Tham khảo tài liệu 'manual gearbox design part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 156 Manual Gearbox Design out. This area of the tube is covered with a fine mesh brass gauze and it is also advisable to fit a rod-type magnet up the centre of the tube. The purpose of this magnet is to collect the small pieces of steel which are removed from the corners of the face dogs during quick gear changes and are small enough to pass through the brass gauze. The oil from the pump is delivered through cast and machined galleries in the gearbox casings. The method usually adopted to lubricate the bearings in the free-running gears is to feed oil up the bore of the shaft which carries the free-running gears by means of an oil jet machined into one of the drilled oil galleries. The opposite end of the shaft bore to the oil jet should be fitted with a restrictor sleeve to ensure that oil is retained in the bore. Drilled holes in the shaft through to the inside of the bore relief diameter in the engaging dog sleeves directly inside the area that carries the engaging dog ring ensure that the oil centrifuges into this relief bore which then passes into the bearings through holes drilled from the bearing diameter into the relief bore. The oil having passed through the bearings centrifuges outwards lubricating idler gear thrust faces and retaining flanges before returning to the sump. Oil is fed through a further gallery running parallel with the internal gear shafts and through an oil jet from this gallery that feeds one pair of the internal gears . a four-speed gearbox has four oil jets and a five-speed gearbox uses five oil jets. An additional oil jet is used to lubricate the final drive gears. The location of the oil feed to the internal gear ratios and the final drive gears has for some time created controversy. The debate mainly centres on where the oil from the jets should be directed - should it be before the gear teeth mesh or after the gear teeth mesh and should the oil be sprayed on from a straightforward jet or from an oval fan-type spray. Research and
