Abstract:
A bush assembly may include an inner pipe, in which a bolt hole is formed substantially in the middle thereof, an outer pipe, through which the inner pipe is inserted, wherein an inner circumference of the outer pipe is spaced with a predetermined gap from an exterior circumference of the inner pipe and the outer pipe includes a bent portion that is bent at a lower portion thereof and extends in a radial direction with a predetermined length, and an elastic member that couples the inner pipe and the outer pipe in the predetermined gap and is fixed to a lower surface of the bent portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority to Korean Patent Application No. 10-2009-0112239 filed on Nov. 19, 2009, the entire contents of which is incorporated herein for all purposes by this reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an engine that is equipped with a bush. More particularly, the present invention relates to an engine that is equipped with a motor driven coolant pump that circulates coolant, and a bush that is interposed between the coolant pump and a cylinder block. 
         [0004]    2. Description of Related Art 
         [0005]    A cooling system of some kind is necessary in any internal combustion engine. If no cooling system were provided, parts would melt from the heat of the burning fuel and pistons would expand so much they would seize. 
         [0006]    The cooling system includes an engine water jacket, a thermostat, a coolant pump, a radiator, a radiator cap, a fan, a fan drive belt, and a coolant pump drive belt. 
         [0007]    Generally, the coolant pump does not have a self-driving torque. Accordingly, the coolant pump uses kinetic energy transferred from the engine crankshaft. 
         [0008]    If the engine is started, the coolant pump is operated regardless of the coolant temperature and the driving condition of the engine in such a manner that the coolant circulates in the water jacket and the radiator of the engine. 
         [0009]    Because the coolant is forcibly circulated before the engine is warmed up, the exhaust gas temperature is increased slowly. Meanwhile, the exhaust gas temperature must be raised to a high temperature, for example 250° C., so as to improve the purification efficiency of the exhaust gas to a normal condition. 
         [0010]    Recently, a motor driven coolant pump has been applied to the engine, and the motor driven coolant pump is only operated during a predetermined period, decreases the warm-up time of the engine, and improves the purification efficiency of the exhaust gas particularly after starting the engine. 
         [0011]    In addition, a fastening device that fixes the coolant pump to the engine and absorbs vibration between them is being developed. 
         [0012]    The information disclosed in this Background of the Invention 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 OF THE INVENTION 
       [0013]    Various aspects of the present invention are directed to provide a bush and an engine that is equipped with the bush having advantages of absorbing vibration and securely fixing a coolant pump to the engine. 
         [0014]    In an aspect of the present invention, the bush assembly may include an inner pipe, in which a bolt hole is formed substantially in the middle thereof, an outer pipe, through which the inner pipe is inserted, wherein an inner circumference of the outer pipe is spaced with a predetermined gap from an exterior circumference of the inner pipe and the outer pipe includes a bent portion that is bent at a lower portion thereof and extends in a radial direction with a predetermined length, and an elastic member that couples the inner pipe and the outer pipe in the predetermined gap and is fixed to a lower surface of the bent portion. 
         [0015]    The elastic member formed at the lower surface of the bent portion may include at least a projecting portion that protrudes in a predetermined distance in a longitudinal direction of the inner pipe from the lower surface of the bent portion. 
         [0016]    At least a penetration hole may be formed in the elastic member fixed between the inner pipe and the outer pipe in a longitudinal direction of the inner pipe, and the at least a penetration hole is arrayed in a circumference direction of the inner pipe with a predetermined distance therebetween. 
         [0017]    The bush assembly may further include an air guide groove formed between the at least a projecting portion at a lower side of the elastic member formed at the lower surface of the bent portion and fluid-communicating with the at least a penetration hole. 
         [0018]    The bush assembly may further include an air releasing groove formed at an upper surface of the elastic member along a circumference direction of the inner pipe and fluid-communicating with the at least a penetration hole. 
         [0019]    A lower end surface of the at least a projecting portion may be disposed lower than a lower end of the inner pipe in a longitudinal direction of the inner pipe, wherein the lower end of the inner pipe is disposed lower than the lower end surface of the bent portion and wherein upper end surfaces of the inner pipe and the outer pipe are disposed on the same level. 
         [0020]    In another aspect, the present invention may include an engine including a cylinder block, a coolant pump that is disposed at one side of the cylinder block, the bush assembly of claim  1 , which is interposed between the coolant pump and the cylinder block, and a fastening bolt that is mounted through the bolt hole of the bush assembly to couple the coolant pump to the cylinder block. 
         [0021]    As stated above, in a bush and an engine that is equipped with the bush according to the present invention, an elastic member such as rubber that is interposed between the inner pipe and the outer pipe absorbs vibration that is formed therebetween, and the bush securely fixes the coolant pump to the engine. 
         [0022]    Further, the elastic member that is formed on the outer surface of the bent portion of the outer pipe to protrude in the length direction of the inner pipe efficiently absorbs the vibration, and securely fixes the coolant pump to the cylinder block of the engine. 
         [0023]    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 of the Invention, which together serve to explain certain principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a perspective view of a coolant pump including an exemplary bush according to the present invention. 
           [0025]      FIG. 2  is a perspective view of an exemplary bush for mounting a coolant pump on an engine according to the present invention. 
           [0026]      FIG. 3  is a sectional perspective view of an exemplary bush for mounting a coolant pump on the engine according to the present invention. 
           [0027]      FIG. 4  is a cross-sectional view showing a coolant pump and an engine that are assembled to each other by an exemplary bush according to the present invention. 
       
    
    
       [0028]    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. 
         [0029]    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 OF THE INVENTION 
       [0030]    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. 
         [0031]    An exemplary embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings. 
         [0032]      FIG. 1  is a perspective view of a coolant pump according to an exemplary embodiment of the present invention. 
         [0033]    Referring to  FIG. 1 , a coolant pump  100  includes a motor housing  110 , a driver case  120 , an impeller housing  130 , and a bracket  140 . 
         [0034]    As constituent elements of electric motor, a stator, a rotor, and a drive shaft are disposed inside the motor housing  110 , and an electric supply set is built in the driver case  120  to supply the stator or the rotor with electrical energy. 
         [0035]    An impeller is disposed in the impeller housing  130 , and an inlet  142  for inhaling the coolant and an outlet  144  for supplying the coolant are formed in the impeller housing  130 . 
         [0036]    The bracket  140  is formed on one side of the exterior circumference of the motor housing  110 , and the coolant pump  100  is mounted on the cylinder block through the bracket  140 . 
         [0037]    A bush  150  is interposed between the bracket and one side surface of the cylinder block, and a fastening bolt  180  penetrates the bracket  140 , the bush  150 , and the cylinder block  160  to securely fix the coolant pump  100  to the cylinder block  160 . 
         [0038]    The bush  150  fixes the coolant pump  100  to the cylinder block, and simultaneously absorbs vibration that is formed between the coolant pump  100  and the cylinder block. 
         [0039]    Referring to  FIG. 2  and  FIG. 3 , a detail structure of the bush  150  is explained. 
         [0040]      FIG. 2  is a perspective view of a bush for mounting a coolant pump on an engine according to an exemplary embodiment of the present invention, and  FIG. 3  is a sectional perspective view of a bush for mounting a coolant pump on the engine according to an exemplary embodiment of the present invention. 
         [0041]    Referring to  FIG. 2 , the bush  150  includes an inner pipe  200 , an outer pipe  210 , and an elastic member  220 . 
         [0042]    A bolt hole  205  is formed along the center axis of the inner pipe  200 , the interior circumference of the outer pipe  210  is disposed with a predetermined gap from the exterior circumference of the inner pipe  200 , and the elastic member  220  is interposed between the inner pipe  200  and the outer pipe  210 . 
         [0043]    Here, because the elastic member  220  is a flexible material such as rubber, it is effective for absorbing the vibration between the inner pipe  200  and the outer pipe  210 . 
         [0044]    Penetration holes  225  that are interposed between the inner pipe  200  and the outer pipe  210  are formed in the elastic member  220 . The vibration or the oscillation that is formed between the inner pipe  200  and the outer pipe  210  is effectively absorbed through the penetration holes  225 . 
         [0045]    Referring to  FIG. 3 , the inner pipe  200  is inserted through the outer pipe  210 , and one end of the outer pipe  210  is bent in an outer side direction to form a bent portion  230  along the circumference direction of the outer pipe  210 . 
         [0046]    The elastic member  220  is interposed between the inner pipe  200  and the outer pipe  210 , and is formed on the outer side surface of the bent portion  230 . 
         [0047]    Further, the elastic member  220  protrudes on the outer side surface of the bent portion  230  to form a projecting portion  300 . The projecting portion  300  is formed along the bent portion  230  with a predetermined gap at an exterior circumference of the outer pipe  210 . 
         [0048]    As shown in  FIG. 3 , the penetration hole  225  is formed in the elastic member  220  that is interposed between the inner pipe  200  and the outer pipe  210 , and it is desirable that the projecting portion  300  is not formed corresponding to the penetration holes  225 . 
         [0049]      FIG. 4  is a cross-sectional view showing a coolant pump and an engine that are assembled to each other according to an exemplary embodiment of the present invention. 
         [0050]    Referring to  FIG. 4 , the bush  150  is interposed between the cylinder block  160  and the bracket  140  of the motor housing  110  of the coolant pump  100 , and the bolt  180  is disposed to penetrate the bracket  140 , the bolt hole  205  of the bush  150 , and the cylinder block  160 . 
         [0051]    Here, a nut  170  is engaged with both ends of the bolt  180  to fix the bracket  140  on the cylinder block  160 . 
         [0052]    The bush  150  that is interposed between the bracket  140  and the cylinder block  160  has a structure that absorbs the vibration between the coolant pump  100  and the cylinder block  160 . 
         [0053]    Further, the lower end portions of the inner pipe  200  and the outer pipe  210  do not contact the surface of the cylinder block  160 . That is, a predetermined gap (G) is formed between the lower end of the inner pipe and an upper surface of the cylinder block  160 . 
         [0054]    In an exemplary embodiment of the present invention, the inner pipe  200  has a first length d 1  from the upper end of the bush, the outer pipe has a second length d 2  from the upper end of the bush, and the bush has a third length d 3  from the upper end thereof, wherein the third length d 3  is longer than the second length d 2 , and the second length d 2  is longer than the first length d 1 . 
         [0055]    More specifically, the projecting portion  300  of the elastic member  220  is interposed between a lower surface  405  of the bent portion  230  and the upper surface  410  of the cylinder block  160 . 
         [0056]    Accordingly, the vibration of the cylinder block  160  is absorbed by the projecting portion  300 , and conversely the vibration of the bracket  140  is not directly transferred to the cylinder block  160 . 
         [0057]    Further, the bent portion  230  has a structure that is bent at the outer side of the outer pipe  210 , and the elastic member  220  is formed on the outer side surface of the bent portion  230  in such a manner that the projecting portion  300  with a wide area contacts with the upper surface  410  of the cylinder block  160  to improve the assembly strength. 
         [0058]    In an exemplary embodiment of the present invention, the projecting portion  300  is formed along the bent portion  230  with a predetermined gap in such a manner that the vibration absorption performance is improved. 
         [0059]    In another exemplary embodiment of the present invention, an air guide groove  250  may be formed between the projecting portions  300  to fluid-communicate with the penetration hole  225  such that air trapped in the penetration hole  225  may be released therethrough while the projection portion  300  is compressed. 
         [0060]    In further another exemplary embodiment of the present invention, an air releasing groove  240  may be formed at upper portion of the elastic member  220  along a circumference direction thereof and fluid-communicate with the penetration hole  225 . In this configuration, the air trapped in the penetration holes  225  fluid-communicating with each other through the air releasing groove  240  may be effectively released through the air guide groove  250  while the projection portion  300  is compressed. 
         [0061]    For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “interior”, “exterior”, “outer”, and “inner” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
         [0062]    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.