Gear and rack manufacturers have compiled control methods for precision machining of gears and racks for everyone. Interested friends, let's take a look together!

The equipment and processing methods used in this process are the same as those in the previous sequence, but the difference lies in the control of the machining accuracy of the gear rack. First, clamp the workpiece with its bottom facing the machine spindle, place an equal height shim underneath, and gently clamp it after alignment. Machine the bottom surface of the gear rack to a machining allowance of 0.3mm, then flip the workpiece 180 ° and place it on the equal height shim to process the tooth profile. First, machine the tooth top surface to the size shown in the drawing. Due to the high requirements for tooth thickness and pitch accuracy, a measuring rod is used to control the accuracy of tooth profile during precision machining.

When selecting the diameter of the measuring rod, the contact point between the outer circle of the measuring rod and the tooth profile should fall on the dividing line and its nearby position. Generally, the selection is based on the diameter of the measuring rod D=(1.68-1.72) m, where m is the end face modulus (mm). After calculation, rounding is adopted φ Measure with a measuring rod of (80 ± 0.01) mm. The specific control method is to draw the distance h between the top point of the standard measuring rod and the tooth top according to the dimensions required in the drawing.

During the machining process, first machine one side of the tooth slope to meet the requirements of the drawing, then place the measuring rod in a tooth valley, and use a dial gauge to measure the actual distance h ′ between the measuring rod and the tooth top. The difference between h ′ and h is: Δ h. So the machining allowance A of the cutterhead along the length direction of the rack can be calculated according to formula A=2 Δ Htan25 ° for calculation.

After the gear rack manufacturer completes the precision machining of one tooth, the machine tool slide moves 152.4mm along the length direction of the gear rack to process two teeth, sequentially processing each tooth and its length dimension. The tooth surface is processed according to three rounds of cutting. Next, the R15 ball cutter is used to clean the root of the tooth. After the tooth profile machining is completed, the workpiece is flipped over to remove the machining allowance for thickness and width, and then transferred to the next sequence for assembly.

It is difficult to control the deformation when directly machining the tooth shape from the forging blank, which requires a reasonable process sequence and clamping method for machining the workpiece rack; The requirements for tooth thickness tolerance and tooth pitch error of the rack are very small, and the cumulative error of tooth pitch within the full length range is only 0.4mm. If forming milling cutters or hobbing cutters are used for processing, as the processing continues, the tool may wear out, which cannot maintain tooth pitch accuracy and will lead to an increasing cumulative error of tooth pitch, which cannot meet the requirements of the rack.

The above is the relevant content about the control methods for precision machining of gears and racks. If you need gears and racks, please contact us!