Electro/pneumatic proportional valve

• US 4,638,837 A
• Filed: 11/13/1984
• Issued: 01/27/1987
• Est. Priority Date: 11/13/1984
• Status: Expired due to Fees

• Current Assignee: Allied Corp. (Honeywell International Inc.)
• Original Assignee: Allied Corp. (Honeywell International Inc.)
• Inventors: Buike, James W., Eddy, William C.
• Primary Examiner(s): Rosenthal, Arnold
• Application Number:
  US06/670,686
• Time in Patent Office: 805 Days
• Field of Search: 137/627.5, 137/625.64, 137/596.18, 137/596.14, 137/596.16, 251/129.05, 251/30, 91/457, 91/433
• US Class Current: 137/627.5
• CPC Class Codes: B62D 5/06 fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
• CPC Class Codes: B62D 5/10 characterised by type of power unit
• CPC Class Codes: F16K 31/124 servo actuated
• CPC Class Codes: Y10T 137/86614 Electric
• CPC Class Codes: Y10T 137/86919 Sequentially closing and opening alternately seating flow controllers
• CPC Class Codes: Y10T 137/87209 Electric
• CPC Class Codes: Y10T 137/87225 Fluid motor

Abstract

An electro/pneumatic proportional valve having a housing defining an upper and lower chamber separated by an annular web. An inlet port and exhaust port concentric with the annular web are provided in said lower chamber while an outlet port is provided in the upper chamber. An exhaust cylinder is resiliently disposed through the exhaust port and has a radial flange engaging said annular web to occlude the annular web'"'"'s central opening. The exhaust cylinder also has an axial bore passing therethrough and exiting through the exhaust port. A piston disposed in the upper chamber has a pintle which is operative to engage the exhaust cylinder with the displacement of the piston and occlude the exhaust cylinder'"'"'s axial bore. Pilot valves are provided to pressurize the upper chamber in response to a pulse train signal displacing the piston towards the web. The displacement of the piston causes the pintle to engage the exhaust cylinder and unseat it from the annular web.

Claims

1. An electrically actuated proportional valve for outputting a fluid at a pressure proportional to at least one continuously variable component of an electrical signal comprising:

an enclosed housing defining an internal chamber, said housing having an inlet port for receiving a pressurized fluid, an outlet port, and vent port;

a piston disposed in said internal chamber operative to assume a first position and displaceable in response to a fluid pressure applied to one side of said piston;

first valve means, opened in response to said piston being in said first position to connect said outlet port to said vent port and closed in response to said piston being displaced from said first position;

second valve means closed in response to said piston being in said first position and opened in response to said piston being displaced from said first position to connect said outlet port with said inlet port, said second valve in said open state also applying a fluid pressure to the side of said piston opposite said one side to balance the position of said piston such that the fluid pressure at the outlet port is proportional to the fluid pressure applied to said one side of the piston; and

electrically actuated pilot valve means responsive to the electrical signal for applying a fluid to said one side of said piston having a fluid pressure proportional to the value of the variable component of said electrical signal, said fluid pressure displacing said piston and opening said second valve means to produce a pressure applied to the other side of said piston and at said outlet port proportional to the value of the variable component of said electrical signal.

5. The proportional valve of claim 1 wherein the electrical signal is a pulse train signal comprising sequentially generated pulses at a predetermined frequency, and wherein the duration of each pulse is indicative of the desired pressure at the outlet port, said pilot valve means comprises:

a first solenoid valve responsive to said pulse train signal for supplying a quantity of air proportional to the duration of the pulses in said pulse train signal to said upper chamber on said one side of the piston; and

a second solenoid valve responsive to said pulse train signal for venting to the atmosphere a quantity of air from said upper chamber on said one side of the piston, said first and second solenoid valves operating in a complementary manner such that when said first solenoid valve is supplying air to said upper chamber said second solenoid valve is closed and when said first solenoid valve is closed, said second solenoid valve is open venting said upper chamber on said one side of the piston.

6. The proportional valve of claim 5 wherein said first solenoid valve is a normally closed valve and said second solenoid valve is a normally open valve.

7. The proportional valve of claim 5 wherein said first and second solenoid valves are normally closed valves, said second solenoid valve is actuated by the logical compliment of said pulse train signal.

2. An electrically actuated proportional valve for outputting a fluid at a pressure proportional to at least one continuously variable component of an electrical signal comprising:

an enclosed housing defining an internal chamber, said housing having an inlet port for receiving a pressurized fluid, an outlet port, and vent port;

a piston disposed in said internal chamber operative to assume a first position and displaceable in response to a fluid pressure applied to one side of said piston;

first valve means, opened in response to said piston being in said first position to connect said outlet port to said vent port and closed in response to said piston being displaced from said first position;

second valve means closed in response to said piston being in said first position and opened in response to said piston being displaced from said first position to connect said outlet port with said inlet port, said second valve in said open state also applying a fluid pressure to the side of said piston opposite said one side to balance the position of said piston such that the fluid pressure at the outlet port is proportional to the fluid pressure applied to said one side of the piston;

electrically actuated pilot valve means responsive to the electrical signal for applying a fluid to said one side of said piston having a fluid pressure proportional to the valve of the variable component of said electrical signal, said fluid pressure displacing said piston and opening said second valve means to produce a pressure applied to the other side of said piston and at said outlet port proportional to the value of the variable component of said electrical signal;

wherein said housing has an intermediate annular web dividing said chamber into an upper chamber and a lower chamber, and wherein said inlet port and exhaust port are provided in said lower chamber, said outlet port is provided in said upper chamber and said piston is disposed in said upper chamber.

3. The proportional valve of claim 2 wherein said annular web has a central aperture and said exhaust port is concentric with said central aperature, said first and second valve means comprises:

an exhaust cylinder, slidably disposed through said exhaust port, said exhaust cylinder having a radial flange adjacent to said intermediate web and an axial bore provided therethrough and exiting through said exhaust port said radial flange having a diameter larger than said central aperture;

first resilient means for biasing said exhaust cylinder towards siad annular web causing said radial flange to occlude said central aperture,

a pintle connected to said piston concentric with said exhaust cylinder, said pintle having a diameter greater than the diameter of said axial bore and operative to occlude said axial bore and displace said radial flange away from said annular web when said piston is displaced from said first position.

4. The proportional valve of claim 3 wherein said pintle has a webbed guide finger slidably received in said exhaust port to maintain alignment of the pintle with the exhaust cylinder'"'"'s axial bore.

8. An electro/pneumatic proportional valve for outputting air received from an external source at a pressure proportional to the duration of the pulses of a pulse train signal, comprising:

an enclosed housing defining an internal chamber having an inlet port for receiving pressurized air from the external source, an outlet port, and an exhaust port vented to the atmosphere;

a piston disposed in said chamber, said piston having a first position and displaceable in response to an air pressure being applied to the top side of said piston;

first valve means open in response to said piston being in said first position to connect said outlet port with said exhaust port and closed in response to said piston being displaced from said first position;

second valve means closed in response to said piston being in said first position and opened in response to said piston being displaced from said first position to connect said outlet port with said inlet port, said second valve in said open state also supplying air from said inlet port to the bottom side of said piston to balance the position of said piston such that the pressure at the outlet port is proportional to the pressure applied to the top side of said piston; and

electrically actuated pilot valve means responsive to said pulse train signal for supplying air to the top side of the piston at a pressure proportional to the duration of the individual pulses in the pulse train signal, said air displacing said piston and opening said second valve to produce a pressure at applied to the other side of said piston and said outlet port proportional to the duration of the individual pulses of the pulse train signal.

9. The proportional valve of claim 8 wherein said housing an intermediate annular web dividing said chamber into an upper chamber and a lower chamber, and wherein said inlet port and exhaust port are provided in said lower chamber, said outlet port is provided in said upper chamber and said piston is disposed in said upper chamber.

10. The proportional valve of claim 9 wherein said annular web has a central aperture and said exhaust port is concentric with said central aperature, said first and second valve means comprises:

an exhaust cylinder, slidably disposed through said exhaust port, said exhaust cylinder having a radial flange adjacent to said intermediate web and an axial bore provided therethrough and exiting through said exhaust aperture said radial flange having a diameter larger than said central aperture;

first resilient means for biasing said radial flange against said intermediate web to occlude said central aperture;

a pintle connected to said piston concentric with said exhaust cylinder, said pintle having a diameter greater than the diameter of said axial bore and operative to occlude said axial bore and displace said exhaust cylinder from said annular web when said piston is displaced from said first position.

11. The proportional valve of claim 10 wherein said pintle has a webbed guide finger slidably received in said exhaust port to maintain alignment of the pintle with the exhaust cylinder'"'"'s axial bore.

12. The proportional valve of claim 8 wherein said pilot valve means comprises:

a first solenoid valve responsive to said pulse train signal for supplying a quantity of air to said upper chamber on said top side of the piston; and

a second solenoid valve responsive to said pulse train signal for exhausting to the atmosphere a quantity of air from said upper chamber on said top side of the piston, said first and second solenoid valves operating in a complemetary manner such that when said first solenoid valve is supplying air to said upper chamber said second solenoid vale is closed and when said first solenoid valve is closed, said second solenoid valve is open exhausting said upper chamber on the top side of said piston to the atmosphere.

13. The proportional valve of claim 12 wherein said first solenoid valve is a normally open valve and said second solenoid valve is a normally closed valve.

14. The proportional valve of claim 12 wherein said first and second solenoid valves are normally closed valves, said second solenoid valve is actuated by the logical complement of said pulse train signal.

15. The proportional valve of claim 10 having second resilient means for biasing said piston to said first position.

16. An electro/pheumatic valve for providing an output air flow having a pressure proportional to a variable component of a received pulse train signal comprising;

an enclosed housing defining an internal chamber, said housing having an internal annular web dividing said internal chamber into an upper chamber and a lower chamber, said annular web having a central opening;

an inlet port provided through said housing into said lower chamber;

an outlet port provided through said housing into said upper chamber;

an exhaust port provided through said housing into said lower chamber concentric with said central opening;

a piston disposed in said upper chamber above said outlet port, said piston operative to assume a first position and displaceable from said first position towards said annular web;

a cylindrical exhaust cylinder slidably disposed through said exhaust port, said exhaust cylinder having a radial flange adjacent to said web and axial fluid passageway therethrough, said radial flange having a diameter sufficient to occlude said central opening;

means for resiliently biasing said exhaust cylinder towards said web;

a pintle attached to said piston concentric with said axial fluid passageway, said pintle having a diameter smaller than said central opening but sufficiently large to occlude said fluid passageway;

electrically actuated pilot valve means for supplying air to said upper chamber above said piston in response to said pulse train signal, said air supplied to said upper chamber having a pressure proportional to the variable component of the received pulse train signal and operative to displace said piston and pintle towards said web, the displacement of said pintle occluding the axial fluid passageway and displacing said radial flange from said annular web to provide an air flow at the outlet port having a pressure proportional to the variable component of the received pulse train signal.

17. The proportional valve of claim 16 wherein said pilot valve means comprises;

a first solenoid valve for supplying a quantity of air to said upper chamber above said piston in response to each pulse in said pulse wave train, said quantity of air proportional to the pulse duration of each pulse in the pulse train signal; and

a second solenoid valve for exhausting the air from said upper chamber above said piston in response to said pulse train signal, said first and second valves operating in a complementary manner such that when one is opened the other is closed and vice versa.

18. The proportional valve of claim 17 wherein said first solenoid valve is a normally closed valve and said second solenoid valve is a normally open valve.

19. The proportional valve of claim 16 having means for biasing said piston to said first position.