Abstract:
A waterproof device for a drum brake can prevent noise and malfunction of a brake by stopping water from flowing into the drum brake. The waterproof device for a drum brake can minimize not only foreign substances, but also water flowing into a drum, by improving the mounting structure of a dust cover that is mounted at the drum inlet of a drum brake in a new structure that is mounted hermetically and watertightly along the inner edge of a drum by buoyancy or pressure due to water when passing a puddle or a wheel washer.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority of Korean Patent Application Number 10-2013-0140825 filed Nov. 19, 2013, the entire contents of which application is incorporated herein for all purposes by this reference. 
       BACKGROUND OF INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to a waterproof device for a drum brake, and more particularly to a waterproof device for a drum brake which can prevent noise and malfunction of a brake by stopping water from flowing into the drum brake. 
         [0004]    2. Description of Related Art 
         [0005]    Large-sized commercial vehicles used in for construction sites or unpaved roads are supposed to have their wheels washed (wheels and tires washed) before starting, in order to observe the rules for road contamination prevention, because the wheels or tires are covered with dirt, etc. 
         [0006]    Wheels are usually washed in the way of removing contaminants on the wheels or tires while they pass a puddle or a wheel washer ejecting water, but contaminants may flow into the drums of the drum brakes in the wheel-washing and cause noise of the brakes and malfunction due to corrosion. 
         [0007]    Accordingly, air drum brakes of commercial vehicles are equipped with a specific drum cover on predetermined sides to prevent foreign substances from being flowed into the inner sides of the drum and the internal parts including the linings and provide cooling performance by discharging heat; nevertheless, water and foreign substances flow into the drums and exert a bad influence on the barking performance in wheel-washing or raining. 
         [0008]    The structure of a dust cover of the related art and the problem of the structure are described hereafter. 
         [0009]      FIGS. 1 and 2  are views showing the structure of a dust cover of the related art mounted around the inner edge of a drum for drum brakes. 
         [0010]    The dust cover  30  performs cooling by absorbing heat from the drum and discharging it to the outside while preventing foreign substances from flowing into the drum. 
         [0011]    As shown in  FIGS. 1 and 2 , the dust cover  30  of the related art is fastened to an anchor bracket  12  supporting the shoe of the drum brake by bolts, such that it covers the inlet of the drum  10  and closes up the inside of the drum. 
         [0012]    In particular, the inner end portion of the dust cover  30  is fastened to the anchor bracket  12  by bolts and the outer end portion is in close contact with the inner circumferential surface of the drum  10  such that foreign substances can be blocked and heat can be discharged. 
         [0013]    The outer end portion of the dust cover  30  is simply inserted a groove  14  formed along the outer circumferential surface of the drum in close contact with the groove  14  to block foreign substances, so there is a problem in that external air can flow into the drum  10  and water flowing inside is not completely blocked. 
         [0014]    Accordingly, there is a problem that water flows into the drum and contaminants (particles of sand, dirt, and cement etc.) flowing with the water into the drum through the gap between the outer end of the dust cover  30  and the groove  14  of the drum  10  in wheel-washing and raining. 
         [0015]    Further, the contaminants flowing into the drum together with water cause excessive noise in operation of the drum brake or cause scoring (stripes) on the surface of the drum and the lining by sticking on the inner side of the drum, and in some cases, they cause a problem in the braking performance and make it difficult to mount/separate the drum brake in maintenance by sticking on the operation part of the drum brake. 
         [0016]    The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
       BRIEF SUMMARY 
       [0017]    Various aspects of the present invention provide a waterproof device for a drum brake which can minimize not only foreign substances, but also water flowing into a drum, by improving the mounting structure of a dust cover that is mounted at the drum inlet of a drum brake in a new structure that is mounted hermetically and watertightly along the inner circumferential surface of a drum by buoyancy or pressure due to water when passing a puddle or a wheel washer. 
         [0018]    Various aspects of the present invention provide for a waterproof device of a drum brake, which includes: a first dust cover fixed to an anchor bracket for the shoe of a drum brake; and a second dust cover of which the outer end portion is hinged to the outer end portion of the first dust cover and the inner end portion is pivotably inserted into a groove formed at the inlet of a drum, in which the inner end of the second dust cover pivots by buoyancy or external force comes hermetically and watertightly in contact with the side of the groove of the drum. 
         [0019]    A pair of high pin-fixing blocks may be integrally formed on the inner side of the outer end portion of the first dust cover and the outer end portion of the second dust cover may be pivotably connected to the hinge pin-fixing blocks by a hinge shaft. 
         [0020]    A locking wedge, which keeps the second dust cover horizontal by locking to the outer end portion of the first dust cover, may be further integrally formed on the bottom of the outer end portion of the second dust cover. 
         [0021]    A sealing member that can come in close contact with the side of the groove of the drum may be mounted on the top of the inner end portion of the second dust cover. 
         [0022]    The sealing member may be made of foaming resin having low specific gravity in the shape of a rectangular or semicircular block. 
         [0023]    A sealing member formed by stacking a float having low specific gravity and generating buoyancy and a rubber seal capable of coming in close contact with the side of the groove of the drum may be attached to the top of the inner end portion of the second dust cover. 
         [0024]    The rubber seat may be formed in the shape of a rectangular or semicircular block and the float may be made of foaming resin having low specific gravity. 
         [0025]    The sealing member may be made of resin having high thermal resistance considering heat generated from a drum. 
         [0026]    A sub-float having low specific gravity may be further attached to the bottom of the inner end portion of the second dust cover. 
         [0027]    First, it is possible to stop water in addition to foreign substances from flowing into a drum brake by providing an improved structure in which a dust cover mounted at the inlet of a drum of a drum brake comes hermetically and watertightly in close contact with the inner circumferential side of the drum while being moved by buoyancy or pressure due to water. 
         [0028]    Second, since foreign substances and water are stopped from flowing into a drum brake, it is possible to corrosion of a drum brake and abnormal noise in braking, and to improve durability of a drum brake. 
         [0029]    The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]      FIG. 1  is a view showing a mounting structure of a dust cover of the related art; 
           [0031]      FIG. 2  is a view showing a mounting structure of a dust cover of the related art; 
           [0032]      FIG. 3  is a cross-sectional view showing an exemplary waterproof device of a drum brake according to the present invention; 
           [0033]      FIG. 4  is a cross-sectional view showing an exemplary waterproof device of a drum brake according to the present invention; 
           [0034]      FIG. 5  is a cross-sectional view showing an exemplary waterproof device of a drum brake according to the present invention; 
           [0035]      FIG. 6  is a cross-sectional view showing an exemplary waterproof device of a drum brake according to the present invention; and 
           [0036]      FIG. 7  is a schematic view showing the mounting position of a hinge pin-fixing block for a second dust cover of an exemplary waterproof device of a drum brake according to the present invention. 
           [0037]      FIG. 8  is an enlarged schematic view showing the mounting position of a hinge pin-fixing block for a second dust cover of an exemplary waterproof device of a drum brake according to the present invention, taken along line A-A of  FIG. 7 . 
       
    
    
       [0038]    It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
         [0039]    In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
       DETAILED DESCRIPTION 
       [0040]    Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
         [0041]    Various aspects of the present invention have been made to provide a waterproof device of a drum brake which can prevent water in addition to foreign substances from flowing into a drum brake. 
         [0042]      FIG. 3  is a cross-sectional view showing a waterproof device of a drum brake according to various embodiments of the present invention. 
         [0043]    A dust cover  40  of the present invention is composed of a first dust cover  42  that is fixed to an anchor bracket  12  supporting the shoe of a drum brake by bolts and a second dust cover  44  pivotably hinged to the outer end portion of the first dust cover  42 . 
         [0044]    The first dust cover  42  is vertically arranged and the second dust cover  44  is horizontally arranged, such that the first dust cover  42  and the second dust cover  44  are arranged almost at a right angle to each other. 
         [0045]    The first dust cover  42  and the second dust cover  44  perform cooling of absorbing heat from a drum and discharging it to the outside, and particularly, the second dust cover  44  stops foreign substances and water from flowing into the drum, when water pressure or external force is applied. 
         [0046]    To this end, the outer end portion of the second dust cover  44  is hinged to the lower outer end portion of the first dust cover  42  and the inner end is pivotably inserted into a groove  14  formed at the inlet of the drum  10 , for example, along a annular surface of the drum. 
         [0047]    A pair of hinge pin-fixing blocks for hinging the second dust cover  44  is formed, as shown in  FIG. 7 , at a predetermined distance integrally on the inner side of the lower inner end portion of the first dust cover  42 . One will appreciate that such integral components may be monolithically formed. 
         [0048]    Accordingly, both ends of the outer end portion of the second dust cover  44  is pivotably connected to the hinge pin-fixing blocks  16  by hinge shafts  18 . 
         [0049]    In particular, a locking wedge  46  that keeps the second dust cover  44  horizontal by locking to the outer end portion of the first dust cover  42  is integrally formed on the bottom of the outer end portion of the second cover  44 , such that the first dust cover  42  is not turned downward from the horizontal position. One will appreciate that such integral components may be monolithically formed. 
         [0050]    That is, the locking wedge  46  of the second dust cover  44  keeps the second dust cover  44  horizontal, in close contact with the inner side of the outer end portion of the first dust cover  42  vertically arranged, such that the second dust cover  44  does not pivot down about the hinge shaft  18 . 
         [0051]    As the second dust cover  44  keeps horizontal, a predetermined gap is defined formed between the inner end of the second dust cover and the wall of the groove  14  of the drum  10 , such that external air can flow into the drum. 
         [0052]    Therefore, dust collecting in the drum is scattered by external air (cooling air) flowing inside and can be easily discharged out of the drum. 
         [0053]    In contrast, in the wheel-washing, raining, or passing a puddle, water and foreign substances in the water flow into the drum and cause corrosion of the drum brake, which may exert bad influence on the braking performance. 
         [0054]    In order to prevent this problem, a sealing member  50  according to various embodiments of the present invention which can be brought in close contact with the upper side of the groove  14  of the drum  10  is mounted on the top of the inner end portion of the second dust cover  44 . 
         [0055]    The sealing member  50  according to the various embodiments may be the common rubber seal, but it is preferable to use one made of foaming resin, which has low specific gravity and generates buoyancy, in the shape of a rectangular or a semicircular block. 
         [0056]    Therefore, in wheel-washing or raining, and passing a puddle, when buoyancy by water or external force such as water pressure is applied to the inner end portion of the second dust cover  44  and the sealing member  50  on the inner end portion, the inner end of the second cover  44  pivots upward and comes hermetically and watertightly in close contact with the upper side of the groove  14  of the drum  10 , such that it is possible to easily stop water or foreign substances from flowing into the drum. 
         [0057]      FIG. 4  is a cross-sectional view showing a waterproof device of a drum brake according to various embodiments of the present invention. 
         [0058]    The waterproof device of  FIG. 4  has a similar configuration as that shown in  FIG. 3  and is characterized in that a sub-float  56  having low specific gravity is further attached to the bottom of the inner end portion of the second dust cover  44 . 
         [0059]    In detail, with the sealing member  50  shown in  FIG. 3  on the inner end portion of the second dust cover  44 , the sub-float  56  having low specific gravity (e.g. foaming resin) is further attached to the bottom of the inner end portion. 
         [0060]    Therefore, in wheel-washing or raining and passing a puddle, the inner end of the second dust cover  44  more easily pivots to the upper side of the groove  14  of the drum  10  by buoyancy of the sub-float  56  and the sealing member  50  is brought hermetically and watertightly in closer contact with the upper side of the groove  14 , such that it is possible to easily stop water or foreign substances from flowing into the drum. 
         [0061]      FIG. 5  is a cross-sectional view showing a waterproof device of a drum brake according to various embodiments of the present invention. 
         [0062]    The waterproof device of  FIG. 5  has a similar configuration as that of  FIG. 3 , except the sealing member  50  attached to the inner end portion of the second dust  44 . 
         [0063]    The sealing member  50  of  FIG. 5  is composed two stacked materials of a float  52  having low specific gravity, attached to the top of the inner end portion of the second dust cover, and generating buoyancy and a rubber seat  54  stacked on the float  52  in close contact with the upper side of the groove  14  of the drum  10 . 
         [0064]    The rubber seal  54  is formed in the shape of a rectangular or semicircular block to increase the force for close contact with the upper side of the groove  14  and the float  52  is made of foam resin having low specific gravity in the shape of a rectangular block that supports the rubber seat  54 . 
         [0065]    Therefore, in wheel-washing or raining and passing a puddle, the inner end of the second dust cover  44  pivots to the upper side of the groove  14  of the drum  10  by buoyancy of the float  52  and the rubber seal  54  on the float  52  is brought hermetically and watertightly in close contact with the upper side of the groove  14 , such that it is possible to easily stop water or foreign substances from flowing into the drum. 
         [0066]      FIG. 6  is a cross-sectional view showing a waterproof device of a drum brake according to various embodiments of the present invention. 
         [0067]    The waterproof device of  FIG. 6  has the same configuration as that of  FIG. 5  and is characterized in that a float having low specific gravity is further attached to the bottom of the inner end portion of the second dust cover  44 . 
         [0068]    In detail, with the float  52  and the rubber seat  54  of sealing member  50  of  FIG. 5  on the inner end portion of the second dust cover  44 , the sub-float  56  having low specific gravity (e.g., foaming resin) is further attached to the bottom of the inner end portion. 
         [0069]    Therefore, in wheel-washing or raining and passing a puddle, the inner end of the second dust cover  44  more easily pivots to the upper side of the groove  14  of the drum  10  by buoyancy of the sub-float  56  and the rubber seat  54  is brought hermetically and watertightly in closer contact with the upper side of the groove  14 , such that it is possible to easily stop water or foreign substances from flowing into the drum. 
         [0070]    Further, the sealing members in various embodiments may be made of resin having high thermal resistance to prevent deformation due to heat generated from the drum. 
         [0071]    For convenience in explanation and accurate definition in the appended claims, the terms upper and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
         [0072]    The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.