Large-axle-load direct-drive permanent magnet traction motor adopting double-TRB back-to-back mounting bearing structure

Abstract

The invention relates to a permanent magnet traction motor, in particular to a large-axle-load direct-drive permanent magnet traction motor adopting a double-TRB back-to-back mounting bearing structure, and the motor is used as a driving unit to be applied to a self-walking track running vehicle for metallurgy, mining and energy exploitation. The traction motor is thin and long and is directly arranged along an axle, a stator assembly adopts a welding machine base and hot jacket iron core winding structure, and a front end cover and a rear end cover are assembled on the two sides of the stator assembly and close to machine base spigots respectively. The front end cover and the rear end cover are each internally provided with a tapered roller bearing, and the two tapered roller bearings are installed in a back-to-back mode. The stator assembly is supported on the motor rotor through the two tapered roller bearings by relying on the front end cover and the rear end cover; the outer sides of the front tapered roller bearing and the rear tapered roller bearing are axially positioned and compressed through a front outer sealing ring and a rear outer sealing ring which are in interference fit respectively; and the inner sides of the front tapered roller bearing and the rear tapered roller bearing are respectively provided with an inner sealing ring for ensuring that the two tapered roller bearings are in a reasonable axial clearance range during operation.

Description

TECHNICAL FIELD

[0001] The present application relates to a permanent magnet traction motor, in particular, the motor is used as a driving unit in a large axle load molten steel, ore, powder material and other self-propelled track running vehicles in metallurgical, mining and energy exploitation enterprises, in particular, a large axle load direct drive permanent magnet traction motor with double TRB back-to-back bearing structure. BACKGROUND

[0002] Compared with the locomotive running on the national railway line, the transfer vehicle bogie of the self-provided transfer vehicle of the factory and mine enterprise has the characteristics of short wheelbase, small wheel diameter (φ820), large axle weight (already up to 43t axle weight), thick axle (wheel pie position φ275, maximum outer diameter φ306), large traction torque (starting torque up to 12000Nm, rated torque up to 7200Nm), and most of them use diesel locomotive traction to transfer materials with the vehicle. In recent years, with the green and environmental transformation of major enterprises, old diesel locomotives are gradually eliminated, and battery-powered unmanned self-propelled power vehicles are used.

[0003] The prior art scheme one is shown in Figure 1 In order to provide traction power for the wheel set of the self-propelled vehicle, the rotating shaft of the traction motor is arranged in parallel with the axle of the wheel set, the traction motor outputs torque through the rotating shaft, a driving pinion is installed at the end of the rotating shaft, and the traction power is transmitted to the axle through the meshing of the driving pinion and the driven gear. The traction motor is installed and connected through bolts by rolling bearings and a shaft box that surrounds the axle.

[0004] The disadvantages of the prior art one are: a, the traction motor is arranged in parallel with the axle, which occupies more space of the wheelbase of the vehicle, and is not conducive to the installation and arrangement of other accessories such as braking and wiring.

[0005] b, a complete set of rolling bearings and shaft box bodies need to be added on the axle, the mechanical structure is more complex, and the failure rate is high.

[0006] c, there is gear transmission, which will cause transmission loss and low efficiency of the driving device.

[0007] The prior art scheme two is to use direct drive transmission technology on the basis of Figure 1 The hollow shaft sleeve is sleeved on the axle, and six-link transmission mechanisms are installed at both ends of the hollow shaft sleeve. The traction motor also uses a hollow shaft instead of a solid shaft, which is arranged concentrically with the axle, and the traction motor rotor core is arranged on the hollow shaft. The end surface of the traction motor hollow shaft is provided with an end surface gear, which is meshed with the end surface gear arranged on the six-link transmission mechanism at one end of the hollow shaft sleeve, and finally realizes the following torque transmission path: Traction motor hollow shaft→one end six-link transmission mechanism→hollow shaft sleeve→the other end six-link transmission mechanism→the other end wheel to generate traction power.

[0008] The disadvantages of the prior art two are: a, traction motor is arranged concentrically with the axle, which occupies less space of the vehicle wheelbase, but due to the adoption of two-layer hollow shaft and hollow shaft sleeve, the radial space is relatively large, and for the small wheel diameter self-propelled vehicle with large axle load, the outer diameter of the traction motor is too large to exceed the limit regulation.

[0009] b, a complete set of hollow shaft sleeve and six-link transmission mechanism need to be added on the axle, and the structure is relatively complex.

[0010] c, the structure has relatively weak bearing capacity for line impact vibration load, and is suitable for occasions with good line working conditions. SUMMARY

[0011] The present application is to solve the technical problems of limited space size under the axle of the current factory and mine enterprise self-propelled vehicle bogie, poor line impact vibration working condition and high heat dissipation requirement, and provides a large axle load direct drive permanent magnet traction motor adopting double TRB back-to-back bearing structure.

[0012] The present application is implemented by the following technical scheme: a large axle load direct drive permanent magnet traction motor adopting double TRB back-to-back bearing structure, the traction motor is in an elongated type and is arranged directly along the axle, the stator assembly adopts a welded base + hot sleeve core winding structure, and each of the two sides of the stator assembly is assembled with a front end cover and a rear end cover through the base stop; each of the front end cover and the rear end cover is internally mounted with a tapered roller bearing, and the two tapered roller bearings are installed back-to-back; the stator assembly is supported on the motor rotor through the two tapered roller bearings and relying on the front and rear end covers; the outer sides of the two tapered roller bearings are respectively realized axial positioning and compression through the front and rear outer sealing rings assembled by winning; the inner sides of the two tapered roller bearings are respectively mounted with an inner sealing ring for ensuring that the two tapered roller bearings are within a reasonable axial clearance range during operation.

[0013] Further, through related size chain accounting, 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 are within a reasonable axial clearance range during operation; the calculation formula is as follows: Delta C1=L1+L2*2+B1+B2-T1-T2-L3 Delta C2=(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=Delta C1-Delta C2; DeltaC1 is the axial dimension chain formed gap, L1 is the two bearing shoulder horizontal distance, L2 is the inner sealing ring width, B1 is the rear bearing inner ring width, B2 is the front bearing inner ring width, T1 is the rear bearing assembly height, T2 is the front bearing assembly height, L3 is the distance between the two bearing seats shoulder; DeltaC2 is the axial gap variation formed by matching installation, D1 is the rear bearing outer diameter, D11 is the rear bearing seat inner hole diameter, d11 is the diameter at the rear axle inner ring seat, d1 is the rear bearing inner diameter, D2 is the front bearing outer diameter, D21 is the front bearing seat inner hole diameter, d21 is the diameter at the front axle inner ring seat, d2 is the front bearing inner diameter; C is the gap value after assembly; L3 = machine length - front bearing seat positioning size - rear bearing seat positioning size.

[0014] Further, the machine seat and the front and rear end covers constitute a fully enclosed structure; the outer surface of the machine seat is provided with multiple heat dissipation ring ribs; the outer end face of the front and rear end covers is provided with multiple parallel heat dissipation ribs.

[0015] Further, a rotary transformer for controlling the variable frequency drive of the permanent magnet traction motor is installed on the outer side of the rear end cover.

[0016] Further, the bearing chamber of the front and rear end covers and the tapered roller bearing adopt a labyrinth seal.

[0017] Further, the rotor core of the motor rotor is directly arranged with silicon steel laminations along the shaft, and the permanent magnet is inserted into the V-shaped slot of the rotor core and is sealed by pouring glue.

[0018] In order to meet the space size of the self-propelled vehicle bogie under the axle of the factory and mine enterprise, the application designs an elongated permanent magnet toothless box direct drive traction motor.

[0019] According to the characteristics of large traction tonnage (for example: the weight of open steel water tank can reach 240t), low speed (within 20km / h), and hour operation of the track self-propelled equipment, on the basis of the foregoing elongated overall scheme, the electromagnetic compliance of the motor is reasonably selected, and the fully enclosed natural cooling technology is considered.

[0020] Considering that the track line conditions of most factories and mines are poor, the traction tonnage is large, it belongs to low speed heavy load, and the line impact vibration working condition is poor, etc., the bearing selection and bearing performance calculation need to be focused on. Finally, the double tapered roller bearing (TRB) back-to-back (small diameter end of the tapered roller bearing adjacent) installation structure is selected, which effectively improves the axial bearing 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. It also has strong axial load bearing capacity of double TRB bearings and the efficiency of the drive unit 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 dual TRB bearing configuration example of this invention.

[0027] Figure 6 The second illustration of the relevant dimensions in the calculation example of the dual TRB bearing configuration 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, in order to make full use of the axial space of the axle and the limit size of the line, the traction motor is arranged in an elongated manner directly along the axle: the stator assembly 2 is equipped with a front end cover 3 and a rear end cover 1 on each side of the seat stop. The rotor core 9 of the motor is arranged directly along the axle 7 with silicon steel laminations, and the permanent magnet 8 is inserted into the V-shaped slot of the rotor core 9 and sealed with glue. The motor stator assembly 2 is supported on the motor rotor through two end tapered roller bearings (TRB) 5 relying on the two end covers. In order to reasonably control the pre-tightening or axial installation clearance of the double TRB bearing 5, the width dimension of the two inner sealing rings (axial dimension matching) 6 needs to be determined in advance according to the relevant size chain calculation. When designing the air gap size of the motor, the electromagnetic performance and the flexible deformation of the axle 7 in actual operation should be fully considered.

[0031] In order to form a labyrinth seal for the lubricating grease in the two end bearing chambers, and at the same time to well position and press the two end tapered roller bearings 5, the front outer sealing ring 4 and the rear outer sealing ring 10 are arranged on the outer side of the bearing by over-wining assembly. Finally, in order to realize the variable frequency drive control of the permanent magnet direct drive motor, a rotary transformer 11 is arranged at the rear end.

[0032] As shown in Figure 3 and 4 , in order to make full use of the axial space of the axle, while meeting the vehicle limit requirement when the wheel diameter is small, reasonably balancing the electromagnetic load, meeting the large torque traction demand of the self-propelled vehicle, making the motor size as large as possible, and arranging as many heat dissipation ribs as possible on the seat and the two side end covers, the motor is naturally cooled by the running wind when the vehicle moves forward, and the auxiliary equipment such as fan and air duct and the loss are saved.

[0033] Due to the adoption of permanent magnet direct drive + fully enclosed natural cooling technology, the efficiency of the whole drive unit can reach more than 90%.

[0034] When the double TRB (single row tapered roller bearing) bearings are installed back to back, in order to ensure that the bearings can bear the large axial and radial impact vibration load during the operation of the motor, the paired bearings need to be pre-tightened or the axial installation clearance is adjusted. The core principle is to control the difference between the outer ring spacing and the inner ring spacing of the two bearings through relevant size chain calculation, and finally ensure that the double TRB bearings are within a reasonable axial clearance range during operation. Figure 5 and Figure 6 are basic dimensions related to the axial clearance, and Table 1 is taken as an installation clearance matching example. After inputting the related dimensions in Figure 3 into Table 1, the assembled clearance (calculated value) is controlled within 60μm-100μm, and at this time the width value of the inner sealing ring is the matching dimension (37.15 dimension in the table).

[0035] Table 1 Double TRB bearing pre-tightening and axial installation clearance matching calculation table .

[0036] The application firstly adopts the double TRB back-to-back mounting bearing arrangement structure with high axial impact vibration load resistance on the traction motor.

[0037] The application fully utilizes the axial space of the axle, meets the vehicle limit requirement when the wheel diameter is small, reasonably balances the electromagnetic load, meets the large torque traction demand of the self-propelled vehicle, makes the motor size as large as possible, and arranges as many heat dissipation ribs as possible on the motor base and both side end covers, realizes the full-closed natural cooling of the motor by means of the walking wind when the vehicle advances, and saves the auxiliary equipment and loss such as the fan and the air duct.

[0038] When the double TRB bearing is mounted on the axle in the large-span simply supported beam back-to-back mode, the axial installation clearance of the double TRB bearing is controlled through the axial size of the two inner sealing rings close to the end face of the inner ring of the bearing by the motor association size chain calculation and evaluation, so that the motor operation is reliable and stable.

Claims

1. A large axle load direct drive permanent magnet traction motor with double TRB back-to-back mounted bearing structure, characterized in that, The traction motor is slender and arranged directly along the axle. The stator assembly (2) adopts a welded frame + hot-fitted iron 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) respectively using over-fitting assembly. 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.

2. The large-tread straight-drive permanent magnet traction motor with dual-TRB back-to-back mounted bearing structure according to claim 1, characterized in that, 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.

3. The large-tread straight-drive permanent magnet traction motor with double TRB back-to-back mounted bearing structure according to claim 1 or 2, 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.

4. The large-tread straight-drive permanent magnet traction motor with dual TRB back-to-back mounted bearing structure according to claim 1 or 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 large-tread straight-drive permanent magnet traction motor with dual-TRB back-to-back mounted bearing structure according to claim 3, 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).

6. The large-tread straight-drive permanent magnet traction motor with dual TRB back-to-back mounted bearing structure according to claim 1 or 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 large-tread straight-drive permanent magnet traction motor with dual TRB back-to-back mounted bearing structure according to claim 3, 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 large-tread straight-drive permanent magnet traction motor with dual TRB back-to-back mounted bearing structure according to claim 5, characterized in that, Labyrinth seals are used between the bearing chambers of the front and rear end covers and the tapered roller bearing (5).

9. The large-tread straight-drive permanent magnet traction motor with dual TRB back-to-back mounted bearing structure according to claim 1 or 2, 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.

10. The large-tread straight-drive permanent magnet traction motor with dual TRB back-to-back mounted bearing structure according to claim 8, characterized in that, The rotor iron core (9) of the motor rotor is arranged with silicon steel laminations directly along the shaft (7), and the permanent magnet (8) is inserted into the V-shaped slot of the rotor iron core (9) and is sealed by pouring glue.

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