Differential ring gear vacuum heat treatment

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The automobile differential can make the left and right (or front and rear) drive wheels rotate at different speeds. It is mainly composed of left and right side shaft gears, two planetary gears and a gear carrier. The function is to make the left and right wheels roll at different speeds when the car is turning or driving on uneven roads, that is, to ensure that the driving wheels on both sides perform pure rolling motion. The differential is installed to adjust the speed difference between the left and right wheels. In four-wheel drive, in order to drive four wheels, all the wheels must be connected. If the four wheels are mechanically connected, the car cannot rotate at the same speed when driving in a curve. In order to allow the car to drive in a curve The rotation speed is basically the same. At this time, a middle differential needs to be added to adjust the speed difference between the front and rear wheels.

Ordinary differential is composed of planetary gear, planetary carrier (differential case), side gear and other parts. The power of the engine enters the differential through the transmission shaft, directly drives the planetary wheel carrier, and then the planetary wheel drives the left and right half shafts to drive the left and right wheels respectively. The design requirements of the differential meet: (speed of left axle shaft) + (speed of right axle shaft) = 2 (speed of planetary wheel carrier). When the car is going straight, the rotational speeds of the left and right wheels and the planetary carrier are equal and in a balanced state, but when the car turns, the balanced state of the three is destroyed, resulting in a decrease in the rotational speed of the inner wheel and an increase in the rotational speed of the outer wheel. Differentials on modern cars are usually divided into two categories: gear differentials and slip differentials according to their working characteristics.

Starting from several main factors affecting the deformation of the gear vacuum heat treatment, analyze the causes; and through a series of tests to analyze the specific factors affecting the deformation of the differential ring gear vacuum heat treatment, take corresponding measures to reduce the heat treatment deformation, so as to improve the its precision.

Influencing factors of gear vacuum heat treatment deformation

The deformation of vacuum heat treatment directly affects the accuracy, strength, noise and life of the gear. Even if the gear grinding process is added after the vacuum heat treatment, the deformation will still reduce the accuracy level of the gear. There are many factors affecting the deformation of vacuum heat treatment, the main ones are the following aspects

1 Influence of gear material on gear deformation

The hardenability curve of the same grade of steel smelted in different heats will vary within a certain range. Due to the different hardenability of raw materials, the hardenability bandwidth is different, and the structure after vacuum carburizing and quenching will be different, and the deformation will be different.

2 Influence of preparatory heat treatment on gear deformation

The uniformity and stability of the gear blank preparatory heat treatment structure have a great influence on the final heat treatment deformation of the gear, because the original structure of each part of the gear is different, the specific heat is different, and the dimensional changes during the heat treatment process are also different.

3 Influence of vacuum carburizing process on gear deformation

The uniformity of the carburized layer, the uniformity of the temperature, and the uniformity of the temperature of the cooling medium will affect the gear deformation. With the increase of carburizing temperature, the shape deformation of the workpiece intensifies, and the quenching temperature increases. The workpiece deformation will also be severe.

4 The influence of clamping methods and fixtures

Appropriate clamping methods and fixtures can make the workpiece evenly heated and cooled, and the carburized layer of each part of the workpiece is uniform, so as to reduce uneven thermal stress, uneven tissue stress, and reduce deformation. The key to the deformation of the gear during the heat treatment process is to master its deformation law.

Equipment selection: The RVN series vacuum heat treatment furnace produced by SIMUWU is a high-quality product for the vacuum heat treatment of tooling and molds. Good temperature control accuracy and temperature control uniformity ensure the effective progress of the vacuum heat treatment process. SIMUWU specializes in the manufacture of vacuum furnaces, has more than ten years of relevant experience, and has a good reputation in the field of vacuum furnace manufacturing. The product line includes vacuum air quenching furnace, vacuum oil quenching furnace, vacuum brazing furnace, etc., which are widely sold in developed and developing countries.