Abstract:
A coupling assembly arranged between an input shaft and a rotor shaft of a supercharger constructed in accordance to one example of the present disclosure includes a coupling hub and a plurality of pins. The coupling hub can have a series of lobes. Adjacent lobes of the series of lobes can define a plurality of openings. The coupling hub can further define a mounting bore therein. The plurality of pins can have first ends and second ends. The first ends can be correspondingly received by the plurality of openings. The second ends can be received by the rotor shaft. The input shaft can be directly mounted into the mounting bore of the coupling hub for concurrent rotation therewith.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application No. PCT/US2015/048842 filed on Sep. 8, 2015, which claims the benefit of Indian Patent Application No. 2580/DEL/2014 filed on Sep. 9, 2014. The disclosure of the above application is incorporated herein by reference. 
       FIELD 
       [0002]    The present disclosure relates generally to superchargers and more particularly to a coupling between an input shaft and a rotor shaft on a supercharger. 
       BACKGROUND 
       [0003]    Rotary blowers of the type to which the present disclosure relates are referred to as “superchargers” because they effectively super charge the intake of the engine. One supercharger configuration is generally referred to as a Roots-type blower that transfers volumes of air from an inlet port to an outlet port. A Roots-type blower includes a pair of rotors which must be timed in relationship to each other, and therefore, are driven by meshed timing gears which are potentially subject to conditions such as gear rattle and bounce. Typically, a pulley and belt arrangement for a Roots blower supercharger is sized such that, at any given engine speed, the amount of air being transferred into the intake manifold is greater than the instantaneous displacement of the engine, thus increasing the air pressure within the intake manifold and increasing the power density of the engine. 
         [0004]    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 
       [0005]    A coupling assembly arranged between an input shaft and a rotor shaft of a supercharger constructed in accordance to one example of the present disclosure includes a coupling hub and a plurality of pins. The coupling hub can have a series of lobes. Adjacent lobes of the series of lobes can define a plurality of openings. The coupling hub can further define a mounting bore therein. The plurality of pins can have first ends and second ends. The first ends can be correspondingly received by the plurality of openings. The second ends can be received by the rotor shaft. The input shaft can be directly mounted into the mounting bore of the coupling hub for concurrent rotation therewith. 
         [0006]    According to additional features, the first end of the input shaft can be press fit into the mounting bore of the coupling hub. The second ends of the plurality of pins can be directly received by corresponding openings on the rotor shaft. The series of lobes can consist of three lobes. Additional lobes may be incorporated according to torque transfer requirements for a particular application. The plurality of openings can consist of three openings. The plurality of pins can consist of three pins. Additional pins may be incorporated according to torque transfer requirements. 
         [0007]    According to other features, the coupling assembly can further comprise the input shaft. The input shaft can include a first end portion, a second end portion and an intermediate portion. The intermediate portion can connect the first end portion and the second end portion. The first end portion can be coupled to a pulley. The second end portion can be directly mounted into the mounting bore of the coupling hub. The second end portion can have a reduced diameter as compared to the intermediate portion. Each lobe of the series of lobes can have a rib formed thereon, the rib configured to strengthen the coupling hub. The coupling hub can be one-piece. The coupling hub can be formed of over-molded plastic having a metal insert. The metal insert can have a hexagonal outer profile. 
         [0008]    According to still other features the metal insert can comprise a series of first planar surfaces that oppose a complementary series of second planar surfaces on the hub body. The first and second planar surfaces cooperate to resist rotation between the hub body and the insert. The insert can further comprise an undercut geometry thereon. The undercut geometry can include a series of insert portions thereon configured to resist axial slip between the insert and the hub body. The plurality of openings can be closed around a circumference of the hub body. 
         [0009]    A coupling assembly arranged between an input shaft and a rotor shaft of a supercharger and constructed in accordance to another example of the present disclosure can include a coupling hub and a plurality of pins. The coupling hub can have a series of lobes wherein adjacent lobes of the series of lobes define a plurality of openings. The coupling hub can further define a mounting bore therein. The coupling hub is one-piece and comprises a hub body formed of plastic and an insert formed of metal. The hub body can have a series of first planar portions that oppose a complementary series of second planar surfaces on the hub body. The first and second planar surfaces cooperate to resist relative rotation between the hub body and the insert. 
         [0010]    The plurality of pins can have first ends and second ends. The first ends are correspondingly received by the plurality of openings and the second ends are received by the rotor shafts. The input shaft is directly mounted into the mounting bore of the coupling hub for concurrent rotation therewith. 
         [0011]    According to other features, the insert includes an undercut geometry thereon. The undercut geometry includes a series of inset portions thereon configured to resist axial slip between the insert and the hub body. The plurality of openings are closed around a circumference of the hub body. The coupling assembly can further include an input shaft that has a first end portion, a second end portion and an intermediate portion that connects the first end portion and the second end portion. The first end portion is coupled to a pulley and the second end portion is directly mounted into the mounting bore of the coupling hub. The second end portion has a reduced diameter as compared to the intermediate portion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0013]      FIG. 1  is a schematic illustration of an intake manifold assembly having a positive displacement blower or supercharger constructed in accordance to one example of the present disclosure; 
           [0014]      FIG. 2  is an enlarged, fragmentary, axial cross-section of an input section of the supercharger of  FIG. 1  and having a coupling assembly used to couple an input shaft and a rotor shaft according to prior art. 
           [0015]      FIG. 3  is an enlarged, fragmentary, axial cross-section of the input section of the supercharger of  FIG. 1  and having a coupling assembly used to couple an input shaft and a rotor shaft and constructed in accordance to one example of the present disclosure; 
           [0016]      FIG. 4  is front perspective view of the coupling assembly of  FIG. 3  including a coupling hub and a plurality of coupling pins shown coupled between the input shaft and a first timing gear of the supercharger of  FIG. 3 ; 
           [0017]      FIG. 5  is a front perspective view of the coupling hub of the coupling assembly of  FIG. 4 ; 
           [0018]      FIG. 6  is a front perspective exploded view of a coupling hub constructed in accordance to additional features of the present disclosure; and 
           [0019]      FIG. 7  is a front perspective view of the coupling hub of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    With initial reference to  FIG. 1 , a schematic illustration of an exemplary intake manifold assembly, including a Roots blower supercharger and bypass valve arrangement is shown. An engine  10  can include a plurality of cylinders  12 , and a reciprocating piston  14  disposed within each cylinder and defining an expandable combustion chamber  16 . The engine  10  can include intake and exhaust manifold assemblies  18  and  20 , respectively, for directing combustion air to and from the combustion chamber  16 , by way of intake and exhaust valves  22  and  24 , respectively. 
         [0021]    The intake manifold assembly  18  can include a positive displacement rotary blower  26 , or supercharger of the Roots type. Further description of the rotary blower  26  may be found in commonly owned U.S. Pat. Nos. 5,078,583 and 5,893,355, which are expressly incorporated herein by reference. The blower  26  includes a pair of rotors  28  and  29 , each of which includes a plurality of meshed lobes. The rotors  28  and  29  are disposed in a pair of parallel, transversely overlapping cylindrical chambers  28   c  and  29   c , respectively. The rotors  28  and  29  may be driven mechanically by engine crankshaft torque transmitted thereto in a known manner, such as by a drive belt (not specifically shown). The mechanical drive rotates the blower rotors  28  and  29  at a fixed ratio, relative to crankshaft speed, such that the displacement of the blower  26  is greater than the engine displacement, thereby boosting or supercharging the air flowing to the combustion chambers  16 . 
         [0022]    The blower  26  can include an inlet port  30 , which receives air or air-fuel mixture from an inlet duct or passage  32 , and further includes a discharge or outlet port  34 , directing the charged air to the intake valves  22  by means of a duct  36 . The inlet duct  32  and the discharge duct  36  are interconnected by means of a bypass passage, shown schematically at reference  38 . If the engine  10  is of the Otto cycle type, a throttle valve  40  can control air or air-fuel mixture flowing into the intake duct  32  from a source, such as ambient or atmospheric air, in a well know manner. Alternatively, the throttle valve  40  may be disposed downstream of the supercharger  26 . 
         [0023]    A bypass valve  42  is disposed within the bypass passage  38 . The bypass valve  42  can be moved between an open position and a closed position by means of an actuator assembly  44 . The actuator assembly  44  can be responsive to fluid pressure in the inlet duct  32  by a vacuum line  46 . The actuator assembly  44  is operative to control the supercharging pressure in the discharge duct  36  as a function of engine power demand. When the bypass valve  42  is in the fully open position, air pressure in the duct  36  is relatively low, but when the bypass valve  42  is fully closed, the air pressure in the duct  36  is relatively high. Typically, the actuator assembly  44  controls the position of the bypass valve  42  by means of a suitable linkage. The bypass valve  42  shown and described herein is merely exemplary and other configurations are contemplated. In this regard, a modular (integral) bypass, an electronically operated bypass, or no bypass may be used. 
         [0024]    With specific reference now to  FIG. 2 , an input section  48  of the blower  26  is shown according to one prior art configuration. The input section  48  can include a housing member  50 , which forms a forward end of the chambers  28   c  and  29   c . Attached to the housing member  50  is a forward housing  52  within which is disposed an input shaft  54 . The input shaft  54  is supported within the forward housing  52  by first and second bearings  56 A and  56 B, respectively. Rotatably supported by the housing member  50  are a pair of rotor shafts  58  and  60 , upon which is mounted the respective blower rotors  28  and  29  (see  FIG. 1 ). A hub pin subassembly  62  couples the input shaft  54  to the first rotor shaft  58 . In one example, a first hub  64  can couple the input shaft  54  to the coupling assembly  62  on a first end and a second hub  66  can couple the first rotor shaft  58  to the coupling assembly  62  on an opposite end. A first timing gear  70  may be mounted on a forward end of the first rotor shaft  58 . The first timing gear  70  may define teeth that are in meshed engagement with gear teeth of a second timing gear  72  that is mounted on the second rotor shaft  60 . The second rotor shaft  60  can be in driving engagement with the blower rotor  29 . 
         [0025]    In one configuration, positive torque is transmitted from an internal combustion engine (of the periodic combustion type) to the input shaft  54  by any suitable drive means, such as a belt and pulley drive system including a pulley  76 . Torque is transmitted from the input shaft  54  to the first rotor shaft  58  through the coupling assembly  62 . When the engine  10  is driving the timing gears and the blower rotors  28  and  29 , such is considered to be transmission of positive torque. On the other hand, whenever the momentum of the rotors  28  and  29  overruns the input from the input shaft  54 , such is considered to be the transmission of negative torque. 
         [0026]    With additional reference now to  FIGS. 3-5 , a coupling assembly  110  constructed in accordance to one example of the present disclosure will be described in greater detail. The coupling assembly  110  can replace the hub pin subassembly  62  described above. As will become appreciated, the coupling assembly  110  provides a simpler configuration as compared to the hub pin subassembly shown in  FIG. 2  while using less parts and therefore reduced piece cost and assembly cost. The coupling assembly  110  is shown in a blower  126  where like reference numerals increased by  100  are used. 
         [0027]    A first timing gear  170  may be mounted on a forward end of the first rotor shaft  158 . The first timing gear  170  may define teeth that are in meshed engagement with gear teeth of a second timing gear  172  that is mounted on the second rotor shaft  160 . The second rotor shaft  160  can be in driving engagement with the blower rotor  29  ( FIG. 1 ). 
         [0028]    The input section  148  can include a housing member  150 , which forms a forward end of the chambers  28   c  and  29   c  (see  FIG. 1 ). Attached to the housing member  150  is a forward housing  152  within which is disposed an input shaft  154 . The input shaft  154  is supported within the forward housing  152  by first and second bearings  156 A and  156 B, respectively. Rotatably supported by the housing member  150  are a pair of rotor shafts  158  and  160 , upon which is mounted the respective blower rotors  28  and  29  (see  FIG. 1 ). 
         [0029]    The coupling assembly  110  includes a coupling hub  180  and a plurality of pins  182 . The coupling hub  180  can be one-piece or unitary. The coupling assembly  110  couples the input shaft  154  to the first rotor shaft  158 . The input shaft  154  can include a first end portion  190 , a second end portion  192  and an intermediate section  194 . In the example shown (see  FIGS. 3 and 4 ), the first end portion  190  is coupled to the pulley  176 . The second end portion  192  is coupled to the coupling hub  180 . The second end portion  192  can have a stepped down or reduced diameter as compared to the intermediate section  194 . The second end portion  192  can be press-fit into the coupling hub  180  (see also  FIG. 3 ). Explained further, the coupling hub  180  can have a hub body  210  that defines a central bore  212  configured to receive the second end portion  192  of the input shaft  154 . The hub body  210  can be formed of over-molded plastic having a metal insert  214 . The hub body  210  can further have a plurality of lobes  220 ,  222  and  224 . Additional or fewer lobes may be incorporated according to torque transfer requirements of a particular application. Adjacent lobes  220  and  222  define a first opening or pin receiver  230 . Adjacent lobes  222  and  224  define a second opening pin receiver  232 . Adjacent lobes  224  and  220  define a third opening or pin receiver  234 . The lobes  220 ,  222  and  224  can include respective ribs  220 A,  222 A and  224 A formed thereon. The ribs  220 A,  222 A and  224 A strengthen the coupling hub  180 . The collective pin receivers  230 ,  232  and  234  are configured to selectively receive first ends of pins  240  (only one specifically shown in  FIG. 3  and two shown in  FIG. 4 ). Opposite ends of the pins  240  are received by the first timing gear  170 . The pin receivers  230 ,  232  and  234  can be closed around a circumference of the hub body  210 . 
         [0030]    In one configuration, positive torque is transmitted from an internal combustion engine (of the periodic combustion type) to the input shaft  154  by any suitable drive means, such as a belt and pulley drive system including the pulley  176 . Torque is transmitted from the input shaft  154  to the first rotor shaft  158  through the coupling assembly  110 . When the engine  10  is driving the timing gears and the blower rotors  28  and  29 , such is considered to be transmission of positive torque. On the other hand, whenever the momentum of the rotors  28  and  29  overruns the input from the input shaft  154 , such is considered to be the transmission of negative torque. 
         [0031]    With reference to  FIGS. 6 and 7 , a coupling hub  302  constructed in accordance to additional features of the present disclosure will be described. Unless otherwise explained herein, the coupling hub  302  can be constructed similar to the coupling hub  180 . The coupling hub  302  can have a hub body  310  that defines a central bore  312  configured to receive the second end portion  192  of the input shaft  154 . The hub body  310  can be formed of over-molded plastic having a metal insert  314 . The metal insert  314  can have a hexagonal outer profile that resists rotation relative to the remainder of the hub body  310 . Explained further, the hexagonal outer profile includes a series of six planer surfaces  316  that oppose complementary planar surfaces  317  on the hub body  310 . The planar surfaces  316  and  317  cooperate to inhibit relative rotation of the metal insert  314  and the hub body  310 . Further, the metal insert  314  includes an undercut geometry that includes inset portions  318  to resist axial slip between the metal insert  314  of the hub body  310 . It will be appreciated that material of the hub body  310  will extend into the inset portions  318 . 
         [0032]    The hub body  310  can further have a plurality of lobes  320 ,  322  and  324 . Additional or fewer lobes may be incorporated according to torque transfer requirements of a particular application. Adjacent lobes  320  and  322  define a first opening or pin receiver  330 . Adjacent lobes  322  and  324  define a second opening pin receiver  332 . Adjacent lobes  324  and  320  define a third opening or pin receiver  334 . The lobes  320 ,  322  and  324  can include respective ribs  320 A,  322 A and  324 A formed thereon. The ribs  320 A,  322 A and  324 A strengthen the coupling hub  302 . The collective pin receivers  330 ,  332  and  334  are configured to selectively receive first ends of pins  240  (only one specifically shown in  FIG. 3  and two shown in  FIG. 4 ). Opposite ends of the pins  240  are received by the first timing gear  170 . In one example the hub body  310  can be formed of Polyether ether ketone (PEEK) and the insert can be formed of steel such as  4140  steel. Other materials are contemplated. 
         [0033]    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.