Abstract:
A controller assembly includes a plurality of controller units, and a heat dissipating unit interposed between the controller units. Male and female connectors are disposed in the controller units, and the connectors thereof are fitted to female and male connectors of the heat dissipating unit to thereby establish electrical contact therebetween. Upon driving electric actuators, heat generated in circuit boards of the controller units is dissipated to the exterior through a plurality of heat dissipating protrusions provided on the heat dissipating unit, so that heat generating sources of the circuit boards are cooled.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2016-036546 filed on Feb. 29, 2016, the contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The present invention relates to a controller, and more specifically, relates to a controller assembly, which enables a plurality of controllers to be arranged in a stacked condition, together with suitably releasing heat generated by loads connected to the controllers. 
         [0004]    Description of the Related Art 
         [0005]    Conventionally, a controller has been used as a robot control device to supply necessary electric power with respect to actuators for the purpose of extending and rotating an arm of the robot, as well as to transmit control signals for performing various operations. In Japanese Laid-Open Patent Publication No. 2007-175856, a robot controller has been proposed that expands the freedom in installation and placement of the robot without adversely affecting cooling efficiency concerning generation of heat due to operations of the robot. More specifically, a configuration is shown in which heat dissipating fins are arranged in close proximity to a circuit board that makes up a motor driver for driving a robot. 
       SUMMARY OF THE INVENTION 
       [0006]    The motor driver that is used in the robot controller of Japanese Laid-Open Patent Publication No. 2007-175856 is accommodated in the interior of a comparatively large scale main body housing made up from a pair of right and left side plates, a top plate, and a pair of front and rear side plates. Further, from the content depicted in  FIG. 1  of the patent document, it can be understood that the structure thereof is applicable to a single main controller. Consequently, there is no possibility for a main controller of this type to originate an idea of controlling a plurality of identical actuators within a limited space, and further, it is difficult to respond to demands for miniaturization. 
         [0007]    Moreover, the installation location for a small scale controller may not be the site where work actually is performed, and in many cases, such a small scale controller is installed in a power distribution board in which the electrical wiring therefor is centrally controlled. However, such a power distribution board does not have enough space for installation of the controller, even though the controller is small in scale, and even if the controller can be installed therein, it is difficult to add or change subsequent controllers. 
         [0008]    On the other hand, if the distance from the power distribution board to the actuators is long, not only is it difficult to arrange cables for supply of power for driving and transmission of control signals, but there also is a disadvantage in that losses occur during the supply of power. In order to avoid such an inconvenience, there has been a demand for a controller which can be disposed in the vicinity of a work site, without requiring the controller to be installed in a power distribution board. 
         [0009]    However, at the work site, a situation generally exists in which coolant liquids, dust, and the like are scattered about and undergo convection. Thus, a new demand has arisen, which requires the controller itself to be provided with a dust-proof and drip-proof structure. However, with a controller for supplying a large current in order to drive the actuators, since a large amount of heat is generated from the electronic components provided in the interior thereof, countermeasures must be taken separately in response to such generation of heat. 
         [0010]    For this reason, for example, if it is attempted to install a plurality of individual controllers within a limited space, it is necessary to consider anew such features as limitations on the installation interval, heat dissipating fans, ventilation openings, etc., and in actuality, it is difficult to achieve a compact size for such a controller and a saving in space. 
         [0011]    The present invention has been devised in order to solve at once problems of this type, and has the object of providing a controller assembly in which a plurality of individual controllers can be arranged in close proximity, and, by suitably releasing, to the exterior, heat that is generated from each of the controllers, cooling efficiency is increased, and the controller assembly can be made economical in terms of space and small in scale. 
         [0012]    In order to solve these problems, the present invention is characterized by a controller assembly including a plurality of controller units connected respectively to actuators, and a heat dissipating unit interposed between the controller units, wherein the heat dissipating unit includes a plurality of heat dissipating protrusions configured to dissipate heat that is generated by heat generating sources of the controller units, to the exterior. 
         [0013]    In accordance with this configuration, since the heat dissipating units are provided with the plurality of heat dissipating protrusions, which provide a widened heat dissipating area, it is possible to effectively dissipate, to the exterior, heat that is generated in each of the controller units, while in addition, since the controller units and the heat dissipating units are directly connected continuously to each other, useless space between both the controller units and the heat dissipating units is eliminated, and saving in space is achieved. 
         [0014]    In the controller assembly of the present invention, the heat dissipating unit may include connectors configured to be connected electrically to respective connectors of the controller units. 
         [0015]    In accordance with this configuration, since connectors for electrical connection with the connectors of the controller units are provided on the heat dissipating units, there is no need to consider the arrangement of external wiring, and an advantage is achieved in that bonding between the heat dissipating units and the controller units is strong and durable while the connection looks good and simple in appearance. 
         [0016]    In the controller assembly of the present invention, the heat dissipating unit may be attachable and detachable with respect to the controller units. 
         [0017]    In accordance with this configuration, since the heat dissipating units are engaged in a detachable manner with each of the controller units, without being limited in the number of the controller units and heat dissipating units that are connected together continuously, maintenance operations thereon are facilitated. 
         [0018]    In the controller assembly of the present invention, each of the controller units and the heat dissipating unit has a rectangular parallelepiped shape, a fitting projection is provided on one surface of each of the controller units and the heat dissipating unit, while a fitting recess is provided on another surface thereof, and the controller units and the heat dissipating unit are connected together continuously by the fitting projection of each of the controller units being fitted into the fitting recess of the heat dissipating unit, and the fitting projection of the heat dissipating unit being fitted into the fitting recess of the controller units. 
         [0019]    In accordance with this structure, since the controller units and the heat dissipating units are connected together continuously by male and female engagement of the fitting projections and the fitting recesses, assembly and disassembly is facilitated since both units can easily be engaged and disengaged with each other, while in addition, at the time that a malfunction is found in a specific controller unit connected continuously to the controller units, an operation can easily be performed to remove and verify only that particular controller unit. 
         [0020]    In the controller assembly of the present invention, a dust-proof or drip-proof sealing member may be provided around the periphery of the fitting projection of each of the controller units and the heat dissipating unit. 
         [0021]    In accordance with this configuration, it is possible to avoid a situation in which fine dust or water droplets that occur in a factory or the like become adhered to circuit boards of the controller units and cause a malfunction therein. 
         [0022]    In the controller assembly of the present invention, openings through which the connectors are exposed may be disposed respectively on inner sides of the fitting projection and the fitting recess of each of the controller units and the heat dissipating unit. 
         [0023]    In accordance with this configuration, since the openings are provided on inner sides of the fitting projections and the fitting recesses for thereby continuously connecting the controller units and the heat dissipating units, and the connectors are provided in facing relation to such openings, an advantage is realized in that the structure can be simplified and reduced in scale, without providing a special installation site for the connectors. 
         [0024]    In the controller assembly of the present invention, one surface of each of the controller units may include a heat dissipating plate, and another surface of the heat dissipating unit may be placed in contact with the heat dissipating plate. 
         [0025]    In accordance with this configuration, due to the fact that the heat dissipating plate, which constitutes one side surface of the controller unit, is disposed in proximity to a circuit board serving as a heat generating source, and the other surface of the heat dissipating unit is placed in direct contact with the heat dissipating plate, the generated heat can be dissipated more effectively and such heat can be transferred to the heat dissipating unit. 
         [0026]    In the controller assembly of the present invention, a heat dissipating sheet may be provided on the other surface of the heat dissipating unit, and the heat dissipating sheet may be placed in contact with the heat dissipating plate. 
         [0027]    In accordance with this configuration, the side plate of the controller unit is constituted by the heat dissipating plate, and further, the heat dissipating sheet provided on the heat dissipating unit is arranged by being pressed against the heat dissipating plate. Therefore, dissipation of heat generated in the controller units can be more effectively achieved. 
         [0028]    In the controller assembly of the present invention, a recessed portion may be provided on the other surface of the heat dissipating unit, and the heat dissipating sheet may be disposed in the recessed portion. 
         [0029]    In accordance with this configuration, since the heat dissipating sheet is disposed in the recessed portion, the thickness of the heat dissipating sheet does not present an obstacle to continuously connecting the heat dissipating units and the controller units. 
         [0030]    According to the present invention, a plurality of controller units can be arranged in close proximity, and together therewith, by suitably releasing, to the exterior, heat generated in each of the controller units by the heat dissipating units disposed in contact with the controller units, cooling efficiency in relation to the controller units can be increased, and it is possible to obtain a controller assembly that is economical in terms of space and small in scale. 
         [0031]    The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which a preferred embodiment of the present invention is shown by way of illustrative example. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIG. 1  is a perspective view showing a condition of use of a controller assembly according to the present invention; 
           [0033]      FIG. 2  is a perspective view showing a connection relationship between the controller assembly and an electric actuator; 
           [0034]      FIG. 3  is a perspective view showing a first controller unit that constitutes part of the controller assembly; 
           [0035]      FIG. 4  is a perspective view showing a condition in which the first controller unit is viewed from a side opposite to the direction depicted in  FIG. 3 ; 
           [0036]      FIG. 5  is a perspective view showing a heat dissipating unit that is used in the controller assembly; 
           [0037]      FIG. 6  is a perspective view showing a condition in which the heat dissipating unit is viewed from a side opposite to the direction depicted in  FIG. 5 ; and 
           [0038]      FIG. 7  is a front view of the heat dissipating unit illustrated in  FIGS. 5 and 6 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0039]    A preferred embodiment of a controller assembly according to the present invention will be presented and described in detailed below with reference to the accompanying drawings. 
         [0040]      FIG. 1  is a perspective view showing a condition of use of a controller assembly according to the present embodiment, and  FIG. 2  is a perspective view showing a state where the controller assembly according to the present embodiment is connected to an electric actuator. 
         [0041]    The controller assembly  10  according to the present embodiment basically is constituted by first controller units  20 , a second controller unit  60  that is shorter in a longitudinal direction than the first controller units  20 , an input unit  70  mounted on a side surface of the second controller unit  60 , heat dissipating units  80  joined to the first controller units  20 , and an end block  90  that is pressed against one of the heat dissipating units  80  from an outer side of the controller assembly to thereby tighten the first controller units  20 , the second controller unit  60 , the heat dissipating units  80 , and the input unit  70  together by non-illustrated tie rods. As can be understood easily from  FIG. 1 , the controller assembly  10  is installed in a desired location by a rail  100 . 
         [0042]      FIG. 2  is a perspective view showing a connected state where electric actuators  110   a,    110   b  are connected with the controller assembly  10 . Power and control signals are transmitted to the actuators from the first controller units  20  and the second controller unit  60 , whereby non-illustrated motors of the electric actuators  110   a,    110   b  are driven, so that tables  170   a,    170   b  are advanced or retracted through ball screws. 
         [0043]    The various constituent elements of the controller assembly  10 , which is constructed in the foregoing manner, will be described in detail below. 
         [0044]      FIG. 3  is a perspective view showing a first controller unit  20  that constitutes part of the controller assembly  10 . The first controller unit  20  has an elongated rectangular parallelepiped shape, and the first controller unit  20  contains therein a circuit board  22  on which electric circuit components are mounted for controlling operation of the electric actuators  110   a  and  110   b.  A first connector  24  is provided on the circuit board  22  in order to establish electrical connection with another first controller unit  20 . A portion of the circuit board  22  and the first connector  24  are exposed to the exterior from a heat dissipating plate  28  that constitutes part of a rectangular parallelepiped shaped housing  26  of the first controller unit  20 . More specifically, the heat dissipating plate  28  is made of a member that is excellent in terms of thermal conductivity, and has an elliptical opening  30  located below a central portion thereof. In addition, an elliptical shaped fitting projection  32  is provided in surrounding relation to the opening  30 . The first connector  24  is exposed to the exterior through the opening  30 . An elliptical shaped annular groove is disposed around the fitting projection  32 , and an o-ring  34  (sealing member) is fitted in the groove. 
         [0045]    As will be discussed later, the o-ring  34  serves to ensure a dust-proof and drip-proof state when the first controller unit  20  is joined to another first controller unit  20  or to the second controller unit  60 , and further, when the first controller unit  20  is joined to the heat dissipating unit  80 . More specifically, although the circuit board  22  is exposed to the exterior through the opening  30 , by the fitting projection  32 , when the first controller unit  20  is joined by the o-ring  34  with another controller unit or with a heat dissipating unit, introduction of dust and water vapor, which results in electrical damage to the circuit board  22 , is avoided. 
         [0046]    A cover  36  is disposed on an upper portion of the housing  26  and is capable of being opened and closed freely. By opening the cover  36 , it is possible to perform settings for a non-illustrated rotary switch or the like, and a switch group, not shown, which are attached to the circuit board  22 . A drive power source terminal  38   a  for supplying power to the electric actuators  110   a  and  110   b  shown in  FIG. 2 , a position information input terminal  38   b  for inputting output signals of sensors that detect the direction of movement and the movement distance of the tables  170   a  and  170   b  that make up the electric actuators  110   a  and  110   b,  and a contact input terminal  38   c  for inputting the outputs of auto switches or the like that are mounted on the electric actuators  110   a  and  110   b  are provided on one narrow side surface of the housing  26 . 
         [0047]    In  FIG. 3 , reference numerals  40   a  and  40   b  indicate light emitting elements for enabling visual confirmation of the operating states of the first controller unit  20  from the exterior, and reference numerals  42   a  and  42   b  indicate penetrating holes through which non-illustrated tie rods are inserted in order to integrate as a unitary structure the controller assembly  10  shown in  FIG. 1 . 
         [0048]    In this case, a rail insertion recess  44  through which the rail  100  is inserted is provided below the fitting projection  32  of the housing  26  that makes up the first controller unit  20 , and grooves  48   a,    48   b  into which flanges  46   a,    46   b  of the rail  100  are fitted are provided at both end portions of the rail insertion recess  44 . 
         [0049]    As shown in  FIG. 4 , on an opposite side from the heat dissipating plate  28  in the first controller unit  20 , an elliptical shaped fitting recess  50 , which is of the same size as the fitting projection  32 , is formed at a position corresponding to the opening  30  provided in the heat dissipating plate  28 , together with providing a second connector  52  which is positioned on an opposite side from the first connector  24 . More specifically, the fitting recess  50  serves as an opening corresponding to the opening  30 , and as with the first connector  24 , the second connector  52  is exposed to the exterior through the opening, which is the inner side of the fitting recess  50 . In the embodiment, assuming that the first connector  24  is a male connector, the second connector  52  functions as a female connector, and at a time that the first connector  24  is joined to another first controller unit  20 , an electrical connection is established by fitting with the female type second connector  52 . 
         [0050]    The second controller unit  60  basically is made up from the same constituent elements as the first controller unit  20 , but differs therefrom in that the length in the longitudinal direction of the second controller unit  60  is shorter than that of the first controller unit  20 . Accordingly, the same reference characters are used to designate the same constituent elements, and detailed description of such features is omitted. 
         [0051]    As shown in  FIG. 1 , the input unit  70  is connected to the second controller unit  60 . Power supply terminals  72   a  to  72   c  for inputting power are disposed in the input unit  70 . The input unit  70  belongs to the conventional art, and therefore, a detailed description of the input unit  70  will be omitted herein. 
         [0052]    Next, a description will be given of the heat dissipating unit  80 , which is disposed in the controller assembly  10  so as to be in close contact with the first controller unit  20 . 
         [0053]    As shown in  FIG. 5 , the heat dissipating unit  80  is made up from a rectangular parallelepiped body having substantially the same length in the horizontal direction and the vertical direction, although having a different thickness than that of the first controller unit  20 . Preferably, the heat dissipating unit  80  is formed integrally from a material that is excellent in terms of the heat dissipating properties thereof, for example, a metal material such as aluminum or copper, a resin material, etc. On one surface of the heat dissipating unit  80 , a large number of heat dissipating protrusions  92  having trapezoidal shapes in cross section are disposed continuously in alignment along lines in a horizontal direction and a vertical direction thereof. In the heat dissipating protrusions  92 , first heat dissipating grooves  94  are formed vertically between respective adjacent heat dissipating projections  92 , and second heat dissipating grooves  96  are further provided which extend in a horizontal direction (see  FIG. 7 ). Moreover, in order to provide a penetrating hole  98   a  corresponding to the penetrating hole  42   a  of the first controller unit  20 , a projection  99  is provided, which has the same height as that of the heat dissipating protrusions  92 , but is greater in length in the horizontal and vertical directions than the heat dissipating protrusions  92 . 
         [0054]    A rectangular connecting section  120  is provided on a side of the heat dissipating unit  80  where the heat dissipating protrusions  92  are disposed. Although the connecting section  120  may be formed integrally with the heat dissipating protrusions  92 , alternatively the connecting section  120  may be formed separately from the heat dissipating protrusions  92 . In that case, a space in which the connecting section  120  is fitted is provided in the heat dissipating unit  80 , such that the connecting section  120  may be incorporated therein. The connecting section  120  is provided with a penetrating hole  98   b  therein that corresponds to the penetrating hole  42   b  of the first controller unit  20 , together with a fitting projection  122  that corresponds to the fitting projection  32  of the first controller unit  20 . 
         [0055]    As with the case of the fitting projection  32 , an o-ring  124  (sealing member) is fitted around the periphery of the fitting projection  122 . A flat plate-shaped attachment section  128  is provided in an opening  126  located on an inner side of the fitting projection  122 . A third connector  130 , which corresponds to the first connector  24  of the first controller unit  20 , is disposed on the attachment section  128 . The first connector  24  and the third connector  130  have substantially the same structure, and therefore, detailed description of the third connector  130  is omitted. 
         [0056]      FIG. 6  is a view showing a configuration of the heat dissipating unit  80  on a side opposite to that depicted in  FIG. 5 . A fitting recess  132  having a size corresponding to the fitting recess  50  of the first controller unit  20  is provided on a rear surface side of the heat dissipating unit  80 . The inner side of the fitting recess  132  also serves as an opening corresponding to the opening  126  provided on an inner side of the fitting projection  122 . A fourth connector  134  is exposed to the exterior by projecting outwardly from the flat plate-shaped attachment section  128 , which is disposed on an inner side of the fitting recess  132 . The fourth connector  134  has a size and shape that correspond to those of the second connector  52  that is located on the rear side of the first controller unit  20 . A recessed portion  136  with a widely formed L-shape is disposed above the fitting recess  132  of the heat dissipating unit  80 . 
         [0057]    Next, a first heat dissipating sheet  138   a  and a second heat dissipating sheet  138   b  are arranged in the recessed portion  136 . The thicknesses of the first heat dissipating sheet  138   a  and the second heat dissipating sheet  138   b  are slightly greater than the depth of the recessed portion  136 , and the heat dissipating sheets  138   a,    138   b  exhibit excellent elasticity. The heat dissipating sheets  138   a,    138   b  are made of a material having high thermal conductivity, and as shown in  FIG. 1 , when the heat dissipating unit  80  and the first controller unit  20  are combined, the heat dissipating sheets  138   a,    138   b  are pressed against the heat dissipating plate  28 , receive heat from the circuit board  22  that is transmitted through the heat dissipating plate  28 , and transfer such heat to the side of the heat dissipating protrusions  92 . Therefore, preferably, the first heat dissipating sheet  138   a  and the second heat dissipating sheet  138   b  are arranged so as to correspond to positions where heat is most likely to be generated on the circuit board  22  in the interior of the first controller unit  20 . Alternatively, in the recessed portion  136 , only one heat dissipating sheet may be disposed at a position where heat is most likely to be generated. The third connector  130  corresponds to the first connector  24  of the first controller unit  20 , while the fourth connector  134  corresponds to the second connector  52 , and the first connector  24  and the third connector  130  have a male/female relationship with the second connector  52  and the fourth connector  134 . In  FIGS. 5 to 7 , reference numeral  140  indicates a recess corresponding to the rail insertion recess  44  of the first controller unit  20 , whereas reference numerals  142   a  and  142   b  indicate grooves corresponding to the grooves  48   a  and  48   b  of the rail insertion recess  44 . 
         [0058]    Lastly, a description will be given concerning the end block  90 . As can be understood from  FIG. 1 , the end block  90  is formed integrally from a metal material such as aluminum, a resin material, etc., having a thinner upper portion and a thicker lower portion, and is disposed on one side surface of the heat dissipating unit  80 . In particular, by covering the connecting section  120  of the heat dissipating unit  80 , the opening  126  thereof is closed. For this reason, although illustration thereof is omitted, preferably, a recess is provided having the same size as the opening  126  and into which the fitting projection  122  can be fitted. The end block  90  is provided with a rail insertion recess  150  for attachment to the rail  100 , and together therewith, rail attachment grooves  152   a,    152   b  into which the flanges  46   a,    46   b  of the rail  100  can be fitted are provided at both end portions of the rail insertion recess  150  in a widthwise direction thereof. In the figure, reference numeral  154   a  indicates a penetrating hole that corresponds to the penetrating hole  98   a  of the heat dissipating unit  80 , whereas reference numeral  154   b  indicates a penetrating hole that corresponds to the penetrating hole  98   b  of the heat dissipating unit  80 . 
         [0059]    The first controller units  20 , the second controller unit  60 , the input unit  70 , and the heat dissipating units  80 , which are constituted in the above manner, are assembled together in the following manner. 
         [0060]    At first, using non-illustrated screws or the like, the rail  100  is fixed in a location where the controller assembly  10  is to be assembled, and thereafter, the input unit  70 , the second controller unit  60 , the first controller unit  20 , the heat dissipating unit  80 , the first controller unit  20 , and the heat dissipating unit  80  are inserted onto the flanges  46   a,    46   b  of the rail  100  in this order, and finally, the end block  90  is inserted and positioned on the rail  100 . 
         [0061]    Next, tie rods (not shown) are inserted through the penetrating holes  154   a,    154   b  of the end block  90 , the penetrating holes  98   a,    98   b  of the heat dissipating units  80 , the penetrating holes  42   a,    42   b  of the first controller unit  20 , non-illustrated penetrating holes of the second controller unit  60 , and non-illustrated penetrating holes of the input unit  70 , and by screw-engagement of nuts on the opposite side, the first controller units  20 , the second controller unit  60 , the heat dissipating units  80 , the input unit  70 , and the end block  90  are fastened together in an integral fashion. 
         [0062]    In addition, ends of cables  160  are connected respectively to the drive power source terminal  38   a,  the position information input terminal  38   b,  and the contact input terminal  38   c  of the first controller unit  20 , and to the drive power source terminal  38   a,  the position information input terminal  38   b,  and the contact input terminal  38   c  of the second controller unit  60 , whereas the electric actuators  110   a,    110   b  are connected to other ends of the cables  160 . In this case, preferably, a relatively large scale electric actuator  110   a  is connected to the first controller unit  20 , whereas a relatively small scale electric actuator  110   b  is connected to the second controller unit  60 . Since the loads of the large scale electric actuator  110   a  and the small scale electric actuator  110   b  differ from each other, the amount of heat generated thereby also differs, and in accordance with such a difference in the amount of generated heat, a large scale heat dissipating unit is connected to the first controller unit  20 . On the other hand, with respect to the second controller unit  60  which generates a relatively small amount of heat, a heat dissipating unit is not mounted thereon, but rather, the input unit  70  is connected thereto directly. 
         [0063]    Upon completion of the preparatory steps described above, power is supplied to the power supply terminals  72   a  to  72   c  of the input unit  70 , control signals are transmitted via the first controller units  20  and the second controller unit  60 , and the electric actuators  110   a  and  110   b  are driven and controlled. More specifically, electrical power is supplied to the electric actuators  110   a  and  110   b  from the drive power source terminal  38   a,  and when non-illustrated motors thereof are driven, ball screws connected to the drive shafts of the motors undergo rotation, and by displacement of the ball nuts that are screwed onto the ball screws, the tables  170   a  and  170   b,  which are connected to the ball nuts, are displaced. The movement directions and the amount of movement of the tables  170   a  and  170   b  are detected by non-illustrated detection devices (sensors), information thereof is supplied from the position information input terminal  38   b  to the circuit boards  22  of the first controller unit  20  and the second controller unit  60 , and electrical processing is performed. As a result, the operating states of the electric actuators  110   a  and  110   b  can be grasped. 
         [0064]    When the electric actuators  110   a  and  110   b  are energized in this manner, due to the electric power that is supplied while the electric actuators  110   a  and  110   b  are controlled by the first controller unit  20  and the second controller unit  60 , heat is generated in the circuitry, etc., of the circuit boards  22 . Such generated heat, for example, is released to the exterior through the heat dissipating unit  80  disposed in contact with the heat dissipating plate  28 . More specifically, in the heat dissipating unit  80 , heat is released via the large number of heat dissipating protrusions  92 . In particular, since the heat dissipating protrusions  92  have trapezoidal shapes in cross section, the heat dissipation area is expanded, thus further enhancing the heat dissipating effect. 
         [0065]    In the foregoing manner, according to the present embodiment, the heat dissipating units are disposed on the controller units that drive and control the electric actuators, and the heat dissipating units efficiently dissipate heat that is generated in the controllers themselves, to the exterior. In addition, since a large number of controller units can be disposed continuously without restricting the number of controller units, the controller assembly, which is superior in terms of the heat dissipating effect, can be obtained without requiring an increase in the size of the installation space. 
         [0066]    Although a preferred embodiment of the present invention has been described in detail above, the controller assembly of the present invention is not limited to the present embodiment, and it goes without saying that various design modifications may be made to the embodiment without departing from the essential scope of the present invention as set forth in the appended claims. 
         [0067]    For example, according to the present embodiment, the heat dissipating protrusions of the heat dissipating unit are formed with trapezoidal shapes in cross section. However, without concern to the trapezoidal shapes thereof, it goes without saying that, also in the case that the heat dissipating area is enlarged by constituting the heat dissipating protrusions in truncated conical shapes or other polygonal shapes, the same advantages and effects can be obtained.