Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1991-06-28
1992-09-15
Miller, Carl S.
Internal-combustion engines
Charge forming device
Fuel injection system
123495, 417372, F01M 3900
Patent
active
051468956
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention is based on a fuel injection pump for internal combustion engines.
In a known fuel injection pump of this type (German Patent 1 263 397), the transmission chamber is completely filled with lubricating fluid, and the motor oil from the engine oil circulation loop is typically used as the lubricating fluid. Because of the relatively high viscosity of motor oil, the limit rpm of the cam transmission, that is, the rpm of the drive shaft at which the eccentric disk "derails" and no longer rolls off the rollers of the roller race, is quite low. This limits the use of this fuel injection pump to low-speed Diesel engines.
In another known fuel injection pump (German Published, Unexamined Patent Application 36 05 452), the transmission chamber is only partly filled with lubricating medium, because a drainage bore is disposed in it in a spatially suitable manner; as a result, the rpm limit of the cam transmission can be increased substantially. However, it has been found that at high drive rpm, the lubricating fluid collects in the outer region of the driving mechanism part, and the driving claws of the claw clutch, which are located near the center and must transmit considerable torque, are not lubricated. The result is rapid wear and a disproportionately short service life of the fuel injection pump.
ADVANTAGES OF THE INVENTION
The fuel injection pump according to the invention has an advantage over the prior art that because the transmission chamber is only partly filled, again with lubricating medium, the rpm limit of the cam transmission is quite high, and even in the region of the high drive rpm of the drive shaft, which is near the rpm limit, the heavily loaded drive faces of the claw clutch are adequately lubricated. This increases the service life of the fuel injection pump drastically.
Advantageous further developments of and improvements to the fuel injection pump disclosed herein are possible with the provisions recited herein; the term "lubricating oil" will be used as a synonym for all types of lubricating media, and motor oil is used preferably.
In a preferred embodiment of the invention, the flow of lubricating oil compelled by the lubricating oil pump from the lubricating oil groove to the lubrication openings in the claw faces of the claw clutch is attained in a particularly advantageous manner by providing that the drive shaft has an axial blind bore, which communicates with the lubricating oil groove via a radial bore and is closed on the discharge end. From the blind bore, inclined bores lead into the driving claws of the drive shaft, which are closed at the face end. Leading from each inclined bore is one distributor bore into whichever claw faces of the driving claws are transmitting torque in the intended direction of rotation of the drive shaft. The discharge openings of the distributor bores in the claw faces form the lubricating oil openings. The coupling of the driving claws of the drive shaft to the driven claws of the eccentric disk, which is connected to the distributor piston in a manner fixed against relative rotation, is effected via a clutch disk embodied as a cross-shaped disk. In order that the claw faces of the clutch disk that transmit a driving torque will also be adequately lubricated, second distributor bores extend in the clutch disk from the claw faces of the clutch claws that rest on the driving claw faces that have the lubricating oil openings as far as the claw faces of the same clutch claws, which are in the lead in the direction of rotation.
In a further embodiment of the invention, first distributor bores lead from all the claw faces of the driving claws to the inclined bores, and with their discharge openings form the desired lubricating oil openings in the claw faces. In the same way, all the clutch claws are penetrated by second distributor bores, which each discharge in the two claw faces defining the clutch claws, so that each forms one lubricating oil opening there. In this embodiment, all the claw faces are supplie
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patent: 4697565 (1987-10-01), Kabayashi et al.
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patent: 4873956 (1989-10-01), Fehlmann et al.
patent: 5000668 (1991-03-01), Nakamura et al.
patent: 5007400 (1991-04-01), Babitzka
Eblen Ewald
Fehlmann Wolfgang
Laufer Helmut
Greigg Edwin E.
Greigg Ronald E.
Miller Carl S.
Moulis Thomas N.
Robert & Bosch GmbH
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