Patent Publication Number: US-9903234-B2

Title: Retention plate

Description:
TECHNICAL FIELD 
     The present disclosure relates to a retention plate. More particularly, the present disclosure relates to the retention plate for a valve train of an engine. 
     BACKGROUND 
     Generally, a valve train of an engine employs a pushrod and a hydraulic lash adjuster to transmit motion from a rotary cam to a rocker arm of the valve train. Due to continuous operation, the pushrod may experience loosening or breakage. In such a situation, the pushrod may move from its position and may slip into a cavity of the engine such as within the engine block. As a result, the slipped pushrod may interfere with other parts within the engine causing extreme damage to the engine. For example, the pushrod may slip back into the engine block and damage one or more valves associated with a cooling/lubrication system of the engine. This may lead to coolant/lubrication leakage or contamination, resulting in machine downtime, expensive repairs, and so on. 
     U.S. Pat. No. 6,978,752 describes a valve lifter guide for use with an internal combustion engine. The valve lifter guide is adapted for maintaining an angular position of a reciprocable valve lifter. The valve lifter includes a circumferential surface with an axially extending alignment flat. The valve lifter guide includes a metal guide body having a longitudinal guide wall. The guide wall includes a guide opening adapted to receive a valve lifter. The valve lifter guide includes a nonmetallic insert extending laterally across the guide wall. The insert is retained by the guide body adjacent a longitudinal end of the guide opening. The insert is positioned to engage the alignment flat of the valve lifter received in the guide opening to substantially maintain the angular position of the valve lifter in the guide. 
     Currently used guides for the valve train may be unable to restrict slippage of the pushrod within the cavity of the engine in case of a failure thereof. Hence, there is a need for an improved system for controlling slippage of the pushrod into the engine. 
     SUMMARY OF THE DISCLOSURE 
     In an aspect of the present disclosure, a retention plate for a hydraulic lash adjuster of a valve train is provided. The retention plate includes a first surface. The retention plate includes a second surface mutually opposite the first surface. The second surface is adapted to contact with a cylinder head of an engine. The retention plate also includes a coupling mechanism defined on the retention plate. The coupling mechanism is adapted to couple the retention plate to the cylinder head. The coupling mechanism includes a through hole adapted to receive a mechanical fastener therethrough. The retention plate further includes a restriction mechanism defined on the retention plate. The restriction mechanism is adapted to restrict a movement of the hydraulic lash adjuster beyond the first surface towards the cylinder head. The restriction mechanism includes an aperture having an aperture size smaller than an outer diameter of the hydraulic lash adjuster. 
     In another aspect of the present disclosure, a valve train is provided. The valve train includes a valve. The valve train includes a valve spring coupled to the valve. The valve train includes a rocker arm having a first end and a second end. The first end of the rocker arm is coupled to the valve. The valve train includes a rocker stand pivotally coupled to the rocker arm. The valve train includes an adjustment screw coupled to the second end of the rocker arm. The valve train includes a hydraulic lash adjuster having a first end and a second end. The first end of the hydraulic lash adjuster is coupled to the adjustment screw. The valve train also includes a pushrod coupled to the second end of the hydraulic lash adjuster. The valve train further includes a retention plate. The retention plate includes a first surface. The retention plate includes a second surface mutually opposite the first surface. The second surface is adapted to contact with a cylinder head of an engine. The retention plate also includes a coupling mechanism defined on the retention plate. The coupling mechanism is adapted to couple the retention plate to the cylinder head. The coupling mechanism includes a through hole adapted to receive a mechanical fastener therethrough. The retention plate further includes a restriction mechanism defined on the retention plate. The restriction mechanism is adapted to restrict a movement of the hydraulic lash adjuster beyond the first surface towards the cylinder head. The restriction mechanism includes an aperture having an aperture size smaller than an outer diameter of the hydraulic lash adjuster. 
     In yet another aspect of the present disclosure, an engine system is provided. The engine system includes an engine block. The engine system includes a cylinder head. The engine system also includes a valve train having a hydraulic lash adjuster. The engine system further includes a retention plate for the hydraulic lash adjuster. The retention plate includes a first surface. The retention plate includes a second surface mutually opposite the first surface. The second surface is adapted to contact with the cylinder head. The retention plate also includes a coupling mechanism defined on the retention plate. The retention plate is coupled to the cylinder head through the coupling mechanism. The retention plate further includes a restriction mechanism defined on the retention plate. The restriction mechanism is adapted to restrict a movement of the hydraulic lash adjuster beyond the first surface towards the cylinder head. The restriction mechanism includes an aperture having an aperture size smaller than an outer diameter of the hydraulic lash adjuster. 
     Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary engine system, according to one embodiment of the present disclosure; 
         FIG. 2  is a partial perspective view of a valve train of the engine system of  FIG. 1  with a retention plate, according to one embodiment of the present disclosure; 
         FIG. 3  is a perspective view of the retention plate of  FIG. 2 , according to one embodiment of the present disclosure; 
         FIG. 4  is a perspective view of the retention plate of  FIG. 3  and a fixture, according to one embodiment of the present disclosure; and 
         FIG. 5  is a partial perspective view of the valve train of the engine system of  FIG. 1  with a retention plate, according to another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. Referring to  FIG. 1 , an exemplary engine system  100  is illustrated. The engine system  100  includes an internal combustion engine  102  powered by any fuel known in the art such as gasoline, diesel, natural gas, and so on, or a combination thereof. The engine system  100  may be used for applications including, but not limited to, power generation, transportation, construction, agriculture, forestry, aviation, marine, material handling, and waste management. 
     The engine system  100  includes an engine block  104 . The engine block  104  includes one or more cylinders (not shown) provided therein. The cylinders may be arranged in any configuration such as inline, radial, “V”, and so on. The engine system  100  also includes a cylinder head  106  mounted on the engine block  104 . The cylinder head  106  is adapted to house one or more components and/or systems (not shown) of the engine system  100  such as a valve train, an intake manifold, an exhaust manifold, sensors, and so on. Additionally, the engine system  100  may include various other components and/or systems (not shown) such as a crankcase, a fuel system, an air system, a cooling system, a turbocharger, an exhaust gas recirculation system, an exhaust aftertreatment system, other peripheries, and so on. 
     Referring to  FIG. 2 , the engine system  100  includes a valve train  200 . The valve train  200  includes a valve (not shown). The valve is provided is association with an inlet port (not shown) or an outlet port (not shown) of the cylinder head  106 . The valve is adapted to selectively open or close the inlet port or the outlet port during operation of the engine system  100 . The valve train  200  includes a valve spring (not shown) coupled to the valve. The valve spring is adapted to bias the valve in an open position or a closed position based on application requirements. 
     The valve train  200  includes a rocker arm  202 . The rocker arm  202  has a first end (not shown) and a second end  206 . The first end of the rocker arm  202  is coupled to the valve through a valve bridge (not shown). The valve train  200  includes a rocker stand  208  provided on a surface  210  of the cylinder head  106 . The rocker stand  208  is pivotally coupled to the rocker arm  202 . The rocker stand  208  is adapted to support the rocker arm  202  and provide an oscillatory motion to the rocker arm  202 . The valve train  200  includes an adjustment screw  212 . The adjustment screw  212  is coupled to the second end  206  of the rocker arm  202 . The adjustment screw  212  is adapted to adjust a valve clearance based on application requirements. 
     The valve train  200  also includes a pushrod  214 . The pushrod  214  has a first end (not shown) and a second end  216 . The first end of the pushrod  214  is operably coupled to a cam (not shown) of the engine system  100 . More specifically, the pushrod  214  is received through a slot  218  in the cylinder head  106  for operably coupling the first end of the pushrod  214  with the cam. Accordingly, a size of the slot  218  is larger than an outer diameter of the pushrod  214 . Based on a rotation of the cam, the pushrod  214  is adapted to translate in a direction substantially perpendicular to the surface  210  of the cylinder head  106 . In the illustrated embodiment, the pushrod  214  is adapted to translate in a vertical direction. In a horizontally oriented engine system  100 , the pushrod  214  may be adapted to translate in a horizontal direction based on the rotation of the cam. The second end  216  of the pushrod  214  is coupled to a Hydraulic Lash Adjuster (HLA)  220 . 
     The valve train  200  includes the HLA  220  having a first end  222  and a second end  224 . The first end  222  of the HLA  220  is coupled to the adjustment screw  212 . In some embodiments, the adjustment screw  212  may be omitted. In such a situation, the first end  222  of the HLA  220  may be coupled to the second end  206  of the rocker arm  202 . The second end  224  of the HLA  220  is coupled to the second end  216  of the pushrod  214 . The HLA  220  is adapted to maintain a required valve clearance such as a zero valve clearance based on application requirements. The HLA  220  is also adapted to compensate for thermal expansion and reduce wear and tear of components of the valve train  200 . The HLA  220  may be any lash adjuster known in the art such as a piston cylinder based lash adjuster, a spring based lash adjuster, and so on. The HLA  220  has an outer diameter larger than the outer diameter of the pushrod  214 . 
     The present disclosure relates to a retention plate  226  provided in association with the valve train  200 . The retention plate  226  is provided on the surface  210  of the cylinder head  106  and adjacent to the slot  218  of the cylinder head  106 . The retention plate  226  may be made of any metal known in the art such as, for example, steel. The retention plate  226  may be made by any known manufacturing process such as forging, casting, joining, and so on. 
     Referring to  FIG. 3 , the retention plate  226  has a flat, planar, and substantially oval configuration. The retention plate  226  has a first surface  302 . The retention plate  226  also has a second surface  304 . The second surface  304  is mutually opposite the first surface  302 . Further, the first surface  302  and the second surface  304  are spaced apart from one another defining a thickness “T” of the retention plate  226 . The second surface  304  is adapted to contact with the surface  210  of the cylinder head  106  (see  FIG. 2 ). 
     The retention plate  226  includes a coupling mechanism defined thereon. The coupling mechanism is adapted to couple the retention plate  226  to the cylinder head  106 . More specifically, the coupling mechanism includes a through hole  308 . The through hole  308  is adapted to receive a mechanical fastener  408  (see  FIG. 4 ) therethrough. In the illustrated embodiment, the mechanical fastener  408  is a head bolt adapted to couple the cylinder head  106  with the engine block  104 . In other embodiments, the mechanical fastener  408  may be any other bolt different from the head bolt, a screw, a rivet, and so on adapted to couple the retention plate  226  to the cylinder head  106 . In yet other embodiments, the retention plate  226  may be coupled to the cylinder head  106  by any joining process such as welding, brazing, and so on. It should be noted that number, location, dimension and configuration of the through hole  308  disclosed herein is merely exemplary and does not limit the scope of the disclosure. 
     The retention plate  226  also includes a restriction mechanism defined thereon. The restriction mechanism is adapted to restrict a movement of the HLA  220  beyond the first surface  302  of the retention plate  226  towards the cylinder head  106 . The restriction mechanism includes an aperture  314 . The aperture  314  is adapted to receive the pushrod  214  therethrough. Accordingly, an aperture size of the aperture  314  is larger than the outer diameter of the pushrod  214 . The aperture  314  is shaped to conform to the outer diameter of the pushrod  214 . 
     Further, the aperture size of the aperture  314  is smaller than the outer diameter of the HLA  220  in order to restrict the movement of the HLA  220  beyond the first surface  302  of the retention plate  226  towards the cylinder head  106 . More specifically, during operation of the engine system  100 , when the pushrod  214  and in turn the HLA  220  may move toward the cylinder head  106 , the second end  224  of the HLA  220  may contact the first surface  302  of the retention plate  226 . Since the aperture size of the aperture  314  is smaller than the outer diameter of the HLA  220 , the first surface  302  of the retention plate  226  may present itself as an obstruction preventing the HLA  220  from moving towards or into the cylinder head  106 . As a result, the movement of the HLA  220  and in turn the pushrod  214  is restricted beyond the first surface  302  of the retention plate  226 . 
     Also, the thickness “T” of the retention plate  226  is selected in a manner such that the thickness “T” is lesser than a distance between the surface  210  of the cylinder head  106  and the second end  224  of the HLA  220 . As a result, during normal operation of the valve train  200  and the translatory motion of the HLA  220 , the second end  224  of the HLA  220  may not contact with the first surface  302  of the retention plate  226 . More specifically, the second end  224  of the HLA  220  may contact the first surface  302  of the retention plate  226  and may be restricted thereby only when the HLA  220  may move toward the cylinder head  106  due to excessive movement in the system. 
     In the illustrated embodiment, the restriction mechanism includes a first aperture  316  and a second aperture  318 . In other embodiments, the restriction mechanism may include a single aperture or multiple apertures based on application requirements. Each of the first aperture  316  and the second aperture  318  is adapted to receive a separate pushrod  214  of the valve train  200  of the engine system  100 . The first aperture  316  is positioned adjacent to the second aperture  318 . Also, the first aperture  316  and the second aperture  318  are equidistant from the through hole  308 . It should be noted that number, location, dimension and configuration of the aperture  314 , the first aperture  316  and/or the second aperture  318  disclosed herein is merely exemplary and may not limit the scope of the disclosure. 
     Additionally, the retention plate  226  includes a fixation mechanism. The fixation mechanism includes a pair of openings  322 . Each of the pair of openings  322  is positioned on either sides of the through hole  308 . Also, a diameter of the through hole  308  is at least twice a diameter of each of the pair of openings  322 . Each of the pair of openings  322  is adapted to receive a mechanical fastener therein such as a secondary pin  406  (see  FIG. 4 ) of a fixture  402  (see  FIG. 4 ). More specifically, during assembly of the retention plate  226 , the fixture  402  is provided to align and hold the retention plate  226  in place. It should be noted that number, location, dimension and configuration of the openings  322  disclosed herein is merely exemplary and may not limit the scope of the disclosure. 
     Referring to  FIG. 4 , the fixture  402  includes one or more primary pins  404 . Each of the primary pins  404  is adapted to be received into an alignment hole (not shown) provided on the surface  210  of the cylinder head  106 . The alignment holes and the primary pins  404  are adapted to align the fixture  402  on the surface  210  of the cylinder head  106  with respect to the slot  218  of the cylinder head  106 . The fixture  402  also includes one or more secondary pins  406 . Each of the secondary pins  406  is adapted to be received into each of the pair of openings  322  of the fixation mechanism provided on the retention plate  226 . 
     The secondary pins  406  are adapted to align the retention plate  226  with respect to the fixture  402  and the slot  218 . More specifically, the retention plate  226  is aligned such that the first aperture  316  and the second aperture  318  are coaxially aligned with respect to the slot  218  of the cylinder head  106 . The secondary pins  406  are also adapted to hold the retention plate  226  in place during assembly. 
     During assembly of the retention plate  226 , the fixture  402  is provided on the cylinder head  106  to correctly align the retention plate  226  with respect to the slot  218  of the cylinder head  106 . The primary pins  404  of the fixture  402  are then received in the alignment holes of the cylinder head  106 . As a result, the fixture  402  may then by aligned with respect to the cylinder head  106 . Further, the secondary pins  406  are received into the pair of openings  322  provided on the retention plate  226 . As a result, the retention plate  226  may be aligned with respect to the fixture  402  and the slot  218  of the cylinder head  106 . More specifically, the first aperture  316  and the second aperture  318  are coaxially aligned with respect to the slot  218  of the cylinder head  106 . The mechanical fastener  408  is then provided in the through hole  308  and torqued to couple the retention plate  226  with the cylinder head  106 . During the torquing, the fixture  402  holds the retention plate  226  in place and restricts movement of the retention plate  226 . Once assembled, the fixture  402  is released from the cylinder head  106 . 
     Referring to  FIG. 5 , another embodiment of a retention plate  502  is illustrated. The retention plate  502  includes one or more cutouts  504 . The retention plate  502  is provided on the surface  210  of the cylinder head  106  in a manner such that the cutouts  504  align with the slot  218  of the cylinder head  106 . The cutouts  504  are adapted to receive the pushrod  214  therethrough. Accordingly, a size of the cutouts  504  is larger than the outer diameter of the pushrod  214 . Also, the size of the cutouts  504  is smaller than the outer diameter of the HLA  220 . During the movement of the HLA  220  toward the cylinder head  106 , the second end  224  of the HLA  220  may contact the first surface  506  of the retention plate  502  and restrict further movement of the HLA  220  and the pushrod  214  toward the cylinder head  106 . The retention plate  502  also includes one or more arms  508 . In the illustrated embodiment, the arms  508  are adapted to couple the retention plate  502  with the rocker stand  208 . In other embodiments, the arms  508  may be adapted to couple the retention plate  502  with the cylinder head  106  or any other component of the engine system  100  based on application requirements. 
     INDUSTRIAL APPLICABILITY 
     The present disclosure relates to the retention plate  226 ,  502  adapted to restrict the movement of the HLA  220  beyond the first surface  302  of the retention plate  226 ,  502 . In situations such as a loosened or broken pushrod  214 , the design of the retention plate  226 ,  502  is such that the second end  224  of the HLA  220  may contact with the first surface  302  of the retention plate  226 ,  502 , thereby restricting the HLA  220  from further moving into the slot  218  and the engine block  104 . Further, during complete detachment of the pushrod  214  from the cam and/or the HLA  220  from the adjustment screw  212  or the second end  206  of the rocker arm  202 , the pushrod  214  and the HLA  220  may move towards the cylinder head  106 . As a result, the second end  224  of the HLA  220  may contact and rest on the first surface  302  of the retention plate  226 ,  502 . This may restrict further slipping of the pushrod  214  and the HLA  220  within the engine block  104  and the HLA  220  may be retained above the cylinder head  106 . 
     In situations when the head bolt is used to couple the retention plate  226 , 502  to the cylinder head  106 , the retention plate  226 ,  502  additionally serves as a washer for the head bolt eliminating a need for a separate washer. Due to a configuration of the retention plate  226 ,  502 , the retention plate  226 ,  502  may be coupled to the cylinder head  106  without any major modifications to the existing valve train  200  and/or the cylinder head  106 . 
     While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of the disclosure. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.