Magnetostrictive displacement sensor of large-scale road maintenance machinery

Abstract

The invention discloses a magnetostrictive displacement sensor of large-scale road maintenance machinery, and relates to the technical field of road maintenance machinery, the magnetostrictive displacement sensor is arranged on an oil cylinder of the large-scale road maintenance machinery, the magnetostrictive displacement sensor comprises a position magnetic ring and a sensor main body, the position magnetic ring is connected to a piston rod of the oil cylinder, and the sensor main body is fixedly arranged in the oil cylinder; the sensor main body comprises a main printed board, a waveguide wire and a detection assembly, the waveguide wire is connected to the detection assembly, and the detection assembly is connected to the main printed board; the waveguide wire and the detection assembly are fixedly arranged in a cylinder body of the oil cylinder, and the main printed board is electrically connected with a cable core wire; a piston rod of the oil cylinder is provided with an installation hole, and the waveguide wire penetrates through the position magnetic ring and is installed in the installation hole. The system has the advantages of good displacement sensing precision, strong anti-interference capability, long service life, good reliability and the like, and is suitable for pavement maintenance work of large-scale road maintenance machinery.

Description

Technical Field

[0001] This invention relates to the technical field of road maintenance machinery, and particularly to a magnetostrictive displacement sensor for large-scale road maintenance machinery. Background Technology

[0002] Large road maintenance machinery needs to travel and operate on the road being maintained at a set speed. During operation, the stroke of the mechanical grinding head is controlled by the hydraulic cylinders installed on the vehicle. Sensors are used to collect parameters of the cylinder stroke during operation, and the grinding head is controlled according to the parameters.

[0003] Large road maintenance machinery requires sensors to obtain piston stroke parameters of the hydraulic cylinders during operation, controlling the movement of the grinding head to keep it close to the railway for grinding. This necessitates high precision in the movement of the grinding head. Furthermore, the road maintenance process generates vibrations and produces a high-temperature, dusty environment.

[0004] The displacement sensors used in traditional large-scale road maintenance machinery have low accuracy, making it difficult to meet the precision requirements of grinding. These sensors are also susceptible to interference from the grinding environment, directly affecting their accuracy. Furthermore, because the sensors are externally mounted, they wear out quickly, have a short lifespan, and exhibit low reliability in high-temperature, dusty environments. Summary of the Invention

[0005] The purpose of this invention is to provide a magnetostrictive displacement sensor for large road maintenance machinery, which has the advantages of good displacement sensing accuracy, strong anti-interference ability, long life and high reliability, and is suitable for road maintenance work of large road maintenance machinery.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: This invention provides a magnetostrictive displacement sensor for large-scale road maintenance machinery. The magnetostrictive displacement sensor is disposed in the hydraulic cylinder of the large-scale road maintenance machinery. The magnetostrictive displacement sensor includes a position magnetic ring and a sensor body. The position magnetic ring is coaxially connected to the piston rod of the hydraulic cylinder, and the sensor body is fixedly disposed inside the hydraulic cylinder. The sensor body includes a main printed circuit board, a waveguide wire, and a detector assembly. The waveguide wire is connected to the detector assembly, and the detector assembly is connected to the main printed circuit board. The waveguide wire and the detector assembly are fixedly disposed in the cylinder body of the hydraulic cylinder. The main printed circuit board is electrically connected to a cable core wire for power supply and signal output, and the cable core wire passes through the cylinder body of the hydraulic cylinder. The waveguide wire is a long linear magnetostrictive material. The piston rod of the hydraulic cylinder has a mounting hole. The waveguide wire passes through the position magnetic ring and is installed in the mounting hole. The waveguide wire can move axially relative to the mounting hole. The main printed circuit board can send an excitation current signal to the waveguide wire. Under the action of the excitation current signal, the waveguide wire generates a torsional wave at the position magnetic ring. The detection component can output a detection signal to the main printed circuit board when the torsional wave is detected.

[0007] Furthermore, the main printed circuit board includes a microprocessor module and a power conversion module, an excitation module, a signal processing module, and an output conversion module connected to the microprocessor module. The power conversion module is used to input and convert power to the main printed circuit board. The excitation module is used to output an excitation current signal to the waveguide wire. The signal processing module is used to receive the detection signal emitted by the detector assembly and measure the time of receiving the detection signal. The microprocessor module calculates the distance between the position magnetic ring and the detector assembly based on the time difference between emitting the excitation current signal and receiving the detection signal and the speed at which the torsional wave propagates in the waveguide wire.

[0008] Furthermore, both the detector assembly and the main printed circuit board are disposed in the rodless chamber of the hydraulic cylinder at the end away from the piston rod.

[0009] Furthermore, the position magnetic ring is fixedly disposed at the end of the piston rod facing the rodless cavity, and the position magnetic ring, the mounting hole and the piston rod are coaxially arranged.

[0010] Furthermore, the waveguide wire is fitted with an outer sheath made of a rigid material, and the outer sheath is axially movable and inserted into the mounting hole.

[0011] Furthermore, the magnetostrictive displacement sensor also includes a housing and a cover. The housing is fixedly disposed within the cylinder of the hydraulic cylinder, and the cover is detachably connected to the housing. The detector assembly and the main printed circuit board are installed in the housing. The housing has a first through hole communicating with the inner cavity of the housing. The outer protective shell is fixedly fitted to the first through hole, and the waveguide wire passes through the first through hole and is inserted into the outer protective shell. The cover has a second through hole, and the cable core wire passes through the second through hole.

[0012] Furthermore, a protective sleeve is sealed inside the second through hole, and the protective sleeve is sealed outside the cable core wire; The housing is fitted with a first sealing ring, the outer circumference of which seals against the inner wall of the cylinder; the cover fits into the opening of the housing, and the outer circumference of the cover is fitted with a second sealing ring, the outer ring of which seals against the inner wall of the housing.

[0013] Furthermore, the detection assembly includes a detection printed circuit board and a detection coil. The detection printed circuit board is electrically connected to the main printed circuit board, and the detection coil is electrically connected to the detection printed circuit board. The detection coil can generate a voltage change when the waveguide wire at the detection coil generates a magnetic field change.

[0014] Furthermore, the axis of the detector coil is parallel to the axis of the waveguide wire, and the waveguide wire is disposed outside the detector coil.

[0015] Furthermore, a bias magnet is inserted inside the detector coil.

[0016] In summary, the present invention has the following beneficial effects: 1. The magnetostrictive displacement sensor of the present invention is installed in the hydraulic cylinder of a large track maintenance machine. The sensor body is fixedly installed in the hydraulic cylinder, and the position magnetic ring is fixedly connected to the piston rod. When the hydraulic cylinder extends and retracts to drive the grinding head to perform grinding operations, the position magnetic ring extends and retracts with the piston rod. Therefore, the displacement of the grinding head can be measured by measuring the displacement of the position magnetic ring relative to the sensor body. Specifically, the waveguide wire is axially movable and passes through the mounting hole of the piston rod. When the piston rod moves, the position magnetic ring can move relative to the waveguide wire. During measurement, the main printed circuit board outputs an excitation current signal to the waveguide wire, and the waveguide wire generates an Ampere ring magnetic field. At the position magnetic ring, the magnetic field of the waveguide wire and the magnetic field of the position magnetic ring are coupled. Due to the Widmann effect, a torsional wave is formed on the surface of the waveguide wire. When the torsional wave propagates along the waveguide wire to the detector assembly, the detector assembly detects the torsional wave and outputs a detection signal to the main printed circuit board. The main printed circuit board can calculate the location of the torsional wave based on the time difference between the excitation current signal and the detection signal and the propagation speed of the torsional wave, and thus know the displacement of the position magnetic ring and the piston rod.

[0017] This invention utilizes a magnetostrictive displacement sensor to detect the piston displacement of hydraulic cylinders in large track maintenance machinery. The magnetostrictive displacement sensor is housed within the cylinder, exhibiting good environmental adaptability and being less affected by high temperatures and dust during operation. This solution employs non-contact measurement; there is no direct contact between the position magnetic ring and the sensor body, minimizing wear during measurement and eliminating the need for sensor maintenance. The magnetostrictive displacement sensor operates based on an excitation current signal, requiring only the measurement of the time interval between the excitation current signal and the detection signal. This method is convenient, offers high measurement accuracy, and is unaffected by power interruptions and subsequent power restorations. It eliminates the need for zero-homing, signal amplification, and periodic recalibration. The position magnetic ring only requires physical fixation, eliminating the need for external circuitry and facilitating installation within the hydraulic cylinder.

[0018] 2. The main printed circuit board converts the external voltage input from the cable core wire into an internal voltage that can be used by the magnetostrictive displacement sensor through the power conversion module. The excitation module outputs an excitation current signal to the waveguide wire. After the torsional wave reaches the detector assembly, the detector assembly sends a detection signal, which is received by the signal processing module. The signal processing module detects the time of receiving the detection signal and sends it to the microprocessor module. The microprocessor module can calculate the position of the torsional wave based on the time difference between the time of the excitation current and the time of the detection signal, and thus know the displacement of the position magnetic ring and the cylinder piston rod.

[0019] 3. The detector assembly and the main printed circuit board are located in the rodless chamber of the hydraulic cylinder at the end away from the piston rod, so that the placement of the detector assembly and the main printed circuit board is less likely to interfere with the normal extension and retraction of the piston rod of the hydraulic cylinder, and reduces the probability of collision and wear of the detector assembly, the main printed circuit board and the piston rod.

[0020] 4. The position magnetic ring is fixedly installed at the end of the piston rod facing the rodless cavity, making the distance between the position magnetic ring and the sensor body short. When the piston rod extends out of the cylinder body, the waveguide wire is gradually pulled out of the mounting hole in the direction away from the piston rod. During this process, the position magnetic ring can remain sleeved on the outside of the waveguide wire, ensuring that the measurement of piston rod displacement can be carried out normally. The position magnetic ring, mounting hole and piston shaft are set coaxially, which facilitates the coaxial setting of the position magnetic ring and the waveguide wire and ensures the magnetostrictive effect of the waveguide wire.

[0021] 5. A rigid outer shell is installed around the waveguide wire to protect it and reduce friction and collision between the waveguide wire and the inner wall of the mounting hole when the piston rod extends or retracts. At the same time, the outer shell is inserted into the mounting hole and guides the waveguide wire when the piston rod extends or retracts, making the waveguide wire and the outer shell more stable when moving along the axial direction of the mounting hole.

[0022] 6. The detector assembly and main printed circuit board are installed between the housing and the cover. The housing and cover protect the detector assembly and main printed circuit board, reducing the impact of hydraulic oil on them and improving the IP protection capability of the magnetostrictive displacement sensor. The housing is connected to the outer sheath through a first through-hole, and the waveguide wire passes through the first through-hole and is then inserted into the outer sheath; the cable core wire exits from the second through-hole in the cover. This arrangement makes the overall structure of the magnetostrictive displacement sensor compact, provides good protection, and facilitates assembly and use.

[0023] 7. The cable core wire is sealed and fixed to the second through hole by a protective sleeve, the housing and cylinder are sealed by a first sealing ring, and the housing and cover are sealed by a second sealing ring, thereby improving the sealing performance of the magnetostrictive displacement sensor.

[0024] 8. When the torsional wave is transmitted to the waveguide wire at the detector coil, the waveguide wire undergoes a change in magnetic field under the inverse effect of magnetostriction. The detector coil generates a voltage when the magnetic field changes, and the detector printed circuit board sends the voltage signal to the main printed circuit board to realize the detection and transmission of the detection signal.

[0025] 9. The detector coil is set parallel to the axial direction of the waveguide wire outside the waveguide wire. Compared with the method of directly wrapping the detector coil outside the waveguide wire, the detector coil in this scheme is more sensitive to changes in the magnetic field of the waveguide wire and has better detection accuracy.

[0026] 10. A bias magnet is inserted inside the detector coil to further enhance the detector coil's sensitivity to the waveguide wire. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a magnetostrictive displacement sensor according to an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the sensor body according to an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of the structure of a magnetostrictive displacement sensor and a hydraulic cylinder according to an embodiment of the present invention.

[0030] Figure 4 This is a schematic diagram of the sensor body and housing according to an embodiment of the present invention.

[0031] In the picture: 1000 Magnetostrictive Displacement Sensor; 100 Position Magnetic Ring; 200 Sensor Body; 210 Main Printed Circuit Board; 211 Microprocessor Module; 212 Power Conversion Module; 213 Excitation Module; 214 Signal Processing Module; 215 Output Conversion Module; 220 Waveguide Wire; 230 Detector Assembly; 231 Detector Printed Circuit Board; 232 Detector Coil; 233 Bias Magnet; 234 Detector Mount; 235 Torsion Plate; 236 Detector Housing; 24 0. Strain gauge; 250. Return wire; 260. Waveguide sheath; 300. Cable core; 400. Housing; 410. First through hole; 420. Annular groove; 430. First sealing ring; 500. Housing cover; 510. Second through hole; 520. Cable sheath; 530. Second sealing ring; 540. Rubber gasket; 600. Outer housing; 610. Plug; 2000. Hydraulic cylinder; 2100. Cylinder body; 2110. Stepped section; 2200. Piston rod; 2210. Mounting hole. Detailed Implementation

[0032] The invention will now be further described with reference to the accompanying drawings.

[0033] This embodiment discloses a magnetostrictive displacement sensor 1000 for large-scale road maintenance machinery, referring to... Figures 1 to 3 In this embodiment, the magnetostrictive displacement sensor 1000 is used for displacement detection of the grinding head of a large track maintenance machine. The large track maintenance machine is mounted on the railway track. The grinding head is connected to the large track maintenance machine through a hydraulic cylinder 2000. The large track maintenance machine drives the grinding head to move close to the railway track surface for grinding and maintenance through the hydraulic cylinder 2000.

[0034] In this embodiment, a magnetostrictive displacement sensor 1000 is installed in the hydraulic cylinder 2000 of a large track maintenance machine. Specifically, the hydraulic cylinder 2000 includes a cylinder body 2100 and a piston rod 2200. The piston rod 2200 is axially slidably disposed in the cylinder body 2100, and a grinding head is connected to the end of the piston rod 2200 opposite to the cylinder body 2100. By detecting the displacement of the piston rod 2200 through the magnetostrictive displacement sensor 1000, the displacement of the grinding head can be detected.

[0035] Reference Figure 1 and Figure 2 In this embodiment, the magnetostrictive displacement sensor 1000 includes a position magnetic ring 100 and a sensor body 200. The position magnetic ring 100 is coaxially and fixedly connected to the piston rod 2200 of the hydraulic cylinder 200, and the sensor body 200 is fixedly disposed inside the hydraulic cylinder 2000. The sensor body 200 can detect the displacement of the position magnetic ring 100 relative to the sensor body 200. When the hydraulic cylinder 2000 extends and retracts to drive the grinding head to perform grinding operations, the position magnetic ring 100 extends and retracts with the piston rod 2200. Therefore, by measuring the displacement of the position magnetic ring 100 relative to the sensor body 200, the displacement of the grinding head can be measured.

[0036] Reference Figure 1 , Figure 2 and Figure 4 The sensor body 200 includes a main printed circuit board 210, a waveguide wire 220, and a detector assembly 230. The waveguide wire 220 is connected to the detector assembly 230, and the detector assembly 230 is connected to the main printed circuit board 210. The waveguide wire 220, the detector assembly 230, and the main printed circuit board 210 are fixedly disposed in the cylinder body 2100 of the hydraulic cylinder 2000. The main printed circuit board 210 is electrically connected to a cable core wire 300 for power supply and signal output. The cable core wire 300 passes through the cylinder body 2100 of the hydraulic cylinder 2000 and connects to an external vehicle power supply and an external control system, thereby powering the magnetostrictive displacement sensor 1000 and transmitting the displacement information detected by the magnetostrictive displacement sensor 1000 to the external control system.

[0037] In this embodiment, the waveguide wire 220 is a long linear magnetostrictive material, specifically made of a rare-earth-iron alloy. The waveguide wire 220 can be used to generate length or volume changes under the action of an external magnetic field, thereby generating a torsional wave.

[0038] Reference Figure 3 The piston rod 2200 of the hydraulic cylinder 2000 has an elongated mounting hole 2210 axially formed inside. The mounting hole 2210 opens towards the sensor body 200. The waveguide wire 220 passes through the position magnetic ring 100 and is installed in the mounting hole 2210, allowing it to move axially relative to the mounting hole 2210. The end of the waveguide wire 220 passes through the opening of the mounting hole 2210 and connects to the sensor body 200. Thus, when the piston rod 2200 moves, the position magnetic ring 100 can move relative to the waveguide wire 220.

[0039] The main printed circuit board 210 can send an excitation current signal to the waveguide wire 220. The excitation current propagates in the waveguide wire 220 at the speed of light, and the propagation time of the excitation current can be considered to be 0. Under the action of the excitation current signal, the waveguide wire 220 generates an Ampere ring magnetic field. At the position magnetic ring 100, the magnetic field of the waveguide wire 220 and the magnetic field of the position magnetic ring 100 are coupled. Due to the Widmann effect, a torsional wave is generated on the surface of the waveguide wire 220 at the position magnetic ring 100. When the torsional wave propagates in a straight line along the waveguide wire 220 to the detector assembly 230, the detector assembly 230 detects the torsional wave and outputs a detection signal to the main printed circuit board 210. The main printed circuit board 210 can calculate the location of the torsional wave based on the time difference between the excitation current signal and the detection signal and the propagation speed of the torsional wave, and thus know the displacement of the position magnetic ring 100 and the piston rod 2200.

[0040] Specifically, let v be the propagation speed of the torsional wave in the waveguide material, t be the time node when the main printed circuit board 210 sends out the excitation current signal, and T be the time node when the main printed circuit board 210 receives the detection signal sent by the detector component 230. Then the displacement X of the piston rod 2200 is ((Tt) / v).

[0041] In this embodiment, the magnetostrictive displacement sensor 1000 operates based on an excitation current signal. It only needs to measure the time interval between the excitation current signal and the detection signal. Since time signal detection technology is mature and can achieve high accuracy, displacement detection in this embodiment is more convenient and accurate. Furthermore, power interruption and subsequent restoration do not affect the received data. The signal does not require zero-return processing or amplification, and periodic recalibration is unnecessary, simplifying the complexity of the detection system and improving operability. The position magnetic ring 100 only needs physical fixing and requires no external circuitry, facilitating installation within the hydraulic cylinder 2000.

[0042] The magnetostrictive displacement sensor 1000 is installed inside the hydraulic cylinder 2000. It has good environmental adaptability and is not easily affected by the high temperature and dust environment during operation. The magnetostrictive displacement sensor 1000 adopts non-contact measurement. There is no direct contact between the position magnetic ring 100 and the sensor body 200. It is not easy to wear during measurement, eliminating the need for maintenance of the magnetostrictive sensor and extending its service life.

[0043] Reference Figure 2 The main printed circuit board 210 includes a microprocessor module 211, a power conversion module 212, an excitation module 213, a signal processing module 214, and an output conversion module 215. The power conversion module 212, excitation module 213, signal processing module 214, and output conversion module 215 are connected to the microprocessor module 211. A cable core 300 is connected to the power conversion module 212 and the output conversion module 215. The power conversion module 212 is used to input and convert power to the main printed circuit board 210. The main printed circuit board 210 converts the external voltage input from the cable core 300 into an internal voltage usable by the magnetostrictive displacement sensor 1000 through the power conversion module 212. The excitation module 213 is connected to the detector assembly 230 and communicates with the waveguide wire 220 through the detector assembly 230. The excitation module 213 is used to output excitation current signal pulses to the waveguide wire 220. The signal processing module 214 is connected to the detector assembly 230. The signal processing module 214 is used to receive the detection signal emitted by the detector assembly 230 and measure the time of receiving the detection signal. The microprocessor module 211 calculates the distance between the position magnetic ring 100 and the detector assembly 230 based on the time difference between the emitted excitation current signal and the received detection signal and the speed of the torsional wave propagating in the waveguide wire 220, and outputs the result through the output conversion module 215 via the cable core wire 300.

[0044] Reference Figure 2 The signal processing module 214 includes a frequency selective amplifier circuit, a comparison circuit, and a time measurement circuit. After the detection signal emitted by the detection component 230 is modulated by the frequency selective amplifier circuit and the comparison circuit, the time measurement circuit measures the time of receiving the detection signal and transmits it to the microprocessor module 211 (MCU).

[0045] Reference Figure 1 and Figure 2The detection assembly 230 includes a detection printed circuit board 231 and a detection coil 232. The detection printed circuit board 231 is electrically connected to the main printed circuit board 210, and the detection coil 232 is electrically connected to the detection printed circuit board 231. The detection coil 232 generates a voltage change when the waveguide wire 220 at the detection coil 232 generates a magnetic field change. When the torsional wave is transmitted to the waveguide wire 220 at the detection coil 232, the waveguide wire 220 undergoes a magnetic field change under the inverse effect of magnetostriction. The detection coil 232 generates a voltage when the magnetic field changes (i.e., in this embodiment, the detection signal is a voltage signal). The detection printed circuit board 231 sends the voltage signal to the main printed circuit board 210, realizing the detection and transmission of the detection signal.

[0046] Reference Figure 2 The detector printed circuit board 231 is equipped with a pre-filter circuit. The pre-filter circuit filters and adjusts the waveform of the voltage signal generated by the detector coil 232 and outputs it to the frequency selective amplifier circuit on the main printed circuit board 210.

[0047] Reference Figure 1 and Figure 2 In this embodiment, the axis of the detector coil 232 is parallel to the axis of the waveguide wire 220, and the waveguide wire 220 is disposed outside the detector coil 232. Since the Ampere magnetic field generated by the waveguide wire 220 under the action of the excitation current signal gradually decays outwards in a circular pattern, compared to the method of directly sleeved around the waveguide wire 220, the detector coil 232 is disposed parallel to the axis of the waveguide wire 220 in this scheme, making the detector coil 232 more sensitive to changes in the magnetic field of the waveguide wire 220 and resulting in better detection accuracy.

[0048] The detector coil 232 is equipped with a bias magnet 233, which guides the magnetic field generated by the waveguide wire 220 to further enhance the sensing sensitivity of the detector coil 232 to the waveguide wire 220.

[0049] In this embodiment, the detector coil 232 is specifically connected to the detector printed circuit board 231 via a detector mount, so that the detector coil 232 can be set coaxially with the waveguide wire 220. A torsion plate 235 is connected between the detector coil 232 and the waveguide wire 220, and the torsion plate 235 further connects the waveguide wire 220 and the detector assembly 230.

[0050] Reference Figure 2 and Figure 4 The detector assembly 230 also includes a detector housing 236, which covers the detector printed circuit board 231 and the detector coil 232. The detector housing 236 holds the detector assembly 230 together, facilitating the installation and transportation of the detector assembly 230.

[0051] Reference Figure 1One end of the waveguide wire 220 near the sensor body 200 is connected to the detector printed circuit board 231 via a strain gauge 240, achieving electrical connection between the waveguide wire 220 and the detector assembly 230. When a torsional wave is transmitted to the strain gauge 240, it can be absorbed by the deformation of the strain gauge 240. Preferably, a damper is connected to the end of the waveguide wire 220 away from the detector assembly 230, which absorbs the torsional waves propagating on the waveguide wire 220 in the direction away from the detector assembly 230.

[0052] The end of the waveguide wire 220 away from the detector coil 232 is connected to a return copper wire 250, which is connected to the detector printed circuit board 231, so that the waveguide wire 220 and the detector printed circuit board 231 are connected to form a circuit.

[0053] Reference Figure 1 and Figure 4 In this embodiment, a waveguide sheath 260 is provided on the outer cover of the waveguide wire 220. The waveguide wire 220 and the return copper wire 250 are housed in the waveguide sheath 260. The waveguide sheath 260 protects the waveguide wire 220 and the return copper wire 250, thereby improving the protection capability and service life of the waveguide wire 220.

[0054] The waveguide sleeve 260 is fixedly connected to the detector housing 236, so that the detector assembly 230, waveguide wire 220 and waveguide sleeve can be connected into a whole, which facilitates the transportation and installation of the magnetostrictive displacement sensor 1000.

[0055] Reference Figure 3 The detector assembly 230 and the main printed circuit board 210 are both located in the rodless chamber of the hydraulic cylinder 2000 at the end away from the piston rod 2200. That is, the sensor body 200 is located in the tail end of the hydraulic cylinder 2000. This arrangement makes it less likely for the detector assembly 230 and the main printed circuit board 210 to interfere with the normal extension and retraction of the piston rod 2200 of the hydraulic cylinder 2000, and reduces the probability of collision and wear between the detector assembly 230, the main printed circuit board 210 and the piston rod 2200.

[0056] Reference Figure 4 The sensor body 200 is surrounded by a housing 400 and a cover 500. The housing 400 is fixedly installed inside the cylinder body 2100 of the hydraulic cylinder 2000, and the cover 500 is detachably connected to the housing 400. The detector assembly 230 and the main printed circuit board 210 are installed between the housing 400 and the cover 500. The housing 400 and the cover 500 protect the detector assembly 230 and the main printed circuit board 210, reducing the impact of hydraulic oil on the detector assembly 230 and the main printed circuit board 210, and improving the IP protection capability of the magnetostrictive displacement sensor 1000.

[0057] In this embodiment, the housing 400 is open on the side facing the cover 500. After the detector assembly 230 is installed into the housing 400, the cover 500 is installed on the housing 400 to cover the opening. A first through-hole 410 communicating with the inner cavity of the housing 400 is provided on the side of the housing 400 facing the piston rod 2200. The waveguide wire 220 and the waveguide sheath 260 pass through the first through-hole 410 and are inserted into the mounting hole 2210 of the piston rod 2200. A second through-hole 510 is provided on the side of the cover 500 away from the housing 400. The cable core wire 300 passes through the second through-hole 510 and exits through the wiring hole on the cylinder body 2100, thereby connecting to the power supply and control system outside the cylinder 2000. This arrangement makes the overall structure of the magnetostrictive displacement sensor 1000 compact, provides good protection, and facilitates the assembly and use of the magnetostrictive displacement sensor 1000.

[0058] Reference Figure 4 An outer protective shell 600 is fixedly connected to one end of the housing 400 facing the piston rod 2200. The outer protective shell 600 is a long cylindrical shape, and the end of the outer protective shell 600 away from the housing 400 is sealed by a plug 610. The outer protective shell 600 is interference-fitted into the first through hole 410, and the waveguide wire 220 passes through the first through hole 410 and then passes through the outer protective shell 600. The outer protective shell 600 is made of rigid material and is axially movable in the mounting hole 2210.

[0059] Thus, the outer shell, the cover 500, and the outer protective shell 600 are connected to form a reliable sealed shell, which isolates the sensor body 200 from the internal space of the cylinder 2000, facilitates the modular installation of the magnetostrictive displacement sensor 1000, and improves the environmental tolerance of the magnetostrictive displacement sensor 1000.

[0060] Reference Figure 4 An annular groove 420 is formed on the outer periphery of the housing 400, and a first sealing ring 430 is embedded in the annular groove 420. The inner ring of the first sealing ring 430 fits against the bottom wall of the annular groove 420, and the outer periphery of the first sealing ring 430 seals against the inner wall of the cylinder 2000. Thus, the rod chamber of the cylinder 2000 is isolated by the first sealing ring 430, and the hydraulic oil in the rod chamber exists only between the piston rod 2200 and the end of the housing 400 facing the piston rod 2200. The cover 500 is located on the side of the housing 400 away from the piston rod 2200. Here, hydraulic oil is not likely to enter between the cover 500 and the housing 400 and affect the sensor body 200. At the same time, the sealing of the rodless chamber is ensured, and hydraulic oil leakage is not likely to occur due to the through hole on the cylinder body 2100 for the cable core wire 300 to pass through.

[0061] Reference Figure 3An annular stepped portion 2110 is provided in the rodless chamber of the hydraulic cylinder 2000. The side of the housing 400 facing away from the piston rod 2200 abuts against the stepped portion 2110 axially, thereby limiting the housing 400 in the axial direction of the hydraulic cylinder 2000. The hydraulic oil in the hydraulic cylinder 2000 acts on the side of the housing 400 facing the piston rod 2200, so that the housing 400 is stably abutted against the stepped portion 2110 and is not easily moved within the hydraulic cylinder 2000.

[0062] Reference Figure 4 A protective sleeve 520 is provided inside the second through hole 510, and the protective sleeve 520 is sealed outside the cable core 300. By sealing the second through hole 510 and the cable core 300 with the protective sleeve 520, the sealing performance of the space between the housing 400 and the cover 500 is further improved.

[0063] The cover 500 fits into the opening of the housing 400. A second sealing ring 530 is fitted around the outer periphery of the cover 500, and the outer ring of the second sealing ring 530 seals against the inner wall of the housing 400. A rubber sealing gasket 540 abuts against the inner wall of the housing 400 between the end face of the cover 500 facing the housing 400, further improving the sealing performance between the housing 400 and the cover 500.

[0064] In this embodiment, the main printed circuit board 210 is fixed to the housing cover 500 with screws, and the detector housing 236 is fixed inside the housing 400 with screws. In other embodiments, the sensor body 200 may also be connected to the housing 400 and housing cover 500 in other suitable ways.

[0065] Reference Figure 3 The position magnetic ring 100 is fixedly installed at the end of the piston rod 2200 facing the rodless cavity, which makes the distance between the position magnetic ring 100 and the sensor body 200 relatively short. When the piston rod 2200 extends outward to the cylinder 2100, the waveguide wire 220 is gradually pulled out of the mounting hole 2210 in the direction away from the piston rod 2200. During this process, the position magnetic ring 100 can remain sleeved on the outside of the waveguide wire 220, ensuring that the displacement measurement of the piston rod 2200 can be carried out normally.

[0066] Specifically, a groove is provided at one end of the piston rod 2200 facing the detector assembly 230. The groove extends in a ring around the mounting hole 2210. The position magnetic ring 100 is embedded in the groove and fixed to the piston rod 2200 by screws.

[0067] In this embodiment, the position magnetic ring 100, the mounting hole 2210 and the piston shaft are coaxially arranged, which facilitates the coaxial arrangement of the position magnetic ring 100 and the waveguide wire 220 and ensures the magnetostrictive effect of the waveguide wire 220.

[0068] The above description is only a preferred embodiment of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of this patent application are included in the scope of this patent application.

Claims

1. A magnetostrictive displacement sensor for a large road maintenance machine, characterized by, The magnetostrictive displacement sensor (1000) is arranged on the oil cylinder (2000) of the large-scale road maintenance machine; the magnetostrictive displacement sensor (1000) comprises a position magnetic ring (100) and a sensor main body (200), the position magnetic ring (100) is coaxially connected to the piston rod (2200) of the oil cylinder (2000), and the sensor main body (200) is fixedly arranged in the oil cylinder (2000). The sensor main body (200) comprises a main printed board (210), a waveguide wire (220) and a detection assembly (230), the waveguide wire (220) is connected to the detection assembly (230), and the detection assembly (230) is connected to the main printed board (210); the waveguide wire (220) and the detection assembly (230) are fixedly arranged in the cylinder body (2100) of the oil cylinder (2000), the main printed board (210) is electrically connected with a cable core wire (300) for power supply and signal output, and the cable core wire (300) penetrates out of the cylinder body (2100) of the oil cylinder (2000); the waveguide wire (220) is a long linear magnetostrictive material, the piston rod (2200) of the oil cylinder (2000) is provided with a mounting hole (2210), the waveguide wire (220) is arranged in the position magnetic ring (100) and mounted in the mounting hole (2210) and can axially move relative to the mounting hole (2210). The main printed board (210) can send an excitation current signal to the waveguide wire (220), the waveguide wire (220) generates a torsional wave at the position magnetic ring (100) under the action of the excitation current signal, and the detection assembly (230) can output a detection signal to the main printed board (210) when the torsional wave is detected.

2. A magnetostrictive displacement transducer for a large track maintenance machine as set forth in claim 1, wherein, The main printed board (210) comprises a microprocessor module (211), a power conversion module (212) connected to the microprocessor module (211), an excitation module (213), a signal processing module (214) and an output conversion module (215), the power conversion module (212) is used for inputting and converting power to the main printed board (210), the excitation module (213) is used for outputting an excitation current signal to the waveguide wire (220), the signal processing module (214) is used for receiving a detection signal sent by the detection assembly (230) and measuring the time of receiving the detection signal, and the microprocessor module (211) calculates the distance between the position magnetic ring (100) and the detection assembly (230) according to the time difference between sending the excitation current signal and receiving the detection signal and the speed of the torsional wave in the waveguide wire (220).

3. A magnetostrictive displacement transducer for a large track maintenance machine as set forth in claim 1, wherein, The detection assembly (230) and the main printed board (210) are arranged in the oil cylinder (2000) away from the piston rod (2200) at one end of the rodless cavity.

4. A magnetostrictive displacement transducer for a large track maintenance machine as claimed in claim 3, wherein, The position magnetic ring (100) is fixedly arranged at the end of the piston rod (2200) towards the rodless cavity, and the position magnetic ring (100), the mounting hole (2210) and the piston rod (2200) are coaxially arranged.

5. A magnetostrictive displacement transducer for a large track maintenance machine as set forth in claim 1, wherein, The waveguide wire (220) is sleeved with an outer sheath (600) made of hard material, and the outer sheath (600) is movably arranged in the mounting hole (2210) in the axial direction.

6. A magnetostrictive displacement transducer for a large track maintenance machine as defined in claim 5, wherein, The magnetostrictive displacement sensor (1000) further comprises a shell (400) and a shell cover (500), the shell (400) is fixedly arranged in the cylinder body (2100) of the oil cylinder (2000), the shell cover (500) is detachably connected to the shell (400), and the detection assembly (230) and the main printed board (210) are installed in the shell (400); the shell (400) is provided with a first through hole (410) communicating with the inner cavity of the shell (400), the outer sheath (600) is fixedly matched with the first through hole (410), the waveguide wire (220) passes through the first through hole (410) and is arranged in the outer sheath (600); the shell cover (500) is provided with a second through hole (510), and the cable core wire (300) passes through the second through hole (510).

7. A magnetostrictive displacement transducer for a large track maintenance machine as defined in claim 6, wherein, A wire protection sleeve (520) is sealingly arranged in the second through hole (510), and the wire protection sleeve (520) is sealingly sleeved on the cable core wire (300); The shell (400) is sleeved with a first sealing ring (430), and the outer periphery of the first sealing ring (430) sealingly abuts against the inner wall of the oil cylinder (2000); the shell cover (500) is matched in the opening of the shell (400), and the outer periphery of the shell cover (500) is sleeved with a second sealing ring (530), and the outer ring of the second sealing ring (530) sealingly abuts against the inner wall of the shell (400).

8. A magnetostrictive displacement transducer for a large track maintenance machine as set forth in claim 1, wherein, The detection assembly (230) comprises a detection printed board (231) and a detection coil (232), the detection printed board (231) is electrically connected to the main printed board (210), the detection coil (232) is electrically connected to the detection printed board (231), and the detection coil (232) can generate voltage change when the waveguide wire (220) at the detection coil (232) generates magnetic field change.

9. A magnetostrictive displacement transducer for a large track maintenance machine as defined in claim 8, wherein, The axis of the detection coil (232) is parallel to the axial direction of the waveguide wire (220), and the waveguide wire (220) is arranged outside the detection coil (232).

10. A magnetostrictive displacement transducer for a large track maintenance machine as defined in claim 9, wherein, The biasing magnetic steel (233) is arranged in the detection coil (232).

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