Electric pump and cleaning device for on-vehicle optical sensor

Abstract

An electric pump includes a cylinder, a piston, a motor, and a discharge valve. The cylinder includes a valve port and a discharge port, which is in communication with the valve port. The discharge valve opens and closes the valve port. When the piston is moved forth to narrow a void in the cylinder, air is compressed in the cylinder. The discharge valve opens when operated by the piston that moves forth. The discharge valve opens and discharges compressed air from the valve port so that fluid including air is discharged from the discharge port.

1 . An electric pump comprising:
 a tubular cylinder including a valve port and a discharge port, which is in communication with the valve port, wherein inner and outer sides of the cylinder are in communication through the valve port;   a piston that is movable back and forth in the cylinder;   a motor that drives and moves the piston back and forth; and   a discharge valve that functions to open and close the valve port, wherein   when the piston is moved forth to narrow a void in the cylinder, air is compressed in the cylinder,   the discharge valve is configured to open when operated by the piston that moves forth, and   the discharge valve opens and discharges compressed air from the valve port so that fluid including air is discharged from the discharge port.   
     
     
         2 . The electric pump according to  claim 1 , wherein
 the discharge valve includes an operation projection that projects into the cylinder, and   the discharge valve is operated when the operation projection is pushed by the piston.   
     
     
         3 . The electric pump according to  claim 1 , wherein
 the cylinder includes a liquid inlet, and   washer liquid is drawn through the liquid inlet into a void between the valve port and the discharge port.   
     
     
         4 . The electric pump according to  claim 3 , wherein a fluid check valve is arranged in the liquid inlet to permit the washer liquid to flow into a void between the valve port and the discharge port and prevent reversed flow of the fluid. 
     
     
         5 . The electric pump according to  claim 3 , wherein a liquid reservoir that is capable of storing the washer liquid drawn through the liquid inlet is located between the valve port and the discharge port. 
     
     
         6 . The electric pump according to  claim 5 , wherein
 a holding valve is located in a portion of the liquid reservoir proximate to the discharge port, and   the holding valve prevents outflow of washer liquid from the discharge port when the discharge valve is closed, and the holding valve opens when the discharge valve opens.   
     
     
         7 . The electric pump according to  claim 5 , wherein the valve port, the liquid reservoir, and the discharge port are arranged along a straight line. 
     
     
         8 . The electric pump according to  claim 1 , further comprising a biasing member that biases the discharge valve to close,
 wherein the biasing member has characteristics set so as not to open the discharge valve with the compressed air.   
     
     
         9 . The electric pump according to  claim 1 , further comprising a speed reduction mechanism that reduces the speed of rotation produced by the motor and transmitted to the piston. 
     
     
         10 . An on-board optical sensor cleaning device comprising:
 an electric pump including
 a tubular cylinder including a valve port and a discharge port, wherein inner and outer sides of the cylinder are in communication through the valve port, 
 a piston that is movable back and forth in the cylinder, 
 a motor that drives and moves the piston back and forth, and 
 a discharge valve that functions to open and close the valve port, wherein 
 when the piston is moved forth to narrow a void in the cylinder, air is compressed in the cylinder, 
 the discharge valve is configured to open when operated by the piston that moves forth, and 
 the discharge valve opens and discharges compressed air through the valve port and from the discharge port; 
   a nozzle connected to the discharge port, wherein the nozzle includes an ejection port; and   a mixing member that connects the discharge port and the nozzle and includes a liquid inlet, wherein washer liquid is drawn through the liquid inlet,   wherein the on-board optical sensor cleaning device ejects fluid including air from the ejection port toward an external image capturing surface of an on-board optical sensor mounted on a vehicle to remove foreign material from the external image capturing surface.   
     
     
         11 . The on-board optical sensor cleaning device according to  claim 10 , wherein a liquid reservoir capable of storing the washer liquid drawn through the liquid inlet is located between the discharge port and the nozzle in the mixing member. 
     
     
         12 . The on-board optical sensor cleaning device according to  claim 11 , further comprising a washer pump that delivers washer liquid to the liquid reservoir through the liquid inlet,
 wherein the washer pump is driven at the same time as when the motor is driven and delivers washer liquid to the liquid reservoir before the discharge valve opens.   
     
     
         13 . The on-board optical sensor cleaning device according to  claim 11 , further comprising a washer pump that delivers washer liquid to the liquid reservoir through the liquid inlet,
 wherein the washer pump is driven for a preset time before the motor is driven.   
     
     
         14 . The on-board optical sensor cleaning device according to  claim 11 , further comprising a washer pump that delivers washer liquid to the liquid reservoir through the liquid inlet,
 wherein the washer pump is driven for a preset time after the discharge valve opens.   
     
     
         15 . The on-board optical sensor cleaning device according to  claim 10 , wherein
 the nozzle is configured to be moved by delivering pressure of fluid including air discharged from the electric pump,   the ejection port is movable to a cleaning position, where the ejection port is located proximate to an image capturing range center of the on-board optical sensor.