A high-speed embedded permanent magnet synchronous motor rotor structure and its optimization design method

Abstract

A high-speed embedded permanent magnet synchronous motor rotor structure and an optimization design method thereof, comprising a hollow shaft assembly, an end plate, a spray plate, an oil injection assembly, a silicon steel sheet group, and a bearing; forward flow channels and reverse flow channels are formed in the silicon steel sheet group, the hollow shaft assembly, the end plate, and the spray plate; thermal-fluid coupling optimization is performed with the number and relative position of permanent magnets on the embedded rotor as a first optimization target to determine the number and position dimensions of the forward oil channels and the reverse oil channels; thermal-mechanical coupling optimization is performed with the maximum cold transfer and the minimum flow resistance as a second optimization target to determine the structural dimensions of the forward oil channels and the reverse oil channels, and the cooling oil supply rate at different rotation speeds.

Description

Technical Field

[0001] The present invention relates to the technical field of rotor structures and designs thereof, and in particular to a high-speed embedded permanent magnet synchronous motor rotor structure and an optimization design method thereof. Background Art

[0002] As the power of motors increases, the cooling problem of rotors has attracted more and more attention. In particular, the heat dissipation environment of the rotor of embedded permanent magnet synchronous motors is even worse. High temperature will cause the magnetic steel to demagnetize, causing irreversible damage to the rotor. The prior art proposes an oil-cooled rotor structure based on a hollow shaft. By creating oil channels on the shaft and rotor of the motor, the cooling oil is thrown onto the stator core and windings, thereby enhancing the heat dissipation of the motor. However, this technology still has the following problems: 1. Since the magnetic steel of the embedded permanent magnet rotor is embedded in the through holes of several silicon steel sheets, the heat dissipation problem in the middle of the rotor cannot be effectively solved by setting oil channels at the end of the rotor; 2. Due to the high rotor speed, the speed of the cooling oil reaching the end winding is relatively high. Although it can enhance heat dissipation, it will have an impact on the motor winding at high speed. Long-term high impact may cause the winding to deform or even fail.

[0003] Therefore, it is necessary to design a new high-speed embedded permanent magnet synchronous motor rotor structure and its optimization design method, which can effectively cool the rotor ends and middle parts, and at the same time ensure that the impact of the rotating spray cooling oil on the stator winding is reduced regardless of the forward and reverse rotation of the motor. Summary of the invention

[0004] The object of the present invention is to provide a high-speed embedded permanent magnet synchronous motor rotor structure and an optimization design method thereof to solve the technical problems in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A high-speed embedded permanent magnet synchronous motor rotor structure, characterized in that it includes a hollow shaft assembly, an end plate, a spray plate, an oil injection assembly, a silicon steel sheet group, and a bearing; the hollow shaft assembly is internally divided into three parts by a three-stage stepped hole form, wherein the part with the largest aperture is the forward oil injection cavity, the part with the second largest aperture is the reverse oil injection cavity, and the part with the smallest aperture is the hollow cavity; a first partition plate is fixedly installed on the stepped shoulders of the forward oil injection cavity and the reverse oil injection cavity, and a first through hole is opened at the center position of the first partition plate; a second partition plate is fixedly installed on the stepped shoulders between the reverse oil injection cavity and the hollow cavity; two centrally symmetrical forward oil injection holes are opened on the cavity wall of the forward oil injection cavity along the radial direction of the hollow shaft; two centrally symmetrical reverse oil injection holes are also opened on the cavity wall of the reverse oil injection cavity along the radial direction of the hollow shaft, and when observed from the cross section of the hollow shaft assembly, the two forward oil injection holes and the two reverse oil injection holes are 90° out of phase with each other.

[0007] Preferably, the oil filling assembly includes a forward oil filling pipe, a reverse oil filling pipe, and a two-way valve. The forward oil filling pipe and the reverse oil filling pipe extend into the interior of the hollow shaft assembly along the axis of the hollow shaft. The diameter of the forward oil filling pipe is larger than that of the reverse oil filling pipe. The forward oil filling pipe is sleeved on the outside of the reverse oil filling pipe. The forward oil filling pipe extends into the forward oil filling chamber and is stopped. After passing through the forward oil filling chamber, the reverse oil filling pipe passes through the first through hole on the first partition and then extends into the reverse oil filling chamber.

[0008] Preferably, the silicon steel sheet group is sleeved on the outside of the hollow shaft assembly through an interference fit to form the main structure of the rotor. The silicon steel sheet group is stacked by a number of odd or even thin silicon steel sheets. A slot for inserting permanent magnets is opened near the edge of the circular sheet body of the silicon steel sheet group. A spray plate and an end plate are arranged on both sides of the silicon steel sheet group from the inside to the outside. Forward flow channels and reverse flow channels are formed in the silicon steel sheet group, the hollow shaft assembly, the end plate and the spray plate.

[0009] Preferably, the forward-rotating flow channel includes a forward-rotating central flow channel, a spray plate distribution flow channel, a rotor internal flow channel, a permanent magnet cooling flow channel, and a forward-rotating spray flow channel.

[0010] Preferably, the center of each thin silicon steel sheet except the central 1-2 thin silicon steel sheets in the silicon steel sheet group has a central hole for interference fit installation of the hollow shaft assembly, and a positive rotation center flow channel groove is provided on the central hole relative to the two positive rotation oil injection holes of the hollow shaft assembly; the central 1-2 thin silicon steel sheets in the silicon steel sheet group also have a positive rotation center flow channel groove provided on the central hole relative to the two positive rotation oil injection holes of the hollow shaft assembly; the positive rotation center flow channel groove on each thin silicon steel sheet in the silicon steel sheet group constitutes two positive rotation center flow channels running through the silicon steel sheet group, and the positive rotation center flow channels are connected to the positive rotation oil injection cavity through the positive rotation oil injection hole;

[0011] The center of the spray plate has a central through hole for interference fit on the outside of the hollow shaft assembly. The central through hole is surrounded by a circle of annular grooves to form a spray plate distribution channel. An annular boss is provided between the spray plate distribution channel and the central through hole. The thickness of the annular boss is equal to half the height of the forward rotating central flow channel groove.

[0012] Preferably, the internal flow channel of the rotor is formed by interconnecting the internal flow channel holes arranged on each thin silicon steel sheet, the internal flow channel holes on the thin silicon steel sheet are arranged symmetrically, the number of the internal flow channel holes is consistent with the number of permanent magnets on the circumferential direction of the rotor, the center distance of the internal flow channel holes on each thin silicon steel sheet from the center is different, the internal flow channel holes on the thin silicon steel sheets at both ends of the rotor are closest to the center and their aperture range is completely covered within the range of the spray plate distribution flow channel; from both ends to the middle, the internal flow channel holes on the thin silicon steel sheets gradually move away from the center in the radial direction of the same phase, but the internal flow channel holes on adjacent thin silicon steel sheets are still partially connected, forming a plurality of rotor internal flow channels obliquely outward from both ends to the middle inside the rotor; at the same cross-sectional position, two rotor internal flow channels are interconnected in the center of the rotor;

[0013] Each thin silicon steel sheet is provided with a permanent magnet cooling channel hole at a radial position close to the permanent magnet, and the permanent magnet cooling channel holes of two adjacent thin silicon steel sheets are interconnected to form a permanent magnet cooling channel; the number and phase of the permanent magnet cooling channels are the same as the number and phase of the channels inside the rotor; the permanent magnet cooling channels and the channels inside the rotor of the same phase are connected at the thin silicon steel sheet in the center of the rotor;

[0014] The permanent magnet cooling channel extends along the rotor axis to the spray plates at both ends and is connected with the forward-rotating spray channel on the front of the spray plate; the forward-rotating spray channel is a groove arranged on the front of the spray plate, and the number and phase position of the forward-rotating spray channel correspond to the number and phase of the permanent magnet cooling channel one by one; each forward-rotating spray channel is arranged at the edge position of the front of the spray plate, and the forward-rotating spray channel has a forward-rotating spray channel inlet and a forward-rotating spray channel outlet; the forward-rotating spray channel inlet is connected with the permanent magnet cooling channel, and the forward-rotating spray channel outlet is located at the edge of the front of the spray plate; the direction of the rotor's forward rotation is clockwise, and the direction of the forward-rotating spray channel is counterclockwise.

[0015] Preferably, the reversing flow channel includes a reversing central flow channel, a crossing flow channel, a spray plate reversing distribution flow channel, and a reversing spray flow channel; a reversing central flow channel groove is provided on the central through hole of each thin silicon steel sheet in the silicon steel sheet group at a phase position relative to the reversing oil injection hole on the hollow shaft assembly, and the reversing central flow channel groove on each thin silicon steel sheet in the silicon steel sheet group constitutes two upper and lower reversing central flow channels extending axially along the hollow shaft assembly, and the reversing central flow channel is connected to the reversing oil injection cavity through the reversing oil injection hole; the crossing flow channel is provided on the central through hole of the spray plate, and the crossing flow channel is a groove axially extending on the central through hole of the spray plate, and the number and position of the crossing flow channels correspond to the number and position of the reversing central flow channels, and the height of the crossing flow channel is less than the height of the annular boss on the spray plate, and the height of the crossing flow channel is the same as the height of the reversing central flow channel;

[0016] A spray plate reversal distribution channel consisting of an annular groove is arranged at a through hole near the center on the back side of the spray plate, and a plurality of reversal spray channels are radially distributed on the back side of the spray plate; the reversal spray channel has a reversal spray channel inlet and a reversal spray channel outlet, the reversal spray channel inlet is connected to the spray plate reversal distribution channel, and the reversal spray channel outlet is located at the edge of the spray plate; the clockwise direction represents the rotation direction of the back side of the spray plate when the motor rotor reverses, and each reversal spray channel is in an arc shape. For the same reversal spray channel, its reversal spray channel outlet is set counterclockwise relative to the phase of the reversal spray channel inlet.

[0017] An optimization design method for a high-speed embedded permanent magnet synchronous motor rotor structure, characterized in that:

[0018] S1: Taking the number and relative position of permanent magnets on the embedded rotor as the first optimization target, thermal-fluid coupling optimization is performed to determine the number and position size of the forward oil passage and the reverse oil passage;

[0019] S2: Perform thermomechanical coupling optimization with the second optimization goal of maximizing cooling transfer and minimizing flow resistance to determine the structural dimensions of the forward and reverse oil channels and the cooling oil supply rate at different speeds.

[0020] Preferably, the number of forward oil channels and reverse oil channels in S1 is determined according to the number and relative positions of permanent magnets, and the relative positions of the rotor internal flow channels, permanent magnet cooling flow channels, and forward spray flow channels are optimized through thermal-fluid coupling optimization design. At the same time, the relative positions of the permanent magnet cooling flow channels, forward spray flow channels, and permanent magnets are determined through thermal-fluid coupling optimization design according to the number and relative positions of permanent magnets.

[0021] Preferably, the structural dimensions of the forward oil channel and the reverse oil channel in S2 are specifically thermomechanically coupled optimized based on the second optimization objective of maximizing cold transfer and minimizing flow resistance, and the cross-sectional area of ​​the forward center flow channel, the depth and width of the spray plate distribution flow channel, the aperture of the rotor internal flow channel, the aperture of the permanent magnet cooling flow channel, the angle and cross-sectional area of ​​the forward spray flow channel, the cross-sectional area of ​​the reverse center flow channel, the cross-sectional area of ​​the crossing flow channel, the depth and width of the spray plate reverse distribution flow channel, and the angle and cross-sectional area of ​​the reverse spray flow channel are determined; the cooling oil supply rate at different speeds in S2 is specifically thermomechanically coupled optimized based on the second optimization objective of maximizing cold transfer and minimizing flow resistance, and the cooling oil supply rate at different forward and reverse speeds of the motor is determined.

[0022] The beneficial effects of the present invention are:

[0023] 1. By setting a forward flow channel and a reverse flow channel inside the rotor, in the forward state of the motor, the cooling oil is injected into the flow channel between the inner wall of the forward oil filling pipe and the outer wall of the reverse oil filling pipe, enters the forward oil filling cavity, and then enters the forward center flow channel through the forward oil filling hole. The cooling oil flows to both sides in the forward center flow channel and enters the annular spray plate distribution flow channel, and then the cooling oil enters the rotor internal flow channel from both sides. The cooling oil in the two rotor internal flow channels is collected in the center of the silicon steel sheet group and then enters the permanent magnet cooling flow channel, and continues to flow to both sides along the permanent magnet cooling flow channel. After entering the forward spray flow channel on the spray plates on both sides, it is sprayed backward from the forward spray flow channel outlet to the stator winding, thereby realizing the rotor axis, the inside of the rotor, and the stator winding under the forward state of the motor. The permanent magnets, rotor ends and stator windings are fully and effectively dissipated of heat, and the impact of spray cooling oil on the windings is effectively reduced. In the motor reversal state, since the motor reversal speed is usually lower than the forward speed, no rotor internal heat dissipation channel is set during reversal, and only the rotor end is rotated to spray the stator windings. The cooling oil is injected into the reversal oil filling chamber through the reversal oil filling pipe, and then enters the reversal center flow channel through the reversal oil filling hole. Then the cooling oil moves along the reversal center flow channel to the two ends of the rotor to the spray plate, passes through the crossing flow channel on the spray plate, enters the spray plate reversal distribution flow channel on the opposite side of the spray plate, and finally sprays onto the stator windings through the reversal spray flow channel, so that the motor can reduce the impact of cooling oil on the windings under both forward and reverse conditions.

[0024] 2. The present invention also provides a corresponding optimization design method, which optimizes and reduces the inevitable obstruction to the rotation of the rotor caused by the setting of the forward oil channel and the reverse oil channel. In addition, the optimization design method ensures that the cooling oil injected into the forward oil channel and the reverse oil channel can flow evenly around the rotor, and evenly and efficiently dissipate heat for rotors of different sizes and specifications, which plays a key role in the normal operation of the embedded rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the forward flow channel structure of this application;

[0026] Figure 2 It is a schematic diagram of the reverse flow channel structure of the present application;

[0027] Figure 3 This is the schematic diagram of the thin silicon steel sheet structure of this application Figure 1 ;

[0028] Figure 4 This is the schematic diagram of the thin silicon steel sheet structure of this application Figure 2 ;

[0029] Figure 5 This is the front and back structure diagram of the spray plate in this application Figure 1 ;

[0030] Figure 6This is the front and back structure diagram of the spray plate in this application Figure 2 .

[0031] In the figure: hollow shaft assembly 1, end plate 2, spray plate 3, oil injection assembly 4, silicon steel sheet group 5, bearing 6, forward oil injection chamber 11, reverse oil injection chamber 12, first partition plate 13, first through hole 131, second partition plate 14, forward oil injection hole 15, reverse oil injection hole 16, forward oil injection pipe 41, reverse oil injection pipe 42, two-way valve 43, forward central flow channel 5A, spray plate distribution flow channel 31, rotor internal flow channel 5B, permanent magnet cooling flow channel 5C, forward spray flow channel 33, non-central thin silicon steel sheet 51, central thin silicon steel Plate 52, forward center flow channel groove 513, spray plate distribution flow channel 31, annular boss 32, internal flow channel hole 511, permanent magnet cooling flow channel hole 512, through hole 516, forward spray flow channel inlet 332, forward spray flow channel outlet 331, reverse center flow channel 5D, through flow channel 34, spray plate reverse distribution flow channel 351, reverse spray flow channel 352, reverse center flow channel groove 514, reverse spray flow channel inlet 3522, reverse spray flow channel outlet 3521, first key groove 515, second key groove 36. DETAILED DESCRIPTION

[0032] The specific implementation of the present invention is described in detail below with reference to the accompanying drawings and preferred embodiments.

[0033] like Figure 1-2 The figure shows the rotor structure of the high-speed embedded permanent magnet synchronous motor of the present invention, which includes a hollow shaft assembly 1, an end plate 2, a spray plate 3, an oil injection assembly 4, a silicon steel sheet group 5, and a bearing 6. The hollow shaft assembly 1 is rotatably mounted on the motor housing through the bearings 6 at both ends. The hollow shaft assembly 1 is a hollow shaft structure with an opening at one end. The hollow shaft hole inside the hollow shaft assembly 1 is divided into three parts by three-stage stepped holes, wherein the part with the largest aperture is the forward oil injection cavity 11, the part with the second largest aperture is the reverse oil injection cavity 12, and the part with the smallest aperture is the hollow cavity. A first partition plate 13 is fixedly mounted on the stepped shoulders of the forward oil injection cavity 11 and the reverse oil injection cavity 12, and a first through hole 131 is opened at the center of the first partition plate 13. A second partition plate 14 is fixedly mounted on the stepped shoulder between the reverse oil injection cavity 12 and the hollow cavity. Two forward oil injection holes 15 that are symmetrical in center are opened on the cavity wall of the forward oil injection cavity 11 along the radial direction of the hollow shaft. Two centrally symmetrical reverse oil injection holes 16 are also provided on the cavity wall of the reverse oil injection cavity 12 along the radial direction of the hollow shaft. When observed from the cross section of the hollow shaft assembly 1 , the two forward oil injection holes 15 and the two reverse oil injection holes 16 are 90° out of phase with each other.

[0034] The oil injection assembly 4 includes a forward oil injection pipe 41, a reverse oil injection pipe 42, and a two-way valve 43. The oil injection assembly 4 is fixedly mounted on the motor housing, and the forward oil injection pipe 41 and the reverse oil injection pipe 42 extend into the hollow shaft assembly 1 along the axis of the hollow shaft. The diameter of the forward oil injection pipe 41 is larger than that of the reverse oil injection pipe 42. The forward oil injection pipe 41 is sleeved on the outside of the reverse oil injection pipe 42. The forward oil injection pipe 41 extends into the forward oil injection chamber 11 and stops. The reverse oil injection pipe 42 passes through the forward oil injection chamber 11 and then passes through the first through hole 131 on the first partition plate 13 and then extends into the reverse oil injection chamber 12. The two-way valve 43 is installed at the ends of the forward oil injection pipe 41 and the reverse oil injection pipe 42. The two-way valve 43 is controlled by the controller to select the valve path, and the cooling oil is injected into the flow channel between the inner wall of the forward oil injection pipe 41 and the outer wall of the reverse oil injection pipe 42, or the cooling oil is injected into the flow channel inside the inner wall of the reverse oil injection pipe 42, so as to transport the cooling oil to the forward oil injection chamber 11 or the reverse oil injection chamber respectively. In addition, the oil injection assembly 4 also includes a pump, a filtering structure and other devices for supplying cooling oil. A rotating sealing structure is also provided at the entrance position of the forward oil injection pipe 41 and the forward oil injection chamber 11. A rotating sealing structure is also provided between the first partition plate 13 and the reverse oil injection pipe 42. The above devices do not belong to the main inventive concept of the present invention, but also belong to the application of the prior art, and will not be repeated here.

[0035] The silicon steel sheet group 5 is sleeved on the outside of the hollow shaft assembly 1 through an interference fit to form the main structure of the rotor. The silicon steel sheet group 5 is composed of a number of odd or even thin silicon steel sheets stacked together. The silicon steel sheet group 5 is provided with a slot for inserting a permanent magnet near the edge of the circular sheet to form an embedded permanent magnet rotor structure. The specific arrangement form and size of the permanent magnet are selected according to the actual motor parameter requirements and will not be repeated here. A spray plate 3 and an end plate 2 are sequentially arranged at the ends of both sides of the silicon steel sheet group 5 from the inside to the outside (away from the direction of the silicon steel sheet group 5), that is, the silicon steel sheet group 5 is sandwiched between the spray plates 3 on both sides, and an end plate 2 is also arranged on the outside of the spray plate 3.

[0036] The forward flow passage and reverse flow passage of the motor rotor of the present invention are described below.

[0037] First combine Figure 1 , 3 , 4, 5 are used to describe the forward-rotating flow channel of the present invention. The forward-rotating flow channel includes a forward-rotating central flow channel 5A, a spray plate distribution flow channel 31, a rotor internal flow channel 5B, a permanent magnet cooling flow channel 5C, and a forward-rotating spray flow channel 33. Figure 4 The figure shows a schematic diagram of the non-central thin silicon steel sheet 51 in the silicon steel sheet group 5 except for the central 1-2 thin silicon steel sheets. The center of the non-central thin silicon steel sheet 51 has a central hole for interference fit installation of the hollow shaft assembly 1. A positive rotation center flow channel groove 513 is opened on the central hole relative to the two positive rotation oil injection holes 15 of the hollow shaft assembly 1. Similarly, Figure 3As shown, the central 1-2 central thin silicon steel sheets 52 in the silicon steel sheet group 5 are also provided with a positive rotation center flow channel groove 513 on the central hole relative to the two positive rotation oil injection holes 15 of the hollow shaft assembly 1. The positive rotation center flow channel groove 513 on each non-central thin silicon steel sheet 51 and the central thin silicon steel sheet 52 in the silicon steel sheet group 5 constitutes two positive rotation center flow channels 5A running through the silicon steel sheet group 5, and the positive rotation center flow channel 5A is connected to the positive rotation oil injection cavity 11 through the positive rotation oil injection hole 15.

[0038] like Figure 5 The figure shows a schematic diagram of the spray plate 3 being close to the side of the silicon steel sheet group 5, which is hereinafter referred to as the front side. Figure 1 and Figure 4 As shown, the center of the spray plate 3 also has a central through hole for interference fit on the outside of the hollow shaft assembly 1, and a spray plate distribution channel 31 is formed by a circle of annular grooves around the central through hole. An annular boss 32 is provided between the spray plate distribution channel 31 and the central through hole. Figure 1 It can be seen that the thickness (or height) of the annular boss 32 is equal to half the height of the positive rotation center flow channel groove 513, so as to ensure that the cooling oil in the positive rotation center flow channel 5A can flow into the spray plate distribution flow channel.

[0039] The rotor internal flow channel 5B is formed by interconnecting the internal flow channel holes 511 provided on each non-central thin silicon steel sheet 51 and the central thin silicon steel sheet 52. Figure 4 Taking the non-central thin silicon steel sheet 51 as an example, the internal flow channel holes 511 on the non-central thin silicon steel sheet 51 are centrally symmetrically arranged, and the number of the internal flow channel holes 511 is consistent with the number of permanent magnets in the circumferential direction of the rotor. In this embodiment, there are 14 internal flow channel holes 511. Figure 1 It can be seen that the center distance of the internal flow channel holes 511 on each non-central thin silicon steel sheet 51 in the present invention from the center is different. Specifically, the internal flow channel holes 511 on the non-central thin silicon steel sheets 51 at both ends of the rotor are closest to the center, and their aperture range is completely covered within the range of the spray plate distribution channel 31. From the two ends to the middle, the internal flow channel holes 511 on the non-central thin silicon steel sheets 51 gradually move away from the center in the radial direction of the same phase, but the internal flow channel holes 511 on adjacent non-central thin silicon steel sheets 51 remain partially connected, and finally form a plurality of rotor internal flow channels 5B that are obliquely outward from the two ends to the middle inside the rotor. The farthest end of the rotor internal flow channel 5B that is obliquely outward from the center inside the rotor is close to the radial position of the permanent magnet to achieve heat dissipation at the permanent magnet. As shown Figure 1 As shown, at the same cross-sectional position, two rotor internal flow channels 5B penetrate each other in the center of the rotor.

[0040] In addition, each non-central thin silicon steel sheet 51 is provided with a permanent magnet cooling channel hole 512 at a radial position close to the permanent magnet, and the permanent magnet cooling channel holes 512 of two adjacent non-central thin silicon steel sheets 51 are interconnected to form a permanent magnet cooling channel 5C. The number and phase of the permanent magnet cooling channels 5C are the same as the number and phase of the rotor internal channels 5B. The permanent magnet cooling channels 5C and the rotor internal channels 5B of the same phase are connected in the 1-2 central thin silicon steel sheets 52 in the center of the rotor, that is, Figure 3 As shown, the permanent magnet flow channel holes 512 and the internal flow channel holes 511 of the central 1-2 central thin silicon steel sheets 52 in the silicon steel sheet group 5 are connected to form a through hole 516 .

[0041] The permanent magnet cooling channel 5C extends along the rotor axis to the spray plates 3 at both ends and is connected to the forward spray channel 33 on the front of the spray plate 3. The forward spray channel 33 is shaped as follows: Figure 5 As shown, the forward-rotating spray channel 33 is a groove arranged on the front of the spray plate 3, and the number and phase position of the forward-rotating spray channel 33 correspond one-to-one with the number and phase of the permanent magnet cooling channel 5C. Each forward-rotating spray channel 33 is arranged at the edge position of the front of the spray plate 3, and the forward-rotating spray channel 33 has a forward-rotating spray channel inlet 332 and a forward-rotating spray channel outlet 331. The forward-rotating spray channel inlet 332 is connected to the permanent magnet cooling channel 5C, and the forward-rotating spray channel outlet 331 is located at the edge of the front of the spray plate 3. Figure 5 The clockwise direction is the direction of the rotor's forward rotation, and the direction of the forward spray channel 33 is counterclockwise, that is, the forward spray channel outlet 311 is located behind the forward spray channel inlet 332. This arrangement allows the cooling oil to be sprayed from the forward spray channel 33 in the opposite direction of the rotation direction when the spray plate 3 rotates forward, thereby offsetting the speed of the cooling oil sprayed out to reach the stator winding under high-speed rotation, and reducing the impact of the spray cooling oil on the stator winding at high speed.

[0042] When the motor is in the forward rotation state, the cooling oil is injected into the flow channel between the inner wall of the forward rotation oil filling pipe 41 and the outer wall of the reverse rotation oil filling pipe 42, enters the forward rotation oil filling chamber 11, and then enters the forward rotation center flow channel 5A through the forward rotation oil filling hole 15. The cooling oil flows to both sides in the forward rotation center flow channel 5A and enters the annular spray plate distribution flow channel 31. Then the cooling oil enters the rotor internal flow channel 5B from both sides. The cooling oil in the two rotor internal flow channels 5B converges in the center of the silicon steel sheet group 5 and enters the permanent magnet cooling flow channel 5C. It continues to flow to both sides along the permanent magnet cooling flow channel 5C, enters the forward rotation spray flow channel 33 on the spray plates 3 on both sides, and then is sprayed backward from the forward rotation spray flow channel outlet 331 to the stator winding, thereby realizing comprehensive and effective heat dissipation of the rotor axis, the inside of the rotor, the permanent magnets, the rotor ends and the stator windings in the forward rotation state of the motor.

[0043] Combine the following Figure 2 ,3 , 4, and 6 illustrate the reverse flow channel of the present invention.

[0044] like Figure 2 As shown, the reverse flow channel includes a reverse central flow channel 5D, a cross flow channel 34, a spray plate reverse distribution flow channel 351, and a reverse spray flow channel 352. A reverse central flow channel groove 514 is provided on the central through hole of each non-central thin silicon steel sheet 51 and the central thin silicon steel sheet 52 in the silicon steel sheet group 5 at a phase position relative to the reverse oil injection hole 16 on the hollow shaft assembly 1. Therefore, the reverse central flow channel groove 514 on each non-central thin silicon steel sheet 51 and the central thin silicon steel sheet 52 on the silicon steel sheet group 5 constitutes two upper and lower reverse central flow channels 5D extending axially along the hollow shaft assembly 1. The reverse central flow channel 5D is connected to the reverse oil injection cavity 12 through the reverse oil injection hole 16. The through-flow channel 34 is provided on the central through hole of the spray plate 3. The through-flow channel 34 is a groove extending axially on the central through hole of the spray plate 3. The number and position of the through-flow channel 34 correspond to the number and position of the inverted central flow channel 5D. The height of the through-flow channel 34 is less than the height of the annular boss 32 on the spray plate 3, and the height of the through-flow channel 34 is the same as the height of the inverted central flow channel 5D. The through-flow channel 34 guides the cooling oil from the front side of the spray plate 3 to the back side of the spray plate 3 (i.e., the side away from the silicon steel sheet 5).

[0045] like Figure 6 The figure shows the back structure of the spray plate 3. The back through hole near the center of the spray plate 3 is provided with a spray plate reverse distribution channel 351 formed by an annular groove. A plurality of reverse spray channels 352 are radially distributed on the back of the spray plate 3. The reverse spray channel 352 has a reverse spray channel inlet 3522 and a reverse spray channel outlet 3521. The reverse spray channel inlet 3522 is connected to the spray plate reverse distribution channel 351. The reverse spray channel outlet 3521 is located at the edge of the spray plate 3. Figure 6 The clockwise direction indicates the rotation direction of the back side of the spray plate 3 when the motor rotor is reversed. Each reverse spray channel 352 is in an arc shape. Specifically, for the same reverse spray channel 352, its reverse spray channel outlet 3521 is set counterclockwise relative to the phase of the reverse spray channel inlet 3522. In this way, when the motor rotor is reversed, the direction in which the cooling oil is sprayed from the reverse spray channel 352 is opposite to the rotation direction, thereby offsetting the speed at which the cooling oil sprayed out reaches the stator winding under high-speed rotation, and reducing the impact of the spray cooling oil on the stator winding at high speed.

[0046] When the motor is in the reverse state, since the reverse speed of the motor is usually lower than the forward speed, no internal heat dissipation channel of the rotor is set during the reverse rotation, and only the rotational spraying of the stator winding by the rotor end is realized. Specifically, the cooling oil is injected into the reverse oil filling chamber 12 through the reverse oil filling pipe 42, and then enters the reverse center channel 5D through the reverse oil filling hole 16. Then, the cooling oil moves along the reverse center channel 5D to the two ends of the rotor to the spray plate 3, passes through the through channel 34 on the spray plate 3, enters the spray plate reverse distribution channel 351 on the reverse side of the spray plate 3, and finally passes through the reverse spray channel 352 to be sprayed onto the stator winding.

[0047] The above-mentioned forward oil passage and reverse oil passage, finally, because the spraying directions of the forward spray oil passage 33 and the reverse spray oil passage 352 are opposite to the directions of the rotor in forward and reverse rotation, respectively, the impact of the cooling oil sprayed on the stator winding on the stator winding is reduced regardless of the forward rotation or reverse rotation. At the same time, the forward oil passage flows through the inside of the rotor and the area near the permanent magnet, which comprehensively dissipates the heat of the rotor under the forward high-speed rotation, reduces the risk of permanent magnet demagnetization, and increases the service life of the rotor. At the same time, the switching of the two-way valve 43 during forward and reverse rotation ensures that the two forward oil passages are oiled during forward rotation, and the reverse oil passages are oiled during reverse rotation. In addition, in order to ensure that the silicon steel sheet group 5 and the spray plate 3 rotate stably with the hollow shaft assembly 1, a first keyway 515 is provided on the central through holes of the non-central thin silicon steel sheet 51 and the central thin silicon steel sheet 52, and a second keyway 36 is also provided on the central through hole of the spray plate 3. The spray plate 3 and the non-central thin silicon steel sheet 51 and the central thin silicon steel sheet 52 are key-connected to the hollow shaft assembly 1.

[0048] According to the above-mentioned forward oil passage and reverse oil passage, since the rotor is usually in high-speed rotation, the setting of the forward oil passage and the reverse oil passage will inevitably hinder the rotation of the rotor. In addition, whether the cooling oil injected into the forward oil passage and the reverse oil passage can flow evenly around the rotor and evenly and efficiently dissipate heat for rotors of different sizes and specifications plays a key role in the normal operation of the embedded rotor. Therefore, how to design a flow passage with a reasonable structure according to the size and speed requirements of the rotor becomes the key to the setting of the above-mentioned forward oil passage and the reverse oil passage. To this end, the present invention also provides a corresponding optimization design method.

[0049] The present invention provides a method for optimizing the rotor structure of a high-speed embedded permanent magnet synchronous motor, comprising:

[0050] 1. Take the number and relative position of permanent magnets on the embedded rotor as the first optimization target to perform thermal-fluid coupling optimization to determine the number and position size of the forward and reverse oil channels;

[0051] 2. Perform thermomechanical coupling optimization with the second optimization goal of maximizing cooling transfer and minimizing flow resistance to determine the structural dimensions of the forward and reverse oil channels and the cooling oil supply rate at different speeds;

[0052] In the above step 1, the number of forward oil channels and reverse oil channels is determined according to the number and relative positions of permanent magnets. The relative positions of the rotor internal flow channels, permanent magnet cooling flow channels, and forward spray flow channels are optimized through thermal-fluid coupling optimization design. At the same time, the relative positions of the permanent magnet cooling flow channels, forward spray flow channels, and permanent magnets are determined through thermal-fluid coupling optimization design according to the number and relative positions of permanent magnets.

[0053] The structural dimensions of the forward oil channel and the reverse oil channel in the above step 2 are specifically performed according to the second optimization goal of maximizing the cold transfer and minimizing the flow resistance, and the thermomechanical coupling optimization is performed to determine the cross-sectional area of ​​the forward center flow channel 5A, the depth and width of the spray plate distribution flow channel 31, the aperture of the rotor internal flow channel 5B, the aperture of the permanent magnet cooling flow channel 5C, the angle and cross-sectional area of ​​the forward spray flow channel 33, the cross-sectional area of ​​the reverse center flow channel 5D, the cross-sectional area of ​​the crossing flow channel 34, the depth and width of the spray plate reverse distribution flow channel 351, and the angle and cross-sectional area of ​​the reverse spray flow channel 352.

[0054] The cooling oil supply rate at different speeds in the above step 2 is specifically to perform thermal coupling optimization with the second optimization goal of maximizing the cooling transfer and minimizing the flow resistance, and determine the cooling oil supply rate at different speeds of the motor forward and reverse rotation. Because the cooling oil supply rate affects the heat transfer efficiency of the cooling oil and the resistance to the motor rotation, the motor cooling requirements are different at different speeds.

[0055] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0056] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0057] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0059] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A high-speed embedded permanent magnet synchronous motor rotor structure, characterized in that: It includes a hollow shaft assembly, an end plate, a spray plate, an oil injection assembly, a silicon steel sheet group, and a bearing; the inside of the hollow shaft assembly is divided into three parts by a three-stage stepped hole form, wherein the part with the largest aperture is the forward oil injection chamber, the part with the second largest aperture is the reverse oil injection chamber, and the part with the smallest aperture is the hollow chamber; a first partition plate is fixedly installed on the stepped shoulders of the forward oil injection chamber and the reverse oil injection chamber, and a first through hole is opened at the center of the first partition plate; a second partition plate is fixedly installed on the stepped shoulders between the reverse oil injection chamber and the hollow chamber; two centrally symmetrical forward oil injection holes are opened on the cavity wall of the forward oil injection chamber along the radial direction of the hollow shaft; two centrally symmetrical reverse oil injection holes are also opened on the cavity wall of the reverse oil injection chamber along the radial direction of the hollow shaft, and when observed from the cross section of the hollow shaft assembly, the two forward oil injection holes and the two reverse oil injection holes are 90° out of phase with each other; The oil injection assembly comprises a forward oil injection pipe, a reverse oil injection pipe and a two-way valve. The forward oil injection pipe and the reverse oil injection pipe extend into the hollow shaft assembly along the axis of the hollow shaft. The diameter of the forward oil injection pipe is larger than that of the reverse oil injection pipe. The forward oil injection pipe is sleeved on the outside of the reverse oil injection pipe. The forward oil injection pipe extends into the forward oil injection chamber and is stopped. The reverse oil injection pipe passes through the forward oil injection chamber, passes through the first through hole on the first partition plate and then extends into the reverse oil injection chamber. The silicon steel sheet group is sleeved on the outside of the hollow shaft assembly through interference fit to form the main structure of the rotor. The silicon steel sheet group is stacked by a number of odd or even thin silicon steel sheets. A slot for inserting a permanent magnet is opened near the edge of the circular sheet of the silicon steel sheet group. A spray plate and an end plate are sequentially arranged at the ends of both sides of the silicon steel sheet group from the inside to the outside. Forward flow channels and reverse flow channels are formed in the silicon steel sheet group, the hollow shaft assembly, the end plate, and the spray plate. The forward-rotation flow channel includes a forward-rotation central flow channel, a spray plate distribution flow channel, a rotor internal flow channel, a permanent magnet cooling flow channel, and a forward-rotation spray flow channel; In the silicon steel sheet group, except for the central 1-2 thin silicon steel sheets, the center of which has a central hole for interference fit installation of the hollow shaft assembly, a positive rotation center flow channel groove is opened on the central hole relative to the two positive rotation oil injection holes of the hollow shaft assembly; the central 1-2 thin silicon steel sheets in the silicon steel sheet group also have a positive rotation center flow channel groove opened on the central hole relative to the two positive rotation oil injection holes of the hollow shaft assembly; the positive rotation center flow channel groove on each thin silicon steel sheet in the silicon steel sheet group constitutes two positive rotation center flow channels running through the silicon steel sheet group, and the positive rotation center flow channels are connected to the positive rotation oil injection cavity through the positive rotation oil injection hole; The center of the spray plate has a central through hole for interference fit on the outside of the hollow shaft assembly. The central through hole is surrounded by a circle of annular grooves to form a spray plate distribution channel. An annular boss is provided between the spray plate distribution channel and the central through hole. The thickness of the annular boss is equal to half the height of the forward rotating central flow channel groove.

2. A high-speed embedded permanent magnet synchronous motor rotor structure as claimed in claim 1, characterized in that: The internal flow channel of the rotor is formed by interconnecting the internal flow channel holes set on each thin silicon steel sheet. The internal flow channel holes on the thin silicon steel sheet are symmetrically arranged. The number of the internal flow channel holes is consistent with the number of permanent magnets on the circumference of the rotor. The center distance of the internal flow channel holes on each thin silicon steel sheet from the center is different. The internal flow channel holes on the thin silicon steel sheets at both ends of the rotor are closest to the center and their aperture range is completely covered within the range of the spray plate distribution flow channel; from both ends to the middle, the internal flow channel holes on the thin silicon steel sheets gradually move away from the center in the radial direction of the same phase, but the internal flow channel holes on adjacent thin silicon steel sheets are still partially connected, forming a number of rotor internal flow channels that are obliquely outward from the two ends to the middle; at the same cross-sectional position, two rotor internal flow channels are interconnected in the center of the rotor; Each thin silicon steel sheet is provided with a permanent magnet cooling channel hole at a radial position close to the permanent magnet, and the permanent magnet cooling channel holes of two adjacent thin silicon steel sheets are interconnected to form a permanent magnet cooling channel; the number and phase of the permanent magnet cooling channels are the same as the number and phase of the channels inside the rotor; the permanent magnet cooling channels and the channels inside the rotor of the same phase are connected at the thin silicon steel sheet in the center of the rotor; The permanent magnet cooling channel extends along the rotor axis to the spray plates at both ends and is connected with the forward-rotating spray channel on the front of the spray plate; the forward-rotating spray channel is a groove arranged on the front of the spray plate, and the number and phase position of the forward-rotating spray channel correspond to the number and phase of the permanent magnet cooling channel one by one; each forward-rotating spray channel is arranged at the edge position of the front of the spray plate, and the forward-rotating spray channel has a forward-rotating spray channel inlet and a forward-rotating spray channel outlet; the forward-rotating spray channel inlet is connected with the permanent magnet cooling channel, and the forward-rotating spray channel outlet is located at the edge of the front of the spray plate; the direction of the rotor's forward rotation is clockwise, and the direction of the forward-rotating spray channel is counterclockwise.

3. A high-speed embedded permanent magnet synchronous motor rotor structure as claimed in claim 2, characterized in that: The reversing flow channel includes a reversing central flow channel, a crossing flow channel, a spray plate reversing distribution flow channel, and a reversing spray flow channel; a reversing central flow channel groove is provided on the central through hole of each thin silicon steel sheet in the silicon steel sheet group at a phase position relative to the reversing oil injection hole on the hollow shaft assembly, and the reversing central flow channel groove on each thin silicon steel sheet in the silicon steel sheet group constitutes two upper and lower reversing central flow channels extending axially along the hollow shaft assembly, and the reversing central flow channel is connected to the reversing oil injection cavity through the reversing oil injection hole; the crossing flow channel is provided on the central through hole of the spray plate, and the crossing flow channel is a groove axially extending on the central through hole of the spray plate, and the number and position of the crossing flow channels correspond to the number and position of the reversing central flow channels, and the height of the crossing flow channel is less than the height of the annular boss on the spray plate, and the height of the crossing flow channel is the same as the height of the reversing central flow channel; A spray plate reverse distribution channel formed by an annular groove is arranged at the through hole near the center on the reverse side of the spray plate, and a plurality of reverse spray channels are radially distributed on the reverse side of the spray plate; the reverse spray channel has a reverse spray channel inlet and a reverse spray channel outlet, the reverse spray channel inlet is connected to the spray plate reverse distribution channel, and the reverse spray channel outlet is located at the edge of the spray plate; The clockwise direction represents the rotation direction of the back side of the spray plate when the motor rotor reverses. Each reverse spray flow channel is in an arc shape. For the same reverse spray flow channel, the phase of the reverse spray flow channel outlet is set counterclockwise relative to the phase of the reverse spray flow channel inlet.

4. An optimization design method for a high-speed embedded permanent magnet synchronous motor rotor structure according to any one of claims 1 to 3, characterized in that: S1: Taking the number and relative position of permanent magnets on the embedded rotor as the first optimization target, thermal-fluid coupling optimization is performed to determine the number and position size of the forward oil passage and the reverse oil passage; S2: Perform thermomechanical coupling optimization with the second optimization goal of maximizing cooling transfer and minimizing flow resistance to determine the structural dimensions of the forward and reverse oil channels and the cooling oil supply rate at different speeds.

5. The method for optimizing the rotor structure of a high-speed embedded permanent magnet synchronous motor according to claim 4, characterized in that: The number of forward oil channels and reverse oil channels in S1 is determined according to the number and relative positions of permanent magnets. The relative positions of the rotor internal flow channels, permanent magnet cooling flow channels, and forward spray flow channels are optimized through thermal-fluid coupling optimization design. At the same time, the relative positions of the permanent magnet cooling flow channels, forward spray flow channels, and permanent magnets are determined through thermal-fluid coupling optimization design according to the number and relative positions of permanent magnets.

6. The method for optimizing the rotor structure of a high-speed embedded permanent magnet synchronous motor according to claim 5, characterized in that: The structural dimensions of the forward oil channel and the reverse oil channel in S2 are specifically thermomechanical coupling optimized based on the second optimization objective of maximizing the cold transfer and minimizing the flow resistance, and the cross-sectional area of ​​the forward center flow channel, the depth and width of the spray plate distribution flow channel, the aperture of the rotor internal flow channel, the aperture of the permanent magnet cooling flow channel, the angle and cross-sectional area of ​​the forward spray flow channel, the cross-sectional area of ​​the reverse center flow channel, the cross-sectional area of ​​the crossing flow channel, the depth and width of the spray plate reverse distribution flow channel, and the angle and cross-sectional area of ​​the reverse spray flow channel are determined; the cooling oil supply rate at different speeds in S2 is specifically thermomechanical coupling optimized based on the second optimization objective of maximizing the cold transfer and minimizing the flow resistance, and the cooling oil supply rate at different forward and reverse speeds of the motor is determined.

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