Abstract:
One aspect according to the present disclosure includes a first coupling device and a second coupling device. The first coupling device can mechanically couple the canister and the accessory component to each other. The second coupling device can couple the canister and the accessory component to allow flow communication with each other. The second coupling device is operable in conjunction with the operation of the first coupling device.

Description:
[0001]    This application claims priority to Japanese patent application serial number 2008-278266, the contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a device for mounting an accessory component on a canister so that the accessory component can communicate with the canister filled with an adsorption material for adsorbing fuel vapor generated within a fuel tank. 
         [0004]    2. Description of the Related Art 
         [0005]    A known device for mounting an accessory component on a canister is disclosed, for example, in Japanese Laid-Open Patent Publication 2006-308045. As shown in  FIG. 6 , a fuel vapor passage  101 , a purge passage  104  and an atmospheric passage  106  are connected to a canister  100 . The fuel vapor passage  101  introduces fuel vapor produced within a fuel tank T into the canister  100 . The purge passage  104  is connected to an intake air passage  103  of an engine. The atmospheric passage  106  is opened into the atmosphere. An electromagnetic valve  107  is provided in the purge passage  104 . The electromagnetic valve  107  closes the purge passage  104  when the engine is not operating. The electromagnetic valve  107  opens when the engine is operating. The electromagnetic valve  107  is mounted with a bolt on a case of the canister  100  and is connected to a purge port  100   p  of the canister  100 . 
         [0006]    However, the known mounting device for mounting an accessory component, such as the electromagnetic valve  107 , with bolts on the canister  100  requires troublesome tightening operations of bolts and a number of assembling steps. More specifically, if weight of the accessory component is heavy, it is necessary to increase the number of bolts to stably fix the accessory component to the canister. Accordingly, required assembling steps for mounting the accessory component may be increased. 
         [0007]    Therefore, there is a need in the art for a mounting device that can stably fix an accessory component to a canister. 
       SUMMARY OF THE INVENTION 
       [0008]    One aspect according to the present disclosure includes a first coupling device and a second coupling device. The first coupling device can mechanically coupling the canister and the accessory component to each other. The second coupling device can couple the canister and the accessory component to allow flow communication with each other. The second coupling device is operable in conjunction with the operation of the first coupling device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a schematic structural view showing a fuel vapor processing apparatus including a canister with an accessory component mounting device according to an embodiment of the present disclosure and a pump unit that is the accessory component of the canister; 
           [0010]      FIG. 2  is a plan view showing the canister to which the pump unit is mounted; 
           [0011]      FIG. 3  is a front view of  FIG. 2  as viewed from a direction identified with III-III arrows in  FIG. 2 ; 
           [0012]      FIG. 4(A)  shows a side view of  FIG. 2  as viewed from a direction identified with IV-IV arrows in  FIG. 2 ; 
           [0013]      FIG. 4(B)  shows a side view showing a mounting process of the pump unit to the canister; 
           [0014]      FIG. 4(C)  shows a vertical sectional view of a portion C in  FIG. 4(A) ; 
           [0015]      FIG. 4(D)  shows a vertical sectional view of a portion D in  FIG. 4(A) ; 
           [0016]      FIG. 5(A)  shows a plan view of the pump unit; 
           [0017]      FIGS. 5(B) ,  5 (C),  5 (D), and  5 (E) show side views of the pump unit, and 
           [0018]      FIG. 6  is a schematic structural view showing a known fuel vapor processing apparatus. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Each of the additional features and teachings disclosed above and below may be utilized separately or in conjunction with other features and teachings to provide improved devices for mounting accessory components to canisters. Representative examples of the present disclosure, which examples utilize many of these additional features and teachings both separately and in conjunction with one another, will now be described in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Moreover, various features of the representative examples and the dependent claims may be combined in ways that are not specifically enumerated in order to provide additional useful embodiments of the present teachings. 
         [0020]    In one embodiment, a mounting device for mounting an accessory component to a canister may enable to communicate between the accessory component and the canister. The canister is filled with an adsorption material for adsorbing fuel vapor generated within a fuel tank. The mounting device includes a communicating pipe receiver and an outer wall provided on the canister. The communicating pipe receiver is connectible to a communicating pipe of the accessory component. The outer wall surrounds the communicating pipe receiver. The communicating pipe is connected to the communicating pipe receiver as a housing of the accessory component is fitted into the outer wall of the canister in an axial direction of the communicating pipe. An engagement mechanism is provided between the outer wall of the canister and the housing of the accessory component. The engaging mechanism can elastically engage the outer wall of the canister and the housing of the accessory component with each other and can fix the accessory component to the canister when the housing of the accessory component is fitted into the outer wall to reach a predetermined position. 
         [0021]    According to this arrangement, the engagement mechanism is provided between the outer wall of the canister and the housing of the accessory component. As the housing is fitted into the outer wall of the canister by a predetermined depth, the engaging mechanism elastically engages to fix the accessory component to the canister. In addition, as the housing is fitted into the outer wall of the canister  20  by the predetermined depth, the communicating pipe of the accessory component is connected to the communicating pipe receiver of the canister. 
         [0022]    In this way, the housing of the accessory component may be fixed to the canister by fitting the housing into the outer wall of the canister by a predetermined depth. Therefore, the number of steps required for assembling the accessory component to the canister may be reduced compared to that required for fixing the accessory component to the canister with bolts. Further, because the accessory component is fitted into the outer wall of the canister, the accessory component may be stably fixed to the canister even in the case that the weight of the accessory component is heavy. 
         [0023]    In another embodiment, the accessory component mounting device may further include a projection formed on an outer peripheral surface of the housing of the accessory component and extending parallel to the axial direction of the communicating pipe and a concave formed on an inner peripheral surface of the outer wall of the canister and extending parallel to the axial direction of the communicating pipe. The concave is positioned to correspond to a position of the projection for engagement with the projection. 
         [0024]    Therefore, by fitting the housing of the accessory component into the outer wall of the canister in such a way that the projection of the housing is aligned with the concave of the outer wall of the canister, it is possible to eliminate improper assembling. 
         [0025]    The projection of the housing may be constituted by a port of the accessory component. 
         [0026]    A plural number of linear protrusions may be formed on the outer peripheral surface of the housing of the accessory component. Outer end surfaces of the linear protrusions may contact with the inner peripheral surface of the outer wall of the canister. Due to these protrusions, shifting movement of the accessory component relative to the outer wall of the canister can be prevented. 
       First Embodiment 
       [0027]    A device for mounting an accessory component on a canister according to a first embodiment of the present disclosure will now be described with reference to  FIGS. 1 to 3 ,  4 (A) to  4 (D) and  5 (A) to  5 (E). The accessory component mounted to the canister in the present embodiment is a pump unit used for a leak check of the canister when an engine of an automobile is not operating. 
       &lt;Fuel Vapor Processing Apparatus&gt; 
       [0028]    A fuel vapor processing apparatus  10  can prevent fuel vapor generated in a fuel tank T from leaking into the atmosphere. As shown in  FIG. 1 , the fuel vapor processing apparatus  10  includes a canister  20 , a fuel vapor passage  14 , a purge passage  16  and an atmospheric passage  18 . The canister  20  is filled with a fuel adsorption material  12  for adsorbing fuel vapor. The fuel vapor passage  14  communicates the canister  20  with a space inside the fuel tank T. The purge passage  16  communicates between the canister  20  and an intake air passage (not shown) of the engine. The atmospheric passage  18  communicates between inside and outside of the canister  20 . 
         [0029]    As shown in  FIG. 1 , the fuel vapor passage  14  is connected to a tank port  21  of the canister  20 . The purge passage  16  is connected to a purge port  22  of the canister  20 . An electromagnetic valve  16   v  for opening and closing the purge passage  16  is provided in the midway of the purge passage  16 . An atmospheric passage  18  is connected to an atmospheric port  23  of the canister  20  via a pump unit  30 . The pump unit  30  is used for a leak check of the fuel vapor from the fuel vapor processing apparatus  10 . 
         [0030]    When the engine is not operating, the fuel vapor within the fuel tank T is introduced into the canister  20  via the fuel vapor passage  14  and can be adsorbed by the adsorption material  12 . Because the electromagnetic valve  16   v  of the purge passage  16  is closed when the engine is not operating, the fuel vapor inside the canister  20  does not leak out into the intake air passage of the engine. 
         [0031]    The electromagnetic valve  16   v  opens when the engine is operating and air inside the canister  20  is drawn into the intake air passage via the purge passage  16 . Accordingly, air flows into the canister  20  via the atmospheric passage  18 , the pump unit  30  and the atmospheric port  23 , and then purges the fuel vapor adsorbed by the adsorption material  12 . Thereafter, the purged fuel vapor and air are drawn into the intake air passage of the engine. 
         [0032]    According to this device, the fuel vapor generated inside the fuel tank T can be prevented from leaking into the atmosphere. The leak check of the fuel vapor processing apparatus  10  is performed at a pre-determined timing when the engine is not operating. During the leak check, the pump unit  30  operates to eject the air inside the canister  20  to outside via the atmospheric passage  18 . At that time, the inside pressures of the canister  20 , the fuel vapor passage  14  and the purge chancel  16  become negative. The leak check for the fuel vapor processing apparatus  10  is performed by monitoring the negative pressure inside the canister  20  during a predetermined period of time. 
       &lt;Pump Unit&gt; 
       [0033]    As shown in  FIGS. 5(A) to 5(E) , the pump unit  30  has a pump housing  31 . A pump (not shown) and a motor (not show) to drive the pump are stored inside the pump housing  31 . 
         [0034]    The pump housing  31  is formed to have a substantially prismatic box-shaped configuration. A short communicating pipe  36  for connecting to the atmospheric port  23  of the canister  20  is formed on a bottom surface  31   d  of the pump housing  31  at a substantially central position of the bottom surface  31   d  and projects downwardly therefrom. As shown in  FIGS. 5  (A) and (B), an outlet port  33  extending in the vertical direction (parallel to the axial direction of the short communicating pipe  36 ) is formed at a corner of the pump housing  31 . A connector  35  is formed on an upper surface  31   u  of the pump housing  31  and extends upward therefrom. A cable connector (not shown) for the motor can be connected to the connector  35 . 
         [0035]    An outer peripheral surface of the pump housing  31  is constituted with a first peripheral surface  311 , a second peripheral surface  312 , a third peripheral surface  313 , a fourth peripheral surface  314  and a concaved surface  315  formed between the second peripheral surface  312  and the third peripheral surface  313 . The aforementioned outlet port  33  is positioned at a corner between the first peripheral surface  311  and the fourth peripheral surface  314 . 
         [0036]    A pair of vertical protrusions  31   t  extending linearly in the vertical direction respectively are formed on each of the first periphery surface  311 , the third periphery surface  313  and the forth periphery surface  314 . When the pump housing  31  is fitted into the canister  20  as will be explained later, the vertical protrusions  31  can be positioned within a space formed between the inner peripheral surface of an outer wall  200  (explained below) of the canister  20  and the outer peripheral surface of the pomp housing  31 , so that the pump housing  31  can be prevented from shifting moving relative to the canister  20  in the radial direction. As shown in  FIG. 5  (D), an inclined surface  31   k  is formed on the bottom end of the vertical protrusion  31   t  for preventing interference with the outer peripheral surface of the pump housing  31  during the fitting operation. 
         [0037]    As shown in  FIG. 5(D) , a horizontal protrusion  31   y  extending in the horizontal direction is formed on the central portion of the second outer peripheral surface  312  of the pump housing  31 . Similar to the vertical protrusions  31   t , the horizontal protrusion  31   y  can be positioned within the space formed between the inner peripheral surface of the outer wall  200  of the canister  20  and the outer peripheral surface of the pump housing  31  in order to prevent the shifting movement of the pump housing  31 . 
         [0038]    A shelf-shaped engaging step portion  320  is formed on a substantially central portion of each of the second peripheral surface  312  and the fourth peripheral surface  314  of the pump housing  31 . The engaging step portions  320  can engage with engaging openings  222  formed in the outer wall  200  of the canister  20 . As shown in  FIGS. 5(B)-5(E) , each engaging step portion  320  has a flat plate-like main body  324  and a rib portion  325 . The main body  324  projects at right angle from the corresponding outer peripheral surfaces  312  or  414 . The rib portion  325  has a triangular configuration in a side view and supports the main body  324  from its lower side. The protruding distance of the engaging step portions  320  is set to be larger than the protruding distance of the vertical protrusions  31   t  and the horizontal protrusion  31   y.    
       &lt;Outer Wall of Canister&gt; 
       [0039]    The communicating short pipe  36  formed on the pump housing  31  may be inserted into and connected to the atmospheric port  23  (see  FIG. 4  (B)) of the canister  20  so that the pump unit  30  can communicate with the canister  20 . The atmospheric port  23  of the canister  20  serves as a communicating pipe receiver of the canister  20 . The communicating short pipe  36  of the pump housing  31  corresponds to a communicating pipe of the accessory component. 
         [0040]    As shown in  FIGS. 3 and 4(A)  to  4 (D), the outer wall  200  is formed to surround the atmospheric port  23  of the canister  20 . The pump housing  31  is fitted into the outer wall  200  as the communicating short pipe  36  of the pump housing  31  is inserted into and connected to the atmospheric port  23 . As shown in  FIG. 3 , the outer wall  200  has a prismatic tubular shape substantially conforming to a shape in plan view of the pump housing  31 . End surfaces (outer end surfaces in the protruding direction away from the pump housing  31 ) of the vertical protrusions  31   t  and the horizontal protrusion  31   y  of the pump housing  31  contact the inner peripheral surface of the outer wall  200  when the pump housing  31  is fitted into the outer wall  200  of the canister  20 . On the outer wall  200 , a groove-like concave  203  having a circular arc shaped cross section is formed at the corner corresponding to the outlet port  33  of the pump housing  31 . 
         [0041]    As shown in  FIG. 2 , a pair of slit-like cutouts  211  are formed on each of a front wall  210  corresponding to the second outer peripheral surface  312  and a back wall  220  corresponding to the fourth outer peripheral surface  314  of the pump housing  31  and extend from the central position of the top end of each of the walls  210  and  211  in the vertical direction (the downward direction in  FIG. 2 ). More specifically, because of the pair of cutouts  211 , a wall portion  213  located between the cutouts  211  is separated from the other wall portion in the circumferential direction. Because the outer wall  200  of the canister  20  is made of resin, the wall portions  213  are elastically deformable in directions perpendicular to the front wall  210  and the back wall  220 , respectively (directions perpendicular to the sheet surface of  FIG. 2 ). The walls  213  will be hereinafter also called spring plate portions  213 . 
         [0042]    The engaging openings  222  for engaging the engaging step portions  320  of the pump housing  31  are formed at positions proximal to the base ends of the spring plates  213  and each has a substantially square configuration. The engaging openings  222  are positioned to be able to engage the engaging step portions  320  of the pump housing  31  when the pump housing  31  is fitted into the outer wall  200  and the communicating short pipe  36  is inserted into and connected with the atmospheric port  23 . 
       &lt;Assembling Operation of the Pump Unit to the Canister&gt; 
       [0043]    As shown in  FIG. 4  (B), the assembling operation of the pump unit  30  to the canister  20  is performed by fitting the pump unit  30  into the outer wall  200  of the canister  20  while the pump unit  30  being moved in the axial direction of the communicating short pipe  36 . For this operation, the position of the outlet port  33  of the pump unit  30  (the pump housing  31 ) is aligned with the position of the concave  203  of the outer wall  200  of the canister  20 . 
         [0044]    During the fitting process of the pump unit  30 , the inclined surfaces  31   k  of the vertical protrusions  31   t  formed on the outer peripheral surfaces of the pump unit  30  (the pump housing  31 ) may first contact the inner side of the upper end of the outer wall  200  of the canister  20  and may then slide thereon. Due to this, the pump unit  30  can be positioned relative to the outer wall  200  of the canister  20  with respect to a radial direction of the communicating short pipe  36 . As the fitting process of the pump unit  30  further proceeds, end surfaces (outer end surfaces) of the vertical protrusions  31   t  and the horizontal protrusion  31   y  formed on the outer peripheral surface of the pump unit  30  are brought to contact with the inner peripheral surface of the outer wall  200 . Under this condition, the communicating short pipe  36  of the pump unit  30  and the atmospheric port  23  of the canister  20  are held to extend along the same axis. 
         [0045]    Accordingly, it is possible to fit the pump unit  30  into the outer wall  200  of the canister  20  and concurrently to insert the communicating short pipe  36  of the pump unit  30  into the atmospheric port  23  of the canister  20  for connection therewith. 
         [0046]    Further, during the fitting process of the pump unit  30 , the ribs  325  of the engaging step portions  320  of the pump unit  30  push the spring plates  213  of the outer wall  200  of the canister  20  against the elastic force, so that the spring plates  213  are outwardly opened. When the communicating short pipe  36  of the pump unit  30  is inserted into the atmospheric port  23  of the canister  20  by a predetermined depth, the engaging step portions  320  of the pump unit  30  reach to the positions to be opposed to the engaging openings  222  of the spring plate  213  and then the spring plates  213  are returned back to the original positions due to the elastic force. Becuase of this, as shown in  FIGS. 4  (C) and (D), the engaging step portions  320  of the pump unit  30  engage with the peripheral edges of the corresponding engaging openings  222  of the spring plate  213 , and accordingly, the pump unit  30  is fixed to the outer wall  200  of the canister  20 . In this way, the assembling process of the pump unit  30  to the canister  20  is completed. 
         [0047]    The engaging step portions  320  of the pump unit  30  (the pump housing  31 ), the spring plates  213  formed on the outer wall  200  of the canister  20 , and the engaging openings  222  constitute an engaging mechanism. 
       Advantages of the Pump Unit Mounting Device of the Present Embodiment 
       [0048]    According to the pump unit mounting device of the first embodiment, the engagement mechanism (constituted by the engaging step portions  320 , the spring plates  213 , and the engaging openings  222 ) is provided between the outer wall  200  of the canister  20  and the pump housing  31  of the pump unit  30 . As the pump unit  30  (the pump housing  31 ) is fitted into the outer wall  200  of the canister  20  by a predetermined depth, that the engaging mechanism elastically engages the pump unit  30  with the outer wall  200  and fixes the pump unit  30  to the canister  20 . In addition, as the pump unit  30  is fitted into the outer wall  200  of the canister  20  by the predetermined depth, the communicating short pipe  36  is connected to the atmospheric port (a communicating pipe receiver)  23  of the canister  20 . 
         [0049]    In this way, the pump unit  30  may be fixed to the canister  20  by fitting the pump unit  30  into the outer wall  200  of the canister  20  by a predetermined depth, the number of steps required for assembling the pump unit  30  to the canister  20  may be reduced compared to that required for fixing the pump unit  30  to the canister  20  with bolts. Further, because the pump unit  30  is fitted into the outer wall  200  of the canister  20 , the pump unit  30  may be stably fixed to the canister  20  even in the case that the weight of the pump unit  30  is heavy. 
         [0050]    In addition, the outlet port  33  (a projection) extending in the axial direction of the communicating short pipe  36  is formed on the outer peripheral surface of the pump unit  30 , and the concave  203  is formed on the inner periphery surface of the outer wall  200  of the canister  20  at a location corresponding to the outlet port  33  of the pump unit  30 . Therefore, by fitting the pump unit  30  into the outer wall  200  of the canister  20  in such a way that the outlet port  33  of the pump unit  30  is aligned with the concave portion  203  of the outer wall  200  of the canister  20 , it is possible to eliminate improper assembling. 
         [0051]    Further, a plural number of protrusions  31   t  and  31   y  are formed on the outer peripheral surface of the pump unit  30  on opposite sides with respect to the center of the pump unit  30  and can contact the inner peripheral surface of the outer wall  200  of the canister  20 . Accordingly, the protrusions  31   t  and  31   y  can prevent potential shifting movement of the pump unit  30  relative the outer wall  200  of the canister  20 . 
       &lt;Possible Modifications&gt; 
       [0052]    The present invention may not be limited to the above-described embodiment but may be modified in various ways. For example, the pump unit  30  is described as an example of accessory components of the canister  20  in the present embodiment. However, it is also possible to apply the present disclosure to a mechanism for mounting the electromagnetic valve  16   v  of the purge passage  16  to the purge port  22  of the canister  20 . In such a case, the purge port  22  of the canister  20  corresponds to the communicating pipe receiver and the outer wall  200  is formed to surround the purge port  22 . The present disclosure may also be applied to a mechanism for mounting an air filer to a corresponding port of the canister  20 . 
         [0053]    In the above embodiment, the engaging step portions  320  are formed on the pump unit  30 , and the spring plates  213  and the engagement openings  222  are formed on the outer wall  200  of the canister  20 . However, it is possible to form the spring plates  213  and the engagement openings  222  on the pump unit  30 , and to form the engaging step portions  320  on the outer wall  200  of the canister  20 . 
         [0054]    Further, the vertical protrusions  31   t  and horizontal protrusion  31   y  are formed on the outer peripheral surface of the pump unit  30  in the above embodiment. However, the horizontal protrusion  31   y  may be replaced with vertical protrusion  31   t  so that all the protrusions are provided as the vertical protrusions  31   t . Alternatively, the vertical protrusions  31   t  may be replaced with horizontal protrusions  31   y  so that all the protrusions are provided as the horizontal protrusions  31   y.