CN216841863U

CN216841863U - Rocker arm positioning device of engine

Info

Publication number: CN216841863U
Application number: CN202122507963.9U
Authority: CN
Inventors: 周鑫; 杨洲; 奚正
Original assignee: Shanghai Youshun Automobile Technology Co ltd
Current assignee: Shanghai Youshun Automobile Technology Co ltd
Priority date: 2021-10-18
Filing date: 2021-10-18
Publication date: 2022-06-28
Anticipated expiration: 2031-10-18

Abstract

A rocker arm positioning device of an engine comprises a stop mechanism and a biasing mechanism, wherein a baffle plate of the stop mechanism prevents a brake rocker arm from exceeding a second swinging position (maximum swinging angle) of the brake rocker arm, and a spring of the biasing mechanism biases the brake rocker arm above the baffle plate, so that a gap is generated between the brake rocker arm (roller) and a base circle of a brake cam, and the brake cam moves in a skipping mode. The utility model discloses a rocking arm positioner makes the braking rocking arm not have the motion during engine conventional ignition, but also can reduce the pretightning force of spring, has advantages such as highly low, small, light in weight, with low costs and durable reliable.

Description

Rocker arm positioning device of engine

Technical Field

The utility model relates to the field of machinary, especially, relate to engine, especially a rocking arm positioner of engine.

Background

Conventional valve actuation methods for vehicle engines are well known in the art and have been in use for over a hundred years. But due to additional demands on engine emissions and engine braking, more and more engines are required to add auxiliary valve movements, such as valve movements for exhaust gas recirculation and valve movements for engine braking, on the basis of conventional valve movements. Among them, the engine brake has become a necessary device for the engine of a heavy commercial vehicle.

The conventional engine brake is a box-type hydraulic drive mechanism which is arranged on the engine in a top-mounted mode. To install such an engine brake, a gasket is added between the cylinder and the valve cover, thus additionally increasing the height, weight, and cost of the engine. These problems are caused by the engine braking system being considered as an additional accessory to the engine, rather than being an integral part or piece of the engine.

Integrating the engine braking system within existing components of the engine can reduce the height, weight, and cost of the engine. One dedicated rocker arm braking device is disclosed by the american Cummins Engine corporation, U.S. patent No. 5626116 (1997). A hydraulic brake driving mechanism is arranged in the special brake rocker arm and comprises a hydraulic piston. When engine braking is not required, the hydraulic piston in the special braking rocker arm is in a retracted position, the special braking rocker arm is separated from the valve, and the motion of the special braking cam is skipped (lost); when engine braking is required, the hydraulic piston in the dedicated braking rocker arm is in an extended position and the dedicated braking rocker arm transmits the motion of the dedicated braking cam to one of the two exhaust valves, producing engine braking.

Chinese patent CN101338691 discloses an engine brake with a special braking rocker arm. The engine brake actuator includes a brake piston slidably disposed within a valve bridge and movable between a non-operative position and an operative position. Typically, when engine braking is not required, the brake piston is biased by a spring into a non-operating position and provides a large clearance with the brake rocker arm or the lash adjustment screw so that the brake boss on the brake cam can be overridden. In order to prevent the flying off or the collision due to the gap, an engine brake positioning mechanism must be provided. In this patent and other prior art, the detent mechanism utilizes a spring to bias the brake rocker arm against the cam, thus requiring a special spring bracket on the engine, occupying a large space, being inconvenient to install, and being costly. In addition, the brake rocker arm produces unwanted motion during engine firing operations.

Disclosure of Invention

An object of the utility model is to provide a rocker arm positioner of engine, this kind of rocker arm positioner need solve among the prior art engine brake positioning mechanism need special spring bracket, occupation space big, the installation is inconvenient and with high costs to and produce the technical problem of useless motion during engine ignition function.

The utility model discloses a this kind of rocking arm positioner, its rocking arm is swung between primary importance and second place by the drive of engine cam primary importance, the rocking arm links to each other with the base circle of engine cam secondary place, the rocking arm links to each other its characterized in that with the top of engine cam: the rocker arm positioning device comprises a stop mechanism and a biasing mechanism, the stop mechanism prevents the rocker arm from swinging beyond the second position, and the biasing mechanism biases the rocker arm at the second position.

Further, the rocker arm is an engine brake rocker arm, and the cam is an engine brake cam.

Further, the stop mechanism comprises a baffle plate, and the baffle plate blocks the rocker arm at the second position.

Further, the baffle has elasticity, and the rocking arm is allowed to have slight swing in the second position.

Further, the biasing mechanism includes a spring that biases the rocker arm in the second position to create a lash between the rocker arm and the base circle of the cam, the lash being no less than a lift of the cam.

Further, the spring comprises a leaf spring.

Further, the spring comprises a coil spring.

Furthermore, the device also comprises a clearance adjusting mechanism, and the clearance adjusting mechanism is used for setting a clearance between the stop mechanism and the rocker arm.

Compared with the prior art, the utility model has positive and obvious effect. The utility model discloses a rocking arm positioning mechanism will brake the rocking arm and fix a position the final position (the second position of the biggest pivot angle) after the rocking arm swing, and parts (do not receive the drive of brake cam) with the brake cam, and during the conventional ignition of engine, the brake rocking arm does not have any motion, and reliability and durability strengthen greatly. Furthermore, the utility model discloses a rocking arm positioning mechanism occupation space is little (especially reduce the height), compact structure, simple to operate, and is with low costs.

Drawings

Fig. 1 is a schematic diagram of an embodiment of the rocker arm positioning device of the present invention with the brake in the "on" position and the brake rocker arm in the first position.

Fig. 2 is a schematic view of an embodiment of the rocker arm positioning device of the present invention with the brake in the "off" position and the brake rocker arm in the second position.

Detailed Description

Example (b):

as shown in fig. 1 and 2, the engine braking rocker arm 210 (which may be a rocker arm of another use or form) is arranged in a swinging manner on a rocker shaft 205 (an intake rocker arm and an exhaust rocker arm are arranged side by side with the braking rocker arm on the rocker shaft, not shown here), and the braking rocker arm 210 has a braking cam 230 at one end (here a roller 235, which may also be a push rod mechanism) and a braking cam 230 at the other end above a valve 301 of the engine (a valve bridge 400 or even a valve stem cap is arranged above a valve stem of the valve 301, and the exhaust rocker arm acts on the center of the valve bridge). The brake rocker arm 210 is driven by the brake cam 230 to oscillate between a first position (fig. 1), in which the brake rocker arm 210 is connected to the base circle 229 of the brake cam 230, and a second position (fig. 2), in which the brake rocker arm 210 is connected to the tip of the brake cam 230 (the gap 212 between the brake rocker arm 210 (roller 235) and the base circle 229 is equal to the height of the brake boss 231). The utility model discloses a rocking arm positioner is including ending a position mechanism and biasing mechanism, and wherein end a position mechanism and prevent the swing of rocking arm to surmount the second position, and biasing mechanism is with the rocking arm biasing in the second position.

The stop mechanism of this embodiment is a stop plate 141, one end of the stop plate 141 is fixed to the engine body (which may be the rocker shaft 205 or any component that does not move relative to the engine body), and the other end stops the braking rocker 210 in the second position (fig. 2). The biasing mechanism of this embodiment is a spring 146 (which may be a leaf spring or other type of spring), one end of the spring 146 being fixed to the engine block (which may be the rocker shaft 205 or any component that does not move relative to the engine block) and the other end biasing the brake rocker 210 to the second position. Since the spring 146 is substantially less resilient than the stop 141, the spring presses the brake rocker 210 against the stop 141 in the second position as shown in fig. 2. Although the rigidity of the flap 141 is large (deformation is small), the braking rocker 210 may slightly swing with the deformation of the flap 141 under the pressure of the spring 146, which is allowable. Of course, a clearance adjustment mechanism may be provided between the shutter 141 and the rocker arm 210, and the clearance between the shutter 141 (stopper mechanism) and the rocker arm 210 may be accurately set to accurately position the rocker arm 210.

The working process of the engine brake with the brake rocker arm positioning device of the embodiment is as follows: during normal firing operation (engine braking is not required), the engine brake control mechanism (not shown) is disconnected from oil discharge, the brake piston 160 of the brake mechanism 100 is in an upward retracted state (fig. 2), the spring 146 of the biasing mechanism presses the brake rocker 210 against the stop 141 of the positioning mechanism, and a gap 212 is generated between the brake rocker 210 (roller 235) and the base circle 229 of the brake cam 230, wherein the gap 212 is not smaller than the lift of the brake cam (the height of the brake boss 231), so that the motion of the brake cam 230 is skipped and cannot be transmitted to the engine valve 301. It is apparent that the brake rocker arm 210 is at rest (no relative motion with the engine block) throughout the ignition operation. The valve motion for engine firing is generated by a conventional valve actuation mechanism (not shown) and is not affected by the engine brake.

When engine braking is required, the engine brake control mechanism (not shown) turns on the oil supply, and the brake piston 160 of the brake mechanism 100 is in a downwardly extended state (fig. 1). The brake rocker arm 210 rotates counter-clockwise against the force of the spring 146, away from the stop 141 of the detent mechanism, creating a gap 234, and the roller 235 is connected to the base circle 229 of the brake cam 230. The motion of the brake cam 230 is transferred to the engine valve 301 through the rocker arm 210 and the brake mechanism 100 in the operating position within the rocker arm to produce the valve motion required for engine braking. Of course, the engine firing valve motion produced by a conventional valve actuation mechanism (not shown) is still present, without interfering with the braking valve motion.

The embodiments of the present invention are illustrative, but not restrictive, of the present invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope and spirit of the invention. For example, some portion of the functionality illustrated or described for one particular mechanism may be used for another particular mechanism to yield a new mechanism. The position and attachment of the flapper and spring in the embodiment may vary, for example, flapper 141 may move from below the right side of rocker arm 210 to above the left side of rocker arm 210. Further, the braking mechanism 100 within the rocker arm 210 may also be varied. Also, the rocker arm may be other types of rocker arms besides a brake rocker arm, such as an EGR rocker arm. Thus, the present invention is intended to embrace all such modifications and variations as fall within the scope of the appended claims or equivalents thereof.

Claims

1. A rocker arm positioning device of an engine, wherein the rocker arm is driven by an engine cam to swing between a first position, in which the rocker arm is connected to a base circle of the engine cam, and a second position, in which the rocker arm is connected to a tip end of the engine cam, characterized in that: the rocker arm positioning device comprises a stop mechanism and a biasing mechanism, the stop mechanism prevents the rocker arm from swinging beyond the second position, and the biasing mechanism biases the rocker arm at the second position.

2. The rocker arm positioning device of claim 1, wherein: the rocker arm is an engine brake rocker arm, and the cam is an engine brake cam.

3. The rocker arm positioning device of claim 1, wherein: the stop mechanism comprises a baffle plate, and the baffle plate blocks the rocker arm at the second position.

4. The rocker arm positioning apparatus of claim 3, wherein: the baffle has elasticity, and allows the rocker arm to slightly swing at the second position.

5. The rocker arm positioning device of claim 1, wherein: the biasing mechanism comprises a spring, and the spring biases the rocker arm to the second position to generate a clearance between the rocker arm and a base circle of the cam, wherein the clearance is not smaller than the lift of the cam.

6. The rocker arm positioning device of claim 5, wherein: the spring comprises a leaf spring.

7. The rocker arm positioning device of claim 5, wherein: the spring comprises a coil spring.

8. The rocker arm positioning device of claim 1, wherein: the rocker arm is characterized by further comprising a gap adjusting mechanism, and the gap adjusting mechanism is used for setting a gap between the stop mechanism and the rocker arm.