Electrically controllable solenoid valve

Abstract

To improve upon the shortcomings of conventional structures and to miniaturize solenoid valves. [Solution] A solenoid valve for open-loop and / or closed-loop control of a pressure medium connection in a hydraulic unit of a vehicle brake system has a valve insert (12) comprising a lower part (14) including a control section (22) and an upper part (16) for guiding a tappet (24), wherein the lower part (14) has an end (14a) introduced into a lower part housing (16a) of the upper part (16), and this end (14a) has at least one cavity (44) that opens toward the upper part (16), and this cavity radially penetrates the wall of the lower part (14).

Description

[[Technical Field]]

[0001] The present invention belongs to the technical field of electronically slip-controllable vehicle brake devices, and relates to an electrically controllable solenoid valve having the features of the preamble of claim 1, which is used for releasing or cutting off a pressure medium connection in a hydraulic unit of such a vehicle brake device. [[Background Art]]

[0002] Many such solenoid valves are arranged on the housing block of the hydraulic unit together with a likewise electrically controllable motor of the brake pressure generator, and are supplied with electrical energy as required by an electronic control unit in dependence on detected sensor signals.

[0003] The solenoid valve according to the present invention is preferably provided for controlling the pressure medium connection between the master brake cylinder of the brake circuit of a vehicle brake device and the wheel brake. In normal operation, the solenoid valve cuts off this pressure medium connection, thereby disconnecting the driver from the wheel brake. In fault operation, the solenoid valve releases this pressure medium connection, so that the brake pressure of the wheel brake can be increased by the driver's muscular force, and the vehicle can be braked even if an electrical fault exists.

[0004] Electrically controllable solenoid valves with the features of the premise of claim 1 are well known from the prior art. In this regard, please refer to the disclosure of Patent Document 1 as an example. In the solenoid valve disclosed herein, the valve housing or valve insert is designed as a multi-component (mehrteilig) for cost reasons, and therefore includes an upper and a lower component. Both housing components are formed in a hollow cylindrical shape and partially overlap longitudinally at extensions facing each other. A first extension is formed in the upper component and engages with a housing in a second extension of the lower component. In the upper component, a tappet having a closure body of the solenoid valve at one end is slidably guided. In the lower component, a control section of the solenoid valve controlled by this closure body is disposed.

[0005] To achieve a pressure medium connection between a first pressure medium connection located on the end face of the valve insert away from the armature and a second pressure medium connection located around the valve insert, the upper component is provided with a groove-like recess (Ausformung) downstream of the control cross-section. This groove-like recess is divided into an axial groove portion in the axial overlap between the upper and lower components, or in the region of the existing pressurized connection (Pressverbindung), and a radial groove portion through which the axial groove portion is connected at one end. The radial groove portion is located over the region where the upper and lower components overlap each other when viewed longitudinally in the solenoid valve, and therefore prevents the possibility of shortening the axial design length of the solenoid valve.

[0006] The reasoning behind moving the radial groove portion lower on the upper component is to reduce the cross-section of the valve insert in the area where the solenoid valve flange is formed and the solenoid valve is crimped to the housing block. As a result, the resulting radial crimping force may not be absorbed or properly guided to the housing block.

[0007] Furthermore, shifting the radial groove portion further downwards could alter the cross-sectional area of ​​the valve insert, potentially affecting the magnetic transfer (magnetischer Uebergang) between the upper and lower components, and reducing the magnetic force available to the magnetic circuit.

[0008] Furthermore, the radial groove portion, which has been moved further down in the upper component, consequently deflects the flow within the valve space, thereby increasing the flow resistance of the solenoid valve. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] German Patent Application Publication No. 102018219955 Specification [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] Therefore, the object of the present invention is to provide a solenoid valve that avoids or improves upon the aforementioned drawbacks. [Means for solving the problem]

[0011] In the solenoid valve according to the present invention, the lower component is connected to the upper component by an end that can be introduced into the lower component housing of the assigned upper component. This end has at least one cavity that opens toward the upper component, and this cavity penetrates the wall of the lower component radially. The cavity is part of the pressure medium connection between the first pressure medium connection and the second pressure medium connection of the solenoid valve and provides the following advantages: By placing a void in the lower component, this void lies on the same plane as the region of the valve insert where the upper and lower components are joined to each other. This makes it possible to shorten the axial design length of the solenoid valve, especially below the crimp flange (Verstemmfransch). Furthermore, the first and second pressure medium connections of the solenoid valve are brought closer to each other in the axial direction, shortening the distance over which the pressure medium flows through the valve space of the solenoid valve. Combined with the reduced degree of deflection of the pressure medium flow in this case, the flow resistance of the solenoid valve according to the present invention is reduced. • The cross-section of the upper component in the crimped flange region does not need to have a channel for guiding the pressure medium, and therefore the shape is stable. A large crimping force can be applied to fix the solenoid valve to the housing block, or the resulting crimping force can be better guided to the housing block via the valve insert. • Because the upper and lower components have a larger common contact surface with each other, the influence of the channel guiding the pressure medium on the magnetic circuit is reduced.

[0012] Other advantages or advantageous forms of the present invention will become apparent from the dependent claims or the following description. [Brief explanation of the drawing]

[0013] [Figure 1] This is a longitudinal cross-sectional view of a valve assembly of an electrically controllable solenoid valve formed according to the present invention. This valve assembly is housed in the valve housing portion of a housing block, and Figure 1 shows the area surrounding this valve housing portion of the housing block. [Figure 2] This is a perspective view of the lower component of the solenoid valve according to the present invention as a single component, shown in a direction that views the end face of the lower component facing the upper component. [Modes for carrying out the invention]

[0014] Exemplary embodiments of the present invention are shown in the drawings and described in detail below.

[0015] Therefore, the drawings include two figures in which the same reference numerals are used for corresponding features.

[0016] The valve assembly (10) shown in Figure 1 is depicted without the electromagnetic coil for simplicity. An annular electromagnetic coil, not shown, can be mounted on this valve assembly (10), which is assumed to surround a so-called valve dome that protrudes beyond the outer surface of the housing block (40). Together, the valve assembly (10) and the electromagnetic coil form the solenoid valve that forms the basis of the present invention.

[0017] The illustrated valve assembly (10) is formed of multiple parts and comprises a valve housing or valve insert (12) consisting of a lower part (14) and an upper part (16). The upper and lower parts are each formed in a hollow cylindrical or sleeve shape and are coaxially inserted into each other. According to the present invention, the lower part (14) has an end (14a) therefor, which is press-fitted into a lower part housing (16a) formed in the upper part (16), thereby creating a force-coupled / geometric-coupled connection between the upper part (16) and the lower part (14). In the joined state, the upper part (16) and the lower part (14) surround a consistent cylindrical valve space (18) by their inner diameter, which is constant over a long axial distance and expands in diameter by two right-angle steps at the open end on the end face side of the lower part (14). A cup-shaped valve body (20) is housed within the valve space (18), which is pre-positioned at the open end of the lower component (14) by its bottom (20a) and is firmly fixed in the minimum diameter region of the valve space (18), for example, using a pressurized connection. A through-opening is formed at the center of the bottom of the valve body (20), which determines the control cross section (22) of the solenoid valve. A pin-shaped closing member (24a) is provided to control this control cross section, which is formed at the end of the tappet (24) on the lower component (14) side. The tappet (24) is also guided by its peripheral wall to slide axially within the upper component (16) of the valve insert (12).

[0018] The transition from the closing member (24a) to the tappet (24) forms a circumferentially extending ring shoulder (24b), which is for a return element (26) in the form of a coil spring of the valve assembly (10), supporting the first of the two ends of the coil spring. The second end, located opposite this, causes the coil spring to abut against the bottom (20a) of the valve body (20). The return element (26) or coil spring is centered on the closing member (24a) and surrounds the control section (22) of the valve assembly (10) formed on the valve body (20). The function of the return element (26) is to lift the closing member (24a) away from the control section (22) when the solenoid valve is not electrically actuated, thereby opening the control section (22) and allowing the pressure medium to flow through the valve space (18) or the control section (22). In this case, the pressure medium flows around the return element (26).

[0019] The pressure medium flows into the valve space (18) at the first pressure medium connection (28) and flows out of the valve space (18) again through the second pressure medium connection (30). Both of these pressure medium connections are located on the lower part (14) of the valve insert (12) in this invention, with the first pressure medium connection (28) located at the open end on the end face side of the lower part, while the second pressure medium connection is located around the end of the lower part (14) closer to the upper part (16). Pressure medium channels (42a; 42b) of the housing block (40) are assigned to the pressure medium connections (28; 30).

[0020] To prevent foreign matter contained in the pressure medium from entering the valve space (18) or being pushed from the valve space (18) into the downstream pressure medium circuit, filter elements (32a, b) are assigned to the pressure medium connection section (28; 30). The first filter element (32a) is formed as a flat filter and is press-fitted into one of the diameter steps (Durchmesserstufe) at the front end of the valve insert (12). In contrast, the second filter element is formed in a sleeve shape and is fitted to the outside of the lower part (14) of the valve insert (12) under radial bias.

[0021] An electromagnetic armature (34) is provided for actuating the tappet (24). The electromagnetic armature is arranged on the outer surface of the valve insert (12) on the upper part (16) side, and rests via its armature end face on the end face of the tappet (24) on the side remote from the closing member. The electromagnetic armature (34) is arranged axially movably inside a valve capsule (36) closed on one side in the shape of a domed roof, and the valve capsule is attached with its open end to the outer circumference of the upper part (16) of the valve insert (12), in this exemplary embodiment exemplarily by means of a circumferentially extending welded joint.

[0022] The upper part (16) of the valve insert (12) has a multi-stepped outer contour, and is divided into a cylindrical shaft (16b) to which the valve capsule (36) is attached, a transition portion adjacent axially thereto to the larger outer dimension of the valve insert (12), and a circumferentially extending crimping flange (16c) at the end on the lower part (14) side. This crimping flange (16c) is located at the height of the lower part receiving portion (16a) formed in the upper part (16), whereby a substantially constant wall cross-section of the upper part (16) is achieved.

[0023] Furthermore, in order to fix the valve assembly (10) to the housing block (40) of the hydraulic unit within the assigned valve receiving portion (38), the caulking flange (16c) protrudes radially outward from the valve insert (12). Furthermore, the valve assembly (10) is introduced into the valve receiving portion (38) from the outside until the caulking flange (16c) abuts circumferentially against the shoulder (38a) formed by the valve receiving portion (38). Subsequently, by an embossing or caulking process, material is deformed from the periphery of the valve receiving portion (38) of the housing block (40) into the interior of this valve receiving portion (38), and the deformed material covers the caulking flange (16c) of the valve body (20) at least in a segment-partial (segmentabschnittsweise) manner, whereby the valve assembly is fixed to the housing block (40). By selecting the position of the shoulder (38a) in the valve receiving portion (38), it is ensured that the pressure medium connections of the solenoid valve contact the assigned pressure medium channels (42a; 42b) in the housing block (40) and are hydraulically sealed to each other.

[0024] A magnetic field is generated by electrical control of a solenoid coil that is not shown in the figure. Based on this magnetic field, a first magnetic pole is formed on the end face of the electromagnetic armature (34) facing the tappet (24), and a second magnetic pole is formed on the end face of the upper part (16) of the valve insert (12) facing the electromagnetic armature (34). The magnetic attractive force acting between the magnetic poles actuates the tappet (24) against the force of the return element (26). In this case, the electromagnetic armature (34) approaches the valve insert (12) leaving a small air gap between the mutually facing end faces, and the closing member (24a) connected to the tappet (24) moves continuously towards the control cross-section (22) until it finally rests on the control cross-section (22) and blocks the connection between the pressure medium channels (42a; 42b).

[0025] Figure 2 shows a perspective view of the lower part (14) of the valve insert (12) as a single component. It can be seen that this lower part (14) is formed as a sleeve-shaped deformation molded part, particularly as a cold-striking part, and has a cavity (44) at the end (14a) that is press-fitted into the upper part (16). In the illustrated exemplary embodiment, three such cavities (44) are exemplary, distributed at the same angular intervals across the end face, in which case the number, arrangement, or dimensions of the cavities (44) of the present invention may not be to scale or may be freely selected according to the application.

[0026] These cavities (44) have open ends facing the upper part (16) and penetrate the wall of the lower part (14) radially. On the outer circumference of the lower part (14), each cavity (44) transitions into a longitudinal groove (45), which extends in the direction of the longitudinal axis L and ends in a conical, circumferentially extending transition section near the center of the lower part (14). At the transition section, the dimensions of the lower part expand to an outer diameter that is somewhat larger than the outer diameter of the lower part (14) in the region of the cavities (44) or longitudinal groove (45). A cylinder section extending to the end face side of the lower part (14) is adjacent to the transition section.

[0027] The upwardly opening cavity (44), together with the outwardly opening longitudinal groove (45) around the lower component (14), forms a channel through which the pressure medium flows out of the valve space (18). Because this channel is outwardly opening, the sleeve-shaped lower component (14) can be fabricated by deformation molding techniques, such as cold impact techniques.

[0028] According to the present invention, when the solenoid valve is assembled, the crimped flange (16c) and the end region (14a) where the lower (14) and upper (16) parts of the valve insert (12) are joined to each other are located at least substantially on the same plane. As a result, on the one hand, secure attachment of the individual parts of the valve insert (12) to each other is obtained, and on the other hand, a firm attachment of the valve assembly (10) to the housing block (40) of the hydraulic unit is obtained. Furthermore, the void (44) and longitudinal groove (45), i.e., the channel for guiding the pressure medium, are formed only in the lower part (14), which makes it possible to shorten the design length of the valve assembly (10), especially in the axial direction. The pressure medium connection parts (28;30) in the solenoid valve according to the present invention are located close to each other in the axial direction, thereby shortening the flow path through which the pressure medium flows through the solenoid valve or valve assembly (10). Furthermore, this flow path does not deflect the flow significantly, thereby reducing the flow resistance of the solenoid valve or the valve assembly (10) of the solenoid valve. The individual components of the valve insert (12) can be manufactured by deformation molding technology, and therefore cost-effectively. In this case, the upper component (16) of the valve assembly (10) does not need to have a channel for guiding the pressure medium, and therefore, based on its stability, the resulting radial crimping force can be effectively guided to the housing block (40).

[0029] Naturally, modifications or advantageous developments of the described exemplary embodiments are conceivable without departing from the scope of protection set forth in the claims. [Explanation of symbols]

[0030] 12 valve inserts 14 Lower part 14a End, end area 16 Upper part 16a Lower component housing 16c crimp flange 18 valve space 20 valve body 22 Control cross section 24 tappets 24a Closing member 24b Ring Shoulder 24a Closing member 26 Return elements 32a Filter element 34 Electromagnetic Armature 44 Blanks 45 Longitudinal grooves, longitudinal channels

Claims

1. In particular, an electrically controllable solenoid valve for open-loop and / or closed-loop control of the connection of a pressure medium in a hydraulic unit of an electronically slip-controllable vehicle brake system, A valve insert (12) having a lower part (14) including a control cross section (22) and an upper part (16) connected to the lower part (14) for guiding a tappet (24), A closing member (24a) coupled to the tappet (24) for controlling the control cross section (22), A solenoid valve comprising: an operable electromagnetic armature (34) that acts on the tappet (24) against the force of a return element (26), The lower part (14) can be introduced into the lower part housing portion (16a) of the upper part (16) that is assigned to it by one end (14a). The end portion (14a) has at least one cavity (44) that opens toward the upper part (16), and the cavity penetrates the wall of the lower part (14) radially. A solenoid valve characterized by the following features.

2. The aforementioned cavity (44) is connected to a longitudinal channel (45) formed on the outer circumference of the lower part (14). The solenoid valve according to claim 1, characterized in that...

3. The lower component housing portion (16a) of the upper component (16) is positioned at the height of the crimping flange (16c) when viewed in the direction of the longitudinal axis (L) of the valve insert (12). The solenoid valve according to claim 1 or 2, characterized in that...

4. The lower part (14) and the upper part (16) can be manufactured by deformation molding technology, and in particular by cold impact technology. A solenoid valve according to any one of claims 1 to 3, characterized in that

5. The lower part (14) and the upper part (16) are connected to each other by shape coupling and / or force coupling, preferably by press-fitting each other. A solenoid valve according to any one of claims 1 to 4, characterized in that

6. A valve body (20) is inserted into the lower part (14), and the control cross section (22) of the solenoid valve is formed on the valve body, and The valve body is supported axially by the first end of the end of the return element (26). A solenoid valve according to any one of claims 1 to 5, characterized in that

7. The tappet (24) has a ring shoulder (24b), and the return element (26) is supported by a second end of the end of the return element on the ring shoulder. A solenoid valve according to any one of claims 1 to 6, characterized in that

8. The return element (26) is positioned between the tappet (24) and the valve body (20) in the valve space (18) through which the pressure medium flows. A solenoid valve according to any one of claims 1 to 7, characterized in that

9. The lower part (14) has an inner diameter that is stepped from the outside to the inside at an end away from the upper part (16), and filter elements (32a) are arranged in a fixed axial direction at the diameter steps. A solenoid valve according to any one of claims 6 to 8, characterized in that

10. The valve body (20) and the filter element (32a) are attached to the lower part (14) by force coupling and / or shape coupling, respectively. The solenoid valve according to claim 9, characterized in that it is the same as described in claim 9.

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