Servo valves

Claim 2

A servo valve of the kind in which: a. a first valve member is connected to a second valve member by a resilient element which can twist to allow relative angular movement between the two members which movement is proportional to the applied torque; and b. relative angular movement of the two members is used to control, via ports in the two members, the supply of pressurised hdraulic fluid to one of two outlets of the valve depending upon the direction of rotation of the first member relatively to the second member; is characterised in that; c. the ports are arranged so that in operation, i.e., when fluid is passing through the valve, there is a resultant radial pressure applied to the first member with respect to the second member which resultant pressure tends to urge the first member against the latter in order to prevent vibrations of the first member with respect to the second member.

Claim 3

A servo valve as claimed in claim 1 characterised in that a single set of ports is formed in one circumferential region of the first and second members and one or more flats is or are formed on the first member at a diametrically opposite region to contain hydraulic fluid the pressure of which will oppose that contained in or passing through the said ports to reduce the magnitude of the said resultant radial pressure.

Claim 4

A servo valve as claimed in claim 1 in which the first member comprises a rotor which is rotatable within the second member which comprises a sleeve, the port arrangements being as follows: a. the rotor has a first slot, which is connected to the exhaust of the valve and through which fluid is supplied from the inlet to the valve; b. two lands of the rotor on each side of the first slot are in register with two ports in the sleeve when there is no torque reaction between the rotor and the sleeve to allow equal amounts of fluid to pass through said ports to exhaust; c. second and thrid slots on opposite sides of the said lands to the first slot allow fluid to pass from a supply port in the sleeve to either one of the two ports to the mutual exclusion of the remaining port which is simultaneously brought into communication with the first slot to exhaust the latter; and d. substantially diametrically opposite the aforesaid arrangement of ports and slots is or one or more flats formed on the circumference of the rotor so that hydraulic fluid contained by the flats exerts a radial pressure on the rotor which opposes that exerted by the fluid in the aforesaid slots and ports.

Claim 5

A servo valve which has the following features: a. a rotor is rotatable within a sleeve which in turn is contained within a housing; b. the rotor is connected to the sleeve by a torsion bar so that rotation of the rotor will be transmitted to the sleeve by the torsion bar, and the torsion bar will allow the rotor to rotate relatively to the sleeve if a load is applied to the sleeve; c. the housing has a fluid inlet, a fluid exhaust and two fluid outlets; d. the rotor has three axially extending slots separated by two axially extending lands located at a first region of the periphery of the rotor, the middle slot being in communication with the exhaust of the valve; e. the sleeve has two ports which are in communication with the two outlets respectively and which are closed by the tWo lands when there is no torque reaction between the rotor and the sleeve but rotation of the rotor relatively to the sleeve results in the lands moving out of register with their associated ports to bring one of the latter into communication with the inlet of the valve and the other into communication with the exhaust of the valve; and f. one or more flats are formed on the rotor in a region substantially diametrically opposite the said first region so that hydraulic fluid contained by the slot or slots exerts a radial pressure on the rotor which opposes the radial pressure exerted by the fluid in the same slots and ports.

Claim 6

A servo valve which has the following features: a. a rotor is rotatable within a sleeve which in turn is contained within a housing; b. the rotor is connected to the sleeve by a torsion bar so that rotation of the rotor will be transmitted to the sleeve by the torsion bar, and the torsion bar will allow the rotor to rotate relatively to the sleeve if a load is applied to the sleeve; c. the housing has a fluid inlet, a fluid exhaust and two fluid outlets; d. the rotor has three axially extending slots separated by two axially extending lands located at a first region of the periphery of the rotor, the middle slot being in communication with the exhaust of the valve; e. the sleeve has two ports which are in communication with the two outlets respectively and which are closed by the tWo lands when there is no torque reaction between the rotor and the sleeve but rotation of the rotor relatively to the sleeve results in the lands moving out of register with their associated ports to bring one of the latter into communication with the inlet of the valve and the other into communication with the exhaust of the valve; and f. one or more flats are formed on the rotor in a region substantially diametrically opposite the said first region so that hydraulic fluid contained by the slot or slots exerts a radial pressure on the rotor which opposes the radial pressure exerted by the fluid in the same slots and ports.

Claim 7

A servo valve which has the following features: a. a first valve member is connected to a second valve member by a resilient element which can twist to allow relative angular movement between the two members which movement is proportional to the applied torque; b. relative angular movement of the two members is used to control, via ports in the two members, the supply of pressurized hydraulic fluid to one of two outlets of the valve depending upon the direction of rotation of the first member relative to the second member; c. a single set of ports is formed in one circumferential region of the first and second valve members and one or more flats is or are formed on the first valve member at a diametrically opposite region to said set of ports in order to contain hydraulic fluid , the pressure of which will oppose that contained in or passing through the said ports.

Claim 8

A servo valve which has the following features: a. a first valve member is connected to a second valve member by a resilient element which can twist to allow relative angular movement between the two members which movement is proportional to the applied torque; b. relative angular movement of the two members is used to control, via ports in the two members, the supply of pressurized hydraulic fluid to one of two outlets of the valve depending upon the direction of rotation of the first member relative to the second member; c. a single set of ports is formed in one circumferential region of the first and second valve members and one or more flats is or are formed on the first valve member at a diametrically opposite region to said set of ports in order to contain hydraulic fluid , the pressure of which will oppose that contained in or passing through the said ports.

Claim 9

A servo valve which has the following features: a. a rotor which is rotatable within a sleeve; b. a torsion bar connecting the rotor to the sleeve whereby rotation of the rotor can be transmitted to the sleeve; c. a first slot formed in the rotor through which fluid is adapted to be supplied through an inlet to the valve; d. two lands formed on the rotor on each side of the said first slot, the two said lands being in register with two ports in the sleeve when there is no torque reaction between the rotor and the sleeve to allow equal amounts of fluid to pass through said ports to exhaust; e. second and third slots formed on opposite sides of the said lands to the first slots, said second and third slots being adapted to allow fluid to pass from the supply port in the sleeve to either one of the two said ports to the mutual exclusion of the remaining port, the latter being simultaneously brought into communication with the first slot to exhaust the latter; f. one or more flats formed on the circumference of the rotor at points diametrically opposite the aforesaid arrangement of ports and slots; and g. means for supplying fluid to said flats to thus exert a radial pressure on the rotor which opposes that exerted by the fluid in the aforesaid slots or ports.

Claim 10

A servo valve which has the following features: a. a rotor which is rotatable within a sleeve; b. a torsion bar connecting the rotor to the sleeve whereby rotation of the rotor can be transmitted to the sleeve; c. a first slot formed in the rotor through which fluid is adapted to be supplied through an inlet to the valve; d. two lands formed on the rotor on each side of the said first slot, the two said lands being in register with two ports in the sleeve when there is no torque reaction between the rotor and the sleeve to allow equal amounts of fluid to pass through said ports to exhaust; e. second and third slots formed on opposite sides of the said lands to the first slots, said second and third slots being adapted to allow fluid to pass from the supply port in the sleeve to either one of the two said ports to the mutual exclusion of the remaining port, the latter being simultaneously brought into communication with the first slot to exhaust the latter; f. one or more flats formed on the circumference of the rotor at points diametrically opposite the aforesaid arrangement of ports and slots; and g. means for supplying fluid to said flats to thus exert a radial pressure on the rotor which opposes that exerted by the fluid in the aforesaid slots or ports.