A dual-mode vibration hydraulic oil on-line viscosity detector

Abstract

The utility model discloses a kind of double-mode vibration hydraulic oil on-line viscosity detector, it is related to hydraulic system state monitoring technical field, including main body, alloy vibration rod and temperature compensation unit, two parallel arrangements and are presented alloy vibration rod of tuning fork type structure in main body one side is arranged, temperature compensation unit is set in alloy vibration rod front end, tail is connected with main body by fixing device. Circuit board is arranged in main body interior, circuit board is respectively connected with signal processing module, output module, main control PLC and power management module electricity, and output module is connected with the display arranged in the outside of main body;Main body is further provided with communication interface and power interface, and is connected with main control PLC and power management module respectively. The utility model obtains hydraulic oil vibration response by alloy vibration rod, and realizes the on-line detection of hydraulic oil viscosity in combination with temperature compensation, compact overall structure, without setting mechanical rotating part and throttling micropore.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic system condition monitoring, specifically a dual-mode vibration hydraulic oil online viscosity meter. Background Technology

[0002] With the development of high-load hydraulic equipment such as machine tools, construction machinery, wind power, and metallurgy towards higher efficiency and longer service life, the viscosity of hydraulic oil has become a key indicator determining system energy consumption, sealing reliability, and component wear rate. Therefore, directly and continuously acquiring oil viscosity information in the hydraulic circuit is gradually replacing offline laboratory testing and becoming an important part of intelligent maintenance. An existing hydraulic oil viscosity testing device (publication number: CN211927610U) has the following drawbacks and requires further improvement.

[0003] Traditional vibratory online viscometers mostly use a single resonance mode to sense oil damping. The measurement sensitivity decays rapidly outside a certain viscosity range. When the hydraulic oil temperature fluctuates drastically or the density changes, the drift of the resonance peak is prone to cross-interference with the viscosity change, which leads to the need for frequent offline calibration of the equipment or the addition of complex temperature compensation circuits.

[0004] Rotary or differential pressure online viscometers rely on mechanical rotating parts or micro-orifice throttling elements to obtain viscous resistance signals. Long-term operation can easily lead to problems such as shaft seal leakage, micro-orifice blockage, and adhesion wear. Utility Model Content

[0005] The main objective of this invention is to provide a dual-mode vibration hydraulic oil online viscosity meter, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a dual-mode vibration hydraulic oil online viscosity detector, wherein two alloy vibrating rods are provided on one side of the main body, a temperature compensation unit is provided at the front end of the alloy vibrating rods, a fixing device is provided at the tail end of the alloy vibrating rods, a status indication unit is provided inside the main body, a circuit board is provided inside the main body, the circuit board is electrically connected to a signal processing module, an output module, a main control PLC, and a power management module respectively, the output module is electrically connected to a display, and the display is located outside the main body, a communication interface and a power interface are provided on one side of the main body, the communication interface is connected to the main control PLC inside the main body, and the power interface is connected to the power management module inside the main body.

[0007] Preferably, the alloy vibrating rods are arranged in parallel and integrally formed in a tuning fork shape, with a free end spacing of 5mm. The roots are laser-welded to the same base plate, and the base plate is connected to the fixing device and integrally embedded in the left end face of the main body.

[0008] Preferably, the temperature compensation unit is a Pt1000 platinum resistance sensor, which is embedded in an axial blind hole with a diameter of 2.5 mm and a depth of 12 mm at the front end of the alloy vibrating rod, and the tail end of the blind hole is sealed with epoxy resin.

[0009] Preferably, the circuit board is 1.6mm thick and is fixed in a guide groove along the length of the main body by four Φ3mm copper pillars and M2.5 stainless steel screws.

[0010] Preferably, both the signal processing module and the output module are plug-in boards that are vertically inserted onto the circuit board. Each plug-in board is connected via a 2×10 pin header socket with a pitch of 2.54mm and an insertion force of 6N to 10N.

[0011] Preferably, the display is a 1.5-inch OLED panel, which is fixed to the outer right side of the main body with four M1.6 countersunk screws, and the display window is covered with 2mm thick tempered glass; the panel cable is a 12-core FFC, which is routed through a 4mm wide cable tray to the FFC socket on the circuit board.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] This invention simultaneously excites and tracks the fundamental bending mode and the second resonant mode in real time on the same alloy vibrating rod. By utilizing the difference in the sensitivity coefficients of the two modes to temperature and viscosity, a differential algorithm is used to automatically eliminate temperature drift and extend the measurement range.

[0014] This invention is a fully enclosed vibration measurement structure without rotating parts or throttling micro-holes. The alloy vibrator rod and oil circuit are sealed only by threads or flanges in one go, avoiding shaft seal leakage. The surface of the vibration probe is nitrided and hardened, and the amplitude is at the micrometer level, so it will not be worn or blocked by particle impact. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0016] In the diagram: 1. Main body; 2. Alloy vibrating rod; 3. Temperature compensation unit; 4. Fixing device; 5. Status indication unit; 6. Circuit board; 7. Signal processing module; 8. Output module; 9. Main control PLC; 10. Power management module; 11. Display; 12. Communication interface; 13. Power interface. Detailed Implementation

[0017] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0018] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0020] Example

[0021] Please see Figure 1 This utility model provides a technical solution:

[0022] A dual-mode vibration hydraulic oil online viscosity analyzer includes two alloy vibrating rods 2 on one side of the main body 1. Each alloy vibrating rod 2 has a temperature compensation unit 3 at its front end and a fixing device 4 at its rear end. The main body 1 contains a status indication unit 5 and a circuit board 6. The circuit board 6 is electrically connected to a signal processing module 7, an output module 8, a main control PLC 9, and a power management module 10. The output module 8 is electrically connected to a display 11, which is located outside the main body 1. The main body 1 has a communication interface 12 and a power interface 13 on one side. The communication interface 12 connects to the main control PLC 9 inside the main body 1, and the power interface 13 connects to the power management module 10 inside the main body 1.

[0023] Furthermore, the alloy vibrating rods 2 are arranged in parallel and integrally formed in the shape of tuning forks, with a free end spacing of 5mm. The roots are laser-welded to the same base plate, and the base plate is connected to the fixing device 4 and integrally embedded in the left end face of the main body 1.

[0024] Furthermore, the temperature compensation unit 3 is a Pt1000 platinum resistance sensor, which is embedded in an axial blind hole with a diameter of 2.5 mm and a depth of 12 mm at the front end of the alloy vibrating rod 2, and the tail end of the blind hole is sealed with epoxy resin.

[0025] Furthermore, the circuit board 6 is 1.6mm thick and is fixed to the guide rail groove set along the length direction inside the main body 1 by four Φ3mm copper pillars and M2.5 stainless steel screws.

[0026] Furthermore, both the signal processing module 7 and the output module 8 are plug-in boards that are vertically inserted onto the circuit board 6. Each plug-in board is connected via a 2×10 pin header socket with a pitch of 2.54mm, and the insertion force is 6N to 10N.

[0027] Furthermore, the display 11 is a 1.5-inch OLED panel, which is fixed to the outer right side of the main body 1 with four M1.6 countersunk screws, and the display window is covered with 2mm thick tempered glass; the panel cable is a 12-core FFC, which is routed through a 4mm wide cable tray to the FFC socket of the circuit board 6.

[0028] The main body is machined from a single piece of stainless steel with a hollow inner cavity. A fixing device is coaxially welded to the left end face. After pressing a nitrile rubber O-ring into the inside of the fixing device, the tuning fork alloy vibrator base plate is screwed and locked, so that the two vibrators extend 12mm parallel to the left end of the main body and are in direct contact with the hydraulic oil. A Φ2.5mm blind hole is drilled axially at the front end of each vibrator to embed a Pt1000 temperature compensation unit, which is then potted with epoxy. A dovetail guide rail is machined on each of the left and right sides of the inner wall of the main body, and the circuit board is fixed to it with four M2.5×6 stainless steel screws. The signal processing module and output module are vertically inserted into the middle and right end of the circuit board with 2×10 pitch 2.54mm pin headers. Three Φ5mm through holes are opened at the top, and a status indicator unit 5 composed of red, green and yellow LEDs is snapped in place from the inside out. A 14mm circular hole is cut into the right side wall of the main body, with an embedded M12A-coded 5-pin communication interface 12 and an M12A-coded 4-pin power interface. The two are connected to the output module and the power management module respectively via an oil-resistant shielded twisted pair cable. The 1.5-inch OLED display 11 is fixed to the outer right side wall of the main body with four M1.6 countersunk screws, and a 22mm × 15mm window is milled at the corresponding position and covered with 2mm tempered glass.

[0029] The piezoelectric drive / detection circuit is located on the left side of the circuit board: the drive end applies a sweep frequency excitation to the vibrating rod to simultaneously lock the fundamental bending mode f1≈6kHz and the secondary bending mode f2≈38kHz; the detection end acquires its amplitude and phase in real time. The obtained f1, f2 and corresponding quality factors Q1, Q2 are sent to the signal processing module via the SPI bus. The signal processing module has a built-in dual-mode differential viscosity model, which, combined with the temperature measurement results from temperature compensation unit 3, calculates the kinematic viscosity and generates a 4-20mA current and Modbus-RTU digital frames. These are then transmitted from the output module to the external main control PLC via the communication interface, while simultaneously driving the OLED to refresh real-time values ​​and controlling the LED to indicate the system status. The power management module converts the external 24VDC to 5V / 3.3V for the entire machine.

[0030] In the first 200 milliseconds after power-on, the external 24V DC power is distributed into three isolated buses of 12V, 5V and 3.3V through the power management module. Then, the signal processor reads the EEPROM, ADC, DAC and vibrating rod piezoelectric loop current in sequence. For any device that is disconnected or has excessive loop deviation, the yellow light is immediately lit and the output is frozen. At the same time, the 4kB frequency-temperature-viscosity lookup data in the EEPROM is loaded into the on-chip RAM, and the temperature drift and sensitivity coefficient are calculated and written into the register to prepare the benchmark for subsequent calculations.

[0031] Between 200 and 600 milliseconds, the digital synthesizer sweeps from 4 kHz to 50 kHz in 1 kHz steps, applying a square wave of ±12V to the vibrating rod. The FPGA locates the fundamental bending mode f1≈6 kHz and the secondary bending mode f2≈38 kHz from the FFT results, and sends these two frequencies into a second-order narrowband digital phase-locked loop (PLL). After the PLL converges with a 5 ms time constant, the drive signal turns sinusoidal, and the amplitude is automatically adjusted to keep the displacement of the vibrating rod tip at 0.9 μm. The quality factors Q1 and Q2 are refreshed with a 10 ms period.

[0032] After entering the stable operation phase, the resistance value of the Pt1000 temperature compensation unit is timestamped synchronously with the latest f1, f2, Q1, and Q2 and sent to the DSP. The algorithm first uses table lookup linear interpolation to give the initial viscosity, then uses the Q difference term to compensate for the residual damping error and uses the temperature difference term to offset the temperature drift, so that the whole machine can operate at -40℃ to +120℃ with a 10mm... 2 / s to 1000mm 2 Maintaining ±1% accuracy within the range of / s. If f1 drifts beyond 150Hz or Q1 drops below 60% of the calibrated value, it is determined that the probe is scaled or has air intake. The DSP writes a fault code and pulls the 4-20mA output to 3.6mA, while the LED flashes rapidly from green to red.

[0033] The analog output is linearly mapped from a 12-bit DAC to a 4-20mA current loop, and the digital data is refreshed via the M12 interface at 115200bps Modbus-RTU, and then refreshed again every second via I... 2 C-driven OLED panel displays viscosity and oil temperature in a scrolling manner; a three-color LED green light indicates normal operation, a slow-flashing yellow light indicates a warning, and a fast-flashing red light indicates failure, achieving dual visibility both on-site and remotely.

[0034] In the temperature rise test, when the system temperature rises from 25℃ to 90℃, the natural frequency of the vibrator decreases by 0.08% / ℃, but the dual-mode differential cancels out 92% of the temperature drift, and the viscosity curve shows no step change. When the oil emulsification with 1% water content causes the viscosity to drop sharply from 46 to 61 cSt and Q1, the device issues WARN-02 within 200ms and drives the PLC to bypass cooling. The high-frequency pulsation of 5MPa and 50Hz only brings ±12Hz random frequency deviation, which is effectively filtered out by the 20Hz bandwidth phase-locked loop.

[0035] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A dual-mode vibration hydraulic oil online viscosity meter, comprising a main body (1), an alloy vibrating rod (2), and a temperature compensation unit (3), characterized in that: Two alloy vibrating rods (2) are provided on one side of the main body (1). A temperature compensation unit (3) is provided at the front end of the alloy vibrating rod (2). A fixing device (4) is provided at the tail end of the alloy vibrating rod (2). A status indicator unit (5) is provided inside the main body (1). A circuit board (6) is provided inside the main body (1). The circuit board (6) is electrically connected to a signal processing module (7), an output module (8), a main control PLC (9), and a power management module (10). The output module (8) is electrically connected to a display (11), and the display (11) is located outside the main body (1). A communication interface (12) and a power interface (13) are provided on one side of the main body (1). The communication interface (12) is connected to the main control PLC (9) inside the main body (1), and the power interface (13) is connected to the power management module (10) inside the main body (1).

2. The dual-mode vibration hydraulic oil online viscosity meter according to claim 1, characterized in that: The alloy vibrating rods (2) are arranged in parallel and integrally formed in the shape of a tuning fork. The distance between their free ends is 5mm. The roots are laser-welded to the same base plate. The base plate is connected to the fixing device (4) and is integrally embedded in the left end face of the main body (1).

3. The dual-mode vibration hydraulic oil online viscosity meter according to claim 1, characterized in that: The temperature compensation unit (3) is a Pt1000 platinum resistance sensor, which is embedded in an axial blind hole with a diameter of 2.5 mm and a depth of 12 mm at the front end of the alloy vibrating rod (2). The tail end of the blind hole is sealed with epoxy resin.

4. The dual-mode vibration hydraulic oil online viscosity meter according to claim 1, characterized in that: The circuit board (6) is 1.6mm thick and is fixed in the guide groove set along the length direction inside the main body (1) by four Φ3mm copper pillars and M2.5 stainless steel screws.

5. The dual-mode vibration hydraulic oil online viscosity meter according to claim 1, characterized in that: The signal processing module (7) and the output module (8) are both plug-in boards that are vertically inserted into the circuit board (6). Each plug-in board is connected by a 2×10 pin header socket with a pitch of 2.54mm and an insertion force of 6N to 10N.

6. The dual-mode vibration hydraulic oil online viscosity meter according to claim 1, characterized in that: The display (11) is a 1.5-inch OLED panel, which is fixed to the outer right side of the main body (1) with four M1.6 countersunk screws. The display window is covered with 2mm thick tempered glass. The panel cable is a 12-core FFC, which is routed through a 4mm wide cable tray to the FFC socket of the circuit board (6).

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