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Engine overhaul, bearings must be replaced (Watts). KOYO bearings replaced, including matching and processing bearings in two phases.
Inspection and bearing, crankshaft bearing block hole of a match
1, before the selection of the bearing, you should first check that the housing bore is standards-compliant. Clean the housing and the cover, crankshaft and crankcase. Check that the bearing cap end face is flat, its flatness and maximum depth holes shall meet the requirements of the data.
2 pad at each end, as needed in the KOYO bearings cover gasket (copper or steel sheet), so that the housing bore mat to round was loaded onto the bearing cover and tighten the bolts, with diameter scale for measuring bearing bore diameter and roundness and cylindricity. More than 0.05mm such as roundness and cylindricity error, you should repair size boring dressing, as required.
3, size matching according to the repair of the crankshaft bearings. With specially made micrometer measurements of bearing thickness and its uniformity, bearing outer diameter to be commensurate with the dimensions of the housing bore, the deviation should not exceed 0.03mm. Tap the bearing with a metal object, such as issuing crisp sound, alloy combined with the floor well.
4, will match the appropriate bearings embedded inside the bearing housing and cover, verify that the bearings and bearing Fay (back and bore of the bearing fit level surface shall not be less than 85%), convex and bearing and grooves of the lid is chimeric, whether the oil holes in the bearing seat oil ducts connect.
5, bearings with bore after Fay, its two edges made higher by bearing plane 0.04~0.06mm so Fay packed can be better. Test method: install the bearing and bearing cover, moderately tighten the bolts up to the bearing with the base key, plug gauge into the bearing cap planes, measurement of bearing cap and cylinder bore surface gap at both ends, to 0.10MM gauge insert feeling fit, 0.15mm gauge cannot be inserted as appropriate. If the clearance is too large should be trimmed on both sides of the bearing, if too small, you need matching bearing separately.
6, bearing selection available at the request of the four words to sum up, that is based on journal selected KOYO bearings, bearing length standard; back smooth Tenon is good; elastic fit no sound dumb.
7, general note on the back of the bearing with reduced size levels ("-"), when there is no tag or inconsistent thickness, thickness check by measuring the bearing bearing level.
B, the crankshaft bearing matching method
This method is required to repair size crankshaft grinding, size of thin-walled bearing selection provides repair, after using a soft wire gauge or test, if the gap between the right, shall be eligible.
Method for the determination of its provisions is the w 13mm, d is equivalent to clearance under a thick paper placed on bearings, and the prescribed torque tighten the bearing cap bolts, then turn the crankshaft, with can turn and feel a certain resistance to qualify. Won't turn the clearance is too small, said it felt no resistance when turning the gap is too big.
If using a gauge of copper plate, its edges with oil stone polished, and coated with a little oil, test as described above: when you turn the crankshaft, not to go full circle, turned 80 ° ~90 °, so as to avoid damage to the bearing. Its compactness and do as described above.
Wire testing, use very soft wire diameter is slightly larger than required clearances, placed perpendicular to the axis of the bearing, on the required torque tighten the bearing cover; and then remove the bearing cover, remove the soft wire, measure the thickness of wire after pressure, that is, for bearing clearance value.
C, crankshaft bearings enamel (hinged) cutting
Crankshaft bearings enamel (hinged) away, is made up of soft (hinge) of cutting tools for processing, which come in many forms, but the basic principle is the same. Bearing alloy reamer adjustable reamers size activity two, large range of reaming diameter 62~66mm small diameter 47~54mm. Telescopic bracket also has two, is for hinge adjustment Rod centre line, centering and mounting. Hinged at one end of the rod handle, install reamer on the other side. It can hinge equipped with the crankshaft and camshaft bearings.
The operation is as follows:
1, the cylinder upside down on the work table. Ream when one or two, one or two have been given good bearing mount housing holes (including adjustment shims), three or four is not load bearing and after cleaning all of the KOYO bearing cap torque tightening, as required.
2, clean hinge telescopic rod and bracket holes and coated with oil, each of the two telescopic bracket at three or four in the housing bore locating (if the hole diameter is greater than the telescopic mounts when the maximum diameter, with increasing diameter of the spacer blocks). And then insert the telescopic bracket toggle holes in the bearing reamer into activities among two or three road.
3, try reaming. Active reamer into the second line of bearing hole in the elongation of the blade to exit after contact with the bearing, then pull the blade 0.02mm, turn the toggle lever clockwise, try reaming bearing one or two road.
Number 4, determine the amount of rubbing and rubbing. After you try one or two bearing hinge, inside and outside diameter micrometer measure one or two dimensions and bearing crankshaft hole size, difference between the two numbers combined with clearance (0.03~0.06) for a total amount of rubbing. In order to reduce the surface roughness of bearing, maximum amount of rubbing should be around 0.15mm, finally a knife should be at around 0.05mm, according to the total amount of rubbing and number of these principles determine the reaming.
5, reaming, three or four bearings, position the telescopic bracket in place one or two bearings (hinged when not one or two bearing remove bearing cover), reaming, as described above, three or four bearings.
6, after reaming completion, the bearing should be carefully examined, all eligible, reaming tool removed, scrape with a scraper bearing edges and burrs of the oil holes, oil tank, etc, and make a mark with the order and orientation, to rabbits and then when confused or turned upside down.
D, the crankshaft bearing scraping
Scraping crankshaft bearing journal contact area on the basic technology, and surface requirements, tightness, and handling of the relationship between, with the connecting rod bearings are basically the same. Connecting rod bearing is a single match, and crankshaft bearings are a few crank bearing support with a crankshaft, crankshaft bearing that calls for scraping of the road centre line must be the same. Therefore, first with horizontal correction and then grind the bearings.
1 correction, horizontal lines
① the cylinder upside down on the bench, clean the crankshaft flange, matching good bearing, mounted on the appropriate housings, and adapt to the bearing cap bolt 8~10MM thick iron plate clamping the bearing back at both ends, do not exceed crank bearing alloy layer, or by pressure of the weight of the crankshaft itself to make it stable.
② the crankshaft apply a thin layer of bearing blue, will crank into the housing, do not load bearing cap, turn the crankshaft a few weeks, remove the crankshaft, to see each bearing contacts, contact slightly down at both ends of each position is normal. If the exposures are inconsistent, but not many difference, scraping can repair bearings will be higher than some, if the difference is too large, or individual KOYO bearings cannot be contacted, should be optional separately.
③ the contact marks on the road bearing heavy scrape, repeat these steps until the correction to the piece on the bearing surface closer to the Middle, to ensure that the bearings on the same horizontal line, and then remove the clamping plate.
2, shave and enjoy the road bearing
① install crankshaft, pads into the proper (or the original) gasket, bearing cap by Mark fitted with a good Bush. Four press 2, 3, 1, 4, seven by 4, 2, 6, 3, 5, 1, 7, tighten bolts in the order a little. When tightened, turn the crankshaft a few slightly loose bolts on the road and then another. Each has been completed, remove the crankshaft bearing caps in all, viewing prints scratch. Scraping method has the same scratch connecting rod bearing.
② scraper bearings must be repeated more than once, each bearing cap bolts should be gradually increased to the same torque tightening and adjustment by the tightness of gaskets. Scraping order: If three bearing middle school; one or three of four road school, one of the seven, four or seven road, remaining together every school, then scrape.
③ experience demonstrated to be careful to maintain two contact surfaces; access to good, poor contact, poor should shave, good. After shave tie up and down repeatedly, the crankshaft bearing and axle journal the capital rely on timely, then tighten the bolts on the required torque, fine shave of the upper and lower bearings, and so on until the technical requirements.
④ After scraping bearing contact surfaces shall be not less than 75%, shall last not less than 85% to prevent oil spills.
| Product Model | Inside Diameter | Outside Diameter | Thickness |
| 7236BDB NSK | 180 | 320 | 52 |
| 7236ADB NSK | 180 | 320 | 52 |