An overloaded redundant optoelectronic encoder

Abstract

An overloaded redundant photoelectric encoder belongs to the field of automation technology and includes a flange, an encoder bushing, scanning LED I, scanning LED II, static grating I, static grating II, photoelectric receiving device I, photoelectric receiving device II, a circuit board, a hollow shaft, a junction box housing, a cable sealing joint I, a moving grating, a locking nut, overloaded hybrid bearing I, overloaded hybrid bearing II, and a cable sealing joint II. The present invention has two sets of independent encoder systems, achieving redundant design within the same encoder mechanical parts; a set of dual overloaded hybrid bearings is equipped in the shafting, which can avoid the discharge between the shaft and the electronic devices on the circuit board under high pressure and can bear large radial and axial loads at the same time. The present invention has a reasonable structure, is easy to assemble, has a high protection level, and the whole machine reaches IP66, protecting the encoder from the intrusion of dust, oil, and liquid, and is suitable for the detection of speed loops and position loops in heavy industrial automation equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of automation, and particularly relates to a heavy-duty redundant photoelectric encoder. Background Art

[0002] Photoelectric encoders are essential key components in industrial automation and are widely used in various industries such as machinery, machine tool manufacturing, mining, metallurgy, automobiles, ships, and construction. The servo systems, generators, etc. of heavy-duty automation equipment will apply encoders to achieve the detection of speed loops and position loops. Based on the feedback information of the encoders, the corresponding speed and position are analyzed, compared with the target, and a judgment is made to give the next working instruction to the execution unit. Due to the harsh application environment, being in conditions such as dust, vibration, rain, and oil for a long time, higher requirements are put forward for the stability, accuracy, anti-mechanical damage ability, and protection level of the encoders. Considering aspects such as personnel safety and equipment safety of heavy-duty equipment, the system is required to have high reliability. The existing technical solution is to install two encoders on one main shaft. When one of the encoders fails, the system switches to the other encoder. Although this solution can achieve the redundant design of the system, the number of encoders used doubles, which not only takes up space but also increases the cost.

[0003] In recent years, some domestic encoder enterprises have launched split-type encoders in order to improve the main shaft load capacity of the encoders. The shell, main body, main shaft, bearings, etc. of the encoders are omitted and are divided into two parts: a reading head and a code disk, which are installed and debugged on-site. This method omits the shafting structure of the encoder and successfully avoids the damage to the encoder bearings caused by excessive shafting load. However, other problems have arisen. Key parameters such as the axial clearance and radial distance between the code disk and the reading head have become variables, and the proficiency of the installation personnel directly affects the accuracy and installation efficiency of the encoder. This encoder has an open structure and no protection unit, and cannot adapt to the application environment of heavy-duty equipment. At best, the accuracy of the encoder deteriorates, and at worst, the encoder fails. Customers can make up for this problem by installing a protective cover, but this not only takes up space but also increases the application cost.

[0004] Therefore, there is an urgent need for a new technical solution in the existing technology to solve this problem. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: to provide a heavy-duty redundant photoelectric encoder to solve the technical problems that two encoders are used in existing heavy-duty automation equipment to achieve redundant design, which not only takes up space but also increases the cost; and split-type encoders cannot adapt to the application environment of heavy-duty equipment.

[0006] An overloaded redundant photoelectric encoder, comprising a flange, an encoder bushing, scanning LED I, scanning LED II, static grating I, static grating II, photoelectric receiving device I, photoelectric receiving device II, a circuit board, a hollow shaft, a junction box housing, a cable sealing joint I, a moving grating, a locking nut, overloaded hybrid bearing I, overloaded hybrid bearing II, and a cable sealing joint II,

[0007] The encoder bushing is sleeved outside the hollow shaft and is rotationally connected to the hollow shaft. Two cavities are provided on the inner side wall of the encoder bushing, and overloaded hybrid bearing I and overloaded hybrid bearing II are respectively placed in the two cavities. Two sets of independent encoder systems are fixedly installed at a fixed angle on the outside of one end of the encoder bushing; the hollow shaft passes through the inner holes of overloaded hybrid bearing I and overloaded hybrid bearing II and is fixed by a locking nut. One end of the hollow shaft is sleeved into the customer shaft to the root of the customer shaft, and the other end of the hollow shaft is fixedly connected to the end of the customer shaft by an inner hexagon screw;

[0008] In the two sets of independent encoder systems, the scanning LED I, the static grating I, and the photoelectric receiving device I arranged in sequence are one set, and the scanning LED II, the static grating II, and the photoelectric receiving device II arranged in sequence are the other set; the moving grating is fixedly connected to the locking nut; the circuit board is installed on the outer wall of the encoder bushing through a bracket, and the circuit board is electrically connected to the scanning LED I, the scanning LED II, the photoelectric receiving device I, and the photoelectric receiving device II respectively;

[0009] The flange is sleeved outside the encoder bushing, and the flange is fixedly connected to the junction box housing by screws at the distal end port of the customer shaft; both the cable sealing joint I and the cable sealing joint II are installed in the threaded holes of the flange, and an external cable is inserted into the cable sealing joint I and the cable sealing joint II; the external cable is connected to the circuit board through a terminal.

[0010] An overloaded redundant photoelectric encoder is further provided with a torque arm bracket, one end of the torque arm bracket is fixedly connected to the flange, and the other end of the torque arm bracket is fixedly connected to the customer host.

[0011] An oil seal is provided on the flange.

[0012] A sealing groove is provided at the connection of the hollow shaft and the root of the customer shaft; a sealing ring is installed in the sealing groove.

[0013] Two separate signal processing circuits and two separate light emission control circuits are provided on the circuit board.

[0014] Through the above design, the present invention can bring the following beneficial effects:

[0015] 1. The structure of the present invention is reasonable, easy to assemble, and has a high protection level. The whole machine reaches IP66, protecting the encoder from the intrusion of dust, oil, and liquid. It is applicable to the automation equipment in heavy industry for realizing the detection of speed loop and position loop.

[0016] 2. The present invention realizes redundant design within the same encoder mechanical parts, with two sets of independent scanning LEDs and circuit systems, improving the reliability of the application system.

[0017] 3. The shafting of the present invention is equipped with a set of double heavy-duty hybrid bearings, which can avoid the discharge between the shaft and the electronic devices on the circuit board under the voltage condition of up to 2.8 KV, and can also bear large radial and axial loads, meeting the normal operation under the conditions of axial load ≤ 550 N and radial load ≤ 1300 N.

[0018] 4. The present invention can operate continuously at extreme temperatures from -40°C to +100°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following further describes the present invention in conjunction with the drawings and specific embodiments:

[0020] Figure 1 It is a schematic cross-sectional structure diagram of a heavy-duty redundant photoelectric encoder of the present invention.

[0021] Figure 2 It is a schematic diagram of one end structure of a heavy-duty redundant photoelectric encoder of the present invention.

[0022] Figure 3 It is a schematic diagram of the other end structure of a heavy-duty redundant photoelectric encoder of the present invention.

[0023] In the figure, 1 - customer shaft, 2 - oil seal, 3 - flange, 4 - encoder bushing, 5 - scanning LED Ⅰ, 6 - scanning LED Ⅱ, 7 - static grating Ⅰ, 8 - static grating Ⅱ, 9 - photoelectric receiving device Ⅰ, 10 - photoelectric receiving device Ⅱ, 11 - circuit board, 12 - hollow shaft, 13 - hexagon socket head cap screw, 14 - junction box housing, 15 - cable sealing joint Ⅰ, 16 - moving grating, 17 - locking nut, 18 - heavy-duty hybrid bearing Ⅰ, 19 - heavy-duty hybrid bearing Ⅱ, 20 - sealing ring, 21 - cable sealing joint Ⅱ, 22 - screw, 23 - torque arm bracket, 24 - fastening screw. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following further describes the embodiments of the present invention in conjunction with the drawings:

[0025] From the attached Figure 1 、 2, as shown in Figures 3: Heavy-duty hybrid bearings 18 and 19 are installed on the encoder bushing 4. The stainless steel hollow spindle 12 is inserted into the inner holes of the heavy-duty hybrid bearings 18 and 19, and fixed with a lock nut 17 to the self-thread of the stainless steel hollow spindle 12. The inner and outer rings of the heavy-duty hybrid bearings are non-conductive, which plays an insulating role between the stainless steel hollow spindle 12 and the encoder bushing 4 and can withstand a voltage of 2.8 KV. The balls of the selected heavy-duty hybrid bearings are made of ceramic material, and the inner and outer rings are made of steel. They are strong and able to withstand high loads while ensuring insulation, and can operate normally under the conditions of axial load ≤ 550 N and radial load ≤ 1300 N. Two sets of independent encoder systems are assembled onto the bushing 4 at a 90-degree angle. Among them, the scanning LED Ⅰ 5, the static grating Ⅰ 7, and the photoelectric receiving device Ⅰ 9 are one set, and the scanning LED Ⅱ 6, the static grating Ⅱ 8, and the photoelectric receiving device Ⅱ 10 are another set. The LED Ⅰ 5 and the scanning LED Ⅱ 6 are assembled onto the bushing 4 and emit infrared parallel light, which respectively pass through the corresponding static grating Ⅰ 7 and static grating Ⅱ 8 fixed on the encoder bushing 4 and the moving grating 16 fixed on the stainless steel hollow spindle 12. The photoelectric receiving device Ⅰ 9 and the photoelectric receiving device Ⅱ 10 respectively convert their own optical signals into electrical signals by two separate signal processing circuits and two separate light-emitting control circuits on the circuit board 11 to achieve redundancy.

[0026] The assembly of the above components is installed into the flange 3 through the fastening screw 24. The flange 3 and the junction box housing 14 are made of a sturdy aluminum protective cover. The O-ring 20 is installed in the sealing groove of the stainless steel hollow shaft 12. The oil seal 2 is pushed into the installation position of the flange 3. The junction box housing 14 is fixed to the flange 3 through the screw 22. The cable sealing joints 15 and 21 are installed in the threaded holes of the flange 3. This structure realizes shaft sealing, cable sealing, and housing sealing, is sturdy and durable, and the overall protection level reaches IP66.

[0027] During use, first remove the junction box housing 14. The customer shaft 1 is inserted into the stainless steel hollow shaft 12 of the encoder. The root of the customer shaft 1 is in close contact with the sealing ring 20 at the end of the stainless steel spindle 12 to ensure shaft sealing. Use M5 or M6 hexagon socket head cap screws 13 and the matching flat washers to pass through the holes on the stainless steel spindle 12 to fix the customer shaft 1 to the stainless steel hollow shaft 12 of the encoder. Pass the external cable through the cable sealing joint Ⅰ 15 and the cable sealing joint Ⅱ 21 and install it on the terminal of the circuit board 11, and then install the junction box housing 14 onto the flange 3. The encoder flange 3 is fixed to the customer host through the torque arm bracket 23.

Claims

1. An overloaded redundant optoelectronic encoder, characterized in that: It includes a flange (3), an encoder bushing (4), a scanning LED I (5), a scanning LED II (6), a static grating I (7), a static grating II (8), a photoelectric receiving device I (9), a photoelectric receiving device II (10), a circuit board (11), a hollow shaft (12), a junction box housing (14), a cable sealing joint I (15), a moving grating (16), a locking nut (17), a heavy-duty hybrid bearing I (18), a heavy-duty hybrid bearing II (19), and a cable sealing joint II (21). The encoder bushing (4) is sleeved outside the hollow shaft (12) and is rotationally connected to the hollow shaft (12). There are also two cavities provided on the inner side wall of the encoder bushing (4), and a heavy-duty hybrid bearing I (18) and a heavy-duty hybrid bearing II (19) are respectively placed in the two cavities. Two sets of independent encoder systems are fixedly installed at a fixed angle on the outside of one end of the encoder bushing (4); the hollow shaft (12) penetrates into the inner holes of the heavy-duty hybrid bearing I (18) and the heavy-duty hybrid bearing II (19) and is fixed by a locking nut (17). One end of the hollow shaft (12) is sleeved into the customer shaft (1) to the root of the customer shaft (1), and the other end of the hollow shaft (12) is fixedly connected to the end of the customer shaft (1) by an inner hexagon screw (13). In the two sets of independent encoder systems, the scanning LED I (5), the static grating I (7), and the photoelectric receiving device I (9) arranged in sequence are one set, and the scanning LED II (6), the static grating II (8), and the photoelectric receiving device II (10) arranged in sequence are the other set; the moving grating (16) is fixedly connected to the locking nut (17); the circuit board (11) is installed on the outer wall of the encoder bushing (4) through a bracket, and the circuit board (11) is electrically connected to the scanning LED I (5), the scanning LED II (6), the photoelectric receiving device I (9), and the photoelectric receiving device II (10) respectively. The flange (3) is sleeved outside the encoder bushing (4), and the flange (3) is fixedly connected to the junction box housing (14) by screws (22) at the distal end port of the customer shaft (1); both the cable sealing joint I (15) and the cable sealing joint II (21) are installed in the threaded holes of the flange (3), and an external cable is inserted into the cable sealing joint I (15) and the cable sealing joint II (21); the external cable is connected to the circuit board (11) through a terminal.

2. The overload redundant photoelectric encoder according to claim 1, wherein: A torque arm bracket (23) is also provided. One end of the torque arm bracket (23) is fixedly connected to the flange (3), and the other end of the torque arm bracket (23) is fixedly connected to the customer host.

3. The overload type redundant optoelectronic encoder according to claim 1, characterized in that: An oil seal (2) is provided on the flange (3).

4. The heavy-duty redundant photoelectric encoder according to claim 1, characterized in that: A sealing groove is provided at the connection of the hollow shaft (12) with the root of the customer shaft (1); a sealing ring (20) is installed in the sealing groove.

5. The heavy-duty redundant photoelectric encoder according to claim 1, characterized in that: Two separate signal processing circuits and two separate light emission control circuits are provided on the circuit board (11).

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