DE1815994A1 - Hydraulic valve lifter - Google Patents

Description

Patent attorney

Dlpl.-inn. Ka-iWassel

8 Μϋησιβη 1o
Hohenstauienstr. 2, phone 33811! 8 Munich I3, the "« Π

FK-2371

Ford-Werke, Aktiengesellschaft 5 Köln-Deutz 1
Ottoplatz 2

"Hydraulic valve lifter"

For this registration, the priority of registration Ser. N. 699 251 dated January 19, 1968 in the United States claimed by North America.

Brief description

The invention is concerned with the design of a hydraulic valve tappet for internal combustion engines. The valve tappet according to the invention is provided with a two-way check valve which, due to its inertia, acts in the critical speed range of the machine to effectively seal off the torque-transmitting fluid chamber between the tappet - a cylinder and the piston to prevent the pressure oil from flowing into the cylinder or from emptying it below the fluttering speed of the valves.

Main description

The invention is essentially concerned with a hydraulic one Valve tappet, you are concerned in particular with such an embodiment of a valve tappet that has both a The pressure oil continues to flow into the ram cylinder as well

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Prevents it from being emptied in the critical speed range of the machine, thereby reducing the machine's maximum speed to increase.

Many of the hydraulic lifters that are used today for the valves of internal combustion engines usually have a one-way check valve. These hydraulic valve lifters consist of an outer one Plunger cylinder and a piston movable in it, these two parts being separated from one another by a liquid are separated that are used to transmit the back and forth. forward movement of the plunger cylinder to and from the piston is used via a valve stem on the intake and exhaust valves. The check valve sits during the Valve actuation, whereby the liquid is pressurized, and rises when the valve is idle from its seat in order to thereby enter the chamber of equalizing fluid to let flow. For an embodiment of this type, however, it should be noted that in some areas it is higher Machine speeds the valve closing spring a phenomenon which could be referred to as spring jump and which occurs when the valves reach their critical speeds achieve, in which the natural oscillation of the spring is a low-order harmonic oscillation of the The vibration under which the valves operate. This condition reduces the effective force of the spring and enables a momentary separation of the valves. This causes the non-return valve to lift off from its stationary position Seat and flow of the liquid into the chamber to an extent that thereby the plunger assembly becomes an extension learns. This ultimately leads to a continuous lifting of the valves from their seats and thus to a loss of drive energy and an inability of the machine to develop a higher drive energy beyond this range,

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BATH ORIGINAL

In order to correct this disadvantage of conventional hydraulic valve lifters, attempts have been made to compress the lifters at critical speeds by an overhead ball check valve, as suggested in US Pat. No. 2,902,015. In the high speed ranges of the machine in which the spring jump occurs, the inertia of the overhead ball valve will lift it from its seat and thereby allow part of the high pressure fluid to flow back out of the chamber into the supply line. Thereby, the piston is moved to the tappet base down, that is, the plunger is thereby compressed and allows over the conventional plunger higher speeds λ schwindigkeitsbetrieb before the flutter speed (toss speed) of the valves occurs.

The aforementioned type of compressible valve lifters however, it has the disadvantage that it is very noisy because of the compression of the tappets on the valves greatly increased play or kickback occurs.

The invention is concerned with the Ausfülirungsform a hydraulic valve tappet j which combines the advantages of the two aforementioned embodiments. According to the invention therefore an embodiment, there is provided in the critical speed range of the engine, neither a subsequent flow (k of the fluid in the plunger cylinder, yet compressing the plunger allows wodux-ch of the speed range up to the point increases, on which mostly with "flutter speed" Is referred to.

The invention achieves the foregoing either through the use of a single check valve that alternates seated against one or the other of two channels which allow the flow of liquid into the liquid chamber

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BATH ORIGINAL

of the plunger and out of this control, or by two check valves, which are similar with a single channel cooperate. Below the critical speed of the Valves, the valve-passage combinations transmit the upward thrust of the cam to the intake or exhaust valve to open, with the non-return valve to block the flow of liquid out of the chamber, apart of a predetermined, controlled leakage amount. The check valve, on the other hand, is lifted during the rest pause of the Valve from its seat to allow liquid to flow into the chamber and so that the liquid on its to raise the original height. In the critical speeds of the valves, during which excessive jumping the valve springs occurs, the valve mass is chosen so that its inertia acts in one direction, in * which regardless of whether or not the plunger assembly accelerates or decelerates, a fluid flow into the chamber to block in or out of this. In this way the liquid chamber does not lose high pressure liquid, what a compression of the plunger could cause, no liquid can penetrate into the chamber, which would cause the plunger to inflate.

From the above it can be seen that a feature of the invention is to be seen in that the hydraulic valve tappet according to the invention below the conveying speed of the valves is neither inflated nor compressed. Another one The feature is to be seen in the provision of check valves, which due to their mass in the critical speed range the masohine act to the high pressure chamber during to keep the valve actuation constantly closed and yet a lifting of the check valve from its seat in the conventional Way to enable fluid in the valve to compensate for leakage losses during the idle period to flow into the chamber.

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BATH ORIGINAL

_ 5 -

In the context of the present invention, a hydraulic Created valve tappet, which consists of an outer tappet cylinder in which a thrust-transmitting, displaceable Piston is fitted very precisely, this fit being chosen so that between these two parts a liquid chamber is formed, to which the liquid flow either through a single, alternating is controlled against two channels seated check valve or by two check valves, which alternately against sit on a single channel or that interact independently of one another with different channels, namely in Depending on the pressure difference between the liquid in the chamber and the liquid acting on the valve the liquid source. The inertia of mass of the non-return valve causes the liquid vents to be sealed off at the critical speeds of the machine valves waive over the entire period of valve actuation of an expected leakage, regardless of whether the ram is accelerated or decelerated.

Further features and advantages of the invention are illustrated in the following description in the drawing preferred export forcnen recognizable. It shows;

Figures 1, 2 and 3 are cross-sections of three embodiments

a hydraulic valve lifter according to the invention, and

Figures 1 a, 2 a and 3 a cross-sections of alternative embodiments of the embodiments according to figures ₉ I 2 and 3. FIG.

In Figo 1 with the reference arrow 10 is a hydraulic valve tappet referred to in its entirety, which is preferably used for the valves of an internal combustion engine. Of the

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BATH

The valve tappet is drawn almost to the scale 1 ι 1 · This valve tappet can also be used for other purposes, where the effects to be described below are desired, without abandoning the idea of the invention. The hydraulic valve tappet 10 comprises an outer, cup-shaped tappet cylinder 12 with a base 14 'which rests on a cam 16 which is normally attached to the camshaft 18 of an internal combustion engine. An overhead, cup-shaped piston 20 is slidably fitted into the cylinder 12, and a plunger bearing 22 is fastened opposite its upper, open end. The tappet ball 24 is provided with a valve lubrication channel 26 which is connected to the cavity 28 of the piston 20 via a channel 27.

The bottom of the piston 20 is provided with an unrestricted channel 30 which allows the liquid between the chamber 28 and a chamber 32 which is formed between the piston head and the cylinder head. The Chamber 28 is a low-pressure fluid chamber and is in communication with a line that carries fluid under pressure brings in, such as pressurized oil under a pressure of about 3 kg / cm, through a plurality of inlet channels 34. These inlet ducts 34 have an annular space 36 upstream between piston and cylinder, and the cylinder is provided with an inlet channel 38.

The flow of the essentially low pressure liquid from the chamber 28 via the channel 30 into the chamber 32 is controlled by a ball check valve kO . This check valve comprises a ball k2, which is biased by a spring kk against the channel opening, the spring kk sits on the bottom of a cup-shaped spring holder k6 . This spring holder 46 is pressed upwards against the bottom of the piston 20 by a spring 48,

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it is provided with a liquid channel 50.

Before the operation of this hydraulic valve tappet is described below, it should be pointed out that the mass of the ball hZ is chosen so that the valve inertia has essentially no effect on their movement below the critical speed of the machine valves. At and above this speed, however, the inertia of the valve mass causes the ball to seat either against channel 30 or against channel 50, depending on the direction of acceleration of cylinder 20 in combination with the fluid pressure difference between chambers 28 and 32, thereby to keep the high pressure chamber 32 closed for the entire period of this speed range, apart from a predetermined amount of fluid leakage from the chamber 32 back into the low pressure system via the minimally small space between the walls of cylinder 12 and piston 20.

In operation, the hydraulic valve tappet is initially filled with oil or another suitable liquid, such as machine oil, via the channel 38, the annulus 36, the chamber 28 and the channels 30 and 50. The cylinder becomes the lower speed range of the machine pushed upwards when the cam 16 leaves its base circle Λ , and this has the consequence, in the known manner, that the spring of the inlet or outlet valve of the machine directly exerts a reaction force via the tappet ball 2h and the bearing 22 on the piston 20 exercises. As a result, the liquid in the chamber 32 is subjected to a higher pressure than the liquid in the chamber 28, as a result of which the ball k2 sits sealingly against the channel 30. Since the liquid or the oil in the chamber 32 is not compressible, the cylinder 12 and piston 20 are essentially

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are moved upwards as a unit. From Chamber 32 however, some leakage of the liquid flows back to the liquid source via the space between the cylinder 12 and the piston 20, as is known from previously known embodiments. This will make it a slight relative movement between piston 20 and cylinder 12 come, the piston 20 moves downwards while the cylinder 12 moves upwards.

If the cam 16 is rotated into a rotational position in which the cylinder base 1 ^ is in contact with the base circle of the cam, then the machine valve has closed and its valve spring then no longer exerts a force on the piston. The amount of leakage has now created a clearance between the valve and the piston, and this game is thereby compensated for by the spring ^ 8 the piston 20 is moved relatively against the cylinder 12 upwardly. As a result, a lower pressure is created in the chamber 32 compared to the chamber 28, whereby the. Sphere h2. is lifted from its seat so that liquid can flow from chamber 28 into chamber 32 and thereby compensate for the amount of leakage.

The above-described effect occurs below the critical speed of the valves. Is this critical speed - for example at 5000 rpm. - reached, then there is excessive jumping of the coil springs. As a result, the reaction force on the piston 20 is increased and weakened intermittently. In the case of a conventional design, this would mean that the valve tappet would be inflated if the reaction force were less than the force of the spring kB, and this in turn would result in constant opening of the engine valve and a consequent limitation in engine performance. The mass inertia of the check valve is now but at this critical speed

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BADOIfJGJNAL

Effective in the valve tappet according to the invention and has the effect that the high-pressure chamber 32 is effectively sealed regardless of the fluttering spring reaction. It should be explained here more precisely that at this critical speed a rapid upward acceleration of the cylinder 12 and the piston 20 causes a reduction in the inertia capacity of the ball hZ, so that it sits against the channel and thereby blocks leakage of the liquid between the chambers 32 and 28 . A sudden reversal of the acceleration of cylinder 12 and piston 20, whereby the reaction force is released on the plunger 20 causes a lifting of the ball k2 from its seat in the channel 50, the ball k2 then sitst against the channel 30, which in turn leakage the liquid between the chambers 32 and 28 is blocked. The sitting of the ball hZ against the channel 50 or against the channel 30 thus prevents a. Squeezing or inflating by moving between the chambers. 28 and 22 an excessive leakage of liquid is prevented is prevented ο By this way, a pumping and compression of the valve lifter "^ the parts in the critical speed range of the engine remain ReIatillage each _other's namely how, at the speeds below this range The result is that the valves do not work noisily or are kept below the flutter speed in the open position. The machine can thus work at higher speeds, the upper limit being the inertia of the motor

The rule is that if they are not too tight against the canals.

Figure 2 shows a modified embodiment. The embodiment voh piston and cylinder essentially correspond the embodiment according to Figure 1, the execution

but forms differ in the use of two that control a single channel, opposite the

* J \ J ^ j u? * j ie UQ (i <d

Use of a single ball valve that has two channels controls. The embodiment according to Figure 2 comprises a double-acting Disk valve 51 with conical valve bodies 52 and 5 ^ · »which are arranged on both sides of a channel 30 and are connected to one another via a shaft 56. The valve body 52 and 5 ^ are axially adjustable with respect to each other, * namely by means of a screw-nut combination 58, in order to avoid the time gaps between sitting on to be able to change the two valve bodies on their seats. It is readily apparent that this valve 5 "! Can of course also be made in one piece can without the possibility of axial adjustment of the two valve bodies and without losing any of the idea of the invention Distance is taken. As FIG. 2 also shows, the poppet valve 51 is spring-loaded 60 biased against the lower part of the channel 30. In terms of its effect, this hydraulic one differs Valve tappet not from the valve tappet according to Figure 1. The valve 51 sits alternately against each other Opposite openings of the channel 30, thereby both an inflation and a compression of the plunger in the critical speed range of the machine valves. Again is the mass of the double acting Poppet valve 5I chosen so that the mass inertia of the valve is ineffective below the critical speed of the machine.

FIG. 3 shows a further embodiment whose effect essentially corresponds to the effect of the embodiments according to FIGS. 1 and 2. For this embodiment, two ball check valves are provided instead of the double-acting poppet valve 5 ″ I according to FIG. 2 and the single ball k2 according to FIG blocked for periods that essentially correspond to the periods in

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6AD

which the ball 42 according to FIG. 1 blocks the channel 30. The opposite opening of the channel 30 is controlled by a ball 62, which is larger and heavier than the ball 61. This ball 62 is pressed against the bottom of a hat-shaped holder 64 by a spring. This spring rests on an intermediate piece 66 which is provided with a channel 68 arranged in alignment with the channel 30. The action of this hydraulic valve lifter corresponds essentially to the action of the valve lifter shown in FIGS. 1 and 2. Raising the cylinder 12 creates a reaction or resistance on the piston 20, whereby the pressure in the chamber 32 is increased to a value which is sufficient to push the ball 61 against the channel '30, thereby allowing the plunger to move uniformly upward. ™ When the cylinder 12 returns to the base circle of the cam 16, the pressure in the chamber 32 is reduced to a value which allows the piston 20 to be pushed up relative to the cylinder 12 by the spring 48, whereby the ball 61 is removed from its seat is lifted off and thereby liquid can flow into the chamber 32 to compensate for the amount of leakage. The ball 62 does not work in this normal speed range which is below the critical range. In this critical speed range, however, there are momentary reductions in the reaction force as a result of the valve springs jumping. Once is reached, therefore, the critical speed and valve is the reaction λ tion force lower than the force of the spring 48, then the pressure difference between the chambers 28 and 32 is reversed. The tension of the spring 48 would normally lift the ball 61 from its seat, thereby allowing the plunger to be inflated. The inertia of the ball 61 now holds the ball 61 against its seat during the downward acceleration. During the decelerated upward movement, the heavier inertia of the ball 62 will now cause it to sit on the channel 30 before the inertia of the ball 61 does

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causes it to stand out from channel 68. This prevents any leakage of liquid from the chamber 32 or any inflow of liquid into it Chamber, causing an inflation or compression of the valve stem is prevented.

FIGS. 1 a, 2 a and 3 a show alternative versions of the embodiments according to FIGS. 1, 2 and 3 Inner and outer cylinders are secured against relative movement by circlips 72 and 7. Between the cylinders there is an annular groove 76 which allows the flow of liquid from a low pressure source to a channel 78. An overhead controlled, cup-shaped piston 20 ', which is provided with a plunger bearing 80. The ball check valve 83 is pretensioned in this case by a spring 8k against the channel 78; The holder is held in position by a compression spring, and in normal operation, a movement of the cylinders 12 'and 70 by the cam 16 directly causes a pressure increase in the Chamber 82, whereby the ball 83 is held against its seat on the channel 78. The liquid in chamber 82 thus transmits the upward movement of the cylinder to the engine valve. If during the further rotation of the cam 16 the cylinder base 1 * M comes into contact with the base circle of the cam, then the pressure in the chamber 82 is reduced to a value that is below the pressure value of the liquid source The seat is lifted, and liquid can flow into the chamber 82 to compensate for the amount of leakage, in a manner similar to that described in connection with FIGS. 1, 2 and 3. In the critical speed range of the machine, the Maasen inertia causes the

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gel 83 their seat either against the channel 78 or against the channel 88 depending on the direction of acceleration of the cylinders 12 'and 70, creating an excessive Leakage of the liquid from the high pressure chamber 82 or an inflow of liquid into this chamber is prevented. Inflation or compression of the valve tappet is also prevented here, as has already been done in connection with the other embodiments became.

The embodiments according to FIGS. 2 a and 3 a are similar in terms of their embodiment and their effect to the embodiment according to FIG. 1 a, with regard to the number and embodiment of the valve bodies they correspond to the embodiments according to FIGS a is the only, double-acting ball 83 according to Figure 1 a replaced by a double-acting, two-part poppet valve 51 'with valve bodies 52 ¹ and 5 ^ ·' »a spring holder 86 'and springs 8 ^' and 90 ¹ , all other parts correspond essentially the parts of the embodiment according to FIG. 1 a. In the embodiment according to FIG. 3a, two independently acting ball check valves with balls 62 'and 61' are provided, which correspond to the two balls 61 and 62 of the embodiment according to FIG. It is assumed that the embodiments according to FIGS. 2 a and 3 a are understandable with regard to their effect from the above description.

From the above it can be seen that the invention provides a hydraulic valve lifter which is not only in the conventional way, but also an inflation or compression of the plunger in the prevents critical working range of the valves at high machine speeds, so that higher machine speeds can be maintained until the valves get their actual flutter speed.

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Claims (1)

Expectations j 1st; Hydraulic ram with an outer, with alternating Frequencies reciprocating cylinder and a tight fit in this, a thrust-transmitting cylinder Pistons which are biased against each other by a spring, with one between the cylinder and the piston via a Channel in which a check valve is arranged, with a pressure source connected to the liquid chamber Transmission of a thrust force is arranged between these "two parts, in particular to compensate for play of the valves of internal combustion engines, characterized in that the check valve (40, 42; 51, 52, 54; 61, 62; 83; 51 ·, 52 ', 54'; 61 ·, 62 ·) such a predetermined one Mass is given that it is below a predetermined oscillation frequency of the cylinder (12; 12 ', 70) in Depending on the pressure difference between the liquid in the chamber (32; 76) and that of the pressure source inflowing liquid is moved between a blocking and a release position, but ch above the predetermined oscillation frequency depending on the acceleration of the cylinder in each the two directions and depending on its inertia assumes a blocking position. 2. A plunger according to claim 1, characterized in that the channel is divided into two spaced apart sub-channels (30, 50} 78, 88) is divided between which the check valve (40, 42; 83) is movable and against which it sits alternately. 3. plunger according to claim 1 and 2, characterized in that the check valve has a ball (42; 83) as a valve 909831/0893 body includes which by a spring {kk; 8k) against which a partial channel (30; 78) is biased. k. Tappet according to claim 1, characterized in that the check valve is designed to be double-acting and comprises two valve bodies (52, 54; 52 ", 5 ^ '5 61, 62; 61', 62") which alternate against the opposing openings of the Channel (30; 30, 68) sit. 5. The plunger according to claim h, characterized in that the check valve has two interconnected poppet valves (52, 5k \ 52 ¹ , 5k ^f ) as the valve body. 6. plunger according to claim 5t, characterized in that the The poppet valves are connected to one another via a valve rod (56) extending through the channel are. 7 tappet according to claim 5 or 6, characterized in that that the distance between the two poppet valves is adjustable. 8. tappet at least according to claim k, characterized in that one of the valve body is biased by a spring against the channel, and that each of the two valve bodies has such a mass inertia that one of the valve body sits above the predetermined oscillation frequency against the channel. 9, tappet at least according to claim k, characterized in that the valve bodies have different masses and one of the valve bodies is biased against the channel by a spring, the inertia of mass of each of the two valve bodies in their movement above the predetermined oscillation frequency 9Ü9831 / 0893 the same direction at different speeds and sitting one or the other
Causes valve body against the channel depending on the direction of movement of the cylinder. 10. tappet at least according to claim 9 »characterized in that the other valve body in the direction away from
the channel is biased by a spring. 11, plunger at least according to claims 9 and 10, characterized in that that the valve bodies are balls. 909831/0893