Reversing driving is used to meet the needs of the car driving backwards. To achieve reverse driving, the crankshaft of the engine can only rotate in one direction, and the automobile sometimes needs to be able to reverse the driving. Therefore, the reverse gear set in the gearbox is often used to realize reverse driving of the vehicle.
The transmission of power is interrupted, and the transmission of power to the drive wheels is interrupted when the engine is started, idling, or when the vehicle shifts gears or needs to stop for power output.
To achieve neutral, the transmission may not output power when the clutch is engaged. For example, it may be ensured that the driver releases the clutch pedal from the driver's seat when the engine is not shutting down.
Product Analysis Due to the rapid development of automobiles, the current models are also quite numerous, and the type of transmission is relatively fixed. Therefore, we have designed this platform for transmissions of common models such as trucks, mini cars, and front-drive cars. frame.
The most important part of the transmission running gantry is the interface parameters of the various transmissions, including the input shaft, transmission and engine interface parameters. The other common parts are the same. Therefore, when we perform the bench test on different transmissions, we only need to change the spline of the input shaft to perform the test.
The structure of the gantry is relatively simple, mainly consisting of the base of the gantry, the transmission positioning plate, the spline connection shaft, the shaft sleeve, the spline fixing frame, the bearing support base, the connecting sleeve, the motor fixing frame and the like. Parts need to be designed by us. Three-speed motors, bearings, positioning pins, bolts and other standard parts can be purchased on the market.
The base structure is more complex and the stability is better, so the requirements are: higher rigidity, thicker support surface and wall thickness. Commonly used materials are gray cast iron or alloy cast iron. If single-piece or small-batch production is generally expensive, but the production cycle is relatively long, we use scrap lathe bed, or use a thickness of 30 ~ 40mm. Steel plate welding. Transmission parts positioning plate, spline connection shaft, shaft sleeve, spline fixing frame, bearing support base, and motor fixing frame are relatively small. When the single piece is produced, steel plate welding and round steel can be used for secondary processing. In this case, The processing cycle is shortened and the cost is lower.
When doing the bench test, since there are many daily transmissions and about 200 units per day, the requirements for the disassembly and assembly of the transmission are convenient and flexible. The operation is simple and the connection is firm and reliable. So we took two methods. One was to hoist the transmission on top of a small car, then slide it forwards on the rails of the lathe and install it on the connecting plate. One is to use a simple crane to hang the transmission directly onto the gantry. The latter is generally used on a pedestal welded with a steel plate. After many tests, we have adopted a method of lifting directly with simple cranes, because although this method increases labor intensity, it increases efficiency and saves costs.
Process parameter design 1. The design base of the base, transmission positioning plate, motor fixing frame and other parts, whether it is used machine base or steel plate welding, in the design or processing process there is no special requirements, if the steel plate welding is required to Both sides can be roughed. The transmission positioning plate, the motor fixing frame, and the spline fixing frame are all made of welded steel plates, and 45 mm steel plates are required and then bolted to the base plate. For ease of assembly and disassembly, and accuracy of reinstallation, the positioning pin holes are machined on the transmission positioning plate, the motor fixing frame, the spline fixing frame and the base, and two positioning pin holes can be diagonally processed. Due to the relatively large vibration of the entire gantry during the run-in process, the variator requires a stiffening rib in its structure and the bolt requirement is relatively large, but a 25mm steel plate is required on the top of the transmission positioning plate and the spline fixing bracket. Fixed to prevent deformation of the transmission positioning plate due to vibration and frequent loading and unloading.
2. The choice of motor As the transmission is doing bench testing, it requires different speeds to check the performance of each gear, use low, medium and high speed gear shifts to check the flexibility of the shift, the combination of the synchronizer, Bearing quality and so on. At the same time, the tooth profile and other parameters of the gears need to be tested with three different speeds: low, medium, and high. The abnormal noise of the bearing, gear, synchronizer, and shift fork, etc., also needs to be judged using different speeds. A speed reducer or deceleration mechanism will increase the workload and increase the cost. Therefore, after we integrated various factors, we chose YD series variable speed multi-speed three-phase asynchronous motors (JB/T7127-1993).
3. The development of the process The overall process principle for the assembly and processing of the bench is based on the connection of the three-phase asynchronous motor. The bearing support and the spline holder are separately machined and connected together as a whole. Then, the transmission positioning plate, the motor fixing frame, the spline fixing frame and the like are fixed on the base, and the positioning holes are drilled and fixed with the positioning pins. After confirming that the positioning plate and the fixing frame are fastened, the center hole of the spline fixing frame and the motor fixing frame is first roughly machined and then fixed to the base, and then the φ80 bearing hole and the φ230 motor are machined. Locating holes to ensure that the coaxiality of the two is less than 0.025mm. Fix the transmission fixing plate on the base. Measure the hole φ230 and the end face with the motor mounting hole as a reference. Other parts must be firmly welded or firmly connected. The spline connection shaft is selected according to the model of the transmission. The gantry is suitable for various types of transmissions such as 465, 474, 140, 145, 6T53, and 6T90. The suspension of the transmission is installed on the guide rails and is used for mobile lifting. Different working conditions can be used for different lifting methods. Our company is a heavy-duty production crane that uses a fixed rail to lift.
4. The choice of materials The base can use scrap lathe base, 45mm thick A3 steel plate. Transmission detents, splined shafts, bushings, spline holders, bearing supports, coupling sleeves, motor mounts, etc., due to high stiffness requirements, so when selecting materials should choose some high-quality steel, such as the 45th steel. The assembly diagram is shown below. Spline connection shaft and transmission fixing plate hole are to be quenched and tempered, hardness requirements are: HRC38-42.
Concluding remarks The gantry has simple processing technology, wide application range, easy material selection, low material requirements, strict requirements on heat treatment, and can use scrap lathes and other reclaimed parts as the base. Professional manufacturers or maintenance companies can use. After the gantry was used by Hepu Gear Factory, Guilin Wuling Transmission System Co., Ltd., and Liuzhou Qingshan Transmission Company, the reaction was very good and was highly praised by the manufacturers.
Nantong Tobel Intelligent Controlling Equipment CO;LTD , https://www.tobel-tech.com