Views: 0 Author: WTG Publish Time: 2021-10-29 Origin: WTG
The standard tooth profile equation of the cycloid needle is meshed with the standard needle wheel, and the cycloid needle tooth profile conjugate with the needle wheel and without meshing clearance is called the standard tooth profile. Select the geometric center of the cycloid pin gear as the origin, and the axis passing through the origin and coincident with the symmetry axis of the cycloid gear groove as the axis. In order to compensate manufacturing error, facilitate assembly and disassembly and ensure lubrication, there must be meshing clearance between cycloid gear and needle gear in practical application of cycloid needle gear planetary transmission. Therefore, the actual cycloid gear can not adopt the standard tooth profile, but must be modified.
When machining cycloidal gear with displacement modification method, the eccentricity, grinding gear shape radius and transmission ratio are the same as those of machining standard gear shape. The difference is that when the grinding wheel is moved a distance to the center of the worktable, a negative value should be used instead of people. Therefore, the ground teeth are smaller than the standard tooth profile and mesh with the standard needle wheel, which will naturally produce meshing clearance. When the grinding wheel moves away from the center of the worktable, it is called positive displacement. When machining cycloid gear with equidistant modification method, the adjustment and parameter selection of machine tool motion are basically the same as that of machining standard tooth profile. The difference is that the arc radius of grinding wheel is increased from standard to RP + Trp. Although the short amplitude coefficient of grinding cycloid gear profile has not changed, it is two equidistant curves with the same short amplitude epicycloid equidistant value as the standard tooth profile. In this way, the grinding teeth are smaller than the teeth with standard tooth profile, and the meshing clearance will be generated when meshing with the standard needle wheel.
When the cycloid pin gear reducer processes the cycloid gear, the adjustment of the machine tool is completely the same as that of the standard tooth profile. Only after the standard tooth profile is grinded for the first time, disconnect the connection between the gear dividing mechanism and the eccentric mechanism, and then move the gear of the gear dividing mechanism to make the cycloid wheel workpiece rotate a small angle, so as to change the initial position of the cycloid wheel during grinding, and carry out the second grinding according to the original method, which will make the thickness of the whole tooth of the cycloid wheel slightly thinner and the tooth groove slightly increased. In theory, the cycloid wheel grinded by corner modification is installed in the standard needle wheel, which still belongs to conjugate tooth profile meshing. At this time, the number of stressed teeth is large, the transmission is stable and the side clearance is uniform, but there will be no clearance contact between the tooth top and tooth root, so it can not compensate the manufacturing error of the radial dimension chain and meet the lubrication requirements, so it can not be used alone. In this way, other methods must be added to modify the tooth top and tooth root to ensure an appropriate amount of radial clearance. For the needle wheel transmission of cycloid needle wheel reducer with large transmission ratio, due to the small relative tooth pitch, if the cycloid tooth shape is to be ensured not to produce top cutting, the allowable needle tooth radius is small, so the needle tooth pin without needle tooth sleeve can only be used for transmission. At this time, there is sliding friction between cycloid wheel and needle tooth, resulting in increased temperature rise and greatly reduced transmission efficiency. In order to improve the transmission performance, one of the effective measures is to increase the needle tooth radius and install the needle tooth sleeve on the tooth needle, so as to change the rolling friction between the cycloid wheel and the needle tooth. When using cycloidal pinwheel reducer, pay attention to selecting standard pinwheel.