Motor and method for realizing transportation support of motor

Abstract

An electric machine includes a stator (101), a rotor (102), and bearings (103) configured to rotatably support the rotor relative to the stator. The motor comprises a force generating device (104) attached to the stator and comprising an actuator (105) for directing an axial force to an end of a shaft (106) of the rotor. The actuator may be hydraulically, pneumatically, or electrically driven. When an electric machine is transported by using, for example, a trailer, truck, locomotive or vessel and a transport support is required, the actuator is controlled to direct an axial force to the end of the shaft to eliminate clearance with the bearing and thereby protect the bearing from damage during transport. Advantageously, a physical air gap exists between the actuator and the end of the shaft when the motor is used for the purpose of its use as a motor or generator.

Description

Technical Field

[0001] The present disclosure generally relates to electric motors. More specifically, the present disclosure relates to an electric motor comprising a stator, a rotor, a bearing configured to rotatably support the rotor relative to the stator, and a device for providing transport support to protect the motor from damage when subjected to external vibration and / or impact while the motor is being transported or stationary. Furthermore, the present disclosure relates to a method for providing transport support for the motor. Furthermore, the present disclosure relates to an electric drive. Background Art

[0002] When a motor is stationary and is transported as part of an application system (such as a working machine) using a trailer, truck, locomotive, or ship, there is a possibility of damage to the motor's bearings. In particular, in large motors with significantly higher rotor masses, if the bearings are not properly protected, there is a significant risk of damage due to external vibrations and shocks. The reason for this damage is that all rolling bearings have clearances that allow them to be lubricated and rotate with low rolling resistance. Therefore, external vibrations and shocks can cause the bearing surfaces to collide with each other and be damaged.

[0003] To avoid the type of bearing damage described above, the motor's rotor needs to be mechanically supported to prevent the bearing surfaces from colliding with each other during transport or being subjected to external vibrations and / or shocks while the motor is stationary. Providing adequate mechanical support can be particularly challenging when the motor is part of an application system (such as a working machine) that is being transported or subjected to external vibrations and / or shocks. Summary of the Invention

[0004] The following presents a simplified summary of the invention to provide a basic understanding of certain aspects of various embodiments. This summary is not an extensive overview of the present invention. It is neither intended to identify key or essential elements of the present invention nor to define the scope of the present invention. The following summary merely presents some concepts of the present invention in a simplified form as a prelude to a more detailed description of the exemplary embodiments.

[0005] According to the present invention, a novel motor is also provided, comprising:

[0006] -stator;

[0007] a rotor rotatably supported relative to the stator and configured to electromagnetically interact with the stator to generate torque in response to one or more currents supplied to the motor;

[0008] - bearings configured to rotatably support the rotor relative to the stator; and

[0009] A force generating device mechanically attached to the stator and comprising an actuator configured to direct an axial force to the end of the shaft of the rotor in order to eliminate clearance with the bearings.

[0010] When the motor is subjected to external vibration and / or shock during transportation or while stationary, the actuator is controlled to direct axial force toward the end of the shaft to eliminate clearance with the bearings, thereby preventing the bearing surfaces from colliding with each other and protecting the bearings from damage. When the motor is used for its intended function as a motor or generator, the force generating device is advantageously configured such that a physical air gap exists between the actuator and the end of the shaft.

[0011] In the above-described motors, the fact that many bearings that provide radial support can also bear axial loads is utilized to support the rotor when the motor is transported or subjected to external vibration and / or shock when stationary. For example, when the outer ring of the bearing is axially displaced from the inner ring of the bearing, the rolling elements having a rounded or convex shape naturally eliminate radial clearance.

[0012] The force generating device may be a hydraulic device, wherein the actuator includes a hydraulic piston. Alternatively, the force generating device may be a pneumatic device with a pneumatically driven actuator or an electrical device with a magnetically driven actuator. It should be noted that embodiments of the present invention are not limited to any particular manner or manners of directing the axial force to the end of the motor shaft.

[0013] According to the present invention, a novel electric drive is also provided, comprising a motor and a converter configured to drive the motor. The motor is a motor according to an embodiment, comprising a state detection device configured to generate a state signal indicating whether an actuator is directing an axial force toward the end of a rotor shaft. The converter is configured to receive the state signal and refrain from supplying voltage to the motor when the actuator is directing the axial force toward the end of the rotor shaft, thereby preventing inadvertent and potentially damaging activation of the motor when the force generating device is active.

[0014] According to the present invention, a new method for achieving transportation support of a motor is also provided, the motor comprising:

[0015] -stator;

[0016] a rotor rotatably supported relative to the stator and configured to electromagnetically interact with the stator to generate torque in response to current supplied to the motor; and

[0017] - bearings configured to rotatably support the rotor relative to the stator.

[0018] The method according to the invention comprises directing an axial force to the end of the shaft of the rotor to eliminate clearance with the bearing by means of a force generating device mechanically attached to the stator and comprising an actuator configured to direct the axial force to the end of the shaft of the rotor.

[0019] In this document, the term "transport support" is intended to mean a support arrangement suitable for protecting the electric machine from damage during transport and in other situations where the machine is at rest and is subject to external vibrations and / or shocks.

[0020] Exemplary and non-limiting embodiments are described in the accompanying dependent claims.

[0021] The exemplary and non-limiting embodiments, both as to construction and method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplary and non-limiting embodiments when read in connection with the accompanying drawings.

[0022] The verbs "to comprise" and "to include" are used in this document as open limitations that neither exclude nor require the existence of unrecited features.

[0023] The features recited in the dependent claims may be freely combined with one another unless explicitly stated otherwise.

[0024] Furthermore, it is to be understood that throughout this document, the use of "a" or "an" (ie in the singular) does not preclude a plurality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Exemplary and non-limiting embodiments and their advantages will be explained in more detail below by way of example and with reference to the accompanying drawings, in which:

[0026] Figure 1 shows an electric machine according to an exemplary and non-limiting embodiment,

[0027] Figure 2 shows an electric machine according to an exemplary and non-limiting embodiment, and

[0028] Figure 3 A flow chart illustrating a method for implementing transport support for an electric machine according to an exemplary and non-limiting embodiment is shown. DETAILED DESCRIPTION

[0029] The specific examples provided in the description below should not be construed as limiting the scope and / or applicability of the appended claims.Unless expressly stated otherwise, the lists of examples and groups of examples provided in the description are not exhaustive.

[0030] Figure 1A portion of an electric motor 100 is shown according to an exemplary and non-limiting embodiment. The electric motor 100 includes a stator 101 and a rotor 102 rotatably supported relative to the stator 101 and configured to electromagnetically interact with the stator to generate torque in response to current supplied to the motor. The electric motor 100 may be, for example, an induction motor, a permanent magnet motor, a reluctance motor, or a direct current (DC) motor. Figure 1 , only the non-driven "ND" end of the motor 100 is shown. The stator 101 is shown in a cross-sectional view, wherein the geometric cross-sectional plane is parallel to the yz plane of the coordinate system 199. The stator 102 includes a stator core structure 118 and a stator winding 119. The axial direction of the motor 100 is parallel to the z-axis of the coordinate system 199. The motor 100 includes bearings that are configured to rotatably support the rotor 102 relative to the stator 101. Figure 1 In the embodiment, the bearing at the ND end is indicated by reference numeral 103. In this exemplary case, the bearing 103 is a ball bearing. Accordingly, the bearing at the drive "D" end of the motor 100 can be a ball bearing. Figure 1 The bearing at the D end is not shown.

[0031] The motor 100 includes a force generating device 104 mechanically attached to the stator 101 and including an actuator 105 configured to direct an axial force to the end of the shaft 106 of the rotor 102 to eliminate clearance with the bearings of the motor 100. Figure 1 , the end of shaft 106 is shown in cross-section, with the geometric cross-section plane parallel to the yz plane of coordinate system 199. In this exemplary case, the force generating device is located at the ND end of the motor. However, the force generating device can also be configured to direct the axial force to the end of the shaft at the D end of the motor. For example, there can be a gear or sheave attached to the end of the shaft of the motor, and the force generating device can be configured to direct the axial force to the end of the shaft that protrudes through the gear or sheave.

[0032] exist Figure 1 In the exemplary motor 100 shown, the force generating device 104 is a hydraulic device including a hydraulic cylinder 107, and the actuator 105 of the force generating device 104 includes a hydraulic piston 108. Figure 1, hydraulic cylinder 107 is shown in a cross-sectional view, wherein the geometric cross-sectional plane is parallel to the yz plane of coordinate system 199. In this exemplary embodiment, hydraulic cylinder 107 is a single-acting hydraulic cylinder capable of pushing hydraulic piston 108 toward the end of rotor shaft 106 in the negative z-direction of coordinate system 199. Force generating device 104 includes a return spring 109 configured to push the hydraulic piston away from the end of rotor shaft 106 in the positive z-direction of coordinate system 199. The force generating device of the motor according to the exemplary and non-limiting embodiment may also be an electromagnetic device including an electromagnet for generating an axial force directed toward the end of the motor's shaft. Furthermore, the force generating device of the motor according to the exemplary and non-limiting embodiment may also be a pneumatic device including a pneumatically driven actuator for generating an axial force directed toward the end of the motor's shaft.

[0033] exist Figure 1 In the exemplary motor 100 shown, the force generating device 104 includes a pressurizer 110 capable of maintaining the pressure of the hydraulic fluid in the absence of external energy, such as when the motor 100 is being transported or subjected to external vibration and / or shock and no external energy is available. In this exemplary embodiment, the pressurizer 110 includes a body and a flexible bag 120 within the body that contains the hydraulic fluid. The force generating device 104 is activated by pumping compressed flexible material 111 (e.g., air or other gas) into the space between the body and the flexible bag 120. The flexible material 111 directs pressure into the flexible bag 120, thereby maintaining the pressure of the hydraulic fluid. The force generating device 104 is deactivated by allowing the pressure of the flexible material 111 to drop. Depending on the requirement and availability or unavailability of external energy, different means for controlling the force generating device 104 are possible, such as an electrically driven hydraulic pump, a spring-operated pressurizer, etc.

[0034] exist Figure 1 In the exemplary motor 100 shown, the force generating device 104 includes a collar section 112 attached to a bearing shield 113 of the motor 100 and a flange section 114 connected to the collar section. Figure 1 , collar segment 112 and flange segment 114 are shown as a cross-sectional view, wherein the geometrical cross-section plane is parallel to the yz plane of coordinate system 199. Hydraulic cylinder 107 is attached to flange segment 114, and actuator 105 protrudes through an aperture of flange segment 114 toward the end of shaft 106 of the rotor.

[0035] Figure 1 The exemplary electric machine 100 shown includes a protective element 117 between the actuator 105 of the force generating device 104 and the end of the shaft 106 of the rotor. Figure 1, protective element 117 is shown as a cross-sectional view, where the geometric cross-sectional plane is parallel to the yz plane of coordinate system 199. Protective element 117 is made of a material softer than the material of rotor shaft 106 and protects the rotor shaft from deformation. Protective element 117 can be made of, for example, aluminum or nylon.

[0036] The electric machine according to the exemplary and non-limiting embodiment comprises a state detection device 115 configured to generate a state signal 116 indicating directly or indirectly whether the actuator 105 is directing an axial force to the end of the shaft 106 of the rotor 102. Figure 1 In the exemplary motor shown, the state detection device 115 includes a pressure sensor configured to detect the pressure of the hydraulic fluid and generate a state signal 116 based on the detected pressure. The state detection device of the motor according to the exemplary and non-limiting embodiment may also include a position sensor configured to detect the axial position of the actuator of the force generating device, or a mechanical sensor configured to detect mechanical stress or deformation in the actuator or in some other suitable part of the force generating device, such as a strain gauge. In the exemplary case where the force generating device is an electromagnetic force generating device, the state detection device may include a device for generating a state signal based on the current of the electromagnetic force generating device. In the exemplary case where the force generating device is a pneumatic force generating device, the state detection device may include, for example, a gas pressure sensor or a device for generating a state signal based on the operation of a device for supplying pressurized gas (e.g., air) to the pneumatic force generating device. It should be noted that the above-mentioned state signal can be generated in a variety of ways, and embodiments of the present invention are not limited to any one or more specific ways of generating the state signal.

[0037] The above-described status signal 116 is advantageous in an electric drive including an electric motor 100 and a converter 132 configured to drive the electric motor 100. The converter 132 is configured to receive the status signal 116 and refrain from supplying voltage to the electric motor 100 when the actuator 105 directs an axial force to the end of the shaft 106, so as to avoid unintentional and potentially destructive startup of the electric motor 100 when the force generating device 104 is activated.

[0038] In addition, the status signal 116 can be used as a feedback signal supplied to a control device that is configured to control the force generating device. The feedback signal can be used, for example, to monitor that the force generating device is operating correctly in response to control actions performed by the control device. Hidden incorrect operation of the force generating device may cause bearing damage during transportation and other situations when the motor is at rest and is subject to external vibration and / or shock. The feedback signal can be used to generate an alarm in the event that the force generating device is operating incorrectly. According to an exemplary and non-limiting embodiment, the motor includes a control device 150 that is configured to control the force generating device, receives the status signal 116 and generates an alarm in response to the following situation: i) the force generating device has been controlled to direct axial force to the end of the shaft, but ii) the status signal 116 indicates that no axial force is being directed to the end of the shaft.

[0039] Figure 2 A portion of an electric motor 200 is shown according to an exemplary and non-limiting embodiment. The electric motor 200 includes a stator 201 and a rotor 202 rotatably supported relative to the stator 201 and configured to electromagnetically interact with the stator to generate torque in response to current supplied to the motor. Figure 2 , only the non-driven "ND" end of the motor 200 is shown. The stator 201 is shown in a cross-sectional view, wherein the geometric cross-sectional plane is parallel to the yz plane of the coordinate system 299. The stator 202 includes a stator core structure 218 and a stator winding 219. The axial direction of the motor 200 is parallel to the z-axis of the coordinate system 299. The motor 200 includes bearings that are configured to rotatably support the rotor 202 relative to the stator 201. Figure 2 In the embodiment of the present invention, the bearing at the ND end is indicated by reference numeral 203. In this exemplary embodiment, the bearing 203 is a spherical roller bearing. Accordingly, the bearing at the drive "D" end of the motor 200 can be a spherical roller bearing. Figure 2 The bearing at the D end is not shown.

[0040] The motor 200 includes a force generating device 204 mechanically attached to the stator 201 and including an actuator 205 configured to direct an axial force to the end of the shaft 206 of the rotor 202 to eliminate clearance with the bearings of the motor 200. Figure 2 , the end of the shaft 206 is shown as a cross-sectional view, wherein the geometric cross-sectional plane is parallel to the yz plane of the coordinate system 299. In this exemplary case, the force generating device is located at the ND end of the motor. The force generating device 204 includes a hydraulic cylinder 207, and the actuator 205 of the force generating device includes a hydraulic piston 208. Figure 2, hydraulic cylinder 207 is shown as a cross-sectional view, wherein the geometrical cross-sectional plane is parallel to the yz plane of coordinate system 299. In this exemplary case, hydraulic cylinder 207 is a double-acting hydraulic cylinder capable of pushing hydraulic piston 208 toward the end of the rotor's shaft 206 in the negative z-direction of coordinate system 299 and capable of moving the hydraulic piston away from the end of the rotor's shaft in the positive z-direction of coordinate system 299.

[0041] exist Figure 2 In the exemplary motor 200 shown, the force generating device 204 includes pressurizers 210 and 230 that are capable of maintaining the pressure of the hydraulic fluid in the different compartments of the hydraulic cylinder 207 without external energy. In this exemplary case, each of the pressurizers 210 and 230 includes a body and a flexible bag inside the body that contains the hydraulic fluid.

[0042] Figure 3 A flow chart is shown of a method for implementing transport support of an electric motor according to an exemplary and non-limiting embodiment, the electric motor comprising: a stator; a rotor rotatably supported relative to the stator and configured to electromagnetically interact with the stator to generate torque in response to current supplied to the motor; and bearings configured to rotatably support the rotor relative to the stator.

[0043] The method comprises directing 301 an axial force to the end of the shaft of the rotor to eliminate clearance with a bearing by means of a force generating device mechanically attached to the stator and comprising an actuator configured to direct the axial force to the end of the shaft of the rotor.

[0044] In a method according to an exemplary and non-limiting embodiment, the force generating device comprises a hydraulic cylinder and the actuator of the force generating device comprises a hydraulic piston.

[0045] In a method according to an exemplary and non-limiting embodiment, the hydraulic cylinder is a double-acting hydraulic cylinder capable of pushing a hydraulic piston toward the end of the shaft of the rotor and capable of moving the hydraulic piston away from the end of the shaft of the rotor.

[0046] In a method according to an exemplary and non-limiting embodiment, the hydraulic cylinder is a single-acting hydraulic cylinder capable of pushing a hydraulic piston toward the end of the shaft of the rotor, and the force generating device includes a return spring configured to push the hydraulic piston away from the end of the shaft of the rotor.

[0047] A method according to an exemplary and non-limiting embodiment includes maintaining the pressure of a hydraulic fluid by means of a flexible material (eg, air) being compressed and tending to return to an uncompressed state.

[0048] The method according to an exemplary and non-limiting embodiment includes using a protective element between an actuator of a force generating device and an end of a rotor shaft. The protective element is made of a material softer than the material of the rotor shaft (e.g., aluminum or nylon) and protects the rotor shaft from shape deformation.

[0049] The method according to an exemplary and non-limiting embodiment comprises:

[0050] - generating a status signal indicating whether the actuator directs an axial force to the end of the shaft of the rotor;

[0051] - delivering the status signal to a converter configured to drive an electric motor; and

[0052] - when the status signal indicates that the actuator directs the axial force to the end of the shaft of the rotor, disabling the converter from supplying voltage to the electric machine.

[0053] A method according to an exemplary and non-limiting embodiment includes: generating a status signal indicating whether an actuator is directing an axial force to an end of a shaft of a rotor; and generating an alarm in response to: i) the force generating device has been controlled to direct the axial force to the end of the shaft, but ii) the status signal indicates that no axial force is being directed to the end of the shaft.

[0054] The specific examples provided in the description given above should not be construed as limiting the applicability and / or interpretation of the appended claims.It should be noted that, unless expressly stated otherwise, the example lists and example groups given in this document are non-exhaustive lists and groups.

Claims

1. A motor (100, 200), comprising: - stator (101, 201); a rotor (102, 202) rotatably supported relative to the stator and configured to electromagnetically interact with the stator to generate torque in response to one or more currents supplied to the motor; as well as - bearings (103, 203) configured to rotatably support the rotor relative to the stator, Characterized in that the electric machine further comprises a force generating device (104, 204) mechanically attached to the stator and comprising an actuator (105, 205) configured to direct an axial force to the end of the shaft (106, 206) of the rotor to eliminate clearance with the bearings.

2. The motor according to claim 1, wherein The force generating device (104, 204) comprises a hydraulic cylinder (107, 207), and the actuator (105, 205) of the force generating device comprises a hydraulic piston (108, 208).

3. The motor according to claim 2, wherein The hydraulic cylinder (207) is a double-acting hydraulic cylinder capable of pushing the hydraulic piston (208) toward the end of the shaft of the rotor and capable of moving the hydraulic piston away from the end of the shaft of the rotor.

4. The motor according to claim 2, wherein The hydraulic cylinder (107) is a single-acting hydraulic cylinder capable of pushing the hydraulic piston (108) toward the end of the shaft of the rotor, and the force generating device (104) includes a return spring (109) configured to push the hydraulic piston away from the end of the shaft of the rotor.

5. The electric machine according to any one of claims 2 to 4, wherein: The force generating device (104, 204) includes a pressurizer (110, 210, 230) configured to maintain the pressure of the hydraulic fluid by means of a flexible material (111) being compressed and tending to return to an uncompressed state.

6. The electric machine according to any one of claims 2 to 5, wherein: The force generating device (104, 204) includes a collar section (112) attached to a bearing shield (113) of the motor and a flange section (114) connected to the collar section, the hydraulic cylinder (107, 207) is attached to the flange section, and the actuator (105, 205) protrudes through an aperture of the flange section toward the end of the shaft of the rotor.

7. The electric machine according to any one of claims 1 to 6, wherein: The motor includes a protective element (117) between the actuator (105) of the force generating device (104) and the end of the shaft (106) of the rotor, the protective element being made of a material softer than the material of the shaft (106) of the rotor and protecting the shaft of the rotor from shape deformation.

8. The electric machine according to any one of claims 1 to 7, wherein: The electric machine comprises a state detection device (115) configured to generate a state signal (116) indicating whether the actuator (105, 205) directs the axial force to the end of the shaft (106, 206) of the rotor.

9. The motor according to claim 8, wherein The motor includes a control device (150) configured to control the force generating device (104), receive the status signal (116), and generate an alarm in response to: i) the force generating device has been controlled to direct the axial force to the end of the shaft, but ii) the status signal (116) indicates that no axial force is being directed to the end of the shaft.

10. An electric drive, comprising: - an electric motor (100), and - a converter (132) configured to drive the electric motor, wherein the motor (100) is a motor according to claim 8 or 9, and the converter is configured to receive the status signal and to avoid supplying voltage to the motor when the status signal indicates that the actuator directs the axial force to the end of the shaft of the rotor.

11. A method for transporting and supporting a motor, the motor comprising: - stator (101, 201), a rotor (102, 202) rotatably supported relative to the stator and configured to electromagnetically interact with the stator to generate torque in response to current supplied to the motor; as well as - bearings (103, 203) configured to rotatably support the rotor relative to the stator, Characterized in that the method comprises directing (301) an axial force to the end of the shaft (106, 206) of the rotor to eliminate clearance with the bearings, wherein a force generating device (104, 204) is mechanically attached to the stator and comprises an actuator (105, 205) configured to direct the axial force to the end of the shaft of the rotor.

12. The method according to claim 11, wherein The force generating device (104, 204) comprises a hydraulic cylinder (107, 207), and the actuator (105, 205) of the force generating device comprises a hydraulic piston.

13. The method according to claim 12, wherein: The hydraulic cylinder (207) is a double-acting hydraulic cylinder capable of pushing the hydraulic piston (208) toward the end of the shaft of the rotor and capable of moving the hydraulic piston away from the end of the shaft of the rotor.

14. The method according to claim 13, wherein: The hydraulic cylinder (107) is a single-acting hydraulic cylinder capable of pushing the hydraulic piston toward the end of the shaft of the rotor, and the force generating device (104) includes a return spring (109) configured to push the hydraulic piston away from the end of the shaft of the rotor.

15. The method according to any one of claims 12 to 14, wherein The method includes maintaining the pressure of the hydraulic fluid by means of a flexible material (111) being compressed and tending to return to an uncompressed state.

16. The method according to any one of claims 11 to 15, wherein The method includes using a protective element (117) between an actuator (205) of a force generating device (104) and an end of a shaft (106) of the rotor, the protective element being made of a material softer than the material of the shaft (106) of the rotor and protecting the shaft of the rotor from shape deformation.

17. The method according to any one of claims 11 to 16, wherein The method comprises: - generating a status signal (116) indicating whether the actuator (105) directs the axial force to the end of the shaft (106) of the rotor; - delivering the status signal to a converter (132) configured to drive the motor; and When the status signal indicates that the actuator directs the axial force to the end of the shaft of the rotor, the converter is disabled from supplying voltage to the electric machine.

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