Micro air floating measuring head based on patch motor driving

Abstract

A miniature air-bearing probe based on a patch motor drive belongs to the fields of high-precision measurement and electromechanical technology. The device comprises two air-bearing short sleeves fixed to a base, with an air-bearing guide rail installed between the base and the air-bearing short sleeves. A patch motor is mounted in the middle of the guide rail, and a pre-tensioned hinge is mounted on the outer side of the patch motor. The pre-tensioned hinge and the drive foot of the patch motor are in an interference fit. The air-bearing sleeves, motor housing, and mounting base are all mounted on the same reference plane of the base. Specifically, the air-bearing guide rail achieves frictionless linear motion in the probe's direction of movement. The patch motor drive enables low-speed, high-precision motion, and the combination of a laser sensor ensures the probe's high accuracy. Therefore, the device of this invention has no Abbe error in principle and has the advantages of low triggering force and high measurement accuracy.

Description

Technical Field

[0001] This invention relates to a contact probe, specifically a miniature air-bearing probe driven by a patch motor. 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 a miniature air-bearing probe based on a patch motor. It utilizes an air-bearing guide rail as a guiding mechanism, drives the air-bearing guide rail with a patch motor, and measures the probe's feed displacement using a laser sensor. The probe moves without friction in its direction of motion, thereby reducing the trigger force, ensuring high measurement accuracy, and simultaneously achieving miniaturization.

[0003] The published patent CN217442505U is a monocular vision measurement device that uses a motor shaft to drive a lead screw to adjust the position of the target surface. When a target object is placed on the target surface, the light spot formed on the target surface changes its imaging position in the camera through a lens and a screen, thus achieving the measurement of the thickness of the target object. However, the device has a non-compact structure and is not miniaturized.

[0004] The published patent CN102175158A is a micro-displacement sensor based on optical rotation effect. The polarizing prism, optical rotation crystal and optical pickup prism are arranged on the same straight line. The displacement change is converted into measurable polarized light through the connection of the measuring rod to the optical rotation crystal, thereby realizing the measurement of micro-displacement. This device cannot provide a small measuring force.

[0005] The published patent CN117091487A is a pneumatic high-precision inductive displacement sensor. It guides the guide rod through a ball bearing, and the pneumatic component and reset component realize the reciprocating motion of the guide rod. The displacement is converted into inductance through a coil. The structure of this device is complex and its size is not small enough.

[0006] The published patent CN115523844A is a fiber optic grating micro-displacement sensor. It uses a movable lever mechanism to convert the minute displacement of the measured object into the displacement of an arc-shaped toothed rod, which drives a beam of equal strength to bend. The amplified displacement change is obtained through the fiber optic grating. This device is susceptible to the influence of external factors such as temperature, which reduces the measurement accuracy.

[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] This invention aims to overcome the shortcomings of existing technologies by providing a miniature air-bearing probe based on a surface-mount motor drive.

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

[0010] A miniature air-bearing probe driven by a patch motor includes a base and a probe. The base is characterized by having two air-bearing sleeves fixedly connected to it. An air-bearing guide rail is installed between the base and the two air-bearing sleeves. A beam is machined in the middle of the air-bearing guide rail, and several bosses are machined on both sides of the beam. A patch motor is mounted on each boss, and positioning holes are machined on the patch motors to allow them to be symmetrically mounted on both sides of the beam. Two piezoelectric ceramics are mounted inside each patch motor. Several driving feet are machined or mounted on the patch motors, and the driving feet are interference-fitted with the inner side of a pre-tightening hinge. The upper part of the pre-tightening hinge is fixed to a motor housing by screws. The motor housing is installed between the two air-bearing sleeves and fixed to the base. A probe is fixedly connected to one end of the air-bearing guide rail, and a laser sensor is mounted on the other side. The laser sensor is mounted on the base via a mounting bracket, and a sensor housing is mounted above the laser sensor and fixed to the base.

[0011] During installation, a gap is left between the air bearing sleeve and the air bearing guide rail, with a gap range of 7-12 micrometers on one side. During operation, high-pressure gas is introduced through the air bearing sleeve and enters this gap. At this time, the air bearing guide rail is in a suspended state, and the air bearing guide rail and the air bearing sleeve do not contact each other and there is no friction. When a sinusoidal current with a phase difference is applied to the piezoelectric ceramic, the drive foot of the patch motor can be driven to generate a high-frequency elliptical motion. Although the drive foot is interference-fitted with the pre-tightening hinge, the pre-tightening hinge can generate elastic deformation after being stressed. Therefore, it drives the patch motor to move along the guide rail, which in turn drives the air bearing guide rail and the probe to move along the guide rail direction.

[0012] The air bearing sleeve, motor housing, and mounting base are all installed on the same reference plane of the base, thus ensuring that the probe, air bearing sleeve, air bearing guide rail, patch motor, and laser sensor are installed on the same axis. When the probe is working, the drive foot on the patch motor drives the air bearing guide rail to move linearly. The air bearing guide rail drives the probe fixed to it to move, so that the probe contacts the surface being measured. The relative distance between the air bearing guide rail and the laser sensor changes. The displacement calculated by the laser sensor is the feed displacement of the probe relative to the surface being measured.

[0013] The driving method of the air-bearing guide can be outward support hinge type, inward extrusion hinge type and inward extrusion spring type. The inward extrusion spring type includes spring and annular groove. The probe has active triggering and self-locking functions. When actively triggered, the piezoelectric ceramic is energized and the patch motor drives the air-bearing guide and probe to make linear motion. The displacement of the motion is measured by the laser sensor and can be used as the sampling signal of the probe. When the piezoelectric ceramic is not energized, the driving foot is interference-fitted with the pre-tightening hinge, the relative position of the air-bearing guide and the laser sensor is fixed, and the probe (2) can be in the locked state. At this time, there is no sampling signal.

[0014] The present invention provides a miniature air-bearing probe based on a patch motor drive, which has the following characteristics and advantages compared with existing micro-displacement measurement devices:

[0015] 1. High measurement accuracy and wide applicability. This invention is a contact probe, and the accuracy of contact measurement is inherently higher than that of non-contact measurement. This invention utilizes a miniature probe and an air-bearing guide rail to transmit geometric quantities that are inconvenient to measure by contact, and then uses a high-precision, stable laser sensor to read the displacement. Specifically, the air-bearing guide rail achieves frictionless linear motion in the direction of probe movement, and a surface-mount motor drive enables low-speed, high-precision movement. Combined with the laser sensor, the high accuracy of the probe is guaranteed.

[0016] 2. The probe has an active triggering function. Traditional probes are mounted on an external motion mechanism, or the workpiece is mounted on a motion mechanism for measurement, and the measurement accuracy is greatly affected by the external motion mechanism. This invention enables the probe to have a micro-feed function and a high-precision air-bearing guide rail for motion guidance. The feed amount and measuring force can also be actively controlled, thereby improving the measurement accuracy.

[0017] 3. 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, resulting in almost no friction in the probe's direction of movement. The driving force of the patch motor 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.

[0018] 4. Small probe size. Compared with existing technologies, this invention designs a compact and small probe structure while maintaining the above performance. A small-volume patch motor is installed in the middle of a small air-bearing guide rail, and small-sized probes and laser sensors 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 begins to deform (i.e., when the triggering measurement force is very small), reducing the measurement error introduced by probe deformation. When not measuring, the patch motor forms a self-locking mechanism with the pre-tightening hinge, thereby ensuring the repeatability and accuracy of the probe measurement. Attached Figure Description

[0019] Figure 1 Schematic diagram of the external structure of the air-float probe;

[0020] Figure 2 Schematic diagram of air-bearing guide rail components;

[0021] Figure 3 Schematic diagram of the air-float probe (without the outer shell);

[0022] Figure 4 Schematic diagram of surface mount motor components;

[0023] Figure 5 Schematic diagram of the contact between the patch motor and the preloaded hinge;

[0024] Figure 6 Schematic diagram of motor housing and pre-tensioned hinge installation;

[0025] Figure 7 Schematic diagram of an inwardly extruded hinged air-bearing guide rail structure;

[0026] Figure 8 Schematic diagram of the installation of an inwardly pressing hinged air-float probe;

[0027] Figure 9 Schematic diagram of an inwardly compressed spring-type air-bearing guide rail structure;

[0028] Figure 10 Schematic diagram of the installation of an inwardly pressing spring-type air-float probe;

[0029] In the diagram: 1. Base; 2. Probe; 3. Air bearing sleeve; 4. Air bearing guide rail; 5. Beam; 6. Boss; 7. Patch motor; 8. Positioning hole; 9. Piezoelectric ceramic; 10. Drive foot; 11. Preload hinge; 12. Motor housing; 13. Screw; 14. Laser sensor; 15. Fixing base; 16. Sensor housing; 17. Spring; 18. Annular groove. 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] Example 1: Outward-supporting hinge type, refer to Figure 1 , Figure 2 and Figure 3This invention proposes a miniature air-bearing probe driven by a patch motor, comprising a base 1 and a probe 2. Two air-bearing sleeves 3 are fixedly connected to the base 1. An air-bearing guide rail 4 is installed between the base 1 and the two air-bearing sleeves 3. A beam 5 is machined in the middle of the air-bearing guide rail 4, and several bosses 6 are machined on both sides of the beam 5. A patch motor 7 is mounted on the bosses 6, and positioning holes 8 are machined on the patch motor 7. The positioning holes 8 allow the patch motor 7 to be symmetrically mounted on both sides of the beam 5. Two piezoelectric ceramics 9 are mounted inside each patch motor 7. Several drive feet 10 are machined or installed. The drive feet 10 are interference-fitted with the inner side of the pre-tightening hinge 11. The upper part of the pre-tightening hinge 11 is fixed to the motor housing 12 by screws 13. The motor housing 12 is installed between two air-bearing sleeves 3 and fixed to the base 1. One end of the air-bearing guide rail 4 is fixed to the probe 2, and the other side is equipped with a laser sensor 14. The laser sensor 14 is installed on the base 1 through the fixing seat 15. A sensor housing 16 is installed above the laser sensor 14 and is fixed to the base 1.

[0032] During installation, a gap is left between the air-bearing sleeve 3 and the air-bearing guide rail 4, with the gap on one side ranging from 7 to 12 micrometers. During operation, high-pressure gas is introduced into the air-bearing sleeve 3 and enters the gap. At this time, the air-bearing guide rail 4 is in a suspended state, and the air-bearing guide rail 4 and the air-bearing sleeve 3 do not contact each other and there is no friction. When a sinusoidal current with a phase difference is applied to the piezoelectric ceramic 9, the drive foot 10 of the patch motor 7 can be driven to generate high-frequency elliptical motion. Although the drive foot 10 is interference-fitted with the pre-tightening hinge 11, the pre-tightening hinge 11 can generate elastic deformation after being subjected to force, thus driving the patch motor 7 to move along the guide rail, which in turn drives the air-bearing guide rail 4 and the probe 2 to move along the guide rail direction.

[0033] Reference Figure 5 , Figure 6 and Figure 7 The air-bearing sleeve 3, motor housing 12, and fixed base 14 are all installed on the same reference plane of the base 1, thus ensuring that the probe 2, air-bearing sleeve 3, air-bearing guide rail 4, patch motor 7, and laser sensor 14 are installed on the same axis. When the probe 2 is working, the drive foot 10 on the patch motor 7 drives the air-bearing guide rail 4 to move linearly. The air-bearing guide rail 4 drives the probe 2, which is fixed to it, to move, so that the probe 2 contacts the surface to be measured. The relative distance between the air-bearing guide rail 4 and the laser sensor 14 changes. The displacement obtained by the laser sensor 14 through calculation is the feed displacement of the probe 2 relative to the surface to be measured.

[0034] Example 2: Inward pressing hinge type, see reference Figure 7 and Figure 8The air-bearing guide rail 4 has a groove 6 machined in the middle. The groove 6 is fixed to the pre-tightening hinge 11 by screws 13. The two sides of the pre-tightening hinge 11 are respectively interference-fitted with the drive feet 10 of two surface mount motors 7. Two piezoelectric ceramics 9 are installed inside each surface mount motor 7. The surface mount motor 7 is fixed to the inside of the motor housing 12 through the positioning hole 8. The motor housing 12 is installed between two air-bearing sleeves 3 and fixed to the base 1.

[0035] When a sinusoidal current with a phase difference is applied to the piezoelectric ceramic 9, the drive foot 10 of the patch motor 7 can be driven to generate high-frequency elliptical motion. Although the drive foot 10 is interference-fitted with the pre-tightening hinge 11, the pre-tightening hinge 11 can generate elastic deformation after being subjected to force. Therefore, the patch motor 7 drives the pre-tightening hinge 11 to move along the guide rail, and the pre-tightening hinge 11 drives the air-bearing guide rail 4 and the probe 2 to move along the guide rail direction.

[0036] Example 3: Inward compression spring type, refer to Figure 9 Figure 10 The air-bearing guide rail 4 has a groove 6 machined in the middle, and a mounting groove 18 is machined on the groove 6. A spring 17 is installed through the mounting groove 18. The two sides of the spring 17 are respectively interference-fitted with the drive feet 10 of the two surface mount motors 7. Two piezoelectric ceramics 9 are installed inside each surface mount motor 7. The surface mount motor 7 is fixed to the inside of the motor housing 12 through the positioning hole 8. The motor housing 12 is installed between the two air-bearing sleeves 3 and fixed to the base 1.

[0037] When a sinusoidal current with a phase difference is applied to the piezoelectric ceramic 9, the drive foot 10 of the patch motor 7 can be driven to produce a high-frequency elliptical motion. Although the drive foot 10 is interference-fitted with the pre-tightened hinge 11, the spring 17 can produce elastic deformation after being subjected to force. Therefore, the patch motor 7 drives the spring 17 to move along the guide rail direction, and the spring 17 drives the air-bearing guide rail 4 and the probe 2 to move along the guide rail direction.

[0038] The air-bearing guide rail 4 can be driven by an outward support hinge, an inward compression hinge, or an inward compression spring. The probe has active movement and triggering functions, and the probe has active triggering and self-locking functions.

[0039] When actively triggered, the piezoelectric ceramic 9 is energized, and the patch motor 7 drives the air-bearing guide rail 4 and the probe 2 to move linearly. The displacement of the movement is measured by the laser sensor 14 and can be used as the sampling signal of the probe. When the piezoelectric ceramic 9 is not energized, the drive foot 10 is interference-fitted with the pre-tightening hinge 11, and the relative position of the air-bearing guide rail 4 and the laser sensor 14 is fixed. The probe 2 can then be in a locked state, and there is no sampling signal at this time.

[0040] The foregoing has shown and described the basic principles 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. Various changes and modifications can be made to the invention 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 invention is defined by the appended claims and their equivalents.

Claims

1. A miniature air-bearing probe based on a patch motor drive, comprising a base (1) and a probe (2), characterized in that: The base (1) is fixedly connected to two air-bearing sleeves (3). An air-bearing guide rail (4) is installed between the base (1) and the two air-bearing sleeves (3). The air-bearing guide rail (4) can be driven by an outward-supporting hinge. A beam (5) is machined in the middle of the air-bearing guide rail (4). Several bosses (6) are machined on both sides of the beam (5). A patch motor (7) is installed on the boss (6). A positioning hole (8) is machined on the patch motor (7). The positioning hole (8) allows the patch motor (7) to be symmetrically installed on both sides of the beam (5). Two piezoelectric ceramics (9) are installed inside each patch motor (7). The patch motor (7) is machined or installed with... It is equipped with several drive feet (10), the drive feet (10) are interference fit with the inner side of the pre-tightening hinge (11), the upper part of the pre-tightening hinge (11) is fixed to the motor housing (12) by screws (13), the motor housing (12) is installed between two air bearing sleeves (3) and fixed to the base (1), one end of the air bearing guide rail (4) is fixed to the probe (2), and the other side is equipped with a laser sensor (14). The laser sensor (14) is installed on the base (1) through the fixing seat (15), and a sensor housing (16) is installed above the laser sensor (14). The sensor housing (16) is fixed to the base (1). During installation, a gap is left between the air-float sleeve (3) and the air-float guide rail (4), with the gap on one side ranging from 7 to 12 micrometers. During operation, high-pressure gas is introduced through the air-float sleeve (3) and enters the gap. At this time, the air-float guide rail (4) is in a suspended state, and the air-float guide rail (4) and the air-float sleeve (3) do not contact each other and there is no friction. When a sinusoidal current with a phase difference is applied to the piezoelectric ceramic (9), the drive foot (10) of the patch motor (7) can be driven to generate a high-frequency elliptical motion. Although the drive foot (10) is interference-fitted with the pre-tightening hinge (11), the pre-tightening hinge (11) can generate elastic deformation after being subjected to force. Therefore, it drives the patch motor (7) to move along the guide rail, thereby driving the air-float guide rail (4) and the probe (2) to move along the guide rail direction. The air-bearing sleeve (3), motor housing (12) and fixed base (15) are all installed on the same reference plane of the base (1), so it can be ensured that the probe (2), air-bearing sleeve (3), air-bearing guide rail (4), patch motor (7) and laser sensor (14) are installed on the same axis. When the probe (2) is working, the drive foot (10) on the patch motor (7) drives the air-bearing guide rail (4) to move linearly. The air-bearing guide rail (4) drives the probe (2) fixed to it to move, so that the probe (2) contacts the surface to be measured. The relative distance between the air-bearing guide rail (4) and the laser sensor (14) changes. The displacement obtained by the laser sensor (14) through calculation is the feed displacement of the probe (2) relative to the surface to be measured. The probe has active triggering and self-locking functions. When actively triggered, the piezoelectric ceramic (9) is energized, and the patch motor (7) drives the air-bearing guide rail (4) and the probe (2) to move linearly. The displacement of the movement is measured by the laser sensor (14) and can be used as the sampling signal of the probe. When the piezoelectric ceramic (9) is not energized, the drive foot (10) is interference-fitted with the pre-tightening hinge (11), and the relative position of the air-bearing guide rail (4) and the laser sensor (14) is fixed. The probe (2) can then be in a locked state, and there is no sampling signal at this time.

2. The miniature air-bearing probe based on a patch motor drive according to claim 1, characterized in that: The air-bearing guide rail (4) can be driven by an inward pressing hinge. The beam (5) is fixed to the pre-tightening hinge (11) by screws (13). The two sides of the pre-tightening hinge (11) are respectively interference-fitted with the driving feet (10) of two patch motors (7). Two piezoelectric ceramics (9) are installed inside each patch motor (7). The patch motor (7) is fixed to the inside of the motor housing (12) through the positioning hole (8). The motor housing (12) is installed between two air-bearing sleeves (3) and fixed to the base (1). When a sinusoidal current with a phase difference is applied to the piezoelectric ceramic (9), the drive foot (10) of the patch motor (7) can be driven to generate a high-frequency elliptical motion. Although the drive foot (10) is interference-fitted with the pre-tightening hinge (11), the pre-tightening hinge (11) can generate elastic deformation after being subjected to force. Therefore, the patch motor (7) drives the pre-tightening hinge (11) to move along the guide rail, thereby driving the air-bearing guide rail (4) and the probe (2) to move along the guide rail direction.

3. The miniature air-bearing probe based on a patch motor drive according to claim 1, characterized in that: The air-bearing guide rail (4) can be driven by an inward-pressing spring. The beam (5) has a mounting groove (18) and a spring (17) is installed through the mounting groove (18). The two sides of the spring (17) are respectively press-fitted with the driving feet (10) of two patch motors (7). Two piezoelectric ceramics (9) are installed inside each patch motor (7). The patch motor (7) is fixed to the inside of the motor housing (12) through the positioning hole (8). The motor housing (12) is installed between two air-bearing sleeves (3) and fixed to the base (1). When a sinusoidal current with a phase difference is applied to the piezoelectric ceramic (9), the drive foot (10) of the patch motor (7) can be driven to generate a high-frequency elliptical motion. Although the drive foot (10) is interference-fitted with the pre-tightened hinge (11), the spring (17) can generate elastic deformation after being subjected to force. Therefore, the patch motor (7) drives the spring (17) to move along the guide rail direction, and the spring (17) drives the air-bearing guide rail (4) and the probe (2) to move along the guide rail direction.

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