A linear motor, an electromagnetic suspension and a vehicle

Abstract

The present application discloses a linear motor, an electromagnetic suspension and a vehicle. The linear motor includes a primary iron core, a secondary assembly and a position sensor. The primary iron core is an annular structure with a hollow cavity; the secondary assembly is connected to the primary iron core and the two can move relative to each other along a first direction; the position sensor has a first component and a second component; one of the first component and the second component is connected to the primary iron core, and the other is connected to the secondary assembly; at least a part of the first component and / or the second component is disposed in the hollow cavity.

Description

Technical Field

[0001] This application relates to the technical field of driving devices, and more specifically, to a linear motor, an electromagnetic suspension, and a vehicle. Background Art

[0002] A linear motor is a motor that directly converts electrical energy into linear motion mechanical energy without passing through any intermediate conversion device. It can eliminate the intermediate conversion mechanism, reduce the space occupied by the equipment, and improve the system efficiency. As a structural form of the linear motor, the cylindrical linear motor has more advantages; for example, the cylindrical linear motor has high operating efficiency, high power and force density, and good servo performance.

[0003] In the prior art, the cylindrical linear motor still has deficiencies; for example, the arrangement of the sensors is not reasonable enough, which will increase the overall size of the motor. Therefore, it is necessary to propose a new technical solution to improve the structure of the cylindrical linear motor. Summary of the Invention

[0004] An object of this application is to provide a new technical solution for a linear motor, an electromagnetic suspension, and a vehicle.

[0005] According to a first aspect of this application, a linear motor is provided, which includes:

[0006] A primary iron core, the primary iron core being an annular structure with a hollow cavity;

[0007] A secondary assembly, the secondary assembly being connected to the primary iron core and being relatively movable along a first direction therebetween;

[0008] A position sensor, the position sensor having a first component and a second component;

[0009] One of the first component and the second component is connected to the primary iron core, and the other is connected to the secondary assembly;

[0010] At least a part of the first component and / or the second component is disposed in the hollow cavity.

[0011] Optionally, the linear motor includes a primary assembly, the primary assembly including the primary iron core and a primary core shaft, the primary core shaft being sleeved in the hollow cavity.

[0012] Optionally, the primary core shaft is a hollow structure with an accommodation cavity, and at least a part of the first component and / or the second component is disposed in the accommodation cavity.

[0013] Optionally, the first component is a sensor head, and the sensor head is disposed in the accommodation cavity of the primary core shaft.

[0014] Optionally, the position sensor further includes a sensor lead wire. A wire passing hole is provided on the primary iron core, and the sensor lead wire is led out from the sensor head and passes through the wire passing hole.

[0015] Optionally, the primary mandrel includes a mandrel body and a supporting portion. The mandrel body is sleeved in the hollow cavity;

[0016] The supporting portion is fixedly connected to one end of the mandrel body and extends radially outward of the mandrel body; at least part of the primary iron core is supported on the supporting portion.

[0017] Optionally, the sensor head is disposed at a position corresponding to the supporting portion in the accommodating cavity.

[0018] Optionally, the material of the primary mandrel is a magnetic conductive material.

[0019] Optionally, the second component is a magnetic grating bar;

[0020] The linear motor further includes a guide rod; one end of the guide rod is fixedly connected to the secondary assembly, and the other end of the guide rod is disposed in the accommodating cavity;

[0021] The magnetic grating bar is disposed on the side wall of the guide rod. The sensor head and the magnetic grating bar are spaced apart in a second direction, and the second direction is the radial direction of the primary mandrel.

[0022] Optionally, the minimum distance between the sensor head and the magnetic grating bar in the second direction is less than or equal to 5 mm.

[0023] Optionally, the magnetic grating bar is disposed on the outer surface of the side wall of the guide rod; or, the guide rod is a hollow structure, and the magnetic grating bar is disposed on the inner surface of the side wall of the guide rod.

[0024] Optionally, the guide rod is coaxially disposed with the primary mandrel, and the primary mandrel is coaxially disposed in the hollow cavity of the primary iron core.

[0025] Optionally, the material of the guide rod and the material of the housing of the sensor head are both magnetic isolation materials.

[0026] Optionally, the secondary assembly includes a cylindrical housing and magnetic steel disposed on the inner side wall of the housing.

[0027] According to a second aspect of the present application, there is provided an electromagnetic suspension, and the electromagnetic suspension includes the linear motor as described in the first aspect.

[0028] According to a third aspect of the present application, there is provided a vehicle, and the vehicle includes the electromagnetic suspension as described in the second aspect.

[0029] The technical solution adopted in this application can achieve the following beneficial effects:

[0030] In the linear motor provided in the embodiment of this application, the hollow cavity of the primary iron core provides space for the installation and relative movement of at least part of the structure of the position sensor. This helps to reduce the size of the linear motor and make the overall structure of the linear motor more compact.

[0031] Other features and advantages of this application will become clear through the following detailed description of the exemplary embodiments of this application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings incorporated in and constituting a part of this specification illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0033] Figure 1 is an overall structural schematic diagram of a primary component according to an embodiment of this application;

[0034] Figure 2 is a structural schematic diagram of a primary iron core in a primary component according to an embodiment of this application;

[0035] Figure 3 is a cross-sectional structural schematic diagram of a linear motor according to an embodiment of this application.

[0036] Description of the reference numerals:

[0037] 1. Primary component; 10. Primary core shaft; 100. Accommodating cavity; 101. Core shaft body; 102. Supporting part; 11. Primary iron core; 111. First iron core; 1111. Body part; 1112. Positioning part; 1113. Accommodating groove; 1114. Threading hole; 112. Second iron core; 113. Third iron core; 110. Hollow cavity; 12. Coil; 13. Separator; 131. Bottom wall; 132. Cylindrical side wall; 133. Outer edge;

[0038] 2. Secondary component; 21. Housing; 211. Housing bottom; 22. Magnet; 23. First shock pad; 24. Second shock pad; 3. Position sensor; 31. First component; 32. Second component; 300. Sensor lead; 4. Guide rod. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] Now, various exemplary embodiments of this application will be described in detail with reference to the accompanying drawings. It should be noted that: Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of this application.

[0040] The following description of at least one exemplary embodiment is merely illustrative and in no way restrictive of the present application or its application or use.

[0041] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the specification.

[0042] In all examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values.

[0043] It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0044] As Figures 1 - 3 shown, according to an embodiment of the present application, a linear motor is provided. The linear motor includes a primary iron core 11, a secondary assembly 2, and a position sensor 3. The primary iron core 11 is an annular structure having a hollow cavity 110.

[0045] The secondary assembly 2 is connected to the primary iron core 11 and the two can move relative to each other in a first direction. The position sensor 3 has a first component 31 and a second component 32.

[0046] One of the first component 31 and the second component 32 is connected to the primary iron core 11, and the other is connected to the secondary assembly 2. Specifically, one of the first component 31 and the second component 32 is fixedly connected to the primary iron core 11, and the other is fixedly connected to the secondary assembly 2.

[0047] The first component 31 and the second component 32 move relative to each other, and the first component 31 and the second component 32 cooperate with each other to sense the position change between the secondary assembly 2 and the primary iron core 11. At least a part of the first component 31 and / or the second component 32 is disposed in the hollow cavity 110.

[0048] In the linear motor provided by the embodiment of the present application, relative movement can occur between the primary iron core 11 and the secondary assembly 2. This relative movement is a translational movement along the axial direction of the primary iron core 11, and the axial direction of the primary iron core 11 is the above-mentioned first direction.

[0049] For example, the primary iron core 11 is a stator, that is, the primary iron core 11 is fixed; while the secondary assembly 2 is a mover, that is, the secondary assembly 2 moves translationally relative to the primary iron core 11.

[0050] To detect the relative positional relationship of the translational movement between the primary iron core 11 and the secondary assembly 2, the linear motor is provided with a position sensor 3, and the position sensor 3 has a first component 31 and a second component 32. While the secondary assembly 2 and the primary iron core 11 perform relative translational movement, the first component 31 and the second component 32 also perform relative translational movement.

[0051] In the linear motor provided in the embodiment of the present application, at least a part of the first component 31 and / or the second component 32 of the position sensor 3 is arranged in the hollow cavity 110 of the primary iron core 11. That is to say, the hollow cavity 110 provides the installation and relative movement space for at least part of the structure of the position sensor 3, which helps to reduce the size of the linear motor and make the overall structure of the linear motor more compact.

[0052] As Figures 1 - 3 shown, in one embodiment, the linear motor includes a primary assembly 1, and the primary assembly 1 includes the primary iron core 11 and a primary core shaft 10, and the primary core shaft 10 is sleeved in the hollow cavity 110. For example, the primary core shaft 10 is sleeved in the hollow cavity 110 of the primary iron core 11 by an interference fit method; the material of the primary iron core 11 is a soft magnetic material, such as iron-based alloy, cobalt-based alloy, silicon steel and other materials.

[0053] In some embodiments, the primary core shaft 10 is a hollow structure with a receiving cavity 100, and at least a part of the first component 31 and / or the second component 32 is arranged in the receiving cavity 100.

[0054] In this specific example, the primary core shaft 10 is arranged as a hollow structure with a receiving cavity 100, which can not only reduce the material used for manufacturing the primary core shaft 10 and reduce the weight of the primary core shaft 10; moreover, the receiving cavity 100 of the primary core shaft 10 provides the space for accommodating at least part of the structure of the first component 31 and / or the second component 32, making the overall structure of the linear motor more compact.

[0055] For example, the first component 31 is a sensor head, and the sensor head is arranged in the receiving cavity 100 of the primary core shaft 10. Therefore, the first component 31 is indirectly fixedly connected to the primary iron core 11 through the primary core shaft 10; the first component 31 is specifically fixedly connected to the primary core shaft 10, and the primary core shaft 10 is fixedly connected to the primary iron core 11.

[0056] A part of the second component 32 extends into the receiving cavity 100 of the primary core shaft 10. That is to say, the receiving cavity 100 provides a certain stroke for the translational movement of the second component 32 relative to the first component 31 in the first direction. Therefore, the size of the linear motor in the first direction can be saved.

[0057] In one embodiment, the position sensor 3 further includes a sensor lead 300. A wire passing hole 1114 is provided on the primary iron core 11, and the sensor lead 300 is led out from the sensor head and passes through the wire passing hole 1114.

[0058] In this specific example, the wire passing hole 1114 provided on the primary iron core 11 provides a space for the sensor lead 300 to route, thereby making the structure of the linear motor more compact and reasonable.

[0059] As Figures 1 - 3 shown, in one embodiment, the primary core shaft 10 includes a core shaft body 101 and a supporting portion 102. The core shaft body 101 is sleeved in the hollow cavity 110;

[0060] The supporting portion 102 is fixedly connected to one end of the core shaft body 101 and extends radially outward of the core shaft body 101; at least part of the primary iron core 11 is supported on the supporting portion 102.

[0061] In this specific example, a supporting portion 102 is fixedly connected to the outside of the core shaft body 101 of the primary core shaft 10. The supporting portion 102 has an annular structure and is arranged around the core shaft body 101.

[0062] In addition, the primary iron core 11 of the primary component 1 is sleeved outside the core shaft body 101. During the relative movement of the primary component 1 and the secondary component 2, the supporting portion 102 plays a role in supporting the primary iron core 11. The supporting portion 102 can prevent the primary iron core 11 from undergoing unnecessary relative displacement along the axial direction relative to the primary core shaft 10, thereby ensuring the performance of the linear motor.

[0063] As Figure 3 shown, in one embodiment, the sensor head is disposed at a position corresponding to the supporting portion 102 within the accommodation cavity 100. By disposing the sensor head at the end position of the primary core shaft 10 having the supporting portion 102, it does not occupy the stroke of the linear motor, making the arrangement of the position sensor 3 more reasonable.

[0064] In some embodiments, the sensor head as the first component 31 is connected to the primary core shaft 10 of the primary component 1. When the primary component 1 is a stator, the first component 31 is fixed; while the second component 32 is connected to the secondary component 2. When the secondary component 2 is a mover, the second component 32 moves translationally together with the secondary component 2.

[0065] In one embodiment, the material of the primary core shaft 10 is a magnetic conductive material.

[0066] In this specific example, the primary mandrel 10 is made of a magnetic conductive material, such as iron-containing materials like structural steel, die steel, and No. 10 steel. Since the sensor head is arranged in the accommodation cavity 100 of the primary mandrel 10, making the primary mandrel 10 of a magnetic conductive material can improve the performance of this linear motor. If there is a magnetic field leakage in the primary assembly 1, the leaked magnetic field can be conducted away through the primary mandrel 10 made of a magnetic conductive material, thereby protecting the sensor head arranged in the accommodation cavity 100 of the primary mandrel 10 from interference and ensuring the accuracy of the measurement result of the position sensor 3.

[0067] As Figure 3 shown, in one embodiment, the second component 32 is a magnetic grating bar; the linear motor further includes a guide rod 4; one end of the guide rod 4 is fixedly connected to the secondary assembly 2, and the other end of the guide rod 4 is arranged in the accommodation cavity 100;

[0068] the magnetic grating bar is arranged at the side wall of the guide rod 4, the sensor head and the magnetic grating bar are arranged at an interval along a second direction, and the second direction is the radial direction of the primary mandrel 10.

[0069] In this specific example, the position sensor 3 is completely arranged inside this linear motor. Specifically, the first component 31 is connected to the primary mandrel 10 of the primary assembly 1. Also, since the secondary assembly 2 is sleeved outside the primary assembly 1, that is, the primary assembly 1 is located inside the secondary assembly 2, the first component 31 of the position sensor 3 is also located inside the secondary assembly 2.

[0070] Moreover, the second component 32 is arranged at the side wall of the guide rod 4, and a part of the guide rod 4 extends into the accommodation cavity 100 of the primary mandrel 10. Therefore, the second component 32 is also located inside the secondary assembly 2. Therefore, the arrangement of the position sensor 3 will not increase the overall external dimension of this linear motor, and the overall structure of this linear motor is more compact.

[0071] In addition, the first component 31 and the second component 32 are arranged at an interval along the radial direction of the primary mandrel 10 to provide the distance required for mutual induction measurement between the first component 31 and the second component 32.

[0072] In one embodiment, the minimum distance between the sensor head and the magnetic grating bar along the second direction is less than or equal to 5 mm.

[0073] In this specific example, the minimum distance between the first component 31 and the second component 32 is less than or equal to 5 mm, which can ensure the measurement accuracy of the position sensor 3 and ensure that the measurement result of the position sensor 3 is relatively accurate and has a small error.

[0074] In one embodiment, the magnetic grating strip is disposed on the outer surface of the sidewall of the guide rod 4; alternatively, the guide rod 4 is of a hollow structure, and the magnetic grating strip is disposed on the inner surface of the sidewall of the guide rod 4.

[0075] In this specific example, since the first component 31 of the position sensor 3 is a sensor head and the second component 32 of the position sensor 3 is a magnetic grating strip. The magnetic grating strip has a relatively large dimension in the first direction, that is, a longer length, so it is more suitable for being disposed on the sidewall of the guide rod 4, making the arrangement of the position sensor 3 more reasonable.

[0076] For example, the magnetic grating strip is disposed on the outer surface of the sidewall of the guide rod 4; alternatively, the guide rod 4 is set to be of a hollow structure, and the magnetic grating strip is disposed on the inner surface of the sidewall of the guide rod 4.

[0077] In one embodiment, the material of the guide rod 4 and the material of the housing of the sensor head are both magnetic isolation materials.

[0078] In this specific example, the outer shell of the sensor head and the guide rod 4 are both made of magnetic isolation materials. If there is a magnetic field leakage inside the linear motor, the magnetic isolation materials can prevent the magnetic field leaked from inside the linear motor from being conducted to the vicinity of the position sensor 3 and affecting the measurement result of the position sensor 3. Therefore, using magnetic isolation materials to make the outer shell of the sensor head and the guide rod 4 can ensure the accuracy of the measurement result.

[0079] In one embodiment, the secondary component 2 includes a cylindrical housing 21 and a magnetic steel 22 disposed on the inner sidewall of the housing 21.

[0080] In one embodiment, the guide rod 4 is coaxially disposed with the primary core shaft 10, and the primary core shaft 10 is coaxially disposed in the hollow cavity 110 of the primary iron core 11.

[0081] In this specific example, the guide rod 4, the primary core shaft 10, the primary iron core 11 and the housing 21 are all coaxially disposed, so that the structure of the linear motor is more compact and the linear translation effect is better.

[0082] In some embodiments, the primary iron core 11 includes a plurality of first iron cores 111, second iron cores 112 and third iron cores 113;

[0083] The second iron core 112 is disposed away from the supporting portion 102, the third iron core 113 is disposed close to the supporting portion 102, and the plurality of first iron cores 111 are stacked in the first direction and located between the second iron core 112 and the third iron core 113.

[0084] In one embodiment, the cross-section of the magnetic grating strip is semi-circular.

[0085] In this specific example, the magnetic grating strip has a semi-circular cross-section. This can ensure that during the operation of the linear motor, if there is a slight relative rotation between the magnetic grating strip and the sensor head, the magnetic grating strip and the sensor head can still cooperate with each other to detect position information.

[0086] In one embodiment, two magnetic grating strips are provided, and the two magnetic grating strips are symmetrically arranged relative to the guide rod 4; the sensor heads are arranged in one-to-one correspondence with the magnetic grating strips.

[0087] In this specific example, two magnetic grating strips and two sensor heads are provided, and the magnetic grating strips and the sensor heads are in one-to-one correspondence. That is, two pairs of magnetic grating strips and sensor heads are provided, which can improve the reliability of the measurement of the position sensor 3; for example, when one pair of magnetic grating strips and sensor heads fails, the measurement can still be carried out relying on the other pair of magnetic grating strips and sensor heads.

[0088] In one embodiment, both of the two magnetic grating strips extend along a first direction and the lengths of the two magnetic grating strips along the first direction are equal;

[0089] One of the two magnetic grating strips includes M first magnetic poles, and the other includes N second magnetic poles, and the length of the first magnetic pole along the first direction is greater than the length of the second magnetic pole along the first direction.

[0090] In this specific example, the total lengths of the two magnetic grating strips are the same, but the lengths of the individual magnetic poles included in the two magnetic grating strips are different. For example, the two magnetic grating strips are a first magnetic grating strip and a second magnetic grating strip respectively, where the first magnetic grating strip includes M first magnetic poles with longer lengths, and the second magnetic grating strip includes N second magnetic poles with shorter lengths.

[0091] Since the curves of magnetic poles of the same length reflected on the signal are the same, if only the first magnetic grating strip is used for measurement, it will be impossible to know which first magnetic pole in the first magnetic grating strip is the specific position; similarly, if only the second magnetic grating strip is used for measurement, it will be impossible to know which second magnetic pole in the second magnetic grating strip is the specific position. Therefore, it is necessary to use the first magnetic grating strip and the second magnetic grating strip simultaneously, and the two magnetic grating strips cooperate with each other for accurate measurement.

[0092] Moreover, there is no multiple relationship between the length of the first magnetic pole and the length of the second magnetic pole; for example, the length of the first magnetic pole is 5 and the length of the second magnetic pole is 2.

[0093] As Figure 3 shown, in one embodiment, the secondary component 2 includes a housing 21, the housing 21 is cylindrical, and the housing 21 is sleeved outside the primary component 1;

[0094] A first shock pad 23 is provided on the inner side wall of the housing 21. When the secondary assembly 2 and the primary assembly 1 move relatively downward along the first direction, the first shock pad 23 abuts against the supporting portion 102 to limit the downward movement of the secondary assembly 2.

[0095] In this specific example, the first shock pad 23 provided on the inner side wall of the housing 21 of the secondary assembly 2 can limit the downward movement of the secondary assembly 2. That is, during the process of the secondary assembly 2 moving downward relative to the primary assembly 1, the supporting portion 102 hits the first shock pad 23 for limiting, preventing the separation between the primary assembly 1 and the secondary assembly 2.

[0096] As Figure 3 shown, in one embodiment, the secondary assembly 2 further includes a magnet 22. The magnet 22 is sleeved on the inner side of the housing 21, and the first shock pad 23 is located at the bottom of the magnet 22 facing the supporting portion 102.

[0097] In this specific example, the first shock pad 23 is specifically provided at the bottom of the magnet 22 facing the supporting portion 102, so as to ensure that the first shock pad 23 can provide an effective protection effect for the magnet 22 during the movement of the secondary assembly 2.

[0098] As Figure 3 shown, in one embodiment, a second shock pad 24 is provided on the inner side of the bottom 211 of the housing 21. When the secondary assembly 2 and the primary assembly 1 move relatively upward along the first direction, the second shock pad 24 abuts against the supporting portion 102 to limit the upward movement of the secondary assembly 2.

[0099] In this specific example, the second shock pad 24 provided on the inner bottom surface of the housing 21 can limit the upward movement of the secondary assembly 2. That is, during the process of the secondary assembly 2 moving upward relative to the primary assembly 1, the supporting portion 102 hits the second shock pad 24 for limiting, preventing the separation between the primary assembly 1 and the secondary assembly 2.

[0100] In addition, the first iron core 111 includes a main body portion 1111 and a positioning portion 1112. The positioning portion 1112 is provided on the main body portion 1111, and the positioning portion 1112 is a convex structure on one side of the main body portion 1111, and the positioning portion 1112 is a concave structure on the other side of the main body portion 1111;

[0101] Two adjacent first iron cores 111 are connected through their respective positioning portions 1112, and the positioning portion 1112 of one first iron core 111 is embedded and connected in the positioning portion 1112 of the other first iron core 111.

[0102] The main body 1111 is provided with a receiving groove 1113 for accommodating the winding coil 12 , and a threading hole 1114 is provided in the receiving groove 1113 . The threading hole 1114 is used for passing the wires of the winding coil 12 and the sensor lead 300 .

[0103] In addition, a partition 13 is disposed in the accommodating cavity 100 of the primary mandrel 10 , and the partition 13 includes a bottom wall 131 , a cylindrical side wall 132 disposed around the bottom wall 131 , and an outer edge 133 disposed around the cylindrical side wall 132 ;

[0104] The cylindrical side wall 132 is extended along the first direction, that is, the extension direction of the cylindrical side wall 132 is the same as the extension direction of the mandrel body 101; and the cylindrical side wall 132 is coaxially arranged with the mandrel body 101;

[0105] The bottom wall 131 is disposed at one end of the cylindrical side wall 132 along the first direction and located inside the cylindrical side wall 132 ; the outer edge 133 is disposed at the other end of the cylindrical side wall 132 along the first direction and located outside the cylindrical side wall 132 .

[0106] A portion of the guide rod 4 and a portion of the magnetic grid strip extend into the cylindrical side wall 132; therefore, the separator 13 of the above structure provides a certain amount of travel for the movement of the guide rod 4 and the magnetic grid strip along the first direction, which is beneficial to reduce the size of the linear motor along the first direction.

[0107] The accommodating chamber 100 is provided as a cooling component for dissipating heat of the linear motor on the side of the partition 13 facing away from the guide rod 4 .

[0108] According to another embodiment of the present application, an electromagnetic suspension is provided, wherein the electromagnetic suspension includes the linear motor as described above.

[0109] According to yet another embodiment of the present application, a vehicle is provided, comprising the electromagnetic suspension as described above.

[0110] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0111] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A linear motor, characterized in that, The linear motor includes: A primary iron core (11) having a hollow cavity (110); A secondary assembly (2) connected to the primary iron core (11) and relatively movable in a first direction therebetween; A position sensor (3) having a first component (31) and a second component (32); A guide rod (4) with one end fixedly connected to the secondary assembly (2) and the other end disposed within the hollow cavity (110); One of the first component (31) and the second component (32) is connected to the primary iron core (11), and the other is connected to the secondary assembly (2) through the guide rod (4); At least a part of the first component (31) and / or the second component (32) is disposed within the hollow cavity (110); The first component (31) is a sensor head, the second component (32) is a magnetic grating bar, and the cross-section of the magnetic grating bar is semi-circular; The linear motor includes a primary assembly (1), the primary assembly (1) includes the primary iron core (11) and a primary core shaft (10), the primary core shaft (10) is sleeved within the hollow cavity (110); the primary core shaft (10) is a hollow structure having a receiving cavity (100), and at least a part of the first component (31) and / or the second component (32) is disposed within the receiving cavity (100).

2. The linear motor according to claim 1, wherein The sensor head is disposed within the receiving cavity (100) of the primary core shaft (10).

3. The linear motor according to claim 2, wherein The position sensor (3) further includes a sensor lead (300), a wire passing hole (1114) is provided on the primary iron core (11), and the sensor lead (300) is led out from the sensor head and passes through the wire passing hole (1114).

4. The linear motor according to claim 2, wherein The primary core shaft (10) includes a core shaft body (101) and a supporting portion (102), the core shaft body (101) is sleeved within the hollow cavity (110); The supporting portion (102) is fixedly connected to one end of the core shaft body (101) and extends radially outward of the core shaft body (101); at least a part of the primary iron core (11) is supported on the supporting portion (102).

5. The linear motor according to claim 4, wherein The sensor head is disposed at a position corresponding to the supporting portion (102) within the receiving cavity (100).

6. The linear motor according to claim 2, wherein The material of the primary core shaft (10) is a magnetic conductive material.

7. The linear motor according to claim 2, wherein The magnetic grating bar is disposed at the side wall of the guide rod (4), the sensor head and the magnetic grating bar are spaced apart in a second direction, and the second direction is the radial direction of the primary core shaft (10).

8. The linear motor according to claim 7, characterized in that, The minimum distance between the sensor head and the magnetic grating bar in the second direction is less than or equal to 5 mm.

9. The linear motor according to claim 7, characterized in that, The magnetic grating bar is disposed on the outer surface of the side wall of the guide rod (4); or, the guide rod (4) is a hollow structure, and the magnetic grating bar is disposed on the inner surface of the side wall of the guide rod (4).

10. The linear motor according to claim 7, characterized in that, The guide rod (4) is coaxially arranged with the primary mandrel (10), and the primary mandrel (10) is coaxially arranged in the hollow cavity (110) of the primary iron core (11).

11. The linear motor according to claim 7, characterized in that, The material of the guide rod (4) and the material of the housing of the sensor head are both magnetic isolation materials.

12. The linear motor according to claim 1, wherein, The secondary component (2) includes a cylindrical housing (21) and a permanent magnet (22) provided on the inner side wall of the housing (21).

13. An electromagnetic suspension, characterized in that, The electromagnetic suspension includes a linear motor as described in any one of claims 1-12.

14. A vehicle, characterized in that, The vehicle includes the electromagnetic suspension as described in claim 13.

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