Patent Publication Number: US-8992358-B2

Title: Automotive timing chain system component and method thereof

Description:
This application claims the benefit of U.S. Provisional Application Ser. No. 61/156,200 filed Feb. 27, 2009. 
    
    
     TECHNICAL FIELD 
     The technical field generally relates to products including automotive timing chain system components that bear against chains of automotive timing chain systems. 
     BACKGROUND 
     An automotive timing chain system transfers rotation from a crankshaft to a camshaft in an automotive internal combustion engine, and can also drive other components such as an oil pump, water pump, and/or fuel injection pump. Components, such as tensioner arms or chain guides, are commonly used in the system to help keep an associated chain taut by taking up slack in the chain, and to help direct the chain along its path. Conventionally, the components are made by a casting, stamping, or extrusion process. 
     SUMMARY OF EXEMPLARY EMBODIMENTS OF THE INVENTION 
     One exemplary embodiment includes a product which may include an automotive timing chain system component. In use, the component may bear directly or indirectly against a chain of an automotive timing chain system. The component may have an elongated body made into a generally hollow shape by a hydroforming process. The body may have a first open free end, a second open free end, and an upper wall. The upper wall may extend along the length of the body from the first open free end to the second open free end. 
     One exemplary embodiment includes a product which may include a tensioner arm for an automotive timing chain system. The tensioner arm may include a body made into a generally hollow shape by a hydroforming process. The tensioner arm may also include a sliding piece mechanically interconnected to the body. In use, the sliding piece may bear directly against a chain of the automotive timing chain system. 
     One exemplary embodiment includes a method which may include hydroforming a body of an automotive timing chain system component into a generally hollow and elongated shape. The body may have an upper wall extending along the length of the body. The body may also have one or more opening(s) located in the upper wall. The method may include forming a sliding piece that, in use, bears directly against a chain of an automotive timing chain system. The sliding piece may have one or more finger(s). The method may include connecting the body and the sliding piece by inserting the finger(s) into the opening(s). 
     Other exemplary embodiments of the invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while disclosing exemplary embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a schematic of an exemplary embodiment of an automotive timing chain system. 
         FIG. 2  is a perspective view of an exemplary embodiment of a tensioner arm. 
         FIG. 3  is a sectional view taken along line  3 - 3  of  FIG. 2 , showing a cross-sectional profile thereat. 
         FIG. 4  is a fragmented view of an exemplary embodiment of a tensioner arm. 
         FIG. 5  is a sectional view taken along line  5 - 5  of  FIG. 4 , showing a cross-sectional profile thereat. 
         FIG. 6   a  is a sectional view taken along line  6 - 6  of  FIG. 2 , showing a cross-sectional profile of a first exemplary embodiment of a body thereat. 
         FIG. 6   b  is a sectional view taken along line  6 - 6  of  FIG. 2 , showing a cross-sectional profile of a second exemplary embodiment of a body thereat. 
         FIG. 6   c  is a sectional view taken along line  6 - 6  of  FIG. 2 , showing a cross-sectional profile of a third exemplary embodiment of a body thereat. 
         FIG. 6   d  is a sectional view taken along line  6 - 6  of  FIG. 2 , showing a cross-sectional profile of a fourth exemplary embodiment of a body thereat. 
         FIG. 7  is an exploded view of the tensioner arm of  FIG. 2 . 
         FIG. 8  is a sectional view of the tensioner arm of  FIG. 2 . 
         FIG. 9  is a sectional view taken along line  9 - 9  of  FIG. 2 . 
         FIG. 10  is an exploded view of an exemplary embodiment of a chain guide. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The following description of the embodiment(s) is merely exemplary (illustrative) in nature and is in no way intended to limit the invention, its application, or uses. 
     The figures illustrate an exemplary embodiment of an automotive timing chain system component, such as a tensioner arm  10  or a chain guide  12 , that is used in an automotive timing chain system  14  for an internal combustion engine. The component may have a body  16  and a sliding piece  18 . The body  16  may be a seamless tube manufactured at least in part by a hydroforming process. The body  16  may thus be made of a lower-grade, cheaper, and/or lighter material than a conventionally cast, stamped, or extruded component while maintaining required strength and structure. The body  16  may also have a reduced size, such as a reduced height, as compared to the conventional component. 
     In the illustrated embodiment of  FIG. 1 , the automotive timing chain system  14  may include the tensioner arm  10 , the chain guide  12 , a plunger  20 , a chain  22 , and one or more idler pulleys  24 . The plunger  20  may contact and exert a force against the tensioner arm  10  to keep the chain  22  taut. The plunger  20  may take many forms and arrangements including a hydraulically-actuated plunger, an electrically-actuated plunger, a mechanical-spring plunger, or another suitable type. The automotive timing chain system  14  may too take many forms and arrangements other than that described and shown here. 
     In the illustrated embodiment of  FIGS. 1-9 , the body  16  of the tensioner arm  10  may be constructed to withstand forces exerted directly or indirectly on it from the plunger  20  and from the chain  22 . In one embodiment, the body  16  may have about a 1.5 mm generally uniform wall thickness, and may be made out of a relatively low-grade material such as an SAE 1008 (HRB40) steel; of course other thicknesses and materials are possible. As mentioned, the body  16  may be made primarily by a hydroforming process. Other preliminary and subsequent metalworking processes may also be performed such as bending and cutting processes. The exact hydroforming process performed may depend on, among other things, properties such as strength and wall thickness of the material used, and the desired end shape of the body  16 . 
     In one example, a tubular blank may be initially cut to a desired size and may be placed in a hydroforming machine between a pair of die halves. The ends of the tubular blank may then be sealed. In one case, the die halves may be closed over the tubular blank, an internal hydraulic pressure may be applied inside of the blank, and the blank may expand to take on the shape of the closed die halves. In another case, a first internal hydraulic pressure may be applied inside of the tubular blank, the die halves may be progressively closed thus progressively deforming the blank, and, once completely closed, a second relatively increased internal hydraulic pressure may be applied and the blank may elongate to take on the shape of the closed die halves. The hydroforming process may differ in other cases. 
     Once formed, the body  16  may have a hollow shape and structure, and may be seamless along its length. The body  16  may be elongated in a longitudinal (lengthwise) direction and may extend longitudinally from a first open free end  26  to a second open free end  28 . The body  16  may be curved with multiple tangent radii or may be generally straight in the longitudinal direction, and may have an internal channel  30  which may vary in cross-sectional profile in the longitudinal direction. In different embodiments, the body  16  may have different cross-sectional profiles taken near a midpoint of the lengthwise dimension. For example, in  FIG. 6   a  the body  16  may have a cross-sectional profile of a rectangle or square. In  FIG. 6   b , the body  16  may have a cross-sectional profile of a square portion  32  and a necked-down portion  34  extending from the square portion. In  FIG. 6   c , the body  16  may taper in width from an upper wall  36  to a lower wall  38 . And in  FIG. 6   d , the body  16  may be generally I-shaped in cross-sectional profile. Other cross-sectional profiles are possible. 
     The body  16  may have a first and second side wall  40 ,  42 . A first and second hole  44 ,  46  may be located in the respective first and second side walls  40 ,  42 . The first and second holes  44 ,  46  may be aligned with each other and may be constructed to receive a dowel pin (not shown) transversely through the body  16  and through the internal channel  30  upon assembly. In use, the body  16  may pivot at the dowel pin. Referring to  FIG. 9 , a first flange  48  and a second flange  50  may extend in an inwardly or outwardly direction from the respective first and second hole  44 ,  46 . The first and second flanges  48 ,  50  may be formed in a metalworking process after the hydroforming process such as a dish or draw-forming process. The first and second flanges  48 ,  50  may increase the surface area of contact between the first and second holes  44 ,  46  and the dowel pin. 
     Referring to  FIGS. 2-5 , the body  16  may have a working pad or portion  52  located on the lower wall  38 . In use, the working portion  52  may be acted upon and directly contacted by the plunger  20 . The working portion  52  may be formed as part of the hydroforming process; that is, the shape of the working portion  52  may be designed into the die halves of the hydroforming machine. In  FIG. 3 , the working portion  52  may have a convex or bulged shape, and in  FIG. 5 , the working portion may have a concave or indented shape. Other shapes are possible and may depend on, among other things, the shape of a portion of the plunger  20  that contacts the working portion  52 . 
     Referring to  FIG. 8 , the body  16  may have a first, second, and third opening  54 ,  56 , and  58  located in the upper wall  36 . The first, second, and third openings  54 ,  56 , and  58  may receive parts of the sliding piece  18  to form a mechanical interconnection therebetween upon assembly, as will be subsequently described. The openings may have different shapes, sizes, and locations. In the illustrated embodiment, the first opening  54  may be generally rectangular and may be spaced away from the second opening  56  with a bridge  60  therebetween. The second and third openings  56 ,  58  may also be generally rectangular or square. 
     In the illustrated embodiment of  FIGS. 1-9 , the sliding piece  18  may bear directly against the chain  22  during use, and may provide a low friction sliding surface for the chain. In some cases, the sliding piece  18  need not be provided such as when a low friction chain  22  is used; here, the chain would bear directly against the upper wall  36  of the body  16 . The sliding piece  18  may be made of nylon or another suitable material, and may be made by an injection molding process or another suitable process. The sliding piece  18  may be a separate component than the body  16 , and may be mechanically interconnected to the body. Referring to  FIGS. 7-9 , the sliding piece  18  may have a first, second, and third protrusion or finger  62 ,  64 , and  66  that may extend downward from a lower surface  68 , and then may extend longitudinally therefrom. Upon assembly, the first finger  62  may be inserted into the first open free end  26  and into the internal channel  30 . The first finger  62  may wrap around the upper wall  36  and may form a clearance-fit therewith. The second finger  64  may be first inserted into the first opening  54 , and then may slide over the bridge  60  and snap into the second opening  56 . And the third finger  66  may be inserted into the third opening  58 . When interconnected, the sliding piece  18  may be prevented from moving in a direction A of chain movement. In other embodiments, other mechanical interconnecting structures are possible; for example, one or more openings or recesses may be located in the sliding piece and one or more complementary projections may extend from the body, or one or more openings or recesses may be located on the side walls of the body and one or more complementary projections may extend from sides of the sliding piece to be inserted therein. 
     The sliding piece  18  may also have a first, second, and third rim  70 ,  72 , and  74  that may extend downward from the lower surface  68  and along edges of the sliding piece. The rims  70 ,  72 ,  74  may help locate the lateral position of the sliding piece  18  onto the body  16 , and may provide support for positioning the sliding piece onto the body. On an upper surface  76 , the sliding piece  18  may have a first and second flange  78 ,  80  extending upward from the upper surface at a respective edge thereof. The flanges  78 ,  80  may help locate the lateral position of the chain  22  as the chain traverses the upper surface  76 . 
     In the illustrated embodiment of  FIG. 10 , the chain guide  12  may have some similarities with the tensioner arm  10  that will not be repeated in detail here. For instance, the chain guide  12  may have a body  116  that may be made by a hydroforming process to have a hollow shape and structure. The body  116  may be elongated in its longitudinal (lengthwise) direction and may extend from a first open free end  126  to a second open free end  128 . The body  118  may have an internal channel  130  which may have the different cross-sectional profiles of  FIGS. 6   a - 6   d . The body  116  may have one or more hole(s)  145  for receiving a bolt to attach the body to the internal combustion engine or a structure thereof. The body  116  may also have a first, second, and third opening  154 ,  156 , and  158  for a mechanical interconnection with a sliding piece  118 . The sliding piece  118  may have a first, second, and third protrusion or finger  162 ,  164 , and  166  that interact with the first open end  126  and first, second, and third openings  154 ,  156 , and  158  as previously described. 
     The chain guide  12  may have some differences with the tensioner arm  10 . For instance, the body  116  may not have a working pad or portion because the body is not acted upon by a plunger and does not pivot like the tensioner arm  10 , and instead remains stationary for guiding the chain  22 . The sliding piece  118  may have a triangular head  182  extending from an end of the sliding piece  118 . The head  182  may be used to help prevent a tooth of the chain  22  from jumping on an associated sprocket tooth. 
     The bodies and sliding pieces of the tensioner arm  10  and chain guide  12  shown and described are only exemplary. Their shape, construction, configuration, and/or arrangement may vary with different applications, timing chain systems, and internal combustion engines. 
     The following describes various embodiments that are within the scope of the invention but the invention is not limited thereto. Embodiment 1 includes a product comprising: an automotive timing chain system component ( 10 ,  12 ) constructed to bear against a chain ( 22 ) of an automotive timing chain system ( 14 ), the component ( 10 ,  12 ) having an elongated body ( 16 ,  116 ) made into a generally hollow shape by a hydroforming process, the body ( 16 ,  116 ) having a first open free end ( 26 ,  126 ), a second open free end ( 28 ,  128 ), and an upper wall ( 36 ) extending along the length of the body ( 16 ,  116 ) from the first open free end ( 26 ,  126 ) to the second open free end ( 28 ,  128 ). 
     Embodiment 2 includes a product as set forth in embodiment 1 wherein the automotive timing chain system component ( 10 ,  12 ) is a tensioner arm ( 10 ). 
     Embodiment 3 includes a product as set forth in any one of embodiments 1 to 2 wherein the automotive timing chain system component ( 10 ,  12 ) is a chain guide ( 12 ). 
     Embodiment 4 includes a product as set forth in any one of embodiments 1-3 wherein the component ( 10 ,  12 ) comprises a sliding piece ( 18 ,  118 ) constructed to bear directly against the chain ( 22 ) and being mechanically interconnected to the upper wall ( 36 ) of the body ( 16 ,  116 ). 
     Embodiment 5 includes a product as set forth in any one of embodiments 1-4 wherein the body ( 16 ,  116 ) has at least one opening ( 54 ,  56 ,  58 ,  154 ,  156 ,  158 ) located in the upper wall ( 36 ), and the sliding piece ( 18 ,  118 ) has at least one finger ( 62 ,  64 ,  66 ,  162 ,  164 ,  166 ) inserted into the at least one opening ( 54 ,  56 ,  58 ,  154 ,  156 ,  158 ) upon mechanical interconnection of the body ( 16 ,  116 ) and the sliding piece ( 18 ,  118 ). 
     Embodiment 6 includes a product as set forth in any one of embodiments 1-5 wherein the at least one opening ( 54 ,  56 ,  58 ,  154 ,  156 ,  158 ) comprises a first, second, and third opening ( 54 ,  56 ,  58 ,  154 ,  156 ,  158 ), the at least one finger ( 62 ,  64 ,  66 ,  162 ,  164 ,  166 ) comprises a first, second, and third finger ( 62 ,  64 ,  66 ,  162 ,  164 ,  166 ), and, upon mechanical interconnection, the first finger ( 62 ,  162 ) is inserted into the first open free end ( 26 ,  126 ), the second finger ( 64 ,  164 ) is inserted into the first and second openings ( 54 ,  56 ,  154 ,  156 ), and the third finger ( 66 ,  166 ) is inserted into the third opening ( 58 ,  158 ). 
     Embodiment 7 includes a product as set forth in any one of embodiments 1-6 wherein the body ( 16 ,  116 ) has a cross-sectional profile taken at about a midpoint of its lengthwise dimension of a generally square portion ( 32 ) and a generally necked-down portion ( 34 ) extending from the square portion ( 32 ). 
     Embodiment 8 includes a product as set forth in any one of embodiments 1-7 wherein the body ( 16 ,  116 ) has a cross-sectional profile taken at about a midpoint of its lengthwise dimension of a rectangle. 
     Embodiment 9 includes a product as set forth in any one of embodiments 1-8 wherein the body ( 16 ,  116 ) has a cross-sectional profile taken at about a midpoint of its lengthwise dimension that tapers from the upper wall ( 36 ) to a lower wall ( 38 ), the upper wall ( 36 ) being wider than the lower wall ( 38 ). 
     Embodiment 10 includes a product as set forth in any one of embodiments 1-9 wherein the body ( 16 ,  116 ) has a cross-sectional profile taken at about a midpoint of its lengthwise dimension of a generally I-shape. 
     Embodiment 11 includes a product as set forth in any one of embodiments 1-10 wherein the body ( 16 ,  116 ) has at least a first and second hole ( 44 ,  46 ) located in a respective first and second side wall ( 40 ,  42 ) of the body ( 16 ,  116 ) for receiving a dowel pin transversely through the body ( 16 ,  116 ), the first and second holes ( 44 ,  46 ) having a respective first and second flange ( 48 ,  50 ) extending from the respective first and second side walls ( 40 ,  42 ). 
     Embodiment 12 includes a product comprising: a tensioner arm ( 10 ) for an automotive timing chain system ( 14 ), the tensioner arm ( 10 ) including a body ( 16 ) made into a generally hollow shape by a hydroforming process, and including a sliding piece ( 18 ) mechanically interconnected to the body ( 16 ) and constructed to bear directly against a chain ( 22 ) of the automotive timing chain system ( 14 ). 
     Embodiment 13 includes a product as set forth in embodiment 12 wherein the body ( 16 ) extends in a lengthwise direction from a first open free end ( 26 ) to a second open free end ( 28 ), and the body ( 16 ) has an internal channel ( 30 ) extending from the first open free end ( 26 ) to the second open free end ( 28 ). 
     Embodiment 14 includes a product as set forth in any one of embodiments 12-13 wherein the body ( 16 ) has a convex working portion ( 52 ) acted upon by a plunger ( 20 ) of the automotive timing chain system ( 14 ) and formed as part of the hydroforming process. 
     Embodiment 15 includes a product as set forth in any one of embodiments 12-14 wherein the body ( 16 ) has a concave working portion ( 52 ) acted upon by a plunger ( 20 ) of the automotive timing chain system ( 14 ) and formed as part of the hydroforming process. 
     Embodiment 16 includes a method comprising: hydroforming a body ( 16 ,  116 ) of an automotive timing chain system component ( 10 ,  12 ) into a generally hollow and elongated shape, the body ( 16 ,  116 ) having an upper wall ( 36 ) extending along the length of the body ( 16 ,  116 ) and having at least one opening ( 54 ,  56 ,  58 ,  154 ,  156 ,  158 ) located in the upper wall ( 36 ); forming a sliding piece ( 18 ,  118 ) for bearing against a chain ( 22 ) of an automotive timing chain system ( 14 ), the sliding piece ( 18 ,  118 ) having at least one finger ( 62 ,  64 ,  66 ,  162 ,  164 ,  166 ); and connecting the body ( 16 ,  116 ) and the sliding piece ( 18 ,  118 ) by inserting the at least one finger ( 62 ,  64 ,  66 ,  162 ,  164 ,  166 ) into the at least one opening ( 54 ,  56 ,  58 ,  154 ,  156 ,  158 ). 
     Embodiment 17 includes a method as set forth in embodiment 16 wherein the automotive timing chain system component ( 10 ,  12 ) is a tensioner arm ( 10 ), and hydroforming comprises hydroforming a convex working portion ( 52 ) acted upon by a plunger ( 20 ) of the automotive timing chain system ( 14 ) into the body ( 16 ). 
     Embodiment 18 includes a method as set forth in any one of embodiments 16-17 wherein the automotive timing chain system component ( 10 ,  12 ) is a tensioner arm ( 10 ), and hydroforming comprises hydroforming a concave working portion ( 52 ) acted upon by a plunger ( 20 ) of the automotive timing chain system ( 14 ) into the body ( 16 ). 
     The above description of embodiments of the invention is merely exemplary in nature and, thus, variations thereof are not to be regarded as a departure from the spirit and scope of the invention.