Switchable rocker arm

Abstract

To provide a switchable rocker arm which satisfies one or more targets such as light weight, an integrated assembly and high-density mounting.SOLUTION: A switchable rocker arm 1 can comprise a main body 10 which is constituted so as to rotate with a rocker shaft as a center. The main body can include a valve end part 102 and a cam end part including a piston hole 135. A second main body 21 can include a pivot part, a transmission part for receiving a cam, and a latch hole penetrating the transmission part. A latch assembly can be attached into the latch hole. A piston assembly can be attached into the piston hole.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The switchable rocker arm includes a latch assembly mounted through a transfer portion of the second body. The lost motion spring may be integral with the second body. Several pivot points are shown as options for pivoting the second body relative to the main body. [Background technology]

[0002] Switchable rocker arms enable variable valve actuation techniques such as cylinder deactivation in combustion machines, but there are still challenges associated with implementing the switching functionality within the tight spaces of the machines. Summary of the Invention

[0003] It has been found that switchable rocker arms enable variable valve actuation techniques such as cylinder deactivation and switched lift events such as early or late valve opening or closing, or higher or lower relative lift height valve opening and closing (e.g., EEVO, EEVC, LIVC, EIVO, NVO, iEGR, engine braking, etc.). A lightweight design is desirable to reduce the overall weight of the machine. It is desirable to manufacture integrally for ease of installation on the machine, either as original manufacture or a replacement part. However, there are still challenges with implementing the switching functionality within the tight spaces of the machine.

[0004] To solve one or more of the problems outlined above, several switchable rocker arms are shown. Such switchable rocker arms include a body configured to rotate about a rocker shaft. The body can include a valve end and a cam end including a piston bore. A second body can include a pivot portion, a transmission portion that receives the cam, and a latch bore that extends through the transmission portion. A latch assembly is mounted within the latch bore. A piston assembly is mounted within the piston bore.

[0005] In an additional aspect, the switchable rocker arm can include a cam end that diverges to form a first arm border portion including a first piston bore and a first end wall and a second arm border portion including a second piston bore and a second end wall. The piston assembly can include a first piston seated in the first piston bore and a second piston seated in the second piston bore. The switchable rocker arm can include a hydraulic supply on the body, the hydraulic supply configured to supply hydraulic fluid to the first piston bore and the second piston bore.

[0006] A lost motion spring may be mounted over the transmission. The lost motion spring may have a center of inertia balanced over the entire transmission. A spring plate may be fixed to the cam end to seat the lost motion spring.

[0007] The transmission may include a bearing axle and a roller bearing mounted for rotation on the bearing axle. The bearing axle may include a latch hole. The latch assembly may include a first latch and a second latch biased outwardly of the latch hole.

[0008] The transmission portion may include a concave body configured to form a frame for the bearing axle. The transmission portion may be further configured to seat the lost motion spring. The second body may be configured to anchor to the pivot portion. The pivot portion may include a pair of rocker shaft bearings configured to rotate about the rocker shaft. The second arm may include a stamped seat forming the concave body, the pivot portion, and the connecting body. The connecting body may span a portion of the body between the rocker shaft bore and the cam end.

[0009] The switchable rocker arm may include a spring frame, the spring frame including a first prong abutting the transmission part, a second prong abutting the transmission part, and a spring seat spanning between the first prong and the second prong. The spring frame may cover the transmission part from a first side, and the second body may include a concave frame covering the transmission part from the first side. Or, the spring frame may cover the transmission part from the first side, and the second body may include a concave frame covering the transmission part from the second side.

[0010] Additional objectives 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 present disclosure. The objectives and advantages will also be realized and obtained by means of the elements and combinations particularly pointed out in the appended claims. [Brief description of the drawings]

[0011] [Figure 1] FIG. [Diagram 2] FIG. 2 is a cross-sectional view of a portion of the rocker arm of FIG. 1 showing the latch assembly and piston assembly in a transmission region. [Diagram 3] FIG. [Figure 4A] FIG. 13 is a comparative view of a second body disposed on the main body. [Figure 4B] FIG. 4B is a comparative view of a second body placed on the main body, showing the lost motion position. [Figure 4AA] 1 shows the latch assembly unlatched by the piston assembly and the second body ready to move relative to the main body. [Figure 4BB] The second body is shown moved in the lost motion direction (indicated by the arrow). A combination of travel stops and travel limiters limits the movement of the second body. This combination is one option that allows for other variable valve lift technologies. [Figure 5A] 1 shows an alternative second body. [Figure 5B] 1 shows an alternative second body. [Figure 6A] 1 shows an alternative second body. [Figure 6B] 1 shows an alternative second body. [Figure 6C] 1 shows an alternative second body. [Figure 7A] 1 shows an alternative spring plate, a body, and a second body. [Figure 7B] 1 shows an alternative spring plate, a body, and a second body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Reference will now be made in detail to the examples illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0013] To meet one or more goals of light weight, integral assembly, and high density packaging, several switchable rocker arms are illustrated. Such switchable rocker arms 1-4 may include a body 10, 11 configured to rotate about a rocker shaft. The body 10, 11 may include a valve end 102 and a cam end 130. The valve end 102 may include a knuckle for acting on a valve stem or valve bridge, or the valve end 102 may include a socket 111 for a capsule or spigot for functions such as lash adjustment, engine braking, etc. As illustrated, the socket 111 includes a lash pin 112, a lash nut 113, and an e-foot (elephant foot) 114. The cam end 103 may include at least one piston hole 135, 136. Preferably, the cam end 103 is bifurcated to provide two piston holes 135, 136. And, the second body 21-24 may be seated for selective pivot movement between the branches of the cam end 103.

[0014] The second bodies 21-24 may include pivot portions 2140, 2240, 2340, 2440, transmission portions 2130, 2230, 2330, 2430 that receive cams, and latch holes 2132 that pass through the transmission portions. A latch assembly 60 is mounted in the latch hole 2132. A piston assembly 50 is mounted in at least one of the piston holes 135, 136.

[0015] The bodies 10, 11 can be lightweight by including hollow portions. A rocker shaft bore 101 can be included, which may or may not have bushings for orienting the rocker arms 1-4 on the rocker shaft. The rocker shaft can be supplied with hydraulic fluid to control the piston assembly 50. The hydraulic assembly 150 can be configured with a hydraulic port 151, a hydraulic supply 152, hydraulic outlets 153, 154, and an optional leak port 155.

[0016] The switchable rocker arms 1-4 may include a cam end 103 bifurcated to form a first arm border portion 131 including a first piston bore 135 and a first end wall 133, and a second arm border portion 132 including a second piston bore 136 and a second end wall 134. The first end wall 133 and the second end wall 134 may be formed to include a first piston bushing 53 and a second piston bushing 54 that are fitted into the first piston bore 135 and the second piston bore 136, as shown. Alternatively, one or both of the first piston bore 135 and the second piston bore 136 may be formed as blind bores such that the first and second end walls are integrally formed with the first arm border portion 131 and the second arm border portion 132. As a further option, the first arm border portion 131 and the second arm border portion 132 may be formed with fastener receptacles 161, 162 or optional alignment posts or other mechanisms for securing the spring plates 31 or 32.

[0017] The piston assembly 50 may include a first piston 51 seated in the first piston bore 135 and a second piston 52 seated in the second piston bore 136. The switchable rocker arms 1-4 may include a hydraulic supply 152 in the body 10, 11 configured to supply hydraulic fluid to the first piston bore 135 and the second piston bore 136. The hydraulic supply 152 may include hydraulic outlets 153, 154 in fluid communication with the first piston bore 135 and the second piston bore 136. As an option, leak ports 155 may be cross-drilled through the first piston bore 135 and the second piston bore 136. And the first and second piston bushings 53, 54 may further include oil cups 531, 541 for collecting pressurized fluid and cross-drilled oil supplies 532, 542 for receiving hydraulic control fluid for controlling the pistons 51, 52. The first and second piston bushings 53, 54 may include inner walls 534, 544 that act as travel limits for the piston ends 515, 516. Optionally, glands or other grooves or ports may be included in the first and second bushings 53, 54 and the pistons 51, 52 to facilitate distribution of hydraulic control fluid. The inner walls 534, 544 may optionally be part of the piston bores in blind bore variations.

[0018] The pistons 51, 52 may include a piston body 510, 520 having a piston facing 511, 521. An optional protrusion 512, 522 or nose may be included on the piston facing 511, 512. The protrusion 512, 522 may act as a travel stop cooperating with the travel limiters 2161, 2162. The piston body 510, 520 may include a pressure chamber 513, 523. The reduced diameter of the pistons 51, 52 allows for a reduced volume of hydraulic control fluid to be actuated with a fast response time.

[0019] Instead of an overhead reaction bar, a lost motion spring 40 may be mounted on the transmission 2130, 2230, 2330, 2430. The lost motion spring 40 may have a center of inertia balanced with respect to the entire transmission 2130, 2230, 2330, 2430. The spring plates 31, 32 may be secured to the cam end 103 to seat the lost motion spring 40. The first spring end 41 may be biased against a portion of the second body 21-24 and the second spring end 42 may be biased against the spring plates 31, 32. This biases the second body 21-24 towards a position where the latch assembly 60 can latch into the piston bore 135, 136.

[0020] The spring plates 31, 32 may include spring plate ends 311, 312 or 321, 322 configured to couple to the bifurcated body. For example, the first and second arm border portions 133, 134 may include fastener receptacles 161, 162 for receiving fasteners 61, 62, such as screws or rivets. Alternatively, welding may be used to secure the spring plates 31, 32. Alternatively, prongs, pins, screws, or the like may protrude from the first and second arm border portions 133, 134 to receive nuts or caps. The spring plates 31, 32 may include a lost motion seat 33 with an optional protrusion or groove for positioning the second spring end 42. Instead of a continuous sheet of material, a cage configuration may be provided with cage arms 323, 324. To provide a trajectory for the spring force of lost motion spring 40, spring plates 31 may be straight in a square configuration (FIGS. 1, 2, 4A-6A, 6C) or spring plates 32 may be angled in an angled configuration (FIGS. 7A, 7B).

[0021] The transmission 2130, 2230, 2330, 2430 may include a bearing axle 2131 and a roller bearing 2134 mounted for rotation on the bearing axle 2131. An optional needle bearing may be included between the roller bearing 2134 and the bearing axle 2131. A slider pad integrated with the bearing axle 2131 is an alternative. The bearing axle 2131 may include a latch hole 2132. The latch assembly 60 may include a first latch 61 and a second latch 62 biased outwardly of the latch hole 2132. If only one piston 51 or 52 is used, it is considered that only one latch 61 or 62 is needed. A blind hole, a snap ring, a bushing, or other stay may be used to bias one latch 61 or 62 toward one piston 51 or 52. However, as shown, the latch spring 615 can push the latch ends 613, 623 apart to form the latch cavity 616. The latch spring 615 can seat in spring cups 614, 624 in the latch bodies 611, 621. The latch facings 612, 622 can face the pistons 51, 52 to compress the latch spring 615 using hydraulic control fluid to push the pistons 51, 52 into the piston bores 135, 136 until the latch ends 612, 623 are abutted. Other travel limiters such as bushings, cast walls, snap rings, etc. may be used for the latches 61, 62. This configuration allows for a dry latch bore 2132 without the use of hydraulic control fluid. The second body 21-24 may be lubricated via a hydraulic supply in the piston bores 135, 136 or in the body 10, 11, or may not be lubricated at all. The rotating cams may be lubricated via the bodies 10, 11 but not via the second bodies 21-24, which makes the second bodies 21-24 lighter and simpler.

[0022] In the first configuration, the second body 21 can be coupled to the pivot mounts 141, 142 via the pivot axle 143. The pivot area 140 is formed by a part of the body 10 near the cam end 103 and connecting to the pivot part 2140 of the second body 21. The second body 21 can include pivot mounts 2141, 2142 for connecting to the pivot axle 143. The transmission part 2130 can include a concave body 211 configured to form a frame for the bearing axle 2131. The ends 2135, 2136 of the bearing axle 2131 can be fixed in the bearing slots 216, 217. The concave body can include connecting beams 212, 213 spanning above the transmission part 2130 and for seating the lost motion spring 40. From the connecting beams 212, 213, struts 214, 215 can extend to include the bearing slots 216, 217. Optional platform sockets 218, 219 may extend from the struts 214, 215 or the connecting beams 212, 213 to form a pivot point for the spring platform 2131. The spring platform 2131 may seat the lost motion spring 40 by means of an optional spring guide 2132 (which may alternatively be a groove or other guide). The platform guides 2133, 2134 may extend into the platform sockets 218, 219 to pivot the spring platform 2131. The plate portion 2135 may pivot or rock when the lost motion spring 40 contracts (FIG. 4BB) or extends back towards the latched position (FIG. 2). Thus, the transmission portion 2130 may be configured to seat the lost motion spring 40. The second body 21 may be configured to be tethered to the pivot portion 140. The second arm 21 may include a stamped sheet forming the concave body 211, the second pivot portion 2140 and the connecting beams 212,213.

[0023] Figure 2 shows the latched position of the latch assembly 60. Figure 4AA shows the unlatched position and Figures 4B and 4BB show the lost motion positions. Figure 4A shows the positions where the latch assembly 60 is movable between the latched and unlatched positions. These latched positions can be used with the second body 22-24 of Figures 5A-7B, where Figure 7B shows a further lost motion position with a cross section of a hollow roller bearing 2134.

[0024] In Fig. 5A and 5B, the transmission part 2230 can include a concave body 221 configured to form a frame of the bearing axle 2131. This concave body 221 is configured with connecting beams 222, 223 that form a frame of the roller bearing 2134 from the lower side (second side relative to the spring platform 2131). The struts 224, 225 include bearing slots 226. This can further facilitate a drop-in assembly method of the bearing axle 2131. A connecting body 228 extends from the concave body 221. From the connecting body 228 extend side arms 2282, 2283, which can include pivot mounts 2241, 2242 in the form of rocker shaft bearings. The pivot mounts 2241, 2242 of the pivot part 2240 are located in the same position as the rocker shaft hole 101 so that the rocker shaft can serve as a pivot position for both the main body 11 and the second body 22. The second body 22 can be formed from stamped sheet material and is therefore very lightweight. Low cost can be achieved. The transmission part 2230 can be further configured to seat the lost motion spring 40. The spring platform 2231 can include a plate part 2237 having an optional spring guide 2232. From the plate part 2237, platform struts 2233, 2234 having platform bearing slots 2235 can extend. The spring platform 2231 can rest on the bearing axle 2131. The platform bearing slots 2235 can be designed to hold the bearing axle 2131. Thus, the second body 22 can be configured to be anchored to the pivot part 2240, here the rocker shaft. The pivot part 2240 can include a pair of rocker shaft bearings as pivot mounts 2241, 2242 configured to rotate about the rocker shaft. The second arm 22 may include a stamped sheet that forms the concave body 221 , the pivot portions (pivot mounts 2241 , 2242 ), and the connecting body 228 .The connecting body 228 may span a portion of the body 11 between the rocker shaft hole 101 and the cam end 103. A spring frame (spring platform 2231) may cover the transmission part 2230 from a first side, and the second body 22 may include a concave frame 221 that covers the transmission part 2230 from a second side.

[0025] 6A and 6B, the transmission part 2330 can include a concave body 231 configured to form a frame of the bearing axle 2131. This concave body 231 is configured with connecting beams 232, 233 that form a frame of the roller bearing 2134 from the upper side (first side relative to the spring platform 2231). Struts 234, 2324, 235, 2325 are attached to the beams 239, 2329 and form the bearing slots 236. This can further facilitate a drop-in assembly method of the bearing axle 2131. A connecting body 238 extends from the concave body 231. A bracket 2381 extends upwards over a portion of the body 11. Side arms 2382, 2383 extend from the bracket 2381 of the connecting body 238, and the side arms 2382, 2383 can include pivot mounts 2341, 2342 in the form of rocker shaft bearings. The pivot mounts 2341, 2342 of the pivot part 2340 are located at the same position as the rocker shaft hole 101 so that the rocker shaft can act as a pivot location for both the main body 11 and the second body 23. The second body 23 can be formed from stamped sheet material and is therefore very lightweight. Low cost can be achieved. The transmission part 2330 can be further configured to seat the lost motion spring 40. The spring platform 2231 can be configured as described above. The spring platform 2231 can rest on the bearing axle 2131. The platform bearing slot 2235 can be designed to catch the bearing axle 2131. Thus, the second body 23 can be configured to be anchored to the pivot part 2340, here the rocker shaft. The pivot part 2340 can include a pair of rocker shaft bearings as pivot mounts 2341, 2342 configured to rotate about the rocker shaft. The second arm 23 may include a stamped sheet that forms the concave body 231 , the pivot portions (pivot mounts 2341 , 2342 ), and the connecting body 238 .The connecting body 238 may span a portion of the body 11 between the rocker shaft hole 101 and the cam end 103. The spring frame (spring platform 2231) may include a first prong formed by a platform strut 2233 for abutting the transmission part 2230, a second prong formed by a strut 2234 for abutting the transmission part 2230, and a spring seat formed by a plate part 2237 spanned between the first prong and the second prong. The spring frame (spring platform 2231) may cover the transmission part 2230 from a first side, and the second body 23 may include a concave frame 231 covering the transmission part 2230 from the first side.

[0026] The main body 10 can be used with the second body 24. The pivot portion 140 can be near the rocker shaft hole 101 but does not overlap the rocker shaft hole 101. For material efficiency, the second body 24 can be angled away from the bottom of the rocker shaft hole 101. The spring plate 31 can then be fixed or tilted at an angle so that the spring plate 31 positions the lost motion spring 40 such that the lost motion spring 40 biases the latch hole 2132 to align the latches 51, 52 with the piston holes 135, 136. The lid 320 can form a spring guide 33, similar to the lid 310. To match the angle of the spring plate 32, the concave portion 241 of the second body 24 can include an angled spring platform 2431. The struts 224, 225 can also be angled. The transmission part 2430 may include a concave body 241 configured to form a frame for the bearing axle 2131. The transmission part 2430 may be configured to seat the lost motion spring 40. The second body 24 may be configured to be anchored to the pivot part 2440. The pivot part 2440 may include a pair of primary pivot mounts 141 connected to a pair of second pivot mounts 2441 via the pivot axle 143. The second arm 24 may include a stamped sheet forming the concave body 241, the pivot part (second pivot mount 2441).

[0027] Stamped sheet forming is used for the concave bodies 211, 221, 231, 241, although other techniques such as machining, cold forming, casting, etc. can be used to form these components. In the case of casting, the inserts and attachments can be used as bushings, bearings, or retainers.

[0028] 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 switchable rocker arm, comprising: a body configured to rotate about a rocker shaft and including a valve end and a cam end; a second body including a cam-receiving transmission portion and a latch hole extending through the cam-receiving transmission portion, the cam-receiving transmission portion including a bearing axle and a roller bearing mounted for rotation on the bearing axle; a latch assembly including a first latch and a second latch mounted in the latch hole and biased outwardly of the latch hole; A switchable rocker arm, wherein the bearing axle of a transmission portion that receives the cam includes the latch hole.

2. 2. The switchable rocker arm of claim 1, wherein the cam end diverges to form a first arm border portion including a first piston bore and a first end wall, and a second arm border portion including a second piston bore and a second end wall.

3. 3. The switchable rocker arm of claim 2, further comprising a piston assembly including a first piston seated in the first piston bore and a second piston seated in the second piston bore.

4. The switchable rocker arm of claim 3 , further comprising one or more travel-limiting structures including one or more travel stops configured to limit movement of the second body.

5. The switchable rocker arm of claim 3 , wherein the body includes a hydraulic supply configured to supply hydraulic fluid to the first piston bore and the second piston bore.

6. 10. The switchable rocker arm of claim 1, further comprising a lost motion spring mounted on a transmission that receives the cam.

7. 7. The switchable rocker arm of claim 6, further comprising a spring plate secured to said cam end and seating said lost motion spring.

8. The switchable rocker arm of claim 6 , wherein the cam receiving transmission is further configured to seat the lost motion spring.

9. The switchable rocker arm of claim 1 , wherein the cam receiving transmission portion includes a concave body configured to form a frame for the bearing axle.

10. The switchable rocker arm of claim 1 , wherein the second body is configured to be anchored to the pivot portion.

11. The switchable rocker arm of claim 10 , wherein the pivot portion includes a pair of rocker shaft bearings configured to rotate about the rocker shaft.

12. The switchable rocker arm of claim 10 further comprising a stamped sheet forming the concave body, the pivot portion, and the connecting body.

13. The switchable rocker arm of claim 12 , wherein the connector spans a portion of the body between a rocker shaft bore and the cam end.

14. A switchable rocker arm, comprising: a body configured to rotate about a rocker shaft and including a valve end and a cam end; a second body including a transmission portion that receives a cam and a latch hole that passes through the transmission portion that receives the cam; a latch assembly mounted in the latch hole; a spring frame including a first prong abutting a transmission portion that receives the cam and a second prong abutting a transmission portion that receives the cam; A switchable rocker arm, wherein the spring frame covers a transmission portion that receives the cam from a first side, and the second body includes a concave frame that covers the transmission portion that receives the cam from the first side.

15. The spring frame further includes a spring seat spanning between the first prong and the second prong.

16. 15. The switchable rocker arm of claim 14, wherein the cam end diverges to form a first arm border portion including a first piston bore and a first end wall, and a second arm border portion including a second piston bore and a second end wall.

17. 15. The switchable rocker arm of claim 14, further comprising a lost motion spring mounted on a transmission that receives the cam.

18. A switchable rocker arm, wherein the cam-receiving transmission portion further includes a bearing axle and a roller bearing mounted for rotation on the bearing axle, the bearing axle of the cam-receiving transmission portion including the latch hole.

19. A second body of the switchable rocker arm, a cam-receiving transmission including a bearing axle and a roller bearing mounted for rotation on said bearing axle; A pivot portion; a latch hole extending through a transmission portion that receives the cam and configured to receive a first latch and a second latch of a latch assembly, the first latch and the second latch being biased outwardly of the latch hole; the second body is configured to rotate relative to the switchable rocker arm body via the pivot portion; A second body of a switchable rocker arm, wherein the bearing axle of a transmission part that receives the cam includes the latch hole.

20. 20. The switchable rocker arm second body of claim 19, wherein the cam receiving transmission is operatively coupled to a lost motion spring mounted on the cam receiving transmission.

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