US2145484A - Hydraulic tappet - Google Patents

Description

Jan. 31, 1939. c1 4E. JHNSON f 2,145,484

HYDRAULIC TAPPET Filed Jan. 25, 1937 2 Sheets-Sheet` l C. E. JOHNSON HYDRAULIC TAPPET Filed Jan. 25, 1957 2 sheets-sheet 2 a proportion Patented `lan. 3l, 1939 .HYDRAC TAPIPIE'E ries E. Jon,

North Muskegon, meh.

Application January 25, 1937, Serial No. 122,234 8 Claims. (Cl. 123-90) This invention relates to self-adjusting valve tappets of the hydraulic type for internal combustion engines. I have heretofore obtained United States Letters Patent No. 2,006,641, dated July 2, 1935, which was reissued as Reissue Patent No. 19,761, on November 19, 1935. I have also pending an application for patent, Ser. No. 104,086 filed October 5, 1936, for Hydraulic tappet, issued August 24, 1937 as Patent No. 2,090,795. In both this issued patent and the pending application means are provided for the quick elimination of air from the oil which is held or trapped in the tappet body and which is put under pressure when the valve is lifted and the valve spring compressed, so that with respect to such trapped body or quantity of oil a rapid elimination of any air therein is attained, thus providing an incompressible liquid body of oil and air which would be more or less compressible, dependent upon the quantity of air contained in the oil.

In the operation of hydraulic valve tappets in internal combustion engines, the oil in most cases lead to the tappets may become wholly or partly filled with air.

Dump, eventually into the chamber of the tappet where the oil is placed under pressure a considerable but which may amount to a few minutes in length. It is Very desirable that the clicking noises, which occur when there is the presence of of air in the trapped oil which isA subject to the pressure of the valve spring, shall not take place for even such length of time as a very few minutes.

One object of my invention is to provide a valve tappet structure wherein there maybe a substantial removal and elimination of air from the oil coming to the valve tappets before it reaches the chamber where it is subjected to the pressure stated. By doing this and then .having the valve tappet further embody the invention rst shown in my reissue patent, No. 19,761, so

as to quickly eliminate such small quantity of air as may be carried to the pressure chamber within the tappet body, a substantially complete and very practical air elimination is secured such that after starting the engine there are no tappet noises.

In my copending application, Ser. No. 104,086 previously noted,

looking in the directions indicated by the arrows.

stem compresses spring 6i the valve stem t is engaged a tappet to which the present invention is directed. The tappet is mounted for vertical movements in a guide block 8. 'I'he tappet, in an internal combustion engine, rests at its lower, end against a cam 9, there being section illustrating thevalve `openings I8 or 28 all in a plurality of such cams on the cam shafty III which is rotated' continuously in the operation of the engine in timed relation to the rotation of the engine crank shaft and to the movements of the engine pistons.'

Withmy invention oil to be supplied to the hydraulic tappets is preferably carried in a horizontal conduit II which runs through the tapv pet guide block 8 in which a plurality of vtappets are mounted. Leads I2 extnd from said conduit laterally to the several tappets. The oil may be carried through a pipe` I3 to the conduit II being under a pressure produced by the. engine oil pump. In the construction of the tappet a cylindrical hollow body I4 is provided having a closed bottom I5, the underside of which rests against a cam 9 with which it is associated. A relatively wide and shallow groove I6 is made aroundthe body I4 at a position and of such a width that when the tappet has been raised to its uppermost position, that is, with the cam 9 havingits high point against the bottom I5 of the body, the lead I2 communicates with the lowermost portion of the groove I6, and in the reciprocations of the tappets such lead I2 is within the limits of the groove I6 at any position that the tappet may occupy. Therefore, there is a continuous supply of oil` to iill the space provided by the groove I6 around the tappet body and between it and the guide 8 in which it moves.

A short distance above the upper limit of the groove I6 a second narrow groove I1 is cut continuously around the body being spaced from the groove I6 by the annular rib shown. An opening I8 is made through the wall of the tappet leading to said groove. Through a wall 'of the guide 8, a passage I9 is made at a location such that when the tappet is raised to its uppermost position (Fig. 2) communication is made between-the groove I1 andthe passage I9. A second opening 20 is made through the wall of the tappet at the upper end of the groove '|6. While one opening I8 and one opening 20 are shown, it is evident that a plurality of such the same horizontal planes may be made, the first openings being in communication with the upper narrow groove I1 and the latter openings in communication with the upper portions of the wide groove I6. Also, in the outside of the tappet body a narrow verticalgroove EI is cut joining at its lower end with an opening 22 made through the wall of the body as shown in Fig. 2, and extending to the top of the tappet.

`A horizontal inwardly extending annular ledge 23 is provided integral with the tappet body I4 above which a valve carrying plug 24 is located.

This plug in outer form is ofl substantially spool shape, having a continuous annular flange v25 at each end, the diameter of these flanges being such that the plug is receivedwith a press flt in the body I4, thereby providing a continuous annular chamber between the walls of the body I4, the extending flanges 25 and the central or body portion of the plug 24. A transverse passage 26 is drilled or otherwise provided through the plug 24 immediately above the upper side of the lowerange 25. A central vertical passage 21 connects at its lower end with the horizontal passage 26 and *at its upper end with a valve chamber which is made as a downwardly extending cylindrical opening in the upper end of the plug 24. A fiat metal plate valve 28 is seated in the lower part of the valve chamber .tappet body and -so that the lower end of against the upper i over the', upper e d of-the vertical passage 21, against which a relatively light coiled spring 29 bears at its lower end. 'I'he up`per end of the spring 29 surrounds a downwardly projecting boss made on the lower end of a reduced portion 30 of a piston 3I which is slidably received in the upper part of the tappet .body I4. A split ring 32 surrounds the smaller diameter portion 30 of the piston and is of a size such that itA bears snugly against the walls of the there is a space between its inner curved side and the part 30 of the piston. At its upper end it is pressed against the shoulder provided between the larger and smaller parts 3l and 30 of the piston, being held thereagainst by a relatively heavy coiled spring 33, the upper end of which bears against the lower end of thev split ring 32 and the lower end against ,the upper flange 25 of the plug 24. The split ring 32 has a small continuous groove 34 around it at its outer curved side and near its upper end,v (connected by a hole with the space between the ring and piston 30) and in a position'such that when the piston is forced down the part 38 strikes ange 25 said groove will be in communication with the opening 22 previously described. The piston is of a hollow construction for. purposes of reducing weight, is integrally closed at its lower end and has its open upper end closed by a cap 35 having a vertical projection which comes against the lower end of the valve stem 4. A split spring wire snap ring 36 seats in a groove near the upper end and at the inner side of the tappet body I4 for releasably preventing the outward movement of the piston beyond a predetermined position.

With this construction, the chamber which is above the valve 28 and which is below and around the reduced end portion 30 of the piston will be filled with oil.. In case air should enter this chamber and be mixed with the oil, air being compressible, the force of the valve spring 6 transmitted to the piston 3I may cause the same to move downwardly so that the lower endof the piston part 30 abuts against the upper end of the plug 24. The air in oil, being lighter than the oil, tends to move upwardly and will pass through` the hole leading through the ring 32 into the groove 34, and when the groove comes into conjunction with the opening 22 in the tappet body such air will pass outwardly through said opening and escape through the groove 2l. After the reciprocation of the tappet has occurred a few times the oil which is trapped in said chamber above the valve 28 will be free of air.

The air which comes inwith the oil into the annular chamber around the central body of the plug 24 and between the upper and lower flanges 25 likewise will tend to separate by rising in said chamber and pass outwardly through the opening or openings I8 to the groove I1 and thence out through the passage I9 at the time that the tappet body reaches its uppermost position as shown in Fig. 2. The oil, passing to the chamber above valve 28, has to enter through the passage at 26, and there will be very little likelihood that any quantity of air will reach such passage because the air will, as previously stated, tend to separate and move upwardly and be eliminated from the tappet by passage outwardly through the opening or openings I8, groove I1 and passage I9.

It will further be apparent that when the engine is at rest, and should oil in the groove I6, the lead 7 I2, conduit Il and pipe Il run back either in whole or part, nevertheless the upper level of the oil around the central portion oi the plug 24 will not be lowered below the opening 28. Therefore, for resupplying oil to thechamber above valve 28 for that which escapes by seepage or to take the place of air which may be eliminated and pass outwardly throughthe passage at 2|. there will be an amply sumcient body of air-free oil for this purpose during the ilrst part of the engine operation after it has been restarted. Further, such body of oil below theopenings 20 tirely consumed before other oil has been pumped thereinto irrespective of how much 'the oil may be drained back'out of the pipe I3, conduit II,

leads l2 and the groove I6, when 'the engine is at rest. Accordingly, with a tappet made of the construction described, there will be little possibility of air ever reaching the chamber above the valve 28.

In Fig. 7, horizontal and vertical passages 31 and 38, joining each other oi the horizontal passage connecting withthe upper end of the groove I6 when the tappet body is in uppermost position, are provided for the initial escape of air before it goes past the valve 28. The plug 39 isof the same type and character shown in the copending application, Ser. No. 104,086. In such structure there is no light spring similar to the spring 29 in Fig. 2 between thelower end of the piston and the valve 88 to hold the valve against too great an upward movement, but a` plate 48 is laid upon the plug 88 between the plug and the spring 33, said plate having a central opening with downwardly extending fingers which prevent too great an upward movement of the valve 28. In this construction the initial separation of air from the oil is not quite so eiTective as it is in the construction shown in Fig. 2; nevertheless there is a relatively large initial air elimination before the oil has passed Y to the valve 28.

In Fig. 8 the plug 4I, which takes the place oi the plug 39 in Fig. 'l and the plug 24 in Fig. 2, has a central opening 21a therethrough at the upper end of which the valve 28 is located. A tube 42` having a vertical passage in alinement with the passage 21a extends nearly to the lower end of the tappet body I4. The passage of oil from the conduit II, through the lead I2a and to the groove I6 and thence into the tappet body, is through openings 43 located below the plug 4| so that the tappet body I4 at all times carries a considerable reservoir of oil,` such oil not receding to a level below the lower side of the openings 43 when the engine is stopped. There is a groove Ha around the plug 4I a short distance below its upper side which communicates with a passage 44 through the wall of the at its outer end-connects with'' vertical groove 45 in the body I4, the upper end of which comes just above the upper end of the tappet guide 8 when the tappet has been position. Further, there is a passage 4B leading from the lower side vof the plug body into the groove I'la whereby, when mixed air and oil are conducted into said reservoir for o il, the major portion of air initially separates, rises. passes through the' passage 46 and eventually out through the'groove 45. .The elimination of the air from that part of the oil which is trapped between the valve 28 and the piston is effected in the same manner, through the ,grbove 2|, passage 22 and the groove 34 as it is in the structure shown in Fig. 2.

will not be en- 'ind with the inner end' body ,yhich passage e lifted to its uppermost l 3 In Fig. 9 the structure shown is very much like that illustrated in Fig. 2. The plug 24a, corresponding with the plug 24 in Fig. 2, has the same upper and lower anges 2E, the openings I8 and 20, the groove I 1 and the passage 26 are the same. The valve chamber is considerably enlarged and elongated in a downward direction so that the vertical passage 21 is decreased in length and the valve 28 is located a considerable distance below the level of the oil carried in the reservoir around the central part ofthe plug 24a, and which oil of the openings 28. 'I'he retention of the valve 28 in its lower position in this structure Is through the medium of a split wire spring ring 48 inserted in the elongated recess 41 in the plug 24a, one end of the ring extending vertically downward as at 49 and terminating in a second ring 50 oi smaller diameter and located horizontally a short distance over the valve 28. The elimination and escape of the air issubstantially the same as in Fig. 2, except that the passagefor the outer esl cape of the air initially entered into the tappet body is through the vertical groove 45 communicatlng with the groove l1 instead of the horizontal passage kI9 as shown in Fig. 2.

The middle portion of the spool-like body 24a carries an annular in or flange I, the edges of which are spaced a very short distance from the adjacent inner Wall of the tappet body I4, in practice approximately s of aninch. This permits the oil, which enters through the openings 28 to iiow downwardly and go to the passage 26. but will tend to obstruct any large bubbles of air moving in a downwardly direction, thereby additionally safeguarding against any excess amount of air coming to and passing by the valve 24.

In Fig. the plug 4ta is similar to that shown at 4I in Fig. 8. The passages 43 for oil entrance below the plug are the same as in Fig. 8. The

plug has a central relativelyl long downward extension to which a shorter tube 42a. is secured, and with this structure the chamber in which the valve is located is of greater length and extends downwardly to a lower position so that the valve 28 is positioned lower than in Fig. 8 and below the horizontal plane of the oil entrance openings 43. The same valve retaining member, having the parts 48, 49 is used herein. The escape of air from the reservoir of oil is through the passage 46, groove lla and groove 45 as in Fig. 8.

The constructions vof valve tappets described are all of particular utility in perfecting air `elimination andy escape from the oil which is used in the hydraulic, automatic adjustment of the tappets with relation to the valve stems 4 with which theyare associated. The presence of air in the oil has been' a very detrimental factor in conjunction with hydraulic valve tappet adjustment. That such air may work out eventually in hydraulic tappets'is not the answer to the .problem as in a practical tappet of this type, and one that manufacturers will adopt and with which themotor using public will be satisfied, the air should be eliminated very quickly so as to avoid the very undesirable clicking and other knocking noises present in tappets when there is air mixed with the oil. As previously stated my early patent eliminated air in one part of the tappet very satisfactorily and improved hydraulic tappets to that extent. The present invenytion eliminates the air which is substantially inevitable as coming with the oil to one or more and 54, that is shown in Fig. 9,.

level does not normally get below the lower side I vsaid oil admission being near but of the tappets when an engine is started after it has had a period of rest and wherein the oil` pumped by the engine oil pump has run back, leaving the oil carrying conduits and passages either wholly or partly lled with air.

Furthermore, with this invention the tappet structure is one which lends itself admirably to large quantity production methods of manufacture for the building of tappets at low cost. All of the parts are easily machined and very quickly assembled at a minimum of cost for devices of this character.

The invention is deiined in the appended claims and is to be considered comprehensive of all forms of structure coming within their scope.

I claim:

1. A valve tappet of -the class described comprising, a lhollow cylindrical tappet body closed at its lower end and having an inwardly extend- 'n ing stop within the same above its lower end, a

plug of substantially spool-like form with a central portion and an annular flange at each end located within said" body, one ange bearing against said stop, said plu'g from its upper end downwardly having a longitudinal centrally disposed elongated opening therein and below said opening having a passage leading to said opening from a side of the plug, a valve in the bottom of said opening covering said passage, a piston mounted within the tappet body above the plug, said tappet body having an oil passage opening in the wall thereof for passage o f oil into the space enclosed between the plug and the adjacent walls of the tappet body.

2. In combination, a hollow tappet body having a closed lower end, a plug oi spool-like form having a press fit in said body and located between the ends and within the body, said plug having upper and lower anges and also having an oil passage therethrough from a point adjacent the lower flange 'upwardly through the central part of the plug. a valve located within said plug across the oil passage, and meansvr for carrying oil into the tappet body member into the space around said plug and between the upper and lower flanges thereof.

. 3. A hollow tappet body of substantially cylindrical form closed at its lower end, a spool-like plug having a press t into said body between the ends thereof, said plughaving annular iianges one at each end and an intermediate portion of a diameter less than the diameter of said flanges, said intermediate portion being provided with a downwardly extending opening or recess therein and with a vertical passage extending from said recess nearly to the lower ange and with a horizontal passage connected with ksaid vertical passage and located above said lower flange, a valve within said recess closing the upper end of the vertical passage, means' for admitting oil through a wall of a tappet into the annular space around the plug and between the anges thereof, below the upper end of said space, means located above said oil inlet for venting air coming in to said annular space with said oil, said air normally rising above said oil to said air venting means, and a piston above said plug within said tappet body between which .and said valve oil passing above the valve is retained. e

4. A hollow substantially cylindrical valve tappet having a closed lower end, a spool-like plug within the tappet body having an intermediate portion of reduced diameter and a danse at each movements, means end of a larger diameter, both flanges being of a diameter to press iit within the tappet body, there being provided an annular oil receiving chamber around the intermediate portion of the plug and between said flanges, said tappet body having openings through the walls thereof, the first of said openings communicating with the extreme upper portion of said chamber and the other of said openings located a short distance below said rst opening, means for carrying oil into said chamber through the lowermost of said openings, and means for the escape of air from said chamber through the uppermost of said openings, as and for the purposes described.

5. A valve tappet of the' class described comprising, a hollow tappet body member having a closed lower end, a plug having a press ilt located within said body member a distance above the lower end thereof, said plug having an oil passage therethrough, a piston mounted for vertical movements within the body member above saidv through said plug, aguide for-saidl tappet body in which it is mounted for vertical reciprocating for eiecting a separation of air from the oil before the same passes by said valve, between said valve and piston, the separation of air from the oil before it reaches the valve and also from the voil located between the valve and means for separating air from oil located:

piston occurring when the tappet body has been' v lifted toits uppermost position in the tappet guide.

6. A valve tappet of the class described comprising a hollow tappet body having a closed lower end and an annular inwardly extending stop therein, a plug having a central portion and an annular flange at each end located within said body, said plug having a longitudinal openving therein and a passage leading to the bottom of said opening from a side of said plug, a valve in the bottom of said opening covering said passage and a'valve retainer in said opening above the valve whereby a limited upward movement of the valve is permitted.

7. A valve tappet of .the class described coml prising a hollow tappet body having an inwardlyl extending stop therein, a plug having a central portion and an yannular ange at each end and an outwardly extending annular vane between said flanges around, said central portion, said stop supporting one of saidv fianges, a longitu-4 dinal opening in said plug, a passageway leading to said opening from a side of said plug, a valve in the bottom of said opening covering said passage, a piston mounted within said tappet body above thel plug, said tappet body having an oil passage opening in the ,wall thereof for passage lof oil into the space enclosed between the plug and the adjacent walls of the tappet body.

8. A hollow valve, tappet having a. closed lower end, a plug within the tappet body, an annular flange at each end of said plug andan annularl iin extending from the intermediate portion of the plug at a point between .the end iianges thereof, an annular oil receiving chamber around the intermediate portion of the plug and between said anges, said tappet body having upper and lower openings in the walls thereof, and means for carrying oil into said chamber through the lowermost of said openings.

CHARLES E. `JOHNSON. l

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