Main shaft wear problem solution for jaw crusher2019-04-11

Summary:Main shaft wear problem solution for jaw crusherMost of the main bearings of the large jaw crusher are Ayong's open-type Huadong bearing, and the bearing lining

Main shaft wear problem solution for jaw crusher

Most of the main bearings of the large jaw crusher are Ayong's open-type Huadong bearing, and the bearing lining is made of babbitt. This bearing requires a high scraping technique. If the scraping is improper or missed, it will cause the bearing bush to be severely rubbed and burned. We will give a detailed description of the 900×1200mm simple pendulum jaw crusher. This type of jaw crusher is used in a mine in the country. For various reasons, the damage ratio of the main bearing is very high. We have thus concluded a set of method for changing the scraping and gap adjustment used in this case.

First, the work before the removal of the old tile

  • 1. Measure the thickness of the gasket of the old bearing pad joint surface; 2. Measure the level of the spindle
  • 2. Carefully check whether the spindle is smooth, if there are any defects such as rust and bumps, and if there is any idea, eliminate it.
  • 3. Measure the headspace, backlash and axial clearance of the old tile.

Second, the scraping of the bearing (very important)

The bearing bush should be scraped on the basis of the shaft, and the two are scraped by the inner hole scraper after grinding. The order of the scraping tile should be first scratched on the lower tile, then scraped up on the tile, then the entire tile is scraped, and finally the side gap and the oil storage point are scraped. The scraping of the bearing bush can generally be divided into three processes: rough scraping, fine scraping and fine scraping. When scraping, the principle of light weight, heavy weight, and large size should be adopted. When the bearing bush is scraped, not only the contact point and the contact angle are in accordance with the technical requirements, but also the top and side gaps are required to reach a delineated value.

The details can be divided into three steps:

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  • 1. The coarse and fine scraping of the upper and lower tiles first install the two lower tiles in the bearing housing, and then apply a layer of display agent (such as red powder, red Qiang oil, etc.) on the main shaft to mount the spindle on the bearing. Inside, and rolling two or three turns in the forward and reverse directions, then the main shaft is pulled out, and the rough shaving is performed according to the distribution of the colored dots on the bearing. The rough shaving stage can be scraped with a positive rake angle. The first few times, the hand can be heavier, and some metal is scraped off to speed up the scraping process. When the contact area reaches 50%, it is fine. In the fine scraping stage, small front angle scraping can be used. The tool path should be at an angle of 45° to the center line of the bearing bush. When scraping, the force should not be too large to prevent the blade from generating ripples. The scraped blade should be crossed to the left and right until the contact freckles in the contact angle range are evenly covered, and the spindle horizontality error is within 0.2 mm/m. The method and requirements for the scraping of the upper tile are basically the same as those for the coarse and fine scraping of the lower tile. The difference is that the upper tile is placed above the spindle for research.
  • 2. After the fine and fine scraping of the upper and lower tiles, the contact freckles are still large, and further research is needed. First, add the shim gasket on the upper and lower tile joints, install the main shaft, the upper tile and the positioning pin, tighten the screws, and make the spindle roll a few times in the normal running direction, then remove the upper tile and lift the spindle to carry out Fine research work. When scraping, it is best to scrape with a negative rake angle until the contact freckles on the contact surface meet the technical requirements (as shown in Table 3).
  • 3. After the scraping side clearance and the oil storage point are finished, the side clearance and the oil storage point should be scraped. When scraping the side clearance, a section should be left at both ends to prevent oil from flowing out from both sides of the tile, thus ensuring lubrication of the bearing bush. Between the contact and non-contact sectors of the tile, it should be gradually transitioned and not allowed to have significant boundaries. Then, the oil spot is scraped on the contact arc surface of the bearing bush, and the oil storage point is used for storing the lubricating oil. The oil storage point can be round or flat, the depth is generally 0.3~0.5 mm, the area is 15~30 mm2, and the total area should not exceed 1/5 of the contact arc surface.

Third, properly adjust the gap

The clearance of the bearing bush determines the thickness of the oil wedge and affects the running accuracy of the spindle. Excessive bearing clearance causes equipment vibration and reduces equipment life; if the bearing clearance is too small, it will cause burnt tiles. Therefore, the fair adjustment of the bearing clearance is an important issue that must be achieved to the delineated scale.

Fourth, the shaft and assembly

When assembling, first clean the bearing bush, journal, oil collector and lubricating oil pipeline. Then the main bearing shell, connecting rod and the like are assembled. When installing the V-belt, make it slightly looser than during normal operation. When commissioning, start the oil pump first, and make the oil supply slightly larger than normal operation.

Fifth, observe the current and oil temperature

If there is no significant increase in oil temperature and a significant increase in current during the test run, the test is successful and the equipment can be put into normal use.

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