Patent Publication Number: US-2019191596-A1

Title: Electrical apparatus

Description:
INCORPORATION BY REFERENCE 
     The disclosure of Japanese Patent Application No. 2017-242147 filed on Dec. 18, 2017 including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The disclosure relates to an electrical apparatus configured to be mounted in a vehicle. 
     2. Description of Related Art 
     A control unit (electrical apparatus) that is mounted in a vehicle is described in Japanese Patent Application Publication No. 2012-64724 (JP 2012-64724 A). The vehicle is a hybrid vehicle that includes an engine and a motor, and the control unit is a device that controls driving electric power for a motor. In a front compartment, the control unit is fixed on a case of a drive system including the motor. 
     A cooler in which a liquid refrigerant is used is accommodated together with a large number of electrical components in a case of the control unit. A refrigerant pipe that is connected to the cooler extends through a wall of the case and extends to the outside of the case. The liquid refrigerant is supplied from the outside through the refrigerant pipe. The refrigerant that has absorbed heat from the electrical components is discharged to the outside of the case through another refrigerant pipe. 
     SUMMARY 
     When a collision load, which is generated at the time of collision of the vehicle, is applied to the refrigerant pipe in the control unit described in JP 2012-64724 A, the refrigerant pipe may be pushed into the case, and thus, the cooler in the case may be damaged and the refrigerant may leak in the case. The leakage of the refrigerant in the case may cause the damage to the electrical components that are accommodated in the case. 
     An aspect of the disclosure relates to an electrical apparatus configured to be mounted in a vehicle. The electrical apparatus includes a case that accommodates an electrical component; a cooler accommodated in the case and configured to cool the electrical component with use of a liquid refrigerant; and a refrigerant pipe that extends through a wall of the case and is connected to the cooler. A notch is provided on an outer surface of the refrigerant pipe such that the notch is located outside the case. 
     In the electrical apparatus, when a collision load, which is generated at the time of a collision of the vehicle, is applied to the refrigerant pipe, the notch, which is located outside the case, is first broken, and the refrigerant can be discharged to the outside of the case from the notch. As a result, it is possible to prevent the refrigerant from leaking in the case. Therefore, it is possible to prevent damage to the electrical apparatus, which is caused by the leakage of the refrigerant, at the time of the collision of the vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
         FIG. 1  is an explanatory view showing a schematic configuration of a vehicle that is seen from above; 
         FIG. 2  is an explanatory view showing the schematic configuration of the vehicle that is seen from the left; 
         FIG. 3  is a perspective view showing a detailed configuration of an electric power control unit in a first embodiment, the electric power control unit being mounted in the vehicle; 
         FIG. 4  is a sectional view showing the detailed configuration of the electric power control unit that is seen along arrows in  FIG. 3 ; 
         FIG. 5  is a partial sectional view showing the detailed configuration of the electric power control unit that is seen along arrows in  FIG. 3 ; 
         FIG. 6  is an explanatory view showing an example of a state where a pipe portion of the electric power control unit is broken; 
         FIG. 7  is a partial sectional view showing a detailed configuration of an electric power control unit in a second embodiment; 
         FIG. 8  is a sectional view showing a detailed configuration of a pipe portion that is seen along arrows in  FIG. 7 ; 
         FIG. 9  is an explanatory view showing an example of a state where the pipe portion of the electric power control unit is broken; and 
         FIG. 10  is a sectional view showing the detailed configuration of the pipe portion that is seen along arrows in  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, a first embodiment of the disclosure will be described.  FIG. 1  is an explanatory view showing a schematic configuration of a vehicle  100  that is seen from above.  FIG. 2  is an explanatory view showing the schematic configuration of the vehicle  100  that is seen from the left. Each of  FIG. 1  and  FIG. 2  shows a front portion of the vehicle  100 . In the vehicle  100 , an electric motor generates at least part of power for driving drive wheels. The vehicle  100  is a hybrid vehicle that includes, as power sources, the electric motor and an engine. In the following description, the electric motor will be simply referred to as a motor. In a coordinate system in each of  FIG. 1  and  FIG. 2 , each of “front”, “rear”, “right”, “left”, “up”, and “down” signifies a direction with respect to the vehicle  100 . The same applies to the other drawings, which will be described below. 
     The vehicle  100  includes a vehicle body  110 , an engine  120 , a transaxle  121 , and an electric power control unit  200 . A motor  122  is accommodated in the transaxle  121 . The engine  120  and the transaxle  121  are coupled to each other in a vehicle width direction. An output shaft of the engine  120  and an output shaft of the motor  122  are moved in conjunction with each other by a gear set that is provided in the transaxle  121 . A power supply (not shown) for driving the motor  122  is mounted in a rear portion of the vehicle  100 . 
     The electric power control unit  200  of the vehicle  100  is fixed on the transaxle  121 . The electric power control unit  200  is fixed on the transaxle  121  in a state in which the electric power control unit  200  is inclined downward in a forward direction. The electric power control unit  200  controls driving electric power for the motor  122 . The electric power control unit  200  is also referred to as a power control unit (PCU). The electric power control unit  200  includes a case  210  and a first external refrigerant pipe  230 . 
     The case  210  accommodates an electrical component and a cooler that cools the electrical component. The first external refrigerant pipe  230  is fixed to an outer side of the case  210 . The first external refrigerant pipe  230  extends obliquely downward toward the front side of the vehicle  100  from a front surface of the case  210 . In the first external refrigerant pipe  230 , a channel through which a refrigerant flows is formed. The first external refrigerant pipe  230  is connected to a refrigerant circulator (not shown) that circulates the refrigerant. The refrigerant flows from the outside of the electric power control unit  200  into the case  210  through the first external refrigerant pipe  230 . A detailed configuration of the electric power control unit  200  will be described below. 
     The vehicle body  110  of the vehicle  100  forms a contour of the vehicle  100 . The vehicle body  110  includes an engine compartment  112  provided in the front portion of the vehicle  100 . In the engine compartment  112 , the engine  120 , the transaxle  121  (the motor  122 ), the electric power control unit  200 , and the like are arranged. The vehicle body  110  includes mounts  114 ,  116 . The mount  114  supports a suspension (not shown) for a right front wheel. The mount  116  supports a suspension (not shown) for a left front wheel. 
     The mount  114  is located at a right end in the engine compartment  112 . The mount  116  is located at a left end in the engine compartment  112 . The engine  120  and the transaxle  121  are located between the mount  114  and the mount  116 , and protrude in a front-rear direction beyond the mounts  114 ,  116  (more specifically, the engine  120  and the transaxle  121  protrude forward beyond the mounts  114 ,  116 , and protrude rearward beyond the mounts  114 ,  116 ). 
     The electric power control unit  200  is located on a left side of the engine  120  and is located on a right side of the mount  116 . The electric power control unit  200  is provided between the engine  120  and the mount  116 . The first external refrigerant pipe  230  of the electric power control unit  200  extends obliquely downward toward the front side of the vehicle  100  (in a direction of an arrow PD in  FIG. 2 ) from the front surface of the case  210 . The first external refrigerant pipe  230  projects toward the front side beyond the engine  120 . 
       FIG. 3  is a perspective view showing the detailed configuration of the electric power control unit  200  that is mounted in the vehicle  100 .  FIG. 4  is a sectional view showing the detailed configuration of the electric power control unit  200  that is seen along arrows IV-IV in  FIG. 3 . In addition to the case  210  and the first external refrigerant pipe  230 , the electric power control unit  200  includes a cooler  220 , a second external refrigerant pipe  240 , a third external refrigerant pipe  250 , and a plurality of electrical components  300 . 
     The first external refrigerant pipe  230  of the electric power control unit  200  guides the refrigerant into the case  210 . The third external refrigerant pipe  250  of the electric power control unit  200  is used to discharge the refrigerant to the outside of the case  210  (in other words, the refrigerant is discharged to the outside of the case  210  through the third external refrigerant pipe  250 ). The third external refrigerant pipe  250  is located on a front side of the case  210 . Similarly to the first external refrigerant pipe  230 , the third external refrigerant pipe  250  extends obliquely downward toward the front side of the vehicle  100  from the front surface of the case  210 . 
     In the electric power control unit  200 , the case  210  thereof accommodates the plurality of electrical components  300  and the cooler  220 . The electrical components  300  constitute a power module in which a plurality of power semiconductor elements (power devices) are enclosed. Each of the electrical components  300  generates heat when energized, and is cooled by the cooler  220 . 
     The cooler  220  includes a plurality of cooling plates  226 . The plurality of cooling plates  226  and the plurality of electrical components  300  are stacked alternately one by one. Each of the cooling plates  226  is hollow, and the refrigerant flows through the inside of the cooling plate  226 . The cooling plates  226  adjacent to each other communicate with each other at two positions. In  FIG. 4 , a first internal refrigerant pipe  228  and a second internal refrigerant pipe  229  are connected to the cooling plate  226  at a left end. The first internal refrigerant pipe  228  is connected to the first external refrigerant pipe  230  via a gasket  239 . The second internal refrigerant pipe  229  is connected to the second external refrigerant pipe  240  via a gasket  249 . Each of the gaskets  239 ,  249  is made of a resin. The refrigerant is supplied to the cooler  220  via the first external refrigerant pipe  230  and the first internal refrigerant pipe  228 . The refrigerant that has been supplied to the cooler  220  is distributed to the plurality of cooling plates  226 . While flowing through each of the cooling plates  226 , the refrigerant absorbs the heat of the electrical component(s)  300  adjacent to the cooling plate  226 . The refrigerant that has absorbed the heat is delivered to another cooler via the second internal refrigerant pipe  229  and the second external refrigerant pipe  240 . The other cooler is accommodated in a lower portion of the case  210 . The refrigerant that has flowed through the other cooler is discharged to the outside of the case  210  via the third external refrigerant pipe  250 . As described above, the refrigerant is circulated between the refrigerant circulator, which is not shown, and the electric power control unit  200 . 
       FIG. 5  is a partial sectional view showing the detailed configuration of the electric power control unit  200  that is seen along arrows V-V in  FIG. 3 . In the electric power control unit  200 , a body  234  of the first external refrigerant pipe  230  has an axis AX that extends in an obliquely downward direction toward the front side of the vehicle  100 . A distal end  231  of the first external refrigerant pipe  230  is inserted in a through-hole  211  provided in the case  210  (i.e., the through-hole  211  provided in a wall (an outer wall) of the case  210 , the wall defining an external shape of the case  210 ), from the outside of the case  210 . In the through-hole  211 , the distal end  231  of the first external refrigerant pipe  230  is connected to the gasket  239 . The distal end  231  of the first external refrigerant pipe  230  is connected to the first internal refrigerant pipe  228  via the gasket  239 . A refrigerant pipe that includes the first external refrigerant pipe  230  and the first internal refrigerant pipe  228  extends through the through-hole  211  (in other words, the refrigerant pipe that includes the first external refrigerant pipe  230  and the first internal refrigerant pipe  228  extends through the case  210 , more specifically, extends through the wall of the case  210 ). Similarly to the first external refrigerant pipe  230 , the first internal refrigerant pipe  228  is inclined such that an axis of the first internal refrigerant pipe  228  extends obliquely downward toward the front side of the vehicle  100 . That is, the refrigerant pipe that includes the first external refrigerant pipe  230  and the first internal refrigerant pipe  228  extends obliquely downward toward the front side of the vehicle  100 . The cooler  220  is also inclined such that a refrigerant channel therein extends obliquely downward toward the front side of the vehicle  100 . 
     A flange  232  is provided at a distal end of a body  234  of the first external refrigerant pipe  230 . The flange  232  contacts a side surface of the case  210 . Although not shown, the flange  232  is fixed to the case  210  by a bolt. On an opposite side of the flange  232  from the case  210 , a notch  236  is provided on an outer surface of the body  234  of the first external refrigerant pipe  230 . 
     The notch  236  of the first external refrigerant pipe  230  is formed on the outer surface of the body  234 . In the body  234 , at a position near the flange  232 , the notch  236  extends linearly along the entire outer periphery of the body  234 . In other words, the notch  236  is a groove that is located outside the case  210  and extends along the entire outer periphery of the first external refrigerant pipe  230 . 
       FIG. 6  is an explanatory view showing an example of a state where the body  234  of the first external refrigerant pipe  230  is broken. The state in  FIG. 6  is a state where a collision load IM is applied to the electric power control unit  200  in  FIG. 5  from the front side and the body  234  is thereby broken at the notch  236 . The body  234  is thinner at the notch  236  extending along the entire circumference (i.e., the entire outer periphery) of the body  234  than at other portions (i.e., at the rest of the body  234 ), that is, the thin portion of the body  234  extends along the entire circumference (i.e., the entire outer periphery) of the body  234 . In other words, the body  234  is thinnest at the notch  236 . Accordingly, when the collision load IM is applied to the body  234  from the front side, the body  234  of the first external refrigerant pipe  230  can be broken at the notch  236  by concentrating stress on the notch  236 . At the time, due to a gravitational force, a refrigerant W that remains in the cooler  220  flows out of the case  210  of the electric power control unit  200  through the opened notch  236  (i.e., the broken notch  236 ) of the body  234 . 
     According to the embodiment that has been described so far, when the collision load IM, which is generated at the time of a collision of the vehicle  100 , is applied to the first external refrigerant pipe  230 , the body  234  is opened preferentially at the notch  236 . Thus, the refrigerant W can be discharged from the cooler  220  to the outside of the case  210  through the opened notch  236  of the first external refrigerant pipe  230 . Thus, it is possible to prevent the refrigerant W from leaking in the case  210 . As a result, it is possible to prevent damage to the electrical components  300 , which is caused by the leakage of the refrigerant W, at the time of the collision of the vehicle  100 . 
     In addition, in the vehicle  100  that includes the electric power control unit  200 , the body  234  of the first external refrigerant pipe  230  projects in a direction of gravity (more specifically, obliquely downward) from the case  210 . The cooler  220  is located above the notch  236 . Thus, when the collision load IM, which is generated at the time of the collision of the vehicle  100 , is applied to the first external refrigerant pipe  230 , the refrigerant W is guided from the cooler  220  to the body  234  by the gravitational force. Thus, the refrigerant W can be further effectively discharged from the cooler  220  to the outside of the case  210  through the notch  236 . 
     Hereinafter, a second embodiment of the disclosure will be described.  FIG. 7  is a partial sectional view showing a detailed configuration of an electric power control unit  200 B in the second embodiment.  FIG. 8  is a sectional view showing a detailed configuration of a body  234 B of a first external refrigerant pipe  230 B that is seen along arrows VIII-VIII in  FIG. 7 . The electric power control unit  200 B in the second embodiment is the same as the electric power control unit  200  in the first embodiment except that the electric power control unit  200 B includes the first external refrigerant pipe  230 B instead of the above-described first external refrigerant pipe  230 . The first external refrigerant pipe  230 B in the second embodiment is the same as the first external refrigerant pipe  230  in the first embodiment except that the first external refrigerant pipe  230 B includes the body  234 B provided with a notch  236 B instead of the body  234  provided with the notch  236 . 
     The body  234 B of the first external refrigerant pipe  230 B is a cylindrical portion that projects to the outside of the case  210  from the flange  232 . The axis AX of the body  234 B extends obliquely downward toward the front side of the vehicle  100 . 
     The notch  236 B of the first external refrigerant pipe  230 B is formed on an outer surface of the body  234 B. On the outer surface of the body  234 B, the notch  236 B is formed in a portion that faces downward. The notch  236 B extends linearly in a projected direction of the body  234 B. In other words, the notch  236 B extends linearly along the axis AX of the body  234 B of the first external refrigerant pipe  230 B. 
       FIG. 9  is an explanatory view showing an example of a state where the body  234 B of the first external refrigerant pipe  230 B in the electric power control unit  200 B is broken.  FIG. 10  is a sectional view showing a detailed configuration of the body  234 B that is seen along arrows X-X in  FIG. 9 . A state in each of  FIG. 9  and  FIG. 10  is a state where the collision load IM is applied to the electric power control unit  200 B in  FIG. 7  from the front side and the body  234 B is thereby broken at the notch  236 B. The body  234 B is thinner at the notch  236 B extending linearly along the axis AX than at other portions (i.e., at the rest of the body  234 B), that is, the thin portion of the body  234 B extends linearly along the axis AX. In other words, the body  234 B is thinnest at the notch  236 B. Accordingly, when the collision load IM is applied to the body  234 B from the front side, the body  234 B can be opened at the notch  236 B by concentrating the stress on the notch  236 B. At the time, due to the gravitational force, the refrigerant W that remains in the cooler  220  flows out of the case  210  through the opened notch  236 B of the body  234 B. 
     According to the second embodiment that has been described so far, when the collision load IM, which is generated at the time of the collision of the vehicle  100 , is applied to the first external refrigerant pipe  230 B, the body  234 B is opened preferentially at the notch  236 B. Thus, the refrigerant W can be discharged from the cooler  220  to the outside of the case  210  through the opened notch  236 B. Thus, it is possible to prevent the refrigerant W from leaking in the case  210 . As a result, it is possible to prevent the damage to the electrical components  300 , which is caused by the leakage of the refrigerant W, at the time of the collision of the vehicle  100 . 
     In addition, in the vehicle  100  that includes the electric power control unit  200 B, the notch  236 B is formed in the portion of the outer surface of the first external refrigerant pipe  230 B, the portion facing the direction of gravity (i.e., facing downward). The notch  236 B extends linearly in the direction in which the body  234 B projects. That is, the notch  236 B is provided on the lower surface of the first external refrigerant pipe  230 B, and extends along the axial direction of the first external refrigerant pipe  230 B. Thus, when the collision load IM, which is generated at the time of the collision of the vehicle  100 , is applied to the first external refrigerant pipe  230 B, the portion of the body  234 B, which faces the direction of gravity (i.e., extends obliquely downward toward the front side), is preferentially opened at the notch  236 B. Thus, the refrigerant W can be further effectively discharged from the cooler  220  to the outside of the case  210  through the opened notch  236 B. 
     Points to be noted with regard to the technique in the embodiments will be described. The first external refrigerant pipe  230  ( 230 B) and the first internal refrigerant pipe  228  ( 228 B) are connected to each other and correspond to an example of the “refrigerant pipe”. The second internal refrigerant pipe  229  and the second external refrigerant pipe  240  are connected to each other and constitute another refrigerant pipe. The other refrigerant pipe may have the same configurations as the configurations of the first external refrigerant pipe  230  ( 230 B) and the first internal refrigerant pipe  228  ( 228 B). The same applies to the third external refrigerant pipe  250 . The technique disclosed in the present specification can be also applied to an electrical apparatus other than the electric power control unit. 
     The embodiments have been described so far in detail. However, they are merely illustrative and thus do not limit the scope of the disclosure. The scope of the disclosure includes various modifications and changes that are made to the above-described embodiments. In addition, the technical elements that are described in the present specification and the drawings demonstrate technical utility when used singly or in various combinations, and thus are not limited to the combinations described in the above-described embodiments. Furthermore, the techniques that are described in the present specification and the drawings achieve a plurality of objects simultaneously, and technical utility is provided by achieving at least one of the plurality of objects.