How to adjust the excavator crawler for the best performance and maintenance of an excavator&#;

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The excavator crawler plays a crucial role in moving materials and overburden, before the machine goes ahead to dig up the soil. The speed of the machine and its performance depend on how well it is maintained. Let&#;s know about those maintenance procedures in detail!

What is the function of excavator crawler?

The excavator crawler is the moving part on an excavator that helps the machine move faster and dig deeper into the ground. It is also used to remove rocks, dirt, and other material from the excavation site. To ensure optimal performance and maintenance, it is important to adjust the crawler for the best performance.

How to adjust the excavator crawler for the best performance and maintenance of an excavator&#;

The crawler on an excavator is the part that helps the machine move around the ground. It has four or six wheels that are connected to a motor, and it moves along the surface of the ground. The crawler is adjustable to allow for different levels of performance and maintenance.

Types of Excavator Crawler Tracks

There are three types of crawlers on excavators- track, bucket and claw. Each crawler has different purposes and is adjusted for the best performance and maintenance.

A track crawler moves along the ground using tracks that run between the front and rear wheels. It is used for moving material around the excavation site.

A bucket crawler uses a series of buckets that are suspended from the front or back of the machine. The buckets move along a track in sync with the machine&#;s movement, transferring material to the front or back of the excavator.

Claw crawlers use a series of claws to grasp and move objects. They are often used to remove large objects from an excavation site.

Maintenance of a crawler on an excavator

An excavator crawler is the main component of the machine that helps it move through the soil or other material. It also helps the excavator to lift and transport material. Crawlers are usually adjustable to allow for varying ground conditions and are usually lubricated to help reduce friction.
Crawlers can become misaligned or damaged over time, requiring adjustment or replacement. Here is a guide on how to adjust a crawler on an excavator:

1&#;Position the tracks on the excavator. It should be in front of the blade and under the platform.

2) Loosen the adjusting screw at the front of the crawler with a wrench. This will allow you to make adjustments to the alignment of the crawler and excavator.

3) Align the front of the crawler with the blade on the excavator and tighten the adjusting screw.

The basic structure and working principle of the excavator for beginners guide

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Hello family of Accesorio Maquinaria ! I am your Kenway.

This week I have prepared a beginner&#;s guide to the basic structure and operating principles of excavators. In this blog post, you will learn the following.

• Chapter 1: Overview
• Chapter 2: Work Devices for Excavators
• Chapter 3: Excavator Slewing Device
• Chapter 4: Excavator Turntable Layout
• Chapter 5: Excavator Travel Devices

It is very informative and I think you will have a clear understanding of excavators by the time you finish reading it.

Chapter 1: Overview

01.The general structure of a single bucket hydraulic excavator

The general structure of a single bucket hydraulic excavator includes power unit, work unit, rotating mechanism, operating mechanism, transmission system, traveling mechanism, auxiliary equipment , etc.

Commonly used full swing hydraulic excavators have the power unit, the central part of the transmission system, the swing mechanism, the auxiliary equipment, and the cab mounted on a turntable, usually called an upper turntable. Therefore, the single bucket hydraulic excavator can be summarized into three parts: working device, upper turntable and driving mechanism.

Excavator is through the diesel engine to convert the chemical energy of diesel into mechanical energy, by the hydraulic piston pump to mechanical energy into hydraulic energy, through the hydraulic system to the distribution of hydraulic energy to the application of components (hydraulic cylinder, rotary motor + reducer, walking motor + reducer), by the application of the components, and then the hydraulic energy into mechanical energy, to achieve the movement of the working device, the rotation movement of the platform , the whole walking machine.

02.Power systems for excavators

• Excavator power transmission lines
• Travel power transmission path: diesel engine &#; coupling &#; hydraulic pump (mechanical energy into hydraulic energy) &#; distribution valve &#; &#; central rotary joint &#; travel motor (hydraulic energy into mechanical energy) &#; reducer &#; drive wheel &#; tracks chain &#; to achieve gait.
• Swing motion transmission path: diesel engine &#; coupling &#; hydraulic pump (mechanical energy into hydraulic energy) &#; distribution valve &#; swing motor (hydraulic energy into mechanical energy) &#; gearbox &#; swing bearing &#; to achieve swing .
• Dynamic arm movement transmission path: diesel engine &#; coupling &#; hydraulic pump (mechanical energy into hydraulic energy) &#; distribution valve &#; dynamic arm cylinder (hydraulic energy into mechanical energy) &#; to achieve dynamic arm movement.
• Bucket rod movement transmission path: diesel engine &#; coupling &#; hydraulic pump (mechanical energy into hydraulic energy) &#; distribution valve &#; &#; bucket rod cylinder (hydraulic energy into mechanical energy) &#; to get the bucket rod movement saucepan.
• Bucket movement transmission route: diesel engine &#; coupling &#; hydraulic pump (mechanical energy into hydraulic energy) &#; distribution valve &#; bucket cylinder (hydraulic energy into mechanical energy) &#; to get the bucket movement.

1. guide wheel; 2. central rotary joint; 3. check valve; 4. final drive; 5. drive motor; 6. hydraulic pump; 7. engine; 8. travel speed solenoid valve; 9. swing brake solenoid valve; 10. turning motor; 11. turning mechanism; 12. swing bearing.

03.Power unit

• The power unit of single bucket hydraulic excavator is mostly vertical multi-cylinder diesel engine; water cooled; one hour of calibrated power.

04. Drive Train

• A single bucket hydraulic excavator transmission system transmits the output power of the diesel engine to the working device, rotary device, walking mechanism, etc.
  There are many hydraulic transmission systems for single bucket hydraulic excavators, which are usually classified according to the number of primary pumps, the manner of power regulation, and the number of circuits.
  1.Single pump or single circuit double pump quantitative system 2.Double
  circuit double pump
  quantitative system 3.Multi-pump multiple circuit quantitative system 4.Double loop
  double pump variable power regulation system
  dual pump total power regulation variable
  6.Quantitative or variable multi-pump mixed system and so on six types.
  According to the oil circulation method, it is divided into an open system and a closed system; According to the oil supply method, it is divided into series system and parallel system.

1. transmission disc; 2. coil spring; 3. stop pin 4. friction plate 5. shock absorber assembly 6. muffler 7. rear engine mount 8. front engine mount.

The output flow rate of the main pump is a fixed value of the hydraulic system for the quantitative hydraulic system; on the contrary, the flow rate of the main pump can be modified by means of the adjustment system called variable system.

For more information, please visit dump truck automatic transmission.

In the quantitative system, each executive element works according to the fixed flow rate supplied by the oil pump without overflow, and the power of the oil pump is determined by the fixed flow rate and the maximum working pressure; In the variable system, the most common is the double circuit double pump constant variable power system, and there are variable power points and variable total power.

A split variable power regulation system is installed in each circuit of the system, respectively a constant variable power pump and a constant power regulator, the engine power is equally distributed to each oil pump; The full power regulation system is a constant power regulator at the same time controlling the flow changes of all oil pumps in the system, so as to achieve synchronous variable.

The return oil from the driving element in the open system flows directly back to the oil tank, which is characterized by simple system and good heat dissipation. However, the tank capacity is large, the low-pressure oil circuit is more likely to come into contact with air, and the air is easy to enter the pipeline, causing vibration.

The operation of a single bucket hydraulic excavator is mainly the work of the cylinder, and the difference of the large and small cylinder cavity is significant, frequent work, heat generation, so the vast majority of the hydraulic excavator single bucket open system; the closed circuit of the drive element return oil circuit is not directly back to the tank, which is characterized by compact structure, small tank volume, a certain pressure in the return oil circuit, the air is not easy entering the pipe, the operation is relatively smooth, avoiding the impact when changing direction.

However, the system is more complex, with poor heat dissipation conditions &#;single bucket hydraulic excavator rotation device and other local systems, and the use of a closed-loop hydraulic system. In order to supplement the hydraulic motor oil leakage back and forth, the closed system is often equipped with a filling pump.

05.Turning mechanism

• The swing mechanism allows the work unit and upper turntable to swing left or right to dig and dump material. The swing device of a single bucket hydraulic excavator should be able to support the turntable on the frame, not tilt, and make the swing light and flexible. For this reason, single bucket hydraulic excavators are equipped with swing support devices and swing transmission devices, which are called swing devices.

1. brake; 2. hydraulic motor; 3. planetary gear reducer; 4. rotating crown; 5. lubricating oil cup; 6. center swivel joint.

Hydraulic excavator full rotary device drives direct transmission form and indirect transmission of two types.

• Direct Drive: On the output shaft of the low-speed, high-torque hydraulic motor installed on the drive pinion, it meshes with the rotary gear.
• Indirect transmission: by the high-speed hydraulic motor through the gear reducer to drive the rotary gear ring, the indirect transmission structure forms. It has a compact structure with a large transmission ratio, and the gears of the force situation are better. Axial piston hydraulic motor and the same type of hydraulic oil pump structure are the same. Many parts can be standard and easy to manufacture and maintain, reducing costs. But it should be equipped with a brake to absorb the most significant rotational moment of inertia, shorten the excavator&#;s operating cycle time, and improve production efficiency.

06.Scroll mechanism

The displacement mechanism supports the entire mass of the excavator. It accomplishes the task of moving, for the most part, using tracks and tires.

• Track displacement mechanism: The basic structure of the track travel mechanism of a single bucket hydraulic excavator is approximately the same as that of other track mechanisms. However, it mainly uses two hydraulic motors to drive one track each. Like turning device drive, small torque high speed motor or high torque low speed motor is available. Two hydraulic motors rotate in the same direction, the excavator will travel in a straight line; If only one hydraulic motor is fed with oil and the other hydraulic motor is braked, the excavator will rotate around the track on the brake side. The excavator will turn on the spot if the left and right hydraulic motors turn in the opposite direction.
• Each part of the travel mechanism is mounted on the integral frame of the implement. The pressurized oil input from the hydraulic pump enters the running hydraulic motor through the multi-way reversing valve and the central rotary joint, which transforms the hydraulic energy into output torque and then transmits it to the driving wheel. through the gear reducer. Finally, wind up the caterpillar to make the bulldozer run.
• Most single bucket hydraulic excavators use combined structure tracks and flat tracks, without prominent track spurs, poor adhesion performance, but solid and durable, less destructive to the road surface for complicated rocky terrain operations or operations. frequent traffic. There are also three-spur tracks, which have a larger footprint and shallower spur depth of the tracks that cut into the ground, suitable for excavator quarry operations. After standardization, excavators must use light, high-strength and simple structures, and reduce the price of laminated track plates. The triangular track plate, specially designed for swampy terrain,
  The drive wheels of the single bucket hydraulic excavator are all made of integral castings, which can engage with the tracks properly and drive smoothly. The sprocket should be located at the rear when the excavator is running so that the track tension section is shorter to reduce frictional wear and loss of track power.
• Each track is equipped with a tensioning device to adjust the tension of the tracks to reduce vibration, noise, friction and power loss. At present, single bucket hydraulic excavators use a hydraulic tension structure. The hydraulic cylinder is placed inside the damping spring to reduce the size of the structure.

1. guide pulley; 2. track frame; 3. carrier pulley; 4. final transmission; 5. support pulley; 6. caterpillar plate; 7. center guard; 8. tension spring; 9. front guard.

• Tire travel mechanism: The tire excavator travel mechanism is composed of mechanical and hydraulic transmission. Among them, the walking mechanism of the pneumatic excavator with hydraulic transmission is mainly composed of frame, front axle, rear axle, drive axle, and hydraulic motor.
• A running hydraulic motor is installed in the gearbox fixed with the frame, the power through the gearbox, the drive shaft to the front and rear drive axle, and some excavators drive the wheels by the drive side reducer. the wheel. The use of high-speed hydraulic motor transmission method is reliable, eliminating the vertical dynamic shaft mechanical transmission of the upper and lower gearbox, simple structure, and convenient layout.

1. rack; 2. rotating bracket; 3. center swivel joint; 4. stabilizers; 5. rear axle; 6. drive shaft; 7. hydraulic motor and gearbox; 8. front axle.

Chapter 2: Work Devices for Excavators

There is a wide variety of working devices for hydraulic excavators (up to more than 100 types). Currently, the most used in engineering and construction are backhoes and crushers.

• Backhoe Structure: The articulated backhoe loader is the most common structure for a single bucket hydraulic excavator. The main parts, such as the mobile arm, the bucket bar and the bucket, are jointed with each other. Each part rotates around the hinge point under the action of the hydraulic cylinder to complete the digging and lifting and dumping action.

1 &#; bucket rod cylinder; 2 &#; mobile arm; 3 &#; hydraulic line; 4 &#; mobile arm cylinder; 5 &#; saucepan; 6 &#; bucket teeth; 7 &#; side teeth; 8 &#; connecting rod; 9 &#; rocker; 10 &#; bucket cylinder; 11 &#; bucket rod.

mobile arm

The swing arm is the main part of the backhoe loader, and its structure consists of two types: integral and combined .

• Comprehensive Boom: The advantage of an integral boom is its simple structure, light weight and high rigidity. The disadvantage is that there are fewer working devices to replace, and versatility is poor, so it is mainly used in excavators with similar long-term operating conditions. The integral movable arm can be divided into straight movable arm and bending movable arm. Among them, the straight swing arm is simple in structure and light in mass, and convenient in manufacturing, it is mainly used for suspension excavators, but it cannot be used for general excavators to obtain greater digging depth; the bent mobile arm is currently the most used form of the structure,
• Combination boom: The combination boom has an auxiliary link (or hydraulic cylinder) or a pin connection. Auxiliary linkage or hydraulic cylinder can adjust the angle between upper and lower swing arm. The advantage of the combined boom is that the working size and digging capacity of the excavator can be adjusted at will according to the operating conditions, and the adjustment time is short. In addition, it has more interchangeable working devices, which can meet the needs of various operations and are easy to load and carry. The disadvantage is that the mass is large, the manufacturing cost is high, and it is used in small and medium-sized excavators.

Cube

The longitudinal profile of the bucket must be adapted to the excavation process of various materials in the bucket movement pattern to favor the flow of materials, so that the load resistance of the soil is minimal and favors the filling of the bucket.

Bucket teeth are installed to increase the linear pressure ratio of the bucket to the excavated material. Bucket clamping and bucket shape parameters have small unit shear strength, which is convenient for cutting and breaking soil. Bucket teeth because it is loaded bucket materials are not easy to fall off, bucket models and materials easy to unload net, shorten unloading time, and improve the efficiency of bucket volume.

The shape and size of the structure backhoe bucket are closely related to the object of its operation. In order to meet the needs of various excavator operations, a variety of buckets can be configured on the same excavator. 2&#;3 and 2&#;4 show the basic and standard buckets, and the bucket teeth are assembled in the form of rubber pins and screw connections.

The bucket is connected to the hydraulic cylinder in the form of a four-link mechanism and a six-link mechanism. The four-link mechanism connects the bucket directly to the hydraulic cylinder, which makes the bucket swing angle smaller and the working torque more variable; the six-link mechanism is characterized by a more significant turning angle of the bucket after the same piston stroke of the hydraulic cylinder. Improves the transmission characteristics of the mechanism.

Chapter 3: Excavator Slewing Device

rotating device

The upper turntable is one of the three main components of a hydraulic excavator. In addition to the engine, hydraulic system, driver&#;s cab, counterweight, fuel tank, etc., there is an important part in the turntable &#; the rotating device. The hydraulic excavator slewing device has a swivel platform, a swivel bracket and a swivel mechanism. The outer seat of the rotary device is connected to the turntable with bolts, the inner seat with teeth and the bottom frame with bolts, with a rolling body between the inner and outer ring. vertical load, the horizontal load and overturning moment of the excavator working device acting on the turntable are transmitted to the undercarriage through the outer seat ring, rolling body and inner seat of the turntable. The turntable housing is attached to the turntable. It engages with the ring on the inner ring of the turntable through a pinion gear. The pinion can rotate around its axis. It can also rotate around the center line of the turntable when the return mechanism works as a base frame rotation. The pinion can rotate around its axis. It can also rotate around the center line of the turntable when the return mechanism works as a base frame rotation. The pinion can rotate around its axis. It can also rotate around the center line of the turntable when the return mechanism works as a base frame rotation.

The turning device of the hydraulic excavator must support the turntable on the fixed part (undercarriage). It cannot tip over and should make the turn light and flexible. For this reason, hydraulic excavators are configured with a swing support device (to play a supporting role) and a swing transmission device (to drive the rotation of the rotary table) and are collectively referred to as the swing device. of the hydraulic excavator.

Main Structural Shapes of Slewing Bearings

• Slewing column type slewing bearing: the oscillating hydraulic motor is driven slewing column type bearing. It is composed of upper and lower support shafts 4 and 6 fixed on the slewing body 1, upper and lower shaft seats 3 and 7. The bearing seat is fixed on frame 5 with bolts. The rotary body and the support shaft form a rotating column inserted into the bearings of the bearing seat. Housing fixed in rack 5, swing hydraulic cylinder output shaft into the lower support shaft 6, drive the rotary body relative to the rack rotation. The rotating body is often made of a &#;&#;&#; shape to avoid collision with the rotary mechanism. The working device is hinged on the rotary body and the rotary body together with the rotation.

• Roller slewing bearing: The bearing type slewing bearing is a large diameter bearing. The most significant difference between it and the standard bearing is its low speed. The turning speed of the excavator is between 5~11r/min. In addition, the available bearing race center diameter and height ratio of 4 ~ 5, while the rotary bearing is up to 10 ~ 15. Therefore, the rigidity of this bearing is poor. Work to rely on the support connection structure to secure.
• The typical structure of the slewing bearing is shown in the figure. The inner or outer seat ring can be machined into an inner or outer gear ring. The seat ring with teeth for the fixed circle, with the distribution of the screws along the circumference 4, 5 fixed on the base. Toothless seat ring is a swivel ring connected to the excavator turntable with bolts. In assembly, the seat ring 1, 3 and the running body 8 can be installed as a whole part first, and then assembled with the excavator. In order to ensure flexible rotation and prevent sticking after thermal expansion, the swivel bearing must leave a specific axial clearance. This clearance varies due to manufacturing errors and the raceway, as well as the wear of the rolling body. Therefore, between the two-seat ring with the adjusting wedge 2, assembly and repair can adjust the clearance. The insulation body 7 prevents extrusion between the adjacent rolling body 8, reduces wear of the rolling body, and performs a guiding function. The rolling body can be a ball or a roller.

• The bearing type swivel support mechanism is widely used in full-rotation hydraulic excavators, it is developed on the basis of the standard bearing, and the structure is equivalent to the enlarged bearing. It has a number of advantages compared with the traditional bearing, such as small size, compact structure, large bearing capacity, small rotary friction resistance, small clearance between rolling body and track, convenient maintenance, the long service life, the ease of performing three Etc. It has its characteristics compared with the standard bearing: the stiffness between the inner and outer seat ring of the standard bearing is based on the mounting between the shaft and the bearing seat to ensure , while it has a turntable and bottom frame to secure; Low-speed rotary support, usually withstand axial load, so the number of cycles of the contact points on the track is less.

Chapter 4: Excavator Turntable Layout

turntable construction

The central load-bearing part of the turntable is the main beam 3 of the phase frame structure with high torsional and bending stiffness welded by steel plates. The mobile arm and its hydraulic cylinder rest on lug 1 of the main beam. Large excavators use double lugs for arm support, while small excavators use single lugs. Beneath the main beam are the sleeve and support ring 2 and the left swivel bearing connection. The right side is welded with a small frame, as part of additional load support.

There should be enough rigidity at the rotary table support to ensure the regular operation of the slewing bearing. As shown in the figure.

(a) double shank lugs (b) single shank
lugs 1. lugs; 2. support rings; 3. longitudinal beams;

Turntable layout

When the hydraulic excavator is working, the location of the combined weight of the top of the turntable and the load is often shifting and tilts to the side of the load.

The hydraulic excavator layout principle is the left and proper symmetry, as far as possible to achieve a balanced mass, the heaviest assemblies and components near the end of the turntable. In addition, the coordination of the work of each device, the ease of maintenance, etc. must be taken into account. Sometimes the turntable arrangement is limited by the size of the structure. The center of gravity deviates from the axis, resulting in unequal grounding ratio of the left and right tracks, which affects the structural strength of the frame and the driving performance of the excavator, and can be solved by adjusting the counterweight center of gravity.

Determine the location of the counterweight arrangement principle to make the heavy load of the excavator, a large upper turntable operation combined force FR eccentric distance e, and its small amplitude without load combined force FR &#;s eccentric distance e&#; approximately equal.

Chapter 5: Excavator Travel Devices

Because the walking device has two main functions of supporting and operating the hydraulic excavator, the walking device of the hydraulic excavator must meet the following requirements:
Because the walking device has two primary functions of supporting and operating of the hydraulic excavator, so the walking device of the hydraulic excavator must meet the following requirements:

1. It must have significant driving force to enable the excavator on soft, wet, or uneven ground, and other poor walking with good through performance, climbing performance, and steering performance.
2. On the premise of not increasing the height of the walking device, the excavator has ample ground clearance to improve its off-road performance on uneven terrain.
3. The walking device has a larger bearing area or lower ground pressure to improve the stability of the excavator.
4. The excavator on the slope down does not occur when the slope slippage and overspeed phenomenon, to improve the safety of the excavator.
5. The size of the walking device should be in line with the road performance requirements. Hydraulic excavator walking devices, according to the structure, can be divided into two categories: crawler and tire.

The crawler moving device is characterized by strong driving force and light linkage ratio pressure, so off-road performance and stability are better, climbing ability and turning radius are small, flexible and suitable for using the crawler moving device on the hydraulic excavator in the most common applications.
However, the manufacturing cost of the crawler device is high, the running speed is low, and the running and steering energy-consuming parts wear out quickly, so the long-distance excavator with the help of other vehicles of operation.
Compared with the caterpillar type, the advantage of the pneumatic type walking device is that it runs fast, has good mobility, and does not damage the road when running, so it is prevalent in urban construction. The disadvantage is that the landing ratio is large, the climbing ability is small, and the excavator needs to be supported by particular legs when operating to ensure the stability and safety of the excavator.

When the excavator is running, the drive wheel generates a pulling force on the right side of the track &#; the drive section and the link section &#; in an attempt to pull the track out from under the support wheel, as there is sufficient adhesion between the track under the support wheel and the ground. Track start-up is prevented. The drive wheel is forced to roll the track, and the guide wheel sets the track on the ground so that the excavator moves along the track with the help of the support wheel.

In the hydraulic drive crawler running device, when the excavator rotates, there are two hydraulic pumps mounted on the crawlers respectively to supply oil to the running motor through the oil circuit control; it is very convenient to realize on-site turning and turning, in order to adapt to the excavator in a variety of terrain, site movement. The figure shows the turning situation of the hydraulic excavator. Figure (a) shows the two travel motors turning in opposite directions and the excavator turning in place. Figure (b) shows that the hydraulic pump only supplies oil to a travel motor, and the excavator rotates around a measuring track.

Structure

Movable structure
The walking frame is the load-bearing skeleton of the crawler running device, which consists of the bottom frame, the cross member, the beam and the crawler running frame.

The walker can be divided into combined type and integral type, depending on the structure. The bottom frame of the combined walker is the frame structure. The cross beam is an I-beam or welded box beam inserted into the hole in the track frame. The running frame usually adopts the open bottom section in the shape of &#;pi&#;; the two ends are fork-shaped to install the drive, guide and support wheels.

The advantage of the combined running frame is that when it is necessary to change the stability of the excavator, it is necessary to reduce the pressure on the ground. Without changing the structure of the base frame, it is possible to change to a wider beam and a longer track frame so that tracks of different lengths and widths can be installed. The disadvantage is that the cross section of the track frame is weakened more, the rigidity is poor, and cracks are easily generated in the weakened cross section.

More and more hydraulic excavators use the integral running frame to overcome the above disadvantages, which are simple in structure, light in weight, high in rigidity, and low in manufacturing cost. The diameter of the support wheel is small, and in the length of the running device, each side can be installed 5 to 9 support wheels so that the upper part of the bulldozer can be evenly transmitted to the ground, easy to use in Low soil bearing capacity, improve running performance.
Four wheels and one belt
There are tracks and drive wheels, idler wheels, support wheels, paddles consisting of four wheels and one belt, directly related to the work performance and running performance of the excavator, its quality and manufacturing costs represent about a quarter of the entire machine.

• Las vías son de tipo integral y de tipo combinado, respectivamente; The track plate itself becomes a rolling track for wheels such as supporting wheels. The integral type is easy to manufacture, and the pin connecting the track plate is easy to disassemble and install, but it wears faster.
• At present, the combined track is widely used on hydraulic excavators. It has track plates, chain track joints and track pins and pin sleeves, etc. The left and right chain tracks are connected with the pin sleeve. The track pin is inserted into the pin sleeve with a specific clearance for flexible rotation. Its two ends are matched with the other two track joint holes. The locking crawler pin and the chain track knuckle hole are dynamic fit, so the whole crawler can be easily disassembled and assembled. The combination track has a slight pitch and good winding, so the excavator can travel faster. The pin and hardness are higher, wear-resistant, and have a long service life.
• The support wheel transmits the weight of the excavator to the ground, and the wheel usually bears the impact of the ground when the excavator runs on different terrain. Therefore, the load of the support wheel is more considerable. In addition, the working condition of the intermediate wheel is also poor, often in the dust, and sometimes submerged in mud and water, so good sealing is required. The supporting wheel is often cast from 35Mn or 50Mn steel, and the quenching hardness of the wheel surface is HRC48~57 to obtain good wear resistance. The support wheel is mainly supported by sliding bearings and dustproof by floating oil seals.
  The support wheel structure is fixed on the track frame by the two end shafts, as shown in the figure above. The flange on the edge of the support wheel supports the track so that it does not fall sideways when walking. In order to be able to arrange several support wheels in a limited length, a number of them are often made without external flanges, and the support wheels with or without external flanges are arranged alternately.

• Lubricating grease for the journal bearing and oil seal is added from the screw plug hole in the center of the sprocket body, which is usually filled only once during an overhaul period, which simplifies maintenance. daily excavator maintenance work.
• The guide pulley is used to correctly guide the track and prevent it from going off and crossing the track. In most hydraulic excavators, the idler also acts as a support wheel, which can increase the contact surface of the track with the ground and reduce the pressure on the ground. The idler surface is smooth, with a shoulder ring in the center to guide, and the ring surface on both sides to support the track chain. The smaller the distance between the guide wheel and the nearest support wheel, the better the guidance.

• The guide wheel is usually cast in 40, 45 or 35Mn steel, hardened, with a hardness of HB230&#;270.

tensioning device

After a while, the hydraulic excavator crawler running device will increase the pitch due to the wear of the track chain pin and cause the entire track to lengthen, resulting in the friction of the track frame , track derailment, and noisy running device, thus affecting the running performance of the excavator. Therefore, each track must be equipped with a tension device to maintain a certain degree of tension.

Piston 4 is installed in the cylinder, and oil seal 15 seals the piston and grease in the cylinder cavity. When the pressurized grease is injected from the nozzle 16, the piston pushes the piston to the right, pushing the pusher 18. The pusher pushes the front seat of the spring 6, and the front seat of the spring compresses the large and small springs 7 and 8. When the tension of the track is too big, please turn the plug 17 slowly to squeeze out the grease, not too much at a time, so that the grease will not shoot out and hurt people. When the injection pressure of the grease from the nozzle is too huge, the bulldozer can be used as an auxiliary means to facilitate the injection of the grease.

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