Control unit and actuator with control unit

An electronic control unit (1) or an electric actuator (2), respectively, have a switch-off device (4) which includes at least one reed switch (6, 18, 26) and at least one permanent magnet arranged outside the housing (3) and removable from the housing (3). If the permanent magnet (7) is removed from its position of usage at the housing (3), for example in order to perform maintenance of the electronic control unit (1) or of the actuator (2), respectively, the at least one reed switch (6, 18, 26) is opened, as result of which the supply link (8, 10) between the activating terminal (5) and the supply terminals (9, 11) of the control unit are interrupted in order to switch voltage-carrying functional elements of the control unit (1) and/or of the electric actuator (2) to be currentless and thus to effectively prevent an unwanted spark discharge.

INCORPORATION BY REFERENCE

The following documents are incorporated herein by reference as if fully set forth: German Patent Application No. 102015008276.0, filed Jun. 26, 2015.

BACKGROUND

The invention relates to an electronic control unit, particularly for controlling an actuator, comprising a housing accommodating the electronic control unit, and an activating terminal.

Furthermore, the invention also relates to an electric actuator comprising an electronic control unit, and comprising a housing accommodating the electronic control unit.

Such control units and actuators with control units are known in different embodiments and have been successful. In this context, the actuator to be controlled can be connected or is connected to the activating terminal.

In the case of a maintenance or repair of such a control unit or of such an actuator or for other reasons, it may be necessary to open the housing in which the control unit is arranged. As a result, voltage-conducting parts can be exposed at which a spark discharge can possibly occur. On the one hand, this can represent a risk of injury for a person charged with the maintenance and on the other hand, such spark discharges in environments subject to explosion hazards can lead to explosions.

From DE 10 2008 021 542 A1, a contact and access protection for the high-voltage components of a hybrid vehicle is known. For this purpose, a monitoring device is provided which is fed from the low-voltage system of the vehicle. The monitoring device has electronically controllable circuit breakers which connect the electrical drive to a high-voltage battery. The high-voltage components are monitored by a low-voltage circuit loop, the circuit breakers being opened in the case of an interruption of the circuit loop and the high-voltage thus being separated. The circuit loop is separated, for example, when the engine hood is opened so that no high-voltage is present in the engine space and there is no hazard in the case of maintenance work.

In the case of this circuit, the monitoring device, however, remains permanently supplied with current so that there is still a certain hazard. It is particularly in the case of actuators which are operated in environments subject to explosion hazards that a low voltage can already be sufficient for generating an igniting spark.

SUMMARY

It is thus the object of the invention, on the one hand, to prevent a risk of injury for a person charged with maintenance or repair of the control unit or of the actuator, respectively, and, on the other hand, to avoid an explosion possibly caused by a spark discharge.

In the case of the control unit initially defined, this object is achieved by one or more features of the invention. According to the invention, it is provided particularly for achieving this object that the electronic control unit has a switch-off device, that the switch-off device comprises at least one reed switch and at least one permanent magnet arranged outside the housing and removable from the housing, the at least one reed switch being closed when the at least one permanent magnet is arranged at the housing. The at least one reed switch can be opened by removing the at least one permanent magnet from the housing. A supply link between the activating terminal and a supply terminal of the control unit is established when the reed switch is closed and is interrupted when the reed switch is opened.

The supply terminal is then used for supplying the control unit and/or consumers, appliances or devices which can be connected to it, with power.

It is thus possible that by removing the permanent magnet from the housing, voltage-conducting parts of the electronic control unit can be separated from a power supply. In this manner, a spark discharge can be effectively avoided at these voltage-conducting parts of the control unit when before or on opening the housing, that is to say when there is the risk that the voltage-conducting parts of the control unit come into contact with the environment subject to explosion, the at least one permanent magnet is removed from the housing from its position provided there.

In this arrangement, it is possible that the control unit has at least one energy store connected via a supply link, for example the supply link already mentioned before, to a supply terminal, for example the supply terminal already mentioned before. This energy store is, as a rule, a current store. Furthermore, it can be provided that a supply link, for example the supply link already mentioned before, between an energy store, especially the at least one energy store already mentioned before and a supply terminal, preferably the supply terminal already mentioned before, can be separated with the aid of the switch-off device.

The control unit preferably has at least one link capacitor as energy store. As a rule, a link capacitor is understood to be an electric capacitor in a link circuit of inverters. Its task is the coupling of the energy of a number of electrical power systems to one another on a common voltage level.

When the supply link between this energy store and a supply terminal, via which the energy store, particularly, therefore, the link capacitor, is supplied with energy or with current, respectively, can be separated with the aid of the switch-off device, the energy store or the link capacitor, respectively, can become discharged via this connected consumer as soon as the switch-off device has effected a separation of the supply link. In this manner, it can be avoided that a voltage is present at the energy store, particularly at the link capacitor, of the control unit which could lead to an unwanted spark discharge.

It may be appropriate if the switch-off device comprises at least one relay which can be operated by opening the at least one reed switch in order to effect an interruption of the supply link(s).

An accumulator and/or a battery and/or a power system terminal can be provided and/or formed on the control unit. Whereas the power system terminal of a power supply of a consumer connected to the control unit in operating position, particularly of an actuator, can be provided in normal operation, an accumulator and/or a battery can serve as emergency power supply of the consumer connected to the control unit in operating position.

It may be appropriate in this context if a supply terminal, for example the supply terminal already mentioned before, of the control unit is connected detachably or undetachably to an accumulator, for example the accumulator already mentioned before, and/or to a battery, for example the battery mentioned before, intended for the emergency power supply. Advantageously, the accumulator and/or the battery can then be arranged in the housing of the electronic control unit.

Appropriately, at least one reed switch can be allocated to an accumulator, for example the accumulator already mentioned before, and/or to a battery, particularly the battery already mentioned before, of the control unit. Alternatively or additionally, at least one reed switch can be allocated to a generator, for example the generator already mentioned before. It is of advantage in this context that the generator is reliably deactivatable. Thus, it can be avoided that an unintentional operation of the generator with the housing opened leads to an unwanted discharge at exposed contacts. Preferably, this at least one reed switch can be arranged in such a manner that the at least one reed switch, already mentioned before, of the control unit and the reed switch allocated to the accumulator and/or to the battery can be operated by a permanent magnet. In this way it is possible to ensure that, when a permanent magnet is removed from its position of usage at the housing of the control unit, not only a supply link between the activating connection and a supply terminal is interrupted but also that a supply terminal to the accumulator and/or to the battery can be interrupted. In this way, it is possible to ensure that voltage-carrying elements of the control unit and/or also of a consumer connected to the control unit in the position of usage, particularly of an actuator, are switched to be currentless and are therefore free of voltage.

In an advantageous embodiment, it may be provided that the supply link is designed to be branched with a first supply terminal and a second supply terminal. It is advantageous in this context that a number of energy sources can be provided. In particular, it can be provided in this context that in a first branch, a system connection is designed as the supply terminal and a reed switch is arranged. Thus, the invention enables a control unit to be separated reliably from the system connection when the permanent magnet is removed. In this context, the reed switch can be followed by an energy store, particularly the energy store already mentioned, for example a link capacitor. It is of advantage in this context that charging up of the energy store can be interrupted on removal of the permanent magnet. It is thus possible to achieve that the energy store discharges until the housing is opened. It is particularly advantageous here if the permanent magnet is part of a latching and/or mounting device for mounting at least one housing part on the housing. Additionally, it can be provided in this context that in a second branch, an accumulator, for example the accumulator already mentioned, and/or a battery, for example the battery already mentioned, is connected to the second supply terminal and a further reed switch is arranged. Thus, the accumulator and/or the battery can be separated from the supply terminal on removal of the permanent magnet. The switch-off device thus has two reed switches which follow the respective supply terminals in the manner described. In the second branch, it can be provided that a diode precedes the further reed switch. Thus, a current flow to the accumulator and/or to the battery can be prevented. This is particularly advantageous when the second branch is combined with the first branch behind the energy store already mentioned. Because it is in this manner that it can be prevented that the energy store discharges into the accumulator.

In an embodiment of the invention of particular significance, it may be provided that the at least one permanent magnet is part of a latching and/or mounting device for mounting at least one housing part at the housing of the control unit. In particular, it can be provided that the at least one permanent magnet is arranged in a housing lid of the housing. In this way, it can be ensured that the at least one permanent magnet is removed during an opening of the housing and during a removal of the housing part, particularly of the housing lid, and thus can no longer affect the at least one reed switch. As soon as the at least one permanent magnet is sufficiently far removed from the at least one reed switch, that is to say the effect of the at least one permanent magnet on the at least one reed switch is sufficiently low, the at least one reed switch automatically opens as a result of which the supply link(s) can be separated in the manner described before.

As a rule, a housing lid is used for closing an access opening into the interior of the housing.

Preferably, the at least one permanent magnet can then be formed and/or arranged in or on at least one mounting element, particularly a screw. With this mounting element, a housing part, preferably a housing lid which closes an access opening in the interior of the housing, can be attached to another housing part of the control unit. In this way, it can be ensured that on detaching the at least one mounting element, which may be necessary for opening the housing and for performing maintenance work, the at least one permanent magnet is necessarily removed from its position of usage at the housing and voltage-conducting parts of the control unit and/or of a consumer connected to the control unit, particularly of an actuator, are switched to be currentless, as a result of which an unwanted spark discharge can be effectively avoided.

So that the effect of the at least one permanent magnet on the at least one reed switch is not impaired when the at least one permanent magnet is arranged in its position of usage at the housing of the control unit, it may be appropriate if the housing and/or the at least one mounting element accommodating the at least one permanent magnet consists of a magnetically non-conductive material. In this way, it can be avoided that the magnetic field lines of the at least one permanent magnet extend in the material of the housing or of the mounting element accommodating the at least one permanent magnet and then do not reach the at least one reed switch. A magnetically non-conductive material can be characterized, for example, in that a presence of the material does not or at least not significantly change a course of magnetic field lines.

If the control unit has at least two reed switches connected behind one another, a redundancy of the switch-off device can be achieved. In this way, it can be ensured that the switch-off device functions even if one of the two reed switches should be defective. This is because, in the case of this circuit it is possible that in any event, at least one of the reed switches opens when the permanent magnet is removed from its position of usage at the housing.

Alternatively or additionally, it can also be provided that the control unit has at least two reed switches connected in parallel with one another. In this way, it is possible to achieve that at least one reed switch closes and thus reverses an interruption of the supply link when a permanent magnet is brought into its intended position of usage at the housing of the control unit. An additional improvement of the switch-on or switch-off reliability can be achieved if the control unit has a series circuit of reed switches connected in parallel with one another and/or a parallel circuit of reed switches connected in series.

In order to additionally increase the safety for an operator in the maintenance of the control unit it can be provided that the control unit is configured to detect a switch position of the at least one reed switch of the control unit and/or switch a motor of a drive connectable and/or connected with the control unit, particularly an actuator, to be currentless.

Additionally or as an alternative, the control unit can also be configured for discharging an energy store, for example the energy store already mentioned before. In dependence on a detected switch position of the at least one reed switch, the control unit can deactivate the motor in this way by using corresponding circuits and also actively discharge the energy store designed in particular as link capacitor in order to prevent an unwanted spark discharge and/or an operation of the motor to be avoided during a repair or maintenance.

In the case of the electric actuator defined initially, an electric actuator having the features of the independent patent claim directed towards an actuator is proposed for achieving the said object. In particular, the object mentioned initially is achieved with such an electric actuator by the fact that the electronic control unit is a control unit according to the invention, particularly as described before and/or in accordance with one of the claims directed to a control unit. In this way, both an unwanted spark discharge and a possibly hazardous operation of the motor during a maintenance of the electric actuator or of the electronic control unit of this electric actuator can be avoided. Such an electric actuator is thus suitable to a particular degree also for use in environmental conditions subject to explosion hazards.

Suitably, a motor of the actuator can be switchable to be currentless by removing the at least one permanent magnet, especially due to the fact that a discharging of a or the link capacitor of the control unit can be triggered by removing the at least one permanent magnet.

When using at least two reed switches, it can be provided that the reed switch by means of which discharging of an energy store can be triggered passes out of an effective range of the permanent magnet first during the removal. This can be achieved by a corresponding spatial arrangement. It is of advantage in this context that sufficient time remains for discharging until the complete removal of the permanent magnet.

In this context, the actuator and the control unit can preferably be arranged in a common housing. In this way, it is possible to ensure that in the case of an opening of the housing, the at least one reed switch of the control unit is opened by removal of the at least one permanent magnet from its position of use at the housing as a result of which a supply link in the interior of the housing can be interrupted for switching the voltage-carrying elements of the actuator or of the control unit, respectively, to be currentless.

It can also be particularly advantageous if a removable permanent magnet and an associated reed switch of the switch-off device are provided at a, preferably at each maintenance opening in the housing of the actuator. In this manner, it is possible that each maintenance opening of the actuator is protected with the switch-off device according to the invention so that switching of the voltage-carrying parts of the control unit and/or of the actuator to be currentless is possible independently of which of the possibly several maintenance openings of the housing is utilized.

It should be pointed out that the control unit and/or the actuator and/or a housing of the control unit and/or of the actuator can be designed to be protected against explosions if this is required by the environmental conditions in which the control unit or the electric actuator, respectively, are to be used.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 4show an electronic control unit, designated by1overall, which is connected to the actuator2for controlling an actuator2. The electronic control unit1is arranged in a housing3which is shown in section inFIG. 4.

The electronic control unit1has a switch-off device4for an activating terminal5of the control unit1. The switch-off device4comprises at least one reed switch6and at least one permanent magnet7arranged outside the housing3and removable from the housing3.

The at least one reed switch6is closed when the one permanent magnet7is arranged at the housing3(compareFIG. 4). The reed switch6can be opened by removing the permanent magnet7from its position of usage at the housing. This is carried out in that the magnetic field illustrated by the ellipse E shown in dashed line inFIG. 4is removed by removing the permanent magnet7from the reed switch6so that no sufficiently large magnetic effect can be induced in the latter any longer in order to keep the reed switch6closed.

A supply link8between the activating terminal5and a supply terminal9of the control unit1which is used for the main supply of the actuator2is established or activated with the reed switch6closed. This supply link8can be interrupted by an opening of the reed switch6. Thus, the voltage-carrying functional elements arranged in the control unit1can be switched to be currentless by removing the permanent magnet7in order to avoid a spark discharge which must be absolutely avoided when opening the housing3in an environment subject to explosion hazards.

The control unit1also has an energy store12, connected to the supply terminal9via the supply links8, which is designed as current store. As described, the supply links8between energy store12and the supply terminal9can be separated with the aid of the switch-off device4.

The energy store12shown greatly diagrammatically inFIG. 1is designed as link capacitor13.

As shown inFIGS. 2 and 3, the switch-off device4comprises a relay14which can be operated by opening the reed switch6in order to effect an interruption of the supply links8,10also shown only highly diagrammatically inFIGS. 2 and 3. The reed switch6is connected to a relay driver27which processes the setting signal of the reed switch6and forwards it to the relay14.

According toFIGS. 1 and 4, an accumulator15or a battery15, respectively, and a line terminal16is provided or formed at the control unit1. Via the line terminal16, the supply terminal9of the control unit1can be supplied with current which is necessary for operating the actuator2.

A second supply terminal11of the control unit is connected to the accumulator15. Depending on the exemplary embodiment of the control unit1, this link between the supply terminal11and the accumulator or the battery, respectively,15can be designed to be detachable or also undetachable.

Also for an emergency power supply, a, particularly hand-operated, generator34is provided which is also connected to the supply link10via a supply terminal17of the control unit1and can thus deliver current to the activating terminal5when required.

Overall, the supply link8,10is thus designed to be branched with a first branch35and a second branch36which are brought together in a Y shape at the supply terminal5.

In the first branch35, the line terminal16is formed at the supply terminal9, via which the control unit1can be connected or is connected to a supply system. The first supply terminal9is followed by the aforementioned reed switch6which is followed by an energy store12.

In the second branch36which, in turn, is designed itself to be branched with second supply terminals11,17, diodes37in each case follow the second supply terminals11,17. These diodes37are followed by the further reed switch18by means of which the generator34and the accumulator15(or a battery) can be separated from the supply link8,10.

FIGS. 1 and 4also show that a reed switch18is also allocated to the accumulator15of the control unit1.

This reed switch18allocated to the accumulator15is arranged in such a manner that the reed switch6of the control unit1and the reed switch18allocated to the accumulator15or the battery15, respectively, can be operated by one and the same permanent magnets7.

This becomes particularly clear by the representation according toFIG. 4in which the magnetic field emanating from the permanent magnet7is illustrated by means of the ellipse E shown dashed. On consideration ofFIG. 4it can be seen that both reed switches6and18, with the permanent magnet7arranged in the position of usage, are located at least partially within the ellipse E and thus within the effective range of the permanent magnet7.

If then the permanent magnet7is removed from its position of usage at the housing3, first the reed switch6of the control unit1and then the reed switch18allocated to the accumulator15or the battery15pass out of the effective range of the permanent magnet7, as a result of which first the reed switch6and then the reed switch18are opened in order to interrupt the respective supply links8and10, respectively, and in this way to separate the voltage-carrying functional elements of the control unit1and of an actuator2connected to the control unit1from the power supply. Since the reed switch6triggers a discharge of the link capacitor13, sufficient time remains for discharging due to the spatial arrangement of the reed switch6with respect to the magnet7until the mounting element22described below can be removed. In general, an order of the actuation on removal of the magnet7can thus be defined by the spatial arrangement of reed switches6,18,26. Thus, especially sensitive operating areas can easily be switched off first and less sensitive operating areas thereafter.

It should be pointed out here that in the exemplary embodiment shown in the figures, the generator34which is connected to the supply link10via the supply terminal17can also be decoupled from the control unit1with the aid of the reed switch18.

In another exemplary embodiment of the invention, a further one or several reed switches can also be provided which are allocated exclusively to the generator34and/or a supply link of the generator34and with a removal of one or the permanent magnet7provide for an interruption of the supply link(s) to the generator34.

FIG. 4also shows that the permanent magnet7is a part of a latching and/or mounting device19for mounting at least one housing part20at the housing3. The permanent magnet7is arranged in a housing lid21of the housing3in its position of usage.

The permanent magnet7is positioned in a mounting element22which, in the present case, is designed as screw23. By this mounting element22, the housing part20, that is to say the housing lid21in the present case, is attached to the other housing part, namely a basic body24of the housing3.

In this arrangement, the permanent magnet7is arranged in a blind hole25provided in the screw23and can there be bonded or crimped with the screw23, for example, in order to prevent the permanent magnet7from falling out of the blind hole25.

So that the two reed switches6and18are not shielded from the magnetic field of the permanent magnet7, the housing3and the mounting element22accommodating the permanent magnet7consist of a magnetically non-conductive material.

According to the exemplary embodiment of the control unit1, shown inFIG. 3, the former has two series-connected reed switches6and26. Both reed switches6and26are connected to a relay driver27which effects switching of the relay14in dependence on the switch position of the two reed switches6and26. If one of the two reed switches6and26is open, the relay14is also moved into an open position with the aid of the relay driver27and the supply link8and10, respectively, are interrupted.

In the case of other exemplary embodiments, not shown in the figures, however, it can also be provided that the control unit1has at least two reed switches connected in parallel with one another. Furthermore, it is possible that at the control unit1, a series circuit of reed switches connected in parallel with one another and/or a parallel circuit of series-connected reed switches is exhibited.

The control unit1is configured to detect a switch position of the reed switches6,18and26of the control unit1. Depending on the switch position of the reed switches6,18,26, the control unit1can switch, by a circuit provided on a processor board28, a motor29of the actuator2connected to the control unit1in its position of usage, to be currentless and/or brake it and stop it.

Furthermore, it is possible to discharge the energy store12, designed as link capacitor13, selectively by the circuit present on the processor board28in dependence on the detected switch position of the reed switches6,18,26.

The processor board28and other electronic elements of the control unit1can be supplied with current via the system part30.

In principle, it is conceivable also to switch the system part30to be currentless with the aid of the switch-off device4, preferably with a time delay.

The electric actuator2and the control unit1are arranged in the same housing3. The actuator2is here connected to the activating terminal5of the electronic control unit1.

As already stated before, the motor29of the actuator2can be switched to be currentless by removing the permanent magnet1. This can be achieved, for example, in that the link capacitor13already mentioned before, of the control unit1can be discharged by removing the permanent magnet7.

Following the motor29, a power transmission32and a power take-off33are provided, for example.

It should be pointed out that in a preferred exemplary embodiment of the electric actuator2, at least one removable permanent magnet7and a reed switch allocated to it, of the switch-off device4are provided at each maintenance opening of the housing3of the actuator2in order to ensure that in the case of an opening of the maintenance openings, the functional elements of the control unit1or of the actuator2, respectively, are switched to be currentless.

The permanent magnet7shown inFIG. 4is designed as rod magnet, the north pole of which is identified by the letter N and the south pole of which is identified by the letter S.

The electronic control unit1and the electric actuator2, respectively, have the switch-off device4which comprises at least one reed switch6,18,26and at least one permanent magnet arranged outside the housing3and removable from the housing3. If the permanent magnet7is removed from its position of usage at the housing3, for example in order to perform maintenance of the electronic control unit1or of the actuator2, respectively, the at least one reed switch6,18,26is opened, as a result of which the supply link8,10between the activating terminal5and the supply terminals9,11,17of the control unit are interrupted in order to switch voltage-carrying functional elements of the control unit1and/or of the electric actuator2to be currentless and thus to effectively prevent an unwanted spark discharge.