Axial solenoid valve and armature for an axial solenoid valve

Abstract

Locking anchor (20) for an axial solenoid valve (1) with a rod-shaped body (25) having two end faces (21, 22) and a longitudinal axis (2), wherein - the body (25) has at least one fluid channel (23) which extends in at least one first end section (26) of the body (25) from at least one inlet in a first of the two end faces (21) in the direction of the opposite second end face (21), and - the body (25) has a tapered second end section (29) adjoining the second frontal surface (22), - the lateral surface of the body (25) has at least one first central section (27), and in the first central section (27) there is at least one opening (47) of at least one connecting channel (24) extending obliquely to the longitudinal direction of the longitudinal axis (2), which connects the lateral surface with the fluid channel (23), characterized by the fact that the lateral surface in the first central section (27) in the area of ​​the opening (47) of the connecting channel (24) tapers towards the second end face (22) such that the connecting channel (24) extends at least approximately orthogonally with a tolerance of ±10° to the lateral surface in the area of ​​the opening (47), The lateral surface of the body (25) thickens continuously in a second central section (28) located between the first central section (27) and the second end section (29) in the direction of the first end section (26), the body (25) thickening more slowly in the second central section (28) than the projection of the opening (47) parallel to the longitudinal axis (2) of the connecting channel (24) moves away from the longitudinal axis (2) of the body (25), such that the imaginary extension of the connecting channel (24) along the longitudinal axis (2) of the connecting channel does not intersect the second central section (28), and the lateral surface in the first central section (27) is a spherical layer lateral surface or the negative of a spherical layer lateral surface.

Description

Technical field

[0001] The invention relates to an axial solenoid valve with a closing armature. The closing armature is also referred to as a movable armature and has a rod-shaped body with two end faces and a longitudinal axis, wherein the body has at least one fluid channel which extends in at least a first end section of the body from at least one inlet in one of the two end faces towards the opposite second end face. The second end section adjoining the second end face is preferably tapered. In addition, the body has at least a first central section with at least one opening of at least one connecting channel extending obliquely to the longitudinal direction of the longitudinal axis, which connects the outer surface to the fluid channel. State of the art

[0002] Solenoid valves are classified into two designs: In the first design, the inlet and outlet are arranged on a common longitudinal axis, and the fluid is guided from the inlet through a valve chamber extending perpendicular to this longitudinal axis. The valve chamber has a valve seat that can be closed or opened by a locating armature, which is generally not subject to flow and is movable orthogonally to the longitudinal axis within the valve chamber. The locating armature is driven by a solenoid coil arranged coaxially with it; that is, when the solenoid coil is energized, the locating armature is moved by a magnetic force, typically against a return spring located within the valve chamber.

[0003] The second design is the so-called "inline solenoid valve," also known as "axial solenoid valve." In this design, a closing armature is slidably mounted in a sleeve through which flow is axially present when the valve is open, for example, between a magnetic armature and a valve seat. When the valve is open, the movable armature, also referred to as the closing armature, is subjected to axial flow. The solenoid coil is therefore usually mounted coaxially on the sleeve. Corresponding solenoid valves are described, for example, in EP 1 992 856 A2, DE 10 2006 003 543 A1, and DE 201 15 282 U1. This application deals exclusively with solenoid valves of this second design.

[0004] In the aforementioned, generic patent EP 1 992 856 A2, a normally closed axial solenoid valve is described, comprising a closing armature with a fluid channel extending axially from the inlet side towards the outlet side, from which connecting channels branch off obliquely to the longitudinal axis of the movable armature. These connecting channels open into an annular groove in the outlet-side tapered end section of the movable armature. Similar designs are also shown in DE 35 06 054 A1 and US 2 279 243 A. Description of the invention

[0005] The invention is based on the observation that the annular groove in the tapered outer surface of the movable anchor known from EP 1 992 856 A2, particularly in combination with the obliquely branching connecting channels, The flow resistance of the solenoid valve can be significantly reduced. However, manufacturing the connecting channels is very complex because they have to be milled.

[0006] The invention is based on the objective of providing a solenoid valve that is easier to manufacture, has reduced flow resistance and a shorter response time compared to the solenoid valve known from EP 1 992 856 A2.

[0007] This problem is solved by the locking armature according to claim 1 or by an axial solenoid valve with this locking armature according to claim 4. Advantageous embodiments of the invention are specified in the dependent claims.

[0008] The locking armature has a rod-shaped body with two end faces and a longitudinal axis. The end faces are also referred to as end surfaces. For example, the rod-shaped body can be rotationally symmetrical about its longitudinal axis and, for instance, made from a circular cylinder. In this case, the body is at least substantially cylindrical. Furthermore, the body has at least one first end section with at least one fluid channel extending from one of the two end faces along the longitudinal axis, e.g., centered on the longitudinal axis or parallel to it, towards the opposite second end face. Of course, the fluid channel could also extend slightly obliquely to the longitudinal axis. The lateral surface of the first end section is preferably adapted to the inner diameter of the valve housing to form a sliding bearing that guides the locking armature within the valve housing.The outer surface of the first end section may contain longitudinal grooves that are parallel to the fluid channel in terms of flow direction, in order to further reduce the flow resistance of the valve.

[0009] Typically, the first end face of the closing anchor is located on the inlet side, relative to the preferred flow direction. For the sake of simplicity, the terms "inlet side" and "outlet side" are used hereafter without defining the flow direction through the anchor. Therefore, "inlet side" could be replaced by "facing the first end face" and "outlet side" by "facing away from the first end face."

[0010] As is common with axial solenoid valves, the closing armature preferably has a second end section adjoining the second end face and tapering in this direction, which allows a flow of fluid exiting the armature between the outer surface of the second end section and the valve housing.

[0011] The outer surface of the locking armature according to the invention has at least one first central section, which is arranged between the two end sections. The outer surface of the first central section is connected to the fluid channel by at least one connecting channel extending obliquely to the longitudinal direction of the longitudinal axis. This at least one connecting channel allows flow through the locking armature from the first end face to the tapered second end section and thus provides a connection between the fluid channel and the valve chamber.

[0012] Preferably, the fluid channel transitions into at least one connecting channel, so that no dead space is created in which microbes or particles could accumulate. For example, the fluid channel can be introduced into the body as a blind hole from the first end face, e.g., through a bore. Preferably, the at least one connecting channel branches off from the end of the fluid channel.

[0013] The number of connecting channels can vary as required and depends on the desired Kv value of the valve. Preferably, at least two connecting channels are arranged uniformly around the circumference of the first central section. Distributed outlets are provided. Alternatively, three, four, five, or more connecting channels are also possible. The greater the number of connecting channels, the more evenly the flow is distributed around the second end section, i.e., the... This reduces potential dead spaces and decreases flow resistance. However, beyond a certain number of connecting channels, their achievable diameter decreases, which again increases flow resistance. Furthermore, manufacturing effort increases with the number of connecting channels.

[0014] The cylindrical surface of the first central section tapers towards the second end face in the area of ​​the connecting channel's exit, such that the connecting channel extends at least approximately orthogonally (±10°, preferably ±5° or more precisely) to the cylindrical surface in the area of ​​the opening, i.e., the exit. This allows the connecting channel to be inserted into the locking anchor through a simple, i.e., cost-effective, bore after the central section has been tapered, e.g., by turning. Since the second end section is usually tapered relative to the first end section, the tapering of the central section can be performed in the same operation and, if necessary, with a single tool (e.g., a turning tool) whose contour corresponds to that of the second end section and the first central section, as well as any further sections. Therefore, no additional machining steps are required, and no additional manufacturing costs are incurred.

[0015] In the longitudinal section of the locking anchor, the section of the cylindrical surface into which the bore is inserted is therefore also inclined to the longitudinal axis of the movable anchor. The angle of a recess's longitudinal axis to a typically curved cylindrical surface may seem difficult to determine, but ultimately, the goal is to prevent the drill bit from slipping when it is inserted onto the cylindrical surface of the first central section. Therefore, it suffices if the tangents on the cylindrical surface at the point of insertion of the drill bit are at least approximately orthogonal (±10°, preferably ±5° or more precisely) to the drill's longitudinal axis to minimize the radial forces required to center the drill bit. This angle can also be subsequently determined by a (continuous) continuation of the cylindrical surface, thus at least conceptually closing the opening of the connecting channel.This determination is unambiguous, at least for a central section formed by rotation, due to the continuous rotational symmetry with respect to the longitudinal axis, which is broken by the opening. It suffices to restore the continuous rotational symmetry, at least conceptually. The curve resulting in the longitudinal section of the continuously continued first central section preferably intersects the drill's longitudinal axis at least approximately orthogonally (±10°, preferably ±5° or more precisely). In the case of a curved curve, this naturally means that the drill's longitudinal axis intersects the tangents at the point of contact at least approximately orthogonally (±10°, preferably ±5° or more precisely).

[0016] The lateral surface of the first central section is a spherical layer lateral surface or, preferably, the negative of a spherical layer lateral surface. Here, the drill longitudinal axis is preferably at least approximately orthogonal (±10°, page 4 preferably ±5° or more precisely) to the tangent plane at the intersection of the lateral surface with the drill longitudinal axis.

[0017] As previously indicated, the outer surface of the first central section particularly preferably defines an annular recess in the body's outer surface. This allows the mass of the movable armature to be significantly reduced, which increases the response time of the solenoid valve. This means that the body thickens continuously in the direction of the first end section in a second central section, which is located between the first central section and the second end section.

[0018] In this process, the body thickens more slowly in the second central section, or at the same rate as the projection of the connecting channel opening, parallel to the connecting channel's longitudinal axis, moves away from the body's longitudinal axis. This keeps the connecting channel extension unobstructed, which facilitates its insertion and improves flow to and from the connecting channel, thus reducing flow resistance. A further effect is a further improvement in the solenoid valve's response time, as the mass of the moving armature is further reduced. Additionally, the service life of an elastic sealing element, typically located on or within the second end face, is increased. This sealing element absorbs the acceleration forces that must be counteracted when the valve closes, as the closing armature comes into contact with the valve seat.As the mass decreases, the acceleration forces and thus the stress on the sealing element are reduced. The sealing element can, for example, sit in a recess on its end face; this recess may be undercut so that the resulting radially inward-facing edge securely holds the sealing element. The edge is preferably chamfered on the end face to facilitate insertion of the sealing element.

[0019] Preferably, the sealing element has at least one hole connecting its two end faces. This improves the sealing effect and eliminates the need for a pressure equalization channel, which is necessary according to the prior art.

[0020] These pressure equalization channels represent a dead space that is not flushed during operation of the solenoid valve, which leads to problems particularly when the valve is used to dispense foods such as milk or sugary drinks, as germs can accumulate in these areas.

[0021] The solenoid valve according to the invention preferably has a sleeve-shaped valve housing with an outlet and a valve seat surrounding a valve opening. The previously described movable armature is axially displaceable within the sleeve-shaped valve housing between the valve seat and a magnetic armature and is preferably biased in one direction, e.g., by a spring element. The magnetic armature can be connected to the housing or be contained within the valve housing. Preferably, the magnetic armature connects the valve housing to the fluid inlet via at least one fluid channel. A magnetic coil is preferably mounted on the sleeve-shaped valve housing. The closing armature can, for example, be made of a magnetically conductive material so that it is displaced towards the magnetic armature when the magnetic coil is energized.The spring element and / or the flow cause the closing armature to return towards the valve seat when the solenoid coil is switched off. Alternatively, the valve seat can be located on the solenoid armature; in this case, unlike the previously described normally closed version, the valve would be normally open, and the closing armature would be biased in the opposite direction. Furthermore, the preferred flow direction reverses; that is, the port previously designated as the inlet becomes the outlet, and vice versa.

[0022] To avoid any misunderstandings, the terms "tapering" and "thickening" are explained again below. A taper is a reduction in the circumference U(x) of a rod-like body as a function of its axial position x. That is, if U(x1) < U(x2) ∀ x1 < x2, then the body tapers in the region of all x1, x2 in the direction of x1. Conversely, the body thickens from x1 towards x2. Preferably, for rotationally symmetric rods, tapering or thickening refers to a reduction or increase in the radius r, respectively. In this case, r(x1) < r(x2) ∀ x1 < x2 describes a taper between x4 and x2 in the direction of x1, or a thickening between x1 and x2 in the direction of x2. Tapering, thickening, or widening can refer to the outer circumference (or radius) as well as to the circumference (or radius) of cavities. Description of the drawings

[0023] The invention is described below by way of example, without limiting the general concept of the invention, with reference to the drawings. Fig. Figure 1 shows a schematic structure of a solenoid valve according to the invention. Fig. Figure 2 shows an isometric view of the locking anchor. Fig. 1. Fig. Figure 3 shows a side view of the locking anchor. Fig. 1. Fig. 4 shows the locking anchor Fig. 1 in longitudinal section UU (see Fig. 3). Fig. 5 shows detail V from Fig. 4 and Fig. 6 shows the locking anchor Fig. 1 in cross-section TT (see Fig. 3)

[0024] In Fig. Figure 1 shows an example of an axial solenoid valve 1 in longitudinal section. The solenoid valve 1 has a sleeve-shaped valve housing 10 with a longitudinal axis 2 and a port a, which, in the preferred flow direction 3, is the valve outlet. The valve housing 10 contains a valve chamber with an annular valve seat 11 surrounding a valve opening 12. A fixed magnetic armature 30 with an axial fluid passage 32 is connected to the valve housing 10 on the inlet side. The fluid passage 32 is an opening that connects a port b, connected to the fixed armature, to the valve chamber. A solenoid coil 8 is mounted coaxially on the valve housing 10 and the magnetic armature 30 and is fixed to the valve housing 10 by a thickened section on the outlet side of the valve housing 10 and the port b, both of which act as axial stops.In the valve chamber of the valve housing 10, an axially displaceable closing armature 20 is arranged, which is pressed against the valve seat 11 by a spring element 5 supported on the magnetic armature 30, thus closing the valve opening 12. When the magnetic coil 8 is energized, the closing armature 20 is drawn against the force of the spring element 5 into the magnetic coil 8, i.e., in the direction of the magnetic armature 30, and releases the valve seat 11 and thus the valve opening 12. On the exhaust side, the closing armature 20 has a recess 221 on its end face (see figure 1). Fig. 4 and Fig. 5), in which a preferably rubber-elastic sealing element 6 is seated, which seals the valve seat 11 and thus the valve opening 12 when the solenoid coil 8 is switched off. Preferably, the sealing element 6 has at least one hole 7 connecting its two end faces. This improves the sealing effect and eliminates the need for a pressure equalization channel required according to the prior art. As shown by way of example, the end-face recess 221 can be undercut, i.e., preferably widen in a stepped manner towards the first end face, so that a radially inwardly projecting edge 222 formed thereby overlaps the sealing element 6 and thus securely fixes, i.e., holds it in place. The end face of the edge 222 is preferably chamfered as shown to facilitate the insertion of the sealing element.

[0025] In the Fig. 2 to Fig. Figure 5 shows the locking anchor 20 in detail. The locking anchor 20 is rod-shaped, i.e., it has a longitudinal axis 2 and a first end face 21 and an opposing second end face 22 (see Figure 5). Fig. 2 to Fig. 4).

[0026] As in Fig. 2 and Fig. As can be clearly seen in Figure 3, a first end section 26 of the lateral surface of the locking armature 20 adjoins the first end face 21. In the example shown, this end section 26 corresponds to the lateral surface of a circular cylinder, which is particularly easy to machine by turning. Alternatively, other shapes are of course possible, e.g., cylindrical lateral surfaces with different guide curves such as prismatic lateral surfaces (see Bronstein, Semedjajev, Taschenbuch der Mathematik, Verlag Harry Deutsch, Frankfurt a. M., 1993, Chapter 3.1.2.4). In addition, the lateral surface could also have recesses for bearing rings and / or longitudinally extending grooves to reduce the flow resistance of the solenoid valve.

[0027] On the outlet side, i.e. in the direction of the second end face 22, the surface of the mantle tapers continuously in a first central section 27 (cf. Fig. 2 to Fig. 5) In the example shown, this first central section 27 has the lateral surface of a truncated cone, but other shapes are also possible, in particular the shape of a spherical layer lateral surface or the shape of the negative of a spherical layer lateral surface. An optional second central section 28 adjoins this first central section 26 on the outlet side, in which the lateral surface thickens continuously. This second central section 28 can also, for example, have the shape of a truncated cone.

[0028] The second central section 28 of the lateral surface is adjoined by a second end section 29, which preferably transitions in a rounded manner into the second end surface 22 (cf. Fig. 3 to Fig. 5) In the second end face 22, a recess 221 can be arranged as a receptacle for a sealing element, as shown by way of example. In this example, the receptacle is a counter-turned blind hole 221 (cf. Fig. 4 and Fig. 5).

[0029] The transitions between sections 26, 27, 28 and 29 are preferably rounded to prevent dead spaces or turbulence when flow passes through the solenoid valve 1.

[0030] From the first end face 21, a stepped, tapered blind hole 23 is introduced into the body 25 of the locking anchor 20 as a fluid channel. The step in the fluid channel 23 can be, as in Fig. 1 is shown to serve as a support for a spring element 5.

[0031] From the end of the fluid channel 23, four connecting channels 24 extend as an example of at least one, which are inclined to the longitudinal axis 2 (in the example shown, four connecting channels are realized, cf. Fig. 6; of course, other numbers can also be realized in the same way, i.e., at least one, preferably two or more, preferably evenly distributed around the circumference, connecting channels. Each of the connecting channels 24 has a longitudinal axis 42 and an opening 47 in the first central section 27 of the lateral surface (cf. Fig. 5 and Fig. 6) Consequently, the connecting channels 24 connect the fluid channel 23 to the cylindrical surface of the second end section 29 and thus to the valve chamber. The longitudinal axes 42 of the connecting channels 24 are also referred to as drill longitudinal axes 42 for linguistic distinction from the longitudinal axis 2, since the connecting channels 24 can be very easily introduced into the body 25 by drilling, because the tapering of the first central section 27 is designed such that a surface orthogonal to the drill longitudinal axis is formed. Therefore, no radial forces acting on the drill due to an inclination of the drill relative to the cylindrical surface would need to be absorbed or could even lead to breakage of the drill, at least if the tapering is first screwed into the cylindrical surface and then the connecting channel is drilled. The longitudinal section (cf. Fig. 5) The curve resulting from the first central section 27 intersects the longitudinal axis of the drill orthogonally (±10°, preferably ±5° or more accurately).

[0032] The second central section 28 also facilitates the drilling of the connection holes 24 and simultaneously improves the flow characteristics of the solenoid valve 1, because the flow can exit the openings 47 unimpeded, i.e., without deflection. The longitudinal section (cf. Fig. 5) The curve resulting from the second middle section 28 (“section curve”) is orthogonal in the example shown to the curve in the longitudinal section (cf. Fig. 5) the curve resulting from the first central section 27. The angle can also be larger, but should not be significantly smaller so that the imaginary extension of the connecting channel 24 along the longitudinal axis 42 of the drill is not projected onto the second central section 28. In other words, the lower limit angle is preferably determined such that a projection of the opening 47 of the connecting channel 24 parallel to the longitudinal axis 42 of the drill does not fall onto the second central section 28. This projection is in Fig. 5 indicated by lines 48, which in the example shown run parallel to the second middle section.

[0033] If the radius of the lateral surface in the region of the second end section 29 is less than or equal to the minimum radius of the first central section 27, then the second central section 28 can be omitted. This allows the locking armature to be made even lighter. The minimum radius of the second end section 29 is essentially determined by the diameter of the valve opening 12 or the valve seat 11. Reference symbol list 1 solenoid valve 2 Longitudinal axis 3 Preferred flow direction 5 spring element 6 Sealing element 7 holes 8 Magnetic coil 10 Valve housings 11 Valve seat 12 Valve opening 20 locking anchors 21 first front face / first front surface 22 second front face / first front face 23 Fluid channel / blind hole 24 connection channels 25 bodies 26 first end section of the lateral surface 27 first central section of the lateral surface 28 second central section of the lateral surface 29 second end section of the lateral surface 30 magnetic armatures 32 Fluid opening 42 Longitudinal axis of a connecting channel 24 / drill longitudinal axis 47 Opening of a connecting channel 48 projection lines 221 Frontal recess 222 radially inward-pointing edge of the recess 221 a connection / outlet b Connection / Inlet

Claims

[1] Locking armature (20) for an axial solenoid valve (1) with a rod-shaped body (25) having two end faces (21, 22) and a longitudinal axis (2), wherein - the body (25) has at least one fluid channel (23) which extends in at least one first end section (26) of the body (25) from at least one inlet in a first of the two end faces (21) in the direction of the opposite second end face (21), and - the body (25) has a tapered second end section (29) adjoining the second frontal surface (22), - the lateral surface of the body (25) has at least one first central section (27), and in the first central section (27) there is at least one opening (47) of at least one connecting channel (24) extending obliquely to the longitudinal direction of the longitudinal axis (2), which connects the lateral surface with the fluid channel (23), characterized by , that the lateral surface in the first central section (27) in the area of ​​the opening (47) of the connecting channel (24) tapers towards the second end face (22) such that the connecting channel (24) extends at least approximately orthogonally with a tolerance of ±10° to the lateral surface in the area of ​​the opening (47), The lateral surface of the body (25) thickens continuously in a second central section (28) located between the first central section (27) and the second end section (29) in the direction of the first end section (26), the body (25) thickening more slowly in the second central section (28) than the projection of the opening (47) parallel to the longitudinal axis (2) of the connecting channel (24) moves away from the longitudinal axis (2) of the body (25), such that the imaginary extension of the connecting channel (24) along the longitudinal axis (2) of the connecting channel does not intersect the second central section (28), and the lateral surface in the first central section (27) is a spherical layer lateral surface or the negative of a spherical layer lateral surface. [2] Locking anchor (20) according to claim 1, characterized by , that the lateral surface in the first central section (27) defines an annular recess in the lateral surface of the body (25) in the axial direction. [3] Locking anchor (20) according to one of the preceding claims, characterized by , that a recess (221) is arranged on or in the second end face (22) as a receiving for a sealing element (6) for sealing a valve seat (11). [4] Axial solenoid valve (1) with a closing armature (20), characterized by , that the locking anchor (20) is a locking anchor (20) according to one of the preceding claims.

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