Patent Application
20100050974
The present disclosure relates to engine valvetrain assemblies and more specifically to the fixation of valvetrain assemblies to an engine.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Engine valvetrains may include rocker bar assemblies that rotatably support valve actuating devices such as rocker arms. Engine rocker bar assemblies may be fixed to a cylinder head of an engine through a bolted engagement. However, the load applied to the rocker bar assemblies by the valve actuating devices may exceed the load that the cylinder head mounting location can withstand.
An engine assembly may include an engine block, a cylinder head, and a valvetrain assembly. The cylinder head may be fixed to the engine block. The valvetrain assembly may include a valve actuating member, a support member, and a first fastener engaged with the support member and the engine block that fixes the support member to the engine block. The valve actuating member may be rotatably supported on the support member.
Additionally, the cylinder head may be located between the support member and the engine block and the first fastener may extend through the cylinder head to engage the engine block. The valvetrain assembly may include a second fastener having a threaded region and the cylinder head may include a threaded bore engaged with the threaded region of the second fastener.
A valvetrain assembly may include a support member, a valve actuating mechanism, and a first fastener. The valve actuating member may be rotatably supported on the support member. The first fastener may extend through a cylinder head of an engine and engage an engine block of the engine to fix the support member to the engine block.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
Referring now to
The rocker bar assemblies 26 may form a support member for the valve actuating assemblies 28 and may include a support bar 32, rocker shafts 34, spacers 36, a set of first fasteners 38, a set of second fasteners 40, and first and second sets of nuts 42, 44. The valve actuating assemblies 28 may take a variety of forms. In the present example, the valve actuating assemblies 28 are in the form of rocker arms.
The valvetrain assembly 18 associated with each of the first and second cylinder heads 14, 16 may be generally similar to one another. Therefore, the valvetrain assembly 18 will be described with respect to the first cylinder head 14 with the understanding that the description applies equally to the second cylinder head 16. The support bar 32 may be fixed to the first cylinder head 14 and the engine block 12 and may include a main body portion 46 having a series of legs 48 extending from the main body portion 46.
A first set of openings 50 may extend through the main body portion 46 and the legs 48 and a second set of openings (not shown) may extend through the main body portion 46. The second set of openings may be offset from and disposed at an angle relative to the first set of openings 50. The rocker shafts 34 may include a series of openings (not shown) aligned with the second set of openings in the support bar 32. The rocker shafts 34 may each support a first and second valve actuating assembly 28 and may be fixed to the support bar 32.
Each of the first fasteners 38 may include a shaft 56 having first and second ends 58, 60. The shaft 56 may include a first threaded region 62 near the first end 58, a second threaded region 64 at an intermediate portion, and a third threaded region 66 at the second end 60. The second end 60 may additionally include a recess 68 extending axially into the shaft 56, as illustrated in
The spacers 36 may include an unthreaded bore 37 and may be located between the legs 48 of the support bar 32 and the first cylinder head 14. A first fastener 38 may be located at each end of the support bar 32, as well as between pairs of intake and exhaust valves 22, 24. The engagement between one of the first fasteners 38, the support bar 32, the first cylinder head 14, and the engine block 12 will be discussed below with the understanding that the description applies equally to the remainder of the first fasteners 38. The first fastener 38 may extend through the first set of openings 50 in the support bar 32, the spacer 36, the first cylinder head 14, and the engine block 12. More specifically, the engine block 12 may include a threaded bore 72 engaged with the first threaded region 62 of the first fastener 38.
The second threaded region 64 may be located between the spacer 36 and the first cylinder head 14. The second threaded region 64 may be engaged with the first nut 42 and the first nut 42 may abut the first cylinder head 14. The first cylinder head 14 may be fixed to the engine block 12 by the engagement between the first fastener 38 and the engine block 12 and the engagement between the first nut 42 and the first cylinder head 14.
The second end 60 of the first fastener 38 may extend through the first opening 50 and above the support bar 32. More specifically, the third threaded region 66 may extend above the support bar 32 and may be engaged with the second nut 44. The second nut 44 may abut the support bar 32 and may cooperate with the first fastener 38 to directly couple the rocker bar assembly 26 to the engine block 12. In the present example, the first fastener 38 may be free from threaded engagement with the first cylinder head 14.
The set of second fasteners 40 may extend through the second set of openings in the support bar 32 and the openings in the rocker shaft 34 and may be engaged with the first cylinder head 14. The engagement between the set of second fasteners 40 and the first cylinder head 14 may include a threaded engagement between the second fastener 40 and a threaded bore (not shown) of the first cylinder head 14. A longitudinal axis (L1) of the first fastener 38 may extend at an angle (θ) relative to the longitudinal axis (L2) of the second fastener 40. The angular disposition of the first and second fasteners 38, 40 relative to one another may provide increased structural support for the load applied to the rocker bar assembly 26 by the valve actuating assemblies 28.
During assembly, the first fastener 38 may be placed through the cylinder head 14 and into the engine block 12. The first threaded region 62 of the first fastener 38 may be threaded into the threaded bore 72 of the engine block 12. Next, the first nut 42 may be threaded onto the second threaded region 64 of the first fastener 38 to fix the cylinder head 14 to the engine block 12. The spacer 36 may then be slid onto the first fastener 38. Next, the support bar 32 may be located on the first fastener 38. The second nut 44 may then be threaded onto the third threaded region 66 of the first fastener 38 to fix the rocker bar assembly 26 to the engine block 12. The second fastener 40 may then be located in the support bar 32 and the rocker shaft 34 and threaded into the cylinder head 14.
