阅读说明：本技术 一种电机热套的高均匀性加热装置 (High-uniformity heating device for motor hot jacket ) 是由 谭若兮 叶尚斌 王涛 喻成 于 2021-07-30 设计创作，主要内容包括：本发明公开了一种电机热套的高均匀性加热装置,包括能够与电机热套的内腔相适配的感应线圈和与感应线圈连接的交流电源模块,感应线圈为n匝空心螺旋铜线圈；感应线圈的整体形状呈锥台型,n匝空心螺旋铜线圈沿纵向等间距绕制,n匝空心螺旋铜线圈的绕制半径从上至下线性递增。本发明能实现电机热套的高均匀性加热,适用于瞬态加热温度高且均匀性要求严苛的场合。(The invention discloses a high-uniformity heating device of a motor thermal sleeve, which comprises an induction coil and an alternating current power supply module, wherein the induction coil can be matched with an inner cavity of the motor thermal sleeve; the whole shape of the induction coil is frustum-shaped, the n turns of the hollow spiral copper coil are wound at equal intervals along the longitudinal direction, and the winding radius of the n turns of the hollow spiral copper coil is increased in a linear mode from top to bottom. The invention can realize the high-uniformity heating of the motor hot jacket and is suitable for occasions with high transient heating temperature and strict uniformity requirements.)

1. A high-uniformity heating device of a motor thermal sleeve comprises an induction coil (1) which can be matched with an inner cavity of a motor thermal sleeve (2) and an alternating current power supply module connected with the induction coil (1), wherein the induction coil (1) is an n-turn hollow spiral copper coil; the method is characterized in that: the whole shape of the induction coil (1) is frustum-shaped, n turns of hollow spiral copper coils are wound at equal intervals along the longitudinal direction, and the winding radius of the n turns of hollow spiral copper coils is increased in a linear mode from top to bottom.

2. The high uniformity heating apparatus of the motor thermal jacket according to claim 1, characterized in that: and an insulating layer (3) for separating the induction coil (1) from the motor thermal sleeve (2) is further arranged on the periphery of the induction coil (1).

3. The high uniformity heating apparatus of the motor thermal jacket according to claim 1 or 2, characterized in that: when the motor thermal sleeve (2) needs to be heated, the induction coil (1) and the insulating layer (3) longitudinally extend into the inner cavity of the motor thermal sleeve (2) from top to bottom, and the highest position of the induction coil (1) is flush with the top end of the motor thermal sleeve (2).

4. The high uniformity heating apparatus of the motor thermal jacket according to any one of claims 1 to 3, wherein: the number n of turns of the hollow spiral copper coil of the induction coil (1) and the winding radius R of the first turn of the hollow spiral copper coil of the induction coil (1)_C1The nth turn of hollow spiral copper of the induction coil (1)Winding radius R of coil_CnHeight H of the induction coil (1)_CnAnd the longitudinal distance l between two adjacent turns of the hollow spiral copper coil_CObtained by the following method:

firstly, establishing a motor hot jacket model and an induction coil model based on finite element simulation software;

secondly, setting a structural parameter R 'according to constraint conditions 1a to 1 c'_C1、R′_Cn、H′_Cn、l′_CNumerical range and variation step length and structural parameter R'_s、H′_sThe numerical value of d'; wherein, the constraint condition 1a is: 0 < R'_C1＜R′_Cn＜R′_sThe constraint 1b is: 0 < H'_Cn＜H′_sThe constraint 1c is:and isIs a positive integer, R'_C1Represents a winding radius, R ', of a first-turn hollow-spiral copper coil of the induction coil model'_CnDenotes a winding radius, H ', of an n ' th turn hollow-spiral copper coil of the induction coil model '_CnDenotes a height of the induction coil model, and n ' denotes a number of turns, l ' of the hollow spiral copper coil of the induction coil model '_CRepresenting the longitudinal spacing, R ', of two adjacent turns of the hollow helical copper coil of the induction coil model'_sRepresents the inner radius, H ', of the motor thermal jacket model'_sDenotes a cavity height of the motor heat jacket model, d ' denotes an outer diameter, R ' of the hollow spiral copper coil in the induction coil model '_sEqual to the inner radius R of the motor thermal sleeve (2)_s，H′_sEqual to the height H of the inner cavity of the motor thermal sleeve (2)_sD' is equal to the outer diameter d of the hollow spiral copper coil in the induction coil (1);

thirdly, setting the induction coil model as copper, the motor thermal sleeve model as aluminum, the thermal conductivity coefficient, specific heat capacity, density and electric conductivity of the aluminum along with the temperature change, and setting an initial reference temperature;

fourthly, editing the thermal property of the motor thermal sleeve model, and selectively establishing connection related to temperature feedback; then, mesh subdivision is carried out on the motor thermal jacket model and the induction coil model, electromagnetic field time domain simulation is selected, simulation duration is set, and electromagnetic field intensity distribution of the surface of the motor thermal jacket model is calculated by adopting a finite element algorithm to obtain electromagnetic field intensity distribution data of the surface of the motor thermal jacket model;

fifthly, establishing a connection relation between an electromagnetic field simulation module and a temperature field simulation module, setting initial temperature and heating time, importing electromagnetic field intensity distribution data of the surface of the motor hot jacket model into simulation software of the temperature field, setting the surface of the motor hot jacket model capable of carrying out heat transfer and heat radiation, then carrying out electromagnetic-thermal coupling simulation analysis calculation, and updating the heating time until constraint conditions are met for 1d, so as to obtain various induction coil structure schemes; wherein, an induction coil structure scheme corresponds to a group of structure parameters R'_C1、R′_Cn、H′_Cn、l′_CAnd an axial highest temperature T of the surface of the motor hot jacket model_vmaxAxial minimum temperature T_vminRadial maximum temperature T_hmaxRadial minimum temperature T_hmin(ii) a Constraint 1d is: t is_vminNot less than a preset first temperature threshold, and T_hminThe temperature is more than or equal to a preset first temperature threshold;

sixthly, screening m induction coil structure schemes meeting constraint conditions 1e from the multiple induction coil structure schemes; wherein, the constraint condition 1e is: delta T_vNot more than a preset second temperature threshold value, and delta T_hNot more than a predetermined second temperature threshold, Δ T_vIndicating the maximum axial temperature difference, Δ T_v＝T_vmax-T_vmin，ΔT_hDenotes the radial maximum temperature difference, Δ T_h＝T_hmax-T_hmin；

Seventhly, selecting a group of structural parameters R 'corresponding to any one of the m induction coil structural schemes'_C1、R′_Cn、H′_Cn、l′_C(ii) a And reacting said R_C1Is equal toR 'in group structure parameters'_C1Allowing said R to stand_CnEqual to R 'in the set of structural parameters'_CnAllowing said H to stand_CnIs equal to H 'in the set of structural parameters'_CnLet l be_CIs equal to l 'in the set of structural parameters'_C(ii) a H is to be_Cn、l_CAnd d is substituted into the formula:and calculating to obtain the n.

5. The high uniformity heating apparatus of the motor thermal jacket according to claim 4, characterized in that: after m induction coil structure schemes are obtained through the sixth step, processing of steps S1 to S2 is carried out, and a heating device with the best uniformity is obtained; wherein the content of the first and second substances,

step S1 is: setting the corresponding delta T of each induction coil structure scheme in the m induction coil structure schemes_v、ΔT_hThe larger value of the two is taken as the maximum temperature difference delta T corresponding to the induction coil structure scheme_mM maximum temperature differences Delta T are obtained_m；

Step S2 is: m maximum temperature differences Delta T are selected_mIs the set of structural parameters R 'corresponding to the minimum value in'_C1、R′_Cn、H′_Cn、l′_C(ii) a And reacting said R_C1Equal to R 'in the set of structural parameters'_C1Allowing said R to stand_CnEqual to R 'in the set of structural parameters'_CnAllowing said H to stand_CnIs equal to H 'in the set of structural parameters'_CnLet l be_CIs equal to l 'in the set of structural parameters'_C(ii) a H is to be_Cn、l_CAnd d is substituted into the formula:and calculating to obtain the n.

Technical Field

The invention belongs to the technical field of electromagnetic induction heating, and particularly relates to a high-uniformity heating device for a motor hot jacket.

Background

Because the aluminum alloy has low density, light weight and high heat conductivity coefficient, the aluminum material is usually adopted as the material of the motor thermal sleeve (motor shell) in the market. In the process of heating the motor hot jacket by electromagnetic induction, because the alternating current is introduced to be large, large current flows through the hollow spiral copper coil, a large magnetic field is generated around the coil, and the motor hot jacket in the magnetic field range is quickly heated under the eddy current effect. According to the principle of expansion with heat and contraction with cold, the electromagnetic induction heating mode is commonly adopted in the industry to heat the motor heat jacket, so that the process assembly is completed after the periphery of the motor heat jacket is heated and expands in an equivalent manner.

The electromagnetic induction heating belongs to a transient process, and the temperature of the heated equipment is in a process of gradually increasing and accumulating along with the increase of the heating time. The heating device of the existing motor hot jacket comprises an induction coil which can be matched with an inner cavity of the motor hot jacket and an alternating current power supply module which is connected with the induction coil, wherein the induction coil is a multi-turn hollow spiral copper coil which is equal in upper and lower width and is uniformly distributed at equal longitudinal intervals. The heating device has a good heating effect on the motor hot jacket with a small size, but when the size of the motor hot jacket is large, the heating device is influenced by electromagnetic induction skin effect and edge effect, so that the generated eddy current is unevenly distributed, and the uniform heating of the motor hot jacket is difficult to realize. If the temperature rise rate difference of the surfaces of the motor hot jacket is too large, the phenomenon of local over-temperature occurs, so that the deformation of the periphery of the motor hot jacket is inconsistent, and finally the smooth assembly of the motor stator and the motor hot jacket cannot be completed. Particularly for the motor hot jacket with the T-shaped process grooves with uneven thickness on the surface, the T-shaped process grooves are used as the weak parts for magnetic field cutting, and the problem of over-temperature ablation is easily caused at the grooves, so that the motor shell is damaged and the heating process fails.

Disclosure of Invention

The invention aims to provide a high-uniformity heating device for a motor hot jacket, which is used for realizing high-uniformity heating of the motor hot jacket and is suitable for occasions with high transient heating temperature and strict uniformity requirements.

The high-uniformity heating device of the motor thermal jacket comprises an induction coil which can be matched with an inner cavity of the motor thermal jacket and an alternating current power supply module connected with the induction coil, wherein the induction coil is an n-turn hollow spiral copper coil; the whole shape of the induction coil is frustum-shaped, the n turns of the hollow spiral copper coil are wound at equal intervals along the longitudinal direction, and the winding radius of the n turns of the hollow spiral copper coil is increased in a linear mode from top to bottom.

Preferably, the periphery of the induction coil is further provided with an insulating layer for separating the induction coil from the motor thermal sleeve. The insulating layer can prevent the potential safety hazard of electric leakage or short circuit caused by direct contact between the induction coil and the motor hot jacket.

Preferably, when the motor thermal sleeve needs to be heated, the induction coil and the insulating layer longitudinally extend into the inner cavity of the motor thermal sleeve from top to bottom, and the highest position of the induction coil is flush with the top end of the motor thermal sleeve.

Preferably, the number n of turns of the hollow spiral copper coil of the induction coil and the winding radius R of the first turn of the hollow spiral copper coil of the induction coil_C1Winding radius R of nth turn hollow spiral copper coil of induction coil_CnHeight H of induction coil_CnAnd the longitudinal distance l between two adjacent turns of the hollow spiral copper coil_CObtained by the following method:

firstly, establishing a motor thermal sleeve model and an induction coil model based on finite element simulation software.

Secondly, setting a structural parameter R 'according to constraint conditions 1a to 1 c'_C1、R′_Cn、H′_Cn、l′_CNumerical range and variation step length and structural parameter R'_s、H′_sThe numerical value of d'; wherein, the constraint condition 1a is: 0 < R'_C1＜R′_Cn＜R′_sThe constraint 1b is: 0 < H'_Cn＜H′_sThe constraint 1c is:and isn 'is a positive integer, R'_C1Represents a winding radius, R ', of a first-turn hollow-spiral copper coil of the induction coil model'_CnDenotes a winding radius, H ', of an n ' th turn hollow-spiral copper coil of the induction coil model '_CnDenotes a height of the induction coil model, and n ' denotes a number of turns, l ' of the hollow spiral copper coil of the induction coil model '_CRepresenting the longitudinal spacing, R ', of two adjacent turns of the hollow helical copper coil of the induction coil model'_sRepresents the inner radius, H ', of the motor thermal jacket model'_sDenotes a cavity height of the motor heat jacket model, d ' denotes an outer diameter, R ' of the hollow spiral copper coil in the induction coil model '_sEqual to the inner radius R of the motor thermal sleeve_s，H′_sEqual to the height H of the inner cavity of the motor thermal sleeve_sAnd d' is equal to the outer diameter d of the hollow spiral copper coil in the induction coil.

And thirdly, setting the induction coil model as copper, the motor thermal sleeve model as aluminum, setting the thermal conductivity coefficient, specific heat capacity, density and electric conductivity of the aluminum along with the temperature change, and setting an initial reference temperature.

Fourthly, editing the thermal property of the motor thermal sleeve model, and selectively establishing connection related to temperature feedback; then, mesh generation is carried out on the motor thermal jacket model and the induction coil model, electromagnetic field time domain simulation is selected, simulation duration is set, and electromagnetic field intensity distribution on the surface of the motor thermal jacket model is calculated by adopting a finite element algorithm to obtain electromagnetic field intensity distribution data on the surface of the motor thermal jacket model.

Fifthly, establishing a connection relation between an electromagnetic field simulation module and a temperature field simulation module, setting initial temperature and heating time, importing electromagnetic field intensity distribution data of the surface of the motor hot jacket model into simulation software of the temperature field, setting the surface of the motor hot jacket model capable of carrying out heat transfer and heat radiation, then carrying out electromagnetic-thermal coupling simulation analysis calculation, and updating the heating time until constraint conditions are met for 1d, so as to obtain various induction coil structure schemes; wherein, an induction coil structure scheme corresponds to a group of structure parameters R'_C1、R′_Cn、H′_Cn、l′_CAnd an axial highest temperature T of the surface of the motor hot jacket model_vmaxAxial minimum temperature T_vminRadial maximum temperature T_hmaxRadial minimum temperature T_hmin(ii) a Constraint 1d is: t is_vminNot less than a preset first temperature threshold, and T_hminThe temperature is more than or equal to a preset first temperature threshold value.

Sixth aspect of the inventionStep, screening m induction coil structure schemes meeting constraint conditions 1e from the multiple induction coil structure schemes; wherein, the constraint condition 1e is: delta T_vNot more than a preset second temperature threshold value, and delta T_hNot more than a predetermined second temperature threshold, Δ T_vIndicating the maximum axial temperature difference, Δ T_v＝T_vmax-T_vmin，ΔT_hDenotes the radial maximum temperature difference, Δ T_h＝T_hmax-T_hmin。

Seventhly, selecting a group of structural parameters R 'corresponding to any one of the m induction coil structural schemes'_C1、R′_Cn、H′_Cn、l′_C(ii) a And reacting said R_C1Equal to R 'in the set of structural parameters'_C1Allowing said R to stand_CnEqual to R 'in the set of structural parameters'_CnAllowing said H to stand_CnIs equal to H 'in the set of structural parameters'_CnLet l be_CIs equal to l 'in the set of structural parameters'_C(ii) a H is to be_Cn、l_CAnd d is substituted into the formula:and calculating to obtain the n. The m induction coil structure schemes all meet the requirement of high-uniformity heating, so that any one induction coil structure scheme can be selected.

Preferably, after m induction coil structure schemes are obtained through the sixth step, the processing of steps S1 to S2 is performed, so that a heating device with the best uniformity can be obtained; wherein the content of the first and second substances,

step S1 is: setting the corresponding delta T of each induction coil structure scheme in the m induction coil structure schemes_v、ΔT_hThe larger value of the two is taken as the maximum temperature difference delta T corresponding to the induction coil structure scheme_m(i.e. Δ T)_m＝max(ΔT_v，ΔT_h) M maximum temperature differences DeltaT) are obtained_m。

Step S2 is: m maximum temperature differences Delta T are selected_mIs the set of structural parameters R 'corresponding to the minimum value in'_C1、R′_Cn、H′_Cn、l′_C(ii) a And reacting said R_C1Equal to R 'in the set of structural parameters'_C1Allowing said R to stand_CnEqual to R 'in the set of structural parameters'_CnAllowing said H to stand_CnIs equal to H 'in the set of structural parameters'_CnLet l be_CIs equal to l 'in the set of structural parameters'_C(ii) a H is to be_Cn、l_CAnd d is substituted into the formula:and calculating to obtain the n. The heating device comprising the induction coil has the best heating uniformity.

The invention adopts the induction coil with the integral shape of the frustum to heat the motor hot jacket, and the induction coil is gradually widened from top to bottom, so that the effective magnetic line density of the cutting motor hot jacket at different axial positions of the motor hot jacket is different, the eddy current distribution on the surface of the motor hot jacket is changed, namely, the surface temperature distribution of the motor hot jacket is directly optimized, the axial and radial temperature difference is reduced, the electromagnetic heating uniformity is effectively improved, the synchronous rise of the surface temperature of the motor hot jacket is ensured, the distribution is uniform, the applicability to the motor hot jacket with different sizes is strong, and the invention is particularly suitable for occasions with high transient heating temperature and strict uniformity requirement; the problem of over-temperature ablation of certain positions caused by poor heating temperature uniformity of the existing motor hot jacket is effectively solved, and the service life of the motor hot jacket can be prolonged.

Drawings

Fig. 1 is a schematic structural diagram of the induction coil and the insulating layer placed in the thermal sleeve of the motor in the embodiment.

Fig. 2 is a schematic structural diagram of the induction coil in this embodiment.

Fig. 3 is a front view of the induction coil in the present embodiment.

Fig. 4 is a bottom view of the induction coil in the present embodiment.

Detailed Description

As shown in fig. 1 to 4, the high uniformity heating apparatus for a motor thermal jacket in the present embodiment includes an induction coil 1 capable of adapting to an inner cavity of a motor thermal jacket 2, an insulating layer 3 disposed on a periphery of the induction coil 1 and separating the induction coil 1 from the motor thermal jacket 2, and an ac power supply module (not shown in the figure) connected to the induction coil 1. The induction coil 1 is an n-turn hollow spiral copper coil, and a hollow pipeline of the hollow spiral copper coil is a water channel and is used for cooling the induction coil during heating. The whole shape of the induction coil 1 is frustum-shaped, n turns of hollow spiral copper coils are wound at equal intervals along the longitudinal direction, and the winding radius of the n turns of hollow spiral copper coils is increased in a linear mode from top to bottom. The motor thermal sleeve 2 is of a hollow cylinder structure made of aluminum materials, the top end of the motor thermal sleeve 2 is hollow, the bottom of the motor thermal sleeve is provided with an opening, and a T-shaped process groove 21 (matched with a motor stator and mainly used for controlling the angle of process equipment) is dug on the inner edge of the top end of the motor thermal sleeve 2. When the motor thermal sleeve 2 needs to be heated, the induction coil 1 and the insulating layer 3 longitudinally extend into the inner cavity of the motor thermal sleeve 2 from top to bottom, and the highest position of the induction coil 1 is flush with the top end of the motor thermal sleeve 2; then alternating current (the frequency is 8.5kHz, the current is 1100 amperes) is introduced into the induction coil 1 through the alternating current power supply module to generate a changing magnetic field, the motor thermal sleeve is positioned in the magnetic field, magnetic lines of force cut the motor thermal sleeve, so that eddy current is generated in the motor thermal sleeve, the eddy current enables current carriers in the motor thermal sleeve to move irregularly at a high speed, the current carriers collide with atoms and rub to generate heat energy, and the heat energy reaches the surface of the motor thermal sleeve in a heat conduction mode. Because the generated magnetic field is uniformly distributed, the surface temperature rise rate of the motor thermal jacket is basically consistent, and the method is very effective in occasions with higher requirement on the temperature uniformity of the motor thermal jacket.

In this embodiment, the outer diameter d of the hollow spiral copper coil is equal to 10mm, the inner diameter is 8mm, and the inner radius R of the motor thermal sleeve 2 in this embodiment is_sEqual to 120mm, the height H of the inner cavity of the motor thermal sleeve 2_sEqual to 222 mm.

The structural parameters of the induction coil 1 in this embodiment are, i.e. the number of turns n of the hollow spiral copper coil of the induction coil 1, and the winding radius R of the first-turn hollow spiral copper coil of the induction coil 1_C1Winding radius R of nth turn hollow spiral copper coil of induction coil 1_CnHeight H of induction coil 1_CnAnd the longitudinal direction of two adjacent turns of the hollow spiral copper coilTo the spacing l_CObtained by the following method:

firstly, establishing a motor thermal sleeve model and an induction coil model based on finite element simulation software.

Secondly, setting a structural parameter R 'according to constraint conditions 1a to 1 c'_C1、R′_Cn、H′_Cn、l′_CNumerical range and variation step length and structural parameter R'_s、H′_sThe numerical value of d'; wherein, the constraint condition 1a is: 0 < R'_C1＜R′_Cn＜R′_sThe constraint 1b is: 0 < H'_Cn＜H′_sThe constraint 1c is:and isn 'is a positive integer, R'_C1Represents a winding radius, R ', of a first-turn hollow-spiral copper coil of the induction coil model'_CnDenotes a winding radius, H ', of an n ' th turn hollow-spiral copper coil of the induction coil model '_CnDenotes a height of the induction coil model, and n ' denotes a number of turns, l ' of the hollow spiral copper coil of the induction coil model '_CRepresenting the longitudinal spacing, R ', of two adjacent turns of the hollow helical copper coil of the induction coil model'_sRepresents the inner radius, H ', of the motor thermal jacket model'_sDenotes a cavity height of the motor heat jacket model, d ' denotes an outer diameter, R ' of the hollow spiral copper coil in the induction coil model '_s＝120mm，H′_s＝222mm，d′＝10mm。

And thirdly, setting the material of the induction coil model as copper, the material of the motor thermal sleeve model as aluminum, setting the thermal conductivity, the specific heat capacity, the density and the electric conductivity of the aluminum along with the temperature change (namely setting a plurality of thermal conductivity values, a plurality of specific heat capacity values, a plurality of density values and a plurality of electric conductivity values of the aluminum relative to the temperature), and setting an initial reference temperature. The relationship between the thermal conductivity value, the specific heat capacity value, the density value and the electrical conductivity value and the temperature can be obtained by checking a data manual of the motor thermal sleeve.

Fourthly, editing the thermal property of the motor thermal sleeve model, and selectively establishing connection related to temperature feedback; then, mesh generation is carried out on the motor thermal jacket model and the induction coil model, electromagnetic field time domain simulation is selected, simulation duration is set, and electromagnetic field intensity distribution on the surface of the motor thermal jacket model is calculated by adopting a finite element algorithm to obtain electromagnetic field intensity distribution data on the surface of the motor thermal jacket model.

Fifthly, establishing a connection relation between the electromagnetic field simulation module and the temperature field simulation module (namely, guiding the motor thermal sleeve model after electromagnetic field simulation calculation into temperature field simulation software), setting initial temperature and heating time, guiding electromagnetic field intensity distribution data on the surface of the motor thermal sleeve model into the temperature field simulation software, setting the surface of the motor thermal sleeve model capable of carrying out heat transfer and heat radiation, then carrying out electromagnetic-thermal coupling simulation analysis calculation, and updating the heating time to obtain various induction coil structure schemes meeting constraint conditions 1 d; wherein, an induction coil structure scheme corresponds to a group of structure parameters R'_C1、R′_Cn、H′_Cn、l′_CAnd an axial highest temperature T of the surface of the motor hot jacket model_vmaxOne axial lowest temperature T of the surface of the motor hot jacket model_vminA radial highest temperature T of the surface of the motor hot jacket model_hmaxA radial minimum temperature T of the surface of the motor thermal sleeve model_hmin(ii) a Constraint 1d is: t is_vmin160 ℃ or more (i.e. the preset first temperature threshold is equal to 160 ℃ in the embodiment), and T is_hmin≥160℃。

Sixthly, screening out the multiple induction coil structure schemes meeting the constraint condition 1 from the fifth step_eThe m induction coil structure schemes of (1); wherein, the constraint condition 1e is: delta T_vNot more than 10 deg.C (i.e. the preset second temperature threshold is equal to 10 deg.C), and Δ T_h≤10℃，ΔT_vIndicating the maximum axial temperature difference, Δ T_v＝T_vmax-T_vmin，ΔT_hDenotes the radial maximum temperature difference, Δ T_h＝T_hmax-T_hmin。

Seventh step, theDelta T corresponding to each induction coil structure scheme in m induction coil structure schemes_v、ΔT_hThe larger value of the two is taken as the maximum temperature difference delta T corresponding to the induction coil structure scheme_m(i.e. Δ T)_m＝max(ΔT_v，ΔT_h) M maximum temperature differences DeltaT) are obtained_m。

Eighth step, selecting m maximum temperature differences Delta T_mIs the set of structural parameters R 'corresponding to the minimum value in'_C1、R′_Cn、H′_Cn、l′_C(ii) a And make R_C1Equal to R 'in the set of structural parameters'_C1Let R be_CnEqual to R 'in the set of structural parameters'_CnLet H stand for_CnIs equal to H 'in the set of structural parameters'_CnLet l be_CIs equal to l 'in the set of structural parameters'_C(ii) a H is to be_Cn、l_CAnd d is substituted into the formula:n is calculated.

The simulation analysis described above shows that the induction coil 1 in this embodiment is a 10-turn hollow spiral copper coil, and the winding radius R of the first-turn hollow spiral copper coil of the induction coil 1_C1Winding radius R of tenth turn hollow spiral copper coil of induction coil 1 equal to 76mm_C10Equal to 103mm, height H of induction coil 1_CnEqual to 208mm, and the longitudinal distance l between two adjacent turns of the hollow spiral copper coil_CEqual to 12 mm; the winding radius R of the second turn hollow spiral copper coil of the induction coil 1_C2Equal to 79mm, and the winding radius R of the third turn hollow spiral copper coil of the induction coil 1_C3Equal to 82mm, and the winding radius R of the fourth turn hollow spiral copper coil of the induction coil 1_C4Equal to 85mm, and the winding radius R of the fifth turn hollow spiral copper coil of the induction coil 1_C5Equal to 88mm, and the winding radius R of the sixth turn hollow spiral copper coil of the induction coil 1_C6Equal to 91mm, and the winding radius R of the seventh turn hollow spiral copper coil of the induction coil 1_C7Equal to 94mm, and the winding radius R of the eighth turn hollow spiral copper coil of the induction coil 1_C8Equal to 97mm, induction lineWinding radius R of ninth turn hollow spiral copper coil of ring 1_C9Equal to 100 mm. The induction coil 1 is wound clockwise from top to bottom.

When the same motor hot jacket is heated, the parameter pairs of the induction coil in the embodiment and the existing induction coil uniformly wound with the same width at the upper part and the lower part and the same longitudinal distance are as follows:

scheme(s)	Maximum axial temperature difference	Maximum radial temperature difference
			Induction coil uniformly wound at equal longitudinal intervals and with same width from top to bottom	145℃	19℃
Frustum-shaped induction coil	10℃	8℃

When the existing induction coil which is uniformly wound at the same width from top to bottom and at the same longitudinal distance is heated, the maximum axial temperature difference generated on the surface of a motor hot jacket is 145 ℃, the maximum radial temperature difference is 19 ℃, and the highest temperature is generated at the T-shaped process groove part at the top end. In the heating process, because the surface temperature distribution of the motor hot jacket is uneven, the induction coil continuously heats the motor hot jacket to raise the temperature before the lowest temperature reaches 160 ℃, so that the T-shaped process groove part of the motor hot jacket has a local over-temperature ablation phenomenon, and the service life of the motor hot jacket is influenced.

When the frustum-shaped induction coil in this embodiment is heated, the maximum axial temperature difference generated on the surface of the motor hot jacket is 10 ℃, and the maximum radial temperature difference is 8 ℃. In the transient heating process, the magnetic field distribution on each surface of the motor thermal jacket is very uniform, the temperature rise rate is basically kept consistent, the motor thermal jacket is uniformly heated, the uniformity of the thermal deformation of the motor thermal jacket material is ensured to a great extent, the reliability of electromagnetic induction heating is improved, the problem of equipment ablation caused by nonuniform local heating is avoided, and the service life of the motor thermal jacket is prolonged. When the method is applied to occasions with high requirement on temperature uniformity of the motor hot jacket, the final yield and the reliability are obviously improved.