Application of the hottest motor in the field of i

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Applications of motors in the field of information technology (3)

3.3 laser video disc

the optical drives that play video and audio signals include laser video disc (LD), video compression disc (VCD) and digital video disc (DVD)

The typical working principle block diagram of the laser video disc is shown in Figure 19

take the VCD applied to the laser disc as an example, generally three motors are required as the power source of the mechanism system:

(1) the permanent magnet constant speed DC motor

is used to drive the VCD tray and pressure mechanism, as shown in Item 1 of figure 19 (tray motor)

(2) use the sheet brushless DC motor

to drive item 2 (disc) to rotate, as shown in Item 3 (spindle motor) in Figure 19. This is a new type of motor with axial magnetic circuit, permanent magnet excitation and thin sheet. Its basic principle has no essential difference from the traditional permanent magnet DC motor, and it mainly pursues miniaturization and thinning. The structural diagram can be seen from Figure 20

the structure of the film material cross-border grafting brushless DC motor used in audio-visual equipment strives to be miniaturized and thin. The precise lithography process can be used to etch item 4 (armature coil) on the copper foil plate. In order to ensure that the small and thin motor can produce sufficient torque, item 3 (permanent magnet) now adopts Nd-Fe-B permanent magnet. Since there is no core, the torque fluctuation, vibration and noise caused by cogging effect will be minimized. Item 6 (printed board) can generally be composed of a distributor (CH250), an external synchronous circuit (CP pulse generator), a back EMF detection circuit (LM324) and a power drive to directly drive the brushless DC motor to rotate. The main performance indexes of sheet brushless DC motor are: rated voltage 1.5 ~ 12V, rated torque 0.294 ~ 4.9mnm, rated speed 2200 ~ 7000 R/min, rated current 0.105 ~ 0.39a, and the overall dimensions are Φ 25mm × 4.1mm, Φ 30mm × 4.1mm, Φ 62.7mm × 10mm,40mm × 40mm × 5.8mm。 Weight: 15 ~ 300g. Due to its many advantages, such as long-lasting sheet, it has been widely used in the field of information electronics, such as laser video discs, headphone stereo recorders, video recorders, and so on. It can also be widely used in household air conditioners as the drive of air purification fans. Considering the manufacturing cost, at present, common permanent magnet constant speed DC motors are widely used in the spindle motors of VCD and DVD players

3.4 image input machine

3.4.1 classification

the classification of image input machine includes camera, scanning drum, laser scanner, infrared imager, etc. These devices are mainly used in industry (such as robots, material inspection), medicine (such as X-ray, ultrasound, CT image diagnosis) and remote sensing. The following classification introduces the main selection of motors

3.4.2 camera

the function of the camera is to turn images into video signals. Its basic principle is shown in Figure 21

take the integrated video recorder as an example, there are 6 motors in the camera, which are: ① spindle motor. ② Drum motor. ③ Loading motor (see "classification table of motor for video recorder" for the types, functions, characteristics and indicators of the above motors). ④ Focusing motor. ⑤ Zoom motor. ⑥ Aperture motor. The drive motor in ④ - ⑥ adopts permanent magnet DC steady speed motor. The basic requirement is to ensure that the speed and shaking error are small under the adverse conditions of load change or power supply voltage change. According to the principle of speed stabilization, there are three kinds: centrifugal speed stabilization, electronic speed stabilization and servo control system. The first two kinds are used for medium and low-grade machines, and the latter is mainly used for high-grade machines

3.4.3 schematic structure of scanning drum

is shown in Figure 22

wrap the paper with image around item 13 (reading drum), and item 10 (drive circuit) controls item 11 (drum motor) to drive item 13 (reading drum) to rotate, so as to implement line scanning. On the other way, item 15 (stepping motor) drives item 14 (reading head) to translate by item 16 (driver), so as to complete the scanning of the whole image

the signal from item 6 (CPU) is sent through item 7 (Interface) and D/a converter to item 5 (inverse logarithm circuit) and item 2 (optical modulation amplifier) and item 3 (reflector), and then the image is input to item 12 (write drum)

item 11 (drum motor) adopts permanent magnet DC servo motor with stable speed requirements. Item 15 (stepping motor) adopts permanent magnet stepping motor structure, which has the advantages of simple structure, convenient control, positioning torque after power failure, etc. the main performance indicators are: Voltage 5V, 12V, 24V, 30V; The maximum static torque is 4.9 ~ 140mnm, the positioning torque is 0.49 ~ 22mnm, the no-load starting frequency is 240 ~ 950 pulses/s, and the overall dimensions Φ 20mm,25mm,42mm,55mm。

3.4.4 see Figure 23 for the working principle diagram of the laser scanner

put the image text to be input on the working surface of item 1 (flat plate), and item 2 (DC motor 1) drives item 1 to move forward at a constant speed in a straight line. The laser beam is emitted from item 6 (laser), passes through item 5 (dichroic mirror) → item 4 (correction scanning mirror) → item 7 (focusing lens) → item 8 (scanning mirror), and then reaches the image along the direction of the light arrow to form a scanning line. And item 3 (DC motor 2) completes the reverse operation. DC motors in Items 2 and 3 are required to have speed stabilization function

3.4.5 infrared imager

this is a high-tech information transmission product before starting the bellows ring stiffness testing machine. According to the energy emitted by the tested object, it can be converted into clear images through the low-speed DC torque motor with incremental code disk lock-in and photoelectric control system. It has been applied in aviation, navigation, medical diagnosis and other fields. Main indicators of low-speed DC torque motor: blocking speed 60R/min, torque fluctuation ≤± 5%, overall dimension Φ 40mm × 20mm。

4 office equipment

4.1 printer

printer is a very important and commonly used tool in computer system output equipment

4.1.1 classification of printers and motors

according to printers, there are percussive (needle lattice) and non percussive. The former has 24 Chinese characters, 9 characters and miniature; The latter includes laser, inkjet and heat transfer. Drive motors: by stepping motors are widely used in 9-pin character and micro printers, and their outer diameters are Φ 20mm, 25mm, 35mm, 42mm, four phase drive, its step torque angle is 7.5 °/15 °, the voltage is 5 ~ 28V, and the maximum static torque is 7.35-78.4mnm. BH stepping motor is widely used in 24 pin printers, with an overall dimension of 40mm × 36mm,42mm × 36.5mm,57mm × 52mm, step torque angle 1.8 °, excitation voltage 12V, maximum static torque 70 ~ 280mnm

4.1.2 serial dot matrix printer

taking the serial dot matrix printer as an example, this paper introduces the specific application of stepping motor, as shown in Figure 24

driven by item 3 (zigzag stepping motor) through item 6 (synchronous belt), item 8 (zigzag car) makes reciprocating linear motion along item 7 (guide rail); Item 5 (paper feeding stepper motor) drives item 1 (printing paper) to move vertically through item 2 (paper feeding roller); Item 6 (synchronous belt) drives the gear and reversing mechanism to drive Item 9 (color belt drive shaft). Item 4 (light shed) detects each optical signal to determine the position of item 8 (word car). Items 3 and 5 all use four phase stepping motors

in the color laser printer, the paper feed and output drive adopts brushless DC motor, and its indicators are: rated voltage 25.5v, rated speed 2100r/min, rated torque 88.2mnm, outer diameter size Φ 60mm, the control board is assembled with the outer rotor motor

4.2 laser printer

in the laser printer with the highest printing speed and resolution, the steady speed drive adopts brushless DC motor. See Figure 25 for the working principle

the light source modulated by the binary information character lattice output by the computer sends out the laser beam through item 2 (semiconductor laser), and is shaped into a collimated beam through item 3 (collimating lens). After entering item 5 (polyhedral rotating mirror), item 6 (brushless DC constant speed motor) drives item 5 to rotate together, so as to form the scanning of the laser beam, which is projected onto item 1 (photoconductive drum) through Item 9 (focusing lens), forming a row of lattice. After the above pre scanning is completed, the controller generates a page synchronization signal and the control board of the page memory sends a video signal to scan and expose the text or image of item 1 to form an electrostatic latent image of the text or image. After the development of item 8 (developer) and the transfer, separation and fixing of items 10-14, the printing of words or images can be completed. Therefore, the speed stability of item 6 is highly required. The rated voltage of brushless motor is 12 and 24V, the output power is 0.2 ~ 18W, the speed is 400 ~ 4000R/min, the current is 0.15 ~ 2a, and the starting time is 0.1 ~ 3S

4.3 fax machine

4.3.1 main functions

fax machine is a high-tech information transmission equipment, which can quickly transfer text and image information in paper. Take the inkjet desktop-84-fax receiving transmitter as an example, it has the following main functions:

(1) inkjet printing on plain paper. (2) 14.4kb/s high-speed fax. (3) It can store 80 pages of manuscripts. (4) Display and report functions in 7 languages (English, German, French, Italian, Spanish, Portuguese and Netherlands). (5) With, copy, fax, automatic response function

4.3.2 apply

to the sending and receiving motor for optical scanning in the fax machine. AC synchronous motor is used, and the transmission recording paper adopts the method of nylon gear driven by stepper motor. The voltage of stepper motor is 12V, 24V; Step torque angle 3.75 °, 7.5 °; Driving mode: 1-2, 2-2 phases; The overall dimension is generally Φ 35mm × 15mm, higher power Φ 42mm × 22mm。 At present, the types of motors used in fax machines are stepping motors, which can also complete functions such as paper cutting

4.4 copier

4.4.1 working principle

copier is a product of optical, electromechanical and chemical integration, which is widely used in the field of paper-based information office. The copier made by using the principle of static electricity is a kind of office appliance with universal use. At present, it is developing in the direction of color electrostatic copying

the basic principles of all kinds of electrostatic copiers are the same, but their working process is relatively complex. Domestic copiers use selenium as the conductive layer, and the maximum copy format is 2797mm × 420mm, copying speed 10 ~ 16 sheets per minute. Several micro motors are required to complete different functions, and their structures are shown in Figure 26

4.4.2 application

in Figure 26, item 4 (selenium drum assembly) is driven by a 4-pole single-phase asynchronous motor, with a power of 120W, a working current of 2a, a starting current of 12.5A, and a starting torque/rated torque multiple of 1.7; The brushing part of item 5 (brush assembly) is in contact with Item 4. The 4-pole single-phase capacitive asynchronous motor for powder brushing has a working current of 0.4A and a starting torque/rated torque multiple of 0.5; The air pump of item 6 (dust collection room) is driven by a 2-pole single-phase capacitive asynchronous motor, with a power of 60W and a starting torque/rated torque multiple of 0.35; Item 8 (wire feeding wheel) consists of a toothed belt wheel and a one-way wheel. In order to keep the paper feeding speed synchronized with the operation of item 4, a single-phase reactive synchronous motor is used, with a voltage of 127V, an input power of 10W, a working current of 0.1A and a working speed of 1500 R/min; The ventilation and cooling of item 3 (optical system) adopts single-phase axial flow fan, with fan blade diameter of 125mm, rotating speed of 3000r/min and air volume of 2.5m3/min; The ventilation and cooling of item 7 (infrared developer) also adopts single-phase axial flow fan, with fan blade diameter of 100mm, rotating speed of 3000 R/min and air volume of 1.4m3/min

4.4.3 motor type

due to the improved structure and increased functions, the new generation of copiers mainly adopt the following five types of motors:

(1) spindle

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