US2051232A - Valve tappet - Google Patents

Description

C. VOORHIES Aug. 18, 1936.

VALVE TAPPET Filed April 25, 1950 INVENTOR. gab/M ATTO EY Patented Aug. 18, 1936 4 UNITED STATES VALVE 'rarrn'r I Carl Voorhies, Buffalo. N. .Y., assignor, by assignments, to Wilcox Rich Corporation, Detroit, Mich., a corporation oi Michigan Application April as, 1930, ,Serial No. 447,243

' 8 Claims. (01. 123-90) This invention relates to internal combustion engines and particularly tothe poppet valves which are operated by valve tappets riding on cams on a cam shaft.

Heretofore it has been customary to provide va poppet valve which is separated from the end of v the valve stem by a clearance to permit an exfrom seating, especially when the valvestem has become expanded due to the heat from themglue and oftentimes the valves are burned out due to the close adjustment.

Therefore my present invention has for its object to provide a valve operating mechanism which will eliminate the clearance in question and with it any noise produced by the valve tappet striking the valve.

A further object is to provide a column of liquid under pressure between the valve tappet and a plunger slidably supported therein to always maintain the latter in contact with the valve stem, with the result that the noises are eliminated and the quietness of the engine is improved.

The above being among the objects of the present invention, the same consists of certain features of construction and combination of parts to be hereinafter described with reference to the accompanying drawing, and then claimed, having the above and other objects in view.

In the accompanying drawing which illustrates a suitable embodiment of the present invention,

Figure 1 is a fragmentary sectional view of an internal combustion engine, showing the valve in raised position and my invention associated therewith.

Figure 2 is a transverse sectional view taken on the line 2-2 of Figure 1.

Figure 3 is a view similar to Figure 1, showing a modified form of invention.

Figure 4'is an enlarged detail view showing the oil seal between the valve tappet and plunger supported therein.

In the drawing in which like numerals refer to like parts throughout the several views, l indicates the engine casing provided with the usual poppet valve ll having a stem i2 extending downwardly therefrom passing through the valve stem guide I3. The valve stem l2 has'the usual spring support l4 thereon-adjacent to its lower end supporting the customary valve spring ll 5 positioned between the support l4 and a portion of the engine It to 'urge thevalve ll toward its seated position. The cam shaft 16 has a cam I] thereon engaging with a push rod base It secured in'the push rod i9 slidable in the guide 20 1 secured in the usual manner in the engine Hi. The push rod is is bored out at 2i to receive the plunger 22 having a hardened head 23 mounted therein adapted to always engage with the end of. the valve stem l2. A bushing 24 is seated in the bottom of the bore 2| on which is positioned a spring '25 seating against a shoulder 28 on the plunger 22 to constantly urge the hardened head 23 in the plunger 22 against theend'of the valve stem i2. The bushing 24 is preferably cupshaped, the end wall thereof being provided with openings 21 therein to provide a cag'e'for the check valve 28 normally seating on the'pushrod I! to close the port 29 therein for 9' pose to be hereinafter'described. The inner surface of the 26 end wall of bushing 24 serves to limit movement of the check valve 28 away from its valve seat to a slight distance. The lower end of the plunger 22 is spaced from the bushing 24 to provide clearance therebetween and ismaintained in that positi n by liquid, which is preferably oil, forcedinto he chamber through the pipe 30 from the engine oil pump, not'shown. However, in the event that the liquid fails to sustain "theplunger in such spaced relation,-due to such causes as failure of the liquid supply or leakage of liquid by thecheck valve 28, the outer surface of the end wall of bushing 24 serves as a stop for limitinginward movement of the plunger, 22 into the. bore 2i of push rod IS, the bushing 24 also serving at all times to prevent'both the plunger 22 and check valve 28 from-"interfering with the action of each other. Thesuide 20 for the push rod I9 is preferably bored out to provide a chamber 2| extending around a portion of the push rod l9 as is clearly shown in Figure 1, the c'hamberiil communicating with the pipe and the passageway 29 to permit on to be pumped from'the pipe 30 to the chamber within thepush rod ll.

During the operation of the engine, the cam H on the cam shaft l6 willraisethe push rod base it as is shown in Figure 1, thus moving the push rod l9 upwardly and forcing the valve ll to open position against the compression of the spring l5. As the cam l'l rotates, the valve ll will move toward its seated position due to the expansion of the spring I I and the valve stem -|2 will follow downwardly in contact with the head 23 in the plunger 22. The oil pressure in,

the chamber in the push rod It will always force the plunger 22 into contact with the valve sternv l2 and oil pressure will be maintained in the chamber by the check valve 2|.

I preferably position the pipe 30 above the.

check valve 28 so that any leakage of oil out of the chamber in the push rod I 8 will flow into the chamber 3i and be trapped therein and will ""not flow back into the pump through the pipe ll.

This construction has anadvantage because of the fact that when the engine has been at rest for sometime, there is a tendency for the oil to leak out of the chamber in the push rod I! so ring 32 around the lower portion of the plunger 22 against which is seated a metal cup-shaped washer 32 to form an oil seal, these members being held in operative position by means of the spring 2!. I In Figure 3 I have shown the. construction heretofore described to which the same numerals have been applied, excepting that the guide 20 for the push rod II is provided with an oil receptacle 35 whereby the oil is permitted to flow by gravity into the chamber in the push rod ll to maintain the pressure therein in the same manner as previously described.

It is necessary to prevent to the greatest possible degree air or gases from entering the hydraulic ccmpressionchamber 2i in the tappet body for the reason that the inclusion of air therei renders the hydraulic medium compressible in this chamber, therebymaking it impossible to control, as precisely as necessary, the

amount the poppet valve I I is raised from its seat.

a So long as the hydraulic medium admitted to or contained in the compression chamber 2| is in-' compressible, the timing and degree of opening the valves can be closely controlled, This-is essential to efllcient operation. The construction and placement of the oil reservoir ii and the relative position of the valve control passage 2! leading from the compression chamber in-the tappet to the, oil reservoir II and the position of I the oil inlet 30 are therefore very important factors in the control of air and gases included in the oil delivered through the oil line 30 and the prevention of the entry of such air or gases into the compression chamber 2i in the tappet body;

The oil reservoir 3| comprises an annular recess formed in the tappet guide 2| which is stationary. The peripheral surface of the tappet body I! is smooth and unrelieved and slides past this oil reservoir 2 I without disturbing or chuming the oil contained in the reservoir, thereby permitting air or gases carried in through the oil line 30 to collect at the top of the-annular recess SI and remain there until they are worked out upwardly between the exterior surface of the tappet body and the guide. The passage 20 in the tappet body leading from the oil reservoir 31 in the tappet guide to the compression chamber 2| in the tappet body is so positioned and placed that during the entire reciprocation of the tappet it remains substantially below the-upper limits,

of the annular recess or, oil reservoir 3| in. the tappet guide, and therefore never comes into communication with the air or gases collected in the upper portion of the oil reservoir Ii, consequently preventing the induction of such air or gases into the compression chamber in the tappet body. The compression chamber 2| in the tappet body is sealed by the washer a at the upper end and the only communication it may have with the outside of the tappet isthrough the valve control passage 2! which ismaintained out of the region of the collected air and gases in the upper part of the oil reservoir it during the entire reciprocation of the tappet.

The use of tappets constructed in accordance with the present invention serves to eliminate the valve noises and the loss of emcienc'y caused 20 by wear and excessive lost motion and still the tappet. contains its compensating mechanism within itself to operate in an effective manner. 'While I have described certain embodiments of my invention in detail it is to be understood 25 upper end thereof, a spring mounted plunger and 35 sealing means therefor in said chamber'ya single valve controlled passage leading from said chamber to'the outside of said tappet body, a cylindrical guide for said tappet having an annular recess therein forming a stationary oil reservoinand an oil passage leading outwardly from the upper portion of said recess, said tappet body and valve controlled passage leading into the hydraulic.

' line of communication with said tappet hydraulic r. 2. In a hydraulic tappet organization, the combination of a stationary oil reservoir in the tappet guide comprising an elongated annular recess in the inner surface thereof, an-unrelieved tappet body reciprocable in said guide without churning ,the'oil in said reservoir, a sealed compression chamber in said tappet body and a valve controlled passage in said tappet body communi eating said compression chamber only with the lower portion of said oil reservoir, whereby the oil in said reservoir is relatively undisturbed during reciprocation of said tappet body and free from included air in the region ,of communica body, a valve controlled passage leading from said compression chamber to the outside of said tappet body and communicating with said gas separation chamber at points below the upper end of the latter during the entire reciprocatory movement of said tappet body, whereby the upper portion of said gas separation chamber serves as a gas trap at all times out of communication with said valve controlled passage, and means for venting gas from the upper end of said gas separation chamber.

4. In a hydraulic tappet organization, the combination of a tappet guide, a tappet body reciprocable in said guide, an oil settlingand gas sepation chamber arranged exteriorly oi! said tappet body, a compression chamber in said tappet body, a spring mounted plunger in said compression chamber for drawing oil into the latter, a valve controlled passage leading from said compression chamber to the outside of said tappet body and communicating during reciprocation of said tappet body with the lower portion 01' said gas separation chamber but out of communication at all times with the upper portion of the gas separation chamber, whereby the upper portion of said gas separation chamber serves as a gas trap at all times out of line communication with said valve controlled passage, the upper end of said gas separation chamber being vented to atmosphere through the clearance between said tappet body and said tappet guide. v

5. In a reciprocating self-adjusting hydraulic valve operating device of the 'class described, the combination of a valve seat, a free non-return valve for opening and closing said seat under the action of gravity and its own inertia, a plunger reciprocable in said device, and means for limiting the travel of said free valve away from its seat and for limiting inward'movement of said plunger into said device.

6. In a reciprocating hydraulic tappet of the class described, a hollow cylinder, 9. non-return valve controlled fluid port in the'bottom of said 5 cylinder, a ball valve for said port and free to open and close the latter under the action of gravity and its own inertia, and an apertured cage member for limiting the movement of said nonreturn valve relative to said port and'for guarding the non-return valve against interference with said plunger.

7. In a reciprocating hydraulic tappet of the class described, the construction comprising the combination of a cylinder having a fluid port at one end thereof, a plunger reciprocable in said cylinder, a valve in the bottom of said cylinder free to open and close said port under the action of gravity and its own inertia, a valve seat for said valve, and an apertured cage member secured in said cylinder for limiting movement of said valve away from its seat and for guarding said valve from interference with said plunger.

8. In a reciprocating hydraulic tappet of the class described, the construction comprising the 25,

combination of a cylinder having a fluid port at one end thereof, a plunger reciprocable in said cylinder, a ball valve in the bottom of said cylinder free to open and close saidport under the action of gravity and its own inertia, a valve seat for said ball valve, and an inverted cup-shaped and apertured cage member secured in said cylinder for limiting movement of said ball valve away from its seat and for guarding said ball' valve from interference with said plunger.

CARL vooanms.

Images