A direct-indirect composite cooling structure and cooling method for a permanent magnet synchronous linear motor

Abstract

This invention provides a direct and indirect composite cooling structure and method for a permanent magnet synchronous linear motor. The primary structure of the permanent magnet synchronous linear motor includes: a primary iron core, a winding coil wound around the teeth of the iron core, and cooling water pipes. The iron core has teeth and a yoke, with adjacent teeth and yoke forming an iron core slot. Two parallel water channels are formed at the bottom of each iron core slot, and a water channel is formed on the back of the iron core in the longitudinal direction of each tooth. The cross-section of the water channels is semi-elliptical, and the formation of the water channels does not affect the direction of the magnetic lines of force inside the iron core. Cooling water pipes are embedded in the water channels and extend along the channels. This invention achieves direct and indirect composite cooling by installing cooling water pipes at the bottom of the iron core slots and on the back of the iron core, significantly improving heat dissipation efficiency. Simultaneously, the overall structure is simple and the manufacturing process is easy to implement.

Description

Technical Field

[0001] This invention relates to the field of linear motor technology, and in particular to a direct and indirect composite cooling structure and cooling method for a permanent magnet synchronous linear motor. Technical Background

[0002] With the continuous upgrading of performance requirements for drive equipment in fields such as industrial automation and precision manufacturing, high thrust density permanent magnet synchronous linear motors have become the preferred choice for core drive components due to their advantages such as zero transmission backlash, rapid response, and stable thrust output. To further improve the thrust density of motors, the industry generally optimizes the design by increasing the winding current density. However, this measure directly leads to a sharp increase in heat generation during motor operation, and the problem of heat accumulation becomes increasingly prominent, placing unprecedentedly stringent requirements on the heat dissipation efficiency, temperature control accuracy, and long-term reliability of the cooling system.

[0003] Currently, cooling technologies for permanent magnet synchronous linear motors are mainly divided into two categories: indirect cooling and direct cooling. However, both have unavoidable technical shortcomings and cannot meet the comprehensive requirements of high thrust density motors. Common indirect cooling methods, such as setting up water-cooled channels in the motor housing, require heat transfer through multiple heat transfer interfaces, including the winding insulation layer, core slot walls, core body, and housing. This lengthy heat transfer path significantly increases thermal resistance, making it difficult to quickly dissipate heat. This not only causes a significant temperature rise inside the motor but also easily leads to localized overheating hotspots in core areas such as the winding coils and core teeth, severely affecting the motor's operational stability. While direct cooling allows the cooling medium to directly contact the heat source, greatly shortening the heat transfer path and improving heat dissipation efficiency, this method places extremely high demands on the corrosion resistance of the winding insulation layer and the system's sealing performance. During long-term operation, problems such as insulation layer damage and cooling medium leakage are prone to occur, leading to motor short-circuit faults and posing serious safety and durability challenges to equipment operation.

[0004] Clearly, a single cooling method faces a dilemma where efficient heat dissipation and safety / reliability are mutually exclusive. It cannot simultaneously achieve efficient heat dissipation and temperature uniformity, nor can it guarantee the long-term operational safety of the system. This technical bottleneck has severely restricted the performance breakthroughs and application expansion of high-thrust-density permanent magnet synchronous linear motors. Therefore, there is an urgent need for an innovative cooling structure to effectively and synergistically improve heat dissipation performance and operational reliability within the limited motor installation space. Summary of the Invention

[0005] This invention addresses the core deficiencies of existing technologies by proposing a direct-indirect composite cooling structure and method. Direct cooling pipes are installed at the bottom of the core slots, enabling close contact between the cooling medium and the winding coils, significantly shortening the Joule heat transfer path and reducing thermal resistance. Simultaneously, indirect cooling pipes are installed on the back of the core to specifically absorb heat generated by core losses, preventing heat accumulation and reverse conduction. Combined with a semi-elliptical cooling pipe design, integrated molding of high thermal conductivity materials, and gap filling with high thermal conductivity silicone grease, the heat exchange area and thermal conductivity are maximized, achieving synchronous and efficient heat dissipation between the windings and the core. This structure avoids the stringent requirements for sealing and insulation inherent in direct cooling alone, while solving the problems of high thermal resistance and uneven heat dissipation associated with indirect cooling. While ensuring structural simplicity and manufacturing feasibility, it significantly improves the overall heat dissipation efficiency and temperature uniformity of the motor, providing crucial technical support for performance breakthroughs in high-thrust-density permanent magnet synchronous linear motors.

[0006] The technical solution adopted in this invention is as follows:

[0007] A direct-indirect composite cooling structure for a permanent magnet synchronous linear motor, comprising:

[0008] Primary iron core (1): It has multiple iron core slots arranged in a straight line, and the iron core slots contain winding coils (2).

[0009] Bottom water channel: At the bottom of each iron core slot, two independent water channels with semi-elliptical cross sections are opened along the extension direction, and their positions correspond to the winding coil (2) in the vertical direction.

[0010] Back water channel: On the back of the longitudinal iron core corresponding to each iron core tooth, there is a water channel with a semi-elliptical cross-section.

[0011] Direct cooling pipe (3) and indirect cooling pipe (4): The direct cooling pipe (3) with a semi-elliptical cross section is nested in the water channel at the bottom of the tank, and the indirect cooling pipe (4) with a semi-elliptical cross section is nested in the water channel at the back of the iron core.

[0012] Circulation loop: The direct cooling pipe (3) and the indirect cooling pipe (4) are respectively provided with independent inlet and outlet or shared integrated inlet and outlet, and are connected by pipe joints to form a closed circulation cooling loop. The circulation loop is provided with a seal to prevent leakage of cooling medium.

[0013] Furthermore, the direct cooling pipe (3) and the indirect cooling pipe (4) are integrally formed by 3D printing using high thermal conductivity metal materials, and the whole is distributed in a continuous S-shape.

[0014] Furthermore, the direct cooling pipe (3) and the indirect cooling pipe (4) are composed of alternating straight sections and curved connecting sections, wherein the bending angle of the curved connecting section is 90 degrees.

[0015] Furthermore, the gaps between the water channel and the direct cooling pipe (3) and the indirect cooling pipe (4), the gaps between the direct cooling pipe (3) and the winding coil (2), and the gaps between the indirect cooling pipe (4) and the winding coil (2) are all filled with high thermal conductivity silicone grease.

[0016] Furthermore, the specific dimensional proportions of the water channels satisfy the following: the two water channels in each iron core slot are symmetrically distributed about the center line of the iron core slot, and the total length of the cross section accounts for 1 / 2 to 2 / 3 of the length of the bottom surface of the iron core slot.

[0017] The centerline of the water channel on the back of each iron core coincides with the centerline of the iron core tooth, and the total length of its cross section accounts for 1 / 2 to 2 / 3 of the width of the corresponding tooth.

[0018] The cross-sectional height of the water channel is 1 / 4 to 1 / 3 of the height of the primary iron core yoke.

[0019] Furthermore, the cooling water pipes are arranged in the primary iron core (1) in either a single-pipe series layout or a multi-pipe parallel layout. When a single-pipe series layout is adopted, the cooling water pipes pass through all the bottom water channels and back water channels in sequence, and the inlet and outlet are respectively set at the same end or both ends of the primary iron core (1). When a multi-pipe parallel layout is adopted, a manifold and a branch pipe are set, and the multiple cooling water pipes correspond to different tank groups.

[0020] Furthermore, the end slot of the primary iron core (1) has only one water channel for the cooling water pipe to pass through, and the bottom of the other non-end iron core slots are provided with the above two independent water channels, and the cross-sectional dimensions of the two water channels are the same.

[0021] Furthermore, the high thermal conductivity metal material is selected from copper alloy, aluminum alloy or stainless steel, and the 3D printed cooling water pipe has a microchannel cavity structure inside to increase the local heat exchange area.

[0022] Furthermore, the planar sides of the direct cooling pipe (3) and the indirect cooling pipe (4) are closely attached to the surface of the winding coil (2) or the iron core to maximize the contact heat conduction area.

[0023] A direct-indirect combined cooling method for a permanent magnet synchronous linear motor, characterized by comprising the following steps:

[0024] Step S1: The cooling medium is pumped into the inlet using an external pumping system;

[0025] Step S2: The cooling medium flows in the direct cooling pipe (3) at the bottom of the slot to directly absorb the Joule heat generated by the winding coil (2); at the same time, the cooling medium flows in the indirect cooling pipe (4) at the back to absorb the heat generated by the core loss through the back of the core.

[0026] Step S3: After absorbing heat, the cooling medium flows out through the outlet, enters the external heat dissipation device to complete heat exchange, and then re-enters the circulation. The supply of cooling medium is adjusted according to changes in motor load to control the internal operating temperature of the motor. The beneficial effects of this invention are as follows:

[0027] 1. Significantly improved heat dissipation efficiency: The innovative design combines the advantages of direct and indirect cooling. Through the dual water channel layout at the bottom of the slot and the back of the iron core, as well as the semi-elliptical cooling water pipe design, the cooling contact area is increased and the thermal resistance is reduced. Compared with a single cooling mode, the heat dissipation efficiency is greatly improved, and the heat generated by the winding and iron core is quickly dissipated.

[0028] 2. More uniform temperature distribution: The dual cooling pipes work together to cool the winding coils directly through the cooling water pipes at the bottom of the slots, and absorb the heat conducted by the iron core through the cooling water pipes on the back of the iron core, effectively avoiding local overheating inside the motor and achieving a uniform temperature distribution throughout the machine.

[0029] 3. Enhanced operational reliability and durability: It avoids the stringent requirements of direct cooling on winding insulation and system sealing, while solving the problem of high thermal resistance in indirect cooling. It reduces the risk of seal failure and insulation aging during long-term operation, and improves the stability and service life of the motor.

[0030] 4. Increased thrust and power density: Efficient heat dissipation allows for higher current density windings. Combined with the cooling structure to ensure the strength of the iron core structure, the thrust and power density of the motor are significantly increased within a limited space, meeting the application requirements of high thrust density motors. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 This is a schematic diagram of the core structure of the present invention;

[0033] Figure 3 This is a schematic diagram of the winding coil structure in this invention;

[0034] Figure 4 This is a schematic diagram of the cooling water pipe structure for direct cooling in this invention;

[0035] Figure 5 This is a schematic diagram of the cooling water pipe structure for indirect cooling in this invention;

[0036] Figure 6This is a schematic diagram of the magnetic field lines distribution of the iron core in this invention.

[0037] The components include: 1. Primary iron core; 2. Winding coil; 3. Directly cooled cooling water pipe; 4. Indirectly cooled cooling water pipe. Detailed Implementation

[0038] The specific embodiments of the present invention will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] This example implements a direct and indirect composite cooling structure and cooling method for a permanent magnet synchronous linear motor, including a primary iron core 1, a winding coil 2, a directly cooled cooling water pipe 3, and an indirectly cooled cooling water pipe 4.

[0040] A direct-indirect composite cooling structure for a permanent magnet synchronous linear motor, comprising:

[0041] Primary iron core 1: It has multiple iron core slots arranged in a straight line, and the iron core slots contain winding coils 2, such as... Figure 2 , Figure 3 As shown;

[0042] Bottom water channel: At the bottom of each iron core slot, two independent water channels with semi-elliptical cross-sections are opened along the extension direction, and their positions correspond to the winding coil 2 in the vertical direction.

[0043] Back water channel: On the back of the longitudinal iron core corresponding to each iron core tooth, a water channel with a semi-elliptical cross-section is opened. The bottom of the channel and the location and structural design of the back water channel do not affect the normal direction of the magnetic lines of force inside the iron core. Figure 6 As shown;

[0044] Direct cooling pipe 3, indirect cooling pipe 4, such as Figure 4 , Figure 5 As shown, the direct cooling pipe 3 with a semi-elliptical cross-section is nested in the water channel at the bottom of the tank, and the indirect cooling pipe 4 with a semi-elliptical cross-section is nested in the water channel on the back of the iron core.

[0045] Circulation loop: The direct cooling pipe 3 and the indirect cooling pipe 4 are respectively provided with independent inlet and outlet or shared integrated inlet and outlet, and are connected by pipe joints to form a closed circulation cooling loop. The circulation loop is provided with a seal to prevent the cooling medium from leaking.

[0046] Furthermore, the direct cooling pipe 3 and the indirect cooling pipe 4 are integrally formed by 3D printing using a high thermal conductivity metal material, and the whole is distributed in a continuous S-shape.

[0047] Furthermore, the direct cooling pipe 3 and the indirect cooling pipe 4 are composed of alternating straight sections and curved connecting sections, wherein the bending angle of the curved connecting section is 90 degrees.

[0048] Furthermore, the gaps between the water channel and the direct cooling pipe 3 and the indirect cooling pipe 4, the gaps between the direct cooling pipe 3 and the winding coil 2, and the gaps between the indirect cooling pipe 4 and the winding coil 2 are all filled with high thermal conductivity silicone grease.

[0049] Furthermore, the specific dimensional proportions of the water channels satisfy the following: the two water channels in each iron core slot are symmetrically distributed about the center line of the iron core slot, and the total length of the cross section accounts for 1 / 2 to 2 / 3 of the length of the bottom surface of the iron core slot.

[0050] The centerline of the water channel on the back of each iron core coincides with the centerline of the iron core tooth, and the total length of its cross section accounts for 1 / 2 to 2 / 3 of the width of the corresponding tooth.

[0051] The cross-sectional height of the water channel is 1 / 4 to 1 / 3 of the height of the primary iron core yoke.

[0052] Furthermore, the cooling water pipes are arranged in the primary iron core 1 in either a single-pipe series layout or a multi-pipe parallel layout. When a single-pipe series layout is adopted, the cooling water pipes pass through all the bottom water channels and the back water channels in sequence, and the inlet and outlet are respectively set at the same end or both ends of the primary iron core 1. When a multi-pipe parallel layout is adopted, a manifold and a branch pipe are set, and the multiple cooling water pipes correspond to different groups of tanks.

[0053] Furthermore, the end slot of the primary iron core 1 has only one water channel for the cooling water pipe to pass through, while the bottom of the other non-end iron core slots is provided with the above two independent water channels, and the cross-sectional dimensions of the two water channels are the same.

[0054] Furthermore, the high thermal conductivity metal material is selected from copper alloy, aluminum alloy or stainless steel, and the 3D printed cooling water pipe has a microchannel cavity structure inside to increase the local heat exchange area.

[0055] Furthermore, the planar sides of the direct cooling pipe 3 and the indirect cooling pipe 4 are closely attached to the surface of the winding coil 2 or the iron core to maximize the contact heat conduction area.

[0056] A direct-indirect combined cooling method for a permanent magnet synchronous linear motor, characterized by comprising the following steps:

[0057] Step S1: The cooling medium is pumped into the inlet using an external pumping system;

[0058] Step S2: The cooling medium flows in the direct cooling pipe 3 at the bottom of the slot, directly absorbing the Joule heat generated by the winding coil 2; at the same time, the cooling medium flows in the indirect cooling pipe 4 at the back, absorbing the heat generated by the core loss through the back of the core.

[0059] Step S3: After absorbing heat, the cooling medium flows out through the outlet and enters the external heat dissipation device to complete heat exchange before re-entering the circulation. The supply of cooling medium is adjusted according to changes in motor load to control the internal operating temperature of the motor.

[0060] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any modifications may be made.

Claims

1. A direct-indirect composite cooling structure for a permanent magnet synchronous linear motor, characterized in that, The structure includes: Primary iron core (1): It has multiple iron core slots arranged in a straight line, and the iron core slots contain winding coils (2). Bottom water channel: At the bottom of each iron core slot, two independent water channels with semi-elliptical cross sections are opened along the extension direction, and their positions correspond to the winding coil (2) in the vertical direction. Back water channel: On the back of the longitudinal iron core corresponding to each iron core tooth, there is a water channel with a semi-elliptical cross-section. Direct cooling pipe (3) and indirect cooling pipe (4): The direct cooling pipe (3) with a semi-elliptical cross section is nested in the water channel at the bottom of the tank, and the indirect cooling pipe (4) with a semi-elliptical cross section is nested in the water channel at the back of the iron core. Circulation loop: The direct cooling pipe (3) and the indirect cooling pipe (4) are respectively provided with independent inlet and outlet or shared integrated inlet and outlet, and are connected by pipe joints to form a closed circulation cooling loop. The circulation loop is provided with a seal to prevent leakage of cooling medium.

2. The direct-indirect composite cooling structure for a permanent magnet synchronous linear motor according to claim 1, characterized in that, The direct cooling pipe (3) and the indirect cooling pipe (4) are integrally formed by 3D printing using high thermal conductivity metal materials, and the whole is distributed in a continuous S-shape.

3. The direct-indirect composite cooling structure for a permanent magnet synchronous linear motor according to claim 1, characterized in that, The direct cooling pipe (3) and the indirect cooling pipe (4) are composed of alternating straight sections and curved connecting sections, wherein the bending angle of the curved connecting section is 90 degrees.

4. The direct-indirect composite cooling structure for a permanent magnet synchronous linear motor according to claim 1, characterized in that, High thermal conductivity silicone grease is filled in the gap between the water channel and the direct cooling pipe (3) and the indirect cooling pipe (4), the gap between the direct cooling pipe (3) and the winding coil (2), and the gap between the indirect cooling pipe (4) and the winding coil (2).

5. The direct and indirect cooling structure for a permanent magnet synchronous linear motor according to claim 1, characterized in that, The specific dimensional proportions of the water channels satisfy the following: the two water channels in each iron core slot are symmetrically distributed about the center line of the iron core slot, and the total length of the cross section accounts for 1 / 2 to 2 / 3 of the length of the bottom surface of the iron core slot. The centerline of the water channel on the back of each iron core coincides with the centerline of the iron core tooth, and the total length of its cross section accounts for 1 / 2 to 2 / 3 of the width of the corresponding tooth. The cross-sectional height of the water channel is 1 / 4 to 1 / 3 of the height of the primary iron core yoke.

6. The direct-indirect composite cooling structure for a permanent magnet synchronous linear motor according to claim 1, characterized in that, The cooling water pipes are arranged in the primary iron core (1) in either a single series layout or a multi-parallel layout. When a single series layout is adopted, the cooling water pipes pass through all the bottom water channels and back water channels in sequence, and the inlet and outlet are respectively set at the same end or both ends of the primary iron core (1). When a multi-parallel layout is adopted, a manifold and a branch pipe are set, and the multiple cooling water pipes correspond to different groups of tanks.

7. The direct-indirect composite cooling structure for a permanent magnet synchronous linear motor according to claim 1, characterized in that, The primary core (1) has only one water channel groove at the end for the cooling water pipe to pass through, and the bottom of the other non-end core grooves are provided with the above two independent water channels, and the cross-sectional dimensions of the two water channels are the same.

8. The direct-indirect composite cooling structure for a permanent magnet synchronous linear motor according to claim 2, characterized in that, The high thermal conductivity metal material is selected from copper alloy, aluminum alloy or stainless steel, and the 3D printed cooling water pipe has a microchannel cavity structure inside to increase the local heat exchange area.

9. The direct-indirect composite cooling structure for a permanent magnet synchronous linear motor according to claim 1, characterized in that, The direct cooling pipe (3) and the indirect cooling pipe (4) are closely attached to the surface of the winding coil (2) or the iron core to maximize the contact heat conduction area.

10. A direct-indirect composite cooling method for permanent magnet synchronous linear motors, applicable to the direct-indirect composite cooling structure for permanent magnet synchronous linear motors as described in claims 1-9, characterized in that, Includes the following steps: Step S1: The cooling medium is pumped into the inlet using an external pumping system; Step S2: The cooling medium flows in the direct cooling pipe (3) at the bottom of the slot to directly absorb the Joule heat generated by the winding coil (2); at the same time, the cooling medium flows in the indirect cooling pipe (4) at the back to absorb the heat generated by the core loss through the back of the core. Step S3: After absorbing heat, the cooling medium flows out through the outlet and enters the external heat dissipation device to complete heat exchange. After cooling down to the inlet temperature range, it re-enters the circulation. The supply of cooling medium is adjusted according to the changes in motor load to control the internal operating temperature of the motor.

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