Hollow shaft miniaturized multi-turn encoder

Abstract

The application discloses a hollow shaft type miniaturized multi-turn encoder, which comprises a rotor module and a stator module; the stator module comprises a signal acquisition and processing assembly, a mechanical multi-turn gear assembly and an external interface and shell assembly; the rotor module is used for transmitting the motion information of a to-be-tested rotating shaft and a gear shaft engaged with the multi-turn gear; the signal acquisition and processing assembly is used for collecting voltage signals fed back by a stator coil and a magnetic sensing chip, and solving and processing the voltage signals into digital signals; the mechanical multi-turn gear assembly comprises a multi-stage gear transmission pair and a pin used for fixing the gear; the external interface and shell assembly comprises an interface cable, a shell and a light guide cover and the like structures, and the shell and the light guide cover are required to be installed through threads; the hollow shaft type miniaturized multi-turn encoder realizes signal acquisition and high-speed processing based on electromagnetic induction coupling and PCB coil technology, mechanical gear assembly research and transmission technology, strong magnetic environment coil noise reduction and synchronous solution technology, realizes real-time monitoring of the running state of the encoder through the light guide cover, has the advantages of compact structure, high precision, miniaturization and anti-adverse environment.

Description

Technical Field

[0001] This invention belongs to the field of angle sensor technology, and in particular to a hollow shaft miniaturized multi-turn encoder. Background Technology

[0002] A multi-turn encoder is a sensor used to detect angle and displacement and convert the detected actual mechanical displacement into digital signals. It can not only detect absolute angle and displacement within a 360° rotation range, but also record the number of rotations.

[0003] Traditional photoelectric multi-turn encoders have problems such as high cost, poor oil resistance, and poor impact resistance. Battery-powered multi-turn encoders have the risk of losing the number of turns due to battery depletion, circuit interference, or power failure. Wiegand multi-turn encoders have potential risks such as sensitivity to strong magnetic field interference and loss of turns when forced to run during power failure. None of these types of encoders have been widely used.

[0004] Currently, intelligent manufacturing is the main focus, and the requirements for encoders in various fields of the industry are becoming increasingly higher in terms of weight, size, and performance. This will drive greater growth potential for hollow shaft miniaturized multi-turn encoders, especially those with high precision, small size, low cost, and resistance to harsh environments. Summary of the Invention

[0005] The purpose of this invention is to provide a hollow shaft miniaturized multi-turn encoder to solve the defects of existing multi-turn encoders, such as poor environmental adaptability, easy loss of turns when power is off, high cost, and short service life.

[0006] The technical solution to achieve the purpose of this invention is as follows: a hollow shaft miniaturized multi-turn encoder, comprising a rotor module and a stator module; the rotor module includes a rotor housing and a rotor coil for transmitting motion information of the shaft under test; a gear shaft for meshing with a mechanical multi-turn gear is machined on the rotor housing; the stator module includes a signal acquisition and processing component, a mechanical multi-turn gear assembly, and an external interface and housing assembly; the signal acquisition and processing component includes a stator coil and a calculation circuit board for receiving voltage signals fed back from the rotor coil and the magnetic sensing chip; the calculation circuit board includes various passive components and various active chips, as well as a calculation, combination, and error correction module for synchronizing angle and number of turns, and calculates and processes the voltage signals fed back from the stator coil and the magnetic sensing chip into digital signals; the mechanical multi-turn gear assembly includes multiple gears and pins for fixing the gears, as well as magnets; the external interface and housing assembly includes an interface cable and a housing;

[0007] The rotor coil is fixed to the rotor housing;

[0008] The calculation circuit board is soldered onto the stator coil, and the various active chips include a microcontroller and the magnetic sensing chip;

[0009] The multiple gears are assembled into the inner cavity of the outer casing with pins that fix the gears. The multiple gears include a first-stage gear, several double-gears, several magnetic gears, and several small gears. Each magnetic gear has a groove containing a magnet. The gear shaft of the rotor housing meshes with the first-stage gear, meaning the gear shaft and the large gear of the first-stage gear have the same module. The gear shaft drives the first-stage gear to rotate, which in turn drives several double-gears, several magnetic gears, and several small gears to move synchronously. This, in turn, drives several magnets to move synchronously, causing relative rotation between several magnetic sensing chips on the calculation circuit board. Each magnetic sensing chip generates a different voltage signal and sends it to the microcontroller. The microcontroller reassembles the data and, based on the calculation, combination, and error correction modules, obtains the final angle data after integrating the single-turn absolute angle and the number of turns for multiple turns. This data is then sent out through the communication serial port of the interface cable. The voltage signal generated by each magnetic sensing chip represents the mechanical angle information of its corresponding magnet.

[0010] One end of the interface cable is soldered to the calculation circuit board, and the other end provides power and communication interfaces to the outside; the outer shell is provided with an observation hole for adjusting the concentric installation of the stator and rotor, and an interface cable outlet hole.

[0011] Furthermore, the rotor coil and the stator coil are respectively provided with coarse and fine channel combinations with mutually prime periods, and the number of coarse and fine channel combinations on the rotor coil and the stator coil is the same; the stator coil also includes an excitation coil.

[0012] Furthermore, soft magnetic material is bonded to the back of both the rotor coil and the stator coil; marking lines are provided on the stator coil to ensure the concentricity and absolute position of the circuit board soldering.

[0013] Furthermore, the installation spacing between the rotor coil and the stator coil is controlled within the range of 0.5mm ± 0.1mm.

[0014] Furthermore, each of the several small gears is a single gear, and the remaining gears each contain two gears, a large gear and a small gear, with different modules for the large and small gears; the several small gears are used to adjust the center distance of all gears.

[0015] Furthermore, the ratio of the number of teeth and the module of the plurality of gears must satisfy the following condition: for every one revolution of the gear shaft of the rotor housing, the plurality of magnetic gears each rotate by 1 / 2. n Circle, 1 / 2 2n Circle, 1 / 2 3n Circle, ..., 1 / 2 mn In the revolution, m represents the number of magnetic gears, and n represents the number of bits of resolution that each magnetic gear can achieve.

[0016] Furthermore, the outer ring of the stator coil has multiple grooves distributed non-uniformly along the circumference, and the inner ring of the outer shell has multiple bosses distributed non-uniformly along the circumference, with the multiple grooves cooperating with the multiple bosses respectively.

[0017] Furthermore, the pin has a T-shaped structure, and the T-shaped structure combined with the interference fit method realizes the bidirectional limiting of the gear.

[0018] Furthermore, the installation spacing of the plurality of magnets and the plurality of magnetic sensing chips is controlled within the range of 1.5mm ± 0.5mm.

[0019] Furthermore, the external interface and housing assembly also include a light guide cover, and the calculation circuit board is also provided with a light-emitting element; the microcontroller controls the light-emitting element to display the encoder's working status in real time through colored light; the light guide cover is used to transmit the colored light emitted by the light-emitting element in real time.

[0020] Compared with the prior art, the significant advantages of this invention are:

[0021] (1) Based on electromagnetic induction coupling and PCB coil technology, it has a compact structure and strong resistance to harsh environments; based on strong magnetic environment coil noise reduction and synchronous calculation technology, it realizes accurate signal acquisition and high-speed and efficient processing.

[0022] (2) Based on the internal mechanical gear set structure, the structure is simple and cost-effective; the number of revolutions is directly recorded through physical transmission, without relying on battery power or electronic counting register, avoiding the risk of loss of revolutions due to battery depletion, circuit interference or power failure.

[0023] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0024] Figure 1 A triaxial view of a hollow shaft miniaturized multi-turn encoder in one embodiment.

[0025] Figure 2 This is a partial enlarged view of four fixing methods for the rotor coil of a hollow shaft miniaturized multi-turn encoder in one embodiment.

[0026] Figure 3 In one embodiment, a hollow shaft miniaturized multi-turn encoder mechanical multi-turn gear assembly is provided.

[0027] Figure 4 This is a schematic diagram of the installation of a hollow shaft miniaturized multi-turn encoder gear assembly in one embodiment.

[0028] Figure 5 In one embodiment Figure 1 An isometric drawing of a local structure that implements multi-cycle counting functionality.

[0029] Figure 6 This is a cross-sectional view of a hollow shaft miniaturized multi-turn encoder structure in one embodiment.

[0030] Figure 7 This is a schematic diagram of the working principle of a hollow shaft miniaturized multi-turn encoder in one embodiment.

[0031] In the diagram, 1—rotor housing, 2—rotor coil, 3—outer shell, 4—stator coil, 5—solution circuit board, 6—first magnet, 7—second magnet, 8—third magnet, 9—pin, 10—first pin, 11—second pin, 12—third pin, 13—fourth pin, 14—fifth pin, 15—sixth pin, 16—seventh pin, 17—eighth pin, 18—first stage gear, 19—first double gear, 20—first magnet gear, 21—first pinion. 22—Second double gear, 23—Second magnetic gear, 24—Second pinion, 25—Third double gear, 26—Third magnetic gear, 27—Set screw, 28—Socket head cap screw, 29—Soft magnetic material, 30—Adhesive, 31—Socket head cap countersunk screw, 32—Deep groove ball bearing, 33—First magnetic chip, 34—Second magnetic chip, 35—Third magnetic chip, 36—Marker line, 37—Light guide cover, 38—Light-emitting element, 39—Interface cable. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0033] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0034] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0035] In one embodiment, combined Figures 1 to 6 A hollow shaft miniaturized multi-turn encoder is provided, including a rotor module and a stator module. The rotor module includes a rotor housing 1 and a rotor coil 2 for transmitting motion information of the shaft under test. A gear shaft that meshes with a mechanical multi-turn gear is machined on the rotor housing 1. The stator module includes a signal acquisition and processing component, a mechanical multi-turn gear assembly, and an external interface and housing assembly. The signal acquisition and processing component includes a stator coil 4 and a calculation circuit board 5 for receiving voltage signals fed back from the rotor coil 2 and the magnetic sensing chip. The calculation circuit board 5 includes a printed circuit board, passive components such as resistors, capacitors, and inductors, and various active chips, as well as a calculation, combination, and error correction module for synchronizing angle and number of turns, and calculates and processes the voltage signals fed back from the stator coil and the magnetic sensing chip into digital signals. The mechanical multi-turn gear assembly includes multiple gears and pins for fixing the gears, as well as magnets. The external interface and housing assembly includes an interface cable 39 and a housing 3.

[0036] The rotor coil 2 is fixed to the rotor housing 1, and the fixing method includes, but is not limited to, four types: boss fixing, adhesive fixing, screw fixing, and interference fixing. Preferably, the rotor housing 1 is radially limited to the shaft under test by a set screw 27, and axially limited to the shaft under test by a hexagon socket head cap screw 28.

[0037] The calculation circuit board 5 is soldered onto the stator coil 4, and the various active chips include microcontrollers, magnetic induction chips, analog switches, operational amplifiers, and transceivers.

[0038] The multiple gears are assembled into the inner cavity of the outer casing with pins that fix the gears. The multiple gears include a first-stage gear, several double-gears, several magnetic gears, and several small gears. Each magnetic gear has a groove containing a magnet. The gear shaft of the rotor housing meshes with the first-stage gear, meaning the gear shaft and the large gear of the first-stage gear have the same module. The gear shaft drives the first-stage gear to rotate, which in turn drives several double-gears, several magnetic gears, and several small gears to move synchronously. This, in turn, drives several magnets to move synchronously, causing relative rotation between several magnetic sensing chips on the calculation circuit board. Each magnetic sensing chip generates a different voltage signal and sends it to the microcontroller. The microcontroller reassembles the data and, based on the calculation, combination, and error correction modules, obtains the final angle data after integrating the single-turn absolute angle and the number of turns for multiple turns. This data is then sent out through the communication serial port of the interface cable. The voltage signal generated by each magnetic sensing chip represents the mechanical angle information of its corresponding magnet.

[0039] One end of the interface cable 39 is soldered to the calculation circuit board 5, and the other end provides power and communication interfaces to the outside; the outer shell is provided with an observation hole for adjusting the concentric installation of the stator and rotor, and an interface cable outlet hole.

[0040] Preferably, in some embodiments, the rotor coil 2 and the stator coil 4 are respectively provided with coarse and fine channel combinations with mutually prime periods, and the number of coarse and fine channel combinations on the rotor coil 2 and the stator coil 4 is the same; the stator coil also includes an excitation coil.

[0041] Preferably, in some embodiments, the back of both the rotor coil 2 and the stator coil 4 is bonded with soft magnetic material to enhance the intensity of the coarse and fine channel induction signals.

[0042] Preferably, in some embodiments, the stator coil 4 is provided with marking lines 36 to ensure the concentricity and absolute position of the solution circuit board 5 during soldering.

[0043] Preferably, in some embodiments, the installation spacing between the rotor coil 2 and the stator coil 4 is controlled within the range of 0.5mm ± 0.1mm. Here, the installation spacing between the rotor coil 2 and the stator coil 4 can be controlled by designing the assembly height from the mounting end face of the shaft to be tested to the mounting flange face.

[0044] Preferably, in some embodiments, the outer ring of the stator coil 4 has multiple (at least three) grooves distributed non-uniformly along the circumference, and the inner ring of the outer shell 3 has multiple (at least three) bosses distributed non-uniformly along the circumference. The multiple grooves cooperate with the multiple bosses respectively to ensure the uniqueness of the installation angle of the magnetic chip on the calculation circuit board 5.

[0045] Preferably, in some embodiments, each of the plurality of pinions is a single gear, and the remaining gears each include two gears, a large gear and a small gear, and the large gear and the small gear have different modules; the plurality of pinions are used to adjust the center distance of all gears.

[0046] Preferably, in some embodiments, the ratio of the number of teeth and the module of the plurality of gears needs to satisfy the following: for every 1 revolution of the gear shaft of the rotor housing, the plurality of magnetic gears each rotate 1 / 2. n Circle, 1 / 2 2n Circle, 1 / 2 3n Circle, ..., 1 / 2 mn In the revolution, m represents the number of magnetic gears, and n represents the number of bits of resolution that each magnetic gear can achieve.

[0047] Preferably, in some embodiments, the plurality of gears includes a first-stage gear 18, a first double gear 19, a second double gear 22, a third double gear 25, a first magnetic gear 20, a second magnetic gear 23, a third magnetic gear 26, a first pinion 21, and a second pinion 24. A first magnet 6, a second magnet 7, and a third magnet 8 are respectively disposed in the grooves of the first magnetic gear 20, the second magnetic gear 23, and the third magnetic gear 26. The gear shaft of the rotor housing meshes with the first-stage gear 18, meaning the gear shaft has the same module as the large gear of the first-stage gear 18. The gear shaft drives the first-stage gear 18 to rotate, thereby driving the first double gear 19, the first magnetic gear 20, the first pinion 21, the second double gear 22, the second magnetic gear 23, the first pinion 21, and the third double gear 25. Wheel 25 and third magnet gear 26 move synchronously, thereby driving first magnet 6, second magnet 7, and third magnet 8 to move synchronously, relative to the first magnetic sensing chip 33, second magnetic sensing chip 34, and third magnetic sensing chip 35 on the calculation circuit board 5. Different voltage signals are generated on the first magnetic sensing chip 33, second magnetic sensing chip 34, and third magnetic sensing chip 35 and sent to the microcontroller. The microcontroller reassembles the data and, based on the calculation, combination, and error correction modules, obtains the final angle data after integrating the single-turn absolute angle and the number of turns of multiple turns, and sends it out through the communication serial port of the interface cable. The different voltage signals generated on the first magnetic sensing chip 33, second magnetic sensing chip 34, and third magnetic sensing chip 35 represent the mechanical angle information of the first magnet 6, second magnet 7, and third magnet 8, respectively.

[0048] Preferably, the pins for fixing the gear include a pin shaft 9, a first pin 10, a second pin 11, a third pin 12, a fourth pin 13, a fifth pin 14, a sixth pin 15, a seventh pin 16, and an eighth pin 17; the pin shaft 9 passes through the deep groove ball bearing 32 and is placed in the bearing chamber of the first stage gear 18 before being press-fitted into the inner cavity of the housing 3; the first pin 10 passes through the first double gear 19 and is press-fitted into the inner cavity of the housing 3; the second pin 11 passes through the first magnetic gear 20 and is press-fitted into the inner cavity of the housing 3. The third pin 12 passes through the first pinion 21 and is interference-fitted into the inner cavity of the outer casing 3; the fourth pin 13 passes through the second double gear 22 and is interference-fitted into the inner cavity of the outer casing 3; the fifth pin 14 passes through the second magnetic gear 23 and is interference-fitted into the inner cavity of the outer casing 3; the sixth pin 15 passes through the second pinion 24 and is interference-fitted into the inner cavity of the outer casing 3; the seventh pin 16 passes through the third double gear 25 and is interference-fitted into the inner cavity of the outer casing 3; the eighth pin 17 passes through the third magnetic gear 26 and is interference-fitted into the inner cavity of the outer casing 3.

[0049] Preferably, the first pinion 21 and the second pinion 24 are used to adjust the center distance of the gears to avoid interference during the assembly of the multiple gears.

[0050] Preferably, the axes of the first magnetic gear 20, the first magnet 6, the second pin 11, and the first magnetic chip 33 are located on the same straight line; the axes of the second magnetic gear 23, the second magnet 7, the fifth pin 14, and the second magnetic chip 34 are located on the same straight line; and the axes of the third magnetic gear 26, the third magnet 8, the eighth pin 17, and the third magnetic chip 35 are located on the same straight line.

[0051] Preferably, the installation spacing of the first magnet 6 to the third magnet 8 and the first magnetic sensing chip 33 to the third magnetic sensing chip 35 is controlled within the range of 1.5mm ± 0.5mm.

[0052] Preferably, all the pins are T-shaped structures, and the T-shaped structure and the interference fit method realize the bidirectional limiting of the gear.

[0053] Preferably, in some embodiments, the external interface and housing assembly further includes a light guide cover 37, and the calculation circuit board 5 is also provided with a light-emitting element 38; the microcontroller controls the light-emitting element 38 to display the encoder's working status in real time through colored light; the light guide cover 37 is used to transmit the colored light emitted by the light-emitting element 38 in real time.

[0054] Preferably, the axes of the light-emitting element 38 and the light guide cover 37 are on the same straight line.

[0055] Preferably, the outer shell 3 is also provided with a threaded hole for a matching light guide cover 37, which is installed in the inner cavity of the outer shell 3 by means of threads.

[0056] Preferably, the gap between the light guide cover 37 and the outer shell 3 is filled with silicone to resist vibration, impact and other working conditions.

[0057] The following describes in detail, with reference to the accompanying drawings, the production, assembly, and measurement processes of the present invention:

[0058] like Figures 1-6 As shown, the hollow shaft type miniaturized multi-turn encoder proposed in this invention is particularly suitable for angle and displacement measurement in environments with high size requirements and harsh conditions. Its primary production process is described as follows:

[0059] Rotor Module: After the back of the rotor coil 2 is bonded with soft magnetic material 29, it is fixed to the rotor housing 1. This includes, but is not limited to, four methods: boss fixing, adhesive fixing, screw fixing, and interference fit fixing. Firstly, boss fixing: three (or more) grooves are evenly distributed on the inner and outer rings of the rotor coil 2, and three (or more) bosses are evenly distributed on the inner and outer rings of the rotor housing 1. The grooves of the rotor coil 2 correspond one-to-one with the bosses of the rotor housing 1. Secondly, adhesive fixing: a concave groove is machined on the end face of the rotor housing 1 where the rotor coil 2 is installed. Before installation, adhesive 30 is evenly applied along the circumference to the center of the concave groove. The overflow grooves on both sides of the groove prevent uneven bonding due to excessive adhesive. Adhesive 30 is also applied along the circumference of the inner ring of the rotor coil 2 to secure it. The sub-coil 2 is bonded and fixed to the rotor housing 1; thirdly, it is fixed with screws. The rotor coil 2 is machined with two locating pin holes and three (or more) countersunk screw holes. During installation, the locating pin shaft is first used to pre-fix it to the rotor housing 1 through the locating pin holes of the rotor coil 2, and then the three (or more) internal hexagon countersunk screws 31 are passed through the countersunk screw holes of the rotor coil 2 to lock it to the rotor housing 1; fourthly, it is fixed with interference fit. The rotor coil 2 has four (or more) through holes evenly distributed on the inner ring to release the stress generated by the interference fit. The inner ring of the rotor coil 2 is interference fitted with the outer ring of the rotor housing 1, and the interference fit is controlled within 0.02mm ± 0.01mm; the rotor coil 2 of this hollow shaft miniaturized multi-turn encoder adopts the boss fixing method.

[0060] Signal acquisition and processing components: Various active chips on the calculation circuit board 5, including microcontrollers, magnetic induction chips, analog switches, operational amplifiers, and transceivers, as well as various passive components, including resistors, capacitors, and inductors, are manufactured and mounted in one step via SMT. After the components are mounted, the program is burned. Soft magnetic material 29 is bonded to the back of the stator coil 4. The calculation circuit board 5, after mounting, is fixed to the stator coil 4 by soldering. The marking line 36 on the stator coil 4 ensures the concentricity and absolute position of the calculation circuit board 5 during soldering. After soldering, adhesive 30 is filled into the gap between the stator coil 4 and the calculation circuit board 5.

[0061] Mechanical multi-turn gear assembly: The third pin 12 and the sixth pin 15 pass through the first pinion 21 and the second pinion 24 respectively and are interference-fitted into the inner cavity of the housing 3; the fourth pin 13 and the seventh pin 16 pass through the second double gear 22 and the third double gear 25 respectively and are interference-fitted into the inner cavity of the housing 3; the second pin 11, the fifth pin 14, and the eighth pin 17 pass through the first magnetic gear 20, the second magnetic gear 23, and the third magnetic gear 26 respectively and are interference-fitted into the inner cavity of the housing 3; before the pins are assembled, adhesive 30 must be applied to the pin mounting through holes of the housing 3 to achieve the dual effect of interference-fitting and adhesive fixing after assembly; the first magnet 6, the second magnet 7, and the third magnet 8 are installed in the grooves of the first magnetic gear 20, the second magnetic gear 23, and the third magnetic gear 26 respectively using adhesive 30. Before bonding, a layer of release paper must be placed in the grooves to prevent adhesive 30 from overflowing into the rotation gap between the pins and the gears, causing rotation jamming or tooth breakage.

[0062] External Interface and Housing Assembly: The light guide cover 37 is threaded into the inner cavity of the housing 3, and silicone is filled in the gap between the light guide cover 37 and the housing 3 to resist vibration, impact and other working conditions; one end of the interface cable 39 is soldered to the calculation circuit board 5, and the other end passes through the interface cable 39 outlet hole of the housing 3 to provide power interface and communication interface to the outside; three (or more) grooves are non-uniformly distributed along the circumference of the outer ring of the stator coil 4 and are installed on three (or more) bosses non-uniformly distributed along the circumference of the inner ring of the housing 3 to ensure the uniqueness of the installation angle of the magnetic chip on the calculation circuit board 5; by designing the assembly height from the end face of the boss of the inner ring of the housing 3 to the magnetic gear, the installation spacing between the first magnetic chip and the third magnetic chip, and between the first magnet and the third magnet is controlled within the range of 1.5mm ± 0.5mm.

[0063] This completes one production cycle of the hollow shaft miniaturized multi-turn encoder.

[0064] The hollow shaft miniaturized multi-turn encoder, after completing the production process, firstly, after radially limiting the rotor module with the shaft to be tested using set screws 27, the stator module is fitted onto the rotor module. The concentricity of the rotor module and stator module is adjusted by using a special installation tool to adjust the inner hole of the gear shaft of the rotor housing 1 and the concentricity observation hole of the outer shell 3. Secondly, the stator module is fixed to the mounting flange surface using four cross-slot pan head screws, and then the special installation tool is removed. Finally, the hexagon socket head cap screws 28 are used to axially limit the shaft to be tested by passing through the inner hole of the gear shaft of the rotor housing 1. The assembly height from the mounting end face of the shaft to be tested to the mounting flange surface is designed to ensure that the installation spacing II of the rotor coil 2 and the stator coil 4 is controlled within the range of 0.5mm ± 0.1mm.

[0065] This completes one assembly process for the hollow shaft miniaturized multi-turn encoder.

[0066] Power on the encoder via the positive and negative wires of interface cable 39. After the communication serial port of interface cable 39 enters the debugging mode, align the single-turn absolute angle zero point and the multi-turn count zero point and then clear them to zero.

[0067] The stator module is fixed to the mounting flange surface, the stator coil 4 and the calculation circuit board 5 are fixed in position, and the rotor module is fixed to the shaft under test. The rotation information of the device under test is transmitted to the rotor housing 1 through the shaft. Because the gear shaft of the rotor housing 1 meshes with the large gear of the first stage gear 18, the gear shaft drives the first stage gear 18 of the mechanical multi-turn gear assembly to rotate, which in turn drives the first double gear 19, the first magnetic gear 20, the first pinion 21, the second double gear 22, the second magnetic gear 23, the first pinion 21, the third double gear 25, and the third magnetic gear 26 to move synchronously. Through a special tooth number and module ratio, the first magnetic gear 20 rotates 1 / 2 for every 1 revolution of the gear shaft of the rotor housing 1. n The second magnet gear 23 rotates 1 / 2. n / 2 n =1 / 2 2n The third magnet gear 26 rotates 1 / 2. n / 2 n / 2 n =1 / 2 3n This causes the first magnet 6, the second magnet 7, and the third magnet 8, which are respectively installed in the grooves of the first magnet gear 20, the second magnet gear 23, and the third magnet gear 26, to move synchronously and follow each other. They also rotate relative to the first magnetic sensing chip 33, the second magnetic sensing chip 34, and the third magnetic sensing chip 35 on the calculation circuit board 5, and different voltage signals are generated on the first magnetic sensing chip to the third magnetic sensing chip.

[0068] Combination Figure 7 When a high-frequency alternating signal is connected to the excitation coil of stator coil 4, the excitation coil generates an alternating magnetic field. When rotor coil 2 cuts magnetic field lines in the alternating magnetic field, an induced current is generated within rotor coil 2, i.e., an induced current signal. The induced current signal of rotor coil 2 also generates an alternating magnetic field, and stator coil 4, after sensing the magnetic field generated by rotor coil 2, also induces a voltage signal. As the rotor module below the encoder stator module rotates to different positions, the amplitudes of the electromotive forces induced in the sine and cosine coils of the coarse and fine channels of stator coil 4 are different. The amplitude of the induced electromotive force in the sine coil is a sine function of the rotor module's angular position, and the amplitude of the induced electromotive force in the cosine coil is a cosine function of the rotor's angular position. Due to the encoder's unique coil arrangement, the voltage signals in the sine and cosine coils within the coarse and fine channels of stator coil 4 are both functions of the rotor's angular position. The combination of coarse and fine code tracks with mutually prime periods can determine the absolute position of the rotor module, thereby confirming the absolute position of the shaft under test.

[0069] To calculate the absolute angle of a single encoder turn, the sine and cosine signals of each channel need to be demodulated, the carrier signal removed, and then the signal amplified. The signal is then sampled at high speed by an AD converter and sent to the microcontroller for position calculation. To calculate the number of multiple position turns, the first magnetic sensing chip 33, the second magnetic sensing chip 34, and the third magnetic sensing chip 35 convert the mechanical angle information of the rotation of the first magnet 6, the second magnet 7, and the third magnet 8 into voltage signals, respectively, and send them to the microcontroller for data reassembly. Based on a unique software algorithm for calculation, combination, and error correction, the final angle data after integrating the absolute angle of a single turn and the number of multiple position turns is obtained and sent out through the communication serial port of the interface cable 39. Additionally, the microcontroller controls the light-emitting element 38 on the calculation circuit board 5 to transmit and display the encoder's working status in real time via the light guide cover 37. The default setting is a flashing green light for normal operation and a flashing red light for abnormal operation (this default setting is not limited to this one).

[0070] This completes one measurement process for the hollow shaft miniaturized multi-turn encoder.

[0071] In summary, the hollow shaft miniaturized multi-turn encoder of this invention, based on electromagnetic induction coupling and PCB coil technology, mechanical gear set research and transmission technology, and strong magnetic environment coil noise reduction and synchronous calculation technology, achieves accurate signal acquisition and efficient high-speed processing. The product has a compact shape, high cost performance, and is suitable for harsh environmental conditions. It is an ideal solution for integration into servo motors, stepper motors, and various robot joints and robotic arms.

[0072] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention without departing from its spirit and scope should be included within the protection scope of the present invention.

Claims

1. A hollow shaft type miniaturized multi-turn encoder, characterized in that, The system includes a rotor module and a stator module. The rotor module includes a rotor housing and rotor coils for transmitting motion information of the shaft under test. A gear shaft that meshes with a multi-turn mechanical gear is machined on the rotor housing. The stator module includes a signal acquisition and processing component, a multi-turn mechanical gear assembly, and an external interface and housing assembly. The signal acquisition and processing component includes stator coils and a calculation circuit board for receiving voltage signals from the rotor coils and the magnetic induction chip. The calculation circuit board includes various passive components and active chips, as well as a module for calculating, combining, and correcting errors to synchronize angle and number of turns, and processes the voltage signals from the stator coils and the magnetic induction chip into digital signals. The multi-turn mechanical gear assembly includes multiple gears, pins for fixing the gears, and magnets. The external interface and housing assembly includes an interface cable and a housing. The rotor coil is fixed to the rotor housing; The calculation circuit board is soldered onto the stator coil, and the various active chips include a microcontroller and the magnetic sensing chip; The multiple gears are assembled into the inner cavity of the outer casing with pins that fix the gears. The multiple gears include a first-stage gear, several double-gears, several magnetic gears, and several small gears. Each magnetic gear has a groove containing a magnet. The gear shaft of the rotor housing meshes with the first-stage gear, meaning the gear shaft and the large gear of the first-stage gear have the same module. The gear shaft drives the first-stage gear to rotate, which in turn drives several double-gears, several magnetic gears, and several small gears to move synchronously. This, in turn, drives several magnets to move synchronously, causing relative rotation between several magnetic sensing chips on the calculation circuit board. Each magnetic sensing chip generates a different voltage signal and sends it to the microcontroller. The microcontroller reassembles the data and, based on the calculation, combination, and error correction modules, obtains the final angle data after integrating the single-turn absolute angle and the number of turns for multiple turns. This data is then sent out through the communication serial port of the interface cable. The voltage signal generated by each magnetic sensing chip represents the mechanical angle information of its corresponding magnet. One end of the interface cable is soldered to the calculation circuit board, and the other end provides power and communication interfaces to the outside; the outer shell is provided with an observation hole for adjusting the concentric installation of the stator and rotor, and an interface cable outlet hole.

2. The hollow shaft miniaturized multi-turn encoder according to claim 1, characterized in that, The rotor coil and stator coil are respectively provided with coarse and fine channel combinations with mutually prime periods, and the number of coarse and fine channel combinations on the rotor coil and stator coil is the same; the stator coil also includes an excitation coil.

3. The hollow shaft miniaturized multi-turn encoder according to claim 1, characterized in that, The back of both the rotor coil and the stator coil is bonded with soft magnetic material; the stator coil is marked with marking lines to ensure the concentricity and absolute position of the circuit board soldering.

4. The hollow shaft miniaturized multi-turn encoder according to claim 1, characterized in that, The installation spacing between the rotor coil and the stator coil is controlled within the range of 0.5mm ± 0.1mm.

5. The hollow shaft type miniaturized multi-turn encoder according to claim 1, characterized in that, Each of the several pinions is a single gear, and the remaining gears each contain two gears, a large one and a small one, with different modules for the large and small gears; the several pinions are used to adjust the center distance of all gears.

6. The hollow shaft miniaturized multi-turn encoder according to claim 1, characterized in that, The tooth count and module ratio of the multiple gears must satisfy the following condition: for every one revolution of the gear shaft in the rotor housing, each of the several magnetic gears rotates by 1 / 2. n Circle, 1 / 2 2n Circle, 1 / 2 3n Circle, ..., 1 / 2 mn In the revolution, m represents the number of magnetic gears, and n represents the number of bits of resolution that each magnetic gear can achieve.

7. The hollow shaft miniaturized multi-turn encoder according to claim 1, characterized in that, The outer ring of the stator coil has multiple grooves distributed non-uniformly along the circumference, and the inner ring of the outer shell has multiple bosses distributed non-uniformly along the circumference. The multiple grooves are respectively matched with the multiple bosses.

8. The hollow shaft miniaturized multi-turn encoder according to claim 1, characterized in that, The pin has a T-shaped structure, and the T-shaped structure and the interference fit method realize the bidirectional positioning of the gear.

9. The hollow shaft miniaturized multi-turn encoder according to claim 1, characterized in that, The installation spacing of the plurality of magnets and the plurality of magnetic sensing chips is controlled within the range of 1.5mm ± 0.5mm.

10. The hollow shaft miniaturized multi-turn encoder according to claim 1, characterized in that, The external interface and housing assembly also include a light guide cover, and the calculation circuit board is also provided with a light-emitting element; the microcontroller controls the light-emitting element to display the encoder's working status in real time through colored light; the light guide cover is used to transmit the colored light emitted by the light-emitting element in real time.

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