Infrared filter wheel assembly and assembling method thereof

Abstract

The invention belongs to the technical field of infrared imaging equipment, and particularly relates to an infrared filter wheel assembly and an assembling method thereof. Comprising a mounting support, a driving motor, an angular contact bearing assembly, a connecting piece and a light filtering wheel disc, the angular contact bearing assembly is arranged on the mounting support, the end of one side of the connecting piece is inserted into an inner ring of the angular contact bearing assembly to be connected in a matched mode, and the light filtering wheel disc is mounted on the connecting piece; and the driving motor is in transmission coupling with the connecting piece and is used for driving the connecting piece to drive the filtering wheel disc to rotate relative to the mounting bracket. The connecting pieces and the angular contact bearings are introduced to serve as main supports, a traditional structure purely depending on motor shaft supporting is changed, the rigidity of the paired angular contact bearings is large, axial and radial runout of the wheel disc can be effectively limited, deflection is greatly reduced, and the problem of shafting shaking caused by insufficient rigidity of the output shaft of the micro motor is solved.

Description

Technical Field This application belongs to the field of infrared imaging equipment technology, specifically relating to an infrared filter wheel assembly and its assembly method. Background Technology In airborne infrared imaging systems, the filter wheel is a key component for achieving multi-band imaging. Currently, the mainstream filter wheel drive schemes mainly include two types. One is to fix the filter on the inner rotor of a torque motor. Its advantages are high stability and small sway. However, the ring torque motor is heavy, bulky, and occupies a lot of space, which does not conform to the trend of lightweight aerospace equipment. The other is to directly drive the wheel to rotate using a servo motor. Its advantages are light weight and small size. However, the rigidity of the motor output shaft is limited. When directly loading the wheel, it is easy to generate large axial and radial sway, which affects the accuracy and quality of infrared imaging. Therefore, there is an urgent need for a filter wheel assembly that can maintain the advantages of small size and light weight of micro motors while solving the problems of large sway and low accuracy caused by direct drive. Summary of the Invention The purpose of this invention is to provide an infrared filter wheel assembly and its assembly method, which aims to solve the technical problems of existing dual-color filter wheels being large in size and heavy in weight, as well as large sway and low precision caused by direct drive by micro motors.

[0001] This application is achieved through the following technical solution: An infrared filter wheel assembly includes a mounting bracket, a drive motor, an angular contact bearing assembly, a connector, and a filter wheel disk. The angular contact bearing assembly is mounted on the mounting bracket. One end of the connector is inserted into the inner ring of the angular contact bearing assembly for a mating connection. The filter wheel disk is mounted on the connector. The drive motor is coupled to the connector for driving the connector to rotate the filter wheel disk relative to the mounting bracket.

[0002] As described above, an infrared filter wheel assembly includes two angular contact bearings, a bearing retaining sleeve, a bearing pressure plate, and an inner bearing pressure ring. The bearing retaining sleeve is fixedly connected to the mounting bracket. The bearing pressure plate is connected to the bearing retaining sleeve to confine the angular contact bearing within the bearing retaining sleeve. The inner bearing pressure ring is engaged with the connecting member to fasten the angular contact bearing onto the connecting member.

[0003] As described above, in an infrared filter wheel assembly, the filter wheel disk has at least two light-transmitting windows symmetrically opened along the circumference, and a first filter and a second filter are respectively embedded in the two light-transmitting windows. The first filter and the second filter cover different infrared bands and their spectra do not overlap.

[0004] An infrared filter wheel assembly as described above includes a disc frame and a disc retaining ring for holding the first filter and the second filter on the disc frame. The disc surface thickness of the disc frame is thinned to form a recessed disc groove, and the disc groove is provided with reinforcing ribs.

[0005] As described above, an infrared filter wheel assembly has a counterweight mechanism on the filter wheel for dynamic balance adjustment. The counterweight mechanism includes multiple counterweight holes on the filter wheel, each of which is arranged symmetrically along the circumference of the filter wheel and is used for assembling counterweights of different specifications.

[0006] In the infrared filter wheel assembly described above, the connecting member and the filter wheel are interference-fitted and fixed by a locking member.

[0007] As described above, in an infrared filter wheel assembly, the mounting bracket includes a main frame, a mounting frame connected to the top of the main frame, and a support frame disposed within the main frame.

[0008] A method for assembling an infrared filter wheel assembly as described in any of the preceding claims includes the following steps: Step S1: The processed and anodized filter wheel is subjected to heat shaping treatment to eliminate internal stress and ensure the flatness of the wheel; Step S2: Use a filter mounting fixture to install the first filter and the second filter into the light transmission window of the filter wheel, and then cure the adhesive. Step S3: Install the paired angular contact bearing assemblies onto the mounting bracket, adjust the bearing locking force, and install the drive motor onto the mounting bracket; Step S4: Connect and assemble the drive motor, the filter wheel, and the angular contact bearing assembly using connectors, so that the rotation axis of the filter wheel corresponds to the output axis of the drive motor; Step S5: Perform a dynamic balance test on the infrared filter wheel assembly. Based on the test results, add corresponding counterweights to the pre-reserved counterweight holes on the filter wheel until the component's sway meets the preset accuracy requirements.

[0009] In the assembly method described above, in step S3, if the installation clearance of the angular contact bearing assembly does not meet the requirements, copper foil is used to adjust the installation clearance of the bearing to control the locking force.

[0010] In the assembly method described above, in step S5, if the connector does not fit smoothly during assembly, polishing paste is used to grind it to ensure that the connector is perpendicular to the filter wheel and concentric with the bearing assembly.

[0011] Compared with the prior art, this application has the following advantages: 1. By introducing connectors and angular contact bearings as the main support, the traditional structure that relies solely on the motor shaft for support has been changed. The paired angular contact bearings have high rigidity, which can effectively limit the axial and radial runout of the wheel, greatly reduce the wobble, and solve the problem of shaft wobbling caused by insufficient rigidity of the micro motor output shaft.

[0012] 2. A miniature DC brushless motor is used to replace the large torque motor, and the filter wheel is thinned and hollowed out. While ensuring strength, the volume and weight of the components are significantly reduced, the motor load is reduced, and the band switching response speed is improved. At the same time, the reinforcing ribs ensure the structural strength of the disk body, effectively preventing the thin-walled disk body from warping and deforming during processing or operation, thus ensuring imaging quality.

[0013] 3. The filter wheel not only has symmetrical light-transmitting windows along the circumference to ensure the basic symmetry of mass distribution, but also has specially designed counterweight holes for dynamic balance adjustment. This allows the center of gravity offset caused by machining or assembly errors to be corrected by adding or removing counterweight screws or counterweight blocks in the counterweight holes after the assembly is completed, thereby eliminating dynamic imbalance and ensuring that the filter wheel rotates smoothly without vibration at high speed.

[0014] 4. By employing processes such as heating and shaping, tooling-assisted assembly, and dynamic balancing, the problems of easy deformation of thin-walled wheel discs and difficulty in ensuring assembly concentricity have been solved. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a three-dimensional view of the component of this application; Figure 2 yes Figure 1 Exploded view; Figure 3 This is a cross-sectional connection diagram; Figure 4 This is a three-dimensional view of the disk frame in the components of this application; Figure 5 This is a three-dimensional perspective view of the mounting bracket in the component of this application; Figure 6 This is a schematic diagram of the installation of the filter mounting fixture and the filter disc; Figure 7 This is a schematic diagram of the bearing mounting fixture; Figure 8Schematic diagram of bearing mounting fixtures Figure 1 ; Figure 9 Schematic diagram of bearing mounting fixtures Figure 2 ; Figure 10 This is a flowchart of the assembly method of this application. Detailed Implementation To make the technical problems solved by this application, the technical solutions, and the beneficial effects clearer, this application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0016] Please see Figures 1 to 10 An infrared filter wheel assembly includes a mounting bracket 1, a drive motor 2, an angular contact bearing assembly 3, a connector 4, and a filter wheel 5. The angular contact bearing assembly 3 is mounted on the mounting bracket 1. One end of the connector 4 is inserted into the inner ring of the angular contact bearing assembly 3 for connection. The filter wheel 5 is mounted on the connector 4. The drive motor 2 is coupled to the connector 4 for driving the connector 4 to rotate the filter wheel 5 relative to the mounting bracket 1.

[0017] In this embodiment, the drive motor 2 outputs rotational torque and transmits it to the connector 4. Since one end of the connector 4 is inserted into and supported in the inner ring of the angular contact bearing assembly 3 fixed on the mounting bracket 1, the connector 4, as the core transmission hub, drives the filter disc 5 fixed on it to rotate stably around the axis under the precise limiting of the angular contact bearing assembly 3. The beneficial effect of this technical solution is mainly reflected in the fact that the cooperation between the connector 4 and the angular contact bearing assembly 3 constructs a rigid support structure independent of the motor output shaft. Utilizing the excellent radial and axial load bearing capacity of the angular contact bearing assembly 3, it effectively bears the mechanical load and overturning moment when the filter disc 5 rotates, thereby realizing the driving force input. Decoupling from mechanical support eliminates shaft wobble and coaxiality error caused by direct load on the motor shaft, significantly reduces end face runout (low oscillation) of the filter disc 5 during high-speed rotation, greatly improves the alignment accuracy of the infrared light path, and protects the motor shaft from radial force damage, extending the service life of the component. The transmission coupling between the drive motor 2 and the connecting piece 4 can be achieved by spline connection, key connection, or flexible coupling. The connection between the connecting piece 4 and the filter disc 5 can be achieved by bolt fastening, riveting, interference fit, or integral casting. The angular contact bearing assembly 3 can be selected as a pair of back-to-back or face-to-face mounted single-row angular contact ball bearings, or can be replaced with double-row angular contact ball bearings or high-precision crossed roller bearings.

[0018] Furthermore, as a preferred embodiment of this solution and not a limitation, the angular contact bearing assembly 3 includes two angular contact bearings 31, a bearing retaining sleeve 32, a bearing pressure plate 33, and a bearing inner pressure ring 34. The bearing retaining sleeve 32 is fixedly connected to the mounting bracket 1. The bearing pressure plate 33 is connected to the bearing retaining sleeve 32 to confine the angular contact bearing 31 within the bearing retaining sleeve 32. The bearing inner pressure ring 34 is engaged with the connecting member 4 to fasten the angular contact bearing 31 to the connecting member 4.

[0019] In this embodiment, the bearing retaining sleeve 32 is used as a stator support base and fixed on the mounting bracket 1 to accommodate and position the outer rings of two angular contact bearings 31. The outer rings of the angular contact bearings 31 are axially limited by the connection between the bearing pressure plate 33 and the bearing retaining sleeve 32, such as by threaded connection or screw fastening. At the same time, the connecting piece 4 passes through the inner ring of the angular contact bearing 31. The inner ring of the bearing is tightened with the connecting piece 4 by the bearing inner pressure ring 34, such as by threaded locking, so that the inner ring of the angular contact bearing 31 is axially fixed relative to the connecting piece 4, thereby establishing a precise rolling connection between the stator and the rotor. The beneficial effect of this technical solution is that the independent adjustment structure of the bearing pressure plate 33 and the bearing inner pressure ring 34 can conveniently and accurately apply axial preload to the paired angular contact bearings 31, effectively eliminating the internal clearance of the bearing, greatly improving the rigidity and anti-overturning ability of the shaft support, ensuring that the filter disc 5 can maintain extremely high rotational accuracy under high-speed rotation and vibration environment, and the modular design of the bearing retaining sleeve 32 facilitates the independent assembly and maintenance of the components.

[0020] Furthermore, as a preferred embodiment of this solution and not a limitation, the filter wheel 5 is symmetrically provided with at least two light-transmitting windows 55 along its circumference. A first filter 541 and a second filter 542 are respectively embedded in the two light-transmitting windows 55. The first filter 541 and the second filter 542 cover different infrared bands and their spectra do not overlap.

[0021] In this embodiment, as the filter disk 5 rotates under control, the two light-transmitting windows 55 on it alternately enter the optical imaging path, allowing incident light to pass through the first filter 541 and the second filter 542 embedded therein before reaching the detector. This achieves modulation and acquisition of different infrared band light signals in a time sequence. The beneficial effect of this technical solution is that by symmetrically opening the light-transmitting windows 55 along the circumference, the symmetry of the mass distribution of the filter disk 5 is ensured from the structural design source, effectively offsetting part of the rotational centrifugal force, significantly reducing the dynamic imbalance during high-speed rotation and the vibration and sway caused by the shift of the center of mass. By designing filters with non-overlapping spectra that cover different bands (such as mid-wave infrared segments or combinations of mid-wave and long-wave), multi-dimensional spectral detection of target scenes can be achieved, avoiding signal crosstalk and significantly improving the target recognition rate and anti-interference capability of the imaging system in complex environments. The bands of the first filter 541 and the second filter 542 can be replaced with any combination of short-wave infrared, long-wave infrared, or visible light bands. The filters can be fixed in the window by UV adhesive bonding, mechanical pressure ring locking, or elastic spring limiting. The first filter corresponds to band ap (full band, first stage: 3.7um-5um, second stage: 3.4um-4.8um), and the second filter corresponds to band pb (mid-wave band, first stage: 4.4um-5um, second stage: 4.4um-4.8um). The two together cover the entire mid-wave infrared band ab, but there is no spectral overlap.

[0022] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the filter wheel 5 includes a wheel frame 51 and a wheel retaining ring 52 for holding the first filter 541 and the second filter 542 on the wheel frame 51. The thickness of the wheel surface of the wheel frame 51 is reduced to form a sunken wheel groove 53, and the wheel groove 53 is provided with reinforcing ribs 54.

[0023] In this embodiment, the disc body pressure ring 52 is used as a mechanical fastening element. Screws or glue are used to press and limit the first filter 541 and the second filter 542 within the mounting groove of the disc body frame 51, achieving reliable fixing and quick assembly / disassembly of the filters. Simultaneously, material in non-critical stress areas on the disc surface of the disc body frame 51 is removed through precision CNC machining or mold casting, forming a large-area sunken disc groove 53. Solid material is retained only in the radial direction or along the force transmission path to form reinforcing ribs 54. This reduces the mass and rotational inertia of the filter disc 5, lowers the starting and braking load on the drive motor 2, and improves the response during band switching. While maintaining high speed, the reinforcing ribs 54 greatly improve the bending section modulus and structural rigidity of the disc, effectively suppressing the warping deformation that may occur in the thin-walled disc under high-speed rotation centrifugal force, thermal expansion and contraction or processing residual stress, ensuring the flatness and perpendicularity of the filter to the optical axis in dynamic environments. The distribution of the reinforcing ribs 54 can be designed as radial, concentric, honeycomb grid or triangular truss structure according to the finite element analysis results. The material of the disc frame 51 can be selected from high specific strength materials such as magnesium-lithium alloy, carbon fiber composite material or titanium alloy to further achieve extreme lightweighting.

[0024] Furthermore, as a preferred embodiment of this solution and not a limitation, the filter wheel 5 is provided with a counterweight mechanism 53 for dynamic balance adjustment. The counterweight mechanism 53 includes a plurality of counterweight holes 531 opened on the filter wheel 5. Each of the counterweight holes 531 is arranged along the circumferential direction of the filter wheel 5 and is symmetrically distributed. The counterweight holes 531 are for assembling counterweights of different specifications.

[0025] In this embodiment, pre-drilled counterweight holes 531 symmetrically distributed along the circumference are used as mass compensation reference points for dynamic balance adjustment. After the filter wheel 5 is manufactured and assembled, the magnitude and phase angle of the imbalance during the rotation of the wheel are detected by a dynamic balance tester. Based on this, counterweights of different mass specifications, such as set screws of different lengths, metal plugs or shims of different densities, are selected and installed into the corresponding counterweight holes 531 to compensate for the centrifugal force vector and counteract the inherent eccentric mass torque of the wheel, forcibly correcting the center of mass of the filter wheel 5 to its rotation axis. The beneficial effect of this technical solution is that it provides a standardized, quantifiable and non-destructive dynamic balance correction method, and the use of pre-drilled holes and standard counterweights avoids the need for further adjustments to the filter wheel. The risk of secondary cutting damage or adhesive aging and detachment of the optical disc 5 body structure can be flexibly compensated for the asymmetrical mass distribution caused by uneven material density, processing tolerance, differences in surface coating thickness, or filter installation errors. This ensures that the component maintains extremely low vibration amplitude and shaft dynamic load when switching bands at high speed, thereby guaranteeing the clarity of infrared imaging and the long-term operational reliability of the system. The counterweight hole 531 can be designed as an internal thread hole to be used with set screws of different lengths for fine adjustment, or it can be designed as an optical hole to be used with an interference-pressed pin or rivet. The number of counterweight holes 531 can be set to three, four or more evenly distributed according to the disc diameter. The material of the counterweight can be selected from copper or tungsten alloys with higher specific gravity to reduce volume.

[0026] Furthermore, as a preferred embodiment of this solution and not a limitation, the connector 4 and the filter wheel 5 are interference-fitted and fixed by a locking member.

[0027] In this embodiment, by utilizing the dimensional tolerance design that the outer diameter of the connector 4 is slightly larger than the inner diameter of the center mounting hole of the filter disc 5, an interference fit is achieved through press-fitting or temperature difference assembly processes. This generates enormous radial pressure and static friction between the contact surfaces of the two components, thereby completely eliminating the fit clearance and reliably transmitting rotational torque without the need for keyway assistance. Simultaneously, locking components such as nuts, screws, or glands apply a sustained clamping force in the axial direction, firmly securing the filter disc 5 to the shoulder or positioning end face of the connector 4. On the one hand, the zero-clearance characteristic of the interference fit completely eliminates the traditional clearance fit. The radial play and backlash that may exist in the keyed connection ensure extremely high coaxiality and perpendicularity between the filter wheel 5 and the rotation axis, fundamentally suppressing radial runout and end face sway during high-speed rotation. On the other hand, under the high-frequency vibration or impact conditions commonly encountered in airborne equipment, the locking component provides additional axial anti-disengagement safety redundancy, preventing connection failure caused by fretting wear of the interference surface, and significantly improving the overall structural rigidity and operational reliability of the component. The locking component can specifically be a self-locking nut with nylon insert, a slotted nut with cotter pin, or an end face pressure plate with anti-loosening bolt.

[0028] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the mounting bracket 1 includes a main frame 11, a mounting frame 12 connected to the top of the main frame 11, and a support frame 13 disposed within the main frame 11.

[0029] In this embodiment, the main frame 11 serves as the external basic skeleton of the component, providing overall rigidity and protective space. The top-connected mounting frame 12 acts as a standardized mechanical interface for precisely suspending or fixing the entire filter wheel assembly to the optical base of the infrared imaging system. The support frame 13 located inside the main frame 11 is specifically designed as a direct bearing for the drive motor 2 and the angular contact bearing assembly 3. This prevents the stress deformation of the housing generated when the external mounting screws are tightened from being directly transmitted to the precision bearing and motor mating points inside, effectively isolating the interference of external mounting stress on the coaxiality of the internal shaft system and ensuring the geometric accuracy of the filter wheel 5 during long-term operation. At the same time, the local stiffness reinforcement design of the support frame 13 for the core stress area can effectively resist the resonance caused by high-speed rotation. The main frame 11, mounting frame 12, and support frame 13 can be integrally machined from aerospace aluminum alloy using CNC machining to achieve the highest structural strength and the lowest cumulative tolerance.

[0030] A method for assembling an infrared filter wheel assembly as described in any of the preceding claims includes the following steps: Step S1: The processed and anodized filter wheel 5 is subjected to heat shaping treatment to eliminate internal stress and ensure the flatness of the wheel; Step S2: Use the filter mounting fixture 6 to install the first filter 541 and the second filter 542 into the light transmission window 55 of the filter wheel 5, and then cure the glue. Step S3: Install the paired angular contact bearing assemblies 3 onto the mounting bracket 1, adjust the bearing locking force, and install the drive motor 2 onto the mounting bracket 1; Step S4: Connect and assemble the drive motor 2, the filter wheel 5 and the angular contact bearing assembly 3 through the connector 4, so that the rotation axis of the filter wheel 5 corresponds to the output axis of the drive motor 2; Step S5: Perform a dynamic balance test on the infrared filter wheel assembly. Based on the test results, add corresponding counterweights to the counterweight holes 531 reserved in the filter wheel disk 5 until the component's sway meets the preset accuracy requirements.

[0031] In this embodiment, firstly, in step S1, the internal stress of the filter disc 5 caused by its thin-walled structure and anodized surface treatment is forcibly released through heating and shaping treatment at a specific temperature curve, physically correcting the plane warping. Then, in step S2, the positioning reference of a special tooling is used to ensure the perpendicularity of the optical axes of the first filter 541 and the second filter 542 and to solidify and lock them. In steps S3 and S4, with the connector 4 as the core hub, a high-rigidity rotational reference independent of the motor shaft is established by step-by-step installation and adjustment of the preload of the angular contact bearing assembly 3. Finally, in step S5, quality compensation is performed based on the dynamic balance feedback under the rotational state of the entire machine. The beneficial effect of this technical solution is that it systematically solves a series of precision problems from part processing deformation to assembly error accumulation throughout the entire process. In particular, the heating and shaping process effectively solves the industry pain point of easy deformation of lightweight aluminum alloy discs leading to blurred imaging. Combined with tooling-assisted assembly and end-of-line dynamic balancing correction, it significantly improves the finished product yield, batch consistency, and stability during high-speed operation of the components, and prevents shaft jamming or vibration caused by improper assembly. In other possible embodiments, the heating and shaping in step S1 can be replaced by vibration aging or deep cryogenic treatment to eliminate stress. The glue curing in step S2 can be replaced by UV light curing or mechanical fixing with pressure rings. The adjustment of bearing locking force in step S3 can be quantitatively controlled by using a torque wrench or measuring the starting friction torque. The counterweight adjustment in step S5 can also be achieved by drilling holes in the non-counterweight area on the back of the disc to remove weight, or by using a laser automatic weight removal and balancing machine for automated correction.

[0032] Furthermore, as a preferred embodiment of this solution and not a limitation, in step S3, if the installation clearance of the angular contact bearing assembly 3 does not meet the requirements, copper foil is used to adjust the installation clearance of the bearing to control the locking force.

[0033] In this embodiment, copper foil, with its excellent ductility, uniform thickness, and multiple specifications, is used as a precision compensation shim. It is placed between the outer ring end face of the angular contact bearing assembly 3 and the bearing pressure plate, or in the fit clearance between the bearing seat hole and the bearing outer ring. By physically filling the gap, the cumulative dimensional tolerances generated during component processing and assembly are corrected. This allows for precise control of the axial preload or radial fit tightness applied to the bearing when tightening the locking accessories. The beneficial effects of this technical solution are that it provides a low-cost and highly flexible on-site assembly fine-tuning method, effectively solving the problem of excessive clearance or looseness of the bearing after installation due to limitations in machining accuracy. This ensures that the angular contact bearing assembly 3 can work under optimal preload, guaranteeing both support rigidity and maintaining minimum frictional torque, and significantly improving the start-up response characteristics and rotational stability of the infrared filter wheel assembly.

[0034] Furthermore, as a preferred embodiment of this solution and not a limitation, in step S5, if the connector 4 does not fit smoothly during assembly, polishing paste is used to grind it to ensure that the connector 4 is perpendicular to the filter wheel 5 and concentric with the bearing assembly.

[0035] In this embodiment, fine, high-hardness abrasive particles suspended in the polishing paste, such as silicon carbide or alumina powder, are used as cutting media. These particles are applied between the mating surfaces of the connector 4 and the filter disc 5. Through relative rotation and axial reciprocating motion, the microscopic high points, machining marks, and burrs on the contact surfaces are precisely micro-cut and smoothed. The beneficial effect of this technical solution lies in the fact that this manual or semi-automatic mating process can, at low cost, correct roundness errors, cylindricity errors, and coaxiality deviations left over from machining processes. This achieves extremely high contact rates and almost zero geometric interference between the mating surfaces, ensuring that the filter disc 5 is strictly perpendicular to the rotation axis of the connector 4 after installation, and guaranteeing the high concentricity of the connector 4 and the bearing assembly. This eliminates elastic deformation caused by installation tilt or forced pressing due to uneven mating surfaces, ensuring low sway characteristics of the component from the assembly source.

[0036] The working principle of this embodiment is as follows: When the system is powered on, the output shaft of the drive motor 2 immediately begins to rotate and output torque. This torque is transmitted to the connector 4 through a key connection or interference fit, driving the connector 4 to rotate around its axis. During this process, since one end of the connector 4 is precisely fitted and supported in the inner ring of the angular contact bearing assembly 3 fixed on the mounting bracket 1, the angular contact bearing assembly 3, with its high-rigidity rolling friction structure, bears all the radial load and axial overturning moment generated by the connector 4 and the filter wheel 5, thereby forcibly limiting the movement trajectory of the rotating parts. The filter wheel 5, fixed to the other end of the connector 4, rotates synchronously. The high-speed rotation drives the first filter 541 and the second filter 542, which are embedded in the light-transmitting window 55, to alternately enter the optical path of the infrared imaging system at a predetermined frequency, thereby realizing time-division modulation of the radiation signals of different infrared bands of the target scene. At the same time, the reinforcing ribs 54 on the surface of the filter wheel 5 effectively resist the deformation of centrifugal force generated by high-speed rotation. Together with the counterweights pre-adjusted in the counterweight hole 531, they dynamically offset the vibration caused by the center of mass shift, ensuring that the filters always maintain perpendicularity to the optical axis and extremely low end face runout during high-speed switching, thus achieving high-precision dual-color imaging switching.

[0037] The above are implementation methods provided in conjunction with specific content, and it is not intended that the specific implementation of this application is limited to these descriptions. Any methods or structures that are similar to those of this application, or any technical deductions or substitutions made based on the concept of this application, should be considered within the scope of protection of this application.

Claims

1. An infrared filter wheel assembly, characterized in that, The device includes a mounting bracket (1), a drive motor (2), an angular contact bearing assembly (3), a connector (4), and a filter disc (5). The angular contact bearing assembly (3) is mounted on the mounting bracket (1). One end of the connector (4) is inserted into the inner ring of the angular contact bearing assembly (3) for connection. The filter disc (5) is mounted on the connector (4). The drive motor (2) is coupled to the connector (4) for driving the connector (4) to rotate the filter disc (5) relative to the mounting bracket (1).

2. The infrared filter wheel assembly according to claim 1, characterized in that, The angular contact bearing assembly (3) includes two angular contact bearings (31), a bearing retaining sleeve (32), a bearing pressure plate (33), and a bearing inner pressure ring (34). The bearing retaining sleeve (32) is fixedly connected to the mounting bracket (1). The bearing pressure plate (33) is connected to the bearing retaining sleeve (32) to confine the angular contact bearing (31) inside the bearing retaining sleeve (32). The bearing inner pressure ring (34) is connected to the connecting member (4) to fasten the angular contact bearing (31) to the connecting member (4).

3. The infrared filter wheel assembly according to claim 1, characterized in that, The filter wheel (5) has at least two light-transmitting windows (55) symmetrically opened along the circumference. A first filter (541) and a second filter (542) are respectively embedded in the two light-transmitting windows (55). The first filter (541) and the second filter (542) cover different infrared bands and their spectra do not overlap.

4. An infrared filter wheel assembly according to claim 3, characterized in that, The filter wheel (5) includes a disc frame (51) and a disc retaining ring (52) for holding the first filter (541) and the second filter (542) on the disc frame (51). The disc surface thickness of the disc frame (51) is thinned to form a sunken disc groove (53), and the disc groove (53) is provided with reinforcing ribs (54).

5. An infrared filter wheel assembly according to claim 1, characterized in that, The filter wheel (5) is provided with a counterweight mechanism (53) for dynamic balance adjustment. The counterweight mechanism (53) includes a plurality of counterweight holes (531) opened on the filter wheel (5). Each of the counterweight holes (531) is arranged along the circumferential direction of the filter wheel (5) and is symmetrically distributed. The counterweight holes (531) are for the assembly of counterweights of different specifications.

6. An infrared filter wheel assembly according to claim 1, characterized in that, The connector (4) and the filter wheel (5) are interference fit and are fixed by a locking member.

7. An infrared filter wheel assembly according to claim 1, characterized in that, The mounting bracket (1) includes a main frame (11), a mounting frame (12) connected to the top of the main frame (11), and a support frame (13) disposed within the main frame (11).

8. A method for assembling an infrared filter wheel assembly as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step S1: The processed and anodized filter wheel (5) is subjected to heat shaping treatment to eliminate internal stress and ensure the flatness of the wheel; Step S2: Use the filter mounting fixture (6) to install the first filter (541) and the second filter (542) into the light-transmitting window (55) of the filter wheel (5) and cure the glue. Step S3: Use the bearing mounting fixture (7) to install the pair of angular contact bearing assemblies (3) onto the mounting bracket (1), adjust the bearing locking force, and install the drive motor (2) onto the mounting bracket (1); Step S4: Connect and assemble the drive motor (2), the filter wheel (5) and the angular contact bearing assembly (3) through the connector (4) so ​​that the rotation axis of the filter wheel (5) corresponds to the output axis of the drive motor (2); Step S5: Perform a dynamic balance test on the infrared filter wheel assembly. Based on the test results, install the corresponding counterweight in the counterweight hole (531) reserved in the filter wheel disk (5) until the component deflection meets the preset accuracy requirements.

9. The assembly method according to claim 8, characterized in that, In step S3, if the installation clearance of the angular contact bearing assembly (3) does not meet the requirements, copper foil is used to adjust the installation clearance of the bearing to control the locking force.

10. The assembly method according to claim 8, characterized in that, In step S5, if the connector (4) does not fit smoothly during assembly, polishing paste is used to grind it to ensure that the connector (4) is perpendicular to the filter wheel (5) and concentric with the bearing assembly.

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