Three-roller rocker arm with cantilevered rollers and idle springs above valve or rocker arm pivot

Abstract

The invention provides a rocker arm which comprises a first outer arm, the first outer arm comprises a first inner side and a first outer side, and the first outer side comprises a first cantilever column. A first outer roller is mounted to the first cantilevered post. The second outer arm comprises a second inner side and a second outer side, the second inner side faces the first inner side, and the second outer side comprises a second cantilever column. A second outer roller is mounted to the second cantilevered post. A pivot body connects the first inner side to the second inner side. An actuatable latch mechanism is located within the pivot body. The inner arm assembly includes a latch arm that is pivotable adjacent to the pivot body. A pivot connects the inner arm assembly to pivot between the first outer arm and the second outer arm.

Description

[0001] This application is a divisional application of the invention patent application with application date of October 9, 2017, application number 201780069412.2, and invention name “Three-roller rocker arm with cantilevered roller and lost motion spring above valve or rocker arm pivot”. Technical Field

[0002] The present application provides a rocker arm for a valve train, the rocker arm comprising three rollers and a lost motion mechanism biased by at least one spring, wherein two rocker arms are cantilevered. Background Art

[0003] Biasing a rocker arm and its components against an attached actuator is difficult due to packaging constraints. Also, it is difficult to design a rocker arm for the countless possible lift curves because the moving parts tend to interfere with each other. Figure 1A In the prior art example of FIG. 1 , the through shaft 1 passes through the roller 2, the outer arm 3, the inner arm 4 and the roller shaft 6. The roller shaft 6 supports the roller 7. The spring biases the hollow roller shaft 6 in one direction so that when the latch mechanism is latched, the exhaust valve can have Figure 1B The exhaust valve curve shown in , or the intake valve may have Figure 1C The intake valve curve shown in . When not latched, it can be Figure 1B IEGR (Internal Exhaust Gas Recirculation) on the exhaust valve curve can be achieved in Figure 1C The difference in motion between the latched and unlatched curves is sufficient for some purposes, but the through-axis is restrictive for achieving other purposes. Summary of the invention

[0004] The methods and devices disclosed herein overcome the above disadvantages and improve the art by a rocker arm for a valve train, the rocker arm for a valve train comprising a body, the body comprising a pivot end, a valve end, a first outer side and a second outer side. A first column is connected to the first outer side and extends away from the first outer side. A second column is connected to the second outer side and extends away from the second outer side relative to the first column. A latch mechanism is located within the pivot end of the body, the latch mechanism comprising a latch finger, the latch finger being configured to selectively move between a latched position in which the latch finger extends toward the valve end and an unlatched position in which the latch finger is retracted away from the valve end, the latch comprising a latch surface. An inner arm assembly pivots between the first outer side and the second outer side from the valve end. The inner arm assembly comprises a latch arm, the latch arm being pivotable from a position above the latch surface to a position below the latch finger. A first roller is connected to rotate on the first column. A second roller is connected to rotate on the second column. At least one biasing mechanism biases the latch arm toward a position above the latch surface.

[0005] The at least one biasing mechanism may include a first spring mounted on the first outer side and a second spring mounted on the second outer side, wherein the first outer side may further include a first flange, wherein the second outer side may further include a second flange, wherein the first spring may be biased between the first flange and the shaft, and wherein the second spring may be biased between the second flange and the shaft.

[0006] The rocker arm may further include a pivot connecting the inner arm assembly to the body as the valve end, wherein the at least one biasing mechanism may be coiled around the pivot.

[0007] The rocker arm may further include a spring strut on the inner arm assembly between the pivot and the inner roller, wherein the at least one biasing mechanism may be biased against the spring strut.

[0008] The rocker arm may further include a valve seat for a valve assembly on the valve end, the valve seat being positionable between the first outer side and the second outer side, wherein the at least one biasing mechanism may be biased against the valve seat.

[0009] The valve seat may limit pivoting of the inner arm assembly.

[0010] The valve assembly may include a valve stem seated against the valve seat.

[0011] The rocker arm may also include a hydraulic lash adjuster mounted to the pivot end.

[0012] The latch arm may be configured to latch against the latch surface when the latch finger is in the latched position and may be configured to rotate past the latch finger when the latch finger is in the unlatched position.

[0013] The inner arm assembly may further include an inner roller rotatable on a bearing shaft. The rocker arm may further include a pivot connecting the inner arm assembly to the body. The latch mechanism may be in line with the pivot and the bearing shaft. The pivot and the bearing shaft may be in line in a first plane, and wherein the latch mechanism may be in a second plane inclined away from the first plane.

[0014] The valve train may include a rocker arm. The valve train may also include a set of three rotating cam lobes, the set of three rotating cam lobes being respectively configured to press on each of the first roller, the second roller and the inner roller, wherein the at least one biasing mechanism biases the inner roller toward the set of rotating cam lobes.

[0015] The valve train may include a rocker arm. The valve train may also include first, second and third rotating cam lobes, the first, second and third rotating cam lobes respectively configured to press on each of the first roller, the second roller and the inner roller, wherein the third rotating cam lobe is configured to selectively push the latch arm to rotate past the latch finger when the latch finger is in the unlatched position. The latch arm may be configured to latch against the latch surface when the latch finger is in the latched position and rotate past the latch finger when the latch finger is in the unlatched position.

[0016] Alternatively, the rocker arm includes a first outer arm, the first outer arm including a first inner side and a first outer side, the first outer side including a first cantilever column. A first outer roller is mounted to the first cantilever column. A second outer arm includes a second inner side and a second outer side, the second inner side facing the first inner side, the second outer side including a second cantilever column. The second outer roller is mounted to the second cantilever column. A pivot body connects the first inner side to the second inner side. An actuatable latch mechanism is located within the pivot body. The inner arm assembly includes a latch arm that is capable of pivoting adjacent to the pivot body. The pivot shaft connects the inner arm assembly to pivot between the first outer arm and the second outer arm.

[0017] The first cantilevered post may be integrally formed with the first outer arm, and wherein the second cantilevered post may be integrally formed with the second outer arm.

[0018] The rocker arm may further include a spring on the pivot and a valve tray between the first outer arm and the second outer arm, wherein the inner arm assembly may further include a spring strut, and wherein the spring may be biased between the valve tray and the spring strut. The spring may be biased to urge the latch arm over the actuatable latch mechanism.

[0019] The rocker arm may further include a first spring mounted on the first outer side and a second spring mounted on the second outer side, wherein the first outer side may further include a first flange, wherein the second outer side may further include a second flange, wherein the first spring may be biased between the first flange and the shaft, and wherein the second spring may be biased between the second flange and the shaft.

[0020] The latch arm may be adjacent to the pivot body, and wherein the pivot axis may be distal to the latch arm.

[0021] The inner arm assembly may be connected to the first outer arm and the second outer arm only via the shaft.

[0022] The rocker arm may further include a bushing that may be press fit to the first cantilever post to mount the first outer roller to the first cantilever post. The bushing may be a "T-shaped" bushing that includes an extension, and wherein the extension may provide travel limitation for the first outer roller. The rocker arm may further include a bearing located between the first cantilever post and the first outer roller to form a bearing assembly.

[0023] The rocker arm may further include a washer secured to the first cantilever post by a fastener, the washer facilitating rotation of the first outer roller on the first cantilever post.

[0024] The rocker arm may further include a valve seat distal to the pivot body. The valve seat may be integrally formed with the first outer arm and the second outer arm. The valve seat may be an insert on the pivot shaft and may be located within the inner arm assembly.

[0025] The inner arm assembly may include a rotatable bearing mounted on a bearing shaft. The rocker arm may also include a needle roller mounted between the bearing shaft and the rotatable bearing to form a needle roller bearing. The first cantilever column may be in line with the bearing shaft.

[0026] The first outer roller may include a central hole, and wherein the first roller may be mounted to the first cantilever column by inserting a fastener through the central hole and by securing the fastener to the first cantilever column. The first cantilever column may include a first column receiver, and wherein the first outer roller may be mounted to the first cantilever column by inserting a fastener through the central hole and into the first column receiver. The first receiver may be threaded, and wherein the fastener may be threaded. The rocker may also include a bushing located between the first outer roller and the first cantilever column. The first cantilever column may include an outer surface, and wherein the bushing may be mounted to the outer surface.

[0027] The type II valve train including the rocker arm may further include first, second and third rotating cam lobes, wherein the first cam lobe is configured to press against the first outer arm, wherein the second cam lobe is configured to press against the second outer arm, and wherein the third cam lobe is configured to selectively urge the latch arm to rotate past the actuable latch mechanism when the actuable latch mechanism is in an unlatched position. The inner arm assembly may be configured to be biased toward the third cam lobe by a spring force.

[0028] Additional 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 be learned by practice of the disclosure. These objects and advantages will also be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1A is a cross-sectional view of a prior art through-shaft rocker arm.

[0030] Figure 1B and Figure 1C is an illustration of a prior art valve lift curve for a through-shaft rocker arm.

[0031] Figure 2A and Figure 2B is a diagram of valve lift curves that may be achieved in addition to prior art valve lift curves when using the present disclosure.

[0032] Figure 3 A portion of a valve actuation system is shown.

[0033] FIG. 4A to FIG. 4G An alternative rocker arm view including an inner spring is shown.

[0034] FIG. 5A to FIG. 5E Alternative travel stop and roller configurations are shown.

[0035] FIG. 6A to FIG. 6E An alternative rocker arm view is shown including a spring on the pivot end.

[0036] 7A to 7F An alternative rocker arm view including an outboard spring on the valve end is shown.

[0037] FIG. 8A to FIG. 8D An alternative rocker arm view including an outboard spring on the valve end is shown.

[0038] Fig. 9A and Fig. 9B An alternative rocker arm view is shown including an outboard spring on the valve end and an alternative travel stop.

[0039] Fig. 10A and Fig. 10B An alternative valve seat insert is shown.

[0040] Fig.11 An alternative valve seat insert is shown.

[0041] Fig. 12A and Fig. 12B A comparison is made between a rocker arm in a valve train at base circle and a rocker arm when the inner arm assembly is fully actuated. DETAILED DESCRIPTION

[0042] Reference will now be made in detail to the examples illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0043] The rocker arm is subject to high actuation rates during valve raising and lowering. It is desirable to provide increased lost motion and enable early intake valve closing and other variable valve actuation, such as cylinder deactivation. However, prior art switching roller finger follower (SRFF) designs are constrained to either low lift events or high loss events, but cannot provide a range of lift events. Figure 1A A prior art SRFF corresponding to US 2015 / 0128890 is shown, which has a limited range for variable valve lift (VVL) events. Figure 1A The SRFF can achieve a conventional exhaust valve curve and a conventional intake valve curve. Using a latch, the SRFF can be switched to provide Figure 1B Internal exhaust gas recirculation (IEGR) or Figure 1C The delayed intake valve closing (LIVC) curve in Figure 1A In FIG. 1 , the motion of the exemplary SRFF is limited by the central through-shaft 1. By eliminating the through-shaft 1, a greater range of motion can be achieved.

[0044] For example, Figure 2A An early intake valve closing (EIVC) curve can be achieved using the SRFF disclosed herein. Three eccentric cam lobes, two outer cams 1001 and 1002, and an inner cam 1003 can rotate on a cam track 1000 of a Type II engine valve train. The actuator for the SRFF may include an electromechanical latch or a cam lobe. The rocker arm can be installed in a Type II overhead cam valve train with one or more cam guides. Alternatively, other actuation tracks can be implemented for a cam / camless system with some cam operation and some operation without a cam. Each roller 400, 410, 310 of the rocker arm (SRFF) may correspond to a cam lobe or other actuator.

[0045] The shape of the cam lobes 1001, 1002, 1003 determines the movement of the SRFF when the latch mechanism 900 within the pivoting body 111 is selectively actuated. Fig. 12AAs shown, the rocker arm latches when the cam 1003 is on base circle, which can cause the valve to close. However, controlling the hydraulic fluid through the hydraulic lash adjuster (HLA) 3000, such as through fluid ports 3001, 3002, can actuate the latch mechanism 900, causing the latch finger 906 to retract and allowing the inner arm assembly 20911 to swing downward when the peak of the eccentric portion of the cam lobe 1003 presses against the roller 310. The HLA or similar mechanism can connect the SRFF to the engine cylinder block at the pivot end 11 of the SRFF. In addition or alternatively, a push rod can be connected to the HLA 3000. The valve end 12 of the SRFF may include a valve seat in the form of a valve tray 112, or one of the alternatives herein, for mounting the valve stem end 2001 of the valve so that the valve head 2003 can be opened and closed to provide the desired valve curve. For example, when the SRFF is latched, it can be achieved Figure 2B The high lift curve shown in . The inner cam lobe 1003 can be designed to have a greater cam lift (in millimeters) than the outer cams 1001, 1002. The eccentricity of the cams can be designed so that as the cam lobes rotate (expressed as cam angles in degrees) away from their base circle, the valve head 2003 can open and close according to one or more of different timings, durations, and degrees. Figure 2B , the outer cam angles 1001, 1002 are designed to have a smaller cam lift than the inner cam angle 1003. When the SRFF is unlatched, the inner cam angle 1003 pushes the inner roller 310 connected to the inner arm 200, 210, and the outer cam angles 1001, 1002 push the outer rollers 400, 410 to produce a low lift curve. The incremental curve shows the difference between the high lift curve and the low lift curve. The height of the incremental curve can be related to the relative movement of the inner arm of the SRFF and can indicate the idle stroke of the inner arm. The lift event of the high lift event may be much higher than that of the prior art. Approximately 30% more lift can be achieved using the arrangement disclosed in the present invention. And, by pairing the SRFF disclosed in the present invention with the appropriate cam lobes, the same SRFF can be used to implement prior art devices (such as Figure 1B and Figure 1C )’s lift curve.

[0046] Figure 2A and Figure 2B is an exemplary lift curve. Other lift curves are possible and are not drawn exhaustively. The rocker arm may include three rollers: 400, 410, 310. The two outer rollers 400, 410 are mounted in cantilever fashion outside the rocker arm to rotate on posts 123, 133 on the outer arms.

[0047] The third roller (inner roller) 310 can be mounted on an independent bearing shaft (such as the second shaft 300) between the inner arms 220, 230. The inner arms 220, 230 can pivot on a pivot (such as the first shaft 302). The pivot can connect the inner arm assembly 209 to the distal end of the outer arms 120, 130. The first shaft 302 as a pivot can also connect at least one biasing mechanism, the center spring 509, to the rocker arm.

[0048] When the inner arm assembly 209 pivots on the pivot, "lost motion" is said to occur, and the inner arms 200, 210 can pivot to allow variable valve lift events from zero valve lift (full cylinder deactivation or full lift loss) to some amount less than full lift. Alternatively, the inner arm can be locked via a latch seat to allow high lift events greater than normal lift events, while normal lift events occur on the rollers of the outer arm.

[0049] This enables technologies such as cylinder deactivation (CDA) (valve closing) and valve advance or retardation technologies including negative valve overlap (NVO), early or late intake valve opening or closing (EIVC, LIVC, EIVO, LIVO) or early or late exhaust valve opening or closing (EEVO, EEVC, LEVO, LEVC).

[0050] Thus, the SRFF (sometimes referred to as a rocker arm) can be designed for variable valve lift events or for cylinder deactivation (CDA). In a first engine operating mode, the inner cam lobe 1003 presses against the inner roller 310 housed between the inner arms 200, 210 of the rocker arm. The latch is biased or actuated to snap onto the latch seat connected to the inner arm so that the cam lobe pushes the inner arms 200, 210 and the outer arms 120, 130 of the body 110 of the rocker arm. This creates a first lift height for the attached valve. Then, during a second engine operating mode, when the inner cam lobe 1003 presses against the inner roller 310, the latch can move away from the latch seat to allow the inner arms 200, 210 to pivot. The lift height of the inner cam lobe may be "lost" because it is not transmitted to the valve. The outer cam lobes 1001, 1002 can press against the outer arms 120, 130 of the rocker arm to achieve a second lift height. The second lift height may be from zero to some amount less than the first lift height.

[0051] Go to FIG. 4A to FIG. 4G In the first exemplary SRFF, there is no longer a through shaft 1 across the three rollers 2, 7. The middle or inner roller 310 can now be a single shear material instead of a double layer of material. Figure 1A The outer rollers 400, 410 are cantilevered from the SRFF body, rather than Figure 1AAs shown, the through shaft 1 slides through the outer arm, and the outer rollers 400, 410 can be mounted on cantilevered posts 123, 133 formed integrally with the outer arms 120, 130. By using rollers 400, 410, 310 instead of slider pads, friction losses can be reduced. By cantilevering the outer rollers 400, 410 out of the SRFF body, large lift events can be accommodated. The inner arm assembly 209 can move independently of the outer arms 120, 130. The inner arm assembly 209 can include the inner arms 200, 210, the latch arm 220 and the inner rollers 310, as well as additional features and alternatives outlined below.

[0052] FIG. 4A to FIG. 4G An alternative view of an SRFF is shown with a lost motion spring 509 located above the valve end of the body 110 and cantilevered outer rollers 400, 410. The latch mechanism 900 for the center lost motion mechanism is in line with the main profile of the SRFF. By viewing Figure 4D The planar cross-section of can be understood as a straight line shape, where the straight line shape is the result of the coplanar relationship of the first axis 302 (pivot) connecting the inner arm 220, 230 to the outer arm 120, 130, the bearing (or second) axis 300 and the main axis of the latch mechanism 900.

[0053] The center spring 509 is located above the valve end of the rocker arm. The valve end 2001 can be mounted adjacent to the second side 114 of the valve tray 112. The valve guide 115 can be formed on the valve tray 112 in the form of a protrusion that guides the valve stem end 2001 when the SRFF is rocked during actuation. The valve guide can be hooked or clamped to hold the valve stem end 2001. The valve guide 115 limits the left and right movement of the valve stem end 2001 against the valve tray 112, while not limiting the ability of the valve stem end to slide forward and backward along the second side 114 of the valve tray. That is, the valve stem 2000 can move slightly in a direction parallel to the long axis AA of the SRFF, but is restricted from moving perpendicular to the long axis of the SRFF. At the same time, the hydraulic lash adjuster (HLA) 3000 can be installed in the HLA seat 117 in a ball and socket type arrangement to cooperate with the hydraulic port 116.

[0054] The center spring can be biased in a variety of ways. For example, the first end 5001 of the center spring 509 can be biased against a spring strut in the form of the inner rod 204. The second end 5002 of the center spring 509 can be biased against the first side 113 of the valve tray 112. Alternative biasing techniques will be discussed below.

[0055] exist 4A to 4D, the latch mechanism 900 is in the latched position. The center spring biases the inner arm assembly 209 so that the inner roller 310 is lifted toward the inner cam lobe 1003 when the SRFF is installed in the valve train. This can also mean that the latch arm 220 is biased to a position above the surface of the latch assembly 900, such as above the latch support 901. Therefore, when the inner arm assembly 209 is pressed from above, the latch arm 220 of the inner arm 200 can contact the latch support 901, or the latch arm 220 can be biased to a position slightly above the latch support 901.

[0056] exist Figure 4E and Figure 4F , the latch mechanism 900 is in the unlatched position and the latch arm 220 has been rotated past the latch to allow the central cam lobe 1003 to “freewheel” on the inner arm assembly 209. The outer cam lobes 1001, 1002 can roll on the outer first roller 400 and the outer second roller 410.

[0057] The latch mechanism 900 may be actuated by hydraulic means and thus connected to an oil-controlled valve and oil-controlled circuit. Alternatively, an electric or electromechanical mechanism may reciprocate the latch. The latch may be biased to operate in a default position or require positive control of each of the first position or the second position (extended position or retracted position).

[0058] exist 4A to 4F In the example of FIG. 1 , a hydraulic latch for a latch mechanism 900 is shown. The latch finger 906 can reciprocate so that the latch support 901 can extend from and retract to an inner latch port 118 in the pivoting body 111 of the SRFF. The latch finger 906 can be in fluid communication with the hydraulic port 116 so that fluid can be supplied through the HLA 3000 or through the latch fluid port 905, or a fluid circuit can be established therethrough. The latch port 118 is stepped, like the latch finger 906, so that when the latch finger 906 is extended, the shoulder can fill a portion 1190 of the latch cavity; and when the latch finger 906 is retracted, the shoulder can fill another portion 1191 of the latch cavity. The latch plug 904 can receive and bias a latch spring 902, which can bias the latch finger 906 to an extended position. As discussed above, other latching mechanisms may be substituted for the hydraulic latch shown without departing from the principles of operation of the SRFF described herein.

[0059] Figure 4C and Figure 4DAdditional aspects are shown. The inner roller 310 can be a single material, or it can include a separate bearing shaft or second shaft 300 and an outer material fixed across the inner arms 220, 230, as shown. In some embodiments, the bearing shaft 300 can be surrounded by bearings (such as, ball or needle bearings 312), and the outer material is used as an outer race and a bearing surface for engaging with the cam lobes 1003. In either case, a hollow passage 313 can be formed in the inner roller 310. The hollow passage can allow for lightweight or other weight control techniques. When combined with the aspects below, the hollow passage can be used with an alignment tool to set the placement of an evacuation stop (such as a pin 700).

[0060] Figure 4E and Figure 4F The SRFF is shown in an unlatched state. The latch finger 906 is in a retracted position and the shoulder of the latch finger is retracted to allow flow in the other cavity 1191 of the stepped inner latch port 118. As described above, the center spring 509 is biased between the spring post 204 and the first side of the valve tray 113. However, the inner cam lobe 1003 can overcome the spring force of the center spring 509. When the inner arm assembly 209 pivots on the first axis 302, the latch arm 220 can swing past the latch mechanism 900, but because the inner arm can contact the first side 113 of the valve tray 112, the inner arms 200, 210 cannot swing past the valve tray 112. Therefore, the range of travel of the inner arm assembly 209 can be limited by the evacuation stop (such as the pins 700, 701, 703) in the first direction and the valve tray 112 in the second direction.

[0061] although FIG. 4A to FIG. 4G The examples show a straight latch, but other examples show alternative designs with an angled latch mechanism 900 for a center lost motion mechanism (inner arm assembly 209). The angled latch can include a pivot axis (first axis 302) and the inner arm first axis 300 being straight in a plane (intersecting the plane), and the latch mechanism 900 can be tilted away from the plane (the latch mechanism 900 can be in the intersecting plane). FIG. 4A to FIG. 4G In the example, the lost motion spring is located inside the body of the SRFF, and the lost motion spring biases the inner roller 310 toward the cam track 1000. The lost motion spring 509 is positioned above the valve. However, in other examples, the lost motion spring or springs are in a different location, but continue to bias the inner roller 310 toward the cam track 1000 or toward a position above the latch finger 906.

[0062] Pivot side lost motion spring

[0063] exist FIG. 6A to FIG. 6E, another alternative is shown in which the lost motion spring is above the pivot end 11 of the SRFF. The inner arm assembly 2096 may include inner arms 200, 210, a latch arm 220, and an inner roller 310. The inner roller may be between the inner arms 200, 210, and may include a portion of the bearing shaft 300 extending through the inner arms 200, 210 toward the outer arms 120, 130. The lost motion spring is located above the hydraulic lash adjuster (HLA) 3000 or push rod, and in this embodiment, the lost motion spring is not located above the valve end 12. Therefore, there is less weight above the valve, which enhances the favorable valve train dynamics. Valve operation is more optimized. In addition, two lost motion springs are located on the sides of the latch mechanism 900 to replace a single lost motion spring in the center of the SRFF.

[0064] The lost motion spring is a pivot side spring 5010, 5020 mounted to a spring post 1131, 1141 on the pivot body 111 on the pivot end of the rocker arm. A spring bushing 5040 may be pressed onto each spring post 1131, 1141 to secure the pivot side spring 5010, 5020 in place. The body 110 may include a first flange and a second flange, such as a pivot flange 1111, 1121, for biasing the first spring arm end 5011, 5013. The second spring arm end 5021, 5023 may be biased against the bearing shaft 300 (which may be integrally formed with the inner roller 310). The bearing shaft 300 may extend from the inner arm 220, 230 to abut against the second spring arm end 5021, 5023.

[0065] This arrangement allows for straight arms on the spring for the spring arm ends 5011, 5013, 5021, 5023. Additionally, the "kidney box" of prior designs is eliminated, where the bearing shaft previously passed through the outer arm and limited the range of travel of the inner arm. The outer arm may include a bend 1201, 1301 in the outer arm 120, 130, while the inner arm 210, 220 is straight. Another alternative may be appreciated by observing the evacuation stop, and FIG. 6A to FIG. 6E The arrangement may include Figure 4G as well as FIG. 5A to FIG. 5E The pins 700 , 701 , 703 are arranged with means for abutting against the second spring arm ends 5021 , 5023 .

[0066] With a lost motion spring on the pivot end of the SRFF, the inertia above the valve is reduced and valve actuation can be faster. Additional lightening on the valve side can be achieved by removing the spring strut 204.

[0067] exist Fig. 6A , Figure 6B and Fig. 6E , the rocker arm is shown in the latched position, while Figure 6C and Fig.6DThe inner arm is shown pivoted away from the latch mechanism when in the unlatched position. The travel of the inner arm assembly 209 may be limited by one of the travel limiting techniques herein, such as the pump-down stop technique below, or such as limited by the valve tray 112 as above.

[0068] in addition, FIG. 6A to FIG. 6E The spring can be constructed in a straight line on the side above the pivot, such as Fig. 6E As shown, the plane can intersect each of the first axis (pivot axis) 302, the bearing axis 300, and the long axis of the latch mechanism 900. Alternatively, an angled latch configuration can be used so that the first plane can intersect each of the first axis (pivot axis) 302 and the bearing axis (second axis) 300, while the long axis of the latch mechanism 900 is in a separate plane that intersects the first plane.

[0069] Thus, a rocker arm for a valve train may include a body 110 including a pivot end 11 and a valve end 12. Outer sides 121, 131 may constitute a first side and a second side. A first column 123 may be connected to the first side 121 by being integrally formed with the first side, and the first column 123 may extend away from the first side 121. A second column 133 may be connected to the second side, and may extend away from the second side opposite to the first column 123. A first roller 400 may be connected to rotate on the first column 123, and a second roller 410 may be connected to rotate on the second column 133. The first column 123 and the second column 133 may be cantilevered from the outer sides 121, 131.

[0070] The latch mechanism 900 can be located within the pivot end 11 of the body 110. The latch mechanism 900 can include a latch finger 906 configured to selectively move between a latched position (where the latch finger 906 extends toward the valve end 12) and an unlatched position (where the latch finger 906 is retracted from the valve end 12). The latch finger 906 can include a latch surface 901.

[0071] The latch arm 220 of the inner arm assembly 209 can be pivoted from a position above the latch surface 901 to a position below the latch surface 901 between the first side and the second side of the valve end 12. The inner arm assembly 209 can include a shaft 300 and a third roller, an inner roller 310, rotatable on the shaft 300. The latch arm 209 can be configured to latch against the latch surface 901 when the latch finger 906 is in the latched position, and configured to rotate past the latch surface 901 when the latch finger 906 is in the unlatched position.

[0072] There are further alternatives for biasing the latch arm of the inner arm to a position above the latch seat 901 of the latch finger 906. Biased in this direction, the inner roller 310 can follow the cam lobe 1003 for actuation in the valve train.

[0073] Outer lost motion spring

[0074] Go to 7A to 9B , an alternative outboard spring design is proposed, in which the spring is mounted on the valve end 12 of the rocker arm. By switching from the inner coil spring 509 to an outboard alternative, the springs 506, 507, 5060, 5070 can be mounted on the outside of the rocker arm to avoid interfering with the sweep of the inner cam lobe 1003.

[0075] exist 7A to 7F In FIG. 1 , an alternative integral torsion spring is shown. The ends of the alternative spring react against the outer sides 121 , 131 of the outer arms 120 , 130 , and the alternative spring also reacts against the extensions on the inner arms 200 , 210 . FIG. 8A to FIG. 9B In the embodiment of the present invention, two springs 5060, 5070 are used, which have alternative arrangements for reacting the ends against the outer (external) side 121, 131 of the outer arm, and for reacting the ends against alternative extensions on the inner arm.

[0076] The rocker arm may include a first spring flange 129 and a second spring flange 139. The flanges 129, 139 may be positioned longitudinally between the pivot 302 and the first (inner) roller 310 or the outer roller 400, 410. A spring 500 may be mounted on the first shaft 302. The spring 500 may be biased against the flanges 129, 139. 7A to 7F The integrated spring 500 may include a first spring 506 mounted on the first outer side 121 and a second spring 507 mounted on the second outer side 131. The first spring 506 and the second spring 507 may be torsion springs whose tangential spring ends extend at approximately 90 degrees. The transverse connector 505 may connect the first spring 506 to the second spring 507. The first spring 506, the second spring 507, and the transverse connector 505 may be integrally formed to manufacture the integrated spring 500. The first spring 506 may include a flange end 501 abutting the flange 129, and the second spring 507 may include a flange end 502 abutting the flange 139.

[0077] The transverse connector 505 can react (be biased by) extensions on the inner arms 200, 210, such as corresponding hook-shaped spring legs 201, 211. The first spring leg 201 on the first inner arm 200 is distal to the latch arm 220. The second spring leg 211 on the second inner arm 210 is distal to the latch arm 220. When the cam lobe 1003 causes the inner arm assembly 209 to pivot, the transverse connector 505 is pressed by the spring legs 201, 211, and the force is transferred to the coils of the springs 506, 507. Fig. 7EAs shown, the inner arm assembly 209 can be swung to allow free play. 7A to 7F The SRFF may achieve a greater amount of lost motion than previous embodiments. In addition, the stress of contacting the valve tray 112 is removed from the SRFF and valve train system.

[0078] When the cam lobe 1003 rotates from the eccentric edge of the inner roller 310 to the base circle of the inner roller, the springs 506, 507 expand, which abut against the first spring flange 129 and the second spring flange 139 and against the spring pillars 201, 211 to bias the inner arm assembly 209 toward the latched state again, wherein the latch arm 220 is above the latch support 901, as shown in FIG. Figure 7C and Fig.7D shown.

[0079] The hook-shaped spring struts 201, 211 may be integrally formed with the inner arms 200, 210 and may include additional material for guiding the valve stem end 2001, such that the valve tray 112 is no longer required. The scalloped inner arm valve guides 240, 241 may be formed on the inner arms 200, 210 to flank the valve stem end 2001. Lateral movement of the valve stem end 2001 is thus limited, but a small amount of sliding along the long axis of the SRFF on the crown of the valve seat insert is permitted. A variety of valve seat inserts 600, 601, 602 may then be accommodated, corresponding to the teachings below. By properly securing the inner arms 200, 210 between the outer arms 120, 130, the inner arms 200, 210 may exert a clamping force on one or both of the valve stem end 2001 and the valve seat insert to hold the items in place. The commonality of the pivot 302 on the valve end 12 promotes efficient use of components, thereby unifying the outer arm, inner arm and valve seat insert by a single operation of inserting the pivot. The outer arm, inner arm, valve seat insert and springs 506, 507 can also be unified by a single operation of inserting the pivot 302.

[0080] Replacement rocker arm FIG. 8A to FIG. 8D 302. These figures include separate springs 5060, 5070 mounted to the pivot 302. The springs 5060 and 5070 can be torsion springs with tangential spring ends extending at approximately 90 degrees. The slim design allows the straight inner arms 200, 210 to be located within the substantially straight outer arms 120, 130 to achieve a compact footprint. Also, the latch assembly 900 can be laterally constrained to fit between the outer (outer) sides 121, 131 of the outer arms 120, 130 to achieve a slim design. As described above, the latch arm 220 can pivot between the outer arms 120, 130.

[0081] Fig. 7A , Fig. 8A and Figure 8CThe top view of shows that the springs 506 and 507 or 5060 and 5070 need not extend laterally past the outer rollers 400, 410. The outer (outer) side 121, 131 of the outer arm may be stepped to provide a groove or dimple for the springs 5060, 5070. Such a groove or dimple may also be provided for the springs 506, 507 described above. The springs may then be withdrawn laterally into the rocker arm and the valve seat with the spring ends 501, 502 or 5010, 5020 pressed against the flanges 129, 139. The flanges 129, 139 may form the surface of the groove or dimple and be part of the stepped shape of the outer side 121, 131. The flanges 129, 139 may be positioned longitudinally between the pivot 302 and the rollers 310, 400, 410.

[0082] exist Fig. 8A and Figure 8B In the embodiment of the present invention, the inner arm assembly 2099 may include inner arms 200, 210 having forward spring struts 202, 212, latch arms 220, and inner rollers 310. Spring ends 503, 504 react against laterally extending spring struts 202, 212, while spring ends 5010, 5020 react against flanges 129, 139 on outer sides 121, 131 of outer arms 120, 130. Fig. 8A and Figure 8B 1, transversely extending spring legs 202, 212 extend from the inner arms 200, 210, and the spring legs 202, 212 are located in front of the valve seat insert 602. The first spring leg 202 on the first inner arm 200 is distal to the latch arm 220. The second spring leg 212 on the second inner arm 210 is distal to the latch arm 220. The spring legs 202, 212 are the farthest sides on the valve end 12. The spring legs 202, 212 can extend so that they protrude from between the outer arms 120, 130. The inner arm valve guides 240, 241 can be included to function as described above, and the transverse spring legs 202, 212 can protrude therefrom.

[0083] exist Figure 8C and Fig.8D In the spring 5060, 5070 from Fig. 8A and Figure 8BThe position shown is rotated, and so are the angles of the flanges 129, 139 and the positions of the spring legs 202, 212. The inner arm assembly 20910 can include an inner arm 200, 210 with an alternative spring leg position, a latch arm 220, and an inner roller 310. The laterally extending spring legs 202, 212 can be located behind the valve seat insert 602, or can intersect a plane passing through the valve seat insert. The spring legs 202, 212 can still be considered to be on the far side of the latch arm 220. The spring legs 202, 212 can be in line with the pivot 302. Alternatively, the spring legs 202, 212 can be positioned more centrally (closer to the center of the rocker arm). The spring legs 202, 212 are shown as having a notch 222 for seating the spring ends 503, 504. Likewise, the spring legs 202, 212 can extend so that they protrude from between the outer arms 120, 130. Inner arm valve guides 240, 241 may be included to function as described above, and transverse spring struts 202, 212 may project therefrom. Figure 8C and Fig.8D The embodiment may be such that if the inner arm assembly 209 rotates enough to cause contact between the spring struts 202, 212 and the outer arms 120, 130, the lateral spring struts 202, 212 act as inner arm assembly travel stops. Figure 8C and Fig.8D In the embodiment, an outer arm connector 145 can be included on the valve end of the outer arm to provide stability.

[0084] exist Fig. 9A and Fig. 9B Another example of providing a travel stop on the outer arms 120, 130 can be seen in FIG. The inner arm assembly 20911 can include an inner arm 200, 210 having a hook spring post 201, 211, a latch arm 220, and an inner roller 310. The outer arm connector 145 can include a piece of material extending from one or both outer arms toward the other outer arm. The outer arm connector can provide structural stability when integrally formed or integrally connected to the outer arms 120, 130. When in the latched state, the inner arm assembly 209 is restricted from pivoting too far in the direction of the cam track 1000, and the latch arm 220 can now only travel in the direction above the latch seat 901 because the spring post (here the hook spring post 201, 211) contacts the outer arm connector 145. The integral spring 500 biases the spring post 201, 211 in the direction of the outer arm connector 145. The inner arm valve guides 240, 241 may be appropriately shaped to rotate between the outer arms 120, 130 and the outer arm connector 145. In the unlatched state, the spring legs 201, 211 travel away from the outer arm connector 145.

[0085] exist Fig. 12A and Fig. 12BIn the embodiment, the outer arm connector 145 can provide an alternative function. Fig. 12A In the latched state, the valve seat insert 600 is "buckled" by the outer arm connector 145 to be located within the rocker arm and prevent it from falling out. Fig. 12B , the outer arm connector 145 abuts the inner arm valve guide 240 to provide a travel stop for the inner arm assembly 20911.

[0086] Valve Seat Inserts

[0087] Another aspect of the outer arm connector 145 can be understood with respect to the valve seat insert 600 (sometimes referred to as an e-foot or elephant foot). In this embodiment, the valve seat insert 600 can include an "L" shape. The outer arm connector 145 can provide travel restrictions for the valve seat insert 600, such as by providing a flange on which the upper lip 6003 can snap. The valve seat insert 600 can be extruded from the inner arm 200, 210 and can be molded to conform to at least a portion of the pivot 302. The inner arm valve guides 240, 241 can be located on the sides of the valve surface 6002 to collectively provide a valve seat for the valve stem end 2001. In some cases, a hook, cleat, or step can be included on the inner arm valve guides 240, 241, similar to the valve guide 115, to secure the valve stem end 2001. The valve seat insert can be inserted between the lost motion springs 506, 507 to increase cross-sectional stiffness.

[0088] Go to Fig.11 , the valve seat insert 600 can be constrained between a first inner surface of the inner arm 200, a second inner surface of the inner arm 210, the outer arm connector 145, and the pivot shaft 302. The valve seat insert 600 can include a crowned valve surface 6002. To be "crowned," the valve surface 6002 can include a curvature so as not to be completely flat. The valve seat insert 600 can include an outer leg 6007 and an inner leg 6009. The outer leg can include an upper lip 6003 configured to catch on the outer arm connector 145 when the latch arm 220 is pivoted to a first position, such as a latched position. The valve seat insert 600 can include a lower lip 6005 configured to catch on the outer arm connector 145 when the latch arm 220 is pivoted to a second position, such as an unlatched or idle position. The inner leg can include an inner knob or knurl 6006 configured to curl around a portion of the shaft 602. The valve seat may include an axis groove 6001 for placing the structure flush with the first axis (pivot) 302.

[0089] Go to Fig. 10A and Fig. 10B , and review FIG. 7C to FIG. 7F as well as Fig.8DIn various aspects of the present invention, alternative valve seat inserts 601, 602 will be discussed. With the valve seat insert 601 or 602, there is no need to "basket" the valve seat insert via the outer arm connector 145, so the outer arm connector 145 can be omitted. To facilitate this, the valve seat insert 601 or 602 can be constrained between the first inner surface 250 of the inner arm 200, the second inner surface 251 of the inner arm 210, and the pivot 302. The valve seat insert 601 or 602 can include a front tip 6013 configured to surround a portion of the pivot 302 and a rear tip 6014 configured to surround a second portion of the pivot 302. The valve seat insert 601 or 602 can be suspended from the pivot 302 via the front tip and the rear tip. This design allows the valve seat insert to be clamped on the pivot, or allows the assembly method of inserting the pivot to unify the outer arm, inner arm, valve seat insert, and spring. A valve seat insert may be inserted between the lost motion springs 506, 507 or 5060, 5070 to increase cross-sectional stiffness.

[0090] The valve seat may also include a valve seat body 6010 joined to a front tip 6013 and a rear tip 6014. The valve seat body may be cuboidal such that it resembles a cube or is approximately in the shape of a cube.

[0091] The valve seat body may be flat or may include a crowned valve surface 6012. The valve seat body may include a shaft groove 6011 for seating the valve seat flush with the shaft.

[0092] FIG. 7C to FIG. 7E , Fig. 8A , Figure 8B The valve seat insert 602 does not include a valve guide for limiting lateral movement of the valve stem end 2001, so in some cases, a hook, clamp or step can be included on the inner arm valve guide 240, 241, similar to the valve guide 115, to laterally fix the valve stem end 2001. Alternatively, although the inner arm valve guide 240, 241 can be relied upon to limit lateral valve stem end movement on the e-foot, Figure 7F and Fig. 10B A valve seat insert 601 is shown including a first valve guide 6015 and a second valve guide 6016. The first valve guide 6015 and the second valve guide 6016 can extend away from the valve seat body 6010, and the first valve guide and the second valve guide are configured to constrain the valve stem end 2001. Then, the inner arm 200, 210 can be lightweight by removing the valve guides 240, 241. Therefore, 7A to 7E The inner arm assembly 2097 may include inner arms 200, 210, latch arms 220 and inner rollers 310, wherein the inner arms 200, 241 include inner arm valve guides 240, 241. However, in Figure 7FIn the embodiment, the inner arm assembly 2098 may include the inner arms 200, 210, the latch arm 220 and the inner roller 310 without the inner arm valve guides 240, 241. The inner arm assemblies 2097 and 2098 may both include hook-shaped spring struts 201, 211.

[0093] The rocker arm may include various mechanisms for holding the valve stem 2000 for actuation. The valve seat may be distal to the pivot body 11. A first example of a valve seat is a valve tray 112, which may be integrated or integrally formed between the outer arms 120, 130. The valve tray 112 may include a first side 113 for a biasing spring and a second side 114 for receiving the valve stem end 2001. When the cam lobes 1001, 1002, 1003 press against the rocker arm, the rocker arm pivots from the pivot body 111, tilting the rocker arm and pushing the valve tray 112 toward the cylinder. By comparison Fig. 12A and Fig. 12B This tilt can be seen. The second side 114 of the valve tray 112 may include a crowned surface so that it is not completely flat and the valve stem end 2001 may slide slightly on the crowned surface. A valve guide 115 may extend downwardly from the valve tray to inhibit valve stem movement. The valve tray 112 may limit the range of motion of the pivoting inner arms 200, 210.

[0094] Alternatively, the valve seat may include a valve seat insert 600, 601, 602 that can be retained in the rocker arm. One design includes a valve guide formed on the inner arm 200, 210. The valve guide 240, 241 can be an extension of the inner arm, such as a scalloped or other ridge or knurl. Alternatively, the valve guide 240, 241 can include a hooked end or clamp for clamping the valve stem end 2001. When the inner arm 200, 210 is installed between the outer arms 120, 130, the first shaft 302 constrains the valve seat insert from the top. When hooked or clamped, the valve guide constrains the valve guide insert from the bottom, and the inner surface 250, 251 of the inner arm constrains the valve guide insert from the side. The valve seat is constrained between the inner arms 200, 210 rather than between the outer arms 120, 130, thereby creating a greater range of motion for pivoting the inner arm assembly 209.

[0095] The rocker arm includes a first outer arm 120, which includes a first inner side 122, a first outer side 121, a first end 1201, and a second end 1202. The second outer arm 130 includes a second inner side 132, a second outer side 131, a third end 1303, and a fourth end 1304. The pivot body 111 connects the first end of the first outer arm to the third end of the second outer arm. The outer arm connector 145 can span between the second end of the first outer arm and the fourth end of the second outer arm. The actuatable latch mechanism can reciprocate within the pivot body.

[0096] The first inner arm 200 includes a first inner surface 250 and a first outer surface 260. The second inner arm 210 includes a second inner surface 251 and a second outer surface 261. The latch arm 220 may be located between the first inner arm and the second inner arm, and the latch seat may pivot adjacent to the pivot body 111 so as to swing past the latch mechanism 900 within the pivot body 111. The latch mechanism 900 may include a latch finger 906 that may reciprocate, retract to release the latch seat 901 from the latch arm 220 proximate to or against the inner arms 200, 210, or extend to abut the latch seat 901 to the latch arm 220 and prevent significant movement of the inner arms.

[0097] The first shaft 302 may connect the first inner arm 200 and the second inner arm 210 to pivot between the first outer arm 120 and the second outer arm 130. The first outer surface 260 abuts the first inner side 122, and the second outer surface 261 abuts the second inner side 132.

[0098] Pump-out stop

[0099] In order to obtain controlled valve train dynamics at high speeds, the lost motion springs 500, 5000, 506, 507, 5060, 5070 on the switch roller finger followers (SRFF) must have sufficient stiffness. When this stiffness is reached, it often produces a force greater than the hydraulic lash adjuster (HLA) 3000, which will cause the HLA to "pump out". Non-hydraulic lash adjusters may be stretched by the springs. These are undesirable results of spring design. Therefore, travel stops can be designed into the SRFF, such as those disclosed above and the subsequent pump out stop pins 700, 701, 703.

[0100] Pump-out stop pins 700, 701, 703 provide hydraulic lash adjuster pump-out stop protection. These designs solve the pump-out problem of three-roller rocker arm designs in a unique way. Figure 4G and FIG. 5A to FIG. 5E Various alternatives are shown.

[0101] Although a three-roller rocker arm has been described, sometimes a slide (such as a pad or other sliding surface) may be used in place of rollers 400, 410, or 310. The travel stops disclosed herein may be integrated in the case of a rocker arm whether rollers or slides are used, so that it is advantageous to control the movement of the inner arm relative to the body 110. Therefore, it is advantageous to include an evacuation stop, such as a pin 700, extending from the second (bearing) shaft 300. Depending on the diameter of the bearing shaft 300, and depending on the diameter of one of the post receivers 124, 125, 134, or 135, the evacuation stop may alternatively be an integrally formed extension of the bearing shaft 300. The integrally formed pin and the bearing shaft may be directly assembled.

[0102] The evacuation stop pin 700, 701, 703 may be inserted through one of the post receivers 124, 125, 134, 135, 1351 in the post 123, 133, as described in more detail below. Although only one outer arm 120 or 130 is required to be provided with a post receiver for inserting the evacuation stop, both arms 120 and 130 may be formed with receivers for selection during manufacturing or for light weight or structural balance. Although only one evacuation stop is shown in several of the figures, two may be used.

[0103] Go to Figure 4G , the inner sides 122, 132 of the outer arms 120, 130 are formed with grooves 126, 136 to serve as evacuation guides for the evacuation stops. For example, when the inner arms 200, 210 pivot within the outer arms 120, 130, the pin 700 can move through one of the grooves 126, 136. Limiting surfaces 1260, 1360 can be included in the inner sides 122, 132 so that the travel of the evacuation stops is limited. When the spring force from one of the springs 500, 506, 507, 509, 5060, 5070 lifts the latch arm 220 and biases the inner roller 310 toward the cam lobe 1003 and / or biases the latch arm 220 above the latch seat 901, the travel of the latch arm 220 can be limited by the evacuation stop against the limiting surface 1260. The grooves 126 , 136 may be unobstructed at the valve stem side of the body 110 to allow the inner arms 200 , 210 to have a larger pivot angle relative to the outer arms 120 , 130 .

[0104] Go to Figure 4G and Figure 5A , the inner arm assembly 2091 may include the inner arms 200, 210, the latch arm 220, the inner roller 310 and the pin 700. The inner roller 310 is shown as including multiple layers so that the portion of the inner roller 310 that contacts the cam lobe 1003 is a different material from the bearing shaft 300. However, a single stepped material may be used. However, it is worth noting that the bearing shaft diameter may be adjusted depending on the application. For example, the weight and inertia of the inner roller may be reduced by using a smaller diameter bearing shaft 300 installed in the inner arm 200, 210. Alternatively, lightweighting may be achieved by increasing the diameter of the hollow channel 313.

[0105] The pin 700 may be inserted into the evacuation stop receiver 314 prior to lowering the inner arm assembly 209 into the outer arm 120, 130. Alternatively, the pin 700 may be inserted through the post receiver 125 either before or after the pivot 302 couples the inner arm assembly 209 to the outer arm 120, 130. A positioning tool may be inserted through the post receiver 134 or 135 and through the hollow passage 313 to fix the depth of the pin 700 within the evacuation stop receiver 314 or to stabilize the position of the evacuation stop receiver as the pin 700 is inserted. A gap 128 may be maintained between the pin 700 and the fastener 413, or a gap 128 may be maintained between the pin 700 and the post receiver. Although Figure 4G Includes threaded post receivers 124, 134, but can be Figure 5A The optional pressed bushings 401, 411 of the embodiment of the present invention are used to avoid damaging such threads via the alignment tool. Then, the column receivers 125, 135 can be non-threaded or smooth.

[0106] Figure 5B An alternative travel stop is shown, such as by including two pins 700. The inner arm assembly 2092 may include the inner arms 200, 210, the latch arm 220, the inner roller 310, and the two pins 700. In addition, the inner roller 310 may include a rotatable bearing 3101 mounted on the second shaft 300. The needle roller 312 may be mounted between the second shaft 300 and the rotatable bearing to form a needle roller bearing assembly. Using two pins 700 may include a gap 128 and a mirror image gap 138. Although the pins 700 may be assembled before the inner arm assembly 209 is connected to the outer arm, one pin 700 may be inserted through the post receiver 125 into the evacuation stop receiver 313, and then the other pin 700 may be inserted through the post receiver 135 into the evacuation stop receiver 3131.

[0107] exist FIG. 5C to FIG. 5E Other alternatives are shown and described in . One strategy for providing clearance between the rocker arm inner roller 310 and the cam lobe 1003 of the 2-stage rocker arm is to control tolerances on the inner roller 310, for example, one or more of the inner diameter (ID) and outer diameter (OD) of the rotatable bearing 3101, the needle roller 312, and the bearing shaft 300. This stacking can add many tightly controlled tolerances, which makes the manufacturing process costly. Despite the benefits of travel stops, adding tolerances to the alignment of the pin 700 increases the stacking.

[0108] Go to Figure 5C, the inner arm assembly 2093 may include the inner arms 200, 210, the latch arm 220, the inner roller 310, and the partially tapered pin 701. To reduce costs, the tapered pin 701, the tapered hole for the post receiver 1351, and the evacuation stop receiver 314 or 3141 for seating the tapered pin 701 may be used. The stacking tolerance may then be controlled by the pressing depth of the pin 701. The pin 701 may include a cylindrical pin body 7010 for fitting in the cylindrical evacuation stop receiver 314 or 3141. The tapered portion 7013 of the pin may then be aligned relative to the tapered hole of the post receiver 1351.

[0109] Control of the gap between the cam on the cam track 1000 and the rocker rollers 400, 410, 310 (inner roller 310 in the case shown) may include a cost-effective way to control stacking during manufacturing. Additional means for using an adjustable device using a taper on a pin or hole are discussed below.

[0110] Instead of inner rollers on bearing shafts, alternative rocker arms may include slider pads. The slider pads may span a pair of inner arms. Alternatively, a single inner arm may be used. The shaft or other bridging portion between the outer arms may include at least one control pin mount, such as receivers 3131, 314, 3141, or 135.

[0111] exist Figure 5D In the embodiment of the present invention, the inner arm assembly 2094 may include the inner arms 200, 210, the latch arm 220, the inner roller 310 and the cylinder pin 700. The pin 700 is cylindrical along its body, as is the receiver 3131. However, the cone angle of the column receiver 1352 is relatively Figure 5C is the opposite. Therefore, Figure 5C In FIG. 1 , the taper angle increases from the inner side 132 to the outer side 131. However, in Figure 5D , the taper angle decreases from the inner side 132 to the outer side 131. A gap 138 can be maintained between the end of the pin 700 and the through portion of the post receiver 1352, but the position of the pin 700 against the overhanging portion of the tapered post receiver 1352 will control the position of the travel stop and therefore the gap adjustment. Figure 5D It is also shown that the inner side 122 can be parallel adjacent to the outer surface 260 .

[0112] like Figure 5EAs shown, the inner arm assembly 2095 may include the inner arms 200, 210, the latch arm 220, and the inner roller 310 including the control pin stop 3010. The inner roller design may include a bearing shaft 300 including the control pin stop 3010 or a cantilevered piece extending from the bearing shaft into the evacuation guide 136. A tapered edge 3133 may be included on the control pin stop 3010. One of the outer arms 130 may include a mount for the pin 703, such as a post receiver 135. The pin 703 may include a cylindrical body 7030 and a tapered portion 7033. While the tapered portion 7033 of the pin 701 increases the circumference of the pin as the taper extends from the cylindrical pin body 7030, the pin 703 decreases the circumference of the pin as the taper extends from the cylindrical pin body 7030. The inner arm assembly 209 includes the tapered edge 3133 as a control pin stop. Positioning the pin 703 in the post receiver 135 or other mount relative to the control pin stop sets the relative movement of the inner arm assembly 209 relative to the outer arms 120 , 130 .

[0113] According to the present disclosure, adjustable stop pins 700, 701, 703 can be designed instead of using only tolerances to control clearance. When tapering, the pins 701, 703 can taper at the same angle as the tapered hole on which the travel stop (control pin stop) is provided. To adjust the clearance, the pin can be pressed into the pin hole to a given depth: Figure 5C In the example of , a deeper depth is used to increase the clearance or a shallower depth is used to reduce the clearance. The depth will depend on the desired amount of clearance between the inner roller 310 and the inner cam lobe 1003. A gauge or other alignment tool can be used to hold the rocker arm in a position to align the inner roller 400 and the outer roller 410 to the desired clearance for the operating state. Then, when the stop pins 701, 703 are inserted and set (or pressed into their holes), they are pressed to a depth that aligns the parts with the gauge or other alignment tool.

[0114] Consistent with these examples, the rocker arm may include a first outer arm 120 and a second outer arm 130 connected by a pivot body 111. One of the first outer arm or the second outer arm includes an inner side 122, 132, and the inner side includes a limit surface 1260, 1360, 1352, 1354. The second (bearing) shaft 300 may be located between the first inner arm and the second inner arm. The pin 700, 701 may extend from the second shaft 300 toward one of the first outer arm or the second outer arm. The pin may be configured to reciprocate toward and away from the limit surface when the first inner arm and the second inner arm pivot between the first outer arm and the second outer arm.

[0115] The inner side may further include grooves 126, 136 having limiting surfaces 1260, 1360, 1352, 1354, and the pins 700, 701 may be configured to pivot toward and away from the limiting surfaces within the grooves when the first inner arm and the second inner arm pivot between the first outer arm and the second outer arm (for example, when the inner arm assembly 209 travels in a freewheeling manner).

[0116] The rocker arm may include a pair of outer arms 120, 130 including at least one control pin port, such as port receivers 124, 134, 125, 135, 1351, 1352 passing through at least one of the outer arms of the pair of outer arms. The inner arm assembly 209 may pivot relative to the outer arm. The inner arm assembly may include at least one pin mount, such as receivers 3131, 314, 3141, which may be part of the shaft 300 or other part of the inner arm assembly 209. The control pin 701, 703 may include a tapered portion 7033, 7013 and a body portion 7030, 7013, the control pin body being inserted into the control pin mount, and at least a portion of the tapered portion selectively contacting at least a portion of the control pin port.

[0117] The evacuation stop disclosed herein can be used with less complex rocker arms such as those disclosed in the figures. For example, the evacuation stop can be used in a rocker arm lacking cantilever rollers 400, 410. Thus, the rocker arm can include a pair of outer arms including at least one limiting surface 260, 360, 1353, 1354 on at least one of the outer arms of the pair of outer arms. The inner arm assembly can pivot relative to the outer arm. Control pins 700, 701 can be mounted to the inner arm to limit the travel of the inner arm assembly relative to the outer arm.

[0118] Alternatively, the rocker arm may include a pair of outer arms including at least one control pin mount, such as a port receiver 135 on at least one of the outer arms of the pair of outer arms. The inner arm assembly may pivot relative to the outer arm. The inner arm may include a restraining surface, such as a tapered edge 3133. A control pin, such as pin 703 including a tapered portion and a body portion, may be inserted into the control pin mount. At least a portion of the tapered portion 7033 may selectively contact at least a portion of the restraining surface.

[0119] Roller retention of three-roller rocker arm

[0120] Using rollers, such as roller bearings, needle bearings, or wheels, on the rocker arms can reduce friction losses when the actuator pushes against the rocker arms. Consider a Type II valve train including an overhead cam track 1000. The eccentrically shaped cam lobes are mounted to rotate with the cam track 1000, and the shapes of the lobes 1001, 1002, 1003 and the rotation speed of the cam track 1000 control the opening and closing of the engine valves. If a fixed surface (such as a slider pad) is used, the cam lobes scrape along the slider pad, which causes energy loss in the system. Using rollers on the rocker arms, rather than fixed surfaces such as slider pads, can reduce friction losses. Therefore, it is advantageous to use rollers 310 for the lost motion pivoting of the inner arms 200, 210, and it is also advantageous to use first and second outer rollers 400, 410 on the first and second outer arms 120, 130. As described above, the rollers 310 can include needle bearings. Similar and additional modifications of the outer rollers 400, 410 will be described in detail below.

[0121] By cantilever mounting the outer rollers 400, 410 on the columns 123, 133 on the outer sides 121, 131 of the outer arms 120, 130, the assembly and manufacturing benefits are significant.

[0122] The rocker arm may include a first outer arm 120 including a first inner side 122 and a first outer side 121, the first outer side including a first cantilever column 123. The first roller 400 may be mounted to the first cantilever column 123. The second outer arm 130 includes a second inner side 132 and a second outer side 131, the second inner side 132 facing the first inner side 122. The second outer side 131 includes a second cantilever column 133. The second roller 410 is mounted to the second cantilever column 133.

[0123] The first cantilevered post 123 may be integrally formed with the first outer side 121 by molding, machining, printing, etc. Similarly, the second cantilevered post 133 may be integrally formed with the second outer side 131. The first roller 400 may be cantilevered mounted on the mounting post 123 in line with the second shaft 300, which may be in line with the second roller 410.

[0124] The first and second cantilevered posts 123, 133 may include first and second post receivers 124, 134 or 125, 135 configured to receive the pin 700 and / or the fasteners 403, 413. The fasteners may be rivets or the like. Alternatively, the first and second post receivers 124, 134 may be threaded to receive the threaded fasteners 402, 413. The first roller 400 may include a central hole 4001, and the first roller may be mounted to the first cantilevered post by inserting a fastener such as a screw or rivet 403, 413 or a bushing 401, 411 through the central hole 4001 and by securing the fastener to the first cantilevered post 123. The outer roller may be held by extensions 4040, 4041 on washers, which are held in place by screwing in the fasteners. A similar approach may be used for the second roller 410 including a central hole 4101.

[0125] The first roller 400 may be mounted to the first cantilever column 123 by inserting the fastener 403 through the central hole 4001 and into the first column receiver 124 or 134. A washer 404, 414 or bushing may be inserted between the respective first roller 400 or second roller 410 and the fastener 403, 413 to facilitate rotation of the outer roller 400, 410, as shown in FIG. Figure 4G shown.

[0126] Alternatively, if Figure 5A As shown, the first and second cantilevered posts 123, 133 may include an outer surface, and fasteners 401, 411 may be mounted to the outer surface. Fasteners 401, 411 may be T-shaped bushings, and the T-shaped bushings may be press-fitted to the outer surface. The T-shaped bushings may be used to facilitate rotation of the outer roller and retain the outer roller. By using a "T" shaped cross-section, extensions 4010, 4111 on the T-shaped bushings provide lateral travel limitations for the outer rollers 400, 410, which prevents torsional forces from being transmitted to the cam lobes 1001, 1002. Similar extensions 4040, 4141 may be provided on washers 404, 414.

[0127] like Figure 5B As shown, the rocker arm may also include needle rollers 402, 412 between the outer rollers 400, 410. The outer rollers 400, 410 may constitute the outer race of the bearing assembly, and the bushings 401, 411 may constitute the inner race of the bearing assembly. The center holes 4001, 4101 may have a larger diameter to accommodate the needle rollers 402, 412. The extensions 4010, 4111 may limit the movement of the needle rollers 402, 412 and the outer rollers 400, 410 on the cantilever posts 123, 133.

[0128] Other implementations will be apparent to those skilled in the art from consideration of the specification and practice of the examples disclosed herein.

Claims

1. A rocker arm for a valve mechanism, comprising: a body comprising a pivot end, a valve end, a first outer side, and a second outer side; a first post connected to the first outer side and extending away from the first outer side; a second post connected to the second outer side and extending away from the second outer side opposite the first post; a latch mechanism positioned within the pivot end of the body, the latch mechanism including a latch finger configured to selectively move between a latched position in which the latch finger extends toward the valve end and an unlatched position in which the latch finger is retracted away from the valve end, the latch including a latch surface; an inner arm assembly pivotable from the valve end between the first outer side and the second outer side, the inner arm assembly including a latch arm pivotable from a position above the latch surface to a position below the latch finger; a first roller connected for rotation on the first post; a second roller connected for rotation on the second post; as well as At least one biasing mechanism biases the latch arm toward the position above the latch surface.

2. A valve mechanism, comprising: A rocker arm for a valve mechanism, the rocker arm comprising: a body comprising a pivot end, a valve end, a first outer side, and a second outer side; a first post connected to the first outer side and extending away from the first outer side; a second post connected to the second outer side and extending away from the second outer side opposite the first post; a latch mechanism positioned within the pivot end of the body, the latch mechanism including a latch finger configured to selectively move between a latched position in which the latch finger extends toward the valve end and an unlatched position in which the latch finger is retracted away from the valve end, the latch including a latch surface; an inner arm assembly pivotable from the valve end between the first outer side and the second outer side, the inner arm assembly including a latch arm pivotable from a position above the latch surface to a position below the latch finger, the inner arm assembly further including a bearing shaft and an inner roller rotatable on the bearing shaft; a first roller connected for rotation on the first post; a second roller connected for rotation on the second post; and at least one biasing mechanism that biases the latch arm toward the position above the latch surface; and A set of three rotating cam lobes are respectively configured to press against each of the first roller, the second roller, and the inner roller, wherein the at least one biasing mechanism biases the inner roller toward the set of rotating cam lobes.

3. A valve mechanism, comprising: A rocker arm for a valve mechanism, the rocker arm comprising: a body comprising a pivot end, a valve end, a first outer side, and a second outer side; a first post connected to the first outer side and extending away from the first outer side; a second post connected to the second outer side and extending away from the second outer side opposite the first post; a latch mechanism positioned within the pivot end of the body, the latch mechanism including a latch finger configured to selectively move between a latched position in which the latch finger extends toward the valve end and an unlatched position in which the latch finger is retracted away from the valve end, the latch including a latch surface; an inner arm assembly pivotable from the valve end between the first outer side and the second outer side, the inner arm assembly including a latch arm pivotable from a position above the latch surface to a position below the latch finger, the inner arm assembly further including a bearing shaft and an inner roller rotatable on the bearing shaft; a first roller connected for rotation on the first post; a second roller connected for rotation on the second post; and at least one biasing mechanism that biases the latch arm toward the position above the latch surface; and and a first, second and third rotating cam lobes, wherein the first, second and third rotating cam lobes are respectively configured to press on each of the first roller, the second roller and the inner roller, wherein the third rotating cam lobe is configured to selectively push the latch arm to rotate past the latch finger when the latch finger is in the unlatched position.

4. The valve mechanism of claim 3, wherein the latch arm is configured to latch against the latch surface when the latch finger is in the latched position and the latch arm is configured to rotate past the latch finger when the latch finger is in the unlatched position.

5. A rocker arm, comprising: a first outer arm, the first outer arm comprising a first inner side and a first outer side, the first outer side comprising a first cantilever column; a first outer roller mounted to the first cantilever column; a second outer arm, the second outer arm comprising a second inner side and a second outer side, the second inner side facing the first inner side, the second outer side comprising a second cantilever column; a second outer roller mounted to the second cantilever column; a pivot body connecting the first inner side to the second inner side; an actuatable latch mechanism, the latch mechanism being located within the pivoting body; an inner arm assembly including a latch arm pivotable adjacent the pivot body; as well as A pivot connects the inner arm assembly to pivot between the first outer arm and the second outer arm.

6. A type II valve mechanism, comprising: A rocker arm, comprising: a first outer arm, the first outer arm comprising a first inner side and a first outer side, the first outer side comprising a first cantilever column; a first outer roller mounted to the first cantilever column; a second outer arm, the second outer arm comprising a second inner side and a second outer side, the second inner side facing the first inner side, the second outer side comprising a second cantilever column; a second outer roller mounted to the second cantilever column; a pivot body connecting the first inner side to the second inner side; an actuatable latch mechanism, the latch mechanism being located within the pivoting body; an inner arm assembly including a latch arm pivotable adjacent the pivot body; and a pivot connecting the inner arm assembly to pivot between the first outer arm and the second outer arm; and first, second and third rotating cam lobes, wherein the first cam lobe is configured to press against the first outer arm, wherein the second cam lobe is configured to press against the second outer arm, and wherein the third cam lobe is configured to selectively urge the latch arm to rotate past the actuatable latch mechanism when the actuatable latch mechanism is in an unlatched position.

7. The type II valve train of claim 6, wherein the inner arm assembly is biased toward the third cam lobe by a spring force.

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