Cooling structure of direct-drive permanent magnet synchronous motor

Abstract

The invention belongs to the technical field of permanent magnet motors, and relates to a direct-drive permanent magnet synchronous motor cooling structure, which comprises a stator module, a rotor module and a cooling module, and is characterized in that the stator module comprises double stators which are symmetrically arranged along the axial direction, and a stator bracket of each stator is in sealing connection with a fixed shaft through a double-flange structure to form an axial through sealing air path; the rotor module comprises a rotor support, the rotor support is fixedly connected with the stator support, the stator support is fixedly connected with the fixed shaft in a sealed mode, the cooling module is arranged in the motor to form a cooling path, cold air enters a stator and rotor air gap under the action of negative pressure, and hot air in the motor is cooled and then reaches an external cooler. And after being cooled by the external heat exchange device, the air enters the motor again for cooling air path circulation. Through the motor cooling structure provided by the invention, the problem that each part in the motor cannot be cooled is effectively solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of permanent magnet motors and relates to a cooling structure of a direct-drive permanent magnet synchronous motor. Background Art

[0002] The mining truck is driven by an electric motor to lift it along the track slope to the steps of the crushing station, effectively shortening the transportation distance, reducing fuel consumption and tire wear, lowering the cost and carbon emissions of raw coal transportation, and improving the safety and refined management level of mining trucks.

[0003] Currently, large open-pit coal mines use trucks to transport raw coal and gangue from the pit bottom to the surface via spiral ascending paths. These trucks consume significant amounts of fuel, generating significant amounts of exhaust gas and dust. Furthermore, the long, labor-intensive ascending paths place high demands on truck performance, requiring constant overhaul and maintenance, which can hinder mining operations.

[0004] Due to the high dust content and harsh cooling environment in mining areas, as well as the temperature sensitivity of different motor components, the existing permanent magnet synchronous motor cooling method is unable to effectively cool the various motor components, resulting in the demagnetization of the permanent magnets due to long-term high-temperature operation, causing serious losses.

[0005] In view of this, this invention is proposed. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and propose a direct-drive permanent magnet synchronous motor cooling structure. The cooling module is arranged inside the motor to form a cooling path. Cold air enters the stator and rotor air gap under the action of negative pressure, cools the hot air inside the motor and then reaches the external cooler. After being cooled by the external cooler, it re-enters the motor and performs cooling air circulation, which effectively solves the problem of internal cooling of the motor.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a direct-drive permanent magnet synchronous motor cooling structure, comprising a stator module, a rotor module and a cooling module, wherein:

[0009] The stator module comprises a double stator symmetrically arranged along the axial direction, and the stator bracket of each stator is sealedly connected to the stator shaft (2) through a double flange structure to form an axially penetrating sealed air path;

[0010] The rotor module includes a rotor bracket, the rotor bracket is fixedly connected to the stator bracket, and the stator bracket is fixedly and sealedly connected to the stator shaft;

[0011] The cooling module is arranged inside the motor to form a cooling path. Cold air enters the stator and rotor air gap under the action of negative pressure to cool the internal structure of the motor, and the hot air is cooled by the external heat exchange device and then re-enters the motor to circulate the cooling air path.

[0012] Furthermore, when the cooling module is a cooling air duct, an air inlet is provided at one end of the fixed shaft and an air outlet is provided at the other end, and the internal cavity of the fixed shaft is in communication with the first radial ventilation duct connected to the stator bracket;

[0013] The cooling air duct consists of the following path: cold air circulates through the air inlet → the internal cavity of the stator shaft → the cavity formed by the rotor bracket, the stator bracket and the motor end cover → the stator and rotor air gap → the first radial ventilation duct → the air outlet → the external air cooler.

[0014] Furthermore, the fixed shaft includes an outer shaft and an inner shaft, the outer side of the outer shaft is sealed and fixedly connected to the stator bracket, there is a gap between the outer shaft and the inner shaft, the outer shaft and the inner shaft are connected and fixed through a first radial ventilation channel, and the first radial ventilation channel is also connected to the cavity formed by the stator bracket and the fixed shaft.

[0015] Furthermore, the inner shaft is a hollow shaft structure with one end closed, and multiple groups of first radial ventilation channels are provided along the axial direction of the inner shaft, with the number of first radial ventilation channels in each group being 2-4.

[0016] Furthermore, the outer shaft is a hollow shaft structure with openings at both ends, and three groups of air inlet channels are provided along the circumferential direction of the outer shaft from left to right, with the number of air inlet channels in each group being 4-8.

[0017] Furthermore, when the cooling module is a cooler module, a second radial ventilation duct is provided on the stator, the stator bracket is provided with an axial ventilation hole and a radial cover plate, and a rectangular window is provided on the radial cover plate;

[0018] The cooler module includes four groups of coolers connected in parallel, each group of coolers is embedded in a rectangular window and communicates with the cavity formed by the stator bracket and the stator shaft;

[0019] The cooling air circulation path is: hot air is cooled by the cooler → the cavity formed by the stator shaft and the stator bracket → the axial ventilation hole on the stator bracket → the stator winding end → the stator-rotor air gap → the second radial ventilation duct → the radial cover plate cavity → the cooler circulation, and the cooler is connected to the external radiator.

[0020] Furthermore, rectangular windows are provided at the 3 o'clock and 9 o'clock positions of the radial cover plate.

[0021] Furthermore, the cooler is assembled from a heat exchange core and a cooling fan. The cooler is connected to an external radiator through an inlet pipe and an outlet pipe arranged on the same side. The coolant in the outlet pipe is cooled by the external radiator, and the cooled coolant then enters each heat exchanger through the inlet pipe.

[0022] Furthermore, there are 4 to 16 axial ventilation holes evenly distributed in the circumferential direction of the stator bracket.

[0023] Furthermore, the double flange structure of the stator bracket and the stator shaft form a symmetrical circulating structure.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a direct-drive permanent magnet synchronous motor cooling structure, which adopts a double-flange structure for the stator of a mining hoisting motor and cooperates with the double flange of the fixed shaft to realize the motor air circulation. The double-flange structure improves the fatigue resistance of the stator and fixed shaft connecting bolts, and effectively avoids radial swing of the motor stator; and the air path of the adopted double-stator structure is symmetrically distributed. Through air cooling, the air duct is built into the interior of the motor to form a cooling path. The cold air enters the stator and rotor air gap under the action of negative pressure, cools the hot air inside the motor and reaches the external cooler. After being cooled by the external cooler, it re-enters the motor and performs cooling air circulation, thereby achieving the technical effect of effectively cooling the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the invention.

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0028] Figure 1 This is a diagram showing the overall structure of a motor according to embodiment 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of the distribution of cooling air ducts inside the motor according to Example 1 of the present invention;

[0030] Figure 3 Schematic diagram of the cross-sectional structure of a motor according to embodiment 2 of the present invention;

[0031] Figure 4 This is a schematic diagram of the distribution of the motor internal cooler modules according to embodiment 2 of the present invention;

[0032] Figure 5This is a schematic structural diagram of the cooler module in Example 2 of the present invention.

[0033] Among them, 1-stator bracket; 11-radial cover; 12-rectangular window; 13-second radial ventilation duct; 14-iron core winding 41; 2-fixed shaft; 21-air inlet; 22-air outlet; 23-outer shaft; 24-inner shaft; 231-air inlet channel; 241-first radial ventilation duct; 3-rotor bracket; 4-cooler; 41-heat exchange core; 42-cooling fan; 43-water inlet pipe; 44-water outlet pipe; 5-motor end cover; 6-cable; 7-bearing system. DETAILED DESCRIPTION

[0034] Here, exemplary embodiments will be described in detail, and the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention described in detail in the appended claims.

[0035] The present invention provides a direct-drive permanent magnet synchronous motor cooling structure suitable for use in mining hoist motor cooling. The present invention provides two motor cooling solutions: Solution 1 utilizes the cavity structure formed by the stator and rotor, and the internal cavities of the stator bracket 1 and the stator shaft 2, to form a circulating air path through air duct isolation, achieving motor heat dissipation and simplifying the motor structure; Solution 2 integrates a cooler module into the motor, circulates the air through the motor's internal air path, and cools the hot air generated inside the motor during the circulation process, thereby achieving motor cooling. The motor end cap 5 is sealed and fixed to the stator shaft 2 via a bearing system 7. The motor is connected to a power source via a cable 6 entering from one end of the stator shaft 2 to power the entire motor.

[0036] Specifically, the present invention is described in detail through the following examples.

[0037] Example 1

[0038] This embodiment provides a direct drive permanent magnet synchronous motor cooling structure, referring to Figure 1-2 As shown, this motor cooling structure consists of a rotor module, a stator module, and a cooling air duct, with an air inlet 21 and an air outlet 22 located at each end of the motor's fixed shaft 2. The motor stator adopts a radial ventilation structure. The stator bracket 1 is equipped with a double flange, and the corresponding fixed shaft 2 is equipped with a double flange structure. The stator bracket 1 and the fixed shaft 2 form a closed air duct structure. An air outlet duct is provided inside the fixed shaft 2, and the air outlet duct is connected to the closed cavity formed by the fixed shaft 2 and the stator bracket 1. The closed cavity formed by the air outlet duct and the fixed shaft 2 is the air inlet duct, and an air inlet 21 is provided at the end of the fixed shaft.

[0039] According to an embodiment of the present invention, the stator module includes a double stator symmetrically arranged along the axial direction, and the stator bracket 1 of each stator is sealedly connected to the stator shaft 2 through a double flange structure to form an axially penetrating sealed air path. The rotor module includes a rotor bracket 3, and the rotor bracket 3 and the stator bracket 1 can be fixedly connected by welding, and the stator bracket 1 is fixedly and sealedly connected to the stator shaft 2.

[0040] This embodiment adopts solution 1 for cooling. When the cooling module is a cooling air duct, specifically, an air inlet 21 is provided at one end of the fixed shaft 2 and an air outlet 22 is provided at the other end. The internal cavity of the fixed shaft 2 is connected to the first radial ventilation duct 241 connected to the stator bracket 1.

[0041] According to an embodiment of the present invention, the stator shaft 2 includes an outer shaft 23 and an inner shaft 24. The outer shaft 23 is sealed and fixedly connected to the stator support 1. A gap is formed between the outer shaft 23 and the inner shaft 24. The outer shaft 23 and the inner shaft 24 are connected and fixed by first radial ventilation channels 241. The first radial ventilation channels 241 also communicate with the cavity formed by the stator support 1 and the stator shaft 2. The inner shaft 24 is a hollow shaft structure with one end closed. Multiple groups of first radial ventilation channels 241 are arranged along the axial direction of the inner shaft 24. Each group of first radial ventilation channels 241 has 2-4, preferably 4, or alternatively 2 or 3, first radial ventilation channels are evenly distributed along the circumference of the inner shaft 24. The outer shaft 23 is a hollow shaft structure with both ends open. Three groups of air inlet channels 231 are arranged along the circumference of the outer shaft 23 from left to right. Each group of air inlet channels 231 has 4-8, preferably 4, or alternatively 5, 6, 7, or 8, first radial ventilation channels are evenly distributed along the circumference of the outer shaft 23.

[0042] According to an embodiment of the present invention, the air inlet 21 and the air outlet 22 in this embodiment are respectively connected to the air outlet and the air inlet of the external air cooler, thereby forming a cooling cycle structure.

[0043] The cooling air duct in this embodiment is composed of the following path: cold air circulates through the air inlet 21 → the internal cavity of the stator shaft 2 → the cavity formed by the rotor bracket 3, the stator bracket 1 and the motor end cover 5 → the stator and rotor air gap → the first radial ventilation duct 241 → the air outlet 22 → the external air cooler. Figure 2 The blue arrows represent the cold air flow path, and the red arrows represent the hot air flow path.

[0044] Specifically, the cold air enters the internal cavity of the fixed shaft 2 through the air inlet 21 set at the end of the fixed shaft 2, and enters the cavity formed by the motor end cover 5, the rotor bracket 3, and the stator bracket 1 through the air inlet channel 231 evenly distributed around the circumference of the fixed shaft 2. The cold air enters the stator-rotor air gap under the action of negative pressure, enters the cavity formed by the stator bracket 1 and the stator shaft 2 through the air gap to form hot air, and then enters the air outlet 22 through the first radial ventilation duct 241, and finally reaches the outside of the motor through the air outlet 22. After being cooled by the external air cooler, it re-enters the motor to realize the entire air circuit circulation.

[0045] Example 2

[0046] This embodiment provides a direct-drive permanent magnet synchronous motor cooling structure, specifically a direct-drive permanent magnet synchronous mining hoisting motor air cooler built-in air-water cooling structure, reference Figure 3-5 As shown, this motor cooling structure consists of a rotor module, a stator module, and a cooler module. The motor stator utilizes a radial ventilation structure. The stator bracket 1 is equipped with a double flange, corresponding to the stator shaft 2, which is also equipped with a double flange structure. The stator bracket 1 is provided with axial ventilation holes. A radial cover plate 11 is also provided in the circumferential direction of the stator bracket 1. Rectangular windows 12 are located at 3 and 9 o'clock on the radial cover plate 11. Specifically, there are 4-16 axial ventilation holes evenly distributed along the circumference of the stator bracket 1, with 8 being the preferred number. Alternatively, 4, 12, or 16 axial ventilation holes can be evenly distributed along the circumference of the stator bracket 1.

[0047] According to an embodiment of the present invention, the stator module includes a double stator symmetrically arranged along the axial direction, and the stator bracket 1 of each stator is sealedly connected to the stator shaft 2 through a double flange structure to form an axially penetrating sealed air path. The rotor module includes a rotor bracket 3, and the rotor bracket 3 and the stator bracket 1 can be fixedly connected by welding, and the stator bracket 1 is fixedly and sealedly connected to the stator shaft 2.

[0048] This embodiment adopts solution 2 for cooling. When the cooling module is a cooler module, a second radial ventilation duct 13 is provided on the stator. Specifically, the second radial ventilation duct 13 is provided on the stator core. The stator bracket 1 is provided with axial ventilation holes and a radial cover plate 11. The radial cover plate 11 has a rectangular window 12. The cooler module includes four sets of coolers 4 connected in parallel. Each set of coolers 4 is embedded in a rectangular window 12 and communicates with the cavity formed by the stator bracket 1 and the stator shaft 2.

[0049] According to an embodiment of the present invention, the cooler 4 in this embodiment is assembled from a heat exchange core 41 and a cooling fan 42. The cooler 4 is connected to an external radiator through a water inlet pipe 43 and a water outlet pipe 44 arranged on the same side. The coolant in the water outlet pipe 44 is cooled by the external radiator, and the cooled coolant then enters each heat exchanger 4 through the water inlet pipe 43 to form a cooling cycle.

[0050] The cooling air circulation path in this embodiment is: hot air is cooled by the cooler 4 → the cavity formed by the stator shaft 2 and the stator bracket 1 → the axial ventilation hole on the stator bracket 1 → the end of the stator winding 5 → the stator-rotor air gap → the second radial ventilation duct 13 → the cavity of the radial cover plate 11 → the cooler 4 circulates, and the cooler 4 is connected to the external radiator. Figure 4 The blue arrows represent the cold air flow path, and the red arrows represent the hot air flow path.

[0051] Specifically, the motor features an internal air circulation structure. Under the action of cooler 4, hot air is cooled by the heat exchange core 41 of cooler 4 before entering the cavity formed by the stator bracket 1 and stator shaft 2. It then passes through the stator bracket 1's axial ventilation holes, eight of which are evenly distributed around the circumference, to the winding ends. Cooled air, under negative pressure, enters the stator-rotor air gap. Through this air gap, it enters the second radial ventilation duct 13, forming hot air. This air then enters the cavity of the radial cover plate 11 of the stator bracket 1, where it is cooled by the heat exchange core 41, which is mounted with rectangular windows 12 at 3 and 9 o'clock, completing the entire air circulation cycle.

[0052] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0053] It should be understood that the present invention is not limited to the above description and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A direct-drive permanent magnet synchronous motor cooling structure, characterized in that: It includes a stator module, a rotor module and a cooling module, wherein: The stator module comprises a double stator symmetrically arranged along the axial direction, wherein the stator bracket (1) of each stator is sealedly connected to the stator shaft (2) via a double flange structure, forming an axially penetrating sealed air path; The rotor module comprises a rotor support (3), the rotor support (3) and the stator support (1) are fixedly connected, and the stator support (1) is fixedly and sealedly connected to the stator shaft (2); The cooling module is arranged inside the motor to form a cooling path. Cold air enters the stator and rotor air gap under the action of negative pressure to cool the internal structure of the motor, and the hot air is cooled by the external heat exchange device and then re-enters the motor to circulate the cooling air path.

2. The direct-drive permanent magnet synchronous motor cooling structure according to claim 1, characterized in that: When the cooling module is a cooling air duct, one end of the fixed shaft (2) is provided with an air inlet (21), and the other end is provided with an air outlet (22), and the internal cavity of the fixed shaft (2) is communicated with a first radial ventilation duct (241) connected to the stator bracket (1); The cooling air duct is composed of the following paths: cold air circulates through the air inlet (21) → the internal cavity of the stator shaft (2) → the cavity formed by the rotor bracket (3), the stator bracket (1) and the motor end cover (5) → the stator-rotor air gap → the first radial ventilation duct (241) → the air outlet (22) → the external air cooler.

3. The direct-drive permanent magnet synchronous motor cooling structure according to claim 2, characterized in that: The fixed shaft (2) comprises an outer shaft (23) and an inner shaft (24); the outer side of the outer shaft (23) is sealed and fixedly connected to the stator bracket (1); a gap exists between the outer shaft (23) and the inner shaft (24); the outer shaft (23) and the inner shaft (24) are connected and fixed via a first radial ventilation channel (241); and the first radial ventilation channel (241) is also connected to a cavity formed by the stator bracket (1) and the fixed shaft (2).

4. The direct-drive permanent magnet synchronous motor cooling structure according to claim 3, characterized in that: The inner shaft (24) is a hollow shaft structure with one end closed. A plurality of groups of first radial ventilation channels (241) are provided along the axial direction of the inner shaft (24), and the number of the first radial ventilation channels (241) in each group is 2-4.

5. The direct-drive permanent magnet synchronous motor cooling structure according to claim 3, characterized in that: The outer shaft (23) is a hollow shaft structure with openings at both ends. Three groups of air inlet channels (231) are provided along the circumferential direction of the outer shaft (23) from left to right, and the number of air inlet channels (231) in each group is 4-8.

6. The direct-drive permanent magnet synchronous motor cooling structure according to claim 1, characterized in that: When the cooling module is a cooler module, a second radial ventilation duct (13) is provided on the stator, the stator bracket (1) is provided with an axial ventilation hole and a radial cover plate (11), and a rectangular window (12) is provided on the radial cover plate (11); The cooler module comprises four groups of coolers (4) connected in parallel, each group of coolers (4) being embedded in a rectangular window (12) and communicating with a cavity formed by a stator support (1) and a stator shaft (2); The cooling air circulation path is: hot air is cooled by the cooler (4) → the cavity formed by the stator shaft (2) and the stator bracket (1) → the axial ventilation hole on the stator bracket (1) → the end of the stator winding (5) → the stator-rotor air gap → the second radial ventilation channel (13) → the radial cover plate (11) cavity → the cooler (4) circulation, and the cooler (4) is connected to an external radiator.

7. The direct-drive permanent magnet synchronous motor cooling structure according to claim 6, characterized in that: Rectangular windows (12) are provided at the 3 o'clock and 9 o'clock directions of the radial cover plate (11).

8. The direct-drive permanent magnet synchronous motor cooling structure according to claim 6, characterized in that: The cooler (4) is assembled from a heat exchange core (41) and a cooling fan (42). The cooler (4) is connected to an external radiator through a water inlet pipe (43) and a water outlet pipe (44) arranged on the same side. The coolant in the water outlet pipe (44) is cooled by the external radiator, and the cooled coolant then enters each heat exchanger (4) through the water inlet pipe (43).

9. The direct-drive permanent magnet synchronous motor cooling structure according to claim 6, characterized in that: There are 4 to 16 axial ventilation holes evenly distributed in the circumferential direction of the stator bracket (1).

10. The direct-drive permanent magnet synchronous motor cooling structure according to claim 1, characterized in that: The double flange structure of the stator support (1) and the stator shaft (2) form a symmetrical circulating structure.

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