Back focus adjusting module
By using oblique gear rack transmission mechanisms in the ABF focus module, the rotation movement is converted into a straight line motion, which solves the problem of large noise and low loading capacity of traditional focus modules, and improves the transmission accuracy and imaging quality.
Patent Information
- Application Number
- CN202420653454.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-01
- Publication Date
- 2025-01-24
- Estimated Expiration
- 2034-04-01
AI Technical Summary
The driving components of traditional ABF focus modules have problems such as high noise and low load-bearing capacity, which leads to large mechanical vibrations throughout the module during the adjustment process, affecting the imaging quality.
The oblique gear rack transmission mechanism is used to convert the rotation movement output of the gear reducer into a linear motion, which accurately drives the activity bracket for post -focus adjustment, which improves the transmission accuracy and service life of the regulating module.
Through the helical rack and pinion transmission mechanism, the transmission accuracy and service life of the adjustment module are improved, the imaging quality is enhanced, and the generation of loud noise is avoided.
Smart Images
Figure CN222394207U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of focusing module structures, in particular to a back focus adjustment module. Background Art
[0002] ABF (Auto Back Focus) focusing module, that is, automatic back focus adjustment module, is used to automatically adjust the back focus of the lens to ensure that the image remains clear at all times. Its working principle is to change the back focus of the optical system by driving the lens or image sensor forward and backward through the driving component.
[0003] The driving components of the traditional ABF focusing module have problems with high noise and low load-bearing capacity, which causes the entire module to generate large mechanical vibrations during the adjustment process. In addition, the lens bracket is prone to shaking and has poor stability, which has a significant impact on image quality. Utility Model Content
[0004] The purpose of the utility model is to provide a back focus adjustment module to solve one or more technical problems existing in the above-mentioned background technology.
[0005] To achieve this purpose, the utility model adopts the following technical solutions:
[0006] A back focus adjustment module comprises a fixed base, a movable bracket and a driving assembly, wherein the movable bracket is provided with a mounting bracket for mounting a lens or an image sensor, the movable bracket is slidably connected to the fixed base, the driving assembly is arranged on the fixed base, and the movable bracket is connected to the movable end of the driving assembly; the driving assembly comprises a driving motor, a gear reduction box, and a helical rack and pinion transmission mechanism, the rotating shaft end of the driving motor is connected to the input end of the gear reduction box, the output end of the gear reduction box is connected to the input end of the helical rack and pinion transmission mechanism, and the output end of the helical rack and pinion transmission mechanism is connected to the movable bracket.
[0007] Preferably, the helical gear rack transmission mechanism includes a transmission shaft, a helical gear and a helical rack, one end of the transmission shaft is connected to the output end of the gear reduction box, the helical gear is sleeved on the outside of the transmission shaft, the helical rack is arranged on one side of the movable bracket, and the helical gear is meshed with the helical rack.
[0008] Preferably, the tooth width of the helical gear is greater than the tooth width of the helical rack.
[0009] Preferably, the helical gear rack transmission mechanism further includes a clamping ring, a limiting groove is provided at the other end of the transmission shaft, the clamping ring is arranged in the limiting groove, and the clamping ring is fitted with the end of the helical gear.
[0010] Preferably, the fixed base is provided with a motor mounting plate parallel to the movable direction of the movable bracket, the gear reducer is fixed on one side of the motor mounting plate, the transmission shaft extends to the other side of the motor mounting plate, and the drive motor is fixed on one side of the gear reducer.
[0011] Preferably, the drive assembly also includes a front limit sensor and a rear limit sensor, and the front limit sensor and the rear limit sensor are arranged front and back on the fixed base, and a sensor plate is provided on one side of the movable bracket, and the sensor plate corresponds front and back to the sensing ends of the front limit sensor and the rear limit sensor.
[0012] Preferably, it also includes a guide column and a linear bearing, the bottom of the movable bracket is provided with a mounting seat, the linear bearing is embedded in the mounting seat, the guide column is arranged in the fixed base, the guide column is located on both sides of the helical gear rack transmission mechanism, and the inner side of the linear bearing is slidably matched with the guide column.
[0013] Preferably, it further comprises a compression spring, wherein the compression spring is sleeved on the outer side of the guide column, and the two ends of the compression spring are respectively against the top of the fixed base and the end surface of the linear bearing.
[0014] Compared with the prior art, the beneficial effects of the utility model are as follows: the utility model adopts a helical gear rack transmission mechanism, which converts the rotational motion output by the gear reducer into linear motion through the helical gear rack transmission mechanism, thereby accurately driving the movable bracket to adjust the back focus, improving the transmission accuracy and service life of the adjustment module, helping to improve the imaging quality, and avoiding the generation of loud noise. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings further illustrate the present invention, but the contents in the accompanying drawings do not constitute any limitation to the present invention.
[0016] Figure 1 It is a schematic diagram of the overall structure of one embodiment of the utility model;
[0017] Figure 2 This is a schematic structural diagram of a helical gear rack transmission mechanism of one embodiment of the utility model;
[0018] Figure 3 yes Figure 2 A partial enlarged schematic diagram of
[0019] Figure 4 It is a schematic diagram of the internal structure of one embodiment of the utility model.
[0020] Among them: fixed base 1, movable bracket 2, mounting bracket 21, driving motor 3, gear reduction box 4, helical gear rack transmission mechanism 5, transmission shaft 51, helical gear 52, helical rack 53, clamping ring 54, limit groove 511, motor mounting plate 11, front limit sensor 55, rear limit sensor 56, sensor sheet 57, mounting seat 22, guide column 61, linear bearing 62, and compression spring 63. DETAILED DESCRIPTION
[0021] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.
[0022] A back focus adjustment module of this embodiment is shown in the attached Figure 1 and 2 , including a fixed base 1, a movable bracket 2 and a driving assembly, the movable bracket 2 is provided with a mounting bracket 21 for mounting a lens or an image sensor, the movable bracket 2 is slidably connected to the fixed base, the driving assembly is arranged on the fixed base 1, and the movable bracket 2 is connected to the movable end of the driving assembly; the driving assembly includes a driving motor 3, a gear reduction box 4, and a helical gear rack transmission mechanism 5, the rotating shaft end of the driving motor 3 is connected to the input end of the gear reduction box 4, the output end of the gear reduction box 4 is connected to the input end of the helical gear rack transmission mechanism 5, and the output end of the helical gear rack transmission mechanism 5 is connected to the movable bracket 2.
[0023] This embodiment adopts a helical gear rack transmission mechanism 5, which converts the rotational motion output by the gear reduction box 4 into a linear motion, thereby accurately driving the movable bracket 2 to adjust the back focus, improving the transmission accuracy and service life of the adjustment module, helping to improve the imaging quality, and avoiding the generation of large noise. The setting of the gear reduction box 4 also plays a role in increasing the torque, further improving the stability of the driving of the movable bracket 2.
[0024] Preferably, the helical gear rack transmission mechanism 5 includes a transmission shaft 5, a helical gear 52 and a helical rack 53. One end of the transmission shaft 5 is connected to the output end of the gear reduction box 4. The helical gear 52 is sleeved on the outer side of the transmission shaft 5. The helical rack 53 is arranged on one side of the movable bracket 2. The helical gear 52 is meshed with the helical rack 53. The helical gear 52 with a diagonal tooth surface is meshed with the helical rack 53, so that the transmission is more stable, the impact and vibration are smaller, and compared with other focusing mechanisms, the helical gear 52 is more closely meshed, the backlash (i.e., the gap during forward and reverse rotation) is reduced, and the accuracy and consistency of the focusing process of the focusing module are ensured, and the structure is simple. In addition, the tooth surface contact line of the helical gear 52 and the helical rack 53 is long, the contact area is large, and the load-bearing capacity is high, which further improves the stability of the driving of the movable bracket 2.
[0025] Furthermore, the tooth width of the helical gear 52 is greater than the tooth width of the helical rack 53. By setting the helical rack 53 with a larger tooth width than the helical rack 53, the contact area between the tooth surface of the helical gear 52 and the tooth surface of the helical rack 53 is increased, the stability of the transmission is improved, and the transmission error or vibration caused by poor contact of the tooth surface is avoided. The helical gear 52 with a larger tooth width can also better disperse the load during the transmission process, reduce the pressure per unit area, thereby reducing the risk of wear and fatigue damage on the tooth surface, and improve the service life of the helical gear 52 and the helical rack 53.
[0026] Preferably, refer to the attached Figure 3 The helical gear rack transmission mechanism 5 further includes a clamping ring 54. A limiting groove 511 is provided at the other end of the transmission shaft 5. The clamping ring 54 is arranged in the limiting groove 511. The clamping ring 54 fits with the end of the helical gear 52. By providing the limiting groove 511 at the other end of the transmission shaft 5 and fixing the clamping ring 54 in the limiting groove 511, the clamping ring 54 fits with the end of the helical gear 52, thereby effectively preventing the helical gear 52 from axially moving during the transmission process, ensuring that the helical gear 52 and the helical rack 53 are properly meshed, and avoiding the transmission failure caused by the displacement of the helical gear 52.
[0027] Preferably, a motor mounting plate 11 parallel to the movable direction of the movable bracket 2 is provided on the fixed base, the gear reducer 4 is fixed on one side of the motor mounting plate 11, the transmission shaft 5 extends to the other side of the motor mounting plate 11, and the drive motor 3 is fixed on one side of the gear reducer 4.
[0028] By arranging the motor mounting plate 11 on the fixed base and fixing the gear reduction box 4 on one side of the motor mounting plate 11, the layout of the drive assembly is made more compact and reasonable, the space is effectively utilized, and the overall volume of the module is reduced. By arranging the motor mounting plate 11 parallel to the movable direction of the movable bracket 2, the transmission shaft 5 can be directly extended to the other side of the motor mounting plate 11 and connected to the bevel gear 52, ensuring that the bevel gear 52 and the bevel rack 53 are effectively meshed.
[0029] Preferably, refer to the attached Figure 4 The driving assembly further includes a front limit sensor 55 and a rear limit sensor 56, which are arranged front and rear on the fixed base 1, and a sensing sheet 57 is arranged on one side of the movable bracket 2, which corresponds to the sensing ends of the front limit sensor and the rear limit sensor. The front limit sensor 55 and the rear limit sensor 56, which are arranged front and rear, are used to control the travel range of the movable bracket 2. When the movable bracket 2 moves to the preset front limit or rear limit position, the corresponding sensor is triggered to stop the movable bracket 2 from moving in the direction, thereby avoiding direct collision between the movable bracket 2 and the fixed base 1 and prolonging the service life of the adjustment module.
[0030] Preferably, it further comprises a guide column 61 and a linear bearing 62, a mounting seat 22 is provided at the bottom of the movable bracket 2, the linear bearing 62 is embedded in the mounting seat 22, the guide column 61 is provided in the fixed base 1, the guide column 61 is located on both sides of the helical gear rack transmission mechanism 5, and the inner side of the linear bearing 62 is slidably matched with the guide column 61. Thus, by providing the guide column 61 and the linear bearing 62, the sliding match between the movable bracket 2 and the fixed base 1 is achieved.
[0031] Furthermore, a compression spring 63 is included, which is sleeved on the outside of the guide column 61, and the two ends of the compression spring 63 are respectively against the top of the fixed base 1 and the end surface of the linear bearing 62. By arranging the compression spring 63 between the top of the fixed base 1 and the linear bearing 62, the pressure provided by the compression state of the compression spring 63 is used to act on the end surface of the linear bearing 62, thereby further reducing the meshing clearance between the helical gear 52 and the helical rack 53, thereby improving the transmission accuracy.
[0032] The technical principle of the present invention is described above in combination with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the protection scope of the present invention in any way. Based on the explanations here, technicians in this field can think of other specific implementation methods of the present invention without creative work, and these methods will fall within the protection scope of the present invention.
Claims
1. A back focus adjustment module, characterized in that: It includes a fixed base, a movable bracket and a driving assembly, the movable bracket is provided with a mounting bracket for mounting a lens or an image sensor, the movable bracket is slidably connected to the fixed base, the driving assembly is arranged on the fixed base, and the movable bracket is connected to the movable end of the driving assembly; the driving assembly includes a driving motor, a gear reduction box, and a helical gear rack transmission mechanism, the rotating shaft end of the driving motor is connected to the input end of the gear reduction box, the output end of the gear reduction box is connected to the input end of the helical gear rack transmission mechanism, and the output end of the helical gear rack transmission mechanism is connected to the movable bracket.
2. A back focus adjustment module according to claim 1, characterized in that: The helical gear rack transmission mechanism includes a transmission shaft, a helical gear and a helical rack. One end of the transmission shaft is connected to the output end of the gear reduction box. The helical gear is sleeved on the outside of the transmission shaft. The helical rack is arranged on one side of the movable bracket. The helical gear is meshed with the helical rack.
3. A back focus adjustment module according to claim 2, characterized in that: The tooth width of the helical gear is greater than the tooth width of the helical rack.
4. The back focus adjustment module according to claim 2, characterized in that: The helical gear rack transmission mechanism also includes a clamping ring. A limiting groove is provided at the other end of the transmission shaft. The clamping ring is arranged in the limiting groove. The clamping ring is fitted with the end of the helical gear.
5. The back focus adjustment module according to claim 2, characterized in that: The fixed base is provided with a motor mounting plate parallel to the movable direction of the movable bracket, the gear reduction box is fixed on one side of the motor mounting plate, the transmission shaft extends to the other side of the motor mounting plate, and the drive motor is fixed on one side of the gear reduction box.
6. The back focus adjustment module according to claim 1, characterized in that: The driving component also includes a front limit sensor and a rear limit sensor, which are arranged front and back on the fixed base, and a sensing sheet is provided on one side of the movable bracket, and the sensing sheet corresponds front and back to the sensing ends of the front limit sensor and the rear limit sensor.
7. The back focus adjustment module according to claim 1, characterized in that: It also includes a guide column and a linear bearing. A mounting seat is provided at the bottom of the movable bracket, the linear bearing is embedded in the mounting seat, the guide column is arranged in the fixed base, the guide column is located on both sides of the helical gear rack transmission mechanism, and the inner side of the linear bearing is slidably matched with the guide column.
8. The back focus adjustment module according to claim 7, characterized in that: It also includes a compression spring, which is sleeved on the outside of the guide column, and the two ends of the compression spring are respectively against the top of the fixed base and the end surface of the linear bearing.