506 工程灑水車設(shè)計(jì)（五噸載重量）變速器改造設(shè)計(jì)和校核（有cad圖+中英文翻譯等）

506 工程灑水車設(shè)計(jì)（五噸載重量）變速器改造設(shè)計(jì)和校核（有cad圖+中英文翻譯等）,506,工程灑水車設(shè)計(jì)（五噸載重量）變速器改造設(shè)計(jì)和校核（有cad圖+中英文翻譯等）,工程,灑水車,設(shè)計(jì),載重量,變速器,改造,以及,校核,cad,中英文,翻譯 ? Automatic Transmissions by Charles Ofria The modern automatic transmission is by far, the most complicated mechanical component in today's automobile.? Automatic transmissions contain mechanical systems, hydraulic systems, electrical systems and computer controls, all working together in perfect harmony which goes virtually unnoticed until there is a problem. This article will help you understand the concepts behind what goes on inside these technological marvels and what goes into repairing them when they fail. This article is broken down into five sections: · What is a transmission breaks down in the simplest terms what the purpose of a transmission is. · Spotting problems before they get worse shows what to look for to prevent a minor problem from becoming major.? · Maintenance talks about preventative maintenance that everyone should know about.?? · Transmission repairs describes the types of repairs that are typically performed on transmissions from minor adjustments to complete overhauls.? What is a transmission? The transmission is a device that is connected to the back of the engine and sends the power from the engine to the drive wheels.? An automobile engine runs at its best at a certain RPM (Revolutions Per Minute) range and it is the transmission's job to make sure that the power is delivered to the wheels while keeping the engine within that range.? It does this through various gear combinations. In first gear, the engine turns much faster in relation to the drive wheels, while in high gear the engine is loafing even though the car may be going in excess of 70 MPH.? In addition to the various forward gears, a transmission also has a neutral position which disconnects the engine from the drive wheels, and reverse, which causes the drive wheels to turn in the opposite direction allowing you to back up.? Finally, there is the Park position.? In this position, a latch mechanism (not unlike a deadbolt lock on a door) is inserted into a slot in the output shaft to lock the drive wheels and keep them from turning, thereby preventing the vehicle from rolling. There are two basic types of automatic transmissions based on whether the vehicle is rear wheel drive or front wheel drive.?? ?On a rear wheel drive car, the transmission is usually mounted to the back of the engine and is located under the hump in the center of the floorboard alongside the gas pedal position.? A drive shaft connects the rear of the transmission to the final drive which is located in the rear axle and is used to send power to the rear wheels.??Power flow on this system is simple and straight forward going from the engine, through the torque converter, then through the transmission and drive shaft until it reaches the final drive where it is split and sent to the two rear wheels. ?On a front wheel drive car, the transmission is usually combined with the final drive to form what is called a transaxle. The engine on a front wheel drive car is usually mounted sideways in the car with the transaxle tucked under it on the side of the engine facing the rear of the car.? Front axles are connected directly to the transaxle and provide power to the front wheels.?In this example, power flows from the engine, through the torque converter to a large chain that sends the power through a 180 degree turn to the transmission that is along side the engine.? From there, the power is routed through the transmission to the final drive where it is split and sent to the two front wheels through the drive axles. ?There are a number of other arrangements including front drive vehicles where the engine is mounted front to back instead of sideways and there are other systems that drive all four wheels but the two systems described here are by far the most popular.?A much less popular rear drive arrangement has the transmission mounted directly to the final drive at the rear and is connected by a drive shaft to the torque converter which is still mounted on the engine. This system is found on the new Corvette and is used in order to balance the weight evenly between the front and rear wheels for improved performance and handling.??Another rear drive system mounts everything, the engine, transmission and final drive in the rear.? Spotting problems before they get worse · Watch for leaks or stains under the car If there is a persistent red oil leak that you are sure is coming from your car,? you should have your shop check to see if it is coming from your transmission or possibly from your power steering system (most power steering systems also use transmission fluid and leaks can appear on the ground in roughly the same areas as transmission leaks.)? If all you see is a few drops on the ground, you may be able to postpone repairs as long as you check your fluid level often (but check with your technician to be sure.)? If transmission fluid levels go down below minimum levels serious transmission damage can occur (the same advice goes for power steering leaks as well.)? · Check fluid for color and odor Most manufacturers require that you check transmission fluid levels when the vehicle is running and on level ground.? Pull the transmission dipstick out and check the fluid for color and odor.? Transmission fluid is a transparent red oil that looks something like cherry cough syrup.? If the fluid is cloudy or muddy, or it has a burned odor,? you should have it checked by your technician who will most likely advise you to have a transmission drain and refill or transmission tune-up. See the Maintenance section below for details on this service. · be sensitive to new noises, vibrations and shift behavior A modern transmission should shift smoothly and quietly under light acceleration.? Heavier acceleration should produce firmer shifts at higher speeds.? If shift points are erratic or you hear noises when shifting, you should have it checked out immediately.? Whining noises coming from the floorboard are also a cause for concern.? If caught early, many problems can be resolved without costly transmission overhauls.? Even if you feel that you can't afford repairs at this time, you should at least have it checked.? The technician may be able to give you some hints on what to do and not do to prolong the transmission life until you can afford the repair.?? Maintenance Transmission fluid should be changed periodically.? Your owner's manual should give you the recommended intervals which could be anywhere from 15,000 miles to 100,000 miles.? Most transmission experts recommend changing the fluid and filter? every 25,000 miles. Few transmissions have drain plugs to drain the old fluid.? In order to get the fluid out, the technician removes the transmission oil pan.? This is quite a messy job and generally not recommended for the casual do-it-yourselfer.? Even if the transmission has a drain plug, the only way to also change the transmission filter is to remove the pan. When the pan is down, the technician can check for metal shavings and other debris which are indicators of impending transmission problems. Transmission repairs. · Adjustments and In-Car Repairs There are several problems that can be resolved with an adjustment (A simple adjustment is one that can be made without removing the transmission from the vehicle.)?or minor repair. If a late model transmission (computer-controlled transmissions started becoming popular in the early '90s) is not shifting properly, it is often the result of a computer sending incorrect signals due to a faulty sensor, or the transmission is not reacting to the computer command because of a bad connection or defective solenoid pack.? These problems can be corrected while the transmission is in the car for considerably less money then a complete overhaul. If a non computer-controlled transmission is shifting too early or too late, it may require an adjustment to the throttle cable. Since throttle cables rarely go out of adjustment on their own or due to wear and tear, these mis-adjustments are usually due to other repair work or damage from an accident.? If the vehicle has a vacuum modulator instead of a throttle cable, there is an adjustment that can be made using an adjustment screw in some modulator designs.? In vehicles with modulators, however, it is very important that there are no vacuum leaks and the engine is running at peak efficiency. Engine vacuum is very sensitive to how well the engine is running.? In fact, many technicians use a vacuum gauge to diagnose performance problems and state-of-tune. Many problems that seem to be transmission problems disappear after a tune-up or engine performance related repair was completed. In some older transmissions, bands can be adjusted to resolve "slipping" conditions.? Slipping is when an engine races briefly when the transmission shifts from one gear to the next.? There are no adjustments for clutch packs however. · Reseal job A transmission is resealed in order to repair external transmission fluid leaks.? If you see spots of red oil on the ground under the car, your transmission may be a candidate for a reseal job.? In order to check a transmission for leaks, a technician will put the car on a lift and examine the unit for signs of oil leaks.? If a leak is spotted at any of the external seals or gaskets and the transmission otherwise performs well, the technician will most likely recommend that the transmission be resealed. Most of the external seals can be replaced while the transmission is still in the car but, if the front seal must be replaced, the transmission must first be removed from the vehicle in order to gain access to it, making it a much costlier job.? · Replace accessible parts There are a number of parts that are accessible without requiring the removal of the complete transmission.? many of the control parts including most of the electrical parts are serviceable by simply removing the oil pan.? The parts that are accessible, however, vary from transmission to transmission and most transmission repair facilities would hesitate to provide meaningful warrantees on external repairs for the simple reason that they cannot see if there are any additional internal problems in the components that are only accessible by transmission removal.? · Complete Overhaul In a complete overhaul (also known as rebuilding a transmission), the transmission is removed from the vehicle and completely disassembled with the parts laid out on a workbench. Each part is inspected for wear and damage and then either cleaned in a special cleaning solution, or replaced with another part depending on its condition. Parts that have friction surfaces, such as bands and clutches are replaced as are all seals and gaskets. The torque converter is also replaced, usually with a remanufactured one.? Technical service bulletins are checked to see if the auto manufacturer recommends any modifications to correct design defects that were discovered after the transmission was built. Automobile manufacturers often make upgrade kits available to transmission shops to resolve these design defects. VI