Shaft current prevention structure of motor
By adding an insulating layer to the inner layer of the motor bearing sleeve, the problem of motor shaft current damage to the bearing is solved, the maintenance workload and cost are reduced, and it is suitable for a variety of structures, achieving reliable operation of the motor.
Patent Information
- Application Number
- CN202420950056.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-06
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2034-05-06
AI Technical Summary
When preventing motor shaft current, the existing technology has problems such as frequent replacement of grounding carbon brushes, increasing maintenance workload and high cost, as well as long procurement cycle and expensive insulated bearings, which are difficult to effectively prevent the damage to the bearings by shaft current. .
By adding an insulating layer to the inner layer of the bearing sleeve, using an interference-fit insulating sleeve and epoxy glass cloth plate, combined with seamless steel pipes and bonding technology, an insulating bearing sleeve is formed to ensure that the insulating layer does not fall off during the motor assembly, and reduces the Cost and installation complexity.
It effectively prevents the damage to the bearing by shaft current, reduces the maintenance workload, reduces the cost, and is suitable for a variety of structures, including structures without bearing sleeves, and has a wide range of use.
Smart Images
Figure CN222282935U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of design and manufacture of three-phase asynchronous motors, in particular to a motor shaft current protection structure. Background Art
[0002] When the motor shaft voltage exceeds a certain value, it will cause electrical corrosion pits on the inner and outer raceways of the bearings, causing the bearings to fail and seriously affecting the reliable operation of the motor. It is generally believed that motors with a shaft voltage limit of 0.35V and above must take measures to prevent shaft current;
[0003] In the prior art, the technical solutions for preventing shaft current are generally divided into the following two types:
[0004] 1. Install a grounding carbon brush at the shaft end to reduce the shaft potential. The grounding carbon brush is reliably grounded and in reliable contact with the shaft to ensure that the shaft potential is zero, thereby eliminating the shaft current;
[0005] 2. Add an insulating layer to the bearing sleeve at the non-shaft extension end or use an insulating bearing to cut off the shaft current circuit.
[0006] The defects of the prior art are:
[0007] 1. For the method of installing the grounding carbon brush at the shaft end:
[0008] (1) Although it can effectively eliminate shaft current, the carbon brush is in contact with the motor shaft. The carbon brush needs to be replaced in time after being worn, which affects the continuous operation of the motor and increases the user's maintenance workload. Users are not happy with this method.
[0009] (2) The grounding carbon brush in this technical solution tends to be gradually replaced by carbon fiber with extremely low resistivity, wear resistance and low friction resistance; however, although carbon fiber is wear-resistant and does not need to be replaced, it can only guarantee continuous work for about seven years, and the price is relatively high. Users do not know where to buy it, and it is currently difficult to promote its use in large quantities;
[0010] 2. For the method of using insulating bearings to cut off the shaft current circuit:
[0011] (1) The procurement cycle of insulated bearings is long and cannot meet the timely delivery requirements;
[0012] (2) The price of insulated bearings is about three times that of ordinary bearings, which will significantly increase the cost of motor manufacturing and is generally rarely used.
[0013] 3. Method for adding insulation layer to the bearing sleeve at the non-shaft extension end:
[0014] At present, this method has gradually become an important method to prevent shaft current. The method of adding an insulating layer to the bearing sleeve is divided into two types: adding an insulating layer to the outer layer of the bearing sleeve and adding an insulating layer to the inner layer of the bearing sleeve. Manufacturers represented by Jiamusi Motor, Shandong Huali, Wolong Electric, Wuhan Motor, etc. use an insulating layer to add an insulating layer to the outer layer of the bearing sleeve. This method requires the metal hose of the bearing temperature measuring element to be insulated. Otherwise, it is a false method of cutting off the shaft current loop, which is bound to increase costs.
[0015] In summary, the above two types of three methods for preventing shaft current all have shortcomings, and a new bearing assembly technology solution is needed to effectively prevent shaft current from damaging the bearing. Utility Model Content
[0016] In view of the above problems, the utility model provides a motor shaft current protection structure, which aims to prevent shaft current damage to the bearing by adding an insulating layer to the inner layer of a bearing sleeve, a part in the bearing assembly, and prevent the insulating layer added to the inner layer of the bearing sleeve from falling off during motor assembly; the utility model has low cost, is easy to manufacture and install, and has a wide range of uses; it saves users the maintenance workload of replacing carbon brushes; and it is directly applied to casting end covers or steel end covers.
[0017] In order to solve the above problems, the technical solution provided by the utility model is:
[0018] A motor shaft current protection structure comprises an insulating bearing sleeve, an insulating bearing inner cover, and an insulating bearing outer cover; wherein:
[0019] The insulating bearing sleeve comprises a rough-turned bearing sleeve and an insulating sleeve; the insulating sleeve is sleeved in the inner hole of the rough-turned bearing sleeve by interference fit;
[0020] The insulating bearing inner cover comprises a rough-turned bearing inner cover and an insulating plate; the rough-turned bearing inner cover and the insulating plate are bonded together;
[0021] The insulating bearing outer cover comprises a rough-turned bearing outer cover and the insulating plate; the rough-turned bearing outer cover and the insulating plate are bonded together.
[0022] Preferably, the insulating sleeve comprises a sleeve and a non-weft tape; the non-weft tape is wound around the side of the sleeve;
[0023] Preferably, a boss is provided in the middle of the side surface of the sleeve; the boss is annular and 2 mm high, and is used to prevent the non-weft belt from axially loosening.
[0024] Preferably, a circle of ribs are respectively provided at both ends of the sleeve; the height of the ribs is 6 mm.
[0025] Preferably, the sleeve is made of a seamless steel pipe.
[0026] Preferably, the overwinding tension of the non-weft tape wrapped around the side of the sleeve is 1000N.
[0027] Preferably, the insulating board is an epoxy glass cloth board with a thickness of 1 mm.
[0028] Preferably, the rough-turned bearing inner cover and the insulating plate are bonded together using instant adhesive or AB adhesive;
[0029] The rough-turned bearing outer cover and the insulating plate are bonded together by using instant adhesive or AB adhesive.
[0030] Compared with the prior art, the utility model has the following advantages:
[0031] 1. Due to the simple structure of the utility model, compared with the insulating bearing, the cost is low, the manufacturing and installation are convenient, the application range is wide, and the effect is good after being verified by use;
[0032] 2. Since the utility model does not require additional maintenance by the user, it saves the user the maintenance workload of replacing carbon brushes once and for all;
[0033] 3. Since the shaft current protection device of the utility model can also be applied to a structure without a bearing sleeve, it can also be directly applied to the inner diameter of a casting end cover or a steel end cover. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1a A schematic diagram of an anti-axial current bearing assembly according to a specific embodiment of the utility model;
[0035] Figure 1b for Figure 1a A radial cross-sectional view in the vertical direction;
[0036] Figure 2a It is a schematic diagram of a bearing sleeve with an insulating structure in an anti-axial current bearing assembly according to a specific embodiment of the utility model;
[0037] Figure 2b for Figure 2a CC section view;
[0038] Figure 3 A schematic diagram of a bearing sleeve assembly according to a specific embodiment of the utility model;
[0039] Figure 4 A schematic diagram of an insulating sleeve of a specific embodiment of the utility model;
[0040] Figure 5a This is a schematic diagram of a rough turning bearing sleeve of a specific embodiment of the utility model;
[0041] Figure 5b for Figure 5a A radial cross-sectional view of
[0042] Figure 6 It is a schematic diagram of a specific embodiment of the utility model;
[0043] Figure 7a A schematic diagram of a bearing inner cover according to a specific embodiment of the utility model;
[0044] Figure 7b for Figure 7a AA section view;
[0045] Figure 8a This is a schematic diagram of a rough-turned bearing inner cover according to a specific embodiment of the utility model;
[0046] Figure 8b for Figure 8a AA section view;
[0047] Figure 9a A schematic diagram of an insulating plate according to a specific embodiment of the utility model;
[0048] Figure 9b for Figure 9a A radial cross-sectional view of
[0049] Fig.10a A schematic diagram of a bearing outer cover according to a specific embodiment of the utility model;
[0050] Fig.10b for Fig.10a AA section view;
[0051] Fig.10c for Fig.10a BB cross-sectional view;
[0052] Fig.10d for Fig.10a D-direction view;
[0053] Fig.10e for Fig.10a M-direction view;
[0054] Fig.11a This is a schematic diagram of a rough-turned bearing outer cover of a specific embodiment of the utility model;
[0055] Fig.11b for Fig.11a AA section view;
[0056] Fig.11c for Fig.11a BB cross-sectional view.
[0057] Among them: 1. sleeve, 2. non-weft belt, 3. insulating bearing sleeve, 4. rough-turned bearing sleeve, 5. insulating sleeve, 6. boss, 7. rib, 8. rough-turned bearing inner cover, 9. rough-turned bearing outer cover, 10. insulating plate. DETAILED DESCRIPTION
[0058] The present invention is further illustrated below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.
[0059] like Figure 1a to Figure 1b The motor shaft current protection structure shown comprises an insulating bearing sleeve 3, an insulating bearing inner cover, and an insulating bearing outer cover; wherein:
[0060] The insulating bearing sleeve 3 comprises a rough-turned bearing sleeve 4 and an insulating sleeve 5 ; the insulating sleeve 5 is sleeved in the inner hole of the rough-turned bearing sleeve 4 by means of interference fit.
[0061] In this specific embodiment, the insulating sleeve 5 includes a sleeve 1 and a non-weft tape 2 ; the non-weft tape 2 is wound around the side of the sleeve 1 .
[0062] In this specific embodiment, a boss 6 is provided in the middle of the side surface of the sleeve 1; the boss 6 is annular and 2 mm high, and is used to prevent the non-weft belt 2 from axial loosening.
[0063] In this specific embodiment, a circle of ribs 7 is respectively provided at both ends of the sleeve 1; the height of the ribs 7 is 6 mm.
[0064] In this specific embodiment, the sleeve 1 is made of seamless steel pipe.
[0065] In this specific embodiment, the overwinding tension of the non-weft belt 2 wound around the side of the sleeve 1 is 1000N.
[0066] The insulating bearing inner cover comprises a rough-turned bearing inner cover 8 and an insulating plate 10 ; the rough-turned bearing inner cover 8 and the insulating plate 10 are bonded together.
[0067] The insulating bearing outer cover comprises a rough-turned bearing outer cover 9 and an insulating plate 10 ; the rough-turned bearing outer cover 9 and the insulating plate 10 are bonded together.
[0068] In this specific embodiment, the insulating board 10 is an epoxy glass cloth board with a thickness of 1 mm.
[0069] In this specific embodiment, the rough-turned bearing inner cover 8 and the insulating plate 10 are bonded together by using instant adhesive or AB adhesive.
[0070] In this specific embodiment, the rough-turned bearing outer cover 9 and the insulating plate 10 are bonded together by using instant adhesive or AB adhesive.
[0071] In order to further demonstrate the practicality and novelty of the technical solution of the utility model, the manufacturing method of each component of the utility model and the manufacturing method of the entire structure are also included in this specific embodiment as follows:
[0072] The manufacturing method of the insulating bearing sleeve 3 specifically comprises the following steps:
[0073] A100. Figure 5a to Figure 5b As shown, the bearing sleeve is rough-turned until the inner hole meets the required size, thereby obtaining a rough-turned bearing sleeve 4.
[0074] A200. By heating the rough turning bearing sleeve 4, the prepared Figure 4 The insulating sleeve 5 shown is heat-shrunk into the inner hole of the rough-turned bearing sleeve 4 so that the two are interference-fitted and thus fastened.
[0075] It should be noted that if Figure 3 As shown, in A200, due to the temperature difference of 180K between the two, the bearing sleeve assembly can be finally formed.
[0076] A300. Wait for the bearing sleeve assembly to cool to room temperature before performing the final turning step.
[0077] like Figure 4 As shown, the manufacturing method of the insulating sleeve 5 specifically comprises the following steps:
[0078] B100. Figure 6 As shown, the non-weft tape 2 (2843-W) is wound around the sleeve 1 with a pulling force of 1000N to the diameter required by the drawing.
[0079] In this specific embodiment, the model of the non-weft belt 2 is 2843-W.
[0080] B200. Harden the non-weft tape 2 at 150°C for not less than 6 hours.
[0081] B300. After the non-weft tape 2 is hardened, it is processed to the size shown in the drawing to form the insulating sleeve 5.
[0082] It should be noted that the manufacturing method of the insulating sleeve 5 is the core of this technical solution.
[0083] It needs to be further explained that if Figure 6 As shown, the sleeve 1 has 6 mm ribs 7 at both ends during machining; this has two purposes: on the one hand, it is convenient to wind the non-weft tape 2 on the horizontal lathe; on the other hand, a 6 mm metal rib 7 is still left after the outer circle of the insulating sleeve 5 is machined, because it plays a guiding role during heat shrinkage and protects insulation.
[0084] It needs to be further explained that if Figure 6 As shown, a 2 mm high boss 6 is left in the middle of the sleeve 1 during lathe processing to prevent the non-weft belt 2 from axially loosening.
[0085] It needs to be further explained that if Figure 6As shown, sleeve 1 is made of seamless steel pipe, which reduces the processing amount and reduces the cost.
[0086] It needs to be further explained that if Figure 3 As shown, the bearing sleeve assembly is machined as shown in Figure 2a to Figure 2b After the insulating bearing sleeve 3 is installed, the 6 mm metal ribs 7 at both ends will be machined off to expose the insulating layer.
[0087] like Figure 7a to Figure 7b As shown, the manufacturing process of the insulating bearing inner cover specifically includes the following steps:
[0088] C100. Figure 8a to Figure 8b As shown, according to the design drawing, the bearing inner cover 8 is rough-turned.
[0089] C200. Roughen the joint surface of the bearing inner cover after rough turning with sandpaper; then clean it with acetone.
[0090] C300. Use Loctite 406 or two-component AB resin to Figure 9a to Figure 9b The insulating plate 10 shown is bonded to the rough-turned bearing inner cover 8 .
[0091] C400. After bonding, store at room temperature for 24 hours to allow the Loctite glue or two-component AB resin to fully cure.
[0092] C500. Figure 7a to Figure 7b As shown, after the Loctite glue or two-component AB resin is completely cured, the final processing is carried out to form the insulating bearing inner cover.
[0093] It should be noted that after the turning process is completed, the epoxy glass cloth board is sawed off along the two sides of the oil grooves at the four oil grooves.
[0094] It should be further explained that Loctite 406 is an instant adhesive and should be bonded immediately after application.
[0095] It should be further noted that, whenever possible, two-component AB resins should be preferred to achieve better mechanical properties.
[0096] like Figure 10a to Figure 10e As shown, the manufacturing process of the insulating bearing outer cover specifically includes the following steps:
[0097] D100. Figure 11a to Figure 11c As shown, according to the design drawing, the bearing outer cover 9 is rough-turned.
[0098] D200. Roughen the joint surface of the bearing outer cover after rough turning with sandpaper; then clean it with acetone.
[0099] D300. Use Loctite 406 or two-component AB resin to Figure 9a to Figure 9bThe insulating plate 10 shown is bonded to the rough-turned bearing cover 9 .
[0100] D400. After bonding, store at room temperature for 24 hours to allow the Loctite glue or two-component AB resin to fully cure.
[0101] D500. Figure 10a to Figure 10e As shown, after the Loctite glue or two-component AB resin is completely cured, the final processing is carried out to form an insulating bearing outer cover.
[0102] It should be noted that Loctite 406 is an instant adhesive and should be bonded immediately after application.
[0103] It should be further noted that, whenever possible, two-component AB resins should be preferred to achieve better mechanical properties.
[0104] In order to further verify the practicality of the utility model, the insulation performance of the specific embodiment is also tested after the above manufacturing process is completed. The insulation resistance of the insulating bearing sleeve 3, the insulating bearing inner cover, and the insulating bearing outer cover is measured using a 500V megohmmeter. The insulation resistance is above 1MΩ to meet the insulation requirements. In actual production, the insulation resistance is generally above 500MΩ, which meets the design requirements.
[0105] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than those clearly stated in each claim. On the contrary, as reflected in the attached claims, the utility model is in a state with less than all the features of the disclosed individual embodiments. Therefore, the attached claims are hereby expressly incorporated into the detailed description, with each claim acting alone as a separate preferred embodiment of the utility model.
[0106] The disclosed embodiments are described above to enable any person skilled in the art to implement or use the present invention. Various modifications of these embodiments are obvious to those skilled in the art, and the general principles defined herein may also be applied to other embodiments without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in the present application.
[0107] The above description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".
[0108] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above description is only the specific implementation method of the utility model and is not used to limit the protection scope of the utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.
Claims
1. A motor shaft current protection structure, characterized in that: It comprises an insulating bearing sleeve (3), an insulating bearing inner cover, and an insulating bearing outer cover; wherein: The insulating bearing sleeve (3) comprises a rough-turned bearing sleeve (4) and an insulating sleeve (5); the insulating sleeve (5) is sleeved in the inner hole of the rough-turned bearing sleeve (4) by means of interference fit; The insulating bearing inner cover comprises a rough-turned bearing inner cover (8) and an insulating plate (10); the rough-turned bearing inner cover (8) and the insulating plate (10) are bonded together; The insulating bearing outer cover comprises a rough-turned bearing outer cover (9) and the insulating plate (10); the rough-turned bearing outer cover (9) and the insulating plate (10) are bonded together.
2. The motor shaft current protection structure according to claim 1, characterized in that: The insulating sleeve (5) comprises a sleeve (1) and a non-weft belt (2); the non-weft belt (2) is wound around the side of the sleeve (1).
3. The motor shaft current protection structure according to claim 2 is characterized in that: A boss (6) is provided in the middle of the side surface of the sleeve (1); the boss (6) is annular and 2 mm high and is used to prevent the non-weft belt (2) from axial loosening.
4. The motor shaft current protection structure according to claim 3 is characterized in that: A circle of retaining edge (7) is respectively provided at both ends of the sleeve (1); the height of the retaining edge (7) is 6 mm.
5. The motor shaft current protection structure according to claim 4 is characterized in that: The sleeve (1) is made from a seamless steel pipe.
6. The motor shaft current protection structure according to claim 5, characterized in that: The overwinding tension of the non-weft belt (2) wound around the side of the sleeve (1) is 1000N.
7. The motor shaft current protection structure according to claim 6, characterized in that: The insulating board (10) is an epoxy glass cloth board with a thickness of 1 mm.
8. The motor shaft current protection structure according to claim 7, characterized in that: The rough-turned bearing inner cover (8) and the insulating plate (10) are bonded together using instant adhesive or AB adhesive; The rough-turned bearing outer cover (9) and the insulating plate (10) are bonded together using instant adhesive or AB adhesive.