CN210014791U

CN210014791U - Encoder

Info

Publication number: CN210014791U
Application number: CN201921192881.6U
Authority: CN
Inventors: 鄢鹏飞
Original assignee: ZHEJIANG HECHUAN TECHNOLOGY CO LTD
Current assignee: ZHEJIANG HECHUAN TECHNOLOGY CO LTD
Priority date: 2019-07-26
Filing date: 2019-07-26
Publication date: 2020-02-04
Anticipated expiration: 2029-07-26

Abstract

The utility model discloses an encoder, which comprises an optical coding component, a magnetic coding component and a circuit board for outputting coding signals of the optical coding component and the magnetic coding component; the magnetic coding assembly comprises circular magnetic steel arranged at the center of the end of the rotating spindle, a first magnetic induction chip arranged on the circuit board and opposite to the edge of the circular magnetic steel, and a second magnetic induction chip arranged on the circuit board and opposite to the center of the circular magnetic steel. Adopt the magnetic field limit of first magnetism sense chip response magnet steel border position in the encoder in this application, still adopt the magnetic field change that second magnetism sense chip response magnet steel central point put simultaneously, combine the signal that two kinds of response chips sensed, can solve out absolute position information more accurately to improve the measurement accuracy of encoder, satisfy hybrid encoder's high accuracy high stability demand.

Description

Encoder

Technical Field

The utility model relates to an encoder technical field especially relates to an encoder.

Background

The photoelectric encoder is a sensor which is mainly used for measuring displacement or angle and is composed of a photoelectric code disk with a central shaft, an annular light and dark line on the code disk, and a photoelectric emitting and receiving device for reading and obtaining signals. Since the accuracy of the photoelectric encoder is calculated by scribing lines on the code wheel, the higher the accuracy is, the larger the code wheel is, the larger the volume of the encoder is, and the accuracy is not continuous.

The magneto-electric encoder adopts a magneto-electric design, generates and provides an absolute position of a rotor through a magnetic induction device and the change of a magnetic field, utilizes the magnetic device to replace a traditional code wheel, makes up for the defects of the magneto-electric encoder, and has better shock resistance, corrosion resistance, pollution resistance, reliable performance and high performance and simpler structure.

In order to meet the requirements of high precision and pollution resistance in encoder use, an optomagnetic hybrid encoder exists at present. However, the position information obtained by the current magneto-optical hybrid encoder cannot meet the precision requirement.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing an encoder has improved the precision that optomagnetic mixed encoder measured position information.

In order to solve the above technical problem, the utility model provides an encoder, which comprises an optical coding component, a magnetic coding component and a circuit board for outputting the coding signals of the optical coding component and the magnetic coding component;

the optical coding assembly comprises a code disc arranged at the end part of the rotating spindle, a photosensitive element arranged on the circuit board and opposite to a code channel of the code disc, and a light source which is opposite to the code channel and can emit light into the photosensitive element through the code channel;

the magnetic coding assembly comprises circular magnetic steel arranged at the center of the end part of the rotating spindle, a first magnetic induction chip arranged on the circuit board and just opposite to the edge of the circular magnetic steel, and a second magnetic induction chip arranged on the circuit board and just opposite to the center of the circular magnetic steel.

The magnetic steel comprises a semicircular N magnetic pole and a semicircular S magnetic pole;

the first magnetic induction chips comprise two orthogonal chips, each of the two first magnetic induction chips outputs a square wave signal with one period, and the phase difference between the two square wave signals is 90 degrees;

the second magnetic induction chip is used for outputting two periods of sine signals and two periods of cosine signals when the magnetic steel rotates for one circle.

The first magnetic induction chip is any one of a TMR chip, a GMR chip, an AMR chip or a Hall chip, and the second magnetic induction chip is an AMR chip.

The light source and the photosensitive element are arranged on the circuit board together, and light emitted by the light source can be reflected to the photosensitive element through the lighttight grating lines on the code channel.

The code channel comprises a plurality of grating lines formed by annularly arranged reflective metal sheets.

The circuit board is a PCB circuit board.

The code channel is any one of a cursor code channel, a Gray code channel, an M sequence code channel and a single-circle code channel.

The utility model provides an encoder, which comprises a light coding component, a magnetic coding component and a circuit board for outputting the coding signals of the light coding component and the magnetic coding component; the optical coding assembly comprises a coded disc arranged at the end part of the rotating main shaft, a photosensitive element arranged on the circuit board and opposite to a code channel of the coded disc, and a light source which is opposite to the code channel and through which light can enter the photosensitive element; the magnetic coding assembly comprises circular magnetic steel arranged at the center of the end part of the rotating spindle, a first magnetic induction chip arranged on the circuit board and opposite to the edge of the circular magnetic steel, and a second magnetic induction chip arranged on the circuit board and opposite to the center of the circular magnetic steel.

Adopt the magnetic field limit of first magnetism sense chip response magnet steel border position in the encoder in this application, still adopt the magnetic field change that second magnetism sense chip response magnet steel central point put simultaneously, combine the signal that two kinds of response chips sensed, can solve out more accurate positional information to improve the measurement accuracy of encoder, satisfy hybrid encoder's high accuracy high stability demand.

Drawings

In order to clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic cross-sectional structural diagram of an encoder according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a magnetic coding assembly according to an embodiment of the present invention;

fig. 3 is a coordinate diagram illustrating a correspondence relationship between output signals of the first magnetic sensor chip and the second magnetic sensor chip.

Detailed Description

In order to make the technical field better understand the solution of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings and the detailed description. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

As shown in fig. 1, fig. 1 is a schematic cross-sectional structure diagram of an encoder provided by an embodiment of the present invention, and the encoder may specifically include:

the circuit board 1 is used for outputting coded signals of the optical coding component and the magnetic coding component;

the optical coding assembly comprises a coded disc 3 arranged at the end part of a rotating main shaft 2, a photosensitive element 4 arranged on a circuit board 1 and opposite to a code channel of the coded disc 3, and a light source 5 which is opposite to the code channel and can emit light into the photosensitive element 4 through the code channel;

the magnetic coding component comprises a circular magnetic steel 6 arranged at the center of the end part of the rotating main shaft 2, a first magnetic induction chip 7 arranged on the circuit board 1 and opposite to the edge of the circular magnetic steel 6, and a second magnetic induction chip 8 arranged on the circuit board 1 and opposite to the center of the circular magnetic steel 6.

For convenience of description, in the following embodiments, the upper, lower, left, and right directions shown in the drawings are used as references for description, but this does not represent the arrangement direction of the encoder in practical application, and in practical application, as long as the relative positions of the components of the encoder are the same as the relative positions exemplified in the drawings referred to in this application, repeated description is omitted in the following embodiments.

As shown in FIG. 1, the optical encoder assembly of the present embodiment, which can refer to the component structure of a conventional photoelectric encoder, mainly includes a code wheel 3 with a grating code track, a light source 5, and a photosensitive element 4 for sensing light and converting light signals into electrical signals. The optical encoder assembly in this embodiment is similar to a conventional optical encoder in structure and operates in the same principle, and will not be discussed in detail here.

However, there are various types of optical encoders depending on the code channel. In consideration of the fact that in practical application, an optical encoder is often polluted by dust and oil stains on a code track or generates jump due to vibration, so that a measurement result is not accurate. In order to compensate for the defect, the magnetic encoder assembly with better stability is adopted for position measurement in the application, but the magnetic encoder also has the problem of low measurement accuracy. For example, for an optical encoder, the scale values corresponding to the code track positions read by the current reading head can be measured (i.e. the scale line representing the position of the scale line located on the code disc 3), and the phase angle at the scale line position (representing the specific position point on the scale line) can be further measured; however, in the case of a magnetic encoder, it is possible to measure only a scale value and not obtain a phase angle, or the error of the obtained phase angle is very large.

Therefore, when the data collected by the optical coding assembly and the magnetic coding assembly are calculated, the absolute position is obtained by combining the phase angle calculated by the optical coding assembly and the reticle value calculated by the electric coding assembly. Of course, the magnetic encoding assembly can also calculate the number of rotation turns of the rotating spindle 2 of the encoder, and the information of the multi-turn absolute position can be obtained by combining the absolute position.

Based on the above description, it is understood that, in the present embodiment, regardless of the code track used on the code wheel 3, the phase angle of the current ruled line may be calculated. Specifically, any one of a cursor code channel, a gray code channel, an M-sequence code channel, and a single-turn code channel may be adopted, which is not specifically limited in this embodiment.

However, it should be noted that, when actually calculating the absolute position, in order to obtain a more accurate absolute position, it is often considered that the absolute positions calculated by the optical encoding component and the electrical encoding component are mutually corrected to reduce the measurement error and obtain a more accurate measurement result. Therefore, it is required that the optical signal data collected by the optical encoding module can also be used to calculate the scribing value, and the number of code channels on the code wheel 3 is required to be not less than two turns. In the encoder which does not require the optical coding component and the electrical coding component, the code disc 3 adopting the single-circle code channel can also realize the technical scheme of the application. Therefore, the type of the code channel can be selected according to actual needs.

For the magnetic coding component, in order to reduce the space volume of the encoder as much as possible, the circular magnetic steel 6 can be arranged at the central position of the coded disc 3, so that the coded disc 3 and the circular magnetic steel 6 can rotate together with the rotating main shaft 2 in the same plane, the structure arrangement of the coded disc 3 and the circular magnetic steel 6 is more compact and reasonable, and the overall structure of the encoder is reduced.

As shown in fig. 1, two kinds of chips arranged at different positions are adopted, magnetic fields at different positions of the circular magnetic steel 6 are measured, the first magnetic induction chip 7 is just opposite to the edge position of the circular magnetic steel 6, the second magnetic induction chip 8 is just opposite to the center position of the circular magnetic steel 6, the magnetic fields detected by the first magnetic induction chip 7 and the second magnetic induction chip 8 are different from each other along with the rotation of the circular magnetic steel 6 to different positions, and the magnetic fields detected by the first magnetic induction chip 7 and the second magnetic induction chip 8 are combined, so that accurate absolute positions can be obtained, and the number of rotation turns can be obtained.

The absolute position obtained for the optical encoder assembly includes primarily the reticle value and the reticle phase angle, while the absolute position obtained for the magnetic encoder assembly includes primarily the reticle value. Because the photoelectric coding assembly is unstable and is easy to be polluted by oil, when the absolute position is actually determined, the scribing value obtained by the magnetic coding assembly and the scribing phase angle obtained by the optical encoder assembly can be combined, so that a more accurate absolute position is obtained, and then the number of rotation turns is combined, so that the multi-turn absolute position can be obtained.

To sum up, provide an encoder that optomagnetic mixes in this application, wherein adopt first magnetic induction chip 7 and second magnetic induction chip 8 to detect at different positions simultaneously and obtain magnetic field signal for the absolute position and the number of revolutions that the magnetic encoding subassembly obtained are more accurate, further improve the measurement accuracy of encoder.

Optionally, in another specific embodiment of the present invention, the method may further include:

the circular magnetic steel 6 comprises a semicircular N magnetic pole and a semicircular S magnetic pole;

the first magnetic induction chips 7 comprise two orthogonal chips, and the measuring directions of the two first magnetic induction chips 7 are both along the tangential direction of the circular magnetic steel 6; every time the circular magnetic steel 6 rotates for one circle, the two first magnetic induction chips 7 respectively output a periodic square wave signal, and the phase difference of the two square wave signals is 90 degrees;

the second magnetic induction chip 8 is used for outputting two periods of sine signals and two periods of cosine signals when the circular magnetic steel 6 rotates for one circle.

Specifically, referring to fig. 2, fig. 2 is a schematic structural diagram of a magnetic coding assembly according to an embodiment of the present invention, and fig. 2 shows relative positions between the circular magnetic steel 6 and the first magnetic sensing chip 7 and the second magnetic sensing chip 8. The measuring directions of the two first magnetic induction chips 7 are parallel to the tangential direction of the circular magnetic steel 6, and the difference between the measuring directions is 90 degrees. For the magnetic field detected by the magnetic field chip, a periodic change is generated along with the rotation of the circular magnetic steel 6.

As shown in fig. 3, fig. 3 is a coordinate diagram illustrating a corresponding relationship between output signals of the first magnetic sensing chip and the second magnetic sensing chip. In fig. 3, each time the circular magnetic steel 6 rotates one circle, the first magnetic induction chips 7 can output a square wave signal of one period, and the difference between the square wave signals of the two first magnetic induction chips 7 is 90 degrees; correspondingly, every time the circular magnetic steel 6 rotates one circle, the second magnetic induction chip 8 can output sine signals and cosine signals of several periods.

As can be seen from fig. 3, if the circular magnetic steel 6 is divided into four sector areas of 90 degrees, the current absolute positions in the different sector areas are that the high and low levels output by the two first magnetic induction chips 7 have different combinations; accordingly, according to the different combinations of the high and low levels output by the two first magnetic induction chips 7, the sine and cosine signals of the present position corresponding to the several periods output by the second magnetic induction chip 8 can be determined.

For example, as shown in fig. 3, when the output of the first magnetic induction chip Hall1 is high, the output of the second first magnetic induction chip Hall2 is low; it can be determined that the current output of the second magnetic induction chip 8 is a sine and cosine signal in the first period, and the current absolute position information can be further obtained when the sine signal output by the second magnetic induction chip 8 is a and the previous signal is b.

It should be noted that, for each rotation of the circular magnetic steel 6, the second magnetic induction chip 8 outputs sine and cosine signals of two periods, so as to calculate a more accurate absolute position based on the sine and cosine signals. Although the second magnetic induction chip 8 can only output sine and cosine signals of one period when the circular magnetic steel 6 rotates for one circle, the absolute position can be calculated without adopting the first magnetic induction chip 7 to detect the change of the magnetic field, but the accuracy of the absolute position calculated by the calculation method is lower. Therefore, the embodiment of combining two first magnetic induction chips 7 and one second magnetic induction chip 8 is a preferred embodiment.

In addition, for the first magnetic induction chip 7 capable of outputting square wave signals and the second magnetic induction chip 8 capable of outputting sine and cosine signals of two periods, the type of the output signals is determined by the internal circuit structure, and the improvement of a software program is not involved. And the first magnetic induction chip 7 and the second magnetic induction chip 8 having such functions are already existing in the prior art at present, so the present embodiment is in line with the protection object of the utility model.

The first magnetic sensing chip 7 may be any one of a TMR chip, a GMR chip, an AMR chip, or a hall chip, or other chips having similar functions, and the second magnetic sensing chip 8 may be an AMR chip.

the photosensitive element 4 and the light source 5 are arranged on the circuit board 1 together, and light emitted by the light source 5 can be reflected to the photosensitive element 4 through the code channel.

Specifically, in order to simplify the internal structure of the encoder and facilitate the power supply of the light source 5 by the circuit board 1, the light sensor 4 and the light source 5 may be integrated into a whole and jointly disposed on the circuit board 1. And the grating code channel at the moment is also formed by alternately arranging the light-reflecting scribed lines and the non-light-reflecting scribed lines correspondingly.

For example, a plurality of metal sheets can be uniformly arranged in a ring shape to form the photoelectric code channel. When the light from the light source 5 is irradiated onto the metal sheet, the light is reflected, and the reflected light is received by the photosensitive element 4. Of course, the present application does not exclude the use of gratings made of reflective elements made of other materials, and the present application is not limited thereto.

In addition, as for the reflective metal sheet, a metal film layer may be plated on the code wheel 3, or the metal code wheel 3 may be directly adopted, and a grating hole or the like is formed on the code wheel 3 to form a grating capable of reflecting light, which is not specifically limited in this application.

For the circuit board 1 in each of the above embodiments, a PCB circuit board or other types of circuit boards 1 may be specifically adopted, which is not specifically limited in this application.

The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

Claims

1. An encoder is characterized by comprising an optical encoding component, a magnetic encoding component and a circuit board for outputting encoding signals of the optical encoding component and the magnetic encoding component;

2. The encoder of claim 1, wherein the magnetic steel comprises a semicircular N pole and a semicircular S pole;

the first magnetic induction chips comprise two orthogonal chips, and the measuring directions of the two first magnetic induction chips are both along the tangential direction of the circular magnetic steel; every time the magnetic steel rotates for one circle, the two first magnetic induction chips respectively output a periodic square wave signal, and the phase difference between the two square wave signals is 90 degrees;

3. The encoder according to claim 2, wherein the first magnetic sensing chip is any one of a TMR chip, a GMR chip, an AMR chip, or a hall chip, and the second magnetic sensing chip is an AMR chip.

4. The encoder of claim 1, wherein the photosensitive element and the light source are disposed on a circuit board, and wherein light from the light source is reflected onto the photosensitive element through the grating lines that are opaque to the code track.

5. The encoder of claim 4, wherein the track comprises a plurality of grating lines formed of annularly disposed reflective metal sheets.

6. The encoder of claim 1, wherein the circuit board is a PCB circuit board.

7. The encoder as claimed in any one of claims 1 to 6, wherein the code track on the code disc is any one of a cursor code track, a Gray code track, an M-sequence code track, and a single-turn code track.