EP4623232A1

EP4623232A1 - Solenoid valve and vehicle, in particular utility vehicle

Info

Publication number: EP4623232A1
Application number: EP22822318.6A
Authority: EP
Inventors: Rafal Bialon
Original assignee: ZF CV Systems Europe BV
Current assignee: ZF CV Systems Europe BV
Priority date: 2022-11-23
Filing date: 2022-11-23
Publication date: 2025-10-01
Also published as: WO2024110030A1; CN120129796A

Abstract

Solenoid valve (1) for pneumatic applications for a vehicle (100a), in particular utility vehicle (100b), wherein said fluid valve (1) comprises: an inner valve core (16) extending along a longitudinal axis (A), valve plate (8) displaceable between a basic position (BP) and an activated position (AP), for closing and opening at least one valve seat (4), an outer yoke (15), a valve connection body (2) with an inlet channel (3) extending along the longitudinal axis (A), a spring (26) for biasing said valve plate (8) into its basic position, and an electromagnetic coil (20) to be energized for creating a magnetic circuit (42) flowing through said inner valve core (16), said outer yoke (15) and said valve plate (8), for switching the valve plate (8) into said activated position, wherein the valve inlet channel (3) comprises at least three guiding ribs (38) arranged around or at an outer cylindrical surface (39) of the valve inlet channel (3) and being distributed along a circumference (39a) of the valve inlet channel (3), wherein the at least three guiding ribs (38) and an inner guiding contour (31a) of an annular protrusion (31) of the valve plate (8) are adapted to enable a vertical alignment of the valve plate (8) with respect to the valve inlet channel (3) when a linear displacement of the valve plate (8) occurs due to an energization of the electromagnetic coil (20).

Description

Solenoid valve and vehicle, in particular utility vehicle

The present invention relates to a solenoid valve for pneumatic applications for a vehicle, in particular a utility vehicle, wherein said fluid valve comprises: an inner valve core extending along a longitudinal axis, a valve plate displaceable between a basic position and an activated position, for closing and opening at least one valve seat, an outer yoke, a valve connection body with an inlet channel extending along the longitudinal axis, a spring for biasing said valve plate into its basic position, and an electromagnetic coil to be energized for creating a magnetic circuit flowing through said inner valve core, said outer yoke and said valve plate, for switching the valve plate into said activated position. The present invention also relates to a vehicle, in particular utility vehicle, comprising such a solenoid valve.

In a solenoid valve, an armature, such as the valve plate, is biased by a spring thereby defining a basic position or basic state, which can be the closed or the open state of the valve, i.e. , the valve plate may work in normally open (NO) and normally closed (NC) configuration. For switching the valve into its other position or state, an electromagnetic coil is energized thereby creating a magnetic flux flowing through a static core and/or static yoke and the displaceable armature, which armature in general is pulled by the magnetic force against the spring bias thereby closing an air gap between the armature and the core.

In particular, a 3/2-way solenoid valve comprises fluid connection channels and an electromagnetic actuator, which have direct influence on behaviour of the valve. 3/2- way solenoid valves are used to close or distribute a gas or liquid in a pipe. In a not activated state, i.e., the basic state, the armature is pressed to a valve seat by a spring. In an activated state the armature moves to the core and plugs a fluid channel.

The efficiency of the magnetic circuits is generally limited. Further a high number of components is necessary, resulting in high costs. EP 3 633 252 A1 discloses a solenoid fluid valve, in particular for pneumatic applications, wherein said fluid valve comprises: an inner valve core extending along an axial direction, a movable part displaceable between a basic position and an activated position, for closing and opening at least one valve seat, an outer yoke, a spring for biasing said movable part into its basic position, an electromagnetic coil to be energized for creating a magnetic circuit flowing through said inner valve core, said outer yoke and said movable part, for switching said movable part into said activated position, wherein said inner valve core, said movable part and said outer yoke are made at least partially of a magnetic material, wherein said movable part is realized as a valve plate extending in radial direction beyond an end part of the inner valve core and comprising at least one sealing face for contacting at least one valve seat.

Therein, the movable part may move along a longitudinal axis of the solenoid valve. However, guiding the motion of the movable part along the longitudinal axis may be improvable to avoid tilting of the movable part and/or to enable a preferred alignment of the movable part in its basic and/or activated position.

The problem of the invention is to provide a technological contribution to the art. A specific embodiment of the present invention may solve the problem of providing a fluid valve which can be made with limited assembly effort and reduced number of components while enabling an improved performance in transitioning from the basic state to the active state and/or from the active state to the basic state.

This problem is solved by a solenoid valve according to claim 1 . The dependent claims describe preferred further developments.

According to an aspect of the present invention, a solenoid valve for pneumatic applications for a vehicle, in particular utility vehicle, is provided. Therein, said fluid valve comprises: an inner valve core extending along a longitudinal axis, valve plate displaceable between a basic position and an activated position, for closing and opening at least one valve seat, an outer yoke, a valve connection body with an inlet channel extending along the longitudinal axis, a spring for biasing said valve plate into its basic position, and an electromagnetic coil to be energized for creating a magnetic circuit flowing through said inner valve core, said outer yoke and said valve plate, for switching the valve plate into said activated position, wherein the valve inlet channel comprises at least three guiding ribs arranged around or at an outer cylindrical surface of the valve inlet channel and being distributed along a circumference of the valve inlet channel, wherein the at least three guiding ribs and an inner guiding contour of an annular protrusion of the valve plate are adapted to enable a vertical alignment of the valve plate with respect to the valve inlet channel when a linear displacement of the valve plate occurs due to an energization of the electromagnetic coil.

The solenoid valve may be, in particular, a pneumatic valve, in particular, a 3/2-valve. Further, it can be realized e.g. as a 2/2-valve or blocking valve.

The valve plate is provided as magnetic moveable part. The valve plate may be the only part which is displaced by the magnetic flux, together with the biasing spring. Therein, due to the magnetic flux, the valve plate may be transitioned between the basic position and the activated position and may thereby be displaced along the longitudinal axis.

The valve inlet channel comprises an outer cylindrical surface and the at least three guiding ribs protruding from the outer cylindrical surface radially outwardly with respect to the longitudinal axis. The ribs are adapted to provide an improved guiding of the valve plate and are thus distributed along the circumference of the outer cylindrical surface, i.e., along the circumference of the valve inlet channel. The valve plate comprises an annular protrusion, also called a rim, wherein the annular protrusion and the ribs are adapted to interact with each other to guide the displacement of the valve plate. Therein, the annular protrusion comprises the guiding contour as a radially inwardly facing surface section of the annular protrusion which may contact the, from the valve inlet channel, radially outwardly protruding ribs to achieve guiding the displacement of the valve plate.

Furthermore, the ribs are adapted to enable the vertical alignment of the valve plate with respect to the valve inlet channel. Thus, the ribs form a valve seat for the valve plate in which the valve plate may settle. By improving guiding the displacement of the valve plate, the magnetic circuit of the solenoid valve can be further improved, since the circumferentially distributed ribs provide guidance that impedes tilting of the valve plate. Thus, the valve plate remains oriented, so that magnetic flux can be efficiently coupled into the valve plate to induce a force thereon. The guidance by the at least three ribs allows to eliminate the possibility of a collision between metal parts and allows for a usage of standard magnetic steel instead of stainless steels with limited ferrous content.

Furthermore, the solenoid valve enables to realize higher air flows of the valve. The number of components may be reduced, in particular by removal of a guide rod and a possible replacement of the conventional armature with a valve plate. Thus, the costs may be reduced due to a simplified assembly, further removing the number of displaceable or moving components lead to an enhanced reliability and less wear or abrasion. Further an improvement of the functional relation, i.e., dependence, of the valve force on the stroke is possible due to the effective guiding of the displacement of the valve plate.

An advantage of the invention is therefore the reduced amount of valve components while maintaining the valve function, for example a 3/2 valve function or 2/2 valve function. The general physical principles of a conventional valve, e.g., a conventional 3/2 valve and the inventive valve plate are known in the art. As an additional feature, the solenoid valve presents an improved balance between performance and thermal loads and wear resulting in a possibility to extend the application range of the devices by moving the sealing elements outside of the heat source, which is the coil of the solenoid valve.

The invention enables higher forces in relation to the envelope dimensions of the valve, which results in the opportunity to use larger air flows (for example above NW 4 mm), further to a reduced size of contact surfaces, which results in extended life of the components and gives the opportunity to replace expensive stainless steel by cheaper steel with surface protection.

Preferably, the protrusion of the valve plate is an integrally formed part of the valve plate. In other words, the valve plate and the protrusion are one component. This may facilitate mounting the valve plate into the solenoid valve and achieves a steady connection between the annular protrusion and a remaining section of the valve plate, and thus improves guiding the valve plate.

Preferably, the solenoid valve comprises gaps being arranged between the at least three guiding ribs and the protrusion of the valve plate and forming a section of an air flow path connecting the valve inlet channel with an outlet channel. This embodiment has realized that the gaps may be used to release air from the inlet channel via the gaps towards the outlet channel. Therefore, alternative means to connect the valve inlet channel and the outlet channel with each other may be dispensed with.

Preferably, the at least ribs are, along the circumference, equidistantly separated from each other. In this embodiment, the guidance of the displacement of the valve plate is further improved, since the equidistant distribution of the ribs lead to a regular distribution of contact surfaces between the ribs and the annular protrusion to guide the valve plate. This embodiment achieves a particular effective reduction of any tendency of the valve plate to tilt against the longitudinal axis. Preferably, for this reason, the ribs comprise a rotational symmetry with respect to the longitudinal axis to provide a rotationally symmetric guidance for the valve plate.

Preferably, the valve plate and the valve core are arranged to form an annular air gap between a plate face side of the valve plate and a core face side of the valve core facing the plate face side, the plate face side comprises a protrusion and/or a recess, and the core face side comprises a complementary recess and/or a complementary protrusion so that the plate face side and the core face side mate with each other. This embodiment has realized that the dependence between force that is exerted on the valve plate and stroke, i.e. , the displacement of the valve plate, is improved by increasing the magnetic flux that is coupled into the valve plate. This is realized by shaping the plate face side and the core face side so that the plate face side and the core face side comprise complementary shape, i.e., the sides mate with each other. Therein, one of the sides comprises the protrusion and the other side comprises the complementary recess in which the protrusion may be arranged, e.g., in the basic position. Analogously, one of the sides comprises the recess and the other side comprises the complementary protrusion which may protrude into the recess, e.g., in the basic position. An alignment and a controlled orientation of the valve plate and the valve core is essential for mating the plate face side with the core face side by means of the complementary shape as explained above. By improving the magnetic flux an increased air gap and thus air flow may be realized. The magnetic flux is changing or varying relatively little, compared to a conventional system with a rod-shaped magnetic core and a rod-shaped moveable armature. Thus, a soft detaching is possible, which leads to a better valve behavior, less friction and less wear of the parts. Further, the typical stroke and acoustic shock is diminished. The suggested geometry of the core and the valve plate may induce an increase of force by, for example, 20 % to 30 % at a given magnetic flux that is assumed in the valve core.

Preferably, each of the plate face side and the core face side is rotationally symmetric. This embodiment enhances the efficiency of the manufacture of the valve plate and the valve core and of the mountability of the valve plate with the valve core.

Preferably, the plate face side and the core face side are adapted to comprise three separate magnetic contact sections in which, in the activated position, the distance between the plate face side and the core face side is smaller than the displacement of the valve plate between the activated position and the basic position. This embodiment comprises a comparatively simple geometry of the valve plate that allows an effective manufacture, and, at the same time, improves the exertion of the magnetic force on the valve plate considerably. Therein, a magnetic contact section is a section of the annular air gap in which the magnetic flux towards the valve plate is particularly increased compared to other section of the annular air gap.

Preferably, the valve plate comprises collar being arranged radially outwardly from the valve core. Due to the collar, the magnetic flux between the valve core and valve plate does not change so much as in the case of two parts opposite to each other in the moving direction.

Preferably, the collar comprises an inner surface being adapted to mate with the valve core in the basic position and to provide the annular air gap in the activated position. In other words, the collar of the valve plate protrudes along the longitudinal axis into the direction of the valve core. Similar to the plate face side and the valve face side, the collar, or circumferential rib, the stroke valve plate is further guided and the magnetic flux between the valve core and valve plate is further improved as the valve plate further surrounds the valve core.

Preferably, the solenoid valve comprises an exhaust port and an outlet port being fluidly connected by an outlet chamber, wherein the outlet chamber comprises a center, wherein the center is arranged off-axis with respect to the longitudinal axis of the solenoid valve. In other words, the solenoid valve comprises an asymmetric exhaust feature, wherein the center of the intermediate or temporary exhaust chamber does not match with the longitudinal axis of the solenoid valve to reduce whistling noise and eliminate backpressure.

Preferably, the solenoid valve further comprises an exhaust sealing washer, which is elastically deformable and/or flexible, so that pressurized air exiting via the exhaust port is not allowed a return or reverse flow, wherein, preferably, the exhaust sealing washer includes a plurality of slits, and/or wherein, preferably, the exhaust sealing washer is made of elastomer.

Preferably, the outlet chamber further comprises an exhaust cap such that the space between the exhaust sealing washer and the exhaust cap forms an intermediate exhaust chamber before the pressurized air exits via exhaust gaps.

Preferably, the plurality of slits are angular slits. I.e. , each of the slits comprises a principal elongation in a radial direction of the annular exhaust sealing washer. Each pair of slits is separated by an angle and/or a circumferential distance from each other. This enables an efficient manufacture, improves properties of the exhaust sealing washer.

Preferably, the solenoid valve comprises an inlet port being arranged in alignment with the longitudinal axis of the solenoid valve, and the inlet port is directly connected to the inlet channel. In other words, the inlet port matches with the longitudinal axis, which allows a better stacking of the valve, i.e., an arrangement of a plurality of solenoid valves, in relation to mounting holes present on two sides of the inlet port. Preferably, the valve plate comprises a rubber sealing pad, which is bonded or connected or glued or vulcanized to the valve plate, preferably, at a geometrically central portion of the valve plate. Particularly preferably, the rubber sealing pad is vulcanized to the valve plate. This enables a stable and robust connection to the metallic part of the valve plate.

According to an aspect of the present invention, a vehicle, in particular utility vehicle is provided. The vehicle, in particular utility vehicle, comprises the solenoid valve as described above. Therein, the solenoid valve may comprise one or more of the above described optional and/or preferable features to achieve a technical effect associated therewith.

The invention is hereinafter described in detail with reference to the appended drawings, in which:

Fig. 1 shows a cross-section of a solenoid valve according to an embodiment of the invention;

Fig. 2 shows a sectional view of a solenoid valve according to an embodiment of the invention illustrating guiding a valve plate;

Fig. 3 shows a perspective view of a solenoid valve according to an embodiment of the invention illustrating guiding a valve plate;

Fig. 4 shows a detail of a cross-section of a solenoid valve according to an embodiment of the invention;

Fig. 5 shows a diagram illustrating the spatial distribution of magnetic flux of a solenoid valve according to an embodiment of the invention;

Fig. 6 shows a diagram illustrating the spatial distribution of magnetic force between the valve plate and the valve core of a solenoid valve according to an embodiment of the invention;

Fig. 7 shows a schematic dependence of force on stroke of a valve plate of a solenoid valve according to an embodiment of the invention;

Fig. 8 shows a detail of a cross-section of a solenoid valve according to an embodiment of the invention;

Fig. 9 shows a schematic of a vehicle, in particular utility vehicle, according to an embodiment of the invention; Fig. 10 shows a top view of an exhaust sealing washer of a solenoid valve according to an embodiment of the invention; and

Fig. 11 shows a perspective view of an exhaust sealing washer of a solenoid valve according to an embodiment of the invention.

Figure 1 shows a cross-section of a solenoid valve 1 according to an embodiment of the invention.

The solenoid valve 1 comprises an inlet port 1a, an outlet port 1 b and an exhaust port 1c. The inlet port 1a and the outlet port 1 b are provided in a valve connection body (upper valve body) 2, which further comprises an inlet channel 3 extending from the inlet port 1a to an inlet valve seat 4, an outlet channel 5 extending from the inlet valve seat 4 to the outlet port 1b, mounting holes 6 for mounting the valve 1 . The inlet port 1a may also be a through port 50 to connect a plurality of solenoid valves 1 , which may be identical to each other and they may resemble the same structure as displayed for instance in Fig. 1 of the invention. The through port 50 allows a stackable concept in connection with mounting holes 6. The inlet port 1a and/or the through port 50 is arranged in alignment with a longitudinal axis A of the solenoid valve 1 .

The valve connection body 2 is connected to a lower valve body 10 comprising a valve coil body 11 and an overmolded plastic housing 12. The exhaust port 1c is provided in the overmolded plastic housing 12 and protected by an exhaust cap 14 fixed to the overmolded plastic housing 12.

The solenoid valve 1 comprises a yoke 15 in the lower valve body 10, or it is part of the lower valve body 10. Inside the yoke 15 a valve core 16 surrounding an exhaust channel 17 and a bobbin 18 surrounding the valve core 16 are provided. A valve coil 20 made of copper wire (not shown) is supported by the bobbin 18 and electrically connected to electrical pins 22, which extend in or through an electrical socket connection 24 for receiving an electrical plug (not shown in Fig. 1 ), said electrical socket connection 24 being formed in particular in the plastic housing 12.

The valve plate 8 is cup-shaped, i.e. , in particular annular, and comprises in its central area a vulcanized rubber sealing pad 25 with a (first) upper sealing face 25a and a (second) lower sealing face 25b (see also Figure 4). A spring 26, in particular a screw or a helical spring 26, is provided between the lower valve body 10 and the valve plate 8 and biases the valve plate 8 with its upper sealing face 25a against the inlet valve seat 4, thereby closing the inlet valve 4 and defining the non-activated basic position BP (see Figure 4). The rubber sealing pad 25 has been bonded, connected, glued or vulcanized to the valve plate 8 at a geometrically central portion of the valve plate 8.

In the non-activated closed basic position BP (see Figure 4), i.e. , with not energized coil 20, the spring 26 presses the upper sealing face 25a against the inlet valve seat 4 thereby blocking the inlet channel 3 and forming a lower air gap or merely a gap 52 between the plate 8 and the exhaust valve seat 28. This gap 52 enables venting of the air form the outlet port 1b to the exhaust port 1c. The inlet valve seat 4 is preferably formed with a valve cone 4a, serving as bumps for providing a defined sealing contact with the second sealing faces 25b of the rubber sealing pad 25.

In the actuated position AP as shown in Figure 1 , the valve seat 8 is pressed with its lower (second) sealing face 25b against an exhaust valve seat 28 formed by the valve core 16. In this open activated position AP air can flow from the open inlet valve seat 4 through the upper air gap 32, through an unrestricted flow path 48 formed by gaps 51 between the ribs 38 (see Figures 2 and 3), to the outlet channel 5 and then to the outlet port 1b. The exhaust valve seat 28 is closed by the second sealing face 25b pressing against the exhaust valve seat 28. In the activated position AP, end stops (not shown), or an end stop contour, realized from thermoplast material protect the valve plate 8 from mechanical damage during contact between the valve plate 8 and the yoke 15. An additional feature of the end stops 46 is to avoid the saturation of the magnetic circuit and so-called magnetic sticking effect between the valve plate 8 and the yoke 15.

In its peripheral areas the cup-shaped valve plate 8 comprises a circular spring recess 30 for receiving the spring 26 and a plate edge 45 (see Figure 4), which is preferably cylindrical and extends into the axial direction A. The plate edge 45 comprises a ring-shaped stop 45a, which may serve for contacting an adjacent yoke contact stop 15c in the activated position AP; however, this contact is only additional to the stop defined by the lower face 25b of the rubber sealing pad 25 contacting an end part 16a of the valve core 16, since in each position the valve plate 8 is pressed with its rubber sealing pad 25 against one of the valve seats 4, 28 in order to secure a tight sealing.

The valve inlet channel 3 comprises five guiding ribs 38 arranged around or at an outer cylindrical surface 39 of the valve inlet channel 3 as further explained with reference to Figures 2 and 3.

As shown in Figure 1 , the valve plate 8 comprises an annular protrusion 31 with an inner guiding contour 31a. The protrusion 31 extends along the axial direction A and is rotationally symmetric. The guiding ribs 38 are arranged radially outwardly from the inlet channel 3 so as to contact the inner guiding contour 31a of the valve plate 8. The guiding ribs 38 and an inner guiding contour 31 a of the annular protrusion 31 of the valve plate 8 are adapted to enable a vertical alignment of the valve plate 8 with respect to the valve inlet channel 3 when a linear displacement of the valve plate 8 occurs due to an energization of the electromagnetic coil 20. The alignment of the valve plate 8 with respect to the valve inlet channel 3 is shown in Figure 4. Thus, guidance and positioning of the valve plate 8 is realized by the guiding ribs 38 localized on the inlet channel 3, i.e. , on a cylindrical outer face with guiding ribs 38 localized preferably on the external part of the inlet channel 3 for guiding the displaceable valve plate 8. As shown in Figure 1 , the protrusion 31 of the valve plate 8 is an integrally formed part of the valve plate 8. I.e., the inner rim or protrusion 31 of the valve plate 8 is an integrally formed part of the valve plate 8. The guidance by means of the ribs 36 allows to eliminate the possibility of collision between metal parts and allows for usage of standard magnetic steel instead of stainless steels with limited ferrous content.

The valve 1 is switched from the basic position BP into its open activated position AP by energizing the coil 20 via the electrical socket connection 24 as shown in Figure 1. The coil 20 creates a magnetic flux 40 flowing in axial direction A along the core 16 to the valve plate 8, and back along the yoke 15 to the core 16, thereby forming a magnetic flux circuit 42. The magnetic force pulls the valve plate 8 downwards, against the bias of the spring 26, and thus the valve plate 8 contacts the exhaust valve seat 28 formed at the top of the core 16, thereby closing the lower air gap 52 and opening the upper air gap 32, as can be seen from Figure 1 .

This movement of the valve plate 8 between the activated position AP as shown in Figure 1 and the basic position BP as shown in Figure 4 is be guided by the outer face of the inlet channel 3 by the guiding ribs 38.

The valve core 16, the yoke 15 and the valve plate 8 are made from ferromagnetic metal, in particular, ferromagnetic steel, for defining the magnetic flow circuit 42.

Figure 2 shows a sectional view of a solenoid valve 1 according to an embodiment of the invention illustrating guiding a valve plate 8. Therein, Figure 2 shows a detail of the solenoid valve 1 of Figure 1 . Figure 2 is described under reference to Figure 1 and the description thereof. Therein, the longitudinal axis A points in the drawing plane (not indicated).

As shown in Figure 2, the valve inlet channel 3 comprises an outer cylindrical surface 39. Therein, the outer cylindrical surface 39 is rotationally symmetric with respect to the longitudinal axis A. The outer cylindrical surface 39 comprises a circumference 39a being perpendicular to the longitudinal axis A.

The solenoid valve 1 comprises the plurality of ribs 38 being distributed along the circumference 39a of the valve inlet channel 3. Between any pair of ribs 38, a gap 51 is formed. For an illustrative purpose, only two of the ribs 38 and two of the gaps 51 are indicated in Figure 2.

Each of the ribs 38 projects radially outwardly, with respect to the longitudinal axis A, from the cylindrical surface 39. The ribs 38 are, along the circumference 39a, equidistantly separated from each other. Thus, the gaps 51 are, along the circumference 39a, equidistantly separated from each other and have the same size and shape.

The valve plate 8 comprises the annular protrusion 31 with the inner guiding contour 31 a. The inner guiding contour 31 a is a radially inwardly surface of the annular protrusion 31 . The inner guiding contour 31a and the ribs 38 may be in contact with each other to guide the valve plate 8 when transitioning between the activated position AP and the basic position BP and experiencing a stroke S thereby.

Figure 3 shows a perspective view of a solenoid valve 1 according to an embodiment of the invention illustrating guiding a valve plate 8. Figure 3 shows a perspective view of a detail of the solenoid valve 1 of Figures 1 and 2. As can be seen in Figure 3, a flow patch is separated from the magnetic circuit, resulting in less magnetic force loss.

The solenoid valve 1 comprises the gaps 51 being arranged between the guiding ribs 38 and the protrusion 31 of the valve plate 8 and forming a section of the air flow path 48 connecting the valve inlet channel 3 with an outlet channel 5.

Figure 4 shows a detail of a cross-section of a solenoid valve 1 according to an embodiment of the invention. Figure 4 shows a detail of the solenoid valve 1 of Figures 1 to 3. Figure 4 is described under reference to Figures 1 to 3.

As shown in Figure 4, the ribs 38 are localized on an external part of the inlet channel 3 contacting the inner perimeter of the inner guiding contour 31a of the valve plate 8. In particular, a guidance can be realized by the inner guiding contour 31a sliding along the ribs 38 formed at the valve inlet channel 3 in the upper valve body 2. The inner plate contour ribs 38 are provided for guiding the valve plate 8, in particular the inner guiding contour 31 a of said valve plate 8, thereby enabling a magnetic flow between said valve plate 8 and the outer yoke 15 during the displacement of said valve plate 8. This enables a continuous magnetic flow between them without sudden change.

In the basic position BP, the valve plate 8 and the valve core 16 are arranged to form an annular air gap 52 between a plate face side 54 of the valve plate 8 and a core face side 53 of the valve core 16. The core face side 53 faces the plate face side 54, i.e. , the core face side 53 and the plate face side 54 are separated from each by the annular air gap 52. In the basic position BP, the annular air gap 52 is arranged between the core face side 53 and the plate face side 54. The plate face side 54 comprises a protrusion 55 and a recess 56. The core face side 53 comprises a complementary recess 57 and a complementary protrusion 58 so that the plate face side 54 and the core face side 53 mate with each other. Each of the plate face side 54 and the core face side 53 is rotationally symmetric.

The valve plate 8 comprises collar 59 being arranged radially outwardly from the valve core 16. The collar 59 comprises an inner surface 59a being adapted to mate with the valve core 16 in the basic position BP and to provide the annular air gap 52 in the activated position AP. An advantage of the collar 59 is its magnetic performance for the magnetic flux 40 flow characteristic. The magnetic flux 40 flows from the end part 16a (top part) of the valve core 16 via the annular air gap 52 to the bottom face of the valve plate 8. If the upper air gap 32 is to be closed by the magnetic force F is formed as depicted in Figure 1 , then the magnetic force F is dependent on the stroke S. In the prior art, this results in a steep increase of the magnetic force when energizing the coil 20, which then results in a stroke-like displacement of the valve plate 8. However, with the collar 38 surrounding a valve core 16 at the end part 16a, the magnetic flux 40 therefore can flow in axial direction A and a transverse direction, i.e. , partially in radial direction from the top area 16a of the valve core 16 to the collar 38.

Figure 5 shows a diagram illustrating the spatial distribution of magnetic flux 40 of a solenoid valve 1 according to an embodiment of the invention. The solenoid valve 1 is described with reference to Figures 1 to 4. Figure 5 is described under reference to Figures 1 to 4. Therein, it is assumed that an average field strength plate face side 54 of the valve core 16 is 1 ,5 T.

The plate face side 54 and the core face side 53 are adapted to comprise three separate magnetic contact sections 60 in which, in the activated position AP, the distance between the plate face side 54 and the core face side 53 is smaller than the displacement of the valve plate 8 between the activated position AP and the basic position BP.

The three magnetic contact section 60 result in increased flux in the annular gap 52 by 30 % compared to the prior art. Thus due to a plate design with the mating plate face side 54 and core face side 53 and the collar 59, the initial stroke S of the valve plate 8 is partially “parallel" to the valve core 16 and thus the magnetic flux 40 between the valve core 16 and valve plate 8 may remain almost constant and/or only slightly on the stroke S. Thus, the force F on stroke S dependence may flatten to improve the characteristics of the solenoid valve 1 .

Figure 6 shows a diagram illustrating the spatial distribution of magnetic flux 40 between the valve plate 8 and the valve core 16 of a solenoid valve 1 according to an embodiment of the invention. Therein, the solenoid valve 1 is the solenoid valve 1 as described with reference to Figures 1 to 5. Figure 6 is described under reference to Figures 1 to 5.

As shown in Figure 6, the magnetic flux 40 forms a magnetic circuit 42 that flows through the inner valve core 16, the outer yoke 15 and the movable part 8. A force F is thus exerted in particular on the valve plate 8 for displacing the valve plate 8 by a initial stroke distance delta_s.

Figure 7 shows a schematic dependence of force F on stroke S of a valve plate 8 of a solenoid valve 1 according to an embodiment of the invention.

In the prior art, the steep force over stroke characteristic causes a rapid loss of force during the increasing stroke, which directly limits the maximum width of the annular air gap created by the conventional armature and valve seat and maximum force of the spring, which presses the armature onto the valve seat. The maximum spring force has direct impact on the value of the maximum air flow in the valve, i.e. the efficiency of the valve. In such a design the force generated by the electromagnetic circuit can be increased only by enlarging the circuit components, which is a very expensive approach. The amount of necessary components is known and there is no other opportunity to increase the created coil force to reduce high flow valve cost.

The characteristic curve of the dependence between force F and stroke S of a solenoid valve 1 as described with reference to Figure 1 to 6 is shown in Figure 7. The valve plate 8 moves upwards, i.e. the stroke S of the annular air gap 52 is increasing, the force F is initially decreasing, since the annular air gap 52 weakens the magnetic flux 40. However, when the stroke S is further increasing, the decrease is stopped, and it may flatten out, since the magnetic flux 40 can flow in transverse direction, i.e., perpendicular to the longitudinal axis A, through the annular air gap 52. This enables a softer transition of the displacement movement.

Figure 8 shows a detail of a cross-section of a solenoid valve 1 according to an embodiment of the invention. Therein, the Figure 8 shows a detail of an exhaust of the solenoid valve 1 as described with reference to Figures 1 to 7. Therein, Figure 8 particularly illustrates the exhaust cap 14. The exhaust port 1c and the outlet port 1b are fluidly connected by an outlet chamber 9. The outlet chamber 9 comprises a center 9a (only indicated schematically). The center 9a is arranged off-axis with respect to the longitudinal axis A of the solenoid valve 1 . The location of the center 9a may be determined by the center 9a of the volume of the outlet chamber 9. The off-axis arrangement of the center 9a and the chamber 9 lead to an asymmetrical exhaust with reduced whistling noise, reduced back-pressure, due to large diameter that is achievable and an effective two-piece design of the exhaust cap 14.

The solenoid valve comprises an exhaust sealing washer 47. The exhaust sealing washer 47 is also shown in and described with reference to Figures 10 and 11 . The exhaust sealing washer 47 as shown in Figure 8 is annularly shaped and/or discshaped and comprises a through-hole 9g (not indicated in Figure 8, see Figures 10 and 11 ). A stem 9e of the plastic housing 12 projects through the through hole 9g to fixate the exhaust sealing washer 47.

The exhaust sealing washer 47 is made of an elastomer, e.g., rubber. The exhaust sealing washer 47 is elastically deformable and flexible so that pressurized air exiting via the exhaust port 1c is not allowed a return or reverse flow.

The exhaust cap 14 is arranged and adapted such that a space 9g between the exhaust sealing washer 47 and the exhaust cap 14 forms an intermediate exhaust chamber 9c before the pressurized air exits via exhaust gaps 9d forming the exhaust port 1c.

Figure 9 shows a schematic of a vehicle 100a, in particular utility vehicle 200b, according to an embodiment of the invention. The vehicle 100a, in particular utility vehicle 200b is a motor vehicle, in particular a land vehicle. The vehicle 100a, in particular utility vehicle 200b, comprises a pneumatic system (not shown) such as a pneumatic brake system and/or a pneumatic air system, which comprises a solenoid valve 1 as described with reference to any of Figure 1 to 8 and the description thereof.

Figure 10 shows a top view of an exhaust sealing washer 47 of a solenoid valve 1 according to an embodiment of the invention. The exhaust sealing washer 47 is the exhaust sealing washer 47 as also shown in Figure 8. Figure 10 is described under reference to Figure 8.

The exhaust sealing washer 47 includes a plurality of slits 9f. The plurality of slits 9f are angular slits 9f. The slits 9f are distributed with equal angular distances between each other.

The exhaust sealing washer 47 comprises the though-hole 9h as explained with reference to Figure 8.

Figure 11 shows a perspective view of an exhaust sealing washer 47 of a solenoid valve 1 according to an embodiment of the invention. The exhaust sealing washer 47 is the exhaust sealing washer 47 as also shown in Figures 8 and 10. Figure 11 is described under reference to Figures 8 and 10. List of reference signs (part of the description)

1 solenoid valve, pneumatic 3/2-valve

1a inlet port

1 b outlet port

1 c exhaust port

2 valve connection body, upper valve body

3 inlet channel

4 inlet valve seat

4a first valve cone

5 outlet channel

6 mounting holes

8 displaceable valve plate

9 outlet chamber

9a center

9c an intermediate exhaust chamber

9d exhaust gaps

9e stem

9f slit

9g space

9h through hole

10 lower valve body

11 valve coil body

12 overmolded plastic housing

14 exhaust cap

15 yoke

15a cylindrical part of yoke 15

15b bottom part of yoke 15, radially extending to the valve core 16

15c contact stop of yoke (upper face of the yoke 15) for stopping valve plate 8

16 valve core

16a end part, in particular top part of the valve core 16

17 exhaust channel

18 bobbin valve coil electrical pins electrical socket connection rubber sealing pad a first face b second face screw spring valve seat circular spring recess of the valve plate 8 for receiving the spring 26 protrusion or inner rim, provided at or being part of valve plate 8a guiding contour of valve plate 8, preferably at protrusion 31 upper air gap, upper air gap, between plate 8 and inlet valve seat 4 guiding ribs formed at valve inlet channel 3 in upper valve body 2 cylindrical surface a circumference magnetic flux magnetic circuit central recess in the bottom face of the valve plate 8

(outer) edge of the valve plate 8 a stop of the valve plate 8 for contacting the yoke contact stop 15c exhaust sealing washer flow path through port gap annular air gap, between the plate 8 and the exhaust valve seat 28 plate face side core face side protrusion of plate face side 54 recess of plate face side 53 complementary recess of core face side 54 complementary protrusion of core face side 53 59 collar

59a inner surface

60 magnetic contact section

100a vehicle

100b utility vehicle

A longitudinal axis, axial direction delta_s initial stroke distance AP activated position

BP basic position

F force

S stroke

Claims

1. Solenoid valve (1) for pneumatic applications for a vehicle (100a), in particular utility vehicle (100b), wherein said fluid valve (1 ) comprises:

- an inner valve core (16) extending along a longitudinal axis (A),

- a valve plate (8) displaceable between a basic position (BP) and an activated position (AP), for closing and opening at least one valve seat (4),

- an outer yoke (15),

- a valve connection body (2) with an inlet channel (3) extending along the longitudinal axis (A),

- a spring (26) for biasing said valve plate (8) into its basic position, and

- an electromagnetic coil (20) to be energized for creating a magnetic circuit (42) flowing through said inner valve core (16), said outer yoke (15) and said valve plate (8), for switching the valve plate (8) into said activated position,

- an exhaust port (1c), characterized in that

- the valve inlet channel (3) comprises at least three guiding ribs (38) arranged around or at an outer cylindrical surface (39) of the valve inlet channel (3) and being distributed along a circumference (39a) of the valve inlet channel (3), wherein

- the at least three guiding ribs (38) and an inner guiding contour (31a) of an annular protrusion (31 ) of the valve plate (8) are adapted to enable a vertical alignment of the valve plate (8) with respect to the valve inlet channel (3) when a linear displacement of the valve plate (8) occurs due to an energization of the electromagnetic coil (20).

2. The solenoid valve (1 ) as claimed in claim 1 , wherein the protrusion (31 ) of the valve plate (8) is an integrally formed part of the valve plate (8).

3. The solenoid valve (1 ) as claimed in claim 1 or 2, wherein the solenoid valve (1 ) comprises gaps (51) being arranged between the at least three guiding ribs (38) and the protrusion (31 ) of the valve plate (8) and forming a section of an air flow path connecting the valve inlet channel (3) with an outlet channel (5).

4. The solenoid valve (1 ) as claimed in any one of the preceding claims, wherein the at least three guiding ribs (38) are, along the circumference (39a), equidistantly separated from each other.

5. The solenoid valve (1 ) as claimed in any one of the preceding claims, wherein

- the valve plate (8) and the valve core (16) are arranged to form an annular air gap (52) between a plate face side (54) of the valve plate (8) and a core face side (53) of the valve core (16) facing the plate face side (54),

- the plate face side (54) comprises a protrusion (55) and/or a recess (56), and

- the core face side (53) comprises a complementary recess (57) and/or a complementary protrusion (58) so that the plate face side (54) and the core face side (53) mate with each other.

6. The solenoid valve (1 ) as claimed in claim 5, wherein each of the plate face side (54) and the core face side (53) is rotationally symmetric.

7. The solenoid valve (1 ) as claimed in claim 5 or 6, wherein the plate face side (54) and the core face side (53) are adapted to comprise three separate magnetic contact sections (60) in which, in the activated position (AP), the distance between the plate face side (54) and the core face side (53) is smaller than the displacement of the valve plate (8) between the activated position (AP) and the basic position (BP).

8. The solenoid valve (1 ) as claimed in any one of claims 5 to 7, wherein the valve plate (8) comprises a collar (59) being arranged radially outwardly from the valve core (16).

9. The solenoid valve (1 ) as claimed in claim 8, wherein the collar (59) comprises an inner surface (59a) being adapted to mate with the valve core (16) in the basic position (BP) and to provide the annular air gap (52) in the activated position (AP).

10. The solenoid valve (1 ) as claimed in any one of the preceding claims, wherein the solenoid valve (1), apart from said exhaust port (1c), further comprises an outlet port (1 b) being fluidly connected by an outlet chamber (9), wherein the outlet chamber (9) comprises a center (9a), wherein the center (9a) is arranged off-axis with respect to the longitudinal axis (A) of the solenoid valve (A).

11 . The solenoid valve (1 ) as claimed in any one of claims 1 to 10, wherein the solenoid valve (1 ) further comprises an exhaust sealing washer (47), which is elastically deformable and/or flexible, so that pressurized air exiting via the exhaust port (1c) is not allowed a return or reverse flow, wherein, preferably, the exhaust sealing washer (47) includes a plurality of slits (9f), and/or wherein, preferably, the exhaust sealing washer (47) is made of elastomer.

12. The solenoid valve (1 ) as claimed in claim 11 and claim 10, wherein the outlet chamber (9) further comprises an exhaust cap (14) such that a space (9g) between the exhaust sealing washer (47) and the exhaust cap (14) forms an intermediate exhaust chamber (9c) before the pressurized air exits via exhaust gaps (9d).

13. The solenoid valve (1 ) as claimed in claim 11 or 12, wherein the plurality of slits (9f) are angular slits (9f).

14. The solenoid valve (1 ) as claimed in any one of the preceding claims, wherein the solenoid valve (1) comprises an inlet port (1a) being arranged in alignment with the longitudinal axis (A) of the solenoid valve (1 ), and wherein the inlet port (1a) is directly connected to the inlet channel (3).

15. The solenoid valve (1 ) as claimed in any one of the preceding claims, wherein the valve plate (8) comprises a rubber sealing pad (25), which is bonded or connected or glued or vulcanized to the valve plate (8), preferably, at a geometrically central portion of the valve plate (8).