The structure of the transmission chain is composed of inner link and outer link. It is also composed of five small parts: inner chain plate, outer chain plate, pin shaft, sleeve and roller. The quality of the chain depends on the pin shaft and sleeve.

In the transmission device of machine tool, the commonly used transmission parts include pulley, gear, worm and turbine, gear rack, screw nut and so on. Through these transmission parts, the power source and the actuator, or the connection between the two actuators, is called transmission connection. A series of sequentially arranged transmission parts constituting a transmission connection is called a transmission chain.

The transmission chain usually includes two types of transmission mechanisms: one is the transmission mechanism with fixed transmission ratio and transmission direction, such as constant ratio gear pair, worm and turbine pair, which is called constant ratio transmission mechanism; The other is the transmission mechanism that can change the transmission ratio and transmission direction according to the processing requirements, such as change gear mechanism, sliding gear change mechanism, etc., which is called transposition mechanism.

According to the nature of the transmission connection, the transmission chain can be divided into two categories:

1. Internal connection transmission chain: according to the motion analysis, the motion (rotation and linear movement) of the actuator it is connected with belongs to an independent line motion, so the relative motion relationship between the actuator should be strict. The transmission chain with the connection property of this kind of transmission chain is called internal connection transmission chain. Therefore, the transmission mechanism with uncertain or instantaneous transmission ratio change in the internal transmission chain, such as belt transmission, chain transmission, friction transmission, etc. For example, when machining threads on a horizontal lathe, the thread transmission between the main shaft and the tool holder is an internal connection transmission chain with strict transmission ratio requirements, which can ensure and obtain the pitch required by the threads.

2. External connection transmission chain: it is the transmission chain connecting the motion source and the actuator of the machine tool. It enables the actuator to move at a predetermined speed and drive a certain power, but it does not require a strict transmission ratio relationship between the motion source and the actuator. The change of transmission ratio of external transmission chain only affects the productivity and surface roughness, and does not affect the formation of workpiece surface shape.

Chain classification

Short pitch roller chain for transmission, double pitch roller chain for transmission, sleeve chain for transmission, bent roller chain for heavy-duty transmission, toothed chain for transmission, stepless speed change chain, long pitch conveyor chain, short pitch roller conveyor chain, double pitch roller conveyor chain, double speed conveyor chain and plate chain.

Chain limit

As a common power transmission device, the chain reduces friction through the "chain" design of hyperbolic arc. It is used in places with large power and slow running speed. It has obvious advantages over belt transmission, such as tanks, pneumatic compressors, etc., but the transmission speed can not be too fast, because the flexibility of the chain is not as good as belt transmission.

classification

Stainless steel chain

The material of the parts is stainless steel, which is suitable for use in the food industry and occasions vulnerable to chemical and drug erosion. It can also be used in high and low temperature occasions.

Three chain types

All chains composed of carbon steel materials can be surface treated. The surface of parts is treated with nickel plating, zinc plating or chromium plating, which can be used in outdoor rain erosion and other occasions, but can not prevent the corrosion of concentrated chemical liquid.

Self lubricating chain

The parts are made of sintered metal soaked with lubricating oil. The chain has the characteristics of excellent wear resistance and corrosion resistance, no maintenance (maintenance free) and long service life. It is widely used in occasions with high stress, wear-resistant requirements and frequent maintenance, such as automatic production line of food industry, high-grade bicycle racing, less maintenance and high-precision transmission machinery.

Sealing ring chain

O-rings for sealing are installed between the inner and outer chain plates of the roller chain to prevent dust from entering and grease from flowing out of the hinge. The chain is strictly prelubricated. Because the chain has super strong parts and reliable lubrication, it can be used in open transmission such as motorcycle.

Rubber chain

For this kind of chain, a U-shaped attachment plate is added to the outer chain link based on a and B series chains. Sticking rubber (such as Natural Rubber NR, silicone rubber Si, etc.) on the attachment plate can increase the wear capacity, reduce noise and increase the shock resistance. For conveying.

Sharp tooth chain

It is widely used in wood industry, such as wood feeding and output, cutting, conveyor conveying, etc

Agricultural machinery chain

Suitable for field operation machinery, such as walking tractor, thresher, combine harvester, etc. This kind of chain requires low cost but can withstand impact and wear resistance. In addition, the chain should be coated with grease or can be lubricated automatically.

High strength chain

It is a special roller chain. By improving the shape of the chain plate, thickening the chain plate, fine punching the hole of the chain plate and strengthening the heat treatment of the pin shaft, it can improve the tensile strength by 15 ~ 30%, and has good impact performance and fatigue performance.

Side bending chain

The chain has large hinge clearance and chain plate clearance, so it has great flexibility and can be used for bending transmission and conveying.

Escalator chain

Used for escalator and automatic pedestrian passage. Due to the long working time, high safety requirements and stable operation of the escalator. Therefore, it is required that the step chain must reach the specified minimum ultimate tensile load, and the total length deviation and step distance deviation of the two paired chains.

Motorcycle chain

According to the definition of the purpose of the chain, there are two types of chain: roller chain and sleeve chain. From the part used on the motorcycle, it can be used inside the engine and outside the engine. Most of the chains used in the engine are sleeve chain structure, and the chains used outside the engine are transmission chains used to drive the rear wheels, mostly roller chains.

Clamping conveyor chain

It is suitable for walking wheat and rice harvesters, stationary motorized rice and wheat threshers and semi feed combine harvesters.

Hollow pin chain

For conveying, single pitch, double pitch and long pitch can be used. Accessories or cross bars can be inserted into any link of the chain without removing the chain.

Time gauge chain

Used for transmission between engine crankshaft and camshaft. Because there are strict requirements for the matching of engine piston stroke and exhaust time, it is called time gauge chain for this purpose. Roller chain and toothed chain can be used as time gauge chain. The timing chain is mainly used for the transmission of engines (diesel or gasoline engines) of automobiles, motorcycles and ships. In order to reduce the weight of the engine, the installation clearance between the chain and the engine is very small, and some even have no tensioning device. Therefore, in addition to the high precision requirements, the wear resistance requirements of the time gauge chain are also quite high.

Inspection method

Appearance inspection

1. Whether the inner / outer chain piece is deformed, cracked or corroded.

2. Check whether the pin is deformed or rotated, and whether it is corroded.

3. Whether the roller is cracked or damaged Excessive wear.

4. Check whether the joint is loose or deformed.

5. Whether there is abnormal sound or abnormal vibration during operation, and whether the chain lubrication is in good condition.

Accuracy check

1. The chain is cleaned before measurement.

2. Surround the measured chain on two sprockets, and the upper and lower sides of the measured chain shall be supported.

3. The chain before measurement shall stay for 1min under the condition of applying one-third of the minimum ultimate tensile load.

4. When measuring, apply the specified measuring load on the chain to tension the upper and lower chains The chain and sprocket shall ensure normal tooth engagement.

5. Measure the center distance between two sprockets.

Chain elongation check

Measure the tension of the whole chain to remove the tension.

2. During measurement, in order to minimize the error, measure at section 6-10 (link).

3. Measure the inner L1 and outer L2 dimensions between the rollers of the number of sections to obtain the judgment dimension L = (L1 + L2) / 2.

4. Calculate the elongation length of the chain, which is compared with the service limit value of chain elongation in the preceding paragraph.

Elongation of chain = judgment size - reference length / reference length * 100%.

Reference length = chain pitch * number of links.

Difference between chains

The standard transmission roller chain is a general transmission roller chain based on JIS and ANSI specifications. 2. Plate chain is a vertical hanging chain composed of chain plate and pin shaft. 3. Stainless steel chain is a stainless steel chain that can be used in special environments such as medicine, water and high temperature. 4. The anti rust chain is a chain with nickel plated surface. 5. The standard accessory chain is a chain with accessories attached to the standard roller chain for transmission. 6. Hollow pin shaft chain is a chain connected with hollow pin shaft. According to the requirements of customers, the pin shaft, cross bar and other accessories can be attached or removed freely. 7. Double pitch roller chain (type A) is a chain with twice the pitch of standard roller chain based on JIS and ANSI specifications. It is a low-speed transmission chain with average length and light weight, which is suitable for devices with long distance between shafts. 8. Double pitch roller chain (type C) is a chain with twice the pitch of standard roller chain based on JIS and ANSI specifications., It is mainly used for low-speed transmission and handling. There are standard diameter S-shaped rollers, large diameter R-shaped rollers 9 and double pitch accessory roller chain. It is a chain with accessories attached to the double pitch roller chain, which is mainly used for conveying. 10. Iso-b roller chain is a roller chain based on iso606-b. it is widely used in products imported from Britain, France, Germany and other places.