Eddy current direct reading encoder

Abstract

The invention relates to the technical field of encoders, and provides an eddy current direct reading encoder. The eddy current direct-reading encoder comprises a plurality of character wheel assemblies and sampling assemblies which are alternately arranged in sequence, and a main circuit board fixedly arranged at the bottoms of the sampling assemblies, wherein the main circuit board is electrically connected with the sampling assemblies; the main circuit board is used for outputting alternating excitation current and receiving induced current; the sampling assembly can generate an alternating magnetic field under the action of the alternating excitation current; the character wheel assembly can generate eddy current under the action of the alternating magnetic field; the sampling assembly can generate the induced current under the effect of the eddy current and transmit the induced current to the main circuit board. The eddy current direct-reading encoder can realize non-contact absolute angular position measurement, and has the advantages of stable and reliable signal transmission and adaptability to severe working conditions.

Description

Technical Field

[0001] This application relates to the technical field of encoders, and particularly to an eddy current direct-read encoder. Background Technology

[0002] An encoder is a device that converts signals or data into a form that can be communicated, transmitted, and stored. Based on the readout method, it can be divided into contact and non-contact types; based on the working principle, it can be divided into incremental and absolute types. Absolute encoders have a unique digital code corresponding to each position, and the indicated value is only related to the starting and ending positions, exhibiting high stability. Incremental encoders convert displacement into periodic electrical signals and then into counting pulses, with the displacement magnitude represented by the number of pulses. Existing technologies include photoelectric direct-reading encoders using phototubes as sensors, as well as incremental encoders employing eddy current technology.

[0003] Existing photoelectric direct-reading encoders include a character wheel encoder disk, a light shield, a phototube, and a light guide plate. Their signals are transmitted through an optical path for detection. Incremental encoders employing eddy current technology typically include a partially metallized disk, a transmitting coil, a secondary coil, and a measuring device. The partially metallized disk is connected to an external rotating component under test and rotates synchronously. The transmitting coil and the secondary coil are coupled through mutual inductance. The measuring device outputs voltage pulse signals based on changes in the inductance of the secondary coil, used to measure relevant parameters of the moving rotating component.

[0004] Existing photoelectric direct-reading encoders rely on optical path transmission for signal transmission. Obstructions such as burrs, flash, bubbles, or interference light on the optical path can affect signal transmission. When applied to related instruments, the optical path environment must be strictly controlled, significantly increasing the complexity of molding, potting, and other processes. Existing incremental encoders using eddy current technology measure based on pulse signals. The power supply to the transmitting coil cannot be interrupted, and they are easily affected by external interference, potentially leading to pulse signal loss and measurement disputes. This makes them unsuitable for certain application scenarios. Summary of the Invention

[0005] In view of this, this application aims to provide an eddy current direct-read encoder to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solution of this application is implemented as follows: An eddy current direct-read encoder is characterized by comprising a plurality of sequentially alternating character wheel assemblies and sampling assemblies, and a main circuit board fixedly disposed at the bottom of the sampling assemblies, wherein the main circuit board is electrically connected to the plurality of sampling assemblies; The main circuit board is used to output alternating excitation current and receive induced current. The sampling component can generate an alternating magnetic field under the action of the alternating excitation current; The character wheel assembly is capable of generating eddy currents under the action of the alternating magnetic field; The sampling component is able to generate the induced current under the action of the eddy current and transmit it to the main circuit board.

[0007] Furthermore, the character wheel assembly includes: The character wheel body is constructed as a disc with characters engraved on a circumferential curved surface. One side has multiple meshing teeth evenly distributed in a ring, and the other side has two meshing teeth. The limiting post is coaxially arranged at the geometric center of the character wheel body; A shaft hole is formed on the limiting post along the axial direction for mounting a rotating shaft to allow the character wheel assembly to rotate around the shaft. Metal sheets, disposed on one side of the type wheel body opposite to the meshing teeth that are evenly distributed in a ring, are configured as multiple fan-shaped sheets spaced apart around the geometric center of the type wheel body to generate the eddy currents.

[0008] Furthermore, the sampling component is a high-frequency reflective sampling circuit board, comprising: The main circuit board body has plug-in pads at the bottom for limiting the main circuit board; The first transmitting coil is fixed in a ring shape on the main body of the first circuit board; The first receiving coil is disposed on the same side of the first circuit board body as the first transmitting coil, located inside the first transmitting coil, and is configured as a plurality of coils evenly arranged around the center of the first transmitting coil.

[0009] Furthermore, the first circuit board body has a central hole for mounting the limiting post and an asymmetrical process error prevention hole.

[0010] Furthermore, a grid-like magnetic shielding surface is provided inside the main body of the first circuit board.

[0011] Furthermore, the sampling component is a low-frequency through-beam sampling circuit board, comprising: The second circuit board body has plug-in pads at the bottom for limiting the main circuit board; The second transmitting coil is fixed in a ring shape on the main body of the second circuit board; The second receiving coil is disposed on the side of the second circuit board body opposite to the second transmitting coil, and is configured as a plurality of coils evenly arranged around the center of the second transmitting coil.

[0012] Furthermore, the second circuit board body has a central hole for mounting the limiting post and an asymmetrical process error prevention hole.

[0013] Furthermore, the number of the first or second receiving coil is five, and the number of the metal sheets is three; The three metal sheets include a large sheet and two different small sheets spaced apart from each other. The large sheet can act on at most two adjacent first receiving coils or second receiving coils at the same time, and the small sheets can act on at most one first receiving coil or second receiving coil at the same time. The spacing between the large piece and the small piece is at least large enough to accommodate one of the first receiving coils or the second receiving coil.

[0014] Compared with existing technologies, the eddy current direct-read encoder proposed in this application has the following advantages: (1) This application outputs an alternating excitation current through the main circuit board, which causes the transmitting coil of the sampling component to generate an alternating magnetic field. The metal sheet of the character wheel component generates eddy currents under the action of the alternating magnetic field. The receiving coil of the sampling component induces eddy currents and generates induced currents that are transmitted to the main circuit board, thereby achieving accurate detection of the absolute angular position of the character wheel component. It does not require continuous power supply and can still be accurately read under power failure or undervoltage conditions. It is also not easily affected by external interference and therefore does not become inaccurate.

[0015] (2) This application sets asymmetric process anti-fool holes on the sampling circuit board to ensure the accuracy of its assembly and welding with the main circuit board, and avoid failure caused by the inductor coil being too far away from the metal sheet; the component adopts a modular design, which is simple in structure and easy to assemble. The planar coil design of the sampling circuit board requires little installation space, supports potting and sealing, and is suitable for various working conditions such as water, gas and heat instruments.

[0016] (3) This application sets up multiple uniformly arranged receiving coils in the sampling component, and with the distribution of metal plates in the character wheel component, it ensures that some receiving coils are induced with eddy currents at any position, so as to realize fault self-diagnosis; the grid-shaped magnetic shielding surface of the reflective sampling circuit board can reduce external magnetic interference and its own electromagnetic interference, further improving the reliability of detection. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of the high-frequency reflective eddy current direct-read encoder described in the embodiments of this application; Figure 2 This is a schematic diagram of the front and side structure of the character wheel assembly described in the embodiments of this application; Figure 3 This is a schematic diagram of the front and side structure of the high-frequency reflective sampling circuit board described in the embodiments of this application; Figure 4This is a schematic diagram of the structure of the low-frequency through-beam eddy current direct-read encoder described in the embodiments of this application; Figure 5 This is a schematic diagram of the front and side structure of the low-frequency through-beam sampling circuit board described in the embodiments of this application; Figure 6 This is a schematic diagram of the encoding process of the eddy current direct-read encoder described in an embodiment of this application.

[0018] Explanation of reference numerals in the attached figures: 1. Character wheel assembly; 1-1. Metal sheet; 1-2. Limiting post; 1-3. Shaft hole; 2. High-frequency reflective sampling circuit board; 2-1. First circuit board body; 2-2. First transmitting coil; 2-3. First receiving coil; 2-4. Magnetic shielding surface; 2-5. Center hole; 2-6. Asymmetrical process anti-fool hole; 3. Main circuit board; 4. Low-frequency through-beam sampling circuit board; 4-1. Second transmitting coil; 4-2. Second receiving coil; 4-3. Center hole; 4-4. Asymmetrical process anti-fool hole; 4-5. Second circuit board body. Detailed Implementation

[0019] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0021] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0023] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0024] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0025] Example 1 Existing photoelectric direct-reading encoders include a character wheel encoder disk, a light shield, a phototube, and a light guide plate. Their signals are transmitted through an optical path for detection. Incremental encoders employing eddy current technology typically include a partially metallized disk, a transmitting coil, a secondary coil, and a measuring device. The partially metallized disk is connected to an external rotating component under test and rotates synchronously. The transmitting coil and the secondary coil are coupled through mutual inductance. The measuring device outputs voltage pulse signals based on changes in the inductance of the secondary coil, used to measure relevant parameters of the moving rotating component.

[0026] Existing photoelectric direct-reading encoders rely on optical path transmission for signal transmission. Obstructions such as burrs, flash, bubbles, or interference light on the optical path can affect signal transmission. When applied to related instruments, the optical path environment must be strictly controlled, significantly increasing the complexity of molding, potting, and other processes. Existing incremental encoders using eddy current technology measure based on pulse signals. The power supply to the transmitting coil cannot be interrupted, and they are easily affected by external interference, potentially leading to pulse signal loss and measurement disputes. This makes them unsuitable for certain application scenarios.

[0027] In view of this, in order to overcome the shortcomings of the prior art, this embodiment proposes a high-frequency reflective eddy current direct-read encoder.

[0028] Reference Figure 1 and Figure 4The eddy current direct-read encoder of this application includes multiple character wheel assemblies 1 and sampling assemblies. The character wheel assemblies 1 and sampling assemblies are arranged alternately in sequence. A main circuit board 3 is fixedly mounted on the bottom of the sampling assemblies and is electrically connected to the multiple sampling assemblies. The main circuit board 3 is used to output alternating excitation current and receive induced current, providing power support for the entire detection process and receiving and analyzing signals. Under the action of the alternating excitation current output by the main circuit board 3, the sampling assemblies can generate a stable alternating magnetic field. When the character wheel assembly 1 is within the range of this alternating magnetic field, eddy currents are induced. The sampling assemblies can sense the presence of eddy currents and generate induced currents accordingly, transmitting the induced currents to the main circuit board 3 for subsequent processing. This structural layout and working principle enable close collaboration among the components, achieving non-contact detection based on the eddy current effect, avoiding the wear problems caused by contact measurement. Simultaneously, the stable connection between components and the signal transmission path design ensure the stability of the detection process, unaffected by external interference factors, thereby achieving accurate position detection.

[0029] Reference Figure 1 , Figure 2 and Figure 4 The character wheel assembly 1 includes a character wheel body, a limiting post 1-2, a shaft hole 1-3, and a metal plate 1-1. The character wheel body has a disc-shaped structure with characters, such as Arabic numerals 0-9, engraved on its circumferential curved surface to facilitate subsequent reading of position information. One side of the character wheel body has multiple meshing teeth evenly distributed in a ring, and the other side has two meshing teeth for transmission engagement with other components. The limiting post 1-2 is coaxially positioned at the geometric center of the character wheel body, providing a stable mounting base for the shaft hole 1-3. The shaft hole 1-3 is formed along the axial direction on the limiting post 1-2 and is specifically used to mount the rotating shaft, allowing the character wheel assembly 1 to rotate smoothly around the shaft. The metal plate 1-1 is positioned on the side of the character wheel body opposite to the side with the multiple meshing teeth distributed in a ring, i.e., on the side with two meshing teeth. The metal plate 1-1 has a fan-shaped structure arranged at intervals around the geometric center of the character wheel body, and its function is to generate eddy currents in an alternating magnetic field. The fan-shaped structure and spaced arrangement of the metal sheet 1-1 can fully contact the magnetic field generated by the sampling component, ensuring the stable generation of eddy currents. Its installation position is close to the sampling component, which further improves the efficiency of interaction with the magnetic field, providing a reliable prerequisite for the subsequent generation of induced current and ensuring the accuracy of position detection.

[0030] Reference Figure 1 and Figure 3The sampling component can adopt a high-frequency reflective sampling circuit board 2, including a first circuit board body 2-1, a first transmitting coil 2-2, and a first receiving coil 2-3. The bottom of the first circuit board body 2-1 is provided with plug-in pads. The function of the plug-in pads is to limit the position of the main circuit board 3, ensuring a precise and secure connection between the main circuit board 3 and the high-frequency reflective sampling circuit board 2, and avoiding installation deviations that could affect signal transmission. The first transmitting coil 2-2 is fixedly mounted on the first circuit board body 2-1 in a ring structure. The ring structure is beneficial for generating a uniform and stable alternating magnetic field, providing sufficient magnetic field conditions for the generation of eddy currents in the metal sheet 1-1 of the character wheel assembly 1. The first receiving coil 2-3 is located on the same side of the first circuit board body 2-1 as the first transmitting coil 2-2, and is located inside the first transmitting coil 2-2, arranged uniformly around the center of the first transmitting coil 2-2.

[0031] Reference Figure 3 The arrangement of the first transmitting coil 2-2 and the first receiving coil 2-3 on the same side shortens the magnetic field transmission path and reduces signal loss. The evenly arranged receiving coils can fully capture the magnetic field changes generated by the eddy current, improve the sensitivity to the induced current, and thus ensure the accuracy of the encoder in position detection.

[0032] Reference Figure 6 Multiple first receiving coils 2-3 are evenly arranged around the center of the first transmitting coil 2-2, corresponding to the spaced metal pieces 1-1. Only the first receiving coils 2-3 overlapping with the metal pieces 1-1 will generate an induced current under the influence of the eddy currents in the metal pieces 1-1. The first receiving coils 2-3 that generate an induced current are at a high level, denoted as 1, while those that do not generate an induced current are at a low level, denoted as 0. Through this structure, the rotation angle information of the character wheel assembly 1 is equivalent to the position information of the metal pieces 1-1. The position information of the metal pieces 1-1 is equivalent to a data string consisting of 1s and 0s, with the same number of bits as the first receiving coils 2-3, and is transmitted to the main circuit board 3 via induced current. The characters corresponding to the data string are defined according to the actual situation and input to the main circuit board 3. The main circuit board 3 decodes the data string to complete the encoding of the angle information of the character wheel assembly 1. This structural combination ensures that at any position of rotation of the character wheel assembly 1, some receiving coils can sense the magnetic field generated by eddy currents, while others cannot sense it, thus forming a unique signal combination.

[0033] Reference Figure 3The high-frequency reflective sampling circuit board 2 has a central hole 2-5 and an asymmetrical anti-misplacement hole 2-6 on its first circuit board body 2-1. The central hole 2-5 is specifically used to install the limiting post 1-2 of the character wheel assembly 1. Through the cooperation of the limiting post 1-2 and the central hole 2-5, precise positioning of the character wheel assembly 1 and the high-frequency reflective sampling circuit board 2 can be achieved, ensuring that the metal piece 1-1 of the character wheel assembly 1 and the coil of the sampling circuit board are in the optimal relative position. This avoids insufficient magnetic field effect due to positional deviation, which would affect the generation of eddy currents and the detection of induced current. The asymmetrical anti-misplacement hole 2-6 serves to prevent mistakes during assembly, guiding the operator to install in the correct direction and preventing the coil from being too far from the metal piece 1-1 or misaligned due to reverse installation, thus preventing encoder failure. These two holes ensure the accuracy and reliability of component installation from both positioning and misplacement perspectives.

[0034] Reference Figure 3 The high-frequency reflective sampling circuit board 2 has a grid-like magnetic shielding surface 2-4 inside its first circuit board body 2-1. This grid structure effectively saves materials and reduces production costs while ensuring magnetic shielding effectiveness. The magnetic shielding surface 2-4 can reduce the impact of external magnetic interference on the alternating magnetic field generated by the first transmitting coil 2-2 and the induced current induced by the first receiving coil 2-3 by reflecting and absorbing external magnetic fields. It also reduces electromagnetic interference generated by the sampling circuit board itself on other components. The reduction of external magnetic interference makes the alternating magnetic field more stable, and the generation of eddy currents and the transmission of induced currents are not disturbed, thereby improving the stability and accuracy of the encoder's detection signal and ensuring that the encoder can perform its detection function normally even in complex working environments.

[0035] Example 2 This embodiment proposes a low-frequency through-beam eddy current direct-read encoder. The main difference between the low-frequency through-beam eddy current direct-read encoder in this embodiment and the high-frequency reflective eddy current direct-read encoder in Embodiment 1 lies in the sampling component.

[0036] Reference Figure 4 and Figure 5In this embodiment, the sampling component employs a low-frequency through-beam sampling circuit board 4, which includes a second circuit board body 4-5, a second transmitting coil 4-1, and a second receiving coil 4-2. The bottom of the second circuit board body 4-5 is provided with plug-in pads, which are used to limit the position of the main circuit board 3, ensuring a precise and secure connection between the main circuit board 3 and the low-frequency through-beam sampling circuit board 4, thus guaranteeing stable signal transmission. The second transmitting coil 4-1 is fixedly arranged in a ring on the second circuit board body 4-5, generating a stable alternating magnetic field that meets the requirements of low-frequency operation. The second receiving coil 4-2 is located on the side of the second circuit board body 4-5 opposite to the second transmitting coil 4-1, and is evenly arranged around the center of the second transmitting coil 4-1. The back-to-back arrangement of the transmitting and receiving coils on both sides of the second circuit board body 4-5 reduces mutual interference between the coils and ensures that the metal plate 1-1 of the character wheel assembly 1 is fully immersed in the magnetic field, guaranteeing the effective generation of eddy currents. The low-frequency operating mode has relatively lower requirements for battery performance and electronic modules, making it easier to implement and promote. At the same time, this structure can also ensure that the receiving coil can stably generate induced current, thus achieving accurate position detection.

[0037] Reference Figure 5 The low-frequency through-beam sampling circuit board 4 has a central hole 4-3 and an asymmetrical anti-mistake hole 4-4 on its second circuit board body 4-5. The central hole 4-3 is used to install the limiting post 1-2 of the character wheel assembly 1. Through the cooperation of the limiting post 1-2 and the central hole 4-3, the low-frequency through-beam sampling circuit board 4 and the character wheel assembly 1 are precisely positioned, ensuring that the relative positions of the metal piece 1-1, the second transmitting coil 4-1, and the second receiving coil 4-2 meet the detection requirements. This ensures that the magnetic field and the metal piece 1-1 can fully interact, providing structural support for the stable generation of eddy currents. The asymmetrical anti-mistake hole 4-4 acts as a mistake-proof device during assembly, preventing misalignment of the coil and metal piece 1-1 due to incorrect installation direction, which could affect the detection effect or even cause encoder failure. The design of these two holes ensures the accuracy and reliability of the low-frequency through-beam sampling circuit board 4's assembly with other components, ensuring the structural stability and operational effectiveness of the entire encoder.

[0038] Reference Figure 2 , Figure 3 and Figure 5The first receiving coil 2-3 or the second receiving coil 4-2 and the metal sheet 1-1 are arranged in the following correspondence in terms of position and number: There are five first receiving coils 2-3 or the second receiving coil 4-2. There are three metal sheets 1-1, including one large sheet and two different smaller sheets, which are spaced apart. The large sheet can act on at least two adjacent first receiving coils 2-3 or the second receiving coil 4-2, and the smaller sheets can act on a single first receiving coil 2-3 or the second receiving coil 4-2. The spacing between the large and small sheets is sufficient to accommodate at least one first receiving coil 2-3 or the second receiving coil 4-2.

[0039] Reference Figure 6 Multiple second receiving coils 4-2 are evenly arranged around the center of the second transmitting coil 4-1, corresponding to the spaced metal pieces 1-1. Only the second receiving coils 4-2 overlapping with the metal pieces 1-1 will generate an induced current under the influence of the eddy currents in the metal pieces 1-1. The second receiving coils 4-2 that generate an induced current are at a high level, denoted as 1, while those that do not generate an induced current are at a low level, denoted as 0. Through this structure, the rotation angle information of the character wheel assembly 1 is equivalent to the position information of the metal pieces 1-1. The position information of the metal pieces 1-1 is equivalent to a data string consisting of 1s and 0s with the same number of bits as the second receiving coils 4-2, and is transmitted to the main circuit board 3 via induced current. The characters corresponding to the data string are defined according to the actual situation and input to the main circuit board 3. The main circuit board 3 decodes the data string to complete the encoding of the angle information of the character wheel assembly 1. This structural combination ensures that at any position of rotation of the character wheel assembly 1, some receiving coils can sense the magnetic field generated by eddy currents, while others cannot sense it, thus forming a unique signal combination.

[0040] By analyzing the differences in these signal combinations, the different positions of the character wheel assembly 1 can be accurately distinguished. Furthermore, since there are always inductive and non-inductive receiving coils, there will be no single fully on or fully off state when analyzing the signal. This allows for timely detection of faults such as open circuits or external interference, enabling self-diagnosis and further improving the encoder's detection reliability and safety.

[0041] By setting the number of the first receiving coil 2-3 or the second receiving coil 4-2 to five, the length of the data string generated during the encoding process is five. Combined with the structural design of the metal sheet 1-1, a total of 2... 5-2 (i.e., all possible permutations and combinations minus the structurally impossible 11111 and 00000) equals 30 unique data strings. Based on the engraving of the character wheel assembly 1, these 30 data strings can be evenly distributed among the ten Arabic numerals 0-9, with three strings per group. Since each Arabic numeral corresponds to more than one unique data string, this redundancy completely eliminates encoding failures caused by assembly errors, gaps, or the special position of the character wheel assembly 1, further improving the encoder's detection reliability and operational safety. Using two different small pieces effectively avoids data string confusion.

[0042] The above descriptions are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. An eddy current direct-read encoder, characterized in that, It includes multiple sequentially alternating character wheel assemblies (1) and sampling assemblies, as well as a main circuit board (3) fixed at the bottom of the sampling assemblies, the main circuit board (3) being electrically connected to the multiple sampling assemblies; The main circuit board (3) is used to output alternating excitation current and receive induced current; The sampling component is capable of generating an alternating magnetic field under the action of the alternating excitation current; The character wheel assembly (1) is capable of generating eddy currents under the action of the alternating magnetic field; The sampling component is able to generate the induced current under the action of the eddy current and transmit it to the main circuit board (3).

2. The eddy current direct-read encoder according to claim 1, characterized in that, The character wheel assembly (1) includes: The character wheel body is constructed as a disc with characters engraved on a circumferential curved surface. One side has multiple meshing teeth evenly distributed in a ring, and the other side has two meshing teeth. The limiting post (1-2) is coaxially arranged at the geometric center of the character wheel body; A shaft hole (1-3) is formed on the limiting post (1-2) along the axial direction for mounting a rotating shaft to allow the character wheel assembly (1) to rotate around the shaft; Metal sheets (1-1) are disposed on the side of the character wheel body opposite to the meshing teeth that are uniformly distributed in a ring. They are constructed as a plurality of fan-shaped sheets spaced apart around the geometric center of the character wheel body to generate the eddy current.

3. The eddy current direct-read encoder according to claim 2, characterized in that, The sampling component is a high-frequency reflective sampling circuit board (2), comprising: The first circuit board body (2-1) has a plug-in pad at the bottom for limiting the main circuit board (3). The first transmitting coil (2-2) is fixed in a ring shape on the main body of the first circuit board (2-1); The first receiving coil (2-3) is disposed on the same side of the first circuit board body (2-1) as the first transmitting coil (2-2), located inside the first transmitting coil (2-2), and is configured as a plurality of coils evenly arranged around the center of the first transmitting coil (2-2).

4. The eddy current direct-read encoder according to claim 3, characterized in that, The first circuit board body (2-1) has a center hole (2-5) for mounting the limiting post (1-2) and an asymmetrical process anti-fool hole (2-6).

5. An eddy current direct-read encoder according to claim 3, characterized in that, The first circuit board body (2-1) has a grid-like magnetic shielding surface (2-4) inside.

6. An eddy current direct-reading encoder according to claim 2, characterized in that, The sampling component is a low-frequency through-beam sampling circuit board (4), comprising: The second circuit board body (4-5) has a plug-in pad at the bottom for limiting the main circuit board (3). The second transmitting coil (4-1) is fixed in a ring shape on the main body of the second circuit board (4-5); The second receiving coil (4-2) is disposed on the side of the second circuit board body (4-5) opposite to the second transmitting coil (4-1), and is configured to be a plurality of coils evenly arranged around the center of the second transmitting coil (4-1).

7. An eddy current direct-read encoder according to claim 6, characterized in that, The second circuit board body (4-5) has a center hole (4-3) for mounting the limiting post (1-2) and an asymmetrical process anti-fool hole (4-4).

8. An eddy current direct-read encoder according to claim 3 or 6, characterized in that, The number of the first receiving coil (2-3) or the second receiving coil (4-2) is five, and the number of the metal sheet (1-1) is three; The three metal sheets (1-1) include a large sheet and two different small sheets spaced apart from each other. The large sheet can act on at most two adjacent first receiving coils (2-3) or second receiving coils (4-2) at the same time, and the small sheets can act on at most one first receiving coil (2-3) or second receiving coil (4-2) at the same time. The spacing between the large piece and the small piece is at least large enough to accommodate one of the first receiving coils (2-3) or the second receiving coil (4-2).

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