Application of Wheel Side Reduction System on Komatsu Series Excavators
Hydraulic pump is the power source of used komatsu excavator hydraulic system, it is the energy conversion device that converts mechanical energy into hydraulic energy. Hydraulic pump in the hydraulic excavator is also the most faulty components, and once the hydraulic pump failure will immediately affect the normal work of the excavator hydraulic system, or even can not work!
1, gear pump common failure, most of them are caused by the wear of its internal friction vice. Its normal wear and tear so that the radial clearance and axial clearance (i.e., section clearance) increases, so that the gear pump internal leakage phenomenon is aggravated, and in severe cases, the pump body hole or both sides of the plate can not be repaired. In addition, the shaft seal is also often damaged parts.
2, vane pumps and gear pumps are different, its normal wear and tear is very small, long service life of parts. The main cause of vane pump failure is oil contamination, this is because the vane pump sports vice with more precise, when the pollutant into the friction vice, easy to produce abnormal stall or wear. In addition, the self-priming performance of the vane pump is not as good as the gear pump, especially the small displacement vane pump is more so, so whether the oil is clean and suction is smooth, is the vane pump operation needs special attention to the two problems.
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3, the radial piston pump in the structure and performance of the movement of the piston pump in the structure and the weakness of the radial force is larger, less self-absorption ability and the plunger and the plunger hole with high precision; axial piston pump parts machining accuracy requirements are high. Therefore, piston pumps require high cleanliness of the oil, that is, piston pumps require higher filtration accuracy of the oil than gear pumps.
Product Structure Wheel Side Reduction System on Komatsu Series Excavators Huaiyin Institute of Technology Tan Guochen Chen Yong Excavators.
The excavator wheelside reduction system uses a cycloid pinwheel reduction device, also known as differential planetary gear reduction device. Its structure and similar reduction device compared to more special, the deceleration process for the hydraulic motor input power by spur gear stage deceleration to the crankshaft, the crankshaft and then drive the circumferential cycloid gear for eccentric movement, by the circumferential cycloid gear drives the pin type hub will be the power output. The device consists of a reduction system and a braking system.
2 deceleration system the deceleration system consists of two parts of the first part of the wheel system deceleration mechanism, which consists of spur gears; the first part of the eccentric deceleration mechanism, which consists of a crankshaft group of a total of six eccentric wheels and the installation of its two weeks on the cycloid gears 8 and pin-type hubs, known as the stage reducer, whose role is to decelerate the high-speed movement of the stage deceleration, transformed into a low-speed high torque to drive the excavator travelling device.
2.1 stage reducer hydraulic motor slewing motion through the input gear to its meshing with a spur gear, driving eccentric crankshaft for deceleration slewing, such as the transmission ratio is calculated according to the following formula service zi input shaft spur gear teeth 2.2 stage reducer wheel and 3 to the crankshaft rotating centre for the eccentric rotation of the rotary axis and relative to the crankshaft of the rotational axis, due to the root of the crankshaft of an eccentric wheel at the same time through the circumferential swing gears, and therefore, the circumferential swing gears into the work The trajectory is a circle with the centre of rotation of the crankshaft as the centre of the circle and the eccentric wheel eccentricity as the radius of the translational movement. Similarly, the peripheral oscillating gear 8 performs the same translational movement as the product structure. The two eccentric wheels on the same axis rotational direction is the same, the phase difference of 180., its purpose is to improve the transmission of the balance performance and force conditions. Weekly cycloid gear liver and how to 8 and eccentric crankshaft eccentric crankshaft spur gear rotation direction is the same, and its translational cycle for eccentric crankshaft spur gear rotation cycle.
Weekly pendulum gear and 6 for eccentric movement, 1 into and only 8 of the tooth surface will side along the often meshing pin rolling, side in order to change the meshing point pin will be to the hub gear ring pin number B and weekly pendulum gear teeth number B between the difference usually difference for for the public rotation movement. The weekly cycloid gear translates 1 week, the pin rotates around the input shaft of the stage for a week, and this pin rotation is transmitted to the hub, driving the hub to make a deceleration slew. Stage reduction transmission is calculated according to the following formula zx number of pins zr number of weekly cycloid gear teeth total transmission ratio 1 calculated as the following stage reduction transmission 3.
3 Brake system The brake system is installed on the left side of the hydraulic motor, which consists of a bit pass hydraulic brake valve and disc brake. It consists of a bit pass hydraulic brake valve and disc brake. Its working status is as follows 3.1 brake release motor operation through the left control port to push the slide valve to the right, the slide valve left position work, 1 when the oil circuit shunts out of the pressure oil to make the brake away from the hub, lifting the braking 2 force, at the same time, the pressure oil into the motor's left inlet, so that the hydraulic motor rotary. When oil enters the 8 port, the slide valve moves to the left and the motor reverses.
3.2 Brake work motor stops when the population stops supplying oil, the left side of the oil circuit oil pressure disappears, is on the right side of the slide valve back to the neutral position, at this time the hydraulic motor has no driving pressure oil, due to the inertia of the vehicle and other reasons, the hydraulic motor is still rotating.
The oil discharged from the hydraulic motor has no oil leakage path, and the outlet oil pressure rises suddenly, and the high-pressure oil pushes away the buffer valve on the right side, and flows into the left oil circuit through the check valve on the left side, preventing the left oil circuit from generating air pockets. At the same time, due to the oil pressure to the brake is cut off, the brake hydraulic cylinder under the action of the spring force to restore to the wheel hub 3.3 brake work speed-limiting motor speed-limiting operation downhill, due to the reason of the ramp will make the vehicle speed faster, the hydraulic motor to do the over-speed movement, that is, the displacement of the hydraulic motor is greater than the hydraulic pump oil supply. Source China Used Excavator Market https://www.lh-usedexcavator.com/
