High frequency response servo valve

Claim 2

An electrohydraulic servo valve comprising a valve body having an elongated opening therethrough and including passages extending therein transversely of the opening therethrough through which hydraulic fluid is metered, a metering sleeve positioned within the opening through the valve body member having transverse openings therein through which hydraulic fluid is metered into and out of the passages, an elongated spool valve positioned within the metering sleeve for axial movement therein to meter the hydraulic fluid through the openings in the sleeve into and out of the passages, diaphragm biasing means positioned over the opposite ends of the opening through the valve body and supported by the valve body, separate force transfer members positioned between each diaphragm biasing means and a corresponding end of the spool valve without being connected to either the spOol valve or biasing means to transfer only compressive forces therein between the spool and biasing means for moving the spool valve within the metering sleeve in accordance with the movement of the diaphragm biasing means, means for adjusting the initial compressive forces in the force transfer members, a voice coil secured to at least one of the diaphragm biasing means for movement therewith, permanent magnet means carried by the valve body positioned adjacent the voice coil for causing movement of the voice coil in accordance with an electrical signal passed through the voice coil, and means for equalizing the hydraulic pressure on both sides of the diaphragm biasing means and the voice coil.

Claim 3

Structure as set forth in claim 1 wherein the diaphragm biasing means are perforate to provide passage of hydraulic fluid therethrough and means are provided in the valve body for connecting the hydraulic fluid adjacent both of the diaphragm biasing means.

Claim 4

Structure as set forth in claim 1 wherein the permanent magnet means includes a cylindrical permanent magnet positioned concentrically of and positioned axially and radially outwardly of the voice coil, a soft iron core having a T-shaped longitudinal cross section the stem of which is positioned within the voice coil and the crossbar of which is engaged with one end of the cylindrical permanent magnet and a cylindrical soft iron member positioned radially outwardly of and concentric with the voice coil one end of which is in engagement with the other end of the cylindrical permanent magnet whereby the soft iron members and the cylindrical permanent magnet define a cylindrical chamber at one end of the voice coil, and passages in the stem of the one soft iron core providing communication between the other end of the voice coil and the cylindrical chamber at the one end of the voice coil whereby hydraulic fluid pressure is equalized on both ends of the voice coil.

Claim 5

Structure as set forth in claim 1 wherein the means for adjusting the initial compressive forces in the force transfer members comprises an adjusting screw carried by each of the diaphragm biasing means centrally thereof in engagement with the separate force transfer members.

Claim 6

An electrohydraulic servo valve comprising a valve body having an elongated opening therethrough and including passages therein transversely of the opening therethrough through which hydraulic fluid is metered, an elongated spool valve positioned within the opening for axial movement therein to meter the hydraulic fluid through the opening in the valve body into and out of the passages, diaphragm biasing means positioned over the opposite ends of the opening through the valve body and supported by the valve body, separate force transfer members positioned between each diaphragm biasing means and a corresponding end of the spool valve without being connected to either the spool valve or diaphragm biasing means to transfer only compressive forces therein between the spool valve and diaphragm biasing means for moving the spool valve within the opening in accordance with the movement of the diaphragm biasing means, means carried by the diaphragm biasing means and operable between the diaphragm biasing means and force transfer members for adjusting the initial bias between the diaphragm biasing means and spool valve, a voice coil secured to at least one of the diaphragm biasing means for movement therewith, permanent magnet means carried by the valve body positioned adjacent the voice coil for causing movement of the voice coil in accordance with an electrical signal passed through the voice coil, and means operably associated with the diaphragm biasing means and voice coil for equalizing the hydraulic pressure on both sides of the diaphragm biasing means and the voice coil.

Claim 7

An electrohydraulic servo valve comprising a valve body having an elongated opening therethrough and including passages therein transversely of the opening therethrough through which hydraulic fluid is metered, an elongated spool valve positioned within the opening for axial movement therein to meter the hydraulic fluid through the opening in the valve body into and out of the passages, diaphragm biasing means positioned over the opposite ends of the opening through the valve body and supported by the valve body, separate force transfer members positioned between each diaphragm biasing means and a corresponding end of the spool valve without being connected to either the spool valve or diaphragm biasing means to transfer only compressive forces therein between the spool valve and diaphragm biasing means for moving the spool valve within the opening in accordance with the movement of the diaphragm biasing means, means carried by the diaphragm biasing means and operable between the diaphragm biasing means and force transfer members for adjusting the initial bias between the diaphragm biasing means and spool valve, a voice coil secured to at least one of the diaphragm biasing means for movement therewith, permanent magnet means carried by the valve body positioned adjacent the voice coil for causing movement of the voice coil in accordance with an electrical signal passed through the voice coil, and means operably associated with the diaphragm biasing means and voice coil for equalizing the hydraulic pressure on both sides of the diaphragm biasing means and the voice coil.

Claim 8

Structure as set forth in claim 5, wherein the means for equalizing the hydraulic pressure on both sides of the diaphragm biasing means includes openings through the diaphragm biasing means and a passage in the valve body member for connecting hydraulic fluid adjacent both of the diaphragm biasing means.

Claim 9

Structure as set forth in claim 5, wherein the permanent magnet means includes a cylindrical permanent magnet positioned concentrically of and both axially and radially outwardly of the voice coil with respect to the spool valve, a soft iron core having a T-shaped longitudinal cross section the stem of which is positioned within the voice coil and the cross bar of which is engaged with one end of the cylindrical permanent magnet and a cylindrical soft iron member positioned radially outwardly of and concentric with the voice coil one end of which is in engagement with the other end of the cylindrical permanent magnet whereby the soft iron members and the cylindrical permanent magnet define a cylindrical chamber at one end of the voice coil and wherein the means for equalizing the hydraulic pressure on both sides of the voice coil includes passages in the stem of the one soft iron core providing communication between the other end of the voice coil and the cylindrical chamber at the one end of the voice coil.

Claim 10

Structure as set forth in claim 5, wherein the means for adjusting the initial bias between the spool valve and the diaphragm biasing means comprises adjusting screws carried by the diaphragm biasing means centrally thereof for movement transversely of the diaphragm biasing means in engagement with the ends of the force transfer members.

Claim 11

Structure as set forth in claim 8 and further including an opening in the valve body member adjacent one adjusting screw and plug means threadedly secured within the opening whereby the bias between the diaphragm biasing means and the spool may be adjusted on removal of the plug without further disassembly of the electrohydraulic servo valve.

Claim 12

An electrohydraulic servo valve comprising a cylindrical valve body member, a cylindrical opening extending axially through the valve body member, transverse passages passing through the valve body member in communication with the axial opening therethrough, a metering sleeve positioned in the opening for metering fluid between the transverse passages, a spool valve positioned within the metering sleeve for reciprocation therein to meter fluid into and out of the passages through the metering sleeve, circular perforate diaphragm biasing means secured to the opposite ends of the valve body member over the opening therein, a passage in the valve body member connecting the areas surrounding the diaphragm biasing means for equalizing hydraulic fluid pressure therein, an adjusting screw threadably received centrally of one of the biasing diaphragms, a second adjusting screw and a voice coil threadably received in and carried centrally of the other of said biasing diaphragms, separate force transfer members positioned between the opposite ends of the spool valve and the associated adjusting screws which are not secured to either the spool valve or adjusting screws so as to transfer only compressive forces therein between the biasing diaphragms and spool valve whereby the bias on the spool valve may be adjusted on adjustment of the adjusting screws, a valve body cap positioned over one end of the valve body member adjacent the one biasing diaphragm, and permanent magnet motor means positioned over the other end of the valve body member operably associated with the voice coil for movement of the voice coil and thus the spool valve in accordance with the electrical energy passed through the voice coil.

Claim 13

An electrohydraulic servo valve comprising a cylindrical valve body member, a cylindrical opening extending axially through the valve body member, transverse passages passing through the valve body member in communication with the axial opening therethrough, a metering sleeve positioned in the opening for metering fluid between the transverse passages, a spool valve positioned within the metering sleeve for reciprocation therein to meter fluid into and out of the passages through the metering sleeve, circular perforate diaphragm biasing means secured to the opposite ends of the valve body member over the opening therein, a passage in the valve body member connecting the areas surrounding the diaphragm biasing means for equalizing hydraulic fluid pressure therein, an adjusting screw threadably received centrally of one of the biasing diaphragms, a second adjusting screw and a voice coil threadably received in and carried centrally of the other of said biasing diaphragms, separate force transfer members positioned between the opposite ends of the spool valve and the associated adjusting screws which are not secured to either the spool valve or adjusting screws so as to transfer only compressive forces therein between the biasing diaphragms and spool valve whereby the bias on the spool valve may be adjusted on adjustment of the adjusting screws, a valve body cap positioned over one end of the valve body member adjacent the one biasing diaphragm, and permanent magnet motor means positioned over the other end of the valve body member operably associated with the voice coil for movement of the voice coil and thus the spool valve in accordance with the electrical energy passed through the voice coil.

Claim 14

Structure as set forth in claim 10 wherein the permanent magnet motor means includes a cylindrical permanent magnet positioned concentrically of and both axially and radially outwardly of the voice coil with respect to the spool valve, a soft iron core having a T-shaped longitudinal cross section the stem of which is positioned within the voice coil and the crossbar of which is engaged with one end of the cylindrical permanent magnet and a cylindrical soft iron member positIoned radially outwardly and concentrically of the voice coil one end of which is in engagement with the other end of the cylindrical permanent magnet whereby the soft iron members and the cylindrical permanent magnet define a cylindrical chamber at one end of the voice coil, and passages in the stem of the one soft iron core providing communication between the other end of the voice coil and the cylindrical chamber at the one end of the voice coil whereby hydraulic fluid pressure is equalized on both ends of the voice coil.