In order to ensure product quality and improve inspection efficiency, a large number of special measuring tools are used during the entire process of bearing inspection, of which special standard parts are the most used.

  1. Commonly used standard parts

  Currently, the standard parts used by each bearing factory are from different sources. The qualified factories are manufactured by the factory's machine repair (tool) workshop, and only some standard parts such as groove diameter standard parts are selected from the production parts. Except for outsourcing or self-made parts of factories that do not meet the conditions, almost all of them are selected from the production parts. Generally speaking, the precision of the specially manufactured standard parts is high, and the precision of the standard parts selected from the production parts is lower, but as long as the selection is reasonable and correct, the quality requirements of the bearing parts can also be guaranteed. The selection of measuring tools is the task of measurement. They regularly and regularly verify the performance of measuring tools. As users, they must strictly abide by the system of measuring tools and instruments.

  Except for the reference parts in the measurement room, the standard parts used by our company in the production workshop are basically selected from the production parts, and can be used as standard parts after being qualified by the measurement room according to the technical conditions. During the verification, the measurement room marked the manufacturing size and serial number of the standard part on the standard part. The actual size of the standard part is based on the standard part verification card issued. In addition, the outer diameter or end face of the standard part is also marked with a "|" mark, which indicates the position of the measuring point of the standard part. Therefore, when adjusting the watch, the tip (or the fulcrum corresponding to the tip) must be at "|" on the mark.

  1) Width standard parts

  Width standard parts are used to inspect the width of the inner ring and outer ring of the bearing. The width standard parts are matched with G903 series measuring instruments and meters to measure the width of the ferrule. No bumps, burrs, etc. are allowed on the working surface of standard parts. There are bruises and burrs on the work surface, which must be re-verified to avoid measurement errors.

  2) Inner diameter and outer diameter standard parts

  Inner diameter and outer diameter standard parts are used to inspect the inner diameter and outer diameter of the bearing, respectively. The inner diameter and outer diameter of the bearing are the main dimensions of the bearing and are one of the important items that determine the quality of the bearing. Therefore, the verification of inner diameter and outer diameter standard parts must be accurate.

  Inner diameter standard parts cooperate with D923 series inner diameter measuring instruments and meters, which can measure inner diameter size, inner diameter variation in a single radial plane and runout amount of inner ring reference end facing inner diameter. The outer diameter standard parts are matched with D913 series outer diameter measuring instruments and meters, which can measure the outer diameter size, the variation of the outer diameter in a single radial plane, and the variation of the inclination of the outer diameter surface generatrix to the reference end surface.

  3) Ditch diameter standard parts

The inner groove diameter and outer groove diameter standard parts are used to inspect the diameter of the inner and outer grooves of the bearing, respectively. The parts selected from the product have the groove diameter, groove curvature, groove symmetry, and the variation of the groove diameter in a single radial plane. Items such as quantity must be qualified. The channel standard parts are divided into internal and external channel standard parts.

  Internal channel standard parts are matched with D022 series internal channel measuring instruments and meters, which can be used to measure the diameter of the inner ring channel and the variation of the inner channel diameter in a single radial plane. The outer channel standard parts are matched with D012 series outer channel measuring instruments and meters, which can be used to measure the diameter of the outer ring channel and the variation of the inner and outer channel diameters in a single radial plane.

  4) Clearance and vibration standard parts

  The clearance and vibration standard parts are used to test the clearance and vibration of the bearing respectively, which are selected from the products. The clearance standard parts are matched with X092 series radial clearance measuring instruments and instruments to measure the radial clearance of the bearing. The vibration standard part is matched with the S0910 or BVT-1 vibration measuring instrument to measure the vibration acceleration (or speed) level of the bearing.



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  Pay attention to the problems when using standard parts:

  A. Standard parts have certain technical requirements, such as nominal size and actual deviation, geometric accuracy, position accuracy, hardness, appearance (including surface roughness and surface defects), so they must be handled with care to prevent bumps. After use, clean and wipe it in time, and put it in the designated position.

B. In actual production, we often encounter errors between standard parts, that is, after checking the contents of the two standard part verification cards, the measured results of the parts are inconsistent, which means that the actual deviation of the standard parts does not match the marking The content, the standard parts must be further checked. Generally, the error of the disagreement between the two standard parts is 0.001mm. If it exceeds the range, it should be stopped and re-verified.

C. The standard parts and ferrules have the physical phenomenon of thermal expansion and contraction. The measured ferrule is affected by the cutting temperature during processing, and its expansion coefficient is completely different from the size of the standard part at room temperature, due to the temperature difference between the two (Referred to as temperature difference) causes measurement errors. Especially for the internal and external grinding of the bearing parts, the temperature difference is particularly obvious. This requires the bearing parts and the standard parts to be at the same or close temperature (usually called "combined temperature"), and then check the table. The production of precision bearing parts should pay more attention to the temperature difference.

"One way to heat up is to put the standard parts on the workbench between the bearing parts, and park for a period of time (approximately 15 minutes) for inspection. Another method is to put the standard parts on the machine tool of the tested part. The "combined temperature" in the cutting fluid, such as grinding the outer diameter of the part, the cutting speed is fast, and the machine tool needs to be adjusted in time after measurement. This requires frequent calibration of the measuring instrument with standard parts. Since the standard parts have been placed in the cutting fluid of the machine tool, However, the temperature of the cutting fluid rises due to the cutting heat, and the temperature of the standard parts also rises accordingly. In this case, the use of standard parts to check the table will reduce the error of the table and ensure the machining accuracy of the measured product.

  2. Common gauges

  1) Groove R curvature gauge

   Groove R curvature gauge (commonly known as scratch ball), the R surfaces of the steel balls at both ends are the workpiece surfaces for checking the curvature of the ferrule groove, respectively. When the groove curvature is checked, the steel ball of the gauge is slightly stained with red lead.

  The maximum limit and minimum limit of plug gauge diameter, namely large range and small range. Coat on the channel of the inspected ferrule, then use a large fan to scrape the ferrule channel, observe the red residue on the surface of the channel under the light, to check the radius of curvature of the groove and the roundness of the arc.

The   curvature gauge was deliberately made to be longer for the large scale and shorter for the small scale, and the number and size were marked on the gauge.

  2) Plug gauge

  The shape of the plug gauge is used to check the hole diameter. The cylindrical surface at both ends of the plug gauge is the working surface for checking the hole diameter, and the middle part is the handle. The cylindrical working surface is divided into "over end" and "stop end". When inspecting, use the plug gauge "over end" to check the hole, "over end" can enter the hole; use the plug gauge "stop end" to check the hole, "stop end" can not enter the hole, indicating that the workpiece is qualified, otherwise Is unqualified.

  Plug gauges are generally used to inspect inner holes with low precision requirements. Our company uses them when inspecting the inner diameter of the rough outer ring and the middle diameter of the dust-proof groove.

  Notes when using gauges:

  A. The dust and oil on the gauge and the workpiece must be removed before use, so as not to affect the measurement accuracy.

  B. Do not use too much force when measuring, but put it into the measuring part evenly, and see the measurement results of "over end" and "stop end".

  C. Three parts of the parts should be checked when measuring.