Motor shaft structure and vehicle

Abstract

This invention discloses a motor shaft structure and a vehicle, comprising a motor shaft with a rotor core mounted on it. A composite material layer is disposed on the outer circumferential surface of the shaft section that mates with the rotor core. When the motor shaft is not rotating, the composite material layer and the rotor core have a clearance fit; when the motor shaft rotates, they have an interference fit. This invention utilizes the fundamental principle that different materials have different thermal expansion at the same temperature, combined with existing processing methods and techniques, to coat the exterior of the original material motor shaft with a composite material, causing the clearance between the rotor core and the motor shaft to change with temperature.

Description

Technical Field

[0001] This invention belongs to the field of new energy vehicle technology, and specifically discloses a motor shaft structure and a vehicle. Background Technology

[0002] In electric vehicle development, the fit between the inner diameter of the rotor core and the outer diameter of the motor shaft in the motor rotor assembly varies, each with its own advantages and disadvantages. For example, an interference fit between the motor shaft and the rotor core is beneficial for NVH performance during operation. However, this requires a specialized press during production, and because the core is made of multiple layers of laminations, manufacturing defects such as lamination warping are easily generated during the pressing process. Conversely, a clearance fit between the motor shaft and the rotor core will cause slight rotation of the rotor core at high speeds, leading to poor rotor dynamic balance and deterioration of NVH during motor operation. Summary of the Invention

[0003] To address the technical problems existing in the prior art, the present invention provides a motor shaft structure and vehicle, which utilizes the basic principle that different materials have different thermal expansion at the same temperature, combined with existing processing methods and processes, to coat the exterior of the original material motor shaft with a composite material, so that the gap between the rotor core and the motor shaft changes with temperature.

[0004] This invention discloses a motor shaft structure, which includes a motor shaft and a rotor core disposed on the motor shaft. A composite material layer is disposed on the outer circumferential surface of the shaft section of the motor shaft that mates with the rotor core. When the motor shaft is not rotating, the composite material layer and the rotor core are in clearance fit. When the motor shaft is rotating, the composite material layer and the rotor core are in interference fit.

[0005] In a preferred embodiment of the present invention, the material formulation of the composite material layer is as follows: PA66 plastic as the base material, 1% compatibilizer maleic anhydride grafted polyphenylene ether is added, 10% glass fiber is added, and 2.5% tetrafluoroethylene is added.

[0006] In a preferred embodiment of the present invention, the thickness δ of the composite material layer is 4mm-6mm.

[0007] In a preferred embodiment of the present invention, the thermal expansion of the composite material layer is Δδ: Δδ=(t1-t2)×δ×α; where t1 is the termination temperature of the motor shaft, t2 is the starting temperature of the motor shaft, δ is the thickness of the composite material layer, and α is the coefficient of thermal expansion 9.5×10 -5 m / K.

[0008] In a preferred embodiment of the present invention, the thermal expansion of the composite material layer is Δδ, which is 0.057-0.0855 mm.

[0009] In a preferred embodiment of the present invention, the gap between the motor shaft and the rotor core is 0.01mm-0.05mm.

[0010] In a preferred embodiment of the present invention, two core pressure plates are provided on the motor shaft and spaced apart along its axial direction, and a rotor core is provided between the core pressure plates.

[0011] In a preferred embodiment of the present invention, a flat key is provided on the motor shaft, and the flat key is provided on the shaft section that mates with the rotor core.

[0012] In a preferred embodiment of the present invention, the iron core pressure plate is fixedly connected to the motor shaft by a steel ring for axial positioning.

[0013] The present invention also discloses a vehicle that includes a generator, the generator including a motor shaft structure.

[0014] The beneficial effects of this invention are as follows: The invention has a simple structure, allowing for a clearance fit between the motor shaft surface and the iron core in a cold state, which is beneficial for rotor assembly and reduces rotor core scrap rate. After the motor starts running, as the temperature rises, the fit between the iron core and the motor shaft changes to an interference fit, reducing slight cross-movement of the iron core during operation. By using this invention, not only can manufacturing defects such as lamination warping easily occur during press-fitting caused by an interference fit between the motor shaft and the rotor iron core, but it can also avoid the NVH deterioration during motor operation caused by a clearance fit between the motor shaft and the rotor iron core.

[0015] Furthermore, this invention uses PA66 plastic as the base material and adds 1% maleic anhydride-grafted polyphenylene ether as a compatibilizer for compatibilization and toughening modification, thereby improving the toughness of PA66 material. The addition of 10% glass fiber increases the surface hardness of the parts, and the addition of 2.5% tetrafluoroethylene improves the surface wear resistance of the material.

[0016] Furthermore, the composite material of this invention is integrated with the motor shaft, giving the motor shaft surface wear-resistant and thermally expandable properties, while the strength of the motor shaft itself is not affected. Attached Figure Description

[0017] Figure 1 This is an exploded view of a motor shaft structure according to the present invention;

[0018] Figure 2 This is a schematic diagram of a motor shaft structure according to the present invention;

[0019] Figure 3 This is a schematic diagram illustrating the improvement of motor NVH performance using a motor shaft structure according to the present invention;

[0020] In the diagram: 1-Shift motor; 2-First-stage reduction gear; 3-Second-stage reduction gear; 4-Shift drum gear; 5-Shift drum; 6-Shift fork assembly; 7-Synchronizer / dog clutch; 5.1-First annular groove; 5.2-Second annular groove; 6.1-Shift fork shaft; 6.2-Shift fork; a-First slider; b-Second slider; 6.3-Connecting rod of the first slider; 6.4-Connecting rod of the second slider. Detailed Implementation

[0021] The technical solutions (including preferred technical solutions) of the present invention will be further described in detail below with reference to the accompanying drawings and by way of listing some optional embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] like Figure 1-2 As shown, the present invention discloses a motor shaft structure, which includes a motor shaft 1, a rotor core 5 disposed on the motor shaft 1, and a composite material layer disposed on the outer circumferential surface of the shaft section of the motor shaft 1 that mates with the rotor core 5. When the motor shaft 1 is not rotating, the composite material layer and the rotor core 5 are in clearance fit, and when the motor shaft 1 is rotating, the composite material layer and the rotor core 5 are in interference fit.

[0023] In a preferred embodiment of the present invention, the material formulation of the composite material layer is as follows: PA66 plastic as the base material, 1% compatibilizer maleic anhydride-grafted polyphenylene ether is added, 10% glass fiber is added, and 2.5% tetrafluoroethylene is added.

[0024] In a preferred embodiment of the present invention, the thickness δ of the composite material layer is 4mm-6mm.

[0025] In a preferred embodiment of the present invention, the thermal expansion of the composite material layer is Δδ: Δδ=(t1-t2)×δ×α; where t1 is the termination temperature of the motor shaft, t2 is the starting temperature of the motor shaft, δ is the thickness of the composite material layer, and α is the coefficient of thermal expansion 9.5×10 -5 m / K, where the initial temperature of the motor shaft refers to the temperature of the outer circumference of the motor shaft when the motor shaft 1 is not rotating and the composite material layer and the rotor core 5 are in clearance fit; the final temperature of the motor shaft refers to the temperature of the outer circumference of the motor shaft when the motor shaft 1 is rotating and the composite material layer and the rotor core 5 are in interference fit.

[0026] In a preferred embodiment of the present invention, the thermal expansion of the composite material layer is Δδ, which is 0.057-0.0855 mm.

[0027] In a preferred embodiment of the present invention, the gap between the motor shaft 1 and the rotor core 5 is 0.01mm-0.05mm.

[0028] In a preferred embodiment of the present invention, two iron core pressure plates 2 are arranged axially spaced on the motor shaft 1, and a rotor iron core 5 is arranged between the iron core pressure plates 2.

[0029] In a preferred embodiment of the present invention, a flat key 3 is provided on the motor shaft 1, and the flat key 3 is provided on the shaft segment that cooperates with the rotor core 5.

[0030] In a preferred embodiment of the present invention, the iron core pressure plate 2 is fixedly connected to the motor shaft 1 by the steel ring 6 for axial positioning.

[0031] The present invention also discloses a vehicle that includes a generator, the generator including a motor shaft structure.

[0032] This invention, based on existing motor shaft designs, adds a layer of composite material to the mating surfaces of the motor shaft and the iron core while ensuring shaft strength. This allows the motor shaft to maintain a clearance fit between the iron core and the motor shaft in a cold state, meeting initial production and assembly requirements. When the motor is running, the composite material expands due to its own heat generation, and the expansion of the composite material on the motor shaft exceeds that of the iron core. This changes the fit between the iron core and the motor shaft to an interference fit. This optimizes the dynamic balance of the rotor assembly under motor operating conditions and improves the motor's NVH performance. (Line A represents the original motor, line B represents the test results after using the new motor shaft, and line C represents the acceptance standard.)

[0033] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are not intended to limit the invention. Any modifications, combinations, substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A motor shaft structure, comprising a motor shaft (1), wherein a rotor core (5) is disposed on the motor shaft (1), characterized in that: A composite material layer is provided on the outer circumferential surface of the shaft section of the motor shaft (1) that mates with the rotor core (5). When the motor shaft (1) is not rotating, the composite material layer and the rotor core (5) are in clearance fit. When the motor shaft (1) is rotating, the composite material layer and the rotor core (5) are in interference fit. The material formula of the composite material layer is: PA66 plastic as the base material, 1% maleic anhydride grafted polyphenylene ether, 10% glass fiber, and 2.5% tetrafluoroethylene.

2. The motor shaft structure according to claim 1, characterized in that: The thickness δ of the composite material layer is 4mm-6mm.

3. The motor shaft structure according to claim 1, characterized in that: The thermal expansion of the composite material layer is Δδ: Δδ = (t1 - t2) δ α； in, t1 is the final temperature of the motor shaft, and t2 is the initial temperature of the motor shaft. δ The thickness of the composite material layer, α Its coefficient of thermal expansion is 9.

5. 10 -5 m / K.

4. The motor shaft structure according to claim 3, characterized in that: The thermal expansion Δδ of the composite material layer is 0.057-0.0855 mm.

5. The motor shaft structure according to claim 1, characterized in that: The gap between the motor shaft (1) and the rotor core (5) is 0.01mm-0.05mm.

6. The motor shaft structure according to claim 5, characterized in that: Two iron core pressure plates (2) are arranged at intervals along the axial direction on the motor shaft (1), and a rotor iron core (5) is arranged between the iron core pressure plates (2).

7. The motor shaft structure according to claim 1, characterized in that: A flat key (3) is provided on the motor shaft (1), and the flat key (3) is provided on the shaft segment that cooperates with the rotor core (5).

8. The motor shaft structure according to claim 6, characterized in that: The iron core pressure plate (2) is axially fixed to the motor shaft (1) by the steel ring (6).

9. A vehicle, characterized in that: It includes a generator, the generator comprising the motor shaft structure as described in any one of claims 1-8.

Images