Solenoid valve, especially for slip-controlled motor vehicle braking systems

Abstract

Electromagnetic valve, in particular for slip-controlled motor vehicle braking systems, with a valve tappet (4) arranged in a valve housing (3) which is capable of opening or closing a valve passage in a valve seat (5) of the valve housing (3), with a magnetic armature (1; 2) provided for actuating the valve tappet (4), and with a return spring (10) for positioning the valve tappet (4) in a basic position opening the valve passage, characterized in that the magnetic armature (1;2) is constructed in multiple parts, consisting of a first and a second armature (1, 2), both of which are decoupled from each other by means of an elastic element (7) and arranged coaxially and relatively movable relative to each other in the valve housing (3), wherein, depending on the magnitude of the electromagnetic excitation of the magnetic armature, either a magnetic force component is effective on the first armature (1) lifting the valve tappet (4) from the valve seat (5), or, in the opposite direction, a magnetic force component can be generated on the second armature (2) moving the valve tappet (4) onto the valve seat (5).

Description

[0001] The invention relates to an electromagnetic valve, in particular for slip-controlled motor vehicle braking systems, according to the preamble of claim 1.

[0002] From DE 10 2014 225 251 A1, an electromagnetic valve of the type specified is already known, comprising a valve tappet movably arranged in a valve housing, which is able to open or close a valve passage in a valve seat of the valve housing, a magnetic armature provided for actuating the valve tappet, and a return spring for positioning the valve tappet in a basic position opening the valve passage, for which purpose the return spring is supported against a stop in the valve housing.

[0003] Furthermore, an electromagnetic valve for motor vehicle brake systems is known from DE 10 2017 201 470 A1, comprising a valve tappet arranged in a valve housing, which is able to open or close a valve passage in a valve seat of the valve housing, and a magnetic armature provided for actuating the valve tappet, wherein the magnetic armature is multi-part, consisting of a first and a second armature, both of which are coaxially and relatively movable relative to each other in the valve housing by means of an elastic element.

[0004] The object of the present invention is now to further develop and improve the solenoid valve of the specified type in a cost-effective manner using the simplest possible functional means, such that with minimal electromagnetic excitation both sensitive pressure control in the sense of minimizing the valve flow rate is possible and, if necessary, a valve opening beyond the open basic position can be achieved by increasing the excitation current.

[0005] This problem is solved according to the invention for the solenoid valve of the specified type by the features of claim 1, according to which a new constructive and functional design of the magnetic armature is now presented, which includes a magnetic force component that closes the valve, but at the same time enables the valve to be fully opened with a low holding current, which is why two movably aligned armatures are now provided, which are connected by an elastic element in such a way that the magnetic force of the armature closing the valve passage only opposes the magnetic force of the other armature that fully opens the valve passage in a force-limited manner.

[0006] Further features and advantages of the invention will become apparent from the following description of an exemplary embodiment with reference to several drawings.

[0007] They show: Fig. 1 a longitudinal section through a first embodiment of the solenoid valve according to the invention, Fig. 2 a longitudinal section through a second embodiment of the solenoid valve according to the invention in the electromagnetically unexcited basic position, in which the valve seat is released by a defined first stroke from the valve tappet. Fig. 3 the solenoid valve after Fig. 2 in an electromagnetically excited intermediate position of the valve tappet with a low current, in which the valve seat is contacted by the valve tappet without exerting a closing force, Fig. 4 the solenoid valve after Fig. 3 in an end position of the valve tappet initiated by the low current, in which a closing force is exerted from the valve tappet to the valve seat by the tensioning of an elastic element, Fig. 5 the solenoid valve after Fig. 2 in an electromagnetically excited intermediate position of the valve tappet with a high current, in which the armature facing the magnetic core contacts a driver arranged on the valve tappet, Fig. 6 the solenoid valve after Fig. 5 in an end position of the valve tappet reached under the influence of the high current, in which the armature remains in an end position on the magnetic core, in which the valve seat is released by the valve tappet by a stroke that is greater than that in Fig. 2 opening strokes shown.

[0008] The Fig. Figure 1 shows a first embodiment of the invention by means of a longitudinal section through a solenoid valve having two independently actuated armatures 1, 2. The solenoid valve has a valve passage arranged on the inlet side of a valve seat 5 of the valve housing 3, which is opened by a defined stroke by means of a valve plunger 4 arranged on the second armature 2 as long as a valve coil 17 mounted on the valve housing 3 is inactive. Depending on the magnitude of the electric current, a valve outlet 16 arranged transversely to the valve seat 5 in the valve housing 3 can be hydraulically connected by means of the valve coil 17 to the variably adjustable valve passage in the valve seat 5.

[0009] In the present embodiment, a magnetic core 12 inserted at the end into the valve housing 3 is pressed into an austenitic connecting tube as a sealing plug, which is welded as part of the valve housing 3 to a thick-walled, magnetic flux-conducting tube body of the valve housing 3, which ensures secure fastening in a valve receiving bore of a valve receiving body.

[0010] According to the invention, the magnetic armature is constructed in multiple parts, consisting of a first and a second armature 1, 2, both of which are decoupled from each other by means of an elastic element 7 and arranged coaxially and relatively movable to each other in the valve housing 3, wherein, depending on the magnitude of the electromagnetic excitation of the magnetic armature, either a magnetic force component is effective on the first armature 1, lifting the valve tappet 4 from the valve seat 5, or, in the opposite direction, a magnetic force component can be generated on the second armature 2, moving the valve tappet 4 onto the valve seat 5.

[0011] The valve tappet 4 is flexibly connected to the second anchor 2 in the stroke direction via the elastic element 7, which in the example is shown below. Fig. 1 is formed by a tension spring which is connected at its inner diameter to the valve tappet 4 and at its outer diameter to a sleeve 9 which is preferably frictionally fixed in the second anchor 2.

[0012] The second armature 2 faces an inner end face 8 of the valve housing 3, which acts as a magnetic pole surface, in the direction of the valve seat 5. According to the design of the solenoid valve according to Fig. 1 In a stepped bore of the magnetic pole surface, the return spring 10, directed towards the sleeve 9, is located, by which, in coaxial alignment to the elastic element 7 in the illustrated, electromagnetically unexcited state of the second armature 2, the valve tappet 4 is lifted from the valve seat 5 by a defined amount.

[0013] Starting from Fig. In the electromagnetically excited state, the elastic element 7 arranged inside the sleeve 9 is elastically prestressed to tensile stress by means of a small electric current as a result of a stroke movement of the second armature 2 directed towards the inner end face 8 of the valve housing 3, so that with simultaneous compression of the return spring 10 the valve tappet 4 contacts the valve seat 5.

[0014] Depending on the stroke of the second anchor 2 and a tensile force generated in the elastic element 7 during the anchor stroke, the valve seat 5 is consequently subjected to a defined closing force by the valve tappet 4.

[0015] According to the Fig. Within the sleeve 9, the first armature 1, which is directly connected to the valve tappet 4, is guided section by section. Its end face, which is opposite the sleeve 9, faces the magnetic core 12 inserted into the end of the valve housing 3. A compression spring 11 directed towards the first armature 1 is arranged on the magnetic core 12. This spring force is set by means of a bolt 13 pressed into the magnetic core 12. The spring force is dimensioned such that, under a small electromagnetic excitation acting in the valve opening direction, the first armature 1 remains unchanged in a position opposite to a magnetic force acting on the second armature 2 in the valve closing direction. In this position, the first armature 1 has a defined axial distance to the magnetic core 12.

[0016] If, as a result of electromagnetic excitation of the first armature 1, the magnetic core 12 is contacted by the first armature 1 with a now increased electric current that exceeds the spring force of the compression spring 11, under tensile stress of the elastic element 7, the valve tappet 4 is lifted from the valve seat 5 by the stroke of the first armature 1, while the second armature 2 remains at the inner end face 8 of the valve housing 3, which acts as a magnetic pole surface, as a result of the electromagnetic excitation.

[0017] The Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. Six each show a constructive modification of the one in Fig. 1 shown solenoid valve, according to which the elastic element 7 replaces the one made of Fig. 1 known tension spring now in the Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. 6 is designed as a compression spring, which is arranged between the second armature 2 and a stop 14 of the valve tappet 4. The basic arrangement of the two armatures 1, 2 in the valve housing 3 does not differ from the illustration in Fig. 1. Likewise, the representation of the valve housing 3 corresponds to the Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. 6 unchanged from the Fig. 1 known embodiment, so that in the following regarding the Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. 6 In addition to the known features, only the essential differences are explicitly highlighted.

[0018] The Fig. 2 shows the solenoid valve analogously to Fig. 1 in electromagnetically non-excited valve basic position, after which identical to Fig. 1 the second armature 2 is axially spaced from an inner end face 8 of the valve housing 3 which acts as a magnetic pole surface, wherein the second armature 2, under the action of a return spring 10 inserted in the stepped bore of the valve housing 3, contacts a second stop 15 on its armature end face facing away from the elastic element 7, which is thus provided between the first armature 1 and the second armature 2 on the valve tappet 4, which, as a result of the action of the return spring 10, is lifted from the valve seat 5 by a defined basic setting of the valve lift.

[0019] The Fig. 3 shows following Fig. 2 The solenoid valve is initially subjected to electromagnetic excitation of the second armature 2 with a small current, causing the valve seat 5 to initially move without force into an intermediate stroke position and subsequently as shown in the illustration. Fig. 4 by tensioning the elastic element 7 with a defined closing force from the valve tappet 4, so that the return spring 10 and the elastic element 7 are subjected to compression until the second armature 2 abuts the inner end face 8 designed as a magnetic pole.

[0020] The Fig. 5 shows following Fig. 4. The solenoid valve is activated by an electromagnetic excitation of the second armature 2 with an increased electric current, causing the first armature 1 to reach an intermediate position in the valve housing 3 before contacting the magnetic core 12, opposite to the stroke direction of the second armature 2. In this position, the end face of the first armature 1 facing the magnetic core 12 contacts a driver 6 located at the end of the valve tappet 4 furthest from the valve seat 5. In this intermediate position, the valve seat 5 remains closed by the valve tappet 4 due to the magnetic force acting on the second armature 2.

[0021] Only upon reaching the in Fig. In the end position of the first armature 1 shown in Figure 6, in which the first armature 1 is in contact with the magnetic core 12 due to the high electrical excitation current, the valve tappet 4 is lifted from the valve seat 5 by a dimension that is greater than that shown in Figure 6. Fig. 2 shows the original opening dimension between the valve seat 5 and the valve tappet 4 in the electromagnetically unexcited valve position.

[0022] Thus, based on the data in the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. The 6 shown solenoid valves realize different valve strokes for electrically de-energized and highly energized operating conditions without a higher electromagnetic excitation leading to an increase in force in both stroke directions of the armatures 1, 2 which are advantageously decoupled by the elastic elements 7. Reference symbol list 1 anchor 2 anchors 3 Valve housings 4 valve tappets 5 valve seat 6 drive wheels 7 Element 8 Inner end face 9 sleeve 10 Return spring 11 Compression spring 12 magnetic cores 13 bolts 14 attacks 15 strikes 16 Valve outlet 17 Valve coil

Claims

Electromagnetic valve, in particular for slip-controlled motor vehicle braking systems, with a valve tappet (4) arranged in a valve housing (3), which is capable of opening or closing a valve passage in a valve seat (5) of the valve housing (3), with a magnetic armature (1; 2) provided for actuating the valve tappet (4), and with a return spring (10) for positioning the valve tappet (4) in a basic position opening the valve passage, characterized in that the magnetic armature (1;2) is constructed in multiple parts, consisting of a first and a second armature (1, 2), both of which are decoupled from each other by means of an elastic element (7) and arranged coaxially and relatively movable relative to each other in the valve housing (3), wherein, depending on the magnitude of the electromagnetic excitation of the magnetic armature, either a magnetic force component is effective on the first armature (1) lifting the valve tappet (4) from the valve seat (5), or, in the opposite direction, a magnetic force component can be generated on the second armature (2) moving the valve tappet (4) onto the valve seat (5). Electromagnetic valve according to claim 1, characterized in that the valve plunger (4) is flexibly connected to the second armature (2) in the stroke direction via the elastic element (7). Electromagnetic valve according to claim 1 or 2, characterized in that the elastic element (7) is formed by a tension spring which is connected at its inner diameter to the valve plunger (4) and at its outer diameter to a sleeve (9) which is preferably frictionally fixed in the second armature (2). Electromagnetic valve according to claim 3, characterized in that the second armature (2) is directed towards the valve seat (5) of an inner end face (8) of the valve housing (3) acting as a magnetic pole surface, in whose stepped bore the return spring (10) directed towards the sleeve (9) is supported, by which, in coaxial orientation to the elastic element (7), the valve tappet (4) is lifted from the valve seat (5) by a defined stroke in the electromagnetically unexcited state of the second armature (2). Electromagnetic valve according to claim 3, characterized in that, in the electromagnetically excited state, the elastic element (7) arranged inside the sleeve (9) is elastically prestressed to tensile stress by means of a small electric current as a result of a stroke movement of the second armature (2) directed towards an inner end face (8) of the valve housing (3) acting as a magnetic pole surface, so that, with simultaneous compression of the return spring (10), the valve seat (5) is contacted by the valve tappet (4). Electromagnetic valve according to claim 5, characterized in that, depending on the stroke of the second armature (2) and a tensile force generated in the elastic element (7) during the armature stroke, the valve seat (5) is acted upon by the valve plunger (4) with a defined closing force. Electromagnetic valve according to claim 3, characterized in that within the sleeve (9) the first armature (1) which is directly connected to the valve plunger (4) is guided section by section, the first armature (1) being directed with its end face away from the sleeve (9) towards a magnetic core (12) inserted into the valve housing (3), on which a compression spring (11) directed towards the first armature (1) is arranged, the spring being set to a spring force by means of a bolt (13) pressed into the magnetic core (12) which is dimensioned such that, under a small electromagnetic excitation acting in the valve opening direction, the first armature (1) remains unchanged in a position in which the first armature (1) has a defined axial distance to the magnetic core (12), against a magnetic force acting on the second armature (2) in the valve closing direction. Electromagnetic valve according to claim 7, characterized in that the magnetic core (12) is contacted by the first armature (1) under tensile stress of the elastic element (7) as a result of electromagnetic excitation of the first armature (1) with a high electric current exceeding the spring force of the compression spring (11), whereby the valve plunger (4) is lifted from the valve seat (5) by the stroke of the first armature (1), while the second armature (2) remains in contact with the inner end face (8) of the valve housing (3) as a result of the electromagnetic excitation. Electromagnetic valve according to claim 1, characterized in that the elastic element (7) is formed by a compression spring which is arranged between the second armature (2) and a stop (14) of the valve plunger (4). Electromagnetic valve according to claim 9, characterized in that in the electromagnetically unexcited valve basic position the second armature (2) is axially spaced from an inner end face (8) of the valve housing (3) acting as a magnetic pole surface and, under the action of a return spring (10), contacts a second stop (15) on its armature end face facing away from the elastic element (7), which is provided between the first armature (1) and the second armature (2) on the valve tappet (4), which is lifted from the valve seat (5) by a defined amount as a result of the action of the return spring (10). Electromagnetic valve according to claim 9, characterized in that, by electromagnetic excitation of the second armature (2) with a small current, the valve seat (5) is first acted upon without force in a first step and then, in a second step, by tensioning the elastic element (7) with a defined closing force from the valve plunger (4), for which purpose a return spring (10) is subjected to compression in the first step and the elastic element (7) is subjected to compression in the second step, before the second armature (2) remains at an inner end face (8) of the valve housing (3) designed as a magnetic pole. Electromagnetic valve according to claim 9, characterized in that by electromagnetic excitation of the second armature (2) with a high electric current, opposite to the stroke direction of the second armature (2), the first armature (1) reaches an intermediate position in the valve housing (3) before contacting the magnetic core (12), in which the first armature (1) contacts a driver (6) with its end face facing the magnetic core (12), which is provided at the end of the valve plunger (4) facing away from the valve seat (5). Electromagnetic valve according to claim 12, characterized in that in the intermediate position of the first armature (1) the valve seat (5) is closed by the valve plunger (4). Electromagnetic valve according to claim 12, characterized in that when the first armature (1) is applied to the magnetic core (12), the valve plunger (4) is lifted from the valve seat (5) by a dimension that is greater than the opening dimension between the valve seat (5) and the valve plunger (4) in the electromagnetically unexcited valve position.

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