JP5285930B2 - Method and apparatus for thermal overload protection of automotive drive trains - Google Patents

Description

  The present invention relates to a device and a method for thermal overload protection of a drive system of a motor vehicle regulating device with electronic pinch protection.

  Adjustment systems driven electrically by automobiles, particularly window opening / closing devices, seat adjusters, door driving devices or slide opening / closing roofs, are usually electronically controlled or adjusted motors and adjustments driven by these motors. In addition to the mechanism, it has electronic pinch protection. With this protection mechanism, a pinching accident is monitored, and in some cases, the drive system is deactivated or reversely driven. This means that the current direction of rotation of the drive unit or the motor is reversed and the sandwiched object is released.

  Such a drive system can further be provided with overload protection, which in particular protects the motor of the drive system, usually configured as a DC motor, from thermal overload. Such thermal overload protection can be achieved in various ways, e.g. by evaluation of the sensor signal of the temperature detector, or by providing a thermistor, e.g. PTC or NTC resistor, in the drive system controller, Despite being able to be implemented by enveloping it in the output coupling of the current source, such measures are usually problematic because of the location of the components to be protected in the drive train and the cost reasons. do not become.

  Nevertheless, in order to achieve a suitable overload protection of the drive train or the component to be protected, in particular the motor, protection is provided for a reliable and reproducible indication of the load state of the component or motor. It is known from EP 0559762 B1 that the current temperature of a component to be calculated is calculated using an algorithm taking into account the component features, in particular thermal resistance, thermal conductivity and thermal volume. .

  Such intelligent software thermal protection utilizes a microcontroller or microprocessor, which uses an algorithm to protect components or motors from overheating. At the same time, the pinch protection has the ability to perform its function at least in the early stage of overheating, and as a result, at least the reverse drive of the drive system is ensured in a pinch accident.

  It is an object of the present invention to propose a device and method for thermal overload protection of a drive train as described at the outset, even when the existing thermal overload protection fails suddenly. In particular, it is intended to reliably prevent the occurrence of fire or smoke in the electric motor.

  With regard to the device, this problem is solved according to the invention by the features of claim 1. Advantageous forms and modifications are the subject of the dependent claims which cite claim 1.

  The above-mentioned problem with respect to the method is solved according to the invention by the features of claim 6. A development suitable for the purpose is the subject of the dependent claims which cite claim 6.

  In this regard, the present invention determines the operating temperature by calculation and, in addition to thermal overload protection, which controls the current system while avoiding simultaneous deactivation of protection by pinching the drive system when an overload occurs, A protection mechanism is provided, which in effect prevents the drive system from fully operating only when the above-described protection system, hereinafter also referred to as software thermal protection, fails completely.

  In this case, in the event that thermal overload protection including pinch protection fails, the motor may emit smoke or fire hazards, depending on the fuse normally present in the current path normally associated with the vehicle. Start with the consideration that you cannot stop. The reason for this is that a motor that is overloaded before producing smoke does not produce a sufficiently high load or motor current to reach the current limit required to trip the corresponding fuse.

  Software thermal protection is therefore a priority, so that this protection always has the highest priority, while another protection system, on the one hand, completely fails the previously mentioned protection system and on the other hand the drive train. It is only activated when the condition that the current operating temperature of the motor or component reaches or exceeds a certain temperature limit is met. This temperature limit value is placed above the temperature limit value for which the protection of the protection system described above, ie its tripping action, is defined.

  Software thermal protection, i.e. thermal overload protection operating on the basis of a corresponding algorithm for determining the load status and operating temperature of the component to be monitored or protected, is at this temperature at about 140 ° C. When the limit value is reached, the energy supply to the motor is activated as long as it is cut off technically. At that time, the pinch protection is not deactivated. When the operating temperature of the motor or component or drive system exceeds this temperature limit by a specific temperature value, the second system for thermal overload protection is activated. The preferred temperature at which this second system for thermal overload protection is activated is a value of about 190 ° C. In this case, the temperature value is basically adjusted on the one hand to ensure that the generation of smoke due to overloading of the motor is prevented and on the other hand not to cause unwanted false tripping.

  Advantageously, a thermal safety element is provided as a second overload protection, which ensures the energy supply to the drive train or motor or component when this second temperature threshold is reached. Cut off. The purpose of this block is to be irreversible. However, reversible shut-off is also suitable, which can be realized for example by a thermistor or bimetal.

  An advantageous variant of the thermal safety element is a narrowed section that takes effect in the manner of a thermal predetermined break in the current conductor or conductor path portion. The thermal safety element then acts in the form of an extension wire or a fuse. This variant is particularly suitable as a component constituting the whole of the current carrier, which leads to the commutator brush of the motor as a conductive path connection, in particular in contact with the armature windings of the rotor of the motor. This variant can therefore be advantageously integrated into existing brush holders, which already carry a current carrier in the form of a conductive path between a brush and a controlled power stage or a power part, for example in the form of a relay. It has as an electrical coupling part between.

  The advantages obtained by the present invention are in particular the provision of two different systems that are staged and prioritized with respect to their tripping, while ensuring reliable thermal overload protection of the drive train or motor or component. At the same time reliable pinch protection and on the other hand reliable prevention of fire hazard or smoke generation are achieved. Based on giving higher priority to thermal protection system (software thermal protection) including pinch protection, the second, lower thermal overload protection has higher higher priority. It is guaranteed that the overload protection is only activated when it fails, for example due to a hardware fault.

The device according to the invention and the method according to the invention thus ensure, on the one hand, reliable tamper protection in addition to reliable overload protection at the same time, and on the other hand unwanted smoke in the event of overload protection faults, including overload protection. At least personal protection against the occurrence of social security is ensured. For this reason, driving parameters (n _ist , I _ist , T _A ) that characterize the driving output and load state of the driving system or components are detected to meet the purpose. Based on the detected operating parameters, a temperature representing the current operating temperature of the drive train is determined.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  Parts corresponding to each other are denoted by the same reference numerals in all the drawings.

  FIG. 1 schematically shows an electric motor or DC motor 1, which has a rotor 2 coupled to a worm 4 via a motor shaft 3 for driving a worm gear 5. The worm gear 5 is part of the transmission, which is connected in the force flow of the adjustment system for the adjustment elements of the motor vehicle, in particular the window opening and closing device. Within the pole head 6 of the motor housing or motor 1 there is also a brush holder 9 having a stator 7, a commutator 8 and a commutator brush.

  The voltage supply of the electric motor 1 that takes place via the vehicle battery 10 in a motor vehicle is regulated, ie controlled or regulated, by a power stage 11 and operating electronics 12 in the form of relays or power semiconductor elements. In the operation electronic circuit 12, a computer unit for pinching protection and thermal overload protection is incorporated as, for example, a separate microcontroller.

Thermal overload (hereinafter referred to as software thermal protection) operates according to a specific algorithm, in particular as described in detail in EP 0559762 B1, all related to the contents of this specification To do. This algorithm is based on operating condition parameters, in particular around the load or actual current I _ist detected by the current sensor 13 a, for example the current motor rotational speed n _ist detected by the Hall sensor 13 b, as well as around the motor 1, for example. based on the temperature sensor 13c that he, operation of the motor 1 temperature T _B to first the load state and on the basis of which to calculate the operating temperature T _B. Sensor 13c for detecting the ambient temperature and external temperature T _A is within the motor housing 6 of the motor 1 as time went well in accordance with the installation space available, or are located in the immediate vicinity of at least the motor housing.

If the algorithm or operating the operating temperature T _B of the electronic circuit software Based on determined or calculated motor 1 of 12 exceeds the temperature threshold T ₁ given first advance, the operation electronics output or energy supply That is, a control signal S _OFF is generated for cutting off the actual or motor current I _M guided from the power stage 11 to the commutator 8 via the brush or brush holder 9 and to the winding of the rotor 2 via the commutator 8. To do. In such an overload state, the motor 1 only stops if the operation electronic circuit 12 identifies a pinching accident due to the risk of pinching an object or object in the adjustment system of the drive mechanism driven by the motor 1. Rather, it is at least slightly reversed by its previous reversal of the direction of rotation, so that the object that is possibly pinched is released.

  Thermal overload protection is undertaken by an additional safety element 14 in case the operating electronics 12 or the hardware component responsible for software thermal protection fails. This safety element 14 is connected in a current or output path 15 between the power stage 11 and the commutator brush or brush holder 9.

  The thermal safety element 14 operates in a purposeful manner according to the principle of an extension line or fuse, and is as indicated by the dashed line in the functional module representing the thermal safety element 14.

  The thermal safety element 14 can be formed as a current element to the motor 1 or a spring element associated in the output path. This spring element can then be held between two brazing points on both sides in a current path, for example formed as a conductive path portion, and can be brought into electrical contact therewith. If an overload occurs, i.e. if a correspondingly high current load or motor current flows for a certain period of time, any of the brazing points will melt, so that the spring bias of the safety element 14 causes the contact to occur spontaneously. Will be blocked.

For example, FIGS. 2 and 3 show a biased spring element 141 whose spring ends 141a, 141b are mechanically held and electrically connected using braze contacts in the form of corresponding braze pads 16a and 16b in the current path 15. In contact. If the operating temperature T _B of the motor 1 exceeds a second temperature threshold T ₂ at the first higher value than the temperature limit value T _1, or (wax pad 16a in this case) of the brazing pad melts. As a result, the spring element 141 on the basis of the spring bias will contract in the direction of the arrow, thus the current path 15 is interrupted to a further current supply of the load to the motor current I _M in this location.

In the embodiment according to FIGS. 4 and 5, the thermal safety element is formed as a leaf spring or a flexible spring 142. Again, the spring element 142 that is mechanically held by the braze pads 16a, 16b on both sides and that is in electrical contact with the current path 15 reaches or exceeds the _second temperature limit value T ₂ , corresponding to the motor 1. Following the heat generation, any of the brazing pads 16 (in this case, the brazing pad 16b) melts to cut off the current supply in the current path 15.

In the embodiment according to FIGS. 5 and 6, the current path 15 itself is formed by a predetermined breakage point 143 formed by narrowing the cross section, and this breakage point becomes the thermal safety element 14. Following heat generation of the corresponding motor 1 of reached or exceeded the operating temperature T _B is here led to only as caused thermally predetermined breaking point 143 to form a safety element 14, so that the current I _M and hence Energy supply to the electric motor 1 is irreversibly interrupted.

The first temperature limit value T ₁ for software thermal protection is specified, for example, at about 140 ° C., whereas the second temperature limit value T _{2 at which} additional, but subordinate thermal overload protection is activated. For example, the value is about 190 ° C. In this case, the temperature difference ΔT ₁₂ between the first temperature limit value T ₁ and the second temperature limit value T ₂ ensures the pinching protection, so that the upper reversible software thermal protection is thermal safety. It is defined to always be prioritized over the underlying overload protection provided by element 14. Therefore, the added lower thermal overload protection in the form of a safety element 14 may cause a fire hazard in the motor 1 when the upper thermal overload protection fails, especially due to software errors or hardware faults. Or the generation of smoke is reliably avoided. As a result, appropriate interpersonal protection is guaranteed here as well.

  FIG. 8 shows an advantageous embodiment, in which a safety element 14 as shown in FIGS. 2 to 7, in particular FIGS. 6 and 7, is incorporated in the brush holder 9 of the motor 1. . It will be appreciated that the safety element 14 is housed in the conductive path portion 17 of the current path 15 leading to the commutator brush in the brush holder 9 in the form of a predetermined break point or in the functional manner of an extension wire or fuse. .

1 is a schematic diagram of functional elements of an electric motor for an electric window opening and closing drive unit in an automobile and an operating device of the electric motor having two-stage thermal overload protection. FIG. It is explanatory drawing of the state by which the thermal safety element formed as a spring element between two brazing locations is not removed. It is explanatory drawing of the state by which the thermal safety element formed as a spring element between two brazing locations was removed. It is explanatory drawing of the state by which the thermal safety element formed as a leaf | plate spring is not removed. It is explanatory drawing of the state by which the thermal safety element formed as a leaf | plate spring was pulled out. It is explanatory drawing of the state by which the safety element formed as a thermal type predetermined fracture location is not removed. It is explanatory drawing of the state by which the safety element formed as a thermal type predetermined fracture location was pulled off. FIG. 8 is an illustration of the safety element according to FIGS. 6 and 7 as an overall component of the brush holder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 2 Rotor 3 Motor shaft 4 Worm 5 Worm gear 6 Motor housing / pole head 7 Stator 8 Commutator 9 Brush holder 10 Battery 11 Power stage 12 Operation electronic circuit 13a Current sensor 13b Hall sensor 13c Temperature sensor 14 Safety element 15 Current path 16 Brazing pad 17 Conductive path portion 141 Spring element 142 Plate / flexure spring 143 Predetermined breaking point
I _ist Actual / Load current n _ist Motor rotation speed
I _M Load / Motor current
T _A Ambient / External temperature
T _B Operating temperature
T ₁ First temperature limit value
T _2nd temperature limit value

Claims (6)

A device for thermal overload protection of a drive system of an adjusting device having an electronic pinch protection and an electric motor (1),
A computer unit (12) and a thermal safety element (14);
The computer unit (12) uses an algorithm that takes into account the operating parameters (I _ist , T _A ) that are conditioned on the operation of the electric motor (1), and operates the driving system or components of the driving system. to confirm the temperature (T _B), the operating temperature (T _B) is, reaches the first temperature limit value set with a highest priority for thermal overload protection of the driving system (T ₁₎ When this is done , the operation of the electric motor is stopped, the energy supply to the drive system is continued without being cut off, and the electronic pinch protection is provided to remain in an active state,
In the thermal safety element (14), the operating temperature (T _B ) is a temperature limit value higher than the first temperature limit value (T ₁ ), and the drive system (1) or a component thereof When the second temperature limit value (T ₂ ), which is a temperature limit value set as a temperature at which it is assumed that a fire hazard or smoke begins to occur, is cut off, the energy supply to the drive system is cut off A thermal overload protection device for a drive system, which is provided as described above. Even when the calculation unit (12) has reached the _first temperature limit value (T ₁ ), when the occurrence of a pinching accident is detected, the calculation unit (12) releases the pinched object. The apparatus of claim 1, wherein the apparatus is provided to operate the drive train. The thermal safety element (14) is incorporated in a current carrier (15, 16) that conducts a load current (I _M ) of the electric motor (1), the current carrier (15, 16) being a conductive path. 3. A device according to claim 1 or 2, characterized in that it is provided as a coupling and communicates with the commutator brush (9) of the electric motor (1). In a method for thermal overload protection of a drive system of a regulating device comprising an electric motor (1),
During operation of the drive system, pinching of the object is monitored, and when pinching accident occurrence is detected, electronic pinching protection that stops or reversely drives the electric motor (1) is activated,
The operating temperature (T _B ) of the drive system or its components is determined,
Wherein the determined operating temperature (T _B) is compared with the first temperature limit value set with a highest priority for thermal overload protection of the driving system (T _1), the temperature limit value ( upon reaching the T _1), the conjunction allowed to stop the operation of the electric motor, the energy supply is allowed to remain jamming protection of the electronic so as to continue without interrupting the active state to the drive system,
The operating temperature (T _B ) is a temperature limit value that exceeds the first temperature limit value (T ₁ ) by a predetermined temperature value (ΔT ₁₂ ), and the drive system (1) or components thereof The thermal safety element (14) is tripped when the _second temperature limit value (T ₂ ) is reached, which is the temperature limit value set as the temperature at which a fire hazard or smoke is expected to start. A method for protecting a drive system from thermal overload, wherein the supply of energy to the drive system is cut off. At least one of the current load current (I _ist , T _B ), the rotational speed (n _ist ) of the electric motor (1), and the ambient temperature (T _A ) of the drive system in the drive system is The method according to claim 4, characterized in that it is detected as an operating parameter for determining the operating temperature (T _B ). The operating temperature (I _ist , T _A ) is calculated based on a model that maps the load or load dependent thermal characteristics of the drive train or its components and / or by using an algorithm. 6. The method according to claim 4 or 5, wherein:

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