Field of invention

The present invention is related to an integrated gear drive system used to drive both the oil pump assembly and Balancer shaft assembly which are used in reciprocating piston engine.

Background of invention

In piston engine, a balancer shaft is an eccentric weighted shaft which offsets vibrations in engine designs that are not inherently balanced. The oil pump supplies the oil throughout the engine components for proper lubrication.

Balancer shafts are most common in inline cylinder engines for balancing which, due to the asymmetry of the engine design, have an inherent vibration which cannot be eliminated no matter how well the internal components are balanced. This vibration is generated because the movement of the connecting rods in inline engine is not symmetrical throughout the crankshaft rotation; thus during a given period of crankshaft rotation, the descending and ascending pistons are not always completely opposed in their acceleration, giving rise to a net vertical inertial force.

The Oiling system addresses the need to properly lubricate an engine when it's running. Properly lubricating an engine not only reduces friction between moving parts but is also the main method by which heat is removed from pistons, bearings, and shafts. Failing to properly lubricate an engine will result in engine failure. The oil pump forces the motor oil through the passages in the engine to properly distribute oil to different engine components. Oil is drawn out of the oil sump through a wire mesh strainer that removes some of the larger pieces of debris from the oil. The flow caused by the oil pump ensures the distribution of Oil around the Engine.

Objects of invention

The main object of the present invention is to provide an integrated gear drive system used to drive both the oil pump assembly and Balancer shaft assembly.

Yet another object of the present invention is to provide improved packaging of the oil pump and balancer shaft by actuating it by integrated gear drive system.

Brief description of drawings

According to the present invention,

Figure 1 shows Belt drive system for Oil pump & balancer shaft. (Prior Art)

Figure 2 shows Chain drive system for Balancer shaft. (Prior Art)

Figure 3 shows Gear drive system for Balancer shaft. (Prior Art)

Figure 4 shows an Integrated Gear Drive System for Oil Pump and Balancer Shaft
Assembly.

Figure 5 shows Balancer Shaft Assembly Details.

Figure 6 shows an Oil Pump Assembly Details.

Figure 7 shows an Integrated Gear Drive System for Oil Pump and Balancer Shaft
Assembly.

Figure 8 shows balancer shaft oil supply passage

Brief description of invention

In prior applications, either belt or chain drive was used for Oil Pump assembly & balancer shaft assembly. In some of the new engines individual gear drive systems are used for Oil Pump assembly & balancer shaft assembly (separate gear drives). The figures 1-3 show the different types the drive system are being used for both the systems.

The invention relates to an integrated gear drive system used to drive both the oil pump assembly and Balancer shaft assembly. An integrated gear drive system is used to drive both the Oil pump assembly and Balancer shaft assembly in a reciprocating piston engine. In piston engine, a balancer shaft is an eccentric weighted shaft which offsets vibrations in engine designs that are not inherently balanced. The oil pump driven by the crankshaft supplies the oil throughout the engine.

The Invention accounts for the elimination of different drive system for Oil pump & Balancer shaft assemblies' and it also reduces the Oil Sump height thereby reducing the engine mass and cost. The gear drive provides noiseless, smoother, better strength and high reliable operation and it is also an example for design for easy assembly and service (DFA & DFS).

The basic concept has a balance shaft rotating in opposite direction to the crank shaft at the same crank speed. Equally-sized eccentric weights on the shaft are sized and phased so that the inertial reaction to their counter-rotation cancels out in the horizontal plane, but adds in the vertical plane, giving a net force equal and predetermined out-of-phase angle with the undesired second-order vibration of the basic engine, thereby canceling it.

Detailed description of invention

The invention relates to an integrated gear drive system used to drive both the oil pump assembly and Balancer shaft assembly (Figure 4 ), which are used in reciprocating piston engine. In piston engine, a balance shaft (8) is an eccentric weighted shaft which offsets vibrations in engine designs that are not inherently balanced. The oil pump driven by the crankshaft supplies the oil throughout the engine.

The integrated gear drive system contains four gears namely Crank Gear (1), Oil Pump Gear (2), Idler Gear (3) and Balancer Shaft Gear (4). Crank gear (1) is press fitted in the crankshaft which is the primary drive of the engine. Crank gear (1) is meshing with Oil pump gear (2) where Oil Pump gear is connected with Rotor of the pump. Oil pump gear (2) is meshing with Idler gear (3). This idler gear (3) is meshing with Balancer shaft gear (4) where the balancer shaft gear is connected with balancer shaft (8). Balancer shaft assembly comprises of a balancer shaft mounting bracket (6), balancer shaft gear (4) as shown in figure 5 and a rotatable balancer shaft carrying at opposite ends balance web/weights (7) which is used to minimize the unbalance forces that causes the vibration of the engine. Oil Pump sucks the oil from the Oil Sump through a wire mesh oil pump strainer (10) as shown in Figure 6); and lubricates the entire engine. An alignment mark (5) for proper mounting and positioning of the gears of the drive system is provided in the balancer shaft bracket (6) to ensure the correct alignment of the gear drive assembly.

The dot mark in the crank gear provides the correct assembly of crank gear with crank shaft so that the correct balancing will be ensured as shown in figure 4. The dot mark is provided in the balancer shaft which can be provided at any degree from the vertical axis for correct assembly as shown in figure 4. The axis of the balancer shaft gear and crank gear need not be in a same plane shown in below figure 4. The balancer shaft Bracket has internal passage for Oil supply to the balancer shaft from the Cylinder block shown in below figure 8.

When the engine is started, the crank gear (1) rotates and the Oil pump gear (2) maintaining a fixed gear ratio. When the Oil pump gear rotates, it actuates the internal rotor connected with the oil pump gear and the oil pump starts functioning. The balancer shaft rotates due to the Meshing of Idler gear (3) with the Balancer shaft gear (4). The Crank gear (1) and balancer shaft gear (4) have the same gear ratio to rotate at the same speed. Idler gear (3) is introduced to change the direction of the rotation so that so that the unbalance moment generated in crankshaft gets minimized by the balancer shaft (8).

The Invention accounts for the elimination of different drive system for Oil pump & Balancer shaft assemblies' and it also reduces the Oil Sump height thereby reducing the engine mass and cost. The gear drive provides noiseless, smoother, better strength and high reliable operation and it is also an example for design for easy assembly and service (DFA & DFS).

Any gear ratio of crank Gear / Oil pump Gear / Idler Gear / Balancer shaft Gear can be made based on the engine requirement The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

WE CLAIM :

1. An integrated gear drive system for oil pump and balancer shaft assembly comprising

an integrated gear drive system comprises of crank gear (1), oil pump gear (2), idler gear (3) and balancer shaft gear (4);

a balancer shaft assembly comprises of a balancer shaft mounting bracket (6), balancer shaft gear (4), balancer web (7) and a rotatable balancer shaft (8) adapted for rotating in opposite direction to the crank shaft at the same crank speed; and

at least one oil pump assembly (9).

2. The system and assembly as claimed in claim 1 wherein said crank gear (1) is meshing with oil pump gear (2) connected with rotor of the pump, oil pump gear (2) is meshing with idler gear (3) further meshing with balancer shaft gear (4) mounted on balancer shaft (8) such that a single gear drive system is used to drive both the oil pump assembly and balancer shaft assembly eliminating different drive system for oil pump & balancer shaft assemblies' and to reduce the oil sump height to reduce the engine mass and cost.

3. The system and assembly as claimed in claim 1 wherein said system and assembly are configured for eliminating different drive system for oil pump and balancer shaft assemblies for reducing over all engine weight and cost.
4. The system and assembly as claimed in claim 1 wherein said web mass (7) is mounted at an angle with respect to the crank shaft vertical axis and opposite to the direction of the eccentric mass in the balancer shaft and the balancer shaft gear is placed in between balancer shaft and web mass.

5. The system and assembly as claimed in claim 1 wherein said rotatable balancer shaft (8) is configured with balance web/weights (7) at opposite ends configured to minimize the unbalance forces that causes the vibration of the engine by the inertial reaction of their counter-rotation canceling out in the horizontal plane and adding in the vertical plane, giving a net force equal and predetermined out-of-phase angle with the undesired vibration of the basic engine and canceling it.

6. The system and assembly as claimed in claim 1 wherein said oil pump with a wire mesh oil pump strainer (10) is configured for pumping the oil from the oil sump for lubricating the engine.

7. The system and assembly as claimed in claim 1 wherein an alignment mark (dot mark) (5) is provided in the crankshaft and crank gear (6) to ensure the correct alignment of crank gear to crank shaft and an alignment mark (dot mark) (5) is also provided in the balancer shaft bracket (6) and balancer gear to ensure the correct alignment of the balancer shaft gear to balancer shaft bracket.

8. The system and assembly as claimed in claim 1 wherein said crank gear (1) is configured to rotate said oil pump gear (2) maintaining a fixed gear ratio to actuate the internal rotor connected with the oil pump gear and the oil pump starts functioning.

9. The system and assembly as claimed in claim 1 wherein said crank gear (1) and balancer shaft gear (4) have the same gear ratio to rotate at the same speed and said idler gear (3) is adapted for changing the direction of the rotation to minimize the unbalance moment generated in crankshaft by the balancer shaft (8) wherein axis of the balancer shaft gear and crank gear need not be in a same plane.

10. The system and assembly as claimed in claim 1 wherein a dot mark is provided in the balancer shaft which can be provided at any degree from the vertical axis for correct assembly and said balancer shaft bracket has internal passage for oil supply to the balancer shaft from the cylinder block.

11. The system and assembly as claimed in claim 1 wherein gear ratio for the gear train in any combination of crank Gear / Oil pump Gear / Idler Gear / Balancer shaft Gear is be made based on the engine requirement and interchangeability of gear positions.