Piezoelectric pump

Abstract

A pump body is provided including at least one inlet valve, at least one outlet valve, a substantially rigid top portion, a substantially rigid bottom portion, and collapsible side portions. The pump body also includes a base on or in the bottom portion and defining a rotational axis extending from the bottom portion. The pump body further includes a rotor shaft disposed along the rotational axis within the enclosure, a first end of the rotor shaft mechanically and rotatably coupled to the base, and a second end of the rotor shaft providing a cam surface for engaging the top portion and operable to cause motion of the top portion response to rotation of the rotor shaft. The pump body also includes at least one piezoelectric actuator engaging a surface of the rotor shaft, the piezoelectric actuator configured to cause the rotation of the rotor shaft.

1 . A pump body comprising at least one inlet valve, at least one outlet valve, a substantially rigid top portion, a substantially rigid bottom portion, and collapsible side portions, said pump body further comprising:
 a base on or in said bottom portion and defining a rotational axis extending from said bottom portion;   a rotor shaft disposed along said rotational axis within said enclosure, a first end of said rotor shaft mechanically and rotatably coupled to said base, and a second end of said rotor shaft providing a cam surface for engaging said top portion and operable to cause motion of said top portion response to rotation of said rotor shaft; and   at least one piezoelectric actuator engaging a surface of said rotor shaft, said piezoelectric actuator configured to cause said rotation of said rotor shaft.   
     
     
         2 . The pump body of  claim 1 , wherein said top portion further comprises an actuating member extending from a contact point on said top surface and physically contacting said cam surface. 
     
     
         3 . The pump body of  claim 2 , wherein said actuating member is L-shaped. 
     
     
         4 . The pump body of  claim 2 , wherein at least one portion of said actuating members extends transverse to said motion axis. 
     
     
         5 . The pump body of  claim 2 , wherein said contact point comprises a center of said top portion. 
     
     
         6 . The pump body of  claim 2 , wherein said actuating member comprises at least one bearing for said contacting of said cam surface. 
     
     
         7 . The pump body of  claim 2 , wherein said rotational axis extends through said contact point. 
     
     
         8 . The pump body of  claim 1 , wherein said piezoelectric actuator comprises:
 a piezoelement configured for generating a longitudinal vibration in a radial direction towards said rotational axis;   one or more flexible pushers, each of said flexible pushers having a first end mechanically coupled to said piezoelement and a second end extending in said radial direction and contacting said surface of said rotor shaft.   
     
     
         9 . The pump body of  claim 8 , wherein said piezoelement further comprises an annular piezoelement polarized along its thickness and retained on said base about said rotational axis. 
     
     
         10 . The pump body of  claim 9 , further comprising:
 a plurality of electrodes electrically coupled to upper and lower surfaces of annular piezoelement; and   a power supply configured to excite a first-order radial vibration mode in said annular piezoelement.   
     
     
         11 . The pump body of  claim 8 , wherein said flexible pushers are mechanically coupled to said upper surface of said annular piezoelement. 
     
     
         12 . The pump body of  claim 8 , wherein a pusher material for the pushers is selected from the group consisting of beryllium, copper, and plastic. 
     
     
         13 . The pump body of  claim 1 , wherein said inlet and outlet valves are located on the top portion of said enclosure. 
     
     
         14 . The pump body of  claim 1 , wherein at least the rotor, and the actuating member comprise non-magnetic materials. 
     
     
         15 . The pump body of  claim 14 , wherein said rotor comprises ceramic or glass. 
     
     
         16 . The pump body of  claim 14 , wherein the actuating member comprises non-ferrous metals. 
     
     
         17 . The pump body of  claim 1 , wherein said collapsible side portions comprise one or more elbows. 
     
     
         18 . The pump body of  claim 1 , wherein said base comprises an axial guide portion extending from said base for said coupling of said rotor shaft. 
     
     
         19 . A pump comprising at least one inlet valve, at least one outlet valve, a substantially rigid top portion, a substantially rigid bottom portion, and collapsible side portions, said pump further comprising:
 a base on or in said bottom portion and defining a rotational axis extending from said bottom portion;   a rotor shaft disposed along said rotational axis within said enclosure, a first end of said rotor shaft mechanically and rotatably coupled to said base, and a second end of said rotor shaft providing a cam surface for engaging said top portion and operable to cause motion of said top portion response to rotation of said rotor shaft;   an annular piezoelement polarized along its thickness and having opposing upper and lower surfaces and inner and outer rim surfaces, said annular piezoelement retained on said base about said rotational axis;   one or more flexible pushers, each of said flexible pushers having a first end mechanically coupled to said annular piezoelement and a second end extending radially to contact said rotor shaft; and   a power supply configured to excite a first-order radial vibration mode in said annular piezoelement,   wherein responsive to said exciting of said first-order vibration mode in said annular piezoelement, said flexible pushers cause a rotation of said rotor shaft.   
     
     
         20 . The pump of  claim 19 , wherein said flexible pushers are mechanically coupled to a portion of said annular piezoelement on or near one of said inner and outer rim surfaces. 
     
     
         21 . A reciprocating piezoelectric drive system comprising:
 a rotor shaft having an axis of rotation aligned with said shaft;   a base configured for supporting said rotor shaft along said axis of rotation;   at least one piezoelectric actuator configured to apply a rotational force on said rotor shaft transverse to said axis of rotation when said piezoelectric actuator is electrically excited;   a cam surface defined on a portion of said rotor shaft; and   a cam follower which engages said cam surface and configured so that a rotation of said rotor shaft causes a reciprocating linear motion of said cam follower.   
     
     
         22 . The reciprocating piezoelectric drive system according to  claim 21 , wherein said cam surface is aligned transverse to said axis of rotation. 
     
     
         23 . The reciprocating piezoelectric drive system according to  claim 22 , wherein said cam surface is an end face of said rotor shaft transverse to said axis of rotation. 
     
     
         24 . The reciprocating piezoelectric drive system according to  claim 21 , further comprising a bellows, said cam follower mechanically coupled to a first rigid portion of said bellows such that said reciprocating motion causes an internal chamber of said bellows to increase and decrease in volume. 
     
     
         25 . The reciprocating piezoelectric drive system according to  claim 24 , further comprising an inlet valve and an outlet valve in fluid communication with said internal chamber of said bellows. 
     
     
         26 . The reciprocating piezoelectric drive system according to  claim 25 , wherein said rotor shaft and cam follower are disposed within said internal chamber of said bellows. 
     
     
         27 . The reciprocating piezoelectric drive system according to  claim 25 , at least one piezoelectric actuator configured to apply a rotational force on said rotor shaft transverse to said axis of rotation when said piezoelectric actuator is electrically excited. 
     
     
         28 . The reciprocating piezoelectric drive system according to  claim 21 , wherein said piezoelectric actuator comprises:
 a piezoelement configured for generating a longitudinal vibration in a radial direction towards said rotational axis;   one or more flexible pushers, each of said flexible pushers having a first end mechanically coupled to said piezoelement and a second end extending in said radial direction and contacting said surface of said rotor shaft.   
     
     
         29 . The reciprocating piezoelectric drive system according to  claim 28 , wherein said piezoelement further comprises an annular piezoelement polarized along its thickness and retained on said base about said rotational axis. 
     
     
         30 . The reciprocating piezoelectric drive system according to  claim 29 , further comprising:
 a plurality of electrodes electrically coupled to upper and lower surfaces of annular piezoelement; and   a power supply configured to excite a first-order radial vibration mode in said annular piezoelement.   
     
     
         31 . The reciprocating piezoelectric drive system according to  claim 8 , wherein said flexible pushers are mechanically coupled to said upper surface of said annular piezoelement.