EP0171998A1 — Servo apparatus

Claim 1

Independent Claim 68 words

Servo valve apparatus comprising valve means (70) movable to open and close fluid communication between a first port (48 or 58) and a second port (56); input means (74) moving said valve means (70) in response to an input; and feedback means (78,84,86,80) opposing movement of said valve means (70) substantially as a first time derivative of fluid pressure at one of said first port and second port.

Claim 2

Dependent Claim 68 words

Servo valve apparatus comprising valve means (70) movable to open and close fluid communication between a first port (48 or 58) and a second port (56); input means (74) moving said valve means (70) in response to an input; and feedback means (78,84,86,80) opposing movement of said valve means (70) substantially as a first time derivative of fluid pressure at one of said first port and second port.

Claim 3

Dependent Claim 102 words

Apparatus as claimed in Claim 1 wherein said valve means comprises a valve member (60) sealingly co-operable with means (64) defining a seating surface, said valve member defining passage means (68) communicating said one port (56) with a third port (58) and opening in another seating surface (72), said valve apparatus further including another valve means (70) in a first relative position sealingly co-operable with said another seating surface (72) to close communication between said one port (56) and said third port (58), and means (74) operatively associating said input means (96) with said another valve means (70) for movement in unison.

Claim 4

Dependent Claim 205 words

Apparatus comprising a housing defining an inlet port (48), an outlet port (56), a vent port (58), and a flow path communicating each port with the others; a pair of relatively movable valve members movably received by said housing, a first (60) of said pair of valve members sealingly co-operating with said housing in a first position (64) to close fluid communication between said inlet port (48) and said outlet port (56), said first valve member (60) moving to a second position opening fluid communication between said inlet port (48) and said outlet port (56); the second (70) of said pair of valve members in a first position sealingly co-operating with said first valve member (60) to close fluid communication between said outlet port (56) and said vent port (58), said second valve member (70) moving to a second position opening communication between said outlet port (56) and said vent port (58); means (74) for moving either selected one of said pair of valve members respectively to said second position thereof; and means (78) for urging said selected one of said pair of valve members toward the respective first position thereof substantially as a first time derivative of fluid pressure at said outlet port (56).

Claim 5

Dependent Claim 205 words

Apparatus comprising a housing defining an inlet port (48), an outlet port (56), a vent port (58), and a flow path communicating each port with the others; a pair of relatively movable valve members movably received by said housing, a first (60) of said pair of valve members sealingly co-operating with said housing in a first position (64) to close fluid communication between said inlet port (48) and said outlet port (56), said first valve member (60) moving to a second position opening fluid communication between said inlet port (48) and said outlet port (56); the second (70) of said pair of valve members in a first position sealingly co-operating with said first valve member (60) to close fluid communication between said outlet port (56) and said vent port (58), said second valve member (70) moving to a second position opening communication between said outlet port (56) and said vent port (58); means (74) for moving either selected one of said pair of valve members respectively to said second position thereof; and means (78) for urging said selected one of said pair of valve members toward the respective first position thereof substantially as a first time derivative of fluid pressure at said outlet port (56).

Claim 6

Dependent Claim 61 words

Apparatus as claimed in Claim 3 wherein said urging means comprises a pressure-responsive member (78), pressure fluid absorptive volume (80) means communicating with said pressure-responsive member, passage means (68) communicating said outlet port (56) with said pressure fluid absorptive volume means (80), and flow restriction means (86) interposed between said outlet port (56) and said pressure fluid absorptive volume means (80).

Claim 7

Dependent Claim 77 words

Apparatus comprising a pressure responsive member (78), means (74) connecting said pressure responsive member to a valve member (70) movable to open and close fluid communication between a pair of port (56,48 or 58) and means( 68 ) communicating pressure fluid tosaid pressure responsive member to oppose movement of said valve member (70) in one of an opening and closing direction substantially as a first time derivative of fluid pressure at one of the pair of ports.

Claim 8

Dependent Claim 77 words

Apparatus comprising a pressure responsive member (78), means (74) connecting said pressure responsive member to a valve member (70) movable to open and close fluid communication between a pair of port (56,48 or 58) and means( 68 ) communicating pressure fluid tosaid pressure responsive member to oppose movement of said valve member (70) in one of an opening and closing direction substantially as a first time derivative of fluid pressure at one of the pair of ports.

Claim 9

Dependent Claim 99 words

A servo actuator system comprising a movable output member (16) the position of which is to be controlled in response to an input signal (98); motor means (102) for moving said output member in response to a flow of pressure fluid; valve means (46) controlling said flow of pressure fluid from a source (42) thereof to said motor means, and from said motor means to a low-pressure receiver (58) therefor, in response to said input signal; and negative feedback means (84,86) for opposing said input signal according to the second time derivative of position (acceleration) of said output member.

Claim 10

Dependent Claim 99 words

A servo actuator system comprising a movable output member (16) the position of which is to be controlled in response to an input signal (98); motor means (102) for moving said output member in response to a flow of pressure fluid; valve means (46) controlling said flow of pressure fluid from a source (42) thereof to said motor means, and from said motor means to a low-pressure receiver (58) therefor, in response to said input signal; and negative feedback means (84,86) for opposing said input signal according to the second time derivative of position (acceleration) of said output member.

Claim 11

Dependent Claim 103 words

Servo valve apparatus comprising an input member (74) selectively movable by input force to move a first (70) and a second (60) valve members respectively supplying and venting pressure fluid from a source (48) thereof to and from a receiver (58) therefor, each of said valve members defining a respective sealing area and being pressure responsive with respect to pressure fluid communicating with said receiver, means for counterbalancing pressure fluid forces effective upon said first and second valve members, and means for selectively increasingly inhibiting operation of said counterbalancing means in response to an increasing rate of fluid pressure change at said receiver.

Claim 12

Dependent Claim 103 words

Servo valve apparatus comprising an input member (74) selectively movable by input force to move a first (70) and a second (60) valve members respectively supplying and venting pressure fluid from a source (48) thereof to and from a receiver (58) therefor, each of said valve members defining a respective sealing area and being pressure responsive with respect to pressure fluid communicating with said receiver, means for counterbalancing pressure fluid forces effective upon said first and second valve members, and means for selectively increasingly inhibiting operation of said counterbalancing means in response to an increasing rate of fluid pressure change at said receiver.

Claim 13

Dependent Claim 77 words

A servo valve comprising a housing defining a fluid inlet (48), a fluid vent (58), and a fluid receiver passage (56), and including two valve members, one of which (60) controls communication between the inlet and the receiver passage at one valve seat (64) while the other (70) controls communication between the vent (58) and the receiver passage (56) at a second valve seat (72), the two members co-operating to define one of the valve seats (72).

Claim 14

Dependent Claim 77 words

A servo valve comprising a housing defining a fluid inlet (48), a fluid vent (58), and a fluid receiver passage (56), and including two valve members, one of which (60) controls communication between the inlet and the receiver passage at one valve seat (64) while the other (70) controls communication between the vent (58) and the receiver passage (56) at a second valve seat (72), the two members co-operating to define one of the valve seats (72).

Claim 15

Dependent Claim 46 words

9 . A valve as claimed in Claim 8 in which one of the valve members (70) can be driven in one sense or the other to open one valve seat (72) or to move the other member (60) to open the other valve seat (64).

Claim 16

Dependent Claim 43 words

A valve as claimed in Claim 8 or 9 including a feedback path (68) for fluid leading from the receiver passage (56) to a pressure chamber (80) for biassing the one valve member (70), the feedback path (68) preferably including a restriction (86).

Claim 17

Dependent Claim 55 words

A servo valve comprising a valve member (60 or 70) for controlling communication of fluid between a port (48 or 58) and a receiver (102), in which when the valve member is closed on its seat (64, 72) the fluid forces on the valve member are substantially balanced whereby the valve has high static gain.

Claim 18

Dependent Claim 55 words

A servo valve comprising a valve member (60 or 70) for controlling communication of fluid between a port (48 or 58) and a receiver (102), in which when the valve member is closed on its seat (64, 72) the fluid forces on the valve member are substantially balanced whereby the valve has high static gain.

Claim 19

Dependent Claim 32 words

A valve as claimed in Claim 11 in which as soon as the valve member starts to open the balance is upset in the sense to reduce the gain of the valve.

Claim 20

Dependent Claim 39 words

13 . A valve as claimed in either of the preceding claims in which when the valve member is open the dynamic gain of the valve decreases with increasing rate of an input signal for moving the valve member.

Claim 21

Independent Claim 203 words

The method of providing a servo valve apparatus having a variable ratio of fluid flow at an outlet port versus magnitude of control input applied thereto comprising the steps of: providing a first valve member movable to control fluid communication to said outlet port from an inlet port, which is substantially pressure balanced with respect to fluid pressure at the inlet port, and defining a respective sealing area between said inlet port and said outlet port; proving a second valve member movable to control fluid communication from said outlet port to a vent port, and further defining a respective sealing area substantially equal to said first sealing area; resiliently urging each of said first and second valve members to respective closed positions; providing input means for selectively moving either one of said first and second valve members to an open position in response to a respective control input; providing short term integrating memory means for receiving values of fluid pressure at said outlet port, integrating said values over time, and retaining the result of said integration as a memory value; and providing feed back means for biassing said input means in opposition to said control input as a function of said memory value.

Claim 22

Independent Claim 203 words

The method of providing a servo valve apparatus having a variable ratio of fluid flow at an outlet port versus magnitude of control input applied thereto comprising the steps of: providing a first valve member movable to control fluid communication to said outlet port from an inlet port, which is substantially pressure balanced with respect to fluid pressure at the inlet port, and defining a respective sealing area between said inlet port and said outlet port; proving a second valve member movable to control fluid communication from said outlet port to a vent port, and further defining a respective sealing area substantially equal to said first sealing area; resiliently urging each of said first and second valve members to respective closed positions; providing input means for selectively moving either one of said first and second valve members to an open position in response to a respective control input; providing short term integrating memory means for receiving values of fluid pressure at said outlet port, integrating said values over time, and retaining the result of said integration as a memory value; and providing feed back means for biassing said input means in opposition to said control input as a function of said memory value.

Claim 23

Dependent Claim 138 words

In a servo system for positioning an output member in response to a control signal, the method of providing varaible negative feedback of a time derivative of output member position as a function of said control signal, said method comprising the steps of: providing fluid pressure responsive motor means for moving and positioning said output member in response L o pressure fluid communicated thereto; providing servo valve means for selectively communicating pressure fluid from a source thereof to and from said motor means in response to said control signal; providing means for integrating over time the value of fluid pressure supplied by said servo valve to said motor means; and providing means to oppose said communication of pressure fluid to and from said motor means to oppose said control signal in response to the result of said integration.

Claim 24

Dependent Claim 138 words

In a servo system for positioning an output member in response to a control signal, the method of providing varaible negative feedback of a time derivative of output member position as a function of said control signal, said method comprising the steps of: providing fluid pressure responsive motor means for moving and positioning said output member in response L o pressure fluid communicated thereto; providing servo valve means for selectively communicating pressure fluid from a source thereof to and from said motor means in response to said control signal; providing means for integrating over time the value of fluid pressure supplied by said servo valve to said motor means; and providing means to oppose said communication of pressure fluid to and from said motor means to oppose said control signal in response to the result of said integration.

Claim 25

Independent Claim 65 words

A method of operating a servo system wherein an output member is movable by a fluid motor by applying an input signal to a control valve characterised by the application of negative feedback to the control valve resisting the input signal according to a function of fluid pressure downstream of the valve, and preferably analogous to a function of the acceleration of the output member.

Claim 26

Independent Claim 65 words

A method of operating a servo system wherein an output member is movable by a fluid motor by applying an input signal to a control valve characterised by the application of negative feedback to the control valve resisting the input signal according to a function of fluid pressure downstream of the valve, and preferably analogous to a function of the acceleration of the output member.

Servo apparatus

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag