Can change the internal and external two sets of rotary line pump capacity oil pump

Yamada's 40th Tokyo Motor Show (opened to the public from October 27th to November 11th, 2007) exhibited two sets of internal and external Trochoid Pumps in a single casing, which can be stopped as needed. A group of variable capacity oil pumps. The oil pump forms teeth on the three sets of rotors, and the rotary line pump is formed by the meshing of the respective teeth.

Among the three sets of rotors, the innermost inner rotor forms teeth on the outer side of the shaft, thereby forming a rotary power input shaft. The middle rotor forms teeth on both inner and outer sides, and is rotated by the inner and outer sides. The outer rotor forms teeth on the inner side, and the outer diameter side is circular, rotating the inner side of the outer casing. The space sandwiched by the inner rotor and the middle rotor forms a main pump, and the portion sandwiched by the middle rotor and the outer rotor forms a sub-pump.

When the engine rotates at a low speed, the main pump and the sub-pump are arranged in parallel and the flow rate is large. After the high-speed rotation, when the flow rate is too large, the outlet of the auxiliary pump is switched by the slide valve to return the oil to the oil pan. The main and auxiliary pump capacity of the prototype product is 1 to 1. Can be halved as needed. This ratio is freely determinable.

In the recently introduced engine, the number of mechanisms requiring variable oil pressure such as variable valve timing is increasing, and the oil pressure required for idling becomes large. If the oil pump is designed to compensate for the lack of oil pressure during idling, the displacement pump will have a proportional increase in flow rate with the rotational speed, so the flow rate tends to be excessive at high speeds.

In terms of the variable capacity pump that is the solution to this problem, there have been designs for two small pumps side by side. However, to achieve this solution, the number of components such as rotors and seals must be doubled in the past, the structure is very complicated, and the losses are also serious. With the combination of internal and external, the middle rotor can use both inner and outer sides to achieve a waste-free design. In the case of a larger diameter rotary drum pump, the central portion is prone to form a dead zone, so space utilization can be improved by accommodating another small-diameter rotary line pump.

The prototype is driven by a chain and is placed at a lower position than the crankshaft. The acceleration and deceleration demonstration is not performed. In fact, it can accelerate and decelerate, and can also be directly driven by the crankshaft.