Method for manufacturing a valve armature of an electromagnetic valve, valve armature and electromagnetic valve

Abstract

The invention relates to a valve armature of an electromagnetic valve, which valve armature has an armature body (18) with a blind hole (22) in which an elastomer seal (20) is vulcanized. The armature body (18) is produced in a cold forming process, in which the final axial length dimension (l) of the armature body (18) is also determined. The invention also relates to a valve having such a valve armature.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an armature for a solenoid valve, the armature, and the solenoid valve. Background Technology

[0002] Known solenoid valves, particularly lift-type armature valves, are equipped with an armature that moves linearly via an actuator, and the armature has an elastomeric seal at one end that works in conjunction with the valve seat to allow or interrupt fluid flow.

[0003] This type of valve armature is typically manufactured using machining methods. Summary of the Invention

[0004] The purpose of this invention is to accelerate the manufacturing process of the armature used in solenoid valves and reduce manufacturing costs.

[0005] The objective is achieved by a method for manufacturing a valve armature for a solenoid valve, the valve armature having an armature body and an elastomeric seal fastened thereto, the method comprising the following steps: A cylindrical blank is formed in a cold forming process to achieve the final axial length dimension of the armature body, wherein a blind hole is formed at one end of the blank and a valve seat side end face is formed around the blind hole. The elastomeric seal is vulcanized on the inner circumferential side of the blind hole.

[0006] Vulcanization is understood as the process by which the elastomeric material of the elastomeric seal in the component, specifically in the armature, is vulcanized at its final location, wherein cross-linking and curing of the elastomeric material are carried out.

[0007] The tool can be heated here, so that the heat energy transferred from the tool to the blank supports the vulcanization process.

[0008] It has been proven that manufacturing time can be reduced by up to 10 times using the method according to the invention, especially when the valve armature has a small size ranging from a few millimeters to a few centimeters.

[0009] The valve lift of the finished solenoid valve can be, for example, about 0.4 mm.

[0010] The blank is, for example, a solid cylinder, especially a round cylinder, with a size of about 8 mm to 20 mm, i.e. a cylinder without an initial through hole.

[0011] Magnetic metals, such as stainless steel 1.4113, can be used as materials.

[0012] The armature body is preferably a single piece, so the entire valve armature consists of only two parts: the armature body and the elastomeric seal.

[0013] Under normal circumstances, apart from the cold forming step and the insertion, vulcanization and forming of the elastomeric seal if necessary, no other processing steps are required to complete the valve armature.

[0014] Preferably, the blank is upset along the longitudinal direction of the valve armature during the cold forming process, wherein the length of the armature body is set to a predetermined final length dimension. In this case, it is possible to comply with a tolerance of about 0.15 mm. There is no final cutting or removal process for length adaptation.

[0015] Upsetting can be performed through multiple forming steps or at any suitable point in time during cold forming, within a single forming step. For example, it can be the penultimate or final forming step.

[0016] The adhesion of the elastomeric seal in the blind hole of the armature body can be enhanced by creating a protrusion forming a side recess on the inner circumferential side of the blind hole during the molding process. The elastomeric seal extends axially on both sides of this protrusion, thus reliably preventing axial movement of the elastomeric seal. In particular, it eliminates the need to introduce an adhesive between the inner circumferential side and the elastomeric seal, further reducing manufacturing time.

[0017] For example, a blind hole can be designed such that about one-third of the elastomeric material filling the blind hole is located in a lateral recess.

[0018] From a manufacturing perspective, it is advantageous when the protrusion extends in a circumferential direction.

[0019] The terms axial direction, circumferential direction, and radial direction are always related to the longitudinal direction of the valve armature.

[0020] To create the lateral concavity, for example in the first step, a material segment adjacent to the inner circumferential surface of the blind hole is spaced apart on its end face by creating a groove using a first tool that is linearly movable in the axial direction. In the second step, the material segment is deformed radially inward and simultaneously axially toward the bottom of the blind hole using a second tool that is linearly movable in the axial direction, thereby forming a protrusion that circumferentially surrounds and radially protrudes inward. Essentially, the material segment is radially folded inward by the second tool toward the bottom of the blind hole.

[0021] During the forming process, a second tool can be placed against the inner circumferential side of the blind hole, particularly against the radially inner side of the protrusion, in order to define the shape and size of the blind hole in this area.

[0022] Preferably, the second tool has a section located radially inside the protrusion and extending axially into the blind hole, which participates in the forming of the protrusion. During the movement of the second tool, the edge at the radial tip of the protrusion is rounded and, arguably, deburred by the second tool.

[0023] The raised radial tip usually forms the blind hole region with the smallest diameter.

[0024] The section of the second tool that extends into the blind hole is preferably rounded into the adjacent section, such that the protrusion at its radial tip includes a rounded edge in the transition between the end face section immediately surrounding the blind hole and the blind hole. This rounded edge prevents strong forces acting on the elastomeric seal in the minimum diameter region of the blind hole and the corresponding maximum radial extension of the protrusion.

[0025] The protrusions are axially spaced apart, especially from the axial ends of the inner circumferential side of the blind hole.

[0026] The elastomeric seal may have a disc-shaped section in front of the protrusion along the axial direction. This disc-shaped section laterally protrudes beyond the blind hole in the region of the protrusion, and this disc-shaped section constitutes the end-side end of the elastomeric seal. This improves the form-locking, gapless retention of the elastomeric seal in the blind hole. The elastomeric seal is here positioned adjacent to the end wall section that surrounds the blind hole.

[0027] If the valve is closed, only the disc-shaped section of the elastomeric seal rests against the valve seat. However, the valve seat-side end of the disc-shaped section is preferably at the same axial height as the valve seat-side end face. However, this valve seat-side end face is radially further away from the valve seat than the disc-shaped section.

[0028] To accommodate the disc-shaped section, the end face of the valve body is deepened circumferentially in the end face section that extends directly around the blind hole.

[0029] The introduction of the elastomeric seal into the blind bore is carried out, for example, by the following steps: To vulcanize the elastomeric seal, the armature and elastomeric material are heated. The elastomeric material is divided into portions and filled into the blind bore, particularly up to the axial rearward side of the recess. The end-side sections of the elastomeric seal are shaped to their final form, particularly as disc-shaped sections. If necessary, the elastomeric material is vulcanized to its final hardness by an additional heat supply. Simultaneously, the elastomeric seal is secured in the blind bore.

[0030] The introduction of elastomer materials can be achieved, for example, through injection molding, transfer molding, or compression molding.

[0031] It is possible to provide a suitable crosslinking agent for the elastomer material in advance, or to select an elastomer material that can be purely heat-cured.

[0032] Preferably, the armature body is fully formed before the elastomeric seal is introduced into the blind hole.

[0033] It is possible that during cold forming, a flattened portion is produced on the circumferential side surface of the armature body, extending parallel to the longitudinal axis of the valve armature, which improves airflow around the valve armature.

[0034] Furthermore, in one of the cold forming steps, a lateral flange can be formed on the end side configured for the blind hole, i.e., on the valve seat side end side of the armature body. This lateral flange can provide a contact surface for the compression spring used to preload the valve armature to its initial preloaded state.

[0035] The complete manufacturing process of the valve armature can be performed, for example, as follows: First, the blind hole, and, if necessary, the side beveled portion and the lateral flange are introduced into a cylindrical blank through one or more cold forming steps. Then, in a further cold forming step, the material segment for the protrusion is divided, which is then formed into a radial protrusion in a further cold forming step. In one or more of these cold forming steps, or in a separate cold forming step, the armature body is upset to its final length dimension. Finally, the elastomeric material for the elastomeric seal is introduced and formed into a disc-shaped segment of the elastomeric seal. In addition to the described manufacturing steps, further manufacturing steps, particularly the surface finishing of the blind hole or the armature body, can be omitted.

[0036] The solenoid valve, particularly the armature manufactured by the above method, has a blind hole at the valve seat end, in which an elastomeric seal is vulcanized. In this way, the elastomeric seal is firmly fixed in the armature body with the blind hole, which, for example, results in better resistance of the solenoid valve when operating at higher temperatures.

[0037] The valve seat and the valve seat side work together to close the valve in its closed position and interrupt the fluid flow.

[0038] A radially inward protrusion is specially constructed on the inner circumferential side of the blind hole, and a side recess that axially enters into the blind hole is constructed behind the protrusion, and the protrusion fixes the elastomeric seal.

[0039] The protrusion is preferably configured to be axially spaced from the valve seat side face of the valve armature.

[0040] On the axis of the valve armature, a side-cut portion may be provided on the circumferential side surface, which extends parallel to the longitudinal axis of the valve armature and is used to improve the airflow around the valve armature.

[0041] In a solenoid valve having the aforementioned armature and a valve body with a valve seat, an elastomeric seal is positioned opposite the valve seat and can seal against the valve seat when the solenoid valve is in its closed position.

[0042] The valve armature may have a radial flange on the valve seat side end face, which typically corresponds to the armature body of the valve armature. A compression spring rests against this radial flange, preloading the valve armature into an initial state. This initial state can be either an open or closed position.

[0043] Preferably, a protrusion forming a lateral recess exists on the inner circumferential side of the blind orifice, and the valve seat is located radially inside the cross-section formed by the protrusion in the axial direction. With this geometry, pressure is applied to the elastomeric seal fixed in the blind orifice in the radially inner region of the protrusion, resulting in a better fit of the elastomeric seal in the blind orifice and a more uniform deformation of the elastomeric seal when the valve is closed.

[0044] By using a cold forming process to manufacture the armature body of the valve armature and to vulcanize the elastomeric seal into the blind hole of the armature body, rapid and high-precision manufacturing of the valve armature can be achieved. In particular, the final length dimension of the valve armature can be achieved with very low tolerances through upsetting during cold forming. Furthermore, it is possible to fix the elastomeric seal into the blind hole during vulcanization via a side recess also produced during cold forming. Attached Figure Description

[0045] The invention will now be described in more detail with reference to the embodiments in the accompanying drawings. In the drawings:

[0046] Figure 1 A schematic partial cross-sectional view of a solenoid valve having an armature according to the invention is shown, the armature being manufactured by the method according to the invention;

[0047] Figure 2 It shows Figure 1 Detailed view;

[0048] Figure 3 A schematic perspective view of the valve armature according to the present invention is shown;

[0049] Figure 4 It shows the use of Figure 3 A schematic perspective view of the blank of the armature body of the valve armature;

[0050] Figure 5 and 6 A schematic diagram of the tools and forming steps according to the method of the present invention is shown;

[0051] Figure 7 It shows Figure 6 Variations in tools and molding steps;

[0052] Figure 8 A schematic cross-sectional view of the valve armature according to the invention before the vulcanization of the elastomeric seal is shown. Detailed Implementation

[0053] Figure 1 A solenoid valve 10, particularly a lift-type armature valve, is shown, which includes a valve armature 12 that is linearly movable along an axial direction A, and which is movable between an open position and a closed position by a known magnetic actuator (not shown in detail).

[0054] In the open position, which also corresponds to the open position of the solenoid valve 10, the valve armature 12 is lifted by the valve seat 14 of the valve body 16, while in the closed position, which also corresponds to the closed position of the solenoid valve 10, the valve armature 12 is placed on the valve seat 14.

[0055] The axial direction A corresponds to the longitudinal direction of the valve armature 12 and is also equivalent to it in the following text.

[0056] The valve armature 12 here includes a rigid armature body 18 and an elastomeric seal 20, which is securely and permanently fixed to the armature body 18.

[0057] In the closed position, the elastomeric seal 20 makes sealing contact with the valve seat 14 and interrupts the flow of fluid through the solenoid valve 10.

[0058] A blind hole 22 is constructed in the armature body 18, which is radially surrounded on the end side 24 of the valve seat side of the armature body 18 by an annular valve seat side end face 26. The blind hole 22 has a bottom 28 that retracts axially into the armature body 18.

[0059] The elastomeric seal 20 is vulcanized into the blind hole 22 and thus adheres to the inner circumferential side 30 of the blind hole 22 (see, for example). Figure 2 ).

[0060] In the example shown, the elastomeric seal 20 fills the blind hole 22 up to the bottom 28.

[0061] A circumferentially surrounding protrusion 32 is provided, which retracts relative to the end face 26 in the axial direction A toward the bottom 28 of the blind hole 22. The protrusion 32 projects radially from the inner circumferential side 30 into the interior of the blind hole 22 and thus forms a lateral recess that enters axially into the blind hole 22. An elastomeric seal 20 extends axially on both sides of the protrusion 32, such that the protrusion 32 additionally secures the elastomeric seal 20.

[0062] The protrusion 32 is axially spaced from the end face 26 of the armature body 18, wherein the end face 26 is deepened circumferentially in the end face section 70 directly around the blind hole 22.

[0063] At the valve seat end, a disc-shaped section 34 is formed on the elastomeric seal 20, which protrudes in the radial direction r beyond the protrusion 32 and also beyond the valve seat 14. In the axial view, the valve seat 14 is therefore located radially inside the cross section formed by the protrusion 32.

[0064] The disc-shaped section 34 constitutes the end side of the elastomeric seal 20.

[0065] In this example, a plurality of flattened portions 38 are provided on the circumferential side surface 35 of the shaft 36 of the armature body 18 (see Figure 3 These flattened portions 38 extend along the axial direction A and are therefore parallel to the longitudinal axis 12 of the valve armature. These flattened portions 38 are used to improve airflow around the valve armature 12.

[0066] Furthermore, the armature 18 here has a radial flange 40 on its end side 24, which rotates into the end face 26 on the valve seat side and forms a contact surface 42 for compressing the spring 44 on the circumferential side surface 35 on the opposite side of the end face 26 (see Figure 1 and 2 ).

[0067] To manufacture the valve armature 12, firstly... Figure 4 The blank 46, schematically shown, made of a suitable magnetic metal such as stainless steel 1.4113, is formed using multiple steps in a cold forming process. Typically, the order of the various forming steps is determined by those skilled in the art.

[0068] In this example, blank 46 is cylindrical and solid. However, it could certainly have other suitable shapes.

[0069] In one or more forming steps, blind hole 22, flattened portion 38 and radial flange 40 are formed on blank 46 (not shown).

[0070] After constructing blind hole 22, proceed as follows Figure 5 and 6 The two additional forming steps shown involve creating protrusions 32 that form the lateral recesses in the blind hole 22.

[0071] At this point, the blank 46 is housed in an external tool 48, which was previously used for shaping the circumferential side surface 35 and for constructing the radial flange 40. The external tool 48 supports the circumferential side surface 35 and prevents the material of the blank 46 from extending beyond the already formed circumferential side surface 35 in the radial direction r.

[0072] exist Figure 5In the first step shown, a first tool 50, which is linearly movable in the axial direction A, is moved toward the bottom 28 of the blind hole 22, thereby separating and partially separating the material segment 52 on the end face 26 from the radially outer adjacent segment of the end face 26 by creating a groove 54. For this purpose, the first tool 50 has an axially oriented wedge-shaped segment 55, which is pressed into the end face 26 and creates the groove 54.

[0073] exist Figure 6 In the second step shown, the first tool 50 is replaced with a second tool 56, which is also linearly movable along the axial direction A. The second tool 56 is used to deform the material segment 52 radially inward and simultaneously axially toward the bottom 28 of the blind hole 22, thereby creating a protrusion 32.

[0074] It can be said that the material section 52 is folded in the axial direction A, wherein the groove 54 is flattened or completely removed by the second tool 56. For this purpose, the second tool 56 has a stepped section 58 that protrudes axially beyond the section 60 that rests flat against the end side 24. The faces of both sections 58 and 60 pointing toward the blank 46 are oriented perpendicular to the axial direction A.

[0075] This step also creates the valve seat side end face 26. An annular, deeply recessed end face section 70 is created by folding the material.

[0076] The protrusion 32 protrudes radially inward and extends circumferentially.

[0077] Due to the movement path of the second tool 56 in the axial direction A, the protrusion 32 is spaced apart from the end face 26.

[0078] The movement directions of the first and second tools 50 and 56 are in Figure 5 and 6 The arrows represent the numbers.

[0079] Figure 7 A variation of the second tool 56' is shown. Here, another segment 59 is connected radially inward to segment 58, the shape of which corresponds to the desired inner cross-section of protrusion 32.

[0080] Section 59 protrudes axially beyond section 58 and extends slightly more into blind hole 22 than the expected axial length of protrusion 32.

[0081] The transition 61 from section 59 to section 58 is designed to be rounded with a suitable radius, so that the area of ​​the minimum diameter of the opening 72 of the blind hole 22 defining the transition from end face section 70 to protrusion 32, i.e., the area of ​​the minimum diameter of the opening 72 of the blind hole 22 at the radial tip 63 of protrusion 32, obtains a rounded edge (see also...). Figure 8(The dotted line in the diagram). Therefore, the radius should be chosen to be large enough to prevent undesirable large shear forces from acting on the elastomeric seal 20.

[0082] Following these steps, a final forming step is performed, in which the blank 46 is upset along the axial direction A to the predetermined final axial length dimension l for the armature body 18. In this step, the end face 26 also obtains its final shape.

[0083] In this example, this upsetting step completes the forming of the armature body 18.

[0084] The upsetting step can also be performed at other points during cold forming. It is also possible to distribute the upsetting across multiple forming steps, particularly those that form other sections of the blank 46.

[0085] exist Figure 8 The completed blind hole 22 is shown in the example.

[0086] The side recess created by the protrusion 32 is designed such that about one-third of the volume of the blind hole 22 and therefore one-third of the elastomeric material filling the blind hole 22 is located in the side recess.

[0087] The cross-section of the blind hole 22 and, if necessary, the cross-section of the segment 59 of the tool 56' are chosen to be circular. However, other cross-sectional shapes are also possible.

[0088] The possible dimensions of the blind hole 22 are a minimum diameter d of 3.0-3.4 mm, particularly 3.2 mm, at the opening 72 in the end face section 70. min The maximum diameter d is 4.5-5.0mm, especially 4.7mm. max When the depth h of the blind hole 22 from the end face 26 to the bottom 28 is about 2.0-2.7 mm, especially 2.6 mm, the maximum diameter just reaches above the bottom 28 of the blind hole 22.

[0089] This results in the area at the opening 72 of the end face section 70 being relatively smaller than the annular area in the lateral concave region (due to...). Figure 8 The area ratio (shown by the dashed line in the image) is 4.6, or the area ratio between the smallest and largest areas is between 0.44 and 0.46.

[0090] The vulcanization of the elastomeric seal 20 is carried out here by the following steps. The armature body 18 is heated, for example by using a heatable tool such as an external tool 48. Suitable elastomeric material is divided into portions and filled into the blind hole 22 up to the axial rearward side of the recess formed by the protrusion 32.

[0091] The valve seat-side section of the elastomeric seal 20 is shaped to its final form, here as a disc-shaped section 34. In this example, the radially outer edge of the disc-shaped section 34 and the section of the inner circumferential side 30 of the blind hole 22 that abuts the valve seat-side end face 26 are maintained at a distance in the radial direction r (see [reference]). Figure 2 and 3 ).

[0092] The heat required for the vulcanization process is supplied by a heatable tool, which hardens the material of the elastomeric seal 20 to its final hardness while still maintaining the necessary elasticity.

[0093] Because the elastomeric seal 20 surrounds the protrusion 32 on both sides in the axial direction A, the elastomeric seal 20 is secured in the blind hole 22. No special pretreatment of the inner circumferential side 30 or, for example, application of an adhesion promoter is required. The elastomeric seal 20 thus also extends, in particular, past the rounded edge at the tip 63 of the protrusion 32.

[0094] In this example, the end face of the disc-shaped section 34 of the elastomeric seal 20 does not protrude beyond the end face 26 of the valve seat side in the axial direction A.

[0095] For determining the effective length of the gap between the valve armature 12 and the valve seat 14, the length from the end facing away from the valve seat 14 to the front side of the elastomeric seal 20 is crucial. In this regard, the length of the valve body 16 from the end facing away from the valve seat 14 to the end face section 70 formed during the forging process is important.

Claims

1. A method for manufacturing a valve armature (12) for a solenoid valve (10), the valve armature having an armature body (18) and an elastomeric seal (20) fastened to the armature body, the method comprising the following steps: - During the cold forming process, the cylindrical blank (46) is formed to the final axial length dimension (l) of the armature body (18), wherein, A blind hole (22) is formed at one end of the blank (46), and a valve seat side end face (26) surrounding the blind hole (22) is formed, wherein, during forming, a protrusion (32) constituting a side recess is formed on the inner circumferential side (30) of the blind hole (22). In order to form the side recess, in a first step, a material segment (52) adjacent to the inner circumferential side (30) and a segment adjacent to the material segment radially externally are separated on the end face (26) by forming a groove (54) using a first tool (50) capable of linear movement in the axial direction (A), and in a second step, the material segment (52) is deformed radially inward and simultaneously axially toward the bottom (28) of the blind hole (22) using a second tool (56) capable of linear movement in the axial direction (A), thereby forming the protrusion (32), which surrounds circumferentially and protrudes radially inward. - The elastomeric seal (20) is vulcanized on the inner circumferential side (30) of the blind hole (22).

2. The method according to claim 1, characterized in that, During the cold forming process, the blank (46) is upsetting along the longitudinal direction (A) of the valve armature (12), wherein the length of the armature body (18) is set to a predetermined final length dimension (l).

3. The method according to claim 1, characterized in that, The second tool (56') has a section (59) located radially inside the protrusion (32) and extending axially into the blind hole (22), which participates in the shaping of the protrusion (32) and rounds the edge at the radial tip (63) of the protrusion (32) during the movement of the second tool (56').

4. The method according to claim 1 or claim 3, characterized in that, The elastomeric seal (20) has a disc-shaped section (34) in front of the protrusion (32) along the axial direction (A), the disc-shaped section protruding laterally beyond the blind hole (22) in the region of the protrusion (32) and forming the end end of the elastomeric seal (20).

5. The method according to claim 1 or 2, characterized in that, In order to vulcanize the elastomeric seal, the armature (18) and the elastomeric material are heated, the elastomeric material is divided into parts and filled into blind holes (22), the end section of the elastomeric seal (20) is shaped to its final shape, and the elastomeric material is vulcanized to its final hardness.

6. The method according to claim 1 or 2, characterized in that, During cold forming, a side-cut portion (38) extending parallel to the longitudinal axis (A) of the valve armature (12) is formed on the circumferential side surface (35) of the armature body (18).

7. The method according to claim 1 or 2, characterized in that, A lateral flange (40) is formed on the end side (24) of the blind hole (22) by cold forming.

8. An armature of a solenoid valve, said armature being manufactured by the method according to any one of the preceding claims, wherein, The valve armature (12) has a blind hole (22) at the valve seat side end, and the elastomeric seal (20) is vulcanized in the blind hole.

9. The valve armature according to claim 8, characterized in that, A radially inwardly protruding protrusion (32) is constructed on the inner circumferential side (30) of the blind hole (22), and a lateral recess is constructed behind the protrusion and axially enters into the blind hole (22), and the protrusion fixes the elastomeric seal (20).

10. The valve armature according to claim 9, characterized in that, The protrusion (32) is configured to be axially spaced from the valve seat side end face (26) of the valve armature (12).

11. A solenoid valve having a valve armature according to any one of claims 8 to 10 and a valve body (16), the valve body having a valve seat (14), wherein, The elastomeric seal (20) is opposite to the valve seat (14) and can make sealing contact with the valve seat.

12. The solenoid valve according to claim 11, characterized in that, The valve armature (12) has a radial flange (40) on its valve seat side end (24), and a compression spring (44) rests against the radial flange, the compression spring preloading the valve armature (12) to the initial state.

13. The solenoid valve according to claim 11 or 12, characterized in that, There is a protrusion (32) forming a lateral recess on the inner circumferential side (30) of the blind hole (22), and the valve seat (14) is located radially inside the cross section formed by the protrusion (32) in the axial view.

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