On The Technical Development Of Auto Repair Sheet Metal Workers


1、 Overview of body repair technology

In recent decades, the coordination and operation of automobile components have become more accurate and precise, and the mechanical failure rate of automobile engines and chassis has dropped significantly; a large number of advanced scientific and technological achievements have been adopted, the overall structure of automobiles has been constantly changing, and the entire automobile technology and automobile industry. rapid development. This makes modern automobiles a high-tech product integrating mechanics, electricity, hydraulics, and computers. Modern automobiles are developing in the direction of convenient driving, stable operation, comfortable riding, safety and reliability, energy saving and environmental protection.

In the process of automobile development, the change of the car body has become the most important assembly in the car. At present, most of the car body structures are used, and the connection method of the car body components has also changed, resulting in changes in the repair of the car body. The repair technology of the car body is mainly Focus on the separation, refurbishment, matching or replacement of new components of the car body. In the early days of automobile maintenance, damaged automobile components were directly removed and replaced with new ones, which was expensive and time consuming to wait for new components. With the professionalization of auto repair, the technology of body maintenance has also improved. Not only began to adopt the method of auto body correction and fixed body repair equipment, but also used lifting equipment to lift the car off the ground, so that the maintenance personnel can easily access the body parts, repairs are more efficient.

In addition, automotive body maintenance technicians should also formulate corresponding repair methods according to the structure, performance and component materials of the body. For example: various parts of the car’s monolithic body – control system, suspension system, cooling system, transmission equipment, electrical equipment, etc. are directly installed on the monolithic body, and repairs with very precise and reasonable positioning are required during maintenance. Methods, repair equipment should be simpler and can repair frameless body and frame body at the same time, and repair technology should be easy to popularize and adopt in the world, so that the body repair technology can be developed.

The type of car crash damage

The situation of automobile collision damage is very complex, which will be affected by various factors such as collision obstacles, environment, vehicle type, vehicle speed, collision position, driver’s adaptability, and automobile anti-collision performance. Automobile collisions are classified into two types: one is minor damage, which can be measured and inspected by visual inspection of the contact damage parts, important measurement points of body-related components, mechanics and electrical-related parts, and body system functions. The overall structure and parts of this kind of collision car are not affected, but the interior or reinforcement of the car body is damaged. When repairing, it is only necessary to replace the damaged f~9i% car external components or use a plastic repair machine and sheet metal tools to repair minor parts. The rubbing place can be rubbed, and finally the painting operation is completed after being inspected by the electromechanical engineer.

The other type is serious damage, not only the outer cover of the car body is damaged, but also; % The overall structure and components of the car are also affected, resulting in various forms of collision damage or deformation. This type of car collision damage repair requires not only the removal of the damaged coverings on the outside of the car body, but also the removal of the internal components, reinforcements and related parts of the car body, the correction and repair of the entire car body, and the replacement of damaged components. And it needs the cooperation of mechanical, electrical and sheet metal workers to be completely repaired. Nowadays, auto repair shops generally adopt the technology of mechanical and electrical integration, and use electronic control technology to diagnose mechanical faults. As long as the computer is connected, the fault code can be read out and the cause of the fault can be accurately determined, which is convenient and effective.

3. Technical requirements for automobile maintenance sheet metal workers

1.Master electronic technology and automation control technology

Automobile body manufacturing uses a lot of electronic technology and automatic control technology, such as: car parking assist system, door and window slope lift system, trunk lid lift system
And car folding roof system. These systems not only use automatic electronic control technology, but also hydraulic control technology, so the original sheet metal workers need to understand these technologies to repair successfully. Take a car parking assist system of a certain brand (Fig. 1) as an example. This system consists of circuits (Fig. 2), electronic components (Fig. 3), and electronic blocks (Fig. 4), etc. It involves many automatic technologies. This system also needs to be checked when inspecting the external repair of the car bumper, similar to the car door glass lift system (Figure 5).

2.Master the restoration of the folding hardtop body

Cars are not only a necessities of life, but also a consumer product, and many brand cars are also high-end consumer goods. Car manufacturers pursue a bright brand image of safety, comfort and luxury, and some cars also have high quality and safety requirements: the most ideal environmental protection, the most considerate of the interests of customers, the most reasonable structural design, etc. Take for example the BMW series convertibles produced in the spring of 2007 (Figure 6). The vehicle features a folding hardtop with a lightweight steel structure, with a fully automatic opening and closing mechanism that can open or close the roof within 25 seconds.

The rear view of the new BMW convertible is also very good. The rear side glass area is much larger than that of the previous generation model, so it is necessary to change lanes when changing lanes. It is more comfortable when driving maneuvers such as , cornering or parking.

A car with a foldable hard top has the advantages of high value retention, better anti-theft protection and less damage, all-weather adaptability, and sound insulation comparable to that of a hard-top sports car at high speeds (not exceeding 270 km/h). The folding height of the BMW foldable hardtop is also small (about 1.70cm), so it can be opened and closed even in the garage.

The three roof shells made of sheet steel have been optimised in terms of mass and rigidity. The luggage compartment lid is also constructed of sheet steel. The folding hardtop is driven by a central hydraulic unit that controls 8 hydraulic cylinders (movement process) and is supported by 6 inflatable struts during the movement process. The hydraulic assembly is controlled by the Convertible Roof Module (CTM) in a recess in the luggage compartment floor. The front roof is locked by a central motor in the housing and the folding roof system; the car frame is controlled by a linkage locking on the windshield panel and the central roof housing; The drive cable shaft (similar to the sliding sunroof drive mechanism) or the flexible thrust cable shaft are locked together; the luggage compartment lid is locked by the installed automatic soft closing function~(SCA1) In addition, the pound-type hardtop can be operated from the center console The central button on the top can also be opened directly with the remote control, and the folding hardtop can be stopped at any position during the moving process (opening/closing).

The body part of LL b}~ type is a combination of electronic technology, electronic control technology and hydraulic system. When repairing, it is necessary for automobile sheet metal workers to master many modern technologies such as body structure, folding principle and related electronic control technology. repair.

3.Master the repair of the electromechanical integrated structure of the stacked roof

Various installations and functions of automobiles, in order to achieve the ideal structure and pursuit of intelligence, often use a mechanical-electronic comprehensive structure.

(1) The structure of the luggage compartment lid and the “operation procedure”

When the trunk lid button is opened, a micro switch is activated and the junction box JB reads the status of the micro switch. JB sends a relevant message to CAS through K CAN. After successfully passing the inspection, CAS issues an authorization command, JBj ~ 2$ to unlock the luggage compartment lid and drive the device. The transmission operates the unlocking lever via a cable, and the right and left luggage compartment lid locks are unlocked. JB sends luggage compartment lid status (unlocked) via K-CAN.

The CTM receives the status signal, and then the CTM sends the SCA gear start command command, the transmission device reaches the ready position immediately, and can perform the shutdown process or auxiliary Complete the shutdown process.When the luggage compartment lid is closed, the SCA transmission is in the ready position .When the left and right luggage compartment lid locks reach the lever position, two microswitches actuate.Controlled, the switch status information is read by the CTM.The CTM then controls the two SCA drives device (one microswitch on each SCA’~!F actuator) until the other two microswitchesThe type switch sends a “Luggage compartment lid locked” status signal to the CTM.

The automatic soft-close function transmission is not required for manual closing of the luggage compartment lid operate.However, in order to ensure safety and the luggage compartment lid is actually closed, the automaticSoft close function transmission. When the limit position of the SCA actuator is in the “unlocked” state, the relevant signals are sent to the CTM through the other two microswitches.

(2) Double locking device

In order to ensure the stable and reliable operation of the car roof, each automatic soft closing function transmissionThe units have a double locking mechanism to prevent overheating of the automatic soft-close function transmission.The device allows the operation of the automatic soft-off function transmission20times (counter increments up to20times), then electrically deactivate the automatic soft-off function of the drive for approximately2minthe device is a foldable canopy structure (Fig.7).

The rear module (Fig. 8) is the rear module of the roof, the rear module is The support rod structure of the support is fixed on the body, the mass of the rear module is about 40Kq, and the luggageThe compartment cover has an automatic soft closing function.

( 3) Electromechanical and control sensor device

In order to ensure the stable and reliable operation of the roof, electromechanical and control sensing devices will be used.That is, the “roof shell part open/close” Hall sensor device.on the right side of the roof shell fluidTwo Hall sensors are mounted on the pressure cylinder to detect the piston in the hydraulic cylinder of the roof shell mobile situation.When the piston is removed, the “roof shell partially open” Hall sensor willCTM sends a signal.In this position, the roof shells It can be stored in the luggage at this time.The piston in the hydraulic cylinder of the roof shell is almost completelyWhen moved in, the “Roof Shell Partially Closed” Hall sensor sends a Signal.From this position, the hard J page slows the closing speed until it reaches the sash panel(Indirect anti-pinch protection function)

The right side of the bulkhead formwork is fitted with the Hall sensor of the roof unit, and the rear formwork has A bow, when the limit position is reached, the Hall sensor will send aA signal, the bow will change the voltage inside the Hall sensor.

Hall sensors for the “Roof kit retract” process are installed in the luggage compartment on the right bottom plate.When the guide pins of the front roof shell reach the guide rails in the floor The Hall sensor sends a signal to the CTM.From this position, the hard The transmission of the top locking device and the rear module can be closed again (Fig. 9).

The repair of these automobile structures and components is very complicated. Car sheet metal work can not be completed at all, so improving the technical skills of car sheet metal work is a musturgent.At present, many cities have not arranged for car sheet metal technicians to train. training, even many on-the-job car sheet metal workers have never been trained, such a feeling; brotherMust attract the attention of technical management at all levels ~ l S f 3, only to strengthen the training of automotive sheet metal workers,To promote the development of the auto repair industry

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