A Novel Configuration of Balancer Shaft for Multiple Additional Uses as an Idler and an Oil Pump Drive
1. TECHNICAL FIELD OF THE INVENTION
The invention relates to internal combustion engine with regard to layout and integration of various components. Innovative and novel configuration of balancer shaft provided for balancing the unbalanced mass of engine has been designed for multiple use such as operating oil pump and cam shaft on crankcase making the overall arrangement highly efficient, compact and very cost effective.
The configuration and lay out in this invention also provide rotating balancer shaft and oil pump to be handled by the same chain drive system in this invention that reduces the transmission losses and improves the efficiency of engine. The design also provides the first order mass balancing system on idler shaft thereby causing an overall reduction of vibrations.
2. BACKGROUND AND THE PRIOR ART
Balancer shaft is an essential component of an internal combustion engine. In automotive applications, it is often provided as a specific drive separately for balancing the reciprocating masses where a first order mass balancing system is required for reasons of rigidity and compactness as functional requirement.
Reduction of vibration and noise in an internal combustion engine is an important technological challenge. A major cause of vibration in a single cylinder engine is piston reciprocation. When operated in a mechanical device, the engine produces vibrations that are transmitted to the operator through the device. This vibration is often uncomfortable to the operator and produces fatigue. Even in devices not requiring a human interface, the engine vibration is undesirable because it causes maintenance problems and tends to reduce the useful life of the machine.

To some extent such vibrations can be reduced by providing the engine with a counterweight fixed on its crankshaft designed to cancel partially primary acceleration and deceleration forces on the piston assembly along the piston axis. However, the counterweights produce their own lateral vibrations, thus limiting the extent of elimination of undesirable vibrations present in the running engines.
A balance system for implementation within an engine crankcase, as well as an engine employing such a system and a method of balancing forces as performed by such a system are disclosed in a recent patent application US 2009/0229559AI
Similarly the Japanese Patent Publication No. JP-A-2003-56647 discloses an example of another balancer device wherein the balancer shaft is journalled at its both ends through bearings disposed within a crankcase and orientated in parallel with a crankshaft. The balancer weights are mounted on the balancer shaft on axially outer sides relative to the bearings.
A European patent EP1628042A1 with equivalent patents in US, Japan and China proposes the balancer shaft to have longitudinal ends supported by a crankcase at its both ends through bearings. The shaft is disposed parallel to the crankshaft and the engine includes a plurality of balancer weights.
The crankcase assembly by itself requires a range of other considerations besides control of vibration and noise. Appropriate layout of various components to function properly in a crankcase often requires separate drives for each thereby increasing the complexity in engine design. Prudent design considerations are necessary to render the crankcase compact, functionally efficient and cost-effective.
The present invention brings out certain novel features of engine design by manipulating the balancer shaft for its multiple use such as driving oil pump beyond its tradition role of mass balancing. The novel configuration of various components linked through a single drive chain and reciprocating masses counter balancing each other in a programmable fashion renders the system compact and highly cost effective.

3. OBJECT OF INVENTION
The main object of this invention is to make the crankcase very compact and cost effective through an innovative lay out of its various components and employing multiple use of the balancer system including its use as a drive for the oil pump.
Another object of this invention is to operate an internal combustion engine with a first order mass balancing system on balancer shaft resulting into minimization of vibration and concomitant noise
4. SUMMARY OF THE INVENTION
The integrated balancer gear shaft is provided with the reciprocating masses for first order mass balancing that are placed at the two extreme ends at an equal distance from the middle plane of the shaft. The position of the reciprocating masses is locked with reference to crankshaft by bolting at the centre with suitable guide key arrangement; the balancing masses on the shaft are driven by sprocket mounted on the balancer shaft.
The balancer shaft in this invention is cylindrical with stepped portions at an equal distance form the central plane and is provided with bolts to lock the reciprocating masses at specified phase angles with key and washers. This is further integrated with the crankcase and is linked to an oil pump through a drive. The balancer shaft is driven by a sprocket which is mounted along with front balancer weight with position slot and mounted by bolts and two cylindrical bearing surfaces at each end behind the balancer weights.
The integrated shaft in this invention is adaptable for mounting on the cylinder block assembly and its multiple use thus offers the engine to be more compact and highly cost-effective than the prior art.
5. STATEMENT OF INVENTION
This invention provides a novel configuration of reciprocating masses on an integrated idler shaft locking their positions with reference to the crankshaft and providing appropriate solid surfaces on either ends of idler shaft for bearing arrangements. Such an arrangement is adaptable for integration

and mounting on the crankcase thus making it compact and cost-effective with reduced noise and vibrations.
This arrangement also allows reversing the direction of rotation from the crankshaft to the balancer shaft, which is necessary for a first order mass balancer. By anchoring the balancer weights opposite to each other staggered by 180°, the arrangement can also be suitably used as first order moment balancer.
6. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING(S)
Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
Figure 1 shows the schematic layout of idler shaft / balancer shaft integration with balancing masses along with crank shaft sprocket (1), cam shaft sprocket (2), balancer shaft sprocket (3) and oil pump sprocket (4), balancing masses (5 & 6), balancer shaft (7).as well as the chain (13) for traction of moving parts.
Figure 2 shows the view of balancer shaft (7) with a clear view of bearing surfaces
Figure 3 shows the integration of balancer shaft along with crank shaft sprocket (1), cam shaft sprocket (2), balancing shaft sprocket (3) and oil pump sprocket (4) and with the crankcase (8) firmly mounted on it
Figure 4 shows a view of integration of balancer shaft (7) with mass balancing system comprising of rear balancer mass (5) and front balancer mass (5)
Figure 5 shows a detailed view the integration of balancer shaft (7) with balancing masses (5 & 6) through balancer shaft sprocket (3) using keys, bolts and washers (10,11,12 etc.)

Example and Mode of Enablement
To validate industrial applicability of the disclosed invention, a proto type with design modification and layout of balancer shaft driving oil pump, camshaft and crankshaft as disclosed herein in the preferred embodiment was built in-house and 500 hrs of durability tests carried out in an engine test bed.
It was found that with the innovative layout disclosed in this invention, balancer did perform its primary function while at the same time the novel configuration of key sprockets placed around balancer shaft sprocket in common vertical plane and driven by a single chain worked perfectly smoothly representing a significant technical advance in engine design.
The lay out and integration of various components in the crankcase is so configured to offer the following functions and results:
i. Equitable balance of the first order of primary reciprocating balancing masses
ii. Desired configuration of all exposed sprockets with respect to each other and more
specifically with respect to oil pump sprocket that is amenable to be driven by a
common drive chain iii. Compact and very cost effective crankcase
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for the purpose of illustration in this disclosure and several 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 these variants with such modifications and alterations be included insofar as they come within the scope of the invention as claimed or equivalent thereof.

We claim:
1. The novel integrated balancer shaft with idler gear arrangement for internal combustion
engine that operates on the basis of first order mass balancing.
2. The balancer shaft / idler shaft with two cylindrical surfaces at the either end of the shaft for
bearing support as shown in Figure 2.
3. The balancer shaft with two semi cylindrical portions at equal distance from the centre and
with flat cylindrical surfaces with key arrangement for mounting the balancer masses to be
locked in a programmable position through bolt and washer and a phase lock pin as shown in
Figure 4 and 5.
4. The arrangement of balancer shaft, oil pump, cam shaft and crankshaft laid axially parallel to
each other in the crankcase with their respective sprockets protruding in the front in a
common vertical plane and parallel axes in a configuration pliable to be driven by single drive
chain passing through these sprockets as shown in Figure 3.
5. The internal combustion engine with the crankshaft fitted with a balancer shaft / idler shaft
6. The vehicle fitted with an internal combustion engine with said balancer shaft
7. The integrated balancer shaft assembly substantially as herein described with reference to
accompanying drawings