Grinder (grinding machine) is a machine tool that uses grinding tools to grind the surface of workpieces. Most grinding machines use high-speed rotating grinding wheels for grinding, and a few use other grinding tools such as oilstone, abrasive belt and free abrasive for processing, such as honing mill, ultra precision machining machine, abrasive belt grinder, grinder and polishing machine.

With the development of CNC technology, grinding machines are widely used in the spindle of CNC machine tools such as machining centers

1、 Orifice restrictor

1。 Adjust the internal throttle to the external throttle, and increase the pressure gauge to display the pressure. It makes maintenance convenient, especially easy to clean, which is incomparable with internal throttling equipment.

2。 Throttle ratio. Throttle ratio β The theoretical value of is 1.2 to 1.5, while that based on years of experience is 1.25. During maintenance, the geometric accuracy of the main shaft, the geometric accuracy of the shaft, the coaxiality, roundness and taper are strictly controlled to ensure that β Value. According to the load capacity of the motor, the eccentricity of the main shaft and the geometric center of the axis are determined.

3。 When the oil tank is not installed, the oil column at each outlet must be consistent (observation method). If not, the method of changing the orifice diameter should change its flow. For example, the oil column of the left and right cavities is between 20 and 25 mm, and the diameter of the hole is 0.25 to 0.4 mm.

2、 Thin film feedback throttle

The stiffness of the thin film feedback throttle bearing is very large, but the machine tool often appears in the operation of grasping, pulling and pressing. The most critical factor in film feedback is the film, which is believed to be caused by plastic deformation of the film. Slow feedback. When the film did not react, the drive shaft and the tiles were wiped. Film fatigue. The fatigue deformation of long thin film is equivalent to changing the feedback parameters.

The thickness of the film and the use of some wear-resistant materials can be well obtained. Generally, the methods of rigid membrane, pre assembly and reserved groove are adopted. The specific method is to change the 1.4 mm thick film into a 4 mm thick rigid film, pad the lower cavity with 0.05 mm thick tin foil, and adjust the spindle to a position 0.5 mm higher than the ideal position. The aim is to return to the ideal center when the spindle force (grinding wheel weight and cutting force) is applied.

3、 Improve the oil supply system

In the hydrostatic bearing oil system, in addition to coarse filtration and fine filtration, other components have a protective effect on the hydrostatic bearing. On the basis of the original system, the oil supply system is improved.

1。 The outlet pressure relay and pressure gauge are connected to the pressure gauge (initially in front of the battery), so that the operator can see the pressure of the cavity and the inlet pressure. When the pressure difference is greater than a certain value, the machine will stop immediately to avoid bearing death. For example, the inlet pressure is 2MPa, and the outlet pressure is 1.2 ~ 1.6 MPa. If it is lower than 1.2 MPa, it will stop.

2。 Add digital detection equipment

Between the static bearing and the main shaft of the shaft, between 0.04 and 0.05 mm, the oil has a certain resistance, and the change of the resistance value can be detected and the size of the interval can be known. The main shaft is one pole and the shaft is the other pole. Measure the change of resistance. After signal processing of the photoelectric alarm and control system amplifier, the start and stop time of the spindle motor is controlled to avoid friction between the shaft and the bearing.