Abstract:
A supercharger constructed in accordance to one example of the present disclosure can include a drive shaft, an input shaft, a first gear, a second gear, a first clutch and a second clutch. The second gear can have a different ratio than the first gear. The first clutch assembly can selectively couple rotatable input from the drive shaft to rotation of the input shaft through the first gear at the first drive ratio. The second clutch assembly can selectively couple rotatable input from the drive shaft to rotation of the input shaft through the second gear at a second drive ratio. The input shaft can operate in each of (i) a high speed through driving rotation of the first gear; (ii) a low speed through driving rotation of the second gear and (iii) no speed wherein both of the first and second gears are disconnected with the drive shaft.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application No. PCT/US2014/058776 filed on Oct. 2, 2014, which claims the benefit of U.S. Patent Application No. 61/889,819 filed on Oct. 11, 2013 and U.S. Patent Application No. 61/951,149 filed on Mar. 11, 2014. The disclosures of the above applications are incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates generally to superchargers and more particularly to a supercharger having multiple speeds. 
       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 supercharger constructed in accordance to one example of the present disclosure can include a drive shaft, an input shaft, a first gear, a second gear, a first clutch and a second clutch. The drive shaft can be connected to a pulley. The input shaft can provide a rotatable input to the supercharger. The first gear can be coupled for rotation with the input shaft. The second gear can be coupled for rotation with the input shaft. The second gear can have a different gear ratio than the first gear. The first clutch assembly can selectively couple rotatable input from the drive shaft to rotation of the input shaft through the first gear at the first drive ratio. The second clutch assembly can selectively couple rotatable input from the drive shaft to rotation of the input shaft through the second gear at a second drive ratio distinct from the first drive ratio. The input shaft can operate in each of (i) a high speed through driving rotation of the first gear; (ii) a low speed through driving rotation of the second gear and (iii) no speed wherein both of the first and second gears are disconnected from driving engagement with the drive shaft. 
         [0006]    According to additional features, the first clutch assembly can include a first clutch rotor mounted for rotation with the drive shaft. A first clutch armature can be unconnected to the first clutch rotor. A first clutch coil can be spaced adjacent to the first clutch rotor. The first clutch coil can be configured to produce first magnetic lines of flux causing the first clutch rotor to be attracted to the first clutch armature causing a rotatable input from the drive shaft to be communicated to the input shaft through the first gear. 
         [0007]    According to additional features, the second clutch assembly can include a second clutch rotor mounted for rotation with the drive shaft. A second clutch armature can be unconnected to the second clutch rotor. A second clutch coil can be spaced adjacent to the second clutch rotor. The second clutch coil can be configured to produce second magnetic lines of flux causing the second clutch rotor to be attracted to the second clutch armature causing a rotatable input from the drive shaft to be communicated to the input shaft through the second gear. 
         [0008]    According to other features, the supercharger can further comprise a first transfer gear selectively coupled for rotation with the drive shaft and meshed for rotation with the first gear. The first transfer gear can be fixed for concurrent rotation with the drive shaft based on the first clutch assembly operating in the engaged position. A second transfer gear can be coupled for rotation with the drive shaft and meshed for rotation with the second gear. The second transfer gear can be fixed for concurrent rotation with the drive shaft based on the second clutch assembly operating in an engaged position. An electronic control unit can provide an electrical signal to the first and second clutch assemblies based on a sensor reading corresponding to vehicle parameters. 
         [0009]    A supercharger according to another configuration of the present disclosure can include a drive shaft connected to a pulley. An input shaft can provide a rotatable input to the supercharger. A first gear can be coupled for rotation with the input shaft. A second gear can be coupled for rotation with the input shaft. The second gear can have a different gear ratio than the first gear. A first clutch assembly can selectively couple rotatable input from the drive shaft to rotation of the input shaft through the first gear at a first drive ratio. The first clutch assembly can have a first clutch rotor mounted for rotation with the drive shaft. A first clutch armature can be unconnected to the first clutch rotor. A first clutch coil can be spaced adjacent to the first clutch rotor. A second clutch assembly can selectively couple rotatable input from the drive shaft to rotation of the input shaft through the second gear at a second drive ratio distinct from the first drive ratio. The second clutch assembly can have a second clutch rotor mounted for rotation with the drive shaft. A second clutch armature can be unconnected to the second clutch rotor. A second clutch coil can be spaced adjacent to the second clutch rotor. The supercharger can operate in each of (i) a high speed through driving rotation of the first gear, (ii) a low speed through driving rotation of the second gear; and (iii) no speed wherein both of the first and second gears are disconnected from driving engagement with the drive shaft. 
         [0010]    According to additional features, the first clutch coil can be configured to produce first magnetic lines of flux causing the first clutch rotor to be attracted to the first clutch armature causing a rotatable input from the drive shaft to be communicated to the input shaft through the first gear. The second clutch coil can be configured to produce second magnetic lines of flux causing the second clutch rotor to be attracted to the second clutch armature causing a rotatable input from the drive shaft to be communicated to the input shaft through the second gear. A first transfer gear can be selectively coupled for rotation with the drive shaft and meshed for rotation with the first gear. The first transfer gear can be fixed for concurrent rotation with the drive shaft based on the first clutch assembly operating in the engaged position. A second transfer gear can be selectively coupled for rotation with the drive shaft and meshed for rotation with the second gear. The second transfer gear can be fixed for concurrent rotation with the drive shaft based on the second clutch assembly operating in the engaged position. An electronic control unit can provide an electrical signal to the first and second clutch assemblies based on at least one sensor reading corresponding to at least one vehicle parameter. 
         [0011]    A method of operating a supercharger is provided. The method can include selectively and alternatively: (i) engaging a first clutch assembly of the supercharger thereby operating the supercharger at a first speed ratio including transmitting a torque from a drive shaft, to a first transfer gear, to a first gear and to an input shaft; (ii) engaging a second clutch assembly of the supercharger thereby operating the supercharger at a second speed ratio, distinct from the first speed ratio, including transmitting a torque from a drive shaft, to a second transfer gear, to a second gear and to the input shaft, (iii) disengaging the first and second clutch assemblies of the supercharger thereby providing no torque input to the input shaft. 
     
    
     
       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 a schematic illustration of the supercharger of  FIG. 1  illustrating first and second electromagnetic clutches that independently communicate a rotatable input to a first and a second respective gear; 
           [0015]      FIG. 3  is a perspective view of a supercharger having first and second electromagnetic clutch assemblies according to one example of the present disclosure; 
           [0016]      FIG. 4  is a partial cross-sectional view of the supercharger and electromagnetic clutch assemblies of  FIG. 3 ; 
           [0017]      FIG. 5  is a partial cross-sectional view of the supercharger and electromagnetic clutch assemblies of  FIG. 4  showing a first torque path with both of the first and second clutch assemblies disengaged; 
           [0018]      FIG. 6  is a partial cross-sectional view of the supercharger and electromagnetic clutch assemblies of  FIG. 4  showing a second (“high-speed”) torque path with the first clutch assembly engaged and the second clutch assembly disengaged; and 
           [0019]      FIG. 7  is a partial cross-sectional view of the supercharger and electromagnetic clutch assemblies of  FIG. 4  showing a third (“low-speed”) torque path with the second clutch assembly engaged and the first clutch assembly disengaged. 
       
    
    
     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  50  of the blower  26  is shown. The input section  50  can include a drive shaft  52 , a pulley  54 , a dual clutch assembly  60 , a first gear  70 , a second gear  72  and an input shaft  76 . In the example provided, the pulley  54  can be configured to transmit torque from the engine crankshaft (not shown) to the drive shaft  52 . 
         [0025]    The dual clutch assembly  60  can generally include a first clutch assembly  80  and a second clutch assembly  82 . The first clutch assembly  80  can include a first armature  90 , a first coil  92  and a first rotor  94 . The second clutch assembly  82  can include a second armature  100 , a second coil  102  and a second rotor  104 . A first transfer gear  110  can be meshed for rotation with the first gear  70 . A second transfer gear  112  can be meshed for rotation with the second gear  72 . 
         [0026]    The first and second gears  70  and  72  can provide distinct drive ratios to the input shaft  76 . In the example provided, the first gear  70  can be a high-gear and the second gear  72  can be a low-gear. Other configurations are contemplated. 
         [0027]    The first clutch assembly  80  can move from a disengaged position to an engaged position. In the disengaged position, a rotational input from the drive shaft  52  is not transferred to the first gear  70 . In the engaged position, a rotational input from the drive shaft  52  is transferred to the first gear  70 . 
         [0028]    In one configuration, the first clutch assembly  80  can move to the engaged position by applying an electrical current and/or voltage to the first clutch coil  92  to generate a magnetic field in the vicinity of the first clutch coil  92  and produce magnetic lines of flux. The intensity of the magnetic field may be proportional to the level of current provided. This flux may then be transferred through the small working gap between the first clutch coil  92  and the first clutch rotor  94 . The first clutch rotor  94  may therefore become magnetized and set up a magnetic loop that attracts the first clutch armature  90 . The first clutch armature  90  may then be urged against the first clutch rotor  94  and a frictional force may be applied at contact and the load on the first clutch armature  90  may be accelerated to match the speed of the first clutch rotor  94 . As a result, the rotational input of the drive shaft  52  is communicated through the first transfer gear  110  and the first gear  70  and ultimately to the input shaft  76 . When the first clutch assembly  80  is engaged, the supercharger  26  receives a rotatable input from the first or “high” gear  70  and is operating at a “high speed”. 
         [0029]    The second clutch assembly  82  can move from a disengaged position to an engaged position. In the disengaged position, a rotational input from the drive shaft  52  is not transferred to the second gear  72 . In the engaged position, a rotational input from the drive shaft  52  is transferred to the second gear  72 . 
         [0030]    In one configuration, the second clutch assembly  82  can move to the engaged position by applying an electrical current and/or voltage to the second clutch coil  102  to generate a magnetic field in the vicinity of the second clutch coil  102  and produce magnetic lines of flux. The intensity of the magnetic field may be proportional to the level of current provided. This flux may then be transferred through the small working gap between the second clutch coil  102  and the second clutch rotor  104 . The second clutch rotor  104  may therefore become magnetized and set up a magnetic loop that attracts the second clutch armature  100 . The second clutch armature  100  may then be urged against the second clutch rotor  104  and a frictional force may be applied at contact and the load on the clutch armature  100  may be accelerated to match the speed of the second clutch rotor  104 . As a result, the rotational input of the drive shaft  52  is communicated through the second transfer gear  112  and the second gear  72  and ultimately to the input shaft  76 . When the second clutch assembly  82  is engaged, the supercharger receives a rotatable input from the second or “low” gear  72  and is operating at a “low speed”. 
         [0031]    The first and second clutch coils  92  and  102  may be controlled by an electronic control unit (ECU)  130  that provides an electrical signal to the first and second clutch coils  92  and  102 . The ECU  130  may process inputs  132 , such as for example, but not limited to, sensor readings corresponding to vehicle parameters and process the input according to log rules to determine the appropriate electrical signal to provide to the first and second clutch coils  92  and  102 . The ECU  130  may comprise a microprocessor having sufficient memory to store the logic rules (e.g., in the form of a computer program) for controlling operation of the first and second clutch assemblies  80  and  82 . The ECU  130  can provide logic that prevents both of the first and second clutch assemblies  80  and  82  from being concurrently engaged. 
         [0032]      FIG. 5  is a schematic illustration of the dual clutch assembly  60  when both the first and second clutch assemblies  80  and  82  are disengaged. When the first and second clutch assemblies  80  and  82  are both in the disengaged positions, no rotatable input is transferred to the input shaft  76 . A torque path  140  created from a rotatable input from the pulley  54  will merely rotate the drive shaft  52 . Neither of the first and second transfer gears  110  and  112  are fixed for concurrent rotation with the drive shaft  52 . In this regard, torque is not communicated to either of the first and second gears  70  and  72 . The supercharger  26  is therefore “off” and not operating. 
         [0033]      FIG. 6  is a schematic illustration of the dual clutch assembly  60  when the first clutch assembly  80  is in the engaged position and the second clutch assembly  82  is in the disengaged position. When the first clutch assembly  80  is in the engaged position, the first transfer gear  110  is fixed for concurrent rotation with the drive shaft  52  while the second transfer gear  112  is decoupled from the drive shaft  52 . A rotatable input is transferred from the drive shaft  52 , to the first transfer gear  110 , to the first gear  70  and to the input shaft  76 . A “high-speed” torque path  142  is illustrated in  FIG. 6  from the drive shaft  52 , to the first transfer gear  110 , to the first gear  70  and to the input shaft  76 . 
         [0034]      FIG. 7  is a schematic illustration of the dual clutch assembly  60  when the second clutch assembly  82  is in the engaged position and the first clutch assembly  80  is in the disengaged position. When the second clutch assembly  82  is in the engaged position, the second transfer gear  112  is fixed for concurrent rotation with the drive shaft  52  while the first transfer gear  110  is decoupled from the drive shaft  52 . A rotatable input is transferred from the drive shaft  52 , to the second transfer gear  112 , to the second gear  72  and to the input shaft  76 . A “low-speed” torque path  144  is illustrated in  FIG. 7  from the drive shaft  52 , to the second transfer gear  112 , to the second gear  72  and to the input shaft  76 . 
         [0035]    The dual clutch assembly  60  of the input section  50  can therefore provide a “low speed” by engaging the first clutch assembly  80 ; a “high speed” by engaging the second clutch assembly  82 ; and an “off” position (no speed) when neither of the first or second clutch assemblies  80  and  82  are engaged. 
         [0036]    The foregoing description of the embodiments 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 embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, 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.