Elimination of Gear Backlash in CNC Machining Feed System

Elimination of Gear Backlash in CNC Machining Feed System

 

The transmission gear in the feed system of the CNC machining machine tool must eliminate the transmission gap between the meshing gears as much as possible, otherwise the motion will lag behind the command signal after each reversal of the feed system, which will affect the machining accuracy (accuracy) ). There are the following two common methods for CNC machining machine tools to eliminate the transmission gear gap.

 

1. Rigidity adjustment method

 

The rigid adjustment method is an adjustment method that cannot be automatically compensated for the tooth side clearance after adjustment. Therefore, the pitch tolerance and tooth thickness of the gear must be strictly controlled, otherwise the flexibility of the transmission will be affected. This adjustment method has a relatively simple structure and a better transmission rigidity.

 

(1) Eccentric shaft adjustment method

 

As shown in Figure 610, the gear 1 is mounted on the eccentric sleeve 2. Adjusting the eccentric sleeve 2 can change the center distance between the gear 1 and the gear 3, thereby eliminating the gap. In the numerical control processing, the control system issues instructions to make the tool perform various motions that meet the requirements, and the shape and size of the workpiece are expressed in the form of numbers and letters, and the processing required by the processing technology. It generally refers to the process of processing parts on CNC machine tools. In order to improve the degree of production automation, shorten the programming time and reduce the cost of CNC machining, a series of advanced CNC machining c17500 beryllium copper technologies have been developed and used in the aerospace industry.

 

(2) Axial gasket adjustment method

 

For a pair of meshing cylindrical gears, if their pitch circle diameter is made into a smaller taper along the gear axial direction, changing the thickness of the gasket 3 can change the axial relative position of the gear 2 and the gear 1, thereby eliminating the tooth flanks. gap. In the numerical control processing, the control system issues instructions to make the tool perform various motions that meet the requirements, and the shape and size of the workpiece are expressed in the form of numbers and letters, and the processing required by the processing technology. It generally refers to the process of processing parts on CNC machine tools. In order to improve the degree of production automation, shorten the programming time and reduce the cost of CNC machining c11000 copper, a series of advanced CNC machining technologies have been developed and used in the aerospace industry.

 

Add a shim 2 between the two thin helical gears 3 and 4, change the thickness t of the shim, and the helix of the thin gears 3 and 4 will be misaligned, so that the thin gears 3 and 4 are respectively aligned with the teeth of the wide helical gear 1. The left and right sides of the groove are tightly attached to each other, thereby eliminating the tooth side clearance.

 

2. Flexible adjustment method

 

The flexible adjustment method is an adjustment method in which the tooth flank gap can still be automatically compensated after adjustment. This method generally adopts adjusting the pressure of the pressure spring (Spring) to eliminate the tooth side clearance, and in the case of changes in the tooth thickness and circumferential section of the gear, it can also maintain a gapless meshing, but the structure of this adjustment method is relatively more. Complex, large axial size, low transmission rigidity, and poor transmission stability.

 

(1) Axial compression spring adjustment method

 

The two thin helical gears 1 and 2 are sleeved on the shaft 6 with the key 4, and the nut 5 is used to adjust the axial pressure of the pressure spring 3. The left and right tooth surfaces of the groove are tightly attached to each other, thereby eliminating the tooth side clearance. The spring force needs to be adjusted properly, too loose can not eliminate the gap, too tight will accelerate the wear of the gear (a basic type of component failure).

 

(2) Circumferential spring adjustment method

 

Two thin gears 1 and 2 with the same number of teeth mesh with another wide gear, and the gear 1 is idler on the gear 2 and can rotate relatively. CNC machining General CNC machining c17300 beryllium copper usually refers to computer digital control precision machining, CNC machining lathe, CNC machining milling machine, CNC machining boring and milling machine, etc. The feed route of finishing is basically carried out along the part contour sequence. Therefore, the focus of determining the feed route is to determine the feed route of rough machining and idle stroke. The end face of each gear is evenly equipped with four threaded lugs 3 and 8 respectively. There are four through holes on the end face of the gear 1 through which the lug 8 can pass. The spring 4 is hooked on the adjusting screw 7 and 9 lug 3 respectively. . Turning the nuts 5 and 6 can adjust the tension of the spring 4. The tension of the spring displaces the sheet gears 1 and 2 with each other, and respectively adhere to the left and right tooth surfaces of the wide gear grooves to eliminate the tooth side clearance.

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