At present, the four-wheel locators on the market are mainly conventional and advanced. There are conventional 2D four-wheel positioning and advanced 3D four-wheel positioning. Four wheel alignment types The four-wheel locator has a front beam ruler, an optical level locator, a pull locator, a CCD locator, a laser locator, and a 3D image locator. Among them, 3D, CCD and laser products are currently the three mainstream products on the market. 3D products are the most advanced four-wheel positioning on the market. The measurement methods are advanced, and the measurement time is only one-fifth that of conventional locators. It has gradually matured. . In the Beijing exhibition, all major four-wheel-position manufacturers showed V3D four-wheel positioning products, and V3D became the biggest highlight of the show. The major four-wheel alignment manufacturers have launched their own V3D products, and the V3D market battle will surely begin immediately. The V3D measurement capability surpasses the optical sensor. In addition to the ability to calculate the four-wheel alignment angle, it can also calculate the wheelbase, wheel alignment, wheelbase, axle difference, friction radius, steering trajectory and other functions. Moreover, optical sensors are many after sales, and the operation is cumbersome. The emergence of V3D is very likely to replace the market segment of medium and high-end optical machines. The four-wheel alignment is based on the four-wheel parameters of the vehicle, and is adjusted to ensure good driving performance and certain reliability. The installation of the car between the steering wheel, the knuckle and the front axle has a certain relative position. This kind of installation with a certain relative position is called the steering wheel positioning, also called the front wheel positioning. The front wheel positioning includes four contents of kingpin reclining (angle), kingpin inclination (corner), front wheel camber (corner) and front wheel toe. This is for the two steering front wheels. For the two rear wheels, there is also a relative position between the rear axle and the rear axle. Rear wheel alignment includes wheel camber (angle) and front-to-back rear wheel. In this way, the front wheel positioning and the rear wheel positioning are collectively referred to as four-wheel positioning. The installation between the steering wheel, the steering knuckle and the front axle of the automobile has a certain relative position. This kind of installation with a certain relative position is called the steering wheel positioning, also called the front wheel positioning. The front wheel positioning includes four contents of kingpin reclining (angle), kingpin inclination (corner), front wheel camber (corner) and front wheel toe. The role of cars in four-wheel alignment 1. Increase driving safety; 2. Reduce tire wear; 3. Maintain the straightness of the steering wheel while keeping straight, and maintain straight-line driving; 4. Steering after the steering wheel is automatically converted; l increase the sense of driving control; 5. Reduce the consumption of combustion; 6. Reduce the wear of suspension components. When the vehicle is used for a long time, the user finds that the direction is heavy, trembling, misaligning, unjust, non-homogeneous, or tire wear, wave wear, block wear, eccentric wear and other abnormal wear, and the user when driving, the car When a floating, bumpy, swaying, etc. phenomenon occurs, you should consider checking the wheel alignment value to see if there is too much deviation and repair it in time. The front wheel positioning includes the four contents of the kingpin caster, the kingpin caster, the front camber, and the front wheel toe. The rear wheel alignment includes wheel camber and front-to-back rear wheels. In this way, the front wheel alignment and rear wheel alignment are collectively called wheel alignment, which is often referred to as four-wheel alignment. The role of wheel alignment is to make the car maintain a stable straight line and turn the light, and reduce the wear and tear on the tires and steering parts in the car. Master pin caster From the side view of the wheel, the steering kingpin (the center of rotation when the wheel is turning) is tipped backwards, called the kingpin caster. After setting the caster angle, the distance between the ground point of the centerline of the kingpin and the ground projection point of the center of the wheel (referred to as the kingpin pitch, which is the same as the principle that the front fork of the bicycle tilts backward), The grounding point of the wheel is located at the rear end of the extension line of the steering kingpin, and the wheel is pulled back by the rolling resistance during running, so that the direction of the wheel is naturally oriented toward the running direction. Setting a large kingpin caster improves the straight line. Kingpin inclination When looking at the tire in the front-rear direction of the vehicle, the main pin is inclined inwardly of the body, and this angle is called the kingpin inclination. When the wheel is turning with the kingpin as the center, the lowest point of the wheel will fall below the road surface, but in fact the lower edge of the wheel is unlikely to fall below the road surface, but the steering wheel together with the entire front of the car is lifted up by a corresponding height. The gravity of the car itself has the effect of returning the steering wheel to its original neutral position, and the steering wheel is easily reset. In addition, the kingpin inclination also reduces the distance between the kingpin axis and the intersection of the road surface to the centerline of the wheel and the intersection of the ground, thereby reducing the driver's force on the steering wheel during steering, making steering easier and at the same time reducing Impact force from the steering wheel to the steering wheel. However, the kingpin inclination should not be too large, otherwise it will accelerate the wear of the tire. Front wheel camber When looking at the wheel in the fore-and-aft direction, the tire is not mounted vertically. Instead, it is slightly tilted to show an “eight†shape that is called a negative camber, and when it is opened in the opposite direction, it is called a positive camber. During the heyday of using slash tires, the camber angle is set to be relatively large because the tilting of the tire to the ground facilitates the operation of the steering wheel. The car generally sets the camber angle to be very small and close to vertical. The flat radial tires for automobile installations continue to gain popularity. Due to the characteristics of radial tires (large tread pattern rigidity and wide tread width), setting a large camber angle will cause tires to wear out and reduce tire friction. Thanks to the constant use of steering aids, the camber angle has also been continuously reduced. However, setting a slight camber can apply proper lateral thrust to the wheel bearings on the axle. Front toe Toe inwards, the so-called "inside-foot" means that the left and right front wheels are inward respectively. The purpose of this structure is to correct the outward rotation of the wheel caused by the camber of the front wheel. As described above, the steering wheel becomes easy to handle because of the camber. On the other hand, because the wheels are inclined, the left and right front wheels turn outward respectively. To correct this problem, if the right and left wheels have an inward angle, the positive and negative sides are zero, and the left and right wheels can maintain a straight line to reduce tire wear. The above four kinds of positioning values ​​are indicators of front wheel positioning. The rear-wheel positioning value is similar to the front-wheel positioning value, but most car rear-wheel positioning is not adjustable. What circumstances need to do four wheel alignment If the data in your vehicle specification is the same as the data in the four wheel alignment computer, it is universal. In general, four-wheel positioning is required in the following situations. 1ã€After replacing a new tire or after a collision accident has been repaired; 2ã€The front and rear tires are unilaterally worn; 3ã€The steering wheel is too heavy or flutters when driving; 4. The car goes left or right when going straight; 5ã€Although no more Condition, but for maintenance purposes, it is recommended that the new car be driven 3 months later, half a year or 10,000 kilometers. Four wheel alignment benefits Four-wheel alignment is one of the essential tasks for vehicle maintenance. Unless there are obvious problems associated with it before doing four-wheel alignment, such as poor straight-line stability, you can feel it immediately after four-wheel alignment. Otherwise, it is difficult to judge whether you are doing well or not. Since the quality of auto repair industry is uneven, and the quality of maintenance varies greatly, it is recommended that you try to maintain the quality of the four-wheel alignment to ensure better traffic safety. Its benefits are: 1. To enhance driving comfort; 2. To reduce gas consumption; 3. To increase the service life of the tire 4. To ensure the stability of the vehicle's straight line; 5. To reduce the wear of the chassis suspension accessories; 6. To enhance driving safety Misunderstanding Misunderstanding 1: Think that doing four-wheel alignment is to adjust the front wheel toe "four-wheel alignment" As the name implies, it is necessary to consider the positioning of the four wheels of a car. The toe is an angle concept, technically known as toe angle. In the past, when Master was not equipped with technical data and wheel alignment equipment in the maintenance workshop, he could only rely on experience to measure the difference between the front and rear of the two front wheel diameters by using a metric meter. Many people used to seeing the front-end beam. For the length concept. In fact, the front wheel has not only the toe angle, but also the camber angle, kingpin caster angle and kingpin inclination angle; the rear wheel also has toe angle, as well as the main camber angle and camber angle. When doing four-wheel alignment, the rear-wheel positioning angle is more important, and the kind of thinking that “doing four-wheel alignment is to adjust the front wheel toe†is one-sided and even wrong. 123 Show on this page Myth #2: Where is the charge? Since the beginning of the new century, with the rapid increase in the number of domestic car ownership, many domestic and foreign manufacturers of four-wheel aligners have competed to occupy the market. Various types of locators with different quality and quality have mushroomed into the market. The market competition has greatly reduced the profit margins of manufacturers and distributors. There is no intellectual property and no technical content Locator manufacturers compete to lower prices. The relative popularity of locators has exacerbated the competition among maintenance companies, and many maintenance companies are targeting customers at lower prices. The reason for the low fees is not because the productivity of the maintenance companies has increased, but more because the technical content and measurement accuracy of the equipment are not high. In order to survive, some maintenance companies can only be short of two short positions when positioning. Naturally there is no fundamental solution. Myth 3: Practitioners lack necessary knowledge The employees of the majority of four-wheel alignment maintenance companies seldom accept the training of professional knowledge and skills. Most of them stay in the state of self-study while doing their homework. Misunderstanding 4: Maintenance personnel skip key operations Defrauding users Most users know little about the four-wheel positioning knowledge. It is very difficult for car owners to do wheel alignment, and it is even more difficult to put forward their own opinions. Some maintenance personnel avoid the key positioning operation steps in order to reduce the workload when doing four-wheel alignment, which makes the positioning detection result far from the actual. In addition, there are some maintenance personnel who have no sense of responsibility. They do not perform pre-positioning inspections before doing positioning. Even the cracks in rubber bushings for half-axis rubber sleeves and lower-arm hinge joints cannot be discovered in time or users are not informed, leading to greater users in the future. Losses, repeated positioning and repeated charges. Myth #5: What kind of four-wheel locator is the same? The qualification of four-wheel alignment mainly depends on the skills of maintenance personnel and the quality of the positioning instrument. The domestic four-wheel aligner can be described as a complete range of products, ranging from low-end 20,000 to 50,000 yuan, mid-range 50,000 to 100,000 yuan, and high-end multi-million dollars. The price of low-end products is cheap, but users have more problems with their reactions: low technical content, poor accuracy, and high failure rate. The market share of mid-end products is relatively large, and it can basically meet the needs of general users. Most high-end products are high-tech imported products, some are world-famous brands, and technologies are world-class. Their positioning software and hardware are fully functional, more human-oriented and work efficiency is higher, solving more problems for enterprises and users. Not only can you achieve excellent wheel alignment, but it can also help diagnose chassis faults. Has better economic and social benefits. How to buy four wheel alignment In the domestic market, there are many kinds of wheel alignment equipment brands. Because of its relatively high technical content, many users do not understand their technical performance and measurement principles. Faced with a wide variety of product introductions by vendors, they are often at a loss when choosing equipment. Here are some suggestions for the main aspects: How to perform performance-cost ratio The price difference between different brands of four-wheel positioning is very different. As the state has no corresponding regulations for the production of four-wheel alignment products, domestic products are mixed. For example, although some brands of equipment are equipped with computers, computers use only the management functions of vehicle model data, sensors are not connected to computers, and sensor data cannot be On the computer, the user shouted after buying. Some equipment used as the banner of import to deceive users, some equipment cut corners; some manufacturers use imported low-end sensors for simple assembly, they lack the maintenance technology for sensors, so that user equipment failure can not be eliminated in a timely and effective manner: the most popular type of positioning equipment, the cheapest More than 20,000 yuan can buy, expensive equipment (generally speaking, all imported equipment) will be more than 100,000 or even hundreds of thousands. In general, a price for a goods. However, due to factors such as the existence of tariffs on the imported equipment and the increase of prices by the agents, the price is relatively high. Different brand equipments have different costs due to their advanced technology, production process, and configuration, and therefore the market sales price is also different. Technically, users can identify the technical performance of the device from the following aspects: A, whether to use DSP technology The DSP, or Digital Signal Processor, is a dedicated processor that performs high-speed real-time processing of digital signals, and its processing speed is 10-50 times faster than the fastest CPU. The early DSP was mainly used for military products. Later, with the continuous development of large-scale integrated circuits and the continuous reduction of costs, they were gradually applied to civilian products. Because DSP has powerful computation ability, after adopting DSP in the sensor, not only has improved the measurement speed of the data, measurement precision, the antijamming ability of the measurement has been improved greatly. Four-wheel positioning products using DSP have the following features: Fore beam measurement is highly resistant to light interference: Infrared or laser transceiving sensors are commonly used in four-wheel locators that use ray measurements to measure the vehicle's toe data. Since there are components in the sunlight or common light source that have the same wavelength as the measuring light, the data measured with the light will be affected by this and will deviate from the correct measurement result. For this reason, some positioning devices use filters to reduce the influence of external light, but they cannot completely eliminate the influence of external light. This is the reason why many four-wheel locators need to pull the curtains when measuring under sunlight. However, if you use the curtains to block outside light in the evening or in other weak light environments, it will not work. If DSP technology is used to modulate the measuring light line, the modulated infrared light has different characteristics from the sunlight, or light from other light sources. When receiving, the modulated measuring light is demodulated and filtered out. This ensures that The measurement results are not disturbed by other light. The cost of DSP technology equipment for DSP is higher, and the technology is advanced. Its price is relatively high. B. Whether to adopt the electronic level? In order to achieve the designed measurement accuracy, the universal four-wheel locator must ensure that the four probes are always in the horizontal state during the measurement process. Any probe's non-horizontal condition can cause erroneous measurements. For four-wheel aligners with bubble-type instructions, the operator must be very careful to note whether each probe is in a horizontal state, which not only distracts the operator's energy, but also inevitably prevents mismeasurement. If the electronic level is installed on all four probes, the horizontal status data of the sensor probe is transmitted to the computer in time. The computer monitors the horizontal data of each sensor probe and prompts the operator when the probe is not horizontal. , This not only reduces the operator's work intensity, but also easily avoids mis-measurement operations. In the imported equipment, electronic equipment is used in the positioning equipment of Hunter in the United States and Bossh in Germany, and their prices are also relatively expensive. C. Whether to use electronic turntable? In the positioning parameters, the kingpin caster angle and the kingpin caster angle cannot be directly measured. Only the indirect measurement based on the geometric relationship can be used. The left and right front wheels are rotated by 20 degrees and the camber angle and backrake angle are measured respectively. According to a certain functional relationship, the kingpin caster angle and the kingpin tilt angle are calculated. Therefore, the measurement of the kingpin caster angle and kingpin caster angle is closely related to the steering angle measurement. Steering angle When the steering angle is 20 degrees and 20.5 degrees, the relative error of the detected kingpin angle result is 2.39%, which is far beyond the requirement of the detection precision. It can be seen that the turntable error has a huge impact on the test results. Therefore, the forthcoming national industry standards stipulate: In 2005, the four-wheel locator must use an electronic corner disk. In addition, the use of an electronic rotary disk greatly improves the degree of automation of the measurement process and shortens the measurement time. Foreign high-end four-wheel locators use electronic turntables. D. Is the data communication method infrared or radio? E. Transmission technology: Radio communication equipment is more expensive than infrared transmission equipment;8 The toe system is higher than the 6 toe beam measurement system, and the electronic level is higher than the bubble level. 123 Show on this page F, measurement accuracy; G, measurement repeatability; H. Measure the reaction speed. In addition, such as equipment stability, repeatability, failure rate, maintenance prices, etc. are also very important factors, but these information is difficult to obtain correct and objective information from the manufacturer, requiring the user to obtain from the side. Service In the automobile inspection and maintenance products, the after-sales service of the four-wheel alignment device is of more important significance, and the after-sales service content is more abundant and complex. Because of its high price, after the equipment fails, it must provide timely maintenance services. Due to its high technical content, only those manufacturers with technological development strengths can provide low-price and high-quality maintenance services. For non-technical manufacturers, the replacement of large parts such as changing sensor heads and changing the main control board is often used to repair the customer's equipment. This not only results in high maintenance costs, but also makes the user unbearable, and often cannot be timely. The use of four-wheel alignment equipment is relatively complex and requires manufacturers to provide quality operational training services. For those users who are not familiar with car chassis, manufacturers must also have the ability to locate faults in the car. In addition, due to the continuous emergence of new models, manufacturers are also required to be able to upgrade the vehicle positioning data in a timely manner. In summary, the user must carefully check the after-sales service capabilities of the manufacturer in all aspects of the above before purchasing the four-wheel alignment device.