Motor rotor shaft pre-tightening structure and motor

Abstract

The invention provides a motor rotor shaft pre-tightening structure and a motor. The motor rotor shaft pre-tightening structure comprises a stator, a rotor shaft and a bearing. The stator is provided with a shaft hole, the first end of the rotor shaft is inserted into the stator inner cavity from the shaft hole, and the bearing is fixed on the rotor shaft and located in the stator inner cavity; the bearing and the rotor shaft divide the inner cavity of the stator into a closed compression cavity, the second end of the rotor shaft is provided with a communication groove part, one end of the communication groove part is communicated with the outer side of the stator, and the other end is communicated with the closed compression cavity; when the rotor shaft rotates, air on the outer side of the stator can be driven to enter the closed compression cavity along the communicating groove part, and due to the fact that the closed compression cavity is not provided with an outlet and only provided with an inlet in the communicating groove part, the rotor shaft continuously drives the air to enter the closed compression cavity in the rotating process, so that high-pressure air is formed in the closed compression cavity; the pressure directions of the high-pressure air acting on the rotor shaft and the stator are opposite, so that pretightening force between the rotor shaft and the stator is formed, and the stator and the rotor shaft can stably and reliably operate.

Description

Technical Field

[0001] The present application belongs to the field of motor technology, and more specifically, relates to a motor rotor shaft pre-tightening structure and a motor. Background Art

[0002] To ensure effective preload between the stator and the rotor, traditional motors usually use wave washers as components to provide preload. Due to its wave structure, the wave washer can elastically deform when subjected to axial pressure, thereby generating a continuous and stable compression force between the stator and the rotor.

[0003] Although the corrugated washers can effectively provide the required preload in the early stage of use, in the long-term use, due to the continuous vibration and heat generated by the motor during operation, the corrugated washer material is prone to gradually lose its original elasticity due to fatigue accumulation, resulting in a gradual decrease in preload over time. Secondly, the friction and wear inside the motor will also accelerate the loss of the corrugated washer, further weakening its ability to maintain preload. In addition, temperature changes in the working environment may also cause thermal expansion and contraction of the corrugated washer material, thereby affecting its size and the stability of the preload.

[0004] Under the combined influence of these factors, traditional motors often have the problem of insufficient preload after long-term operation. This will not only reduce the operating efficiency of the motor and increase energy consumption, but may also cause a series of faults such as increased vibration, increased noise and loose components, seriously shortening the service life of the motor. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a motor rotor shaft pre-tightening structure and a motor, so as to solve the technical problems existing in the prior art that the pre-tightening structure of the traditional motor is prone to failure and has a short service life.

[0006] To achieve the above purpose, the technical solution adopted in this application is:

[0007] A motor rotor shaft pre-tightening structure is provided, comprising:

[0008] A stator having an axial hole;

[0009] A rotor shaft, wherein a first end of the rotor shaft is inserted into the stator inner cavity from the shaft hole;

[0010] A bearing, fixed on the rotor shaft and located in the inner cavity of the stator;

[0011] The bearing and the rotor shaft separate the inner cavity of the stator to form a closed compression cavity;

[0012] A communicating groove is provided on the second end of the rotor shaft, one end of the communicating groove is communicated with the outside of the stator, and the other end is communicated with the sealed compression chamber.

[0013] As a further improvement of the above technical solution:

[0014] Optionally, the connecting groove portion is configured as a spiral groove, which is arranged along the circumference of the rotor shaft and extends spirally along the axial direction of the rotor shaft.

[0015] Optionally, the groove angle θ, groove depth h and groove width ω of the spiral groove extending spirally along the axial direction of the rotor shaft are all set to be the same, and the shaft hole gap between the rotor shaft and the stator is between 0.08 mm and 0.8 mm.

[0016] Optionally, the groove cross-sectional area A of the spiral groove is set according to the volume of the closed compression chamber, the operating working time and preset preload force of the rotor shaft, and the flow rate of the air in the installation environment under free convection state.

[0017] Optionally, the groove angle θ, groove depth h, groove width ω of the spiral groove and the groove body cross-sectional area A satisfy the following formula:

[0018] A = ω × h × cos (θ).

[0019] Optionally, the spiral grooves are arranged at equal spiral intervals around the axial direction of the rotor shaft.

[0020] Optionally, it also includes an airflow guide portion, which is arranged in the closed compression chamber and is used to guide the gas to flow into the closed compression chamber.

[0021] Optionally, the airflow guide portion is a guide groove provided on the inner wall of the stator inner cavity or an airflow guide blade provided on the rotor shaft.

[0022] Optionally, there are a plurality of airflow guide portions, and the airflow guide portions are arranged at intervals from each other around the axial direction of the rotor shaft.

[0023] The present application also provides a motor, comprising the above-mentioned motor rotor shaft pre-tightening structure.

[0024] The beneficial effects of a motor rotor shaft pre-tightening structure and a motor provided by the present application are:

[0025] The motor rotor shaft pre-tightening structure provided in the present application includes a stator, a rotor shaft and a bearing. The stator is provided with an axial hole, and the first end of the rotor shaft is inserted into the stator inner cavity from the axial hole. The bearing is fixed on the rotor shaft and is located in the stator inner cavity. In this way, the rotor shaft is fixed by the bearing, so that the rotor shaft can rotate in the stator inner cavity; the bearing and the rotor shaft separate the stator inner cavity to form a closed compression chamber, and a connecting groove is provided on the second end of the rotor shaft, one end of the connecting groove is connected to the outside of the stator, and the other end is connected to the closed compression chamber; in this way, when the rotor shaft rotates, it can drive the air outside the stator to enter the closed compression chamber along the connecting groove. Since the closed compression chamber has no outlet and only one inlet of the connecting groove, the rotor shaft continuously drives the air into the closed compression chamber during the rotation process, so that high-pressure air is formed in the closed compression chamber. Since the closed compression chamber is formed by the rotor shaft and the bearing separating the stator inner cavity, the pressure directions of the high-pressure air acting on the rotor shaft and the stator are opposite, thereby forming a preload between the rotor shaft and the stator, so that the stator and the rotor shaft can operate stably and reliably.

[0026] Compared with the traditional corrugated washer pre-tightening, the motor rotor shaft pre-tightening structure of the present application realizes the pre-tightening of the rotor shaft through compressed gas, and does not require an additional mechanical pre-tightening device, which simplifies the structure of the motor and reduces the number of components, thereby making the structure simpler and more compact. The air compression pre-tightening force generated by the rotation of the rotor shaft can also be automatically adjusted according to the operating speed of the motor, ensuring that appropriate pre-tightening force can be provided under different working conditions, and enhancing the performance stability of the motor under different working environments. Since the corrugated washer is removed, the friction between the rotor shaft and the corrugated washer is eliminated, and the energy loss in the traditional mechanical pre-tightening device is avoided, especially when running at high speed, which can better maintain the efficient operation of the motor. At the same time, it can also prevent the corrugated washer from failing due to fatigue, wear or high temperature effects during long-term use, reduce the maintenance cost of the motor, and improve the service life and working reliability of the motor.

[0027] The motor provided in the present application includes the above-mentioned motor rotor shaft pre-tightening structure, and therefore also has the advantages of the above-mentioned motor rotor shaft pre-tightening structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 A schematic cross-sectional view of the motor provided in this application;

[0030] Figure 2This is a schematic diagram of the main structure of the rotor shaft provided in this application;

[0031] Figure 3 for Figure 2 Schematic diagram of the local enlarged structure in.

[0032] Among them, the reference numerals in the figure are:

[0033] 1. Stator; 11. Shaft hole;

[0034] 2. Rotor shaft; 21. Bearing;

[0035] 22. Communication groove; 3. Compression chamber;

[0036] 4. Air flow guide part. DETAILED DESCRIPTION

[0037] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0040] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0042] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of the present invention.

[0043] In the following description, suffixes such as "circuit", "component", "assembly" or "unit" are used only to facilitate the description of the present invention and have no specific meanings. Therefore, they can be used in combination.

[0044] The present invention will be further described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0045] To solve the technical problems of easy failure and short service life of the preloaded structure of traditional motors, such as Figure 1 and Figure 2 As shown, the present application provides a motor rotor shaft pre-tightening structure, which includes a stator 1, a rotor shaft 2 and a bearing 21.

[0046] Specifically, the stator 1 is the fixed part of the motor, which is usually fixed in the motor housing. The stator 1 generally contains a motor coil. The stator 1 has an axial hole 11, and the first end of the rotor shaft 2 is inserted into the stator cavity from the axial hole 11. The second end portion of the rotor shaft 2 is fixed to the outside of the stator. The bearing 21 is installed on the rotor shaft 2. Generally, bearings are installed at both ends of the rotor shaft 2. The bearings are used to fix the rotor shaft so that the rotor shaft can be fixed and rotated in the stator cavity. Under the action of electromagnetic induction, the rotor shaft 2 is driven to rotate and output torque. As is well known, a certain gap must be ensured between the stator 1 and the rotor shaft 2 to avoid direct contact between the stator 1 and the rotor shaft 2 to generate friction and ensure efficient operation of the motor.

[0047] The bearing 21 and the rotor shaft 2 separate the inner cavity of the stator to form a closed compression chamber 3; the closed compression chamber 3 is used to contain compressed gas and withstand the pressure of the compressed gas.

[0048] Unlike conventional motors, a connecting groove 22 is provided on the rotor shaft 2, one end of the connecting groove 22 is connected to the outside of the stator 1, and the other end is connected to the closed compression chamber 3. When the rotor shaft 2 rotates, it can drive the air outside the stator 1 into the closed compression chamber 3 along the connecting groove 22. Since the closed compression chamber 3 has no outlet and only one inlet, the connecting groove 22, the rotor shaft 2 continuously drives the air into the closed compression chamber 3 during the rotation process, so that high-pressure air is formed in the closed compression chamber 3. Since the closed compression chamber 3 is formed by the rotor shaft 2 and the bearing 21 separating the stator inner cavity, the pressure directions of the high-pressure air acting on the rotor shaft 2 and the stator 1 are opposite, thereby forming a preload between the rotor shaft 2 and the stator 1, so that the stator and the rotor shaft can operate stably and reliably.

[0049] Compared with the traditional corrugated washer pre-tightening, the motor rotor shaft pre-tightening structure of the present application realizes the pre-tightening of the rotor shaft 2 through compressed gas, and does not require an additional mechanical pre-tightening device, which simplifies the structure of the motor and reduces the number of components, thereby making the structure simpler and more compact. The air compression pre-tightening force generated by the rotation of the rotor shaft 2 can also be automatically adjusted according to the operating speed of the motor, ensuring that appropriate pre-tightening force can be provided under different working conditions, and enhancing the performance stability of the motor under different working environments. Since the corrugated washer is removed, the friction between the rotor shaft 2 and the corrugated washer is eliminated, and the energy loss in the traditional mechanical pre-tightening device is avoided, especially when running at high speed, which can better maintain the efficient operation of the motor. At the same time, it can also prevent the corrugated washer from failing due to fatigue, wear or high temperature effects during long-term use, reduce the maintenance cost of the motor, and improve the service life and working reliability of the motor.

[0050] The motor rotor shaft preload structure of the present application is not only applicable to traditional motors, but can also be applied to scenarios requiring high-precision preload control, such as high-precision servo motors or high-speed motors, and has wide applicability.

[0051] like Figure 2 and Figure 3 As shown, in a specific embodiment of the present application, the connecting groove portion 22 is specifically a spiral groove extending spirally along the axial direction of the second end of the rotor shaft 2. When the rotor shaft 2 rotates, the spiral groove can simulate the working principle of a fan blade or an Archimedean conveyor, sucking and driving the gas at one end of the spiral groove to the other end, thereby continuously driving the air outside the stator into the closed compression chamber 3, so that the gas pressure in the compression chamber 3 increases, and the air pressure of the high-pressure air acts on the rotor shaft 2 and the stator 1 in opposite directions, thereby forming a pre-tightening force between the stator and the rotor shaft, so that the stator and the rotor shaft can operate stably and reliably.

[0052] like Figure 1 and Figure 2 As shown, in a specific embodiment of the present application, the spiral groove has an inlet end and an outlet end. The inlet end extends to the outside of the stator 1, and the outlet end extends into the closed compression chamber 3. For example, when the rotor shaft 2 rotates, the air outside the stator 1 can enter the closed compression chamber 3 along the spiral groove on the rotor shaft 2 to form high-pressure gas in the closed compression chamber 3, thereby generating a preload between the stator and the rotor shaft.

[0053] In a specific embodiment of the present application, the groove angle θ, groove depth h and groove width ω of the spiral groove extending spirally along the axial direction of the rotor shaft 2 are all set to be the same, so that the air flow velocity and flow rate can be kept stable, thereby keeping the preload force between the stator and the rotor shaft stable.

[0054] In a specific embodiment of the present application, the groove cross-sectional area A of the spiral groove is set according to the volume of the closed compression chamber 3, the operating working time of the rotor shaft 2 and the preset preload force, and the flow rate of the air in the installation environment under the free convection state. Among them, the groove cross-sectional area A of the spiral groove satisfies the following formula with the groove angle θ, the groove depth h, and the groove width ω:

[0055] A=ω×h×cos(θ)

[0056] The slot angle θ is the angle between the spiral slot side wall and the radial direction of the rotor shaft 2 .

[0057] The parameters of the spiral groove, such as θ, h and ω, are optimized through fluid mechanics simulation (such as CFD simulation) to achieve the best groove shape to maximize the gas intake and compression effect.

[0058] The volume of the closed compression chamber 3 is calculated according to the following formula:

[0059] PV=nRT

[0060]

[0061] Among them, P is the gas pressure in the closed compression chamber 3, V is the volume of the closed compression chamber 3, n is the number of moles of gas, R is the gas constant, and T is the temperature of the gas.

[0062] The pressure difference ΔP inside and outside the closed compression chamber 3 is calculated according to the following formula:

[0063] ΔP=PP 标准

[0064] Among them, P 标准 is standard atmospheric pressure.

[0065] Therefore, the air flow velocity V and flow rate Q generated by the spiral groove are:

[0066]

[0067] Q=A×V

[0068] Wherein, ΔP is the pressure difference between the inside and outside of the closed compression chamber 3, ρ is the density of the compressed gas, and A is the cross-sectional area of ​​the spiral groove.

[0069] Air mass flow rate entering the spiral groove per unit time And the change value ΔV of the air flow velocity entering the closed compression chamber 3 is:

[0070]

[0071] ΔV=VV 自然

[0072] Wherein, h is the operating time of the rotor shaft 2, V 自然 The air velocity in the installation environment under free convection is usually small, generally between 0.1-1 m / s.

[0073] Therefore, based on the above calculation results, the preload force F between the stator and rotor shafts can be calculated as:

[0074]

[0075] in, is the air mass flow rate entering the spiral groove per unit time, and ΔV is the change value of the air flow velocity entering the closed compression chamber 3.

[0076] In this way, when the preload force F between the stator and the rotor shaft is the preset preload force, the design relationship between the groove cross-sectional area A of the spiral groove and the pressure difference value ΔP inside and outside the closed compression chamber 3 can be derived through the above formula, so as to design the optimal groove angle θ, groove depth h, groove width ω through the groove cross-sectional area A, and design the optimal closed compression chamber 3 volume through the pressure difference value ΔP inside and outside the closed compression chamber 3; in addition, after the spiral groove and the groove angle θ, groove depth h, groove width ω of the spiral groove and the volume of the closed compression chamber 3 have been set, the preload force between the stator and the rotor shaft can also be adjusted according to the running working time h of the rotor shaft 2, so as to ensure that the appropriate preload force can be provided under different working conditions. This adaptability enhances the performance stability of the motor under different working environments.

[0077] In other specific embodiments of the present application, the communication groove 22 may also be an airflow driving blade extending spirally along the axial direction of the rotor shaft 2. When the rotor shaft 2 rotates, the airflow driving blade draws gas at one end of the rotor shaft 2 into the compression chamber 3.

[0078] In this embodiment, the length of the spiral groove is determined according to the assembly structure between the rotor shaft and the stator, as long as the inlet end of the spiral groove is outside the stator 1 and the outlet end is in the closed compression chamber 3; in addition, the shaft hole clearance between the rotor shaft 2 and the stator is between 0.08mm and 0.8mm, wherein it is generally preferably designed to be between 0.1mm and 0.5mm. The specific shaft hole clearance needs to be finely adjusted according to factors such as the size, speed, airflow requirements and manufacturing tolerance of the motor.

[0079] like Figure 1 As shown, in a specific embodiment of the present application, the motor rotor shaft pre-tightening structure further includes an airflow guide portion 4. The airflow guide portion 4 is disposed in the closed compression chamber 3, specifically, on the inner wall of the stator 1 or the rotor shaft 2. The airflow guide portion 4 is used to guide the gas to flow into the compression chamber 3, control the direction of the airflow, optimize the path of the airflow, and ensure that the gas is effectively sucked in and compressed during the rotation of the rotor shaft 2.

[0080] like Figure 1 As shown, in a specific embodiment of the present application, the airflow guide portion 4 is specifically a guide groove arranged on the inner wall of the stator 1 or an airflow guide blade arranged on the rotor shaft 2 to ensure effective guidance and compression of the airflow.

[0081] In a specific embodiment of the present application, there are multiple airflow guide parts 4, through which the compressed gas is guided to the bearing 21, so that the bearing 21 is subjected to effective pressure, which helps to generate a pre-tightening effect on the rotor shaft 2. The airflow guide parts 4 are arranged at intervals around the axis direction of the rotor shaft 2 to avoid interference between the airflow guide parts 4.

[0082] The present application also provides a motor, comprising the motor rotor shaft pre-tightening structure in the above specific embodiment. Therefore, the motor also has the advantages of the motor rotor shaft pre-tightening structure in the above specific embodiment.

[0083] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A motor rotor shaft pre-tightening structure, characterized in that: include: A stator (1) having an axial hole (11); A rotor shaft (2), wherein a first end of the rotor shaft (2) is inserted into the inner cavity of the stator through the shaft hole (11); A bearing (21) fixed on the rotor shaft (2) and located in the inner cavity of the stator; The bearing (21) and the rotor shaft (2) separate the inner cavity of the stator to form a closed compression cavity (3); A connecting groove (22) is provided on the second end of the rotor shaft (2), one end of the connecting groove (22) is connected to the outside of the stator (1), and the other end is connected to the closed compression chamber (3).

2. The motor rotor shaft pre-tightening structure according to claim 1, characterized in that: The connecting groove portion is configured as a spiral groove, which is arranged along the circumference of the rotor shaft (2) and extends spirally along the axial direction of the rotor shaft (2).

3. The motor rotor shaft pre-tightening structure according to claim 2, characterized in that: The groove angle θ, groove depth h and groove width ω of the spiral groove extending spirally along the axial direction of the rotor shaft (2) are all set to be the same, and the shaft hole clearance between the rotor shaft (2) and the stator (1) is between 0.08 mm and 0.8 mm.

4. The motor rotor shaft pre-tightening structure according to claim 3, characterized in that: The groove cross-sectional area A of the spiral groove is set according to the volume of the closed compression chamber (3), the operating working time and preset preload force of the rotor shaft (2), and the flow rate of the air in the installation environment under free convection.

5. The motor rotor shaft pre-tightening structure according to claim 4, characterized in that: The groove angle θ, groove depth h, groove width ω of the spiral groove and the groove cross-sectional area A satisfy the following formula: A = ω × h × cos (θ).

6. The motor rotor shaft pre-tightening structure according to claim 2, characterized in that: The spiral grooves are arranged at equal spiral intervals around the axial direction of the rotor shaft (2).

7. The motor rotor shaft pre-tightening structure according to any one of claims 1 to 6, characterized in that: It also comprises an airflow guide portion (4), which is arranged in the closed compression chamber (3) and is used to guide the gas to flow into the closed compression chamber (3).

8. The motor rotor shaft pre-tightening structure according to claim 7, characterized in that: The airflow guide portion (4) is a guide groove provided on the inner wall of the stator inner cavity or an airflow guide blade provided on the rotor shaft (2).

9. The motor rotor shaft pre-tightening structure according to claim 7, characterized in that: There are a plurality of airflow guide portions (4), and the airflow guide portions (4) are arranged at intervals from each other around the axial direction of the rotor shaft (2).

10. A motor, characterized in that: It comprises the motor rotor shaft pre-tightening structure as claimed in any one of claims 1 to 9.

Images