An automatic adjustment mechanism for coaxial diaphragm aperture

Abstract

An automatic adjustment mechanism for a coaxial iris aperture, belonging to the field of photoelectric spherical infrared cameras, comprises an iris gland, an inner bearing pressure ring, a cross-roll bearing, an outer bearing pressure ring, a motor adapter, a main support flange, a DC servo motor, an imaging lens assembly, a drive gear, a driven gear, a lever-type variable iris, two photoelectric switch baffles, a lever retaining seat, two photoelectric switches, an iris lever, and two baffle mounting seats. The driven gear center hole size is matched to the outer diameter size of the lever-type variable iris, ensuring maximum mechanical error-free installation between the driven gear center hole and the lever-type variable iris. The high-precision cross-roll bearing can withstand axial and radial forces, ensuring that the lever-type variable iris aperture remains coaxial with the main optical axis of the imaging lens assembly during aperture changes without introducing mechanical errors. A mechanical hard limiter is designed to protect the lever-type variable iris from damage.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric ball table infrared cameras, and in particular relates to an automatic adjustment mechanism for a co-optical axis diaphragm aperture. Background Art

[0002] In recent years, photoelectric infrared cameras have seen rapid development, particularly in areas such as forestry and border defense. In natural environments like these, sunlight intensity varies from morning to afternoon and evening, causing variations in the radiant energy of objects. Infrared cameras must adjust the amount of light entering the lens based on the intensity of this ambient radiation. Otherwise, the energy received by the detector's focal plane will be too strong, causing oversaturation of the detector's grayscale values. Therefore, a motorized variable aperture (Iris) must be incorporated into the lens, and its aperture must be coaxial with the optical axis of the optical system. By using information such as the image's grayscale value to adjust the aperture, the Iris's aperture is adjusted, thereby controlling the amount of light entering the lens and achieving a clear image.

[0003] At present, most of the electric variable apertures on the market are modular products, which are only suitable for laboratory environments. The mechanical interface is connected to the lens optical system, and it is difficult to ensure that the center hole of the aperture is coaxial with the optical axis of the optical system. In addition, dark corners will appear in the image during use. Even if the center hole of the aperture is coaxial with the optical axis of the optical system through complex installation and adjustment methods, it will consume a lot of manpower and material resources. Moreover, in the long-term use process in the future, as the ambient temperature affects it, the center hole of the aperture will gradually shift, which will not meet the requirements of the optical system. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the existing electric variable iris, the present invention provides an automatic adjustment mechanism for the aperture of a coaxial iris.

[0005] The technical solutions adopted by the present invention to solve the technical problems are as follows:

[0006] The present invention provides an automatic adjustment mechanism for a coaxial diaphragm aperture, comprising: a main support flange;

[0007] a DC servo motor and an imaging lens assembly mounted on the rear surface of the main support flange;

[0008] A driving gear, a driven gear, and a lever holder are mounted on the front surface of the main support flange; the driving gear is sleeved on the main shaft of the DC servo motor, and the driving gear, the driven gear, and the lever holder are arranged in order from top to bottom; the driving gear and the driven gear are meshed with each other;

[0009] A lever-type variable aperture iris installed in the center hole of the driven gear;

[0010] An iris gland installed on the edge of the center hole of the driven gear; the inner wall of the iris gland presses the lever-type variable iris;

[0011] A first photoelectric switch blocking piece and a second photoelectric switch blocking piece are symmetrically mounted on the edge of the surface of the driven gear; the first photoelectric switch blocking piece and the second photoelectric switch blocking piece are symmetrically arranged on both sides of the aperture gland;

[0012] A cross roller bearing mounted on the rear end of the driven gear;

[0013] A bearing inner pressure ring is mounted on the outer ring of the crossed roller bearing; the inner ring of the bearing inner pressure ring matches the outer ring of the crossed roller bearing;

[0014] A bearing outer pressure ring connected to the rear end of the driven gear; the inner side wall of the bearing outer pressure ring cooperates with the rear side wall of the cross rolling bearing;

[0015] A first photoelectric switch and a second photoelectric switch are symmetrically mounted on both sides of the lever holder; the first photoelectric switch and the second photoelectric switch are respectively connected to a DC servo motor;

[0016] An iris shifting rod is installed on the upper end of the shifting rod holding seat; the iris shifting rod is inserted into the groove on the outer side wall of the shifting rod type variable iris.

[0017] Furthermore, the first photoelectric switch blocking piece and the second photoelectric switch blocking piece are both machined with long slots. When the first photoelectric switch blocking piece and the second photoelectric switch blocking piece rotate counterclockwise with the driven gear, the first photoelectric switch blocking piece is inserted into the first photoelectric switch, and the extreme value size of the change in the diameter of the lever-type variable aperture is adjusted by slightly adjusting the position of the first photoelectric switch blocking the first photoelectric switch. When the first photoelectric switch blocking piece blocks the first photoelectric switch, a signal is generated and fed back to the DC servo motor, and the DC servo motor stops working, thereby achieving electronic limiting of the change in the diameter of the lever-type variable aperture to the extreme position. When the first photoelectric switch blocking piece and the second photoelectric switch blocking piece rotate clockwise with the driven gear, the second photoelectric switch blocking piece is inserted into the second photoelectric switch. When the second photoelectric switch blocking piece blocks the second photoelectric switch, a signal is generated and fed back to the DC servo motor, and the DC servo motor stops working, thereby achieving electronic limiting of the change in the diameter of the lever-type variable aperture to the extreme position.

[0018] Furthermore, when the first photoelectric switch is accidentally damaged and the electronic limit cannot be completed, causing the DC servo motor to be unable to stop working, the mechanical hard limit formed between the side surface of the iris pressure cover and the left side surface of the upper end of the lever retaining seat blocks the rotation of the driven gear, thereby protecting the lever-type variable iris from damage; when the second photoelectric switch is accidentally damaged and the electronic limit cannot be completed, causing the DC servo motor to be unable to stop working, the mechanical hard limit formed between the side surface of the iris pressure cover and the right side surface of the upper end of the lever retaining seat blocks the rotation of the driven gear, thereby protecting the lever-type variable iris from damage.

[0019] Furthermore, the iris cover is an arc-shaped structure, and the opening at the lower end of the iris cover is aligned with the iris lever.

[0020] Furthermore, it also includes a motor adapter installed on the rear surface of the main support flange, and the DC servo motor is installed on the motor adapter.

[0021] Furthermore, a DC servo motor encoder is installed on the DC servo motor.

[0022] Furthermore, it also includes a first baffle mounting seat and a second baffle mounting seat symmetrically installed on the edge of the surface of the driven gear, and the first baffle mounting seat and the second baffle mounting seat are symmetrically arranged on the left and right sides of the aperture cover; the first photoelectric switch baffle and the second photoelectric switch baffle are respectively installed on the outer ends of the first baffle mounting seat and the second baffle mounting seat.

[0023] Furthermore, the first photoelectric switch blocking piece and the second photoelectric switch blocking piece have the same structural dimensions.

[0024] The beneficial effects of the present invention are:

[0025] The present invention provides an automatic coaxial iris aperture adjustment mechanism suitable for use as the main support structure of a lens. The lenses in the imaging lens assembly are then mounted in conjunction with the mechanism, mechanically ensuring maximum coaxiality of the entire optical axis. The lever-type variable iris features high aperture change accuracy and low cost. The center hole size of the driven gear matches the outer diameter of the lever-type variable iris, ensuring maximum mechanical error-free installation between the center hole of the driven gear and the lever-type variable iris. The driven gear also exhibits vibration and impact resistance. High-precision cross-roll bearings are used, capable of withstanding axial and radial forces, ensuring a rotational runout accuracy of 0.005 mm. This ensures that the lever-type variable iris aperture remains coaxial with the main optical axis of the imaging lens assembly during aperture changes, preventing mechanical errors from being introduced during shaft rotation. A mechanical hard limiter is incorporated into the present invention to protect the lever-type variable iris from damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1The figure is a schematic structural diagram of an automatic adjustment mechanism for a coaxial diaphragm aperture according to the present invention.

[0027] Figure 2 The figure is a schematic structural diagram of an automatic adjustment mechanism for a coaxial diaphragm aperture according to the present invention.

[0028] Figure 3 This is a front view of an automatic adjustment mechanism for a coaxial diaphragm aperture according to the present invention.

[0029] Figure 4 for Figure 3 AA cross-section shown.

[0030] Figure 5 This is a schematic diagram of the mechanical hard limit position.

[0031] In the figure, 1. aperture cover, 2. bearing inner pressure ring, 3. cross roller bearing, 4. bearing outer pressure ring, 5. motor adapter, 6. main support flange, 7. DC servo motor, 8. imaging lens group, 9. driving gear, 10. driven gear, 11. lever-type variable aperture, 12. first photoelectric switch baffle, 13. lever holding seat, 14. first photoelectric switch, 15. aperture lever, 16. first baffle mounting seat, 17. second photoelectric switch baffle, 18. second baffle mounting seat, 19. second photoelectric switch, C, mechanical hard limit position. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below with reference to the accompanying drawings.

[0033] like Figures 1 to 4 As shown, the present invention is suitable for a coaxial diaphragm aperture automatic adjustment mechanism, which mainly includes: an diaphragm cover 1, a bearing inner pressure ring 2, a cross roller bearing 3, a bearing outer pressure ring 4, a motor adapter 5, a main support flange 6, a DC servo motor 7, an imaging lens group 8, a driving gear 9, a driven gear 10, a lever-type variable diaphragm 11, a first photoelectric switch baffle 12, a lever holding seat 13, a first photoelectric switch 14, an diaphragm lever 15, a first baffle mounting seat 16, a second photoelectric switch baffle 17, a second baffle mounting seat 18, a second photoelectric switch 19 and a DC servo motor encoder.

[0034] The imaging lens group 8 is mounted on the center of the rear surface of the main support flange 6; the motor adapter 5 is mounted on the upper end of the rear surface of the main support flange 6, the DC servo motor 7 is mounted on the motor adapter 5, and the DC servo motor 7 is connected to the main support flange 6 through the motor adapter 5; a DC servo motor encoder is mounted on the DC servo motor 7; a driving gear 9 is mounted on the upper end of the front surface of the main support flange 6, and the driving gear 9 is sleeved on the main shaft of the DC servo motor 7, and the driving gear 9 is driven to rotate by the main shaft of the DC servo motor 7; the driven gear 10 is mounted on the main support flange 6. At the center of the front surface of the support flange 6, the driving gear 9 and the driven gear 10 are meshed with each other; the lever-type variable aperture 11 is installed in the center hole of the driven gear 10, and the central axis of the lever-type variable aperture 11 coincides with the main optical axis of the imaging lens group 8; the iris gland 1 is designed as an arc structure as a whole, and the iris gland 1 is installed at the edge of the center hole of the driven gear 10 by bolts. At the same time, the opening of the iris gland 1 is set directly downward, that is, the opening of the iris gland 1 is aligned with the iris lever 15, and the lever-type variable aperture 11 is pressed tightly by the inner wall of the iris gland 1; the first baffle is installed The seat 16 and the second baffle mounting seat 18 are symmetrically mounted on the edge of the surface of the driven gear 10, and the first baffle mounting seat 16 and the second baffle mounting seat 18 are symmetrically arranged on the left and right sides of the aperture gland 1; the first photoelectric switch baffle 12 is mounted on the outer end of the first baffle mounting seat 16, and the second photoelectric switch baffle 17 is mounted on the outer end of the second baffle mounting seat 18, and the first photoelectric switch baffle 12 and the second photoelectric switch baffle 17 are symmetrically arranged; the structural dimensions of the first photoelectric switch baffle 12 and the second photoelectric switch baffle 17 are the same, and the first photoelectric switch baffle 12 and the second photoelectric switch baffle 17 are symmetrical. A photoelectric switch cover 12 and a second photoelectric switch cover 17 are both machined with long slots; a lever holder 13 is mounted on the lower end of the front surface of the main support flange 6, and the lever holder 13 is located directly below the driven gear 10; an iris lever 15 is mounted on the upper end of the lever holder 13, and the iris lever 15 is inserted into the groove on the outer wall of the lever-type variable iris 11; a first photoelectric switch 14 and a second photoelectric switch 19 are symmetrically mounted on the left and right sides of the lever holder 13, and the first photoelectric switch 14 and the second photoelectric switch 19 are respectively connected to the DC servo motor 7; Figure 4 As shown, the inner ring of the cross roller bearing 3 is mounted on the rear end of the driven gear 10, the inner pressure ring 2 of the bearing is mounted on the outer ring of the cross roller bearing 3, the inner ring of the inner pressure ring 2 of the bearing matches the outer ring of the cross roller bearing 3, the outer pressure ring 4 of the bearing is connected to the rear end of the driven gear 10, and the inner side wall of the outer pressure ring 4 of the bearing matches the rear side wall of the cross roller bearing 3.

[0035] The present invention adopts a coaxial diaphragm automatic adjustment mechanism as the main support structure of the lens, and the lenses in the imaging lens group 8 are then installed in conjunction with it, thereby ensuring the coaxiality accuracy of the entire optical axis to the greatest extent from a mechanical perspective.

[0036] In this embodiment, a lever-type variable aperture 11, which is a mature product on the shelf, is used. It has the characteristics of high aperture change accuracy and low cost. The center hole size of the driven gear 10 is matched with the outer diameter size of the lever-type variable aperture 11, which maximizes the mechanical matching error between the center hole of the driven gear 10 and the lever-type variable aperture 11 during installation. At the same time, the driven gear 10 has the characteristics of resistance to vibration and impact.

[0037] In this embodiment, the aperture lever 15 is clamped and held stationary by the lever holding seat 13. When the lever-type variable aperture 11 rotates along with the driven gear 10, the aperture lever 15 and the lever-type variable aperture 11 achieve relative movement, thereby realizing the electric control change of the aperture of the lever-type variable aperture 11.

[0038] In this embodiment, the driving part is mainly composed of a gear pair and a DC servo motor 7. The driving gear 9 is driven by the main shaft of the DC servo motor 7 to rotate forward or reverse, and the lever-type variable aperture 11 rotates around the main optical axis of the imaging lens group 8 along with the driven gear 10.

[0039] In this embodiment, the main body of the lever-type variable aperture 11 is installed in the shaft system of the driven gear 10. The two are precisely machined using a shaft-hole fit. The cross-roller bearing 3 uses a high-precision cross-roller bearing that can withstand axial and radial forces, ensuring that the shaft system rotational runout accuracy is 0.005 mm, which is far less than the optical precision error index. Therefore, the lever-type variable aperture 11 can always maintain the required coaxiality with the main optical axis of the imaging lens group 8 during the aperture change process, so that no mechanical error is introduced during the rotation of the shaft system.

[0040] In this embodiment, the DC servo motor encoder is installed on the DC servo motor 7. The DC servo motor encoder uses a 4096-bit incremental encoder, which can increase the aperture change resolution of the lever-type variable aperture 11 and meet the aperture fine-motion change requirements of the lever-type variable aperture 11.

[0041] In this embodiment, the driving gear 9 is fixedly connected to the main shaft of the DC servo motor 7. The rotation of the main shaft of the DC servo motor 7 drives the driven gear 10 to rotate, thereby achieving controllable change in the aperture size of the lever-type variable iris 11.

[0042] like Figure 5As shown, the first photoelectric switch blocking piece 12 and the second photoelectric switch blocking piece 17 are both machined with long slots. When the first photoelectric switch blocking piece 12 and the second photoelectric switch blocking piece 17 rotate counterclockwise with the driven gear 10, the first photoelectric switch blocking piece 12 is inserted into the first photoelectric switch 14, and the position of the first photoelectric switch blocking piece 12 covering the first photoelectric switch 14 can be slightly adjusted, thereby accurately adjusting the extreme value size of the diameter change of the lever-type variable aperture 11. When the first photoelectric switch blocking piece 12 covers the first photoelectric switch 14, a signal is generated and fed back to the DC servo motor 7, and the DC servo motor 7 stops working, thereby achieving the control of the lever-type variable aperture 11. The electronic limit of the aperture change to the extreme position; similarly, when the first photoelectric switch block 12 and the second photoelectric switch block 17 rotate clockwise with the driven gear 10, the second photoelectric switch block 17 is inserted into the second photoelectric switch 19, and the position of the second photoelectric switch block 17 blocking the second photoelectric switch 19 can be slightly adjusted, thereby accurately adjusting the extreme size of the aperture change of the lever-type variable aperture 11. The second photoelectric switch block 17 blocks the second photoelectric switch 19 to generate a signal feedback to the DC servo motor 7, and the DC servo motor 7 stops working, thereby realizing the electronic limit of the aperture change of the lever-type variable aperture 11 to the extreme position. In addition, when the first photoelectric switch 14 is accidentally damaged and the electronic limit cannot be completed, causing the DC servo motor 7 to be unable to stop working, the mechanical hard limit formed between the side of the iris cover 1 and the left side of the upper end of the lever retaining seat 13 can be used to block the rotation of the driven gear 10, thereby protecting the lever-type variable iris 11 from damage; similarly, when the second photoelectric switch 19 is accidentally damaged and the electronic limit cannot be completed, causing the DC servo motor 7 to be unable to stop working, the mechanical hard limit formed between the side of the iris cover 1 and the right side of the upper end of the lever retaining seat 13 can be used to block the rotation of the driven gear 10, thereby protecting the lever-type variable iris 11 from damage.

[0043] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the protection content of the present invention.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An automatic adjustment mechanism for a coaxial diaphragm aperture, comprising: The main support flange is characterized by further comprising: a DC servo motor and an imaging lens assembly mounted on the rear surface of the main support flange; A driving gear, a driven gear, and a lever holder are mounted on the front surface of the main support flange; the driving gear is sleeved on the main shaft of the DC servo motor, and the driving gear, the driven gear, and the lever holder are arranged in order from top to bottom; the driving gear and the driven gear are meshed with each other; A lever-type variable aperture iris installed in the center hole of the driven gear; An iris gland installed on the edge of the center hole of the driven gear; the inner wall of the iris gland presses the lever-type variable iris; A first photoelectric switch blocking piece and a second photoelectric switch blocking piece are symmetrically mounted on the edge of the surface of the driven gear; the first photoelectric switch blocking piece and the second photoelectric switch blocking piece are symmetrically arranged on both sides of the aperture gland; A cross roller bearing mounted on the rear end of the driven gear; A bearing inner pressure ring is mounted on the outer ring of the crossed roller bearing; the inner ring of the bearing inner pressure ring matches the outer ring of the crossed roller bearing; A bearing outer pressure ring connected to the rear end of the driven gear; the inner side wall of the bearing outer pressure ring cooperates with the rear side wall of the cross rolling bearing; A first photoelectric switch and a second photoelectric switch are symmetrically mounted on both sides of the lever holder; the first photoelectric switch and the second photoelectric switch are respectively connected to a DC servo motor; An iris lever is mounted on the upper end of the lever holder; the iris lever is inserted into the groove on the outer side wall of the lever-type variable iris; The first photoelectric switch blocking piece and the second photoelectric switch blocking piece are both machined with long slots. When the first photoelectric switch blocking piece and the second photoelectric switch blocking piece rotate counterclockwise with the driven gear, the first photoelectric switch blocking piece is inserted into the first photoelectric switch, and the extreme value of the change in the diameter of the lever-type variable aperture is adjusted by slightly adjusting the position of the first photoelectric switch blocking piece to block the first photoelectric switch. When the first photoelectric switch blocking piece blocks the first photoelectric switch, a signal is generated and fed back to the DC servo motor, causing the DC servo motor to stop working, thereby achieving electronic limit of the change in the diameter of the lever-type variable aperture to the extreme position. When the first photoelectric switch blocking piece and the second photoelectric switch blocking piece rotate clockwise with the driven gear, the second photoelectric switch blocking piece is inserted into the second photoelectric switch. When the second photoelectric switch blocking piece blocks the second photoelectric switch, a signal is generated and fed back to the DC servo motor, causing the DC servo motor to stop working, thereby achieving electronic limit of the change in the diameter of the lever-type variable aperture to the extreme position. When the first photoelectric switch is accidentally damaged and the electronic limit cannot be completed, causing the DC servo motor to be unable to stop working, the mechanical hard limit formed between the side surface of the iris gland and the left side surface of the upper end of the lever holder blocks the rotation of the driven gear, thereby protecting the lever-type variable aperture from damage. When the second photoelectric switch is accidentally damaged and the electronic limit cannot be completed, causing the DC servo motor to be unable to stop working, the mechanical hard limit formed between the side surface of the iris gland and the right side surface of the upper end of the lever holder blocks the rotation of the driven gear, thereby protecting the lever-type variable aperture from damage. The iris gland is an arc-shaped structure, and the opening at the lower end of the iris gland is aligned with the iris lever; It also includes a motor adapter mounted on the rear surface of the main support flange, and the DC servo motor is mounted on the motor adapter; A DC servo motor encoder is installed on the DC servo motor; The invention also includes a first baffle mounting seat and a second baffle mounting seat symmetrically mounted on the edge of the surface of the driven gear, the first baffle mounting seat and the second baffle mounting seat being symmetrically arranged on the left and right sides of the aperture gland; the first photoelectric switch baffle and the second photoelectric switch baffle are respectively mounted on the outer ends of the first baffle mounting seat and the second baffle mounting seat; The first photoelectric switch blocking piece and the second photoelectric switch blocking piece have the same structural dimensions.

Images