CN-114076057-B - Valve assembly having an electric actuator with balanced stator

Abstract

A valve assembly for a pump includes an electric actuator having a stator and an armature. The stator includes an annular outer stator portion and an annular inner stator portion, and an annular channel formed radially between the outer stator portion and the inner stator portion. The first radial passage extending through the annular outer stator portion and the at least one second opening in the annular outer stator portion between the outer surface of the outer stator portion and the annular passage results in magnetic symmetry of the stator. Upon actuation of the electric actuator, the attraction of the armature toward the stator is uniform, thus diverting fluid between the stator and the armature in a uniform manner and avoiding high-speed, potentially damaging fluid flow.

Inventors

• B.E. Nelson
• N - M - Aria
• A.J. MANSON

Assignees

• 卡特彼勒公司

Dates

Publication Date

20260505

Application Date

20210812

Priority Date

20200813

Claims (20)

1. 1.A valve assembly, comprising: A valve member operatively associated with a valve seat, the valve member being movable along a central axis between a first open position in which the valve member is spaced apart from the valve seat and a second closed position in which the valve member engages the valve seat to seal an opening of the valve assembly; an electric actuator including a stator and an armature coupled to the valve member; The stator includes an annular outer stator portion and an annular inner stator portion, and an annular channel formed radially between the outer stator portion and the inner stator portion, a first radial channel extending through the annular outer stator portion between an outer surface of the outer stator portion and the annular channel, and at least one second opening disposed within the annular outer stator portion on a half of the stator opposite the first radial channel; a winding and terminal assembly including a conductive winding disposed within the annular channel and between the outer stator portion and the inner stator portion and a conductive terminal electrically connected to the winding, a portion of the winding and terminal assembly extending through the first radial channel, and The armature includes an armature plate defining an armature central axis that is collinear with the central axis and movable between a rest position and an actuated position to change a position of the valve member in response to a change in an energy state of the electric actuator, the armature plate including a top armature surface facing the stator.
2. 2. The valve assembly of claim 1, wherein the at least one second opening includes a second radial passage extending through the annular outer stator portion between an outer surface of the outer stator portion and the annular passage, the second radial passage being radially opposite the first radial passage.
3. 3. The valve assembly of claim 1, further comprising an insulating overmold surrounding the windings and disposed in the annular channel.
4. 4. The valve assembly of claim 1, wherein the outer stator portion comprises an outer stator end face and the inner stator portion comprises an inner stator end face, and the outer stator end face and the inner stator end face lie in a common plane.
5. 5. The valve assembly of claim 1, wherein the winding and terminal assembly further comprises a spool assembly on which the winding is wound.
6. 6. The valve assembly of claim 1, wherein the at least one second opening includes a second radial passage extending through the annular outer stator portion between an outer surface of the outer stator portion and the annular passage, the second radial passage aligned with the first radial passage and located on an opposite side of the central axis.
7. 7. The valve assembly of claim 1, wherein the stator has an upper surface and a lower surface, the lower surface being disposed closer to the armature plate than the upper surface, and the lower surface of the stator is radially symmetrical.
8. 8. The valve assembly of claim 1, wherein the stator has an upper surface and a lower surface, the lower surface being disposed closer to the armature plate than the upper surface, the lower surface being symmetrical about a bisector passing through the first radial passage and intersecting the central axis and being perpendicular to the central axis.
9. 9. The valve assembly of claim 8, wherein an outer surface of the outer stator portion is symmetrical about the bisector.
10. 10. The valve assembly of claim 8, wherein the stator is symmetrical about the bisector.
11. 11. The valve assembly of claim 1, further comprising an overmolded body extending around the stator and into each of the first radial channel and the at least one second opening.
12. 12. A valve assembly, comprising: A valve member operatively associated with a valve seat, the valve member being movable along a central axis between a first open position in which the valve member is spaced apart from the valve seat and a second closed position in which the valve member engages the valve seat to seal an opening of the valve assembly; an electric actuator including a stator and an armature coupled to the valve member; The stator includes an annular outer stator portion and an annular inner stator portion, and an annular channel formed radially between the outer stator portion and the inner stator portion, a first radial channel extending through the annular outer stator portion between an outer surface of the outer stator portion and the annular channel, and at least one second opening disposed within the annular outer stator portion on a half of the stator opposite the first radial channel; A winding and terminal assembly including a conductive winding disposed inside the annular channel and between the outer stator portion and the inner stator portion and a conductive terminal electrically connected to the winding, a portion of the winding and terminal assembly extending through the first radial channel; An overmolded body extending around the stator and into each of the first radial channel and the at least one second opening, and The armature includes an armature plate defining an armature central axis that is collinear with the central axis and movable between a rest position and an actuated position to change a position of the valve member in response to a change in an energy state of the electric actuator, the armature plate including a top armature surface facing the stator.
13. 13. The valve assembly of claim 12, further comprising an insulating overmold surrounding the windings and disposed in the annular channel.
14. 14. The valve assembly of claim 12, wherein the stator has an upper surface and a lower surface, the lower surface being disposed closer to the armature plate than the upper surface, and the lower surface of the stator is radially symmetrical.
15. 15. The valve assembly of claim 12, wherein the stator has an upper surface and a lower surface, the lower surface being disposed closer to the armature plate than the upper surface, the lower surface being symmetrical about a bisector passing through the first and second radial passages and intersecting the central axis.
16. 16. The valve assembly of claim 15, wherein an outer surface of the outer stator portion is symmetrical about the bisector.
17. 17. The valve assembly of claim 15, wherein the stator is symmetrical about the bisector.
18. 18. The valve assembly of claim 15, wherein the overmold extends around the stator and into each of the first and second radial channels.
19. 19. A pump, comprising: A pump housing; A pumping element movable within a pumping chamber formed in the pump housing between a retracted position and an advanced position; a valve assembly for controlling fluid flow into or out of the pumping chamber, the valve assembly comprising A valve member operatively associated with a valve seat, the valve member being movable along a central axis between a first open position in which the valve member is spaced apart from the valve seat and a second closed position in which the valve member engages the valve seat to seal an opening of the valve assembly; an electric actuator including a stator and an armature coupled to the valve member; The stator includes an annular outer stator portion and an annular inner stator portion, and an annular channel formed radially between the outer stator portion and the inner stator portion, a first radial channel extending through the annular outer stator portion between an outer surface of the outer stator portion and the annular channel, and at least one second opening disposed within the annular outer stator portion on a half of the stator opposite the first radial channel; A winding and terminal assembly including a conductive winding disposed within the annular channel between the outer stator portion and the inner stator portion and a conductive terminal electrically connected to the winding, a portion of the winding and terminal assembly extending through the first radial channel; The armature includes an armature plate defining an armature central axis that is collinear with the central axis and movable between a rest position and an actuated position to change a position of the valve member in response to a change in an energy state of the electric actuator, the armature plate including a top armature surface facing the stator.
20. 20. The pump of claim 19, further comprising an overmolded body extending around the stator and into each of the first radial channel and the at least one second opening.

Description

Valve assembly having an electric actuator with balanced stator Technical Field The present disclosure relates generally to stator design and operation in an electric actuator, and more particularly to a valve assembly having an electric actuator stator shaped to limit high-speed flow of fluid displaced by movement of an armature in the valve assembly. Background Many different pump designs are used to deliver and pressurize fluids. In the context of fuel systems, for example, for internal combustion engines, electronically controlled high pressure fuel pumps are common and pressurize fuel (e.g., diesel fuel) for injection into engine cylinders. High pressure fuel injection strategies have been shown to be effective in reducing emissions operation. In one design, a high pressure fuel pump supplies a so-called common rail that provides a fluid reservoir that stores a quantity of pressurized fuel for delivery to a plurality of fuel injectors. In other designs, the fuel pump is separately associated with the fuel injector, referred to as a unit pump. To achieve a high level of control over moving parts within such pumps, electrical actuators, such as solenoid actuators, are used to control valve positioning and fluid connection. When an electrical current is applied, the solenoid produces a magnetic field that can generate a localized force with sufficient energy to actuate components within the fuel system hardware. Engineers have been testing a variety of different electric actuator and pump designs for many years. With increasing pressure and control of fuel injection quantity, fuel injection rate, and other characteristics, electrical actuators and associated valve components within a fuel pump tend to move relatively rapidly and may impact a valve seat, stopper, or other surface with relatively high force. An exemplary fuel pump design is known from U.S. patent No.5,743,23 to Shorey et al. In the configuration shown by Shorey et al, an electric actuator is used to control a valve that changes position significantly to alternately allow or prevent fuel flow to the pumping chamber. Disclosure of Invention In one aspect, a valve assembly includes a valve member operably associated with a valve seat, wherein the valve member is movable along a valve central axis between a first open position in which the valve member is spaced apart from the valve seat and a second closed position in which the valve member engages the valve seat to seal an opening of the valve assembly. The electric actuator includes a stator and an armature coupled to the valve member. The stator includes an annular outer stator portion and an annular inner stator portion, and an annular channel formed radially between the outer stator portion and the inner stator portion. A first radial passage extends through the annular outer stator portion between an outer surface of the outer stator portion and the annular passage. At least one second opening is provided in the annular outer stator part on the opposite half of the stator to the first radial passage. The stator is magnetically symmetric along a line bisecting the first radial passage and perpendicular to the central axis. The winding and terminal assembly includes an electrically conductive winding disposed within the annular channel and between the outer stator portion and the inner stator portion and an electrically conductive terminal electrically connected to the winding. A portion of the winding and terminal assembly extends through the first radial passage. The armature includes an armature plate defining an armature central axis, wherein the armature central axis is collinear with the valve central axis and movable between a rest position and an actuated position to change a position of the valve member in response to a change in an energy state of the electric actuator. The armature plate includes a top armature surface facing the stator. In another aspect, a valve assembly includes a valve member operably associated with a valve seat, wherein the valve member is movable along a valve central axis between a first open position in which the valve member is spaced apart from the valve seat and a second closed position in which the valve member engages the valve seat to seal an opening of the valve assembly. The electric actuator includes a stator and an armature coupled to the valve member. The stator includes an annular outer stator portion and an annular inner stator portion, and an annular channel formed radially between the outer stator portion and the inner stator portion. A first radial passage extends through the annular outer stator portion between an outer surface of the outer stator portion and the annular passage. At least one second opening is provided in the annular outer stator part on the opposite half of the stator to the first radial passage. The stator is magnetically symmetric along a line bisecting the first radial passage and perpendicular to the central axis.