Positioning mechanism of engine brake rocker arm

Abstract

A positioning mechanism of an engine brake rocker arm comprises a positioning bolt and a positioning spring, one end of the positioning bolt is fixedly connected with a rocker arm shaft, one end of the positioning spring abuts against the other end of the positioning bolt, and the other end of the positioning spring movably abuts against the rocker arm. And the positioning spring enables motion resistance to be generated between the rocker arm and the rocker arm shaft. The rocker arm does not move in the non-engine braking operation period, flying-off, friction and oil consumption of the mechanism are eliminated, the use frequency is greatly reduced, and the whole mechanism does not occupy space (especially not heightened) and not weighted, and is compact in structure, convenient to install, low in cost, durable and reliable.

Description

TECHNICAL FIELD

[0001] The present embodiment relates to the field of machinery, and in particular to an engine, and more particularly to a positioning mechanism for an engine brake rocker arm. BACKGROUND

[0002] US Patent No. 5626116 (1997) discloses a dedicated brake rocker arm. The dedicated brake rocker arm houses a hydraulic brake actuation mechanism, including a hydraulic piston. When engine braking is not required, the hydraulic piston in the dedicated brake rocker arm is in a retracted position, the dedicated brake rocker arm is separated from the valve, the movement of the dedicated brake cam is skipped (lost), and no brake valve movement is generated; when engine braking is required, the hydraulic piston in the dedicated rocker arm is in an extended position, the dedicated rocker arm transmits the movement of the dedicated brake cam to one of the two exhaust valves, generating engine brake valve movement.

[0003] US Patent No. 5,975,251 (1999) discloses a locking device for a dedicated brake rocker arm. When not braking (firing), the dedicated brake rocker arm is locked on the rocker shaft, both ends are suspended, neither touching the brake cam nor hitting the brake valve. This locking device is used on the dedicated brake rocker arm of Cummins ISX engine, but it is found to be unreliable, the rocker arm will sway and impact on the rocker shaft, causing engine damage. Obviously, during braking, the rocker arm can rotate freely on the rocker shaft, cannot be positioned, and is likely to collide with the cam or valve, with poor reliability.

[0004] Existing dedicated brake rocker arms are all biased on the cam by a spring, driven by the cam. For example, the rocker arm in Chinese Utility Model Patent No. CN201666172U is biased on the brake cam by a spring installed between the bracket and the pressing plate, so a special spring bracket needs to be added to the engine, occupying a large space, and being inconvenient to install, and high in cost. Since the rocker arm is always driven by the brake cam (moving during firing and braking), the rocker arm generates useless movement during engine firing operation, greatly increasing the use frequency and wear and impact of the rocker arm. In addition, the spring must have a large pre-tightening force to maintain the engine brake rocker arm in contact with the cam (not flying off) during rotation of the cam shaft. SUMMARY

[0005] The engine brake rocker arm positioning mechanism of the embodiment aims to solve the technical problems of poor reliability of the locking mechanism of the engine brake rocker arm, the rocker arm requiring a large pre-tightening force spring and a special bracket, large space occupation, inconvenient installation, high cost, useless movement of the rocker arm during engine ignition operation, increased use frequency, wear and tear and oil consumption.

[0006] In a first aspect, the utility model provides an engine brake rocker arm positioning mechanism, the rocker arm is rotatably arranged on the rocker shaft of the engine, the positioning mechanism exerts force between the rocker arm and the rocker shaft to increase the movement resistance of the rocker arm on the rocker shaft and keep the rocker arm in two non-collision positions on the rocker shaft, in the two non-collision positions, one end of the rocker arm avoids the drive of the cam of the engine and the other end of the rocker arm avoids the action with the valve of the engine,

[0007] The positioning mechanism comprises a positioning bolt and a positioning spring, one end of the positioning bolt is fixedly connected with the rocker shaft, one end of the positioning spring is in abutment with the other end of the positioning bolt, and the other end of the positioning spring is movably in abutment with the rocker arm, and the positioning spring exerts force between the rocker arm and the rocker shaft.

[0008] Optionally, one end of the positioning spring is in contact with the other end of the positioning bolt.

[0009] Optionally, the rocker arm comprises a positioning stepped hole arranged along the radial direction of the rocker shaft, the positioning stepped hole comprises two positioning grooves of different sizes, the smaller positioning groove is arranged close to the rocker shaft, a stepped surface is formed between the two positioning grooves, the positioning bolt is arranged in the positioning stepped hole and is fixedly connected with the rocker shaft, and the other end of the positioning spring is movably in abutment with the stepped surface.

[0010] Optionally, the positioning stepped hole is provided with a clearance space for avoiding the positioning bolt, and when the rocker arm rotates around the rocker shaft, the positioning bolt rotates relatively in the clearance space.

[0011] Optionally, the smaller positioning groove has a predetermined length, the length of the clearance space is formed on the predetermined length, when the rocker arm rotates around the rocker shaft, the predetermined length determines the distance of the relative rotation of the positioning bolt in the smaller positioning groove, and the rotation angle of the rocker arm on the rocker shaft is controlled.

[0012] Optionally, when the rocker arm rotates around the rocker shaft, the other end of the positioning spring moves on the stepped surface.

[0013] Optionally, the positioning spring is sleeved outside the positioning bolt and located in the large positioning groove.

[0014] Optionally, the width of the large positioning groove is slightly larger than the outer diameter of the positioning spring, and the width of the small positioning groove is slightly larger than the outer diameter of the positioning bolt.

[0015] Optionally, the positioning mechanism further comprises a gasket, the gasket is arranged on the stepped surface between the two positioning grooves and sleeved outside the positioning bolt, and the other end of the positioning spring is arranged on the upper surface of the gasket.

[0016] Optionally, when the rocker arm rotates around the rocker shaft, the other end of the positioning spring moves together with the gasket on the stepped surface.

[0017] Optionally, the positioning bolt is a flange bolt, and one end of the positioning spring abuts against the flange plate of the flange bolt.

[0018] Optionally, one end of the positioning spring abuts against the flange plate of the flange bolt.

[0019] Optionally, the rocker shaft comprises a threaded hole arranged in the radial direction of the rocker shaft, and the positioning bolt is fixed in the threaded hole on the rocker shaft.

[0020] Compared with the prior art, the effect of the embodiment is positive and obvious. The rocker arm is positioned in a position not colliding with the brake cam and the engine valve, is not driven by the brake cam, has no movement in the non-braking (ignition) state of the engine, reduces wear and oil consumption, and enhances reliability and durability. In addition, the positioning mechanism of the embodiment does not occupy space (especially does not increase height), does not increase weight, has a compact structure, is easy to install, has good reliability, and has low cost. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic view of the positioning mechanism of the engine brake rocker arm of an embodiment of the embodiment in the engine brake rocker arm, wherein the brake piston of the brake mechanism is in the extended state.

[0022] Figure 2 is a schematic view of the positioning mechanism of the engine brake rocker arm of an embodiment of the embodiment in the engine brake rocker arm, wherein the brake piston of the brake mechanism is in the retracted state (engine ignition state).

[0023] Figure 3 is a partial enlarged sectional view of the positioning mechanism of the engine brake rocker arm of an embodiment of the embodiment.

[0024] Figure 4 Fig. 2 is a schematic view of the relative positions and sizes of two positioning grooves of different sizes on a rocker arm according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] The embodiments of the present application will be described in detail by the following specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification.

[0026] It should be understood that the structures, proportions, sizes, etc. shown in the drawings attached to the specification are only used to understand and read the content disclosed in the specification by those skilled in the art, and are not used to limit the implementation conditions of the present application, so they do not have technical substantive significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application. At the same time, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. in the specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the embodiments of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a specific orientation, structure and operation. Therefore, it cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance.

[0027] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be replaceably connected, or it can be integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0028] Embodiment:

[0029] As Figure 1 and Figure 2As shown, the engine brake rocker arm 210 (hereinafter referred to as rocker arm 210) is oscillatingly mounted on the engine rocker arm shaft 205 (the engine exhaust rocker arm can be mounted side-by-side with the engine brake rocker arm on the same rocker arm shaft, not shown here). The first end of the rocker arm 210 (here, the roller 235, or a push rod mechanism) has a brake cam 230, and the second end of the rocker arm 210 has an engine valve 301 (the valve stem of the valve 301 has a valve stem cap 405, the valve bridge 400 presses on the valve stem cap 405, and the engine exhaust rocker arm acts on the center of the valve bridge 400 to drive the two exhaust valves). An engine braking mechanism 100 is installed inside the rocker arm 210 above the valve 301.

[0030] When engine braking is required, the engine braking control mechanism (not shown) activates the fuel supply, the braking mechanism 100 opens, the brake piston 160 of the braking mechanism 100 extends downward, and the rocker arm 210 is in the position as shown. Figure 1 The connection positions are shown. Valve 301 is connected to the extended brake piston 160 via valve stem cap 405 (or directly via valve bridge 400); simultaneously, roller 235 is connected to the base circle 229 of brake cam 230. The movement of brake boss 231 (which may also have EGR or BGR bosses) on brake cam 230 is transmitted to engine valve 301 via rocker arm 210 and brake mechanism 100 in the extended state (brake piston 160 extended) within the rocker arm, generating the valve movement required for engine braking. Of course, the engine ignition valve movement (including exhaust valve movement) generated by the conventional valve drive mechanism (not shown) is always present and does not interfere with the braking valve movement (the valve opening phase and height for ignition and braking are different).

[0031] During normal ignition (non-engine braking) operation, the engine braking control mechanism (not shown) disconnects and discharges oil, the braking mechanism 100 closes (brake piston 160 retracts), and the rocker arm 210 tends to (automatically positioned by the cams 230 at both ends of the rocker arm 210 and the valves 301) as... Figure 2The non-collision position shown means that neither end of the rocker arm 210 (first end) interacts with the brake cam 230 (brake boss 231) nor with the valve 301 (valve cap 405). Specifically, a gap 212 is formed between the rocker arm 210 and the base circle 229 of the brake cam 230 (gap 212 is set by the adjusting screw 105 and the locking nut 115, and its size is not less than the lift of the brake cam, i.e., the height of the brake boss 231). This prevents the rocker arm 210 from being driven by the cam 230, and the movement of the cam 230 is lost, thus preventing the valve movement required for engine braking. Clearly, at this time, the rocker arm 210 is in a non-collision position on the rocker arm shaft 205 (which can be a relatively static positioning state) and is not driven by the engine braking cam 230. Note that the valve movement for engine ignition (including exhaust valve movement) is generated by a conventional valve drive mechanism (not shown) and is not affected by the engine brake.

[0032] In practical applications, due to the bumps / vibrations generated by vehicle operation, the rocker arm 210 at the two non-collision positions (which can be relatively stationary positioning states) on the rocker arm shaft 205 may be disturbed, causing the rocker arm 210 to collide with the cam 230 and / or the valve 301. In order to eliminate this disturbance, the positioning mechanism of the engine brake rocker arm in this embodiment is provided.

[0033] Positioning mechanism 50 for engine brake rocker arm Figure 3 This includes a positioning bolt 151 and a positioning spring 153. One end of the positioning bolt 151 is fixedly connected to the rocker arm shaft 205. One end of the positioning spring 153 abuts against the other end of the positioning bolt 151 (which can be a direct contact abutment), and the other end of the positioning spring 153 is movably abutting against the rocker arm 210. The positioning spring 153 generates motion resistance between the rocker arm 210 and the rocker arm shaft 205. Abutment can be understood as a connection with a force applied. Abutment can be direct contact with a force applied (direct contact abutment), or indirect contact with a force applied, etc. Contact can be a fixed connection or a non-fixed connection. Movable abutment can be understood as the two parts being able to move relative to each other while exerting a force. That is, the other end of the positioning spring 153 can move on the rocker arm 210 while exerting a force. Furthermore, movable abutment can include direct contact with a force applied, or indirect contact with a force applied. The other end of the positioning spring 153 can be in direct contact with the rocker arm 210, or it can be indirect contact. The presence of a washer, as mentioned later, represents a case of indirect contact.

[0034] In one embodiment of this utility model, the rocker arm 210 is provided with a positioning step hole 250 arranged radially along the rocker arm shaft 205. The positioning step hole 250 includes two positioning grooves 251 and 253 of different sizes. Figure 1、 Figure 2 and Figure 4 The positioning groove 251 is a large positioning groove 251, and the positioning groove 253 is a small positioning groove 253, and the small positioning groove 253 is arranged close to the rocker shaft 205. The positioning stepped hole 250 can be a through hole, that is, one end of the positioning stepped hole 250 is on the outer surface of the rocker 210, and the other end of the positioning stepped hole 250 is on the surface provided with the rocker hole. The stepped surface 252 is formed between the small positioning groove 251 and the large positioning groove 253.

[0035] In an embodiment of the utility model, the positioning bolt 151 is arranged in the positioning stepped hole 250 and is fixedly connected with the rocker shaft 205, the positioning bolt 151 is arranged in the two positioning grooves (the large positioning groove 251 and the small positioning groove 253) and is fixedly connected with the rocker shaft, and specifically, the positioning bolt 151 is fixed in the threaded hole 157 on the rocker shaft 205.

[0036] In an embodiment of the utility model, the other end of the positioning spring 153 is movably abutted with the stepped surface 252.

[0037] In an embodiment of the utility model, the positioning stepped hole 250 is provided with a avoiding space 254 for avoiding the positioning bolt 151, and when the rocker 210 rotates around the rocker shaft 205, the positioning bolt 151 rotates relatively in the avoiding space 253. Since the rocker shaft 205 is relatively static, the positioning bolt 151 fixedly connected with the rocker shaft 205 is also relatively static, and when the rocker 210 rotates around the rocker shaft 205, in fact, the positioning stepped hole 250 (the two positioning grooves) rotates on the outside of the positioning bolt 151, and it can be understood that the positioning bolt 151 rotates relatively in the avoiding space 254. The small positioning groove 251 and the large positioning groove 253 both include the avoiding space 254, and since the large positioning groove 253 is larger than the small positioning groove 253, if the small positioning groove 253 has the avoiding space 254, then the large positioning groove also has the avoiding space 254.

[0038] In an embodiment of the utility model, the small positioning groove 253 of the two positioning grooves has a predetermined length, and the length of the avoiding space 254 is formed on the predetermined length, and when the rocker 210 rotates around the rocker shaft 205, the predetermined length determines the distance of the positioning bolt 151 rotating relatively in the small positioning groove 253, and further controls the rotation angle of the rocker 210 on the rocker shaft 205. It should be noted that the length is Figure 4 longitudinal and lateral directions.

[0039] In an embodiment of the utility model, when the rocker arm 210 rotates around the rocker arm shaft 205, the other end of the positioning spring 153 moves on the step surface 252. Therefore, the avoiding space of the large positioning groove 253 is larger than that of the small positioning groove 251, and the avoiding space of the large positioning groove 253 not only avoids the positioning bolt 151, but also avoids the movement of the positioning spring 153.

[0040] In an embodiment of the utility model, Figure 4 The relative position and size of the two positioning grooves are shown, the width of the large positioning groove 251 is slightly larger than the outer diameter of the positioning spring 153, and the width of the small positioning groove 253 is slightly larger than the outer diameter of the positioning bolt 151. It should be noted that the width is Figure 4 The length in the up-down direction.

[0041] In an embodiment of the utility model, the two positioning grooves can be both long circular holes.

[0042] In an embodiment of the utility model, the positioning spring 153 is sleeved outside the positioning bolt 151, and the positioning spring 153 is located in the large positioning groove 251, one end of which is arranged on the positioning bolt 151 (here, the flange plate of the flange bolt), that is, one end of the positioning spring 153 abuts against (may be in contact with) the flange plate of the flange bolt, and the other end of the positioning spring 153 movably abuts against the rocker arm 210, which can be understood as that the force of the other end of the positioning spring 153 acts on the rocker arm 210, increases the movement resistance of the rocker arm 210 on the rocker arm shaft 205, and maintains the rocker arm 210 in the two non-collision positions on the rocker arm shaft 205. Note that at this time, the engine is in the ignition state (not in the engine braking state), the engine brake piston 160 in the rocker arm 210 is retracted (the arrow direction in the figure), Figure 2 the first end of the rocker arm 210 avoids the driving of the cam 230 (the gap 212), and the second end of the rocker arm 210 avoids the action with the engine valve 301. Once the rocker arm 210 is not driven by the cam 230, it will not fly off, and there is no need for a complex, large and expensive anti-flying-off mechanism.

[0043] In an embodiment of the present application, the positioning mechanism 50 further comprises a gasket 155, which is arranged on the stepped surface 252. The gasket 155 is arranged on the stepped surface 252 between the two positioning grooves and is sleeved on the outer side of the positioning bolt 151. The other end of the positioning spring 153 is arranged on the upper surface of the gasket 155 and is in contact with the upper surface of the gasket 155. The upper surface of the gasket 155 is pressed by the positioning spring 153, and the lower surface is supported by the stepped surface 252. The other end of the positioning spring 153 and the gasket 155 are movably in contact with the stepped surface 252. It can be understood that the other end of the positioning spring 153 acts on the rocker arm 210 through the gasket 155. In addition, when the rocker arm 210 rotates around the rocker arm shaft 205, the other end of the positioning spring 153 and the gasket 155 move together on the stepped surface 252.

[0044] It is noted that the positioning mechanism 50 increases the movement (rotation) resistance of the rocker arm 210 on the rocker arm shaft 205, which increases the engine braking power (friction work) but does not increase the fuel consumption of the engine, because the brake rocker arm 210 is stationary (no rotation, no friction work) during engine ignition.

[0045] The above examples are illustrative of the present embodiments and are not limiting. Indeed, those skilled in the art can readily devise modifications and variations of the present embodiments without departing from the scope and spirit of the present embodiments. For example, a function described or illustrated for one particular mechanism can be used for another mechanism, thus providing a new mechanism. The rocker arm in the embodiments can be other types of rocker arms, such as an EGR rocker arm or a rocker arm for engine variable valve drive, in addition to the engine brake rocker arm. In addition, the engine brake mechanism in the rocker arm 210 can be other mechanisms, such as EGR, in addition to the brake mechanism 100. Furthermore, the position and installation method of the positioning mechanism 50 can be different. Therefore, the present embodiments will include the above modifications and variations, as long as they are within the scope of the appended claims or equivalent thereof.

Claims

1. A positioning mechanism for an engine brake rocker arm, characterized in that: The rocker arm is rotatably mounted on the rocker arm shaft of the engine. The positioning mechanism applies a force between the rocker arm and the rocker arm shaft to increase the movement resistance of the rocker arm on the rocker arm shaft and keep the rocker arm in a non-collision position on the rocker arm shaft. In the non-collision position, one end of the rocker arm avoids the drive of the engine cam and the other end of the rocker arm avoids the action of the engine valve. The positioning mechanism includes a positioning bolt and a positioning spring. One end of the positioning bolt is fixedly connected to the rocker arm shaft, one end of the positioning spring abuts against the other end of the positioning bolt, and the other end of the positioning spring movably abuts against the rocker arm. The positioning spring applies a force between the rocker arm and the rocker arm shaft.

2. The positioning mechanism for the engine brake rocker arm as described in claim 1, characterized in that, The rocker arm includes a positioning step hole arranged radially along the rocker arm shaft. The positioning step hole includes two positioning slots of different sizes, with the smaller positioning slot being located close to the rocker arm shaft. A step surface is formed between the two positioning slots. The positioning bolt passes through the positioning step hole and is fixedly connected to the rocker arm shaft. The other end of the positioning spring is movably abutting against the step surface.

3. The positioning mechanism for the engine brake rocker arm as described in claim 2, characterized in that: The positioning step hole is provided with a clearance space to avoid the positioning bolt. When the rocker arm rotates around the rocker arm axis, the positioning bolt rotates relative to the rocker arm within the clearance space.

4. The positioning mechanism for the engine brake rocker arm as described in claim 3, characterized in that: The smaller positioning groove has a predetermined length, and the length of the clearance space is formed on the predetermined length. When the rocker arm rotates around the rocker arm axis, the predetermined length determines the distance that the positioning bolt rotates relative to the smaller positioning groove, thereby controlling the rotation angle of the rocker arm on the rocker arm axis.

5. The positioning mechanism for the engine brake rocker arm as described in claim 2, characterized in that: When the rocker arm rotates about the rocker arm axis, the other end of the positioning spring moves on the step surface.

6. The positioning mechanism for the engine brake rocker arm as described in claim 2, characterized in that: The positioning spring is sleeved on the outside of the positioning bolt and located in the large positioning groove.

7. The positioning mechanism for the engine brake rocker arm as described in claim 2, characterized in that: The width of the larger of the two positioning slots is slightly larger than the outer diameter of the positioning spring, and the width of the smaller of the two positioning slots is slightly larger than the outer diameter of the positioning bolt.

8. The positioning mechanism for the engine brake rocker arm as described in claim 2, characterized in that: The positioning mechanism further includes a gasket, which is disposed on the stepped surface between the two positioning grooves and sleeved on the outside of the positioning bolt, and the other end of the positioning spring is disposed on the upper surface of the gasket.

9. The positioning mechanism for the engine brake rocker arm as described in claim 8, characterized in that: When the rocker arm rotates about the rocker arm axis, the other end of the positioning spring and the washer move together on the step surface.

10. The positioning mechanism for the engine brake rocker arm as described in claim 1, characterized in that: The positioning bolt is a flange bolt, and one end of the positioning spring abuts against the flange of the flange bolt.

11. The positioning mechanism for the engine brake rocker arm as described in claim 1, characterized in that: The rocker arm shaft includes a threaded hole, which is arranged along the radial direction of the rocker arm shaft, and the positioning bolt is fixed in the threaded hole on the rocker arm shaft.

Images