Electromechanical valve and method of assembly

Abstract

In at least some embodiments, a method of assembling an electromechanical valve includes positioning an armature stop in a first position, the first position being at a first distance from a valve seat; actuating the valve to move the armature away from the valve seat; providing a fluid flow to the valve; determining fluid flow characteristics; and moving the armature stop relative to the valve seat to a second position according to the fluid flow characteristic, the second position being at a distance different from the first distance.

Description

[0001] Reference to relevant applications This application claims the benefit of U.S. Provisional Application Serial No. 62 / 760,099, filed November 13, 2018, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to an electromechanical valve including a coil that generates a magnetic field to drive an armature when energized, and the invention also relates to a method of assembling such a valve. Background Technology

[0003] Valves, such as solenoid valves, may include valve elements or heads that move relative to a valve seat when energy is supplied to the valve to selectively allow fluid to flow through the valve seat and / or out of the valve's outlet. Due to tolerances in the manufacture and assembly of the various components of the valve, the flow rate and / or pressure of the fluid flowing from the valve outlet may vary from one valve to the next during the production operation of such valves. Summary of the Invention

[0004] In at least some embodiments, a method of assembling an electromechanical valve includes: positioning an armature stop in a first position at a first distance from a valve seat; actuating the valve to move the armature away from the valve seat; supplying fluid flow to the valve; determining fluid flow characteristics; and, based on the fluid flow characteristics, moving the armature stop relative to the valve seat to a second position at a distance different from the first distance.

[0005] In at least some embodiments, the step of moving the armature stop is accomplished by moving the armature stop without moving another component of the valve. In at least some embodiments, the step of moving the armature stop is accomplished by moving the component to which the armature stop is connected. In at least some embodiments, the step of moving the armature stop is performed while fluid is flowing through the valve. In at least some embodiments, the step of moving the armature stop is performed when fluid is not flowing through the valve, and the method further includes the step of determining the fluid flow characteristics after the armature stop has been moved.

[0006] In at least some embodiments, the fluid flow characteristics are one or more of the following: fluid flow rate through one or more outlets of the valve, fluid flow rate through one or more inlets of the valve, fluid pressure at one or more inlets, and fluid pressure at one or more outlets.

[0007] In at least some embodiments, the armature stop is press-fitted to a portion of the housing, and the step of moving the armature stop is accomplished by moving the armature stop relative to that portion of the housing, or by moving that portion of the housing to which the armature stop is press-fitted. The valve may include a housing and a cover, and the armature stop may be press-fitted to the cover, wherein the cover is coupled to the housing to close an open end of the housing. The valve may include a winding tube having a channel, the winding tube being received within the housing, an armature being received within the channel, and a portion of the armature stop being received within the channel, and the step of moving the armature stop is accomplished by moving the armature stop within the channel and relative to the winding tube.

[0008] In at least some embodiments, a method of assembling an electromechanical valve includes: positioning an armature stop in a first position at a first distance from a valve seat; actuating the valve to move the armature away from the valve seat; supplying fluid flow to the valve; determining fluid flow characteristics; and moving the armature stop relative to the valve seat if the fluid flow characteristics are outside a predetermined threshold value.

[0009] In at least some embodiments, a housing and a cover are provided, an armature is received in the housing, and the method includes fitting an armature stop to the cover and fitting the cover to the housing to position the armature stop in a first position. The step of moving the armature stop can be accomplished by moving the cover relative to the housing, or moving the armature stop relative to the cover, or both. The armature stop can be coupled to the cover by an interference fit, and the step of fitting the armature stop to the cover can be accomplished by pressing the armature stop into an opening in the cover. The step of moving the armature stop can be accomplished by linearly moving the armature stop or rotating the armature stop. In at least some embodiments, the armature stop in the first position is further away from the valve seat than after the step of moving the armature stop. Attached Figure Description

[0010] Specific embodiments and preferred modes will now be described in detail with reference to the accompanying drawings, in which: Figure 1 It is a perspective view of an electromechanical valve (such as a solenoid valve), showing the cover and the armature stop carried by the cover, which is in the first position and removed from the valve; Figure 2 This is a perspective view showing the armature stop removed from the cover; Figure 3 yes Figure 1 A cross-sectional view of the valve, showing its position relative to... Figure 1 Armature stop and cover at the same location; Figure 4 This is a cross-sectional view of the valve, showing the armature stop and cover assembled to the armature in the first assembly position; and Figure 5 This is a cross-sectional view of the valve in its final assembly position. Detailed Implementation

[0011] Please refer to the attached diagram for more details. Figure 1 An electromechanical valve 10 with a valve element is shown, which is actuated between a first position and a second position to change the flow rate of fluid through the valve. Figure 3-5 As shown, valve 10 can be a so-called solenoid valve with a coil 12 that generates a magnetic field when energized to drive an armature 14, which includes a valve element or moves the valve element between a first position and a second position. The first position can be a closed position, in which the fluid flow through valve 10 (e.g., from the valve outlet) is at a minimum velocity, which may include no flow. The second position can be an open position, in which the fluid flow rate is greater than the flow rate when the valve element is in the first position, and the second position may include a fully open position, in which the flow rate is at its maximum value.

[0012] Reference Figure 1-3 The solenoid valve 10 includes a winding tube 20 having a body 22. The body 22 includes an internal channel 24 having an axis and spaced-apart, radially outwardly extending flanges 26, 28. The channel 24 is accessible to a first end 30 of the body 22 and extends toward or through an axially opposite second end 32 of the body. The channel 24 may be cylindrical and may have a constant diameter, or the channel may be of a different shape and have a diameter or size that varies along its axial length as needed. A coil 12 is wound around the body 22 of the winding tube, thereby surrounding the channel 24, and the ends 34, 36 of the coil 12 ( Figure 1 They are arranged such that they can be coupled to terminals or other electrical contacts 38, which are adapted to be coupled to a connector, which in turn is coupled to a power source.

[0013] To receive or support electrical terminals (connected to coil 12 and through which power is supplied to valve 10), the winding tube body 22 may include terminal cavities or terminal supports 40 that receive or extend along electrical terminals or contacts 38, such as spade connectors or different connector configurations. In the illustrated example, three upright supports 40 define two opening regions 42 between them, which may be partially defined by recesses formed in the uprights 40, in which protrusions from the electrical connector may be slidably received. Conductive contacts 38 may be disposed in at least a portion of the opening regions 42 such that the contacts 38 are engaged by corresponding terminals during assembly, which are also connected to a power source. The ends 34, 36 of coil 12 are electrically connected in any suitable manner to the contacts 38 or terminals carried by the winding tube body 22. In the example shown, the ends 34, 36 of the coil 12 are also physically connected to each contact 38, and excess wire length may be wound around the two extending from or adjacent to the individual posts 46 of the support 40. Of course, the terminal or electrical connector arrangement of the solenoid valve 10 can be arranged in any suitable manner, and the example shown is merely one possibility. The body 22 and the electrical connector arrangement (e.g., the support 40) can be integrated into the same component and can be formed in the same piece of material, for example, by a molding process.

[0014] like Figure 3-5 As shown, the winding tube 20, including the coil 12, can be received within a cavity 48 of the housing 50. The housing 50 may have a sidewall 52, which may be generally cylindrical, open at one end 54, and at its other end at least partially closed by a base 56 extending inwardly from the sidewall 52. The base 56 may include an opening 58 aligned with a channel 24 in the winding tube body 22. A fluid passage 60, including a valve seat 62 or at least partially defined by the valve seat 62, may be formed in the housing 50. The valve seat 62 may be aligned with the opening 58 and the channel 24, and may be defined by an integral portion of the housing 50 surrounding a portion of the fluid passage 60.

[0015] The fluid passage 60 may extend into and be at least partially defined by a cylindrical boss 64 or a reduced-diameter portion extending from the base 56. The valve seat 62, at least one inlet 66, and at least one outlet 68 of the fluid passage 60 may be defined in the boss 64 or elsewhere by the housing 50 or by different components adjacent to the solenoid valve 10. In at least some embodiments, the inlet 66 is defined by an open end of the boss 64 and may be axially aligned with the opening 58, the passage 60, and the valve seat 62. The inlet 66 defines a portion of the fluid passage 60 located upstream of the valve seat 62, through which fluid enters the housing 50. Downstream of the valve seat 62, one or more fluid outlets 68 may be provided in the housing 50, through which fluid exits the housing 50. Of course, fluid can flow through the valve in the opposite manner, i.e., into passage 60 via port(s) 68 and out of passage 60 via port(s) 66 (i.e., what is referred to herein as an outlet may also be an inlet, and vice versa). The boss 64 may be generally cylindrical and arranged to be fitted into a fluid passage or complementary-shaped chamber of the component in which the flow of fluid needs to be controlled. It may be axially oriented toward the coil 20 and its passage 24, and at least a portion of the valve seat 62 may be radially smaller than the coil passage 24 (e.g., extending inward relative to the internal passage and / or providing a shoulder in or adjacent to the internal passage). The housing 50 may be formed of metal and may define a portion of the flux path of the solenoid valve 10, as will be described. The housing may be formed with any desired number of components and / or constructions.

[0016] To control the fluid flow through the valve seat 62, the armature 14 is slidably received in the winding channel 24 and / or the fluid channel 60, and the valve seat 62 can be opened and closed, or its opening and closing can be controlled, when the armature 14 is driven by the solenoid. The armature 14, or at least a portion thereof, may be ferromagnetic and is driven from a first position to a second position when the coil 12 is powered. In at least some embodiments, when the armature 14 is in the first position, the fluid flow through the valve seat 62 is suppressed or prevented, and when the armature 14 is in the second position, a greater fluid flow rate is allowed through the valve seat 62. To improve the sealing / closing of the valve seat 62 when needed, the valve member 72 may be disposed within the fluid channel 60, or connected to the armature 14 to move with the armature 14, or received in the channel 60 independently of the armature. In embodiments where the valve member 72 is independently received within the passage 60, the valve member 72 may function as a check valve to prevent reverse flow from one or more outlets 68 to one or more inlets 66, and it may improve the closing and sealing of the valve seat 62. The valve member 72 may be formed of any suitable material and may be generally circular, and its dimensions are configured to be received in the fluid passage 60 and engage the valve seat 62. Alternatively, the armature 14 may directly engage the valve seat 62 without providing any separate valve member 72.

[0017] A biasing member, such as spring 74, can be received within the winding tube passage 24, and one end of the biasing member engages with armature 14, which may have a reduced diameter at end 76, on which a portion of spring 74 is received. Spring 74 biases armature 14 toward valve seat 62 such that valve member 72 is normally engaged with valve seat 62 and valve 10 is normally closed. That is, unless armature 14 is moved away from valve seat 62 by the magnetic force generated by the solenoid, spring 74 pushes armature 14 into valve member 72, which engages and closes valve seat 62 to suppress or prevent fluid flow through valve seat 62.

[0018] To control the spring force acting on armature 14 (e.g., to provide desired compression of spring 74) and / or to define a second position of armature 14 (e.g., by limiting movement of armature 14 away from valve seat 62), armature stop 80 is aligned with and may be at least partially disposed within winding tube passage 24. Armature stop 80 may close the open end of winding tube passage 24, provide a reaction surface for spring 74, and provide a stop surface that can be engaged by armature 14 to limit its travel. Armature stop 80 may include a spring retaining feature, such as a reduced-diameter rod 82 at one end, received within spring 74 and passage 24. Spring 74 may be otherwise retained between armature 14 and armature stop 80, for example, by having the end of the spring received within a cavity in adjacent ends of these components. In the example shown, a seal, such as O-ring 84, is received around the enlarged head 86 of armature stop 80, which may include a groove for the seal 84. The winding tube body 22 may further include a sealing surface 88, which is engaged by a seal 84 during assembly, such as... Figure 3-5 As shown, a sealing surface 88 is defined within an annular cavity 90 surrounding the channel 24. The sealing surface 88 may be axially outside the channel 24, or, if desired, it may be defined by the surface of the channel in the winding tube body 22. A rod 82 may extend from the head 86 and may be sealed to the winding tube body 22 to suppress or prevent fluid leakage from the channel 24.

[0019] The armature stop 80 may be carried by the winding tube body 22 and / or the housing 50, for example by a second portion of the housing, shown as a cover 92, which fits into and closes the open end of the main portion of the housing 50. The head 86 may include retaining features, such as outwardly extending barbs or one or more ribs, to engage the cover 92 (and / or the winding tube) and maintain the position of the armature stop 80 relative to the cover 92.

[0020] The cap 92 may be complementary in shape to the upper ends of the housing 50 and the winding tube 20, and may be press-fitted or otherwise secured to the housing 50 as needed, such as by one or more fasteners, clips, adhesives, welding, threading, or heat fusion. If desired, the winding tube body 22 may be securely held between the cap 92 and the base 56 to maintain a consistent position of the winding tube 20 and reduce vibration between the winding tube 20 and the housing 50. In the example shown, flanges 26, 28 may be received abutting against the cap 92 and the base 56. The cap 92 may include an opening 94 aligned with the winding tube passage 24, and the armature stop 80 is at least partially received in the opening 94. The opening 94 may be sized to achieve an interference fit with the head 86 of the armature stop 80, thereby maintaining the desired position of the armature stop 80 relative to the cap 92. Although the head 86 and the opening 94 are shown as cylindrical, they may have any desired shape and size. Alternatively, the armature stop 80 and the cover 92 may be integrally formed in a single body, or the cover may be molded over the armature stop, thus integrating them into a single component.

[0021] During assembly, the armature stop 80 can be initially assembled to the cover 92 in a first position, in which the armature stop 80 is only partially pressed into the cover 92, such as... Figure 1 , Figure 3 and Figure 4 As shown. Then, the cover 92 and the partially pressed-in armature stop 80 can be assembled into the housing 50, as shown. Figure 4 As shown. Alternatively, the cover 92 may be fitted to the housing 50 before the armature stop 80 is pressed into the cover 92 to the first position. In the first position, the armature stop 80 extends into the winding tube passage 24, the armature 14 is received between the armature stop 80 and the valve seat 62, the spring 74 is received between the armature stop 80 and the armature 14, and the armature stop 80 engages the spring 74 to at least slightly compress the spring and provide a biasing force on the armature 14. The seal 84 may also engage the winding tube sealing surface 88 to provide a fluid-impermeable seal between the armature stop 80 and the winding tube body 22. The press fit between the armature stop 80 and the cover 92 can provide a fluid-impermeable seal between them. Moreover, the seal 96 may be disposed between the winding tube body 22 and the housing 50, for example between the flange 28 and the base 56, or between the protrusions 98 of the winding tube body 22 received within the boss 64. Therefore, even if the armature stop 80 is not (or may not) in its final position, all fluid seals can be in the proper position if needed.

[0022] With the armature stop 80 in the first position and the cover 92 assembled to the housing, the solenoid valve 10 can be connected to a power source and a fluid source that can supply a gas or liquid flow to the inlet 66 of the solenoid valve 10. The power source and fluid source can be part of a fixture or workbench, and the solenoid valve 10 can be temporarily connected to the workbench to allow for valve calibration. Alternatively, the power source and fluid source can be part of a final assembly including the solenoid valve 10 (e.g., this could be the final installation position of the solenoid valve for its intended end use). That is, the solenoid valve 10 can be calibrated either before its final installation for its intended end use or while in its final installation position.

[0023] To calibrate valve 10, coil 12 is energized, and the resulting magnetic field displaces armature 14 from valve seat 62 toward armature stop 80. The travel of armature 14 can be limited by direct engagement of armature 14 with armature stop 80 (e.g., contact with the free end of rod 82), or by compressing spring 74 to a point where the spring force equals the magnetic force on armature 14. With armature 14 displaced from valve seat 62, fluid can be supplied to inlet 66, and the fluid flow out of outlet(s) 68 can be determined. Because armature stop 80 is not fully pressed into cover 92, it can be in a first position further away from valve seat 62, and armature 14 is thus allowed to move further away from valve seat 62 than ultimately desired. As a result, the fluid flow through outlet(s) 68 is greater than ultimately desired. To reduce the outlet fluid flow, the armature stop 80 is further pressed against the armature 14 and the valve seat 62 (e.g., the armature stop 80 moves relative to the stationary cover 92) to reduce the distance between the armature 14 and the valve seat 14 when the armature is in the second position, such as... Figure 5 As shown. In at least some embodiments, this can be done when fluid flow is actively supplied to valve 10 and when coil 12 is energized. Alternatively, fluid flow can be stopped before armature stop 80 is further pressed, and then fluid can be supplied again after pressing to determine whether the desired outlet flow rate has been achieved with the current armature stop position at that time.

[0024] Therefore, the second position of the armature 14 is controlled by the position of the armature stop 80, which can be adjusted on each individual solenoid valve 10 to provide the desired flow rate. During the production operation of the solenoid valve 10, the components constituting the solenoid valve vary. By controlling the armature position based on the actual flow rate of the fluid through the solenoid valve 10, rather than based on the predetermined position of the armature stop 80, variations in the output flow rate from the solenoid valve during its production operation can be significantly reduced or eliminated.

[0025] Therefore, the assembly method for the solenoid valve 10 may include positioning the armature stop 80 in a first calibration position, in which a greater-than-desired armature movement away from the valve seat 62 is permitted. The method may also include moving the armature stop 80 toward the armature 14 and the valve seat 62 to a second calibration position, in which a desired fluid flow rate from the solenoid valve 10 is obtained. Of course, the fluid flow rate may be a range rather than an exact value, and this range may be determined under one or more inlet fluid conditions (e.g., flow rate and pressure). In addition to or instead of moving the armature stop 80 relative to the cover 92, the cover 92 may be moved relative to the housing 50 or the winding tube 20, which effectively moves the armature stop 80 toward the armature 14. Therefore, the assembly step of moving the armature stop 80 toward the armature 14 or the valve seat 62 can be achieved by moving the component to which the armature stop 80 is connected (e.g., a cover, which may be integrated with or integrally formed with the cover), or by moving the component that otherwise causes such movement of the armature stop 80. Furthermore, although the armature or cover can move linearly relative to the valve seat, this can be achieved by rotating the cover relative to the housing or rotating the armature stop relative to the cover, for example, by using a thread that provides axial displacement of the rotating component to change the position of the armature stop relative to the valve seat. Rotation in one direction moves the armature stop toward the valve seat, while rotation in the opposite direction moves the armature stop away from the valve seat.

[0026] Furthermore, while the above assembly method describes a first position and a second position for the armature stop 80, with the first position located at a first distance from the valve seat 62 and the second position closer to the valve seat 62 than the first position, the reverse is also possible. That is, the armature stop 80 can be initially positioned closer to the valve seat 62 than the desired final position, and then moved away from the valve seat 62. Alternatively, the armature stop 80 can be initially positioned in a first position, which is intended to provide a desired flow rate from the valve 10, and then moved only if it is determined that the flow rate differs from the desired flow rate. Furthermore, instead of measuring the outlet flow rate, one or more different fluid flow characteristics can be determined, and the final position of the armature stop can be selected based on these fluid flow characteristics. For example, pressure at(one or more) the outlet, pressure at the inlet, or pressure upstream of the inlet, or pressure drop across the valve seat (e.g., pressure difference between the inlet and outlet) can be used instead of the fluid outlet or inlet flow rate. Alternatively, pressure at(one or more) the outlet, pressure at the inlet, or pressure upstream of the inlet, or pressure drop across the valve seat (e.g., pressure difference between the inlet and outlet) can be used in addition to the fluid outlet or inlet flow rate. Thus, a method may include the step of moving armature stop 80 relative to valve seat 62 if the fluid flow characteristic is outside a predetermined threshold value of the fluid flow characteristic, wherein the threshold value can be a minimum, maximum, or range of values ​​for one or more fluid flow characteristics. Valve 10 can be used in a wide range of applications to control liquid and / or gas flows, such as, but not limited to, controlling fuel or air flows in combustion engine applications (e.g., controlling fuel and / or air flows in a carburetor, or as a fuel injector through which pressurized fuel is supplied to the engine).

[0027] It should be understood that the foregoing description is not intended to limit the invention, but rather to describe one or more preferred embodiments of the invention. The invention is not limited to the specific embodiments disclosed herein, but is defined solely by the appended claims. Furthermore, the statements contained in the foregoing description relate to specific embodiments and should not be construed as limiting the scope of the invention or the definition of terms used in the claims, unless the terms or phrases are expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiments will become apparent to those skilled in the art. For example, methods with more, fewer, or different steps than the methods shown may be used alternatively. All such embodiments, variations, and modifications are contemplated to fall within the scope of the appended claims.

[0028] As used in this specification and claims, the terms “for example,” “such as,” “like,” “e.g.,” “as,” and “etc.,” as well as the verbs “comprising,” “having,” “including,” and other verb forms thereof, when used in conjunction with a list of one or more parts or other items, are to be interpreted as open-ended, meaning that the list is not considered to exclude other additional parts or items. Other terms should be interpreted using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.

Claims

1. A method of assembling an electromechanical valve, wherein, The electromechanical valve is calibrated prior to final installation of the valve for its intended end use or while in its final installed position, the method comprising: positioning an armature stop in a first position at a first distance from a valve seat, an armature being between the armature stop and the valve seat; actuating the electromechanical valve to move the armature away from the valve seat and into engagement with the armature stop; providing a fluid flow to the electromechanical valve; determining a fluid flow characteristic; and moving the armature stop relative to the valve seat to a second position at a distance different from the first distance as a function of the fluid flow characteristic, wherein the armature stop is press fit to a portion of a housing, the portion of the housing is press fit to the housing, and the step of moving the armature stop is accomplished by moving the armature stop relative to the portion of the housing or moving the portion of the housing to which the armature stop is press fit, wherein the armature stop is at least partially received in an opening of the portion of the housing, and wherein the opening is sized to interference fit with the armature stop to enable a desired position of the armature stop relative to the portion of the housing to be maintained.

2. The method of claim 1, wherein, The step of moving the armature stop is accomplished by moving the armature stop without moving another component of the electromechanical valve.

3. The method of claim 1, wherein, The step of moving the armature stop is accomplished by moving a component to which the armature stop is coupled.

4. The method of claim 1, wherein, The step of moving the armature stop is performed while fluid is flowing through the electromechanical valve.

5. The method of claim 1, wherein, The step of moving the armature stop is performed while fluid is not flowing through the electromechanical valve, and the method further comprises the step of determining the fluid flow characteristic after the armature stop has been moved.

6. The method of claim 1, wherein, The fluid flow characteristic is one or more of the following: a fluid flow rate through one or more outlets of the electromechanical valve, a fluid flow rate through one or more inlets of the electromechanical valve, a fluid pressure at one or more of the inlets, and a fluid pressure at one or more of the outlets.

7. The method of claim 1, wherein, The electromechanical valve comprises a housing and a cover, and the armature stop is press fit to the cover, and wherein the cover is coupled to the housing to close an open end of the housing.

8. The method of claim 7, wherein, The electromechanical valve comprises a bobbin having a channel, the bobbin being received within the housing, and the armature is received within the channel, and a portion of the armature stop is received within the channel, and the step of moving the armature stop is accomplished by moving the armature stop within the channel and relative to the bobbin.

9. A method of assembling an electromechanical valve, wherein, The electromechanical valve is calibrated prior to final installation of the valve for its intended end use or while in its final installed position, the method comprising: positioning an armature stop in a first position at a first distance from a valve seat, an armature being between the armature stop and the valve seat; actuating the electromechanical valve to move the armature away from the valve seat and into engagement with the armature stop; providing a fluid flow to the electromechanical valve; determining a fluid flow characteristic; and moving the armature stop relative to the valve seat to a second position at a distance different from the first distance as a function of the fluid flow characteristic, wherein the armature stop is press fit to a portion of a housing, the portion of the housing is press fit to the housing, and the step of moving the armature stop is accomplished by moving the armature stop relative to the portion of the housing or moving the portion of the housing to which the armature stop is press fit, wherein the armature stop is at least partially received in an opening of the portion of the housing, and wherein the opening is sized to interference fit with the armature stop to enable a desired position of the armature stop relative to the portion of the housing to be maintained. actuating the electromechanical valve to move the armature away from the valve seat and into engagement with the armature stop; providing a fluid flow to the electromechanical valve; determining a fluid flow characteristic; and if the fluid flow characteristic is outside of a predetermined threshold of the fluid flow characteristic, moving the armature stop relative to the valve seat, wherein the armature stop is press fit to a portion of a housing, the portion of the housing is press fit to the housing, the step of moving the armature stop is accomplished by moving the armature stop relative to the portion of the housing or moving the portion of the housing to which the armature stop is press fit, wherein the armature stop is at least partially received in an opening of the portion of the housing, and wherein the opening is sized to press fit the armature stop to maintain a desired position of the armature stop relative to the portion of the housing.

10. The method of claim 9, comprising: providing a housing and providing a cover, the armature is received in the housing; fitting the armature stop to the cover; and assembling the cover to the housing to position the armature stop in the first position.

11. The method of claim 10, wherein, The step of moving the armature stop is accomplished by moving the cover relative to the housing or moving the armature stop relative to the cover or both.

12. The method of claim 9, wherein, The step of moving the armature stop is accomplished by linearly moving the armature stop or rotating the armature stop.

13. The method of claim 9, wherein, The armature stop is further from the valve seat in the first position than after the step of moving the armature stop.

14. The method of claim 10, wherein, The armature stop is coupled to the cover by a press fit, and the step of fitting the armature stop to the cover is accomplished by pressing the armature stop into an opening of the cover.

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