US20040108167A1

US20040108167A1 - Variable resistance control of a gear train oil pump

Info

Publication number: US20040108167A1
Application number: US10/310,347
Authority: US
Inventors: Christopher Elliott
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2002-12-05
Filing date: 2002-12-05
Publication date: 2004-06-10

Abstract

An apparatus and method for controlling a flow of oil. The apparatus and method includes a gear train having at least two gears engaged in meshed contact with each other, an inlet port for receiving a supply of oil to the gear train, an outlet port for providing an exit path for the oil from the gear train, a variable valve located at one of the inlet and outlet ports, and a controller electrically connected to the variable valve for operating the valve to control the flow of oil through the gear train.

Description

TECHNICAL FIELD

This invention relates generally to a method and apparatus for controlling noise of a gear train and, more particularly, to a method and apparatus for controlling oil flow through a gear train to control noise of the gear train.

BACKGROUND

Gear trains having two or more gears meshed together are used to perform a wide variety of work tasks, such as driving engine components, machinery, and the like. Each gear has a set of teeth that must mesh with a corresponding set of teeth of at least one other gear such that contact is close enough for efficient power transfer, yet not so close that the teeth bind and prevent smooth movement of the gears. A consequence of the required tolerances of the contacts is that much noise is created by the teeth as they engage one another. For example, noise created by a gear train in an internal combustion engine accounts for a significant percentage of the total generated engine noise.

Many attempts have been made to reduce the noise generated by gear trains. One method used is to introduce oil between the teeth just before they engage one another. The oil fills the gaps between teeth and is forced out as the teeth engage. The presence of oil between the teeth reduces an amount of backlash, caused by the requirement to maintain some space between the teeth for smooth operation of the gears. Backlash causes noise from the metal surfaces of the teeth coming into contact with each other. The presence of oil acts as a filler to reduce the backlash and hence the noise.

Several examples exist in which gear trains are subject to oil between the teeth as they mesh. Primarily, the purpose of introducing the oil is to use the gears to pump the oil to other locations as the gears perform their normal functions. A few examples may be found in U.S. Pat. No. 1,083,329 to Lancia, U.S. Pat. No. 2,883,001 to Dierksen, U.S. Pat. No. 1,585,731 to Oakes, U.S. Pat. No. 4,662,490 to Yamakawa, and the like.

Previous attempts suffer from the disadvantage in that they are not designed to account for changing work conditions of the gear train, such as changes in load conditions. At times, gear train noise may be minimal and not require much dampening. During these times, the introduction of oil may adversely affect performance of the gears and it would be desirable to reduce or eliminate the introduction of oil. At other times, it may be desired to increase the amount of oil to the gears since operating conditions generate much more noise.

Furthermore, when a gear train is functioning as an oil pump, it may be desirable to control the flow of oil entering and/or leaving the gears so that the oil pump function of the gear train is variably controllable. Once again, this control may be a function of operating conditions of whatever machine the gear train is incorporated with. For example, under varying load conditions, a correspondingly varying amount of oil may need to be pumped to machine components.

The present invention is directed to overcoming one or more of the problems as set forth above.

SUMMARY OF THE INVENTION

In one aspect of the present invention an apparatus for controlling a flow of oil is disclosed. The apparatus includes a gear train having at least two gears engaged in meshed contact with each other, an inlet port for receiving a supply of oil to the gear train, an outlet port for providing an exit path for the oil from the gear train, a variable valve located at one of the inlet and outlet ports, and a controller electrically connected to the variable valve for operating the valve to control the flow of oil through the gear train.

In another aspect of the present invention a method for controlling a flow of oil through a gear train having at least two gears engaged in meshed contact with each other, an inlet port to the gear train, and an outlet port from the gear train is disclosed. The method includes the steps of determining a condition associated with the gear train, and controlling the flow of oil through at least one of the inlet and outlet ports as a function of the condition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of an internal combustion engine; [0010]
FIG. 2 is a diagrammatic illustration of a cutaway view of FIG. 1 showing an exemplary gear train; [0011]
FIG. 3 is a block diagram illustrating a preferred embodiment of the present invention; [0012]
FIG. 4 is a block diagram illustrating an alternate embodiment; and [0013]
FIG. 5 is a flow diagram illustrating a preferred method of the present invention.[0014]

DETAILED DESCRIPTION

Referring to the drawings, the specification, and the appended claims, an [0015] apparatus 100 and method for controlling a flow of oil is disclosed. The present invention pertains particularly to a gear train 201, for example a gear train drivably connected to a machine 101, such as an internal combustion engine 102. Although many types of machines may benefit from use of the present invention, for example manufacturing machines, electrically driven machines, and any other types of machines which use gear trains, the present invention will be described with reference to an engine for purposes of illustration.
FIG. 1 shows a [0016] typical engine 102 used for many purposes, such as providing power for transportation, electric power generation, and the like. It is well known that engines require constant lubrication to cool moving parts, reduce friction and take particles away from the surfaces of the moving parts. The need for constant lubrication requires oil to be delivered, i.e., pumped, to the moving parts.
FIG. 2 shows the [0017] engine 102 of FIG. 1, but with a gear train 201 exposed. In the embodiment of FIG. 2, the gear train 201 includes a crankshaft gear 202, a first idler gear 204, a second idler gear 206, a camshaft gear 208, an air compressor gear 210, a fuel pump gear 212, a water pump gear 214 and a pair of two-plane idler gears 216. The crankshaft gear 202 is driven by the engine 102, as is well known in the art. The crankshaft gear 202 in turn may drive the two-plane idler gears 216, which in turn may drive the first idler gear 204, which may drive the second idler gear 206, which may drive the camshaft gear 208.
Furthermore, the [0018] first idler gear 204 may drive the air compressor gear 210 and the fuel pump gear 212, and one of the two-plane idler gears 216 may drive the water pump gear 214.
The [0019] gear train 201 of FIG. 2 is but one example of a gear train for an engine. Other combinations of gear arrangements may be used. In addition, additional gears for other purposes may be added. Examples of other gear arrangements may include a camshaft gear being driven directly by a crankshaft gear, a crankshaft gear driving an idler gear which drives a camshaft gear, and the like.
Referring to FIG. 3, a block diagram illustrating a preferred embodiment of the present invention is shown. The [0020] gear train 201 is shown having a first gear 302, a second gear 304 and a third gear 306. The first, second, and third gears 302,304,306 are engaged in meshed contact with each other; that is, the teeth of the gears are engaged in contact. More particularly, the second and third gears 304,306 are shown engaged with the first gear 302. It is noted that any number of two or more gears could be used. For example, two, three, four, five, or any other number of gears could be used.
An [0021] inlet port 308 is provided for receiving a supply of oil to the gear train 201. An outlet port 310 is also provided for an exit path for the oil from the gear train 201. A variable inlet valve 312 is located at the inlet port 308, and a variable outlet valve 314 is located at the outlet port 310. However, both valves 312,314 need not necessarily be present. For example, the variable inlet valve 312 may be present at the inlet port 308, and no valve may exist at the outlet port 310. Alternatively, the variable outlet valve 314 may be present at the outlet port 310, and no valve may exist at the inlet port 308. Both the inlet and outlet valves 312,314 are preferably configured to control an amount of flow of oil, i.e., to controllably restrict the flow of oil when actuated.
A [0022] controller 316 is electrically connected to the inlet and outlet valves 312,314 and operates the valves 312,314 to control the flow of oil through the gear train 201. The controller 316 may be a microprocessor based electronic control module (ECM) such as is commonly used on machines, for example internal combustion engines. Preferably, the controller 316 may selectively operate the inlet valve 312, the outlet valve 314, or both valves 312,314 as needed to achieve the desired results.
FIG. 4 depicts an alternative embodiment. An [0023] inlet port 308 includes a variable inlet valve 312. A first outlet port 402 includes a first variable outlet valve 406, and a second outlet port 404 includes a second variable outlet valve 408. Preferably, the first and second outlet ports 402,404 are configured to deliver oil to separate locations.
The [0024] controller 316 is electrically connected to the inlet valve 312, the first outlet valve 406, and the second outlet valve 408. The controller 316 may selectively operate any or all of the valves 312,406,408 to achieve the desired results.
Although each of the [0025] inlet port 308 and the first and second outlet ports 402,404 are shown with corresponding valves 312,406,408 in FIG. 4, it is noted that not all ports need have a valve. More specifically, any one or more of the ports depicted in FIG. 4 may not have a valve included. Control of the flow of oil would be accomplished by any remaining valves.
The present invention is not limited to the two embodiments of FIGS. 3 and 4. For example, any number of inlet ports may be present, and any number of outlet ports may be present. Furthermore, variable valves may exist at any desired inlet and outlet ports in any quantity. In addition, it is not necessary for one controller to operate all valves. For example, a first controller (not shown) may control inlet valves, and a second controller (also not shown) may control outlet valves. [0026]
Industrial Applicability [0027]
Referring to FIG. 5, a flow diagram illustrating a preferred method of the present invention is shown. [0028]
In a [0029] first control block 502, a condition associated with the gear train 201 is determined. The condition may be any of a variety of parameters, such as a load on the gear train 201, a speed of rotation of the gears in the gear train 201, and the like. The condition may be relevant to an amount of noise generated by the gear train 201 as the teeth of the gears engage one another. For example, as the speed of rotation increases, the amount of noise created may increase.
The condition may also be associated with a desired amount of oil to be delivered from the [0030] gear train 201 to some other component (not shown). For example, an outlet port 310,402,404 may provide oil to a working component which requires varying amounts of oil as working conditions change. As a more specific example, a component may require varying amounts of lubricant as load conditions on the component change.
In a [0031] second control block 504, the flow of oil is restricted through at least one of the inlet and outlet ports 308,310,402,404 as a function of the determined condition. The flow of oil may be restricted into an inlet port 308 to restrict an amount of oil to the gear train 201. The flow of oil may also be restricted from an outlet port 310,402,404 to increase an oil pressure at the gear train 201.
Other aspects can be obtained from a study of the drawings, the disclosure, and the appended claims. [0032]

Claims

What is claimed is:

1. An apparatus for controlling a flow of oil, comprising:

a gear train having at least two gears engaged in meshed contact with each other;

an inlet port for receiving a supply of oil to the gear train;

an outlet port for providing an exit path for the oil from the gear train;

a variable valve located at one of the inlet and outlet ports; and

a controller electrically connected to the variable valve for operating the valve to control the flow of oil through the gear train.

2. An apparatus, as set forth in claim 1, further including an other variable valve located at an other one of the inlet and outlet ports.

3. An apparatus, as set forth in claim 2, wherein the controller is electrically connected to the other variable valve and is further adapted for operating the other variable valve to further control the flow of oil through the gear train.

4. An apparatus, as set forth in claim 3, wherein the controller is further adapted for selectively controlling at least one of the variable valve and the other variable valve.

5. An apparatus for controlling a flow of oil, comprising:

a gear train having a plurality of gears engaged in meshed contact with each other;

an inlet port for receiving a supply of oil to the gear train;

an outlet port for providing an exit path for the oil from the gear train;

a variable inlet valve located at the inlet port; and

a controller electrically connected to the variable inlet valve for operating the valve to control the flow of oil into the gear train.

6. An apparatus, as set forth in claim 5, further including a variable outlet valve located at the outlet port.

7. An apparatus, as set forth in claim 6, wherein the controller is electrically connected to the variable outlet valve and is further adapted for operating the variable outlet valve to control the flow of oil out of the gear train.

8. An apparatus, as set forth in claim 6, further including:

an other outlet port for providing an other exit path for the oil from the gear train; and

an other variable outlet valve located at the other outlet port.

9. An apparatus, as set forth in claim 8, wherein the controller is electrically connected to each of the variable outlet valve and the other variable outlet valve and is adapted for selectively controlling at least one of the variable inlet valve, the variable outlet valve, and the other variable outlet valve.

10. A method for controlling a flow of oil through a gear train having at least two gears engaged in meshed contact with each other, an inlet port to the gear train, and an outlet port from the gear train, including the steps of:

determining a condition associated with the gear train; and

controlling the flow of oil through at least one of the inlet and outlet ports as a function of the condition.

11. A method, as set forth in claim 10, wherein determining a condition includes the step of determining a condition associated with a load on the gear train.

12. A method, as set forth in claim 10, wherein determining a condition includes the step of determining a condition associated with a speed of rotation of the gear train.

13. A method, as set forth in claim 10, wherein controlling the flow of oil includes at least one of the steps of:

restricting a flow of oil into the inlet port to restrict an amount of oil to the gear train; and

restricting a flow of oil from the outlet port to increase an oil pressure at the gear train.

14. An apparatus for controlling a flow of oil through a gear train drivably connected to a machine, comprising:

at least one inlet port for receiving a supply of oil to the gear train;

at least one outlet port for providing a corresponding at least one exit path for the oil from the gear train;

at least one variable valve located at a select at least one inlet and outlet port; and

a controller electrically connected to each variable valve for selectively operating each variable valve to control the flow of oil through the gear train.

15. An apparatus, as set forth in claim 14, wherein the machine is an internal combustion engine.

16. An apparatus, as set forth in claim 15, wherein the gear train includes a plurality of gears associated with a transfer of power generated by the engine.

17. A method for controlling an amount of noise being generated by a gear train having at least one inlet port, at least one outlet port, and a supply of oil passing through the gear train from the inlet port to the outlet port, including the steps of:

determining a condition associated with the noise being generated by the gear train; and

restricting a flow of oil through at least one of the inlet and outlet ports as a function of the condition.