A device for reducing motor shaft voltage

Abstract

The utility model relates to the field of automobile manufacturing, concretely relates to a device for reducing motor shaft voltage. The device contains motor rotor shaft, sacrifice bearing, conductive spring and motor casing, the sacrifice bearing is sleeved on the outside of electronic rotor shaft, motor casing is sleeved on the outside of sacrifice bearing, the conductive spring is arranged between the contact surface of sacrifice bearing and motor casing, the sacrifice bearing is arranged as sacrifice bearing inner ring, sacrifice bearing outer ring and sacrifice bearing rolling body, forms the path release of the shaft voltage on the motor rotor shaft through sacrifice bearing inner ring -sacrifice bearing rolling body -sacrifice bearing outer ring -conductive spring -motor casing. The utility model can more effectively reduce motor shaft voltage, and system reliability, durability is higher, and cost is low.

Description

Technical Field

[0001] This utility model relates to the field of automobile manufacturing, and specifically to a device for reducing motor shaft voltage. Background Technology

[0002] As automotive motors experience increasingly higher input voltages and greater power, especially in high-speed variable frequency drive motors, common-mode voltage and high-frequency harmonics couple to the shaft via parasitic capacitance, forming shaft voltage. When this shaft voltage exceeds the insulation threshold of the bearing lubricating oil, it breaks down the oil film, generating shaft current (EDM discharge), leading to bearing electrolytic corrosion, temperature rise, and noise, severely reducing motor lifespan and reliability. A conductive path is needed to divert the shaft voltage from the motor rotor shaft to the grounded motor housing. Traditional grounding carbon brushes and sacrificial bearings suffer from drawbacks such as rapid wear, poor reliability, high cost, and complex installation. Therefore, a low-cost, easy-to-install, and highly efficient device for suppressing shaft voltage is urgently needed to address the problem of bearing electrolytic corrosion and improve the reliability of the motor system. Utility Model Content

[0003] To address the aforementioned problems, this invention proposes a device for reducing motor shaft voltage. By improving the contact method of the sacrificial bearing, the risk of electro-corrosion is significantly reduced, and bearing durability is improved. A conductive spring replaces the grounding bracket. One side of the conductive spring makes uniform contact with the side of the sacrificial bearing, while the other side contacts the housing. The axial space between the housing and the sacrificial bearing compresses the conductive spring, generating a certain axial force. This ensures that all rolling elements of the sacrificial bearing are always reliably in contact with the inner and outer rings of the bearing, allowing all rolling elements to evenly bear the shaft current and avoiding electro-corrosion damage caused by a single bearing bearing the shaft current. The specific technical solution is as follows: A device for reducing motor shaft voltage includes a motor rotor shaft, a sacrificial bearing, a conductive spring, and a motor housing. The sacrificial bearing is sleeved on the outside of the motor rotor shaft, and the motor housing is sleeved on the outside of the sacrificial bearing. The conductive spring is disposed between the contact surfaces of the sacrificial bearing and the motor housing. The sacrificial bearing consists of an inner ring, an outer ring, and rolling elements, forming a path through which the shaft voltage on the motor rotor shaft is released: inner ring of the sacrificial bearing - rolling elements of the sacrificial bearing - outer ring of the sacrificial bearing - conductive spring - motor housing.

[0004] Furthermore, the conductive spring is a petal-shaped spring coil, with its lower contact surface fitting against the motor housing, and the upper contact surface of the petal spring contacting and fitting against the outer ring of the sacrificial bearing.

[0005] Furthermore, the conductive spring is a petal-shaped spring coil, with the upper contact surface of the motor housing contacting the petal spring and the lower contact surface contacting the inner ring of the sacrificial bearing.

[0006] Furthermore, the petal-shaped spring coil is provided with 12-20 petal-shaped spring pieces.

[0007] Furthermore, the petal-shaped spring coil is provided with 12 petal-shaped spring pieces.

[0008] This invention effectively prevents excessive shaft current from passing through other load-bearing bearings on the rotor shaft, thereby protecting the load-bearing bearings and reducing the risk of electro-corrosion failure of the sacrificial bearing. The beneficial effects are as follows: the conductive spring, through compression deformation, generates a certain axial force on the sacrificial bearing; one end of the conductive spring can be evenly attached to the conductive bearing, and the other end can be evenly attached to the motor housing, with good contact between the conductive spring and both, resulting in very low contact resistance, which facilitates the passage of shaft current; all rolling elements of the sacrificial bearing can participate in conductivity, reducing the discharge voltage between the rolling elements and the inner and outer rings, and avoiding electro-corrosion caused by the conductivity of a single rolling element; the sacrificial bearing diverts shaft current, thereby protecting the motor's load-bearing bearings from electro-corrosion damage. This invention can more effectively reduce motor shaft voltage, and the system has higher reliability, durability, and lower cost. Attached Figure Description

[0009] Figure 1 A schematic diagram of the structure of this utility model; Figure 2 Exploded view of the structure of this utility model; Figure 3 A schematic diagram of the conductive spring structure of this utility model.

[0010] Figure label: 1-Motor housing, 2-Conductive spring, 3-Sacrificial bearing, 4-Motor rotor shaft, 31-Sacrificial bearing outer ring, 32-Sacrificial bearing rolling element, 33-Sacrificial bearing inner ring. Detailed Implementation

[0011] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0012] like Figure 1-3As shown, a device for reducing motor shaft voltage includes a motor rotor shaft 4, a sacrificial bearing 3, a conductive spring 2, and a motor housing 1. The sacrificial bearing 3 is sleeved on the outside of the motor rotor shaft 4, and the motor housing 1 is sleeved on the outside of the sacrificial bearing 3. The conductive spring 2 is disposed between the contact surfaces of the sacrificial bearing 3 and the motor housing 1. The sacrificial bearing 3 is configured as a sacrificial bearing inner ring 33, a sacrificial bearing outer ring 31, and a sacrificial bearing rolling element 32, forming a path for releasing the shaft voltage on the motor rotor shaft 4 through the sacrificial bearing inner ring 33 - sacrificial bearing rolling element 32 - sacrificial bearing outer ring 31 - conductive spring 2 - motor housing 1.

[0013] like Figure 3 As shown, the conductive spring is a petal-shaped spring coil, with its lower contact surface fitting against the motor housing, and the upper contact surface of the petal-shaped spring piece fitting against the outer ring of the sacrificial bearing. The petal-shaped spring coil has 12-20 petal-shaped spring pieces. (The last sentence appears to be an example of a different spring coil.)

[0014] The preferred embodiments of this patent have been described in detail above. However, this patent is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this patent.

Claims

1. A device for reducing motor shaft voltage, characterized in that: The device includes a motor rotor shaft, a sacrificial bearing, a conductive spring, and a motor housing. The sacrificial bearing is sleeved on the outside of the motor rotor shaft, and the motor housing is sleeved on the outside of the sacrificial bearing. The conductive spring is disposed between the contact surfaces of the sacrificial bearing and the motor housing. The sacrificial bearing consists of an inner ring, an outer ring, and rolling elements. The shaft voltage on the motor rotor shaft is released through the path of the inner ring of the sacrificial bearing, the rolling elements of the sacrificial bearing, the outer ring of the sacrificial bearing, the conductive spring, and the motor housing.

2. The device for reducing motor shaft voltage according to claim 1, characterized in that: The conductive spring is a petal-shaped spring coil, with its lower contact surface fitting against the motor housing and its upper contact surface fitting against the outer ring of the sacrificial bearing.

3. The device for reducing motor shaft voltage according to claim 1, characterized in that: The conductive spring is a petal-shaped spring coil, with the upper contact surface of the motor housing contacting the petal spring and the lower contact surface contacting the inner ring of the sacrificial bearing.

4. A device for reducing motor shaft voltage according to any one of claims 1-3, characterized in that: The petal-shaped spring coil is provided with 12-20 petal-shaped spring pieces.

5. The device for reducing motor shaft voltage according to claim 4, characterized in that: The petal-shaped spring coil is provided with 12 petal-shaped spring pieces.

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