DIFFERENTIAL LOCK WITH PRESSURE MODULATING EXHAUST VALVE

• US 3,640,360 A
• Filed: 10/17/1969
• Issued: 02/08/1972
• Est. Priority Date: 10/17/1969
• Status: Expired due to Term

• Current Assignee: William R. Dollase
• Original Assignee: William R. Dollase
• Inventors: Dollase, William R.
• Primary Examiner(s): Wyche, Benjamin W.
• Application Number:
  US04/867,281
• Time in Patent Office: 844 Days
• Field of Search: 192/85,19F 74/710.5 194/4A
• US Class Current: 192/220
• CPC Class Codes: B60K 23/04 for differential gearing
• CPC Class Codes: B60T 11/103 in combination with other control devices conjoint control of brake system and at least another sub-unit B60W10/188
• CPC Class Codes: B60T 13/18 with control of pump output delivery , e.g. by distributor valves B60T13/167 takes precedence
• CPC Class Codes: B62D 11/10 using gearings with differential power outputs on opposite sides, e.g. twin-differential or epicyclic gears
• CPC Class Codes: F16H 2048/204 Control of arrangements for suppressing differential actions
• CPC Class Codes: F16H 2048/305 using manual actuators
• CPC Class Codes: F16H 2200/2071 using three freewheel mechanism
• CPC Class Codes: F16H 48/08 comprising bevel gears
• CPC Class Codes: F16H 48/22 using friction clutches or brakes
• CPC Class Codes: F16H 48/30 using externally-actuatable means
• CPC Class Codes: F16H 48/32 using fluid pressure actuators
• CPC Class Codes: F16H 48/34 using electromagnetic or electric actuators
• CPC Class Codes: Y10T 137/8663 Fluid motor
• CPC Class Codes: Y10T 137/87233 Biased exhaust valve

Abstract

A control system for a differential having first and second output shafts and hydraulic brakes for the respective shafts. The control system includes a friction device for locking and unlocking the differential and a valve which progressively pressurizes the friction device in timed relation to initial supply of pressured fluid from a source to the valve. The valve cooperates with the brakes and releases the friction device whenever either of the brakes is actuated.

Claims

1. In a vehicle having a power train including a driven differential having first and second output shafts;

a fluidoperated friction device for selectively locking and unlocking said differential; and

a fluid system including a pressured fluid sourcE, a reservoir, a control valve and conduit means connecting said source, reservoir and friction device to said control valve, the improvement of said control valve comprising;

a housing having a first flow path connecting said source to said friction device; and

means progressively increasing the pressure of fluid in said first flow path, said last means including a plurality of separate secondary flow paths between said first flow path and said reservoir;

a control flow path leading from the main flow path; and

movable means responsive to the pressure of fluid in the control flow path to block an increased number of the secondary flow paths in timed relation to initial pressurization of said main flow path.

2. The combination as defined in claim 1, in which said last means includes means defining a chamber having one end in communication with said first flow path, an intermediate portion communicating with said reservoir, and an opposite end communicating with said control flow path;

and a piston slidable in said chamber and normally maintained in a first position, said piston cooperating with said chamber to define said secondary flow paths.

3. The combination as defined in claim 2, further including orifice means in said control flow path restricting flow to said chamber.

4. The combination as defined in claim 2, in which said piston has a plurality of openings defining said secondary flow paths.

5. A fluid control system as defined in claim 3, in which said first flow path has second orifice means therein and said control flow path communicates with said main flow path downstream of the second orifice means;

and said piston has first and second opposed cross-sectional areas respectively exposed to the fluid in said secondary flow paths and said control flow path, said second area being greater than said first area whereby said piston will be moved from a first position with substantially equal pressure of fluid on opposite ends of said piston.

6. The combination as defined in claim 1, and including first and second fluid pressure operated brakes and control means selectively supplying pressured fluid from said source to said brakes, the further improvement of a valve spool slidable in a bore in said housing, said spool having a detented operative position accommodating flow of fluid from said source through said first flow path and means operatively connecting said control means to said bore to move said valve spool from the operative position when either of said brakes are engaged and block the flow of fluid from said source to said friction device when said brakes are engaged.

7. In a vehicle having a power train including a driven differential having first and second output shafts;

a fluid-operated friction device for selectively locking and unlocking said differential; and

a fluid system including a pressured fluid source, a reservoir and a control valve, and conduit means connecting said source, reservoir and friction device to said control valve, the improvement of said control valve comprising;

a housing having a first flow path connecting said source to said friction device;

branch path means connecting said first flow path to said reservoir;

means defining a chamber having one end in communication with said branch path and an intermediate portion communicating with said reservoir;

a piston slidable in said chamber, said piston having a plurality of openings providing communication of said branch path with said reservoir;

biasing means normally maintaining said piston in a first position accommodating substantially unrestricted flow from first flow path to said reservoir through said openings to prevent an increase in pressure of the fluid to said friction device;

means defining a control flow path between said first flow path and an opposite end of said chamber; and

orifice means in said control flow path restricting flow to said chamber, the flow of fluid to said chamber moving said piston from said position to block an increased number of opEnings and progressively restrict the flow of fluid through said branch path to thereby increase the pressure of fluid to said friction device and cause gradual engagement of said friction device.

8. A vehicle as defined in claim 7, and including first and second fluid pressure operated brakes and control means selectively supplying pressured fluid from said source to said brakes, the further improvement of a valve spool slidable in a bore in said housing, said spool having a detented operative position accommodating flow of fluid from said source through said first flow path and means operatively connecting said control means to said bore to move said valve spool from the operative position when either of said brakes are engaged and block the flow of fluid from said source to said friction device when said brakes are engaged.

9. The combination as defined in claim 7, including the further improvement of orifice means in said first flow path restricting flow of fluid from said source to said device and said control flow path.

10. In a vehicle having a power train including a driven differential having first and second output shafts;

a fluid-operated friction device for selectively locking and unlocking said differential; and

a fluid system including a pressured fluid source, a reservoir, a control valve; and

conduit means connecting said source, reservoir and friction device to said control valve, the improvement of said control valve comprising;

a housing having a first flow path connecting said source to said friction device with a valve bore intersecting said first flow path;

a valve spool slidable in said bore and having a first inoperative position blocking flow in said path and an operative position accommodating flow in said path;

branch path means connecting said first flow path to said reservoir downstream of said valve bore;

means defining a chamber intersecting said branch path with a piston slidable in said chamber;

biasing means normally maintaining said piston in a first position accommodating substantially unrestricted flow of fluid through said branch path;

means defining a control flow path communicating at one end with said first flow path between said valve bore and said branch path and at its opposite end with one end of said chamber and said piston so that movement of said valve spool to the operative position will progressively increase the pressure of fluid in said one end of said chamber and move said piston, said piston having orifice means therethrough to progressively restrict the flow of fluid through said branch path when said valve spool is moved to said operative position and thereby progressively increase the pressure of fluid to said friction device to cause gradual engagement of said friction device.