JP2018519466A - Switching rocker arm for internal exhaust gas recirculation with simple latch control - Google Patents

Abstract

A switching rocker arm configured in accordance with an example of the present disclosure includes an outer arm, an inner arm, a latch, a roller, a first lost motion spring, and a second lost motion spring. The outer arm has a first outer side arm, a second outer side arm, a first end of the outer arm, and a second end of the outer arm. The first outer side arm has a first leg retention tab. The second outer side arm has a second leg retention tab. The inner arm is pivotally secured to the outer arm and has a latch hole, a first inner side arm, a second inner side arm, a first end of the inner arm, and a second end of the inner arm. . The first end of the inner arm has a first finger, a second finger, a first hub, and a second hub.
[Selection] Figure 1

Description

This application claims priority to Indian Provisional Application No. 1943 / DEL / 2015, filed June 29, 2015, which is incorporated herein by reference in its entirety. .

  The present disclosure generally relates to a switching roller finger follower or rocker arm in an internal combustion engine.

  Variable valve actuation (VVA) technology has been introduced and demonstrated. One VVA device is a variable valve lift (VVL) system, in US Pat. No. 8,215,275, whose title is “Single Lobe Deactivating Rocker Arm”, which is incorporated herein by reference in its entirety. It may be a cylinder deactivation (CDA) system as described, or other valve actuation system. Such mechanisms have been developed to improve engine performance, fuel economy, and / or reduce engine emissions. Some types of VVA rocker arm assemblies include an inner rocker arm within an outer rocker arm that is biased with a torsion spring.

  The switching rocker arm allows control of valve actuation by alternating between a latched state and an unlatched state. When in the latched position, the latch moves both the inner and outer rocker arms as a single unit. When in the unlatched position, the rocker arms are allowed to move independently of each other. In some situations, these arms can engage different cam lobes such as low lift lobes, high lift lobes, and non-lift lobes. The mechanism is required for switching rocker arm mode in a manner suitable for operation of the internal combustion engine.

  The background art provided herein is for the purpose of generally presenting the contents of the present disclosure. To the extent described in this background section and in the illustrative embodiments that may not otherwise qualify as prior art at the time of filing, the inventors' work listed in the present invention is either Not implied.

  A switching rocker arm configured in accordance with an example of the present disclosure includes an outer arm, an inner arm, a latch, a roller, a first lost motion spring, and a second lost motion spring. The outer arm has a first outer side arm, a second outer side arm, a first end of the outer arm, and a second end of the outer arm. The first outer side arm has a first leg retention tab. The second outer side arm has a second leg retention tab. The inner arm is pivotally secured to the outer arm and has a latch hole, a first inner side arm, a second inner side arm, a first end of the inner arm, and a second end of the inner arm. The first end of the inner arm has a first finger, a second finger, a first hub, and a second hub. The latch is slidably connected to the inner arm with a latch hole and is configured to selectively extend to engage the outer arm. Rollers and bearings are configured on the inner arm. First and second lost motion springs are mounted on the respective first and second hubs and configured to bias the inner arm. The first and second lost motion torsion springs each have a first leg and a second leg. The first leg of the first lost motion spring is engaged with the second leg retaining tab. The second leg of the first lost motion spring is engaged with the second finger. The first leg of the second lost motion spring is engaged with the first leg retaining tab. The second leg of the second lost motion torsion spring is engaged with the first finger. The first and second fingers of the inner arm, and the first and second leg retaining tabs are all located in the middle of (i) the first and second hubs and (ii) the bearing.

  According to a further feature, the switching rocker arm further comprises a slider pad configured on the outer arm. The roller and bearing cooperate to accommodate the main lift and the slider pad is configured to accommodate the secondary lift. The latch and the first and second torsion springs are positioned at the first end of the inner arm. The inner arm further includes a socket disposed at the first end of the inner arm and a valve pad positioned at the second end of the inner arm. The pivot shaft can rotatably connect the inner arm and the outer arm. The second end of the outer arm extends substantially above the pivot axis in a direction generally opposite to the valve pad. The socket is configured to receive the ball plunger end of a dual feed hydraulic lash adjuster.

  According to other features, the inner arm further comprises a rear stop configured to selectively engage the outer arm. The first and second ends of both the first and second lost motion springs do not engage the first end of the outer arm. The first and second lost motion torsion springs have respective coil portions mounted on the respective first and second hubs. The first and second leg retaining tabs are each in the form of a generally hook having a respective extension. The first leg of the first lost motion spring is positioned between the first outer side arm and the extension of the first leg retaining tab. The second leg of the second lost motion spring is positioned between the second outer side arm and the extension of the second leg retaining tab.

  A switching rocker arm configured in accordance with another example of the present disclosure includes an outer arm, an inner arm, a latch, rollers and bearings, first and second lost motion torsion springs, and a pivot shaft. The inner arm is pivotally fixed to the outer arm and has a latch hole. The inner arm has a first inner side arm, a second inner side arm, a first end of the inner arm having a socket, and a second end of the inner arm having a valve pad, the first of the inner arm The end has a first finger, a second finger, a first hub, and a second hub. The latch is slidably connected to the inner arm with a latch hole and is configured to selectively extend to engage the outer arm. Rollers and bearings are configured on the inner arm. First and second lost motion torsion springs are mounted on the respective first and second hubs and configured to bias the inner arm. The first and second lost motion torsion springs can each have a first leg and a second leg. The first leg of the first lost motion spring is engaged with the second leg retaining tab. The second leg of the first lost motion spring is engaged with the second finger. The first leg of the second lost motion spring is engaged with the first leg retaining tab. The second leg of the second lost motion torsion spring is engaged with the first finger. The pivot shaft rotatably connects the inner arm and the outer arm. The second end of the outer arm extends substantially above the pivot axis in a direction generally opposite to the valve pad.

  According to other features, the first and second fingers of the inner arm and the first and second leg retaining tabs are all in the middle of (i) the first and second hubs and (ii) the bearing. It is positioned. The slider pad is configured on the outer arm. The rollers and bearings cooperate to accommodate the main lift. The slider pad is configured to accommodate a secondary lift. The latch and the first and second torsion springs are positioned at the first end of the inner arm. The socket is configured to receive the ball plunger end of a dual feed hydraulic lash adjuster. The inner arm further includes a rear stop configured to selectively engage the outer arm. The first and second ends of both the first and second lost motion torsion springs do not engage the first end of the outer arm.

  According to still other features, the first and second lost motion torsion springs have respective coil portions mounted on the respective first and second hubs. The first and second leg retaining tabs are each in the form of a generally hook having a respective extension. The first leg of the lost motion spring is positioned between the first outer side arm and the extension of the first leg retaining tab. The second leg of the second lost motion spring is positioned between the second outer side arm and the extension of the second leg retaining tab.

  The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

2 is a top perspective view of an exemplary switching rocker arm configured in accordance with an example of the present disclosure. FIG. It is a bottom perspective view of the switching rocker arm of FIG. It is an exploded view of the switching rocker arm of FIG. It is a side view of the switching rocker arm of FIG. It is a top view of the switching rocker arm of FIG. FIG. 2 is a first end view of the switching rocker arm of FIG. 1. FIG. 6 is a second end view of the switching rocker arm of FIG. 1. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 5. FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. 5.

  With reference to FIGS. 1-9, an exemplary switching rocker arm assembly, constructed in accordance with an example of the present disclosure, is indicated generally at 10 and is generally identified. The switching rocker arm assembly 10 is mounted on a piston driven internal combustion engine and is operated by a combination of a dual feed hydraulic lash adjuster (DFHLA) 12 (FIG. 8) and an oil control valve (OCV). It may be a single lobe cylinder deactivation (CDA-1L) switching rocker arm. The switching rocker arm assembly 10 can be engaged by a single lobe cam. The switching rocker arm assembly 10 can include an inner arm 22 and an outer arm 24. The inner arm 22 generally comprises a first inner side arm 22a, a second inner side arm 22b, an inner arm first end 22c, and an inner arm second end 22d. The outer arm 24 generally includes a first outer side arm 24a, a second outer side arm 24b, an outer arm first end 24c, and an outer arm second end 24d. The outer arm 24 further defines a latch hole 25 (FIG. 8).

  As will be understood from the discussion below, the inner arm 22 and the outer arm 24 can be locked together, thereby opening the engine valve and allowing the cylinder to operate as in a standard valve train. . As further shown in FIG. 8, the inner arm 22 can have a valve pad 26 disposed at the second end 22 d of the inner arm and configured to engage the valve 27. Inner arm 22 may further include a socket 28 disposed at inner arm first end 24 c and configured to receive ball plunger end 29 of DFHLA 12. The socket 28 and ball plunger end 29 may allow rotational degrees of freedom to move in all directions. This can enable a ball plunger end side and possibly an asymmetric load in certain operating modes.

  The DFHLA 12 has two fuel filler openings. The lower refueling port provides rush compensation and is supplied with engine oil similar to standard HLA. A top filler port, also referred to as a switching pressure port, provides a conduit between the controlled hydraulic pressure from the OCV and the latch assembly 32. The latch assembly 32 includes a latch pin 34 and a biasing member 36. When the latch pin 34 is engaged (extends outward along the latch hole 25), the inner arm 22 and the outer arm 24 together like a standard rocker arm for opening the engine valve. Operate. Inner arm 22 includes a rear stop 38 disposed at a first end 22 c of the generally inner arm configured to engage outer arm 24. In the non-lift (non-latching) position, the inner arm 22 and the outer arm 24 can move independently to allow cylinder deactivation. A further description of the operation of DFHLA 12 can be found in shared US Pat. No. 8,915,225, the contents of which are expressly incorporated herein by reference.

  First and second lost motion torsion springs 40 and 42 are incorporated to bias the position of inner arm 22 to maintain continuous contact with the camshaft lobe. With particular reference to FIG. 3, the first torsion spring 40 has a first leg 40a, a second leg 40b, and a coil portion 40c. The second torsion spring 42 includes a first leg 42a, a second leg 42b, and a coil portion 42c. The outer arm 24 has a first leg holding tab 44a and a second leg holding tab 44b. The first and second leg retaining tabs 44a, 44b are each substantially in the shape of a hook having respective extensions 44c, 44d. The inner arm 22 has a first finger part 46a and a second finger part 46b. The first leg 40a of the first torsion spring 40 engages the second leg holding tab 44b, while the second leg 40b of the first torsion spring engages the second finger 46b. doing. The first leg 42a of the second torsion spring 42 engages the first leg holding tab 44a, while the second leg 42b of the second torsion spring engages the first finger 46a. doing. Specifically, the first leg 40a is positioned between the first outer side arm 24a and the extension 44c, while the second leg 40b is the second outer side arm 24b and the extension 44d. It is positioned between. Inner arm first end 22c includes hubs 48a and 48b for receiving respective coil portions 42c and 40c.

  The inner arm 22 and the outer arm 24 are both attached to the pivot shaft 50. The pivot shaft 50 also allows a degree of rotational freedom to pivot about the pivot shaft 50 when the rocker arm assembly 10 is deactivated, while at the same time securing the inner arm 22 to the outer arm 24. It may be placed adjacent to the first end 52 of the assembly 10. A latch assembly 32 that selectively couples the inner and outer arms 22 and 24 is disposed on the opposing second end 54 of the rocker arm assembly 10. In addition to the illustrated example having separate pivot shafts 50 attached to the outer arm 24 and the inner arm 22, the pivot shaft 50 may be integral with the outer arm 24 or the inner arm 22. The rocker arm assembly 10 includes first and second inner side arms on the bearing shaft 64 that serve to transfer energy from the rotating cam to the rocker arm assembly 10 during normal operation of the rocker arm assembly 10. A bearing 60 having a roller 62 mounted between 22a and 22b may be included.

  The configuration of the switching rocker arm assembly 10 provides a compact design. In this regard, the first and second fingers 46a and 46b of the inner arm 22 and the first and second leg retaining tabs 44a and 44b are positioned intermediate the hubs 48a, 48b and the bearing 60. (Best shown in FIG. 5). Further, the latch assembly 32 and the first and second torsion springs 40, 42 are all installed at the same end of the inner rocker arm 22 (the first end 22c of the inner arm). Further, the second end 24d of the outer arm is not in front of the second end 22d of the inner arm, but provides a further packaging advantage, generally on the pivot shaft 50 in a direction generally opposite to the valve pad. Extend.

  The switching rocker arm assembly 10 allows variations in valve lift by inducing lost motion for one lift profile while simultaneously transmitting a secondary lift profile to the valve (or vice versa). Generally, the latch pin or connection mechanism is tightly controlled to minimize the effect on the gap on the valve lift. However, not all designs need to be tightly controlled, depending on the secondary valve lift application and purpose. In one such application, the clearance of the latch relative to the joining arm has no wider and more pronounced effect on the valve. Designs that can achieve this configuration have optimal requirements in the manufacturing process. It is also beneficial in view of better athletic performance, including further optimization of compactness, cost, and rocker arm parameter layout.

  The rocker arm assembly 10 achieves the main valve lift in the roller 60 and the valve lifts in the slider pads 80a and 80b due to the applied load cycle. The normal non-latching design is used to selectively use a secondary valve lift when required every engine load cycle. Inner arm 22 houses bearing 60 and roller 62, while outer arm 24 surrounds slider pads 80a and 80b within the cam joint area. A pivot shaft 50 connects the inner and outer arms 22, 24 and is disposed on the top of the engine valve. The inner arm 22 is mounted on the hydraulic lash adjuster 12 and joined to the ball socket region of the lash adjuster 12 by tangential contact (FIG. 8).

  The latch pin assembly 32 is positioned at the second end 54 of the rocker arm assembly 10 with the inner arm first end 22c extending outwardly away from the rocker arm assembly 10 for latching. Yes. In this regard, the latch pin assembly 32 is disposed on a common side as the springs 40 and 42. This configuration provides an improved packaging layout over prior art configurations. The rocker arm assembly 10 includes a compact design to improve kinematics. The rocker arm assembly 10 provides a reduced mass overvalve to improve kinematics. The main rocker event is the overroller design to optimize friction. The overall rocker arm packaging is optimized specifically for a given engine.

The foregoing description of the embodiments has been provided for the purposes of illustration and description. Also, it is not intended to be exhaustive or to limit the present disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but are applicable to each other, where applicable, and are not specifically shown or described. Even so, it can be used within selected embodiments. This may be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such variations are intended to be included within the scope of the present disclosure.

Claims (21)

A switching rocker arm,
An outer arm having a first outer side arm, a second outer side arm, a first end of the outer arm, and a second end of the outer arm, wherein the first outer side arm is a first leg. An outer arm having a retaining tab, the second outer side arm having a second leg retaining tab;
An inner arm pivotally fixed to the outer arm and having a latch hole, the inner arm comprising: a first inner side arm; a second inner side arm; a first end of the inner arm; An inner arm having a second end of the inner arm, the first end of the inner arm having a first finger, a second finger, a first hub, and a second hub;
A latch slidably connected to the inner arm at the latch hole and configured to selectively extend to engage the outer arm;
A roller and a bearing configured on the inner arm;
First and second lost motion torsion springs mounted on the respective first and second hubs and configured to bias the inner arm, the first and second lost Each of the motion torsion springs has a first leg and a second leg; (i) the first leg of the first lost motion spring engages the second leg retaining tab; The second leg of the first lost motion spring engages the second finger; and (ii) the first leg of the second lost motion spring is the first leg retaining tab. First and second lost motion torsion springs, wherein the second legs of the second lost motion torsion springs engage with the first fingers,
The first and second fingers of the inner arm, and the first and second leg retaining tabs are all positioned in the middle of (i) the first and second hubs and (ii) the bearing. Switching rocker arm.   And further comprising a slider pad configured on the outer arm, wherein the roller and the bearing cooperate to receive a main lift, and the slider pad is configured to receive a secondary lift. The switching rocker arm according to claim 1.   The switching rocker arm according to claim 1, wherein the latch and the first and second torsion springs are positioned at a first end of the inner arm.   The switching rocker arm of claim 3, wherein the inner arm further includes a socket disposed at a first end of the inner arm and a valve pad positioned at a second end of the inner arm.   A pivot shaft rotatably connecting the inner arm and the outer arm, the second end of the outer arm extending substantially above the pivot shaft in a direction generally opposite to the valve pad; The switching rocker arm according to claim 4.   6. The switching rocker arm of claim 5, wherein the socket is configured to receive a ball plunger end of a dual feed hydraulic lash adjuster.   The switching rocker arm of claim 1, wherein the inner arm further comprises a rear stop configured to selectively engage the outer arm.   The switching rocker arm of claim 1, wherein the first and second ends of both the first and second lost motion torsion springs do not engage the first end of the outer arm.   The switching rocker arm according to claim 1, wherein the first and second lost motion torsion springs have respective coil portions mounted on the respective first and second hubs.   The switching rocker arm according to claim 1, wherein the first and second leg retaining tabs are each in the form of a generally hook having a respective extension.   The first leg of the first lost motion spring is positioned between the first outer side arm and the extension of the first leg holding tab, while the second lost motion spring The switching rocker arm according to claim 10, wherein the second leg is positioned between the second outer side arm and the extension of the second leg retaining tab. A switching rocker arm,
An outer arm having a first outer side arm, a second outer side arm, a first end of the outer arm, and a second end of the outer arm, wherein the first outer side arm is a first An outer arm having a leg retention tab, the second outer side arm having a second leg retention tab;
An inner arm pivotally fixed to the outer arm and having a latch hole, wherein the inner arm is a first inner arm having a first inner side arm, a second inner side arm, and a socket. And a second end of the inner arm having a valve pad, the first end of the inner arm being a first finger, a second finger, a first hub, and a second hub Having an inner arm;
A latch slidably connected to the inner arm at the latch hole and configured to selectively extend to engage the outer arm;
A roller and a bearing configured on the inner arm;
First and second lost motion torsion springs mounted on the respective first and second hubs and configured to bias the inner arm, the first and second lost Each of the motion torsion springs has a first leg and a second leg; (i) the first leg of the first lost motion spring engages the second leg retaining tab; The second leg of the first lost motion spring engages the second finger; and (ii) the first leg of the second lost motion spring is the first leg retaining tab. First and second lost motion torsion springs, wherein the second leg of the second lost motion torsion spring engages the first finger;
A pivot shaft rotatably connecting the inner arm and the outer arm, the second end of the outer arm extending substantially above the pivot shaft in a direction generally opposite to the valve pad. A switching rocker arm comprising a pivot shaft.   The first and second fingers of the inner arm, and the first and second leg retaining tabs are all positioned in the middle of (i) the first and second hubs and (ii) the bearing. The switching rocker arm according to claim 12, wherein   And further comprising a slider pad configured on the outer arm, wherein the roller and the bearing cooperate to receive a main lift, and the slider pad is configured to receive a secondary lift. The switching rocker arm according to claim 12.   The switching rocker arm of claim 12, wherein the latch and the first and second torsion springs are positioned at a first end of the inner arm.   The switching rocker arm of claim 12, wherein the socket is configured to receive a ball plunger end of a dual feed hydraulic lash adjuster.   The switching rocker arm of claim 12, wherein the inner arm further comprises a rear stop configured to selectively engage the outer arm.   The switching rocker arm according to claim 12, wherein the first and second ends of both the first and second lost motion torsion springs do not engage the first end of the outer arm.   The switching rocker arm of claim 12, wherein the first and second lost motion torsion springs have respective coil portions mounted on the respective first and second hubs.   13. A switching rocker arm according to claim 12, wherein the first and second leg retaining tabs are each in the form of a generally hook having a respective extension. The first leg of the first lost motion spring is positioned between the first outer side arm and the extension of the first leg holding tab, while the second lost motion spring 21. The switching rocker arm of claim 20, wherein the second leg of the second leg is positioned between a second outer side arm and the extension of the second leg retention tab.