Grating code disc facilitating installation and positioning of multiple reading heads

Abstract

The utility model relates to the technical field of angle encoders, in particular to a grating coded disc convenient for installing and positioning a plurality of reading heads, which is provided with a scale grating, and a plurality of absolute position positioning grooves are arranged on the peripheral edge of the scale grating along the circumferential edge of the grating coded disc. The number of the absolute position positioning grooves is consistent with the number of reading heads configured in the encoder, the central angle between the adjacent absolute position positioning grooves is matched with the theoretical installation interval central angle of the reading heads, and the width of the absolute position positioning grooves along the circumference of the grating coded disc is controlled within 50 micrometers. According to the utility model, when multiple reading heads are installed and aligned, the absolute position positioning grooves are matched with the absolute position positioning scribed lines of the indicating gratings on the reading heads, so that the angular deviation between the actual installation position and the theoretical installation position of the reading heads is reduced, and the overall precision of the encoder is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of angle encoders, and specifically provides a grating code disk that is convenient for installing and positioning multiple reading heads. Background Art

[0002] Photoelectric encoder is a sensor that converts the mechanical geometric displacement on the output shaft into pulses or digital quantities through photoelectric conversion. It is a precision digital angle measuring device that integrates light, mechanics and electricity. It is usually composed of a shaft system, a light-emitting tube, a code disk, a slit, a receiving tube and a processing circuit. There are several concentric code tracks on the circular code disk of the angle encoder. Each code track is composed of light-transmitting and opaque sector areas. The sector area is the scale grating. A reading head is provided at the corresponding position of the scale grating. The reading head includes a light-emitting element provided on one side of the code disk and a photosensitive element provided at the corresponding position on the other side.

[0003] With the development of high-precision angle encoders, angle encoders gradually adopt a multi-reader structure design. Compared with single-reader encoders, multiple readhead encoders can improve measurement accuracy by multi-point measurement and data fusion. By comparing and correcting the measurement results of multiple readheads, errors can be reduced and more accurate position or angle measurements can be provided; and multiple readhead encoders provide redundant measurement signals. If one of the readheads fails or has an error, the other readheads can provide backup measurements, thereby increasing the reliability and fault tolerance of the system. However, during the assembly process of the encoder, multiple readheads require the grating code disk to be aligned with the readhead, and there are strict requirements for the installation position of the readhead and the angle between adjacent readheads. At present, during the installation of the readhead, the actual position and theoretical position of each readhead are mainly combined by mechanical positioning and human eye recognition, which generally forms an installation error of 0.5 to 2 degrees. The smaller the code disk size, the larger the installation error angle, which has an important impact on the overall accuracy of the high-precision angle encoder. Utility Model Content

[0004] In order to solve the above-mentioned problem, the utility model provides a grating code disk which is convenient for installation and positioning of multiple reading heads. A plurality of absolute position positioning grooves are arranged on the basis of the existing grating code disk. By aligning the absolute position positioning grooves with the absolute position positioning scale lines of the indicating grating, the angular position of the indicating grating on the reading head in the circumferential direction of the encoder is ensured, thereby reducing the angular deviation generated when the reading head is installed.

[0005] The utility model provides a grating code disk that is convenient for installation and positioning of multiple reading heads. A scale grating is arranged on the grating code disk. On the outer side of the scale grating, a plurality of absolute position positioning grooves are engraved along the circumferential direction of the grating code disk. The number of the absolute position positioning grooves is equal to the number of reading heads arranged in the encoder. The central angle between adjacent absolute position positioning grooves is equal to the central angle between theoretical installation positions of the reading heads. The absolute position positioning grooves are used to align with the absolute position positioning scale lines of the indicating gratings on the multiple reading heads. The width of the absolute position positioning grooves along the circumferential direction of the grating code disk is less than 50 microns.

[0006] Preferably, a marking position is provided in the middle of the absolute position positioning groove, and the width of the marking position along the circumferential direction of the grating code disk is less than half of the width of the absolute position positioning groove along the circumferential direction of the grating code disk.

[0007] Preferably, the width of the absolute position positioning groove along the circumferential direction of the grating code disk is 50 microns, and the width of the marking position along the circumferential direction of the grating code disk is 2 to 20 microns.

[0008] Compared with the prior art, the utility model can achieve the following beneficial effects:

[0009] The utility model provides an absolute position positioning groove with an absolute position identification function on a grating code disk. The absolute position positioning groove is used to align with the absolute position positioning scale line of the indicating grating on the multiple reading heads during the installation process of multiple reading heads. The optical pattern of the absolute position positioning scale line on the reading head is observed by illuminating with a light source. By adjusting the reading head to align the absolute position positioning scale line with the absolute position positioning groove, the actual installation position of the reading head can be ensured to be as close to the theoretical installation position as possible. However, the existing grating code disk lacks absolute position marks, and the installation position of the multiple reading heads can only be roughly determined by the human eye and the screw positions on the encoder, which will result in an angular deviation of 0.5 to 2 degrees between the actual installation position of each reading head and the theoretical installation position.

[0010] The utility model can be applied to various angle encoders, and the grating code disk with absolute position positioning grooves can facilitate the position determination of multiple reading heads, improve the overall installation accuracy of the encoder, and effectively improve the market competitiveness of the grating code disk. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a partial enlarged view of a grating code disk that is convenient for installation and positioning of multiple reading heads provided according to an embodiment of the utility model;

[0012] Figure 2 It is a schematic diagram of an indicating grating on a reading head provided according to an embodiment of the utility model.

[0013] Reference numerals include:

[0014] Scale grating 1, absolute position positioning groove 2, mark position 201, indicator grating 3, absolute position positioning scale line 301. DETAILED DESCRIPTION

[0015] Hereinafter, embodiments of the present utility model will be described with reference to the accompanying drawings. In the following description, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0016] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and do not constitute a limitation of the utility model.

[0017] like Figure 1 As shown, the grating code disk that is convenient for multiple reading heads to install and position is shown in the embodiment of the utility model, and is suitable for a dual reading head angle encoder. The grating code disk includes a scale grating 1 and an absolute position positioning groove 2. The scale grating 1 is a black and white annular code track engraved on the grating code disk. On the outside of the scale grating 1, two absolute position positioning grooves 2 are engraved along the circumferential direction of the grating code disk. The two absolute position positioning grooves 2 are arranged on the same straight line passing through the geometric center of the grating code disk, and the circumferential angle of the two absolute position positioning grooves 2 is 180 degrees. The width of the absolute position positioning groove 2 along the circumferential direction of the grating code disk is set to 50 microns.

[0018] During the installation of the encoder reading head, the existing process mainly adjusts the position of the printed circuit board of the reading head and the indicator grating 3 to be installed on the printed circuit board by mechanical positioning combined with human eye recognition. The assembly worker roughly determines the position where the two printed circuit boards should be installed according to the screw holes on the encoder printed circuit board, screws the printed circuit board on the main structure of the encoder, and then presses the indicator grating 3 on the printed circuit board according to the middle position of the two printed circuit boards observed by the human eye, and adjusts the position of the indicator grating 3 on the printed circuit board so that the two indicator gratings 3 are approximately 180° apart. Then, the indicator grating 3 can be glued to the printed circuit board to complete the installation of the reading head. The existing process mainly relies on human eye observation to determine the center angle between different reading heads. During the installation process, it is inevitable that there will be an angle deviation between the actual installation position and the theoretical installation position of the reading head, which affects the overall accuracy of the high-precision encoder.

[0019] like Figure 2As shown, the grating code disk provided by the embodiment of the utility model for facilitating the installation and positioning of multiple reading heads can effectively avoid the angle deviation generated in the existing process. After the printed circuit board is installed, the absolute position positioning groove 2 on the grating code disk is vertically illuminated by the LED light source, and a strip cursor is formed on the indicator grating 3 on the reading head. The position of the indicator grating 3 is adjusted so that the strip cursor is aligned with the absolute position positioning scale line 301 on the indicator grating 3 to determine the angular position of the indicator grating 3 in the circumferential direction of the encoder. The assembly integration of the reading head is optimized from the original mechanical positioning (millimeter error) to the optical pattern alignment (nanometer error), and its installation error can be ≤0.01 degrees, which greatly reduces the installation position error of the reading head and improves the position precision and accuracy of the reading head.

[0020] As a preferred embodiment, a mark position 201 is further provided in the middle position of the absolute position positioning groove 2, and the width of the mark position 201 along the circumferential direction of the grating code disk is 10 microns. The width of the absolute position positioning groove 2 can be set according to the installation accuracy of the reading head. In order to ensure that the angle deviation between the actual installation position of the reading head and the theoretical installation position is less than 0.01 degrees, the width of the absolute position positioning groove 2 along the circumferential direction of the grating code disk should be 50 microns, and the width of the mark position 201 along the circumferential direction of the grating code disk needs to be less than half of the width of the absolute position positioning groove 2 along the circumferential direction of the grating code disk, preferably set to 2 to 20 microns.

[0021] When a mark position 201 is provided in the absolute position positioning groove 2, the absolute position positioning groove 2 is illuminated by an LED light source, and two parallel strip cursors are formed on the indicating grating 3 on the reading head. By adjusting the position of the indicating grating 3, the absolute position positioning scale line 301 of the indicating grating 3 is sandwiched between the two strip cursors, and the angular position of the indicating grating 3 in the circumferential direction of the encoder can be determined, thereby further reducing the angular deviation between the actual installation position and the theoretical installation position of the reading head.

[0022] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0023] The above specific implementation methods of the utility model do not constitute a limitation on the protection scope of the utility model. Any other corresponding changes and modifications made according to the technical concept of the utility model should be included in the protection scope of the claims of the utility model.

Claims

1. A grating code disk that is convenient for installation and positioning of multiple reading heads, on which a scale grating is provided, characterized in that: On the outside of the scale grating, a plurality of absolute position positioning grooves are engraved along the circumferential direction of the grating code disk, the number of the absolute position positioning grooves is equal to the number of reading heads arranged in the encoder; the central angle between adjacent absolute position positioning grooves is equal to the central angle between the theoretical installation positions of the reading heads, and the absolute position positioning grooves are used to align with the absolute position positioning scale lines indicating the grating on the multiple reading heads; the width of the absolute position positioning grooves along the circumferential direction of the grating code disk is less than 50 microns.

2. The grating code disc for facilitating installation and positioning of multiple reading heads as claimed in claim 1, characterized in that: A marking position is provided in the middle of the absolute position positioning groove, and the width of the marking position along the circumferential direction of the grating code disk is less than half of the width of the absolute position positioning groove along the circumferential direction of the grating code disk.

3. The grating code disk for facilitating installation and positioning of multiple reading heads as claimed in claim 2, characterized in that: The width of the absolute position positioning groove along the circumferential direction of the grating code disk is 50 microns, and the width of the marking position along the circumferential direction of the grating code disk is 2 to 20 microns.

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