Hydraulic tappet assembling mechanism

Abstract

The utility model discloses a hydraulic tappet assembling mechanism which comprises a tappet connecting part arranged at one end of a rocker arm, the tappet connecting part is provided with a first oil way communicated with an engine oil way of an engine, a bowl seat is installed at the end, facing a hydraulic tappet, of the tappet connecting part, and the hydraulic tappet is installed on a valve bridge. The bottom of the bowl base abuts against the hydraulic tappet. The bottom of the bowl base is provided with a flow limiting hole communicating with the first oil way and an oil inlet of the hydraulic tappet. When braking is carried out in an engine cylinder, an oil drainage gap can be generated between the bowl seat and the hydraulic tappet, at the moment, the end face, facing the bowl seat, of the hydraulic tappet is an inclined face, hydraulic oil flowing out of the flow limiting hole flows away along the inclined face and does not flow into an oil inlet of the hydraulic tappet, the hydraulic tappet does not extend any more without continuous supply of the hydraulic oil, and when braking is finished, a valve is closed, and the hydraulic tappet is stopped. The hydraulic tappet immediately recovers to a normal working state; the assembling mechanism can be well matched with an in-cylinder braking system of the engine, and it is guaranteed that the engine is kept in a high-performance working state.

Description

Technical Field

[0001] The utility model relates to the technical field of engines, in particular to a hydraulic tappet assembly mechanism. Background Art

[0002] In the engine valve train, a hydraulic tappet can be installed on any transmission component between the cam and the valve, and is used to transmit the thrust of the camshaft to the push rod (or valve stem), and bear the lateral force exerted during the rotation of the camshaft. Compared with a mechanical tappet, the hydraulic tappet can automatically compensate for the valve clearance, cancel the related components for adjusting the valve clearance, and eliminate the noise and impact caused by the valve clearance.

[0003] In the engine cylinder internal braking technology, the compression release braking technology is currently the technology with the best braking performance of the engine. Its basic principle is: when the engine is dragged backwards, during the upward movement of the piston in the compression stroke, the piston compresses the gas in the cylinder to generate braking power. Before the compression top dead center, the exhaust valve is driven to open a certain opening by the compression release braking device, and the compressed high-temperature and high-pressure charge in the cylinder is discharged. At this time, the pressure in the cylinder drops rapidly. After a certain crankshaft angle, the exhaust valve closes again, and the piston moves downward. Since the charge in the cylinder has been greatly reduced, the work done by the charge in the cylinder on the piston is also greatly reduced, reducing or eliminating the reverse braking power generated by the compressed charge in the cylinder on the piston.

[0004] When applying the cylinder internal braking system to a two-valve valve train, the rocker arm drives two valves (two intake valves or two exhaust valves) simultaneously through a valve bridge. However, during engine cylinder internal braking, the cylinder internal braking mechanism drives only one valve to open. If a traditional hydraulic tappet is configured on the valve mechanism, such as the hydraulic tappet disclosed in the patent application CN111472859A, the following problems will occur:

[0005] During the cylinder internal braking state, the cylinder internal braking mechanism drives one of the valves to open, and the valve bridge moves downward, but the rocker arm does not move relatively. At this time, the hydraulic tappet elongates to automatically compensate for the gap formed by the downward movement of the valve bridge. When the cylinder internal braking ends and the valve closes, since the hydraulic tappet is not shortened in time, the valve cannot be completely closed, resulting in that during the subsequent working process, the valve cannot be sealed, and the compressed gas in the cylinder leaks, reducing the cylinder internal braking effect or even causing failure.

[0006] Patent application CN111535893A discloses an in-cylinder engine braking system and its supporting hydraulic tappet, and proposes a solution. During in-cylinder braking, the hydraulic oil connection oil path of the hydraulic tappet is cut off, and the compression spring inside the hydraulic tappet is replaced with a tension spring, so that the hydraulic tappet no longer "extends", solving the air leakage problem caused by valve extension. However, during in-cylinder braking, when the valve opens under the combined action of the valve spring force and the camshaft thrust, the hydraulic tappet continuously "shortens", and a gap will be generated between the hydraulic tappet and the valve (or other components such as the valve bridge). When the valve closes during the exhaust stroke, an impact will occur, affecting the service life of the moving parts. Utility Model Content

[0007] The technical problem to be solved by the present utility model is to provide a hydraulic tappet assembly mechanism.

[0008] To solve the above technical problem, the technical solution of the present utility model is: A hydraulic tappet assembly mechanism, the hydraulic tappet is installed between the rocker arm and the valve bridge. This assembly mechanism includes a tappet connection part provided at one end of the rocker arm. The tappet connection part is provided with a first oil path communicating with the engine's oil oil path. The end of the tappet connection part facing the hydraulic tappet is installed with a bowl seat. The hydraulic tappet is installed on the valve bridge, and the bottom of the bowl seat abuts against the hydraulic tappet; a flow-limiting hole communicating the first oil path and the hydraulic tappet oil inlet is provided at the bottom of the bowl seat.

[0009] Preferably, an installation hole is provided on the valve bridge, the hydraulic tappet is installed in the installation hole, and the valve bridge also serves as the tappet body of the hydraulic tappet.

[0010] Preferably, the hydraulic tappet includes a plunger and a pressure relief component. A hydraulic chamber opening towards the pressure relief component is provided inside the plunger. The oil inlet of the hydraulic tappet is provided on the plunger. The oil inlet communicates the hydraulic chamber and the flow-limiting hole. A check valve opening towards the hydraulic chamber is installed between the oil inlet and the hydraulic chamber; the pressure relief component includes a pressure relief passage communicating with the hydraulic chamber, and a pressure relief control valve is installed in the pressure relief passage.

[0011] Preferably, the pressure relief control valve includes a valve seat. The pressure relief passage includes a stepped hole communicating with the hydraulic chamber. The valve seat is installed in the stepped hole; the pressure relief passage further includes a pressure relief hole communicating with the stepped hole. A sealing conical surface is provided between the stepped hole and the pressure relief hole. A valve core cooperating with the sealing conical surface is installed between the valve seat and the pressure relief hole. A pressure relief spring for pushing the valve core away from the sealing conical surface is installed in the pressure relief hole.

[0012] Preferably, an oil passing gap communicating the hydraulic chamber and the pressure relief hole is provided between the valve seat and the stepped hole.

[0013] Preferably, an oil passage hole communicating the hydraulic chamber and the pressure relief hole is provided on the valve seat.

[0014] Preferably, the valve core is a spherical valve core.

[0015] Preferably, the pressure relief hole communicates with the oil pan.

[0016] Preferably, a tension spring is installed in the hydraulic chamber. One end of the tension spring is fixedly connected to the inner wall of the hydraulic chamber, and the other end of the tension spring is fixedly connected to the inner wall of the installation hole.

[0017] Preferably, a compression spring surrounding the tappet connecting portion and the cup seat is installed between the rocker arm and the valve bridge.

[0018] The beneficial effects of the present application are as follows:

[0019] In the hydraulic tappet assembly mechanism of the present application, the hydraulic tappet is installed between the rocker arm and the valve bridge. The assembly mechanism includes a tappet connecting portion provided at one end of the rocker arm. The tappet connecting portion is provided with a first oil passage communicating with the engine oil oil circuit. A cup seat is installed at the end of the tappet connecting portion facing the hydraulic tappet. The hydraulic tappet is installed on the valve bridge, and the bottom of the cup seat abuts against the valve bridge; a flow limiting hole communicating the first oil passage and the hydraulic tappet oil inlet is provided at the bottom of the cup seat; when the engine cylinder internal braking is performed, an oil leakage gap will be generated between the cup seat and the hydraulic tappet. At this time, the end face of the hydraulic tappet facing the cup seat is an inclined surface, and the hydraulic oil flowing out of the flow limiting hole flows along the inclined surface and will not flow into the oil inlet of the hydraulic tappet. The hydraulic tappet no longer elongates without continuous supply of hydraulic oil. When the braking ends and the valve closes, the hydraulic tappet immediately returns to the normal working state; the assembly mechanism can cooperate well with the engine cylinder internal braking system to ensure that the engine maintains a high-performance working state. Description of the Drawings

[0020] The following drawings are only intended to illustrate and explain the present invention schematically and do not limit the scope of the present invention. Among them:

[0021] Figure 1 is the structural schematic diagram of the first embodiment of the present invention Figure 1 ;

[0022] Figure 2 is the structural schematic diagram of the first embodiment of the present invention Figure 2 ;

[0023] Figure 3 is Figure 2 the enlarged view at I in

[0024] Figure 4 It is a schematic structural diagram of the second embodiment of the present utility model;

[0025] Figure 5 is Figure 4 the enlarged view at position II in

[0026] Figure 6 It is a schematic structural diagram of the third embodiment of the present utility model;

[0027] Figure 7 is Figure 6 the enlarged view at position III in

[0028] Figure 8 It is the valve stroke curve diagram during the braking process of the present utility model;

[0029] In the figure: 11 - rocker arm; 12 - push rod; 13 - cam; 14 - valve bridge; 15 - screw; 16 - first oil passage; 17 - bowl seat; 18 - flow limiting orifice; 21 - plunger; 22 - oil inlet; 23 - hydraulic cavity; 24 - check valve; 31 - pressure relief passage; 32 - valve seat; 33 - sealing cone surface; 34 - valve core; 35 - pressure relief spring; 4 - tension spring; 5 - compression spring; 61 - valve stem; 62 - valve spring. Detailed implementation manners

[0030] The present utility model will be further described below in conjunction with the drawings and embodiments. In the following detailed description, only some exemplary embodiments of the present utility model are described by way of illustration. Undoubtedly, those of ordinary skill in the art can recognize that the described embodiments can be modified in various different ways without departing from the spirit and scope of the present utility model. Therefore, the drawings and the description are illustrative in nature and are not used to limit the protection scope of the claims.

[0031] As Figure 1 , Figure 2 and Figure 3 shown, one end of the rocker arm 11 is installed with a push rod 12, and the other end of the rocker arm 11 is connected to the valve bridge 14 through this hydraulic tappet assembly mechanism, and the push rod 12 is in contact with the cam 13 in a mating manner. A set of valve assemblies are respectively installed at both ends of the valve bridge 14. The valve assembly includes a valve stem 61 connecting the valve bridge 14 and the valve, and a valve spring 62 is installed on the valve stem 61.

[0032] A hydraulic tappet assembly mechanism, where the hydraulic tappet is installed between an end of a rocker arm 11 and a valve bridge 14. This assembly mechanism includes a tappet connection part provided at one end of the rocker arm 11. Of course, a screw 15 can also be installed at one end of the rocker arm 11, and the screw 15 is the tappet connection part. The screw 15 is used to adjust the valve clearance, and the screw 15 is threadedly connected to the rocker arm 11. A bolt can also be used instead of the screw 15; the tappet connection part is provided with a first oil passage 16 communicating with the engine's oil circuit. An end of the tappet connection part facing the hydraulic tappet is installed with a bowl seat 17. The hydraulic tappet is installed on the valve bridge 14, and the bottom of the bowl seat 17 abuts against the hydraulic tappet; the bowl seat 17 adopts an elephant-foot bowl seat 17; the bottom of the bowl seat 17 is provided with a flow-limiting hole 18 communicating the first oil passage 16 and the hydraulic tappet oil inlet 22.

[0033] The valve bridge 14 is provided with a mounting hole, and the hydraulic tappet is installed in the mounting hole. The valve bridge 14 also serves as the tappet body of the hydraulic tappet. The hydraulic tappet includes a plunger 21 and a pressure relief component. The plunger 21 is slidably installed in the mounting hole; a hydraulic chamber 23 opening towards the pressure relief component is provided in the plunger 21. The oil inlet 22 of the hydraulic tappet is provided on the plunger 21. The oil inlet 22 communicates the hydraulic chamber 23 and the flow-limiting hole 18. A one-way valve 24 opening towards the hydraulic chamber 23 is installed between the oil inlet 22 and the hydraulic chamber 23; the pressure relief component includes a pressure relief passage 31 communicating with the hydraulic chamber 23, and a pressure relief control valve is installed in the pressure relief passage 31.

[0034] The pressure relief control valve includes a valve seat 32. The pressure relief passage 31 includes a stepped hole communicating with the hydraulic chamber 23, and the valve seat 32 is installed in the stepped hole; the pressure relief passage 31 further includes a pressure relief hole communicating with the stepped hole. A sealing cone surface 33 is provided between the stepped hole and the pressure relief hole. A valve core 34 cooperating with the sealing cone surface 33 is installed between the valve seat 32 and the pressure relief hole. A pressure relief spring 35 that pushes the valve core 34 away from the sealing cone surface 33 is installed in the pressure relief hole. The valve core 34 is a spherical valve core 34, and the spherical valve core 34 cooperates with the sealing cone surface 33.

[0035] An oil passage gap communicating the hydraulic chamber 23 and the pressure relief hole is provided between the valve seat 32 and the stepped hole. It can ensure that the oil in the hydraulic chamber 23 can flow smoothly into the pressure relief passage 31. Or, an oil passage hole (not shown in the figure) communicating the hydraulic chamber 23 and the pressure relief hole is provided on the valve seat 32. The function of the oil passage hole is the same as that of the oil passage gap, which is to facilitate the oil in the hydraulic chamber 23 to enter the pressure relief passage 31. The pressure relief hole communicates with the oil sump.

[0036] Working principle:

[0037] When the cam 13 is not working (the cam 13 has not rotated to the working surface), since the hydraulic tappet is not under the action of the valve opening pressure at this time, the valve core 34 of the pressure relief control valve is pushed away from the sealing cone surface 33 of the pressure relief passage 31 by the pressure relief spring 35 to form an oil leakage gap. Engine oil enters the hydraulic chamber 23 through the oil inlet 22 and the one-way valve 24, and slowly leaks through the gap between the pressure relief valve core 34 and the sealing cone surface 33. At this time, under the action of the engine oil pressure, the plunger 21 of the hydraulic tappet is close to the cam 13 and the valve, eliminating the valve clearance, and can telescopically and automatically compensate for the influence of various components due to thermal expansion and contraction, etc. When the cam 13 is working (the cam 13 rotates to the working surface), the oil pressure in the hydraulic chamber 23 increases, the pressure relief valve core 34 overcomes the elastic force of the pressure relief spring 35, and the hydraulic chamber 23 becomes a closed chamber. Compared with the traditional hydraulic tappet (the working length is shortened), regardless of how the engine speed changes, the relative position between the tappet body and the plunger 21 will not change, ensuring the performance of the engine.

[0038] During the in-cylinder braking process, at the moment under the action of the braking force F, one of the valves sinks, and the valve bridge 14 moves simultaneously. An oil leakage gap is generated between the plunger 21 and the bowl seat 17, and the plane where the plunger 21 contacts the bowl seat 17 tilts. The hydraulic oil flowing into the hydraulic tappet through the bowl seat 17 is depressurized through the oil leakage gap. Without continuous supply of hydraulic oil to the hydraulic tappet, the pressure in the hydraulic chamber 23 relatively increases, and the one-way valve 24 at the oil inlet 22 of the plunger 21 closes, and the hydraulic tappet no longer extends, thus ensuring that the valve clearance remains unchanged; after this braking is completed, F becomes zero, and under the action of the valve spring force, the valve closes and returns to Figure 1 the state shown, and the bowl seat 17 continues to supply oil to the hydraulic tappet, and the hydraulic tappet returns to the normal working state. It is ensured that in the subsequent intake and exhaust strokes, the hydraulic tappet eliminates the valve clearance to ensure normal valve opening.

[0039] During the process of depressurizing the hydraulic oil through the oil leakage gap, the flow-limiting orifice 18 has two functions. One is to reduce the amount of oil discharged, and the other is to control the amount of oil flowing out of the flow-limiting orifice 18 to be discharged through the oil leakage gap, so that too much oil will not enter the hydraulic chamber 23 of the hydraulic tappet and cause the hydraulic tappet to "extend".

[0040] Compared with the prior art, this embodiment removes the return spring in the hydraulic chamber 23 of the hydraulic tappet, and the "extension" of the hydraulic tappet only depends on the pressure provided by the hydraulic oil, and the structure is simpler. This assembly mechanism can cooperate well with the in-cylinder braking system of the engine to ensure that the engine maintains a high-performance working state.

[0041] The difference between this embodiment and the first embodiment is that as Figure 4 and Figure 5As shown, a tension spring 4 is installed in the hydraulic chamber 23. One end of the tension spring 4 is fixedly connected to the inner wall of the hydraulic chamber 23, and the other end of the tension spring 4 is fixedly connected to the inner wall of the mounting hole.

[0042] In the first embodiment, the pressure of the hydraulic oil in the hydraulic chamber 23 is used to keep the length of the hydraulic tappet unchanged. In this embodiment, a tension spring 4 is installed between the plunger 21 and the valve bridge 14, that is, the tension spring 4 is installed in the hydraulic chamber 23. When the pressure in the hydraulic chamber 23 increases, the tension spring 4 can apply an elastic force to the plunger 21, so as to keep the length of the hydraulic tappet unchanged, thereby ensuring that the valve clearance remains unchanged.

[0043] The difference between this embodiment and the first embodiment is that as Figure 6 and Figure 7 shown, a compression spring 5 surrounding the tappet connecting portion and the cup seat 17 is installed between the rocker arm 11 and the valve bridge 14.

[0044] In this embodiment, at the moment of braking, the oil drain clearance reaches the maximum state, ensuring the oil drain effect.

[0045] Figure 8 It is a graph showing the relationship between the valve displacement and time or crankshaft angle during the working process. From the graph, the working state of the valve during normal engine operation and in-cylinder braking can be clearly seen.

[0046] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A hydraulic tappet assembly mechanism, where the hydraulic tappet is installed between the rocker arm and the valve bridge. This assembly mechanism includes a tappet connection part arranged at one end of the rocker arm. The tappet connection part is provided with a first oil passage communicating with the engine's oil oil circuit. An end of the tappet connection part facing the hydraulic tappet is installed with a bowl seat. The hydraulic tappet is installed on the valve bridge, and the bottom of the bowl seat abuts against the hydraulic tappet; it is characterized in that: A throttle orifice communicating the first oil passage with the hydraulic tappet oil inlet is provided at the bottom of the bowl seat.

2. The hydraulic tappet assembly mechanism according to claim 1, wherein: An installation hole is provided on the valve bridge, the hydraulic tappet is installed in the installation hole, and the valve bridge also serves as the tappet body of the hydraulic tappet.

3. The hydraulic tappet assembly mechanism according to claim 2, characterized in that: The hydraulic tappet includes a plunger and a pressure relief component. A hydraulic chamber opening towards the pressure relief component is provided in the plunger. The oil inlet of the hydraulic tappet is provided on the plunger. The oil inlet communicates the hydraulic chamber with the throttle orifice, and a check valve opening towards the hydraulic chamber is installed between the oil inlet and the hydraulic chamber. The pressure relief component includes a pressure relief passage communicating with the hydraulic chamber, and a pressure relief control valve is installed in the pressure relief passage.

4. The hydraulic tappet assembly mechanism according to claim 3, characterized in that: The pressure relief control valve includes a valve seat. The pressure relief passage includes a stepped hole communicating with the hydraulic chamber, and the valve seat is installed in the stepped hole. The pressure relief passage further includes a pressure relief hole communicating with the stepped hole. A sealing conical surface is provided between the stepped hole and the pressure relief hole. A valve core cooperating with the sealing conical surface is installed between the valve seat and the pressure relief hole, and a pressure relief spring for pushing the valve core away from the sealing conical surface is installed in the pressure relief hole.

5. The hydraulic tappet assembly mechanism according to claim 4, characterized in that: An oil passing gap communicating the hydraulic chamber with the pressure relief hole is provided between the valve seat and the stepped hole.

6. The hydraulic tappet assembly mechanism according to claim 4, characterized in that: An oil passing hole communicating the hydraulic chamber with the pressure relief hole is provided on the valve seat.

7. The hydraulic tappet assembly mechanism according to claim 4, wherein: The valve core is a spherical valve core.

8. The hydraulic tappet assembly mechanism according to claim 4, characterized in that: The pressure relief hole communicates with the oil sump.

9. The hydraulic tappet assembly mechanism according to any one of claims 3 to 8, characterized in that: A tension spring is installed in the hydraulic chamber. One end of the tension spring is fixedly connected to the inner wall of the hydraulic chamber, and the other end of the tension spring is fixedly connected to the inner wall of the installation hole.

10. The hydraulic tappet assembly mechanism according to any one of claims 3 to 8, characterized in that: A compression spring surrounding the tappet connecting portion and the bowl seat is installed between the rocker arm and the valve bridge.

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