Patent Document

INCORPORATION BY REFERENCE 
       [0001]    The disclosure of Japanese Patent Application No. 2011-259387 filed on Nov. 28, 2011 including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    There has been known a heat exchange apparatus designed to cool, for example, a semiconductor device which generates heat when operating. The heat exchange apparatus is mounted with the semiconductor device on an outside surface of a heat exchanger body with a liquid coolant flowing therethrough, thus cooling the semiconductor device with the liquid coolant. This specification discloses an apparatus which exchanges heat between a heat carrier flowing through the heat exchanger body and a device disposed on the outside of the heat exchanger body. The heat carrier is not limited to liquid and may be a gaseous medium or an intermediate medium between gas and liquid. More specifically, the heat exchange apparatus of the invention may be a heat exchange apparatus for cooling devices or a heat exchange apparatus for heating devices. 
         [0004]    2. Description of the Related Art 
         [0005]    The heat exchange apparatus often requires exact detection of the temperature of the heat carrier. Particularly, in a case where a semiconductor device for regulating electric power supplied to a vehicle-mounted traction motor is cooled by heat exchange between the semiconductor device and the liquid coolant, it is extremely necessary to detect the temperature of the liquid coolant exactly. Furthermore, in a case where the temperature of the liquid coolant fluctuates, it is extremely necessary to instantaneously detect the temperature change. 
         [0006]    However, it is difficult to dispose a temperature sensor for detecting the heat carrier temperature within the heat exchanger body. The temperature sensor is normally disposed on the outside of the heat exchanger body. In the case where the temperature sensor is disposed on the outside of the heat exchanger body, various factors affect the output of the temperature sensor. In exact observation, the temperature of the heat carrier, the temperature of a wall of the heat exchanger body, and the temperature of a device exchanging heat with the heat carrier vary from one another. Various considerations must be given to the detection of the heat carrier temperature using the temperature sensor disposed on the outside of the heat exchanger body while eliminating the influences of the temperature of the device exchanging heat with the heat carrier. 
         [0007]      FIG. 3  and  FIG. 4  show a surrounding structure of a temperature sensor of a heat exchange apparatus disclosed in the description and the drawings of Japanese Patent Application No. 2010-268115 (JP 2010-268115). However, this patent application has not been laid open yet (note: Although this patent application was not yet laid open on Nov. 28, 2011 when the application of this invention was filed, this patent application was laid open afterward on Jun. 21, 2012 as Japanese Patent Application Publication No. 2012-119501 (JP 2012-119501 A)). The heat exchange apparatus includes a heat exchanger body  7  in which a top panel  8  is superposed on a bottom panel  6  to define a heat carrier passage  4  therebetween, A temperature sensor  18  is fixed to the heat exchanger body  7  as follows. The bottom panel  6  and the top panel  8  are formed with through-holes  6   a ,  8   a  at places of superposition, the through-holes  6   a ,  8   a  permitting a bolt  12  to penetrate therethrough. The bolt  12  is press-inserted into the through-hole  6   a  and fixed therein. A shank of the bolt  12  penetrates through the through-hole  8   a  of the top panel  8 . The temperature sensor  18  is fixed to a temperature sensor support board  16 . The temperature sensor support board  16  is formed with a through-hole  16   a  to permit the shank of the bolt  12  to penetrate therethrough. The shank of the bolt  12  is inserted through the through-hole  16   a  of the temperature sensor support board  16  and a nut  14  is screwed on a tip of the bolt  12 , whereby the temperature sensor support board  16  is clamped and fixed between the nut  14  and the top panel  8 . The temperature sensor  18  is fixed at a position to face the heat carrier passage  4  via the top panel  8 . 
         [0008]    A heat exchange apparatus mounted with a temperature sensor is also disclosed in Japanese Patent Application Publication No, 2002-305010 (JP 2002-305010 A). The heat exchange apparatus of JP 2002-305010 A employs a logic plate having the temperature sensor embedded in the plate. 
         [0009]    The temperature sensor fixing technique shown in  FIG. 3  and  FIG. 4  has a problem in detecting the temperature of the heat carrier without response delay,  FIG. 3  shows the temperature sensor  18  which is fixed at the position to face the heat carrier passage  4  via the top panel  8 . However, the temperature sensor  18  is not in intimate contact with the top panel  8 . More exactly, an area of the temperature sensor support board  16  that covers a bottom face of the temperature sensor  18  is not in intimate contact with the top panel  8 . Therefore, the amount of heat transferred along a heat transfer passage going from the heat carrier in the heat carrier passage  4 →the top panel  8 →the temperature sensor  18  is unexpectedly small. Measurement results actually show that the amount of heat transferred along a heat transfer passage going from the heat carrier in the heat carrier passage  4 →the top panel  8 →the bolt  12 →the temperature sensor support board  16 →the temperature sensor  18  is rather greater than the above amount of heat. It was found that the latter heat transfer passage has less heat resistance because the bolt  12  and nut  14  bring the top panel  8  and the temperature sensor support board  16  into intimate contact at areas around the bolt  12  and nut  14 . 
         [0010]    According to the temperature sensor fixing technique shown in  FIG. 3  and  FIG. 4 , the heat transfer passage, as the main heat transfer passage, going from the heat carrier in the heat carrier passage  4 →the top panel  8 →the bolt  12 →the temperature sensor support board  16 →the temperature sensor  18  has such a long passage length that it takes a long time for temperature change of the heat carrier to be transferred to the temperature sensor  18 . In the temperature sensor fixing technique shown in  FIG. 3  and  FIG. 4 , response delay during the measurement of temperature is not negligible. The heat is transferred to the bolt  12  not only from the top panel  8  but also from the bottom panel  6  while the bottom panel  6  is in contact with a wall of a casing  2 . The temperature of the heat carrier differs from that of the wall of the casing  2 . According to the temperature sensor fixing technique shown in  FIG. 3  and  FIG. 4 , it is also found that the temperatures of the wall of the casing  2  and the like affect the results of temperature measurement. With the use of the logic plate disclosed in JP 2002-305010 A, it is still difficult to achieve the exact and quick detection of the temperature of the heat carrier. 
       SUMMARY OF THE INVENTION 
       [0011]    This specification discloses a heat exchange apparatus which is the result of improvement in the temperature sensor fixing technique and is capable of exact and quick detection of the temperature of the heat carrier (capable of outputting temperature measurement results following the temperature change of the heat carrier quick enough to make time delay negligible). 
         [0012]    According to one aspect of the invention, a heat exchange apparatus includes: a main body having a top panel and a bottom panel, the top panel superposed on top of the bottom panel to define a heat carrier passage therebetween; a temperature sensor fixed to a temperature sensor support board; and a fixing member for fixing the temperature sensor support board to the top panel and fixed to an outside surface of the top panel at a position to face the heat carrier passage via the top panel. According to the above heat exchange apparatus, the main heat transfer passage going from the heat carrier in the heat carrier passage→the top panel→the fixing member→the temperature sensor support board is minimized in the passage length. Hence, the temperature change of the heat carrier is quickly transferred to the temperature sensor. Further, the temperature sensor is less affected by temperatures of elements other than the heat carrier in the heat carrier passage. Thus, the temperature sensor can achieve the exact and quick detection of the temperature of the heat carrier. 
         [0013]    In the heat exchange apparatus according to another aspect of the invention, the temperature sensor may also be deviated from as position to face the heat carrier passage via the top panel as a result of fixing the fixing member to the position to face the heat carrier passage via the top panel. Even if the temperature sensor is deviated from the position to face the heat carrier passage via the top panel, the temperature sensor can achieve the exact and quick detection of the temperature of the heat carrier as long as the fixing member constituting the main heat transfer passage is fixed to the position to face the heat carrier passage via the top panel. 
         [0014]    In the heat exchange apparatus according to another aspect of the invention, the temperature sensor support board may be formed with a penetration portion. Further, the fixing member may include: a bracket fixed to the outside surface of the top panel at a position to face the heat carrier passage via the top panel; a shaft member fixed to the bracket and penetrating through the penetration portion formed in the temperature sensor support board; and a pressing member fixed to the shaft member penetrating through the penetration portion and pressing down the temperature sensor support board onto the bracket. Further, the shaft member may be fixed to the outside surface of the top panel at a position to face a central part of the heat carrier passage via the top panel. 
         [0015]    In the heat exchange apparatus according to another aspect of the invention, the bracket may also be fixed to the outside surface of the top panel by brazing. According to the above fixing by brazing, a braze alloy having a low melting point than the top panel and the bracket permits the bracket to be fixed to the top panel without melting the top panel nor the bracket. 
         [0016]    In the heat exchange apparatus according to another aspect of the invention, the top panel may also be flat and thinner than the bottom panel, the bottom panel may also be curved, the heat carrier may also be a liquid coolant, the penetration portion may also be a through-hole, the shaft member may also be a bolt, the pressing member may also be a nut, and the bottom panel may also abut on a wall of a casing. 
         [0017]    If a U-shaped notch, for example, is formed in the temperature sensor support board, the notch permits the shaft member to penetrate therethrough. Hence, the penetration portion formed in the temperature sensor support board need not be the through-hole. However, the penetration portion defined by an enclosed through-hole is easier to handle. What is required of the shaft member fixed to the bracket is that the shaft member is fixed to the bracket as fixing the temperature sensor to place. For example, the shaft member may be a bolt fixedly screwed in a screw hole formed in the bracket. In this case, if the bolt is screwed in the screw hole of the bracket, the head of the bolt serves as the pressing member for pressing down the temperature sensor support board onto the bracket. A structure where the bolt is screwed in the screw hole of the bracket so that the head of the bolt presses down the temperature sensor support board onto the bracket may be adopted. An alternative structure where the temperature sensor support board is pressed down onto the bracket by screwing the nut on the bolt projecting from the bracket may also be adopted. 
         [0018]    According to the heat exchange apparatus disclosed herein, the main heat transfer passage extending from the heat carrier in the heat carrier passage to the temperature sensor is notably reduced in the passage length. This provides for the exact and quick detection of the temperature of the heat carrier. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The features, advantages, and technical and industrial significance of this invention will be described in the following detailed description of example embodiments of the invention with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
           [0020]      FIG. 1  is a sectional view showing a temperature sensor fixing portion of a heat exchange apparatus according to an embodiment of the invention; 
           [0021]      FIG. 2  is a perspective view showing the temperature sensor fixing portion of the heat exchange apparatus according to the embodiment of the invention; 
           [0022]      FIG. 3  is a sectional view showing a temperature sensor fixing portion of a heat exchange apparatus according to Related Art; and 
           [0023]      FIG. 4  is a perspective view showing the temperature sensor fixing portion of the heat exchange apparatus according to Related Art. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0024]    The following is a list of main features of an embodiment of the invention to be described hereinbelow. 
         [0000]    Feature 1: A semiconductor device which generates heat when operating is disposed on an outside surface of a top panel of a heat exchanger body. A liquid coolant flows through the heat exchanger body. The semiconductor device is cooled with the liquid coolant.
 
Feature 2: An upper limit of output power from the semiconductor device is set according to the detected temperature of the liquid coolant thereby preventing the overheating of the semiconductor device. If the temperature detection has low accuracy, the upper limit must be set to a lower value because a substantial margin need be allowed for the upper limit. If the temperature detection is increased in accuracy, the margin allowed for the upper limit can be reduced so that the value of the upper limit can be increased. Increase in the accuracy of temperature detection leads to the expansion of operating range of the semiconductor device.
 
Feature 3: The semiconductor device regulates electric power supplied to a traction motor. The increase in the operating range of the semiconductor device leads to improvement of the travelling performance of the vehicle.
 
Feature 4: A wall of a casing accommodating an electronic device which generates heat when operating abuts on a bottom panel of the heat exchanger body.
 
         [0025]      FIG. 2  shows, in perspective, the vicinity of a heat carrier inflow pipe  22  of the heat exchanger body  7 .  FIG. 1  is a sectional view taken on the line I-I in  FIG. 2 . In  FIG. 1  and  FIG. 2 , a reference numeral  6  denotes a bottom panel; a reference numeral  8  denotes a top panel; a reference numeral  10  denotes a bracket; a reference numeral  12  denotes a bolt; a reference numeral  14  denotes a nut; a reference numeral  16  denotes a temperature sensor support board; a reference numeral  18  denotes a temperature sensor; a reference numeral  20  denotes a cable for transmitting an output from the temperature sensor to an external device. A reference numeral  4  denotes a heat carrier passage. A reference numeral  2  denotes a casing. A semiconductor device which generates heat when operating is fixed to an unillustrated area of an outside surface of the top panel  8  via a board formed of a material which has electrical insulative properties and high heat conductivity. Accommodated in the casing  2  is an electronic device which generates heat when operating. A liquid coolant flows through the heat carrier passage  4 , cooling the semiconductor device in contact with the top panel  8  as well as cooling a wall of the casing  2  in contact with the bottom panel  6 . The top panel  8  and the bottom panel  6  are formed from an aluminum alloy having high heat conductivity. In this embodiment, the heat exchanger body  7  is a cooler body, the heat carrier is the liquid coolant, and the heat carrier passage  4  is a liquid coolant passage. It is to be noted, however, that the fixing structure for the temperature sensor according to the embodiment is not only effective in cooling operation but also effective in heating operation using the heat carrier. Further, the temperature sensor fixing structure of the embodiment is also effective for a case where the heat carrier is gaseous. 
         [0026]    As shown in  FIG. 1 , the top panel  8  is flat while the bottom panel  6  is curved. The heat carrier passage  4  is formed by superposing the top panel  8  on the bottom panel  6 , followed by brazing overlapped opposite ends thereof. Overlapped areas of the top panel  8  and the bottom panel  6  are formed with a plurality of through-holes  24 . Bolts  25  penetrating through these through-holes are screwed into the wall of the casing  2  thereby fixing the heat exchanger body  7  to the casing  2 . Fixing the heat exchanger body  7  to the casing  2  brings the bottom panel  6  into intimate contact with the casing  2 . Indicated at  27  in the figure is a sleeve. 
         [0027]    A bracket  10  is brazed to the outside surface of the top panel  18  in order to fix the temperature sensor  18  to the top panel  8 . The bracket  10  is formed with a stepped through-hole  10   a  for receiving a head and a shank of the bolt  12 . The bolt  12  is press-inserted into the through-hole  10   a . The head of the bolt  12  is brazed to the top panel  8  in conjunction with brazing the bracket  10  to the outside surface of the top panel  8 . The shank of the bolt  12  extends upward from the bracket  10 . 
         [0028]    The temperature sensor  18  is a thermistor and is fixed to the temperature sensor support board  16 . The temperature sensor support board  16  is formed with a through-hole  16   a  which allows the shank of the bolt  12  to penetrate therethrough. After the shank of the bolt  12  is inserted through the through-hole  16   a  of the temperature sensor support board  16 , the nut  14  is screwed on the bolt  12 . When the nut  14  is screwed on the bolt  12 , the nut  14  presses down the temperature sensor support board  16  onto the bracket  10 , thus fixing the temperature sensor support board  16  to the top panel  8 . The bracket  10 , bolt  12  and temperature sensor support board  16  are formed from aluminum alloy having high heat conductivity. When the temperature sensor  18  is fixed to the top panel  8  via the temperature sensor support board  16  by using the bracket  10 , bolt  12  and nut  14 , the temperature sensor  18  is disposed at an area deviated from a position to face the heat carrier passage  4  via the top panel  8 . 
         [0029]    The bracket  10  and the bolt  12  fixed to the bracket  10  are disposed at positions to face the heat carrier passage  4  via the top panel  8 . As shown in  FIG. 1 , the bolt  12  is disposed at the position to face a central part of the heat carrier passage  4  via the top panel  8 . Furthermore, the top panel  8  is thinner than the bottom panel  6 . The main heat transfer passage from the heat carrier in the heat carrier passage  4  to the temperature sensor  18  goes from the heat carrier in the heat carrier passage  4 →the top panel  8 →the bolt  12 →the temperature sensor support board  16 →the temperature sensor  18 . The length of the heat transfer passage from the heat carrier in the heat carrier passage  4  to the temperature sensor  18  is minimized. The position of the through-hole  16   a  formed in the temperature sensor support board  16  is deviated from the fixing position of the temperature sensor  18 . Hence, the temperature sensor  18  is deviated from the position to face the heat carrier passage  4  via the top panel  8 . Even so, the temperature sensor  18  involves less detection error and detection delay because the main heat transfer passage is short in length. 
         [0030]    In the case shown in  FIG. 3 , the temperature sensor  18  faces the heat carrier passage  4  via the top panel  8 . At first glance, the structure of  FIG. 3  is more adapted for the exact and quick detection of the temperature of the heat carrier by means of the temperature sensor  18 . Actually, however, the structure of  FIG. 1  is more adapted for the exact and quick detection of the temperature of the heat carrier. The reason is that the temperature sensor  18  of  FIG. 1  or the temperature sensor  18  of  FIG. 3  is not in intimate contact with the bracket  10  nor the top panel  8  and hence, the amount of heat transmitted to the temperature sensor  18  is low. It was found that what is important is to reduce the length of the heat transfer passage including metal-to-metal intimate contact so as to be capable of transferring a large amount of heat. In the case shown in  FIG. 1 , the heat transfer passage from the heat carrier in the heat carrier passage  4  to the temperature sensor support board  16  is minimized in the length and hence, the structure of  FIG. 1  is adapted to detect the temperature of the heat carrier more exactly and quickly than the structure of  FIG. 3 . 
         [0031]    According to the embodiment, the heat transfer passage going from the heat carrier in the heat carrier passage  4 →the top panel  8 →the bolt  12 →the temperature sensor support board  16 →the temperature sensor  18  is spaced farther away from the wall of the casing  2  than the heat transfer passage shown in  FIG. 3 . Therefore, the influence that the heat of the wall of the casing  2  exerts on the temperature sensor  18  is reduced. With the additional effect of the reduced influence of the heat of the wall, the structure of the embodiment is adapted for the exact and quick detection of the temperature of the heat carrier by means of the temperature sensor  18 . 
         [0032]    In the above-described embodiment, the temperature sensor support board  16  is pressed down onto the bracket  10  by screwing the nut  14  on the bolt  12  anchored in the bracket  10 . Alternatively, a screw hole may be formed in the bracket  10  and the bolt may be screwed into the screw hole so as to permit the head of the bolt to press down the temperature sensor support board  16  onto the bracket  10 . A shaft member fixed in the bracket may be the shank of the bolt  12  anchored in the bracket  10  or the shank of the bolt screwed into the bracket  10 . A pressing member for pressing down the temperature sensor support board  16  on the bracket  10  may be the nut  14  or the head of the bolt. The combination of bolt and nut may be replaced by a rivet drivenly fixed in the bracket  10 . The temperature sensor support board  16  can be pressed down onto the bracket  10  with a head of the rivet. The shaft member may be formed integrally with the bracket. 
         [0033]    Although the specific examples of the invention have been described in detail, these examples are intended for purposes of illustration only and are not intended to limit the scope of the appended claims. The techniques disclosed in the scope of the claims include various modifications and changes of the above examples. Further, the technical elements described in this specification or shown in the drawings deliver technical utilities as used alone or in various combinations thereof and hence, are not limited to the combinations stated in the claims of this patent application. The techniques illustrated in this specification or the drawings are intended to achieve a plurality of purposes at a time and hence, deliver the technical utility by achieving any one of these purposes.

Technology Category: f