A photoelectric speed sensor

Abstract

The present invention provides a photoelectric speed sensor, which belongs to the technical field of brake control systems. The shift fork of the photoelectric speed sensor is installed at the left end of the rotating shaft; the external main body of the housing is sleeved in the wheel axle of the external device, and the housing flange is installed at one end of the wheel axle of the external device; the first bearing is installed on the bearing seat; the second bearing is installed at the left end of the interior of the housing; the rotating shaft is installed in the interior of the housing, the right end of the rotating shaft is sleeved in the first bearing, and the left end of the rotating shaft is sleeved in the second bearing; the photoelectric seat is installed in the interior of the housing, and the photoelectric seat is electrically connected to the electrical connector; the bearing seat is installed at the right end of the interior of the housing; the encoder is sleeved on the rotating shaft, and the encoder is located on the left side of the interior of the photoelectric seat. It can effectively avoid speed measurement failure caused by photoelectric element failure; it has high resolution; it can realize the determination of the forward and reverse rotation of the wheel axle; the light reflection transceiver structure only requires the encoder and the photoelectric seat to be aligned, and the alignment requirement is low, which can reduce the machining accuracy requirements and the product assembly process requirements; and it has good dustproof characteristics.

Description

Technical Field

[0001] The present invention belongs to the technical field of brake control systems, and in particular relates to a photoelectric speed sensor. Background Art

[0002] Currently, all photoelectric speed sensors are transmissive photoelectric speed sensors, whose core components are transmissive encoder disks, light-emitting components and photosensitive components. After engineering applications and experimental tests, transmissive photoelectric speed sensors are greatly affected by dust. After a short period of use, they need to be cleaned, otherwise they cannot output wheel speed signals of a specific amplitude.

[0003] A locomotive vehicle photoelectric speed sensor in the related art has core components of a translucent encoder disk, a light-emitting assembly, and a photosensitive assembly. The light-emitting assembly includes a power conversion circuit and two light-emitting elements, and the photosensitive assembly includes a signal processing circuit and two photosensitive elements. This structure can output two sets of square wave signals proportional to the wheel speed, but there are three disadvantages in actual application: (1) The signal form is single and the signal redundancy is small. The power conversion circuit in the light-emitting assembly and the signal processing circuit in the photosensitive assembly are both single redundant. If any component in the circuit is damaged, the speed measurement will fail, and the reliability of the sensor is low; (2) The phases of the two sets of signals are random, and it is impossible to determine the forward and reverse rotation of the wheel. In this structure, the phase of the output signal depends on the installation position of the light-emitting element and the photosensitive element. Since the encoder disk has a high resolution, a slight position deviation will affect the phase difference of the two sets of signals. This structure determines that the phase difference of the two sets of signals of each translucent photoelectric speed sensor is different, which determines that it cannot determine the forward and reverse rotation of the wheel; (3) The radial installation position requirements of the light-emitting element and the photosensitive element of the sensor are too high. The light-emitting element and the photosensitive element must be aligned with each other strictly. Even the slightest assembly deviation will result in no sensor signal output, so this structure requires advanced processing and assembly techniques. Secondly, under large impacts, the photosensitive element cannot continuously receive light signals due to the irregular vibration of the transmitting and receiving elements, resulting in unstable speed measurement output. Another photoelectric speed sensor that measures the wheel speed during aircraft landing has a translucent encoder disk and a photoelectric switch as its core components. In actual engineering applications and laboratory testing, this structure has been found to be significantly affected by dust. After three to five months of engineering application, it needs to be cleaned; otherwise, it will not be able to output a wheel speed signal of a specific amplitude. The reason for this is analyzed as follows: the encoder disk is prone to dust accumulation. The encoder disk's grating is a translucent structure with 2mm x 0.3mm through-holes. The grating is small and prone to dust accumulation. Summary of the Invention

[0004] To address the problems of low reliability, unstable output phase, and poor dust resistance in conventional photoelectric speed sensors, the present invention proposes a redundant, high-resolution, reflective, dust-proof, and moisture-proof photoelectric speed sensor capable of outputting a high-resolution, redundant square wave signal proportional to the wheel speed during braking in aircraft, high-speed trains, locomotives, and the like. The technical solution is as follows:

[0005] A photoelectric speed sensor includes: a shift fork, a rotating shaft, a housing, an encoder, a photoelectric seat, a bearing seat, an electrical connector, a first bearing, and a second bearing.

[0006] The shift fork is installed at the left end of the rotating shaft and is connected to the shift rod of the wheel axle of the external device; the external main body of the shell is sleeved in the wheel axle of the external device, and the shell flange is installed at one end of the wheel axle of the external device to achieve axial and angular fixation of the shell and the external device; the first bearing is installed on the bearing seat; the second bearing is installed at the left end inside the shell; the rotating shaft is installed inside the shell, the right end of the rotating shaft is sleeved in the first bearing, and the left end of the rotating shaft is sleeved in the second bearing; the photoelectric seat is installed inside the shell, and the photoelectric seat is electrically connected to the electrical connector; the bearing seat is installed at the right end inside the shell; the encoder is sleeved on the rotating shaft, and the encoder is located on the left side inside the photoelectric seat.

[0007] The internal circuit of the photoelectric seat includes three parallel circuits, each circuit is provided with two groups of photoelectric elements, and the positions of the photoelectric elements in the three circuits correspond to the positions of the three circles of code tracks on the encoder: the two groups of photoelectric elements on the first circuit generate output signals Z, ... The two groups of photoelectric elements on the second circuit generate output signals B, The two groups of photoelectric elements in the third circuit generate output signals A,

[0008]

[0009] Among them, there are three code tracks on the circumference of the encoder marked with paint. The first code track has a marking line, which is consistent with the output signal Z, Correspondingly, the resolution is 1Hz / r; the second circle code channel has 180 groups of marking lines, forming 180 groups of light and dark alternating changes, with an angular direction of 2° as a cycle, and output signal B, Correspondingly, the resolution is 180Hz / r; the third circle code channel has 180 groups of marking lines, forming 180 groups of light and dark alternating changes, with an angular direction of 2° as a cycle, and the output signal A, Correspondingly, the resolution is 180Hz / r; the marking lines of the second circle code channel and the third circle code channel correspond one to one, forming 180 groups of bright and 180 groups of dark marking lines, which change alternately, and each group of marking lines forms an angular deviation of 0.5°.

[0010] The rotating shaft is divided into four sections according to the diameter size, and the diameter changes of the four sections form three shaft shoulders.

[0011] Wherein, the photoelectric speed sensor further comprises: a cover plate and an end cover,

[0012] The cover plate is located on the inner side of the end cover, on the right side of the rotating shaft and the first bearing; the outside of the end cover is connected to the shell and is screwed to the right end inside the shell by threads; the electrical connector is installed on the right side of the end cover; a groove is provided in the middle of the left side of the cover plate, which forms a gap between the cover plate and the rotating shaft.

[0013] The space between the cover plate and the end cover is filled with vulcanized silicone rubber.

[0014] A sealing gasket is provided between the end cover and the electrical connector, and the sealing gasket is made of aviation oil-resistant asbestos rubber material.

[0015] Among them, four screws are installed on the electrical connector, and washers are provided between the electrical connector and the screws.

[0016] Wherein, a first sealing ring is provided between the shell and the end cover.

[0017] Wherein, a second sealing ring is provided between the housing and the rotating shaft.

[0018] The beneficial effects of the present invention are:

[0019] The product has high redundancy and adopts six-redundancy design, namely three-circle code channel and three parallel circuits, outputting six-way signal Z, B. and A. It can effectively avoid speed measurement failure caused by photoelectric component failure; the resolution is as high as 360Hz / r; the output signal B, and A. A 90° phase difference enables the determination of the forward and reverse rotation of the wheel axle; the light reflective transceiver structure only requires the encoder and the photoelectric base to be aligned, and the alignment requirements are low, which can reduce the machining accuracy requirements and the product assembly process requirements; the encoder has good dustproof properties, and the paint marking line is not easy to fall dust; it is sealed and has good moisture-proof properties, and the front and rear ends of the sensor have an effective moisture-proof design. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of the photoelectric speed sensor provided by the present invention;

[0021] Figure 2 is a cross-sectional view of the shell provided by the present invention;

[0022] Figure 3 It is a schematic diagram of the housing structure provided by the present invention;

[0023] Figure 4This is a schematic diagram of the rotating shaft structure provided by the present invention;

[0024] Figure 5 is a front view of the encoder provided by the present invention;

[0025] Figure 6 is a side view of the encoder provided by the present invention;

[0026] Figure 7 This is a schematic diagram of the structure of the photoelectric base provided by the present invention;

[0027] Figure 8 This is a schematic diagram of the bearing seat structure provided by the present invention;

[0028] Figure 9 is a cross-sectional view of the end cover provided by the present invention;

[0029] Figure 10 It is a side view of the end cover provided by the present invention.

[0030] In the figure: 1-shift fork; 2-rotating shaft; 3-housing; 4-encoder; 5-photoelectric seat; 6-bearing seat; 7-cover plate; 8-end cover; 9-vulcanized silicone rubber; 10-sealing plate; 11-electrical connector; 12-washer; 13-screw (M3); 14-wire; 15-first sealing ring (A21-48×2J1); 16-first bearing (D80025TR2); 17-screw (M2.5); 18-second bearing (D80027T2R2); 19-spring; 20-second sealing ring (A21-6.8×1.7J1); 21-rivet; 22-housing shaft mounting groove; 23-housing second sealing ring mounting groove; 24-housing Body M2.5 threaded hole; 25-housing bearing seat mounting groove; 26-housing first sealing ring mounting groove; 27-housing end cover mounting threaded hole; 28-housing bearing mounting hole; 29-spindle rivet mounting hole; 30-shaft shoulder; 31-shaft shoulder; 32-spindle M2.5 threaded hole; 33-shaft shoulder; 34-code channel one; 35-code channel two; 36-code channel three; 37-encoder screw mounting hole; 38-photoelectric seat screw mounting through hole; 39-photoelectric seat welding wire piece; 40-bearing seat convex key; 41-bearing seat bearing mounting hole; 42-bearing seat threading hole; 43-end cover thread; 44-end cover first sealing ring mounting groove; 45-end cover M3 threaded hole; 46-housing convex key. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below through specific implementation methods and drawings.

[0032] The present invention proposes a photoelectric speed sensor that can be installed in the wheel axle of an airplane, a high-speed train, or a locomotive. The photoelectric speed sensor includes: a shift fork, a rotating shaft, a housing, an encoder, a photoelectric seat, a bearing seat, an electrical connector, a first bearing, and a second bearing.

[0033] The shift fork is installed at the left end of the rotating shaft and is connected to the shift rod of the wheel axle of the external device; the external main body of the shell is sleeved in the wheel axle of the external device, and the shell flange is installed at one end of the wheel axle of the external device to achieve axial and angular fixation of the shell and the external device; the first bearing is installed on the bearing seat; the second bearing is installed at the left end inside the shell; the rotating shaft is installed inside the shell, the right end of the rotating shaft is sleeved in the first bearing, and the left end of the rotating shaft is sleeved in the second bearing; the photoelectric seat is installed inside the shell, and the photoelectric seat is electrically connected to the electrical connector; the bearing seat is installed at the right end inside the shell; the encoder is sleeved on the rotating shaft, and the encoder is located on the left side inside the photoelectric seat.

[0034] The internal circuit of the photoelectric seat includes three parallel circuits, each circuit is equipped with two groups of photoelectric elements. The positions of the photoelectric elements in the three circuits correspond to the positions of the three-circle code tracks on the encoder: the two groups of photoelectric elements on the first circuit generate output signals Z, The two groups of photoelectric elements on the second circuit generate output signals B, The two groups of photoelectric elements in the third circuit generate output signals A,

[0035] The encoder is marked with three circles of code tracks on its circumference. The first circle of code tracks has a marking line, which is consistent with the output signal Z, Correspondingly, the resolution is 1Hz / r; the second circle code channel has 180 groups of marking lines, forming 180 groups of light and dark alternating changes, with an angular direction of 2° as a cycle, and output signal B, Correspondingly, the resolution is 180Hz / r; the third circle code channel has 180 groups of marking lines, forming 180 groups of light and dark alternating changes, with an angular direction of 2° as a cycle, and the output signal A, Correspondingly, the resolution is 180Hz / r; the marking lines of the second circle code channel and the third circle code channel correspond one to one, forming 180 groups of bright and 180 groups of dark marking lines, which change alternately, and each group of marking lines forms an angular deviation of 0.5°.

[0036] The photoelectric speed sensor further includes a cover plate and an end cap. The cover plate is located inside the end cap, to the right of the rotating shaft and the first bearing. The end cap is externally connected to the housing and is screwed to the right end of the housing. An electrical connector is mounted on the right side of the end cap. A groove is defined in the center of the left side of the cover plate, creating a gap between the cover plate and the rotating shaft. The space between the cover plate and the end cap is filled with vulcanized silicone rubber.

[0037] A sealing gasket is provided between the end cover and the electrical connector. For example, the sealing gasket may be made of aviation oil-resistant asbestos rubber material.

[0038] Furthermore, a first sealing ring may be provided between the housing and the end cover, and a second sealing ring may be provided between the housing and the rotating shaft.

[0039] An embodiment of the present invention provides a photoelectric speed sensor, such as Figures 1 to 10 As shown, the photoelectric speed sensor includes: a shift fork 1, a rotating shaft 2 (see Figure 4 ), shell 3 (see Figure 2 and Figure 3 ), encoder 4 (see Figure 5 and Figure 6 ), Photoelectric seat 5 (see Figure 7 ), bearing seat 6 (see Figure 8 ), cover plate 7, end cover 8 (see Figure 9 and Figure 10 ), vulcanized silicone rubber 9, sealing gasket 10, electrical connector 11, washer 12, screw (M3) 13, wire 14, first sealing ring (A21-48×2J1) 15, first bearing (D80025TR2) 16, screw (M2.5) 17, second bearing (D80027T2R2) 18, spring 19, second sealing ring (A21-6.8×1.7J1) 20 and rivet 21.

[0040] The second sealing ring (A21-6.8×1.7J1) 20 is installed in the second sealing ring installation groove 23 of the housing. The spring 19 is installed in the housing bearing installation hole 28, and one side of the spring 19 is in contact with the housing 3.

[0041] The second bearing (D80027T2R2) 18 is pressed in from the left end of shaft 2 and contacts shoulder 30. The encoder 4 is pressed in from the right end of shaft 2 and contacts shoulder 31. The screw (M2.5) 17 passes through encoder screw mounting hole 37 and is screwed into the M2.5 threaded hole 32 of the shaft. The first bearing (D80025TR2) 16 is pressed in from the right end of shaft 2 and contacts shoulder 33.

[0042] The rotating shaft 2, second bearing (D80027T2R2) 18, encoder 4, and first bearing (D80025TR2) 16 are installed in the housing 3. Rivet 21 passes through the through-holes of the shift fork 1 and the rotating shaft 2, connecting and securing the shift fork 1 and the rotating shaft 2. A 45° × 1mm chamfer is designed on the left end of the rotating shaft 2 to prevent the second bearing (D80027T2R2) 18 from being scratched when pressed into the rotating shaft 2. This also prevents the second sealing ring (A21-6.8 × 1.7J1) 20 from being scratched when the rotating shaft 2 is installed in the housing's rotating shaft mounting groove 22. The second sealing ring (A21-6.8 × 1.7J1) 20 is compressed by the housing 3 and the rotating shaft 2, forming a seal at the left end of the photoelectric speed sensor, preventing dust, water vapor, and other substances from entering the interior of the housing 3. The second bearing (D80027T2R2) 18 is installed in the housing bearing mounting hole 28. The spring 19 contacts the housing 3 on one side and the second bearing (D80027T2R2) 18 on the other side. The second bearing (D80027T2R2) 18 contacts the spring 19 on one side and the shaft shoulder 30 on the other side.

[0043] There are nine wires 14, labeled ①, ②, ③, ..., ⑧, ⑨. Nine photocell soldering lugs 39 are designed on the photocell 5, labeled ①, ②, ③, ..., ⑧, ⑨. The nine wires 14 are connected to the nine photocell soldering lugs 39 via soldering. Wire ① connects to signal Z, wire ② connects to signal Z(-), wire ③ connects to ground, wire ④ connects to signal B, wire ⑤ connects to signal B(-), wire ⑥ connects to signal A, wire ⑦ connects to signal A(-), wire ⑧ connects to the power supply voltage signal, and wire 9 connects to the shield signal. A, A(-), B, B, Z, and Z(-) are all square wave voltage signals.

[0044] The center through-hole of the photoelectric base 5 passes through the first bearing (D80025TR2) 16 and the rotating shaft 2. Three screws (M2.5) 17 pass through the photoelectric base screw mounting through-hole 28 and are screwed into three corresponding M2.5 threaded holes 24 in the housing to secure the photoelectric base 5 to the housing 3. The distance between the photoelectric base 5 and the code track marking surface of the encoder 4 is 1.2 mm.

[0045] In combination with the wheel speed detection requirements of airplanes, high-speed trains, locomotives, etc., the photoelectric speed sensor of the present invention adopts a six-redundant design, that is, three circles of code channels and three parallel circuits. Each circuit is equipped with two groups of photoelectric elements. The two groups of photoelectric elements on the first circuit generate output signals Z, The two groups of photoelectric elements on the second circuit generate output signal B. The two groups of photoelectric elements on the third circuit generate output signals A, The photoelectric speed sensor of the present invention can output six groups of signals simultaneously, which can effectively avoid speed measurement failure caused by failure of a certain photoelectric element.

[0046] The encoder 4 is designed with three code channels, namely code channel 1 34, code channel 2 35 and code channel 3 36. Code channel 1 34 has a marking line corresponding to the output signal Z, The resolution is 1Hz / r; Channel 2 35 contains 180 groups of marking lines, forming 180 groups of light and dark alternating changes, with an angular direction of 2° as a cycle, corresponding to the output signal B, The resolution is 180Hz / r; Channel 36 contains 180 groups of marking lines, forming 180 groups of light and dark alternating changes, with an angular direction of 2° as a cycle, corresponding to the output signal A, The resolution is 180Hz / r. The marking lines in code channel 2 35 and code channel 3 36 are arranged one by one, forming 180 groups of bright and 180 groups of dark marking lines, which alternate between bright and dark. Each group of marking lines forms an angular difference of 0.5°. Three parallel circuits are designed in the photoelectric base 5, and two groups of photoelectric elements are designed in each circuit. In the first circuit, the positions of the two groups of photoelectric elements are aligned with code channel 1 34, generating output signals Z, In the second circuit, the positions of the two sets of photoelectric elements are aligned with code channel 2 35, generating output signal B, In the third circuit, the positions of the two sets of photoelectric elements are aligned with code channel 36, generating output signals A, 0.5° angular difference can achieve B, Signal and A, The 90° phase difference of the signal can be used to determine whether the wheel axle is rotating forward or reverse.

[0047] The marking lines in channel 1 34, channel 2 35 and channel 3 36 are painted. The markings are smooth and not easy to get dusty. They have a good dustproof effect and can avoid the speed measurement failure caused by dust falling on the grating hole of the encoder disk in traditional photoelectric speed sensors. The use of paint marking lines has fine scales and is conducive to improving the resolution of the sensor. and 180 Group B, There is a 90° phase difference in the signals, so the resolution of the sensor is 360Hz / r, which is much higher than that of traditional electromagnetic speed sensors and transmissive photoelectric speed sensors.

[0048] The bearing mounting hole 41 passes through the first bearing (D80025TR2) 16 and contacts the outer surface of the first bearing (D80025TR2) 16. Two bearing seat keyways 40 are designed on the bearing seat 6, and two housing bearing seat mounting grooves 25 are designed on the housing 3. The two bearing seat keyways 40 are respectively installed in the two housing bearing seat mounting grooves 25. A φ5 through-hole is designed in the bearing seat 6, and the wire 14 passes through the φ5 through-hole.

[0049] Cover plate 7 is installed in end cap 8. The first sealing ring (A21-48×2J1) 15 is installed in the first sealing ring mounting groove 44 of the end cap. The end cap thread 43 is screwed into the housing end cap mounting threaded hole 27. The first sealing ring (A21-48×2J1) 15 is compressed by the end cap 8 and housing 3, forming a seal at the right end of the photoelectric speed sensor, preventing dust, water vapor, and other substances from entering the interior of housing 3. A φ13×1mm groove is designed in cover plate 7 to prevent contact with and friction on the rotating shaft 2 after installation. A φ5 through-hole is designed in end cap 8, through which wire 14 passes.

[0050] The vulcanized silicone rubber 9 is filled between the cover plate 7 and the end cap 8 to form a sealing structure at the right end of the photoelectric speed sensor, which can prevent dust, water vapor, etc. from entering the interior of the housing 3. In addition, the filling of the vulcanized silicone rubber 9 can fix the wire 14 and the angular position of the cover plate 7.

[0051] End cap 8 is designed with four M3 threads. Four screws (M3) 13 pass through four through holes in electrical connector 11 and are screwed into four M3 threaded holes 45 in the end cap to achieve the connection and fixation between electrical connector 11 and end cap 8. The structure of electrical connector 11 can be referred to in related art and will not be described in detail here.

[0052] Sealing plate 10 is installed between electrical connector 11 and end cap 8 to prevent dust, water vapor, etc. from entering housing 3. Washer 12 is installed between electrical connector 11 and screw (M3) 13 to prevent the screw from loosening. Nine wires 14 are labeled ①, ②, ③, ..., ⑧, ⑨, and are connected to pins a, b, c, ..., h, and i of electrical connector 11, respectively.

[0053] The photoelectric speed sensor is fixed to the wheel axle via a housing key 46. The shift lever on the wheel axle inserts into the U-shaped groove of the shift fork 1. When measuring the wheel speed of an aircraft, high-speed train, or locomotive, the shift lever on the wheel axle rotates the sensor's shift fork, shaft, and encoder. As the encoder 4 rotates, light emitted by the photoelectric base 5 reaches the various light bands on the encoder 4, forming six sets of alternating light and dark light patterns. This light is then reflected back to the photoelectric base 5. The photoelectric base receives the light and senses the changes in light and dark, outputting an alternating current signal. This signal is converted into a square wave signal by a Schmitt trigger and then output to the control box via electrical connector 11. The structure of the control box can be referenced in related art. The control box calculates the wheel speed of an aircraft, high-speed train, or locomotive by counting and calculating over a period of time. This light-reflecting transceiver structure requires only alignment of the encoder and photoelectric base, which is a low requirement, reducing machining precision and product assembly requirements.

[0054] The above merely describes the embodiments of the present invention, and while the description is relatively specific and detailed, it should not be construed as limiting the scope of the invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the scope of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Furthermore, any portions not described in detail herein are conventional techniques.

Claims

1. A photoelectric speed sensor, characterized in that: include: Shift fork, rotating shaft, housing, encoder, photoelectric seat, bearing seat, electrical connector, first bearing and second bearing, The shift fork is mounted on the left end of the rotating shaft and connected to the shift lever of the external device wheel shaft; the external main body of the housing is sleeved in the external device wheel shaft, and the housing flange is mounted on one end of the external device wheel shaft to achieve axial and angular fixation of the housing and the external device; the first bearing is mounted on the bearing seat; the second bearing is mounted on the left end of the interior of the housing; the rotating shaft is mounted in the interior of the housing, the right end of the rotating shaft is sleeved in the first bearing, and the left end of the rotating shaft is sleeved in the second bearing; the photoelectric seat is mounted in the interior of the housing, and the photoelectric seat is electrically connected to the electrical connector; the bearing seat is mounted on the right end of the interior of the housing; the encoder is sleeved on the rotating shaft, and the encoder is located on the left side of the interior of the photoelectric seat; The internal circuit of the photoelectric base includes three parallel circuits, each circuit is provided with two groups of photoelectric elements, and the positions of the photoelectric elements in the three circuits correspond to the positions of the three code tracks on the encoder: the two groups of photoelectric elements on the first circuit respectively generate output signals Z and Z-, the two groups of photoelectric elements on the second circuit respectively generate output signals B and B-, and the two groups of photoelectric elements on the third circuit respectively generate output signals A and A-; There are three circles of code tracks marked with paint on the circumference of the encoder. The first circle of code tracks is provided with a marking line, corresponding to the output signals Z and Z-, with a resolution of 1Hz / r; the second circle of code tracks is provided with 180 groups of marking lines, forming 180 groups of light and dark alternating changes, with an angular direction of 2° as a cycle, corresponding to the output signals B and B-, with a resolution of 180Hz / r; the third circle of code tracks is provided with 180 groups of marking lines, forming 180 groups of light and dark alternating changes, with an angular direction of 2° as a cycle, corresponding to the output signals A and A-, with a resolution of 180Hz / r; the marking lines of the second and third circle of code tracks correspond one to one, forming 180 groups of light and 180 groups of dark marking lines, alternating between light and dark, and each group of marking lines forms an angular deviation of 0.5°.

2. The photoelectric speed sensor according to claim 1, characterized in that The rotating shaft is divided into four sections according to the diameter, and the diameter changes of the four sections form three shaft shoulders.

3. The photoelectric speed sensor according to claim 1, wherein: The photoelectric speed sensor further comprises: a cover plate and an end cap, The cover is located on the inside of the end cover, to the right of the rotating shaft and the first bearing; the outside of the end cover is connected to the shell and is screwed to the right end inside the shell by threads; the electrical connector is installed on the right side of the end cover; a groove is provided in the middle of the left side of the cover, which forms a gap between the cover and the rotating shaft.

4. The photoelectric speed sensor according to claim 3, characterized in that The space between the cover plate and the end cover is filled with vulcanized silicone rubber.

5. The photoelectric speed sensor according to claim 3, characterized in that A sealing pad is provided between the end cover and the electrical connector, and the sealing pad is made of aviation oil-resistant asbestos rubber material.

6. The photoelectric speed sensor according to claim 1, characterized in that Four screws are installed on the electrical connector, and washers are provided between the electrical connector and the screws.

7. The photoelectric speed sensor according to claim 3, characterized in that A first sealing ring is provided between the shell and the end cover.

8. The photoelectric speed sensor according to claim 1, characterized in that A second sealing ring is provided between the housing and the rotating shaft.

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