CN212359882U - Engine cylinder inner braking system and hydraulic tappet matched with same - Google Patents

Abstract

The utility model discloses a hydraulic tappet, include: the outer peripheral surface of the plunger is in sliding sealing fit with the inner peripheral surface of the tappet body, a communicating oil duct is arranged between an oil inlet and an oil outlet of the tappet body and the hydraulic cavity, and the pressure relief valve core is movably arranged at the position of the sealing conical surface through a limiting device. The utility model also discloses a braking system in compression release formula engine cylinder, its fuel feeding oil circuit connection liquid accuse ooff valve, engine machine oil circuit is connected to the oil inlet of liquid accuse ooff valve, and hydraulic tappet is connected to the oil-out, and when fuel feeding oil circuit and engine machine oil circuit intercommunication, the external oil feed passageway of hydraulic tappet is closed to the liquid accuse ooff valve, and when fuel feeding oil circuit and decompression oil circuit intercommunication, the external oil feed passageway of liquid accuse ooff valve intercommunication hydraulic tappet. The cylinder braking system is matched with the hydraulic tappet for use, so that the engine can exert the characteristic of cylinder braking and has the advantage of eliminating noise and impact caused by valve clearance and brought by the hydraulic tappet.

Description

Engine cylinder inner braking system and hydraulic tappet matched with same

Technical Field

The utility model relates to a braking technical field in the engine cylinder especially relates to a braking system in compression release formula engine cylinder, the utility model discloses still relate to the hydraulic tappet among the engine valve mechanism.

Background

In the valve actuating mechanism of the engine, a hydraulic tappet can be arranged on any transmission part between a cam and a valve, is used for transmitting the thrust of a camshaft to a push rod (or a valve rod) and bearing the lateral force applied when the camshaft rotates, and can automatically compensate valve clearance, eliminate relevant parts for adjusting the valve clearance and eliminate noise and impact caused by the valve clearance relative to a mechanical tappet.

In the cylinder braking technology of the engine, the compression release type braking technology is the best technology for the braking performance of the engine at present, and the basic principle is as follows: when the engine is dragged backwards, the piston compresses the gas in the cylinder to generate braking power in the process of ascending the compression stroke piston. Before the compression top dead center, the compression release type brake device drives the exhaust valve to open a certain opening degree, compressed high-temperature and high-pressure charging in the cylinder is discharged, at the moment, the pressure in the cylinder is rapidly reduced, after a certain crank angle, the exhaust valve is closed again, the piston moves downwards, and as the charging in the cylinder is greatly reduced, the working of the charging in the cylinder on the piston is also greatly reduced, and the counter braking power of the compression charging in the cylinder on the piston is reduced or eliminated.

Chinese patent application CN111197510A discloses an in-cylinder brake system for an engine, which includes an oil cylinder device, an oil pumping device and an oil supply device applied to a valve train of the engine, wherein all cylinders of the engine share one oil supply device; the oil supply device comprises an electromagnetic directional valve, an oil supply oil path, a pressure reducing oil path and a pressure relief oil path, the engine oil pressure of the engine before pressure reduction is P1, and the engine oil pressure of the engine after pressure reduction is P2; each cylinder of the engine is respectively provided with an oil cylinder device and an oil pumping device, the oil cylinder device is communicated with the oil pumping device through a pressure transmission oil path, the pressure transmission oil path is communicated with an oil supply oil path through a low-pressure relief valve, and the high end of an oil path system is provided with a relief valve; when braking is carried out in the cylinder, the air release valve is closed, the electromagnetic directional valve is electrified, engine oil with the pressure of P1 is provided for the pressure transmission oil path through the oil supply oil path, and the piston of the oil cylinder device and the plunger of the oil pumping device extend out; when the cam abuts against and pushes the oil pumping device, the engine oil pressure in the oil pumping device rises, the oil pumping device pumps high-pressure engine oil with the pressure of P to the oil cylinder device through the pressure transmission oil path, the low-pressure relief valve is closed, and the oil cylinder device pushes the rocker arm to open the valve, so that in-cylinder braking is realized; when the brake is not in the cylinder, the air release valve is opened, the electromagnetic directional valve is powered off, the oil with the pressure of P2 is provided for the pressure transmission oil path through the oil supply oil path, the low-pressure relief valve is in an opening state at the moment of power failure of the electromagnetic directional valve, the oil pressure in the pressure transmission oil path is relieved through the low-pressure relief valve and is reduced to P2, the oil cylinder device and the oil pumping device return respectively, the cam is separated from the oil pumping device, the engine is in a normal operation state, the oil or air in the pressure transmission oil path is continuously discharged through the air release valve, and the problem that the power transmission effect is seriously influenced due to the fact that air enters the pressure transmission oil. Because each cylinder of the engine is respectively provided with the oil cylinder device and the oil pumping device which are connected through the pressure transmission oil path, the pressure transmission oil path is communicated with the oil supply oil path of the oil supply device through the low-pressure relief valve, the brake/non-brake conversion of all cylinders of the whole engine can be realized only by controlling the on/off of the electromagnetic directional valve, the requirement on a control circuit is low, the work is stable and reliable, and the failure rate is low; and the structure is simple, the arrangement is flexible and convenient, the engine cylinder number is not limited, the number of the cylinders is even or odd, the application performance is good, and the application is wider.

When the in-cylinder braking system is applied to a dual-valve actuating mechanism, as shown in fig. 1, the rocker arm drives two valves (two intake valves or two exhaust valves) through the valve bridge, but when the in-cylinder braking system is applied to an engine cylinder, the in-cylinder braking mechanism drives one valve to open alone, if a traditional hydraulic tappet is configured on the valve actuating mechanism, for example, the hydraulic tappet disclosed in the chinese utility model patent application CN202020925895.0, the following problems can exist:

when the brake is in the cylinder, the brake mechanism drives one of the valves to open, the valve bridge moves downwards, but the rocker arm does not move relatively, at the moment, the hydraulic tappet extends to automatically compensate the gap formed by the descending of the valve bridge, and after the brake is finished in the cylinder, the valve is closed, and at the moment, because the hydraulic tappet is not shortened in time, the valve cannot be completely closed, the valve cannot be sealed in the subsequent working process, compressed gas in the cylinder leaks, and the brake effect in the cylinder is reduced or even fails.

SUMMERY OF THE UTILITY MODEL

The above-mentioned not enough to prior art, the utility model provides a hydraulic tappet suitable for braking in jar, as same design, the utility model also provides a compression release formula engine braking system in jar, this braking system in jar can use with above-mentioned hydraulic tappet is supporting, makes the engine not only can exert the extra long of braking in the jar but also have the noise that the elimination that the hydraulic tappet brought is aroused by the valve clearance and the advantage of assaulting.

For solving the first technical problem, the utility model discloses a technical scheme be:

a hydraulic tappet comprising: the hydraulic oil cylinder comprises a tappet body and a plunger, wherein one end of the tappet body is provided with an oil inlet and an oil outlet, and the other end of the tappet body is opened; the outer peripheral surface of the plunger piston is in sliding sealing fit with the inner peripheral surface of the tappet body; a communicating oil duct is arranged between the oil inlet and outlet and the hydraulic cavity, a sealing conical surface is arranged at the joint of the hydraulic cavity and the communicating oil duct, a pressure relief spring is arranged in the communicating oil duct, a pressure relief valve core is arranged in the hydraulic cavity, the pressure relief valve core is movably arranged at the sealing conical surface through a limiting device, the pressure relief valve core is jacked away from the sealing conical surface by the pressure relief spring to form an oil leakage gap when not acted by the opening pressure of the valve, and the pressure relief valve core overcomes the elasticity of the pressure relief spring and contacts with the sealing conical surface to realize the sealing of the hydraulic cavity when acted by the opening pressure of the valve; the hydraulic tappet is provided with an elastic device which enables the plunger to be in a retraction state after the engine oil pressure in the hydraulic cavity is eliminated.

The limiting device comprises a limiting seat, the limiting seat is fixed on the tappet body, the pressure relief valve core is placed on the limiting seat, the limiting seat is provided with an oil through hole, the elastic device comprises an extension spring arranged between the limiting seat and the plunger, and the extension spring is arranged in the hydraulic cavity.

The limiting device comprises a limiting seat, the limiting seat is fixed on the tappet body, the pressure relief valve core is placed on the limiting seat, the limiting seat is provided with an oil through hole, the elastic device comprises an extension spring connected between the tappet body and the plunger, and the extension spring is arranged outside the hydraulic cavity.

The limiting device comprises a limiting seat, the limiting seat is fixed on the tappet body, the pressure relief valve core is placed on the limiting seat, the limiting seat is provided with an oil through hole, the elastic device comprises a compression spring, one end of the compression spring abuts against the extending end of the plunger, the other end of the compression spring abuts against a component capable of generating relative displacement with the plunger, and the compression spring is arranged outside the hydraulic cavity.

The limiting device comprises a limiting spring, the limiting spring is clamped between the pressure relief valve core and the plunger, the elastic device comprises an extension spring connected between the tappet body and the plunger, and the extension spring is arranged outside the hydraulic cavity.

The limiting device comprises a limiting spring, the limiting spring is clamped and pressed between the pressure relief valve core and the plunger, the elastic device comprises a compression spring, one end of the compression spring abuts against the extending end of the plunger, the other end of the compression spring abuts against a component capable of generating relative displacement with the plunger, and the compression spring is arranged outside the hydraulic cavity.

For solving the second technical problem, the utility model discloses a technical scheme is:

a compression release type engine in-cylinder brake system comprises an oil supply device connected with an engine oil way of an engine, wherein the oil supply device comprises an electromagnetic directional valve, an oil supply way and a pressure reduction way; the oil supply path is connected with a control oil port of a hydraulic control switch valve, an oil inlet of the hydraulic control switch valve is connected with the engine oil path, an oil outlet of the hydraulic control switch valve is connected with an oil inlet of a tappet body of the hydraulic tappet, when the oil supply path is communicated with the engine oil path, the hydraulic control switch valve closes the connection between the hydraulic tappet and an external oil path, and when the oil supply path is communicated with the pressure reduction oil path, the hydraulic control switch valve opens the connection between the hydraulic tappet and the external oil path.

The hydraulic control switch valve comprises a valve body, the valve body is provided with the control oil port, the oil outlet and the oil inlet respectively, a valve core and a return spring are arranged in the valve body and fixed by a valve cover, and the valve core is provided with a communication hole for communicating the oil inlet and the oil outlet.

After the technical scheme is adopted, the utility model discloses the technological effect who reaches is:

the utility model discloses an engine in-cylinder braking system is the system that adopts control machine oil to realize the braking.

When the engine works in a non-cylinder braking mode, the electromagnetic directional valve of the oil supply device is powered off, the oil supply oil path is connected with the low-pressure oil path through the electromagnetic directional valve, at the moment, the hydraulic control switch valve is communicated with the hydraulic tappet and the external oil path, if the cam does not work, the hydraulic plunger is not acted by the opening pressure of the valve, the pressure relief valve core is jacked away from the sealing conical surface by the pressure relief spring, engine oil enters the hydraulic cavity through the oil inlet and outlet and the communicated oil path and slowly leaks through the gap between the pressure relief valve core and the sealing conical surface, at the moment, the tappet body and the plunger of the hydraulic tappet are respectively (directly or indirectly) close to the cam and the valve under the action of the oil pressure of the engine; if the cam works, the engine oil pressure of the hydraulic cavity rises, the pressure relief valve core overcomes the elasticity of the pressure relief spring and is in contact with the sealing conical surface, the hydraulic cavity becomes a closed cavity, no matter how the rotating speed of the engine changes, the relative position of the tappet body and the plunger cannot change, and the performance of the engine is ensured. Because the oil leakage gap can be formed between the pressure relief valve core and the sealing conical surface, when the cam does not work, engine oil of an engine can enter and exit the hydraulic cavity through the oil inlet and outlet and the oil leakage gap, the working length of the hydraulic tappet can be extended and shortened, and the thermal expansion gap of a valve mechanism part can be automatically compensated; when the cam works, the pressure relief valve core is sealed with the sealing conical surface, the working length of the hydraulic tappet is almost unchanged (only slightly shortened at the initial stage of the cam work, and the shortening amount is controllable), and the opening stroke of the valve is more accurate.

When the engine works in an in-cylinder braking mode, the electromagnetic directional valve is electrified, the oil supply oil path is communicated with an engine oil path (high-pressure oil path) of the engine through the electromagnetic directional valve, the hydraulic control switch valve closes the connection between the hydraulic tappet and an external oil path under the action of high-pressure oil, and the hydraulic tappet does not extend under the action of the elastic device, so that the valve clearance is not automatically compensated, and the braking effect is not influenced. The engine cylinder braking system is matched with the hydraulic tappet for use, so that the engine can not only exert the characteristic of cylinder braking, but also has the advantage of eliminating noise and impact caused by valve clearance and brought by the hydraulic tappet.

The utility model discloses a hydraulic tappet can also use with the supporting of the in-cylinder braking system of other structural style, and at this moment, the on/off mode of machine oil can adopt the electromagnetic switch valve to realize, also can be through other modes. When the hydraulic tappet is in a non-cylinder braking state, engine oil of the engine is communicated with the hydraulic cavity, the pressure of the engine oil overcomes the elasticity of the elastic device, and the hydraulic tappet extends and has the same working principle as that of the traditional hydraulic tappet. When the engine is in a braking state in the cylinder, the engine oil circuit is disconnected, and the hydraulic tappet is shortened under the action of the elastic force of the elastic device, so that the valve clearance is not automatically compensated. In the braking state in the cylinder, as long as the connection between the engine oil path of the engine and the oil inlet of the hydraulic tappet is controlled to be disconnected, the hydraulic tappet can not extend any more (the shortening amount can be ensured by mechanical limitation and cannot be too short), so that the braking effect is ensured.

Drawings

FIG. 1 is a schematic diagram of a known dual valve train;

FIG. 2 is a cross-sectional view of a first configuration of a hydraulic tappet of the present invention;

FIG. 3 is a cross-sectional view of a second configuration of a hydraulic tappet according to the present invention;

FIG. 4 is a cross-sectional view of a third configuration of a hydraulic tappet according to the present invention;

FIG. 5 is a cross-sectional view of a fourth configuration of the hydraulic tappet of the present invention;

FIG. 6 is a cross-sectional view of a fifth configuration of a hydraulic tappet according to the present invention;

FIG. 7 is a schematic structural diagram of an embodiment of a compression-release engine in-cylinder braking system for use with a hydraulic tappet according to the present invention;

in the figure:

10-cam, 20-push rod, 30-rocker arm, 40-hydraulic tappet, 50-valve spring, 60-valve, 61-valve bridge, 70-orifice, 80-electromagnetic directional valve, 90-one-way valve, 100-overflow pressure retaining valve, F-cylinder brake force application direction;

l0-engine oil circuit, La-oil supply circuit, Lb-pressure reducing circuit, Lc-pressure reducing circuit;

40B-hydraulic tappet, 41B-plunger, 42B-tappet body, 421B-oil inlet and outlet, 43B-hydraulic cavity, 44B-limiting spring, 45B 1-extension spring, 45B 2-extension spring, 45B 3-compression spring, 46B-sealing conical surface, 47B-pressure relief valve core, 48B-pressure relief spring, 49B-limiting seat and 49B 1-oil through hole;

110-hydraulic control switch valve, 1101-valve body, 1102-control oil port, 1103-oil outlet, 1104-oil inlet, 1105-valve core, 1106-communication hole, 1107-return spring and 1108-valve cover.

Detailed Description

The present invention will be further explained with reference to the drawings and examples.

As shown in fig. 7, a compression-release in-cylinder brake system for an engine is a system that uses control oil to perform braking. The oil supply device comprises an electromagnetic directional valve 80, an oil supply line La and a pressure reducing oil line Lb, wherein the oil supply device is connected with the engine oil line L0 and comprises the electromagnetic directional valve 80, the oil supply line La and the pressure reducing oil line Lb, the pressure reducing oil line Lb is connected with a pressure reducing oil line Lc, and the oil supply line La is selectively communicated with the engine oil line L0 and the pressure reducing oil line Lb through the electromagnetic directional valve 80. The electromagnetic directional valve 80 is preferably a two-position three-way electromagnetic directional valve, and a check valve 90 is further arranged in front of the electromagnetic directional valve 80, and the check valve 90 can further protect the engine oil passage L0 from being impacted by the returned high-pressure engine oil. An overflow pressure retaining valve 100 is arranged in the pressure relief oil passage Lc. For convenience of description, the oil pressure of the engine oil passage L0 before decompression is defined as P1, P1 as high pressure, the oil pressure of the engine after decompression is defined as P2, P2 as low pressure, and the set pressure of the overflow pressure-retaining valve 100 is P2 or slightly higher than P2. The detailed structure and working principle of the in-cylinder brake system of the engine are referred to the chinese patent application CN111197510A, which is not described herein.

As shown in fig. 7, the oil supply path La is connected to the control oil port 1102 of the pilot-controlled switch valve 110, the oil inlet 1104 of the pilot-controlled switch valve 110 is connected to the engine oil path P0, the oil outlet 1103 of the pilot-controlled switch valve is connected to the hydraulic tappet 40B, when the oil supply path La is communicated with the engine oil path L0, the pilot-controlled switch valve 110 closes the external oil inlet channel of the hydraulic tappet 40B under the action of the high-pressure oil P1, and when the oil supply path La is communicated with the pressure reducing path Lb, the pilot-controlled switch valve 110 opens the external oil inlet channel of the hydraulic tappet 40B.

As shown in fig. 7, the hydraulic control switch valve 110 has a specific structure that a control oil port 1102, an oil outlet 1103 and an oil inlet 1104 are respectively formed on a valve body 1101, a valve spool 1105 and a return spring 1107 are arranged in the valve body 1101 and fixed by a valve cover 1108, and the valve spool 1105 is provided with a communication hole 1106. Fig. 7 shows a state when the hydraulic tappet 40B is in communication with an external oil inlet channel, at this time, the system is in a non-cylinder braking state, the electromagnetic directional valve 80 is de-energized, the oil supply path La is in communication with the pressure reduction path Lb, the pressure of the control oil port 1102 is low pressure P2, the return spring 1107 pushes the valve core 1105 leftward, and the communication hole 1106 is in a position in which the communication hole is in communication with the oil inlet 1104 and the oil outlet 1103 at the same time. When the system is in an in-cylinder braking state, the electromagnetic directional valve 80 is electrified, the oil supply passage La is communicated with the engine oil passage L0, the pressure of the control oil port 1102 is high pressure P1, the high pressure P1 overcomes the elastic force of the return spring 1107 to push the valve element 1105 towards the right, the oil inlet 1104 cannot be communicated with the oil outlet 1103 through the communication hole 1106, and therefore the connection between the engine oil passage L0 and the hydraulic tappet oil passage is cut off.

Fig. 2 shows a specific structure of the first hydraulic tappet 40B. The oil inlet/outlet 421B is formed at one end of the tappet body 42B, and the other end is open, the plunger 41B extends from the open end of the tappet body 42B and forms a hydraulic chamber 43B with the tappet body 42B, and the oil inlet/outlet 421B is communicated with an engine oil passage (not shown) provided on the rocker arm 30.

The outer peripheral surface of the plunger 41B is slidably fitted to the inner peripheral surface of the tappet body 42B, and the fitting clearance ensures smooth sliding and sealing of the plunger, so that oil does not leak therefrom. A communication oil channel is arranged between the oil inlet/outlet 421B and the hydraulic cavity 43B, a sealing conical surface 46B is arranged at the joint of the hydraulic cavity 43B and the communication oil channel, a pressure relief spring 48B is arranged in the communication oil channel, and the pressure relief spring 48B abuts against a step surface of the pressure relief valve core 47B and the communication oil channel. A limiting seat 49B and a pressure relief valve core 47B are arranged in the hydraulic cavity 43B, the limiting seat 49B is fixed on the tappet body 42B, the pressure relief valve core 47B is placed on the limiting seat 49B, the limiting seat 49B is provided with an oil through hole 49B1, and the pressure relief valve core 47B is movably installed on the sealing conical surface 46B through the limiting seat 49B. Preferably, the pressure relief valve spool 47B comprises a valve ball, such as a steel ball. When the pressure relief valve is not acted by the valve opening pressure, the elastic force of the pressure relief spring 48B ensures that the pressure relief valve core 47B can be separated from the sealing conical surface 46B to form an oil leakage gap. When acted by the valve opening pressure, the hydraulic chamber 43B is pressurized, and the relief valve element 47B overcomes the elastic force of the relief spring 48B and contacts the sealing conical surface 46B to seal the hydraulic chamber 43B.

An extension spring 45B1 which enables the plunger 41B to be in a retraction state after oil pressure in the hydraulic cavity 43B is eliminated is arranged between the limiting seat 49B and the plunger 41B, under the condition that the engine oil pressure is cut off in the in-cylinder braking state, the plunger 41B can not extend out due to the tension of the extension spring 45B1, and after the in-cylinder braking is finished, the closing of the valve cannot be influenced, so that the braking effect cannot be influenced. In this embodiment, one end of the extension spring 45B1 is fixedly connected to the plunger 41B, and the other end is fixedly connected to the limit seat 49B.

Combine theory of operation, the utility model discloses the technological effect who gains is:

when the engine works in a non-cylinder braking mode, the electromagnetic directional valve 80 of the oil supply device is powered off, the oil supply line La is communicated with the low-pressure oil line Lb through the electromagnetic directional valve 80, at the moment, the hydraulic control switch valve 110 is connected with the hydraulic tappet 40B and an external oil line, when the cam 10 does not work (the cam 10 does not rotate to a working surface), the hydraulic tappet is not acted by the opening pressure of the valve, the pressure relief valve core 47B is jacked away from the sealing conical surface 46B by the pressure relief spring 48B, engine oil enters the hydraulic cavity 43B through the oil inlet and outlet 421B and the communication oil passage, at the moment, under the action of the pressure of the engine oil, the tappet body 42B and the plunger 41B of the hydraulic tappet are respectively (directly or indirectly) close to the cam 10 and the valve 60, the valve clearance is eliminated, and the telescopic automatic compensation parts are influenced by thermal. When the cam works (the cam 10 rotates to a working surface), the oil pressure of the hydraulic cavity 43B rises, the pressure relief valve core 47B overcomes the elastic force of the pressure relief spring 48B, the hydraulic cavity 43B becomes a closed cavity, no matter how the engine speed changes, the relative position of the tappet body 42B and the plunger 41B cannot change, and the performance of the engine is ensured.

When the engine works in the in-cylinder braking mode, the electromagnetic directional valve 80 is electrified, the oil supply oil path La is communicated with an engine oil path L0 (high-pressure oil path) through the electromagnetic directional valve 80, the hydraulic control switch valve 110 closes the connection between the hydraulic tappet 40B and an external oil path under the action of high-pressure oil P1, and the hydraulic tappet 40B does not extend under the action of the extension spring 45B1, so that the valve clearance is not automatically compensated any more, and the braking effect is not influenced. Therefore, the in-cylinder brake system of the engine is matched with the hydraulic tappet for use, so that the engine can not only exert the characteristic of in-cylinder braking, but also has the advantage of eliminating noise and impact caused by the valve clearance and brought by the hydraulic tappet.

The utility model discloses in, hydraulic tappet 40B's structure is more than one.

Fig. 3 shows a second structure of the hydraulic tappet 40B, and in comparison with the first hydraulic tappet 40B shown in fig. 2, the extension spring 45B2 of the hydraulic tappet 40B of the second structure is connected between the tappet body 42B and the plunger 41B and is disposed outside the hydraulic pressure chamber 43B. Both functions are the same, and the plunger 41B is in the retracted state after the oil pressure in the hydraulic chamber 43B is removed.

FIG. 4 illustrates a third configuration of a hydraulic tappet 40B, which utilizes a compression spring as compared to the first hydraulic tappet 40B shown in FIG. 2, but functions in the same manner to retract the plunger 41B after oil pressure in the hydraulic chamber 43B is removed. As shown in fig. 4, the compression spring 45B3 has one end abutting against the protruding end of the plunger 41B and the other end abutting against a member that is displaceable relative to the plunger 41B (in this embodiment, the other end of the compression spring 45B3 abuts against the valve bridge 60), and is disposed outside the hydraulic chamber 43B.

Fig. 5 shows a fourth configuration of the hydraulic tappet 40B, in which, compared to the second hydraulic tappet 40B shown in fig. 3, the second hydraulic tappet 40B employs a limit seat 49B, which is a rigid mounting structure, and the fourth hydraulic tappet 40B employs a limit spring 44B, which is an elastic mounting structure, and the limit spring 44B is sandwiched between the relief valve element 47B and the plunger 41B. The stopper seat 49B and the stopper spring 44B are different in structure, but are both stopper devices, and both function to movably mount the relief valve element 47B to the seal tapered surface 46B.

Fig. 6 shows a fifth structure of the hydraulic tappet 40B, and compared with the third hydraulic tappet shown in fig. 4, the third hydraulic tappet 40B employs a limit seat 49B and is a rigid mounting structure, while the fifth hydraulic tappet 40B employs a limit spring 44B and is an elastic mounting structure, and the limit spring 44B is clamped between the pressure relief valve core 47B and the plunger 41B. The stopper seat 49B and the stopper spring 44B are different in structure, but are both stopper devices, and both function to movably mount the relief valve element 47B to the seal tapered surface 46B.

In the above-described configurations of the hydraulic tappet 40B, the extension spring or the compression spring is essentially an elastic device, so long as the plunger 41B is in a retracted state after the oil pressure in the hydraulic chamber 43B is removed.

The utility model discloses in, hydraulic tappet 40B also can use with the supporting of the in-cylinder braking system of the form of other structures, and at this moment, tappet body 42B's oil inlet will be connected by switch valve controlled engine oil circuit, and this ooff valve can be the pilot operated switch valve also can be electromagnetic switch valve.

The utility model discloses in, hydraulic tappet 40B's the position that sets up is not restricted to the rocking arm, and it can set up on any one transmission part between the cam to the valve of engine valve mechanism.

The present invention is not limited to the above embodiments, and all improvements based on the concept, principle, structure and method of the present invention will fall within the protection scope of the present invention.

Claims (10)

1. A hydraulic tappet comprising:

the hydraulic oil cylinder comprises a tappet body and a plunger, wherein one end of the tappet body is provided with an oil inlet and an oil outlet, and the other end of the tappet body is opened;

the outer peripheral surface of the plunger piston is in sliding sealing fit with the inner peripheral surface of the tappet body;

a communicating oil duct is arranged between the oil inlet and outlet and the hydraulic cavity, a sealing conical surface is arranged at the joint of the hydraulic cavity and the communicating oil duct, a pressure relief spring is arranged in the communicating oil duct, a pressure relief valve core is arranged in the hydraulic cavity, the pressure relief valve core is movably arranged at the sealing conical surface through a limiting device, the pressure relief valve core is jacked away from the sealing conical surface by the pressure relief spring to form an oil leakage gap when not acted by the opening pressure of the valve, and the pressure relief valve core overcomes the elasticity of the pressure relief spring and contacts with the sealing conical surface to realize the sealing of the hydraulic cavity when acted by the opening pressure of the valve; it is characterized in that the preparation method is characterized in that,

the hydraulic tappet is provided with an elastic device which enables the plunger to be in a retraction state after the engine oil pressure in the hydraulic cavity is eliminated.

2. The hydraulic tappet of claim 1, wherein the limiting device comprises a limiting seat fixed to the tappet body, the pressure relief valve spool is disposed on the limiting seat, the limiting seat is provided with an oil through hole, the elastic device comprises an extension spring disposed between the limiting seat and the plunger, and the extension spring is disposed in the hydraulic cavity.

3. The hydraulic tappet of claim 1, wherein the limiting device comprises a limiting seat fixed to the tappet body, the pressure relief valve spool is disposed on the limiting seat, the limiting seat is provided with an oil through hole, the elastic device comprises an extension spring connected between the tappet body and the plunger, and the extension spring is disposed outside the hydraulic chamber.

4. The hydraulic tappet according to claim 1, wherein the limiting device comprises a limiting seat fixed to the tappet body, the pressure relief valve spool is disposed on the limiting seat, the limiting seat is provided with an oil through hole, the elastic device comprises a compression spring, one end of the compression spring abuts against an extending end of the plunger, the other end of the compression spring abuts against a component capable of generating relative displacement with the plunger, and the compression spring is disposed outside the hydraulic cavity.

5. The hydraulic lifter of claim 1, wherein the limiting device comprises a limiting spring sandwiched between the pressure relief valve spool and the plunger, and the resilient device comprises an extension spring coupled between the lifter body and the plunger, the extension spring disposed outside the hydraulic chamber.

6. The hydraulic tappet of claim 1, wherein the limiting device comprises a limiting spring sandwiched between the pressure relief valve element and the plunger, and the resilient device comprises a compression spring having one end abutting against an extended end of the plunger and the other end abutting against a member that is displaceable relative to the plunger, the compression spring being disposed outside the hydraulic chamber.

7. The hydraulic tappet of claim 1, wherein the oil inlet and the oil outlet of the tappet body are connected with an engine oil path controlled by a switching valve.

8. The hydraulic tappet of claim 7, wherein the switching valve is a solenoid switching valve or a pilot operated switching valve.

9. An in-cylinder engine braking system comprising

The oil supply device is connected with an engine oil path of the engine and comprises an electromagnetic directional valve, an oil supply path and a pressure reducing path, the pressure reducing path is connected with a pressure reducing path, an overflow pressure retaining valve is arranged in the pressure reducing path, and the oil supply path is selectively communicated with the engine oil path of the engine and the pressure reducing path through the electromagnetic directional valve; it is characterized in that the preparation method is characterized in that,

the oil supply path is connected with a control oil port of a hydraulic control switch valve, an oil inlet of the hydraulic control switch valve is connected with the engine oil path, an oil outlet of the hydraulic control switch valve is connected with an oil inlet and an oil outlet of the tappet body of the hydraulic tappet according to any one of claims 1 to 6, when the oil supply path is communicated with the engine oil path, the hydraulic control switch valve closes the connection between the hydraulic tappet and an external oil path, and when the oil supply path is communicated with the pressure reduction oil path, the hydraulic control switch valve opens the connection between the hydraulic tappet and the external oil path.

10. The engine in-cylinder brake system of claim 9, wherein the hydraulic control switch valve includes a valve body, the valve body is respectively provided with the control oil port, the oil outlet, and the oil inlet, a valve core and a return spring are disposed in the valve body and fixed by a valve cover, and the valve core is provided with a communication hole for communicating the oil inlet and the oil outlet.

Images