnet set 50 Housing 51 Spring 52 Output shaft 53 Bearing 302a-302h Stator constituent member

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinichiro Kawano 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Sadao Kawahara 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. (reference)

Claims (11)

[Claims] A stator having a coil portion and a permanent magnet; a mover having a magnetic body portion located outside the stator; a magnetic flux generated by the coil portion and a magnetic flux generated by the permanent magnet. A linear actuator in which the mover reciprocates along the stator due to the interaction of And a spring connected to the stator, an output shaft supported in a vibration direction of the spring, and a mover connected to the output shaft, wherein the output shaft is integrally formed with the mover. 2. The linear actuator according to claim 1, wherein the linear actuator vibrates. 3. The linear actuator according to claim 2, wherein the output shaft vibrates inside the stator, and a bearing portion supporting the output shaft is provided inside the stator. 4. The linear actuator according to claim 1, wherein the permanent magnet is disposed on an outer peripheral surface of the stator. 5. The linear actuator according to claim 1, wherein the stator is configured by combining a plurality of stator components. 6. The linear actuator according to claim 1, wherein the stator is formed by stacking steel plates in the direction of vibration of the mover. 7. The linear actuator according to claim 1, wherein the mover is formed by laminating ring-shaped steel plates in the vibration direction of the mover. 8. A stator including a coil portion in which windings are concentratedly wound for each tooth portion, a permanent magnet is disposed so that a magnetic flux of the permanent magnet flows through the teeth portion, and the permanent magnet has a magnetic flux of the permanent magnet. The positive permanent magnet portion that flows in the positive direction of the teeth portion and the negative permanent magnet portion that flows in the negative direction are arranged in the axial direction. By changing the energizing direction of the coil portion, the positive permanent magnet portion is changed. Or, by weakening one of the magnetic poles of the negative permanent magnet portion, and strengthening the other magnetic pole, by switching the energizing direction of the coil portion, before switching the energizing direction, the magnetic pole that has been weakened by the electric magnetic flux is strong. The magnetic pole that has been strengthened becomes weaker. The mover having the magnetic body portion according to the magnetic flux change of the teeth portion is a linear actuator that reciprocates and vibrates, and the mover is located outside the stator. Linear actuator placed in 9. A compressor using the linear actuator according to claim 1. 10. An air conditioner using the linear actuator according to claim 1. 11. A refrigerator using the linear actuator according to claim 1.