A high-precision potting sine-cosine resolver and a processing method thereof

Abstract

The application discloses a kind of potting high-precision sine-cosine rotary transformer and processing method, it is related to the field of sine-cosine rotary transformer processing applied to extreme environment, including to rotor is potting and solidification, the part of potting material is potting outside rotor support, obtains rotor potting piece;Potting and solidification are carried out to stator, the part of potting material is potting inside annular transformer primary side core, obtains stator potting piece;The outer cylindrical surface of rotor potting piece is ground, and the inner cylindrical surface of stator potting piece is ground.Rotary transformer functional components are sealed tightly, greatly broaden the rotary transformer work field, improve the ability of rotary transformer to resist hydraulic oil, damp, mould and other harsh environments, improve explosion-proof reliability.

Description

Technical Field

[0001] This invention relates to a sine and cosine rotary transformer for measuring mechanical rotation angles, applicable to extreme environments such as oil pressure resistance, dust prevention, mildew prevention, salt spray prevention, and explosion prevention. Background Technology

[0002] A resolver, or simply resolver, is an induction-type micromotor whose output voltage maintains a certain functional relationship with the rotor angle. A typical application of resolvers is in conjunction with servo motors to detect the rotor position in real time, enabling high-precision control of motor speed, torque, and other performance parameters; they are also used in other applications requiring precise measurement of rotation angles.

[0003] With the expansion of applications for resolvers, the special requirements such as miniaturization and strong environmental resistance cannot be met by conventional resolvers. Furthermore, as resolvers are mass-produced products, the complex and delicate winding of the coils should be done manually as much as possible. Therefore, there is an urgent need to develop potted high-precision resolvers suitable for mechanized and automated production.

[0004] Currently, improving the environmental resistance of rotary transformers relies on potting and sealing structure design. The only relevant patent found for "potted rotary transformers" is CN106298217B, a potting device, method, and application of a rotary transformer from Zhuzhou CRRC Electromechanical Technology Co., Ltd. This patent focuses on reluctance rotary transformers and primarily proposes innovative points and rights protection for the potting device, method, and application of rotary transformers. This patent only pots the stator of the rotary transformer, as its windings are all on the stator side; the rotor side has no windings and does not require potting.

[0005] Among the retrievable patents related to "sine and cosine rotary transformers," the sealing structure of an oil-immersed sine and cosine rotary transformer from Beijing Shuguang Aviation Electrical Co., Ltd. (patent number: CN218768946U) and the high-voltage sealed sine and cosine rotary transformer from Shaanxi Dongfang Aviation Instrument Co., Ltd. (patent number: CN217544296U) are related to oil immersion and sealing. However, the main method of both is to seal the rotary transformer in a shell. Structurally, this increases the overall size of the transformer due to the addition of the shell and other related structures, limiting its application in space-constrained conditions. In terms of manufacturing, additional docking interfaces need to be added to the shell, complicating the structure. Summary of the Invention

[0006] The technical problem solved by this application is to overcome the shortcomings of the prior art and provide a structure in which both the stator and rotor of a sine and cosine rotary transformer are encapsulated, so as to solve the problem of low environmental resistance of sine and cosine rotary transformers in the prior art, making the rotary transformer products suitable for extreme environments such as oil pressure resistance, dust prevention, mildew prevention, salt spray, and explosion prevention.

[0007] Secondly, the technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a structure with higher roundness and roughness requirements for the inner circle of the stator and the outer circle of the rotor of a sine and cosine rotary transformer, so as to solve the problems of large electrical error (greater than 10 arcminutes) and low batch pass rate of sine and cosine rotary transformers in the prior art.

[0008] The technical solution provided in this application is as follows:

[0009] A method for processing a potted high-precision sine / cosine rotary transformer is disclosed. The sine / cosine rotary transformer includes a rotor and a stator sleeved around the rotor. The rotor includes a rotor support, and a primary core, a primary winding, a secondary core, and a secondary winding of the rotary transformer disposed outside the rotor support. The stator includes a primary core, and a primary winding, a secondary core, and a secondary winding of the rotary transformer disposed inside the primary core. The processing method includes:

[0010] The rotor is potted and cured, and the potting material is used to pot the outer part of the rotor support to obtain the rotor potting component; the stator is potted and cured, and the potting material is used to pot the inner part of the primary iron core of the toroidal transformer to obtain the stator potting component.

[0011] The outer cylindrical surface of the rotor potting component is ground, and the grinding dimension is the grinding allowance. The inner cylindrical surface of the stator potting component is ground.

[0012] The process of potting and curing the rotor includes: placing the rotor on a first potting fixture, the top of which has a first annular groove, and a first positioning post formed in the middle of the first annular groove. The inner diameter of the rotor bracket matches the outer diameter of the first positioning post so that the rotor is sleeved outside the first positioning post and located inside the first annular groove. The outer diameter of the first annular groove is larger than the outer diameter of the rotor.

[0013] The first potting fixture has an annular accommodating groove at the bottom of the first annular groove near the first positioning post. The depth of the accommodating groove is consistent with the height of the rotor support end protruding from the end of the secondary iron core of the annular transformer.

[0014] The process of potting and curing the stator includes: placing the stator on a second potting fixture, the top of which is provided with a second annular groove, and a second positioning post formed in the middle of the second annular groove. The outer diameter of the primary iron core of the toroidal transformer matches the outer diameter of the second annular groove so that the stator is fitted inside the second annular groove and fits against the inner wall of the second annular groove. The outer diameter of the second positioning post is smaller than the inner diameter of the stator.

[0015] The dimensions of the primary and secondary cores of the rotary transformer before grinding are the design dimensions plus the grinding allowance. The design dimensions are the dimensions of the primary and secondary cores of the rotary transformer after grinding.

[0016] It also includes grinding the two ends of the rotor potting component and the stator potting component. The two ends of the rotor potting component and the stator potting component are the mechanical interface mounting surfaces to ensure the accuracy of the mechanical interface mounting surfaces.

[0017] A potted high-precision sine and cosine rotary transformer is obtained according to any of the above-described processing methods for a potted high-precision sine and cosine rotary transformer.

[0018] In summary, this application includes at least the following beneficial technical effects:

[0019] 1. The sine and cosine rotary transformer stator and rotor potting method proposed in this invention is designed for rotary transformer products with windings on both the stator and rotor sides. It tightly seals all the functional components of the rotary transformer (i.e., the stator and rotor sides), greatly expanding the working field of the rotary transformer, improving its ability to withstand harsh environments such as hydraulic oil, humidity, and mold, and enhancing its explosion-proof reliability. Moreover, the method proposed in this invention achieves excellent potting for rotary transformer products with small structures and high potting operation difficulty.

[0020] 2. The sine and cosine rotary transformer stator and rotor inner and outer cylindrical grinding (including the allowance design before grinding) proposed in this invention improves the magnetic field distortion caused by the lamination structure of some iron cores of the rotary transformer, thereby improving the electrical error accuracy and batch pass rate of the rotary transformer; at the same time, the improvement of the accuracy of the rotary transformer also means that the rotary transformer can be applied to fields with higher precision requirements.

[0021] 3. The potting and grinding of the sine and cosine rotary transformer proposed in this invention does not change the original mechanical and electrical interfaces of the rotary transformer, and can achieve in-situ replacement with the non-potted rotary transformer, but its working accuracy and reliability are significantly improved. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the basic structure of a sine / cosine rotary transformer according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the integral potting of the rotor of a sine / cosine rotary transformer according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the grinding process of the encapsulation layer of the sine and cosine rotary transformer rotor according to an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the overall potting of the stator of a sine / cosine rotary transformer according to an embodiment of the present invention;

[0026] Figure 5This is a schematic diagram of the grinding process of the stator encapsulation layer of a sine / cosine rotary transformer according to an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures: 1. Rotor support; 2. Primary core of toroidal transformer; 3. Secondary core of toroidal transformer; 4. Primary winding of toroidal transformer; 5. Secondary winding of toroidal transformer; 6. Primary core of rotary transformer; 7. Secondary core of rotary transformer; 8. Primary excitation winding and compensation winding of rotary transformer; 9. Secondary winding of rotary transformer. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

[0029] This application discloses a potted high-precision sine and cosine rotary transformer. Taking a small sine and cosine rotary transformer with an outer diameter of 20mm, a rotor mounting diameter of 4mm, and a total length of 18mm as an example, a high thermal conductivity epoxy potting compound is selected as the potting material.

[0030] The basic structure and working principle of a sine / cosine rotary transformer are as follows:

[0031] A sine / cosine rotary transformer functionally consists of two parts: a toroidal transformer and a rotary transformer, as shown in the appendix. Figure 1 In the diagram, 1 is the rotor support, used to support and connect the rotating parts of the sine and cosine rotary transformers (the rotating parts include the secondary core 3 of the toroidal transformer and the primary core 6 of the rotary transformer); 2 is the primary core of the toroidal transformer, which also serves as the stator housing; 3 is the secondary core of the toroidal transformer; 4 is the primary winding of the toroidal transformer; 5 is the secondary winding of the toroidal transformer; 6 is the primary core of the rotary transformer; 7 is the secondary core of the rotary transformer; 8 is the primary winding of the rotary transformer (or the excitation winding and the compensation winding); 9 is the secondary winding of the rotary transformer (or the sine winding and the cosine winding). The primary core 6 and the secondary core 7 of the rotary transformer are composed of multiple toroidal laminations.

[0032] The rotor support 1 is cylindrical in shape. Multiple laminations of the primary core 6 of the rotary transformer are sequentially fitted onto the rotor support 1 and connected to it. The primary core 6 of the rotary transformer has a slotted structure for winding the primary winding 8. The secondary core 3 of the toroidal transformer is fitted onto the outside of the rotor support 1 and located at one end of the primary core 6. The outer side of the secondary core 3 has an annular groove along its circumference, and the secondary winding 5 of the toroidal transformer is wound within the outer annular groove. The rotor support 1, along with the primary core 6, primary winding 8, secondary core 3, and secondary winding 5 of the toroidal transformer mounted on the outside of the rotor support 1, constitute the rotor. The primary core 2 of the toroidal transformer is sleeved on the outside of the rotor support 1. An inner annular groove is provided on the inner side of the primary core 2, and the primary winding 4 of the toroidal transformer is disposed within this groove. The primary winding 4 is opposite to the secondary winding 5. The secondary core 7 of the rotary transformer is installed inside the primary core 2 and has a slotted structure for winding the secondary winding 9. The secondary core 7 is directly opposite the primary core 6. The primary core 2, along with the primary winding 4, secondary core 7, and secondary winding 9 installed inside the primary core 2, constitute the stator.

[0033] The coupling relationship between the primary and secondary sides of a toroidal transformer does not change with rotor rotation, allowing for stable transmission of the primary AC voltage signal to the secondary side. The secondary winding of the toroidal transformer is electrically connected to the primary winding of the resolver, providing power to the latter by generating an excitation current in the primary winding. The primary winding of the resolver is wound on the core with specific turns combinations and arrangements. The core is slotted, and under the influence of the excitation current, a pulsating magnetic field is generated on the surface of the resolver rotor core, coupling to the secondary side of the resolver in real time. The secondary core of the resolver is also correspondingly slotted, and two sets of output signal windings are wound with specific turns combinations and arrangements, and these two sets of windings are orthogonal to each other. Accurate rotor position is calculated by analyzing the voltage amplitude and phase information of the two signal windings. In addition, there is a resolver compensation winding, orthogonally wound to the resolver excitation winding, used to compensate for the distortion of the primary pulsating magnetic field caused by the secondary current of the resolver.

[0034] The insulation design of sine and cosine rotary transformers includes:

[0035] The sine and cosine rotary transformer has six windings: primary winding 4 of the toroidal transformer, secondary winding 5 of the toroidal transformer, primary winding 8 of the rotary transformer (including the excitation winding and the compensation winding), and secondary winding 9 of the rotary transformer (including the sine winding and the cosine winding), each wound on its corresponding iron core. Before the rotary transformer is encapsulated, its electrical insulation must be designed.

[0036] 1) The primary winding of the toroidal transformer, the sine winding and the cosine winding of the rotary transformer are wound on a non-metallic insulating frame and have no contact with metallic materials;

[0037] 2) Due to space constraints, the secondary winding of the toroidal transformer, the excitation winding of the rotary transformer, and the compensation winding are directly wound on a metallic magnetic material. Before winding, the secondary core of the toroidal transformer and the primary core of the rotary transformer are coated with a non-metallic material to form a dense insulating layer.

[0038] 3) After the above 6 sets of windings are completed, non-metallic impregnated materials shall be used for insulation protection.

[0039] Encapsulation design for sine and cosine rotary transformers includes:

[0040] After the resolver was designed and assembled according to the basic structure, working principle, and insulation design of the sine and cosine rotary transformers described above, it is ready for conventional use. Based on this, the stator and rotor of the resolver were respectively potted and subjected to related grinding work, as shown in the attached figure. Figures 2-5 As shown.

[0041] like Figure 2 As shown, the rotor is mounted on a first potting fixture. The top of the first potting fixture has a first annular groove, and a first positioning post is formed in the middle of the first annular groove. The inner diameter of the rotor bracket 1 matches the outer diameter of the first positioning post, so that the rotor is fitted outside the first positioning post and located within the first annular groove. The outer diameter of the first annular groove is larger than the outer diameter of the rotor, so that the outer surface of the rotor has machining allowance after curing. The first potting fixture has an annular receiving groove at the bottom of the first annular groove near the first positioning post. The depth of the receiving groove is consistent with the height of the rotor bracket 1 protruding from the end of the annular transformer secondary core 3, so that the end of the rotor bracket 1 is located within the receiving groove. (Regarding the rotor bracket...) Figure 1 The part other than that shown in Figure 1 is potted. The potting material is injected from the top and covers the potting part (i.e., the rotor). Then, according to the requirements of the potting material, a certain temperature and vacuum are maintained so that the potting material fills the potting part evenly until it is cured.

[0042] As attached Figure 4 As shown, the stator is mounted on the second potting fixture. The top of the second potting fixture has a second annular groove, and a second positioning post is formed in the middle of the second annular groove. The outer diameter of the primary core 2 of the toroidal transformer matches the outer diameter of the second annular groove, so that the stator is fitted inside the second annular groove and fits against the inner wall of the groove. The outer diameter of the second positioning post is smaller than the inner diameter of the stator, so that the inner surface of the stator has machining allowance after curing. For the stator ( Figure 1The part inside (as shown in Figure 2) is potted. The potting material is injected from the top and covers the potting part (i.e., the stator). Then, according to the requirements of the potting material, a certain temperature and vacuum are maintained so that the potting material fills the potting part evenly until it is cured.

[0043] like Figure 3 As shown, after the rotor is potted and cured according to the requirements of the potting material, the shape of the potting layer should be ground. The grinding surfaces are the outer cylindrical surface and both ends of the potting layer. Specifically, the two ends of the potting layer are ground, as shown in the figure with dimensions of 0.1mm and 0.6mm, which are the heights of the protrusions of the secondary iron core 3 of the toroidal transformer and the primary winding 8 of the rotary transformer at both ends of the rotor support 1, respectively. This removes excess potting material attached to the mechanical interface mounting surface without affecting the rotor's accuracy and reliability. The cylindrical surface of the potting layer is ground, as shown in the figure with dimension Φ12. In addition to ensuring the accuracy requirements, i.e., without affecting the rotor's rotation, the roundness and surface roughness are also required, which are generally ensured by the precision of a grinding machine or lathe.

[0044] As attached Figure 5 As shown, after the stator is potted and cured according to the requirements of the potting compound, the shape of the potting layer should be ground. The grinding surfaces are the inner cylindrical surface and both ends of the potting layer. Specifically, the two ends of the potting layer are ground, as shown in dimension 18 in the figure, to remove excess potting compound adhering to the mechanical interface mounting surface without affecting the stator's accuracy and reliability. The inner cylindrical surface of the potting layer is ground, as shown in dimension Φ12.5 in the figure. In addition to ensuring accuracy requirements, i.e., not interfering with the rotor, its roundness and surface roughness are also required, which are generally ensured by the precision of a grinding machine or lathe.

[0045] Finally, check the potting quality of the stator and rotor. The surface should be uniform and smooth, without cracks or slag, and it should be able to withstand a certain hydraulic pressure of 3-50MPa without cracking or deformation.

[0046] Traditional rotary transformer primary and secondary cores (with) Figure 1 As shown in Figures 6 and 7, the core is made of stacked silicon steel sheets. The outer surface of the primary core and the inner surface of the secondary core are irregular cylindrical surfaces. The magnetic field distortion caused by this irregularity cannot be calculated, which has a significant impact on the overall electrical error of the resolver. Often, in a batch of resolver products, the pass rate for products meeting the accuracy requirements, taking 10 arcminutes as an example, is less than 20%.

[0047] This invention grinds the cylindrical surfaces of the stator and rotor encapsulation layers of a sine / cosine rotary transformer, and also grinds the primary and secondary cores of both the toroidal transformer and rotary transformer sections, as shown in the attached figure. Figure 3 , 5As shown in the diagram, this method significantly improves the roundness of the inner and outer cores of the primary and secondary sides of the rotary transformer, reducing magnetic field distortion caused by the lamination structure, thereby improving the overall accuracy and yield of the rotary transformer. Taking 10 arcminutes as an example, the batch yield reaches over 95%. Under the processing method of this patent, the accuracy and yield of sine and cosine rotary transformers are improved.

[0048] Two points need further explanation: 1) To avoid increasing the overall working air gap of the resolver, the corresponding iron core should have a grinding allowance in the initial design to ensure that the relevant dimensions still meet the requirements after grinding, as shown in the attached figure. Figure 3 Φ12 and attached Figure 5 1) Φ12.5; 2) Conventionally used sine and cosine rotary transformers (without potting) can also be ground to improve the accuracy level and batch pass rate.

[0049] The contents not described in detail in this application specification are common knowledge to those skilled in the art.

[0050] The present application has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.

Claims

1. A method for manufacturing a potted high-precision sine / cosine rotary transformer, characterized in that, Used for processing sine and cosine rotary transformers, the sine and cosine rotary transformers include a rotor and a stator sleeved outside the rotor. The rotor includes a rotor support (1), and a rotary transformer primary core (6), a rotary transformer primary winding (8), a toroidal transformer secondary core (3) and a toroidal transformer secondary winding (5) disposed outside the rotor support (1). The stator includes a toroidal transformer primary core (2), and a toroidal transformer primary winding (4), a rotary transformer secondary core (7) and a rotary transformer secondary winding (9) disposed inside the toroidal transformer primary core (2). Processing methods include: The rotor is potted and cured, and the potting material is used to pot the outer part of the rotor support (1) to obtain the rotor potting part; the stator is potted and cured, and the potting material is used to pot the inner part of the primary iron core (2) of the toroidal transformer to obtain the stator potting part; The outer cylindrical surface of the rotor potting component is ground, and the grinding dimension is the grinding allowance. The inner cylindrical surface of the stator potting component is ground. The process of potting and curing the rotor includes: placing the rotor on a first potting fixture, the top of the first potting fixture having a first annular groove, the middle of the first annular groove forming a first positioning post, the inner diameter of the rotor bracket (1) matching the outer diameter of the first positioning post, so that the rotor is sleeved outside the first positioning post and located inside the first annular groove, the outer diameter of the first annular groove being larger than the outer diameter of the rotor. The process of potting and curing the stator includes: placing the stator on a second potting fixture, the top of which is provided with a second annular groove, and a second positioning post formed in the middle of the second annular groove. The outer diameter of the primary iron core (2) of the annular transformer is matched with the outer diameter of the second annular groove so that the stator is fitted inside the second annular groove and fits against the inner wall of the second annular groove. The outer diameter of the second positioning post is smaller than the inner diameter of the stator.

2. The method for processing a potted high-precision sine / cosine rotary transformer according to claim 1, characterized in that, The first potting fixture has an annular accommodating groove at the bottom of the first annular groove near the first positioning post. The depth of the accommodating groove is consistent with the height of the rotor support (1) protruding from the end of the annular transformer secondary core (3).

3. The method for processing a potted high-precision sine / cosine rotary transformer according to claim 1, characterized in that: The dimensions of the primary core (6) and secondary core (7) of the rotary transformer before grinding are the design dimensions plus the grinding allowance. The design dimensions are the dimensions of the primary core (6) and secondary core (7) of the rotary transformer after grinding.

4. The method for processing a potted high-precision sine / cosine rotary transformer according to claim 1, characterized in that: It also includes grinding the two ends of the rotor potting component and the stator potting component, the two ends of which are the mechanical interface mounting surfaces, to ensure the accuracy of the mechanical interface mounting surfaces.

5. A potted high-precision sine / cosine rotary transformer, characterized in that: The method for processing a potted high-precision sine and cosine rotary transformer according to any one of claims 1-4 is obtained.

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