Research On The Movement And Controlling Of The Spiral Bevel Gear With Spherical Involute Profil Machining

Bevel gear transmission is one of important forms of gear transmissions, and it is used for transmission between the two intersection rotating axes. In automobiles, tractors, machine tools and other mechanical products, as well as many power transmission devices, it has been increasingly widely used, and the spiral bevel gear has the characters below: the coincidence degree is big, fit for heavy-duty transmission, well transmission stability; therefore, the spiral bevel gear has an important position among various types of bevel gears production occupies. Because a spiral bevel gear is a partial conjugate contact gear which tooth surface has a very complicated structure, and its manufacture is a little more complicated than cylindrical gear, its productivity, accuracy, quality have been certain restrictions. Therefore, the spiral bevel gear manufacturing technology is very important for the improvement of spiral bevel gear transmission quality.The article analyzed and explained a new spiral bevel gear processing methods - the generating-line method. From the spherical involute generation principle, and related to the current spiral bevel gear processing methods, the article proposed that if the plane Q absolutely rolling relatively to the base cone, and keep the velocity ratio thatωω= sinδb, then the cutting edge of the knife in the plane Q will form the tooth surface of a spiral bevel gear. In the article, the contents below are involved:1. Introduced the common methods and the development condition for manufacturing a spiral bevel gear at home and abroad, especially focused on the manufacture method and the production condition of the Gleason in United States2. Demonstrated the spherical involute formation theory, and from this suggested that if the base cone absolutely rolls relatively to its tangent plane, then the arc line in the tangent is the generation line for the tooth surface of a spiral bevel gear with spherical involute profile. If the generation line is made to the cutting edge, during the course that the base cone rolling relatively to its tangent plane, the arc cutting edge will form the tooth surface of a spiral bevel gear with accurate spherical involute profile.3. Analyzed the desirable movements for such a method, and the achievement of these movements. Proposed and established the method that the work piece continuously rolls, the knife plate continuously rolls envelope and conjugate manufacturing method, including the cutting edge of the knife and the knife plate designing, the movements of the machine tool etc. Computed the moving trace of the knife during the cutting process and cutter withdraw process. Proposed the number of the cutters and the movement relation under which the cutter does not interfere with the tooth of the gear. The research results showed that with this method, the movement and structure of the machine tool is simple, the cutter is simple, and can achieve that the rough and finis machining of the convex and concave surfaces can be finished if the work piece is only fixed one time, and the big and small gear, the levorotation and dextral gears can be manufactured by the same machining tool and cutter, and the contact area is easily to controlled.4. Designs the mechanical structure, the electric of the cutting device, does the experiments for cutting and transmission;Through many cutting and transmission experiments, the following conclusions were obtained:(1) According to the principle that the tooth surface of a spiral bevel gear can be generated by an arc line in a plane rotating around the base cone, if the generating arc line were made to the cutting edge, then it will form the tooth surface of a spiral bevel gear with a no theoretical error spherical involute profile. The principle is simple, and the cutting way is convenient. Because the tooth surface is spherical involute profile, and it is completely conjugated in theory, so it will not be necessary that according to the small gear to manufacturing the bigger gear. Because the profile is known and conjugated, even the contacting area adjusting is also very convenient, and the cutting way provides an advantage for an active controlling for the contacting area. Because the tooth surface of the gear is cutting one time, the efficiency of the finish machining is very high.(2) The cutting edge can bring velocity in two directions, one is the cone generating line direction, and the other one is the radial direction of the work piece. The cutting speed is proportional to the angular velocity of the work piece and the radius of the cutting plate, and changes corresponding to the phase of the plane (Q). When the cutting edge is in the middle of the gear, the cutting velocity is the biggest.(3) The three-axis linkage movement and achievement method proposed in this paper, can complete cutting gear effectively, and its way is very simple, and the movement and the structure of the machining tool are both simple.(4) Using the digital technology, and keeping the relationship:ωω1 = sinδb, it is not necessary to be limited by that if the number of the teeth is an integer as the transmission parts, so it can achieve any pressure angle.5) Installing several kinds of the knives in the same knife plate, then it is not necessary to change the knife plate or the cutting edge can complete the rough machining, finish machining the convex face, finish machining concave face with the work piece being fixed one time. The bigger and smaller, the right lateral and the laevorotation gears can be machined by one machining tool and the same cutting plate. Under the condition that the cutting plate is not continuously rolls, twelve knives can be installed in a cutting plate, and will not interfere.(6) through the analysis of the gear, the cutting plate, the movement of the cutting edge, the cutting process, only if the cutting tool back movement corresponds to the velocity of the cutting plate and the number of the knives, it will achieve a continuously machining. That is, a knife moves out from the cutting zone, and then the next cutting tool moves into the cutting process. It is suggested that a cutting plate installs 6 knives, and the knife will not interfere to the work piece.7) The principle and method provide a new way for the spiral bevel gear machining. It can decrease the equipment value and the usage cost under the premises that assuring a high accuracy and its operation is also convenient.