US2370761A - Valve tappet construction - Google Patents

Description

March 6, 1945 H. E. vooRHlEs VALVE TAPPET CONSTRUCTION Filed June 28, 1943 Y BY Y Wd, v rnv/mers.

Patented Mar. 6, 1945 VALYE TAPPE'I" CONSTRUCTION Harry E. Voorhies, Grosse Pointe Woods, Mich., assign'or to Eaton Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application June 28, 1943, Serial No. 492,503

I Cl. 123-90) 13 Claims.

YThis invention relates to automatic compensating tappets for operating valves of internal combustion engines, and more especially, concerns improvements in the construction and arrangement of compensating mechanismfor tappets of such character.

One object of the present invention is the provision of an improved and simplified construction for such tappets and specically to provide a separate cylinder memberA therefor for receiving a reciprocable plunger and associated valving means, which may lbe manufactured separately and applied as aunit to the tappet body. The type of tappet to which this invention relates may comprise a mushroom-shaped device having an enlarged head which contacts the cam. and a tubular body which .-extends therefrom having an inner portion which is arranged to contact with the valve stem; or a so'called barrelshaped body which has a body of uniform diameter and functions in a similar manner. It is usual to provide such a tapfpet with a bore which forms a reservoir or well to contain oil or other hydraulic operating medium, and to t a recip- `rocable plunger' in the upper'end of the bore,

Fig. 1 is a longitudinal crosssectional view of a tappet embodying this invention, shown positioned between a valve stem and cam; and,

Figs. 2, 3, 4, 5, and 6 are views generally similaito, Fig. 1 of the separate cylinder removed from the tappet body, but illustrating other modified forms of tappets constructed according to the principles of this invention.

Now having reference to drawing, particularly to Fig. 1, the end of the stem of a conventional poppet valve is designated I and which is urged body 8. The body v8 has a stepped hollow bore.

A construction such as ydescribed is more fully illustrated in the Voorhies Patent No. 2,074,034,

issued March 16, 1937, for Tappet construction.

The present invention proposes to advance the state of this art further by elimination of the substantially blind plunger pocket in the separate cylinder. Accordingly, to this end. the separate cylinder unit of the self-compensating mechansm which is inserted inthe tappet body is made of two or more pieces for simplication of manufacture, and this has resulted in improved operating and inspection' characteristics.

Further and other objects of the present in- I venticn reside in the novel combination and arrangement of parts about to be described, when are more particularly pointed out in the append! ed claims.

In the drawing like reference characters denote corresponding parts in the several views, and in' which:

which provides a seat for the hydraulic compensatingr mechanism, to be described, and a lower closed end which servesras a reservoir for operating liquid which is supplied through the side .of the guide 4 by a pipe means I0 connected with the usual lubricating system of the engine. Access to the reservoir 9 of the tappet body 8 from the pipe II) is elected by means of a circumferential groove II and a hole I2 thereinto.

Inserted in the enlarged portion of the bore 8, en the step or seat I 3y is an apertured valve` retaining or valve seat member I5 which seats and substantially seals a separate open-ended cylinder I6. For effecting a more complete seal of the juncture of the separate cylinder'lIS and the valve-retaining member I5 a yieldable sealing means I1 may be used. The sealv I1 is preferably Neoprene or other rubber-like material i which is radially and axially acted upon by pres sure of the operating fluid trapped in the compression chamber and is flowabl under the influence thereof to provide .a fluid-tight seal, although it may be a metallic material such as lead or babbit which would be likewise aiTected. Various sealing means modications'are shown in subsequent views, to be described, wherein the seal may have an additional function to provide a combination seal and a portion of the valve seating surface. y Slidably extended from the lower apertured end of the valve retaining member is a hollow tubular element I8 having, in this instance, a poppet valve portion I9 integrally formed on the upper end thereof arranged to be angularly seated on a complementary portion of the valve retaining member, and which, when the members I5, I8 are seated in the bore of the tappet body 8, extends below the oil inlet aperture I2 and well down into the oil reservoir 9 in `mined by operating characteristics.

Positioned in the separate open ended cylinder sleeve I6 is a piston plunger 2l which-at its upper end contacts the end of the valve stem I. In the case of an overhead valve engine it may Contact the push rod, or other selected part of the operating mechanism of the valve train. Extended between the upper end of the plunger 2l and the separate cylinder I6 is a plunger spring 22 which biases the plunger outwardly of the cylinder and keeps it from settling on the head of the valve element I9. However, in the event of complete loss of operating liquid, the plunger 2| may reach the bottom of the separate cylinder and rest on the valve head I9 with some lift loss in the valve stem I, and attendant noise, but still sufficient to enable operation of the engine.

Operation of the device will be very brief inasmuch as itis believed well known in this art from the prior patent cited and wide usage heretofore. Suillce it to say, rotation of the cam moves the tappet body and the compensating mechanism therein upwardly and upon reaching the base circle of the cam, in downward movement, during the dwell portion thereof, the' plunger spring 22 is momentarily freed of the valve gear load to move the plunger 2l outwardly and induct a charge of oil upwardly from the reservoir through hollow tubular valve element I8 and around valve portion I9 into the space below the plunger where the oil is trapped by the valve seating immediately thereafter, as the load of the valve gear is picked up by upward movement ci' the tappet body under the cam action. The o il being incompressible the valve gear thus rides on a solid hydraulic column to maintain a noiseless zero clearance contact with the valve stem I. Provision for expansion of the length of the valve gear parts under normal operating temperatures is accommodated by predetermined fluid escapement upward around the sides of the plunger by a selective fit with itscylinder I6, and the oil so eliminated will be replaced as the cycle of operation is repeated, all as previously described in the aforementioned patent.

Difficulty has been experienced in honing the bore of the separate cylinder I8, such as found in the mentioned Voorhies patent, with suiiicient accuracy in production machining, due to its blind bore. As previously stated the fit of the plunger 2| in the separate cylinder I6 should be close and accurate to afford a predetermined fluid escapement and not'such as to aord little reduction in the hydraulic column during the pressure interval between the valve stem and the tappet. Also in the previous structures pressing in of the oil suction tube and valve cage assembly if not accurately machined and assembled tended to distort the concentricity of the separate cylinder bore and this inaccuracy was reilected in.the t of the plunger when inserted therein.

In the present application these difliculties have been avoided and the problem solved by provision of the separate open ended cylinder I6 which may be readily formed from stock material and easily and accurately machined inasmuch as a hone may be passed completely through it which thus eliminates the disadvantages heretofore encountered in attempting to hone a blind bore. The valve retaining blank I5 is likewise separately and easily formed and machined and the parts assembled together with a minimum of selective fits. Fluid escapement, if any, from the compression chamber outward between the .luncture of the cylinder and valve retaining member is prevented by the sealing washer I1, aforementioned, or any of the sealing means shown in other figures of the drawing. Although the bottom of the cylinder I6, which comprises the valve retainer I5 in this case, is formed separateV from the cylinder I6 and not permanently secured thereto, as long as no leakage is permitted at the joint between these two parts the structure will operate satisfactorily. This is for the reason that the cylinder I6 will always be held in operative relationship with respect to the retainer I5 through pressure of the spring 22 so that while the retainer l5 may be readily removed from the cylinder I6 upon disassembly as long as the seal I1 seals the joint between them, t between the two is not important. 0n the other hand it will be appreciated, of course, that the retainer I5 may have a light press t into the cylinder I5 if this is deemed to be of advantage.

In Fig. 2 a very similar construction is shown in which a modified sealing washer IIa is inserted in a peripheral groove of the valve retaining element l5a for positive sealing of the juncture thereof with the separate cylinder I6. In this instance the poppet valve portion I9, of the tubular element I8, is also an angular valve seating surface cooperating with a complementary portion of the valve retaining element. Otherwise all the features, attendant advantages and operating principles of the previous construction are embodied inthis modiiied structure.

In Fig.- 3 another modification is shown also very similar to the rst construction, but in this instance the sealing washer I'I previously described has been replaced by a washer element I'Ib which provides a combination sealing means for the juncture of the separate cylinder I5 with valve retaining element i512, and also a portion of the seating surface of the valve element I9a therewith,` that is flat-seated as distinguished from angular seat I9.

Another modification' shown in Fig. 3 and which grooved to form an axially disposed shoulder 23- upon which seats the lower end of a cone type of coil spring 24, the spring 24 being normally held under a light tension between the seat 23 and the bottom of the valve retaining element I5b. This form of construction not only serves the same purpose as the snap ring 20 in limiting upward movement of the valve Isa but further aids in increasing the speed of action of the valve and for this reason it may adapt itself for use in tappets employed on higher speed enginestban the type of construction shown in the remaining views. Otherwise this construction functions in the same manner and with the attendant advantages of the device in Fis. 1.

In Figs. 4 and 5 the location of further modied sealing washers I'lc and Hd, respectively, together with their respective valve portions I9b and ISc, havebeen varied as shown to illustrate optional constructions that may be employed. In these instances the sealing washer is either imbedded in the seating surface of the valve as by being received in an annular groove as shown in `the case of the valve portion I9b in Fig". 4, or

carried thereby' in a peripheral groove, as shown in the case of the valve portion I9c in Fig. 5, as

- tubular element 18a has a headed portion providin'g a valve seat which is press fitted into the member I c. A balltype check valve 25 is seated thereon and surrounded by a ball cage member 26 which is press tted yinto the valve retaining element I5c to provide a predetermined opening travel for the check valve. In this instance the hollow tubular element is, of course. not slidably mounted as in the -previous instances since the valve means is incorporated in tle movable ball check, on the upper end thereof.

Formal changes may be made in the speciiic embodiments of the invention described without departing from the spirit or substance of the broad invention, the scope of which is commensurate with the following claims.

IWhat I claim' is:

1. A hydraulic valve tappet comprising a tappet l body having a longitudinal bore closed at its lower end and adapted to receive a liquid, an

` apertured valve seat member supported in said bore, a separate open ended cylinder seated upon said valve seat member, a hollow tubular element extended from the lower part 0f tlfe valve seat member into the closed end of the bore, one-way valve means at the upper end of said tubular element adapted to allow liquid to flow upwardly from the closed end of the bore into the cylinder. a plunger slidably mountedin the cylinder and biased outward-ly therefrom, and means for maintaining liquid in the bore.

2, A hydraulic valve tappet comprising a tappet body having a longitudinal bore closed at its lower end and adapted to receive a liquid, an'

apertured valve seat member supported in said bore, a separate open ended cylinder seated upon said valve seat member, -means for sealing the 4means for maintaining liquid in the bore.

3. A hydraulic valve tappet comprising a tappet body having a longitudinal bore closed at its lower end and adapted to receive a liquid, an apertured valve seat member supported in said bore, a separate open ended cylinder disposed within said bore and seated upon said valve seat member, a

hollow tubular element extended from the lower part of the valve seat member into the' closed end of the` bore and including a one-way valve means on the upper end thereof adapted to allow liquid to ow upwardly from the closed end of theebore into the cylinder, combination means for sealing the juncture of the separate cylinder with the valve seat member and also for partially seating the one-way valve means thereof, a. plunger slidably mounted in the cylinder and biased outwardly therefrom, and means for maintaining liquid in the bore.

4. Aliydraulic valve tappet comprising a tappet body havinga longitudinal -bore closed at its lower -endand adapted to receive a liquid, a separate open ended cylinder disposed in said bore, an apertured valve` seat member supported in said bore and seating the lower end of the separatecylinder, a hollow tubular element slidably received by said valve seat member and extended from the lower part of the valve seat member into the closed end of the bore and including a one-way valve means on the upper end thereof adapted to allow liquid to flow upwardly from the closed end of the bore into the cylinder, means for limiting said sliding movement of the oneway valve means relative to said valve seat member, a plunger slidably mounted in the cylinder and` biased outwardly therefrom, and means for maintaining liquid in the bore.

5. A hydraulic valve tappet comprising a tappet body having a longitudinal bore closed at its lower end and adapted to receive a liquid, a separate open ended cylinder disposed in said bore, an apertured valve seat member supported in said bore and seating the lower end of the separate cylinder', a hollow tubular element slidably received by` said valve seatmember and extended from the lower part of the valve seat member into the closed end of the bore and including a oneway valve means on the upper end thereof adapt ed to allow liquid to flow upwardly from the closed end of the bore into the cylinder, means for limiting said sliding movement of the one-way valve means relative to said valve seat member, combination means for sealing the juncture of the y separate cylinder with the valve retaining member and also for seating the one-way valve means thereof, -a plunger slidably mounted in the cylinder and biased outwardly therefrom, a'nd means for maintaining liquid in the bore.

6. A hydraulic valve tappet comprising a tappet body having a longitudinal bore closed at its lower end and adapted to'receive a liquid, a separate open ended cylinder disposed in said bore, an apertured valve retaining member supportedv in said bore and seating the lower end of the separate cylinder, a hollow tubular element slidably received by said valve retaining member and extended from the lower part of the valve retaining member into the closed end of the bore and including a one-way valve means on the upper end thereof adapted to allow liquid to ow upwardly from the closed end of the bore into the cylinder, snap ring means extended around the tubular ele.. ment and'arranged to abut against the lower end of the valve retaining member for limiting movement of the one way valve means of the tubular element to a predetermined amount, a plunger slidably mounted in the cylinder and biased outwardly therefrom, and means for maintaining liquid in the bore.

7. A hydraulic valve tappet comprising a tappet body having a longitudinal bore closed at its lower end and adapted to receive a liquid, a separate open ended cylinder disposed in said bore. an

apertured valve retaining member supported in said bore and seating the lower end of the separate cylinder, a. hollow tubular element slidably end thereof adapted to allow liquid to ow upwardly from the closed end of the bore into the cylinder, spring means constantly urging said valve means toward seated position, a plunger slldably mounted in the cylinder and biased outwardly therefrom, and means for maintaining liquid in the bore.

8. A hydraulic valve tappet comprising a tappet body having a longitudinal bore closed at its lower end and adapted to receive a liquid, a separate open ended cylinder disposed in said bore, an apertured valve retaining member supported in said bore and seating the lower end of the separate cylinder, a hollow tubular element slidably received by said valve retaining member and extended irom the lower part of the valve retaining member into the closed end of the bore and including a poppet valve means on the upper end thereof adapted to allow liquid to iow upwardly from the closed end of the bore into the cylinder, means for limiting movement of the poippet valve means of the tubular element, seating means for said poppet valve on the valve retaining member, a plunger sl'idably mounted in the cylinder and biased outwardly therefrom, and means for maintaining liquid in the bore.

9. A hydraulic valve tappet comprising a tappet body having a longitudinal bore closed at its lower end and adapted to receive a liquid, a separate open ended cylinder disposed in said bore, an apertured valve retaining member supported in said bore and seating the lower end of the separate cylinder, a hollow tubular element slidably received by said valve retaining member and extended from the lower part of the valve retaining member into the closed end of the bore and including a poppet valve means on the upper endl thereof adapted to allow liquid to flow upwardly from the closed end of the bore into the cylinder,

means for limiting movement of the poppet valve means relative to said valve retaining member, seating means for said poppet valve on the valve retaining member, combination means for sealing the juncture of the separate cylinder with the valve retaining member and also for partially sealing the poppet valve means thereof, a plunger slidably mounted in the cylinder and biased outwardly therefrom, and means for maintaining liquid in the bore.

10. A hydraulic valve tappet comprising a tappet body having a longitudinal bore closed at its lower end and adapted to receive a liquid, a separate open ended cylinder disposed in said bore, an apertured valve retaining member supported in said bore and seating the lower end of the separate cylinder, a hollow tubular element slidably received by said valve retaining member and extended from the lower part o! the valve retaining member into the closed end of the bore and including a poppet valve means on the upper end thereof adapted to allow liquid to flow upwardly from the closed end of the bore into the cylinder,

means for limiting movement of the pppet valvev means relative to said valve retaining member, seating means for said-poppet valve on the valve retaining member, yieldable means imbedded in a seating surface of the poppet valve for sealing the same to said valve retaining member when in avclosed position, a plunger slidably mounted in the cylinder and biased outwardly therefrom, and means for maintaining liquid in the bore.

ll. A hydraulic valve tappet comprising a tappet body having a longitudinal bore closed at its lower end and adapted to receive a liquid, a separate open ended cylinder disposed in said bore, an apertured valvev retaining member supported in said bore and seating the lower end of the separate cylinder, a hollow tubular element slidably received by said valve retaining member and extended from the lower part of the valve retaining member into the closed end of the bore and including a poppet valve means on the upper end thereof adapted to allow liquid to ow upwardly from the 4closed end of the bore into the cylinder, means for limiting movement of the puppet valve means of the tubular element, seating means for said poppet valve on the valve retaining member,

yieldable means carried by a seating surface of the poppet Valve for sealing the same to said valve retaining member when in a closed position, a plunger slidably mounted in the cylinder and biased outwardly therefrom, and means for maintaining liquid in the bore. Y

12. A hydraulic valve tappet comprising a tappet body having a longitudinal bore closed at its lower end and adapted to receive a liquid, a separate open ended cylinder disposed in said bore, an apertured valve retaining member supported in said bore and seating the lower end of the separate cylinder, a hollow tubular element slidably received by said valve retaining member and extended from the lower part of the valve retaining member into the closed end of the bore and including a poppet valve means on the upper end thereof adapted to allow liquid to flow upwardly from the closed end of the bore into the cylinder, means for limiting movement of the poppet valve means'of the tubular element to a predetermined amount, seating means for said poppet valve on the valve retaining member, means supported by the valve retaining member providing a' combination yieldable seal with the poppet valve and also the juncture with the separate cylinder, a plunger slidably mounted in the cylinder and biased outwardly therefrom, and means for maintaining liquid in the bore.

13. A hydraulic valve tappei; comprising a tappet body having a longitudinal bore closed at its lower end and adapted to receive a liquid, a separate cylinder disposed in said bore, a hollow tubular element slidably mounted relative to said cylinder extended from the lower part of the cylinder into the bore and including a. one-way valve means o the upper end thereof adapted to allow liquid to flow upwardly from the lower part of the bore into the cylinder, means for limiting opening movement of the one-way valve means of the tubular element to apredetermined amount, a.

HARRY E. VOQRHIES.

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