Capacitive encoder

Abstract

The invention provides a capacitive encoder which is used for being arranged on a rotating shaft of an object to be detected, the capacitive encoder comprises a stator assembly and a rotor part, the stator assembly comprises a transmitter and a receiver, the transmitter can transmit electric signals, and the receiver can receive the electric signals transmitted by the transmitter; comprising a connecting part and a rotor part, the connecting part and the rotor part are integrally formed, the rotor part is connected with a rotating shaft of an object to be detected so that the rotor part can synchronously rotate with the rotating shaft, a metal wire is arranged on the rotor part, and the metal wire is a periodically changing curve. An electric signal emitted by the emitter can pass through the metal wire and is received by the receiver. According to the capacitive encoder provided by the invention, the connecting part and the rotor part adopt the integrally formed structure, and the periodically changing metal wires are directly formed on the rotor part, so that the manufacturing tolerance is reduced while the function of the capacitive encoder is realized.

Description

Technical Field

[0001] The present application relates to the technical field of encoders, and in particular to a capacitive encoder. Background Art

[0002] Encoders are common in motion control products. Rotary encoders are key components in the feedback loop of motion control. Devices that convert mechanical motion into electrical signals, encoders can provide engineers with basic data such as position, speed, distance and direction to optimize the performance of the entire system.

[0003] Optical, magnetic and capacitive are the three main encoder technologies available to engineers. Capacitive sensors offer greater accuracy and reliability.

[0004] Capacitive encoders detect changes in capacitive reactance on the receiving board and convert them into increments of rotary motion using a demodulation algorithm. Capacitive can withstand a variety of environmental contaminants and can better withstand vibration and extreme temperatures. Capacitive encoders have longer life, smaller size and lower power consumption than optical encoders. It is not affected by magnetic interference and electrical noise and is as reliable as a magnetic encoder, but with higher accuracy and resolution. Summary of the invention

[0005] In view of this, the present application provides a capacitive encoder, which realizes the function of a capacitive encoder while reducing manufacturing tolerances by adopting an integrally formed structure for the connecting part and the rotor part and directly forming periodically changing metal traces on the rotor part.

[0006] In a first aspect, an embodiment of the present application provides a capacitive encoder, the capacitive encoder is used to be set to a rotating shaft of an object to be detected, and the capacitive encoder includes:

[0007] A stator assembly, the stator assembly comprising a transmitter and a receiver, the transmitter being capable of transmitting an electrical signal, and the receiver being capable of receiving the electrical signal transmitted by the transmitter;

[0008] The rotor component includes a connecting portion and a rotor portion, wherein the connecting portion and the rotor portion are integrally formed, and the rotor component is connected to the rotating shaft of the object to be detected so that the rotor component can rotate synchronously with the rotating shaft. The rotor component is provided with a metal trace, and the metal trace is a curve that changes periodically. The electrical signal emitted by the transmitter can pass through the metal trace and be received by the receiver.

[0009] In a first possible implementation, in combination with the first aspect above, the rotor component further includes a connecting hole, one side of the rotor part is connected to the connecting part, the connecting hole passes through the connecting part and the rotor part in sequence, and the rotor component is plugged into the rotating shaft through the connecting hole.

[0010] In a second possible implementation, in combination with the above-mentioned first possible implementation, the projection of the rotor part on the horizontal plane is a hollow circle, the rotor part includes a first surface and a second surface, the radial dimension of the rotor part gradually decreases from the first surface to the second surface, and the metal routing is formed on the first surface of the rotor part.

[0011] In a third possible implementation manner, in combination with the second possible implementation manner, the metal routing is formed on the first surface by at least one of a laser forming technology and a direct pad printing process.

[0012] In a fourth possible implementation, in combination with the first possible implementation, the radial dimension of the rotor portion is larger than that of the connecting portion, and the central axis of the rotor portion coincides with the central axis of the connecting portion.

[0013] In a fifth possible implementation, in combination with the first aspect, the capacitive encoder further includes a main body having an installation space therein, and the stator assembly and the rotor component are both arranged in the installation space.

[0014] In a sixth possible implementation, in combination with the first aspect or any one of the first to fifth possible implementations, the transmitter is arranged on one side of the main body, the receiver is arranged on the other side of the main body and corresponds to the position of the transmitter, and the rotor member is arranged between the transmitter and the receiver.

[0015] In a seventh possible implementation, in combination with the first aspect or any one of the first to fifth possible implementations, the stator assembly further includes: a substrate, and the transmitter and the receiver are both arranged on the substrate.

[0016] In an eighth possible implementation manner, in combination with the first aspect or any one of the first to fifth possible implementation manners, the rotor component is an integrally formed rotor component using an injection molding process.

[0017] The above technical solution adopts an integrally formed connection part and rotor part, avoiding the processing flow of dividing the connection part and the rotor part into two structural parts and then connecting them, and the integral forming reduces the manufacturing tolerance. Accordingly, the manufacturing accuracy is improved. The periodically changing metal routing is formed on the rotor part through a predetermined process, so that the capacitive encoder can not only ensure a high manufacturing accuracy, but also realize the stable detection of the basic data of the object to be detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of a three-dimensional structure of a capacitive encoder provided in an embodiment of the present application;

[0019] Figure 2 is a schematic diagram of a three-dimensional structure of a capacitive encoder provided in an embodiment of the present application from another angle;

[0020] Figure 3 is a simplified structural diagram of an implementation method of a capacitive encoder provided in an embodiment of the present application;

[0021] Figure 4 It is a simplified structural diagram of another implementation mode of a capacitive encoder provided in an embodiment of the present application.

[0022] List of reference numerals:

[0023] 100: Capacitive encoder; 10: Stator assembly; 101: Transmitter;

[0024] 102: receiver; 103: substrate; 20: rotor member;

[0025] 201: connecting portion; 202: rotor portion; 2021: first surface;

[0026] 2022: second surface 203: connection hole 1: metal wiring;

[0027] 30: main body; 301: installation space; 200: object to be detected;

[0028] 40: Rotation axis. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0030] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0031] The following is attached to the instruction manual Figure 1-Figure 4 , a capacitive encoder 100 according to an embodiment of the present invention is described.

[0032] like Figure 3 and Figure 4 As shown, the capacitive encoder 100 is used to be arranged on a rotating shaft 40 of the object to be detected 200, thereby realizing basic data (such as position, speed, distance and direction, etc.) of the object to be detected 200.

[0033] For example, the object 200 to be detected may be a motor, and the capacitive encoder 100 may be used to detect the rotation angle of the motor.

[0034] According to one or more embodiments of the present invention, the capacitive encoder 100 includes a stator assembly 10 and a rotor assembly 20. The stator assembly 10 includes a transmitter 101 and a receiver 102. The transmitter 101 can transmit an electrical signal, and the receiver 102 can receive the electrical signal transmitted by the transmitter 101.

[0035] like Figure 1 and Figure 2 As shown, the rotor part 20 includes a connecting part 201 and a rotor part 202. The connecting part 201 and the rotor part 202 are a single component formed in one piece. And the rotor part 20 is connected to the rotating shaft 40 of the object to be detected 200 so that the rotor part 20 can rotate synchronously with the rotating shaft 40. Compared with the method in which the rotor and the connecting part are manufactured separately and then connected together by technical means, the rotor part 20 of the capacitive encoder 100 of the present invention has the beneficial effect of reducing manufacturing tolerance and improving precision. This is because the rotor part and the connecting part are manufactured separately and then combined by subsequent means, which will cause the two structural parts of the rotor part and the connecting part to have certain manufacturing tolerances during manufacturing. And when the rotor part and the connecting part are connected later, the rotor part is usually fixed to the connecting part by dispensing glue, so as to realize the connection between the rotor and the object to be detected. When the temperature becomes high, the adhesion of the glue used for bonding will decrease, and the glue will age after long-term operation. At the same time, the amount of glue dispensed is difficult to control, and too much or too little glue locally will cause the rotor to rotate unbalanced.

[0036] In the capacitive encoder 100 of the embodiment of the present invention, the rotor component 20 is provided with a metal trace 1 , which is a curve showing periodic changes. The electrical signal emitted by the transmitter 101 can pass through the metal trace 1 and be received by the receiver 102 .

[0037] In other words, if Figure 1 As shown. Combined with what has been said above, the rotor part 20 of the capacitive encoder 100 of the embodiment of the present invention is an integrally formed structure of a connecting part 201 and a rotor part 202. In other words, the rotor part 20 itself is not only a connecting structure that can be connected to the rotating shaft 40 of the object to be detected 200, but can also be used as a measuring component for measuring the basic data (such as position, speed, distance and direction, etc.) of the object to be detected 200. Therefore, while ensuring the rotor function, the one-piece structure improves the manufacturing accuracy.

[0038] According to the capacitive encoder 100 of the embodiment of the present invention, by adopting the integrally formed connecting portion 201 and the rotor portion 202, the processing flow of dividing the connecting portion 201 and the rotor portion 202 into two structural parts and then combining them into one is avoided, and the integral forming reduces the manufacturing tolerance. Accordingly, the manufacturing accuracy is improved. The metal trace 1 that changes periodically can be formed on the rotor part 20 through a predetermined process, so that the capacitive encoder 100 can ensure a high manufacturing accuracy and realize stable detection of the basic data of the object 200 to be detected.

[0039] In some embodiments of the present invention, the metal routing may be set as a sinusoidal routing or any curve that changes periodically.

[0040] In some embodiments of the present invention, the rotor component 20 may be a plastic structural component, which has low cost and is easier to manufacture and shape.

[0041] In some embodiments of the present invention, the rotor component 20 further includes a connecting hole 203 , one side of the rotor portion 202 is connected to the connecting portion 201 , the connecting hole 203 passes through the connecting portion 201 and the rotor portion 202 in sequence, and the rotor component 20 is plugged into the rotating shaft 40 through the connecting hole 203 .

[0042] Specifically, Figure 1 and Figure 2 As shown, a metal trace 1 is provided on one side of the rotor part 202, and the other side of the rotor part 202 is connected to the connecting part 201. Since the rotor part 20 needs to be connected to the rotating shaft 40 of the object to be detected 200, a connecting hole 203 is provided. As shown in the figure, the connecting hole 203 is a through hole that passes through the connecting part 201 and the rotor part 202 in sequence. The connection stability between the rotor part 20 and the rotating shaft 40 of the object to be detected 200 is improved.

[0043] Furthermore, if Figure 1and Figure 2 As shown, the projection of the rotor part 202 on the horizontal plane is a hollow circle, and the horizontal plane can be a horizontal plane perpendicular to the vertical plane. As can be seen from the foregoing, the horizontal plane projection of the rotor part 202 is a hollow circle because a connecting hole 203 is provided at the center of the circle. The rotor part 202 includes a first surface 2021 and a second surface 2022, and the radial dimension of the rotor part 202 gradually decreases from the first surface 2021 to the second surface 2022. It can be understood that the size of the upper part of the rotor part 202 is larger than the size of the lower part. That is, the radial dimension of the first surface 2021 is larger than the radial dimension of the second surface 2022.

[0044] Furthermore, the projection of the rotor part 202 on the vertical plane may be a trapezoid, and the vertical plane may be Figure 1 and Figure 2 A plane extending in the up-down direction shown in .

[0045] The first surface 2021 of the rotor part 202 is formed with a metal trace 1 , and the metal trace 1 can allow the signal of the transmitter 101 of the stator assembly 10 to pass through and be received by the receiver 102 .

[0046] like Figure 1 and Figure 2 As shown, the radial dimension of the rotor part 202 is larger than that of the connecting part 201, and the central axis of the rotor part 202 coincides with the central axis of the connecting part 201. Specifically, the rotor part 202 and the connecting part 201 are an integrally formed structure that rotates coaxially, so that the rotation of the rotor part 20 can be balanced.

[0047] In some embodiments of the present invention, the rotor member 20 is a rotor member 20 integrally formed by an injection molding process. The injection molding process can be integrally formed by, for example, a melt solidification process. Therefore, the rotor member 20 can be made of a polymer material that can be melted at high temperature and then cooled and molded. Therefore, compared with printed circuit board (PCB) materials that cannot be melt solidified, the processing cost of the rotor member 20 in the embodiment of the present invention is relatively low.

[0048] In some embodiments of the present invention, laser-direct-structuring (LDS) or direct pad printing (PDS) may be used to form metal traces 1 on the first surface 2021. Metal traces 1 may be formed directly on the first surface 2021 by laser-direct-structuring or direct pad printing. Forming metal traces 1 directly on the first surface 2021 by laser-direct-structuring or direct pad printing is simple in operation, mature in process, and low in manufacturing cost.

[0049] Laser forming technology is a process that transfers the antenna design directly to the surface of the plastic part by operating a laser beam. Laser activation can be used to start the reaction, forming very fine particles on the surface of the laser-treated plastic part to form a rough surface. Copper or other metal traces 1 are deposited on the treated plastic surface, and good adhesion is established between the deposited metal layer and the thermoplastic material. Then, through metallization, a periodically changing curved pattern, such as a sinusoidal metal trace, is formed on the first surface 2021 of the rotor part 202. Laser forming technology has extremely high precision.

[0050] The direct pad printing process is to use pad printing technology to directly print conductive silver paste on the formed shell to form a metal antenna shape, without the need for electroplating. It is a low-cost, highly reliable, and environmentally friendly process. According to one or more embodiments of the present invention, a steel plate can be exposed using photosensitive glue, and a periodically changing curved pattern can be etched out by development. The periodically changing curved pattern can be printed on the first surface 2021 of the rotor part 202 using a pad printing machine using a rubber head, and then the final rotor part 202 is made by thermal curing. The advantage of this technology is that the circuit can be directly printed, no special laser modified materials are required, and the cost is low.

[0051] Other surface metallization wiring processes may also be used to form metal traces on the first surface 2021. The embodiment of the present invention is the first to use laser forming technology and direct pad printing technology to manufacture the metal traces 1 on the rotor member 20. Compared with other surface metallization wiring processes, laser forming technology and direct pad printing technology make it simple to directly form the metal traces 1 on the first surface 2021. These processes are also relatively mature, thereby reducing the manufacturing cost of the encoder. In some embodiments of the present invention, such as Figure 3 As shown, the transmitter 101 is arranged on one side of the main body 30, the receiver 102 is arranged on the other side of the main body 30 and corresponds to the position of the transmitter 101, and the rotor 20 is arranged between the transmitter 101 and the receiver 102. Thus, the signal transmitted by the transmitter 101 passes through the metal trace 1 and is then received by the receiver 102, so that the basic data of the object 200 to be detected can be detected.

[0052] In some embodiments of the present invention, Figure 4 As shown, the stator assembly 10 further includes a substrate 103, and the transmitter 101 and the receiver 102 are both arranged on the substrate 103. That is, the transmitter 101 and the receiver 102 are an integrated structure, and are both arranged on the substrate 103. The signal transmitted by the transmitter 101 passes through the metal wiring 1 and then returns to the receiver 102, thereby obtaining basic data of the object to be detected 200. The size of the overall structure is reduced, saving space.

[0053] The present invention is not limited to this. Figure 3 and Figure 4 As shown, the capacitive encoder 100 further includes a main body 30, and the main body 30 has an installation space 301, and the stator assembly 10 and the rotor component 20 are both arranged in the installation space 301. With the main body 30 as a shell, the internal installation space 301 can provide a stable protection foundation for the stator assembly 10 and the rotor component 20.

[0054] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the existence of other identical factors in the process, method, article or device including the elements.

[0055] Finally, it should be noted that the above are only preferred embodiments of the present invention, which are only used to illustrate the technical solution of the present invention, and are not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A capacitive encoder, the capacitive encoder (100) being used to be arranged on a rotating shaft (40) of an object (200) to be detected, characterized in that: The capacitive encoder (100) comprises: A stator assembly (10), the stator assembly (10) comprising a transmitter (101) and a receiver (102), the transmitter (101) being capable of transmitting an electrical signal, and the receiver (102) being capable of receiving the electrical signal transmitted by the transmitter (101); A rotor component (20) comprises a connecting portion (201) and a rotor portion (202), wherein the connecting portion (201) and the rotor portion (202) are integrally formed, and the rotor component (20) is connected to a rotating shaft (40) of the object to be detected (200) so that the rotor component (20) can rotate synchronously with the rotating shaft (40). The rotor component (20) is provided with a metal trace (1), wherein the metal trace (1) is a curve that changes periodically, and the electrical signal emitted by the transmitter (101) can pass through the metal trace (1) and be received by the receiver (102).

2. The capacitive encoder according to claim 1, characterized in that: The rotor component (20) further comprises a connecting hole (203), one side of the rotor part (202) is connected to the connecting part (201), the connecting hole (203) passes through the connecting part (201) and the rotor part (202) in sequence, and the rotor component (20) is plugged into the rotating shaft (40) through the connecting hole (203).

3. The capacitive encoder according to claim 2, characterized in that: The projection of the rotor part (202) on a horizontal plane is a hollow circle, the rotor part (202) comprises a first surface (2021) and a second surface (2022), the radial dimension of the rotor part (202) gradually decreases from the first surface (2021) to the second surface (2022), and the first surface (2021) of the rotor part (202) is provided with the metal trace (1).

4. The capacitive encoder according to claim 3, characterized in that: The metal trace (1) is formed on the first surface (2021) by at least one of a laser forming technology and a direct pad printing process.

5. The capacitive encoder according to claim 2, characterized in that: The radial dimension of the rotor part (202) is larger than that of the connecting part (201), and the central axis of the rotor part (202) coincides with the central axis of the connecting part (201).

6. The capacitive encoder according to claim 1, characterized in that: The capacitive encoder (100) further comprises a main body (30), wherein the main body (30) has an installation space (301), and the stator assembly (10) and the rotor component (20) are both arranged in the installation space (301).

7. The capacitive encoder according to any one of claims 1 to 6, characterized in that: The transmitter (101) is arranged on one side of the main body (30), the receiver (102) is arranged on the other side of the main body (30) and corresponds to the position of the transmitter (101), and the rotor (20) is arranged between the transmitter (101) and the receiver (102).

8. The capacitive encoder according to any one of claims 1 to 6, characterized in that: The stator assembly (10) further comprises: a substrate (103), and the transmitter (101) and the receiver (102) are both arranged on the substrate (103).

9. The capacitive encoder according to any one of claims 1 to 6, characterized in that: The rotor component (20) is a rotor component (20) that is integrally formed using an injection molding process.

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