Automotive oil pump structure

Function: increase the oil pressure to ensure that the oil circulates continuously in the lubrication system and delivers a sufficient amount of oil to the lubrication part at a high enough pressure at any engine speed.

At present, the engine lubrication system is widely used in the gear type oil pump and rotor type oil pump two kinds.

1. Gear type oil pump

   Gear oil pumps are divided into two types: external gear oil pumps and internal gear oil pumps.

   ①External gear oil pump. The external gear oil pump is characterized by simple structure, convenient processing, reliable operation and long service life. It is mainly composed of a driving shaft, a driving gear, a driven shaft, a driven gear, and a casing. Two gears with the same number of teeth mesh with each other and are installed in the casing. The radial and end clearances between the gear and the casing are small. The driving shaft is keyed to the driving gear, and the driven gear is vacantly sleeved on the driven shaft.

            

    

   When working, the driving gear drives the driven gear to rotate in reverse. When the two gears rotate, the oil filled between the tooth slots of the gears is carried from the oil inlet chamber to the oil outlet chamber along the oil pump casing wall. On the side of the oil inlet chamber, a vacuum is generated due to the gear disengagement and the oil being continuously brought out, so that the oil in the oil pan enters the oil inlet chamber through the filter under the action of atmospheric pressure, while on the side of the oil outlet chamber due to The gears come into mesh and the oil is continuously brought in to produce a squeezing action, and the oil is pumped out with a certain pressure.External mesh oil pumps are characterised by simple structure, easy processing, reliable operation and long service life.

      ② Internal gear oil pump. Internal meshing oil pump structure. The driving gear drives the driven ring gear to rotate, and the volume of the chamber on the side     where the outer gear and the inner gear disengage becomes larger. Under the action of negative pressure, the oil enters the chamber; continues to rotate, and   the oil storage chamber near the oil discharge port The volume will gradually decrease until it is fully engaged and the oil is expelled.

   2. Rotor oil pump

     The rotor type oil pump is composed of a housing, an inner rotor, an outer rotor and a pump cover, etc. The inner rotor is fixed on the rotor shaft with keys or pins, and is directly or indirectly driven by the crankshaft gear. The eccentric distance between the centers of the inner rotor and the outer rotor is e, and the inner rotor drives the outer rotor to rotate together in the same direction. The inner rotor has 4 convex teeth, and the outer rotor has 5 concave teeth, so that the inner and outer rotors rotate in the same direction but not synchronously.

      The tooth profile of the rotor is designed so that when the rotor rotates to any angle, the tooth profile of each tooth of the inner and outer rotors can always form a point contact with each other. In this way, four working chambers are formed between the inner and outer rotors, and the volumes of these four working chambers are constantly changing as the rotor rotates. In the cavity on one side of the oil inlet passage, due to the disengagement of the rotor, the volume gradually increases, a vacuum is generated, the oil is sucked, the rotor continues to rotate, and the oil is taken to the side of the oil outlet passage. At this time, the rotor just enters the mesh, so that the volume of this cavity decreases, the oil pressure increases, and the oil is squeezed out from between the teeth and sent out through the oil passage. In this way, with the continuous rotation of the rotor, the oil is continuously sucked in and pressed out.

      The characteristics of the rotor type oil pump are compact structure, light weight, small size, large pump oil volume, good oil supply uniformity, and low cost.