A large-axle-weight direct-drive permanent-magnet traction motor

Abstract

The application relates to a permanent magnet traction motor, in particular to the motor as a driving unit applied to a self-traveling track running vehicle in metallurgy, mining and energy exploitation, and in particular to a large-axle-weight direct-drive permanent magnet traction motor adopting a double-TRB back-to-back bearing structure. The traction motor is in an elongated type and is directly arranged along an axle, a stator assembly adopts a welding base + hot sleeve iron core winding structure, and one front end cover and one rear end cover are respectively arranged on both sides of the stator assembly and rely on the base stopper; one conical roller bearing is respectively arranged in the front end cover and the rear end cover, and the two conical roller bearings are back-to-back arranged; the stator assembly is supported on a motor rotor through the two conical roller bearings and relies on the front and rear end covers; the outer sides of the two conical roller bearings are respectively axially positioned and compressed through front and rear outer sealing rings which are assembled in an over-won manner; and the inner sides of the two conical roller bearings are respectively provided with one inner sealing ring for ensuring that the two conical roller bearings are in a reasonable axial clearance range during operation.

Description

Technical Field

[0001] This invention relates to a permanent magnet traction motor, and in particular, the motor is used as a drive unit in self-propelled rail vehicles carrying heavy axle loads of molten steel, ore, powder materials, etc. in metallurgical, mining, and energy extraction enterprises. Specifically, it is a heavy axle load direct-drive permanent magnet traction motor with a double tapered roller bearing back-to-back mounting bearing structure. Background Technology

[0002] Compared to locomotives operating on national railway trunk lines, the bogies of transfer vehicles owned by factories and mines are characterized by short wheelbases, small wheel diameters (φ820), heavy axle loads (up to 43t), thick axles (wheel disc position φ275, maximum outer diameter φ306), and high traction torque (starting torque up to 12000Nm, rated torque up to 7200Nm). The vast majority of these vehicles use diesel locomotives for traction, allowing materials to be transported alongside them. In recent years, with the green and environmentally friendly transformation of major enterprises, old diesel locomotives have been gradually phased out, and battery-powered, driverless, self-propelled vehicles have been adopted.

[0003] Existing technical solutions are as follows Figure 1 As shown, to provide traction power to the wheelset of a self-propelled vehicle, the traction motor's shaft is arranged parallel to the wheelset axle. The traction motor outputs torque through the shaft, and a driving pinion is installed at the end of the shaft. The driving pinion meshes with the driven gear to transmit traction power to the axle. The traction motor is bolted to the axle housing, which is mounted around the axle, via rolling bearings.

[0004] The disadvantages of the existing technology are: a) The traction motor is arranged parallel to the axle, which occupies a lot of space in the vehicle's wheelbase and is not conducive to the installation and layout of other accessories such as brakes and wiring.

[0005] b. A complete set of rolling bearings and axle housings need to be added to the axle, making the mechanical structure more complex and the failure rate higher.

[0006] c. The presence of gear transmission leads to transmission losses and low efficiency of the drive device.

[0007] Existing technical solution two is in Figure 1 Based on this, a direct drive transmission technology is adopted. A hollow drive bushing is fitted onto the axle, with a six-bar linkage mechanism installed at both ends of the hollow bushing. The traction motor also uses a hollow shaft instead of a solid shaft, arranged concentrically with the axle, with the traction motor rotor core mounted on the hollow shaft. End face teeth are provided on the end face of the hollow shaft of the traction motor, which mesh with the end face teeth on the six-bar linkage mechanism at one end of the hollow bushing, ultimately achieving the following torque transmission path: Traction motor hollow shaft → one end six-link transmission mechanism → hollow shaft sleeve → other end six-link transmission mechanism → traction power is generated on the other end wheel.

[0008] Disadvantages of existing technology 2: a. The traction motor is arranged concentrically with the axle, which occupies less space in the vehicle's wheelbase. However, due to the use of two layers of hollow axles and hollow axle sleeves, the radial space occupied is relatively large. For self-propelled vehicles with large axle loads and small wheel diameters, an excessively large outer diameter of the traction motor will lead to exceeding the clearance limits.

[0009] b. A complete set of hollow bushings and a six-bar linkage transmission mechanism need to be added to the axle, making the structure relatively complex.

[0010] c. This structure has a relatively weak ability to withstand line impact and vibration loads, and is suitable for situations where the line is in good working condition. Summary of the Invention

[0011] To address the technical challenges of limited space on the axle under the bogie of self-propelled vehicles in factories and mines, harsh track impact and vibration conditions, and high heat dissipation requirements, this invention provides a high axle load direct-drive permanent magnet traction motor with a double tapered roller bearing back-to-back mounting bearing structure.

[0012] This invention is achieved using the following technical solution: a high-axle-load direct-drive permanent magnet traction motor with a double tapered roller bearing back-to-back mounting structure. The traction motor is slender and directly arranged along the axle. The stator assembly adopts a welded frame and a heat-shrinkable core winding structure. A front cover and a rear cover are mounted on each side of the stator assembly near the frame stop. A tapered roller bearing is installed inside each of the front and rear covers, with the two tapered roller bearings mounted back-to-back. The stator assembly is supported on the motor rotor by the two tapered roller bearings and the front and rear covers. The outer sides of the front and rear tapered roller bearings are axially positioned and clamped by a front outer sealing ring and a rear outer sealing ring with interference fit, respectively. An inner sealing ring is installed on the inner side of each of the front and rear tapered roller bearings to ensure that the two tapered roller bearings are within a reasonable axial clearance range during operation.

[0013] Furthermore, by calculating the relevant dimensional chain, the difference between the outer ring spacing and the inner ring spacing of the two tapered roller bearings is controlled to ensure that the two tapered roller bearings operate within a reasonable axial clearance range; the calculation formula is as follows: ΔC1 = L1 + L2*2 + B1 + B2 - T1 - T2 - L3 ΔC2=(0.7*(D1-D11)+0.8*(d11-d1)) / tan(16.25 / 180*π)+(0.7*(D2-D21)+0.8*(d21-d2)) / tan(16.25 / 180*π) C = ΔC1 - ΔC2; ΔC1 is the clearance formed by the axial dimension chain, L1 is the horizontal distance between the shoulders of the two bearings, L2 is the width of the inner sealing ring, B1 is the width of the inner ring of the rear bearing, B2 is the width of the inner ring of the front bearing, T1 is the assembly height of the rear bearing, T2 is the assembly height of the front bearing, and L3 is the distance between the shoulders of the two bearings. ΔC2 is the axial clearance change caused by the installation; D1 is the outer diameter of the rear bearing; D11 is the inner diameter of the rear bearing housing; d11 is the diameter at the inner ring seat of the rear axle; d1 is the inner diameter of the rear bearing; D2 is the outer diameter of the front bearing; D21 is the inner diameter of the front bearing housing; d21 is the diameter at the inner ring seat of the front axle; d2 is the inner diameter of the front bearing; C is the clearance value after assembly; L3 = machine base length - front bearing housing positioning dimension - rear bearing housing positioning dimension.

[0014] Furthermore, the base and the front and rear end covers form a fully enclosed structure; multiple heat dissipation ring ribs are arranged on the outer surface of the base; and multiple parallel heat dissipation ribs are arranged on the outer end faces of the front and rear end covers.

[0015] Furthermore, a rotary transformer for frequency conversion drive control of the permanent magnet traction motor is installed on the outside of the rear cover.

[0016] Furthermore, labyrinth seals are used between the bearing chambers of the front and rear end covers and the tapered roller bearings.

[0017] Furthermore, silicon steel laminations are directly arranged along the shaft of the rotor core of the motor rotor, and permanent magnets are inserted into the V-grooves of the rotor core and sealed with glue.

[0018] To meet the limited space requirements on the axle under the bogie of self-propelled vehicles in factories and mines, this invention designs a slender permanent magnet gearless direct drive traction motor.

[0019] Considering the characteristics of track-mounted self-propelled equipment, such as large traction tonnage (e.g., open steel ladles can weigh up to 240t), low speed (less than 20km / h), and hourly working hours, based on the aforementioned slender overall design, the electromagnetic compatibility of the motor is reasonably selected, and the use of fully enclosed natural heat dissipation cooling technology is considered.

[0020] Considering the poor track conditions, large traction tonnage, low-speed heavy loads, and severe impact and vibration conditions in most factories and mines, it is necessary to focus on bearing selection and load-bearing capacity calculation. Ultimately, a double tapered roller bearing (tapered roller bearing) back-to-back (with the small diameter ends of the tapered roller bearings adjacent) mounting structure was selected to effectively improve the axial load capacity of the motor.

[0021] The beneficial effects of the technical solution of this invention are as follows: The direct-drive permanent magnet traction motor of this invention has a simple structure and convenient assembly process. Moreover, the double tapered roller bearing has a strong axial load bearing capacity and the drive unit efficiency can reach more than 90%. It is very suitable for self-propelled track traction equipment inside heavy industrial plants and mines. Combined with new energy battery + inverter control + remote automatic control technology, it will make outstanding contributions to energy conservation, emission reduction, safety and environmental protection and green transformation and development of major enterprises. Attached Figure Description

[0022] Figure 1 A schematic diagram of an existing drive unit structure with the traction motor and axle arranged in parallel.

[0023] Figure 2 A schematic diagram of the cross-sectional structure of the direct-drive permanent magnet traction motor of this invention.

[0024] Figure 3 A schematic diagram of the main structure of the direct-drive permanent magnet traction motor of this invention.

[0025] Figure 4 A side view of the direct-drive permanent magnet traction motor of this invention.

[0026] Figure 5 One of the related dimensional illustrations for the bearing assembly example of the double tapered roller bearing of the present invention.

[0027] Figure 6 The second illustration of the relevant dimensions in the calculation example of the double tapered roller bearing of this invention.

[0028] Figure 7 A three-dimensional structural diagram of the direct-drive permanent magnet traction motor of this invention.

[0029] 1-Rear end cover, 2-Stator assembly, 3-Front end cover, 4-Front outer sealing ring, 5-Tap roller bearing, 6-Inner sealing ring (axial dimension matching), 7-Shaft, 8-Permanent magnet, 9-Rotor core, 10-Rear outer sealing ring, 11-Rotary transformer, 12-Heat dissipation ring rib, 13-Parallel heat dissipation rib, 14-Traction motor, 15-Driving pinion, 16-Driven gear, 17-Gearbox, 18-Axle. Detailed Implementation

[0030] This invention relates to a slender permanent magnet direct-drive traction motor developed directly for use on the axles of heavy-duty rail traction vehicles. For example... Figure 2As shown, to fully utilize the axial space of the axle and the clearance dimensions of the track, the traction motor adopts a slender design and is directly arranged along the axle: the stator assembly 2, with a welded frame and heat-shrinkable core winding structure, has a front end cover 3 and a rear end cover 1 mounted on each side near the frame stop. The rotor core 9 of the motor has silicon steel laminations arranged directly along the shaft 7, and the permanent magnet 8 is inserted into the V-groove of the rotor core 9 and sealed with glue. The motor stator assembly 2 is supported on the motor rotor by tapered roller bearings (tapered roller bearings) 5 at both ends, relying on the end covers at both ends. In order to reasonably control the preload or axial installation clearance of the double tapered roller bearings 5, the width dimensions of the two inner sealing rings (axial dimension matching) 6 need to be calculated in advance according to the relevant dimensional chain. When designing the air gap dimensions of the motor, electromagnetic performance and the flexible deformation of the shaft 7 during actual operation should be fully considered.

[0031] To create a labyrinth seal for the grease in the bearing chambers at both ends, and to ensure axial positioning and clamping of the tapered roller bearings 5 ​​at both ends, front outer sealing rings 4 and rear outer sealing rings 10, respectively, are arranged on the outer side of the bearings using interference fit. Finally, to achieve variable frequency drive control of the permanent magnet direct drive motor, a rotary transformer 11 is installed at the rear end.

[0032] like Figure 3 and 4 As shown, in order to make full use of the axial space of the axle and meet the vehicle clearance requirements for small wheel diameters, the electromagnetic load is reasonably balanced and selected to meet the high torque traction requirements of the self-propelled vehicle. The motor size is made as large as possible, and as many heat dissipation fins are arranged on the base and the end covers on both sides. The motor is naturally cooled by the airflow when the vehicle is moving forward, while eliminating the need for auxiliary equipment such as fans and air ducts and losses.

[0033] Thanks to the adoption of permanent magnet direct drive + fully enclosed natural cooling technology, the efficiency of the entire drive unit can reach over 90%.

[0034] When double tapered roller bearings (single-row tapered roller bearings) are installed back-to-back, preloading or axial clearance adjustment is required to ensure that the bearings can withstand the large axial and radial impact vibration loads during motor operation. The core principle is to control the difference between the outer and inner ring distances of the two bearings through relevant dimensional chain calculations, ultimately ensuring that the double tapered roller bearings operate within a reasonable axial clearance range. Figure 5 and Figure 6 These are the basic dimensions related to axial clearance. Table 1 serves as a calculation example for installation clearance. Figure 3 After inputting the relevant dimensions into Table 1, the clearance (calculated value) after assembly is controlled between 60μm and 100μm. At this time, the width value of the inner sealing ring is the matching dimension (37.15 dimension in the table).

[0035]

[0036] This invention is the first to use a double tapered roller bearing back-to-back mounting bearing arrangement with high axial impact vibration load tolerance in a traction motor.

[0037] This invention makes full use of the axial space of the axle, while meeting the vehicle clearance requirements for small wheel diameters. It rationally balances and selects electromagnetic loads to meet the high torque traction requirements of self-propelled vehicles. It maximizes the size of the motor and arranges as many heat dissipation fins as possible on the base and side end covers. It achieves fully enclosed natural cooling of the motor by utilizing the airflow when the vehicle is moving forward, while eliminating the need for auxiliary equipment such as fans and air ducts, as well as losses.

[0038] This invention employs double tapered roller bearings for back-to-back installation on a large-span simply supported beam on an axle. Through calculation and evaluation using the motor-related dimensional chain, the axial installation clearance of the double tapered roller bearings is ultimately controlled by the axial dimensions of the two inner sealing rings that are tightly attached to the inner ring end faces of the bearings, ensuring reliable and stable motor operation.

Claims

1. A high-axle-load direct-drive permanent magnet traction motor employing a double tapered roller bearing back-to-back mounting bearing structure, characterized in that, The traction motor is slender and arranged directly along the axle. The stator assembly (2) adopts a welded frame and a heat-shrinkable core winding structure. A front cover (3) and a rear cover (1) are installed on each side of the stator assembly (2) near the frame stop. A tapered roller bearing (5) is installed in each of the front cover (3) and the rear cover (1). The two tapered roller bearings (5) are installed back to back. The stator assembly (2) is supported on the motor rotor by the two tapered roller bearings (5) and the front and rear covers. The outer sides of the front and rear tapered roller bearings (5) are axially positioned and pressed by the front outer sealing ring (4) and the rear outer sealing ring (10) with interference fit. An inner sealing ring (6) is installed on the inner side of the front and rear tapered roller bearings (5) to ensure that the two tapered roller bearings (5) are in a reasonable axial clearance range during operation. By calculating the relevant dimensional chain, the difference between the outer ring spacing and the inner ring spacing of the two tapered roller bearings (5) is controlled to ensure that the two tapered roller bearings (5) are within a reasonable axial clearance range during operation; the calculation formula is as follows: ΔC1 = L1 + L2*2 + B1 + B2 - T1 - T2 - L3 ΔC2=(0.7*(D1-D11)+0.8*(d11-d1)) / tan(16.25 / 180*π)+(0.7*(D2-D21)+0.8*(d21-d2)) / tan(16.25 / 180*π) C = ΔC1 - ΔC2; ΔC1 is the clearance formed by the axial dimension chain, L1 is the horizontal distance between the shoulders of the two bearings, L2 is the width of the inner sealing ring, B1 is the width of the inner ring of the rear bearing, B2 is the width of the inner ring of the front bearing, T1 is the assembly height of the rear bearing, T2 is the assembly height of the front bearing, and L3 is the distance between the shoulders of the two bearings. ΔC2 is the axial clearance change caused by the installation; D1 is the outer diameter of the rear bearing; D11 is the inner diameter of the rear bearing housing; d11 is the diameter at the inner ring seat of the rear axle; d1 is the inner diameter of the rear bearing; D2 is the outer diameter of the front bearing; D21 is the inner diameter of the front bearing housing; d21 is the diameter at the inner ring seat of the front axle; d2 is the inner diameter of the front bearing; C is the clearance value after assembly; L3 = machine base length - front bearing housing positioning dimension - rear bearing housing positioning dimension.

2. The high-axle-load direct-drive permanent magnet traction motor with a double tapered roller bearing back-to-back mounting structure as described in claim 1, characterized in that, The base and the front and rear end covers form a fully enclosed structure; multiple heat dissipation ring ribs (12) are arranged on the outer surface of the base; multiple parallel heat dissipation ribs (13) are arranged on the outer end faces of the front and rear end covers.

3. The high-axle-load direct-drive permanent magnet traction motor with a double tapered roller bearing back-to-back mounting structure as described in claim 1, characterized in that, A rotary transformer (11) for frequency conversion drive control of permanent magnet traction motor is installed on the outside of the rear cover (1).

4. The high-axle-load direct-drive permanent magnet traction motor with a double tapered roller bearing back-to-back mounting structure as described in claim 2, characterized in that, A rotary transformer (11) for frequency conversion drive control of permanent magnet traction motor is installed on the outside of the rear cover (1).

5. The high-axle-load direct-drive permanent magnet traction motor with a double tapered roller bearing back-to-back mounting structure as described in claim 1, characterized in that, Labyrinth seals are used between the bearing chambers of the front and rear end covers and the tapered roller bearing (5).

6. The high-axle-load direct-drive permanent magnet traction motor with a double tapered roller bearing back-to-back mounting structure as described in claim 2, characterized in that, Labyrinth seals are used between the bearing chambers of the front and rear end covers and the tapered roller bearing (5).

7. The high-axle-load direct-drive permanent magnet traction motor with a double tapered roller bearing back-to-back mounting structure as described in claim 4, characterized in that, Labyrinth seals are used between the bearing chambers of the front and rear end covers and the tapered roller bearing (5).

8. The high-axle-load direct-drive permanent magnet traction motor with a double tapered roller bearing back-to-back mounting structure as described in claim 1, characterized in that, The rotor core (9) of the motor rotor is directly arranged with silicon steel laminations along the shaft (7), and the permanent magnet (8) is inserted into the V-groove of the rotor core (9) and sealed with glue.

9. The high-axle-load direct-drive permanent magnet traction motor with a double tapered roller bearing back-to-back mounting structure as described in claim 7, characterized in that, The rotor core (9) of the motor rotor is directly arranged with silicon steel laminations along the shaft (7), and the permanent magnet (8) is inserted into the V-groove of the rotor core (9) and sealed with glue.

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