Problem determination device and control device for fluid device

Abstract

A problem determination device for a fluid device includes an object sensor for detecting an undesirable object in the fluid device and a determining section. The object sensor includes a detecting portion provided in the fluid device. The determining section determines that the fluid device has a problem when the object sensor detects an undesirable object. The problem determination device is capable of accurately determining that the fluid device has a problem at a relatively early stage of the problem.

1 . A problem determination device for a fluid device, the problem determination device comprising: 
 an object sensor for detecting an undesirable object in the fluid device, wherein the object sensor includes a detecting portion provided in the fluid device; and    a determining section, which determines that the fluid device has a problem when the object sensor detects an undesirable object.    
   
   
       2 . The problem determination device according to  claim 1 , wherein the fluid device is a piston type compressor having a crank chamber, and the detecting portion is provided in the crank chamber to detect an undesirable object in the crank chamber.  
   
   
       3 . The problem determination device according to  claim 1 , wherein the detecting portion includes a first contact and a second contact, and the object sensor detects an undesirable object when the object causes electric connection between the first contact and the second contact.  
   
   
       4 . The problem determination device according to  claim 3 , wherein the object sensor includes a detecting circuit having the first contact and the second contact, and the detecting circuit is closed when the object causes electric connection between the first contact and the second contact.  
   
   
       5 . The problem determination device according to  claim 3 , wherein the first and second contacts are each formed in a linear shape and extend parallel with each other, as spaced from each other at a predetermined interval.  
   
   
       6 . The problem determination device according to  claim 5 , wherein the detecting portion includes a substrate on which the first and second contacts are formed.  
   
   
       7 . The problem determination device according to  claim 3 , wherein the first and second contacts each include a plurality of linear portions, and the linear portions of the first contact and the linear portions of the second contact are arranged in an alternating manner.  
   
   
       8 . The problem determination device according to  claim 7 , wherein the detecting portion includes a substrate on which the first and second contacts are formed.  
   
   
       9 . The problem determination device according to  claim 1 , wherein the fluid device includes a housing assembly formed by a plurality of housing forming members securely fastened together by means of a through bolt, and the detecting portion is supported by the through bolt.  
   
   
       10 . The problem determination device according to  claim 9 , wherein the object sensor has a substrate having a cylindrical shape on which the detecting portion is formed, and the through bolt is passed through the substrate to support the detecting portion.  
   
   
       11 . The problem determination device according to  claim 1 , wherein the object sensor includes a magnet portion disposed in the fluid device for attracting an undesirable object to the detecting portion.  
   
   
       12 . The problem determination device according to  claim 1 , wherein the detecting portion is one of a plurality of detecting portions, and the object sensor includes the plurality of detecting portions.  
   
   
       13 . The problem determination device according to  claim 12 , wherein the determining section determines that the fluid device has a problem when at least two of the plurality of detecting portions detects an undesirable object.  
   
   
       14 . A control device for a variable displacement compressor, the control device comprising: 
 an object sensor for detecting an undesirable object in the compressor, wherein the object sensor includes a detecting portion provided in the compressor;    a determining section, which determines that the compressor has a problem when the object sensor detects an undesirable object; and    a displacement control section, which decreases the displacement of the compressor when the determining section determines that the compressor has a problem.    
   
   
       15 . The control device according to  claim 14 , wherein the compressor includes: 
 a suction pressure zone and a discharge pressure zone;    a control chamber, which connects to the suction pressure zone and the discharge pressure zone; and    a control valve, which adjusts the pressure in the control chamber so that the displacement of the compressor is increased when a drive current externally supplied to the control valve is increased and the displacement of the compressor is decreased when the drive current externally supplied to the control valve is decreased, and    wherein the detecting portion is connected to the control valve so that, when the object sensor detects an undesirable object, the drive current externally supplied to the control valve is decreased.