Roller rocker assembly

Abstract

The center pivot roller rocker arm assembly can include a primary roller rocker arm, a secondary roller rocker arm, and a latch assembly. The primary roller rocker arm can include a rocker shaft bore, a valve end, a cam end, and a primary cam surface on the cam end. The secondary roller rocker arm can include a secondary rocker shaft bore, a secondary cam end, and a secondary cam surface on the secondary cam end. The latch assembly can be coupled to the rocker shaft bore and configured to latch the primary roller rocker arm to the secondary roller rocker arm and unlatch the primary roller rocker arm from the secondary roller rocker arm. The lost motion assembly can be configured with the primary roller rocker arm and the secondary roller rocker arm. The primary cam surface and the secondary cam surface can have different ranges for receiving cam actuation.

Description

Technical Field

[0001] This application provides a roller rocker arm assembly. The main roller rocker arm can be latched and unlocked with a second roller rocker arm to change the lift profile to the valve end of the roller rocker arm assembly. Background Technology

[0002] The automotive industry is attempting to reduce fleet emissions to meet stringent regulations. Implementing systems such as Variable Valve Actuation (VVA), Variable Valve Timing (VVT), and Variable Valve Lift (VVL) can help address these challenges. However, these systems can be complex, custom-designed for specific valve mechanisms, and may require multiple cams for actuation. Custom design and scrapping of high-precision components present difficulties in practical implementation. Summary of the Invention

[0003] The methods and apparatus disclosed herein overcome the aforementioned drawbacks and improve upon the prior art through a roller rocker arm assembly, an overhead cam motor system including the roller rocker arm assembly, a latching assembly for the roller rocker arm assembly, and a primary cam surface and a secondary cam surface for the bias range of the roller rocker arm assembly.

[0004] The roller rocker arm assembly may include a main roller rocker arm (RRA), a second roller rocker arm (RRA), a latching assembly, and an idler assembly. The roller rocker arm assembly may be of the central pivot type, also known as Type III.

[0005] The central pivot roller rocker arm assembly may include a main roller rocker arm, a second roller rocker arm, and a latching assembly. The main roller rocker arm may include a rocker arm shaft bore, a valve end, a cam end, and a main cam surface on the cam end. The second roller rocker arm may include a second rocker arm shaft bore, a second cam end, and a second cam surface on the second cam end. The latching assembly may be coupled to the rocker arm shaft bore and is configured to latch the main roller rocker arm to the second roller rocker arm and to release the main roller rocker arm from the second roller rocker arm.

[0006] Other objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description or may become apparent by practice of the disclosure. These objects and advantages will also be achieved and attained by means of the elements and combinations particularly pointed out in the appended claims. Attached Figure Description

[0007] Figure 1 This is a view of the central pivot roller rocker arm assembly.

[0008] Figure 2 This is a view of a portion of the valve mechanism for an overhead camshaft engine system that includes a central pivot roller rocker arm assembly.

[0009] Figure 3 This is a cross-sectional view of the unlocked roller rocker arm assembly.

[0010] Figure 4A and Figure 4B This is a view of the latched roller rocker arm assembly.

[0011] Figure 5 This is an example of a switchable valve lift mode. Detailed Implementation

[0012] The examples shown in the accompanying drawings will now be referred to in detail. Throughout all the drawings, the same reference numerals will be used to denote the same or similar parts whenever possible.

[0013] The roller rocker arm 10 can be used in various situations where variable valve timing is required. Advantages include additional functionality, flexibility in changing valve lift angles, flexible use of latches, absence of overhead constant contact devices (elastic guides), and the ability to use a single actuating cam profile.

[0014] Other latching assemblies are also compatible. Although the radial latching assembly 300 is shown in latching region 202 herein, it can be replaced by a lateral assembly. The locking can be located between adjacent body portions 101, 201 in a direction parallel to the rocker arm axis 5.

[0015] In the automotive industry's efforts to reduce fleet emissions to meet stringent regulations, systems with auxiliary lift profiles (also known as variable valve actuation (VVA), variable valve timing (VVT), variable valve lift (VVL), etc.) can be designed. Although Figure 5 The working example supports switching between intake valve delayed closing (LIVC) mode and drive mode, but the idea can be used in various VVA systems where the lift profile is different for each engine cycle. Advance or delayed actuation can be applied to intake or exhaust valves to support known technologies such as exhaust valve advance opening (LEVO), intake valve advance closing (EIVC), exhaust valve delayed opening (LEVO), exhaust valve delayed closing (LEVC), negative valve overlap (NVO), internal exhaust gas recirculation (iEGR), and many others. Therefore, the teachings herein can be applied to intake valves, exhaust valves, or combinations of intake and exhaust valves. Additional flexibility for auxiliary or drive mode actuation can be obtained via a bladder 113 in valve end 103. Clearance adjusters, lubrication sleeves, deactivation bladders, brake bladders, or other structures can be mounted in the valve end. Foot 123 is also shown.

[0016] exist Figures 1-4BThe diagram shows a roller rocker arm assembly 10 for use in an overhead camshaft (OHC) III engine system. When assembled with valves 2 and 3, reference can be made to valve mechanism 1. Due to the compatibility of roller rocker arm assembly 10 with the OHC III engine system, this roller rocker arm assembly may be referred to as a center pivot roller rocker arm assembly. A main roller rocker arm (RRA) 100, a second roller rocker arm (RRA) 200, a latching assembly 300, and an actuation assembly 400 are shown.

[0017] The valve mechanism 1 may include a rotatable cam 6, which may include a single convex angle profile or a set of convex angle profiles. For ease of manufacture, it may have a single convex angle profile, but a main convex angle having a main lift profile 61 and a main base circle 63 may be paired with a second convex angle having a second lift profile 62 and a second base circle 64. A rocker arm shaft 5 having an oil port 51 and an outlet 52 may be configured parallel to the cam track for the cam 6. A roller rocker arm assembly 10 may rotate on the rocker arm shaft 5 in response to rotating the cam 6. Valves 2 and 3 may be raised and lowered. A valve bridge 4 may be included, allowing more than one valve 2 or 3 to be actuated at a time. However, actuation of a single valve is not excluded.

[0018] The design of the cam cam angle 6 controls the degree of movement of valves 2 and 3. However, additional design freedom can be achieved by designing the main cam surface 126 and the second cam surface 226. For example... Figure 5 As shown by the dashed lines, the drive mode can be configured to raise and lower the valves, with the shape of cam 6 indicating the lift profile. The Intake Valve Delayed Closing (LIVC) mode can follow many drive mode lift profiles before switching to a new profile that extends beyond the drive mode lift profile, causing valves 2 and 3 to close later in LIVC mode than in drive mode. Switching between drive mode and LIVC mode is achieved by actuating the latch assembly 300.

[0019] The main cam surface 126 can be configured to receive the drive mode lift profile from the cam 6 when the latch assembly 300 is released from latch. Figure 3 However, when the latch assembly 300 is latched, the roller rocker arm assembly 10 can be switched from the main cam surface 126 following cam 6 to the second cam surface 226 following cam 6. This is a sudden step to a new lift profile. Figure 5 Unlike existing rocker arms (the cross section), the disclosed roller rocker arm assembly 10 maintains a smooth valve lift profile without "stepping out" or causing contact stress or impact on the components to achieve a change in the valve lift profile. It smoothly transitions to the auxiliary valve lift profile (LIVC mode in this example) without harsh contact stress.

[0020] This is achieved by having a point where both the main cam surface 126 and the second cam surface 226 are in contact with the cam 6 simultaneously. At that point, the valve speed can be approximately zero.

[0021] Therefore, when the latch assembly 300 is latched, the cam 6 can rotate from the main base circle 63 to the main lift profile 61, as... Figure 4A As shown. Figure 4A Corresponding to Figure 5 The cam angle is approximately 230-240 degrees. As cam 6 rotates further, the second cam surface 226 contacts cam 6, as... Figure 4B As shown. The second lift profile 62 can be an extension of the main lift profile 61, such as by being an integral part. Alternatively, an additional profile can be provided to the second lift profile 62 to maintain valve open or regulate valves 2 and 3 closed. Figure 4B As shown, both the main cam surface 126 and the second cam surface 226 contact the cam 6. This corresponds to... Figure 5 The cam angle is approximately 250 degrees. The second cam surface 226 follows the cam 6 through the remaining cam rotation, and auxiliary (LIVC mode) valve lift is applied to valves 2 and 3.

[0022] When the latch assembly 300 is released, the second cam surface 226 cannot transmit any of its lift profile to the roller rocker arm assembly 10. Even if the second cam surface 226 contacts the cam 6, no force is transmitted to the valve end 103. However, during the drive mode, the main cam surface 126 of the main roller rocker arm 100 remains in direct contact with the cam 6. However, at the top of the valve lift, the second cam surface 226 of the second roller rocker arm 200 begins to roll on the cam 6. The agitator assembly 400 pushes on the second roller rocker arm 200 such that the agitator spring 404 causes the second cam surface 226 to contact the cam 6. The second roller rocker arm 200 is then able to oscillate in an agitated manner.

[0023] Following a command from the electronic control unit (ECU) to the oil control valve (OCV), hydraulic fluid, such as oil, can flow through an oil groove formed by port 51 to outlet 52. Pressure can actuate latch assembly 300. Latch assembly 300 may include a main latch socket 130 in the main roller rocker arm 100. The main latch socket 130 may extend from a rocker arm shaft bore 150 in the body portion 101. The main latch 301 may be configured to slide in the main latch socket 130 in response to pressurized hydraulic fluid, such that the main latch 301 slides to engage the second roller rocker arm 200. The main latch 301 may slide into a second latch socket 230 in the second roller rocker arm 200 to latch the main roller rocker arm 100 to the second roller rocker arm 200. This may press the auxiliary latch 302 to slide toward the bias wall 231 in the second latch socket 230. The pressure plate 321 with plate guide 322 can restrict the travel of the main latch 301 into the second latch socket 230, such as by the plate guide 322 abutting the bias wall 231 or other stop. In this way, the main latch 301 does not travel excessively or leave the main latch socket 130.

[0024] As the pressurized hydraulic fluid decreases against the oil wall 311 of the main latch 301, the latching end 312 of the main latch 301 is pushed back into the main latch socket 130 and out of the second latch socket 230 by the latch spring 320 against the bias wall 231 and the pressure plate 321. Although a stop may be included to limit the travel of the main latch 301, the rocker arm shaft 5 may alternatively act as a travel limiter. For enclosure, the main latch socket 130 may be offset in the body portion 201 such that the latch socket 130 is not coplanar with the main cam surface 126. The cam end 206 may include a roller pin 216 in a pin hole 236, on which a roller rotates as the main cam surface 226. These elements may be enclosed parallel to the main latch socket 130 in the main body portion 101. The second latch socket 230 may then be constructed between the second cam surface 226 and the idler mount 204. These can be packaged parallel to the surface of the main cam. This geometry allows for a tighter package. The latch can be accommodated without extending the main cam surface 126 further away from the pivot point at the rocker arm shaft 5.

[0025] In other words, the main roller rocker arm 100 may include a recess 160 in the cam end 106. The second cam end 206 may be seated in the recess 160. The recess 160 may be formed in the main roller rocker arm 100 by means of a step, such that the cam end 106 and the valve end 103 are coplanar, but the idler mount 104 is not coplanar with the cam end 106 or the valve end 103. The second roller rocker arm 200 may also be stepped to swing in the recess 160, such that the body portion 201 abuts the main roller rocker arm 100, while the second idler mount 204 is coplanar with the idler mount 104 and the second cam surface 226.

[0026] The pneumatic assembly 400 can be connected between the main roller rocker arm 100 and the second roller rocker arm 200. The pneumatic assembly 400 can be positioned above the rocker arm shaft hole 150. Due to its stepped geometry, the pneumatic assembly 400 can also be positioned above the second cam end 206.

[0027] The pneumatic assembly 400 may include a pneumatic recess 104 on the main roller rocker arm 100 and a pneumatic mount 204 at or above the second cam end 206. A spring guide 401 may include a pivot end 411 mounted to the pneumatic mount 204. The second pneumatic mount 204 may include a U-shaped clip with a pin hole 214 to anchor the shank of the pivot end 411. The main pneumatic mount 104 may include a recess 140, and the second pneumatic mount 104 may include a U-shaped clip. The spring guide 401 may be mounted across the recess 140 and the U-shaped clip. A guide end 421 of the spring guide 401 may be positioned in the pneumatic recess 104. A rotatable member 403 may be received to rotate within the recess 140 of the pneumatic mount 104. A ball-and-socket arrangement may be present, where a semi-cylinder is shown for the rotatable member 403. The guide end 421 may be positioned together with the rotatable member 403. The rotatable member 403 may include a channel 413. A guide end 421 is slidable within the channel 413. The idler socket 140 may include a socket channel 144. A guide end is slidable within the socket channel 144. Then, when the latch assembly 300 is released, a small amount of clearance (hereinafter referred to as "oscillation") can be given to the second roller rocker arm 200. Movement in the second roller rocker arm 200 can be guided by the rotatable member 403 seated in the socket 140, and the guide end 421 of the spring guide 401 is guided in one or both of the channel 413 and the socket channel 144.

[0028] The pneumatic spring 404 can press against the pivot end 411 and the rotatable member 403 to push the second roller rocker arm 200 relative to the main roller rocker arm 100, and the force guides the second cam surface 226 to roll on the cam 6 even when the latch assembly 300 is released.

[0029] The latching assembly 300 can combine the main roller rocker arm 100 and the second roller rocker arm 200. The main roller on the main cam surface 126 can contact the cam 6 until the second roller on the second cam surface 226 performs the valve lift function. This can be done at a point where the valve speed is approximately zero. By designing the rocker arm ratio difference between the main roller and the second roller, the valve closing point is different.

[0030] The main cam surface and the second cam surface can have different ranges for receiving cam actuation. This design feature increases additional design freedom. The main roller and the second roller can optionally mate with cam 6. Alternatively, roller pins 116, 226 can be manufactured for easy replacement of the main roller or the second roller, allowing different auxiliary functions and drive modes of valve lift profiles to be mounted on stock sets of the main roller rocker arm 100 and the second roller rocker arm 200. For example, the lift height can be varied by the diameter of the main roller or the second roller (and other options) while keeping the same cam 6. Different diameters or different mounting angles provide different lift profiles for the main cam surface and the second cam surface. If this rolling or selective mating is not desired, tappets or other sliding surfaces can be used instead of the main roller and the second roller.

[0031] The roller rocker arm assembly 10 is designed such that, at maximum valve lift (≈zero valve speed), there is a point where the main roller and the second roller on the main cam surface 126 and the second cam surface 226 simultaneously contact each other. However, when the latch assembly 300 is released, the main cam surface 126 is configured to transmit the main valve lift profile to the valve end 103. When the latch assembly 300 is latched, the second cam surface 226 is configured to transmit the second valve lift profile to the valve end 103.

[0032] The roller rocker arm assembly 10 can be configured such that the main cam surface 126 is configured with a main range of rollers, and the second cam surface 226 is configured with a second range of second rollers. The main range and the second range can be configured such that when the latching assembly is released, the rotating cam 6 does not act on either the main cam surface 126 or the second cam surface 226. Then, only the main cam surface 126 transmits the action of the cam 6 to the valve end 103.

[0033] The main cam surface 126 may be configured with a main range of rollers, and the second cam surface 226 may be configured with a second range of second rollers. The main and second ranges may be configured such that when the latching assembly is latched, the rotary cam 6 acts on both the main cam surface 126 and the second cam surface 226. This dual action can be limited to a small number of cam rotation degrees.

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

Claims

1. A center pivot roller rocker assembly comprising a primary roller rocker, the primary roller rocker comprising: a rocker shaft bore; a valve end; a cam end; and a primary cam surface on the cam end; a secondary roller rocker, the secondary roller rocker comprising: a secondary rocker shaft bore; a secondary cam end; and a secondary cam surface on the secondary cam end; a latch assembly coupled to the rocker shaft bore and configured to latch the primary roller rocker to the secondary roller rocker and unlatch the primary roller rocker from the secondary roller rocker; and an idle assembly coupled between the primary roller rocker and the secondary roller rocker; wherein the idle assembly comprises: an idle socket on the primary roller rocker; an idle mount at the secondary cam end; and a spring guide, the spring guide comprising: a pivot end mounted to the idle mount; and a guide end positioned in the idle socket.

2. The center pivot roller rocker assembly of claim 1, wherein the idle assembly is positioned above the rocker shaft bore.

3. The center pivot roller rocker assembly of claim 1, wherein the idle assembly comprises a rotatable member, and wherein the guide end is positioned with the rotatable member.

4. The center pivot roller rocker assembly of claim 3, wherein the rotatable member comprises a channel, and wherein the guide end is slidable in the channel.

5. The center pivot roller rocker assembly of claim 4, wherein the idle socket comprises a socket channel, and wherein the guide end is slidable in the socket channel.

6. The center pivot roller rocker assembly of claim 1, wherein the primary cam surface is configured to impart a primary valve lift profile to the valve end when the latch assembly is unlatched, and the secondary cam surface is configured to impart a secondary valve lift profile to the valve end when the latch assembly is latched.

7. The center pivot roller rocker assembly of claim 1 or 6, wherein the primary cam surface is configured with a primary range of rollers, and wherein the secondary cam surface is configured with a secondary range of second rollers, and wherein the primary range and the secondary range are configured such that a rotating cam does not act on both the primary cam surface and the secondary cam surface when the latch assembly is unlatched.

8. The center pivot roller rocker assembly of claim 1 or 6, wherein the primary cam surface is configured with a primary range of rollers, and wherein the secondary cam surface is configured with a secondary range of second rollers, and wherein the primary range and the secondary range are configured such that a rotating cam acts on both the primary cam surface and the secondary cam surface when the latch assembly is latched.

9. The center pivot roller rocker assembly of claim 1, wherein the primary roller rocker comprises a primary latch receptacle extending from the rocker shaft bore and a primary latch configured to slide in the primary latch receptacle, and wherein the secondary roller rocker comprises a secondary latch receptacle and a secondary latch configured to slide in the secondary latch receptacle.

10. The center pivot roller rocker arm assembly of claim 9, wherein the second latch receptacle is structured between the second cam surface and the lost motion mount.

11. The center pivot roller rocker arm assembly of claim 1, wherein the main roller rocker arm includes a recess in the cam end, and wherein the second cam end sits in the recess.

12. The center pivot roller rocker arm assembly of claim 1, wherein the main roller rocker arm is stepped such that the cam end and the valve end are coplanar, but the lost motion mount is not coplanar with the cam end or the valve end, and wherein the second roller rocker arm is stepped such that the main body portion abuts the main roller rocker arm while the second lost motion mount is coplanar with the lost motion mount and the second cam surface.

13. The center pivot roller rocker arm assembly of claim 12, wherein the lost motion mount includes a socket, wherein the second lost motion mount includes a clevis, and wherein a spring guide is mounted across the socket and the clevis.

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