A permanent magnet synchronous variable frequency motor for tractors

Abstract

This utility model relates to the field of synchronous variable frequency motor technology, and provides a permanent magnet synchronous variable frequency motor for tractors, including a stator and a rotor. The rotor adopts a hollow permanent magnet structure, with multiple permanent magnets evenly embedded in the rotor core along the circumferential direction. Multiple weight-reduction slots are provided on the outer side of the rotor core. Weight-reduction holes are provided on the rotor laminations, and the motor's drive shaft has no shaft-mounted fan structure. Compared with asynchronous motors, the permanent magnet motor provided by this utility model has a smaller volume for the same power, and the weight reduction measures make the permanent magnet synchronous motor for tractors lighter and more compact. Because the rotor of the permanent magnet motor uses permanent magnets, the overall current of the motor is reduced, and the heat generated by the motor is also reduced. Furthermore, removing the fan connected to the drive shaft further reduces the motor's weight. The use of a permanent magnet motor for tractors reduces copper losses and improves overall operating efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of synchronous variable frequency motor technology, and relates to a permanent magnet synchronous variable frequency motor for tractors. Background Technology

[0002] Tractors, as highly efficient agricultural machinery, are widely used in farmland operations. With the advancement of science and technology in my country and the increasing prominence of agriculture, the importance of tractors in modern agricultural production is growing daily. Traditional tractors generally use internal combustion engines as their power source, driving the wheels and implements through mechanical or hydraulic transmission. Although internal combustion engines have the significant advantage of high torque output, they also have many drawbacks: 1. Low energy efficiency: The energy utilization rate of internal combustion engines is generally below 40%, resulting in significant energy waste; 2. Prominent environmental pollution: The exhaust gases emitted by internal combustion engines contain large amounts of pollutants such as nitrogen oxides (NOx), which contradicts the future development concept of green agriculture; 3. Complex and costly maintenance: Traditional agricultural machinery relies on complex structures such as fuel systems, cooling systems, and exhaust gas treatment devices, leading to high maintenance costs.

[0003] Currently, a large number of tractors still use internal combustion engine technology. Even if some tractors use variable frequency asynchronous motors as drive devices, there are still problems of low efficiency and serious energy waste. Specifically, there are the following problems: (1) Existing asynchronous motors have excessively high rotor copper losses, which cause serious heat generation during operation and make heat dissipation difficult. Although there is an independent fan connected to the shaft inside the motor to assist in heat dissipation, this increases the overall weight of the motor and reduces the system efficiency. (2) Existing asynchronous motors have excessively high rotor copper losses, which cause serious heat generation during operation and make heat dissipation difficult. Although there is an independent fan connected to the shaft inside the motor to assist in heat dissipation, this increases the overall weight of the motor and reduces the system efficiency. (3) At present, most tractors still use internal combustion engines or asynchronous motors as power sources. The environmental pollution caused by internal combustion engines and the heat generation during operation of asynchronous motors will accelerate the aging and damage of motor insulation materials, cause bearing lubrication failure, and cause rotor deformation, which in turn leads to a decrease in motor efficiency, an increase in energy consumption, and a shortening of equipment lifespan. (4) The efficiency of asynchronous motors used in tractors decreases significantly under light load conditions, making it difficult to meet the operational needs of tractors with frequent start-stop and load changes.

[0004] In view of the above, this utility model is hereby proposed. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a permanent magnet synchronous variable frequency motor for tractors. Compared with asynchronous motors, permanent magnet motors with the same power have a smaller volume, and through weight reduction measures, they are made lighter and more compact. Because the rotor of the permanent magnet motor uses permanent magnets, the overall current of the motor is reduced, and the heat generated by the motor is also reduced. Moreover, removing the fan connected to the drive shaft will further reduce the weight of the motor. The use of permanent magnet motors for tractors will reduce the copper loss of the motor and improve the overall operating efficiency.

[0006] To achieve the above-mentioned functions, this utility model provides the following technical solution:

[0007] This utility model provides a permanent magnet synchronous variable frequency motor for tractors, including a stator and a rotor. The rotor adopts a hollow permanent magnet structure, and multiple permanent magnets are uniformly embedded in the rotor core along the circumferential direction. Multiple weight-reducing slots are provided on the outer side of the rotor core. Weight-reducing holes are provided on the laminations of the rotor. The drive shaft of the motor has no shaft-driven fan structure.

[0008] Furthermore, the weight-reducing groove is a trapezoidal groove with a depth of 1 / 3 to 1 / 2 of the rotor core thickness and a bottom width of 0.6 to 0.8 times the opening width.

[0009] Furthermore, the weight-reducing holes are circular holes, evenly distributed on the outer pitch circle of the lamination.

[0010] Furthermore, the diameter of the weight-reducing hole is 5-10 mm, and a pair of permanent magnet poles are provided between two adjacent weight-reducing holes.

[0011] Furthermore, the axial length of the motor is ≤495mm and the maximum diameter is ≤540mm.

[0012] Furthermore, the permanent magnet is a cobalt-saturated permanent magnet, with 6 to 12 permanent magnets per pole, preferably 10 permanent magnets per pole.

[0013] Furthermore, the space between two adjacent permanent magnets is filled with adhesive, which includes epoxy resin structural adhesive, acrylic structural adhesive, and polyurethane adhesive, etc., and has a certain degree of high temperature resistance.

[0014] Compared with the prior art, the technical solution provided by this utility model has the following beneficial effects:

[0015] 1. The permanent magnet synchronous variable frequency motor for tractors provided by this utility model reduces the size of the tractor drive motor. Under the same installation size, it can output higher power, improve the speed of tractor sowing, walking and tilling, and has great application value for tractors with small space and high power requirements.

[0016] 2. The permanent magnet synchronous variable frequency motor for tractors provided by this utility model, through the updating of the rotor assembly structure, has weight reduction grooves processed on the rotor core and weight reduction holes provided on the rotor laminations, which greatly reduces the weight of the motor, reduces the energy consumption of the motor, and improves the balance and rigidity of the motor.

[0017] 3. The permanent magnet synchronous variable frequency motor for tractors provided by this utility model adopts a hollow permanent magnet structure, which ensures better heat dissipation of the motor, significantly reduces the motor temperature, reduces the temperature rise under the same working conditions by nearly 30%, and avoids a series of problems caused by insufficient heat dissipation.

[0018] 4. The permanent magnet synchronous variable frequency motor for tractors provided by this utility model reduces the copper loss of the motor rotor by using a permanent magnet rotor structure, which can improve the efficiency of the motor under all working conditions. Tests have shown that the use of a permanent magnet rotor improves the overall efficiency of the motor by about 5%.

[0019] 5. The permanent magnet synchronous variable frequency motor for tractors provided by this utility model removes the shaft fan on the right side of the original asynchronous motor, ultimately reducing the motor weight by approximately 20%. Attached Figure Description

[0020] The accompanying drawings are incorporated in and form part of this specification, and together with the description, serve to explain the principles of this invention.

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a side view of an asynchronous motor used in tractors in the prior art.

[0023] Figure 2 This is a front cross-sectional view of an asynchronous motor used in tractors in the prior art.

[0024] Figure 3 This is a front cross-sectional view of the permanent magnet synchronous variable frequency motor for tractors according to this utility model.

[0025] Figure 4 This is a side view of the permanent magnet synchronous variable frequency motor for tractors according to the present invention.

[0026] Figure 5 for Figure 3 Enlarged view of part A of the structure of the permanent magnet synchronous variable frequency motor for tractors from Zhongben Utility Model;

[0027] Figure 6 This is a schematic diagram of the structure of the permanent magnet synchronous variable frequency motor for tractors of this utility model, in which a weight reduction groove is provided on the rotor.

[0028] Figure 7 This is a schematic diagram of the rotor of the permanent magnet synchronous variable frequency motor for tractors of this utility model, which has weight reduction holes.

[0029] Figure 8 This is a schematic diagram of the shaftless fan structure of the permanent magnet synchronous variable frequency motor for tractors according to this utility model.

[0030] Wherein: 1-Stator; 2-Rotor; 3-Weight reduction slot; 4-Laminator; 5-Weight reduction hole; 6-Drive shaft; 7-Right side winding. Detailed Implementation

[0031] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this invention. Rather, they are merely examples consistent with some aspects of this invention as detailed in the appended claims.

[0032] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0033] See Figures 1-2 As shown, in the prior art, the length and maximum diameter of the asynchronous motor used in tractors are 644 mm and 624.37 mm, respectively. See also... Figures 3-4 As shown, under the same power, the length and diameter of the permanent magnet synchronous variable frequency motor of this invention are 495mm and 540mm, respectively. That is, the axial length of the permanent magnet synchronous variable frequency motor of this invention is ≤495mm, and the maximum diameter is ≤540mm. Compared with the asynchronous motors used in tractors in the prior art, the overall size is greatly reduced, which can effectively utilize the space in the tractor.

[0034] According to an embodiment of this utility model, see Figures 5-7As shown, the permanent magnet synchronous frequency converter of this invention includes a housing. A stator 1 is fixedly installed in the middle of the housing cavity, and a rotor 2 is provided on the inner side of the stator 1. A drive shaft 6 is installed on the rotor 2. The rotor 2 adopts a hollow permanent magnet structure, with multiple permanent magnets uniformly embedded in the rotor core along the circumferential direction. Multiple weight-reducing slots 3 are symmetrically opened on both sides of the rotor core along the axial direction, and the multiple weight-reducing slots 3 are uniformly arranged along the circumferential direction of the rotor core. Preferably, the weight-reducing slots 3 are set as trapezoidal grooves, with a depth of 1 / 3 to 1 / 2 of the thickness of the rotor core, and a bottom width of 0.6 to 0.8 times the opening width. Weight-reducing holes 5 are provided on the laminations 4 of the rotor 2. The weight-reducing holes 5 are circular holes, uniformly distributed on the outermost pitch circle of the laminations 4. The diameter of the weight-reducing holes 5 is 5 to 10 mm, and a pair of permanent magnet poles are provided between two adjacent weight-reducing holes 5. It should be noted that the weight reduction groove 3 and weight reduction hole 5 should not affect the stiffness of rotor 2.

[0035] The purpose of setting up the weight reduction groove 3 and the weight reduction hole 5 is to significantly reduce the weight of the rotor 2, improve the balance and rigidity of the motor, and thus minimize the weight of the motor.

[0036] According to an embodiment of this utility model, the rotor 2 adopts a hollow permanent magnet structure, which reduces the copper loss of the motor and improves the efficiency of the motor under complex operating conditions. The permanent magnet in this utility model is a cobalt-saturated permanent magnet, with 6 to 12 permanent magnets per pole, preferably 10, but 6, 7, 8, 9, 11, and 12 can also be selected. The number of permanent magnets can be increased or decreased based on specific operating conditions, all of which fall within the protection scope of this utility model.

[0037] According to an embodiment of this utility model, the space between two adjacent permanent magnets is filled with adhesive. The adhesives that can be selected include epoxy resin structural adhesive, acrylic structural adhesive, and polyurethane adhesive, etc., and must have certain high temperature resistance.

[0038] According to an embodiment of this utility model, see Figure 8 As shown, there is no shaft-driven fan structure on the drive shaft 6 of the motor, while Figure 8 The diagram shows the structure of the drive shaft 6 corresponding to the right winding 7 of the motor of this invention, without a shaft and equipped with a fan. According to the drawings, this fan can be removed during manufacturing; the purpose of this removal is to reduce the motor weight by approximately 20%.

[0039] The above description is merely a specific embodiment of this utility model, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this utility model.

[0040] It should be understood that this utility model is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of this utility model is limited only by the appended claims.

Claims

1. A permanent magnet synchronous variable frequency motor for tractors, comprising a stator (1) and a rotor (2), characterized in that, The rotor (2) adopts a hollow permanent magnet structure, and multiple permanent magnets are uniformly embedded in the rotor core along the circumferential direction. Multiple weight-reducing grooves (3) are provided on the outer side of the rotor core. Weight-reducing holes (5) are provided on the laminations (4) of the rotor (2). The drive shaft (6) of the motor has no shaft-driven fan structure.

2. The permanent magnet synchronous variable frequency motor for tractor according to claim 1, characterized in that, The weight reduction groove (3) is a trapezoidal groove with a depth of 1 / 3 to 1 / 2 of the rotor core thickness and a bottom width of 0.6 to 0.8 times the groove opening width.

3. The permanent magnet synchronous variable frequency motor for tractors according to claim 1, characterized in that, The weight reduction holes (5) are circular holes, evenly distributed on the outer pitch circle of the lamination (4).

4. The permanent magnet synchronous variable frequency motor for tractors according to claim 3, characterized in that, The diameter of the weight reduction hole (5) is 5-10 mm, and a pair of permanent magnet poles are provided between two adjacent weight reduction holes (5).

5. The permanent magnet synchronous variable frequency motor for tractors according to claim 1, characterized in that, The axial length of the motor is ≤495mm and the maximum diameter is ≤540mm.

6. The permanent magnet synchronous variable frequency motor for tractors according to claim 1, characterized in that, The permanent magnet is a cobalt-saturated permanent magnet, and there are 6 to 12 permanent magnets per pole.

7. The permanent magnet synchronous variable frequency motor for tractors according to claim 1, characterized in that, Adhesive is used to fill the space between two adjacent permanent magnets.

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