Shift detent latch assembly for a rocker arm

Abstract

A shift detent latch assembly (2001) for a rocker arm (50, 60) can include a latch assembly housing (200) including a latch assembly oil supply, a piston bore (201), a detent bore (203) including a detent opening (204), and a spring seat (206). A piston (210) can be located in the piston bore. A shift detent (220) can be located in the detent bore, and the shift detent can include a protrusion (224) protruding from the detent opening. A return spring (230) can be configured in the spring seat to bias the shift detent and plunger away from the spring seat and toward the latch assembly oil supply. A valve train (1, 2, 3) can include a rocker arm configured to be actuated against a cam (31) on a cam rail (30), and the rocker arm can include a latch surface (57, 67) configured to selectively engage and disengage the protrusion.

Description

Technical Field

[0001] This application provides a displacement stop latch assembly for a rocker arm and the rocker arm formed therefrom. Background Technology

[0002] Variable valve actuation (VVA) technology can result in a large accumulation on the valve mechanism, where the actuator extends upwards or behind the rocker arm. The space in the cylinder head is sealed, which is why VVA parts are typically moved upwards or backwards. This also leads to encapsulation issues in the engine compartment. Reliable, low-parts-count, compact, and lightweight switching is what is desired when moving between variable valve lift profiles. Summary of the Invention

[0003] The methods and apparatus disclosed herein overcome the aforementioned drawbacks and improve upon the prior art through the valve mechanism's shift stop latch assembly and the valve mechanism thus formed. A support for the valve mechanism can also be formed. The valve mechanism may include a rocker arm, a cam actuation system, and a shift stop configured to selectively act on the rocker arm. A type III rocker arm may be configured with a shift stop as shown and described in the figures. A type III rocker arm may be configured with a shift stop adjacent to a roller or pushrod as shown and described in the figures.

[0004] A shift stop latch assembly for a rocker arm may include a latch assembly housing comprising a latch assembly oil supply, a piston bore, a stop bore including a stop opening, and a spring seat. The piston may be located in the piston bore. The shift stop may be located in the stop bore and may include a protrusion projecting from the stop opening. A return spring may be configured in the spring seat to bias the shift stop and plunger away from the spring seat and toward the latch assembly oil supply.

[0005] The valve mechanism may include a rocker arm configured to abut against a cam track and actuate a cam, and the rocker arm may include a latching surface configured to selectively engage and disengage a protrusion.

[0006] The rocker arm may include a body extension of a support surface adjacent to the end of the cam. A latching surface may be integrated with the body extension. A latching housing may be at least partially nested beneath the body extension. Furthermore, when included, the rocker arm extension may be at least partially nested beneath the body extension.

[0007] Other objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description or may become apparent by practice of the disclosure. These objects and advantages will also be achieved and attained by means of the elements and combinations particularly pointed out in the appended claims. Attached Figure Description

[0008] Figures 1A to 1CA perspective view of an alternative displacement stop latch assembly and rocker arm in an alternative valve mechanism configuration is shown.

[0009] Figure 2 This is a view of a shift stop latch assembly within a shift stop latch assembly.

[0010] Figure 3A and Figure 3B This is a comparative view of the rocker arm in its lowered and raised states relative to the unlocked displacement stop latch assembly.

[0011] Figure 4A and Figure 4B This is a comparative view of the rocker arm in its lowered and raised states relative to the unlocked displacement stop latch assembly.

[0012] Figure 5 This is a view of the alternative displacement stop latch assembly and its rocker arm. Detailed Implementation

[0013] The examples shown in the accompanying drawings will now be referred to in detail.

[0014] The displacement stop 220 used for rocker arms 50 and 60 can be used to achieve cylinder decompression (CDC). The displacement stop 220 enables variable valve actuation (VVA). It can be used in heavy-duty engines to achieve cylinder decompression (CDC) mode. Benefits include simple and robust design.

[0015] Internal combustion engines are forced to reduce fuel consumption and exhaust emissions. One possible way is to use a cylinder depressurization (CDC) system in the engine valve mechanism 1, 2, and 3. CDC reduces the pressure drop in the cylinder. This reduces the torque required to rotate the crankshaft. This is beneficial in a variety of applications:

[0016] ● Start / Stop System - Lower power consumption and lower vibration during repeated start-ups and shutdowns.

[0017] ● Hybrid powertrain - Seamless switching between ICE and electric motor modes.

[0018] ● Coasting in vehicles with internal combustion engines (ICE) - replacing cylinder deactivation for lower fuel consumption during low-load conditions.

[0019] The proposed CDC system includes a shift stop 220 with a simple yet robust design. This design is flexible and can be modified for different engines depending on engine layout and available space. However, the design can be easily customized, and a robust CDC system can be delivered to OEMs. For example, the shift stop 220 can be selected to suit customer specifications, where the height of the protrusion 224 drives the degree of cylinder decompression (the degree to which the valve remains open). The shift stop 220 can now be scaled in one direction, while the remainder of the rocker arms 50, 60 remains available for other customer configurations. The stroke length of the shift stop 220 can be adjusted by widening the stop opening 204 or by keeping it narrow. The travel and range of the latch surfaces 57, 67 can then be varied for lift height adjustment.

[0020] A displacement stop 220 may be present near rocker arms 50 and 60. The latch assembly housing 200 for the displacement stop 220 may be housed within latch bodies 81, 91, and 101, and may be nested against rocker arms 50 and 60, or nested within recesses in rocker arms 50 and 60. The displacement stop 220 may be pushed to the engaged position by its return spring 230, and may be hydraulically pushed to the disengaged position by piston 210. Without hydraulic pressure, piston 210 is not pushed, displacement stop 220 is displaced to the engaged position, and rocker arm movement is restricted by displacement stop 220, preventing engine valves from closing. (Reference) Figure 4A and Figure 4B CDC mode is activated. When the oil is pressurized, piston 210 presses against return spring 230, displacement stop 220 is disengaged, rocker arms 50 and 60 move freely, support surfaces (roller bearings or sliding pads) 56 and 66 follow the rotating cam 31 of cam track 30, and engine valves can be closed. CDC mode is deactivated. (Reference) Figure 3A and Figure 3B .

[0021] Advantages may include a simple and robust design, ease of customization for different engines, the ability to be designed without opening and closing ramps, acceptance of low crankshaft speeds (RPM) for start / stop systems, and the ability to redesign valve profiles.

[0022] The shift stop latch assembly 2001 for rocker arms 50, 60 may include a latch assembly housing 200, which includes a latch assembly oil hole 2021, a piston hole 201, a stop hole 203 including a stop opening 204, and a spring seat 206. A piston 210 may be located in the piston hole 201. A shift stop 220 may be located in the stop hole 203, and the shift stop 220 may include a protrusion 224 projecting from the stop opening 204. A return spring 230 may be configured in the spring seat 206 to bias the shift stop 220 and the plunger 210 away from the spring seat 206 and toward the latch assembly oil hole 2021.

[0023] The latch assembly housing 200 may include a stepped bore structure, such as a step 2031 for a stop bore. A piston 210 may be inserted into this piston bore 201. The piston bore 201 may include a piston rear wall 202 through which a latch assembly oil orifice 2021 provides oil control. A fitting 213 may be formed on the piston body 214 to space the piston 210 from the piston rear wall 202, thereby facilitating oil flow around the piston 210 during oil control.

[0024] The latch assembly oil port 2021 can be connected to the oil passage 41 in the rocker arm shaft 40 via different connections to the rocker arm shaft oil supply portion 42. When the displacement stop latch assembly 2001 is mounted in the anchored latch assembly body 80 or in the integrated latch assembly body 100, a portion of the latch bodies 81, 91 may include a latch oil supply portion 941 extending from the latch assembly oil port 2021. The rocker arm oil supply portion 69 may be fluidly connected to the latch oil supply portion 941. When the anchored latch assembly body 90 is included (which includes the latch body 91 and the rocker arm extension 93), the latch assembly oil port 2021 may be configured to be directly connected to the extended oil supply portion 94 for fluid communication with the rocker arm shaft oil supply portion.

[0025] Several alternative options are shown in valve mechanisms 1, 2, and 3. Figure 1A and Figure 1B In this configuration, bracket 10 can be mounted to the cylinder head. Rocker arm shaft 40 is shown as having an option to be stable relative to bracket 10. Additional mounting holes 11, 12 are shown in bracket body 13. Brackets 82, 92 can be integrated with latch bodies 81, 91 to anchor displacement stop latch assembly 2001 relative to bracket 10. Fasteners 24 (such as screws, rivets, locating pins, etc.) can be used to anchor brackets 82, 92 to bracket 10. However, in... Figure 1CIn this design, bracket 20 is more integrated. It can also stabilize rocker arm shaft 40 and can include mounting holes 21, 22 in bracket body 23. However, as an alternative to the bracket, latch body 101 is integrated with bracket 20 as an integrated latch assembly body 100. Latch assembly housing 200 is integrated in bracket body 23, and bracket body 23 is configured to be mounted to the cylinder head of the engine and to anchor rocker arm shaft 40 to the cylinder head.

[0026] The latch assembly housing 200 may be configured with a bracket 92 for mounting to the valve mechanism bracket 10. The latch assembly housing 200 may be configured with a rocker arm extension 93. The rocker arm extension 93 may be configured to receive the rocker arm shaft 40 in an extended rocker arm shaft bore 940. The rocker arm extension 93 includes an extended oil supply portion 94 from the extended rocker arm shaft bore 940 to the latch assembly oil port 2021.

[0027] The stop opening 204 of the stop hole 204 may be configured to reciprocate around the protrusion 224 of the displacement stop 220 within the stop hole 204. A first opening end wall 2041 and a second opening end wall 2042 of the stop opening 204 are configured as travel stops for the displacement stop 220. Alternatively or additionally, the stop hole 204 may include a stop hole step 2031 configured as a travel restriction for the displacement stop 220. Alternatively or additionally, a piston 210 may be configured to protrude from a piston hole 201 to restrict the travel of the displacement stop 220. A first end 211 of the piston may protrude from the piston hole 201. The piston 210 may optionally engage to position the displacement stop 220. With the second end 212 of the piston adjacent to the piston rear wall 202, the length of the piston body 214 can be selected to facilitate the positioning of the protrusion 224 relative to the latching surfaces 57, 67 of the rocker arms 50, 60, limited by the optional pipe fitting 213.

[0028] The shift stop latch assembly 2001 facilitates a quick and reliable plug-in assembly technique. The piston 210 is inserted into the piston bore 201 through the vent hole 207. The shift stop 220 is inserted through the stop opening 204 in the stop bore 203. Then, the return spring 230 (in...) Figure 3A , Figure 4A and Figure 5(Only its ends are shown) can be inserted into the spring cap 226 in the stop body 223. The first end 221 of the displacement stop 220 may be adjacent to the spring seat 206, and the second end 222 of the displacement stop 220 may be adjacent to the first end 211 of the piston 210. When the return spring 230 is inserted, the retainer 240 for the return spring 230 may be configured for insert assembly. The retainer 240 may include a spring seat and a spring guide. Alternatively, a step or flange may be formed in the spring seat 206. Anchoring fasteners such as C-clamps 250, bushings, posts, washers, internal nuts, etc., can lock the components of the displacement stop latch assembly 2001 in place.

[0029] To prevent rotation of the displacement stop 220, a guide arrangement can be implemented. This guide arrangement can be used to keep the spring cap 226 aligned in the stop hole 201, or to align the protrusion 224 with the latch surfaces 57, 67. Therefore, a guide surface 225 can be formed on the displacement stop 220. The guide insert can be a pin located in the guide pin slots 208, 209. The guide insert 260 can be a bolt, pin, stake, strip, tenon, or other means. The guide insert can also be used to secure the displacement stop 220 so that it does not fall out through the stop opening 204. The guide insert 260 can be installed across the stop opening 204 and aligned against the guide surface 225.

[0030] Valve mechanisms 1, 2, and 3 may include rocker arms 50 and 60 configured to be actuated against a cam 31 on a cam track 30. Rocker arms 50 and 60 may include latching surfaces 57 and 67 configured to selectively engage and disengage protrusions 224. That is, as... Figure 3A and Figure 3B As shown, the displacement stop 220 can be configured to disengage from the latch surfaces 57, 67 by sliding the displacement stop 220 in the stop opening 204 to abut against the first opening end wall 2041. Alternatively, as Figure 4A , Figure 4B and Figure 5 As shown, the displacement stop can be configured to engage the latch surfaces 57, 67 by sliding the displacement stop 220 in the stop opening 204 to abut the second opening end wall 2042.

[0031] Rocker arms 50, 60 include rocker arm bodies 51, 61 through which rocker arm shaft holes 52, 62 are formed. Valve ends 53, 63 may include insertion holes 54, 64 for receiving inserts 71 (such as sockets, seals, clearance adjusters, piston assemblies, ferrules, and other options). A clearance nut 72 is shown. Valve ends 53, 63 may also include e-foots 73 for actuating one or more valves 75, thus the valve bridge 74 is shown having two valves 75.

[0032] The cam ends 55 and 65 of the rocker arms 50 and 60 may include support surfaces 56 and 66 for actuating the cam 31 on the cam track 30. When the cam 31 rotates, it raises and lowers the rocker arms 50 and 60 to actuate the valve 75. When the cam 31 is on the base circle, the support surfaces 56 and 66 in the cam ends 55 and 65 are not raised, therefore the latching surfaces 57 and 67 are lowered, as... Figure 3A , Figure 4A and Figure 5 As shown. In Figure 3A In this configuration, latching surfaces 57 and 67 extend beyond the displacement stop 220, and valve 75 can be fully closed. Latching surfaces 57 and 67 are adjacent to, but not contiguous with, the displacement stop 220. Figure 4A and Figure 5 In the case where the support surface is located on the base circle, the valve cannot close completely because protrusion 224 interferes with the rocker arm's descent. Figure 4A In the middle, a gap can be seen between the cam 31 and the support surface 56. The drive mode lift of the valve 75 is not affected by the shift stop latch assembly 2001 because when the cam 31 rotates to the lift cam angle, the latch surfaces 57, 67 can be lifted away from the protrusion 224. This can... Figure 3B and Figure 4B I saw it in the middle.

[0033] The rocker arms 50 and 60 may include body extensions 570 and 670 on support surfaces 56 and 66 adjacent to the cam ends 55 and 65. Latch surfaces 57 and 67 may be integrated with the body extensions 570 and 670. The body extensions 570 and 670 provide structural integrity for the rocker arms 50 and 60, which typically bend between the actuation cam and the valve end. The body extensions 570 and 670 may be formed as overhangs, with actuator seats 58 and 68 formed below them. The latch assembly housing 200 may then be at least partially nested below the body extensions 570 and 670. Furthermore, when included, the rocker arm extension 93 may be at least partially nested below the body extension 670. This nesting provides a compact valve mechanism arrangement. The linear space between cylinders is maximized by nesting the shift stop latch assembly 2001 against the rocker arms 50 and 60. Unlike existing technologies, the use of vertical and backward space can be avoided for mode switching features.

[0034] Given the descriptions and practices of the examples disclosed herein, other implementations will be obvious to those skilled in the art.

Claims

1. A displacement stop latch assembly for a rocker arm, comprising: A latch assembly housing, the latch assembly housing comprising: Lubrication section for latch assembly; Piston bore; Stop hole, the stop hole including stop opening; and Spring seat; Piston, the piston being disposed in the piston bore; A displacement stop, disposed between the piston and the spring seat in the stop bore, the displacement stop including a protrusion projecting from the stop opening; and A return spring, disposed in the spring seat, biases the displacement stop and the piston away from the spring seat and toward the latch assembly oil supply section. In the absence of oil pressure from the latch assembly's oil supply section, the return spring is configured to push the displacement stop from the disengaged position to the engaged position to initiate the cylinder decompression mode. When the cylinder is in decompression mode, the protrusion of the displacement stop engages with the cam end of the rocker arm to prevent the rocker arm from descending.

2. The displacement stop latch assembly according to claim 1, further comprising: A guide insert is mounted across the opening of the stop and aligned with a guide surface on the displacement stop.

3. The displacement stop latch assembly of claim 1, wherein the latch assembly housing is integrated into a bracket body configured to be mounted to a cylinder head.

4. The displacement stop latch assembly of claim 3, wherein the bracket body is configured to anchor the rocker arm shaft to the cylinder head.

5. The shift stop latch assembly of claim 1, wherein the latch assembly housing further includes a bracket configured to be mounted to a valve mechanism bracket.

6. The displacement stop latch assembly of claim 5, wherein the latch assembly housing further includes a rocker arm extension configured to receive a rocker arm shaft in an extended rocker arm shaft bore.

7. The shift stop latch assembly of claim 6, wherein the rocker arm extension includes an extended oil supply portion extending from the extended rocker arm shaft hole to the oil supply portion of the latch assembly.

8. The displacement stop latch assembly according to any one of claims 1 to 7, wherein the stop opening is configured to reciprocate around the protrusion in the stop hole, and wherein the stop opening includes a first opening end wall and a second opening end wall, the first opening end wall and the second opening end wall being configured as a travel stop of the displacement stop.

9. The displacement stop latching assembly according to any one of claims 1 to 7, wherein the stop hole includes a stop hole step, the stop hole step being configured as a travel restriction of the displacement stop.

10. The displacement stop latching assembly according to any one of claims 1 to 7, wherein the piston is configured to protrude from the piston bore to restrict the travel of the displacement stop.

11. The displacement stop latch assembly according to any one of claims 1 to 7, further comprising a retainer configured for insert assembly of the return spring into the displacement stop and the spring seat.

12. A valve mechanism comprising a shift stop latch assembly as described in any of the preceding claims, the valve mechanism further comprising a rocker arm configured to abut against a cam track and actuated by a cam, the rocker arm including a latch surface configured to selectively engage and disengage the protrusion.

13. The valve mechanism of claim 12, wherein the rocker arm further includes a body extension of a support surface adjacent to a cam end of the rocker arm, and wherein the latching surface is integrated with the body extension.

14. The valve mechanism of claim 13, wherein the latch assembly housing is at least partially nested beneath the body extension.

15. The valve mechanism of claim 13, wherein the rocker arm extension is nested below the body extension when the rocker arm extension is included in the shift stop latch assembly of claim 6 or 7.

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