Magnetic encoder
By using spatial magnetic field gradient modulation and single-chip detection, combined with flexible cabling, the problem of excessively large magnetic encoder size has been solved, resulting in a smaller magnetic encoder design suitable for portable digital products.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TENGFEI ELECTROINCS YUEQING CITY
- Filing Date
- 2025-06-17
- Publication Date
- 2026-04-21
AI Technical Summary
The packaging size of existing magnetic encoders is difficult to further reduce, especially in terms of thickness and area, which limits their application in portable digital products.
By employing a spatial magnetic field gradient modulation mechanism and a single-chip detection architecture, and using flexible flat cables to replace rigid printed circuit boards, combined with multi-pole magnetized rings or discrete magnetic pole arrays, accurate detection of rotational motion is achieved.
The package size of the magnetic encoder has been significantly reduced, especially its thickness and area, while maintaining high-precision detection capability of rotational motion parameters.
Smart Images
Figure CN224151735U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of magnetic encoders, and in particular to a magnetic encoder. Background Technology
[0002] Magnetic encoders, as important motion sensing devices, detect position, speed, and direction by sensing changes in magnetic fields, and are widely used in industrial automation, robotics, consumer electronics, and other fields. In current technology, mainstream designs typically rely on two parallel magnetic wheels with specific pole pairs (N / S poles) and a Hall sensor array fixed beneath them. The basic principle of this structure is that as the magnetic wheels rotate with the object being measured, the Hall sensors beneath them sense the periodic changes in magnetic flux. By analyzing the phase difference signals (such as sine and cosine waves) output by the two sensors, the rotation angle, rotation speed, and direction of rotation (forward or reverse) of the magnetic wheels can be accurately calculated. Currently, to achieve effective signal reception, processing, and transmission, Hall sensor elements generally need to be mounted and electrically connected on a printed circuit board (PCB). The PCB serves as both the physical carrier and electrical interconnection platform for the sensor, and also houses necessary signal conditioning circuitry (such as amplification and filtering) and even primary processing units.
[0003] However, this traditional PCB-based Hall sensor design also presents a significant limitation: the overall package size of the magnetic encoder is difficult to make sufficiently compact. This is mainly due to two reasons: first, the two magnetic wheels must maintain a certain distance to achieve effective phase difference detection, which itself occupies space in the width direction; second, and more importantly, the PCB board becomes an indispensable key component for integrating and supporting the Hall sensor chip and achieving connection with external circuits. The PCB not only has physical thickness and size requirements, but also needs to leave additional space for component layout, wiring, and heat dissipation. Therefore, the PCB-based structure of the Hall element makes it difficult to further significantly reduce the thickness and area of the entire sensing module, including the magnetic wheels, sensor, and circuit board. This size limitation, especially in the thickness direction, has become one of the key obstacles hindering the deep penetration of magnetic encoders into smaller, more integrated portable digital products (such as hinge angle detection in ultra-thin laptops, position feedback in miniature gimbal cameras, and motion sensing in wearable devices).
[0004] Therefore, developing a new magnetic encoder technology that can break through the constraints of existing structures, significantly reduce packaging size, and especially reduce thickness and area occupation, has important practical significance and market value. Utility Model Content
[0005] The purpose of this application is to overcome at least one deficiency of the prior art and to provide a magnetic encoder with a simpler structure.
[0006] To achieve the above objectives, this application discloses a magnetic encoder comprising a mechanical body consisting of a fixed base and a rotatable component. The rotatable component achieves rotational motion about an axis relative to the fixed base through an axial support structure. The circumferential surface of the rotatable component is provided with periodically distributed magnetic encoding structures, configured to form a continuously varying spatial magnetic field gradient distribution. The fixed base integrates a magnetic sensor chip, whose output pins are electrically connected via flexible ribbon cables, with the signal output terminal extending to an external signal processing circuit board.
[0007] Preferably, there is one magnetic sensor chip.
[0008] As an optional technical solution, two or more magnetic sensor chips are arranged side by side inside the fixed base.
[0009] Preferably, the magnetic sensor chip includes at least two magnetic induction modules.
[0010] Preferably, the magnetic coding structure is implemented using a multi-pole magnetized ring. The outer edge of the multi-pole magnetized ring forms a geometric modulation surface composed of several equally spaced protrusions and grooves. This geometric modulation surface utilizes the difference in axial spacing between the top regions of the protrusions and the bottom regions of the grooves and the detection plane of the magnetic sensor chip to generate a periodic spatial magnetic field distribution.
[0011] Preferably, the magnetic encoding structure is implemented as a discrete magnetic pole array. This discrete magnetic pole array consists of multiple independent permanent magnet units uniformly arranged along the circumference of the rotatable component. Each independent permanent magnet unit is arranged with alternating N and S poles, forming a periodic spatial magnetic field distribution characteristic through magnetic field synthesis.
[0012] As an optional technical solution, the magnetic encoding structure adopts a single magnet structure. Preferably, the magnet structure is a magnetic ring or a magnetic disc.
[0013] Preferably, the fixed base and the protective housing form a sealed cavity through a joint structure. This sealed cavity encapsulates the rotation area of the rotatable component and the magnetic sensor chip within an internal isolated space.
[0014] Preferably, the fixed base is equipped with a spring plate that cooperates with the rotatable part, and the rotational damping is achieved by the cooperation of the spring plate with the circumferentially arranged limiting teeth of the rotatable part.
[0015] Preferably, the magnetic sensor chip is disposed within the fixed base and opposite to the side of the rotatable component.
[0016] Compared with existing technologies, this application replaces the traditional dual-magnetic-wheel parallel layout with a spatial magnetic field gradient modulation mechanism and a single-chip detection architecture. The application of flexible cabling replaces the rigid printed circuit board carrier structure, thereby reducing the size footprint of the magnetic encoder in the radial plane and reducing the axial stacking thickness while maintaining the ability to accurately detect rotational motion parameters.
[0017] The beneficial effects listed above are not exhaustive of all advantages. Other potential beneficial effects and detailed technical implementation methods will be further disclosed in the embodiments or other descriptive sections of this application. Attached Figure Description
[0018] A better understanding of various aspects of this disclosure will be achieved by reading the following detailed description in conjunction with the accompanying drawings. The positions, dimensions, and extents of the structures shown in the drawings, etc., do not always represent actual positions, dimensions, and extents. In the drawings:
[0019] Figure 1 This is an exploded view of one embodiment disclosed in this application.
[0020] Figure 2 This is an exploded view of the structure of one embodiment disclosed in this application from another perspective. Detailed Implementation
[0021] The present disclosure will now be described with reference to the accompanying drawings, which illustrate several embodiments of the present disclosure. However, it should be understood that the present disclosure can be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure more complete and to fully illustrate the scope of protection of the present disclosure to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide further additional embodiments.
[0022] It should be understood that the same reference numerals denote the same elements in all the accompanying drawings. For clarity, the dimensions of certain features may be modified in the drawings.
[0023] It should be understood that the terminology used in this specification is for describing specific embodiments only and is not intended to limit this disclosure. All terms used in this specification (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. For the sake of brevity and / or clarity, techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail; however, where appropriate, such techniques, methods, and apparatus should be considered part of this specification.
[0024] Unless otherwise specified, the singular forms “a,” “the,” and “the” used in this specification include the plural forms. The terms “comprising,” “including,” and “containing” used in this specification indicate the presence of the claimed feature but do not exclude the presence of one or more other features. The term “and / or” used in this specification includes any and all combinations of one or more of the relevant listed items.
[0025] See attached document Figure 1 and 2 This embodiment provides an exemplary structure of a compact magnetic encoder based on a spatial magnetic field gradient modulation mechanism, comprising a mechanical body consisting of a fixed base 1 and a rotatable component 2. The fixed base 1 enables the rotatable component 2 to rotate around an axis via an axial support structure, wherein the axial support structure 2 can be a standard rotary support element such as a ball bearing, or it can be directly drilled. A periodic magnetic encoding structure 3 is provided on the rotating circumferential surface of the rotatable component 2, which is configured to generate a continuously changing spatial magnetic field gradient distribution. A single magnetic sensor chip 4 is integrated inside the fixed base 1, and its output pins are electrically connected via a flexible ribbon cable 5. The signal output terminal extends to an external signal processing circuit board (not shown in the figure). A protective housing 6 and the fixed base 1 form a sealed cavity through a joint structure, encapsulating the rotating area and the magnetic sensor chip 5 in an electromagnetically isolated environment.
[0026] The fixed base 1 is a metal bracket with a mounting flange and locating pin holes on its axial end face for quick positioning and installation on the equipment frame. The rotation axis of the rotatable component 2 is coaxially arranged with the central through hole of the fixed base 1. In particular, a spring plate 7 is installed inside the fixed base 1. The bent end of the spring plate 7 forms a groove structure that slides with the circumferentially distributed limiting protrusions 8 of the rotatable component 2. Rotational damping is controlled by adjusting the preload of the spring plate 7.
[0027] The implementation of the magnetic encoding structure 3 includes two preferred schemes: The first scheme employs a multi-pole magnetized ring, the outer edge of which is machined with multiple trapezoidal protrusions and arc-shaped grooves spaced at equal angles. The axial distance between the top region of the protrusions and the detection plane of the magnetic sensor chip 4 is smaller than the distance between the bottom regions of the grooves. This difference in axial distance creates a periodic sinusoidal magnetic field distribution on the sensor detection plane. For example... Figure 1 and 2 As shown, the second scheme adopts a discrete magnetic pole array, which consists of several independent permanent magnet units 9 evenly arranged along the circumference. Each permanent magnet unit 9 is magnetized in an alternating manner of N pole and S pole, and a square wave gradient distribution is formed by spatial synthesis of the magnetic field.
[0028] In this embodiment, the magnetic sensor chip 4 is mounted on the inner side of the fixed base, with its sensitive surface facing the radial side of the rotatable component 2. Specifically, the sensor chip can be an IQS324 chip from AZOTEQ or other magnetic sensors with equivalent functions, which convert the sensed magnetic field strength and direction changes into electrical signal outputs based on the magnetoelectric conversion effect. The differential output pins of the sensor chip are connected to the contact pads of the flexible printed line 5 via a bonding process. This flexible printed line 5 can be double-sided wiring on a polyimide substrate.
[0029] In practical operation, when the rotatable component 2 drives the magnetic encoding structure 3 to rotate, the spatial magnetic field gradient changes continuously with the structure's position. The magnetic sensor chip 4 senses the change in magnetic field and outputs a differential signal to an external signal processing circuit board. After signal conversion and angle calculation algorithms, the precise rotation angle value is calculated. The single-chip detection architecture eliminates the alignment deviation error in the traditional dual-magnetic-wheel scheme, and the angle nonlinearity is optimized to a high level of accuracy.
[0030] Compared to the existing application of dual-magnetic wheel encoders in mice, the compact design of this embodiment significantly reduces the installation space requirements.
[0031] It should be understood that the specific circuit design of the external signal processing circuit is a well-known technology in this field; for example, angle calculation can be achieved using a standard resolver-to-digital converter chip. Existing technologies such as the surface treatment process of the protective housing and the magnetization technology of the magnetic encoding structure will not be elaborated upon.
[0032] While exemplary embodiments of this disclosure have been described, those skilled in the art will understand that various changes and modifications can be made to the exemplary embodiments of this disclosure without departing from the spirit and scope thereof. Therefore, all changes and modifications are included within the scope of protection of this disclosure as defined by the claims. This disclosure is defined by the appended claims, and equivalents of those claims are also included.
Claims
1. A magnetic encoder, characterized by The magnetic encoder comprises a mechanical body consisting of a fixed base and a rotatable component. The rotatable component achieves rotational motion about an axis relative to the fixed base through an axial support structure. The rotating circumferential surface of the rotatable component is provided with a periodically distributed magnetic coding structure, which is configured to form a continuously varying spatial magnetic field gradient distribution. The fixed base integrates a magnetic sensor chip, and the output pins of the magnetic sensor chip are electrically connected through a flexible ribbon cable, with the signal output terminal extending to an external signal processing circuit board.
2. A magnetic encoder as claimed in claim 1, characterised in that, The magnetic coding structure adopts a multi-pole magnetized ring; the outer edge of the multi-pole magnetized ring forms a geometric modulation surface composed of several convex teeth and grooves distributed at equal angles; the geometric modulation surface utilizes the difference in axial spacing between the top area of the convex teeth and the bottom area of the grooves to the detection plane of the magnetic sensor chip to generate a periodic spatial magnetic field distribution.
3. A magnetic encoder as claimed in claim 1, characterised in that, The magnetic coding structure is implemented as a discrete magnetic pole array; the discrete magnetic pole array consists of multiple independent permanent magnet units uniformly arranged along the circumference of the rotatable component; each independent permanent magnet unit is arranged in an alternating N-pole and S-pole manner, forming a periodic spatial magnetic field distribution feature through magnetic field synthesis.
4. A magnetic encoder as claimed in claim 1, characterised in that, The magnetic encoding structure adopts a single magnet structure.
5. A magnetic encoder as claimed in claim 4, characterised in that, The magnet structure is a magnetic ring or a magnetic disc.
6. A magnetic encoder as claimed in claim 1, characterised in that The fixed base and the protective housing form a sealed cavity through a joint structure; this sealed cavity encapsulates the rotation area of the rotatable component and the magnetic sensor chip in an internal isolation space.
7. A magnetic encoder as claimed in claim 1, characterised in that, The fixed base is equipped with a spring plate that mates with the rotatable part. Rotational damping is achieved by the spring plate engaging with the circumferentially oriented limiting teeth of the rotatable part.
8. A magnetic encoder as claimed in claim 1, characterised in that, The magnetic sensor chip is housed within a fixed base and faces the side of the rotatable component.
9. A magnetic encoder as claimed in claim 1, characterised in that, The magnetic sensor chip contains at least two magnetic induction modules.
10. A magnetic encoder as claimed in claim 1, characterised in that, Two or more magnetic sensor chips are arranged side by side inside the fixed base.