CN114909198A

CN114909198A - Rocker arm device of engine

Info

Publication number: CN114909198A
Application number: CN202110184057.1A
Authority: CN
Inventors: 杨洲; 奚正; 朱汝杰; 邢宝亮
Original assignee: Shanghai Youshun Automobile Technology Co ltd
Current assignee: Shanghai Youshun Automobile Technology Co ltd
Priority date: 2021-02-10
Filing date: 2021-02-10
Publication date: 2022-08-16

Abstract

The rocker arm device for engine includes one rocker arm on the rocker shaft, one end of the rocker arm is near the cam of the engine, the other end of the rocker arm is near the valve of the engine, and the rocker arm has one link rod-piston mechanism comprising one first link rod, one second link rod and one connecting piston. The rocker arm apparatus of the present invention may be used to generate auxiliary valve motion for an engine, such as engine deactivation and engine braking.

Description

Rocker arm device of engine

Technical Field

The invention relates to the field of machinery, in particular to the field of engine valve driving, and particularly relates to an engine rocker arm device.

Background

Conventional valve actuation for vehicle engines is well known in the art and has been in use for over a hundred years. Conventional valve actuation utilizes a conventional valve actuator (including a rocker arm) to control the motion of an engine valve for conventional spark operation of the engine. But more and more engines employ variable valve actuation due to additional demands on engine fuel efficiency, exhaust emissions and engine braking.

Chinese invention patent CN104411925B (2018) discloses a system, method and apparatus for controlling variable valve operation in an automotive engine, two cams having different lift profiles, two rocker arms respectively straddling the two cams, the two rocker arms being locked by latches to transfer the different cam lift profiles to the valves of the engine. The invention is that the overhead cam acts on a roller at the center of a rocker arm, and the application of the overhead cam is limited to passenger cars.

Chinese invention patent CN102373979B (2015) discloses a rocker arm device for engine cylinder closing, comprising an outer rocker arm and an inner rocker arm, wherein the inner and outer rocker arms are connected by a latch to transfer the motion of a cam to a valve. When the latch connection is disconnected, the motion of the cam is lost, the valve lift is zero, and the engine is deactivated. Also, the invention is that the overhead cam acts on the roller in the center of the rocker arm, and the application is limited to passenger cars.

U.S. Pat. No. 5,537,976(1996) discloses another two-stroke engine braking apparatus and method, which uses cam actuation, hydraulic connections, high speed solenoid valves and electronic control to achieve different valve motions, to achieve engine ignition or engine braking. Since the solenoid valve needs to be opened at least once during each cycle, there are particularly high demands on the reliability and durability of the solenoid valve. Coupled with other problems with hydraulic actuation such as control of valve seating velocity, cold start of the engine, etc., the invention has not been practical.

Still another two-stroke engine braking apparatus and method is disclosed in U.S. Pat. No. 6,293,248 (2001). In order to achieve two-stroke engine braking on a four-stroke engine, in addition to requiring four cams, four rocker arms must be employed: two exhaust rocker arms (one of which is used for braking) and two intake rocker arms (one of which is used for braking) are complex in structure and control, and a valve of the engine is opened by adopting hydraulic drive.

Disclosure of Invention

The invention aims to provide an engine rocker arm device, which aims to solve the problems that the structure and control are complex, the reliability and durability of a hydraulically-driven opening valve are poor, the application limitation is large and the like in the prior art.

The invention provides an engine rocker arm device, which is characterized by comprising: the rocker arm is arranged on a rocker shaft of the engine, one end of the rocker arm is close to a cam of the engine, the other end of the rocker arm is close to a valve of the engine, a connecting rod piston mechanism is arranged in the rocker arm and comprises a first connecting rod, a second connecting rod and a connecting piston, one end of the first connecting rod is rotatably connected with one end of the second connecting rod, the other end of the first connecting rod is rotatably connected with the rocker arm, the other end of the second connecting rod is rotatably connected with one end of the connecting piston, the other end of the connecting piston faces the valve of the engine, the expansion and contraction between the first connecting rod and the second connecting rod enable a gap between the connecting piston and the valve of the engine to be changed, the motion transmitted to the valve of the engine by the cam of the engine is changed, and the first connecting rod and the second connecting rod are expanded under the action of pulling force.

Furthermore, the telescopic included angle between the first connecting rod and the second connecting rod is more than 0 degree and less than or equal to 180 degrees, when the included angle is 180 degrees, the first connecting rod and the second connecting rod are arranged on the axis of the connecting piston, the connecting piston completely extends out, the gap between the connecting piston and the engine valve is minimum, and the motion of the engine cam is transmitted to the engine valve to the maximum extent; when the angle is reduced, the connecting piston retracts, the clearance between the connecting piston and the engine valve increases, and the motion transmitted by the engine cam to the engine valve is reduced or lost completely.

Furthermore, the engine further comprises an anti-flying off spring which pushes the rocker arm to a cam of the engine.

Furthermore, the connecting device also comprises a pre-tightening spring, wherein the pre-tightening spring enables an included angle between the first connecting rod and the second connecting rod to be reduced and the connecting piston to retract.

And the pre-tightening spring is used for reducing an included angle between the first connecting rod and the second connecting rod and retracting the connecting piston by pushing out the spring piston.

Furthermore, the device also comprises a driving piston, wherein the driving piston increases an included angle between the first connecting rod and the second connecting rod and is connected with the piston to extend out.

Further, the drive piston is hydraulically driven to move toward the valve of the engine, so that the included angle between the first connecting rod and the second connecting rod is increased, and the connecting piston is extended.

Further, when the pre-tightening spring and the spring piston are included, the spring piston is also pushed back against the force of the pre-tightening spring by oil pressure.

Furthermore, the driving piston and the connecting piston are the same piston.

Furthermore, the connecting device also comprises a stop mechanism, and the stop mechanism limits the size of an included angle between the first connecting rod and the second connecting rod and the stroke of the connecting piston.

Furthermore, the connecting rod device further comprises a guide mechanism, and the guide mechanism limits the first connecting rod, the second connecting rod and the connecting piston to move in a plane.

Compared with the prior art, the invention has positive and obvious effect. The rocker arm device of the invention generates the auxiliary valve motion of the engine by the expansion and contraction of the connecting rod piston mechanism and separating or connecting the valve of the engine, is used for engine braking and the like, has the advantages of simple and reliable structure, easy manufacture and assembly, wide application and the like, particularly has large expansion and contraction amount of the connecting rod mechanism (namely the variable range of the included angle between the first connecting rod and the second connecting rod is large), and can be applied to the variable valve driving of the engine with large lift, including the engine cylinder deactivation and the engine braking with large stroke without the whole valve lift.

Drawings

FIG. 1 is a schematic illustration of a rod piston mechanism in a retracted state in an embodiment of an engine rocker arm apparatus of the present invention.

FIG. 2 is a schematic illustration of an extended state of a connecting rod-piston mechanism in an embodiment of an engine rocker arm apparatus of the present invention.

Detailed Description

The embodiment is as follows:

fig. 1 and 2 are used to describe an embodiment of an engine rocker arm apparatus of the present invention. The rocker arm arrangement 200 in the figure comprises a rocker arm 210, the rocker arm 210 being arranged on a rocker shaft 205 of the engine, the rocker arm 210 being close to a cam 230 of the engine at one end and close to a valve 301 of the engine at the other end. The rocker arm 210 is provided with a connecting rod piston mechanism 100, comprising a first link 152, a second connecting rod 154 and a connecting piston 160 (the connecting piston 160 is mounted in a drive piston chamber 162 provided in the rocker arm 210), one end of the first connecting rod 152 and one end of the second connecting rod 154 are rotatably connected at 153, the other end of the first connecting rod 152 is rotatably connected at 151 to the rocker arm 210 (here shown as an adjusting screw 110 secured to the rocker arm 210 by a nut 105 as part of the rocker arm 210), the other end of the second connecting rod 154 is rotatably connected at 156 to one end of the connecting piston 160, the other end of the connecting piston 160 faces (faces) a valve 301 of the engine, and extension and retraction (extension and retraction) between the first connecting rod 152 and the second connecting rod 154 causes a change in a clearance 234 between the connecting piston 160 and the engine valve 301, changing the motion transmitted by the engine cam 230 to the engine valve 301. Here, a single valve 301 is shown, the invention is equally applicable to dual valves, although a valve bridge may be added.

The angle of the first link 152 and the second link 154 of the rod-and-piston mechanism 100 is greater than 0 ° to less than or equal to 180 °, and the minimum angle can be controlled by a stop mechanism. When the included angle is a straight angle (180 °), the first connecting rod 152 and the second connecting rod 154 are on the axis connecting the pistons 160 (the axis connecting the moving directions of the pistons 160), the connecting pistons 160 are fully extended, the clearance between the connecting pistons 160 and the engine valve 301 is minimum, and the motion of the engine cam 230 is maximally transmitted to the engine valve 301; as the angle decreases, the connecting piston 160 retracts, the clearance to the engine valve 301 increases, and the motion imparted by the engine cam 230 to the engine valve 301 is reduced or lost altogether.

The present embodiment further includes a guide mechanism, which is pinned and guided at one or more of the pivot connections (151, 153, and 156) and may also be guided by the sides of the upper and second links mating with slots in the rocker arms, such that the first link 152, the second link 154, and the connecting piston 160 move in a plane.

The present embodiment also includes a fly-off prevention spring 198 that urges the rocker arm 210 toward the engine's cam 230, preventing too large a clearance between the rocker arm 210 and the engine valve 301 from creating a shock.

The embodiment further comprises a pre-tightening spring 136, the pre-tightening spring 136 enables an included angle between the first connecting rod 152 and the second connecting rod 154 to be reduced and the connecting piston to retract, and specifically, the pre-tightening spring 130 further comprises a spring piston 130, the spring piston 130 is installed in a spring piston cavity 132 arranged on the rocker arm 210, the pre-tightening spring enables the included angle between the first connecting rod and the second connecting rod to be reduced and the connecting piston to retract by pushing the spring piston out, and in the embodiment, the pre-tightening spring can overcome the acting force of the pre-tightening spring through oil pressure to push the spring piston back.

The present embodiment further includes a driving piston, which increases an included angle between the first connecting rod and the second connecting rod and extends the connecting piston, specifically, in the present embodiment, the driving piston (disposed in a matching piston cavity on the rocker arm 210) is driven by oil pressure to move towards the valve of the engine, so that the included angle between the first connecting rod and the second connecting rod is increased and the connecting piston extends. In this embodiment, the driving piston and the connecting piston are the same piston.

The operation of this embodiment is as follows. In the normal (or default) state, the control valve (not shown) is de-oiled, the oil pressure in the spring piston chamber 132 and the drive piston chamber 162 is zero, the preload spring 136 pushes the spring piston 130 out (to the right), pushing the connecting rod-piston mechanism 100 to the retracted (contracted) position shown in fig. 1, the clearance between the connecting piston 160 and the engine valve 301 is increased, and the motion imparted to the valve 301 by the cam 230 is reduced or eliminated.

When the engine needs cam motion (including engine braking), the control valve (not shown) is opened to supply oil, the engine oil of the engine is supplied to the driving piston cavity 162 through oil passages (such as the axial oil hole 211 in the rocker shaft 205 and the

oil passages

213 and 214 in the rocker arm 210), the oil pressure pushes out (downwards) the driving piston 160 (in this embodiment, the connecting piston and the driving piston are the same piston), the connecting rod piston mechanism 100 in the retracted position in fig. 1 is pulled over to the extended position shown in fig. 2, the clearance between the connecting piston 160 and the engine valve 301 is reduced or eliminated, and the motion of the cam 230 is completely transmitted to the valve 301. Of course, it is also possible to supply oil to both the spring piston chamber 132 and the drive piston chamber 162, and the oil pressure overcomes the biasing force of the biasing spring to push the spring piston 130 back (to the left in the figure) and push the drive piston 160 (the connecting piston and the drive piston are the same piston) out (to the bottom in the figure), and at this time, it is easier to pull the rod piston mechanism 100 in the retracted position in fig. 1 to the fully extended position shown in fig. 2, and the clearance between the connecting piston 160 and the engine valve 301 is reduced or eliminated, and the entire motion of the cam 230 is transmitted to the valve 301.

While the rocker arm 210 is mounted on the rocker shaft 205 of the engine in the above embodiments, the rocker arm may be mounted in other positions as well as the invention.

The above description should not be taken as limiting the scope of the invention, but as being a specific exemplification of the invention, many other variations are possible. For example, the engine rocker arm arrangements shown herein may be used not only in overhead cam engines, but also in push rod/push tube engines; not only can open a single valve, but also can open double valves; the valve can be used for driving an exhaust valve and an intake valve; the number, size, shape, phase, etc. of the lobes included in the cam may vary.

The directions of the present invention, such as up and down, are for convenience of description, and should not be construed as limiting the arrangement of the mechanism of the present invention, and can be equally applied to left and right, or front and rear, etc.

The scope of the invention should, therefore, be determined not with reference to the above detailed description, but instead should be determined with reference to the appended claims along with their legal equivalents.

Claims

1. An engine rocker arm apparatus, comprising: the rocker arm is internally provided with a connecting rod piston mechanism, the connecting rod piston mechanism comprises a first connecting rod, a second connecting rod and a connecting piston, one end of the first connecting rod is rotatably connected with one end of the second connecting rod, the other end of the first connecting rod is rotatably connected with the rocker arm, the other end of the second connecting rod is rotatably connected with one end of the connecting piston, the other end of the connecting piston faces to an engine valve, the extension and the contraction between the first connecting rod and the second connecting rod change a gap between the connecting piston and the engine valve, the motion transmitted to the engine valve by an engine cam is changed, and the first connecting rod and the second connecting rod extend under the action of pulling force.

2. The engine rocker arm apparatus of claim 1, wherein: the telescopic included angle between the first connecting rod and the second connecting rod is more than 0 degree and less than or equal to 180 degrees, when the included angle is 180 degrees, the first connecting rod and the second connecting rod are arranged on the axis of the connecting piston, the connecting piston extends out completely, the clearance between the connecting piston and the engine valve is minimum, and the motion of the engine cam is transmitted to the engine valve to the maximum extent; when the included angle is reduced, the connecting piston retracts, the clearance between the connecting piston and the engine valve is increased, and the motion transmitted to the engine valve by the engine cam is reduced or completely lost.

3. The engine rocker arm apparatus of claim 1, wherein: the anti-flying-off device further comprises an anti-flying-off spring, and the anti-flying-off spring pushes the rocker arm to a cam of the engine.

4. The engine rocker arm apparatus of any of claims 1-3, wherein: the connecting piston is characterized by further comprising a pre-tightening spring, and the pre-tightening spring enables an included angle between the first connecting rod and the second connecting rod to be reduced and the connecting piston to retract.

5. The engine rocker arm apparatus of claim 4, further comprising a spring piston, wherein the preloaded spring retracts the connecting piston by urging the spring piston out of a position that reduces the angle between the first and second connecting rods.

6. The engine rocker arm apparatus of any of claims 1-4, wherein: the connecting rod device further comprises a driving piston, and the driving piston enables an included angle between the first connecting rod and the second connecting rod to be increased and the connecting piston to extend out.

7. The engine rocker arm apparatus of claim 5, wherein: the drive piston is driven by oil pressure to move towards the valve of the engine, so that the included angle between the first connecting rod and the second connecting rod is increased, and the connecting piston extends out.

8. The engine rocker arm apparatus of claim 6, wherein: when the pre-tightening spring and the spring piston are included, the spring piston is also pushed back against the acting force of the pre-tightening spring by oil pressure.

9. The engine rocker arm apparatus of claim 6, wherein: the driving piston and the connecting piston are the same piston.

10. The engine rocker arm apparatus of claim 1, wherein: the stop mechanism limits the size of an included angle between the first connecting rod and the second connecting rod and the stroke of the connecting piston.

11. The engine rocker arm apparatus of claim 1, wherein: the connecting device also comprises a guide mechanism which limits the first connecting rod, the second connecting rod and the connecting piston to move in a plane.