Positioning mechanism for engine brake rocker

Abstract

A positioning mechanism for an engine braking rocker arm includes a positioning bolt and a positioning spring. One end of the positioning bolt is fixedly connected to the rocker arm shaft, and one end of the positioning spring abuts against the other end of the positioning bolt, while the other end of the positioning spring movably abuts against the rocker arm. The positioning spring generates motion resistance between the rocker arm and the rocker arm shaft. In this embodiment, the rocker arm does not move during non-engine braking operation, eliminating mechanism slippage, friction, and oil consumption, greatly reducing the frequency of use. The entire mechanism does not occupy space (especially not increasing height) or weight, has a compact structure, is easy to install, low in cost, and is durable and reliable.

Description

Technical Field:

[0001] This embodiment relates to the field of mechanics, and more particularly to engines, specifically a positioning mechanism for an engine brake rocker arm. Background technology:

[0002] Cummins Engine Company disclosed a dedicated brake rocker arm in U.S. Patent No. 5,626,116 (1997). The dedicated brake rocker arm houses a hydraulic brake drive mechanism, including a hydraulic piston. When engine braking is not required, the hydraulic piston in the dedicated brake rocker arm is in the retracted position, the dedicated brake rocker arm is separated from the valve, and the movement of the dedicated brake cam is skipped (lost), resulting in no braking valve movement. When engine braking is required, the hydraulic piston in the dedicated rocker arm is in the extended position, and the dedicated rocker arm transmits the movement of the dedicated brake cam to one of the two exhaust valves, generating the valve movement for engine braking.

[0003] US Patent 5,975,251 (1999) discloses a locking device for a dedicated brake rocker arm. In the non-braking (ignition) state, the dedicated brake rocker arm is locked to the rocker arm shaft, with both ends suspended, neither contacting the brake cam nor the brake valve. This locking device was used on the dedicated brake rocker arm of the Cummins ISX engine, but it was found to be unreliable. The rocker arm would swing back and forth on the rocker arm shaft and impact, causing engine damage. Clearly, during braking, the rocker arm can rotate freely on the rocker arm shaft and cannot be positioned, potentially leading to collisions with the cam or valve, resulting in poor reliability.

[0004] Existing dedicated brake rocker arms utilize springs to bias them against a cam, making them driveed by the cam. For example, in Chinese utility model patent CN201666172U, the rocker arm is biased against the brake cam by a spring mounted between a bracket and a pressure plate. This requires adding a special spring bracket to the engine, occupying significant space, making installation inconvenient, and costly. Since the rocker arm is constantly driven by the brake cam (moving during ignition and braking), it experiences useless movement during engine ignition, greatly increasing its usage frequency, wear, and impact. Furthermore, the spring must have a large preload to maintain constant contact between the engine brake rocker arm and the camshaft during camshaft rotation (preventing it from disengaging). Summary of the Invention:

[0005] The purpose of this embodiment is to provide a positioning mechanism for an engine brake rocker arm. This positioning mechanism for an engine brake rocker arm aims to solve the technical problems in the prior art, such as poor reliability of the locking mechanism of the engine brake rocker arm, the rocker arm requiring a spring with a large preload and a special bracket, large space occupation, inconvenient installation and high cost, as well as the rocker arm generating useless movement during engine ignition, increasing the frequency of use, wear and fuel consumption.

[0006] In a first aspect, the present invention provides a positioning mechanism for an engine brake rocker arm, wherein the rocker arm is rotatably mounted on a rocker arm shaft of the engine, and a buffer mechanism applies a force between the rocker arm and the rocker arm shaft to increase the resistance to movement of the rocker arm on the rocker arm shaft and to 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 camshaft and the other end of the rocker arm avoids interaction with the engine valves.

[0007] 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 is movably abuts against the rocker arm. The positioning spring applies a force between the rocker arm and the rocker arm shaft.

[0008] Optionally, one end of the positioning spring contacts and abuts against the other end of the positioning bolt.

[0009] Optionally, 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 interior of 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.

[0010] Optionally, 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.

[0011] Optionally, 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.

[0012] Optionally, when the rocker arm rotates about the rocker arm axis, the other end of the positioning spring moves on the step surface.

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

[0014] Optionally, 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.

[0015] Optionally, 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.

[0016] Optionally, 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.

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

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

[0019] Optionally, the rocker arm shaft includes a threaded hole 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.

[0020] Compared with existing technologies, this embodiment offers positive and significant advantages. This embodiment positions the rocker arm in a position where it does not collide with either the brake cam or the engine valves, and is not driven by the brake cam. In the non-braking (ignition) state of the engine, the rocker arm does not move at all, reducing wear and fuel consumption, and enhancing reliability and durability. Furthermore, the positioning mechanism of this embodiment does not occupy space (especially not increasing height) or add weight; it has a compact structure, is easy to install, has high reliability, and is low in cost. Attached image description:

[0021] Figure 1 This is a schematic diagram of the positioning mechanism of the engine brake rocker arm in the first embodiment of this invention, wherein the brake piston of the braking mechanism is in the extended state.

[0022] Figure 2 This is a schematic diagram of the positioning mechanism of the engine brake rocker arm in the first embodiment of this invention, wherein the brake piston of the braking mechanism is in the retracted state (engine ignition state).

[0023] Figure 3 This is a partially enlarged cross-sectional view of the positioning mechanism of the engine brake rocker arm according to the first embodiment of this invention.

[0024] Figure 4 This is a schematic diagram showing the relative positions and sizes of two positioning slots of different sizes on the rocker arm in the first embodiment of this invention. Detailed implementation method:

[0025] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0026] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that the present invention can achieve, should still fall within the scope of the technical content disclosed in the present invention. Furthermore, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., used in this specification to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a replaceable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0028] Example:

[0029] like 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 two non-collision positions shown indicate 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 two-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 still applying a force. That is, the other end of the positioning spring 153 can move on the rocker arm 210 while applying 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 the present invention, the rocker arm 210 is provided with a positioning step hole 250 arranged radially along the rocker arm shaft 205, and the positioning step hole 250 includes two positioning grooves 251 and 253 of different sizes. Figure 1 , Figure 2 and Figure 4 Positioning groove 251 is a large positioning groove 251, and positioning groove 253 is a small positioning groove 253, with the small positioning groove 253 located near the rocker arm shaft 205. The positioning stepped hole 250 can be a through hole, meaning one end of the positioning stepped hole 250 is on the outer surface of the rocker arm 210, and the other end is on the surface with the rocker arm hole. A stepped surface 252 is formed between the small positioning groove 251 and the large positioning groove 253.

[0035] In one embodiment of the present invention, the positioning bolt 151 passes through the interior of the positioning step hole 250 and is fixedly connected to the rocker arm shaft 205. The positioning bolt 151 passes through two positioning grooves (large positioning groove 251 and small positioning groove 253) and is fixedly connected to the rocker arm shaft. Specifically, the positioning bolt 151 is fixed in the screw hole 157 on the rocker arm shaft 205.

[0036] In one embodiment of the present invention, the other end of the positioning spring 153 is movably abutting against the stepped surface 252.

[0037] In one embodiment of the present invention, a clearance space 254 for the positioning step hole 250 is provided to avoid the positioning bolt 151. When the rocker arm 210 rotates around the rocker arm shaft 205, the positioning bolt 151 rotates relative to the rocker arm shaft 205 within the clearance space 253. Since the rocker arm shaft 205 is relatively stationary, the positioning bolt 151, which is fixedly connected to the rocker arm shaft 205, is also relatively stationary. When the rocker arm 210 rotates around the rocker arm shaft 205, the positioning step hole 250 (two positioning grooves) actually rotates outside the positioning bolt 151. This can be understood as the positioning bolt 151 rotating relative to the rocker arm shaft 254. Both the small positioning groove 251 and the large positioning groove 253 include the clearance space 254. Since the large positioning groove 253 is larger than the small positioning groove 253, if the small positioning groove 253 has a clearance space 254, then the large positioning groove also has a clearance space 254.

[0038] In one embodiment of the present invention, the smaller positioning groove 253 of the two positioning grooves has a predetermined length, forming a clearance space 254. When the rocker arm 210 rotates around the rocker arm shaft 205, the predetermined length determines the distance that the positioning bolt 151 rotates relative to the smaller positioning groove 253, thereby controlling the rotation angle of the rocker arm 210 on the rocker arm shaft 205. It should be noted that the length is... Figure 4 The length in the left-right direction.

[0039] In one embodiment of the present invention, when the rocker arm 210 rotates around the rocker arm shaft 205, the other end of the positioning spring 153 moves on the stepped surface 252. Therefore, the clearance space of the larger positioning groove 253 is larger than that of the smaller positioning groove 251. The clearance space of the larger positioning groove 253 must not only accommodate the positioning bolt 151, but also accommodate the movement of the positioning spring 153.

[0040] In one embodiment of the present invention, Figure 4 The relative positions and sizes of the two positioning slots are shown. The width of the larger positioning slot 251 is slightly larger than the outer diameter of the positioning spring 153, and the width of the smaller positioning slot 253 is slightly larger than the outer diameter of the positioning bolt 151. It should be noted that the width is... Figure 4 Length in the vertical direction.

[0041] In one embodiment of the present invention, both positioning grooves may be elongated holes.

[0042] In one embodiment of the present invention, a positioning spring 153 is sleeved on the outside of a positioning bolt 151, and the positioning spring 153 is located in a larger positioning groove 251. One end of the positioning spring 153 is placed on the positioning bolt 151 (on the flange of the flange bolt shown here), that is, one end of the positioning spring 153 abuts against the flange of the flange bolt (it can be a contact abutment), and the other end of the positioning spring 153 is movably abutting against the rocker arm 210. It can be understood that the force of the other end of the positioning spring 153 acts on the rocker arm 210, increasing the movement resistance of the rocker arm 210 on the rocker arm shaft 205, and maintaining the rocker arm 210 in a non-collision position on the rocker arm shaft 205. Note that this is the engine ignition state (not engine braking), and the engine brake piston 160 in the rocker arm 210 retracts ( Figure 2 The first end of the rocker arm 210 avoids the drive of the cam 230 (clearance 212), and the second end of the rocker arm 210 avoids interaction with the engine valve 301. Once the rocker arm 210 is no longer driven by the cam 230, there will be no fly-off, and there will be no need for a complex, large and expensive anti-fly-off mechanism.

[0043] In one embodiment of the present invention, the positioning mechanism 50 further includes a washer 155, which is disposed on the stepped surface 252. The washer 155 is disposed on the stepped surface 252 between the two positioning grooves and sleeved on the outside of the positioning bolt 151. The other end of the positioning spring 153 is disposed on the upper surface of the washer 155 and contacts the upper surface of the washer 155. The upper part of the washer 155 is pressed by the positioning spring 153, and the lower part is supported by the stepped surface 252. The other end of the positioning spring 153 and the washer 155 are in movable contact with the stepped surface 252. It can be understood that the other end of the positioning spring 153 applies force to the rocker arm 210 through the washer 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 washer 155 move together on the stepped surface 252.

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

[0045] The examples above are illustrative of this embodiment and not intended to limit it. In fact, those skilled in the art can readily modify and vary this embodiment within its scope and principles. For example, a certain function described or illustrated in one specific mechanism can be used in another specific mechanism, resulting in a new mechanism. The rocker arm in the embodiment can be other types of rocker arms besides an engine braking rocker arm, such as an EGR rocker arm or a rocker arm for engine variable valve timing. Furthermore, the engine braking mechanism within the rocker arm 210 can be other mechanisms besides the braking mechanism 100, such as an EGR mechanism. Also, the position and mounting method of the positioning mechanism 50 can be different. Therefore, this embodiment will include the above modifications and variations, provided they fall within the scope of the appended claims or equivalent claims.

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 buffer 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. Optionally, 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.

9. 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.

10. 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