A pressure-resistant motor housing and its processing method

Abstract

The present invention discloses a voltage-resistant motor housing and its processing method. A double-layer motor housing structure is used. First, according to the usage environment of the motor, the corresponding materials for the outer housing and the inner housing are selected, and rough machining is performed on the inner housing and the outer housing, and process holes are opened. The inner housing and the outer housing are assembled by interference fit. Then, spiral grooves for cooperating with the outer periphery of the stator for stator cooling are machined on the inner surface of the inner housing, and then finish machining of the inner hole of the inner housing is carried out. The machining size of the inner hole of the inner housing is determined according to the size of the motor stator. The motor housing of the present invention adopts a double-layer housing structure. The outer housing maintains the structural strength of the motor housing, and the inner housing fixes the internal stator components. It can be compatible with different sizes of motor structures. The interference fit assembly structure can still keep the inner housing and the outer housing closely attached to each other under high-temperature and high-pressure environments without detachment, improving the reliability of the motor housing.

Description

Technical Field

[0001] The present invention relates to the technical field of motor processing, and particularly relates to a pressure-resistant motor housing and a processing method thereof. Background Art

[0002] In a waste heat utilization system, an expander is often used in cooperation with an organic medium to convert chemical energy into mechanical energy, and then by connecting an external power generation device or directly connecting a device to the expander, the utilization of the converted mechanical energy is realized; the expander drives the impeller to rotate through a high-temperature and high-pressure organic medium gas to achieve energy conversion, which makes the use environment of the motor relatively harsh. The existing motor housings use aluminum materials or steel materials; for the aluminum material motor housing, the strength requirements cannot be met under the same thickness; for the steel material motor housing, due to the large wall thickness of the housing, standard seamless steel pipes cannot meet the requirements, and precision casting is required, but the casting defects cannot be controlled, and the airtightness and safety requirements cannot be achieved. Summary of the Invention

[0003] Technical Objective: Aiming at the deficiency that in the high-temperature and high-pressure environment of the motor in the existing expander system, ordinary aluminum shell materials cannot meet the strength requirements, and the motor housing made of steel materials needs to be cast, resulting in the inability to meet the airtightness and safety requirements of the motor housing in the high-temperature and high-pressure environment, the present invention discloses a pressure-resistant motor housing and a processing method thereof that can ensure the airtightness and safety of the motor housing in the high-temperature and high-pressure environment, and at the same time the structural strength meets the requirements.

[0004] Technical Solution: To achieve the above technical objective, the present invention adopts the following technical solutions:

[0005] A pressure-resistant motor housing includes an inner housing and an outer housing arranged concentrically. The inner housing and the outer housing are in interference fit. The inner hole of the inner housing matches the outer diameter of the stator. A spiral groove for cooperating with the outer surface of the stator to form a refrigerant flow channel is provided on the side wall of the inner hole of the inner housing.

[0006] Preferably, the inner housing of the present invention is made of aluminum material, and the outer housing is cut and prefabricated from a seamless steel pipe, and the inner housing is installed in the outer housing by a hot sleeve method.

[0007] Preferably, the interference amount between the inner housing and the outer housing of the present invention is greater than the maximum difference between the deformation amounts of the inner housing and the outer housing under the motor working conditions.

[0008] The present invention provides a processing method for a pressure-resistant motor housing for processing the above motor housing, including the steps:

[0009] S01. According to the use environment of the motor, select the corresponding materials for the outer housing and the inner housing, rough process the inner housing and the outer housing, and open process holes. The inner housing and the outer housing are assembled by interference fit;

[0010] S02. Machine spiral grooves on the inner surface of the inner housing for cooperating with the outer periphery of the stator to cool the stator, and then perform finish machining on the inner hole of the inner housing. The machining size of the inner hole of the inner housing is determined according to the size of the motor stator.

[0011] Preferably, in step S01 of the present invention, the interference amount between the inner housing and the outer housing is determined according to the maximum difference in deformation of the materials of the inner housing and the outer housing under all operating conditions of the motor.

[0012] Preferably, the determination process of the maximum difference of the present invention includes: considering the temperature range t1 - t2 and the internal pressure range p1 - p2 of the motor housing in the motor operating conditions; the deformation amount of the housing under thermal action In the formula represents the diameter of the housing before deformation, with the unit of mm, ε represents the material expansion coefficient, ΔT represents the temperature difference during deformation compared with the temperature before deformation, with the unit of °C; the radial deformation of the housing under pressure In the formula: Δr represents the radial displacement (m) generated by the housing along the direction of the acting pressure; p represents the acting pressure, with the unit of Pa; E represents the elastic modulus of the housing material; r1 represents the inner diameter of the housing, with the unit of mm; r represents the diameter of the housing before deformation at the position where the housing deformation is calculated, r2 represents the outer diameter of the housing, with the unit of mm; μ is the Poisson's ratio; the interference amount X > Δs2 - Δs1 - Δr1, where Δs2 represents the deformation amount of the inner housing under thermal action, Δs1 represents the deformation amount of the outer housing under thermal action, and Δr1 represents the deformation amount of the inner hole of the outer housing under thermal action.

[0013] Preferably, the temperature value and pressure value for calculating the maximum difference of the present invention are selected according to the material expansion coefficients between the outer housing and the inner housing. When the material expansion coefficient of the outer housing is greater than that of the inner housing, the highest working pressure and temperature are selected. When the material expansion coefficient of the outer housing is less than that of the inner housing, the lowest working pressure and temperature are selected.

[0014] Preferably, in step S02 of the present invention, the process of machining the spiral grooves includes: machining a ring groove at the positions of the inlet and outlet of the spiral grooves, which serves as the starting point and the retracting point during the machining of the spiral grooves.

[0015] Preferably, when drilling holes in the flange welded to the motor housing, according to the offset generated by welding, the drilling position is processed by borrowing the position to make the bolt holes symmetric about the center of the flange.

[0016] Preferably, the offset machining process of the present invention includes: fixing the motor housing on the machine tool, establishing a three-dimensional coordinate system based on the fixed position of the motor housing, and machining the inner hole of the motor housing using the absolute coordinates within the three-dimensional coordinate system; determining the deviation of the flange welded to the motor housing relative to the center line of the motor housing through laser ranging, setting the offset machining amount of the machine tool to half of the deviation amount, and performing symmetric drilling on the flange.

[0017] Preferably, when machining the inner hole of the motor housing of the present invention, a process inner hole with a width of 20 mm is machined at the minimum of the inner hole diameter. When turning around for machining, the process inner hole is used as the machining reference for turning around.

[0018] Beneficial effects: The pressure-resistant motor housing and its processing method provided by the present invention have the following beneficial effects:

[0019] 1. The motor housing of the present invention adopts a double-layer housing structure. The outer housing maintains the structural strength of the motor housing, and the inner housing fixes the internal stator components, enabling compatibility with different sizes of motor structures.

[0020] 2. An interference fit assembly structure is used between the inner housing and the outer housing of the present invention. In a high-temperature and high-pressure environment, the inner housing and the outer housing can still maintain close fit and will not separate, improving the reliability of the motor housing.

[0021] 3. The outer housing of the present invention adopts seamless steel pipe, and the inner housing adopts an aluminum structure, eliminating the need for separate casting to fit the size of the motor, avoiding the casting defect problems of the cast housing, and meeting the strength requirements and airtightness requirements in the high-temperature and high-pressure environment of the expander.

[0022] 4. When performing interference fit between the inner and outer housings of the present invention, the interference amount is set according to the deformation difference between the inner and outer housings generated under the operating conditions of the motor, ensuring that the inner housing and the outer housing are always in close contact and will not separate under the normal use environment of the motor.

[0023] 5. When machining the inner hole of the motor housing of the present invention, the spiral groove is machined first, and then the inner hole is finish-machined, ensuring the cylindricity of the inner hole of the motor housing.

[0024] 6. During the machining process of the spiral groove of the present invention, corresponding ring grooves are opened at both ends of the spiral groove, and the ring grooves are used as tool retraction during spiral machining, facilitating the operation of the machining personnel.

[0025] 7. For the drilling of the flange welded on the motor housing of the present invention, an offset machining method is adopted, fully considering the structural deformation caused by welding, ensuring that the bolt holes on the flange surface are symmetric with each other, avoiding the occurrence of dangerous cross-sections, and ensuring the structural strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0027] Figure 1 It is a schematic structural diagram of the pressure-resistant motor housing of the present invention;

[0028] Among them, 1 - inner housing, 2 - outer housing, 3 - spiral groove. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be more clearly and completely described below by way of a preferred embodiment in conjunction with the drawings, but the present invention is not limited to the scope of the described embodiments.

[0030] As Figure 1 shown, a pressure-resistant motor housing disclosed by the present invention includes a concentrically arranged inner housing 1 and an outer housing 2. The inner housing 1 and the outer housing 2 are in interference fit. The inner hole of the inner housing 1 matches the outer diameter of the stator. A spiral groove 3 for forming a refrigerant flow path in cooperation with the outer surface of the stator is provided on the side wall of the inner hole of the inner housing 1.

[0031] Specifically, the inner housing 1 of the present invention is made of aluminum material, and the outer housing 2 is prefabricated by cutting seamless steel pipe. The inner housing 1 is installed in the outer housing 2 in a hot-sleeved manner. The interference amount between the inner housing 1 and the outer housing 2 is greater than the maximum difference in the deformation amounts of the inner housing and the outer housing under the operating conditions of the motor.

[0032] The present invention also provides a processing method for processing the above-mentioned pressure-resistant motor housing, including steps;

[0033] S01. According to the use environment of the motor, select the corresponding materials for the outer housing and the inner housing, rough-process the inner housing and the outer housing, and open process holes. The inner housing and the outer housing are assembled by interference fit;

[0034] S02. Process spiral grooves on the inner surface of the inner housing for cooling the stator in cooperation with the outer circumference of the stator, and then perform finish machining on the inner hole of the inner housing. The machining size of the inner hole of the inner housing is determined according to the size of the motor stator. The interference amount between the inner housing and the outer housing is determined according to the maximum difference in deformation of the inner housing and the outer housing materials under all operating conditions of the motor, so as to always maintain a tight fit between the inner housing and the outer housing during the operation of the motor and maintain the stability of the structure.

[0035] In step S02, the process of processing the spiral groove includes: machining a ring groove at the inlet and outlet positions of the spiral groove, which serves as the starting point and the retracting point during the machining of the spiral groove, and simplifies the machining difficulty.

[0036] The process for determining the maximum difference includes: considering, in the operating conditions of the motor, the temperature range t1 - t2 of the motor housing and the internal pressure range p1 - p2; the deformation amount of the housing under thermal action In the formula represents the diameter of the housing before deformation, with the unit of mm, ε represents the material expansion coefficient, ΔT represents the difference in temperature during deformation compared to the temperature before deformation, with the unit of °C; the radial deformation of the housing under pressure action In the formula: Δr represents the radial displacement (m) generated by the housing along the direction of the acting pressure; p represents the acting pressure, with the unit of Pa; E represents the elastic modulus of the housing material; r1 represents the inner diameter of the housing, with the unit of mm; r represents the diameter of the housing before deformation at the location where the deformation of the housing is calculated, r2 represents the outer diameter of the housing, with the unit of mm; μ is the Poisson's ratio; the interference amount X > Δs2 - Δs1 - Δr1, where Δs2 represents the deformation amount of the inner housing under thermal action, Δs1 represents the deformation amount of the outer housing under thermal action, and Δr1 represents the deformation amount of the inner hole of the outer housing under thermal action. The temperature value and pressure value for calculating the maximum difference are selected according to the material expansion coefficients between the outer housing and the inner housing. When the material expansion coefficient of the outer housing is greater than that of the inner housing, the highest working pressure and temperature are selected. When the material expansion coefficient of the outer housing is less than that of the inner housing, the lowest working pressure and temperature are selected.

[0037] In a specific embodiment of the present invention, the outer housing is made of Q235 steel, and the inner housing is made of aluminum. Due to the structure of aluminum, its expansion coefficient is greater than that of the steel structure. When the motor is heated, the inner and outer housings interact under the combined action of the internal pressure and the external high-temperature environment, making the deformation amount of the inner housing greater than that of the outer housing. In the high-temperature environment of the expander, it can make the inner housing fit more tightly with the outer housing, ensuring the stable operation of the motor in the high-temperature environment.

[0038] After determining the inner hole size according to the motor stator, the corresponding inner and outer housing sizes can be selected according to the motor operating conditions, and the outer housing is heated so that the inner housing can be smoothly installed.

[0039] For structures such as connection flanges on the motor that need to be docked with equipment in the expander system, after rough machining the outer housing to remove the fatigue layer and hardened layer, welding is directly carried out. After welding is completed, semi-finishing machining is carried out on the inner hole of the outer housing, thereby avoiding the problem that the internal weld of the housing is not easy to clean due to welding, affecting the assembly of the inner housing and the outer housing; then, the inner housing is installed by the hot sleeve method. After the inner housing fits tightly with the outer housing, machining of the inner hole is carried out.

[0040] First, the spiral groove is machined. A ring groove is machined at the positions of the inlet and outlet of the spiral groove, which serves as the starting point and the retracting point during the machining of the spiral groove. Finally, the inner hole surface is machined to ensure the cylindricity of the inner hole of the inner housing and prevent the appearance of an elliptical shape on the inner hole surface. Since the inner hole has different diameters, after machining the smallest hole diameter, it is necessary to turn the workpiece around from the other side of the motor housing. To ensure the concentricity of the machining, when machining the inner hole of the motor housing in the present invention, a process inner hole with a width of 20 mm is machined at the smallest part of the inner hole diameter. When turning the workpiece around for machining, the process inner hole is used as the machining reference for turning the workpiece around, so as to ensure the coaxiality of the inner hole machined after turning the workpiece around.

[0041] When machining the inner hole of the motor housing, the motor housing needs to be fixed on the machine tool, and a three-dimensional coordinate system is established according to the fixed position of the motor housing. When drilling holes in the flange welded on the motor housing, according to the offset generated by welding, the drilling position is processed by borrowing position, so that the bolt holes are symmetric about the center of the flange. The process of borrowing position includes: fixing the motor housing on the machine tool, establishing a three-dimensional coordinate system according to the fixed position of the motor housing, and machining the inner hole of the motor housing using the absolute coordinates in the three-dimensional coordinate system; the flange welded on the motor housing determines the deviation of the flange relative to the center line of the motor housing through laser ranging, sets the amount of position borrowing of the machine tool as half of the deviation amount, and performs symmetric drilling on the flange. By this method, the problem of asymmetric drilling on the flange surface is solved, the structural strength is ensured, and the situation of a dangerous cross-section is avoided.

[0042] For the motor housing structure obtained by using the motor housing processing method of the present invention, the outer housing can directly use a finished seamless steel pipe, and the structural strength and performance can be guaranteed. The interference-fitted inner housing can adjust the inner hole so as to fix the motor stator. While ensuring the performance of the housing, the overall weight can be reduced, and the problem of casting defects in precision casting can also be avoided, meeting the use requirements of the expander in a high-temperature and high-pressure environment.

[0043] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A processing method for a voltage-resistant motor housing, characterized in that, The pressure-resistant motor housing includes an inner housing (1) and an outer housing (2) that are concentrically arranged. The inner housing (1) and the outer housing (2) are in interference fit. The inner diameter of the inner housing (1) matches the outer diameter of the stator. A spiral groove (3) for forming a refrigerant flow path in cooperation with the outer surface of the stator is provided on the side wall of the inner hole of the inner housing (1). The processing method includes the steps: S01. According to the usage environment of the motor, select the corresponding materials for the outer housing and the inner housing, rough-process the inner housing and the outer housing, and open process holes. The inner housing and the outer housing are assembled by interference fit. S02. Process a spiral groove on the inner surface of the inner housing for cooling the stator in cooperation with the outer circumference of the stator, and then perform finish machining on the inner hole of the inner housing. The machining size of the inner hole of the inner housing is determined according to the size of the motor stator. In step S01, the interference amount between the inner housing and the outer housing is determined according to the maximum difference in deformation of the inner housing and the outer housing materials under all operating conditions of the motor. The determination process of the maximum difference includes: considering the temperature range t1 - t2 and the internal pressure range p1 - p2 of the motor housing under the operating conditions of the motor; the deformation amount of the housing under thermal action In the formula represents the diameter of the housing before deformation, with the unit of mm, ε represents the material expansion coefficient, and ΔT represents the temperature difference between the temperature during deformation and the temperature before deformation, with the unit of °C; the radial deformation of the housing under pressure In the formula: Δr represents the radial displacement (m) generated by the housing along the direction of the acting pressure; p represents the acting pressure, with the unit of Pa; E represents the elastic modulus of the housing material; r1 represents the inner diameter of the housing, with the unit of mm; r represents the diameter before deformation at the deformed part of the calculated housing, r2 represents the outer diameter of the housing, with the unit of mm; μ is the Poisson's ratio; the interference amount X > Δs2 - Δs1 - Δr1, where Δs2 represents the deformation amount of the inner housing under thermal action, Δs1 represents the deformation amount of the outer housing under thermal action, and Δr1 represents the deformation amount of the inner hole of the outer housing under thermal action.

2. The processing method of a voltage-resistant motor housing according to claim 1, characterized in that, The temperature value and pressure value for calculating the maximum difference are selected according to the material expansion coefficients between the outer housing and the inner housing. When the material expansion coefficient of the outer housing is greater than that of the inner housing, the highest working pressure and temperature are selected. When the material expansion coefficient of the outer housing is less than that of the inner housing, the lowest working pressure and temperature are selected.

3. A method for machining a voltage-resistant motor housing according to claim 1, characterized in that, In step S02, the process of machining the spiral groove includes: machining a ring groove at the inlet and outlet positions of the spiral groove, which serves as the starting point and the retracting point during the machining of the spiral groove; when drilling holes in the flange welded on the motor housing, according to the offset generated by welding, the drilling position is offset-processed so that the bolt holes are symmetric about the center of the flange.

4. A method for machining a pressure-resistant motor housing according to claim 3, characterized in that, The offset-processing process includes: fixing the motor housing on the machine tool, establishing a three-dimensional coordinate system according to the fixed position of the motor housing, and machining the inner hole of the motor housing using the absolute coordinates in the three-dimensional coordinate system; the flange welded on the motor housing determines the deviation of the flange relative to the center line of the motor housing through laser ranging, sets the offset-processing amount of the machine tool to half of the deviation amount, and performs symmetric drilling on the flange.

5. A method for machining a pressure-resistant motor housing according to claim 1, characterized in that, When machining the inner hole of the motor housing, a 20-mm-wide process inner hole is machined at the minimum of the inner hole diameter. When turning around for machining, the process inner hole is used as the machining reference for turning around.

6. A method for machining a pressure-resistant motor housing according to claim 1, characterized in that, The inner housing (1) is made of aluminum material, and the outer housing (2) is prefabricated by cutting seamless steel pipes. The inner housing (1) is inserted into the outer housing (2) in a hot-sleeved manner.

7. A method for machining a pressure-resistant motor housing according to claim 1, characterized in that, The interference amount between the inner housing (1) and the outer housing (2) is greater than the maximum difference in the deformation amounts of the inner housing and the outer housing under the operating conditions of the motor.

Images