Step 1: Idling support combination (heart part-engine hydraulic pressure)
1. Small digging bulldozer shovel: Set the throttle to the lowest, idle shovel bulldozer, while the small throttle shovel looks at the revolution meter and exhaust conditions. For small digs weighing less than 10 tons. If it is normal for the shovel to easily top the car while the engine is rotating at 100-200, then the performance is basically good. On the contrary, if the equipment is easily annihilated, or the rotation is beyond 200 rpm, the engine shakes badly, indicating that the force is not very large, and the pressure of the engine and the large pump do not match.
2. Idle boom truck: Put the big and small arms of the excavator to the lowest position, flip the bucket out, touch the ground with a horse head, and pull the top of the horse head to see if it can be jacked up (Note: Small digging in Xiaosong 56 , Kubota series cannot be supported due to the car's own design). Just like a bulldozer, there is no bulldozer as a big dig. You can cooperate with this action. The force of the big arm truck is very large. When the watch looks at the engine speed table at the same time, the idle speed of the big dig is usually 1000. Turn around, the car can be turned between 100-200. If the idle speed cannot be supported and the engine speed exceeds a large range or annihilates, it means that the engine power of the excavator does not match the pressure of the large pump and there is severe wear. Performance can be judged accordingly.
3. Idling limit action car: The big and small arms are raised to the highest level, and the bucket receives the lowest. Once idling and once with high throttle. Cooperate with the car while observing the engine rotation and engine exhaust color.
Use small and large accelerators, small dig: standard idling at 900 rpm, normal rotation at 100-200, maximum throttle no more than 300; large dig: 1000 rpm, idling at 100-200 normal (within 200 rpm: any excellent performance engine) (At high speed overflow, the rotation is within 200 rpm).
The above three points mainly determine whether the engine power matches the pressure of the hydraulic pump and whether the oil circuit is smooth. The three movements need to be interspersed with each other to operate. All of them mentioned the number of revolutions and the car. In the actual operation of the excavator, if these data and conditions are not up to standard, the equipment will turn when it digs hard things, or Will be annihilated, commonly known as the car, if the performance is not good, it can not be competent for excavation work for a long time.
Step 2: Wear clearance of each part (joint part-working device clearance)
1. The wear of the working device gap lifts the excavated large and small arms to the horizontal position and rotates left and right. The main observations are three positions:
① Clearance between horse head and forearm;
② clearance between forearm and forearm;
③ Clearance between boom and main frame.
The two gaps ① and ② are normal if they are not very large. Because we know that normal excavators work, iron and iron friction must be worn, mainly depending on the gap between the boom and the main frame. If this gap is large, the car will be worn out and the maintenance will be poor. Or it will have a great impact if you bring it over.
2. Cylinder gap wear: The big and small arms are flattened and the bucket is gently lifted to see the gap between the heads of the big arms, the two arms and the buckets. The smaller the clearance, the lighter the wear is, and the better the lubrication is (more buttery). If the clearance is large, the wear will be more serious, the lubrication will be poor (don't take care of maintenance), or the hammer will be more.
Both the big and small arms and the oil cylinder are relatively important working devices. The combination of several actions can be used to analyze the maintenance status and specific working intensity of the excavator.
The third step: test the clearance of the rotating disk and the rotating deceleration (waist part-rotating deceleration disk X frame)
1. Test the gap between the upper and lower plates: lift the bulldozer and place the excavator in a horizontal position. Raise your big arm and zoom in. Increase the frequency and speed so that the upper and lower parts of the excavator shake. People squat in the middle of the market to observe the gap between the upper and lower sides of the market. If the gap is too large, the car's disk is relatively worn. The excavator that hits the breaker for a long time is the most obvious. Due to the pressure transmission from the breaker to the large pump and the severe vibration from the top to the bottom, the gap between the top and bottom of the disk is too large. Serious conditions will affect the normal work of the excavator and need to be repaired. (Example: For some municipal greening projects, for example, the leveling of the land is very demanding. When working, the violent shaking of the market will cause the cab to shake, and the driver sitting in the cab operating the pilot handle will accompany the slight shaking and leveling. Difficulty exists, it is recommended to use a dial indicator to measure the turntable bearing).
2. Test the gap between the left and right sides of the market: Idle speed, turn it gently, if the excavator rotates immediately, it proves that the gap is small. On the contrary, there will be a few seconds of dullness after clicking, indicating that the gears are worn seriously, the reduction gears are stuck or the gap is too large, and the gears do not bite; you can also raise the boom of the excavator, the two arms vertical to the ground, and gently Take a look back at the gap.
3. Test whether the slewing brake is overtravel: idle speed, maximum throttle and minimum throttle are tested separately. Suddenly stopped during the left and right rotation, to see if the excavator rotation can stop, usually the excavator has a certain brake protection and a small buffer when the rotation is stopped. However, if the deceleration overtravel is too large to be controlled, it will affect work. (For example: if the excavator is engaged in loading or dumping earth, excessive deceleration and overtravel will throw the material outside the specified range. It will increase the difficulty for the driver to operate the excavator).
4. Listen to whether there are abnormal noises from the motor and deceleration in the combination of three actions: When doing the above actions, listen to whether there are abnormal noises from the motor and rotation deceleration.
Rotary deceleration and reload motors are important as the waist of the excavator, and the cost of maintenance is high. The performance tests of the above four actions are reflected in the detection process. For example, we will use a dial indicator to measure the upper and lower gaps of the disk, which is accurate to a few tenths of a millimeter.
Step 4: Chassis test (lower limbs and feet-four-wheel belt)
1. Check whether the unilateral walking is strong at idle: Move the left walking control handle at idle to see if it can rotate in place, otherwise test the right. This action can test not only the strength of the walking motor, but also the power of the engine and the walking motor. If it is not moving or extinguished, the power is not matched, or the motor is faulty.
2.Whether the deviation is walking: Place the excavator in a horizontal position and push the walking rod to see if it is straight. If you just run away, it means that the motors on the two sides are not the same as each other or the pump valve gives uneven flow to the two motors. In severe cases, maintenance is required.
3. Walking speed: Commonly known as the turtle and rabbit gear, press and hold the switch to debug during walking. Example: The excavator needs fast gear for walking under special conditions. No fast or slow gear will affect the speed and efficiency of work.
4. Chassis consumable inspection: After completing the above three actions, support the car with a big arm and a bulldozer, and watch the chain plate, chain bar, chain bone (chain link), roller, drag chain, drive Wear of chassis components such as teeth. Close the key door, keep the cart in the state, and check whether the pressure of several cylinders is relieved.
Step 5: Degree of action matching: (brain part-main control valve)
The degree of action matching is commonly known as the work action. We try to make the following action combinations.
1. Demonstrate a set of car actions (bucket, big and small arms, turning combination to see if the work is smooth);
2. Perform actions while walking (do basic movements in walking mode to see if they are stuck);
3. Rotating large disk of the top car (swing combination big and small arms).
Through this series of action combinations, we can judge whether the car's actions match and whether the main valve is stuck. At the same time, the sensitivity of each action can be considered from the side. Engine power, hydraulic pump flow, walking motor, deceleration, and rotary motor deceleration can be coherent, and the performance of the excavator can be judged comprehensively.
