Thermally compensated bimetallic layer elastic assembly, brush assembly and electric machine

Abstract

The present application belongs to the technical field of green energy-saving motor and new composite material, and relates to a thermal compensation type bimetallic layer elastic assembly for high-efficiency energy-saving motor, and proposes a thermal compensation type bimetallic layer elastic assembly, a brush assembly and a motor. The elastic assembly comprises an elastic piece and a guide arm. The elastic piece can store elastic potential energy. A movable hinge point is arranged in the middle of the guide arm. The elastic output end of the elastic piece acts on one end of the guide arm, so that the other end of the guide arm generates displacement. The guide arm comprises a first metal layer and a second metal layer. The first metal layer and the second metal layer have different thermal expansion coefficients. The guide arm can selectively bend according to temperature. The structure can automatically adjust the carbon brush pressure at different temperatures, reduce arc loss, improve energy efficiency and reliability, and solve the problem that the elastic piece for applying pressure to the carbon brush is difficult to adapt to a wide temperature field, and the carbon brush contact force is unstable under high temperature, which affects the performance of the motor.

Description

Technical Field

[0001] This invention belongs to the field of green energy-saving motors and novel composite materials technology, specifically relating to a heat-compensated bimetallic layer elastic component for high-efficiency energy-saving motors, including a heat-compensated bimetallic layer elastic component, a brush assembly, and a motor. This application represents green technology, combining a bimetallic composite material with a heat-compensation structure, making it suitable for energy-saving motors and applicable to new energy vehicle drive systems. Background Technology

[0002] In the motor industry, conventional designs for maintaining carbon brush contact pressure or thermal compensation often rely on springs or mechanical tensioning systems. In existing brushless motors, the carbon brushes are fixed in place by springs made of a single material to maintain contact with the commutator. However, in automotive and high-temperature applications, springs made of a single material are significantly affected by temperature, leading to the following problems: spring force fluctuates with temperature changes, resulting in insufficient or excessive contact force; springs are prone to stress relaxation and fatigue at high temperatures, reducing carbon brush life; standard spring force is constant and cannot automatically compensate for force fluctuations caused by temperature changes, reducing motor reliability; limited thermal adaptability cannot meet the precise mechanical adjustment requirements of motors at different temperatures; space constraints limit the compact design of most motors, making it difficult to accommodate complex or additional mechanical components; motion control lacks innovation, with traditional motor springs only generating linear force; and the carbon brush holder cannot maintain optimal pressure over a wide temperature range (-40°C to 120°C). Based on these problems, a new motor component is needed to adapt to applications with large temperature spans and stable carbon brush contact force. Summary of the Invention

[0003] This invention proposes a heat-compensated bimetallic layer elastic component, a brush assembly, and a motor, which solves the problem in existing motors where the elastic component that applies pressure to the carbon brush is difficult to adapt to a wide range of temperature scenarios, and the unstable carbon brush contact force affects motor performance under high temperature conditions.

[0004] The technical solution of the present invention is as follows: A heat-compensated bimetallic layer elastic component includes an elastic element and a guide arm. The elastic element can store elastic potential energy and has an elastic output end. The guide arm has a movable hinge point in the middle. The elastic output end of the elastic element acts on one end of the guide arm to cause displacement at the other end of the guide arm. The guide arm includes a first metal layer and a second metal layer laminated together. The first metal layer and the second metal layer have different coefficients of thermal expansion. The guide arm can be selectively bent according to temperature.

[0005] The guide arm is bent so that the end of the guide arm that causes displacement tends to increase or decrease.

[0006] The first metal layer is made of Invar alloy 36, and the second metal layer is made of brass C360. Alternatively, the first metal layer may be made of 301 stainless steel, and the second metal layer may be made of C51000 phosphor bronze.

[0007] The first metal layer is made of 301 stainless steel, and the second metal layer is made of C17200 copper-beryllium alloy.

[0008] The connection method between the first metal layer and the second metal layer includes at least one of rolling, diffusion welding or brazing.

[0009] The elastic element is a spring, one end of which is fixed, the center of which is a mounting shaft, and the other end of which acts on the guide arm.

[0010] A brush assembly includes a heat-compensated bimetallic layer elastic component as described in any of the above embodiments. The brush assembly further includes a carbon brush housing and a carbon brush. The carbon brush is movably disposed within the carbon brush housing. The displacement end of the guide arm acts on one end of the carbon brush to move the carbon brush along the guide direction of the carbon brush housing.

[0011] Within an operating temperature range of -40°C to 120°C, the contact pressure variation of the carbon brush does not exceed ±10%. An electric motor comprising the thermally compensated bimetallic layer elastic component described in any of the above embodiments.

[0012] An electric motor, the electric motor comprising the brush assembly described in the above-described solution.

[0013] The working principle and beneficial effects of this invention are as follows: This invention discloses a thermally compensated bimetallic layer elastic component applied to a motor. The elastic component acts on the carbon brush to maintain a stable contact force. Using this thermally compensated bimetallic layer elastic component, the elastic force of the elastic element is indirectly applied to the carbon brush through a guide arm composed of different metal layers. The two metal layers of the guide arm have different coefficients of thermal expansion, so the guide arm bends when the temperature changes, thereby achieving thermal compensation for the elastic force of the carbon brush. Based on the above technical concept, this application can improve the stability of the elastic force acting on the carbon brush in response to temperature, provide moderate pressure in low-temperature environments to avoid excessive wear of the carbon brush, automatically increase or decrease pressure in high-temperature environments, automatically compensate for temperature-induced deviations, ensure stable contact between the carbon brush and the commutator, extend the service life of the carbon brush, reduce component wear and improve motor efficiency, and enable the motor to operate reliably over a wide temperature range. Simultaneously, it can be compactly integrated into the motor, avoiding complex mechanical compensation components and costly control systems, and solving the space limitations faced by traditional designs. Attached Figure Description

[0014] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0015] Figure 1 This is a schematic diagram of the motor structure in the prior art; Figure 2 This is a schematic diagram of the structure of a brush assembly in the prior art; Figure 3 This is a schematic diagram of the guide arm structure in this invention; Figure 4 This is a schematic diagram of the brush assembly arrangement structure in this invention; Figure 5 This is a schematic diagram of the guide arm bending structure in this invention; Figure 6 This is a schematic diagram of the guide arm reverse bending structure in this invention; Figure 7 This is a schematic diagram of the multi-state comparison structure of the guide arm brush assembly in this invention, showing schematic diagrams of the guide arm not bent, bent in the forward direction, and bent in the reverse direction; Figure 8 This is a graph showing the relationship between the curvature and thickness of the brass / Invar alloy bimetallic strip at 100℃ according to the present invention. Figure 9 Stress analysis of the bimetallic material at the operating temperature of this invention; Figure 10 The offset rate of the bimetallic guide arm at the operating temperature of this invention; Figure 11 Force analysis of the bimetallic guide arm at the operating temperature of this invention; Figure 12 The offset rate of the bimetallic guide arm at the operating temperature of this invention; In the diagram: 1. Elastic element, 2. Guide arm, 3. First metal layer, 4. Second metal layer, 5. Hinge point, 6. Carbon brush, 7. Carbon brush housing, 8. Torsion spring, 9. Motor housing, 10. Brush assembly, 11. Connector. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] To facilitate understanding of the improvements and advantages of the technical solution in this application, please refer to the accompanying drawings. Figure 1 and Figure 2The following describes the existing technology and its shortcomings. Brushed motors used in automobiles or industry generally include a motor housing 9, a rotor, a commutator, and a brush assembly 10. The brush assembly is generally made of a torsion spring 8 acting on the carbon brush to make the carbon brush contact the commutator. The torsion spring, which is made of a traditional single metal material, will cause unstable contact force at high temperatures due to stress relaxation and a decrease in elastic modulus. The spring force fluctuates with temperature changes, resulting in insufficient or excessive contact force. At high temperatures, the spring is prone to stress relaxation and fatigue, which shortens the life of the carbon brush. The standard spring force is constant and cannot automatically compensate for the force fluctuation caused by temperature changes, which reduces the reliability of the motor. Therefore, the motor has limited thermal adaptability and cannot meet the precise mechanical adjustment requirements of the motor at different temperatures. For example, the carbon brush contact pressure of ordinary steel springs decreases by about 20%–30% in the temperature range of 25℃ to 120℃, resulting in problems such as arcing, unstable commutation, and accelerated carbon brush wear. In addition, if thermal compensation design is to be implemented between the carbon brush and the commutator in the motor, an additional mechanical tensioning structure is required, as well as an additional active control system. This results in certain technical shortcomings in existing motors. The electrodes are limited by installation space, and the electrodes themselves are already compact, making it difficult to accommodate more complex or additional mechanical tensioning mechanisms. Setting up an active control system requires additional computing power from the mounting body and increases costs. It is evident that there is still considerable room for improvement and technical challenges in existing motor technologies.

[0018] As shown in the attached diagram. Figure 3 , Figure 5 and Figure 6 As shown, this embodiment proposes a thermally compensated bimetallic layer elastic component. The elastic component includes an elastic element 1 and a guide arm 2. The elastic element 1 can store elastic potential energy and has an elastic output end. The guide arm 2 has a movable hinge point 5 in the middle. The elastic output end of the elastic element 1 acts on one end of the guide arm 2 to cause displacement of the other end of the guide arm 2. The guide arm 2 includes a first metal layer 3 and a second metal layer 4 laminated together. The first metal layer 3 and the second metal layer 4 have different coefficients of thermal expansion. The guide arm 2 can be selectively bent according to temperature.

[0019] To address the shortcomings of existing technologies, this application proposes a thermally compensated bimetallic layer elastic component. The technical concept involves optimizing and improving the springs applied to carbon brushes in existing technologies. It employs an elastic element combined with a guide arm structure. The guide arm is a bimetallic structure, not a simple metal alloy, but a metal guide arm designed by layering a first metal layer and a second metal layer. The first and second metal layers have different coefficients of thermal expansion. When the temperature changes, the two metal layers will undergo different thermal expansion deformations. This difference in thermal expansion causes the guide arm to bend. A hinge point is optionally located in the middle of the guide arm. The hinge point can change position within a certain range depending on the magnitude of the elastic force applied by the elastic element. When the guide arm bends, the deformation caused by the bending is converted into displacement at one end of the guide arm based on leverage. The displaced end of the guide arm applies a force to the carbon brush. By dynamically adjusting the force according to temperature changes, a stable contact force is maintained between the carbon brush and the commutator.

[0020] It should be noted that the bonding surface between the first metal layer and the second metal layer can be a plane, an inclined surface, or a tortuous surface. The bending direction of the guide arm can vary depending on the bonding surface between the two metal layers. The design must ensure that the guide arm displaces at one end of the carbon brush after bending to achieve thermal compensation force control.

[0021] The above solution, with a compact internal space design for the motor, allows for the adjustment of thermally compensated control force by setting up a guide arm structure and using elastic components. This avoids the need for a complex mechanical tensioning structure and also eliminates the need for an active control system. It solves the shortcomings of existing technologies in a low-cost and simplified manner. At the same time, the thermally compensated bimetallic layer elastic component can effectively optimize the contact force stability of the carbon brushes inside the motor, thereby improving the performance of the carbon brushes and the motor and extending their service life.

[0022] The guide arm 2 is bent so that the end of the guide arm 2 that generates displacement tends to increase or decrease.

[0023] Based on the above embodiments, the bending of the guide arm can cause one end of the guide arm's displacement to tend to increase or decrease. This applies an additional force to the carbon brush, thus increasing or decreasing the force on the carbon brush, thereby matching temperature changes and ensuring that the carbon brush maintains stable contact pressure even in high-temperature environments. This achieves stable commutation, reduces sparking, and lowers wear.

[0024] The first metal layer 3 is made of Invar alloy 36, and the second metal layer 4 is made of brass C360.

[0025] In one possible embodiment, the first metal layer is made of Invar alloy 36 (Fe-36%Ni) and the second metal layer is made of brass C360 (Cu-40%Zn). The two metals are rolled together to form a metal strip. The total thickness and thickness ratio of the two metal layers need to be considered so that it has good deformation performance with temperature range changes, and produces an effect that can meet thermal compensation and effectively control contact force.

[0026] Let the thickness of the first metal layer be t1 and the thickness of the second metal layer be t2. The thickness ratio t1:t2 affects the curvature; the greater the difference between the two, the greater the degree of bending. As a metal layer with a high coefficient of thermal expansion, the thicker the second metal layer, the more pronounced its effect on increasing force as the temperature rises. However, the total thickness also affects the stiffness of the guide arm, and the material composition needs to reach an approximately balanced state.

[0027] The target bending angle or target force of the guide arm can be approximated using Timoshenko's bimetallic curvature theory. The temperature change Δ of each metal layer... T The curvature κ under the action can be estimated by the following formula:

[0028] In this formula: κ = curvature, α1 and α2 are the coefficients of thermal expansion of the first metal layer and the second metal layer, respectively; E1 E2 = Young's modulus, t1t2 = thickness of each layer, Δ T =Temperature change value, t (total thickness) = t1 + t2.

[0029]

[0030] Table 1: Material Properties Experimental conditions, Δ T The temperature change value is taken as 100℃, and the total thickness is taken as 1mm.

[0031] The use of bimetallic composite metal strips, with a typical material thickness ratio ranging from 0.8:1 to 2:1, represents a relatively balanced design. If the material composition ratio is less than 0.8:1, it will lead to insufficient force and weakened effect; if the ratio is greater than 2:1, it may result in excessive stiffness or excessive mechanical stress, and it will be difficult to achieve effective bonding.

[0032] Based on the above range, and through experiments, the curvature and corresponding expected effects were obtained by referring to three representative thickness combinations, as shown in the table below: The following table shows the curvature and expected results for different thickness ratios:

[0033] Table 2: Curvature ratio of bimetallic thickness and expected results Based on the above calculations, a material thickness ratio can be selected; if a more significant force is required to change with temperature, the third type (thickness ratio) is a generally feasible choice.

[0034] Curvature (κ) = the degree of bending per unit length of the strip Unit: mm 1 (or 1 / mm) Example: κ = 0.005 mm - 1表示：

[0035] When the temperature change ΔT = 100℃, the guide arm will bend into an arc with a radius of approximately 200mm. The total offset will depend on the guide arm length and material composition.

[0036] The mid-span offset of the guide arm is approximately:

[0037] The strip length L = 20 mm, and the curvature = 0.005 mm - 1.

[0038]

[0039] When the temperature increases by 100°C, the offset at the end of the guide arm is approximately 0.25 mm. This offset is converted into additional carbon brush force through the geometry of the guide arm lever. If the lever ratio is 4:1, the carbon brush offset is equivalent to approximately 1.0 mm, which is sufficient to cause a significant change in carbon brush pressure. Curvature κ = 0.005 mm - 1在电机应用中较为合理。计算表明，采用 A thickness ratio of 2:1 can achieve a greater force / offset; if smoother control is required, a thickness ratio of 0.8:1 or 1:1 will suffice.

[0040] For a guide arm of length L with constant curvature, it can be equivalent to a cantilever beam. The offset of its free end, i.e. the displacement of the bimetallic strip end, is calculated as follows:

[0041] The end offset for different thickness ratios can be referenced in the table below:

[0042] Table 3: Thickness ratio (bimetallic guide arm offset rate) The curvature versus thickness relationship of the brass / Invar bimetallic strip at 100℃ is shown in Figure 8; the stiffness k` of the guide arm, which is equivalent to that of a cantilever beam, is calculated as follows:

[0043] In this formula, EI = E1 I1 + E2 I2 Where I1 and I2 are the moments of inertia of the Invar alloy and brass sections about the neutral axis, respectively; the position of the neutral axis is calculated by "equilibrium area × centroid distance". The stiffness calculated by this formula is in N / mm.

[0044] The generated force (F): If the free end offset δ is limited by a rigid load (such as a carbon brush in a motor), the force control formula is as follows: F ≈ k、. δfree This gives the upper limit of the force exerted by the guide arm on the displacement end of the carbon brush.

[0045] In one possible specific embodiment, the material is: Invar alloy 36 (elastic modulus of elasticity). E 1 = 141 GPa, coefficient of thermal expansion α 1 =1.2 e-6 Brass C360 (elastic modulus) E 2 = 100 GPa, coefficient of thermal expansion α2 = 19 e-6 ) Thickness ratio: 1:1, assuming t1=t 2=1mm width: b =10mm length: L= 20mm Stress-free temperature: T 0 = 20℃ (assuming ambient temperature) Temperature range: -40℃ to 120℃, 8 zones in total. Timoshenko's bimetallic theory requires a reference temperature (usually the stress-free temperature T0) and the actual temperature T0. The curvature and offset are calculated from the temperature change ΔT = TT.

[0046] Temperature range: ΔT = T - T0 = T - 20 Temperature T values ​​(°C): -40, -10, 20, 50, 80, 110, 120 (including a reference temperature of 20°C, approximately 8 intervals) Temperature change ΔT values ​​(°C): -60, -30, 0, 30, 60, 90, 100 The estimated force on the guide arm under simulated working conditions is as follows:

[0047] Table 4: Calculation Table of Estimated Force Characteristics at Operating Temperature Stress analysis of bimetallic materials at operating temperature, reference Figure 9 ; The offset rate of the bimetallic guide arm at operating temperature is shown in Figure 10. When ΔT>0 (temperature rises), the double-layer metal guide arm bends in one direction (typically, the brass is on the outside and the tile alloy is on the inside). To keep it straight, a positive force needs to be applied.

[0048] When ΔT < 0 (temperature decreases), the bimetallic strip bends in the opposite direction (brass shrinks more, and the guide arm bends in the opposite direction). To keep it straight, a negative force needs to be applied.

[0049] Positive force represents the force required to prevent the bimetallic strip from bending in the "normal direction." Negative force means the force required to prevent the bimetallic strip from bending in the "opposite direction".

[0050] Referring to Figures 5 to 7, schematic diagrams are shown of the guide arm in its unbent, forward-bent, and reverse-bent positions. The diagrams also show the guide arm in different positions with varying preloads on the elastic element. Forward bending corresponds to increased temperature, bending in the "normal direction" to increase compensation for carbon brush pressure. Reverse bending corresponds to decreased temperature, thus reducing compensation for carbon brush pressure. It should be noted that all these compensations aim to maintain a stable contact force on the carbon brush. The bending direction of the guide arm depends on the arrangement of the metal layers: when the low thermal expansion layer is on top, the guide arm bends upward with increasing temperature, thereby increasing carbon brush pressure; when the high thermal expansion layer is on top, the guide arm bends downward, which can reduce initial pressure. The fulcrum of the guide arm can be formed through a hinged or elastic connection structure, allowing for controlled angle shifting of the guide arm at different temperatures.

[0051] As the temperature rises, the carbon brush will move with the guide arm displacement end (usually toward the commutator). When the temperature decreases, the carbon brush will move in the opposite direction as the guide arm displacement end moves.

[0052] At room temperature (25°C), the reference carbon brush force applied by the guide arm is 18-20 N. As the temperature rises, the differential expansion of the two layers of bimetallic material causes the guide arm to bend. This bending deformation is transmitted through the guide arm, thereby increasing the carbon brush force. For example, at 120°C, the carbon brush force is increased by at least 50% compared to the reference value, ensuring stable electrical contact and reducing commutator sparking. Under the same operating conditions, compared with a conventional single-layer steel spring, the bimetallic guide arm structure of this application can increase carbon brush life by approximately 30%-50%, reduce arc intensity at high temperatures by approximately 40%, and control carbon brush pressure fluctuation within ±10%.

[0053] Based on this embodiment and the existing technology that only uses traditional metal springs, the effects are shown in the table below:

[0054] Table 5: Example of Comparison Results The first metal layer 3 is made of 301 stainless steel, and the second metal layer 4 is made of C51000 phosphor bronze.

[0055] In other possible embodiments, the first metal layer is made of 301 stainless steel, with a coefficient of thermal expansion of approximately 16 × 10⁻⁶ / K and a Young's modulus of approximately 195 GPa; the second metal layer is made of C51000 phosphor bronze, with a coefficient of thermal expansion of approximately 18 × 10⁻⁶ / K. The Young's modulus is approximately 110 GPa.

[0056] Based on the above theory, the calculation process is as follows: 1) Curvature κ (mm - 1 )=5.41-7× ΔT 2) Offset δ (mm) = 0.0001082 × ΔT 3) Force F(N) = 0.0413 × ΔT. The table below shows the forces corresponding to different ΔT values:

[0057] Table 6: Calculation Table of Estimated Force Characteristics at Different Operating Temperatures The force exerted by the bimetallic guide arm at the operating temperature is shown in Figure 11, and the offset rate is shown in Figure 12. This combination of materials enables balanced offset and improves fatigue resistance. This flexible component is suitable for automotive motors with high operating cycles: after undergoing over 100,000 thermal cycles in a temperature range of -40°C to 120°C, the carbon brush force remains within ±10% of the target value.

[0058] The first metal layer 3 is made of 301 stainless steel, and the second metal layer 4 is made of C17200 copper-beryllium alloy.

[0059] In other possible embodiments, the first metal layer is made of 301 stainless steel and the second metal layer is made of C17200 copper-beryllium alloy. The above combination of metal layers is suitable for motors that require higher contact force in high-temperature environments. The bimetallic guide arm can not only significantly improve the force, but also maintain the fatigue life of more than 200,000 thermal cycles.

[0060] In the above possible embodiments, it should be further noted that the thickness of the bimetallic layer can be adjusted within the range of 0.2mm to 1.0mm to meet different force requirements. The geometry of the guide arm can be optimized according to requirements. The guide arm can not only be integrated with the carbon brush, but also with the internal thermal cut-off mechanism, overload protection device, or bearing preload system of the motor.

[0061] The connection method between the first metal layer 3 and the second metal layer 4 includes at least one of rolling, diffusion welding or brazing.

[0062] Based on the above embodiments, the connection method of stacking the first metal layer and the second metal layer into a whole is optional. One of rolling, diffusion welding and brazing can be used, but it is not a limitation and other connection methods can also be adopted.

[0063] The elastic element 1 is a spring, one end of which is fixed, the center of which is the mounting shaft, and the other end of which acts on the guide arm 2.

[0064] Based on the above embodiments, the elastic element is a spring, and further a torsion spring, with a mounting shaft in the middle, one end of which is fixed and the other end acts on the guide arm.

[0065] A brush assembly 10 includes a heat-compensated bimetallic layer elastic component as described in any of the above embodiments. The brush assembly also includes a carbon brush housing 7 and a carbon brush 6. The carbon brush 6 is movably disposed within the carbon brush housing 7. The displacement end of the guide arm 2 acts on one end of the carbon brush 6 to move the carbon brush 6 along the guiding direction of the carbon brush housing 7.

[0066] Within an operating temperature range of -40℃ to 120℃, the contact pressure variation of the carbon brush does not exceed ±10%. This application also proposes a brush assembly, as shown in the accompanying drawings. Figure 4As shown in Figure 7, the components of the brush assembly refer to the structure of the prior art brush in Figure 2, including the heat-compensated bimetallic layer elastic component in any of the above embodiments. Further, the brush assembly includes a carbon brush housing and a carbon brush. The displacement end of the guide arm acts on the carbon brush, and the carbon brush presses against the commutator under the guidance of the carbon brush housing. The carbon brush housing also provides some protection for the carbon brush. Through the compensation of the elastic component, the pressure variation between the carbon brush and the commutator within the operating temperature range of -40℃ to 120℃ does not exceed ±10%.

[0067] An electric motor, wherein the electric motor comprises a heat-compensated bimetallic layer elastic component as described in any of the above embodiments.

[0068] An electric motor, the electric motor including the brush assembly described in the above embodiments.

[0069] This application also proposes a motor that may include the heat-compensated bimetallic elastic component or brush assembly described in the above embodiments, and the motor may also include conventional motor components such as motor housing and connectors.

[0070] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A thermally compensated bimetallic layer elastic component, characterized in that, The elastic component includes an elastic element (1) and a guide arm (2). The elastic element (1) can store elastic potential energy and has an elastic output end. The guide arm (2) has a movable hinge point in the middle. The elastic output end of the elastic element (1) acts on one end of the guide arm (2) to cause the other end of the guide arm (2) to be displaced. The guide arm (2) includes a first metal layer (3) and a second metal layer (4) laminated together. The thickness ratio of the first metal layer (3) and the second metal layer (4) is between 0.8:1 and 2:

1. The first metal layer (3) and the second metal layer (4) have different coefficients of thermal expansion. The guide arm (2) can be selectively bent according to temperature. In the temperature range of -40℃ to 120℃, the other end of the guide arm (2) can keep the force on the carbon brush within ±10% of the target value.

2. The thermally compensated bimetallic layer elastic component according to claim 1, characterized in that, The guide arm (2) is bent so that the end of the guide arm (2) that produces displacement tends to increase or decrease.

3. The thermally compensated bimetallic layer elastic component according to claim 1 or 2, characterized in that, The first metal layer (3) is made of Invar alloy 36, and the second metal layer (4) is made of brass C360.

4. The thermally compensated bimetallic elastic component according to claim 1 or 2, characterized in that, The first metal layer (3) is made of 301 stainless steel, and the second metal layer (4) is made of C51000 phosphor bronze.

5. The heat-compensated bimetallic elastic component according to claim 1 or 2, characterized in that, The first metal layer (3) is made of 301 stainless steel, and the second metal layer (4) is made of C17200 copper-beryllium alloy.

6. The thermally compensated bimetallic elastic component according to claim 1 or 2, characterized in that, The connection method between the first metal layer (3) and the second metal layer (4) includes one of rolling, diffusion welding or brazing.

7. The thermally compensated bimetallic layer elastic component according to claim 6, characterized in that, The elastic element (1) is a spring, one end of which is fixed, the center of which is the mounting shaft, and the other end of which acts on the guide arm (2).

8. A brush assembly, characterized in that, The brush assembly includes a heat-compensated bimetallic layer elastic component as described in any one of claims 1 to 7. The brush assembly further includes a carbon brush housing and a carbon brush. The carbon brush is movably disposed within the carbon brush housing. The displacement end of the guide arm (2) acts on one end of the carbon brush to move the carbon brush along the guiding direction of the carbon brush housing.

9. An electric motor, characterized in that, The motor includes the thermally compensated bimetallic layer elastic component as described in any one of claims 1 to 7.

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