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HomeIndustry InformationWhat's worm gear motor?

What's worm gear motor?

According to the structural characteristics of precision reducers and the load characteristics of gears, hard-toothed gears should be widely used. There are many ways to heat treat hard gears. Such as surface hardening, overall hardening, carburizing hardening, nitriding, etc., should be selected according to the characteristics of the gear reducer.

1. Surface hardening

Common surface hardening methods include high frequency hardening (for small size gears) and flame hardening (for large size gears). The surface-hardened hardened layer works best when it includes the bottom of the tooth root. Tooth surface hardness can reach 45-55HRC.

2. Nitriding

The use of nitriding can ensure that the gear can achieve high tooth surface hardness and wear resistance under the conditions of minimal deformation. The best finishing is no longer performed after heat treatment, which improves the bearing capacity.

3. Carburizing and quenching

Carburizing and hardening gears have a relatively large load-bearing capacity, but the finishing process (grinding) must be used to eliminate heat treatment deformation to ensure accuracy.

Carburizing and quenching gears commonly use a carbon fraction of 0.2% to 0.3% before alloying. The tooth surface hardness is usually in the range of 58-62HRC. If it is lower than 57HRC, the hardness of the hard surface is significantly reduced and high Brittleness increased at 62HR. The hardness of carburizing and quenching gears gradually decreases from the gear surface to the deep layer, and the effective carburizing depth is specified as the depth from the surface to the hardness of 5.25HRC.

The effect of carburizing and quenching on the bending fatigue strength of gears is not only to increase the hardness of the core, but also to the residual compressive stress on the surface. It can reduce the stress in the maximum compressive stress region, so the tooth root cannot be ground when grinding the teeth.

Gear transmission lubricant knowledge


Gear transmission lubricant knowledge

Gear transmission lubricant is referred to as gear oil, which is mainly used to lubricate various mechanical gear transmissions. Gear oil, like lubricating oil for internal combustion engines, is also composed of mineral oil (or synthetic) base oil and corresponding additives. Gear oil can be divided into two categories: vehicle gear oil and industrial gear oil.

Gear Oil Introduction

Vehicle gear oil is mainly used in automotive, engineering machinery transmissions, steering gears, gearboxes of front and rear drive axles, universal joint needle roller bearings, and other components. It can also be used for gears of tanks and ships with corresponding loads and working conditions Parts. Industrial gear oil is mainly used in open, semi-open, closed and worm gear transmissions under various load conditions.

First, the working conditions of gear oil and its role:

Gears in various mechanical transmission mechanisms can be divided into parallel shaft transmission, intersecting shaft transmission and staggered shaft transmission according to the different positional relationships of their axes. Each type of transmission has different transmission methods according to the shape of the gears and teeth, such as spur gears, helical gears, and herringbone gears that are driven by parallel shafts. Toothed bevel gears, spiral bevel gears; interleaved shaft drives are hyperbolic gears, worm gears, and helical drives.

1.Gear transmission characteristics and gear oil working conditions

(l) High gear transmission efficiency, general cylindrical gear transmission efficiency can reach 98%, compared with the bearing, the gear's equivalent curve radius is small, and the oil wedge condition is poor.

(2) The gear transmission teeth are in line contact with the teeth, so the contact area is small and the unit contact pressure is high. The unit contact pressure of general automotive gear can reach 2000-3000MPa, while the hyperbolic gear is higher, which can reach 3000-4000MPa.

(3) Gear transmission has not only wired contact, but also sliding contact, especially hyperbolic gears, which have relatively high sliding speeds between the gear teeth, which can generally reach about 8m / o. Under high-speed and large-load conditions, the oil film will become thin or even partially ruptured, resulting in increased friction and wear, and even scratches and occlusions.

(4) The working temperature of gear oil is generally lower than that of internal combustion engine oil, which changes to a large extent with the change of ambient temperature. The temperature of vehicle gear oil is generally not higher than 100'C. Hyundai cars use hyperbolic gears. Because of the large axis offset, the relative sliding speed of the gear wheel surface is high when the vehicle speed is high, and the oil temperature reaches 160′C to 180’C.

2.The role of gear oil in gear transmission

(1) Reduce the wear of gears and other moving parts and extend the life of gears.

(2) Reduce friction and reduce power loss.

(3) Disperse heat and play a certain cooling role.

(4) Prevent corrosion and rust.

(5) Reduce working noise, vibration and impact between gears.

(6) Wash the dirt, especially the dirt between the tooth surfaces, to reduce wear.

Second, the nature of gear oil:

Due to the different purposes of the gear oil, the conditions of use are also very different, and its use performance has the following requirements:

1.Good oiliness and extreme pressure abrasion resistance

Oiliness means that the gear oil can effectively adsorb the lubricating oil film between the moving lubrication surfaces and has the property of reducing friction. Abrasion resistance refers to the ability of the oil to maintain an oil film between moving parts, which can effectively prevent direct contact between metals. Adding active substances with polar molecules to the gear oil can improve its oiliness. The polarity of these oiliness agents The oxide on the end and the metal surface will adsorb, forming a solid oily film. The polar end of the oily agent may also form a metal soap-type lubrication film with the oxide on the metal surface, enhancing the lubrication of the gear oil and preventing the tooth surface. Direct contact reduces friction and therefore wear. Some gear transmissions often work under severe extreme pressure lubrication conditions, and the pressure, sliding speed and local temperature they bear are very high, which requires extreme pressure additives to be added to the gear oil. Extreme pressure additives are generally chemically active parathion-type or parathion-type chlorozinc-type oil-soluble compounds. These additives form iron chloride, sulfur, and phosphorus compounds or compounds with the tooth surface metal under high temperature and extreme pressure conditions, forming a kind of High melting point inorganic film, this extreme pressure film has the performance of extreme pressure resistance, and also has the effect of resisting the impact load. It can effectively prevent tooth surface abrasion and occlusion under high load conditions.

2.Good viscosity-temperature characteristics

The viscosity of various lubricating oils decreases with increasing temperature, and the smaller the reduction ratio, the better the viscosity-temperature performance. In particular, the operating temperature of gear oils for automobiles and construction machinery varies widely. Therefore, it is desirable that the viscosity of gear oils change with temperature as small as possible. If the viscosity and temperature characteristics of the gear oil are not good, the viscosity is too high at startup, and it is not easy to start, and the viscosity is too small when the temperature reaches the high limit. The viscosity of gear oil is also one of the important performance properties. The viscosity has a great influence on the formation of oil film. Generally speaking, high-viscosity gear oil can effectively prevent gear and bearing damage, reduce mechanical operation noise and reduce oil leakage; low-viscosity oil has advantages in improving mechanical operation efficiency, strengthening cooling and cleaning functions, and oil transmission. In order to reduce fuel consumption, engine oil and gear oil have been reduced in foreign countries. The advantages of low-viscosity gear oil are that the gear teeth have small stirring resistance, and have good low-temperature fluidity, which can ensure lubrication under low-temperature conditions. In recent years, some low-viscosity gear oils have also been produced in China. In order to improve their lubricating properties, some multi-effect additives have been added, which is very beneficial for reducing power loss. Of course, when the body is used, the sealing of the gear box body must be strengthened to prevent leakage of gear oil.

3.Good low temperature fluidity

Vehicle gear oil is required to maintain the necessary fluidity at low temperatures. If the gear oil has wax precipitation at low temperatures and the viscosity rises sharply, effective lubrication cannot be ensured. The low-temperature starting torque increases and fuel consumption increases.

Tests have shown that the low-temperature apparent viscosity of gear oils has an important effect on the reliability of lubrication at the start of a vehicle. After the vehicle starts, the rear axle (front axle) gear oil is splashed onto the upper part of the axle housing and flows into the front bevel gear front bearing. If this time is too long, the bearing may be burned due to lack of oil. Therefore, it is required that the low temperature apparent viscosity of the vehicle gear oil is not more than 1.5X100000 mPa.s. The temperature of the apparent viscosity of the vehicle gear oil specification is 1.5X100000mpa.s, which determines the minimum temperature applicable to the gear oil, which is one of the important basis for selecting gear oil. In order to make gear oil suitable for use under low temperature conditions in winter, a pour point depressant should be added to the gear oil to improve its low temperature fluidity.

4.Good thermal oxidation stability

Gear oil under severe working conditions, under the action of air, moisture and metal catalysis, the oxidation speed is accelerated, the viscosity is increased, insoluble and corrosive substances are produced, as well as colloids and asphaltenes, which have deteriorated properties and are easy to emulsify and foam Shorten oil change intervals. In order to delay the oxidation of gear oil, phenol-type, amine-type or vulcanized antioxidant additives are generally added to the oil.

5.Good rust and corrosion resistance

Anti-rust property means that the gear oil protects the gear from corrosion, thereby ensuring the gear's performance and extending its service life. During the operation of the gear, the moisture in the air condenses into water in the gear box, so the gear oil is required to have good rust resistance. In order to improve the anti-rust property of gear oil, anti-rust additives such as sulfonate or fatty acid salt are generally added. Gear oils with extreme-pressure additives contain sulfur compounds in the extreme-pressure additives, and sulfur easily corrodes copper. Therefore, anti-corrosion additives should be added to gear oils, which can form a protective film on the metal surface to prevent corrosion Substances attack metals.

6. Good foam resistance

Gear oil is required to have good anti-foaming performance, in order to ensure the production of gears during the vigorous stirring process under operating conditions.