Asynchronous traction motor

Abstract

The invention relates to a traction motor technology, in particular to an asynchronous traction motor to meet the technical requirements of a traction motor of a motor vehicle of a power centralized motor train unit with the speed of 200 kilometers per hour. The high-speed dynamic set traction motor is structurally characterized in that cast steel or ductile iron of a non-transmission end cover is improved to be high-strength cast aluminum alloy, so that the weight of the motor is reduced; the heat dissipation capability is improved by changing the arrangement of ventilation holes of the stator and the rotor of the motor, thereby improving the motor power; by changing the squirrel cage rotor structure, the high rotating speed performance of the motor is met. And the motor is excellent in performance and high in reliability, and the performance index meets the requirements of the power-concentrated motor train unit.

Description

Technical Field

[0001] The invention relates to traction motor technology, in particular to an asynchronous traction motor. Background Art

[0002] With the development of the domestic railway network, both the high-speed railway network and the conventional railway network have become mature. Due to the limitations of the railway network system, there is a problem that high-speed and conventional railway trains cannot be connected, resulting in a large number of high-speed railway "detours". To solve this problem, the China Railway Group plans to develop a 200 km / h grade power-concentrated EMU (hereinafter referred to as EMU), which has the characteristics of 17 tons axle weight and high speed, and can run on passenger dedicated lines and conventional railways. It has a very obvious passenger transportation improvement capacity for areas that can only be reached by conventional railways but cannot be reached by high-speed railways, and can also solve the problem of high-speed railway detours in some areas.

[0003] The current parameters of traction motors for domestic high-speed electric passenger locomotives are as follows: .

[0004] Compared with the locomotive traction motors currently in operation, the traction motors of 200 km / h-class centralized power EMU power vehicles need to have the following characteristics: (1) The maximum motor speed is 3817 r / min ， The locomotive's constant power speed range is 110-200 km / h, and its maximum operating speed is 200 km / h, which is currently the highest operating speed of a centralized power locomotive in China. (2) The motor is lightweight in design, weighing 1750 kg, meeting the requirement for an axle weight of 17 t. (3) The motor uses a pinion hollow shaft transmission to drive the locomotive axle. The new transmission device has stricter requirements on the axial length of the motor.

[0005] In summary, there is a great need for a traction motor that can meet the above conditions and is suitable for a 200 km / h-class power concentrated EMU power vehicle. Summary of the invention

[0006] The present invention provides an asynchronous traction motor suitable for high-power and high-speed centralized power EMUs, which is used to realize the high-speed railization of locomotives. As a core component of the traction electric transmission system, the traction motor plays a core role in speeding up and providing traction, and meets the traction motor standards mentioned in the background technology.

[0007] The present invention is implemented by adopting the following technical scheme: an asynchronous traction motor, including a stator, a rotor, a base, stator pressure rings at both ends, rotor pressure plates at both ends, end covers at both ends and a double-end bearing support structure that supports the rotor, the protruding end of the motor shaft is the transmission end; the stator pressure ring at the non-transmission end is provided with an air inlet, the end cover at the transmission end is provided with an air outlet, the stator iron core, the stator pressure ring at the transmission end and the stator pressure ring at the non-transmission end are all provided with the same number of axially oriented stator ventilation holes in the circumferential direction to form a stator axial wind path; the rotor iron core, the rotor pressure plate at the transmission end and the rotor pressure plate at the non-transmission end are all provided with the same number of rotor ventilation holes in the circumferential direction to form a rotor axial wind path.

[0008] The present invention improves the heat dissipation capacity by changing the arrangement of the ventilation holes of the stator and rotor of the motor, thereby improving the power of the motor.

[0009] Furthermore, the portion of the stator winding extending out of the stator slot and close to the end of the stator slot is potted and wrapped in the potting material.

[0010] Furthermore, the motor rotor adopts an end ring plus a guard ring structure, the end ring and the guide bar of the rotor cage are welded by medium frequency induction welding, and the end ring welding groove and the guide bar are interference fit; after the end ring is welded, the outer circle and end surface are processed, and the outer side is heat-shrink-fitted with a guard ring.

[0011] Furthermore, three guide bars are grouped together, and the extended guide bars are bent; the guide bars are fixed in the grooves by applying external radial force to the guide bars so that the tops of the guide bars are plastically deformed.

[0012] Furthermore, among the three groups of guide bars, the guide bars on both sides are bent toward the middle guide bar at a certain angle, and then the end rings are installed.

[0013] Furthermore, the distance between the ends of the conductor bars on both sides and the ends of the middle conductor bars is 10 mm, and the bending angle is 8.7 degrees; the bending position is 1 mm between the conductor bars and the rotor core; and the aspect ratio of the end ring is 2:1.

[0014] The present invention solves the vibration failure of high-speed rotating machinery and improves the ability to resist centrifugal force by optimizing the squirrel cage structure, thereby achieving high-speed working conditions and increasing the life of the rotor.

[0015] Furthermore, the non-drive end cover is made of high-strength aluminum alloy, and several reinforcing ribs are added inside and outside the end cover to achieve a lightweight design of the end cover while meeting the strength requirements. Through the optimal selection of component materials, the lightweight design of the entire machine is achieved while ensuring the electromagnetic performance and structural reliability of the motor. The non-drive end cover is made of high-strength cast aluminum alloy, and the weight of the motor is reduced by 70kg with the same performance.

[0016] The internal structure of the motor is compact, and compared with other traction motors with shaft extensions at the drive end of the same gauge, the axial length of the motor is shortened by 400mm.

[0017] The rotor speed of the traction motor is high, which is the highest among the current locomotive traction motors with online rotor linear speed. The high-speed motor places higher requirements on the rotor system. The present invention solves the vibration failure of the rotating machinery and resists the centrifugal force by optimizing the squirrel cage structure, thereby achieving high-speed working conditions and increasing the rotor life.

[0018] Beneficial effects of the invention: The traction motor described in the invention can be used in 200km / h high-speed centralized power EMUs, filling the gap in high-speed centralized power EMUs. The motor has reliable performance, high maintainability, and long service life. Various performance indicators meet the operating requirements of the power vehicle. The successful development of this motor improves the passenger capacity of areas that high-speed rails cannot reach but can only be reached by conventional rails, solves the problem of high-speed rail detours in some areas, and drives the improvement of rail transit-related technical industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the cross-sectional structure of the motor according to the present invention.

[0020] Figure 2 A three-dimensional schematic diagram of the motor of the present invention from a first perspective (transmission end side).

[0021] Figure 3 A three-dimensional schematic diagram of the motor of the present invention from a second viewing angle (non-transmission end side).

[0022] Figure 4 Schematic diagram of the cooling path of the motor according to the present invention.

[0023] Figure 5 Schematic diagram of the cross-section of the motor stator and rotor core.

[0024] Figure 6 Schematic diagram of rotor bar bending.

[0025] Figure 7 Enlarged schematic diagram of rotor bar bending.

[0026] Figure 8 Schematic diagram of rotor components.

[0027] 1-shaft, 2-non-drive end bearing, 3-bearing seat, 4-rotor core, 5-stator winding, 6-non-drive end cover, 7-non-drive end stator pressure ring, 8-stator core, 9-junction box, 10-drive end stator pressure ring, 11-drive end cover, 12-drive end bearing, 13-stator ventilation hole, 14-rotor ventilation hole, 15-rotor pressure plate, 16-guide bar, 17-guard ring, 18-end ring. DETAILED DESCRIPTION

[0028] The present invention is a traction motor suitable for high-speed EMUs, and its structural features are as follows: the non-drive end cover is upgraded from cast steel or ductile iron to high-strength cast aluminum alloy to reduce the weight of the motor; the heat dissipation capacity is improved by changing the arrangement of the ventilation holes of the motor stator and rotor, thereby increasing the motor power; and the high-speed performance of the motor is met by changing the squirrel cage rotor structure. The motor has excellent performance and high reliability at constant power speed, and the performance indicators meet the requirements of power-concentrated EMUs. The present invention is further described below in conjunction with the accompanying drawings.

[0029] like Figure 1 As shown, the traction motor includes a stator and a rotor, a base, end covers at both ends and a double-end bearing support structure that supports the rotor. The protruding end of the motor shaft is the transmission end. The motor is cooled by a fan on the locomotive. The cooling air enters from the air inlet above the non-transmission end, passes through the vents set on the stator and rotor, and is discharged from the vents on the transmission end cover.

[0030] The double-bearing support structure means that the non-drive end of the rotor is supported by the non-drive end cover and the non-drive end bearing unit, and the drive end of the rotor is supported by the drive end cover and the drive end bearing unit. Therefore, the motor end cover must have high strength and strong rigidity to resist external vibration and impact during the operation of the motor. At the same time, in order to reduce the weight of the motor, the non-drive end is made of high-strength aluminum alloy material, and the mechanical properties of this material are consistent with those of alloy steel.

[0031] In order to meet the high-speed operation of the rotor, the motor rotor is set to a squirrel cage structure with a guard ring. While ensuring the cross-sectional area of ​​the end ring, the aspect ratio of the end ring is increased (2:1), and the length of the conductor bar extending out of the core is shortened. Through the optimized design of the end ring and conductor bar structure, the centrifugal force on the motor during operation is reduced and the natural frequency of the rotor is increased.

[0032] like Figure 4 As shown, cooling air enters the motor from the inlet above the non-drive end of the motor. As the motor rotor rotates inside the motor, the core heats up the most during the operation of the motor. The internal contours of the end covers at both ends are designed as guide air paths to guide the cooling air into the core. The stator core, the stator pressure ring at the drive end, and the stator pressure ring at the non-drive end are evenly distributed with the same number of axial ventilation holes to form a stator air path. The rotor core, the rotor pressure plate at the drive end, and the rotor pressure plate at the non-drive end are evenly distributed with the same number of circular ventilation holes in the circumferential direction to form a rotor axial air path, as shown by the arrows.

[0033] At the same time, because the suspended part of the rotor cage will form a radial pressure difference, that is, the part of the rotor bars extending out of the two ends of the rotor slot is equivalent to a centrifugal fan, which will cause certain damage to the insulation of the corresponding motor stator part. Over time, it will cause the insulation material of the stator winding to be layered and peeled off until the coil conductor is exposed, causing the motor to ground fault. This motor pots the stator winding coil at the part of the stator winding that extends out of the stator slot and close to the end of the stator slot, wrapping it in the potting material, thereby extending the service life of the stator winding.

[0034] like Figure 5 As shown, ventilation holes of matching size and number are arranged on the stator and rotor cores of the motor without affecting the magnetic circuit and the magnetic density of the yoke, so as to ensure that the heat dissipation surface area and ventilation area of ​​the air duct are optimal, the air volume distribution of the stator and rotor is reasonable, and the internal wind resistance of the motor is minimized within a limited space.

[0035] The non-drive end cover is fixed on the non-drive end stator pressure ring to fix and support the motor rotor. The bearing seat is installed in the end cover with an overfit, the outer ring of the bearing is pressed into the bearing seat, and the inner ring of the bearing is shrink-fitted on the shaft and positioned by the shaft step; to ensure structural reliability, the end cover of the locomotive traction motor mostly uses a cast steel structure, and its weight accounts for a large proportion of the total weight of the motor. This motor has strict weight requirements. The present invention adopts the following technical solutions to achieve the lightweight design of the motor: the non-drive end cover is made of high-strength aluminum alloy material, and a number of reinforcing ribs are added inside and outside the end cover to achieve the lightweight design of the end cover while meeting the structural strength.

[0036] like Figure 8 As shown in the figure, the motor rotor adopts the structure of end ring plus guard ring. The end ring and guide bar of the rotor cage are welded by medium frequency induction. The end ring welding groove and the guide bar are selected with appropriate interference size. After the end ring is welded, the outer circle and end surface are processed, and the outer side is heat-covered with guard ring to ensure that the guide bar and end ring will not be greatly deformed during high-temperature welding and high-speed rotation of the rotor. The following measures are adopted to improve the natural frequency of the cage structure: like Figure 6 , 7 As shown in the figure, (1) the length of the conductor bar extending out of the core is shortened; (2) the extended conductor bars are bent as a group of three conductor bars; (3) the conductor bars are fixed in the slots by applying an external radial force to the conductor bars to cause plastic deformation of the top of the conductor bars (i.e., "tensioning"), thereby ensuring the stability of the rotor ends. The entire axial length of the rotor core is tensioned, and to facilitate the bending of the conductor bars, no tension is applied 10 mm from both ends of the core.

Claims

1. An asynchronous traction motor, comprising a stator, a rotor, a base, stator pressure rings at both ends, rotor pressure plates at both ends, end covers at both ends, and a double-end bearing support structure for supporting the rotor, wherein the protruding end of the motor shaft is the transmission end; characterized in that: The stator pressure ring at the non-drive end is provided with an air inlet, the end cover at the drive end is provided with an air outlet, the stator core, the stator pressure ring at the drive end and the stator pressure ring at the non-drive end are all provided with the same number of axially oriented stator ventilation holes in the circumferential direction to form a stator axial wind path; the rotor core, the rotor pressure plate at the drive end and the rotor pressure plate at the non-drive end are all provided with the same number of rotor ventilation holes in the circumferential direction to form a rotor axial wind path.

2. An asynchronous traction motor according to claim 1, characterized in that: The portion of the stator winding extending out of the stator slot and close to the end of the stator slot is potted and wrapped in the potting material.

3. An asynchronous traction motor according to claim 1 or 2, characterized in that: The motor rotor adopts the structure of end ring plus guard ring. The end ring and guide bar of the rotor cage are welded by medium frequency induction welding. The welding groove of the end ring and the guide bar are interference fit. After the end ring is welded, the outer circle and end face are processed, and the outer side is heat-shrink-fitted with the guard ring.

4. An asynchronous traction motor according to claim 3, characterized in that; Three guide bars form a group, and the protruding guide bars are bent; the guide bars are fixed in the grooves by applying external radial force to the guide bars to cause plastic deformation at the top of the guide bars.

5. An asynchronous traction motor according to claim 4, characterized in that: Among the three groups of guide bars, the guide bars on both sides are bent at a certain angle toward the middle guide bar, and then the end rings are installed.

6. An asynchronous traction motor according to claim 5, characterized in that: The distance between the ends of the two side bars and the middle bar is 10 mm, and the bending angle is 8.7 degrees; The bending position is where the guide bar is 1mm away from the rotor core; the aspect ratio of the end ring is 2:

1.

7. An asynchronous traction motor according to claim 1 or 2, characterized in that: The non-transmission end cover is made of high-strength aluminum alloy material, and several reinforcing ribs are added inside and outside the end cover.

8. An asynchronous traction motor as claimed in claim 3, characterized in that: The non-transmission end cover is made of high-strength aluminum alloy material, and a number of reinforcing ribs are added inside and outside the end cover.

9. An asynchronous traction motor according to claim 6, characterized in that: The non-transmission end cover is made of high-strength aluminum alloy material, and a number of reinforcing ribs are added inside and outside the end cover.

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