LUBRICATION PUMP

FIELD OF THE INVENTION

[0001] The present invention relates generally to a lubrication pump and more particularly, but not exclusively, to a drive system for a lubrication pump disposed in an internal combustion engine.

BACKGROUND OF THE INVENTION

[0002] An automotive vehicle is powered by an internal combustion engine for propelling the vehicle forward. The engine has a lubrication pump located internal to a crankcase and adapted to force a lubricant through the engine passages to distribute the lubricant to various engine components including piston, crankshaft bearing, cam shaft, valves, valve seats, rocker arm assembly and rocker shaft. Proper lubrication of the engine not only reduces friction between moving parts but also removes the heat generated from it.

[0003] The lubrication system is driven by a drive system. When the lubrication pump is disposed near the crankshaft, the lubrication pump drive system may include a drive gear mounted on the crankshaft and a driven gear attached to the lubrication pump shaft. The location of lubrication pump near the crankshaft enables 'direct gear meshing' between the drive gear and driven gear and thereby getting the drive to pump the lubricant. Further, the drive gear may be common for lubrication pump driven gear as well as for one more gear provided on the clutch housing which drives the transmission gears to transmit the engine power. In some drive systems, two separate drive gears are mounted on the crankshaft, one for driving the lubrication pump driven gear and the other for driving the gear mounted on the clutch housing.

[0004] However, due to engine layout requirements, sometimes the lubrication pump is located away from the crankshaft. In this case, the lubrication pump drive system uses a chain drive arrangement to operate the lubrication pump located at a distance from the crankshaft as shown in FIG. 1. The chain drive arrangement comprises of a first chain wheel connected to the lubrication pump shaft and a second chain wheel connected to the clutch shaft. A chain connects the first chain wheel with the second chain wheel. The use of chain drive arrangement, however, results in certain disadvantages. It causes wear and tear of the chain and may result in transmission losses. Chain tensioners are employed to prevent substantial chain slack that may occur due to continuous use thereby increasing the overall manufacturing cost of the engine. Additionally, use of chain and chain tensioners make the crankcase heavy, expensive and increase the number of components present within.

SUMMARY OF THE INVENTION

[0005] The present subject matter is directed to overcoming all or any of the problems as set forth above and thereby to obviate a lacunae in the prior art. It is hence an object of the present subject matter to provide a simple, inexpensive, mechanically operated drive system to operate a lubrication pump when the lubrication pump is located away from the crankshaft due to engine layout requirements.

[0006] The present invention relates to a drive system comfigured to drive a lubrication pump in a four cycle internal combustion engine. The drive system comprises a first interlocking member, mounted on or connected to, a lubrication pump shaft; a second interlocking member, mounted on or connected to a clutch shaft; a lantern wheel interposed between and continuously engaged with the first interlocking member and the second interlocking member wherein the first interlocking member is driven by the drive received from the lantern wheel.

[0007] The foregoing objectives and summary is provided to introduce a selection of concepts in a simplified form, and is not limiting. To fully appreciate these and other objects of the present subject matter as well as the subject matter itself, all of which will become apparent to those skilled in the art, the ensuing detailed description of the subject matter and the claims should be read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0008] The above and other features, aspects and advantages of the subject matter will be better understood with regard to the following description, appended claims and accompanying drawings where:

FIG. 1 shows a chain drive arrangement for operating a lubrication pump according to prior art.

FIG. 2 shows a side view of an internal combustion engine according to present subject matter in a state where the crankcase cover has been removed.

FIG. 3 shows a detailed side view of a drive system according to the present subject matter.

FIG. 4 shows an exploded view of the drive system of FIG. 2 according to the present subject matter.

DETAILED DESCRIPTION OF THE INVENTION

[0009] The present subject matter as described herein relates to a drive system for driving a lubrication pump 'not' located in the immediate vicinity of the crankshaft due to engine layout requirements. The drive system for the lubrication pump is illustrated now. FIG. 2 shows a side view of a four cycle internal combustion engine in a state where the cover of a crankcase 7 has been removed. The drive system configured to drive a lubrication pump (not shown) comprises of a first interlocking member 3, a second interlocking member 1 and a lantern wheel 5; and is located internal to the crankcase 7. The first interlocking member 3 is spaced apart from the second interlocking member 1 and not directly meshed with each other. The first interlocking member 3 is mounted on, or continuously engaged with, a lubrication pump shaft 4. The lubrication pump is mounted on, or connected to, same lubrication pump shaft 4. The second interlocking member 1 is mounted on, or continuously engaged with, a clutch shaft 15 of the internal combustion engine. The clutch shaft 15 and the lubrication pump shaft are spaced apart from each other due to engine layout requirements and are not in direct meshing. Therefore, to drive the lubrication pump, the drive system also comprises of a lantern wheel 5 interposed between and continuously engaged with the first interlocking member 3 and the second interlocking member 1. The lantern wheel 5 is mounted to or connected with a lubrication pump shaft 4. Through the lantern wheel 5, the drive is transmitted from the clutch shaft 15 to the lubrication pump shaft to drive the lubrication pump.

[00010] According to an aspect, the lantern wheel 5 has a plurality of rollers 9 supported on pins 10 which are riveted on a flange of the lantern wheel 5 at a calculated pitch diameter (FIG. 4). Through these rollers, the lantern wheel is operatively engaged with the first interlocking member 3 and the second interlocking member 1.

[00011] Further, the lantern wheel 5 is supported on a lantern wheel shaft 8 which is rotatably supported at an appropriate place in the crankcase 7 on a holder plate 6. The holder plate 6 is fixed to the crank case 7 and is protruded inclinedly upwards to form a protruding portion 11. The protruding portion 11 has a threaded opening for incorporating the lantern wheel shaft 8 (FIG.4).

[00012] The transfer of drive form the clutch shaft to the lubrication pump is now explained. During the reciprocatory motion of the engine, the clutch shaft 15 rotates thus rotating the second interlocking member 1. Through the lantern wheel 5 interposed in between, the drive from the clutch shaft 15 is transmitted to the first interlocking member 3. The direction of rotation of the second interlocking member 1 and the first interlocking member 3 is same. The firsT interlocking member 3 then drives the lubrication pump shaft 4 which further drives the lubrication pump.

[00013] The location of the lantern wheel 5 is chosen such that at least one of the rollers 9 is always in contact with the second interlocking member 1 and at the same time one of the other roller disposed at the pitch circle of the lantern wheel 5 is in contact with the first interlocking member 3. This enables the drive to be transmitted from the second interlocking member 1 to the first interlocking member 3 and further to the lubrication pump shaft 4 which ultimately drives the lubrication pump. According to an aspect, the lantern wheel 5 is located at a side of the crankcase 7 due to space constraints. By being sidely disposed, the rotating axes of the lantern wheel 5, the first interlocking member 3 and the second interlocking member 1 respectively form an imaginary triangle and space is saved inside the cluttered crankcase 7 (FIG.3).

[00014] According to another aspect of the present invention, the first interlocking member and second interlocking member may use any suitable parts, including, but not limited to, sprockets, pulleys or any combination thereof. The drive system as a whole is driven by a suitable driving force produced by the engine, such as rotational outputs of the crankshaft (clutch shaft). The drive mechanism may be coupled to the driving force, such as the crankshaft directly or indirectly, via any suitable mechanism, such as shafts. Such internal combustion engine with the said lubrication pump drive system may be used to power any system, preferably an automotive vehicle.

[00015] The present subject matter and its equivalent thereof offer many advantages, including those which have been described henceforth. The drive system eliminates the need of a chain drive for transmitting the power from the clutch shaft to the lubrication pump shaft, when the lubrication pump is located away from the clutch shaft and not directly engaged with it. With the removal of chain drive, the requirement of chain tensioner is also eliminated which reduces the cost. Advantageously, the aforementioned lubrication pump drive system also eliminates the weight of the chain drive which makes the crankcase heavy and reduces fuel efficiency. It is a simple, inexpensive, mechanically operated system to drive the lubrication pump. The direction of rotation of the lubrication pump is retained as it is which does not require changes in the pump inlet and outlet.

[00016] The present subject matter is thus described. The description is not intended to be exhaustive nor is it intended to limit the invention to the precise form disclosed. It will be apparent to those skilled in the art that the disclosed embodiments may be modified in light of the above description. The embodiments described are chosen to provide an illustration of principles of the invention and its practical application to enable thereby one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore the forgoing description is to be considered exemplary, rather than limiting, and the true scope of the invention is that described in the appended claims.

We claim:

1. A drive system located inside a crankcase 7 of a four cycle internal combustion engine and configured to drive a lubrication pump, comprising: a rotatable first interlocking member 3 mounted on a lubrication pump shaft 4, a rotatable second interlocking member 1 mounted on a clutch shaft 15 of a four cycle internal combustion engine, a lantern wheel 5 interposed between and continuously engaged with the first interlocking member 3 and the second interlocking member 1, wherein the first interlocking member 3 is driven by the drive received from the lantern wheel 5, and drives the lubrication pump connected to the first interlocking member 3 and located away from the clutch shaft 15.

2. The drive system as claimed in claim 1, wherein the lantern wheel 5 is mounted on, or connected to, a lantern wheel shaft 8.

3. The drive system as claimed in claim 2, wherein the lantern wheel shaft 8 is rotatably supported on a protruding portion 11 of a holder plate 6 fixed to a crankcase 7.

4. The drive system as claimed in claim 1, wherein the lantern wheel is disposed at a side of, and internal to, the crankcase 7.

5. The drive system as claimed in claim 1, wherein the first interlocking member 3 and the second interlocking member 1 are sprockets.

6. The drive system as claimed in any of the preceding claims, wherein the internal combustion engine powers an automotive vehicle.