US2071051A - Internal combustion engine - Google Patents

Description

1937- c. w; VAN RANST INTERNAL COMBUSTION ENGINE Filed March 30, 1934 H M E N m m 5. w L m m Patented Feb. 16, 1937 INTERNAL COMBUSTION ENGINE Cornelius W. Van Ranst, Detroit, Mich, assignor to Packard Motor Car Company, Detroit, Mich, a corporation of Michigan Application March 30, 1934, Serial No. 718,141

2 Claims.

This invention relates to internal combustion engines and particularly tothe valve operating mechanism thereof. It may be said to more especially relate to hydraulic clearance take-up mechanism such as used in connection with valve operating parts.

The invention may be said to be an improvement upon the mechanism shown in my copending application, Serial No. 667,547, new Patent No. 2,041,983.

Much has been done in recent years in the.

matter of providing hydraulic clearance takeup mechanism for quieting the valve action of internal combustion engines. In most of these the take-up mechanism is applied to the supporting bearing of a rocker arm and the mechanism is supported on a non-rotating or non-oscillating part of the engine. In the present invention the take-up mechanism is mounted on the rocker arm itself and it controls an eccentric bearing member for the roller which bears on the cam shaft. This rocker arm, at the higher speeds of the engine, vibrates very rapidly and it is one of the objects of this invention to so construct the hydraulic means that it will operate properly during these high vibration periods as well as when the engine is rotating more slowly.

More specifically stated, an object of the invention may be said to be to provide the cylinder check valve with means which will prevent itself being vibrated off of its seat during the operation of the device, and to provide the coil spring which operates the plunger in one direction, with means for holding it against lateral vibration.

Another object of the invention is to provide the plunger and cylinder with means for keeping the surfaces clear of dirt or sludge.

Other objects of the invention will appear from the following description taken in connection with the drawing, which forms a part of this specification, and in which:

Fig. 1 is a vertical section through the valve operating parts of an internal combustion engine embodying the invention, and

Fig. 2 is a detail view of the plunger of the device.

Referring to the drawing, II] represents the crank case of an internal combustion engine and II is a fragment of the cylinder casting mounted thereon. I2 is the lower end of one of the valves or one of the push rods, which valve or push rod is to be operated by the mechanism hereinafter described. It is supported in a suitable guide I3 mounted in the crank case or cylinder block, as shown. At the side of the crank case is an opening I5 which is closed by a suitable cover I6 detachably secured to the crank case as by bolts II. The cover I 6 forms a support for the various rocker arms which operate the valves of the. engine and in this cover is a hollow shaft I8 5 which forms the direct pivotal support for the rocker arms referred to. Oil is supplied under pressure from the conventional pump (not shown) to the interior of the shaft I8, as at I9, and the shaft has suitable radial passages 20 for leading the oil to the rocker arms.

The engine cam shaft is indicated at 2| and one of the cams is shown at 22. This cam operates upon a roller 23 which is mounted on suitable roller bearings 24 on a take-up bearing 25, which latter bearing is eccentrically mounted upon a pin 26 on a rocker'arm 21. The rocker arm 21 has its hub 28 pivotally mounted upon the shaft I8, and an oil groove 29 is provided between the hub 28 and said shaft I8, so that the oil fed under pressure from the interior of the shaft I 8 may thus reach the interior of the rocker arm hub 28.

The eccentrically mounted take-up bearing 25, above referred to, has an arm 30 which is adapted to be operated upon by the hydraulic mechanism hereinafter described, for the purpose of controlling the position of the take-up member, in the Well known manner.

From the above description it will be seen that the rotation of the cam shaft 2| will rock the arm 21 on the shaft I8 and thus move the valve or push rod I2. The spring of the latter will return the valve and thus the cam will push the valve open and the spring will close it. When the cam shaft 2I operates rapidly there is, of course, a very rapid vibration of the rocker arm 21 about the axis of the shaft I8. In some instances we are referring to the rocker arm 21 as a vibrating member.

Shown as formed integrally on the rocker arm 2? is a cylinder 3I extending somewhat longitudinally of the rocker arm. In this cylinder is a plunger 32 having a stem 33 extending outwardly therefrom and into contact with the arm 30. A coiled spring 34 closely surrounds the stem 33 and has its outer end secured against a flange or abutment 35 adjacent the outer end of the stem. The inner end of the spring 34 rests against a disk 3% through which the stem 33 passes and which disk in turn rests against the outer end of the cylinder 3|. The disk, therefore, forms an abutment for the inner end of the spring 34 and the opening 31 in the disk 36 is somewhat larger than the stem 33 so that oil may escape therethrough. The flange 36 centers the inner end of the spring.

From this it will be seen that the spring 34 tends to press the plunger outwardly against the arm 30 of the eccentric bearing member 25 but, of course, this spring is not suflicient to overcome the action of the valve spring in returning the valve l2 to its seat.

At the inner end of the cylinder 3| there is a valve member 40 which has a valve seat 4! arranged in a plane substantially radial to the axis of the shaft l8 so that the ball 42 which seats thereon will not be rocked off of its seat by the vibration of the rocker arm 21.

An oil duct 43 leads from the oil groove 29 to a passage 44 in the valve member 40 and to the seat 4| thereof. Thus oil is fed under pressure to the interior of the cylinder 31.

A skeleton washer 45 having openings 46 therein is provided to retain the ball 42 in position adjacent its seat, and the washer 45, which seats against a shoulder 41, and the valve member 40,

are retained in the rocker arm preferably by peening over the extreme outer end of the cylinder as at 48.

It will be understood that the pressure of the oil in the cylinder 3| is sufiicient to retain the ball 42 on its seat (when it is desirable that it should be retained on its seat) against the inertia action of the ball due to the vibration of the rocker arm 21, because this vibration is in the direction of the seating of the ball valve, but difiiculties would arise if the valve seat were arranged in the direction of vibration because then the ball would tend to rock on its seat and there would be back leakage from the cylinder.

There is formed between the contacting surfaces of the plunger and cylinder a leakage or bleed groove 56. As shown, this groove is formed in the cylindrical surface of the plunger and is shown as a spiral groove, thus elongating it considerably. This spiral leakage groove being small in cross section does not interfere with the hydraulic action of the plunger but it does provide a constant leakage and carries off any 'dirt or sludge that might otherwise accumulate in the cylinder; The oil passing from the outer end of th s groove escapes from the cylinder through the opening 31 and lubricates the closely fitting spring 34.

It will be understood that in the operation of the mechanism the plunger 32 will act as a substantially solid abutment as the cam 22 opens the valve, thus preventing the eccentric bearing 25 from appreciably moving on its support, but in case the parts expand so that the valve I2 would otherwise fail to seat, the plunger 32 and the spring 34 will sufiiciently give so that the parts will automatically adjust themselves to the different condition. As the parts cool and clearance tends to be created the plunger 32 will operate on the arm 30 to rotate the eccentric bearing 25 on its support 26 and thus take up the clearance and keep the parts in operating contact so that there will be no noise in the operation of the mechanism.

Although the invention has been described in connection with a specific embodiment, the principles involved are susceptible of numerous other applications which will readily occur to persons skilled in the art. The invention is, therefore, to

of the axis of the bearing of the rocker arm on:

said pivotal support, a plunger in said cylinder and having a stem operating on said take up bearing, said plunger and cylinder having a leakage groove between their contacting surfaceaand a spring supported laterally by said stem and controlling the movement of the plunger in one direction.

2. In an internal combustion engine, thecombination with a pivotal support, of a rocker arm mounted thereon, a take-up bearing supported on said arm, and hydraulic means controlling the position of said take-up bearing, saidmeans comprising a cylinder on the rocker arm, means supplying oil to the cylinder, a check valve means including a valve seat arranged radially of the axis of the bearing on the rocker arm on said pivotal support, a plunger in said cylinder having a stem operating on said take-up bearing, said plunger and cylinder having leakage means between their contacting surfaces, and a spring on,

said stem controlling the movement of the plunger in one direction.

CORNELIUS W. VAN RANST.

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