Motor signal magnetic ring and processing method thereof

Abstract

A motor signal magnet ring and a processing method thereof belong to the technical field of motor sensors, the motor signal magnet ring comprises a magnet ring support and a magnet ring body, the magnet ring support is matched with a rotating shaft, and the magnet ring support is provided with a limiting structure to prevent the magnet ring body from falling off. The magnetic ring support is provided with a sleeving section matched with a motor rotating shaft and a notch used for positioning during manufacturing and magnetizing, the sleeving section of the magnetic ring support and the magnetic ring body are spaced by a gap of 0.1-15 mm in the radial direction, and the number of magnetizing pole pairs of the magnetic ring body is not smaller than 2. The problem that cracks are generated due to the fact that the magnetic ring is subjected to certain mechanical stress or expansion coefficients are inconsistent when the temperature changes sharply during installation can be solved, the vibration and impact resistance is high, and the product reliability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of motor sensors, and in particular to a motor signal magnetic ring and a processing method thereof. Background Art

[0002] In the application of motors, position sensors are required in some application scenarios that require precise control. The main function of position sensors is to provide position signals. When the motor is started or working, the position of the rotor is detected by the sensor, and then a position signal is provided to the driver. After receiving the signal, the driver turns on the drive MOS tube according to a certain logical relationship to realize the drive, speed regulation and position control of the motor.

[0003] In the automotive industry, magnetoresistive sensors have been widely used in automotive motors and industrial motors due to their simple structure, low cost, and integration on PCBA. The commonly used structure is that the signal magnet is installed at the shaft end. The disadvantage of this structure is that it takes up a large axial space and is not conducive to online detection during the product manufacturing process. In some highly integrated products, due to the large space occupied, it is not convenient to arrange and install. Therefore, the demand for designing the disk into a hollow magnetic ring is becoming more and more urgent.

[0004] Since the currently commonly used signal magnetic ring structure has an interference fit with the motor shaft, and the expansion coefficient of the magnetic ring structure is inconsistent when it is subjected to force or heat, there is a risk that the magnetic ring will break and fall off, shortening its service life. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a motor signal magnetic ring and a processing method thereof. The signal magnetic ring has a simple structure and low processing cost. It can avoid cracks caused by inconsistent expansion coefficients when the magnetic ring is subjected to certain mechanical stresses during installation or when the temperature changes drastically. It has strong resistance to vibration and impact and high product reliability.

[0006] To achieve the above purpose, the technical solution adopted by the present invention to solve the technical problem is:

[0007] A motor signal magnetic ring comprises a magnetic ring bracket and a magnetic ring body. The magnetic ring bracket cooperates with a rotating shaft. The magnetic ring bracket is provided with a limiting structure to prevent the magnetic ring body from falling off. The magnetic ring bracket is provided with a sleeve section that cooperates with the motor rotating shaft and a recess for positioning during manufacturing and magnetization. The sleeve section of the magnetic ring bracket and the magnetic ring body are radially separated by a gap of 0.1 to 15 mm, and the number of magnetized pole pairs of the magnetic ring body is not less than 2.

[0008] The limiting structure comprises a flange plate arranged on the outer periphery of the sleeve section, and the aperture of the positioning hole on the flange plate is smaller than that of the other end at one end close to the magnetic ring body or is set as a countersunk hole.

[0009] The limiting structure comprises an annular boss arranged on the outer periphery of the sleeve section, and a limiting recess or protrusion is provided on the annular boss.

[0010] The magnetic ring bracket is interference fit with the motor shaft, and the fitting surface is set to be a smooth surface.

[0011] The magnetic ring bracket is glued to the motor shaft, and a glue storage groove is arranged on the matching surface.

[0012] A method for processing a motor signal magnetic ring comprises the following steps:

[0013] Step 1: stamping and stretching of the magnetic ring bracket;

[0014] Step 2: The magnetic ring bracket is placed in the injection mold as an insert, and the magnetic ring body is injection molded;

[0015] Step 3: Cool and shape before demoulding.

[0016] The beneficial effects of the present invention are:

[0017] 1. The present invention provides a signal magnetic ring including a magnetic ring bracket and a magnetic ring body. The magnetic ring has a hollow structure and does not need to occupy a large axial space. It is easy to install, which broadens the application scenarios of the product, is more conducive to high product integration, and reduces the overall volume of the system. Moreover, the magnetic ring body and the magnetic ring bracket sleeve section are separated by a gap in the radial direction, which avoids the signal magnetic ring from being subjected to certain mechanical stress during installation or cracks caused by inconsistent expansion coefficients when the temperature changes sharply, thereby increasing the reliability of the product and reducing the risk of product failure.

[0018] 2. The present invention connects the magnetic ring body and the magnetic ring bracket through a limiting structure, and the limiting structure is axial and radial limiting, so that after the magnetic ring body is injection molded, it is firmly matched with the magnetic ring bracket, avoiding the axial and radial shaking of the magnetic ring body and improving the vibration and impact resistance of the product.

[0019] 3. The stamping and stretching forming of the magnetic ring bracket in the present invention reduces the manufacturing cost compared with the traditional machining forming method; the present invention provides a notch on the magnetic ring bracket, which can be positioned during manufacturing and magnetization, thereby improving the consistency of the product; the present invention improves the accuracy of the sensor by adopting a multi-pole magnetization method, thereby improving the control accuracy of the control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0021] Figure 1 is a full cross-sectional view of Embodiment 1 of the motor signal magnetic ring of the present invention;

[0022] Figure 2 yes Figure 1 Left view of

[0023] Figure 3 is a full cross-sectional view of a second embodiment of a motor signal magnetic ring of the present invention;

[0024] Figure 4 yes Figure 3 Left view of

[0025] The markings in the above figures are: 1. magnetic ring bracket, 11. sleeve section, 12. flange, 121. positioning hole, 13. annular boss, 131. limiting notch, 14. notch, 2. magnetic ring body. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0027] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions 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 device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] The present invention provides a motor signal magnetic ring and a processing method thereof, which will be specifically described in the following embodiments.

[0030] Embodiment 1

[0031] like Figure 1 and Figure 2As shown, the present invention provides a motor signal magnetic ring, including a magnetic ring bracket 1 installed on the motor shaft and an injection-molded magnetic ring body 2. The installation is convenient, and no large axial space is required, which broadens the application scenarios of the product, is more conducive to high product integration, and reduces the overall volume of the system; and the magnetic ring body 2 and the magnetic ring bracket 1 are radially separated by a distance, and the gap is 0.1 to 15 mm, which can not only ensure the structural strength and stability of the entire signal magnetic ring, but also avoid the signal magnetic ring being subjected to certain mechanical stress during installation or the expansion coefficient is inconsistent when the temperature changes sharply, thereby increasing the reliability of the product and reducing the risk of product failure.

[0032] Specifically, the magnetic ring bracket 1 is formed by stamping and stretching an annular metal part. Compared with the traditional machining forming method, the stamping and stretching forming method reduces the manufacturing cost.

[0033] Specifically, the magnetic ring body 2 is connected to the magnetic ring bracket 1 via a limiting structure, so that after the magnetic ring body 2 is injection molded, it is firmly matched with the magnetic ring bracket 1 to improve the vibration and impact resistance of the product.

[0034] The magnetic ring bracket 1 includes a sleeve section 11 installed on the motor shaft, the magnetic ring body 2 is sleeved outside the sleeve section 11, and the outer wall of the sleeve section 11 and the inner wall of the magnetic ring body 2 are radially separated by a distance, reserving space for the expansion and deformation of the magnetic ring bracket 1; the outer periphery of the sleeve section 11 is connected to the magnetic ring body 2 in the axial and radial directions through a limiting structure, avoiding the axial and radial shaking of the magnetic ring body 2 and improving the vibration and impact resistance of the product.

[0035] The limiting structure includes a flange 12 vertically arranged on the outer periphery of the sleeve section 11. The diameter of the positioning hole 121 at one end close to the magnetic ring body 2 is smaller than that at the other end.

[0036] Since the magnetic ring body 2 is formed on the periphery of the magnetic ring bracket 1 by injection molding, by setting a conical positioning hole 121, during the injection process, the magnetic material fills the positioning hole 121. After cooling and molding, the magnetic ring body 2 cannot shake in the axial and radial directions, and will not separate from the magnetic ring bracket 1. It is firmly matched with the magnetic ring bracket 1, thereby realizing the axial and radial limitation of the magnetic ring body 2 and improving the vibration and impact resistance of the product.

[0037] In addition, a notch 14 for positioning during manufacturing and magnetization is provided on the outer side of the magnetic ring bracket 1, which serves as a unified positioning reference during manufacturing and magnetization, thereby improving the consistency of the product.

[0038] The magnetic ring bracket 1 and the motor shaft can be connected by interference fit or gluing. When interference fit is adopted, the mating surface between the magnetic ring bracket 1 and the shaft is set to be a smooth surface. When gluing is adopted, in order to improve the firmness of the installation, the magnetic ring bracket 1 is provided with a plurality of glue storage grooves (not shown in the figure) at intervals along the circumferential direction on the mating surface. After glue is poured into the glue storage grooves, it is convenient and smooth to install on the motor shaft, thereby realizing circumferential multi-point positioning between the signal magnetic ring and the motor shaft, and the glue overflowing from the glue storage grooves can further improve the firmness of the connection between the signal magnetic ring and the motor shaft.

[0039] The number of magnetized pole pairs on the magnetic ring body 2 is not less than 2. By adopting a multi-pole magnetization method, the accuracy of the sensor is improved, thereby improving the control accuracy of the control system.

[0040] The method for processing the motor signal magnetic ring comprises the following steps:

[0041] Step 1: The magnetic ring bracket 1 is formed by stamping and stretching. The annular metal part is placed on a stamping and stretching machine for stamping and stretching to form a sleeve section 11 and a flange 12 that are perpendicular to each other; and conical positioning holes 121 are punched at intervals in the circumferential direction of the flange 12.

[0042] Step 2: The magnetic ring body 2 is injection molded on the periphery of the magnetic ring bracket 1.

[0043] 1) Place the molded magnetic ring bracket 1 into an injection mold; 2) The mold cavity of the injection mold is set to be annular, so that the flange 12 of the magnetic ring bracket 1 faces downward, and one end of the positioning hole 121 of the flange 12 is sealed, so that the inner side of the injection mold is close to the outer periphery of the magnetic ring bracket 1, and ensure that the radial gap between the magnetic ring body 2 and the magnetic ring bracket 1 in the molded signal magnetic ring is consistent with the thickness of the injection mold; 3) The magnetic material is injected into the mold cavity of the mold by an injection molding machine at a certain pressure and temperature.

[0044] Step 3: Cool and shape the product and then remove it from the mold to form the signal magnetic ring of the above structure.

[0045] Embodiment 2

[0046] like Figure 3 and Figure 4 As shown, the difference from the first embodiment is that the processing methods of the limiting structure and the motor signal magnetic ring are different.

[0047] The limiting structure includes an annular boss 13 arranged on the outer periphery of the sleeve section 11, and a limiting recess 131 or a protrusion for radial limiting is provided on the annular boss 13. The annular boss 13 is for placing the annular metal part in a forming mold, and the outer periphery of the annular metal part is stamped and stretched along its axial direction. The mold cavity of the forming mold has the same structure as the formed magnetic ring bracket 1. The annular boss 13 can be located at the end circumference of the sleeve section 11, and can also be located at the middle circumference of the sleeve section 11. The position of the annular boss 13 is related to the stamping and stretching forming mold, and a mold of a corresponding shape can be selected according to needs.

[0048] Since the magnetic ring body 2 is formed outside the magnetic ring bracket 1 by injection molding, during the injection process, the magnetic material fills the mold cavity and can cover the outer periphery of the annular boss 13. After cooling and molding, the magnetic ring body 2 cannot shake in the axial and radial directions, and will not separate from the magnetic ring bracket 1. It is firmly matched with the magnetic ring bracket 1, realizing the axial and radial limitation of the magnetic ring body 2 and improving the vibration and impact resistance of the product.

[0049] The method for processing the motor signal magnetic ring comprises the following steps:

[0050] Step 1: stamping and stretching the magnetic ring bracket 1. Place the annular metal part on a stamping and stretching machine, place the annular metal part in a forming die, and stamp and stretch the outer periphery of the annular metal part along its axial direction to form the sleeve section 11 and the annular boss 13 on its outer periphery.

[0051] Step 2: The magnetic ring body 2 is injection molded on the periphery of the magnetic ring bracket 1.

[0052] 1) Place the molded magnetic ring bracket 1 into an injection mold; 2) The mold cavity of the injection mold is set to be annular, so that the inner side of the injection mold is close to the outer periphery of the magnetic ring bracket 1, ensuring that the radial gap between the magnetic ring body 2 and the magnetic ring bracket 1 in the molded signal magnetic ring is consistent with the thickness of the injection mold; and the inner side of the injection mold clamps the edge of the annular boss 13 to ensure that the injection-molded magnetic ring body 2 can cover and position the outer edge of the annular boss 13; 3) Inject the magnetic material into the mold cavity of the mold by the injection machine at a certain pressure and temperature.

[0053] Step 3: Cool and shape the product and then remove it from the mold to form the signal magnetic ring of the above structure.

[0054] Of course, in addition to protecting the motor signal magnetic rings of the above embodiments 1 and 2, the present invention also protects other forms of signal magnetic rings with axial and radial limiting structures.

[0055] In summary, the signal magnetic ring of the present invention has a simple structure and low processing cost. It can avoid cracks caused by inconsistent expansion coefficients when the magnetic ring is subjected to certain mechanical stresses during installation or when the temperature changes drastically. It has strong vibration and impact resistance and high product reliability.

[0056] The above description is only used to illustrate some principles of the present invention. This specification is not intended to limit the present invention to the specific structure and application scope shown and described. Therefore, all corresponding modifications and equivalents that may be used belong to the patent scope applied for by the present invention.

Claims

1. A motor signal magnetic ring, characterized in that: The invention comprises a magnetic ring bracket and a magnetic ring body. The magnetic ring bracket cooperates with the rotating shaft. The magnetic ring bracket is provided with a limiting structure to prevent the magnetic ring body from falling off. The magnetic ring bracket is provided with a sleeve section that cooperates with the rotating shaft of the motor and a recess for positioning during manufacturing and magnetization. The sleeve section of the magnetic ring bracket and the magnetic ring body are radially separated by a gap of 0.1 to 15 mm, and the number of magnetizing pole pairs of the magnetic ring body is not less than 2.

2. The motor signal magnetic ring according to claim 1, characterized in that: The limiting structure comprises a flange plate arranged on the outer periphery of the sleeve section, and the aperture of the positioning hole on the flange plate is smaller than that of the other end at one end close to the magnetic ring body or is set as a countersunk hole.

3. The motor signal magnetic ring according to claim 1, characterized in that: The limiting structure comprises an annular boss arranged on the outer periphery of the sleeve section, and a limiting recess or protrusion is provided on the annular boss.

4. The motor signal magnetic ring according to claim 1, characterized in that: The magnetic ring bracket is interference fit with the motor shaft, and the fitting surface is set to be a smooth surface.

5. The motor signal magnetic ring according to claim 1, characterized in that: The magnetic ring bracket is glued to the motor shaft, and a glue storage groove is arranged on the matching surface.

6. A method for processing a motor signal magnetic ring according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: stamping and stretching of the magnetic ring bracket; Step 2: The magnetic ring bracket is placed in the injection mold as an insert, and the magnetic ring body is injection molded; Step 3: Cool and shape before demoulding.

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