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EP-4212707-B1 - ROCKER ARM MECHANISM AND ENGINE ASSEMBLY

EP4212707B1EP 4212707 B1EP4212707 B1EP 4212707B1EP-4212707-B1

Inventors

  • GUO, Shenggang
  • WANG, FEI
  • XU, CHENG

Dates

Publication Date
20260506
Application Date
20201207

Claims (8)

  1. A rocker arm mechanism, used as an intake mechanism (10) or an exhaust mechanism (20) of an engine assembly, and comprising: a rocker arm shaft (1); a rocker arm (2) rotatably disposed on the rocker arm shaft (1), wherein the rocker arm (2) is provided with a plunger chamber (21) and an oil supply passage (22), and the plunger chamber (21) is supplied with oil through the oil supply passage (22); a valve clearance adjuster (3) disposed on the rocker arm (2), wherein the valve clearance adjuster (3) comprises a hydraulic tappet (31) slidably disposed in the plunger chamber (21); a valve train (4) that comprises a valve bridge (41); the rocker arm mechanism is characterized by further comprising a control valve (5) configured to open or close the oil supply passage (22), wherein when the control valve (5) opens the oil supply passage (22), oil supplied by the oil supply passage (22) goes into the plunger chamber (21) and drives the hydraulic tappet (31) to extend out relative to the rocker arm (2) so that the hydraulic tappet (31) abuts against the valve bridge (41), and when the control valve (5) closes the oil supply passage (22), a position of the hydraulic tappet (31) relative to the rocker arm (2) remains unchanged; wherein the rocker arm (2) is further provided with a control chamber (23), and the oil supply passage (22) comprises a first oil passage (221) and a second oil passage (222) spaced apart on the rocker arm (2), wherein the first oil passage (221) and the second oil passage (222) are configured to communicate with the control chamber (23) separately, the first oil passage (221) is configured to communicate with the plunger chamber (21), and the second oil passage (222) is configured to be connected to an oil source; and the control valve (5) comprises a valve core (52) slidably located in the control chamber (23), wherein the valve core (52) is configured to make the first oil passage (221) and the second oil passage (222) connected or disconnected; wherein the control valve (5) further comprises a spring (51) disposed at a first end of the control chamber (23) and a pilot signal oil passage communicating with a second end of the control chamber (23); and the valve core (52) has a connection position for connection of the first oil passage (221) and the second oil passage (22), and a disconnection position for disconnection of the first oil passage (221) and the second oil passage (22), the spring (51) is configured to drive the valve core (52) to move towards the connection position, and the pilot signal oil passage is configured to drive the valve core (52) to move towards the disconnection position; wherein the pilot signal oil passage is configured to drive the valve core (52) to close the oil supply passage (22) when an engine brakes.
  2. The rocker arm mechanism according to claim 1, wherein the valve core (52) is provided with an oil guide slot (521), wherein the oil guide slot (521) is configured to be connected to the first oil passage (221) and the second oil passage (222) when the valve core (52) is at the connection position and be disconnected from the first oil passage (221) and the second oil passage (222) when the valve core (52) is at the disconnection position.
  3. The rocker arm mechanism according to claim 1, wherein the pilot signal oil passage comprises a control oil passage (55) for supplying oil to the control chamber (23) and a valve member configured to control the control oil passage (55) to open or close.
  4. The rocker arm mechanism according to claim 3, wherein the control oil passage (55) is a braking oil passage for supplying oil to a braking rocker arm (30), the valve member is a braking solenoid valve (58), and the braking rocker arm (30) is configured to brake the engine when the valve member is configured to open the braking oil passage.
  5. The rocker arm mechanism according to claim 3, wherein the control oil passage (55) is a dedicated oil passage for communicating with only the oil source and the control chamber (23), the valve member is a control solenoid valve (57), and the valve member is configured to control the control oil passage (55) to open when a rotational speed of the engine exceeds a set value.
  6. The rocker arm mechanism according to claim 3, wherein the control oil passage (55) is disposed on the rocker arm shaft (1), the pilot signal oil passage further comprises a connecting oil passage (56) disposed on the rocker arm (2), and the connecting oil passage (56) is configured to communicate with the control oil passage (55) and the control chamber (23).
  7. The rocker arm mechanism according to claim 1, wherein the control valve (5) further comprises a baffle (53) disposed in the control chamber (23) and a ring (54) disposed in the control chamber (23), the ring (54) and the spring (51) are disposed on two sides of the baffle (53), two ends of the spring (51) abut against the baffle (53) and the valve core (52) respectively, and the ring (54) engages with a chamber wall of the control chamber (23) and abuts against the baffle (53).
  8. An engine assembly, comprising an engine, wherein the engine comprises a cylinder assembly, wherein the cylinder assembly comprises a cylinder, an intake mechanism (10), an exhaust mechanism (20), and a braking rocker arm (30), wherein the exhaust mechanism (20) or the intake mechanism (10) is the rocker arm mechanism according to any one of claims 1 to 7; and the exhaust mechanism (20) is configured to control air exhaust, the intake mechanism (10) is configured to control air intake, and the braking rocker arm (30) is configured to abut against the valve bridge (41) of the exhaust mechanism (20) to brake the engine.

Description

TECHNICAL FIELD The present application relates to the technical field of engines, for example, a rocker arm mechanism and an engine assembly. BACKGROUND A large vehicle driven by a heavy-duty or medium-duty diesel engine is generally provided with an engine braking mechanism. When an engine brakes, a braking piston of a braking rocker arm extends out under the drive of braking oil and cooperates with a valve bridge, causing the valve bridge to incline. A large clearance is generated between an elephant foot on an exhaust rocker and the valve bridge so that the exhaust valve cannot be closed. In this manner, the compressed air in the cylinder is released, and work cannot be performed externally. However, in the related art, the use of an engine braking mechanism generally does not tolerate the situation where a hydraulic clearance adjuster is disposed on an exhaust rocker arm at the same time for clearance compensation. The hydraulic clearance adjuster is a hydraulic tappet for automatically adjusting the valve clearance of an engine as disclosed in the earlier patent application No. CN201010212462.1. Because when a clearance is generated, oil overfilling in a high-pressure chamber is caused. When braking stops, and an engine starts to fire and perform work, oil overfilling in the high-pressure chamber prevents oil in the high-pressure chamber from being discharged in time through a low-pressure chamber and the clearance between a plunger and a tappet body during a valve lift. Since oil is incompressible, the valve cannot be seated, leading to the situation where the valve is not tightly closed, and finally the valve is ablated or the valve collides with a piston. Further relevant technologies are discussed in the patent application publications: WO 99/32773 A1, GB 893 092 A, CN 106 382 140 A, CN 110 761 868 A, and CN 105 003 314 B. SUMMARY The present application provides a rocker arm mechanism and an engine assembly as defined in the attached claims 1 and 10 which are capable of dealing with the situation where the use of an engine braking mechanism generally does not tolerate the situation where a hydraulic clearance adjuster is disposed on an exhaust rocker arm at the same time for clearance compensation. Further improvements are provided in the dependent claims. The embodiments of the present application provide a rocker arm mechanism. The rocker arm mechanism includes a rocker arm shaft, a rocker arm, a valve clearance adjuster, a valve train, and a control valve. The rocker arm is rotatably disposed on the rocker arm shaft. The rocker arm is provided with a plunger chamber and an oil supply passage, and the plunger chamber is supplied with oil through the oil supply passage to supply oil. The valve clearance adjuster is disposed on the rocker arm. The valve clearance adjuster includes a hydraulic tappet slidably disposed in the plunger chamber. The valve train includes a valve bridge. The control valve is capable of opening or closing the oil supply passage. When the control valve opens the oil supply passage, the oil supplied by the oil supply passage goes into the plunger chamber and is capable of driving the hydraulic tappet to extend out relative to the rocker arm so that the hydraulic tappet abuts against the valve bridge. When the control valve closes the oil supply passage, the relative position between the hydraulic tappet and the rocker arm remains unchanged. The control valve closes the oil supply passage when an engine brakes. The embodiments of the present application provide an engine assembly. The engine assembly includes an engine. The engine includes a cylinder assembly. The cylinder assembly includes a cylinder, an intake mechanism, an exhaust mechanism, and a braking rocker arm. The exhaust mechanism is the rocker arm mechanism described above. The exhaust mechanism is configured to control exhaust air, the intake mechanism is configured to control intake air, and the braking rocker arm can abut against the valve bridge of the exhaust mechanism to brake the engine. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view one illustrating the structure of an intake mechanism, an exhaust mechanism, and a braking rocker arm in an embodiment of the present application.FIG. 2 is a view illustrating the structure of a rocker arm and a hydraulic clearance adjuster in an embodiment of the present application.FIG. 3 is an exploded view of a rocker arm, a control valve, and a hydraulic clearance adjuster in an embodiment of the present application.FIG. 4 is a sectional view of a rocker arm, a control valve, and a hydraulic clearance adjuster in an embodiment of the present application.FIG. 5 is sectional view one of a rocker arm mechanism in an embodiment of the present application (a valve core is in the connection position).FIG. 6 is sectional view two of a rocker arm mechanism in an embodiment of the present application (a valve core is at the disconnection position).FIG. 7 is view two illustrating