Abstract:
A throttle control assembly which includes a valve plate made of aluminum, where the valve plate has a brass coating to substantially reduce or eliminate the effects of thermal cycling, and the probability of the occurrence of micro-welding. In one embodiment, the brass coating is applied using an electroplating process.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/090,103 filed Dec. 10, 2014. The disclosure of the above application is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates generally to a blade or plate that is part of a throttle assembly, where the plate has a coating to prevent the occurrence of micro-welds between the plate and the housing during operation. 
       BACKGROUND OF THE INVENTION 
       [0003]    Throttle control assemblies are generally known, and are used for controlling the amount of air flow into the engine during vehicle operation. These throttle control assemblies often include a plate, or blade, mounted to a shaft, which is rotated to control the amount of air flow through a housing. The housing includes an aperture, and the plate is disposed within the aperture. The material used for making the plate is typically of one of several different types of materials chosen. One of these materials commonly used is aluminum. However, a plate created using aluminum in these applications is susceptible to shifting position relative to the shaft during the life of the throttle control assembly due to thermal cycling. Furthermore, the use of aluminum may cause micro-welding to occur between the plate and the housing, affecting the operation of the plate. One way to overcome these issues is to use a brass plate, instead of aluminum, which is resistant to high temperatures. However, it is more difficult to manufacture a brass plate within the required manufacturing tolerances. 
         [0004]    Accordingly, there exists a need for a throttle control assembly has a plate that is less susceptible to being affected by thermal cycling and reduces or eliminates the probability of micro-welding to occur, and is able to manufactured to precise tolerance specifications. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention is a throttle control assembly which includes a valve plate made of aluminum, where the valve plate has a coating to substantially reduce or eliminate the probability of the occurrence of micro-welding, and the effects of thermal cycling. In one embodiment, the coating is applied using an electroplating process. The coating may be different types of materials, such as brass, or nickel. 
         [0006]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment 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 
         [0007]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0008]      FIG. 1  is a first perspective view of a throttle valve assembly, according to embodiments of the present invention; 
           [0009]      FIG. 2  is a second perspective view of a throttle valve assembly, according to embodiments of the present invention; and 
           [0010]      FIG. 3  is a top view of a plate which is part of a throttle valve assembly, according to embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0011]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0012]    A throttle control assembly according to the present invention is shown in the Figures generally at  10 . The assembly  10  includes a housing  12 , and formed as part of the housing  12  is a central port  14 , through which air passes during operation of the assembly  10 . Disposed in the central port  14  is a shaft  16 , which is rotatable. The shaft  16  includes a slot  18 , and disposed in the slot  18  is a valve member, which in this embodiment is a valve plate  20 . The valve plate  20  includes two apertures, which are in alignment with two threaded apertures formed as part of the shaft  16 . Connecting the plate  20  to the shaft  16  are two fasteners, which in this embodiment are threaded screws  26 , that are inserted through the apertures of the plate  20  and the threaded apertures of the shaft  16 , securing the valve plate  20  to the shaft  16 . 
         [0013]    The shaft  16  partially extends through the housing  12 , such that part of the shaft  14  is disposed in the port  14 . Also located in the aperture are needle bearings which support the shaft  16 , and allow for the shaft  16  to rotate relative to the housing  12 . 
         [0014]    The housing  12  also includes a cavity, and the cavity is formed as part of the portion of the housing  12  indicated at  36 . Disposed in the cavity is an actuator, which in this embodiment is an electric motor. Attached to the shaft of the motor is a first gear, or pinion gear, which is part of a gear train, having a plurality of gears, which transfers rotational force from the motor to the shaft  16 . Connected to the housing  12  is a cover  80 , and disposed between the cover  80  and the housing  12  is a seal which surrounds an outer lip formed as part of the housing  12 . The gear train is adjacent the housing  12  and is concealed by the cover  80 . The cover  80  is connected to the housing  12  using a plurality of clips  86 . There is also a secondary cover  88 , which is attached to the cover  80 . Once the cover  80  is attached to the housing  12 , the terminals for the motor can be viewed through an opening in the cover  80 . Once it is determined that the terminals of the motor  38  are in contact with the terminals formed as part of the cover  80 , the secondary cover  88  is attached to the cover  80 . 
         [0015]    The cover  80  also includes connectors  90  which are in electrical communication with the motor  38 , such that the connectors  90 , are able to be connected to a source of power. Integrally formed with the cover  80  is a lead frame which places the connectors  90  in electrical communication with a sensor. 
         [0016]    In operation, a return spring biases the gear train, and therefore the shaft  16  and valve plate  20  towards a closed position, such that the central port  14  is substantially closed, or blocked completely, depending upon how the assembly  10  is configured. When a current is applied to the motor, the gears in the gear train are rotated. To rotate the valve plate  20 , the force applied to the gear train by the return spring is overcome. The amount of rotation in the gear train is in proportion to the amount of current applied to the motor, which overcomes the force applied to the gear train by the return spring. 
         [0017]    As the gears in the gear train are rotated, the shaft  16  is rotated as well, rotating the plate  20 , and controlling the amount of air flow through the central port  14 . The amount of rotation of the gear train is detected by the sensor, such that the valve plate  20  may be placed in a desired position. 
         [0018]    The plate  20  in this embodiment is an aluminum plate, which has a brass coating, shown generally at  98 . The use of aluminum in manufacturing the plate  20  allows the plate  20  to be sized to tight manufacturing tolerances, and the brass coating  98  provides the advantage of minimizing the chances of the formation of micro-welds between the plate  20  and the port  14 , and allows the plate  20  to be used in high-performance applications, either in applications such as the throttle control assembly  10 , as described above, or in any other type of application requiring a valve plate. In one embodiment, the shaft  16  is about eight millimeters in diameter, but it is within the scope of the invention that other diameter dimensions may be used, such as, but not limited to diameters ranging from six millimeters to twelve millimeters and above in diameter. The plate  20  includes a plurality of apertures  100  which facilitate the plate  20  being able to deflect relative to the shaft  16  during thermal cycling without changing the location of the plate  20  relative to the shaft  16 . The width  102  of each of the apertures  100  is about six millimeters, such that there is an overlap of about one millimeter (on each side of the apertures  100 ) between the apertures  100  and the shaft  16 , as shown in  FIG. 3 . In one embodiment, the brass coating  98  is only applied to the outer diameter of the plate  20 , and in another embodiment, the brass coating  98  is applied to the entire surface of the plate  20 . The brass coating  98  may be applied to the plate  20  through the process of electroplating, or other processes as well. Furthermore, other types of coatings, instead of the brass coating  98 , is applied to the plate  20  to make the plate  20  be suitable for other embodiments. These other types of coatings may be nickel coatings, or the like. In yet additional embodiments, certain types of surface modifications may be used, instead of the coating  98 , such as etching or any other type of surface modification. 
         [0019]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.