CN216819676U - Linear motor and rotor thereof - Google Patents

Abstract

The application discloses linear electric motor and active cell thereof, the active cell includes core winding subassembly, core winding subassembly includes: a plurality of mover cores each in the form of a comb-shaped sheet, and the plurality of mover cores) are stacked one on another to define a plurality of teeth spaced from one another along a linear moving direction of the mover; a plurality of mover windings wound on teeth of the plurality of teeth except for at least one outermost tooth along the linear movement direction; a hole formed in one of the outermost teeth; and the power cable is inserted and fixed in the hole and is electrically connected with the plurality of rotor windings.

Description

Linear motor and rotor thereof

Technical Field

The present invention relates generally to a mover for a linear motor and a linear motor equipped with the mover, thereby achieving an improvement in thrust density of the linear motor.

Background

With the more mature technology of the linear motor, the application field of the linear motor is wider and wider, and the requirement on the linear motor is higher and higher. Thrust density is one of performance indexes for measuring the linear motor, and more attention is paid to the thrust density, especially to occasions with requirements on volume and thrust.

A linear motor generally includes a stator and a mover arranged with an air gap isolated with respect to the stator and linearly movable with respect to the stator when energized. In the current design of linear motors, one method for increasing the thrust density is to reduce the air gap between the mover and the stator of the linear motor as much as possible, but the reduction of the air gap is limited, and a lower air gap means that the mover and the stator are more likely to scrape each other, and the requirements on the dimensional accuracy of the linear motor itself and the dimensional accuracy and strength of the mechanical structure for mounting the linear motor are higher. Therefore, in the existing linear motor design, when the air gap size is small to a certain extent, it will not be further reduced (e.g. not less than 0.5 mm), otherwise the risk of further reducing the air gap is much larger than the benefit.

In the current design of the linear motor, another method for improving the thrust density is to adjust parameters such as the number of winding turns of the stator to obtain a suitable back electromotive force per unit linear speed, so as to improve the thrust generated by a unit current, thereby further improving the thrust density of the linear motor. However, this method is limited and guaranteed by the maximum allowable operating speed, so that the number of turns of the limiting coil cannot be increased all the time, and further, the improvement of the thrust density of the linear motor is limited.

In addition, in the current design of the linear motor, another method is to increase the lamination thickness of the rotor core relative to the non-outgoing side of the stator in the width direction by the rotor on the premise that the electromagnetic design and the air gap size are difficult to break through, so that the thrust density is improved. However, this method has a disadvantage in that since the mover core must be overlapped with the stator magnet in the laminating direction thereof, the mover is displaced in the width direction with respect to the stator, which increases the overall installation space of the linear motor and affects the applicability of the linear motor.

SUMMERY OF THE UTILITY MODEL

In view of the above problems, the present application aims to provide an improved linear motor mover, so that the thrust density can be increased as much as possible or the overall installation space of the linear motor can be reduced as much as possible under the condition that the overall installation space of the linear motor is not changed.

According to an aspect of the present application, there is provided a mover for a linear motor, the mover including a core winding assembly including:

a plurality of mover cores, each of which is in the form of a comb-shaped sheet, and which are stacked one on another to define a plurality of teeth spaced apart from one another along a linear moving direction of the mover;

a plurality of mover windings wound on teeth of the plurality of teeth except for at least one outermost tooth along the linear movement direction;

a hole formed in the outermost tooth;

and the power cable is inserted and fixed in the hole and is electrically connected with the plurality of rotor windings.

According to an embodiment of the application, an extension of the hole is perpendicular to a direction in which the mover cores are stacked on each other.

According to an embodiment of the present application, the mover further includes a sealant surrounding a periphery of the mover core and/or a periphery of a portion of the mover winding located outside the mover core, and the hole is not located in the sealant.

According to an embodiment of the present application, the power cable is electrically connected to the plurality of mover windings in a gap between an outermost tooth formed with the hole and one tooth immediately adjacent to the tooth.

According to an embodiment of the application, the mover has an exposed top mounting surface, a thermal barrier coating material is applied to the mounting surface, the thermal barrier coating material having a thermal conductivity at least two orders of magnitude less than a thermal conductivity of the mover core.

According to an embodiment of the present application, the hole is located near one side of the outermost tooth along a width of the mover among the outermost teeth.

According to an embodiment of the present application, a direction in which the mover cores are stacked on each other is perpendicular to a linear movement direction of the mover.

According to another aspect of the present application, there is provided a linear motor including:

a stator;

a mover mounted linearly movably with respect to the stator, wherein the mover is the aforementioned mover.

According to an embodiment of the present application, the stator is formed with regions aligned with a plurality of mover cores of the mover, the stator has a vertical center plane bisecting the stator in a width direction, the mover has a vertical center plane bisecting the mover in the width direction, and the vertical center plane of the stator and the vertical center plane of the mover are coplanar with each other.

According to an embodiment of the present application, the plurality of mover cores are stacked on each other in a width direction of the mover, and a region of the stator interacts with an electromagnetic thrust that urges the mover to move linearly in a longitudinal direction of the stator after the mover windings of the mover are energized.

According to an embodiment of the application, the linear electric motor is a permanent magnet direct current motor.

By adopting the technical means, the thrust density of the linear motor can be obviously improved, and the adaptability of the linear motor to different application occasions is improved. In addition, in the case where the thrust density is increased, the utilization efficiency of the entire installation space of the linear motor can be further reduced. In addition, the rotor heat dissipation influence of the linear motor is restrained on the premise that the thrust density is improved, so that the linear motor has more flexible and reliable adaptability to the existing application occasions of the linear motor.

Drawings

The principles and aspects of the present application will be more fully understood from the following detailed description, taken in conjunction with the accompanying drawings. It is noted that the drawings may not be to scale for clarity of illustration and will not detract from the understanding of the present application. In the drawings:

figure 1 shows schematically an end view of a prior art linear motor;

FIG. 2 schematically illustrates an end view of a portion of a linear motor according to one embodiment of the present application;

fig. 3A is a top view schematically illustrating a top view of a portion of a linear motor according to an embodiment of the present application;

fig. 3B is a sectional view taken along a line D-D in fig. 3A, schematically illustrating a mover of the linear motor shown in fig. 3A;

fig. 4 is a perspective view schematically illustrating a mover of a linear motor according to an embodiment of the present application, wherein a sealant of the mover is removed for clarity;

fig. 5 is a side view schematically illustrating a mover of a linear motor according to another embodiment of the present application;

fig. 6 is a side view schematically illustrating a mover of a linear motor according to another embodiment of the present application.

Detailed Description

In the various figures of the present application, features that are structurally identical or functionally similar are denoted by the same reference numerals.

Figure 1 schematically shows an end view of a linear motor 10 according to the prior art. The linear motor 10 generally includes a mover 11 and a stator 12, and they are arranged such that an air gap 13 exists between the mover 11 and the stator 12, and the mover 11 is linearly movable relative to the stator 12 due to generation of electromagnetic force upon energization. In fig. 1, a three-dimensional coordinate system XYZ is shown, having three axes X, Y, Z perpendicular to each other, wherein the coordinate axis X represents the width direction of the linear motor 10, the coordinate axis Y represents the height direction of the linear motor 10, and the coordinate axis Z represents the length direction of the linear motor, i.e. the direction in which the mover 11 is linearly movable relative to the stator 12. Typically, the stator 11 comprises a core winding assembly 11a and an encapsulation 11b surrounding the core winding assembly 11 a. The core material winding assembly 11a is constituted by a plurality of core materials (not shown in fig. 1) stacked on each other and windings (not shown in fig. 1) wound as necessary around the stacked core materials by electric wires. For example, the stacking direction of the core materials is a direction along the X axis. In order to supply the electric wires of the windings of the mover 11 with electricity for generating the required electromagnetic action, a power cable 14 is also provided in the mover 11. The power cable 14 is arranged in the area of the sealing compound 11 b.

As can be seen from fig. 1, a region aligned with the core winding assembly 11a is provided in the stator 12 located below, and the width of this region in the X-axis direction is G. On the premise that it is difficult to further reduce the dimension of the air gap 13 in the Y-axis direction, the improvement of the thrust density of the linear motor 10 depends mainly on the magnitude of G. Therefore, in order to leave a sufficient installation space for the power cables 14, the mover 11 is shifted toward the side where the power cables 14 are located along the X-axis direction while maintaining the outer dimensions of the mover 11. This causes the vertical center planes 11c of the movers 11 (which are parallel to the YZ plane) to be offset from each other in the X-axis direction with respect to the vertical center plane 12 of the stator 12 (which is also parallel to the YZ plane). This results in an increase in the mounting dimension of the linear motor 10 as a whole in the X direction on the premise that the width G is constant, that is, on the premise that the dimension of the core winding assembly 11a in the X axis direction is constant. In addition, the amount of the sealant 11b on the side of the mover 11 where the power cable 14 is installed is increased due to the installation requirement of the power cable 14. This may also cause problems with poor heat dissipation at that side.

Figure 2 schematically illustrates an end view of a portion of a linear electric machine 100 according to one embodiment of the present application. In fig. 2, only those key technical features are shown to facilitate understanding of the technical solution of the linear motor 100 of the present application, but it should be apparent to those skilled in the art that other essential components of the linear motor 100 are required in order to realize the operation of the linear motor 100.

The linear motor 100 generally includes a mover 110 and a stator 120. The mover 110 is disposed above the stator 120 with an air gap 130 therebetween. The stator 110 includes a core winding assembly 111 and a sealant 112 surrounding the core winding assembly 111. In fig. 2, a three-dimensional coordinate system XYZ is also shown, which has three axes X, Y, Z perpendicular to each other, wherein coordinate axis X represents the width direction of the linear motor 100, coordinate axis Y represents the height direction of the linear motor 100, and coordinate axis Z represents the length direction of the linear motor 100, i.e. the direction in which the mover 110 is linearly movable relative to the stator 120. The core winding assembly 111 includes a plurality of mover cores 111b stacked on each other in a width direction of the mover 110, i.e., in an X-axis direction shown in the drawing. As further shown in fig. 3B, each mover core 111B is substantially in the form of a comb-shaped plate, for example, having a plurality of teeth spaced from each other in the Z-axis direction.

Basically, the mover cores 111b have an overall width G 'in the X-axis direction after being stacked on each other, the width G' being set such that the mover cores 111b can be aligned with a specific region of the stator 120 located below, for example, the convex region 120 a. When the mover 111 is energized, an electromagnetic action is generated between the mover cores 111b stacked on each other and the regions 120a aligned therewith to cause the mover 110 to move linearly in the Z-axis direction with respect to the stator 120.

Since each of the mover cores 111b is substantially in the form of a comb-shaped sheet, a plurality of teeth portions spaced from each other in the Z-axis direction will be formed between the plurality of mover cores 111b when they are stacked on each other. Each tooth portion is formed by corresponding teeth of each mover core 111b being overlapped with each other. After the mover core materials 111B are stacked on each other, a plurality of mover windings 111a may be formed by winding electric wires around the respective teeth as needed (see fig. 3B). For example, the mover windings 111a may be included to be spaced apart from each other along the Z-axis direction. When the electric lines of these mover windings 111a are energized, electromagnetic energy capable of interacting with the stator 120 will be generated in the mover 110 as needed. Therefore, it is considered that the width G' of the mover core 111b ultimately determines the magnitude of the thrust density of the linear motor 100.

Unlike the related art, the mover cores 111b stacked on each other have holes 113 formed therein. The hole 113 is, for example, a straight hole and extends in a direction parallel to the Z axis. As shown in fig. 3B, the mover core 111B stacked on each other may have a plurality of teeth in which at least one of two outermost teeth opposite to each other in the Z-axis direction is not wound with an electric wire to form a winding. Therefore, in a preferred embodiment, the holes 113 are formed to pass through only one outermost tooth 111c of the mover core 111b, which is not provided with a winding, after being stacked on each other. In manufacturing the mover 110, the respective mover core materials 111b are first laminated on each other, and then electric wires are wound on the formed plurality of teeth (except for the outermost teeth where no winding is provided) accordingly to form the plurality of windings 111 a. Then, as shown in fig. 4, a hole 113 is formed in the outermost tooth 111c where no winding is provided, and may be formed by drilling, for example. Then, the power cable 140 is inserted into the hole 113, and the lead-out wire of each winding 111a is electrically connected to the power cable 140 in the gap between the outermost tooth 111c and the tooth immediately adjacent thereto. This ensures that the sealant does not affect the connection strength between the outgoing line and the power cable 140 (e.g., due to the pressure of the sealant) during the subsequent sealing process. Finally, sealant 112 is applied around the mover core 111b, and after curing, sealant treatment is completed, as shown in fig. 3A. For example, encapsulation can be accomplished in a manner well known in the art. In an alternative embodiment, the sealant 112 is applied cured around the outer circumference of the exposed portions of the mover core 111b and its windings 111a, as viewed in a top view as shown in fig. 3A.

Referring to fig. 2, according to the linear motor 100 of the present application, since the power cable 140 is installed through the hole 113 formed in the mover core 111b, it is not necessary to offset the mover and the stator from each other in the X-axis direction as in the related art. Therefore, when the outer dimensions of the mover 110 or the size of the installation space of the linear motor 100 is constant, the width G' of the stacked mover cores 111b can be increased as much as possible, and the corresponding region 120a of the stator 120 can be increased in size, thereby increasing the thrust density of the linear motor 100. According to the technical solution of the present application, a vertical center plane 110c (which is parallel to a YZ plane) symmetrically bisecting the mover 110 or the mover core materials 111b stacked on each other and a vertical center plane 120c (which is also parallel to a YZ plane) symmetrically bisecting the stators 120 are coplanar. Therefore, when the width G' is increased to increase the thrust density, the amount of the sealant 112 can be reduced as much as possible, thereby improving the heat dissipation effect.

It will be clear to the skilled person that the position of the form of the holes 113 is not limited to the position shown in the figures; in alternative embodiments, the holes 113 may be formed in any desired positions of the outermost teeth 111c of the mover core 111b that are overlapped with each other with respect to the Y-axis and the Z-axis. In an additional or alternative embodiment, in order to prevent any material from being detached near the portion of the corresponding mover core 111b during the process of forming the holes 113, thereby affecting the subsequent inference density, an adhesive may be applied in advance at the portion of each mover core where the holes 113 are to be formed, and after each mover core is stacked and the windings are wound and fixed, there will be no unnecessary detachment of the material of the mover core 111b during the process of reworking the holes 113. After the final sealing treatment, the stacked mover core materials 111b will be firmly fixed without any material separation.

It should be apparent to those skilled in the art that the linear motor 100 of the present application may occupy a smaller installation space than the linear motor 10 of the prior art in comparison with the prior art shown in fig. 1 in which the widths G and G' are the same (i.e., in a case of providing the same thrust density).

The linear motor 100 of the present application may be a permanent magnet linear motor, or any other linear motor suitable for use in the present application. To explain the effects of the present invention, the following description is given with reference to table 1.

TABLE 1

In Table 1, reference numeral 1 denotes conventionalThe conventional linear motor without any improvement in the art is represented by reference numeral 2, which represents a conventional linear motor improved in the prior art in the manner shown in fig. 1, and reference numeral 3, which represents a linear motor improved by the technical solution of the present application. For comparison, the outline volume of the mover in each linear motor is 313.20cm³. Here, the outer volume of the mover refers to the volume occupied by the mover after potting (power cable is removed). In addition, the installation volume in table 1 refers to a volume occupied by the mover of the linear motor and the stator cooperating with the mover together on the premise that a normal function of the linear motor can be achieved. The continuous thrust in table 1 represents the magnitude of the thrust measured in the case where the linear motor is normally operated. Further, in table 1, the calculation formula of the thrust density 1 is: the measured continuous thrust/rotor profile volume; the thrust density 2 is calculated by the formula: the measured continuous thrust/volume.

From the values of table 1, the following table 2 can be obtained.

Table 2 shows the thrust change of the linear motor with serial number 2 relative to serial number 1; and serial No. 3 versus serial No. 1 and 2 linear motor thrust changes. As is apparent from the results in table 2, the linear motor adopting the technical solution of the present application is greatly improved in thrust density compared to the linear motor of the prior art, which is enough to demonstrate that the technical solution of the present application has outstanding substantial progress and significant technical effect compared to the prior art.

In the case of adopting the technical scheme of this application, because the improvement of thrust density will probably cause the calorific value of active cell to increase under same condition. In the application of linear motors with strict heat generation requirements, how to eliminate the heat increase is considered, especially for core linear motors without water cooling effect.

In general, the mover 110 of the linear motor 100 may be provided such that the top surface thereof directly forms a mounting surface 110a for mounting a third party part, as shown in fig. 5. Alternatively, as shown in fig. 6, a mounting bracket 160 for mounting a third party part may be additionally disposed on the top surface of the mover 110 of the linear motor 100. In any way, if the third part directly contacts the mounting surface 110a of the mover 110, the thrust density caused by the technical solution of the present application increases to increase the heat generation amount of the mover 110, which inevitably causes the third part originally designed for the linear motor in the prior art to be heated too much, and further causes the adverse heat dissipation result for the third part, thereby affecting the precision requirement of the application occasion of the linear motor.

In the technical scheme of the application, the core material can be a silicon steel sheet, and the thermal conductivity of the core material is about 30W/(m.K). In order to reduce heat transfer from the mounting surface 110a of the mover 110 to a third party part or the mounting bracket 160, a thermal barrier coating 150 may be applied on the mounting surface 110a of the mover 110. The coating material of the thermal barrier coating 150 is selected to have a significantly lower thermal conductivity system than the core material. Such a thermal barrier coating material may be any suitable coating material commercially available. According to one example, the thermal barrier coating material may be a material having a thermal conductivity of 0.02W/(m K). According to an alternative embodiment, the thermal barrier coating material may also be a commercially available HX-012/2000 type high temperature resistant, thermally conductive coating having a thermal conductivity of up to 0.03W/(m.K); or the heat conductivity coefficient of the ZS-220 type high-temperature resistant heat-conducting coating can reach 0.04W/(m.K).

According to the embodiment of the present application, since the thermal barrier coating material having the thermal conductivity different by several orders of magnitude is applied on the mounting surface 110a of the mover 110, when the third party component or the mounting bracket 160 is mounted on the mounting surface 110a such that the thermal barrier coating 150 is interposed between the third party component or the mounting bracket 160 and the mounting surface 110a, the presence of the thermal barrier coating 150 causes heat to be more uniformly and slowly transferred to the third party component or the mounting bracket 160, and thus the subsequent adverse effect caused by excessive heat dissipation due to the increase of the thrust density can be greatly reduced.

Of course, it should be apparent to those skilled in the art that in order to overcome the above-mentioned adverse effects, in an alternative embodiment, the mounting bracket 160 may be further designed to be mostly spaced apart from the mounting surface 110a of the mover 110 and only a small portion is fixed in contact with the mounting surface 110a of the mover 110, thereby improving a heat dissipation effect.

Although specific embodiments of the present application have been described herein in detail, they have been presented for purposes of illustration only and are not to be construed as limiting the scope of the application. Further, it should be clear to those skilled in the art that the various embodiments described in this specification can be used in combination with each other. Various substitutions, alterations, and modifications may be conceived of without departing from the spirit and scope of the present application.

Claims (11)

1. A mover for a linear electric machine, the mover (110) comprising a core winding assembly (111), characterized in that the core winding assembly (111) comprises:

a plurality of mover cores (111b), each of the mover cores (111b) being in the form of a comb-shaped sheet, and the plurality of mover cores (111b) being stacked one on another to define a plurality of teeth spaced from one another along a linear moving direction of the mover (110);

a plurality of mover windings (111a), the plurality of mover windings (111a) being wound on teeth of the plurality of teeth except for at least one outermost tooth along the linear movement direction;

a hole (113) formed in the outermost tooth;

a power cable (140), wherein the power cable (140) is inserted and fixed in the hole (113) and is electrically connected with the plurality of rotor windings (111 a).

2. The mover according to claim 1, characterized in that the extension of the holes (113) is perpendicular to the direction in which the mover cores (111b) are stacked on each other.

3. The mover according to claim 1 or 2, further comprising a sealant (112) surrounding a circumference of the mover core (111b) and/or a portion of the mover winding (111a) located outside the mover core (111b), wherein the hole (113) is not located in the sealant (112).

4. The mover of claim 3, wherein the power cable (140) is electrically connected to the plurality of mover windings (111a) in a gap between an outermost tooth (111c) formed with the hole (113) and a tooth immediately adjacent to the tooth.

5. The mover of claim 4, wherein the mover (110) has an exposed top mounting surface (110a), and a thermal barrier coating material is applied on the mounting surface (110a), the thermal barrier coating material having a thermal conductivity at least two orders of magnitude less than a thermal conductivity of the mover core (111 b).

6. The mover of claim 5, wherein the hole (113) is located near one side of the outermost tooth (111c) along a width of the mover (110) in the outermost tooth (111 c).

7. The mover according to claim 6, wherein a direction in which the mover cores (111b) are stacked one on another is perpendicular to a linear movement direction of the mover (110).

8. A linear motor, comprising:

a stator (120);

mover (110) linearly movably mounted with respect to the stator (120), characterized in that the mover (110) is a mover (110) according to any of claims 1 to 7.

9. The linear motor according to claim 8, wherein the stator (120) is formed with a region (120a) aligned with a plurality of mover cores (111b) of the mover (110), the stator (120) has a vertical center plane (120c) bisecting it in a width direction, the mover (110) has a vertical center plane (110c) bisecting it in the width direction, and the vertical center plane (120c) of the stator (120) and the vertical center plane (110c) of the mover (110) are coplanar with each other.

10. The linear motor according to claim 9, wherein the plurality of mover cores (111b) are stacked one on another in a width direction of the mover (110), and the regions (120a) of the stator (120) interact with an electromagnetic thrust that urges the mover (110) to linearly move in a longitudinal direction of the stator (120) upon energization of mover windings (111a) of the mover (110).

11. A linear motor according to any one of claims 8 to 10, characterized in that the linear motor (100) is a permanent magnet dc motor.

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