Patent Publication Number: US-11655783-B2

Title: Air cleaner for vehicles

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0140039, filed on Oct. 27, 2020, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The present disclosure relates to an air cleaner for vehicles. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     An engine of a vehicle requires air to burn fuel, and receives air necessary at the time of combustion from outside the vehicle through an intake system. The intake system is configured to supply air to a combustion chamber of the engine to maintain engine performance, and includes an air cleaner configured to remove foreign matter from air. 
     In the intake system of the vehicle engine, outside air introduced through an intake duct is filtered by the air cleaner to form clean air, and the clean air is supplied to the engine through an intake hose. A filter configured to allow the outside air to pass therethrough to remove foreign matter from the air is provided in the air cleaner. 
     In general, an air cleaner for vehicles may be classified as a vertical flow type air cleaner, in which air introduced into a case passes through a filter from below to above or from above to below, or a horizontal flow type air cleaner, in which air introduced into a case passes through a filter from inside to outside or from outside to inside. 
     However, the height and volume of a conventional air cleaner are large to provide a sufficient flow channel of air passing through a filter in a case. In addition, the filter is stably supported in the case of the air cleaner. Furthermore, a body and a cover forming the case is be stably supported and stiffness thereof must be provided. We have discovered that reducing the height and volume of the air cleaner and improving for maintaining a rigid support structure and securing stiffness are desired. 
     In addition, it is desirable to further simplify the structure for reduction in the number of parts, cost, and weight. In particular, for a hybrid electric vehicle, an improved structure in which the height of the filter is reducible while the filter has sufficient area and filtration performance is desired. 
     The above information disclosed in this Background section is provided only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. 
     SUMMARY 
     The present disclosure provides an air cleaner configured such that a filter is stably supported in a case and a filter support structure is simplified to remove undesired parts, whereby it is possible to reduce cost and weight and to reduce the height of the filter. 
     The present disclosure provides an air cleaner for vehicles, the air cleaner including: a case including an inlet, through which outside air is introduced, and an outlet, through which filtered air is discharged; and a filter installed in an inner space of the case, configured to filter the outside air introduced through the inlet, and including a filtration member, wherein the filtration member is formed in an “n” shape open downwards and is configured to allow the outside air to pass therethrough in a downward direction and in a lateral direction. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which: 
         FIG.  1    is a perspective view showing an air cleaner according to one form of the present disclosure and an intake system; 
         FIG.  2    is a perspective view showing inner construction of the air cleaner according to one form of the present disclosure; 
         FIGS.  3  and  4    are perspective views showing a body of the air cleaner according to one form of the present disclosure; 
         FIG.  5    is a perspective view showing the air cleaner according to one form of the present disclosure in the state in which a first cover is removed therefrom; 
         FIG.  6    is an enlarged perspective view of part B of  FIG.  5   ; 
         FIG.  7    is a sectional view of the air cleaner according to one form of the present disclosure taken along line A-A of  FIG.  1   ; 
         FIG.  8    is a perspective view showing the disposition state of a rigidity reinforcement rib formed on the inner surface of the first cover in the air cleaner according to one form of the present disclosure; 
         FIG.  9    is a sectional view taken along line C-C of  FIG.  8   ; 
         FIG.  10    is a perspective view illustrating an air guide formed on an outlet side of an enlarged pipe portion in the air cleaner according to one form of the present disclosure; 
         FIG.  11    is a perspective view showing a filter in the air cleaner according to one form of the present disclosure; 
         FIG.  12    is a sectional view taken along line D-D of  FIG.  11   ; 
         FIG.  13    is an enlarged perspective view showing the state in which opposite ends of a filtration member are coupled to coupling plates of a filter frame in one form of the present disclosure; 
         FIGS.  14 ,  15  and  16    are sectional views showing the state in which the filter is coupled inside a case of the air cleaner in one form of the present disclosure; and 
         FIGS.  17  and  18    are views showing the direction of air introduced into a filter side and the direction of air discharged from the filter side in the air cleaner according to one form of the present disclosure. 
     
    
    
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
     It will be understood that, although the terms “first”, “second”, etc. may be used herein to describe various elements, corresponding elements should not be understood as being limited by these terms, which are used only to distinguish one element from another. For example, within the scope defined by the present disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. 
     It will be understood that, when a component is referred to as being “connected to” or “coupled to” another component, it may be directly connected to or coupled to the other component, or intervening components may be present. In contrast, when a component is referred to as being “directly connected to” or “directly coupled to” another component, there are no intervening components present. Other terms that describe the relationship between components, such as “between” and “directly between” or “adjacent to” and “directly adjacent to”, must be interpreted in the same manner. 
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. The terms used in this specification are provided only to explain specific forms, but are not intended to restrict the present disclosure. A singular representation may include a plural representation unless it represents a definitely different meaning from the context. It will be further understood that the terms “comprises”, “comprising” and the like, when used in this specification, specify the presence of stated components, steps, operations, and/or elements, but do not preclude the presence or addition of one or more other components, steps, operations, and/or elements. 
     Hereinafter, various forms of the present disclosure will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a perspective view showing an air cleaner  100  according to one form of the present disclosure and an intake system, and  FIG.  2    is a perspective view showing inner construction of the air cleaner according to one form of the present disclosure. In addition,  FIGS.  3  and  4    are perspective views showing a body of the air cleaner according to one form of the present disclosure. 
     In addition,  FIG.  5    is a perspective view showing the air cleaner according to one form of the present disclosure in the state in which a first cover is removed therefrom, and  FIG.  6    is an enlarged perspective view of part B of  FIG.  5   . In addition,  FIG.  7    is a sectional view of the air cleaner  100  according to one form of the present disclosure taken along line A-A of  FIG.  1   . 
     The air cleaner  100  according to one form of the present disclosure is an air cleaner usable in an intake system of a hybrid electric vehicle (HEV). 
     As shown, the air cleaner  100  according to one form of the present disclosure includes a case  101  having an inner space that is hermetically sealed and a filter  150  mounted in the case  101 . The case  101  includes a body  110  and a cover  130 ,  140  assembled to the upper side of the body  110 . Here, the cover includes a first cover  130  and a second cover  140 . 
     The body  110  is provided at one side and the other side thereof with an inlet  111 , through which outside air is introduced, and an outlet  112 , through which filtered air (clean air) is discharged, respectively. An intake duct  210  configured to guide outside air to the air cleaner  100  is connected to the inlet  111  of the body  110 . An intake hose  220  configured to guide air passing through the air cleaner  100  to an electronic throttle controller (ETC) is installed at the outlet  112  of the body  110 . An airflow sensor (AFS) (not shown) may be installed in the intake hose  220 . 
     The inner space of the body  110  is partitioned into three parts. Although the inner spaces of the three parts are divided from each other, the three parts are connected to each other and form the entirety of the body  110 . One of the three parts is a filter receiving portion  102  configured to receive the filter  150 , another part connected to the filter receiving portion  102  is a part forming an enlarged pipe portion  103 , and another part connected to the enlarged pipe portion  103  is a part forming a resonator  104 . In the state in which the first cover  130  and the second cover  140  are assembled to the upper side of the body  110  to hermetically seal the inner spaces, therefore, the filter receiving portion  102 , the enlarged pipe portion  103 , and the resonator  104  are integrally connected to each other in the case  101  of the air cleaner  100 . 
     In the case  101  of the air cleaner  100 , the outlet  112  may be formed in the body  110 , and is located at one side of the part forming the enlarged pipe portion  103  of the body  110 . In the state in which the filter  150  is received in the filter receiving portion  102 , therefore, air guided through the intake duct  210  is introduced into the filter receiving portion  102  through the inlet  111  of the body  110  and passes through the filter  150 . During passage through the filter  150 , foreign matter is removed from the air. The air from which foreign matter has been removed (clean air) passes through the enlarged pipe portion  103  and is discharged to the intake hose  220  through the outlet  112 . 
     That is, in the case  101 , the inner space of the filter receiving portion  102  is a dirty side, and the inner space of the enlarged pipe portion  103  is a clean side. The dirty side is a space in which air before filtration, i.e. outside air, is introduced and flows towards the filter  150 , and the clean side is a space through which filtered air, i.e. air from which foreign matter has been removed by the filter  150  (clean air), passes. 
     The first cover  130  and the second cover  140  are assembled to the upper side of the body  110 , and form the filter receiving portion  102 , the enlarged pipe portion  103 , and the resonator  104 , which have a hermetically sealed structure, in the state of being assembled to the body  110 . At this time, the first cover  130  is assembled to the body  110  to cover the filter receiving portion  102  and the upper side of the filter  150  received in the filter receiving portion  102 , and the second cover  140  is assembled to the body  110  to cover the inner spaces of the enlarged pipe portion  103  and the resonator  104 . 
     The enlarged pipe portion  103  is a part forming the clean side, and is a space through which air filtered by the filter  150  passes. The enlarged pipe portion  103  performs the function of a surge tank in a conventional intake system  1 , reduces the speed of air introduced into the air cleaner  100  and at the same time reduces flow resistance. Consequently, the enlarged pipe portion  103  serves to stabilize a flow channel of air introduced into an engine, thereby improving engine performance and reducing noise. 
     The resonator  104  may be a Helmholtz type resonator. The resonator  104  serves to reduce noise together with the enlarged pipe portion  103 , and serves to further reduce noise in addition to noise reduction by the enlarged pipe portion  103 . That is, the resonator  104  reduces a specific-frequency component of the noise that has not been removed by the enlarged pipe portion  103 , thereby reducing engine wavelengths and thus improving NVH performance. 
     In  FIGS.  3  and  5   , reference symbol  120  indicates a boundary portion configured to partition the inner space of the enlarged pipe portion  103  and the inner space of the resonator  104  from each other in the body  110 . The boundary portion  120  is formed on the inner bottom surface of the body  110  along a boundary part between the enlarged pipe portion  103  and the resonator  104  in a projecting fashion. 
     In one form of the present disclosure, the first cover  130  and the second cover  140  assembled to the upper side of the body  110  also serve as an engine cover, although the first cover  130  and the second cover  140  form a cover of the air cleaner  100 . When assembled to the body  110 , the second cover  140  may be fixed to a body part forming the enlarged pipe portion  103  by fusion. In  FIG.  3   , reference symbol  118  indicates a support protrusion  118  fused to a region of the body part forming the enlarged pipe portion  103  corresponding to the lower surface of the second cover  140 . The support protrusion  118  is formed at the enlarged pipe portion  103  so as to project upwards from the inner bottom surface of the body  110 . 
     The support protrusion  118  is fused to the lower surface of the second cover  140  assembled to the upper side of the body  110  to fix the second cover  140  to the body  110 . In addition, the support protrusion  118  serves to support the second cover  140  at the body  110  and at the same time serves to reinforce rigidity between the body  110  and the second cover  140 . In one form of the present disclosure, a plurality of support protrusions  118  may be formed on the inner bottom surface of the body  110 , and the plurality of support protrusions  118  stably supports the second cover and reinforces rigidity in the state of being fused to the second cover  140 . 
     When the body  110  and the first cover  130  are coupled to each other, a sealing member  113  may be interposed in a joint between the body  110  and the first cover  130  in a compressed state. That is, when the body  110  and the first cover  130  are coupled to each other, a peripheral part of the filter receiving portion of the body  110  and a peripheral part of the first cover  130  may be joined to each other, and a sealing member  113  made of a rubber material may be interposed between the peripheral parts in a compressed state. The sealing member  113  serves to maintain hermetic sealing such that no air leaks from between the peripheral parts and to inhibit engine noise from being discharged from between the peripheral parts. 
     The inner structure of the body will be described in more detail with reference to  FIGS.  3  to  7   . First, the support rib  115 , which supports the filter  150  from below, is formed on one side of the inner bottom surface of the body  110  in a projecting fashion. The support rib  115  serves to support the filter  150  in the filter receiving portion  102 , and inhibits the filter  150  from being pushed by air introduced through the inlet  111 . 
     In addition, a fixing protrusion  114  configured to support and fix one end of the filter  150  is formed on the other side of the inner bottom surface of the body  110  in a projecting fashion. In one form of the present disclosure, a plurality of fixing protrusions  114  may be formed on the inner bottom surface of the body  110  so as to be disposed at predetermined intervals. 
     In addition, a seating recess  114   a , in which one end of the filter  150  is supported in a seated state, is formed in each fixing protrusion  114 . At this time, the seating recess  114   a  of each fixing protrusion  114  may be formed so as to have an L-shaped sectional shape. In the case in which one end of the filter  150  is seated in the seating recess  114   a  having the above-described shape, the filter  150  is caught by the inner surface of the seating recess  114   a , whereby the filter is inhibited from being pushed. 
     Referring to  FIG.  7   , the first cover  130  is assembled to the body  110  so as to cover the filter receiving portion and the filter  150  received in the filter receiving portion from above in the inner space of the body  110 , and the peripheral part of the first cover  130  and the peripheral part of the filter receiving portion of the body  110  corresponding thereto are joined to each other in the state in which the sealing member  113  is compressed. In addition, the air cleaner  100  according to one form of the present disclosure is disposed obliquely in an engine compartment of a vehicle, as shown, and the filter  150  received in the case  101  of the air cleaner  100  is also disposed obliquely. 
     At this time, the fixing protrusion  114  is formed on the inner bottom surface of the body  110  so as to project upwards, and the seating recess  114   a , the sectional shape of which is approximately L-shaped, is formed in the fixing protrusion  114 . One end of the filter  150 , specifically the lower end of a fixing member  151  (see  FIG.  14   ) located at one end of the filter  150 , is supported in the state of being seated inside the seating recess  114   a . Consequently, in the state in which the fixing member  151  of the filter  150  is supported on the inner surface of the seating recess  114   a  in a joined state, whereby the entirety of the filter  150  may be inhibited from being pushed downwards (in a leftward direction in the figure). In addition, the upper end of the fixing member  151  located at one end of the filter  150  is supported in the state of being caught by the inside of a catching jaw portion  132  (see  FIGS.  7  and  14   ) formed on the lower surface of the first cover  130 , whereby the filter  150  may be stably supported by the catching jaw portion  132  of the first cover  130  and the fixing protrusion  114  of the body  110  without being pushed downwards. 
     Meanwhile, a wall portion  116   a  configured to partition the inner space of the filter receiving portion  102  and the inner space of the enlarged pipe portion  103  from each other is formed on the inner bottom surface of the body  110  along a boundary part between the inner spaces in a projecting fashion. At this time, the peripheral part of the second cover  140  is joined to the peripheral part of the enlarged pipe portion, the peripheral part of the resonator, and the upper end surface of the wall portion  116   a  of the body  110 . As a result, the second cover  140  may be assembled so as to cover the inner spaces of the enlarged pipe portion  103  and the resonator  104  from above, and the inner spaces of the enlarged pipe portion  103  and the resonator  104  may be hermetically sealed by the second cover  140 . 
     In addition, a support portion  116   b  may be formed at the surface of the wall portion  116   a  of the body  110  that abuts the inner space of the filter receiving portion  102  so as to extend long along the wall portion in a lateral direction in a projecting fashion, and the support portion  116   b  may be formed at the surface of the wall portion  116   a  in the shape of a plate having a predetermined width. The support portion  116   b  is a portion of the peripheral part of the body to which the peripheral part of the first cover  130  is joined, and the peripheral part of the first cover  130  is joined to the upper surface of the support portion  116   b  in the state in which the sealing member  113  is compressed. 
     In addition, a coupling portion  116   c  is formed at the surface of the wall portion  116   a  of the body  110  that abuts the inner space of the filter receiving portion  102  so as to be located at the lower side of the support portion  116   b  in a projecting fashion, and a discharge port  153  (see  FIG.  11   ) of the filter  150  is coupled to the coupling portion  116   c . The discharge port  153  of the filter  150  is a part forming an outlet, through which air filtered by the filter (clean air) is discharged. The coupling portion  116   c  of the body  110  may be formed on the surface of the wall portion  116   a  so as to project by a width greater than the width of the support portion  116   b  at the upper side thereof, and may be formed in the shape of a quadrangular pipe extending long along the wall portion  116   a  in a leftward-rightward direction. An inner path  117  of the coupling portion  116   c  is formed through the wall portion  116   a  between the filter receiving portion  102  and the enlarged pipe portion  103 . When filtered air (clean air) is discharged through the discharge port  153  of the filter  150 , the filtered air moves to the enlarged pipe portion  103  along the inner path  117  of the coupling portion  116   c.    
     A partition wall  116   d  configured to partition the inner path  117  of the coupling portion may be formed at the inner surface of the coupling portion  116   c . The partition wall  116   d  may be formed so as to vertically interconnect the upper surface and the lower surface of the coupling portion  116   c , as shown in  FIG.  6   . At this time, a plurality of partition walls  116   d  may be formed along the coupling portion  116   c  so as to be disposed at predetermined intervals. Consequently, the plurality of partition walls  116   d  may perform the function of a rigidity reinforcement structure configured to inhibit deformation of the coupling portion  116   c  while maintaining the distance between the upper surface and the lower surface of the coupling portion  116   c.    
     The coupling portion  116   c  has a shape projecting by a predetermined width P more than the support portion  116   b  (see  FIG.  3   ), to which the sealing member  113  is coupled, as shown in  FIG.  6   . Consequently, a portion of the coupling portion  116   c  projecting by the width P more than the support portion  116   b  may be inserted inside the discharge port  153  (see  FIG.  11   ) of the filter  150  so as to be coupled thereto. At this time, the inner surface of the discharge port  153  and the outer surface of the coupling portion  116   c  are coupled to each other so as to overlap each other in a joined state. Since the discharge port  153  of the filter  150  is coupled to the coupling portion  116  projecting from the wall portion  116   a  of the body  110 , as described above, the coupling portion  116  of the body  110  also serves to support the discharge port  153  of the filter  150 . 
     Referring to  FIG.  7   , the fixing member  151  (see  FIG.  14   ), located at one end of the filter  150 , is supported by the catching jaw portion  132  of the first cover  130  and the fixing protrusion  114  of the body  110 , and at the same time a fixing member  152  (see  FIG.  14   ), located at the other end of the filter  150 , is supported in the state of being coupled to the coupling portion  116  of the body  110 . In addition, the inner path of the coupling portion allows the space inside the filter and the enlarged pipe portion to communicate with each other in the state in which the coupling portion is inserted into the discharge port  153  (see  FIG.  11   ) of the filter  150  formed at the fixing member  152 . In addition, the filter  150  is also supported by the support rib  115 , formed on the inner bottom surface of the body  110 . 
       FIG.  8    is a perspective view showing the disposition state of a rigidity reinforcement rib  131  formed on the inner surface of the first cover  130 , i.e. the lower surface of the first cover  130 , in the air cleaner  100  according to one form of the present disclosure. In one form of the present disclosure, the rigidity reinforcement rib  131  may be formed on the lower surface of the first cover  130 . In  FIG.  8   , the first cover  130  is shown in a transparent state to show the disposition state of the rigidity reinforcement rib  131 . 
       FIG.  9    is a sectional view taken along line C-C of  FIG.  8   . Referring to this, it can be seen that the rigidity reinforcement rib  131  is integrally formed on the lower surface of the first cover  130 . The rigidity reinforcement rib  131  may be formed on the lower surface of the first cover  130  so as to extend long in the leftward-rightward direction. At this time, the rigidity reinforcement rib  131  may be formed so as to interconnect left and right side surfaces of the first cover  130  in the form of a bridge. Consequently, the rigidity of the first cover  130  may be reinforced by the rigidity reinforcement rib  131 , whereby deformation of the first cover  130  may be inhibited. In addition, the rigidity reinforcement rib  131  of the first cover  130  may also serve to push the filter  150  received in the filter receiving portion  102  of the case  101  downwards. Consequently, a filtration member  159  of the filter  150  may be inhibited from moving upwards and downwards. 
     In  FIG.  5   , reference symbol  141  indicates a hydrocarbon trap (HC-trap)  141  installed at the inner surface of the second cover  140 , i.e. the lower surface of the second cover  140 . As described above, the hydrocarbon trap  141  may be installed in the case  101  of the air cleaner  100 . The hydrocarbon trap  141  may be installed to adsorb and collect hydrocarbon, which forms an evaporation gas component of fuel, in the case  101  of the air cleaner  100 , and may be fixed to the lower surface of the second cover  140  by fusion, as shown in  FIG.  5   . 
     In the case in which the vehicle is stopped and the engine is off, hydrocarbon, discharged from a cylinder of the engine through an intake port may move to the air cleaner  100  through the intake hose  220 . For this reason, the hydrocarbon trap  141  is installed in the case  101  of the air cleaner  100  to adsorb and collect hydrocarbon discharged from the cylinder of the engine. 
     When the engine is started, hydrocarbon collected by the hydrocarbon trap  141  is introduced into the engine together with air introduced into the air cleaner  100 , and is burned in the cylinder. In one form of the present disclosure, the hydrocarbon trap  141  may be attached to the lower surface of the second cover  140  so as to be located at the upper side of the inner space of the enlarged pipe portion  103 . 
     In  FIG.  8   , reference symbol  113   a  indicates an insertion protrusion formed on the sealing member  113 . The insertion protrusion  113   a  is configured to be inserted into a recess (not shown) formed in the peripheral part of the first cover  130  so as to be coupled thereto. In one form of the present disclosure, a plurality of insertion protrusions  113   a  may be formed so as to be disposed in a longitudinal direction of the sealing member  113  at predetermined intervals. At this time, the plurality of insertion protrusions  113   a  may be formed on the inner edge of the sealing member  113  or on the outer edge of the sealing member  113 . Consequently, the sealing member  113  may be coupled to the peripheral part of the first cover  130  such that each insertion protrusion  113   a  is inserted into a corresponding recess of the first cover  130 , and the first cover  130  may be assembled to the body  110  in the state in which the sealing member  113  is coupled thereto. 
     Meanwhile, air filtered by the filter  150  moves from the enlarged pipe portion  103 , which is the clean side, toward the outlet  112 . An air guide  119  configured to guide air passing through the inner space of the enlarged pipe portion  103  to the outlet  112  is formed at the inner bottom surface of the body  110  extending from the inner space of the enlarged pipe portion  103  to an outlet side bottom surface, i.e. the outlet  112 . 
       FIG.  10    is a perspective view illustrating the air guide  119  formed on the outlet side of the enlarged pipe portion in the air cleaner according to one form of the present disclosure. In one form of the present disclosure, a plurality of air guides  119  may be formed at the bottom surface of the body  110  so as to be disposed at predetermined intervals. Referring to  FIG.  10   , it can be seen that air passing through the inner space of the enlarged pipe portion  103  moves to the outlet  112  of the air cleaner  100  along paths between the air guides  119  (see arrows). As the air guides  119  are formed at the outlet side of the enlarged pipe portion  103 , as described above, air may naturally move toward the outlet  112  while being guided by the air guides  119 , whereby a cavitation phenomenon may be inhibited. 
     In addition, a leading pipe  105  may be installed at the outlet  112  of the air cleaner  100  together with the air guides  119 . Consequently, air guided by the air guides  119  passes through the leading pipe  105  and then moves toward the outlet  112 . The leading pipe  105  serves to lead air to the outlet  112  while gathering the air such that air passing through the air guides  119  can naturally move to the outlet  112 . 
     In one form of the present disclosure, the leading pipe  105  may be configured in a cylindrical shape, and the rear end of the leading pipe  105  may be fixed and assembled to the body  110  in state of being inserted inside the outlet  112  of the air cleaner. The front end of the leading pipe  105  may have a larger inner diameter than the rear end of the leading pipe  105 , and preferably has an inner diameter gradually decreased toward the rear end of the leading pipe  105 . Consequently, air passing through the air guides  119  may be gathered inside the front end of the leading pipe  105  and may then be led to the outlet  112 . As a result, air passing from the outlet side of the enlarged pipe portion  103  along the air guides  119  and the leading pipe  105  may be discharged through the outlet  112  of the air cleaner  100  and may then pass through the intake hose  220 , in which the airflow sensor (AFS) is installed. 
     Next, the filter will be described in detail. 
       FIG.  11    is a perspective view showing the filter  150  in the air cleaner according to one form of the present disclosure, and  FIG.  12    is a sectional view taken along line D-D of  FIG.  11   . As shown in  FIG.  7   , the filter  150  is received in the filter receiving portion  102  of the air cleaner  100  (the case  101 ). In one form of the present disclosure, the filter  150  may have a filtration member  159  disposed in a “∩” shape. 
     The “∩”-shaped filtration member  159  is disposed so as to be open downwards from the filter receiving portion  102  of the case  101 . Air introduced into the upper side of the filter  150  in the inner space of the filter receiving portion  102  through the inlet  111  of the case  101  in the air cleaner  100  passes through the filtration member  159  in a downward direction and moves into the filter  150 . In addition, air introduced to the lateral side of the filter  150  in the inner space of the filter receiving portion  102  passes through the filtration member  159  in a lateral direction and moves into the filter  150 . While passing through the filtration member  159 , as described above, foreign matter is removed from the air, and then the air is discharged to the enlarged pipe portion  103  (see the arrow in  FIG.  2   ) 
     Here, in the inner space of the filter receiving portion  102 , the space outside the filter  150  becomes a dirty side space (primary space) into which outside air is introduced, and the space inside the filter  150  becomes a clean side space (secondary space in which air passing through the filtration member  159  (clean air) flows. 
     In addition, air moving inside the filter through the filtration member  159  is discharged through the discharge port  153  formed in the fixing member  152  located at one end of the filter  150 . The discharge port  153  is coupled to the coupling portion  116   c  formed at the wall portion  116   a  of the body  110  (the boundary part between the filter receiving portion and the enlarged pipe portion). Consequently, air moving inside the filter  150  is discharged through the discharge port  153 , passes through the inner path  117  of the coupling portion  116   c , and is introduced into the enlarged pipe portion  103 , which is a clean side. 
     In one form of the present disclosure, the filter  150  may include a filter frame  154 , a first fixing member  151 , a second fixing member  152 , and a filtration member  159 . Here, the first fixing member  151  and the second fixing member  152  are coupled to opposite side ends of the filter frame  154 . The discharge port  153 , which has an approximately quadrangular shape, is formed through the second fixing member  152 . 
     In addition, the lower end of the first fixing member  151  is supported in the state of being seated in the seating recess  114   a  of the fixing protrusion  114  formed at the body  110 , and the discharge port  153  of the second fixing member  152  is inserted outside the coupling portion  116   c  of the wall portion  116   a  so as to be coupled and fixed thereto. In addition, a lower plate  155   a  of the filter frame  154  is supported in the state of being seated on the support rib  115  of the body  110 . 
     The filter frame  154  and the filtration member  159  are located between the first fixing member  151  and the second fixing member  152 . The filtration member  159  is coupled to the filter frame  154 . At this time, the filter frame  154  serves to maintain the shape of the filtration member  159  while fixing and supporting the filtration member  159 . In one form of the present disclosure, each of the first fixing member  151  and the second fixing member  152  may be manufactured by foaming polyurethane (PU). In the case in which each of the first fixing member  151  and the second fixing member  152  is made of polyurethane, which is elastic, as described above, the first fixing member  151  and the second fixing member  152  may perform the damping function of an insulator in a filter of a conventional air cleaner. 
     The filter frame  154  includes a lower plate  155   a  installed at the bottom surface of the case  101  (the bottom surface of the body) so as to be supported via the support rib  115  and a lattice type rod structural member installed at the upper side of the lower plate  155   a  so as to be disposed in a “∩” shape. In this construction, the lower plate  155   a  of the filter frame  154  is supported in the state of being seated on the support rib  115  of the body  110 . In addition, the lattice type rod structural member of the filter frame  154  includes a transverse rod  155   c  and a longitudinal rod  155   d . The transverse rod  155   c  and the longitudinal rod  155   d  are disposed at the upper side of the lower plate  155   a  so as to form a lattice type structure. Consequently, the upper part of the filter frame  154  has a lattice type structure. 
     Among the rods forming the lattice type structure, a plurality of transverse rods  155   c  is disposed in a direction parallel to the first fixing member  151  and the second fixing member  152 , and a plurality of longitudinal rods  155   d  is disposed so as to interconnect the first fixing member  151  and the second fixing member  152 . Opposite ends of each transverse rod  155   c  are bent downwards, and opposite ends of each longitudinal rod  155   d  extend downwards so as to be connected to the lower plate  155   a.    
     In this construction, the filter frame  154  and the filtration member  159  are located between the first fixing member  151  and the second fixing member  152 , and the filtration member  159  is coupled to the upper sides of the transverse rods  155   c  and the longitudinal rods  155   d  disposed in the lattice type structure. The filtration member  159  of the filter  150  is disposed in an inverted “U” shape, i.e. a “∩” shape. 
     The filtration member  159  may be made of non-woven fabric, and may have a three-layered structure including a bulky layer, an intermediate layer, and a dense layer. At this time, the dense layer is located in a direction toward the clean side, and the bulky layer is located in a direction toward the dirty side. The filtration member  159  is coupled to the upper side of the filter frame  154 , and is inhibited from being suctioned inside by the filter frame  154  located at the lower side thereof. 
     In addition, the filtration member  159  is configured in a bellows structure folded in a zigzag fashion, as shown in  FIG.  12   . Opposite ends of the filtration member  159  are coupled to the lower plate  155   a  of the filter frame  154 . At this time, coupling plates  156   b  configured to extend in a lateral direction are formed at opposite ends of the lower plate  155   a , and the opposite ends of the filtration member  159  are fixedly coupled to the lower surfaces of the coupling plates  156   b.    
       FIG.  13    is an enlarged perspective view showing the state in which the opposite ends of the filtration member  159  are coupled to the coupling plates  156  of the filter frame  154  in one form of the present disclosure. As illustrated in  FIGS.  12  and  13   , the opposite ends of the filtration member  159  are fixed to the lower surfaces of the coupling plates  156   b  of the filter frame  154  by adhesion. At this time, each end of the filtration member  159  may be fixed to the lower surface of a corresponding one of the coupling plates  156   b  by fusion. 
     In one form of the present disclosure, a guide portion  155   e  may be formed on the lower surface of the lower plate  155   a  in a projection fashion such that a predetermined gap is defined between the lower surface of the lower plate  155   a  and the lower surface of each coupling plate  156   b . Ultrasonic fusion may be performed in the state in which the end of the filtration member  159  is inserted between the coupling plate  156   b  and the guide portion  155   e . At this time, the guide portion  155   e  may be formed so as to form a “[”-shaped sectional shape together with the coupling plate  156   b.    
     In the lattice type rod structural member of the filter frame  154 , a support stand  155   b  configured to support the entire lattice type rod structural member, including the transverse rods  155   c , at the lower plate  155   a  may be formed between at least some of the transverse rods  155   c  and the lower plate  155   a . The support stand  155   b  may be formed so as to interconnect the transverse rods  155   c  and the lower plate  155   a , and also serves as a partition wall configured to partition the space inside the filter between the filtration member  159  and the lower plate  155   a.    
     A coupling protrusion  156   a  may be formed on the upper surfaces of at least some of the transverse rods  155   c  so as to project upwards. The coupling protrusion  156   a  may be formed on a plurality of transverse rods  155   c . A plurality of coupling protrusions  156   a  is inserted inside the folded part of the filtration member  159  at each position so as to be coupled thereto. Since each coupling protrusion  156   a  is inserted inside the folded part of the filtration member  159  so as to be coupled thereto, as described above, the shape of the filtration member  159  is maintained by the coupling protrusions  156   a.    
     Meanwhile, the state in which the filter  150  is installed in the case  101  of the air cleaner  100  will be described.  FIGS.  14 ,  15  and  16    are sectional views showing the state in which the filter  150  is coupled inside the case  101  of the air cleaner  100  in one form of the present disclosure, wherein  FIG.  15    is an enlarged sectional view of part E of  FIG.  14    and  FIG.  16    is an enlarged sectional view of part F of  FIG.  14   . 
     As shown, the first cover  130  is coupled to the body  110  so as to cover the upper side of the filter  150  received in the filter receiving portion  102  of the case  101 , and the sealing member  113  is interposed in the joint between the first cover  130  and the body  110  in a compressed state, as previously described. In addition, the lower end of the first fixing member  151  of the filter  140  is supported in the state of being seated in the seating recess  114   a  of the fixing protrusion  114  formed on the inner bottom surface of the body  110 . At this time, the upper end of the first fixing member is supported in the state of being caught by the catching jaw portion  132  formed at the lower surface of the first cover  130  (see  FIG.  15   ). 
     The upper end of the fixing member  151  located at one end of the filter  150  is supported in the state of being caught by the catching jaw portion  132  of the first cover  130 , as described above, and at the same time the lower end of the first fixing member  151  is supported in the state of being seated in the seating recess  114   a  of the body  110 , whereby the filter  150  may be fixed by the catching jaw portion  132  and the seating recess  114   a  so as not to be pushed downwards. In addition, the filter frame  154  of the filter  150  is supported by the support rib  115  formed on the inner bottom surface of the body  110 . 
     In addition, a bent portion  133  having a bent section and configured to perform a catching action in the state of being in tight contact with the outer surface of the second fixing member  152  of the filter  150  is formed at the lower surface of the first cover  130  so as to project downwards. A joining portion  134  configured to be joined to the support portion  116   b  formed at the wall portion  116   a  in the state in which the sealing member  113  is compressed therebetween is formed at the lower end of the bent portion  133 . 
     In addition, referring to  FIG.  16   , the discharge port  153  formed through the second fixing member  152  of the filter  150  is assembled in the state of being fitted outside the coupling portion  116   c  formed at the wall portion  116   a  of the body  110 . As a result, the inner path  117  of the coupling portion  116   c  of the body  110  communicates with the space inside the filter  150 . Since the discharge port  153  formed in the second fixing member  152  of the filter  150  and the coupling portion  116   c  formed at the wall portion  116   a  of the body  110  are coupled to each other in tight contact, as described above, hermetic sealing may be maintained between the space inside the filter  150  and the inner path  117  of the coupling portion  116   c . In  FIG.  16   , reference symbol  116   d  indicates a partition wall configured to partition the inner path  117  of the coupling portion  116   c.    
     In addition, as shown in  FIGS.  14  and  16   , a catching protrusion  135  configured to perform a catching action in the state of being in tight contact with the inner surface of the second fixing member  152  of the filter  150  is formed on the bent portion  133  at the lower surface of the first cover  130  so as to project downwards. The upper end of the second fixing member  152  of the filter  150  is inserted between the bent portion  133  of the first cover  130  and the catching protrusion  135  so as to be coupled thereto. As a result, as can be seen from  FIG.  16   , the second fixing member  152  of the filter  150  is caught by the bent portion  133  of the first cover  130  and the support portion  116   b  in the upward direction (in the leftward direction in the figure) and thus fixed so as not to be pushed upwards. 
     In addition, when the second cover  140  is assembled to the body  110 , the upper end of the second fixing member  152  of the filter  150  is inserted between the bent portion  133  and the catching protrusion  135  so as to be coupled thereto, whereby the second fixing member  152  is fixed so as not to be pushed downwards by the catching protrusion  135  at the opposite side. The catching protrusion  135  is a part configured to perform a catching action in the direction opposite the bent portion  133 . The second fixing member  152  may be securely coupled to the first cover  130  by the catching protrusion  135  and the bent portion  133  of the first cover  130 , whereby the entirety of the filter  150  maintains a complete coupling state without moving in the case  101  of the air cleaner. 
       FIGS.  17  and  18    are views showing the direction of air introduced into the filter side and the direction of air discharged from the filter side in the air cleaner according to one form of the present disclosure. As previously described, air passes through the filtration member  159  in the downward direction from the upper side of the filter  150 , and at the same time passes through the filtration member  159  in the lateral direction from the lateral side of the filter  140 . Air passing through the filtration member  159  (clean air) is discharged through the discharge portion  153  formed in the second fixing member  152  in the space inside the filter. 
     As is apparent from the foregoing, in the air cleaner according to one form of the present disclosure, the filter may be more stably supported in the case through a simple structure, whereby it is possible to provide excellent dynamic stiffness of the air cleaner and reduce noise. In addition, it is possible to remove undesired parts by simplifying the filter support structure, whereby it is possible to reduce cost and weight and to reduce the height of the filter. 
     It will be apparent to a person of ordinary skill in the art that the present disclosure described above is not limited to the above forms and the accompanying drawings and that various substitutions, modifications, and variations can be made without departing from the technical idea of the present disclosure.