Engine rocker arm device

Abstract

An engine rocker arm device includes a rocker arm mounted on a rocker shaft, one end of the rocker arm adjacent to a cam of an engine, and the other end of the rocker arm adjacent to a valve of the engine. A connecting rod piston mechanism is provided in the rocker arm. The connecting rod piston mechanism includes a first connecting rod, a second connecting rod, and a connecting piston. One end of the first connecting rod is rotatably connected to one end of the second connecting rod. The other end of the first connecting rod is rotatably connected to the rocker arm. The other end of the second connecting rod is rotatably connected to one end of the connecting piston. The extension and retraction between the first connecting rod and the second connecting rod changes the gap between the other end of the connecting piston and the valve of the engine, thereby changing the motion imparted to the valve of the engine by the cam of the engine. The rocker arm device can be used to produce auxiliary valve motion of the engine, such as engine deactivation and engine braking.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of machinery, in particular to the field of engine valve drive, and more particularly to an engine rocker arm device. BACKGROUND

[0002] The conventional valve drive of vehicle engine is well known in the art, which has been applied for more than one hundred years. The conventional valve drive utilizes conventional valve actuators (including rockers) to control the movement of engine valves for the conventional firing operation of the engine. However, due to the additional requirements of engine fuel efficiency, exhaust emission and engine braking, more and more engines use variable valve drive.

[0003] Chinese patent CN104411925B (2018) discloses a system, method and device for controlling variable valve operation in an automotive engine, two cams have different lift profiles, two rockers are respectively placed on the two cams, and the different cam lift profiles are transmitted to the valves of the engine by locking the two rockers with a latch. The invention is a top cam acting on the central roller of the rocker, and its application is limited to passenger cars.

[0004] Chinese patent CN102373979B (2015) discloses a rocker arm device for engine deactivation, which includes an outer rocker arm and an inner rocker arm, and the inner and outer rocker arms are connected by a latch to transmit the movement of the cam to the valve. When the latch connection is disconnected, the movement of the cam is lost, the valve lift is zero, and the engine is deactivated. Similarly, the invention is a top cam acting on the central roller of the rocker, and its application is limited to passenger cars.

[0005] US patent US 5,537,976 (1996) discloses another device and method for two-stroke engine braking, which uses cam drive, hydraulic connection, high-speed solenoid valve and electronic control to achieve different valve movements and realize engine ignition or engine braking. Since the solenoid valve needs to be opened at least once in each cycle, the reliability and durability of the solenoid valve are particularly high. In addition to other problems of hydraulic drive, such as control of valve seating speed, cold start of the engine, etc., the invention has not been practically applied.

[0006] US patent US 6,293,248 (2001) discloses another device and method for two-stroke engine braking. In order to achieve two-stroke engine braking on a four-stroke engine, in addition to the need for four cams, four rockers must also be used: two exhaust rockers (one of which is used for braking) and two intake rockers (one of which is used for braking), which are complex in structure and control, and also use hydraulic drive to open the valves of the engine. SUMMARY

[0007] The present application aims to provide an engine rocker arm device to solve the problems of complicated structure and control, poor reliability and durability of hydraulic drive open valve and large application limitation in prior art.

[0008] The present application provides an engine rocker arm device, characterized in that it comprises a rocker arm arranged on a rocker arm shaft of an engine, one end of the rocker arm being close to a cam of the engine and the other end being close to a valve of the engine, a connecting rod piston mechanism being arranged in the rocker arm, the connecting rod piston mechanism comprising a first connecting rod, a second connecting rod and a connecting piston, one end of the first connecting rod and one end of the second connecting rod being rotatably connected, the other end of the first connecting rod being rotatably connected with the rocker arm, the other end of the second connecting rod being rotatably connected with one end of the connecting piston, the other end of the connecting piston facing the valve of the engine, the extension and contraction between the first connecting rod and the second connecting rod changing the gap between the connecting piston and the valve of the engine and changing the movement of the valve of the engine transmitted by the cam of the engine, the first connecting rod and the second connecting rod extending under the action of tension.

[0009] Further, the included angle between the first connecting rod and the second connecting rod is between greater than 0° and less than or equal to 180°, when the included angle is 180°, the first connecting rod and the second connecting rod are on the axis of the connecting piston, the connecting piston is fully extended, the gap between the connecting piston and the valve of the engine is the smallest, and the movement of the cam of the engine is transmitted to the valve of the engine to the maximum; when the included angle decreases, the connecting piston retracts, the gap between the connecting piston and the valve of the engine increases, and the movement of the cam of the engine transmitted to the valve of the engine decreases or is completely lost.

[0010] Further, it further comprises a fly-off prevention spring, the fly-off prevention spring pushing the rocker arm towards the cam of the engine.

[0011] Further, it further comprises a pre-tightening spring, the pre-tightening spring reducing the included angle between the first connecting rod and the second connecting rod and retracting the connecting piston.

[0012] Further, it further comprises a spring piston, the pre-tightening spring reducing the included angle between the first connecting rod and the second connecting rod and retracting the connecting piston by pushing the spring piston out.

[0013] Further, it further comprises a driving piston, the driving piston increasing the included angle between the first connecting rod and the second connecting rod and extending the connecting piston.

[0014] Further, the driving piston is driven by oil pressure to move towards the valve of the engine to increase the included angle between the first connecting rod and the second connecting rod and extend the connecting piston.

[0015] Furthermore, when the preload spring and the spring piston are included, the spring piston is pushed back by hydraulic pressure to overcome the force of the preload spring.

[0016] Furthermore, the driving piston and the connecting piston are the same piston.

[0017] Furthermore, it also includes a stop mechanism that limits the angle between the first link and the second link and the stroke of the connecting piston.

[0018] Furthermore, it also includes a guiding mechanism that restricts the movement of the first link, the second link, and the connecting piston in a plane.

[0019] Compared with existing technologies, the effects of this invention are positive and significant. The rocker arm device of this invention, through the extension and retraction of the connecting rod piston mechanism, separates or connects the engine valves to generate auxiliary valve movement for engine braking, etc. It has the advantages of simple and reliable structure, easy manufacturing and assembly, and wide application. In particular, the linkage mechanism has a large extension and retraction range (that is, a large variable range of the included angle between the first and second connecting rods), which can be applied to variable valve drive of engines with large lift, including engine cylinder deactivation that cancels the entire valve lift and engine braking during long strokes. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the retracted state of the connecting rod piston mechanism in an embodiment of the engine rocker arm device of the present invention.

[0021] Figure 2 This is a schematic diagram of the extended state of the connecting rod piston mechanism in an embodiment of the engine rocker arm device of the present invention. Detailed Implementation

[0022] Example:

[0023] Figure 1 and Figure 2An embodiment of the engine rocker arm apparatus of the present invention is shown in the figures. The rocker arm apparatus 200 includes a rocker arm 210 mounted on a rocker shaft 205 of an engine, one end of the rocker arm 210 is proximate to a cam 230 of the engine, and the other end is proximate to a valve 301 of the engine. The rocker arm 210 is provided with a link-piston mechanism 100, including a first link 152, a second link 154, and a connecting piston 160 mounted in a drive piston cavity 162 provided in the rocker arm 210, one end of the first link 152 and one end of the second link 154 are rotatably connected at 153, the other end of the first link 152 is rotatably connected at 151 to the rocker arm 210 (here shown as an adjustment screw 110, which is fastened to the rocker arm 210 by a nut 105 as part of the rocker arm 210), the other end of the second link 154 is rotatably connected at 156 to one end of the connecting piston 160, the other end of the connecting piston 160 faces (is directed towards) the valve 301 of the engine, the extension (stretching and contracting) between the first link 152 and the second link 154 changes the gap 234 between the connecting piston 160 and the valve 301 of the engine, and changes the motion of the valve 301 of the engine transmitted by the cam 230 of the engine. Here shown is a single valve 301, the present invention is also applicable to a dual valve, but a valve bridge can be added.

[0024] The angle between the extension of the first link 152 and the second link 154 of the link-piston mechanism 100 is between greater than 0° and less than or equal to 180°, the minimum angle can be controlled by a stop mechanism. When the angle is a straight angle (180°), the first link 152 and the second link 154 are on the axis of the connecting piston 160 (the axis of the direction of movement of the connecting piston 160), the connecting piston 160 is fully extended, the gap between the connecting piston 160 and the valve 301 of the engine is minimized, and the motion of the cam 230 of the engine is maximally transmitted to the valve 301 of the engine; when the angle decreases, the connecting piston 160 retracts, the gap between the connecting piston 160 and the valve 301 of the engine increases, and the motion of the cam 230 of the engine transmitted to the valve 301 of the engine decreases or is completely lost.

[0025] The embodiment also includes a guide mechanism, using pin connections and guides at one or more of the rotatable connections (151, 153, and 156), and guides using the side surfaces of the first link 152 and the second link 154 in cooperation with grooves in the rocker arm 210, so that the first link 152, the second link 154, and the connecting piston 160 move in a plane.

[0026] The embodiment also includes a fly-off prevention spring 198, which pushes the rocker arm 210 towards the cam 230 of the engine, preventing the gap between the rocker arm 210 and the valve 301 of the engine from being too large to cause impact.

[0027] The embodiment also includes a pre-tightening spring 136 that reduces the included angle between the first link 152 and the second link 154, retracts the connecting piston, and specifically, a spring piston 130 that is installed in a spring piston cavity 132 provided on the rocker arm 210, and the pre-tightening spring reduces the included angle between the first link and the second link by pushing the spring piston out, and in the embodiment, the spring piston can be pushed back by overcoming the force of the pre-tightening spring through oil pressure.

[0028] The embodiment also includes a driving piston that increases the included angle between the first link and the second link, and extends the connecting piston, and specifically, in the embodiment, the driving piston (provided in a matched piston cavity on the rocker arm 210) is driven by oil pressure to increase the included angle between the first link and the second link, and extend the connecting piston to the valve movement of the engine. In the embodiment, the driving piston is the same piston as the connecting piston.

[0029] The operation process of the embodiment is as follows. In the normal (or default) state, the control valve (not shown) is disconnected from the oil discharge, the oil pressure in the spring piston cavity 132 and the driving piston cavity 162 is zero, the pre-tightening spring 136 pushes the spring piston 130 out (to the right), and pushes the link piston mechanism 100 to the Figure 1 The retracted (contracted) position shown, the gap between the connecting piston 160 and the engine valve 301 is large, and the movement of the cam 230 to the valve 301 is reduced or eliminated.

[0030] When the engine needs cam movement (including engine braking), the control valve (not shown) is opened to supply oil, and the oil of the engine is supplied to the driving piston cavity 162 through the oil path (such as the axial oil hole 211 in the rocker shaft 205, and the oil passages 213 and 214 in the rocker arm 210), and the oil pressure pushes the driving piston 160 (in the embodiment, the connecting piston and the driving piston are the same piston) out (downward), and pulls down Figure 1 The link piston mechanism 100 in the retracted position Figure 2 The extended position shown, the gap between the connecting piston 160 and the engine valve 301 is small or eliminated, and the movement of the cam 230 is fully transmitted to the valve 301. Of course, oil can also be supplied to the spring piston cavity 132 and the driving piston cavity 162 at the same time, and the oil pressure overcomes the force of the pre-tightening spring to push the spring piston 130 back (to the left in the figure), and at the same time, the oil pressure pushes the driving piston 160 (the connecting piston and the driving piston are the same piston) out (downward in the figure), at this time, it is easier to pull down Figure 1 The link piston mechanism 100 in the retracted position Figure 2In the fully extended position shown, the clearance between the connecting piston 160 and the engine valve 301 is reduced or eliminated, and the motion of the cam 230 is transmitted entirely to the valve 301.

[0031] In the above embodiments, the rocker arm 210 is mounted on the engine rocker shaft 205. However, as an embodiment of the present application, the rocker arm can be mounted at other locations.

[0032] The above description should not be considered as limiting the scope of the present application, but merely as a representative embodiment thereof, from which numerous other variations can be derived. For example, the engine rocker arm assembly shown herein can be used not only in an overhead cam engine, but also in a push rod / push tube engine; not only for a single valve, but also for a dual valve; not only for driving an exhaust valve, but also for driving an intake valve; and the number, size, shape and phase of the cams can be varied.

[0033] The directions, such as up and down, are used for convenience of description, and should not be considered as limiting the arrangement of the mechanism of the present application. The same can be applied to left and right, or front and back, etc.

[0034] Therefore, the scope of the present application should not be determined by the above representative embodiments, but by the appended claims and their legal equivalents.

Claims

1. An engine rocker arm apparatus, characterized by, Comprising: a rocker arm, said rocker arm having a connecting rod piston mechanism disposed therein, said connecting rod piston mechanism comprising a first connecting rod, a second connecting rod and a connecting piston, one end of said first connecting rod and one end of said second connecting rod being rotatably connected, the other end of said first connecting rod being rotatably connected to said rocker arm, the other end of said second connecting rod being rotatably connected to one end of said connecting piston, the other end of said connecting piston facing an engine valve, the extension and contraction between said first connecting rod and said second connecting rod causing the gap between said connecting piston and said engine valve to change, changing the movement of the engine valve by the engine cam, said first connecting rod and said second connecting rod being extended under tension, wherein pin connections and guides are used at said rotatably connected locations, engine oil being supplied to a driving piston chamber through an oil passage, oil pressure driving said connecting piston disposed in said driving piston chamber, said connecting piston being pushed down by oil pressure, said connecting rod piston mechanism being pulled from a contracted position to an extended position.

2. The engine rocker arm apparatus of claim 1, wherein: The angle between said first connecting rod and said second connecting rod being between greater than 0° and less than or equal to 180°, when said angle is 180°, said first connecting rod and said second connecting rod being on the axis of said connecting piston, said connecting piston being fully extended, the gap between said connecting piston and said engine valve being the smallest, the movement of said engine valve by the engine cam being maximized; when said angle decreases, said connecting piston retracts, the gap between said connecting piston and said engine valve increases, the movement of said engine valve by the engine cam decreases or is completely lost.

3. The engine rocker arm apparatus of claim 1, wherein: Further comprising a fly-off prevention spring, said fly-off prevention spring pushing said rocker arm towards the engine cam.

4. The engine rocker arm apparatus of any one of claims 1-3, wherein: Further comprising a pre-tightening spring, said pre-tightening spring decreasing the angle between said first connecting rod and said second connecting rod, said connecting piston retracting.

5. The engine rocker arm apparatus of claim 4, wherein, Further comprising a spring piston, said pre-tightening spring decreasing the angle between said first connecting rod and said second connecting rod, said connecting piston retracting by pushing said spring piston out.

6. The engine rocker arm apparatus of claim 1, wherein: Further comprising a driving piston, said driving piston increasing the angle between said first connecting rod and said second connecting rod, said connecting piston extending.

7. The engine rocker arm apparatus of claim 6, wherein: Said driving piston being driven by oil pressure to move said engine valve, said driving piston increasing the angle between said first connecting rod and said second connecting rod, said connecting piston extending.

8. The engine rocker arm apparatus of claim 6, wherein: When a pre-tightening spring and a spring piston are included, said spring piston being pushed back by oil pressure to overcome the force of said pre-tightening spring.

9. The engine rocker arm apparatus of claim 6, wherein: Said driving piston being the same piston as said connecting piston.

10. The engine rocker arm apparatus of claim 1, wherein: Further comprising a stop mechanism, said stop mechanism limiting the size of the angle between said first connecting rod and said second connecting rod and the stroke of said connecting piston.

11. The engine rocker arm apparatus of claim 1, wherein: Further comprising a guide mechanism, said guide mechanism limiting the movement of said first connecting rod, said second connecting rod and connecting piston to a plane.

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