Split type multi-circle magnetoelectric absolute position measuring device

Abstract

The invention discloses a split type multi-circle magnetoelectric absolute position measuring device, and belongs to the technical field of position measurement. The device comprises a base, a shell, a main rotating shaft, magnetic steel, a supporting plate, a gear reducer and a circuit board, a driving gear shaft and a gear reducer driven gear shaft meshed with the driving gear shaft serve as input, the tail end of a main shaft is inserted into a motor shaft and fastened from the upper portion through a screw, and the upper end of the driven gear shaft is connected with the supporting plate while the lower end of the driven gear shaft is connected with the base. According to the position measuring device, the split structure design and axial and circumferential positioning are realized, the risk that the structure of the speed reducer is damaged or stuck due to axial play displacement in the rotating process of the motor is effectively solved, the reliability and stability of the position measuring device are improved, and the actual angle information of the rotation of the motor is accurately output.

Description

Technical Field

[0001] The invention relates to a split multi-turn magnetoelectric absolute position measuring device, belonging to the technical field of position measurement. Background Art

[0002] As a high-precision position sensor, the multi-turn magnetoelectric absolute position measurement device is combined with digital control to convert physical signals such as position angle and speed in the control system into voltage signals for position detection and motion control. It is an important part of the servo electromechanical control system. During the movement of the servo motor, axial movement sometimes occurs, which can easily affect the accuracy of the position encoder and requires the position sensor to be resistant to shock and vibration.

[0003] The high-precision position sensors on the domestic and foreign markets are mainly multi-turn absolute encoders that use optical (magnetic) electric code disks and micro reducers. Because there is a gap in the rotating shaft of the encoder reducer, the rotating shaft is easily affected by external vibrations and produces vibrations during operation, causing the encoder value to shift out of position. In addition, due to the lateral force pulling the axis, if there is a deviation in the installation concentricity, the faster the spindle rotates, the greater the horizontal tension and the higher the runout, and the higher the damage rate.

[0004] Chinese patent CN211740239U discloses a mechanical multi-turn absolute encoder, in which the gear shaft of the reducer adopts a cantilever arrangement. The advantage is that the structure is simple, but the disadvantage is that the upper end of the gear shaft is not sufficiently constrained, and due to the large number of gear shafts, axial movement is prone to occur, and the impact resistance is poor, and it is easy to be damaged during rotation. Chinese patent CN208252620U discloses an improved encoder shaft structure, in which two O-type rubber sealing ring structures are added to the shaft of the encoder to prevent the encoder from being affected by vibration and producing uncertain swings. The advantages are that the number of parts is reduced and the assembly is simple and fast. The disadvantage is that the impact and vibration resistance is limited and the axial movement cannot be solved. In summary, the cantilever structure arrangement of the reducer brings about the problem of axial movement, the axial movement and angular swing caused by the deviation of the concentricity of the encoder during installation, and the problem of spindle clearance, which easily leads to the problem that the rotation speed is not synchronized with the input rotation speed, thereby affecting the accuracy of the encoder. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a split multi-turn magnetoelectric absolute position measurement device, which effectively solves the axial displacement during the rotation of the motor through the split structure design and the axial and circumferential positioning of the gear reducer, thereby improving the reliability and stability of the position measurement device.

[0006] The technical solution of the present invention is:

[0007] A split multi-turn magnetoelectric absolute position measuring device comprises a base, a housing, a main shaft, a magnetic steel, a support plate, a gear reducer and a circuit board;

[0008] The base is a two-layer boss structure with a through hole in the center, and multiple gear reducer mounting holes, positioning holes, and threaded holes are provided between the through hole and the edge;

[0009] The outer shell is a barrel-shaped structure with an opening at the bottom, and the opening end is fixedly connected to the base;

[0010] The main shaft of the main rotating shaft passes through the through hole of the base, and the tail end is inserted into the motor shaft and fastened; the gear of the main rotating shaft is meshed with the gear reducer to form a split structure;

[0011] The support plate is mounted on the first-stage boss of the base, and the lower end surface coincides with the upper end surface of the first-stage boss; a plurality of positioning holes are arranged on the support plate, which are the same in number, size and position as the mounting holes of the gear reducer on the base;

[0012] The gear reducer comprises more than two driven gear shafts connected in sequence, and the two ends of each driven gear shaft are respectively placed in the corresponding positioning holes and gear reducer mounting holes on the support plate and the base; grooves are provided on the upper surfaces of two of the driven gear shafts, and a magnet is placed in each groove;

[0013] The two magnets are used to measure the single-turn angle and number of turns of the driven gear shaft.

[0014] The circuit board is fixed on the upper surface of the support plate and is equipped with a signal processing module and multiple magnetic induction chips; the number of magnetic induction chips is the same as the number of magnets, each magnetic induction chip records the magnetic field signal of a magnet, and the signal processing module processes the magnetic field signal and outputs the actual angle information of the motor rotation.

[0015] Furthermore, the base is provided with a plurality of positioning holes, gear shaft mounting holes, and threaded holes between the central through hole and the edge, each positioning hole is used for guiding and positioning between the support plate, the base, and the circuit board, thereby improving the coaxiality between the gear reducer and the magnetically sensitive chip on the circuit board; each gear shaft mounting hole is used to connect each driven gear shaft on the gear reducer, and the end face of the gear mounting hole is higher than the bottom surface of the base; the threaded holes include upper threaded holes and lower threaded holes, the lower threaded holes are used for fastening the outer shell, and the upper threaded holes are used for fastening the support plate.

[0016] Furthermore, the lower shoulder end face of each driven gear shaft coincides with the end face of the second-stage boss on the base to achieve axial positioning.

[0017] Furthermore, the reduction ratio of the driven gear shaft on which the magnetic steel is placed is a multiple of 2.

[0018] Furthermore, the central through hole of the base is arranged concentrically with the main axis of the main rotating shaft, and the diameter of the central through hole of the base is larger than the diameter of the main axis, and the upper end surface of the main axis is flush with the upper end surface of the support plate.

[0019] Furthermore, a boss is provided on the lower edge of each positioning hole on the support plate, and the boss coincides with the shaft shoulder at the upper end of the driven gear shaft to achieve axial fixation.

[0020] Furthermore, grooves are provided on the upper surfaces of the three driven gear shafts, and a magnet is placed in each groove; two of the driven gear shafts have the same structure, and the placed magnets are used to measure the single-turn rotation angle of the driven gear shafts, thereby realizing dual redundant measurement; the magnet on the third driven gear shaft is used to measure the number of turns of the driven gear shaft;

[0021] The signal processing module on the circuit board averages the single-turn angle information sensed by the two magnetic induction chips, and then integrates it with the number of turns into an actual code value. After converting the actual code value, the actual angle information of the motor rotation is obtained.

[0022] Furthermore, each driven gear shaft is provided with two gears distributed in upper and lower layers.

[0023] Furthermore, the magnetic induction chips on the circuit board correspond to the positions of the magnetic steels one by one and are placed coaxially opposite to each other to enhance the magnetic induction strength.

[0024] Furthermore, the gear reducer adopts the principle that the gear diameter is small at the front and large at the back, that is, the transmission ratio is distributed according to the principle that the gear diameter gradually increases from the high speed stage to the low speed stage.

[0025] The advantages of the present invention compared with the prior art are:

[0026] (1) The present invention adopts a split structure design, with a driving gear shaft and a driven gear shaft meshing with the driving gear shaft as input, the tail end of the main shaft is inserted into the motor shaft and fastened from the top with screws, and the driven gears are distributed on the circumference of the base, realizing a split structure design, effectively solving the axial displacement of ±2mm during the rotation of the motor, which brings the risk of damage or jamming of the reducer structure, and improving the reliability and stability of the position measurement device.

[0027] (2) The gear reducer in the present invention is designed with an upper and lower integrated support structure, which is stable and reliable compared to the cantilever beam structure. A support plate structure is designed at the upper end of the gear shaft, and a threaded hole and a pin hole are designed on the base boss at the lower end for fixed axial positioning, thereby improving the impact resistance of the gear system.

[0028] (3) All gear shaft systems in the present invention adopt axial and circumferential positioning designs. The two ends of the gear shaft are respectively placed in the corresponding through holes on the support plate and the base for circumferential positioning, and the axial positioning design is performed through the bottom plate boss, the boss on the lower end surface of the support plate, and the upper and lower shoulders of each driven gear shaft, thereby realizing an integrated structural design of the gear system and the base, improving the vibration resistance of the position measurement device, and effectively ensuring the measurement accuracy and stability in a vibration environment.

[0029] (4) The present invention adopts a dual redundant structure design with a structural envelope range of Φ22.5×50mm. It has a simple structure and is easy to assemble and install. The redundant structure design improves reliability and effectively reduces the risk of measurement failure caused by damage or failure of one of the magnetic steels due to uncertain factors.

[0030] (5) The reduction ratio of the gear reducer in the present invention is designed as an integer multiple of 2, which avoids the complex floating-point operations of the system and directly performs binary shift operations, thereby improving the MCU data update speed and transmission speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0032] Figure 1 This is an exploded view of a split multi-turn magnetoelectric absolute position measuring device according to an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the structure of a mechanical gear set according to an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the base structure of an embodiment of the present invention;

[0035] Figure 4 Schematic diagram of a split multi-turn magnetoelectric absolute position measurement device according to an embodiment of the present invention;

[0036] Figure 5 It is a schematic diagram of the design of the upper and lower integrated support structures of the gear reducer according to an embodiment of the present invention;

[0037] Figure 6 This is a simplified diagram of the plane distribution of the gear shaft systems of the gear reducer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0039] The present invention proposes a split multi-turn magnetoelectric absolute position measuring device, such as Figure 4 As shown, it includes a base 1, a shell 2, and a split main shaft 3 partially placed in the shell. Figure 1 As shown, a magnetic steel 4, a support plate 5, a gear reducer, a circuit board 6 with a magnetic encoder chip, a pin 7 and a screw 8 are provided.

[0040] Base 1 Figure 3 As shown, there is a through hole in the center of the bottom plate, which is used to constrain the split main shaft 3. A positioning hole 20, a gear shaft mounting hole 21, a lower threaded hole 22, and an upper threaded hole 23 are provided on the base 1. The positioning hole 20 is used for guiding and positioning between the support plate, the base, and the circuit board to improve the coaxiality of the gear reducer and the magnetic sensitive chip on the circuit board. The gear shaft mounting hole 21 is used to connect the driven gear shafts on the gear reducer. The end face of the gear mounting hole 21 is higher than the bottom surface design of the base. The position of each gear mounting hole is calculated by the gear reduction ratio of each level of the gear reducer and the module, number of teeth of the gear and the base diameter. The unique corresponding position is calculated. The lower threaded hole 22 is used to fasten the outer shell, and its position is evenly distributed on the base at 360°. The upper threaded hole 23 is used to fasten the upper support plate, and its position corresponds one-to-one with the upper support plate. The two-stage convex step design is adopted to separate the axial end faces of the driven gears at each level in the gear reducer from the bottom surface of the base, eliminating the friction generated by the contact between the base and the end faces of the driven gears at each level, reducing the rotation time lag of the driven gears at each level and improving the flexibility of the rotation of the driven gears at each level. The base adopts a circumferential segmented guide structure design at the contact point with the shell, which improves the coaxiality of the shell and the base installation, thereby ensuring that the integrated gear reducer can rotate flexibly and smoothly, and improving the reliability and stability of the encoding.

[0041] The gear reducer is located between the support plate 5 and the base 1. Figure 5 The gear reducer is composed of eight gear shafts connected in sequence and connected to the gears on the split main shaft 3, as shown in FIG. Figure 2As shown, the gear shafts are the first driven gear shaft 9, the second driven gear shaft 10, the third driven gear shaft 11, the fourth driven gear shaft 12, the fifth driven gear shaft 13, the sixth driven gear shaft 14, the seventh driven gear shaft 15 and the eighth driven gear shaft 16, and each driven gear shaft is distributed in two layers of gears, and the two ends of each gear shaft are respectively placed in the corresponding through holes on the support plate and the base for circumferential positioning. The overall working space of each level of driven gears, in order to avoid the spatial constraints of mutual interference between gears caused by the two-layer shaft system arrangement, adopts the principle of small front and large rear (i.e. gradually increasing from high speed to low speed) to distribute the transmission ratio, so that each level of intermediate shaft can obtain higher speed and smaller torque, and the size and quality of the shaft and the parts on the shaft are reduced. According to the design requirements of the small modulus reducer, the plane distribution sketch and dynamic diagram of the gear shaft system are determined, as shown in the figure. Figure 6 The speed of the driven gear is set from high to low according to the design of the transmission ratio.

[0042] The upper end faces of the third driven gear shaft 11, the seventh driven gear shaft 15, and the eighth driven gear shaft 16 are all provided with grooves, and three circular magnets 4 are respectively embedded in the three grooves, and the upper end faces of the magnets 4 are flush with the upper end faces of the support plate 5. The magnets 4 rotate with the gear shaft, and the magnetic encoder chips on the circuit board 6 are arranged opposite to the magnets 4 at corresponding intervals. Among them, the magnets 4 installed in the grooves on the third driven gear shaft 11 and the seventh driven gear shaft 15 form a two-redundant design. The reduction ratios at the driven gears 11 and 15 calculated through the shaft system design are both 4, and are both used for single-turn angle measurement. The magnets 4 installed in the grooves on the upper end face of the eighth driven gear shaft 16 have a reduction ratio of 64, which is used for turn measurement. This design method realizes multi-turn absolute mechanical position measurement, and at the same time has a two-redundant structure and magnetic circuit design, which improves the reliability of the angle position measurement device. At the same time, the reduction ratios of the three magnets are 4:4:64, which are all multiples of 2. This avoids the complex floating-point operations of the system and directly performs binary shift operations, thereby improving the MCU data update speed and transmission speed.

[0043] The tail end of the split main shaft 3 is inserted into the motor shaft and fastened from the top with screws. The positioning is achieved by connecting with the motor shaft and the main shaft 3 is concentrically arranged with the central through hole of the base 1. The diameter of the central through hole of the base 1 is larger than the shaft diameter of the split main shaft 3. The upper end surface of the main shaft is flush with the upper end surface of the support plate 5.

[0044] All driven gear shafts are circumferentially positioned through the through holes on the circumference of the base 1, and axially positioned by relying on the overlap of the end face of the second boss on the base 1 with the end face of its own shaft shoulder. However, positioning is only performed on one end. Due to friction and installation accuracy issues, the gear shaft is prone to angular deflection and axial movement during rotation.

[0045] The support plate 5 is mounted on the first boss of the base, and the lower end surface of the support plate 5 coincides with the upper end surface of the boss. The support plate 5 is screwed through the screw hole on the first boss, and the pin hole on the boss coincides with the center of the hole at the corresponding position of the support plate. At the same time, through holes are arranged at the positions corresponding to the axis of the gear shaft of the support plate 5, and the axial fixation is achieved by coinciding the boss of the lower end surface with the upper end shoulder of the gear shaft, so that the other degrees of freedom of the gear except the rotation around the axis can be limited, and the axial movement and angular swing of the gear shaft are solved.

[0046] The circuit board 6 is positioned through the screw holes on the housing 2 and fixed on the upper surface of the support plate 5. There are three magnetic induction chips at the corresponding positions of the circuit board 6 and the magnetic steel 4 for recording the changing magnetic field signals, and transmitting the collected signals to the signal processing module on the circuit board 6, integrating them into actual coding values, and then processing and driving the actual coding values ​​through the output module to output the actual angle information of the motor rotation. The circuit design on the circuit board must adapt to the structural design of the gear reducer. The positions of the magnetic induction chips on the circuit board correspond to the positions of the three magnetic steels one by one, with high coaxiality, enhanced magnetic induction intensity, and conducive to the orthogonal solution of the induced magnetic field inside the magnetic induction core.

[0047] The present invention has the following beneficial effects:

[0048] (1) The circumferential rotational freedom of the gear shaft is limited by the positioning hole of the base and the corresponding axial hole of the support plate, so that the gear shaft can only rotate around the axial hole. At the same time, the boss at the axial hole on the bottom surface of the support plate limits the axial movement of the gear shaft, so that the gear shaft will not be separated from the positioning hole of the base due to impact, making the encoder impact-resistant and having high transmission accuracy.

[0049] (2) Compared with the photoelectric absolute encoder which has more requirements on the optical environment, the present invention has a reasonable structure and is simple and compact.

[0050] (3) In order to improve the impact resistance of the encoder, many inventions directly use high-strength impact-resistant materials, which greatly increases the cost, while adding a support plate has a lower cost requirement.

[0051] (4) The circuit board is positioned in the circumferential direction by embedding two pins fixed on the upper support plate into the holes of the circuit board. In this way, the circuit board can be positioned with high precision. Therefore, the position accuracy of the magnetic sensitive element on the circuit board can be improved, and the detection accuracy can be improved.

[0052] The above-described embodiments are only preferred specific implementations of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A split multi-turn magnetoelectric absolute position measuring device, characterized in that: It includes a base, a housing, a main shaft, a magnetic steel, a support plate, a gear reducer and a circuit board; The base is a two-layer boss structure with a through hole in the center, and multiple gear reducer mounting holes, positioning holes, and threaded holes are provided between the through hole and the edge; The outer shell is a barrel-shaped structure with an opening at the bottom, and the opening end is fixedly connected to the base; The main shaft of the main rotating shaft passes through the through hole of the base, and the tail end is inserted into the motor shaft and fastened; the gear of the main rotating shaft is meshed with the gear reducer to form a split structure; The support plate is mounted on the first-stage boss of the base, and the lower end surface coincides with the upper end surface of the first-stage boss; a plurality of positioning holes are arranged on the support plate, which are the same in number, size and position as the mounting holes of the gear reducer on the base; The gear reducer comprises more than two driven gear shafts connected in sequence, and the two ends of each driven gear shaft are respectively placed in the corresponding positioning holes and gear reducer mounting holes on the support plate and the base; grooves are provided on the upper surfaces of two of the driven gear shafts, and a magnet is placed in each groove; The two magnets are used to measure the single-turn angle and number of turns of the driven gear shaft. The circuit board is fixed on the upper surface of the support plate and is equipped with a signal processing module and multiple magnetic induction chips; the number of magnetic induction chips is the same as the number of magnets, each magnetic induction chip records the magnetic field signal of a magnet, and the signal processing module processes the magnetic field signal and outputs the actual angle information of the motor rotation.

2. The split multi-turn magnetoelectric absolute position measuring device according to claim 1, characterized in that: The base is provided with a plurality of positioning holes, gear shaft mounting holes and threaded holes between the central through hole and the edge. Each positioning hole is used for guiding and positioning between the support plate, the base and the circuit board to improve the coaxiality between the gear reducer and the magnetic sensitive chip on the circuit board; each gear shaft mounting hole is used to connect each driven gear shaft on the gear reducer, and the end face of the gear mounting hole is higher than the bottom surface of the base; the threaded holes include upper threaded holes and lower threaded holes, the lower threaded holes are used for fastening the outer shell, and the upper threaded holes are used for fastening the support plate.

3. The split multi-turn magnetoelectric absolute position measuring device according to claim 1, characterized in that: The lower shoulder end face of each driven gear shaft coincides with the end face of the second-stage boss on the base to achieve axial positioning.

4. The split multi-turn magnetoelectric absolute position measuring device according to claim 1, characterized in that: The reduction ratio of the driven gear shaft on which the magnetic steel is placed is a multiple of 2.

5. The split multi-turn magnetoelectric absolute position measuring device according to claim 1, characterized in that: The central through hole of the base is arranged concentrically with the main axis of the main rotating shaft, and the diameter of the central through hole of the base is larger than the shaft diameter of the main shaft, and the upper end surface of the main shaft is flush with the upper end surface of the support plate.

6. The split multi-turn magnetoelectric absolute position measuring device according to claim 1, characterized in that: The lower edge of each positioning hole on the support plate is provided with a boss, and the boss coincides with the shaft shoulder at the upper end of the driven gear shaft to achieve axial fixation.

7. The split multi-turn magnetoelectric absolute position measuring device according to claim 1, characterized in that: Grooves are provided on the upper surfaces of the three driven gear shafts, and a magnet is placed in each groove; two of the driven gear shafts have the same structure, and the magnets placed therein are used to measure the single-turn rotation angle of the driven gear shafts, thereby realizing dual-redundancy measurement; the magnet on the third driven gear shaft is used to measure the number of turns of the driven gear shaft; The signal processing module on the circuit board averages the single-turn angle information sensed by the two magnetic induction chips, and then integrates it with the number of turns into an actual code value. After converting the actual code value, the actual angle information of the motor rotation is obtained.

8. The split multi-turn magnetoelectric absolute position measuring device according to claim 1, characterized in that: Each driven gear shaft is provided with two gears distributed in upper and lower layers.

9. The split multi-turn magnetoelectric absolute position measuring device according to claim 1, characterized in that: The magnetic induction chips on the circuit board correspond to the positions of the magnetic steels one by one and are placed coaxially opposite to each other to enhance the magnetic induction strength.

10. The split multi-turn magnetoelectric absolute position measuring device according to claim 1, characterized in that: The gear reducer adopts the principle of small gear diameter at the front and large gear diameter at the back, that is, the transmission ratio is distributed gradually from the high speed stage to the low speed stage.

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