Abstract:
A motor pump includes a motor, a controller and an impeller assembly. The motor has a motor casing with a first end. The controller is operative to control rotation of the motor. The impeller assembly is operably connected to the motor and is enclosed within a pump casing that is connected to the first end of the motor. The pump casing includes a chamber sized to a accommodate the controller.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to a motor pump for supplying and discharging fluid such as water and the like. 
     2. Description of Related Art 
     In general, many motor pumps have a pump unit mounted to the extreme end of a motor shaft projecting from a motor casing through a seal member. Some motor pumps employ a so-called &#34;brushless electric motor&#34; having a stator coil disposed at an inner periphery of a motor casing as a motor unit. Conventionally, this type of motor pump has a motor unit as shown in FIG. 3 that includes a motor shaft 17 projecting from a motor casing 16 as well as an accommodation chamber 19. A controller 18 for controlling a magnetic field of the stator coil is disposed within the accommodation chamber 19 that is located in a base end of the motor casing 16. For simplicity of illustration, the pump unit is not mounted to an end of the motor shaft 17 in FIG. 3. 
     Since the conventional motor pump must cope with heat generated by the controller 18, the motor pump must cool the controller 18 by having a large radiation fin 19a formed in the accommodation chamber 19. However, since the accommodation chamber 19 requires space for forming the radiation fin 19a in addition to an intrinsically necessary space required for this arrangement, this design prevents the reduction of weight and size of the motor pump. Further, when the radiation fin 19a is intended to dissipate heat generated by the motor unit, the size of the motor pump is further increased. Thus, there is a problem associated with reduction of weight and size of the motor pump when the radiation fin 19a is used to cool, i.e. dissipate heat, generated by the controller 18 and/or the motor unit. The present invention resolves this problem. 
     SUMMARY OF THE INVENTION 
     According to the present invention made to solve the above problems taking the aforesaid circumstances into consideration, a motor pump has a pump casing mounted to an end surface of a motor casing whereby an accommodation chamber for accommodating a controller for controlling the drive of a motor is disposed on the pump casing. 
     With this arrangement, the heat radiated from the accommodation chamber can be cooled by a fluid flowing in the pump without the need of a radiation fin or other member exclusively used for cooling. Now, the weight and size of the motor pump can be reduced. In the present invention arranged as described above, the motor may be a brushless motor. 
     In the present invention, the accommodation chamber is located adjacent to an inflow passage and an outflow passage of a pump casing disposed on the motor casing. With this arrangement, the accommodation chamber can be cooled by the fluid flowing through the inflow and outflow passages, so that a radiation fin or other member exclusively used for cooling the accommodation chamber need not be provided. 
     In the present invention, the accommodating chamber may be positioned between the inflow passage and the outflow passage of the pump casing so that cooling of the accommodation chamber can be more enhanced. 
     Further, according to the present invention, the motor shaft projecting portion of the motor casing is formed with a recess portion and a pump member can be received by the recess portion of the casing, which, in turn, the weight and size of the motor pump can be reduced. 
     Additionally, according to the present invention, the core shaft of the motor casing is journaled at the recess portion of the casing through a bearing interposed between the recess portion of the casing which is received in a core recess portion formed to a rotor core connected to the core shaft. Thus, the weight and size of the motor pump can be further reduced. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross sectional view of a motor pump of the present invention; 
     FIG. 2 is a perspective view of the motor pump of the present invention; and 
     FIG. 3 is a perspective view of a conventional motor pump shown without a pump unit. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Next, a preferred embodiment of the present invention will be described based on the drawings. In the drawings, a brushless motor constituting a motor pump 1 pumps, for example, water or other types of fluid. Although water is used throughout the description of the preferred embodiment, one of ordinary skill in the art would appreciate that any fluid, particularly a liquid fluid, could be used as a substitute therefor. The brushless motor 1 includes a motor casing 2 which is described in more detail below, a core shaft 3 journaled by the casing 2, a rotor core 4 integrally connected with the core shaft 3 and having a permanent magnet 4c fixedly secured to the outer periphery thereof, a stator coil 5a wound around a stator core 5 disposed within the inner periphery of the motor casing 2 and a controller 6 for controlling the magnetic field of the stator coil 5a similar to conventional brushless motors. 
     The motor casing 2 is composed of a bottomed cylindrical case main body 7 composed of a cylindrical portion 7a to which the stator core 5a is fixed and an end surface portion (bottom portion) 7b formed at an end of the cylindrical portion 7a and an end bracket 8 for covering an opened end of the case main body 7 on a base end side thereof. A recess portion 7c which is recessed inwardly toward the center of the motor in a stepwise manner is formed at the end surface portion 7b, a cylindrical journal 7d projects from an inside end edge of the recess portion 7c toward the rotor core 4, an end of the journal 7d on a side of the rotor core 4 is inserted into a core recess portion 4a formed to the rotor core 4 and a bearing 4b is interposed between an inner cylindrical surface of the journal 7d and an outer periphery of the core shaft 3 in a state whereby it overlaps the core recess portion 4a. 
     Note, a base end of the core shaft 3 is journaled by an end bracket 8 through a bearing 8a. Numerals 9, 10 denote first and second seal elements for preventing water supplied and discharged by a motor unit 11, which is described below, from penetrating into the motor casing 2. Further, numeral 7e in the drawing denotes a first water discharge tube for discharging water infiltrating the motor casing 2 and numeral 7f denotes a second water discharge tube for discharging water infiltrating the second seal element 10. 
     A pump casing 12 is a component of the pump unit 11. The pump casing 12 is formed with a bottomed cylindrical shape with an opened end, an end edge of the opened end contacts the end surface portion 7b of the case main body 7 so as to accommodate an impeller 13 fixedly secured to the core shaft 3 projecting from the end surface portion 7b of the case main body 7 into the pump casing 12 as well as a water inflow passage 12a and a water outflow passage 12b are formed in an end surface of the pump casing 12 in an extending fashion. A water pump is arranged such that water supplied from a water source and drawn into the inflow passage 12a by an impeller 13 driven by the motor. Thereafter, water forcibly flows out from the outflow passage 12b. An accommodation chamber 12c is formed at the end surface of the pump casing 12 and is positioned in a vicinity between the inflow passage 12a and the outflow passage 12b. The controller 6 for controlling the magnetic field of the stator coil 5 is accommodated in the pump casing 12. The accommodation chamber 12c is sized so it does not extend beyond the inflow and outflow passages 12a, 12b as viewed along the axial direction, i.e. in the direction of the core shaft 3. Also, the accommodation chamber 12c is further sized so as not to project beyond the extreme ends of the inflow and outflow passages 12a, 12b in the radial direction relative to the core shaft 3. Thus, the accommodation chamber 12c is protected by the inflow and outflow passages 12a, 12b. 
     A cover 14 covers the accommodation chamber 12c and nipple elements 15 connect to each of the inflow and outflow passages 12a, 12b. 
     In the preferred embodiment of the present invention as described above, the rotor core 4 of the brushless motor 1 constituting the motor pump is rotated by controlling the magnetic field of the stator core 5a in response to a control command from the controller 6 to thereby drive the pump unit 11. In this preferred embodiment of the present invention, the controller 6 for controlling the drive of the brushless motor 1 is disposed in the accommodation chamber 12c formed in the pump casing 12. As a result, since the controller 6 is subjected to a cooling action achieved by water flowing through the pump unit 11 as a coolant (i.e., cooling water), a radiation fin need not be provided for cooling which differs from a conventional accommodation chamber disposed in the motor casing as shown in FIG. 3. Thus, the accommodation chamber 12c can be made compact. 
     As described above, the controller 6 for controlling the drive of the brushless motor 1 is disposed in the accommodation chamber 12c formed integrally in the pump casing 12 of the motor pump in which the present invention is embodied and subjected to cooling action by the water flowing in the pump. Further, since the accommodation chamber 12c is disposed between the inflow passage 12a and the outflow passage 12b, the accommodation chamber 12c is also subjected to the cooling action by water flowing thereby. As a result, the cooling effect of the controller 6 can be more enhanced. 
     Moreover, since the accommodation chamber 12c can be formed by effectively making use of a vacant space between the inflow passage 12a and the outflow passage 12b in the preferred embodiment of the present invention, the size of the motor pump can be reduced in the axial direction thereof and, thus, the weight of the motor pump can also be reduced. 
     In the preferred embodiment of the present invention, the core shaft 3 is journaled by the case main body 7 which is located at the position where it is received by the core recess portion 4a. This achieves an advantage of making the motor pump more compact by being combined with the recess portion 7c being formed at the end surface portion 7b of the case main body 7 so as to accommodate the seal elements 9, 10 and other components of the pump therein. 
     Further, since one side of the motor is enclosed by the end surface portion 7b of the case main body 7 and the pump casing 12 in the preferred embodiment of the present invention, a separate case member is not necessary to enclose the one side of the motor pump. Thus, the weight and size of the motor pump can be further reduced and the structure thereof can be simplified. Furthermore, since the brushless motor 1 itself is located adjacent to the pump unit only through the end surface portion 7b, it can be subjected to the cooling action of the flowing water.