Capacitive encoders, electronic devices

Abstract

This application relates to the field of encoders and discloses a capacitive encoder and an electronic device. The capacitive encoder includes: a rotating shaft, a first moving pole plate fixed relative to the rotating shaft, a housing, and a first fixed pole plate fixed relative to the housing; the first fixed pole plate includes: a first pole plate and a second pole plate, which are symmetrically arranged with respect to the plane containing the first moving pole plate; during the rotation of the rotating shaft, the facing area between the first moving pole plate and the first pole plate changes, and the facing area between the first moving pole plate and the second pole plate also changes; the first moving pole plate and the first pole plate constitute a first detection capacitor, and the first moving pole plate and the second pole plate constitute a second detection capacitor; the sum of the capacitance values ​​of the first detection capacitor and the second detection capacitor is used to determine the rotation angle of the rotating shaft, thereby effectively reducing the angle detection error caused by tilting or axial movement of the rotating shaft during assembly or operation, and improving the angle detection accuracy.

Description

Technical Field

[0001] This application relates to the field of encoders, and more particularly to a capacitive encoder and electronic equipment. 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. 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; therefore, it is difficult to balance cost and accuracy in photoelectric encoders. Electromagnetic encoders are susceptible to external magnetic interference, affecting their accuracy. Furthermore, regardless of the type of encoder, there is always the possibility of the shaft tilting relative to the housing, or axial movement, affecting the accuracy of angle detection. Therefore, the industry needs an encoder structure that balances accuracy and cost. Summary of the Invention

[0003] The purpose of this application is to provide a capacitive encoder and electronic device. Based on a high-precision, low-cost capacitive encoder, the device synchronously detects angles by using a first pole plate and a second pole plate that are symmetrically arranged relative to the plane of the first moving pole plate. The rotation angle of the shaft is determined by the sum of the first detection capacitor formed by the first moving pole plate and the first pole plate, and the second detection capacitor formed by the first moving pole plate and the second pole plate. This can effectively reduce the angle detection error caused by the tilting or axial movement of the shaft during assembly or operation, and improve the angle detection accuracy.

[0004] To address the aforementioned technical problems, embodiments of this application provide a capacitive encoder, comprising: a rotating shaft, a first movable pole plate fixed relative to the rotating shaft, a housing, and a first fixed pole plate fixed relative to the housing; the first fixed pole plate includes: a first pole plate and a second pole plate, the first pole plate and the second pole plate being symmetrically arranged with respect to the plane containing the first movable pole plate; during the rotation of the rotating shaft, the facing area between the first movable pole plate and the first pole plate changes, and the facing area between the first movable pole plate and the second pole plate also changes; the first movable pole plate and the first pole plate constitute a first detection capacitor, the first movable pole plate and the second pole plate constitute a second detection capacitor, and the sum of the capacitance values ​​of the first detection capacitor and the second detection capacitor is used to determine the rotation angle of the rotating shaft.

[0005] Embodiments of this application also provide an electronic device including the capacitive encoder described above.

[0006] Compared with the prior art, this application embodiment provides a first movable electrode plate fixed relative to the rotating shaft and a first fixed electrode plate fixed relative to the outer shell. The first fixed electrode plate includes a first electrode plate and a second electrode plate symmetrically arranged with respect to the plane of the first movable electrode plate. During the rotation of the rotating shaft, the facing area between the first movable electrode plate and the first electrode plate changes, and the facing area between the first movable electrode plate and the second electrode plate also changes. The first movable electrode plate and the first electrode plate constitute a first detection capacitor, and the first movable electrode plate and the second electrode plate constitute a second detection capacitor. When the rotating shaft tilts or moves axially, the change in distance between the first movable electrode plate and the first electrode plate is approximately the same as the change in distance between the first movable electrode plate and the second electrode plate. By summing the capacitance values ​​of the first detection capacitor and the second detection capacitor, the influence of the change in distance between the electrodes on the angle detection result can be largely eliminated, thereby effectively reducing the angle detection error caused by the tilting or axial movement of the rotating shaft during assembly or operation, and improving the angle detection accuracy.

[0007] In addition, the first pattern of the first electrode plate is: a ring composed of multiple first fan rings, with adjacent first fan rings spaced apart; the first projection of the first moving electrode plate onto the plane where the first electrode plate is located covers the positions of at least two first fan rings, and the first projection does not cover the positions of all first fan rings.

[0008] In addition, the first moving electrode plate includes a third electrode plate and a fourth electrode plate spaced apart, and a connector connecting the third electrode plate and the fourth electrode plate; the second pattern of the third electrode plate is a centrally symmetrical pattern composed of N third fan rings, where N is an integer greater than 1, and the N third fan rings are electrically connected to each other; the fourth electrode plate has the same pattern as the third electrode plate; the first fan rings are divided into several groups, and the patterns formed by the first fan rings in each group are rotationally symmetrical to each other, and the number of first fan rings in each group is N; the capacitive encoder also includes a second fixed electrode plate fixed relative to the housing, and a second moving electrode plate fixed relative to the rotating shaft; the surface of the second fixed electrode plate is equally divided into N regions, and each region is formed by a metal sheet forming a different third pattern; the second moving electrode plate is arranged opposite to the second fixed electrode plate, and the second moving electrode plate and the metal sheet form a second capacitor, and a digital signal is determined based on the second capacitor; the sum of the capacitance values ​​of the first detection capacitor and the second detection capacitor, and the digital signal are used to determine the rotation angle of the rotating shaft.

[0009] In addition, the third pattern corresponding to the region is: a pattern corresponding to concentric fourth fan rings with different outer radii, or a pattern corresponding to a combination of concentric fourth fan rings with different outer radii, or a blank pattern.

[0010] In addition, the capacitive encoder further includes: a third moving electrode plate fixed relative to the rotating shaft, and a third fixed electrode plate fixed relative to the housing; the third moving electrode plate and the third fixed electrode plate constitute a third detection capacitor, and the change trend of the capacitance signal of the third detection capacitor is the same as the change trend of the capacitance signal of the first detection capacitor; the sum of the capacitance values ​​of the first detection capacitor, the second detection capacitor and the third detection capacitor is used to determine the rotation angle of the rotating shaft.

[0011] In addition, the capacitive encoder further includes: a fixing member fixed to the housing, the fixing member including: a first surface facing the first moving pole plate and a second surface facing the third moving pole plate; the second pole plate is disposed on the first surface and the third fixed pole plate is disposed on the second surface; the fixing member further includes: a grounding member, the grounding member being located between the second pole plate and the third fixed pole plate, the grounding member being used to isolate the electric field between the second pole plate and the third fixed pole plate.

[0012] In addition, the capacitive encoder further includes: a support member fixed relative to the rotating shaft; the support member includes: a third surface facing the first pole plate and a fourth surface facing the second pole plate; the first moving pole plate includes: a third pole plate disposed on the third surface and a fourth pole plate disposed on the fourth surface, the third pole plate and the fourth pole plate being electrically connected.

[0013] Additionally, the rotating shaft includes a retaining portion; the supporting member includes a through hole that matches the shape of the retaining portion; the rotating shaft passes through the supporting member through the through hole, and the retaining portion contacts the through hole, the retaining portion and the through hole cooperating with each other to make the supporting member and the rotating shaft rotate synchronously.

[0014] 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. Attached Figure Description

[0015] 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.

[0016] Figure 1 This is an exploded view of the capacitive encoder according to an embodiment of this solution;

[0017] Figure 2 This is a cross-sectional structural diagram of a capacitive encoder according to an embodiment of this solution;

[0018] Figure 3 This is a schematic diagram of the structure of the first pole plate of the capacitive encoder in this embodiment of the solution;

[0019] Figure 4 This is a schematic diagram of the structure of the second pole plate of the capacitive encoder according to an embodiment of this solution;

[0020] Figure 5 This is a schematic diagram of the structure of the first pole plate and the first moving pole plate of the capacitive encoder according to the embodiment of this solution;

[0021] Figure 6 This is a schematic diagram of the equivalent structure of a capacitive encoder according to an embodiment of this solution;

[0022] Figure 7 This is a schematic diagram of the equivalent structure of the capacitive encoder under axial movement state in this embodiment of the solution;

[0023] Figure 8 This is a schematic diagram of the equivalent structure of the capacitive encoder in the tilt state according to the embodiment of this solution;

[0024] Figure 9 This is a schematic diagram of the changes in the various capacitor signals in the capacitive encoder according to an embodiment of this solution;

[0025] Figure 10 This is an exploded view of the capacitive encoder according to another embodiment of this solution;

[0026] Figure 11 This is a schematic diagram of the structure of the first moving pole plate of the capacitive encoder according to another embodiment of this solution;

[0027] Figure 12 This is a schematic diagram of the structure of the first pole plate of a capacitive encoder according to another embodiment of this solution;

[0028] Figure 13 This is a schematic diagram of the structure of the second stationary plate of the capacitive encoder according to another embodiment of this solution;

[0029] Figure 14 This is a structural schematic diagram of a capacitive encoder in a digital signal 00 state according to another embodiment of this solution;

[0030] Figure 15 This is a structural schematic diagram of a capacitive encoder under a digital signal 11 state according to another embodiment of this solution;

[0031] Figure 16 This is a structural schematic diagram of a digital signal 10 state of a capacitive encoder according to another embodiment of this solution;

[0032] Figure 17This is a structural schematic diagram of a capacitive encoder in a digital signal 01 state according to another embodiment of this solution;

[0033] Figure 18 This is an exploded view of the capacitive encoder according to another embodiment of the present solution;

[0034] Figure 19 This is a schematic diagram of the equivalent structure of a capacitive encoder according to another embodiment of this solution;

[0035] Figure 20 This is a structural schematic diagram of the support member and the first moving pole plate of the capacitive encoder according to an embodiment of this solution;

[0036] Figure 21 This is a schematic diagram of the structure of the rotating shaft of the capacitive encoder according to an embodiment of this solution;

[0037] Figure 22 This is a structural schematic diagram of another support component and the first moving pole plate of the capacitive encoder according to an embodiment of this solution.

[0038] Figure label:

[0039] 1-Spindle; 12-Clamping part;

[0040] 2-Outer shell;

[0041] 31-First moving electrode plate; 32-Second moving electrode plate; 33-Third moving electrode plate; 310-Support member; 311-Third electrode plate; 312-Fourth electrode plate; 313-Connector; 3101-Through hole; 3102-Groove; 3111-Third fan ring; 3121-Fourth fan ring;

[0042] 41-First stationary plate; 42-Second stationary plate; 43-Third stationary plate; 411-First plate; 412-Second plate; 421-Metal sheet; 430-Fixed component; 431-Fifth plate; 432-Sixth plate;

[0043] 6-Grounding component;

[0044] 7-Bearing. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application 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 presented in the various embodiments of this application to enable readers to better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0046] The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0047] Embodiments of this application relate to a capacitive encoder, such as... Figure 1 and Figure 2 As shown, it includes: a rotating shaft 1, a first moving electrode 31 fixed relative to the rotating shaft 1, a housing 2, and a first fixed electrode 41 fixed relative to the housing; the first fixed electrode 41 includes: a first electrode 411 and a second electrode 412, the first electrode 411 and the second electrode 412 being symmetrically arranged with respect to the plane containing the first moving electrode 31; during the rotation of the rotating shaft 1, the facing area of ​​the first moving electrode 31 and the first electrode 411 changes, and the facing area of ​​the first moving electrode 31 and the second electrode 412 also changes; the first moving electrode 31 and the first electrode 411 constitute a first detection capacitor, the first moving electrode 31 and the second electrode 412 constitute a second detection capacitor, and the sum of the capacitance values ​​of the first detection capacitor and the second detection capacitor is used to determine the rotation angle of the rotating shaft.

[0048] Compared with the prior art, this application embodiment provides a first moving electrode plate fixed relative to the rotating shaft and a first fixed electrode plate fixed relative to the outer shell. The first fixed electrode plate includes a first electrode plate and a second electrode plate symmetrically arranged with respect to the plane of the first moving electrode plate. During the rotation of the rotating shaft, the facing area between the first moving electrode plate and the first electrode plate changes, and the facing area between the first moving electrode plate and the second electrode plate also changes. The first moving electrode plate and the first electrode plate constitute a first detection capacitor, and the first moving electrode plate and the second electrode plate constitute a second detection capacitor. When the rotating shaft tilts or moves axially, the change in distance between the first moving electrode plate and the first electrode plate is approximately the same as the change in distance between the first moving electrode plate and the second electrode plate. By summing the first detection capacitor and the second detection capacitor, the influence of the change in distance between the electrodes on the angle detection result can be largely eliminated, thereby effectively reducing the angle detection error caused by the tilting or axial movement of the rotating shaft during assembly or operation, and improving the angle detection accuracy.

[0049] The detection principles of the first and second detection capacitors can be referenced from those of a parallel plate capacitor. The physical formula for a parallel plate capacitor is: C = εS / 4πkd; where ε represents the dielectric constant of the medium, determined by the medium between the plates, such as air or water; k represents the electrostatic constant, also known as the Coulomb constant, which indicates that the force between two point charges, each with a charge of 1C, separated by a distance of 1m in a vacuum is 8.987551 × 10⁻⁶. 9 N, i.e., k = 8.987551 × 10 9 N·m 2 / C; S represents the area (projected area) of the two plates facing each other; d represents the perpendicular distance between the two plates; π represents pi. The first moving plate and the first plate in the first detection capacitor serve as the two plates in the above physical formula, and the first moving plate and the second plate in the second detection capacitor serve as the two plates in the above physical formula. When the shaft rotates, the first moving plate rotates synchronously with the shaft, changing the area of ​​the first moving plate facing the first plate, thus causing a corresponding change in the capacitance value of the first detection capacitor. Similarly, the area of ​​the first moving plate facing the second plate changes, causing a corresponding change in the capacitance value of the second detection capacitor. Since the changes in the area of ​​the first moving plate facing the first plate, and the changes in the area of ​​the first moving plate facing the second plate, are both related to the rotation angle of the shaft, the rotation angle of the shaft can be determined based on the capacitance value of either the first or second detection capacitor.

[0050] The detection of different rotation angles of the shaft can be achieved by designing the first pattern of the first electrode plate. To achieve 360-degree detection of the shaft, such as... Figure 3 As shown, the first pattern of the first electrode plate is a ring composed of multiple first sector rings, with adjacent first sector rings spaced apart. Since the second electrode plate and the first electrode plate are planar symmetrical figures, the pattern of the second electrode plate is consistent with the first pattern of the first electrode plate, as shown below. Figure 4 As shown, the pattern of the first electrode plate is: a ring composed of multiple second sector rings, with adjacent second sector rings spaced apart. Figure 5 The diagram shows the combined structure of the first electrode plate and the first moving electrode plate. The first projection of the first moving electrode plate 31 onto the plane of the first electrode plate covers the positions of at least two first sector rings, but the first projection does not cover the positions of all the first sector rings. The positional design between the first electrode plate and the first moving electrode plate ensures that the facing area between the first moving electrode plate and at least one first sector ring changes during the rotation of the shaft, thereby ensuring that the capacitance generated between the first moving electrode plate and the first electrode plate changes, thus obtaining a uniquely determined rotation angle.

[0051] Under normal circumstances, during the rotation of the shaft, the distance between the first moving plate and the second moving plate remains constant, and the distance between them also remains constant. To facilitate a quantitative description of the principle, the annular structure of the first and second moving plates can be cut along the radius and then unfolded, as shown below. Figure 6The equivalent structure is shown. Assume the distance between the first moving electrode plate and the distance between the first moving electrode plate and the second electrode plate are both d0. The first sector rings in the first electrode plate 411 are represented as Rx1_1, Rx2_1, and Rx3_1, respectively. The second sector rings of the second electrode plate 412 corresponding to the first sector rings are represented as Rx1_2, Rx2_2, and Rx3_2, respectively. The rotation direction of the first moving electrode plate 31 between the first electrode plate 411 and the second electrode plate 412 is equivalent to... Figure 6 The equivalent direction of movement shown is as follows: Figure 6 In the state shown, the projection of the first moving electrode 31 toward the first electrode 411 completely covers Rx1_1, and the projection of the first moving electrode 31 toward the first electrode 411 partially covers Rx1_1. Figure 6 When the plate moves to the right as shown, the area between the first moving plate 31 and Rx1_1 decreases, while the area between the first moving plate 31 and Rx2_1 increases (x becomes larger). Therefore, the capacitances formed by the first moving plate 31 and Rx1_1 and the first moving plate 31 and Rx2_1 both change. Similarly, when the first moving plate 31 moves towards... Figure 6 When the right side moves as shown, the capacitance formed by the first moving plate 31 and Rx1_2 and the capacitance formed by the first moving plate 31 and Rx2_2 both change.

[0052] However, when the shaft moves axially or tilts relative to the outer casing, the distance between the first moving electrode plate and the distance between the first moving electrode plate and the second moving electrode plate may change.

[0053] like Figure 7 As shown, this illustrates a situation where the rotating shaft exhibits axial movement relative to the outer casing. Compared to the normal state, the first moving electrode plate is closer to the first electrode plate, meaning the distance between the first moving electrode plate 31 and the first electrode plate 411 decreases, resulting in a larger first detection capacitor. Simultaneously, the distance between the first moving electrode plate and the second electrode plate 412 increases, causing a smaller second detection capacitor. By summing the capacitance values ​​of the first and second detection capacitors, the influence of the change in distance between the electrodes on the angle detection result can be largely eliminated, thereby reducing the impact of axial movement.

[0054] like Figure 8 As shown, the shaft is tilted relative to the outer casing. The first moving plate forms an angle with the first plate. The change in the average distance between the first moving plate 31 and the first plate 411 is approximately the same as the change in the average distance between the first moving plate and the second plate 412. Therefore, by summing the capacitance values ​​of the first detection capacitor and the second detection capacitor, the influence of the change in distance between the plates on the angle detection result can be largely eliminated, thereby reducing the impact of tilt.

[0055] like Figures 6 to 8As shown, the first electrode plate is composed of three first sector rings Rx1_1, Rx2_1, and Rx3_1, and the second electrode plate is composed of three second sector rings Rx1_2, Rx2_2, and Rx3_2. The first moving electrode plate and Rx1_1 form a first detection capacitor C1_1, and the first moving electrode plate and Rx1_2 form a second detection capacitor C1_2. C1 is obtained by summing C1_1 and C1_2. Similarly, C2 can be obtained based on the first moving electrode plate, Rx2_1, and Rx2_2, and C3 can be obtained based on the first moving electrode plate, Rx3_1, and Rx3_2. (The rest of the text appears to be a continuation of the previous paragraph.) Figure 6 The state shown is taken as the 0-degree rotation axis state, and we can obtain, as follows: Figure 9 The capacitance trends of C1, C2, and C3 are shown when the shaft rotates 360 degrees. From the capacitance trend, it can be observed that the calculated capacitance value greatly reduces the impact of improper shaft assembly or operation.

[0056] Another embodiment of this application relates to a capacitive encoder. Based on the above embodiments, the capacitive encoder in this embodiment can determine several angles corresponding to the rotation angle in each cycle through periodically changing analog signals, and then determine the cycle in which the rotation angle is located based on digital signals. The final angle detection is achieved by combining digital signals and analog signals.

[0057] like Figure 10 As shown, the first moving pole plate 31 in the capacitive encoder includes a third pole plate 311 and a fourth pole plate 312 spaced apart, and a connector 313 connecting the third pole plate 311 and the fourth pole plate 312. Figure 11 As shown, the second pattern of the third electrode plate 311 is a centrally symmetrical pattern composed of N third sector rings 3111, where N is an integer greater than 1. The N third sector rings are electrically connected to each other, and the positions where the third sector rings are electrically connected can be the inner arc positions of the third sector rings. Since the inner radii of the N third sector rings are equal, the conductors electrically connected by the N third sector rings form a circle with the inner radius of the third sector ring as the radius. The fourth electrode plate has the same pattern as the third electrode plate, and the pattern of the fourth electrode plate 312 is a centrally symmetrical pattern composed of N fourth sector rings 3121.

[0058] The first sector is divided into several groups, and the shapes formed by the first sector in each group are all rotationally symmetric to each other, with N first sector rings in each group. For example... Figure 12 The diagram shows the pattern of the first electrode plate when N equals 4. The first sector rings are divided into three groups: Rx1, Rx2, and Rx3. Each group contains four first sector rings, arranged in the following order: Rx1, Rx2, and Rx3. When the shaft rotates 360 degrees, the first electrode plates arranged in this order... Figure 11The capacitor formed by the first moving plate shown can generate a periodic analog signal with a 90-degree phase difference. Based on the value of the analog signal, four rotation angles of the rotating shaft with a 90-degree phase difference can be obtained, such as 0 degrees, 90 degrees, 180 degrees, and 270 degrees. At this point, several angles corresponding to each cycle can be determined based on the analog signal. However, a unique rotation angle needs to be determined from these several angles corresponding to each cycle based on the structure of the digital signal.

[0059] like Figure 10 As shown, the structure of the digital signal includes: a second fixed electrode plate 42 fixed relative to the outer casing 2, and a second moving electrode plate 32 fixed relative to the rotating shaft 1. Figure 13 As shown, the surface of the second stationary plate 42 is equally divided into N regions (e.g., Figure 13 As shown in Q1, Q2, Q3, and Q4, each region is formed by metal sheets 421 into a different third pattern. A second moving electrode plate is positioned opposite to a second fixed electrode plate, and the second moving electrode plate and the metal sheets constitute a second capacitor. A digital signal is determined based on this second capacitor. Since the second moving electrode plate rotates to different regions and forms different digital signals with the corresponding metal sheets, and the N regions correspond one-to-one with the N periods in the analog signal, the rotation angle of the shaft can be determined by using the different digital signals, thus identifying a unique rotation angle. The rotation angle of the shaft can be determined by using the sum of the capacitance values ​​of the first and second detection capacitors as the analog signal, combined with the digital signal.

[0060] The third pattern corresponding to each region of the second stationary plate is: a pattern corresponding to concentric fourth sector rings with different outer radii, or a pattern corresponding to a combination of concentric fourth sector rings with different outer radii, or a blank pattern. For example... Figure 13 As shown, Q1 corresponds to a blank pattern, and Q2 corresponds to the pattern formed by the combination of two concentric fourth sector rings with different outer radii. Figure 13 The pattern shown is a combination of Rx4 and Rx5. Q3 corresponds to the pattern of the fourth fan ring with the larger outer radius. Figure 13 As shown in Rx5), Q4 corresponds to the pattern of the fourth sector ring with the smaller outer radius ( Figure 13 (As shown in Rx4). This results in different digital signals obtained by the second moving electrode when it rotates to different regions. The fourth sector rings (metal sheets) in the second fixed electrode are spaced apart.

[0061] like Figure 14 As shown, when the second moving electrode 32 rotates to region Q1, there is neither Rx4 nor Rx5 in Q1, and the corresponding digital signal is 00; Figure 15 As shown, when the second moving electrode 32 rotates to region Q2, Q2 contains Rx4 and Rx5, and the corresponding digital signal at this time is 11; as Figure 16As shown, when the second moving electrode 32 rotates to region Q3, there is Rx5 in Q3, and the corresponding digital signal is 10; as Figure 17 As shown, when the second moving plate 32 rotates to region Q4, there is Rx4 within Q4, and the corresponding digital signal is 01. The aforementioned digital signal reflects whether the capacitance signals formed by the second moving plate, Rx4, and Rx5 are high-order or low-order signals. The second moving plate and Rx4 form capacitance C4, and the second moving plate and Rx5 form capacitance C5. When the area directly opposite the second moving plate and Rx4 is large, C4 is correspondingly larger. When C4 is greater than a set threshold, C4 can be considered a high-order signal; otherwise, it is a low-order signal. Similarly, when the area directly opposite the second moving plate and Rx5 is large, C5 is correspondingly larger. When C5 is greater than a set threshold, C5 can be considered a high-order signal; otherwise, it is a low-order signal.

[0062] The structure of the digital signal matches the structure of the analog signal, that is, the distribution of each region in the second fixed plate matches the period of the analog signal generated by the first plate.

[0063] In this embodiment, all Rx1 rings are connected to the same Rx1 receiving plate pin on the circuit board, and similarly, all Rx2 rings are connected to the same Rx2 receiving plate pin on the circuit board. Rx3, Rx4, and Rx5 are connected in the same way. Compared to a structure where each sector ring needs to be connected to a pin, the shared pin method in this embodiment allows for more sector rings to be set up with a fixed number of pins on the circuit board, thereby improving detection accuracy. For example, with three receiving plate pins, a structure where each sector ring needs to be connected to a pin can only set up sector rings with three receiving plates, while the shared pin scheme in this embodiment can set up 3×N sector rings, significantly improving the detection accuracy of the rotation angle.

[0064] Another embodiment of this application relates to a capacitive encoder, which, based on the above embodiments, improves the detection performance of rotation angle by additionally setting one or more sets of detection structures in the axial direction.

[0065] like Figure 18 As shown, the capacitive encoder further includes: a third moving electrode plate 33 fixed relative to the rotating shaft 1, and a third fixed electrode plate 43 fixed relative to the housing 2; the third moving electrode plate 33 and the third fixed electrode plate 43 constitute a third detection capacitor, and the changing trend of the capacitance signal of the third detection capacitor is the same as the changing trend of the capacitance signal of the first detection capacitor; the sum of the capacitance values ​​of the first detection capacitor, the second detection capacitor, and the third detection capacitor is used to determine the rotation angle of the rotating shaft. Since the changing trend of the capacitance signal of the third detection capacitor is the same as the changing trend of the capacitance signal of the first detection capacitor, when the rotating shaft rotates by the same angle, the change in the sum of the capacitance values ​​of the first detection capacitor, the second detection capacitor, and the third detection capacitor is greater, and the sensitivity of detecting the rotation angle is higher.

[0066] like Figure 18 As shown, the third fixed electrode plate 43 includes a fifth electrode plate 431 and a sixth electrode plate 432, which are symmetrically arranged with respect to the plane containing the third moving electrode plate 33. During the rotation of the shaft 1, the facing area of ​​the third moving electrode plate 33 and the fifth electrode plate 431 changes, and the facing area of ​​the third moving electrode plate 33 and the sixth electrode plate 432 also changes. The sum of the capacitance formed by the third moving electrode plate and the fifth electrode plate and the capacitance formed by the third moving electrode plate and the sixth electrode plate serves as the third detection capacitor. This third detection capacitor can effectively reduce the angle detection error caused by the tilting or axial movement of the shaft during assembly or operation.

[0067] like Figure 18 As shown, the capacitive encoder also includes a fixing member 430 fixed to the housing. The fixing member 430 includes a first surface facing the first moving pole plate 31 and a second surface facing the third moving pole plate 33. The second pole plate is disposed on the first surface, and the third fixed pole plate is disposed on the second surface. When the third fixed pole plate 43 includes a fifth pole plate 431 and a sixth pole plate 432, the fifth pole plate 431 can be disposed on the second surface, and the sixth pole plate 432 can be disposed in another spatial region symmetrical to the third moving pole plate 33.

[0068] The equivalent structures of the first moving plate, the first stationary plate, the third moving plate, and the third stationary plate are as follows: Figure 19 As shown, based on the capacitor detection structure composed of the first moving electrode 31, the first electrode 411, and the second electrode 412, an additional third moving electrode 33 and a fifth electrode 431 (as shown) are added axially. Figure 19 The Rx1_3, Rx2_3, Rx3_3 shown) and the sixth electrode plate 432 (as shown) Figure 19 The capacitor detection structure consisting of Rx1_4, Rx2_4, and Rx3_4 shown has a grounding component 6 between the second plate 412 and the fifth plate 431 when the second plate 412 and the fifth plate 431 are both mounted on the fixing member. The grounding component is used to isolate the electric field between the second plate 412 and the fifth plate 431 and avoid signal crosstalk.

[0069] To further improve detection performance, if there is sufficient axial space, several more sets of capacitive detection structures consisting of moving and fixed plates can be added axially.

[0070] Additionally, if the fixing component is used to fix the second and third stationary plates, it also includes a grounding component located between the second and third stationary plates. The grounding component isolates the electric field between the second and third stationary plates. A circular through hole is provided in the central area of ​​the fixing component to facilitate the passage of the rotating shaft, ensuring that the shaft does not come into contact with the fixing component during rotation.

[0071] The implementation details in the above embodiments can be combined with each other. For example, while reducing the angle detection error caused by the tilting or axial movement of the shaft during assembly or operation, the detection accuracy can be improved by combining analog and digital signal detection methods. While reducing the angle detection error caused by the tilting or axial movement of the shaft during assembly or operation, the detection sensitivity can be improved by setting multiple sets of capacitor detection structures. Alternatively, based on the detection method combining analog and digital signals, multiple sets of analog signal capacitor detection structures can be set to improve the detection sensitivity. Alternatively, the detection method combining analog and digital signals can be implemented separately. When implementing the detection method combining analog and digital signals separately, a single first detection capacitor or a single second detection capacitor can be used as the analog signal. When using only the first detection capacitor, only the corresponding structure of the first detection capacitor needs to be set, omitting the setting of the corresponding structure of the second detection capacitor.

[0072] Additionally, this applies to all the embodiments described above, such as Figure 20 As shown, the capacitive encoder also includes: a support member 310 fixed relative to the rotating shaft 1; the support member 310 includes: a third surface facing the first pole plate and a fourth surface facing the second pole plate; the first moving pole plate 31 includes: a third pole plate 311 disposed on the third surface and a fourth pole plate 312 disposed on the fourth surface, the third pole plate 311 and the fourth pole plate 312 being electrically connected, specifically, the third pole plate 311 and the fourth pole plate 312 can be electrically connected by a connector 313.

[0073] In addition, such as Figure 21 As shown, the rotating shaft 1 includes a retaining part 12. (As indicated...) Figure 20 As shown, the support member 310 includes a through hole 3101 that matches the shape of the retaining part 12; the rotating shaft 1 passes through the support member 310 via the through hole 3101, and the retaining part 12 contacts the through hole 3101, the retaining part 12 and the through hole 3101 cooperating with each other to make the support member 310 and the rotating shaft 1 rotate synchronously. Figures 20 to 21 As shown, the shape of the retaining part is semi-cylindrical, and the outline of the through hole is also semi-cylindrical with the same radius. The through hole can be slightly larger than the shape of the retaining part to ensure that the retaining part can be completely accommodated by the through hole.

[0074] The shape of the support member 310 can be as follows Figure 20 The image shown is a portion of a circle, and can also be viewed as follows: Figure 22 The shape shown is a complete circle. A groove 3102 is also provided on the support member 310, the position of which corresponds to the position of the connector 313, and the groove 3102 is used to accommodate the connector 313.

[0075] In addition, such as Figure 2As shown, the capacitive encoder also includes a bearing 7 disposed on the rotating shaft 1; the bearing 7 is used to support the rotating shaft 1 and constrain the displacement of the rotating shaft 1 in the radial or axial direction.

[0076] Another feasible embodiment of this application relates to an electronic device, including a capacitive encoder as described above.

[0077] Compared with related technologies, the electronic device provided in this application embodiment is equipped with the capacitive encoder provided in the aforementioned embodiment. Therefore, it also has the technical effects provided in the aforementioned embodiment, and will not be described in detail here.

[0078] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing this application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of this application.

Claims

1. A capacitive encoder, characterized in that, include: A rotating shaft, a first moving electrode plate fixed relative to the rotating shaft, a housing, and a first fixed electrode plate fixed relative to the housing; The first fixed electrode plate includes: a first electrode plate and a second electrode plate, wherein the first electrode plate and the second electrode plate are symmetrically arranged with respect to the plane in which the first moving electrode plate is located; During the rotation of the shaft, the area of ​​the first moving electrode plate facing the second electrode plate changes, and the area of ​​the first moving electrode plate facing the second electrode plate also changes. The first moving electrode and the first electrode plate together constitute a first detection capacitor, and the first moving electrode and the second electrode plate together constitute a second detection capacitor. The sum of the capacitance values ​​of the first detection capacitor and the second detection capacitor is used to determine the rotation angle of the rotating shaft. The capacitive encoder further includes: a third moving pole plate fixed relative to the rotating shaft, and a third fixed pole plate fixed relative to the housing; The third moving plate and the third fixed plate constitute a third detection capacitor, and the change trend of the capacitance signal of the third detection capacitor is the same as the change trend of the capacitance signal of the first detection capacitor. The sum of the capacitance values ​​of the first detection capacitor, the second detection capacitor, and the third detection capacitor is used to determine the rotation angle of the rotating shaft.

2. The capacitive encoder according to claim 1, characterized in that, The first pattern of the first electrode plate is: a ring composed of multiple first fan rings, with adjacent first fan rings spaced apart; The first projection of the first moving electrode plate onto the plane where the first electrode plate is located covers at least two of the locations of the first fan rings, but the first projection does not cover all the locations of the first fan rings.

3. The capacitive encoder according to claim 2, characterized in that, The first moving electrode plate includes a third electrode plate and a fourth electrode plate spaced apart, and a connector connecting the third electrode plate and the fourth electrode plate; the second pattern of the third electrode plate is a centrally symmetrical pattern composed of N third fan rings, where N is an integer greater than 1, and the N third fan rings are electrically connected to each other; the fourth electrode plate has the same pattern as the third electrode plate. The first sector ring is divided into several groups on average. The shapes formed by the first sector rings in each group are rotationally symmetric to each other, and the number of the first sector rings in each group is N. The capacitive encoder further includes: a second fixed pole plate fixed relative to the housing, and a second movable pole plate fixed relative to the rotating shaft; The surface of the second fixed electrode plate is equally divided into N regions, and each region is formed by a metal sheet to create a different third pattern; The second moving electrode plate is disposed opposite to the second fixed electrode plate, and the second moving electrode plate and the metal sheet form a second capacitor. The digital signal is determined based on the second capacitor. The sum of the capacitance values ​​of the first detection capacitor and the second detection capacitor, along with the digital signal, are used to determine the rotation angle of the rotating shaft.

4. The capacitive encoder according to claim 3, characterized in that, The third pattern corresponding to the region is: a pattern corresponding to concentric fourth fan rings with different outer radii, or a pattern corresponding to a combination of concentric fourth fan rings with different outer radii, or a blank pattern.

5. The capacitive encoder according to claim 1, characterized in that, Also includes: A fastener fixed to the housing, the fastener comprising: a first surface facing the first moving electrode plate and a second surface facing the third moving electrode plate; The second electrode plate is disposed on the first surface, and the third fixed electrode plate is disposed on the second surface; The fixing component further includes a grounding component, which is located between the second electrode plate and the third fixed electrode plate, and is used to isolate the electric field between the second electrode plate and the third fixed electrode plate.

6. The capacitive encoder according to claim 1, characterized in that, Also includes: A support member fixed relative to the rotating shaft; The support includes: a third surface facing the first electrode plate and a fourth surface facing the second electrode plate; The first moving electrode plate includes: a third electrode plate disposed on the third surface and a fourth electrode plate disposed on the fourth surface, wherein the third electrode plate and the fourth electrode plate are electrically connected.

7. The capacitive encoder according to claim 6, characterized in that, The rotating shaft includes: a retaining part; The support member includes: a through hole that matches the shape of the retaining part; The rotating shaft passes through the through hole of the support member, and the retaining part contacts the through hole. The retaining part and the through hole cooperate with each other to make the support member and the rotating shaft rotate synchronously.

8. The capacitive encoder according to any one of claims 1 to 7, characterized in that, Also includes: A bearing is 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.

9. An electronic device, characterized in that, include: The capacitive encoder as described in any one of claims 1 to 8.

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