Valve armature for a solenoid valve and valve cartridge for a solenoid valve

Abstract

Valve armature (10) for a solenoid valve, comprising a base body (11) and a plunger (20) cooperating with a valve seat, wherein a damping device (24) is arranged between the plunger (20) and the base body (11), which has a cavity (24.2) fillable with a damping medium (24.6) and a throttle opening (24.4) through which the damping medium (24.6) flows out of or into the cavity (24.2), wherein the plunger (20) has a recess (21.2) at an end region (21) facing the base body (11) and the base body (11) has an end wall (11.4) at an end region (11.2) facing the plunger (20), wherein the damping device (24) provides a damping force when the plunger (20) strikes the dampens the impulse arising in the valve seat, wherein the end wall (11.4) and the recess (21.2) form the cavity (24.2) of the damping device (24), wherein the defined cavity (24.2) between plunger (20) and base body (11) the stiffness of a mechanical interface between plunger (20) and base body (11) is deliberately weakened and thus acts as a spring element.

Description

[0001] The invention relates to a valve armature for a solenoid valve and an associated valve cartridge for a solenoid valve.

[0002] Normally open or closed solenoid valves are known from the prior art and are used, for example, as inlet or outlet valves in a hydraulic unit of a vehicle braking system. The hydraulic unit can be used to control and / or regulate pressure build-up and pressure release in corresponding wheel brake calipers within an anti-lock braking system (ABS), an anti-slip regulation system (ASR), or an electronic stability program (ESP). Such solenoid valves comprise a solenoid assembly and a valve cartridge. The valve cartridge includes a pole piece, a guide sleeve connected to the pole piece, and a valve armature that is axially movable within the guide sleeve against the force of a return spring between a closed and an open position. The valve armature can have a base body and a plunger.In the closed position, the plunger acts as a seal against a valve seat, interrupting fluid flow between at least one first and at least one second flow port. In the open position, the plunger is lifted from the valve seat, allowing fluid flow between the first and second flow ports. Energizing the solenoid assembly generates a magnetic force that moves the plunger body from the open position to the closed position when the solenoid valve is de-energized, until the plunger contacts the corresponding valve seat and seals it. When de-energized, the return spring moves the plunger body, lifting it from the valve seat and releasing it.In a solenoid valve that is closed when de-energized, the plunger body is moved from the closed position to the open position by the energizing of the solenoid assembly. The plunger then lifts out of the valve seat, releasing it. When the current is switched off, the return spring moves the plunger body towards the valve seat until the plunger engages and seals it. The solenoid valves described above produce a so-called closing noise when the plunger, which includes a closing element (for example, a steel ball and / or a dome), strikes the valve seat, which is made of, for example, hardened steel.

[0003] German patent application DE 10 2007 051 557 A1 describes, for example, a normally closed solenoid valve for a slip-controlled hydraulic vehicle braking system. The solenoid valve comprises a hydraulic part, also referred to as a valve cartridge, which is partially arranged in a stepped bore of a valve block, and an electrical part, which essentially consists of a magnetic assembly mounted on the portion of the valve cartridge protruding from the valve block. The magnetic assembly comprises a coil former with an electrical winding, a magnetic flux-conducting coil sheath, and a magnetic flux-conducting annular disc. The hydraulic part has a guide sleeve, the end of which facing the electrical part is sealed with a pressed-in and fluid-tight welded pole piece.The guide sleeve houses a longitudinally displaceable armature, which is supported on the pole core by a return spring. On the end opposite the pole core, the armature has a spherical closing element arranged in a recess. At the end opposite the pole core, a cup-shaped valve sleeve with a cylindrical shell and a base is pressed into the guide sleeve. The valve sleeve has a passage at its base and a hollow, conical valve seat, which, together with the closing element, forms a poppet valve. The poppet valve allows for a switchable fluid connection between the passage at the base of the valve sleeve and at least one passage in the shell of the valve sleeve. Additionally, a radial filter is arranged on the outside of the shell of the valve sleeve to filter dirt particles from the fluid flow. The guide sleeve can be secured in the stepped bore of the valve block using a mounting bushing.

[0004] From DE 10 2011 089 288 A1, a flow control valve, in particular for metering a fluid to a downstream high-pressure pump, is known, comprising an axially movable valve needle and a valve element acted upon by the valve needle in an opening direction. The valve element defines a damping chamber. An annular gap with at least one bulge is present between a wall of the damping chamber and the valve element.

[0005] From US Patent 2007 / 0069166A1, a solenoid valve is known which comprises an inlet, an outlet, a valve seat in the flow path between the inlet and the outlet, a stationary core, and a movable element for movement between an open position and a closed position against the valve seat. An elastic damping element is arranged between the movable element and the stationary core and is independent of both the stationary core and the movable element. A spring biases the elastic damping element against the stationary core and biases the movable element away from the stationary core into a closed position. A magnet can be energized by applying a DC voltage or a rectified AC current to move the movable element from the closed position toward the stationary element into an open position against the elastic damping element.Accordingly, the solenoid valve has an elastic damping element that dampens the impact between the moving element and the stationary core in order to reduce the noise associated with the activation of the magnet. Disclosure of the invention

[0006] The valve armature according to the invention for a solenoid valve with the features of independent claim 1 and the corresponding valve cartridge for a solenoid valve with the features of independent claim 8 have the advantage that, by modifying the valve armature, which comprises a base body and a plunger, the closing noise occurring during closing can be reduced and, in the optimal case, even almost completely eliminated. By using a damping device, which is arranged between the plunger and the base body and has a cavity that can be filled with a damping medium and a throttle opening through which the damping medium flows out of or into the cavity, the impulse when the plunger strikes the valve seat can be dampened, so that structure-borne noise in the system can be advantageously reduced.The closing noise that occurs during closing can also be reduced by a delayed deceleration of the moving mass of the plunger, by allowing the damping medium to flow out of the cavity when the plunger acts on the cavity.

[0007] Thus, embodiments of the present invention contribute to improving the NVH (Noise, Vibration, Harshness) behavior of the vehicle by reducing and ideally completely eliminating the disturbing noises generated when the solenoid valve closes. This makes it possible to design the vehicle's braking system as a single-box system and to bolt the hydraulic unit directly to the vehicle's firewall, since no disturbing closing noises can enter the passenger compartment.

[0008] Embodiments of the present invention provide a valve armature for a solenoid valve, comprising a base body and a plunger that interacts with a valve seat. A damping device is arranged between the plunger and the base body, the damping device having a cavity fillable with a damping medium and a throttle opening through which the damping medium flows out of or into the cavity, the damping device damping an impulse generated when the plunger strikes the valve seat. The plunger has a recess at an end region facing the base body, and the base body has an end wall at an end region facing the plunger, the end wall and the recess forming the cavity of the damping device.In this design, the defined cavity between the tappet and the base body intentionally reduces the stiffness of the mechanical interface between them, allowing it to act as a spring element. In the closed state, the end wall of the base body rests against the edge of the recess. This reduced stiffness and the predetermined damping characteristics of the interface advantageously result in further noise reduction. Furthermore, the cavity can be easily created by the recess in the tappet and by connecting the tappet to the base body. This effectively prevents the tappet from jumping when it impacts the valve seat, as the damping characteristics of the mechanical interface can be controlled by the tappet wall thickness and the dimensions of the throttle opening.Furthermore, the braking effect of the damping device not only reduces noise but also prevents damage to the tappet at the end facing the valve seat. The tappet can have a closing element at this end, preferably in the form of a spherical cap. In the closed position, the closing element seals against the valve seat.

[0009] Furthermore, a valve cartridge for a solenoid valve is proposed, comprising a pole core, a guide sleeve connected to the pole core, a valve armature according to the invention which is axially movable within the guide sleeve against the force of a return spring between a closed position and an open position and which has a base body and a plunger, and a valve sleeve connected to the guide sleeve with a valve seat which is arranged between at least one first flow opening and at least one second flow opening. In the closed position, the plunger acts as a seal against the valve seat and interrupts fluid flow between the at least one first flow opening and the at least one second flow opening. In the open position, the plunger is lifted from the valve seat and allows fluid flow between the at least one first flow opening and the at least one second flow opening.

[0010] The measures and further developments listed in the dependent claims enable advantageous improvements to the valve armature for a solenoid valve specified in independent claim 1 and the valve cartridge for a solenoid valve specified in independent claim 8.

[0011] A particular advantage is that the damping behavior of the damping device can be influenced by the dimensions of the throttle opening. For example, pressure exerted by the plunger can be compensated for more quickly through a large throttle opening than through a comparatively smaller one, since the larger opening allows the damping medium to flow out of the cavity more rapidly. This advantageously enables simple and cost-effective manufacturing of the damping device, whose damping behavior can be easily adapted to the model of the solenoid valve or the valve cartridge.

[0012] In a further advantageous embodiment of the valve armature according to the invention, the throttle opening can be designed as a groove. A groove can advantageously be easily formed in a wall of the cavity, for example in the inner wall of the plunger.

[0013] In a further advantageous embodiment of the valve armature according to the invention, the base body can comprise a magnetizable material. The magnetizable material allows the base body to be attracted to or repelled by the pole core. The magnetic force allows the base body to be moved against a spring force between the open and closed positions, or between the closed and open positions. The base body can, for example, be made of iron. Furthermore, the base body can be manufactured as a sintered component.

[0014] In a further advantageous embodiment of the valve armature according to the invention, the plunger can be manufactured as a plastic injection-molded part. Plungers with different dimensions and recesses can be easily produced by injection molding. Furthermore, plastic injection-molded parts made of, for example, thermoplastics can be manufactured cost-effectively. In addition, a plunger manufactured as a plastic injection-molded part generates less noise when it strikes the valve seat compared to a metallic plunger.

[0015] In a further advantageous embodiment of the valve armature according to the invention, the plunger and the base body can be connected to each other via a press fit. Here, the plunger, at its end region facing the base body, can rest on a bearing surface of the base body facing the plunger, with the areas surrounding the projection. The cavity between the plunger and the base body is created by the recess in the plunger. The throttle opening is then formed in a wall of the recess in the plunger.

[0016] In a further advantageous embodiment of the valve armature according to the invention, an inner wall of the plunger in the area of ​​the press fit can have a contour through which the damping medium can flow into or out of the cavity via the throttle opening. Furthermore, the contour can advantageously compensate for different coefficients of thermal expansion of the different materials. In addition, the base body can have a groove or a recess which, in the connection area between the base body and the plunger, allows the damping medium to flow into or out of the cavity.

[0017] In an advantageous embodiment of the valve cartridge, the fluid flowing between the first and second flow openings in the open position can flow into the cavity between the base body and the plunger, forming the damping medium. Advantageously, the damping medium is already present and can flow into or out of the cavity via an inlet or outlet formed by the contour of the plunger and the groove of the base body.

[0018] An embodiment of the invention is shown in the drawing and is explained in more detail in the following description. In the drawing, identical reference numerals denote components or elements that perform the same or analogous functions. Brief description of the drawings Fig. Figure 1 shows a schematic longitudinal section view of an embodiment of a valve armature according to the invention for a solenoid valve. Fig. Figure 2 shows a schematic top view of the valve armature made of Fig. 1. Fig. Figure 3 shows a schematic longitudinal section of an embodiment of a valve armature plunger made of Fig. 1 and Fig. 2. Fig. Figure 4 shows a schematic top view of the plunger made of Fig. 3. Embodiments of the invention

[0019] A valve cartridge (not shown) for a solenoid valve comprises a pole core, a guide sleeve connected to the pole core, and a valve armature 10 guided axially within the guide sleeve against the force of a return spring between a closed position and an open position. The valve armature 10 comprises, as shown in Fig. 1 and Fig. Figure 2 shows a base body 11 and a plunger 20, wherein a valve seat is arranged between at least one first flow opening and at least one second flow opening. In the closed position, the plunger 20 acts as a seal against the valve seat and interrupts fluid flow between the at least one first flow opening and the at least one second flow opening. In the open position, the plunger 20 is lifted from the valve seat and allows fluid flow between the at least one first flow opening and the at least one second flow opening.

[0020] As from Fig. 1 and Fig. As can be seen in Figure 2, the valve armature 10 for a solenoid valve in the illustrated embodiment comprises the base body 11 and the plunger 20 which interacts with the valve seat. A damping device 24 is arranged between the plunger 20 and the base body 11, which has a cavity 24.2 that can be filled with a damping medium and a throttle opening 24.4 through which the damping medium 24.6 flows out of or into the cavity 24.2, the damping device 24 damping an impulse generated when the plunger 20 strikes the valve seat.

[0021] As from Fig. 1 and Fig. As can be seen further in Figure 2, the valve armature 10 in the illustrated embodiment is designed in two parts. The base body 11 is made of a magnetizable material. In the illustrated embodiment, the base body 11 is designed as a sintered iron component. The base body 11 has a cavity 11.8 in which a return spring (not shown) can be guided. Alternatively, the base body 11 can also be made of a different magnetizable material. Furthermore, the base body 11 can also be cold-forged to achieve a predetermined shape. When a magnetic assembly is energized, a magnetic force is generated which moves the sintered iron base body 11 from the open position to the closed position when the solenoid valve is not energized. The plunger 20, connected to the base body 11, then strikes the corresponding valve seat and seals it.In the de-energized state, the return spring moves the base body 11 with the plunger 20 back to its initial position, and the plunger 20 lifts off the valve seat, releasing it. When the solenoid valve is closed (de-energized), the base body 11 with the plunger 20 is moved from the closed position to the open position by energizing the solenoid assembly, and the plunger 20 lifts off the valve seat, releasing it. When the current is switched off, the return spring moves the base body 11 with the plunger 20 back towards the valve seat, pressing the plunger 20 into the valve seat and sealing it. In the illustrated embodiment, the plunger 20 is manufactured as an injection-molded thermoplastic part. Other suitable materials can also be used to manufacture the plunger 20. A closing element 22.2 is arranged at an end region 22 of the plunger 20 facing the valve seat and away from the base body 11.In the illustrated embodiment, the closing element 22.2 is designed as a spherical cap and integrally formed with the cylindrical plunger 20. Of course, other suitable geometric shapes can also be used for the closing element 22.2 and the plunger 20. For example, the plunger 20 can also be designed as a cuboid or cube, and the closing element 22.2 can, for example, be designed as a cone or a truncated cone. To achieve an additional damping effect, the closing element 22.2 can be manufactured as an injection-molded plastic part, such as a PEEK part. The plunger 20 has a smaller outer diameter at the end region 22 facing the valve seat and away from the base body 11 than at an end region 21 facing the base body 11. The plunger 20 and the base body 11 are connected to each other at their opposing end regions 21 and 11.2 by means of an interference fit 12.In this configuration, an end wall 21.4 of the plunger 20, facing the base body 11, rests against an end wall 11.4 of the base body 11, also facing the plunger 20. Furthermore, an inner wall 26 of the plunger 20 rests against an outer wall 11.1 of the base body 11. In the illustrated embodiment, the plunger 20 is mounted on the base body 11 and pressed into it. When the closing element 22.2 strikes the valve seat, the impulse is transmitted to the plunger 20. The impulse is then essentially transmitted to the damping device 24 located between the plunger 20 and the base body 11. Here, the damping medium 24.6 flows through the throttle opening 24.4 from the cavity 24.2, thereby delaying the movement of the plunger 20 and essentially preventing impulse transmission to the base body 11. This reduces or even completely eliminates the resulting closing noises. In the open position, the damping medium 24.6 flow into the cavity 24.2 via the throttle opening 24.4. The damping behavior of the damping device 24 can be influenced by the dimensions of the throttle opening 24.4.

[0022] As from Fig. As can be seen in Figures 1 to 4, the throttle opening 24.4 in the illustrated embodiment is formed as a U-shaped groove in the inner wall 26 of the plunger 20. In an alternative embodiment, the throttle opening 24.4 can also be rectangular. Furthermore, the damping device 24 in the illustrated embodiment has only one throttle opening 24.4. In an alternative embodiment, the damping device 24 can have several throttle openings 24.4.

[0023] As from Fig. As can be seen further in Figures 1 to 4, the plunger 20 has a recess 21.2 at its end region 21 facing the base body 11. The end wall 11.4 of the end region 11.2 of the base body 11 facing the plunger 20 forms the cavity 24.2 of the damping device 24 with the recess 21.2, the end wall 11.4 of the base body resting on the edge of the recess 21.2 when closed. The cavity 24.2 between the plunger 20 and the base body 11 selectively weakens the stiffness of the mechanical interface between the plunger 20 and the base body 11 and forms a spring element. The spring properties depend on the filling with damping medium 24.6 and on the wall thickness of the surrounding walls 11.4, 21.3. In this case, the throttle opening 24.4 and the surrounding walls 11.4, 21.3 have dimensions which prevent damage to the plunger 20 from increasing pressure when closing the solenoid valve in the area of ​​the damping device 24.

[0024] As from Fig.As can be seen in Figures 1 to 4, the inner wall 26 of the plunger 20 has a contour 26.2 in the area of ​​the press fit 12, through which the damping medium 24.6 can flow into or out of the cavity 24.2. The contour 26.2 forms contact surfaces 26.3, which bear against and are connected to the outer wall 11.1 of the base body 11. Furthermore, the contour 26.2 forms passage channels 26.4, through which the damping medium 24.6 can flow between the base body 11 and the plunger 20 from the outside to the throttle opening 24.4 and into the cavity 24.2, or from the cavity 24.2 and the throttle opening 24.4 to the outside. In addition to forming passage channels 26.4, the contour 26.2 on the inner wall of the plunger 26 can compensate for different coefficients of thermal expansion of the different materials. Furthermore, settling of the plunger 20 can be largely prevented.The base body 11 includes an inlet 11.6, which is designed as a groove on the outer wall 11.1. The damping medium 24.6 can flow from the outside into the passage channel 26.4 of the plunger 20 via the inlet 11.6 or flow out of the passage channel 26.4. The outer wall 11.1 of the base body 11 can be aligned with an outer wall 28 of the plunger 20 in the area of ​​the press fit 12.

[0025] In the valve cartridge not shown, the fluid flowing in the open position between the first flow opening and the second flow opening can flow into the cavity 24.2 between the base body 11 and the plunger 20 and form the damping medium 24.6 to dampen the closing noise.

[0026] Embodiments of the present invention provide a valve armature and a valve cartridge for a solenoid valve, which, by employing a damping device between the plunger and the base body, advantageously dampen the impulse when the plunger strikes the valve seat with a closing element, thus reducing structure-borne noise in the vehicle. The damping device comprises a cavity fillable with a damping medium and a throttle opening.

Claims

[1] Valve armature (10) for a solenoid valve, comprising a base body (11) and a plunger (20) cooperating with a valve seat, wherein a damping device (24) is arranged between the plunger (20) and the base body (11), which has a cavity (24.2) fillable with a damping medium (24.6) and a throttle opening (24.4) through which the damping medium (24.6) flows out of or into the cavity (24.2), wherein the plunger (20) has a recess (21.2) at an end region (21) facing the base body (11) and the base body (11) has an end wall (11.4) at an end region (11.2) facing the plunger (20), wherein the damping device (24) provides a damping force when the plunger (20) strikes the recess (21.2) dampens the impulse arising on the valve seat, wherein the end wall (11.4) and the recess (21.2) form the cavity (24.2) of the damping device (24), wherein the defined cavity (24.2) between plunger (20) and base body (11) the stiffness of a mechanical interface between plunger (20) and base body (11) is deliberately weakened and thus acts as a spring element. [2] Valve armature according to claim 1, characterized by , that the damping behavior of the damping device (24) can be influenced by the dimensions of the throttle opening (24.4). [3] Valve armature according to claim 1 or 2, characterized by , that the throttle opening (24.4) is designed as a groove. [4] Valve armature according to any one of claims 1 to 3, characterized by , that the base body (11) has a magnetizable material. [5] Valve armature according to any one of claims 1 to 4, characterized by , that the plunger (20) is designed as a plastic injection molded part. [6] Valve armature according to any one of claims 1 to 5, characterized by , that the plunger (20) and the base body (11) are connected to each other via a press fit (12). [7] Valve anchor according to claim 6, characterized by , that an inner wall (26) of the plunger (20) in the area of ​​the press fit (12) has a contour (26.2) through which the damping medium (24.6) can flow into the cavity (24.2) or out of the cavity (24.2). [8] Valve cartridge for a solenoid valve comprising a pole core, a guide sleeve connected to the pole core, a valve armature (10) axially movably guided within the guide sleeve against the force of a return spring between a closed position and an open position, the armature comprising a base body (11) and a plunger (20), wherein a valve seat is arranged between at least one first flow opening and at least one second flow opening, wherein the plunger (20) in the closed position seals against the valve seat and interrupts fluid flow between the at least one first flow opening and the at least one second flow opening, and wherein the plunger (20) in the open position is lifted from the valve seat and allows fluid flow between the at least one first flow opening and the at least one second flow opening, characterized by, that the valve armature (10) is designed according to one of claims 1 to 7. [9] Valve cartridge according to claim 8, characterized by , that the fluid which flows in the open position between the first flow opening and the second flow opening flows into the cavity (24.2) between the base body (11) and the plunger (20) and forms the damping medium (24.6).

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