Sleeved rocker shaft for type III heavy duty valve train

Abstract

A rocker shaft assembly configured to support a rocker arm and deliver oil to the rocker arm and related method of making is provided. The rocker shaft assembly includes a core shaft and a sleeve. The core shaft has a core body including a main oil supply channel formed thereon. The sleeve has passages formed thereon. The sleeve is disposed around the core shaft. The main oil supply channel aligns with at least one of the passages on the sleeve. The main oil supply is milled into the core shaft.

Claims

1. A rocker shaft assembly configured to support a rocker arm and deliver oil to the rocker arm, the rocker shaft assembly comprising: a core shaft having a core body including at least two oil supply channels formed thereon; and a sleeve having passages formed thereon; wherein the sleeve is disposed around the core shaft, each of the at least two oil supply channels aligning with at least one passage of the passages on the sleeve, wherein the at least two oil supply channels are axially spaced-apart from each other, wherein the core body further defines a brake oil supply channel and wherein at least one passage of the passages aligns with the brake oil supply channel, and wherein the core body further defines at least one of a variable valve lift (VVL) and cylinder deactivation (CDA) channel formed thereon and wherein at least one passage of the passages aligns with the at least one of the VVL and CDA channel.

2. The rocker shaft assembly of claim 1, wherein the core shaft is press fit into the sleeve.

3. The rocker shaft assembly of claim 1, wherein the at least two oil supply channels are milled around an outer diameter of the core shaft.

4. The rocker shaft assembly of claim 3, wherein the at least two oil supply channels are in the form of a groove.

5. The rocker shaft assembly of claim 1, wherein the brake oil supply channel and the cylinder deactivation channel is milled around an outer diameter of the core shaft.

6. The rocker shaft assembly of claim 5, wherein the brake oil supply channel and the cylinder deactivation channel are in the form of grooves.

7. The rocker shaft assembly of claim 1, wherein the core shaft and sleeve are both formed of metal.

8. The rocker shaft assembly of claim 1, wherein the passages on the sleeve are cross drilled into the sleeve.

9. A rocker shaft assembly configured to support a rocker arm and deliver oil to the rocker arm, the rocker shaft assembly comprising: a tube assembly having a main supply tube and at least one of a brake oil supply tube, a variable valve lift (VVL) tube and a cylinder deactivation (CDA) tube; a sleeve having passages formed thereon; and at least one separator plate engaging the tube assembly for positioning the main supply tube and at least one of the brake oil supply tube, the variable valve lift (VVL) tube and the cylinder deactivation (CDA) tube relative to each other, wherein the sleeve is disposed around the tube assembly, wherein the passages intersect the main supply tube and the at least one of the brake oil supply tube, the VVL tube and the CDA tube.

10. The rocker shaft assembly of claim 9, further comprising an overmold between the sleeve and the tube assembly.

11. A rocker shaft assembly configured to support a rocker arm and deliver oil to the rocker arm, the rocker shaft assembly comprising: a core shaft having a core body including at least two oil supply channels formed thereon; and a sleeve having passages formed thereon; wherein the sleeve is disposed around the core shaft, each of the at least two oil supply channels aligning with at least one passage of the passages on the sleeve, wherein the at least two oil supply channels are axially spaced-apart from each other, and wherein one of the at least two oil supply channels is curved or bent in a circumferential direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

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

(2) FIG. 1 is a perspective view of a partial valve train assembly incorporating a rocker arm assembly configured to rotate around a rocker shaft received in a rocker housing according to one prior art example;

(3) FIG. 2 is a perspective view of a rocker shaft constructed in accordance to one prior art example;

(4) FIG. 3A is cross-sectional view of the prior art rocker shaft of FIG. 2;

(5) FIG. 3B is an end view of the prior art rocker shaft of FIG. 2;

(6) FIG. 4 is a sleeved rocker shaft assembly including a core shaft and a sleeve constructed in accordance to one example of the present disclosure;

(7) FIG. 5 is a perspective view of the core shaft of FIG. 4 showing a main oil supply;

(8) FIG. 6 is a side view of the core shaft of FIG. 4 and showing a brake oil supply channel and cylinder deactivation (CDA) oil supply channels;

(9) FIG. 7A is a cross-sectional view of the rocker shaft of FIG. 3A;

(10) FIG. 7B is a cross-sectional view of the core shaft of FIG. 4;

(11) FIG. 8 a sleeved rocker shaft assembly including a core shaft and a sleeve constructed in accordance to a second example of the present disclosure;

(12) FIG. 9 is a first side view of the core shaft of the sleeved rocker shaft assembly of FIG. 8;

(13) FIG. 10 is a second side view of the core shaft of the sleeved rocker shaft assembly of FIG. 8;

(14) FIG. 11 a sleeved rocker shaft assembly including a tube assembly and a sleeve constructed in accordance to a third example of the present disclosure;

(15) FIG. 12 is a side view of a tube assembly of the sleeved rocker shaft assembly of FIG. 11;

(16) FIG. 13 is a perspective view of a separator plate used in the tube assembly of FIG. 12;

(17) FIG. 14 is a partial perspective view of the sleeve of the sleeved rocker assembly of FIG. 11;

(18) FIG. 15 is a partial perspective view of the sleeved rocker shaft assembly of FIG. 11; and

(19) FIG. 16 is a partial sectional view of the sleeved rocker shaft assembly of FIG. 11.

DETAILED DESCRIPTION

(20) With initial reference to FIG. 1, a partial valve train assembly constructed in accordance to one prior art example is shown and generally identified at reference 10. The partial valve train assembly 10 utilizes variable valve actuation and is shown configured for use in a three-cylinder bank portion of a six-cylinder engine. The partial valve train assembly 10 can include a rocker assembly housing 12 that supports a series of rocker arm assemblies 14 (only one rocker arm assembly is shown for simplicity). A rocker shaft 20A is received by the rocker housing 12. The rocker shaft 20A cooperates with the rocker arm assemblies 14 to communicate oil to the rocker arm assemblies 14 during variable valve actuation events.

(21) FIGS. 2-3A illustrate another rocker shaft 20B constructed in accordance to another prior art example. The rocker shaft 20B includes a shaft body 30 having a plurality of oil channels 32 including an oil supply channel 34 and oil delivery channels 38. The oil supply channel 34 includes a long continuous supply channel 44. Similarly, the oil delivery channels 38 include long continuous supply channels 48. The rocker shaft 20B further includes bolt holes 50 and end plugs 52. Plugs or dividers 54 can be arranged to separate controls between the oil control valves. The prior art rocker shaft 20B presents many drawbacks. For example, the rocker shaft 20B requires long manufacturing time for drilling the oil channels 44 and 48. Drilling along extended paths can be referred to as gun drilling and can be challenging as the length of the drill path gets longer. In some examples the bores can be greater than 400 mm. The process capability for precise positional tolerances on long drillings is difficult. It is also challenging to add support bolts (such as identified at phantom line 56) other than shaft end due to sealing issues. This can limit the design to carrier style mounts. The stiffness of the rocker shaft can be reduced due to the oil passages. It is difficult to maintain the minimum wall thickness between the oil holes and the oil holes to the outer diameter of the rocker shaft. Additionally, a failure mode is associated with the end plugs 52. Moreover, manufacturing costs for creating the rocker shaft 20B are high.

(22) As used herein, the following disclosure is described in the context of valve applications having cylinder deactivation and engine brake. However, the disclosures herein are equally applicable for other variable valve applications where the cylinder deactivation arm is replaced with a variable valve lift (WL) arm that alters the valve motion. With reference to FIGS. 4-6, a rocker shaft assembly constructed in accordance to a first example of the present disclosure is shown and generally identified at reference 120. The rocker shaft assembly 120 includes a core shaft 122 and a sleeve 124. In one example, the core shaft 122 and the sleeve 124 are both formed of metal. The core shaft 122 and the sleeve 124 can be manufactured separately and the core shaft 122 can be subsequently pressed into the sleeve 124. The core shaft 122 generally includes a core body 130 having a main supply channel 140, a brake oil supply channel 142 and variable valve applications such as cylinder deactivation (CDA) channels 144 formed therein.

(23) The main supply channel 140, the brake oil supply channel 142 and the CDA channels 144 can be milled. A milling process will not require heat treatment. It will be appreciated that the orientation and placement of the main supply channel 140, brake oil supply channel 142 and the CDA channels 144 is merely exemplary and that these channels may be milled in different locations on the core shaft 122.

(24) The sleeve 124 can include passages 150 that are cross drilled. The sleeve 124 can be press fit on the core shaft 122. The rocker shaft assembly 120 provides advantages over the prior art rocker shafts 20A, 20B. The rocker shaft assembly 120 is easier and more cost effective to manufacture. Gun drilling is replaced with cheaper milling. The positional tolerances between the communication passages is relaxed. The occurrence of thin wall or wall breakage between oil routings is eliminated. The geometries of the oil passages is more flexible. Stiffness is improved. The cylinder deactivation channel dividers are built into the rocker shaft assembly 120 so no oil leakage from prior art plugs or pressed dowels can occur. FIGS. 7A and 7B show a comparison of the prior art rocker arm shaft 20B (FIG. 7A) and the core shaft 122 of the present disclosure.

(25) With reference to FIGS. 8-10, a rocker shaft assembly constructed in accordance to a second example of the present disclosure is shown and generally identified at reference 220. The rocker shaft assembly 220 includes a core shaft 222 and a sleeve 224. In one example, the core shaft 222 and the sleeve 224 are both formed of metal. The core shaft 222 and the sleeve 224 can be manufactured separately and the core shaft 222 can be subsequently pressed into the sleeve 224. The core shaft 222 generally includes a core body 230 having a main supply channel 240, a brake oil supply channel 242 and variable valve lift (VVL) or cylinder deactivation (CDA) channels 244 formed therein.

(26) The main supply channel 240, the brake oil supply channel 242 and the CDA channels 244 can be milled. The core shaft 222 will not require heat treatment. The sleeve 224 is the wear resistance part and will require heat treatment or coating. It will be appreciated that the orientation and placement of the main supply channel 240, brake oil supply channel 242 and the CDA channels 244 is merely exemplary and that these channels may be milled in different locations on the core shaft 222.

(27) The sleeve 224 can include passages 250 that are cross drilled. The sleeve 224 can be press fit on the core shaft 222. The rocker shaft assembly 220 provides advantages over the prior art rocker shafts 20A, 20B. The rocker shaft assembly 220 is easier and more cost effective to manufacture. Gun drilling is replaced with cheaper milling. The positional tolerances of the longitudinal milled oil passages is relaxed versus gun drilling. The positional tolerances of the communication holes 150 are similar between the processes. The occurrence of thin wall or wall breakage between oil routings is eliminated. The geometries of the oil passages is more flexible and allows changes in shape, smooth bends and transition to improve oil flow. Stiffness is improved due to possibility for additional supporting bolts and cross holes 56. The cylinder deactivation channel dividers are built into the rocker shaft assembly 220 so no oil leakage from prior art pressed plugs or dowels can occur.

(28) With reference to FIGS. 11-16, a rocker shaft assembly constructed in accordance to a third example of the present disclosure is shown and generally identified at reference 320. The rocker shaft assembly 320 includes a tube assembly 322 and a sleeve 324. In one example, the sleeve 324 is formed of metal. The tube assembly 322 and the sleeve 324 can be manufactured separately and the tube assembly 322 can be subsequently installed into the sleeve 324. In one example, the sleeve 324 can be over molded around the tube assembly 322. The tube assembly 322 generally includes a main supply gallery or main supply tube 340, a brake oil supply gallery or brake supply tube 342 and a variable valve (VVA) or cylinder deactivation (CDA) gallery or CDA tube 344. A series of separator plates 358 can be arranged to locate the respective tubes 340, 342 and 344 relative to each other.

(29) The sleeve 324 can include passages 350 that are cross drilled. The tube assembly 322 can be inserted into the sleeve 324. Through holes can be drilled into the sleeve that intersect the respective tubes 340, 342 and 344 for oil communication. The respective tubes 340, 342 and 344 can be pinched or staked at areas 352 to stop oil flow at desired locations. The tubes can have non-round cross-sections maximizing clearance with the sleeve 324. The rocker shaft assembly 320 provides advantages over the prior art rocker shafts 20A, 20B similar to those described above. The rocker shaft assembly 320 is easier and more cost effective to manufacture. Further, long drilling is replaced with cheaper tubes. In some examples the tubes can be commodity tubes similar to brake lines or other commonly available hydraulic tubes.

(30) In one assembly process, the tubes 340, 342 and 344 can be stacked onto the separator plates 358. The tube assembly 322 and separator plates 358 can collectively be referred to as a tube subassembly 368. The tube subassembly 368 can be inserted into the sleeve 324. The sleeve 324 can have the passages 350 prearranged before accepting the tube assembly 368. Next, the tube subassembly can have an overmold 370 to capture the tube subassembly 368 within the sleeve 324. Holes 374 can then be drilled into the respective tubes 340, 342 and 344 using the passages 350 in the sleeve 324 as a guide for the drilling. In this regard, a drill can be aligned through the passages 350 to intersect each of the respective tubes 340, 342 and 344 to create the holes 374 in the respective tubes 340, 342 and 344. The overmold 370 provides a sealant.

(31) The foregoing description of the examples has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular example are generally not limited to that particular example, but, where applicable, are interchangeable and can be used in a selected example, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.