Abstract:
The present invention provides a joint cover capable of improving working efficiency in mounting a joint cover on a joint. A joint cover provided on the outside of a joint includes a first cover body provided with an opening and adapted to house one side of the joint; and a second cover body detachably attachable to the first cover body, wherein a dividing position formed when the first cover body and the second cover body are in contact with each other is offset toward the second cover body.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a joint cover, and more particularly, to a joint cover provided over a joint used for urea water supply piping. 
       BACKGROUND ART 
       [0002]    Urea water supply piping is used for an exhaust purification system adapted to purify nitrogen oxides (hereinafter referred to as “NOx”) in internal combustion engines such as diesel engines. Such an exhaust purification system is disclosed, for example, in Patent Literature 1, where the disclosed exhaust purification system includes a catalyst provided in an exhaust passage of an internal combustion engine and a urea water addition valve provided on an upstream side of the catalyst. Urea water is stored in a tank, force-fed to a urea water addition valve by a pump through a urea water supply pipe, and added into the exhaust passage through the urea water addition valve. Consequently, the urea water is broken down into ammonia, and NOx in exhaust is selectively reduced on the catalyst by the ammonia, thereby purifying the exhaust. 
         [0003]    Urea water freezes at around −11° C., presenting a problem in that the urea water can freeze in urea water supply piping depending on the use environment, which may make it impossible to supply the urea water to the exhaust passage. 
         [0004]    To deal with this, a joint connected to a urea water supply pipe and provided with a heating wire for use to heat urea water is disclosed (e.g. Patent Literature 2). Also, the joint is provided with a joint cover for protection against the wind. The joint cover is made up of two housings shaped to be symmetrical to each other and the housings are mounted on the joint by attaching the joint to a first of the housings and then fixing a second of the housings to the first of the housings in such a way as to cover the joint from above. 
       CITATION LIST 
     Patent Literature 
       [0005]    Patent Literature 1: Japanese Patent Laid-Open No. 2010-71270 
         [0006]    Patent Literature 2: U.S. Pat. No. 8,526,801 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0007]    In the case of Patent Literature 2, since the housings are shaped to be symmetrical to each other, the first housing covers only half an outer circumference of the joint and consequently, when the joint is attached to the first housing, the joint is not stable. This poses a problem of poor working efficiency in mounting the joint cover on the joint. Also, there is a problem in that in fixing the second housing to the first housing and covering the joint with the joint cover, the heating wire tends to be pinched between the housings. 
         [0008]    Thus, an object of the present invention is to provide a joint cover capable of improving working efficiency in mounting a joint cover on a joint. 
       Solution to Problem 
       [0009]    The present invention provides a joint cover provided on the outside of a joint, the joint cover comprising: a first cover body provided with an opening and adapted to house one side of the joint; and a second cover body detachably attachable to the first cover body, wherein a dividing position formed when the first cover body and the second cover body are in contact with each other is offset toward the second cover body. 
       Advantageous Effects of Invention 
       [0010]    According to the present invention, since the dividing position is formed at a position offset toward the second cover body, the first cover body can house more than half an outer circumference of the joint. Consequently, in attaching the first cover body to the joint, the first cover body can hold the joint more stably, making it possible to improve working efficiency in mounting the joint cover to the joint. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0011]      FIG. 1  is a perspective view showing how a joint cover according to a first embodiment is used; 
           [0012]      FIG. 2  is an exploded perspective view showing an overall configuration of the joint cover according to the first embodiment; 
           [0013]      FIG. 3  is an exploded perspective view seen from the side opposite to  FIG. 2 , showing an overall configuration of the joint cover according to the first embodiment; 
           [0014]      FIG. 4  is an end view of the joint cover according to the first embodiment; 
           [0015]      FIG. 5  is a perspective view showing how the joint cover according to the first embodiment is mounted on the joint; 
           [0016]      FIG. 6  is an exploded perspective view showing a configuration of a joint cover according to a modification of the first embodiment; 
           [0017]      FIG. 7  is a perspective view showing a configuration of a joint cover according to a second embodiment; 
           [0018]      FIG. 8  is an exploded perspective view showing the configuration of the joint cover according to the second embodiment; 
           [0019]      FIG. 9  is an exploded perspective view showing a configuration of a joint cover according to a modification of the second embodiment; 
           [0020]      FIG. 10  is a perspective view showing the configuration of the joint cover according to the first embodiment; 
           [0021]      FIG. 11  is a front view showing the configuration of the joint cover according to the first embodiment; 
           [0022]      FIG. 12  is a rear view showing the configuration of the joint cover according to the first embodiment; 
           [0023]      FIG. 13  is a left side view showing the configuration of the joint cover according to the first embodiment; 
           [0024]      FIG. 14  is a right side view showing the configuration of the joint cover according to the first embodiment; 
           [0025]      FIG. 15  is a plan view showing the configuration of the joint cover according to the first embodiment; 
           [0026]      FIG. 16  is a bottom view showing the configuration of the joint cover according to the first embodiment; 
           [0027]      FIG. 17  is an exploded perspective view showing the configuration of the joint cover according to the first embodiment; 
           [0028]      FIG. 18  is a perspective view showing a configuration of the joint cover according to the modification of the first embodiment; 
           [0029]      FIG. 19  is a front view showing the configuration of the joint cover according to the modification of the first embodiment; 
           [0030]      FIG. 20  is a rear view showing the configuration of the joint cover according to the modification of the first embodiment; 
           [0031]      FIG. 21  is a left side view showing the configuration of the joint cover according to the modification of the first embodiment; 
           [0032]      FIG. 22  is a right side view showing the configuration of the joint cover according to the modification of the first embodiment; 
           [0033]      FIG. 23  is a plan view showing the configuration of the joint cover according to the modification of the first embodiment; 
           [0034]      FIG. 24  is a bottom view showing the configuration of the joint cover according to the modification of the first embodiment; 
           [0035]      FIG. 25  is an exploded perspective view showing the configuration of the joint cover according to the modification of the first embodiment; 
           [0036]      FIG. 26  is a perspective view showing the configuration of the joint cover according to the second embodiment; 
           [0037]      FIG. 27  is a front view showing the configuration of the joint cover according to the second embodiment; 
           [0038]      FIG. 28  is a rear view showing the configuration of the joint cover according to the second embodiment; 
           [0039]      FIG. 29  is a left side view showing the configuration of the joint cover according to the second embodiment; 
           [0040]      FIG. 30  is a right side view showing the configuration of the joint cover according to the second embodiment; 
           [0041]      FIG. 31  is a plan view showing the configuration of the joint cover according to the second embodiment; 
           [0042]      FIG. 32  is a bottom view showing the configuration of the joint cover according to the second embodiment; 
           [0043]      FIG. 33  is an exploded perspective view showing the configuration of the joint cover according to the second embodiment; 
           [0044]      FIG. 34  is a perspective view showing the configuration of the joint cover according to the modification of the second embodiment; 
           [0045]      FIG. 35  is a front view showing the configuration of the joint cover according to the modification of the second embodiment; 
           [0046]      FIG. 36  is a rear view showing the configuration of the joint cover according to the modification of the second embodiment; 
           [0047]      FIG. 37  is a left side view showing the configuration of the joint cover according to the modification of the second embodiment; 
           [0048]      FIG. 38  is a right side view showing the configuration of the joint cover according to the modification of the second embodiment; 
           [0049]      FIG. 39  is a plan view showing the configuration of the joint cover according to the modification of the second embodiment; 
           [0050]      FIG. 40  is a bottom view showing the configuration of the joint cover according to the modification of the second embodiment; and 
           [0051]      FIG. 41  is an exploded perspective view showing the configuration of the joint cover according to the modification of the second embodiment. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0052]    Embodiments of the present invention will be described in detail below with reference to the drawings. The terms “top” (or up or upper) and “bottom” (or down or lower) used herein indicate “top” and “bottom” in the drawings, respectively, and are used simply for convenience of explanation, and, needless to say, the top and bottom may actually be reversed or positioned on the left and right. 
       1. First Embodiment 
     (1) Overall Configuration 
       [0053]    A joint cover  10 A shown in  FIG. 1  includes a first cover body  12  and a second cover body  14  and is provided on the outside of a joint  16 A. The joint  16 A is connected with a urea water supply pipe  20 , which is a tubular body. The urea water supply pipe  20  is inserted in a corrugated tube  22  serving as a protective tube. 
         [0054]    As shown in  FIG. 2 , the joint cover  10 A is formed by the first cover body  12  and the second cover body  14  so as to be divisible in two in an up-and-down direction. A dividing position D 1  between the first cover body  12  and the second cover body  14  is formed at a position offset toward the second cover body  14  from a center of an outer circumference of the joint  16 A. That is, the first cover body  12  takes up more than half, e.g. two-thirds of the outer circumference of the joint cover  10 A. The second cover body  14  is configured to take up less than half, e.g. one-third of the outer circumference of the joint cover  10 A. Although not particularly limited, the joint cover  10 A is made of synthetic resin, and preferably made, for example, of polyamide (including aromatic polyamide), polybutylene terephthalate, polyethylene terephthalate, polyethylene, polyvinyl chloride, ABS, polypropylene, polyacetal, polyether ketone, fluoroplastics, or the like. 
         [0055]    In  FIG. 2 , the first cover body  12  is a container-shaped member which has an opening in upper part and includes a substantially rectangular base  13  and side faces  15  formed integrally on the sides of the base  13 . The first cover body  12  is formed such that length from the base  13  to an upper end of the side face  15  is longer than a radius of an outside diameter of the joint  16 A. That is, the side faces  15  are formed high enough to cover lateral parts of the joint  16 A attached to the first cover body  12 . 
         [0056]    A first holding portion  24  adapted to hold the corrugated tube  22  is provided on one end of the first cover body  12 . The first holding portion  24  includes plural lamellar members and has a curved concave bottom  25  and walls  26  formed on opposite ends of the bottom  25 . The wall  26  is formed such that length from the bottom  25  to an upper end is longer than a radius of an outside diameter of the corrugated tube  22 . Thereby, with the use of the bottom  25  and the walls  26 , the first holding portion  24  is able to hold lower part and lateral parts of the corrugated tube  22 . 
         [0057]    The first cover body  12  is provided with a first housing portion  27 , which houses heating wires (not illustrated) and is located adjacent to the first holding portion  24 . The first housing portion  27  includes a curved concave bottom  29  and housing walls  31  formed on opposite ends of the bottom  29 . The plural heating wires, being tied in a bundle, are housed in the first housing portion  27 . The housing wall  31  is formed such that length from the bottom  29  to an upper end of the housing wall  31  is longer than an overall outside diameter of the bundled heating wires. 
         [0058]    The second cover body  14  is a lid-shaped member configured to be able to cover the opening of the first cover body  12 . A second holding portion  28  adapted to hold an upper part of the corrugated tube  22  is provided on one end of the second cover body  14 . The second holding portion  28  includes plural lamellar members and is formed into a curved concave shape, and provided with convex portions  23  formed on opposite ends. The convex portion  23  has a shape protruding toward the first cover body  12 . 
         [0059]    The second cover body  14  is provided with a second housing portion  33 , which is located adjacent to the second holding portion  28  and adapted to cover an opening of the first housing portion  27 . The second housing portion  33  is formed into a curved concave shape and provided with convex portions  35  formed on opposite ends. 
         [0060]    As shown in  FIG. 3 , a first outer circumference holding portion  37  is provided on another end of the first cover body  12 . The first outer circumference holding portion  37  is formed into a curved concave shape, integrally with the side faces  15 . A second outer circumference holding portion  39  is provided on another end of the second cover body  14 . The second outer circumference holding portion  39  is formed into a curved concave shape. The second cover body  14  is formed in such a way that an operating portion (described later) provided on the joint  16 A can be exposed. 
         [0061]    As shown in  FIG. 3 , the joint  16 A includes a first terminal portion  30  serving as a terminal portion, and a second terminal portion  32  formed coaxially with the first terminal portion  30 . The first terminal portion  30  is provided with an operating portion  18 . The operating portion  18  is configured to be able to operate a clamping mechanism allowing a pipe (not illustrated) that is a tubular body inserted in the first terminal portion  30 , to be connected to or disconnected from the joint  16 A. The urea water supply pipe  20  is to be connected with the second terminal portion  32 . 
         [0062]    In the joint cover  10 A, as shown in  FIG. 4 , the second cover body  14  is placed to cover the opening of the first cover body  12  and is fixed to the first cover body  12 , thereby forming a holding portion  41  and a housing portion  43 . That is, the holding portion  41  is formed of the first holding portion  24  and the second holding portion  28 . The convex portions  23  of the second holding portion  28  are disposed within the walls  26  of the first holding portion  24 . The housing portion  43  is formed of the first housing portion  27  and the second housing portion  33 . Although not illustrated, the first outer circumference holding portion  37  and the second outer circumference holding portion  39  make up an outer circumference holding portion. 
         [0063]    A method for attaching the joint cover  10 A with the above configuration will be described. First, as shown in  FIG. 5 , the first cover body  12  is attached to the joint  16 A connected with the urea water supply pipe  20 . The first holding portion  24  is inserted into grooves formed on an outer circumference of the corrugated tube  22  and thereby holds the lower part and the lateral parts of the corrugated tube  22 . In so doing, since the side faces  15  of the first cover body  12  are formed high enough to cover the lateral parts of the joint  16 A, the first cover body  12  is able to hold the joint  16 A more stably. Although not illustrated, the heating wires are housed in the first housing portion  27  and led out of the first cover body  12 . 
         [0064]    Next, the second cover body  14  is fixed to the first cover body  12  to cover the opening of the first cover body  12  and the joint  16 A, and thus the joint  16 A is covered with the joint cover  10 A ( FIG. 1 ). The second holding portion  28  is inserted into the grooves formed on the outer circumference of the corrugated tube  22  and thereby holds the upper part of the corrugated tube  22 . Consequently, the corrugated tube  22  is held by the holding portion  41 . The heating wire is led out of the joint cover  10 A through the housing portion  43 . A first terminal portion  30  side of the joint  16 A is held by the outer circumference holding portion. According to the present embodiment, the first terminal portion  30  of the joint  16 A is exposed without being covered with the joint cover  10 A. Detail views of the joint cover  10 A according to the present embodiment are shown in  FIG. 10  to  FIG. 17 . 
       (2) Operation and Effects 
       [0065]    As described above, being configured such that the side faces  15  are high enough to cover the lateral parts of the joint  16 A, the first cover body  12  is capable of housing more than half the outer circumference of the joint  16 A. Consequently, when being attached to the joint  16 A, the first cover body  12  is able to hold the joint  16 A more stably. Thus, the joint cover  10 A is able to improve working efficiency in attaching the joint cover  10 A to the joint  16 A. 
         [0066]    The convex portions  23  are disposed within the walls  26  of the first holding portion  24 , so that the second holding portion  28  is able to hold the upper part of the corrugated tube  22  more reliably. Thus, by simply fixing the second cover body  14  to the first cover body  12 , the joint cover  10 A is able to hold the corrugated tube  22  more reliably, and thereby improves the working efficiency in attaching the joint cover  10 A to the joint  16 A. 
         [0067]    Since the housing walls  31  are formed such that the length from the bottom  29  to the upper end of the housing wall  31  is longer than the outside diameter of the heating wire, the heating wires are housed more reliably. Thus, the joint cover  10 A avoids pinching the heating wires when being attached to the joint  16 A and thereby further improves working efficiency. 
         [0068]    Since the dividing position between the first cover body  12  and the second cover body  14  is offset toward the second cover body  14  from the center, the first cover body  12  and the second cover body  14  are shaped to be asymmetrical to each other. Thus, in attaching the joint cover  10 A to the joint  16 A, the joint cover  10 A is able to prevent mixing up of the first cover body  12  and the second cover body  14 , and thereby a sequence of operation is unified and working efficiency is further improved. 
         [0069]    Since the joint cover  10 A is formed so as to expose the operating portion  18  provided on the first terminal portion  30 , the operating portion  18  can be operated and pipes can be connected to and disconnected from the first terminal portion  30 , with the joint cover  10 A remaining attached to the joint  16 A. Thus, the joint cover  10 A improves working efficiency in connecting pipes. 
       (3) Modification 
       [0070]    Whereas the joint cover  10 A according to the first embodiment described above is used for the joint  16 A in which the first terminal portion  30  and the second terminal portion  32  are provided coaxially, the present invention is not limited to this. For example, as shown in  FIG. 6 , the joint cover  10 A may be used for a so-called elbow joint  16 B in which a center axis of the first terminal portion  30  and a center axis of the second terminal portion  32  are placed at right angles to each other. In this case, to fit the shape of the joint  16 B, each of a first cover body  34  and a second cover body  36  of the joint cover  10 B is formed into an elbow shape. Detail views of the joint cover  10 B according to the present modification are shown in  FIG. 18  to  FIG. 25 . 
       2. Second Embodiment 
     (1) Overall Configuration 
       [0071]    Next, a joint cover  10 C according to a second embodiment of the present invention will be described. The joint cover  10 C according to the present embodiment differs from the first embodiment described above in the configuration of an outer circumference holding portion. Components similar to those in the first embodiment described above are denoted by reference numerals similar to the corresponding components, and description thereof will be omitted. 
         [0072]    A joint cover  10 C shown in  FIG. 7  includes a first cover body  38  and a second cover body  40 . The joint cover  10 C is formed of the first cover body  38  and the second cover body  40  so as to be divisible in two in the left-and-right direction in  FIG. 7 . A dividing position D 2  between the first cover body  38  and the second cover body  40  is formed at a position offset toward the second cover body  40 . 
         [0073]    As shown in  FIG. 8 , a first outer circumference holding portion  42  provided on the first cover body  38  has a first outer circumferential wall  45  formed on one side with respect to a center axis. The first outer circumferential wall  45  has a height approximately equal in length to a radius of an outside diameter of a first terminal portion  50  and is formed integrally with the side face  15 . A first notch  44  with the side face  15  removed is formed on the other side of the first outer circumference holding portion  42  with respect to the center axis. 
         [0074]    A second outer circumference holding portion  46  provided on the second cover body  40  has a second outer circumferential wall  47  formed on one side with respect to the center axis. The second outer circumferential wall  47  has a height approximately equal in length to the radius of the outside diameter of the first terminal portion  50 . A second notch  48  is formed on the other side of the second outer circumference holding portion  46  with respect to the center axis. 
         [0075]    As shown in  FIG. 8 , a joint  16 C includes the first terminal portion  50 , and a second terminal portion  52  formed coaxially with the first terminal portion  50 . An operating portion  54  is provided on the other side of the first terminal portion  50  with respect to the center axis. Detail views of the joint cover  10 C according to the present embodiment are shown in  FIG. 26  to  FIG. 33 . 
         [0076]    In the joint cover  10 C configured as described above, the second cover body  40  is placed to cover an opening of the first cover body  38  and the second cover body  40  is fixed to the first cover body  38 , thereby forming the outer circumference holding portion. That is, the outer circumference holding portion is formed by the first outer circumference holding portion  42  and the second outer circumference holding portion  46 . The first outer circumferential wall  45  and the second outer circumferential wall  47  of the outer circumference holding portion covers one side of the first terminal portion  50  with respect to the center axis. A dividing position on the one side of the first terminal portion  50  is formed at an approximate center of an outer circumference of the joint  16 C. On the other side of the outer circumference holding portion, an access window is formed by the first notch  44  and the second notch  48 . The operating portion  54  of the joint  16 C is exposed through the access window. 
       (2) Operation and Effects 
       [0077]    Since the side faces  15  of the first cover body  38  are formed high enough to cover lateral parts of the joint  16 C, the joint cover  10 C according to the present embodiment achieves effects similar to those of the first embodiment described above. 
         [0078]    According to the present embodiment, since each of the first outer circumferential wall  45  and the second outer circumferential wall  47  is formed approximately equal in length to the radius of the outside diameter of the first terminal portion  50 , the dividing position on the one side of the first terminal portion  50  is formed at an approximate center of the outer circumference of the joint  16 C. Thus, the part of the joint cover  10 C which covers the first terminal portion  50  can be downsized. 
       (3) Modification 
       [0079]    Whereas the joint cover  10 C according to the second embodiment described above is used for the joint  16 C in which the first terminal portion  50  and the second terminal portion  52  are provided coaxially, the present invention is not limited to this. For example, as shown in  FIG. 9 , the joint cover  10 C may be a so-called elbow joint  16 D in which a center axis of the first terminal portion  50  and a center axis of the second terminal portion  52  are at right angles to each other. In this case, to fit the shape of the joint  16 D, a first cover body  56  and a second cover body  58  of the joint cover  10 D are formed into an elbow shape. Detail views of the joint cover  10 D according to the present modification are shown in  FIG. 34  to  FIG. 41 . 
       3. Modifications 
       [0080]    The present invention is not limited to the above embodiments, and may be changed as appropriate within the spirit and scope of the present invention. 
       REFERENCE SIGNS LIST 
       [0081]      10 A,  10 B,  10 C,  10 D Joint cover
     12  First cover body     14  Second cover body     16 A,  16 B,  16 C,  16 D Joint     20  Urea water supply pipe (tubular body)     22  Corrugated tube (protective tube)     23  Convex portion     24  First holding portion     28  Second holding portion     30  First terminal portion (terminal portion)     32  Second terminal portion (terminal portion)     41  Holding portion   D 1  Dividing position