US20130277586A1 - Control valve with area independent pressure sensing - Google Patents
Control valve with area independent pressure sensing Download PDFInfo
- Publication number
- US20130277586A1 US20130277586A1 US13/449,960 US201213449960A US2013277586A1 US 20130277586 A1 US20130277586 A1 US 20130277586A1 US 201213449960 A US201213449960 A US 201213449960A US 2013277586 A1 US2013277586 A1 US 2013277586A1
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- United States
- Prior art keywords
- valve
- valve element
- bore
- armature
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
- F16K31/06—Actuating devices; Operating means; Releasing devices electric; magnetic using a magnet, e.g. diaphragm valves, cutting off by means of a liquid
- F16K31/0686—Braking, pressure equilibration, shock absorbing
- F16K31/0696—Shock absorbing, e.g. using a dash-pot
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
- F16K31/06—Actuating devices; Operating means; Releasing devices electric; magnetic using a magnet, e.g. diaphragm valves, cutting off by means of a liquid
- F16K31/0603—Multiple-way valves
- F16K31/061—Sliding valves
- F16K31/0613—Sliding valves with cylindrical slides
Definitions
- the present invention relates to solenoid operated hydraulic valves; and in particular to such valves in which pressure acting on an end of a spool creates a force that must be overcome by the solenoid in order to move the spool.
- Control valves have been developed for a variety of equipment to selectively apply and exhaust pressurized fluid to and from a component, the operation of which is controlled by that valve.
- one such valve 200 has a spool 202 , that slides within a bore 204 in response to operation of a solenoid actuator 206 .
- the spool 202 opens to provide a path between a supply port 208 conveying pressurized fluid and a workport 210 , which is connected to the component being operated by the valve. This provides pressurized fluid to the component being operated by the valve.
- a control valve has a valve body with a fluid passage therein and a first port, a second port, and a workport open into the fluid passage.
- a valve element such as a spool, for example, is moveably received within the fluid passage for selectively controlling the flow of fluid between the workport and each of the first and second ports.
- a solenoid actuator includes a moveable armature that is operatively coupled to move the valve element.
- the valve element has first and second ends with a valve element bore extending inwardly from the first end. Pressure from the workport is applied to the first end of the valve element, thereby creating a first force that acts on the valve element. A solid slug is received within the valve element bore and the workport pressure also produces a second force that act on the slug. The slug is operatively coupled to transfer the second force to a stationary part of the control valve without the second force being applied to the valve element.
- the solid slug preferably remains stationary with respect to the valve body as the valve element slides within the fluid passage bore.
- valve element comprises a slot opening into the valve element bore.
- a pin projects through the slot and engages the slug and at least one of the valve body and the solenoid actuator.
- FIG. 1 is a cross sectional view through a first electrohydraulic control valve according to the present invention in which a workport is normally connected to an exhaust port in a deactivated state of the valve;
- FIG. 2 is a view of one end of a valve element that is part of the first electrohydraulic control valve
- FIG. 3 is a graph depicting the relationship between the velocity at which an armature and the valve element move and the damping force provided by a damping element in the control valve;
- FIG. 4 is a cross sectional view through a valve element, that incorporates an alternative damping element to the one shown in FIG. 1 ;
- FIG. 5 is a plane view of the alternative damping device
- FIG. 6 is a cross sectional view through a second electrohydraulic control valve, according to the present invention, which normally connects the workport to a pressurized fluid supply port;
- FIG. 7 is a cross sectional view through a previously known electrically operated control valve.
- references herein to directional movement such as left or right, refer to the motion of the components in the orientation illustrated in the drawings, which may not be the orientation of the components or the present control valve when attached to a machine.
- an electrohydraulic first control valve 30 is illustrated inserted into an aperture 22 in a manifold 20 .
- the manifold 20 has a supply passage 23 that conveys pressurized fluid from a source such as a pump (not shown) and a return passage 24 that conveys fluid back to a tank (not shown).
- the manifold 20 also has a device passage 26 to which is connected to a hydraulic component that is controlled by the first control valve 30 .
- the first control valve 30 has a tubular valve body 32 with a longitudinal bore 34 and transverse openings which provide ports between the manifold passages and the longitudinal bore. Specifically, the longitudinal bore 34 is connected by a supply port 36 to the supply passage 23 and by an exhaust port 38 to the return passage 24 . A workport 40 at the nose of the tubular valve body 32 opens into the manifold device passage 26 .
- a spool-like, tubular valve element 44 is slideably received within the bore 34 of the valve body 32 and is moved therein by a solenoid actuator 60 .
- a central bore 48 extends between the opposite ends of the valve element.
- a plurality of radial apertures 46 communicate with the valve element bore 48 which forms a fluid passage, so that in selective positions of the valve element fluid paths are provided between the workport 40 and either the supply port 36 or the exhaust port 38 .
- the flow to and from the workport goes through the center of the valve element.
- the first control valve 30 is referred to as having a “normally low pressure state” because in the deactivated state the workport 40 is connected to the exhaust port 38 .
- the workport pressure acts on the adjacent end surface of the valve element and typically the entire circular end surface area of previous valve elements. That also is the case where the valve element bore is a blind aperture opening only at the end of the valve element facing the workport, in which case the pressure also acts in the interior end surface of that bore. Even in designs in which the valve element bore extends completely through the valve element, the workport pressure reaching the opposite end often acts on the solenoid actuator that operates the valve, thereby having the same effect on valve operation as with a blind valve element bore. In all these designs, the solenoid actuator has to overcome the feedback force that results from the workport pressure acting on that valve element surface area.
- a drawback of these designs is that in order to control a greater amount of fluid flow, a larger valve element is required which results in a larger feedback force from the workport pressure acting on the valve element.
- the larger feedback force in turn requires greater counter force from the solenoid to move the valve element, thus requiring a larger solenoid.
- the present valve element arrangement eliminates a need for a significantly larger solenoid in order to design a valve with a larger flow capability. This is accomplished by designing a tubular valve element 44 wherein the force from the workport pressure acts only on an annular end surface 49 of the valve element.
- the area of that annular end surface 49 does not increase significantly as the size of the valve element is increased to handle greater flow.
- the surface area on which the workport pressure acts remains relatively unchanged. Therefore, the size of the solenoid actuator 60 can remain the same or at least does not have to increase as significantly to operate a larger flow capacity valve element.
- a slug 54 of solid material within the valve element 44 and transferring the pressure force acting on the slug to a stationary part of the valve structure and not to the valve element.
- the slug 54 is located within the valve element bore 48 and has an outer diameter slightly less than the diameter of that valve element bore, so as to allow the valve element 44 to slide over the slug.
- a tab 56 extends from one end of the slug 54 and has an aperture there through.
- a cross pin 52 extends through that aperture and through elongated slots 50 near the end of the valve element 44 that is remote from the workport 40 . The length of the slots 50 allows the valve element 44 to slide unobstructed within the valve body bore 34 , as will be described.
- the slug 54 reduces the surface area on which pressure acts on the valve element 44 to the area between the outer diameter D 1 of the valve element and the outer diameter D 2 of the slug. This results in an annular surface area at the end 49 of the valve element 44 that faces the workport for pressure to act upon.
- the surface area on which the pressure at the workport 40 acts on the valve element has been reduced from the entire circular cross sectional surface area to just this annular surface area.
- the force exerted on the valve element 44 due to the pressure is directly related to the surface area on which the pressure acts and that force must be overcome by the solenoid actuator 60 to move the valve element.
- valve element arrangement in which the pressure acted on the entire cross sectional surface area of the valve element, as the size of the valve element was increased in order to control a larger fluid flow the force due to that pressure increased proportionally.
- a larger solenoid actuator was required to overcome that greater force and move the valve element.
- the size of the valve element 44 is increased for a higher flow capacity valve, so too is the size of the slug 54 increased. Therefore, the size of the annular end surface 49 of the valve element 44 does not increase as significantly and may even remain relatively the same by increasing the size of the slug disproportionally to the valve element size increase.
- the present valve element arrangement enables the valve element size to be increased without any or at least without a significant increase in the size of the solenoid actuator 60 .
- the solenoid actuator 60 includes a can-like metal case 61 that contains an electromagnetic coil 62 which is wound on a non-magnetic bobbin 63 , preferably formed of a plastic.
- a magnetically conductive first pole piece 64 has a cylindrical, tubular section 66 which extends into one end of the bobbin 63 .
- a magnetically conductive, second pole piece 68 extends into the opposite end of the bobbin 63 and has an interior end that is spaced from the first pole piece 64 .
- the second pole piece 68 has an outwardly projecting flange 70 that extends across the open end of the metal case 61 which is crimped around part of the valve body 32 .
- the metal case 61 and the second pole piece 68 form a housing of the solenoid actuator 60 .
- the engagement of the metal case 61 with the first and second pole pieces 64 and 68 provides a highly conductive magnetic flux path within the electromagnetic coil 62 .
- An armature 72 within the solenoid actuator 60 is slideably received within the first and second pole pieces 64 and 68 .
- One end of the armature 72 defines a first chamber 81 within the second pole piece 68 and the opposite end of the armature defines a second chamber 82 within the first pole piece 64 .
- These chambers fill with the fluid that flows through the control valve.
- the armature 72 slides within the first and second pole pieces 64 and 68 in response to a magnetic field that is produced by applying electric current to the electromagnetic coil 62 via a connector 65 .
- the electromagnetic coil 62 may be driven by a pulse width modulated (PWM) signal having a duty cycle that is varied in order to position the valve element 44 within the pole pieces.
- PWM pulse width modulated
- the armature 72 engages a driver tube 73 that is formed of a non-magnetic material and abuts the interior end of the valve element 44 . Therefore, application of the electric current to the electromagnetic coil 62 moves the armature 72 to the right in FIG. 1 , thereby pushing the valve element 44 to the right.
- the armature 72 has a bore 74 extending between opposite ends, thereby forming a fluid passage between the first and second chambers 81 and 82 .
- the armature bore 74 has a section adjacent the end that faces the valve element 44 which has a reduced diameter thereby forming an armature aperture 75 .
- a digressive damping element 76 is located within that armature aperture 75 and is able to slide longitudinally therein.
- a spring 80 is within the armature bore 74 and has a first end affixed to the damping element 76 .
- at one end of the spring 80 is a first section 84 of coil turns with a smaller diameter than a second section 85 of coil turns in the center of the spring.
- the coil turns in the first section 84 are wrapped around a tab with a head that projects from the main body of the digressive damping element 76 .
- a third section 86 of coil turns at an opposite end of the spring 80 has larger diameter than the center second section 85 .
- the coil turns of the third section 86 are press fitted into the armature bore 74 and thereby are held stationary in the bore at that position.
- the spring 80 centers the damping element within the armature aperture 75 .
- the spring 80 exerts both tension and compression forces, which allow the damping element 76 to move bidirectionally in response to a pressure differential across the damping element.
- a first flute 77 extends partway along the exterior surface of the digressive damping element 76 from the end facing the valve element 44 .
- the first flute 77 only communicates with the first chamber 81 and does not open into the armature bore 74 .
- a second flute 78 extends partway along the exterior surface of the damping element 76 from the end that is in the armature bore 74 .
- the second flute 78 only communicates with the armature bore 74 and does not open into the first chamber 81 .
- the damping element 76 when centered in the armature aperture 75 , the damping element 76 does not provide a significant fluid path between the two armature chambers 81 and 82 .
- the flutes may be replaced by flat regions on the exterior surface of the damping element. With either version, the flutes or flats form passageways in the exterior surface of the damping element 76 .
- a conical coil spring 45 is located adjacent the workport 40 .
- a small diameter end of the conical coil spring 45 engages the end of the valve element 44 and the larger end of the spring is held within the bore 34 of the valve body 32 by a retaining ring 47 .
- the conical coil spring 45 biases the valve element into the illustrated normal position when current is not being applied to the solenoid actuator 60 . In that illustrated position, the apertures 46 in the valve element open into the exhaust port 38 , thereby providing a path between the exhaust port and the workport 40 when the valve is in the de-energized state.
- the volume of one of the chambers 81 or 82 is expanding while the volume of the other chamber is correspondingly decreasing.
- fluid within the chamber that is decreasing in volume must flow into the expanding chamber.
- that motion will increase the pressure of the fluid within the first chamber 81 and decrease the pressure in the second chamber 82 , producing a difference in pressure that acts on the damping element 76 .
- the fluid in the first chamber 81 can only flow into the second chamber 82 around the closed damping element 76 and between the armature 72 and the two pole pieces 64 and 68 .
- first control valve 30 having relatively high damping rates at low armature velocities and significantly lower damping rates at higher armature velocities, which is referred to as “digressive damping.”
- a “digressive damping element” is a component of a valve than damps the motion of the valve element according to that velocity-force relationship.
- a similar digressive damping operation occurs when the electric current is removed from the electromagnetic coil 62 and the valve element 44 and armature 72 move to the left due to the force of the conical coil spring 45 and the workport pressure. At that time, fluid is forced out of the second chamber 82 into the first chamber 81 . If the armature 72 moves rapidly enough, the pressure in the second chamber 82 reaches a point at which the damping element 76 moves sufficiently far to the right where the second flute 78 opens a path from the armature bore 74 into the first chamber 81 . This operation produces a similar damping curve as illustrated in FIG. 3 . Therefore the first control valve exhibits digressive damping in both directions of operation.
- FIG. 4 illustrates a second type of an armature 90 which has an alternative digressive damping element 92 .
- This armature 90 has a longitudinal bore 91 extending between both ends of the armature.
- One end of the longitudinal bore 91 has an enlarged opening in which a flat, disk-shaped damping element 92 is held by a snap-type retaining ring 93 .
- the disk-shaped damping element 92 has a U-shaped slot 94 extending there through and centrally located therein.
- the slot 94 forms a flap 96 .
- FIG. 6 illustrates a second control valve 100 in which components that are the same as those in the first control valve 30 have been assigned identical reference numerals. To simplify the description herein, those components will not be described in detail again.
- the second control valve 100 has a normally high pressure state, meaning that when electric current is not being applied to the electromagnetic coil 62 , the valve element 102 is biased into a position in which a path is formed between the pressurized fluid supply port 36 and the workport 40 . As a consequence, the valve element 102 is slightly different so that the apertures 104 that extend outward from the central bore 106 are located to communicate with the supply port 36 in that de-energized state. The valve element 102 directly abuts the armature 110 .
- the armature 110 also is slightly different in that the armature aperture 114 is located in the midsection of the armature bore 112 .
- the cylindrical digressive damping element 116 located in the armature aperture 114 , is biased by a damping spring 118 connected to the side of the damping element that faces the valve element 102 .
- the damping spring 118 is identical to the previously described damping spring 80 for the first control valve 30 and is secured to the damping element and in the armature bore 112 in the same ways.
- An armature spring 120 biases the armature 110 away from the exterior end of the solenoid actuator 60 so as to push the armature and the valve element 102 into the normally high pressure state of the valve that is illustrated.
- a spring adjustment cup 122 is press fitted into an aperture in the first pole piece 124 by an amount that sets the force which the armature spring 120 exerts on the armature 110 .
- a second pole piece 126 provides an interior cylindrical surface against which the armature 110 slides.
- valve element 102 may be maintained in this closed position.
- Application of a greater level of electric current to the electromagnetic coil 62 enables the armature 110 and the valve element 102 to move farther leftward into a position at which the apertures 104 in the valve element open into the exhaust port 38 .
- fluid is forced to flow between the first and second solenoid chambers 81 and 82 .
- the direction of that flow depends upon the direction in which the armature 110 is moving. For example, when the armature 110 moves to the left in FIG. 6 , fluid is forced from the second chamber 82 into the first chamber 81 . Initially the fluid flows only around the outside of the armature 110 and through its bore 112 past the closed digressive damping element 116 . As the pressure within the second solenoid chamber 82 increases due to greater velocity of the armature 110 , the force exerted on the end of the damping element 116 that faces the second chamber 82 increases.
- the force of the armature spring 120 returns the armature 110 and the abutting valve element 102 to the normal position illustrated in FIG. 6 .
- the pressure differentials produced in chamber 81 and 82 by the armature motion are similar to but reversed from those produced when the electromagnetic coil was energized.
- the digressive damping element 116 operates in a reverse manner, damping the fluid flow from the first chamber 81 into the second chamber 82 . Therefore the damping element 116 provides digressive damping of the bidirectional movement of the armature 110 and valve element 102 in the second control valve 100 .
- disk-type digressive damping element 92 shown in FIG. 5 could be substituted for the cylindrical damping element 116 in the second control valve 100 .
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Abstract
Description
- Not Applicable
- Not Applicable
- 1. Field of the Invention
- The present invention relates to solenoid operated hydraulic valves; and in particular to such valves in which pressure acting on an end of a spool creates a force that must be overcome by the solenoid in order to move the spool.
- 2. Description of the Related Art
- Control valves have been developed for a variety of equipment to selectively apply and exhaust pressurized fluid to and from a component, the operation of which is controlled by that valve. As shown in
FIG. 7 , onesuch valve 200 has aspool 202, that slides within abore 204 in response to operation of asolenoid actuator 206. Thespool 202 opens to provide a path between asupply port 208 conveying pressurized fluid and aworkport 210, which is connected to the component being operated by the valve. This provides pressurized fluid to the component being operated by the valve. - In many applications relatively high pressure acts on an
end 212 of the spool and typically the entire cross sectional area of the spool. Some spools have a centralblind bore 214 extending inwardly from that end. The workport pressure then acts on theannular end surface 216 and the parallel surface 218 at the inner end of the bore. In order to move the spool, the solenoid actuator has to overcome the force that results from the workport pressure acting on the combined valveelement surface area 216 and 218. - As a consequence, if a larger spool is required to control the proper amount of flow, the larger surface area of the spool results in a greater feedback force. The greater feedback force in turn requires a greater counter force from a larger solenoid actuator. Therefore, it would be desirable to be able to increase the size of the spool to control a greater amount of flow without also having to increase the size of the solenoid actuator.
- A control valve has a valve body with a fluid passage therein and a first port, a second port, and a workport open into the fluid passage. A valve element, such as a spool, for example, is moveably received within the fluid passage for selectively controlling the flow of fluid between the workport and each of the first and second ports. A solenoid actuator includes a moveable armature that is operatively coupled to move the valve element.
- The valve element has first and second ends with a valve element bore extending inwardly from the first end. Pressure from the workport is applied to the first end of the valve element, thereby creating a first force that acts on the valve element. A solid slug is received within the valve element bore and the workport pressure also produces a second force that act on the slug. The slug is operatively coupled to transfer the second force to a stationary part of the control valve without the second force being applied to the valve element.
- In one aspect of the present invention, the solid slug preferably remains stationary with respect to the valve body as the valve element slides within the fluid passage bore.
- In another aspect of the present invention, the valve element comprises a slot opening into the valve element bore. A pin projects through the slot and engages the slug and at least one of the valve body and the solenoid actuator.
-
FIG. 1 is a cross sectional view through a first electrohydraulic control valve according to the present invention in which a workport is normally connected to an exhaust port in a deactivated state of the valve; -
FIG. 2 is a view of one end of a valve element that is part of the first electrohydraulic control valve; -
FIG. 3 is a graph depicting the relationship between the velocity at which an armature and the valve element move and the damping force provided by a damping element in the control valve; -
FIG. 4 is a cross sectional view through a valve element, that incorporates an alternative damping element to the one shown inFIG. 1 ; -
FIG. 5 is a plane view of the alternative damping device; -
FIG. 6 is a cross sectional view through a second electrohydraulic control valve, according to the present invention, which normally connects the workport to a pressurized fluid supply port; and -
FIG. 7 is a cross sectional view through a previously known electrically operated control valve. - References herein to directional movement, such as left or right, refer to the motion of the components in the orientation illustrated in the drawings, which may not be the orientation of the components or the present control valve when attached to a machine.
- With initial reference to
FIG. 1 , an electrohydraulicfirst control valve 30 is illustrated inserted into anaperture 22 in amanifold 20. Themanifold 20 has asupply passage 23 that conveys pressurized fluid from a source such as a pump (not shown) and areturn passage 24 that conveys fluid back to a tank (not shown). Themanifold 20 also has adevice passage 26 to which is connected to a hydraulic component that is controlled by thefirst control valve 30. - The
first control valve 30 has atubular valve body 32 with alongitudinal bore 34 and transverse openings which provide ports between the manifold passages and the longitudinal bore. Specifically, thelongitudinal bore 34 is connected by asupply port 36 to thesupply passage 23 and by anexhaust port 38 to thereturn passage 24. Aworkport 40 at the nose of thetubular valve body 32 opens into themanifold device passage 26. - A spool-like,
tubular valve element 44 is slideably received within thebore 34 of thevalve body 32 and is moved therein by asolenoid actuator 60. Acentral bore 48 extends between the opposite ends of the valve element. A plurality ofradial apertures 46 communicate with the valve element bore 48 which forms a fluid passage, so that in selective positions of the valve element fluid paths are provided between theworkport 40 and either thesupply port 36 or theexhaust port 38. In this type of proportional control valve, the flow to and from the workport goes through the center of the valve element. Thefirst control valve 30, is referred to as having a “normally low pressure state” because in the deactivated state theworkport 40 is connected to theexhaust port 38. - The workport pressure acts on the adjacent end surface of the valve element and typically the entire circular end surface area of previous valve elements. That also is the case where the valve element bore is a blind aperture opening only at the end of the valve element facing the workport, in which case the pressure also acts in the interior end surface of that bore. Even in designs in which the valve element bore extends completely through the valve element, the workport pressure reaching the opposite end often acts on the solenoid actuator that operates the valve, thereby having the same effect on valve operation as with a blind valve element bore. In all these designs, the solenoid actuator has to overcome the feedback force that results from the workport pressure acting on that valve element surface area.
- As noted previously, a drawback of these designs is that in order to control a greater amount of fluid flow, a larger valve element is required which results in a larger feedback force from the workport pressure acting on the valve element. The larger feedback force in turn requires greater counter force from the solenoid to move the valve element, thus requiring a larger solenoid. The present valve element arrangement eliminates a need for a significantly larger solenoid in order to design a valve with a larger flow capability. This is accomplished by designing a
tubular valve element 44 wherein the force from the workport pressure acts only on anannular end surface 49 of the valve element. By judiciously designing the inner and outer diameters of thevalve element 44, the area of thatannular end surface 49 does not increase significantly as the size of the valve element is increased to handle greater flow. Thus the surface area on which the workport pressure acts remains relatively unchanged. Therefore, the size of thesolenoid actuator 60 can remain the same or at least does not have to increase as significantly to operate a larger flow capacity valve element. - This is accomplished by placing a
slug 54 of solid material within thevalve element 44 and transferring the pressure force acting on the slug to a stationary part of the valve structure and not to the valve element. In particular, theslug 54 is located within the valve element bore 48 and has an outer diameter slightly less than the diameter of that valve element bore, so as to allow thevalve element 44 to slide over the slug. Atab 56 extends from one end of theslug 54 and has an aperture there through. Across pin 52 extends through that aperture and throughelongated slots 50 near the end of thevalve element 44 that is remote from theworkport 40. The length of theslots 50 allows thevalve element 44 to slide unobstructed within the valve body bore 34, as will be described. End sections of thecross pin 52 are held between thevalve body 32 and thesolenoid actuator 60 which thereby holds theslug 54 in a fixed position relative to the valve body. In other words, as thevalve element 44 slides within the valve body bore 34, theslug 54 remains stationary. With this arrangement, the force exerted on theslug 54 of solid material, due to the workport pressure in the valve body bore 34, is transferred directly to the stationary part of the valve structure, i.e. thevalve body 32 and thesolenoid actuator 60, and is not applied to thevalve element 44. As a consequence that force does not affect the motion of the valve element. - With reference to
FIGS. 1 and 2 , theslug 54 reduces the surface area on which pressure acts on thevalve element 44 to the area between the outer diameter D1 of the valve element and the outer diameter D2 of the slug. This results in an annular surface area at theend 49 of thevalve element 44 that faces the workport for pressure to act upon. Thus the surface area on which the pressure at theworkport 40 acts on the valve element has been reduced from the entire circular cross sectional surface area to just this annular surface area. The force exerted on thevalve element 44 due to the pressure is directly related to the surface area on which the pressure acts and that force must be overcome by thesolenoid actuator 60 to move the valve element. Heretofore with previous valve element arrangements, in which the pressure acted on the entire cross sectional surface area of the valve element, as the size of the valve element was increased in order to control a larger fluid flow the force due to that pressure increased proportionally. Thus a larger solenoid actuator was required to overcome that greater force and move the valve element. With the present valve element arrangement, as the size of thevalve element 44 is increased for a higher flow capacity valve, so too is the size of theslug 54 increased. Therefore, the size of theannular end surface 49 of thevalve element 44 does not increase as significantly and may even remain relatively the same by increasing the size of the slug disproportionally to the valve element size increase. As a result, the present valve element arrangement enables the valve element size to be increased without any or at least without a significant increase in the size of thesolenoid actuator 60. - The
solenoid actuator 60 includes a can-like metal case 61 that contains anelectromagnetic coil 62 which is wound on anon-magnetic bobbin 63, preferably formed of a plastic. A magnetically conductivefirst pole piece 64 has a cylindrical,tubular section 66 which extends into one end of thebobbin 63. A magnetically conductive,second pole piece 68 extends into the opposite end of thebobbin 63 and has an interior end that is spaced from thefirst pole piece 64. Thesecond pole piece 68 has an outwardly projectingflange 70 that extends across the open end of themetal case 61 which is crimped around part of thevalve body 32. Themetal case 61 and thesecond pole piece 68 form a housing of thesolenoid actuator 60. The engagement of themetal case 61 with the first andsecond pole pieces electromagnetic coil 62. - An
armature 72 within thesolenoid actuator 60 is slideably received within the first andsecond pole pieces armature 72 defines afirst chamber 81 within thesecond pole piece 68 and the opposite end of the armature defines asecond chamber 82 within thefirst pole piece 64. These chambers fill with the fluid that flows through the control valve. Thearmature 72 slides within the first andsecond pole pieces electromagnetic coil 62 via aconnector 65. For example, theelectromagnetic coil 62 may be driven by a pulse width modulated (PWM) signal having a duty cycle that is varied in order to position thevalve element 44 within the pole pieces. Thearmature 72 engages adriver tube 73 that is formed of a non-magnetic material and abuts the interior end of thevalve element 44. Therefore, application of the electric current to theelectromagnetic coil 62 moves thearmature 72 to the right inFIG. 1 , thereby pushing thevalve element 44 to the right. - The
armature 72 has abore 74 extending between opposite ends, thereby forming a fluid passage between the first andsecond chambers valve element 44 which has a reduced diameter thereby forming anarmature aperture 75. A digressive dampingelement 76 is located within thatarmature aperture 75 and is able to slide longitudinally therein. Aspring 80 is within the armature bore 74 and has a first end affixed to the dampingelement 76. For example, at one end of thespring 80 is afirst section 84 of coil turns with a smaller diameter than asecond section 85 of coil turns in the center of the spring. The coil turns in thefirst section 84 are wrapped around a tab with a head that projects from the main body of the digressive dampingelement 76. Athird section 86 of coil turns at an opposite end of thespring 80 has larger diameter than the centersecond section 85. The coil turns of thethird section 86 are press fitted into the armature bore 74 and thereby are held stationary in the bore at that position. When equal fluid pressure levels act on both sides of the dampingelement 76, thespring 80 centers the damping element within thearmature aperture 75. Thespring 80 exerts both tension and compression forces, which allow the dampingelement 76 to move bidirectionally in response to a pressure differential across the damping element. - A first flute 77 extends partway along the exterior surface of the digressive damping
element 76 from the end facing thevalve element 44. When the dampingelement 76 is centered longitudinally within thearmature aperture 75, the first flute 77 only communicates with thefirst chamber 81 and does not open into the armature bore 74. Asecond flute 78 extends partway along the exterior surface of the dampingelement 76 from the end that is in the armature bore 74. When the dampingelement 76 is centered longitudinally within thearmature aperture 75, thesecond flute 78 only communicates with the armature bore 74 and does not open into thefirst chamber 81. Thus when centered in thearmature aperture 75, the dampingelement 76 does not provide a significant fluid path between the twoarmature chambers element 76. - A
conical coil spring 45 is located adjacent theworkport 40. A small diameter end of theconical coil spring 45 engages the end of thevalve element 44 and the larger end of the spring is held within thebore 34 of thevalve body 32 by a retainingring 47. Theconical coil spring 45 biases the valve element into the illustrated normal position when current is not being applied to thesolenoid actuator 60. In that illustrated position, theapertures 46 in the valve element open into theexhaust port 38, thereby providing a path between the exhaust port and theworkport 40 when the valve is in the de-energized state. - When electric current is applied to the
electromagnetic coil 62, a magnetic field is produced within thesolenoid actuator 60 that causes thearmature 72 to move to the right in the drawing, thereby pushing thevalve element 44 to the right as well. By applying a first level of electric current to theelectromagnetic coil 62, thearmature 72 is moved so that thevalve element apertures 46 align with aland 88 in the valve body bore 34 between thesupply port 36 and theexhaust port 38. In this position, thevalve element apertures 46 are closed so that thebore 48 of thevalve element 44 is not in communication with either the supply or theexhaust port workport 40 is closed off from the other two ports. Increasing the magnitude of electric current applied to theelectromagnetic coil 62 moves thearmature 72 and thevalve element 44 farther to the right inFIG. 1 aligning theapertures 46 with thesupply port 36. This enables fluid from the supply port to flow through theapertures 46 and the valve element bore 48 toward theworkport 40. Thereafter, when the application of electric current to theelectromagnetic coil 62 is terminated, a magnetic field no longer acts on thearmature 72. At that time, theconical coil spring 45 pushes thevalve element 44 and thus thearmature 72 leftward inFIG. 1 and into the illustrated normal position where thevalve element apertures 46 communicate with theexhaust port 38. - When the
armature 72 moves within thepole pieces chambers FIG. 1 , that motion will increase the pressure of the fluid within thefirst chamber 81 and decrease the pressure in thesecond chamber 82, producing a difference in pressure that acts on the dampingelement 76. As the armature initially moves, the fluid in thefirst chamber 81 can only flow into thesecond chamber 82 around the closed dampingelement 76 and between thearmature 72 and the twopole pieces first chamber 81 to increase rapidly as the velocity of thearmature 72 increases. This pressure increase exerts a relatively rapidly increasing the motion damping force on thearmature 72 as depicted by the graph inFIG. 3 . - If the magnitude of electric current applied to the
solenoid actuator 60 causes thearmature 72 to move a sufficiently high velocity, then significantly higher pressure will be produced in thefirst chamber 81 than in thesecond chamber 82/This difference in pressure causes the dampingelement 76 to be pushed far enough into thebore aperture 75 that the first flute 77 opens into the armature bore 74. That event occurs atpoint 89 on the damping curve inFIG. 3 . This exposure of the first flute 77 provides a sizeable path for additional fluid to flow past the dampingelement 76 from thefirst chamber 81 into thesecond chamber 82. Thereafter as the velocity of thearmature 72 continues to increase, the damping force exerted thereon by the pressure within thefirst chamber 81 increases very gradually. This results in thefirst control valve 30 having relatively high damping rates at low armature velocities and significantly lower damping rates at higher armature velocities, which is referred to as “digressive damping.” As used herein a “digressive damping element” is a component of a valve than damps the motion of the valve element according to that velocity-force relationship. - A similar digressive damping operation occurs when the electric current is removed from the
electromagnetic coil 62 and thevalve element 44 andarmature 72 move to the left due to the force of theconical coil spring 45 and the workport pressure. At that time, fluid is forced out of thesecond chamber 82 into thefirst chamber 81. If thearmature 72 moves rapidly enough, the pressure in thesecond chamber 82 reaches a point at which the dampingelement 76 moves sufficiently far to the right where thesecond flute 78 opens a path from the armature bore 74 into thefirst chamber 81. This operation produces a similar damping curve as illustrated inFIG. 3 . Therefore the first control valve exhibits digressive damping in both directions of operation. -
FIG. 4 illustrates a second type of anarmature 90 which has an alternative digressive dampingelement 92. Thisarmature 90 has alongitudinal bore 91 extending between both ends of the armature. One end of thelongitudinal bore 91 has an enlarged opening in which a flat, disk-shaped dampingelement 92 is held by a snap-type retaining ring 93. With additional reference toFIG. 5 , the disk-shaped dampingelement 92 has a U-shaped slot 94 extending there through and centrally located therein. The slot 94 forms a flap 96. When thearmature 90 moves within thesolenoid actuator 60, the pressure differential between thechambers chambers armature 90. This disk-shaped digressive dampingelement 92 functions in a similar manner to the cylindrical dampingelement 76 and itsspring 80 shown inFIG. 1 . -
FIG. 6 illustrates asecond control valve 100 in which components that are the same as those in thefirst control valve 30 have been assigned identical reference numerals. To simplify the description herein, those components will not be described in detail again. Thesecond control valve 100 has a normally high pressure state, meaning that when electric current is not being applied to theelectromagnetic coil 62, thevalve element 102 is biased into a position in which a path is formed between the pressurizedfluid supply port 36 and theworkport 40. As a consequence, thevalve element 102 is slightly different so that theapertures 104 that extend outward from thecentral bore 106 are located to communicate with thesupply port 36 in that de-energized state. Thevalve element 102 directly abuts thearmature 110. - The
armature 110 also is slightly different in that thearmature aperture 114 is located in the midsection of the armature bore 112. The cylindrical digressive dampingelement 116, located in thearmature aperture 114, is biased by a damping spring 118 connected to the side of the damping element that faces thevalve element 102. The damping spring 118 is identical to the previously described dampingspring 80 for thefirst control valve 30 and is secured to the damping element and in the armature bore 112 in the same ways. - An
armature spring 120 biases thearmature 110 away from the exterior end of thesolenoid actuator 60 so as to push the armature and thevalve element 102 into the normally high pressure state of the valve that is illustrated. Aspring adjustment cup 122 is press fitted into an aperture in thefirst pole piece 124 by an amount that sets the force which thearmature spring 120 exerts on thearmature 110. Asecond pole piece 126 provides an interior cylindrical surface against which thearmature 110 slides. - When electric current is applied to the
electromagnetic coil 62 of thesecond control valve 100, a magnetic field is produced within thesolenoid actuator 60 that pulls thearmature 110 father into the electromagnetic coil, i.e., to the left in the orientation of the drawing. This action compresses thearmature spring 120. The bias force applied to thevalve element 102 by theconical coil spring 45 pushes the valve element against the end of thearmature 110 thereby causing the valve element to follow the motion of the armature. Therefore, thevalve element 102 initially moves into a position in which thetransverse apertures 104 are covered by aland 105 within the valve body bore 34. In this position, the fluid communication which previously existed between thesupply port 36 and theworkport 40 is terminated. Thus, fluid is not allowed to flow between those ports. It should be understood that by applying the proper level of electric current to theelectromagnetic coil 62, thevalve element 102 may be maintained in this closed position. Application of a greater level of electric current to theelectromagnetic coil 62 enables thearmature 110 and thevalve element 102 to move farther leftward into a position at which theapertures 104 in the valve element open into theexhaust port 38. Fluid communication now is established between the workport 40 and theexhaust port 38 through the valve element bore 106 and theapertures 104. - As the
armature 110 of thesecond control valve 100 moves, fluid is forced to flow between the first andsecond solenoid chambers armature 110 is moving. For example, when thearmature 110 moves to the left inFIG. 6 , fluid is forced from thesecond chamber 82 into thefirst chamber 81. Initially the fluid flows only around the outside of thearmature 110 and through its bore 112 past the closed digressive dampingelement 116. As the pressure within thesecond solenoid chamber 82 increases due to greater velocity of thearmature 110, the force exerted on the end of the dampingelement 116 that faces thesecond chamber 82 increases. Eventually the force pushes the dampingelement 116 into a position in which thefirst flute 126 provides a path between both sides of thearmature aperture 114. This increases the amount of fluid flow from thesecond chamber 82 into thefirst chamber 81. This operation provides digressive damping of the motion of thearmature 110 and thevalve element 102, as depicted inFIG. 3 . - Thereafter, when the electric current is removed from being applied to the
electromagnetic coil 62, the force of thearmature spring 120 returns thearmature 110 and the abuttingvalve element 102 to the normal position illustrated inFIG. 6 . The pressure differentials produced inchamber element 116 operates in a reverse manner, damping the fluid flow from thefirst chamber 81 into thesecond chamber 82. Therefore the dampingelement 116 provides digressive damping of the bidirectional movement of thearmature 110 andvalve element 102 in thesecond control valve 100. - It should also be appreciated that the disk-type digressive damping
element 92 shown inFIG. 5 could be substituted for the cylindrical dampingelement 116 in thesecond control valve 100. - The foregoing description was primarily directed to one or more embodiments of the invention. Although some attention has been given to various alternatives within the scope of the invention, it is anticipated that one skilled in the art will likely realize additional alternatives that are now apparent from disclosure of embodiments of the invention. Accordingly, the scope of the invention should be determined from the following claims and not limited by the above disclosure.
Claims (19)
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US20180224021A1 (en) * | 2017-02-03 | 2018-08-09 | Svm Schultz Verwaltungs-Gmbh & Co. Kg | Valve and method for manufacturing a valve |
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US20150101674A1 (en) * | 2012-12-20 | 2015-04-16 | Hydril Usa Distribution, Llc | Subsea pressure regulator |
KR101918532B1 (en) * | 2016-12-28 | 2018-11-15 | 주식회사 유니크 | Solenoid valve |
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US698530A (en) * | 1901-06-24 | 1902-04-29 | Frederic H Mason | Automatic valve. |
US2926694A (en) * | 1958-01-02 | 1960-03-01 | Jr William F Macglashan | Air cut-off valve |
FR1409866A (en) * | 1964-07-22 | 1965-09-03 | Citroen Sa Andre | Distributor of a hydraulic braking device of a vehicle |
DE3418761A1 (en) * | 1984-05-19 | 1985-11-21 | Robert Bosch Gmbh, 7000 Stuttgart | INJECTION VALVE |
DE3808962A1 (en) * | 1988-03-17 | 1989-09-28 | Rexroth Mannesmann Gmbh | PRESSURE LIMIT VALVE |
DE4133536C2 (en) * | 1991-10-10 | 1995-11-30 | Hydraulik Ring Gmbh | Hydraulic solenoid valve |
US5205249A (en) | 1992-05-14 | 1993-04-27 | Borg-Warner Automotive Transmission & Engine Components Corporation | Variable camshaft timing system for internal combustion engine utilizing flywheel energy for reduced camshaft torsionals |
US5218935A (en) | 1992-09-03 | 1993-06-15 | Borg-Warner Automotive Transmission & Engine Components Corporation | VCT system having closed loop control employing spool valve actuated by a stepper motor |
US5778932A (en) * | 1997-06-04 | 1998-07-14 | Vickers, Incorporated | Electrohydraulic proportional pressure reducing-relieving valve |
DE19727180C2 (en) * | 1997-06-26 | 2003-12-04 | Hydraulik Ring Gmbh | Hydraulic valve, in particular for controlling a camshaft adjustment in a motor vehicle |
US6179268B1 (en) | 1998-04-21 | 2001-01-30 | Saturn Electronics & Engineering, Inc. | Proportional variable force solenoid control valve with segmented permanent magnet |
DE10037793B4 (en) * | 2000-08-03 | 2007-05-24 | Hydraulik-Ring Gmbh | Solenoid valve, in particular pressure control valve |
US6811135B2 (en) | 2002-10-24 | 2004-11-02 | Eaton Corporation | Solenoid operated sleeve valve |
DE10325177A1 (en) * | 2003-06-04 | 2005-01-05 | Hydac Fluidtechnik Gmbh | Valve |
CN101512201B (en) | 2006-09-26 | 2011-03-09 | 博格华纳公司 | Direct-acting pilot pressure control solenoid |
WO2009010332A1 (en) * | 2007-07-18 | 2009-01-22 | Schaeffler Kg | Valve part for a hydraulic control valve |
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US20180224021A1 (en) * | 2017-02-03 | 2018-08-09 | Svm Schultz Verwaltungs-Gmbh & Co. Kg | Valve and method for manufacturing a valve |
US10851906B2 (en) * | 2017-02-03 | 2020-12-01 | Svm Schultz Verwaltungs-Gmbh & Co. Kg | Valve and method for manufacturing a valve |
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