Capacitive encoder and electronic device
By incorporating a metal sheet structure with varying area in a capacitive encoder, signal reception capability is improved, solving the problem of balancing encoder cost and accuracy, and achieving high-precision, low-cost rotation angle detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHIPSEMI SEMICON (NINGBO) CO LTD
- Filing Date
- 2025-05-20
- Publication Date
- 2026-06-12
AI Technical Summary
Existing encoders struggle to balance cost and accuracy. Photoelectric encoders have low accuracy and are susceptible to external magnetic interference, which affects their accuracy.
Design a capacitive encoder that improves signal reception by setting a first metal plate and a second metal plate, utilizing the area difference, and enhances the detection sensitivity of the capacitive structure to achieve high-precision and low-cost rotation angle detection.
It improves the detection sensitivity of capacitive encoders, enabling low-cost, high-precision detection of shaft rotation angle. Metal parts do not require circuit connections, resulting in high flexibility.
Smart Images
Figure CN224353846U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of encoders, and in particular to a capacitive encoder and electronic device. Background Technology
[0002] An encoder is a sensor used to measure rotational angle or linear displacement. Its main function is to convert mechanical motion into electrical or digital signals, which are then fed back to the control system to provide position, speed, or angle information, thereby enabling precise control of electronic equipment.
[0003] Currently, encoders are divided into various types, such as photoelectric encoders and magnetoelectric encoders. Low-end photoelectric encoders have low accuracy, while high-end photoelectric encoders are very expensive, making it difficult to balance cost and accuracy in photoelectric encoders. Electromagnetic encoders are susceptible to external magnetic interference, affecting their accuracy. Therefore, the industry needs an encoder structure that balances accuracy and cost. Utility Model Content
[0004] The purpose of this utility model embodiment is to provide a capacitive encoder and electronic device. Based on a high-precision, low-cost capacitive encoder, a first metal plate and a second metal plate are set to realize the transmission of electrical signals. By controlling the area difference between the first metal plate and the second metal plate, the reception of signal on the transmitting plate is improved, thereby improving the detection sensitivity of the capacitive structure.
[0005] To solve the above-mentioned technical problems, embodiments of this utility model provide a capacitive encoder, including: a rotating shaft, a transmitting electrode plate, a receiving electrode plate, a support member disposed between the transmitting electrode plate and the receiving electrode plate, and a metal part disposed on the support member; the transmitting electrode plate and the receiving electrode plate are disposed opposite to each other along the axial direction of the rotating shaft; the metal part includes: a first metal sheet, a second metal sheet, and a connector connecting the first metal sheet and the second metal sheet; the first metal sheet is disposed on a first surface of the support member facing the transmitting electrode plate, and the second metal sheet is disposed on a second surface of the support member facing the receiving electrode plate, wherein the area of the first metal sheet is larger than the area of the second metal sheet; there are multiple receiving electrode plates, and the facing area between the second metal sheet and at least one receiving electrode plate changes during the rotation of the rotating shaft; the rotation angle of the rotating shaft is determined based on the signal changes on the multiple receiving electrode plates.
[0006] An embodiment of this utility model also provides an electronic device, including the above-described capacitive encoder.
[0007] Compared to existing technologies, this embodiment of the invention features a capacitive encoder in which the transmitting and receiving plates are arranged opposite each other along the axis of the rotating shaft. A support and a metal component are placed between the transmitting and receiving plates to assist in the transmission of signals from the transmitting plate to the receiving plate. The metal component includes a first metal sheet, a second metal sheet, and a connector linking the first and second metal sheets. The first metal sheet is opposite to the transmitting plate, and the second metal sheet is opposite to the receiving plate. The area of the first metal sheet is larger than that of the second metal sheet. The larger area of the first metal sheet opposite to the transmitting plate facilitates the reception of more signals from the transmitting plate. When the shaft rotates by the same angle, the change in the capacitance signal generated by the capacitive structure is greater, thereby improving the detection sensitivity of the capacitive structure. Multiple receiving plates are used, and the facing area between the second metal sheet and at least one receiving plate changes during shaft rotation. Based on the signal changes on multiple receiving plates, the rotation angle of the shaft can be accurately determined, thus achieving low-cost, high-precision detection of the shaft rotation angle.
[0008] Additionally, the second surface includes: a first sub-surface and a second sub-surface located on different planes; wherein, a first distance between the first sub-surface and the receiving electrode is less than a second distance between the second sub-surface and the receiving electrode; and the second metal sheet covers the first sub-surface.
[0009] In addition, the area of the first sub-surface is the same as the area of the second metal sheet, and the first sub-surface and the second sub-surface together form a complete ring.
[0010] In addition, multiple receiving plates are arranged around the rotating shaft.
[0011] In addition, the central region of the support includes a through hole, the shape of which, together with the shape of the rotating shaft, forms a retaining structure, and the support rotates synchronously with the rotating shaft using the retaining structure.
[0012] In addition, the plurality of receiving plates form a ring structure, and any two receiving plates do not overlap in the axial direction.
[0013] In addition, the capacitive encoder also includes: a bearing disposed on the rotating shaft; the bearing is used to support the rotating shaft and constrain the displacement of the rotating shaft in the radial or axial direction.
[0014] In addition, the capacitive encoder also includes: a housing, on which a boss is provided, the boss being engaged with the end face of the bearing.
[0015] In addition, the capacitive encoder also includes: a fixing member fixed relative to the housing, a plurality of receiving plates disposed on the surface of the fixing member, the rotating shaft passing through the fixing member, and the plurality of receiving plates arranged around the rotating shaft. Attached Figure Description
[0016] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.
[0017] Figure 1 This is an exploded view of the capacitive encoder according to an embodiment of this solution;
[0018] Figure 2 This is a cross-sectional structural diagram of a capacitive encoder according to an embodiment of this solution;
[0019] Figure 3 This is a schematic diagram of the emitter plate in this embodiment of the solution;
[0020] Figure 4 This is a schematic diagram of the receiving electrode plate according to an embodiment of this solution;
[0021] Figure 5 This is a schematic diagram of the rotating shaft in this embodiment of the solution;
[0022] Figure 6 This is a structural schematic diagram of the metal component based on an embodiment of this solution;
[0023] Figure 7 This is a structural schematic diagram of the support component based on an embodiment of this solution;
[0024] Figure 8 This is a schematic diagram of the combined structure of the metal parts and the support parts in this embodiment of the solution;
[0025] Figure 9 This is a schematic diagram of another combination structure of metal parts and support parts according to an embodiment of this solution;
[0026] Figure 10 This is a schematic diagram of the equivalent structure of the transmitting electrode, the metal part, and the receiving electrode in the first state according to the embodiment of this solution;
[0027] Figure 11 This is a schematic diagram of the equivalent structure of the transmitting electrode, the metal part, and the receiving electrode in the second state according to the embodiment of this solution;
[0028] Figure 12 This is a schematic diagram of the rotation direction of the shaft according to an embodiment of this solution;
[0029] Figure 13 This is a schematic diagram showing the correspondence between the rotation angle and the capacitance value in this embodiment of the solution;
[0030] Figure 14 This is a three-dimensional structural diagram of the capacitive encoder according to an embodiment of this solution. Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the various embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this utility model to enable the reader to better understand this utility model. However, the technical solutions claimed by this utility model can be implemented even without these technical details and various changes and modifications based on the following embodiments.
[0032] The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this utility model. The various embodiments can be combined with or referenced by each other without contradiction.
[0033] The embodiments of this utility model relate to a capacitive encoder, such as... Figure 1 As shown, the capacitive encoder includes: a rotating shaft 1, a transmitting electrode 2, a receiving electrode 3, a support member 4 disposed between the transmitting electrode 2 and the receiving electrode 3, and a metal part 5 disposed on the support member 4; the transmitting electrode 2 and the receiving electrode 3 are arranged opposite to each other along the axial direction of the rotating shaft 1. The structure of the metal part 5 is as follows. Figure 6 As shown, the metal component 5 includes: a first metal sheet 51, a second metal sheet 52, and a connector 53 connecting the first metal sheet 51 and the second metal sheet 52; the first metal sheet 51 is disposed on the first surface of the support member 4 facing the transmitting electrode plate 2, and the second metal sheet 52 is disposed on the second surface of the support member 4 facing the receiving electrode plate 3, wherein the area of the first metal sheet 51 is larger than the area of the second metal sheet 52; there are multiple receiving electrodes 3, and the facing area between the second metal sheet 52 and at least one receiving electrode plate 3 changes during the rotation of the rotating shaft 1; the rotation angle of the rotating shaft 1 is determined according to the signal changes on the multiple receiving electrodes 3.
[0034] Compared to existing technologies, this embodiment of the invention features a capacitive encoder in which the transmitting and receiving plates are arranged opposite each other along the axis of the rotating shaft. A support and a metal component are placed between the transmitting and receiving plates to assist in the transmission of signals from the transmitting plate to the receiving plate. The metal component includes a first metal sheet, a second metal sheet, and a connector linking the first and second metal sheets. The first metal sheet is opposite to the transmitting plate, and the second metal sheet is opposite to the receiving plate. The area of the first metal sheet is larger than that of the second metal sheet. The larger area of the first metal sheet opposite to the transmitting plate facilitates the reception of more signals from the transmitting plate. When the shaft rotates by the same angle, the change in the capacitance signal generated by the capacitive structure is greater, thereby improving the detection sensitivity of the capacitive structure. Multiple receiving plates are used, and the facing area between the second metal sheet and at least one receiving plate changes during shaft rotation. Based on the signal changes on multiple receiving plates, the rotation angle of the shaft can be accurately determined, thus achieving low-cost, high-precision detection of the shaft rotation angle.
[0035] like Figure 2 The diagram shows a cross-sectional view of a capacitive encoder. The rotating shaft 1 is located at the center of the encoder. From bottom to top, the components are: a transmitting electrode 2, a support 4, a metal part 5 mounted on the support 4, and a receiving electrode 3. Figure 3 As shown, the emitter plate Tx is disposed on the surface of the base, and the emitter plate Tx can be a complete circle. Figure 4 As shown, multiple receiving plates (Rx1, Rx2, Rx3) are arranged around the rotating shaft, forming a circular structure, and no two receiving plates overlap in the direction of the shaft core. Additionally, the capacitive encoder includes a fixing member 31 fixed relative to the housing, with multiple receiving plates disposed on the surface of the fixing member 31. A through hole is present in the center of the fixing member 31 for the rotating shaft to pass through it, and the multiple receiving plates are arranged around the rotating shaft.
[0036] For absolute encoders, the number of receiving plates must be at least three, while for incremental encoders, the number of receiving plates can be two or more. Additionally, to prevent detection dead zones, the central angle of the fan-shaped second metal plate must be greater than the central angle of one receiving plate, but the central angle of the fan-shaped second metal plate must be smaller than the central angle formed by two adjacent receiving plates.
[0037] like Figure 5 As shown, a locking position 11 is provided at the support position of the rotating shaft. The central area of the support includes a through hole. The shape of the through hole and the shape of the locking position of the rotating shaft form a locking structure. The support rotates synchronously with the rotating shaft using the locking structure.
[0038] like Figure 6 The metal parts shown, and as Figure 7 The support component shown has through holes in its central area that match the shape of the pivot shaft, facilitating the installation of the metal component and the support component onto the pivot shaft. For example... Figure 6 The area of the first metal sheet 51 shown is larger than the area of the second metal sheet 52. The area of the first metal sheet matches the area of the emitting electrode to maximize the facing area between the first metal sheet and the emitting electrode, thereby maximizing the reception of signals from the emitting electrode and ensuring the signal quantity within the capacitor structure. The area of the second metal sheet 52 is related to the number and area of the receiving electrodes. The first metal sheet 51, the second metal sheet 52, and the connector 53 can be integrally formed. The metal part is generated from a complete metal sheet through punching, bending, etc., and then fixed to the surface of the support. A receiving area is provided at the location of the connector on the support to fix the connector. Alternatively, a conductive pattern of a specific shape can be engraved on the surface of the support using laser direct forming (LDS) to serve as the metal part. The effect after the metal part is fixed to the support is as follows. Figure 8 As shown, the edge of the metal part will not extend beyond the edge of the support.
[0039] In addition, such as Figure 9 As shown, the second surface of the support member 4 includes a first sub-surface and a second sub-surface located on different planes; wherein, the first distance between the first sub-surface and the receiving electrode is smaller than the second distance between the second sub-surface and the receiving electrode; the second metal sheet 52 covers the first sub-surface. This design can improve the overall sensitivity of the capacitor assembly. The area of the first sub-surface is the same as the area of the second metal sheet 52, and the first sub-surface and the second sub-surface together form a complete ring.
[0040] The following explains how a capacitive encoder detects rotation angle:
[0041] For ease of understanding, the annular emitting electrode, receiving electrode, and metal component are transformed into a planar equivalent structure. It is assumed that there are three receiving electrodes, each with the same area, and the second metal piece 52 is a semi-circular ring. The equivalent structure is then as follows: Figures 10 to 11 As shown, Figure 10 This diagram illustrates the relative positions of the transmitting plate, receiving plate, and metal component in the first state of a capacitive encoder. The transmitting plate Tx is positioned opposite to the first metal piece 51, and the receiving plates (Rx1, Rx2, Rx3) are positioned opposite to the second metal piece 52. The first metal piece 51 and the second metal piece 52 are connected by a connector 53. A diagram illustrating the relative positions of the transmitting plate, receiving plate, and metal component in the second state after the shaft has rotated is shown below. Figure 11As shown, the area of the emitting electrode Tx facing the first metal sheet 51 remains unchanged, and the area of at least one receiving electrode facing the second metal sheet 52 remains unchanged. Figure 11 As shown, the areas of Rx1, Rx2, Rx3, and the second metal sheet have all changed. Figure 12 As shown in the diagram, when the shaft rotates one full turn (360 degrees) counterclockwise, the capacitance values (C1, C2, C3) of the capacitors formed by the metal parts of the emitting electrode and Rx1, Rx2, and Rx3 change as follows: Figure 13 As shown, by Figure 13 It can be seen that the combination of C1, C2, and C3 is different under different rotation angles. That is, a unique rotation angle can be determined based on the values of C1, C2, and C3, and the detection result of the rotation angle can be accurately obtained.
[0042] When the second surface of the support member 4 includes a first sub-surface and a second sub-surface located on different planes, the area of the second sub-surface of the support member between the transmitting electrode and the receiving electrode can also form a capacitor. To increase the capacitance value formed by the area of the second sub-surface, the thickness of the support member in the area of the second sub-surface can be minimized. An increased capacitance value leads to an improved charge storage capacity of the capacitor structure. Under the premise that the transmitting electrode transmits the same amount of signal, the receiving electrode can generate a stronger detection signal with a higher charge storage capacity, thereby improving the sensitivity of the capacitor structure detection.
[0043] In addition, such as Figure 2 As shown, the capacitive encoder also includes: a bearing 6 mounted on the rotating shaft; the bearing supports the rotating shaft and constrains its radial or axial displacement. The capacitive encoder also includes: a housing 7, on which a boss is provided, the boss engaging with the end face of the bearing 6 to axially limit the bearing.
[0044] like Figure 14 The diagram shows a three-dimensional structure of a capacitive encoder. The rotating shaft 1 protrudes from the edge of the outer casing 7. The protruding rotating shaft is connected to the motor through a coupling to achieve synchronous rotation with the motor.
[0045] By using metal components to detect rotation direction, the metal components do not need to be electrically connected to the circuit board and are independent structures. Therefore, the rotation of the metal components is more flexible, and 360-degree detection of the shaft can be achieved. There is no need to consider wiring issues and perform additional reset operations, which improves the flexibility of rotation detection.
[0046] Another feasible embodiment of this utility model relates to an electronic device, including the capacitive encoder as described above. The capacitive encoder is used in conjunction with a motor to detect the motor's operating status.
[0047] Compared with related technologies, the electronic device provided in this embodiment of the present invention is equipped with the capacitive encoder provided in the aforementioned embodiments. Therefore, it also has the technical effects provided in the aforementioned embodiments, and will not be described in detail here.
[0048] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.
Claims
1. A capacitive encoder, characterized in that, Includes: a rotating shaft, a transmitting electrode plate, a receiving electrode plate, a support member disposed between the transmitting electrode plate and the receiving electrode plate, and a metal part disposed on the support member; The transmitting electrode and the receiving electrode are arranged opposite each other along the axis of the rotating shaft; The metal component includes: a first metal sheet, a second metal sheet, and a connector connecting the first metal sheet and the second metal sheet; The first metal sheet is disposed on the first surface of the support member facing the transmitting electrode plate, and the second metal sheet is disposed on the second surface of the support member facing the receiving electrode plate, wherein the area of the first metal sheet is larger than the area of the second metal sheet. The number of receiving electrodes is multiple, and the facing area between the second metal sheet and at least one of the receiving electrodes changes during the rotation of the shaft. The rotation angle of the shaft is determined based on the signal changes on the multiple receiving plates.
2. The capacitive encoder according to claim 1, characterized in that, The second surface includes: a first sub-surface and a second sub-surface located on different planes; wherein, a first distance between the first sub-surface and the receiving electrode is less than a second distance between the second sub-surface and the receiving electrode; The second metal sheet covers the first sub-surface.
3. The capacitive encoder according to claim 2, characterized in that, The area of the first sub-surface is the same as the area of the second metal sheet, and the first sub-surface and the second sub-surface together form a complete ring.
4. The capacitive encoder according to claim 1, characterized in that, Multiple receiving plates are arranged around the rotating shaft.
5. The capacitive encoder according to claim 4, characterized in that, The central region of the support includes a through hole, the shape of which, together with the shape of the rotating shaft, forms a retaining structure, and the support rotates synchronously with the rotating shaft using the retaining structure.
6. The capacitive encoder according to claim 1, characterized in that, The plurality of receiving plates form a ring structure, and any two receiving plates do not overlap in the axial direction.
7. The capacitive encoder according to claim 1, characterized in that, Also includes: The bearing is mounted on the shaft; The bearing is used to support the shaft and constrain the shaft's displacement in the radial or axial direction.
8. The capacitive encoder according to claim 7, characterized in that, Also includes: The outer casing has a boss that engages with the end face of the bearing.
9. The capacitive encoder according to claim 8, characterized in that, Also includes: A fixing member is fixed relative to the outer shell, a plurality of receiving electrodes are disposed on the surface of the fixing member, the rotating shaft passes through the fixing member, and the plurality of receiving electrodes are arranged around the rotating shaft.
10. An electronic device, characterized in that, include: The capacitive encoder as described in any one of claims 1 to 9.