End position sensor for a solenoid valve

Description

[0001] The invention relates to a solenoid valve having the features according to the preamble of claim 1.

[0002] End position sensors in general and solenoid valves with an end position sensor in particular are well known from the state of the art, which is why a separate printed reference is not required at this point.

[0003] End-of-travel sensors are known, for example, from US Pat. Nos. 5,818,223 A and 10,254,103 B2. US Pat. No. 5,818,223 A relates to a non-contact rotary position sensor comprising a permanent magnet and a magnetic sensing element interacting with it. The orientation of the sensing element relative to the magnet's magnetic field allows a conclusion to be drawn about the position of the sensing element. US Pat. No. 10,254,103 B2, however, relates to a magnetic field sensor comprising a permanent magnet, a first magnetic field sensing element, and a second magnetic field sensing element. The two magnetic field sensing elements are geometrically aligned with each other in a particular manner.

[0004] A typical solenoid valve uses an electromagnetic actuator to switch the valve. This allows a distinction to be made between two possible valve positions: the open position and the closed position.

[0005] The closed valve position typically results from the action of a mechanical return element that presses a valve seal against a valve seat. To switch to the open valve position, the electromagnetic actuator must be energized, causing the valve seal to move against the mechanical return force acting on it, thus releasing the valve seat.

[0006] There is an interest in detecting the position assumed by a solenoid valve, i.e., whether the solenoid valve is in the closed or open position. This is achieved by an end-of-travel sensor equipped to sense the position of a solenoid valve.

[0007] According to a first known design, an end position sensor has limit switches.

[0008] These switch depending on the valve position. The disadvantage of this previously known design is that a closed valve construction is not possible, since mechanical access to the valve armature through the limit switches requires a hole in the valve housing. This can lead to leaks even when used as intended. Furthermore, it inevitably results in a less compact design.

[0009] According to another embodiment known from the prior art, the current characteristic resulting from the energization of the electromagnetic drive is evaluated. This enables very precise sensing of the valve position. However, the disadvantage of this prior art design is that the valve position is not determined directly, but only indirectly via the current consumption of the electromagnetic drive. Therefore, there is ultimately no certainty as to whether the valve position presumed based on the current characteristic corresponds to the actual valve position. Furthermore, evaluating the current characteristic requires a sensor that is comparatively complex and therefore expensive.

[0010] EP 1 213 521 B1 discloses a solenoid valve according to the preamble of claim 1.

[0011] Therefore, based on the above, it is TaskThe invention proposes an end position sensor for a solenoid valve which, due to its design, enables reliable detection of a valve position while being easy to handle. Solution To achieve this object, the invention proposes a solenoid valve having the features of claim 1

[0012] The solenoid valve according to the invention has an end-position sensor with a housing that houses a magnetic field transmission device. When the solenoid valve is used as intended, applying a voltage to the solenoid coil of the electromagnetic drive creates a magnetic field that magnetizes the magnetic field transmission device. This newly created magnetic field of the magnetic field transmission device can be detected by the sensor element provided by the control board. Depending on the strength of the magnetic field emanating from the magnetic field transmission device, the position of the solenoid valve can be detected. Advantageously, not only the solenoid valve's end positions but also its intermediate positions can be sensed.

[0013] The control board also features evaluation electronics to evaluate the sensor signal from the sensor element. When used as intended, this electronics outputs an evaluation signal, which can be output as a visual display or an analog signal, for example. The visual display can be provided, for example, by an LED provided by the limit sensor.

[0014] The control board, including the sensor element and evaluation electronics, as well as the magnetic field transmission means, are arranged within the housing volume provided by the housing. Furthermore, the housing volume is filled with a potting compound in which the control board is embedded. This design provides the particular advantage that the control board is protected from external influences, in particular from the ingress of liquids and / or dirt particles or other contaminants, which enables the solenoid valve according to the invention to be used underwater and / or under conditions susceptible to dirt. The solenoid valve according to the invention thus offers a wide range of applications, thus ensuring simplified handling.

[0015] The potting compound also ensures the distribution of heat that is generated during normal operation of the solenoid valve, whereby heat dissipation is possible via the housing in contact with the potting compound.

[0016] Furthermore, compared to position detection using limit switches, no additional spindle with permanent magnets is required, significantly reducing the overall size and allowing for an overall compact design of the solenoid valve according to the invention. Furthermore, the solenoid valve according to the invention has a closed design, so that, unlike an open design, sealing issues do not arise.

[0017] The magnetic field transmission means of the solenoid valve according to the invention acts as a means of amplification for the magnetic field generated during operation of the solenoid valve. Since the magnetic field strength changes depending on the valve position, each valve position can be detected and output using the end position sensor. The detection of the magnetic field generated by the magnetization of the magnetic field transmission means, as provided by the invention, makes it possible to detect even the slightest position changes of the solenoid valve. This allows strokes of less than 2 mm, preferably less than 1 mm, even more preferably less than 0.5 mm, and most preferably up to 0.2 mm to be reliably detected and evaluated.

[0018] The heat dissipation resulting from the potting compound during operation allows the solenoid valve according to the invention to be used in a temperature range between -40°C and 150°C. At the same time, resistance to various environmental influences is ensured, thus providing a wide range of applications for the solenoid valve according to the invention.

[0019] Overall, the design according to the invention proposes a solenoid valve that is easy to handle, enables safe application, offers a compact design, and can also reliably sense even the smallest strokes. The solenoid valve according to the invention is simple in construction and therefore inexpensive to manufacture.

[0020] According to a further feature of the invention, the magnetic field transmission means is designed in the manner of a disc and has an outer contour corresponding to the inner contour of the housing. This configuration of the magnetic field transmission means enables a housing design that is open on one side, since the magnetic field transmission means closes the housing like a lid in the final assembled state. The housing and the magnetic field transmission means rest against each other with their contours, forming contact, which simultaneously ensures a sealing arrangement of the magnetic field transmission means and the housing with respect to the potting compound.

[0021] According to a further feature of the invention, the magnetic field transmission means is securely held by the housing. This ensures a consistent and defined spacing between the magnetic field transmission means and the sensor element provided by the control board. For the secure holding of the magnetic field transmission means by the housing, it can be provided, for example, that the magnetic field transmission means is pressed into the housing.

[0022] According to a further feature of the invention, the magnetic field transmission means rests against a stop on the housing. This ensures precise alignment of the magnetic field transmission means relative to the housing.

[0023] According to a further feature of the invention, the magnetic field transmission means has two through-holes. These serve to fill the remaining volume provided by the housing with potting compound following assembly of the control board and magnetic field transmission means. Potting compound enters the housing interior through one of the two through-holes, and the air displaced thereby can escape from the housing through the second through-hole.

[0024] According to a further feature of the invention, the magnetic field transmission means has an interface for connection to a counter core of the solenoid valve. This allows for easy installation for the intended positioning of the end position sensor on the solenoid valve. Furthermore, a defined position between the counter core and the sensor is ensured, which supports the intended formation of a magnetic field in the magnetic field transmission means.

[0025] According to a further feature of the invention, the interface is a threaded hole. This allows for a replaceable arrangement of the sensor on the solenoid valve, which makes it easy to replace the sensor or the solenoid valve, particularly in the event of a defect. Furthermore, the detachable arrangement of the sensor on the solenoid valve has the advantage that the sensor can be provided as an optional component, thus allowing the user to choose whether to use the solenoid valve with or without a sensor.

[0026] According to a further feature of the invention, the control board rests against a stop on the housing. This ensures secure positioning of the control board relative to the housing. Since the magnetic field transmission means is also positioned in a defined manner relative to the housing, this results in a defined spacing between the control board and the magnetic field transmission means.

[0027] According to a further feature of the invention, the control board is equipped with a signal transmission means. This signal transmission means serves to output and / or forward a signal generated by the evaluation electronics during its intended use.

[0028] According to a further feature of the invention, the signal transmission means is a connector accessible from the outside through a housing opening. When used as intended, a signal transmission cable with a correspondingly designed mating connector can be connected to this connector to establish a communications connection.

[0029] According to a further feature of the invention, the control board rests against the housing-side stop with the connector interposed. Accordingly, the control board is not positioned directly against the housing stop, but rather with the connector interposed. This results in an overall compact design and also ensures that the control board itself has no contact with the inner wall of the housing. This, after the potting compound has been applied, has the advantage that the control board is completely surrounded by the potting compound, thus being embedded in it. This ensures complete protection of the control board against external influences.

[0030] According to a further feature of the invention, the sensor element is provided on the magnetic field transmission means side of the control board. This creates a defined distance between the magnetic field transmission means and the sensor element, with the sensor element being arranged directly opposite the magnetic field transmission means. In the final assembled state, the volume space between the magnetic field transmission means and the sensor element contains only potting compound, which ensures optimized detection of a magnetic field generated by the magnetic field transmission means by the sensor element.

[0031] According to a further feature of the invention, the sensor element is a Hall sensor. This ensures effective, reliable, and reproducible magnetic field detection by the sensor element.

[0032] To assemble the solenoid valve according to the invention, the connector and control board must first be positioned in the housing. The disc-shaped magnetic field transmission means must then be inserted into the housing. In the final assembled state, the housing, which is open on one side, is closed by the magnetic field transmission means like a lid. The remaining volume still accommodated by the housing must then be filled with potting compound. For this purpose, liquid potting compound must be introduced into the housing via one of the two through-holes in the magnetic field transmission means. As soon as the remaining volume provided by the housing and the through-holes in the magnetic field transmission means are completely filled with potting compound, the filling process is complete, and the potting compound can now harden.

[0033] The casting compound is preferably a self-curing plastic material.

[0034] Further features and advantages of the invention will become apparent from the following description based on the figures. These show: Fig. 1 shows a schematic sectional view of a solenoid valve with an end-position sensor arranged thereon according to the invention; Fig. 2 shows a schematic sectional view of the end-position sensor; and Fig. 3 shows a schematic perspective sectional view of the end-position sensor.

[0035] Fig. 1 A schematic sectional view of a solenoid valve 1 according to a typical design is shown. This valve is equipped with an end-position sensor 2. For signal transmission, the end-position sensor 2 is connected to a communication connection 3.

[0036] The solenoid valve 1 has, in a conventional manner, a valve fitting 7 that provides an inlet 8 and an outlet 9. A media flow enters the valve fitting 7 via the inlet 8 in accordance with arrow 10 and is discharged via the outlet 9 when the valve seat 12 is open in accordance with arrow 11.

[0037] The valve seat 12 interacts with a valve seal 13. In the closed position of the valve, as shown in Fig. 1 As shown, the valve seal 13 rests against the valve seat 12 and closes it. In this position of the valve seal 13, the solenoid valve 1 is in the closed position.

[0038] The valve seal 13 is provided by an armature 15 guided in a tube 16.

[0039] Together with the valve seal 13, the armature 15 can be moved with respect to the plane of the drawing Fig. 1 move left or right.

[0040] In accordance with Fig. 1 closed position of the solenoid valve 1, a return spring 14 presses the armature 15 together with the valve seal 13 provided thereby with reference to the plane of the drawing Fig. 1 to the left, thus against the valve seat 12.

[0041] The solenoid valve 1 furthermore has a counter core 17. This is operatively connected to an electromagnetic coil 18, which is supplied with current via a connection 19 during operation. When energized, a magnetic field is created in the counter core 17, whereby the armature 15 is pulled against the force of the return spring 14 towards the counter core 17, and the armature 15 therefore moves with respect to the plane of the drawing. Fig. 1 to the right. As a result, the valve seal 13 detaches from the valve seat 12, opening the valve. With the valve seal 13 in this position, the solenoid valve 1 is therefore in the open position.

[0042] The end position sensor 2 is used to detect the valve position.

[0043] As can be seen particularly from a summary of the Fig. 2 and 3 The end-position sensor 2 has a housing 22. A control board 24 and a magnetic field transmission means 23 are also provided. Both the control board 24 and the magnetic field transmission means 23 are housed in the housing 22 in the final assembled state.

[0044] The magnetic field transmission means 23 is designed in the manner of a disc and closes the housing 22, which is open on one side, in the manner of a lid. For the purpose of precise positioning within the housing 22, the magnetic field transmission means 23 rests against a housing-side stop 30, as can be seen in particular from the illustration according to Fig. 2 results.

[0045] The magnetic field transmission means 23 provides two through holes 31 and 32 and a threaded hole 21.

[0046] The control board in turn has a sensor element 29 and an evaluation electronics 33. The sensor element 29 is provided on the magnetic field transmission side of the control board 24, as can also be seen in particular from the illustration according to Fig. 2 results.

[0047] The control board 24 is further equipped with a signal transmission means in the form of a connector 6. In the final assembled state, this connector is located in a bore 26 provided by a threaded extension 20 of the housing 22. The connector 6 rests against a stop 28 on the housing side and is accessible through a housing opening 27.

[0048] The threaded bore 21 provided by the magnetic field transmission means 23 serves to arrange the end position sensor 2 on the solenoid valve 1, into which a threaded extension 20 of the counter core 17 engages, as can be seen from the illustration according to Fig. 1 results.

[0049] Fig. 1 It can further be seen that a plug 5 ending in a cable 4 is provided for connecting the communication connection 3 to the plug 6, which plug 5 is designed to be compatible with the plug 6.

[0050] The housing volume provided by the housing 22 is filled with a potting compound 25. The control board 24 is embedded in this potting compound 25, as can be seen in particular from the illustration according to Fig. 2The control board 24 is surrounded on all sides by the potting compound 25, thus being arranged within the housing 22 without contact with the housing. This provides reliable protection for the control board 24 from external influences, including liquids, thus making the solenoid valve (1) according to the invention suitable for underwater use.

[0051] The through-holes 31 and 32 provided by the magnetic field transmission means 23 are used to introduce the potting compound 25 into the housing volume space. For the final formation of the end-position sensor, the still-liquid potting compound 25 is introduced into the housing 22 through one through-hole 31 or 32. The air displaced in this process can flow out through the other through-hole 31 or 32. As soon as the housing volume space and the two through-holes 31 and 32 are completely filled with potting compound 25, the filling process is complete, so that the potting compound 25 can then cure.

[0052] The solenoid valve (1) according to the invention functions as follows: When energized, a magnetic field forms in the counter core 17 in a conventional manner. This magnetic field leads to a magnetization of the magnetic field transmission medium 23. A new magnetic field is created, so to speak, which is detected by the sensor element 29. The strength of the magnetic field is a measure of the position of the armature 15. The sensor 2 can therefore detect not only the closed or open position of the solenoid valve 1, but also intermediate positions. Reference symbol

[0053] 1 Solenoid valve 2 End-of-travel sensor 3 Communications connection 4 Cable 5 Connector 6 Connector 7 Valve fitting 8 Inlet 9 Outlet 10 Arrow 11 Arrow 12 Valve seat 13 Valve seal 14 Return spring 15 Armature 16 Tube 17 Counter core 18 Electromagnetic coil 19 Connection 20 Threaded extension 21 Threaded hole 22 Housing 23 Magnetic field transmission medium 24 Control board 25 Potting compound 26 Hole 27 Housing opening 28 Stop 29 Sensor element 30 Stop 31 Through hole 32 Through hole 33 Evaluation electronics

Claims

1. Solenoid valve comprising a valve seat (12) and a valve seal (13) that is provided by an armature (15) guided within a tube (16) and having a solenoid coil (18) and a counter core (17) operatively connected to it, wherein the counter core (17) is configured, to attract the armature (15) together with the valve seal (13) against a force applied by a return spring (14) when the solenoid coil (18) is energized, and comprising an end position sensor (2) with a housing (22), characterized by a control board (24) that provides a sensor element (29) and evaluation electronics (33) and a magnetic field transmission means (23) arranged within the housing (22) and spaced in a defined manner from the control board (24), which magnetic field transmission means (23) has an interface for arrangement on the counter core (17) and is configured upon energization of the solenoid coil (17) to be magnetized by the magnetic field of the counter core (17), wherein the sensor element (29) is configured to detect the magnetic field of the magnetic field transmission means (23) and to detect the position of the solenoid valve (1) depending on the strength of the magnetic field emitted by the magnetic field transmission means (23), wherein, furthermore, the volume space provided by the housing (22) is filled with a potting compound (25) having the control board (24) embedded therein.

2. Solenoid valve according to claim 1, characterized in that the magnetic field transmission means (23) is designed in the manner of a disk and has an outer contour corresponding to the inner contour of the housing (22).

3. Solenoid valve according to claim 1 or 2, characterized in that the magnetic field transmission means (23) is accommodated by the housing (22) in a positionally safe manner.

4. Solenoid valve according to any one of the preceding claims, characterized in that the magnetic field transmission means (23) bears against a housing-side stop (30).

5. Solenoid valve according to any one of the preceding claims, characterized in that the magnetic field transmission means (23) includes two through-holes (31, 32).

6. Solenoid valve according to claim 1, characterized in that the interface is a threaded bore (21).

7. Solenoid valve according to any one of the preceding claims, characterized in that the control board (24) bears against housing-side stop (28).

8. Solenoid valve according to any one of the preceding claims, characterized in that the control board (24) is equipped with a signal transmission means.

9. Solenoid valve according to claim 8, characterized in that the signal transmission means is plug (6) that can be accessed from outside through a housing opening (27).

10. Solenoid valve according to claim 9, characterized in that the control board (24) bears against the housing side stop (28) with the interposition of the plug (6).

11. Solenoid valve according to any one of the preceding claims, characterized in that the sensor element (29) is provided on the side of the magnetic field transmission means by the control board (24).

12. Solenoid valve according to any one of the preceding claims, characterized in that the sensor element (29) is a Hall sensor.