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 a second body. The lost motion spring may be integrated with the second body. Several pivot portions are shown as options for pivoting the second body relative to the body.

Background Art

[0002] The switchable rocker arm enables variable valve operation techniques such as cylinder deactivation in combustion machines. However, there are still problems regarding implementing the switching function within the narrow space of the machine.

Summary of the Invention

[0003] It has been found that the switchable rocker arm enables variable valve operation techniques such as cylinder deactivation and switched lift events such as early or late valve opening and closing, or valve opening and closing with higher or lower relative lift heights (e.g., EEVO, EEVC, LIVC, EIVO, NVO, iEGR, engine brake, etc.). A lightweight design is desirable to reduce the overall weight of the machine. It is desirable to manufacture integrally to facilitate installation on the machine as either an original manufacturing or replacement part. However, there are still problems regarding implementing the switching function within the narrow space of the machine.

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

[0005] In an additional embodiment, the switchable rocker arm may include a cam end that branches 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 may include a first piston seated in a first piston bore and a second piston seated in a second piston bore. The switchable rocker arm may include a hydraulic supply unit in its body, which is configured to supply hydraulic fluid to the first and second piston bores.

[0006] A lost motion spring can be mounted on top of the transmission unit. The lost motion spring can have a center of inertia that is balanced over the entire transmission unit. The spring plate can be fixed to the cam end and the lost motion spring can be seated there.

[0007] The transmission unit may include a bearing axle and a roller bearing mounted to rotate 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 outward from the latch hole.

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

[0009] The switchable rocker arm may include a spring frame comprising a first prong abutting the transmission, a second prong abutting the transmission, and a spring seating portion spanning between the first and second prongs. The spring frame may cover the transmission from the first side, and the second body may include a concave frame covering the transmission from the first side. Alternatively, the spring frame may cover the transmission from the first side, and the second body may include a concave frame covering the transmission from the second side.

[0010] Additional objectives and benefits are described to some extent in the following description, will become clearer from the description, or can be learned through practice of this disclosure. The objectives and benefits will also be realized and obtained by the elements and combinations pointed out in particular in the attached "Claims." [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view of a rocker arm. [Figure 2] Figure 1 is a cross-sectional view of a portion of the rocker arm, showing the latch assembly and piston assembly in the transmission region. [Figure 3] This is a diagram of the second main body. [Figure 4A] This is a comparison diagram of the second unit located on the main unit. [Figure 4B] This is a comparison diagram of the second unit positioned on the main unit, and Figure 4B shows the lost motion position. [Figure 4AA] The latch assembly is shown unlocked by the piston assembly. The second body is ready to move relative to the body. [Figure 4BB] The second body is shown moved in the direction of lost motion (indicated by the arrow). The movement of the second body is restricted by a combination of a movement stopping unit and a movement limiting unit. This combination is one of the options that enables other variable valve lift technologies. [Figure 5A] This shows an alternative second body. [Figure 5B] This shows an alternative second body. [Figure 6A] This shows an alternative second body. [Figure 6B] This shows an alternative second body. [Figure 6C] This shows an alternative second body. [Figure 7A] An alternative spring plate, body, and second body are shown. [Figure 7B] An alternative spring plate, body, and second body are shown. [Modes for carrying out the invention]

[0012] Here, the examples illustrated in the attached drawings are referenced in detail. Wherever possible, the same reference number will be used throughout the drawings to refer to the same or similar parts.

[0013] Several switchable rocker arms are illustrated to satisfy one or more objectives such as lightweight design, integrated assembly, and high-density mounting. Such switchable rocker arms 1-4 may comprise bodies 10, 11 configured to rotate around a rocker shaft. The bodies 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 or engine braking. 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 bore 135, 136. Preferably, the cam end 103 is branched to provide two piston bores 135, 136. Furthermore, the second main body 21-24 may be seated so as to pivot selectively between the branching portions of the cam end 103.

[0014] The second body sections 21-24 may include pivot sections 2140, 2240, 2340, and 2440, transmission sections 2130, 2230, 2330, and 2430 that receive the cam, and a latch hole 2132 that penetrates the transmission section. A latch assembly 60 is fitted into the latch hole 2132. A piston assembly 50 is fitted into at least one piston hole 135 or 136.

[0015] The main bodies 10 and 11 can be made lighter by including a hollow section. A rocker shaft hole 101 may be included and may or may not have a bushing for oriented the rocker arms 1 to 4 on the rocker shaft. The rocker shaft can supply hydraulic fluid to control the piston assembly 50. The hydraulic assembly 150 may be configured to have a hydraulic port 151, a hydraulic supply section 152, hydraulic outlets 153 and 154, and an optional leak port 155.

[0016] The switchable rocker arms 1-4 may include a cam end 103 that branches to form a first arm border portion 131 including a first piston hole 135 and a first end wall 133, and a second arm border portion 132 including a second piston hole 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 fitted into the first piston hole 135 and the second piston hole 136, as shown in the figure. Alternatively, one or both of the first piston holes 135 and the second piston holes 136 may be formed as blind holes so that the first and second end walls are formed integrally with the first arm border portion 131 and the second arm border portion 132. As an optional feature, the first arm border portion 131 and the second arm border portion 132 may have optional alignment posts or other mechanisms for fixing fastener receptacles 161, 162, or spring plates 31 or 32.

[0017] The piston assembly 50 can include a first piston 51 seated within a first piston bore 135 and a second piston 52 seated within a second piston bore 136. The switchable rocker arms 1-4 can include a hydraulic supply section 152 configured to supply hydraulic fluid to the first piston bore 135 and the second piston bore 136 within the bodies 10, 11. The hydraulic supply section 152 can include hydraulic outlets 153, 154 in fluid communication with the first piston bore 135 and the second piston bore 136. As one option, leak ports 155 may be cross-drilled through the first piston bore 135 and the second piston bore 136. The first piston bushing 53 and the second piston bushing 54 can further include oil cups 531, 541 for collecting pressurized fluid and oil supply sections 532, 542 cross-drilled to receive hydraulic control fluid for controlling the pistons 51, 52. The first piston bushing 53 and the second piston bushing 54 can include inner walls 534, 544 that function as movement restriction portions for the piston ends 515, 516. Optionally, a ground or other groove or port may be included in the first bushing 53 and the second bushing 54, and the pistons 51, 52 to facilitate distribution of the hydraulic control fluid. The inner walls 534, 544 can optionally be part of a piston bore of a blind hole type modification.

[0018] The pistons 51, 52 can include piston bodies 510, 520 having piston facings 511, 521. Optional protrusions 512, 522 or noses can be included in the piston facings 511, 512. The protrusions 512, 522 can function as movement stop portions that cooperate with the movement restriction portions 2161, 2162. The piston bodies 510, 520 may include pressure chambers 513, 523. By reducing the diameter of the pistons 51, 52, it is possible to reduce the volume of the hydraulic control fluid and operate with a high response time.

[0019] Instead of the overhead reaction bar, a lost motion spring 40 can be mounted on the transmission parts 2130, 2230, 2330, 2430. The lost motion spring 40 can have a center of inertia that is balanced with respect to the entire transmission parts 2130, 2230, 2330, 2430. The spring plates 31, 32 can be fixed to the cam end 103 to seat the lost motion spring 40. The first spring end 41 can be biased against a part of the second bodies 21-24, and the second spring end 42 can be biased against the spring plates 31, 32. Thereby, the second bodies 21-24 are biased towards a position where the latch assembly 60 can latch engage within the piston holes 135, 136.

[0020] The spring plates 31, 32 can include spring plate ends 311, 312 or 321, 322 configured to couple to a branched body. For example, the first and second arm borders 133, 134 can include fastener receptacles 161, 162 for receiving fasteners 61, 62 such as screws or rivets. Alternatively, the spring plates 31, 32 can be fixed using welding. Alternatively, prongs, pins, screws, etc. can project from the first and second arm borders 133, 134 to receive nuts or caps. The spring plates 31, 32 can include a lost motion seating portion 33 having optional protrusions or grooves for positioning the second spring end 42. Instead of a continuous sheet material, a cage configuration having cage arms 323, 324 can be had. To provide a track for the spring force of the lost motion spring 40, the spring plate 31 can be straight in a square configuration (Figs. 1, 2, 4A-6A, 6C), or the spring plate 32 can be oblique in an angled configuration (Figs. 7A, 7B).

[0021] The transmission units 2130, 2230, 2330, and 2430 may include a bearing axle 2131 and a roller bearing 2134 mounted to rotate on the bearing axle 2131. An optional needle bearing may be included between the roller bearing 2134 and the bearing axle 2131. An alternative is a slider pad integrated with the bearing axle 2131. 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 outward from the latch hole 2132. If only one piston 51 or 52 is used, it is considered that only one latch 61 or 62 is required. A blind hole, snap ring, bushing, or other stay may be used to bias one latch 61 or 62 in the direction of one piston 51 or 52. However, as shown in the figure, the latch spring 615 can push the latch ends 613 and 623 apart to form a latch cavity 616. The latch spring 615 can seat in the spring cups 614 and 624 within the latch bodies 611 and 621. The latch facings 612 and 622 face the pistons 51 and 52, compressing the latch spring 615 using a hydraulically controlled fluid, and pushing the pistons 51 and 52 into the piston holes 135 and 136 until the latch ends 612 and 623 make contact. Other movement limiting parts such as bushings, cast walls, and snap rings may be used for the latches 61 and 62. In this configuration, it is possible to provide a dry latch hole 2132 that does not use a hydraulically controlled fluid. The second bodies 21 to 24 may be lubricated via the piston holes 135 and 136 or via the hydraulic supply parts within the bodies 10 and 11, or they may not be lubricated at all. The rotating cam is lubricated via the main bodies 10 and 11, but does not need to be lubricated via the second main bodies 21 to 24, thereby making the second main bodies 21 to 24 lighter and simpler.

[0022] In the first configuration, the second body 21 can be coupled to pivot mounts 141, 142 via a pivot axle 143. The pivot region 140 is located near the cam end 103 and is formed by a portion of the body 10 that connects to the pivot portion 2140 of the second body 21. The second body 21 may include pivot mounts 2141, 2142 for connection to the pivot axle 143. The transmission section 2130 may include a concave body 211 configured to form the frame of the bearing axle 2131. The ends 2135, 2136 of the bearing axle 2131 can be fixed in bearing slots 216, 217. The concave body may span above the transmission section 2130 and include connecting beams 212, 213 for seating the lost motion spring 40. Struts 214, 215 may extend from the connecting beams 212, 213 to include the bearing slots 216, 217. Optional platform sockets 218, 219 can extend from struts 214, 215 or connecting beams 212, 213 to form pivot points for the spring platform 2131. The spring platform 2131 can seat the lost motion spring 40 by an optional spring guide 2132 (which may alternatively be a groove or other guide). Platform guides 2133, 2134 can extend into the platform sockets 218, 219 to pivot the spring platform 2131. The plate portion 2135 can pivot or swing when the lost motion spring 40 is contracted (Figure 4BB) or extended back to the latched position (Figure 2). Thus, the transmission portion 2130 can be configured to seat the lost motion spring 40. The second body 21 may be configured to be anchored to the pivot portion 140. The second arm 21 may include a concave body 211, a second pivot portion 2140, and stamped sheets forming connecting beams 212 and 213.

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

[0024] In Figures 5A and 5B, the transmission section 2230 may include a concave body 221 configured to form the frame of the bearing axle 2131. This concave body 221 is configured to have connecting beams 222, 223 that form the frame of the roller bearing 2134 from the lower side (the second side relative to the spring platform 2131). The struts 224, 225 include bearing slots 226. A drop-in assembly method for the bearing axle 2131 can be further facilitated. A connector 228 extends from the concave body 221. Side arms 2282, 2283 extend from the connector 228, and the side arms 2282, 2283 may include pivot mounts 2241, 2242 in the form of rocker shaft bearings. The pivot mounts 2241, 2242 of the pivot section 2240 are positioned at the same location as the rocker shaft hole 101 so that the rocker shaft can function as the pivot position for both the main body 11 and the second main body 22. The second body 22 is very lightweight because it can be formed from stamped sheet material. This allows for cost reduction. The transmission section 2230 can be further configured to seat the lost motion spring 40. The spring platform 2231 may include a plate section 2237 having an optional spring guide 2232. Platform struts 2233, 2234 having platform bearing slots 2235 may extend from the plate section 2237. The spring platform 2231 can be mounted on a bearing axle 2131. The platform bearing slots 2235 can be designed to secure the bearing axle 2131. Thus, the second body 22 can be configured to be anchored to a pivot section 2240, in this case to a rocker shaft. The pivot section 2240 may include a pair of rocker shaft bearings as pivot mounts 2241, 2242 configured to rotate around the rocker shaft. The second arm 22 may include a concave body 221, a pivot portion (pivot mounts 2241, 2242), and a stamped sheet forming a connector 228.The connector 228 may be spanned across the portion of the body 11 between the rocker shaft hole 101 and the cam end 103. The spring frame (spring platform 2231) may cover the transmission section 2230 from the first side, and the second body 22 may include a concave frame 221 that covers the transmission section 2230 from the second side.

[0025] In Figures 6A and 6B, the transmission section 2330 may include a concave body 231 configured to form the frame of the bearing axle 2131. This concave body 231 is configured to have connecting beams 232 and 233 that form the frame of the roller bearing 2134 from the upper side (first side relative to the spring platform 2231). Struts 234, 2324, 235, and 2325 are attached to beams 239 and 2329 to form the bearing slots 236. A drop-in assembly method for the bearing axle 2131 can be further facilitated. A connector 238 extends from the concave body 231. A bracket 2381 extends upward, covering a portion of the main body 11. Side arms 2382 and 2383 extend from the bracket 2381 of the connector 238, and the side arms 2382 and 2383 may include pivot mounts 2341 and 2342 in the form of rocker shaft bearings. The pivot mounts 2341 and 2342 of the pivot section 2340 are positioned at the same location as the rocker shaft hole 101 so that the rocker shaft can function as the pivot position for both the main body 11 and the second main body 23. The second main body 23 is very lightweight because it can be formed from stamped sheet material. This allows for cost reduction. The transmission section 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 be mounted on the bearing axle 2131. The platform bearing slot 2235 can be designed to secure the bearing axle 2131. Thus, the second main body 23 can be configured to be anchored to the pivot section 2340, in this case to the rocker shaft. The pivot section 2340 may include a pair of rocker shaft bearings as pivot mounts 2341 and 2342 configured to rotate around the rocker shaft. The second arm 23 may include a concave body 231, a pivot portion (pivot mounts 2341, 2342), and a stamped sheet forming a connector 238.The connector 238 may span across the 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 contacting the transmission section 2330, a second prong formed by a strut 2234 for contacting the transmission section 2230, and a spring seating portion formed by a plate portion 2237 spanned between the first and second prongs. The spring frame (spring platform 2231) may cover the transmission section 2230 from the first side, and the second body 23 may include a concave frame 231 that covers the transmission section 2230 from the first side.

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

[0027] The concave bodies 211, 221, 231, and 241 are formed from stamped sheets, but other techniques such as machining, cold forming, and casting 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 obvious to those skilled in the art by considering the specifications and practices of the examples disclosed herein.

Claims

1. A switchable rocker arm, A body, which is configured to rotate around a rocker shaft, and includes a valve end and a cam end, A second body comprising a transmission section for receiving a cam and a latch hole passing through the transmission section for receiving the cam, wherein the transmission section for receiving the cam includes a bearing axle and a roller bearing mounted to rotate on the bearing axle, A latch assembly comprising a first latch and a second latch, which are mounted in the latch hole and biased outward from the latch hole, The bearing axle of the transmission unit that receives the cam includes the latch hole, A switchable rocker arm, wherein the cam end is branched to form a first arm border portion including a first piston hole and a first end wall, and a second arm border portion including a second piston hole and a second end wall.

2. A switchable rocker arm according to claim 1, further comprising a piston assembly including a first piston seated in a first piston bore and a second piston seated in a second piston bore.

3. The switchable rocker arm according to claim 2, further comprising one or more movement-restricting structures including one or more movement-stopping parts configured to restrict the movement of the second body.

4. The switchable rocker arm according to claim 2, wherein the main body includes a hydraulic supply unit configured to supply hydraulic fluid to the first piston hole and the second piston hole.

5. A switchable rocker arm according to claim 1, comprising a lost motion spring mounted on a transmission unit that receives the cam.

6. The switchable rocker arm according to claim 5, comprising a spring plate fixed to the cam end and seating the lost motion spring.

7. The switchable rocker arm according to claim 5, wherein the transmission unit that receives the cam is further configured to seat the lost motion spring.

8. The switchable rocker arm according to claim 1, wherein the transmission portion that receives the cam includes a concave body configured to form the frame of the bearing axle.

9. The switchable rocker arm according to claim 1, wherein the second body is configured to be connected to a pivot portion.

10. The switchable rocker arm according to claim 9, wherein the pivot portion includes a pair of rocker shaft bearings configured to rotate around the rocker shaft.

11. The switchable rocker arm according to claim 9, further comprising a stamped sheet forming a concave body, the pivot portion, and a connecting body.

12. The switchable rocker arm according to claim 11, wherein the connecting body spans the portion of the main body between the rocker shaft hole and the cam end.

13. A switchable rocker arm, A body, which is configured to rotate around a rocker shaft, and includes a valve end and a cam end, A second body including a transmission part that receives a cam and a latch hole that penetrates the transmission part that receives the cam, A latch assembly that is fitted into the latch hole, The device comprises a spring frame including a first prong that contacts the transmission portion that receives the cam, and a second prong that contacts the transmission portion that receives the cam, A switchable rocker arm, wherein the spring frame covers a transmission section that receives the cam from the first side, and the second body includes a concave frame that covers the transmission section that receives the cam from the first side.

14. The switchable rocker arm according to claim 13, wherein the spring frame further includes a spring seating portion spanning between the first prong and the second prong.

15. The switchable rocker arm according to claim 13, wherein the cam end is branched to form a first arm border portion including a first piston hole and a first end wall, and a second arm border portion including a second piston hole and a second end wall.

16. A switchable rocker arm according to claim 13, further comprising a lost motion spring mounted on a transmission unit that receives the cam.

17. The switchable rocker arm according to claim 13, wherein the transmission unit that receives the cam further includes a bearing axle and a roller bearing mounted to rotate on the bearing axle, and the bearing axle of the transmission unit that receives the cam includes the latch hole.

18. The second body of the switchable rocker arm, A transmission unit for receiving a cam, including a bearing axle and a roller bearing mounted to rotate on the bearing axle, The pivot section, The transmission portion that receives the cam penetrates the latch hole, which is configured to receive the first latch and the second latch of the latch assembly, and the first latch and the second latch are biased outward from the latch hole, The second body is configured to rotate relative to the body of the switchable rocker arm via the pivot portion, The bearing axle of the transmission unit that receives the cam includes the latch hole, The transmission unit that receives the cam is operably coupled to a lost motion spring mounted on the transmission unit that receives the cam, and is the second body of a switchable rocker arm.

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