A Method For Measuring Pitch Deviation Of Spiral Bevel Gears

The spiral bevel gear has the advantages of smoothing transmission,compact structure,low transmission noise and strong carrying capacity.As the main device of transmission power,the spiral bevel gear is widely used in automobile,high-speed railways,aerospace,ships and other mechanical equipment.The manufacturing level of mechanical equipment is directly influenced by the quality,performance and service life of spiral bevel gears.As an important indicator for evaluating gear transmission performance,tooth pitch deviation has a direct effect on the transmission accuracy and stability of gears.Therefore,it is extremely important to detect the pitch deviation of the spiral bevel gear.It is difficult to detect the spiral bevel gear with special shape through the currently widely used measuring equipment which is proposed for cylindrical gears and spur gears.So the improvement and development of spiral bevel gear manufacturing level in China is restricted.At present,most of the measurement methods for the spiral bevel gear are contact measurement.The method of contact measurement has some disadvantage,such as need to set up the measurement path in advance and position compensation for probe radius,in addition the tooth surface can be scratched by the probe during the measurement process.In this paper,a non-contact measurement method for the pitch deviation of spiral bevel gear based on the laser displacement sensor is proposed.The main contents of this paper are as follows:Firstly,a non-contact measurement system for the pitch deviation of the spiral bevel gear is constructed,and the laser displacement sensor was used as the main measurement tool.The main task is to complete the overall structural design of the measurement system.In order to realize high-precision measurement for the middle tooth width profile of the spiral bevel gear,we need to cooperate with the laser displacement sensor and rotary platform.And the hardware design and type selection of the measurement system are expounded in detail.Secondly,the measurement principle is introduced for the non-contact measurement system proposed in this paper.The reading of the laser displacement sensor and the reading of the circular grating ruler are stored as a set of coordinate data in the data file during the measurement.The PC data processing system first removes the individual distortion measurement data caused by a variety of factors such as the external environment and the measurement system.The improved three B-spline method is used to process the measured data and fit the tooth profile curve of.The intersection point Pi of the actual tooth profile and the indexing circle is obtained by combining the fitting equation of the tooth profile and the equation of the indexing circle,and the actual tooth pitch can be further determined.Thus the tooth pitch deviation data is obtained by comparing with the theoretical tooth pitch.At last,the main error factors which affecting the accuracy of the measuring system are analyzed,the main error includes environmental error,random error and measurement system error.And corresponding compensation measures are proposed for different error factors.The measurement system proposed in the paper is used to carry out the measurement experiment.The feasibility and correctness of the measurement method proposed in this paper are verified by comparing with the measurement results of gear measuring center.