Abstract:
Tools and methods for indenting and assembling a switching rocker arm assembly having an inner arm, an outer arm and a latch. The tools and methods are directed to eliminating requirements for matched sets of components of rocker arm assemblies so that the assembled indented parts have desired latch lash tolerances. The tools used include fixtures and clamps for indenting kidney-bean shaped passages in an outer arm that mount a pivot axle of the outer arm. The tools used may also include a fixture and clamps for indenting a latch shelf of the inner arm. Indenting the inner arm and outer arm using these methods and fixtures results in switching rocker arm assemblies that fit together, and when assembled into a valve, have a desired latch lash.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 14/838,749 (EATN-0215-U01), filed Aug. 28, 2015, and entitled VALVE ACTUATING DEVICE AND METHOD OF MAKING SAME.” U.S. patent application Ser. No. 14/838,749 (EATN-0215-U01) is a continuation of International Appl. No. PCT/US2015/018445 (EATN-0215-WO) filed Mar. 3, 2015, of the same title. 
         [0002]    International Application No. PCT/US2015/018445 (EATN-0215-WO) claims the benefit of International Application No. PCT/US2014/019870 (EATN-0213-WO) filed on Mar. 3, 2014; U.S. patent application Ser. No. 61/986,976 (EATN-0215-P01) filed on May 1, 2014; and U.S. patent application Ser. No. 62/081,306 (EATN-0215-P02) filed on Nov. 18, 2014. Each of the above applications is incorporated herein by reference in its entirety. 
     
    
     FIELD 
       [0003]    The present disclosure relates generally to switching roller finger followers or rocker arms in internal combustion engines and more particularly to a method of making or assembling an inner arm, an outer arm and a latch of the switching rocker arm. 
       BACKGROUND 
       [0004]    A switching roller finger follower or rocker arm allows for control of valve actuation by alternating between two or more states. In some examples, the rocker arm can include multiple arms, such as an inner arm and an outer arm. In some circumstances, these arms can engage different cam lobes, such as low-lift lobes, high-lift lobes, and no-lift lobes. Mechanisms are required for switching rocker arm modes in a manner suited for operation of internal combustion engines. 
         [0005]    Typically the components of the rocker arm are sized and sorted before assembly such that the appropriate combination of components is selected in an effort to satisfy latch lash tolerances. The sizing and sorting process can be time consuming. It would be desirable to simplify the assembly process and provide better latch lash control. 
         [0006]    The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. 
       SUMMARY 
       [0007]    A method of assembling a switching rocker arm assembly having an inner arm, an outer arm and a latch is provided. The method includes, indenting an outer arm surface on the outer arm, the outer arm surface defining an arcuate aperture. An inner arm surface can be indented on the inner arm at an inner arm latch shelf. A latch can be positioned relative to the inner and outer arms. 
         [0008]    According to additional features, the inner and outer arms can be located into a fixture base. A press ram can be actuated onto a first indenting tool that acts against the outer arm surface. The outer arm can be collectively defined by a first outer arm and a second outer arm. Indenting the outer arm surface on the outer arm can further include, locating the first indenting tool through the arcuate passage. The arcuate aperture can be collectively defined by a first outer arm surface provided by the first outer arm and a second outer arm surface provided by the second outer arm. The first and second outer arm surfaces can be deflected with the first indenting tool. A pivot swivel can be positioned against a pivot axle that pivotally couples the inner arm and the outer arm. Misalignments of outer arm reaction surfaces can be compensated for with the fixture base. The indenting of the outer arm surface can be continued until a pin is permitted to slidably advance adjacent to the latch shelf. Actuating the press ram onto the first indenting tool can include transferring a force from the press ram onto a tungsten tool. 
         [0009]    According to additional features, indenting the inner arm surface can further include positioning a second indenting tool through an outer arm latch bore and adjacent to the inner arm latch shelf. An indention load can be transferred onto the inner arm, through the second indenting tool and onto the inner arm latch shelf. Positioning the second indenting tool can comprise, positioning a tungsten pin through the outer arm latch bore and adjacent to the inner arm latch shelf. The indenting of the inner arm surface can be continued until a transformer provides a stop signal. 
         [0010]    A method of assembling a switching rocker arm assembly according to additional features of the present disclosure is provided. The switching rocker arm assembly can have an inner arm, an outer arm and a latch. The switching rocker arm assembly can be configured to operate in a first normal-lift position where the inner and outer arms are locked together and a second no-lift position where the inner and outer arms move independently. The method can include, indenting an outer arm surface on the outer arm. The outer arm surface can define an arcuate aperture. An inner arm latch surface can be indented on the inner arm. The inner arm latch surface can correspond to a surface that the latch engages during the normal-lift position. A latch can be positioned relative to the inner and outer arms. 
         [0011]    According to additional features, the outer arm can be collectively defined by a first outer arm and a second outer arm. Indenting the outer arm surface on the outer arm can further include, locating a first indenting tool through the arcuate aperture. The arcuate aperture can be defined by a first outer arm surface provided on the first outer arm and a second outer arm surface provided by the second outer arm. The first and second outer arm surfaces can be deflected with the first indenting tool. According to additional features, a pivot swivel can be positioned against a pivot axle that pivotally couples the inner arm and the outer arm. Misalignments of outer arm reaction forces can be compensated for with the fixture base. The indenting of the outer arm surface can be continued until a pin is permitted to slidably advance adjacent to the inner arm latch surface. A press ram can be actuated onto the first indenting tool. A force from the press ram can be transferred onto the indenting tool. Indenting the inner arm surface can further comprise, positioning a second indenting tool through an outer arm latch bore and adjacent to the inner arm latch surface. An indention load can be transferred onto the inner arm, through the second indenting tool and onto the inner arm latch surface. Positioning the second indenting tool can comprise positioning a tungsten pin through the outer arm latch bore and adjacent to the inner arm latch surface. The indenting of the inner arm latch surface can continue until a transformer provides a stop signal. 
         [0012]    A method of assembling a switching rocker arm assembly according to other features is provided. The switching rocker arm assembly can have an inner arm, an outer arm and a latch. The outer arm can have an arcuate aperture collectively defined by a first outer arm surface on a first outer arm and a second outer arm surface on a second outer arm. The inner arm can have an inner arm latch surface. The switching rocker arm assembly can be configured to operate in a first normal-lift position where the inner and outer arms are locked together and a second no-lift position where the inner and outer arms move independently. The method can include, locating a first indenting tool through the arcuate passage. The first and second outer arm surfaces can be indented on the outer arm with the first indenting tool. A second indenting tool can be located adjacent to the inner arm latch surface. The inner arm latch surface on the inner arm can be indented. The inner arm latch surface can correspond to a surface that the latch engages during the normal-lift position. A latch can be positioned relative to the inner and outer arms. 
         [0013]    According to additional features, the inner and outer arms can be located into a fixture base. A press ram can be actuated onto the first indenting tool that acts against the outer arm surface. A pivot swivel can be positioned against a pivot axle that pivotally couples the inner arm and the outer arm. Misalignments of outer arm reaction surfaces can be compensated for with the fixture base. The indenting of the outer arm surface can be continued until a pin is permitted to slidably advance adjacent to the inner arm latch surface. The indenting of the inner arm latch surface can further include, positioning the second indenting tool through an outer arm latch bore and adjacent to the inner arm latch surface. An indention load can be transferred onto the inner arm, through the second indenting tool and onto the inner arm latch surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0015]      FIG. 1  is a front perspective view of an exemplary switching rocker arm constructed in accordance to one example of the present disclosure; 
           [0016]      FIG. 2  is an exploded perspective view of an exemplary outer arm, inner arm and latch pin during a size and sort process according to one prior art example; 
           [0017]      FIG. 3  is a side view of an exemplary kidney bean indention step according to the present disclosure; 
           [0018]      FIG. 4  is a side view of an exemplary latch indention step according to the present disclosure; 
           [0019]      FIG. 5  a perspective view of an exemplary kidney bean indention fixture assembly constructed in accordance to one example of the present disclosure; 
           [0020]      FIG. 6  is a cross-sectional view of the kidney bean indention fixture assembly of FIG. 
           [0021]      FIG. 7  is a perspective detail view of a tungsten axle indenting a surface that defines the kidney bean aperture; 
           [0022]      FIG. 8  is a perspective view of a latch indention fixture assembly constructed in accordance to one example of the present disclosure; 
           [0023]      FIG. 9  is a cross-sectional view of the latch indention fixture assembly of  FIG. 8 ; and 
           [0024]      FIG. 10  is perspective detail view of the inner arm contacting the fixture base of the latch indention fixture assembly of  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    With initial reference to  FIG. 1 , an exemplary switching rocker arm constructed in accordance to one example of the present disclosure is shown and generally identified at reference  10 . The switching rocker arm assembly  10  can be a compact cam-driven single-lobe cylinder deactivation (CDA-1L) switching rocker arm installed on a piston-driven internal combustion engine, and actuated with the combination of duel-feed hydraulic lash adjusters (DFHLA)  12  and oil control valves (OCV)  16 . The switching rocker arm assembly  10  can be engaged by a single lobe cam  20 . The switching rocker arm assembly  10  can include an inner arm  22 , and an outer arm  24 . The default configuration is in the normal-lift (latched) position where the inner arm  22  and the outer arm  24  are locked together, causing an engine valve  26  to open and allowing the cylinder to operate as it would in a standard valvetrain. The DFHLA  12  has two oil ports. A lower oil port  28  provides lash compensation and is fed engine oil similar to a standard HLA. An upper oil port  30 , referred to as the switching pressure port, provides the conduit between controlled oil pressure from the OCV  16  and a latch  32 . When the latch  32  is engaged, the inner arm  22  and the outer arm  24  operate together like a standard rocker arm to open the engine valve  26 . In the no-lift (unlatched) position, the inner arm  22  and the outer arm  24  can move independently to enable cylinder deactivation. 
         [0026]    A pair of lost motion torsion springs  40  is incorporated to bias the position of the inner arm  22  so that it always maintains continuous contact with the camshaft lobe  20 . The torsion springs  40  are secured to mounts located on the outer arm  24  by spring retainers  44 . The lost motion torsion springs  40  require a higher preload than designs that use multiple lobes to facilitate continuous contact between the camshaft lobe  20  and an inner arm roller bearing  50 . 
         [0027]    With reference now to  FIG. 2 , an exemplary flow chart  52  according to prior art is shown for determining the desired components to assemble together as a switching rocker arm assembly  10 . In general, each inner arm  22  and outer arm  24  is measured to determine specific tolerances. Once they are measured, they are sorted such as in bins, identified at block  54 . Similarly, each latch pin  32  is measured for tolerances and sorted accordingly. With the tolerances of each piece known, an inner arm  22 , outer arm  24  and latch pin  32  may be selected that collectively satisfy a predetermined tolerance. 
         [0028]    Turning now to  FIGS. 3 and 4 , the present teachings provide a two-step indention process for assembling the inner arm  22 , the outer arm  24  and latch pin  32 . In this regard, latch lash is set through the two step indention process. Step 1 ( FIG. 3 ) includes kidney bean indention. In general, the outer arm  24  defines an arcuate aperture or passage  60  in the shape of a kidney bean. The arcuate passage  60  is collectively defined by a first arcuate aperture or passage  60 A on a first outer arm  24 A and a second arcuate aperture or passage  60 B on a second outer arm  24 B (see  FIG. 2 ). The arcuate passage  60  similarly is provided with a kidney bean surface  66  collectively defined by a first kidney bean surface  66 A on the first outer arm  24 A and a second kidney bean surface  66 B on the second outer arm  24 B. In step 1, a force F 1  is applied such as on an indenting tool, axle or rod such as a tungsten tool  64  causing indention of the surface  66  defining the arcuate passage  60 . Reaction forces R 1  and R 2  can be provided at areas on the outer arm  24  as will become appreciated herein. The force F 1  is applied until the surface  66  reaches an optimum air gap. 
         [0029]    Step 2 ( FIG. 4 ) includes latch indention. A force F 2  is applied to the inner arm  22  to indent a latch surface  70  against a tungsten tool  74  assembled through a latch bore  80  (see FIS.  2  and  6 ) defined though the outer arm  24 . The latch surface  70  is the surface, also referred to herein as an “inner arm latch shelf”, that the latch pin  32  engages when the switching rocker arm assembly  10  is in the normal-lift (latched) position. A stop coining mandrel  82  can be located into the arcuate passage  60 . Reaction forces R 3  and R 4  can be provided at areas on the outer arm  24  as will become appreciated herein. The force F 2  is applied to the inner arm  22  until a final functional latch air gap is attained. Because the tolerances are controlled, a latch pin  32  ( FIG. 2 ) may then be assembled into the outer arm  24  without the need to sort. 
         [0030]    With reference now to  FIGS. 5-7 , exemplary components that may be used to carry out the kidney bean indention process of step 1 ( FIG. 3 ) will be described. In general, a kidney bean indention fixture assembly  100  can include a fixture base  104 , a pivot swivel  110 , a press ram  118 , a press swivel  120 , the tungsten tool or axle  64 , an E-foot clamp  124  and a linear variable displacement transformer (LVDT) sensor  128 . During use, the outer arm  24  may be positioned onto the fixture base  104 . Arms  140  extending from the press swivel  120  can engage the tungsten axle  64 . The pivot swivel  110  and E-foot clamp  124  can be positioned to support an end of the outer arm  24  and an end of the inner arm  22 . The press ram  118  can transfer a force through the press swivel  120  onto the tungsten axle  64  positioned in the kidney bean aperture  60  that ultimately causes an indentation onto the surface  66  of the kidney bean aperture  60  (see also  FIG. 3 ). Of note, the inner and outer arms  22  and  24  are both flipped to an inverted position in the kidney bean indention fixture assembly  100  as compared to the representation shown in  FIG. 3 . It will be appreciated that the inner and outer arms  22  and  24  may be positioned in any orientation during indentation of the surface  66  within the scope of the present teachings. The LVDT sensor  128  can measure variables such as load, vibration and displacement during the indention process. 
         [0031]    With continued reference to  FIGS. 5-7 , further features of the kidney bean indention fixture assembly  100  and indention process will be described. The indention load F 1  ( FIG. 3 ) is applied onto the tungsten axle  64  with the arms  140 . A reaction force (such as R 1  and R 2 ,  FIG. 3 ) on the outer arm  24  is provided by the fixture base  104 . The pivot axle  130  ( FIG. 6 ) is held by the pivot swivel  110  to compensate for outer arm reaction surfaces relative misalignments (in contact with the fixture base  104 ). The tungsten axle  64  is loaded through the press swivel  120  to compensate kidney bean surfaces  66 A,  66 B relative misalignment. When the indention reaches a value to allow a pin  150  to move into a latch shelf  154  provided at the latch surface  70 , the LVDT sensor  128  provides a stop signal to the press ram  118 . 
         [0032]    The kidney bean indention fixture assembly  100  provides freedom of parallelism between the pivot axle  130  to the inner arm bearing axle bore. Parallelism compensation is provided during initial setup. The components are locked from relative movement during the indention process. The kidney bean indention fixture assembly  100  further provides outer arm  24  casting variation compensation. Uniform tool displacement is provided on opposite sides after compensation. The press ram  118  is fixed. A flat ram can be acting on the carbide tool to allow inner arm length tolerance variation. A measuring device can be provided for measuring an initial latch air gap. A displacement transducer can be provided that monitors the coining mandrel. 
         [0033]    With reference now to  FIGS. 8-10 , exemplary components that may be used to carry out the latch indention process of step 2 ( FIG. 4 ) will be described. In general, a latch indention fixture assembly  200  can include a fixture base  204 , a press ram  218 , the tungsten pin  74 , an inner arm clamp  220 , an E-foot pivot axle clamp  224  and a LVDT sensor  228 . The pivot axle  130  is held by the pivot axle clamp  224  (Efoot). The inner arm  22  is clamped to be in contact with the fixture base  204 . The tungsten pin  74  is inserted into the outer arm latch bore  80  and inner arm latch shelf  154  (available subsequent to step 1, see  FIG. 6 ). An indention load is applied on the outer arm socket through the press ram  218 . A reaction force on the inner arm  22  is provided by the fixture base  204 . The shelf  154  is indented as a result of the force transferred from the tungsten pin  74 . When the indention of the shelf  154  reaches the targeted value, the LVDT  228  provides a stop signal to the press ram  218 . 
         [0034]    The latch indention fixture assembly  200  generally provides a tombstone loading structure that prevents tooling deflection side to side. A riser block is provided on the fixture base  204 . A displacement transducer monitors the coining mandrel. 
         [0035]    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.