Internal Combustion Engine Shaft Mounting Device with Calibrated Lubrication Supply Passage

Abstract

A shaft mounting device for an internal combustion engine includes a bearing body having a mounting base for engaging an engine structure, and a semi-circular bore which is serviced by a lubricant distribution channel. An integral flow regulator, which is formed in place as a partial hydraulic obstruction, is located within the lubricant distribution channel. Because the flow restriction is integral, a separately machined flow restrictor is eliminated.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a shaft mounting device for use in an internal combustion engine. The inventive device provides both lubrication and retention to a rotating shaft within an engine, with the flow of lubrication being controlled by an integral flow restrictor contained within a bearing body portion of the shaft mounting device.

2. Disclosure Information

Modern pressure-lubricated, multicylinder internal combustion engines have literally dozens of bearings which must be supplied with lubricant by means of a centrally located oil pump. As part of the engine development process, the amount of lubricant reaching each bearing must be carefully metered so as to assure that all bearings are adequately lubricated, but without scheduling too much lubricant.

Oversupplying lubricant to engine bearings is disadvantageous for at least two reasons. First, an oversized oil pump will consume excessive energy, which degrades fuel economy. And, excessive churning of the oil by an oversize pump needlessly increases the amount of heat put into the oil. Thus, engine developers go through a tuning process in which the amount of oil going through various passages is carefully controlled. One method for controlling the amount of oil flowing through a passage is by placing a restrictor in the passage. FIG. 5 shows a prior art restrictor incorporated within bearing cap 100, which is maintained in contact with an engine part by means of screws 102. Bearing cap 100 has a lubricant channel, 104, which is provided with oil by means of lubricant supply port 108. The actual flow of oil through channel 104 is controlled by flow restrictor 110, which includes an axially drilled passage 112, and a radially drilled passage 114.

A problem with the prior art restrictor shown in FIG. 5 resides in the fact that restrictor 110 requires additional expense because of the need to machine passages within the restrictor. These fine passages must be carefully cleaned and inspected during manufacturing of the restrictor, and this adds more expense. Moreover, fine passageways may become plugged with contamination, thereby starving a bearing intended to be furnished with oil.

It is known to manufacture a bearing cap with a restrictor by starting with a part having an unmachined lubricant passage. A milling process removes material to define the channel, including the restrictor. Unfortunately, such machining is expensive and time consuming.

A shaft mounting device according to the present invention provides oil flow regulation which is easily tunable, but which is available at a lower cost than prior art lubricant regulation devices.

SUMMARY OF THE INVENTION

A shaft mounting device for an internal combustion engine includes a bearing body having a mounting base for engaging an engine structure. A semi-circular bore is formed in the bearing body. The semi-circular bore extends upwardly from the mounting base. A lubricant inlet port extends upwardly from the mounting base and communicates with a lubricant distribution channel extending about the circumference of the semi-circular bore. An integral flow regulator is located in the lubricant distribution channel downstream from the lubricant inlet port. The flow regulator preferably comprises a formed-in-place hydraulic obstruction extending partially into the lubricant distribution channel from a base portion of the channel. The hydraulic obstruction is integral with the bearing body.

According to an embodiment of the present invention, the present inventive bearing body may advantageously be formed from a sintered metal powder. Alternatively, the bearing body may be formed from die cast metal, or other types of metallic or non-metallic composite materials known to those skilled in the art and suggested by its disclosure.

The present shaft mounting device may be employed to secure a crankshaft within an engine, or a camshaft, or other type of rotating or sliding shafts requiring lubrication furnished through a cap-type of mounting device.

According to another aspect of the present invention, a cylinder head for an internal combustion engine includes a cylinder head casting with at least one camshaft retained upon the cylinder head casting. The camshaft has a lubricant supply passage. At least one camshaft retainer having a cap-shaped bearing body, with a mounting base for engaging the cylinder head casting, is mounted on the casting so as to secure the camshaft. The cap-shaped bearing body has a semi-circular bore formed in the bearing body which cooperates with the mating semi-circular bore formed in the cylinder head casting to define a bearing surface for encircling a portion of the camshaft. A lubricant inlet port extends upwardly from the mounting base and receives lubricant from a mating passage within the cylinder head.

It is an advantage of a shaft mounting device according to the present invention that lubricant flow may be carefully controlled, with minimal risk of losing flow due to plugging of a flow restrictor.

It is a further advantage of a shaft mounting device according to the present invention that the flow restriction incorporated integrally in the bearing body of the shaft mounting device may be easily adjusted to change the amount of flow reaching bearings downstream from the restrictor.

It is a further advantage of the present shaft mounting device that the integral restrictor is less costly than prior art restrictors, because the hydraulic obstruction may be formed during the casting portion of a manufacturing process for the shaft mounting device, which is particularly facilitated in the case in which the bearing body is formed from either cast metal or sintered powder metal.

Other advantages, as well as features and objects of the present invention, will become apparent to the reader of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an engine cylinder head including a shaft mounting device according to the present invention.

FIG. 2 is an elevational view of a portion of the cylinder head shown in FIG. 1, taken along the line 2-2 of FIG. 1.

FIG. 3 is a section view taken along the line 3-3 of FIG. 2.

FIG. 4 is a perspective view of the present shaft mounting device, in this case a camshaft cap, showing the underside of cap 22.

FIG. 5 illustrates a prior art camshaft cap.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIG. 1, cylinder head 10 has camshaft 14, which is maintained in contact with cylinder head 10 by means of a plurality of inventive shaft mounting devices, which are embodied as camshaft caps 22. As fully described below, oil needed for the operation of camshaft 14 is presented to mounting devices 22 by means of lubricant supply passages formed in cylinder head 10.

FIGS. 2 and 3 show a lubricant supply passage, 54, which is formed in cylinder head 10. Lubrication flowing up through passage 54 enters lubricant inlet port 58, which is formed in camshaft cap 22. It is noted that cap 22 has a mounting base, 30, which allows cap 22 to be securely attached to cylinder head 10 by means of screws 38. Cap 22 has a cap-shaped bearing body, 26, with a semi-circular bore, 50, formed therein. Bore 50 cooperates with bore 52 formed in cylinder head 10 to define a bearing surface for encircling a portion of camshaft 14. The portion of camshaft 14 which is encircled by camshaft retainer 22 includes two radially extending bores 46, which allow oil introduced to shaft mounting device 22 from lubricant supply passage 54 to eventually enter camshaft 14, and then to proceed along the length of longitudinal bore 42 (FIG. 3) which is formed in camshaft 14.

The elegance and simplicity of the present invention are fully displayed in FIG. 2, wherein hydraulic obstruction 66 is illustrated. Because the entirety of shaft mounting device 22, including hydraulic obstruction 66, as well as lubricant distribution channel 62, are formed in place during casting or sintering of device 22, the risks and expense of machining are eliminated. In that regard, it is well to note that machining risk includes the problem of under-machining passages, which may cause unwanted flow restriction.

In essence, hydraulic obstruction 66 functions as a weir, or flow regulator, extending partially into the upstream end of lubricant distribution channel 62. Hydraulic obstruction 66 is also shown in FIG. 4. It is easily seen from FIGS. 2 and 4 that the height and length of hydraulic obstruction 66 may be easily decreased during engine development work, so as to tune the flow of lubricant fluid passing from lubricant inlet port 58 to lubricant distribution channel 62. Note also that the adjustment of the size of hydraulic obstruction 66 during engine development may be accomplished with the use of simple grinding tools; unlike the situation with the prior art restrictor shown in FIG. 5, it is often not necessary to re-machine a separate oil restrictor, which must be then carefully cleaned of chips.

The problems encountered in manufacturing the prior art restrictor of FIG. 5 in large quantities are difficult to understate, given that the drillings required to manufacture the restrictor result in contamination, which, if not carefully removed during the manufacturing process, may cause subsequent damage, if not failure, of the very bearings which lubricant is meant to protect. This issue also arises with prior art bearing caps having machined oil distribution channels. As noted above, this difficulty is not an issue with the present inventive solution, which provides oil restriction in a robust, cost-effective manner.

Those skilled in the art will appreciate in view of this disclosure that the present shaft mounting device could be constructed from diecast metals, or sintered metal powders. Alternatively, various other materials, such as composite metallic and non-metallic materials could be employed.

While particular embodiments of the invention have been shown and described, numerous variations and alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims.

Claims

1. A shaft mounting device for an internal combustion engine, comprising:

a bearing body having a mounting base for engaging an engine structure;

a semi-circular bore formed in said bearing body, with said semi-circular bore extending upwardly from said mounting base;

a lubricant inlet port extending upwardly from said mounting base, and communicating with a lubricant distribution channel extending about the circumference of said semi-circular bore; and

an integral, formed-in-place flow regulator located in said lubricant distribution channel downstream from said lubricant inlet port.

2. A shaft mounting device according to claim 1, wherein said flow regulator comprises a hydraulic obstruction extending partially into said lubricant distribution channel from a base portion of said channel.

3. A shaft mounting device according to claim 2, wherein said hydraulic obstruction is integral with said bearing body.

4. A shaft mounting device according to claim 1, wherein said bearing body is formed from sintered metal powder.

5. A shaft mounting device according to claim 1, wherein said bearing body is adapted to secure a camshaft within an engine.

6. A shaft mounting device according to claim 1, wherein said bearing body is adapted to secure a crankshaft within an engine.

7. A cylinder head for an internal combustion engine, comprising:

a cylinder head casting;

at least one camshaft retained upon said cylinder head casting, with said at least one camshaft having a lubricant supply passage; and

at least one camshaft retainer, comprising: a cap-shaped bearing body having a mounting base for engaging said cylinder head casting; a semi-circular bore formed in said bearing body, with said semi-circular bore cooperating with a mating semi-circular bore formed in said cylinder head casting to define a bearing surface for encircling a portion of said camshaft; a lubricant inlet port extending upwardly from said mounting base, and receiving lubricant from a mating passage within said cylinder head; a lubricant distribution channel extending about the circumference of the semi-circular bore formed in the bearing body, with said lubricant distribution channel communicating with said lubricant inlet port and also with said lubricant supply passage of said camshaft; and a formed-in-place flow regulator located in the lubricant distribution channel downstream from the lubricant inlet port.

8. A cylinder head according to claim 7, wherein said flow regulator comprises a hydraulic obstruction formed integrally with said cap-shaped bearing body, and with said hydraulic obstruction extending partially across a portion of said lubricant distribution channel.

9. A shaft mounting device according to claim 7, wherein said bearing body is formed from sintered metal powder.

10. A camshaft mounting device for an internal combustion engine, comprising:

a bearing cap body having a mounting base for engaging an engine cylinder head;

a semi-circular bore formed in said bearing cap body, with said semi-circular bore extending upwardly from said mounting base;

a lubricant inlet port extending upwardly from said mounting base and communicating with a lubricant distribution channel extending about the circumference of said semi-circular bore; and

a formed-in-place flow regulator located in said lubricant distribution channel downstream from said lubricant inlet port, with said flow regulator comprising a hydraulic obstruction extending partially across a portion of said distribution channel.

11. A camshaft mounting device according to claim 10, wherein said bearing cap body and said flow regulator are formed integrally from sintered metal.

12. A camshaft mounting device according to claim 10, wherein said bearing cap body and said flow regulator are formed integrally from metal.

13. A camshaft mounting device according to claim 10, wherein said bearing cap body and said flow regulator are formed integrally from cast metal.

14. A camshaft mounting device according to claim 10, wherein said bearing cap body and said flow regulator are formed integrally from composite material.