Motor-mounted internal gear pump and electronic device

Abstract

The present invention aims to provide a motor-mounted internal gear pump that is small-sized, less expensive and has high reliability, while utilizing a function of an internal gear pump that is suitable for high head. A motor-mounted internal gear pump has a pump section for sucking and discharging a liquid and a motor section for driving the same. The pump section has an internal rotor having teeth formed around its outer periphery, an external rotor having teeth formed around its inner periphery and a pump casing that accommodates both rotors and has a suction port for sucking a liquid and a discharge port for discharging a liquid. The motor section has a can that composes a part of the pump casing and formed of anon-magnetic material into a thin plate, a rotator arranged at the inside of the can for driving the external rotor or the internal rotor; and a stator arranged at the outside of the can for rotating the rotator.

1 . A motor-mounted internal gear pump provided with a pump section for sucking and discharging a liquid and a motor section for driving the pump section, wherein the pump section comprises: 
 an internal rotor having teeth formed around the outer periphery;    an external rotor having teeth, that are meshed with the teeth of the internal rotor, formed around the inner periphery; and    a pump casing that accommodates both rotors and has a suction port for sucking a liquid and a discharge port for    discharging a liquid, and    the motor section comprises:    a can that composes a part of the pump casing and formed of a non-magnetic material into a thin plate;    a rotator arranged at the inside of the can for driving the external rotor or the internal rotor; and    a stator arranged at the outside of the can for rotating the rotator.    
   
   
       2 . The motor-mounted internal gear pump according to  claim 1 , wherein the rotator is made into a cylindrical shape and is fixedly disposed to the outer periphery of the external rotor so as to surround the outer periphery of the external rotor, the can is made into a thin cylindrical shape and surrounds the outer periphery of the rotator, and the stator is made into a cylindrical shape and arranged at the outside of the can.  
   
   
       3 . The motor-mounted internal gear pump according to  claim 1 , wherein the internal rotor is rotatably supported about a shaft that is fitted into its central hole, and the external rotor is rotatably supported by a part of the pump casing in which the external rotor is fitted into an inner peripheral face of a bracket section that projects in the shaft direction, whereby the rotator is fixed to the external rotor.  
   
   
       4 . The motor-mounted internal gear pump according to  claim 3 , wherein the bracket section is formed at both sides so as to project in the shaft direction, and the shoulder section of the pump casing arranged at both sides of the external rotor is fitted into the inner peripheral face of the bracket section projecting at both sides, whereby the external rotor is rotatably supported by the pump casing.  
   
   
       5 . The motor-mounted internal gear pump according to  claim 1 , wherein the motor section is composed of a DC brushless motor whose rotator is made of a permanent magnet, and magnetism detecting means having a function of detecting the passage of the permanent magnet is provided at the outside of the can, wherein a current control device is provided for controlling the current supplied to the stator of the DC brushless motor based upon the output of the magnetism detecting means.  
   
   
       6 . The motor-mounted internal gear pump according to  claim 1 , wherein the internal rotor and the external rotor are injection-molded from a synthetic resin material having a self-lubricating property, and the directions of drafts with this injection molding are reverse to each other in the state where both rotors are meshed with each other, wherein both rotors are meshed with each other such that the diameter of the internal tooth of the external rotor is increased in the direction in which the diameter of the external tooth of the internal rotor is increased.  
   
   
       7 . The motor-mounted internal gear pump according to  claim 1 , wherein the space where the internal rotor and the external rotor are accommodated is isolated from the outside by the casing including the can, except for the flow channel passing through the suction port and the discharge port, wherein a flow channel is provided through which at least a part of the liquid in the suction or discharge paths flows via the inner space of the can.  
   
   
       8 . The motor-mounted internal gear pump according to claim  1 , wherein the current control device is thermally brought in close contact with the casing.  
   
   
       9 . The motor-mounted internal gear pump according to  claim 1 , wherein a motor driving circuit provided with a power consumption detecting means is incorporated, and a control function is provided, this control function performing an operation with a speed more increased than a normal rotational speed by a limited period in case where it is determined that the electric power consumption immediately after the activation is smaller than a predetermined value, and that changes the increased speed to the normal rotational speed in case where it is determined that the electric power consumption exceeds the predetermined value.  
   
   
       10 . The motor-mounted internal gear pump according to  claim 1 , wherein the can is made of a non-magnetic member such as stainless steel or resin.  
   
   
       11 . An electronic device having mounted thereto a liquid cooling system provided with a motor-mounted internal gear pump claimed in any one of  claims 1  to  9 .