The first point is to improve the machining quality of tooth blanks
In the process of gear machining, the machining quality of the tooth blank has a fundamental impact on its accuracy, because in fact, the basis of the subsequent machining of the gear is directly related to the installation and positioning accuracy of the gear machining. For example, in the process of gear hobbing, if the installation gap of the gear blank is relatively large, it is easy to cause the eccentricity of the gear blank processing. This will not only cause the ring gear to have an excessive runout deviation of the ring diameter, but also directly affect the subsequent processing of the gear, and in severe cases will cause the processing of precision gears to fail.
In addition, the runout accuracy of the ring gear blank will also have a negative impact on the shaving process. This is because the positioning surface during shaving is the end face of the gear, and the bevel teeth are usually formed at the maximum circular runout position of the gear blank. of. Therefore, in the process of gear processing, the processing quality of the gear blank should be strictly controlled. The specific requirements are: in the process of processing hole-type gears, the gear hole accuracy should be controlled at the H6 level, and the outer circle of the gear blank should not be larger than 80 in diameter. The runout of the end face must be controlled within 0.017, and if it is greater than 80, it should be controlled within 0.022 1; when machining shaft gear blanks, the positioning of the outer circle dimensional accuracy should be carried out according to the H5 level, and the outer circle runout should be controlled within 0.015 .
The second point is to improve the accuracy of the machine tool itself
The machining of precision gears is inseparable from the machine tool, so the performance and accuracy of the machine tool will also directly affect the machining accuracy of the gears. According to relevant statistics, most of the reasons for the decline in the machining accuracy of gears are the problems of the machine tool itself. Therefore, in order to improve the machining accuracy of gears, it is necessary to start from improving the accuracy and work performance of the machine tool. The specific measures are as follows:
1. Before processing, carefully check the details of machine tool parts and other aspects, scientifically and carefully adjust the cutting amount, material installation, etc., especially pay attention to the selection of tools, the setting of geometric parameters, and the lubrication and cooling of the machine.
2. Before the machining of precision gears, the rigidity of the tool should be improved, and the equipment should be maintained in time; once a problem occurs during the machining process, the maintenance personnel should be notified, and strive to solve the problem as soon as possible to prevent the accuracy of gear machining from being affected.
The third point is to reduce the error between precision gears and tooling clamping
While improving the accuracy of the machine tool itself, we should also reduce the error between the gear and the tooling, which is also an important measure to improve the machining accuracy of the gear. In addition, improving the processing technology and improving the accuracy of the central axis of the fixture and the center of the mold can also achieve the purpose of improving the machining accuracy of the gears.
The last point is to improve the processing technology of precision gears
In addition to the infrastructure such as tooth blanks, machine tools and fixtures, the machining process is also an important factor affecting the machining accuracy of gears. In order to improve the machining accuracy, the machining process should be continuously improved. The specific measures are as follows:
1. Ensure that the worktable and the central axis of the fixture can be completely coincident. Usually, we will install the spigot on the bottom of the fixture. Although the gap between the spigot and the worktable is small, there will still be errors. Therefore, we should try to avoid gaps during installation.
2. Before installing the tool, it should be fully checked to ensure that the end face and inner hole of the tool are clean, and the blade should be gently pushed into the handle. It is strictly forbidden to use heavy objects to hammer the handle.
3. Improve the precision of hobbing. Gear hobbing is a common treatment method when we process gears. In order to improve the accuracy of gear hobbing, we must use a sophisticated hob to operate on a precision gear hobbing machine. In addition, it should also ensure that the center of rotation of the machine tool and the center of the gear perfectly coincide to effectively reduce the radial error; improve the accuracy of the rotation of the worm gear pair of the worktable; place the tool holder and the machine tool vertically in a predetermined area, and scientifically adjust it and each part Offset of the axis, control the amount of grinding, and it is strictly forbidden to generate more allowance.
4. Improve the heat treatment capacity of the gear itself. Generally, in the process of heat treatment, the accuracy, hardness and service life of gears will be affected to a certain extent, and after heat treatment, tooth grinding treatment is required, which will also affect the accuracy of gears. Therefore, strict control All links and details in the processing of precision gears are the most powerful measures to ensure accuracy.