Ultrasonic driving active probe based on air floating guide rail

Abstract

An ultrasonically driven active probe based on an air-bearing guide rail belongs to the fields of high-precision measurement and electromechanical technology. The device comprises two air-bearing short sleeves fixed to its base, with an air-bearing guide rail installed between the base and the air-bearing short sleeves. A rhomboid oscillator is installed in the middle of the guide rail, and a pre-tightening hinge is installed on the outer side of the rhomboid oscillator. The pre-tightening hinge and the rhomboid oscillator are interference-fitted. During operation, high-pressure gas is generated by a gas source, passes through a purification device and a pressure regulating valve, enters the air inlet, and then sequentially passes through the transverse main air channel, the vertical main air channel, and the longitudinal main air channel. Finally, it passes through several branch air channels and enters the gap between the air-bearing guide rail and the air-bearing working surfaces A, B, C, and D through a throttle device. At this time, the air-bearing guide rail is in a suspended state with almost no friction. Because the probe, air-bearing short sleeves, air-bearing guide rail, rhomboid oscillator, metal target, and capacitive sensor are mounted on the same axis, there is no Abbe error, thus improving accuracy.

Description

Technical Field

[0001] This invention relates to a contact-type active probe, specifically to an ultrasonically driven active probe based on an air-bearing guide rail. Background Technology

[0002] Micro-displacement measuring devices are widely used in high-end equipment and intelligent devices such as precision machining, intelligent manufacturing, and instrumentation. Currently, the methods and structures for micro-displacement measurement struggle to simultaneously achieve optimal performance in terms of measurement accuracy, measuring force, and device size, thus failing to meet the high-precision measurement requirements of micro-displacements. This invention designs an active probe that uses an air-bearing guide rail as a guiding mechanism to reduce friction in the direction of motion. A rhombic oscillator drives the air-bearing guide rail, reducing the trigger force of the probe. A capacitive sensor is used as the measuring device to achieve micro-displacement measurement. The probe device achieves high precision while also featuring a compact structure.

[0003] The published patent CN111947571A is a micro-force measuring three-dimensional integrated thread measuring machine probe. The transverse and longitudinal micro-displacement measuring systems measure the micro-displacement in the horizontal and vertical directions, respectively. It uses a parallel spring as a guide mechanism and a grating ruler to measure the micro-displacement. The device has a complex structure and is not small enough.

[0004] The published patent CN115325943A is a high-resolution displacement measurement device. It measures the frequency change of the dual longitudinal modes of a laser using a high-frequency photodetector, splits the dual longitudinal modes using a beam splitter, measures the light intensity using a photodetector, and calculates the target displacement from the positive and negative values ​​of the light intensity change and the frequency change value. However, this device is susceptible to the influence of external light sources and other factors, which reduces the measurement accuracy.

[0005] The published patent CN107240422A is a pneumatic precision positioning mechanism with piezoelectric micro-displacement compensation. It uses a cylinder to amplify the output displacement of the piezoelectric ceramic and measures the displacement through a grating sensor to achieve high-precision positioning with a large stroke. This device is a high-precision positioning with a large stroke, but its size is not small enough.

[0006] The published patent CN114252001A is a parallel calibration device for an eddy current micro-displacement sensor. It uses an inner micrometer to push a flexible steel plate on the support frame of the object being measured. The deformation of the flexible steel plate causes the object being measured to move horizontally, and the displacement of the object being measured is measured by the eddy current sensor. This device cannot control the measuring force.

[0007] In summary, there are currently very few micro-displacement measurement devices that can simultaneously achieve high precision, miniaturized structure, and miniaturized measurement force. Summary of the Invention

[0008] The present invention aims to overcome the shortcomings of the prior art by providing an ultrasonically driven active probe based on an air-bearing guide rail.

[0009] The technical solution adopted in this invention is as follows:

[0010] An ultrasonically driven active probe based on an air-bearing guide rail includes a probe, a base, a sensor housing, a motor housing, and an air source. Two air-bearing short sleeves are fixedly connected to the base, and an air-bearing guide rail is installed between the base and the air-bearing short sleeves.

[0011] The inner side of the air-bearing short sleeve is machined with air-bearing working surfaces A, B, and C, and the upper part of the base is machined with air-bearing working surface D. The air-bearing guide rail is clearance-fitted with air-bearing working surfaces A, B, C, and D, with a clearance range of 7-12 micrometers.

[0012] Several branch air passages are machined perpendicular to surfaces A, B, C, and D. Throttling devices are installed at the outlets of the branch air passages leading to surfaces A, B, C, and D, and sealing plugs are installed at the outlets of the branch air passages leading to surfaces E and F.

[0013] To ensure interconnection between the branch air channels, several through longitudinal main air channels are machined on the outer surface M of the base and the air-float short sleeve, and air-sealing plugs are installed on both sides of the longitudinal main air channels.

[0014] To ensure interconnection between the longitudinal main air channels, several transverse main air channels are machined perpendicular to surface E. An air inlet is provided on one side of each transverse main air channel, and air plugs are installed at the remaining outlets. To connect the air passage between the air flotation sleeve and the base, vertical main air channels are machined perpendicular to surface P of the base and surface Q of the air flotation sleeve. A sealing ring is installed between surface P and surface Q to connect the vertical main air channels. The air inlet is connected to the air supply pipeline. Before entering the air inlet, the gas needs to pass through the air source, purification device, and pressure regulating valve in sequence.

[0015] A probe and a metal target are fixedly connected to both ends of the air-bearing guide rail. A groove is machined in the middle of the air-bearing guide rail, and a rhomboid oscillator is fixedly connected in the groove. Four piezoelectric ceramics are attached to the rhomboid oscillator. A pre-tightening hinge is interference-fitted to the periphery of the rhomboid oscillator. The top of the pre-tightening hinge is fixedly connected to the motor housing. The capacitive sensor is placed opposite the metal target. The capacitive sensor is mounted on the base through a fixing seat. The sensor housing covers the capacitive sensor and the fixing seat and is fixedly connected to the base.

[0016] During operation, high-pressure gas is generated by the gas source, enters the air inlet through the purification device and pressure regulating valve, and then passes through the transverse main air channel, vertical main air channel and longitudinal main air channel in sequence. Finally, it enters the gap between the air flotation guide rail and the air flotation working surfaces A, B, C and D through several branch air channels and the throttle device. At this time, the air flotation guide rail is in a suspended state and does not contact the air flotation short sleeve, so there is almost no friction.

[0017] The motor housing, air-bearing short sleeve, and sensor mounting base are installed on the same reference plane as the base, thus ensuring that the probe, air-bearing short sleeve, air-bearing guide rail, rhombic oscillator, metal target, and capacitive sensor are installed on the same axis. When the probe is actively triggered, a sinusoidal current with a phase difference is applied to the piezoelectric ceramic, which drives the rhombic oscillator to generate high-frequency elliptical motion. Although the rhombic oscillator is interference-fitted with the pre-tightening hinge, the pre-tightening hinge can generate elastic deformation under force, thus driving the rhombic oscillator and the air-bearing guide rail to move linearly, thereby driving the probe to move along the guide rail. When the probe contacts the surface being measured, the relative displacement between the metal target and the capacitive sensor changes, and the capacitance value changes, serving as the trigger sampling signal for the probe. When the piezoelectric ceramic is not energized, the rhombic oscillator is interference-fitted with the pre-tightening hinge, the relative position between the metal target and the capacitive sensor is fixed, the probe is in a locked state, and there is no sampling signal.

[0018] The ultrasonically driven active probe based on an air-bearing guide rail of the present invention has the following characteristics and advantages compared with existing micro-displacement measurement devices:

[0019] 1. High measurement accuracy. This invention is a contact probe, and the accuracy of contact measurements is inherently higher than that of non-contact measurements. It employs an air-bearing guide rail, and the air-bearing short sleeve and base include an air inlet, branch air channels, a vertical main air channel, a longitudinal main air channel, and a transverse main air channel. High-pressure gas enters the four air-bearing working surfaces A, B, C, and D through each air channel via a throttle, providing high-precision guidance for the probe. Furthermore, the use of a rhomboid oscillator drive enables low-speed, high-precision movement, and combined with a capacitive sensor, ensures the probe's high accuracy.

[0020] 2. Low measuring force. A significant factor affecting the accuracy of contact probes is the presence of contact measuring force. This invention utilizes an air-bearing guide rail with virtually no friction in the direction of probe movement. The driving force of the rhomboid oscillator is the trigger force for the probe's measurement. Therefore, the driving force can be reduced by adjusting the input power and voltage of the piezoelectric ceramic, thereby ensuring the probe's minimal measuring force.

[0021] 3. Small probe size. Compared with existing technologies, this invention designs a compact and small probe structure while maintaining the above performance. A small-volume rhombic oscillator is installed in the middle of a small air-bearing guide rail. Small-sized probes and metal targets are fixed to both sides of the air-bearing guide rail, respectively. The overall probe is slender, ensuring contact measurement under narrow measurement conditions. Existing technologies can also make the probe slender, but the error introduced by probe deformation will directly affect the measurement results. Our solution can send a sampling signal when the probe just deforms (i.e., when the triggering measurement force is very small), reducing the measurement error introduced by probe deformation. When not measuring, the rhombic oscillator forms a self-locking mechanism with the pre-tightening hinge, thereby ensuring the repeatability and accuracy of the probe. Attached Figure Description

[0022] Figure 1 Schematic diagram of an ultrasonic-driven active probe structure based on an air-bearing guide rail;

[0023] Figure 2 Left view of the core components of the probe;

[0024] Figure 3 Sectional view of probe I-I;

[0025] Figure 4 Cross-sectional view of the air flotation short sleeve and base;

[0026] Figure 5 Sectional view of probe II-II;

[0027] Figure 6 Schematic diagram of the internal structure of the probe (without the outer shell);

[0028] Figure 7 Schematic diagram of the rhombic oscillator and piezoelectric ceramic structure;

[0029] In the diagram: 1. Probe; 2. Base; 3. Sensor housing; 4. Motor housing; 5. Air source; 6. Air float sleeve; 7. Air float guide rail; 8. Branch air passage; 9. Throttling device; 10. Sealing plug; 11. Longitudinal main air passage; 12. Transverse main air passage; 13. Air inlet; 14. Vertical main air passage; 15. Sealing ring; 16. Air supply pipeline; 17. Purification device; 18. Pressure regulating valve; 19. Metal target; 20. Groove; 21. Rhomboid vibrator; 22. Piezoelectric ceramic; 23. Pre-tightened hinge; 24. Capacitive sensor; 25. Mounting base. Detailed Implementation

[0030] To make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention will be further described below in conjunction with specific embodiments.

[0031] Reference Figure 1 and Figure 2 This invention proposes an ultrasonically driven active probe based on an air-bearing guide rail, comprising a probe 1, a base 2, a sensor housing 3, a motor housing 4, and an air source 5. Two air-bearing short sleeves 6 are fixedly connected to the base 2, and an air-bearing guide rail 7 is installed between the base 2 and the air-bearing short sleeves 6. The inner side of the air-bearing short sleeves 6 is machined with air-bearing working surfaces A, B, and C, and the upper part of the base 2 is machined with an air-bearing working surface D. The air-bearing guide rail 7 is clearance-fitted with the air-bearing working surfaces A, B, C, and D, with a clearance range of 7-12 micrometers.

[0032] Reference Figure 3 Several branch air passages 8 are machined perpendicular to surfaces A, B, C, and D. Throttling devices 9 are installed at the outlets of branch air passages 8 leading to surfaces A, B, C, and D. Air sealing plugs 10 are installed at the outlets of branch air passages 8 leading to surfaces E and F.

[0033] Reference Figure 4 In order to make the branch air passages 8 interconnected, the outer surface M of the base 2 and the air flotation sleeve 6 is machined with several through longitudinal main air passages 11, and air sealing plugs 10 are installed on both sides of the longitudinal main air passages 11.

[0034] Reference Figure 5 To enable the longitudinal main air passages 11 to be interconnected, several transverse main air passages 12 are machined perpendicular to surface E. One side of each transverse main air passage 12 has an air inlet 13, and the remaining outlets are fitted with sealing plugs 10. To enable the air passages of the air flotation sleeve 6 and the base 2 to be connected, vertical main air passages 14 are machined perpendicular to surface P of the base 2 and surface Q of the air flotation sleeve 6. A sealing ring 15 is installed between surface P and surface Q to connect the vertical main air passages 14. The air inlet 13 is connected to the air supply pipeline 16. Before the gas enters the air inlet 13, it needs to pass through the air source 5, the purification device 17, and the pressure regulating valve 18 in sequence.

[0035] Reference Figure 6 and Figure 7 The air-bearing guide rail 7 has a probe 1 and a metal target 19 fixedly connected to both ends. The air-bearing guide rail 7 has a groove 20 machined in the middle. A rhomboid oscillator 21 is fixedly connected in the groove 20. Four piezoelectric ceramics 22 are attached to the rhomboid oscillator 21. A pre-tightening hinge 23 is interference-fitted to the periphery of the rhomboid oscillator 21. The upper part of the pre-tightening hinge 23 is fixedly connected to the motor housing 4. The capacitance sensor 24 is placed opposite the metal target 19. The capacitance sensor 24 is mounted on the base 2 through the fixing seat 25. The sensor housing 3 covers the capacitance sensor 24 and the fixing seat 25 and is fixedly connected to the base 2.

[0036] During operation, high-pressure gas is generated by gas source 5, enters air inlet 13 through purification device 17 and pressure regulating valve 18, and then passes through transverse main air channel 12, vertical main air channel 14 and longitudinal main air channel 11 in sequence from air inlet 13. Finally, it passes through several branch air channels 8 and enters the gap between air flotation guide rail 7 and air flotation working surfaces A, B, C and D through throttle device 9. At this time, air flotation guide rail 7 is in a suspended state and does not contact air flotation short sleeve 6, so there is almost no friction.

[0037] The motor housing 4, the air-bearing short sleeve 6, and the sensor mounting base 25 are installed on the same reference plane as the base 2, thereby ensuring that the probe 1, the air-bearing short sleeve 6, the air-bearing guide rail 7, the rhombic oscillator 21, the metal target 19, and the capacitive sensor 24 are installed on the same axis. When the probe is actively triggered, a sinusoidal current with a phase difference is passed through the piezoelectric ceramic 22, which drives the rhombic oscillator 21 to generate high-frequency elliptical motion. Although the rhombic oscillator 21 is interference-fitted with the pre-tightening hinge 23, the pre-tightening hinge 23 can generate its own elasticity after being subjected to force. The piezoelectric ceramic 22 deforms, thus driving the rhombic oscillator 21 and the air-bearing guide rail 7 to move linearly, which in turn drives the probe 1 to move along the guide rail. When the probe 1 contacts the surface being measured, the relative displacement between the metal target 19 and the capacitance sensor 24 changes, and the capacitance value changes, serving as the trigger sampling signal for the probe. When the piezoelectric ceramic 22 is not energized, the rhombic oscillator 21 and the pre-tightening hinge 23 are interference-fitted, the relative position between the metal target 19 and the capacitance sensor 24 is fixed, and the probe 1 is in a locked state, at which time there is no sampling signal.

Claims

1. An ultrasonically driven active probe based on an air-bearing guide rail, comprising a probe (1), a base (2), a sensor housing (3), a motor housing (4), and an air source (5), characterized in that: Two air-floating short sleeves (6) are fixedly connected to the base (2), and an air-floating guide rail (7) is installed between the base (2) and the air-floating short sleeves (6); The inner side of the air-floating short sleeve (6) is machined with air-floating working surfaces A, B, and C, and the upper part of the base (2) is machined with air-floating working surface D. The air-floating guide rail (7) is clearance-fitted with air-floating working surfaces A, B, C, and D, with a clearance range of 7-12 micrometers. Several branch air passages (8) are machined perpendicular to surfaces A, B, C, and D respectively. Throttling devices (9) are installed at the outlets of the branch air passages (8) leading to surfaces A, B, C, and D. Air sealing plugs (10) are installed at the outlets of the branch air passages (8) leading to surfaces E and F. In order to make the branch air passages (8) interconnected, the outer surface M of the base (2) and the air-float short sleeve (6) is machined with several through longitudinal main air passages (11), and air-sealing plugs (10) are installed on both sides of the longitudinal main air passages (11). To enable the longitudinal main air passages (11) to be interconnected, several transverse main air passages (12) are machined perpendicular to surface E. An air inlet (13) is left on one side of the transverse main air passage (12), and the remaining outlets are fitted with air-sealing plugs (10). To enable the air passages of the air-floating short sleeve (6) and the base (2) to be connected, vertical main air passages (14) are machined perpendicular to surface P of the base (2) and surface Q of the air-floating short sleeve (6). A sealing ring (15) is installed between surface P and surface Q to connect the vertical main air passages (14). The air inlet (13) is connected to the air supply pipeline (16). Before the gas enters the air inlet (13), it needs to pass through the air source (5), the purification device (17), and the pressure regulating valve (18) in sequence. The air-bearing guide rail (7) has a probe (1) and a metal target (19) fixedly connected at both ends. The air-bearing guide rail (7) has a groove (20) machined in the middle. A rhombic oscillator (21) is fixedly connected in the groove (20). Four piezoelectric ceramics (22) are pasted on the rhombic oscillator (21). A pre-tightening hinge (23) is interference-fitted on the periphery of the rhombic oscillator (21). The top of the pre-tightening hinge (23) is fixedly connected to the motor cover (4). The capacitance sensor (24) is placed opposite the metal target (19). The capacitance sensor (24) is mounted on the base (2) through the fixing seat (25). The sensor cover (3) wraps the capacitance sensor (24) and the fixing seat (25) and is fixedly connected to the base (2). During operation, high-pressure gas is generated by the gas source (5), enters the air inlet (13) through the purification device (17) and pressure regulating valve (18), and then passes through the transverse main air channel (12), vertical main air channel (14) and longitudinal main air channel (11) in sequence through the air inlet (13). Finally, it passes through several branch air channels (8) and enters the gap between the air flotation guide rail (7) and the air flotation working surfaces A, B, C and D through the throttle (9). At this time, the air flotation guide rail (7) is in a suspended state and does not contact the air flotation short sleeve (6), so there is almost no friction. The motor housing (4), the air-bearing short sleeve (6), and the sensor mounting base (25) are installed on the same reference plane as the base (2), thereby ensuring that the probe (1), the air-bearing short sleeve (6), the air-bearing guide rail (7), the rhombic oscillator (21), the metal target (19), and the capacitive sensor (24) are installed on the same axis. When the probe is actively triggered, a sinusoidal current with a phase difference is passed through the piezoelectric ceramic (22), which can drive the rhombic oscillator (21) to generate high-frequency elliptical motion. Although the rhombic oscillator (21) is interference-fitted with the pre-tightening hinge (23), the pre-tightening hinge (23) can itself be subjected to force. Elastic deformation occurs, thus driving the rhomboid oscillator (21) and the air-bearing guide rail (7) to move linearly, which in turn drives the probe (1) to move along the guide rail direction; when the probe (1) contacts the surface being measured, the relative displacement between the metal target (19) and the capacitance sensor (24) changes, and the capacitance value changes, which serves as the trigger sampling signal for the probe; when the piezoelectric ceramic (22) is not energized, the rhomboid oscillator (21) and the pre-tightening hinge (23) are interference-fitted, the relative position between the metal target (19) and the capacitance sensor (24) is fixed, the probe (1) is in a locked state, and there is no sampling signal at this time.

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