geared motor

Abstract

Geared motor comprising a gearbox driven by an electric motor, wherein a lubricant sensor for detecting lubricant is provided at the lowest point of the interior of the electric motor, characterized in that the interiors of the electric motor and the gearbox are sealed against each other in a lubricant-tight manner, the sensor is arranged in and screwed into a drain plug, wherein the sensor comprises a connector part at its end projecting outwards from the motor housing, wherein the sensor itself is provided with an external thread on its housing and is screwed into a threaded bore of the drain plug with this external thread, wherein the sensor has a plug connection for connecting the signal lines at its end projecting outwards from the housing of the motor.

Description

The invention relates to a geared motor. It is known that gearboxes are at least partially filled with a lubricant, such as oil. In geared motors, an electric motor is arranged on the input side of the gearbox. From EP 1 562 031 A2, a sensor for detecting a leak in a machine is known as the closest prior art. From DE 23 43 752 A1 a drive motor for mining machines used in underground mining is known. The invention is based on the objective of improving environmental protection, particularly in the operation of systems that include drives. According to the invention, the problem is solved in the geared motor according to the features specified in claim 1. Key features of the invention for the geared motor are that it comprises a gearbox driven by an electric motor, and a lubricant sensor for detecting lubricant is provided at the lowest point of the electric motor's interior. An advantage of this is that even small amounts of lubricant can be detected, thus enabling early warnings or corrective actions. In an advantageous embodiment, the sensor comprises a capacitor arrangement connected to a DC and / or AC voltage source. A key advantage is that a simple capacitive sensor can be used. Such sensors are particularly effective at distinguishing and detecting various media, such as water or oil. In a preferred embodiment, the lubricant is an oil, in particular a synthetic or organic oil. The advantage here is that any oil that penetrates the system quickly flows to the lowest point, thus enabling a rapid triggering of an action or warning. In an advantageous embodiment, the sensor determines the capacitance of a capacitor arrangement, particularly at a DC voltage and / or at one or more frequencies of the AC voltage applied to the arrangement. In particular, the sensor determines the dielectric constant of the medium surrounding its capacitor arrangement, particularly at a DC voltage and / or at one or more frequencies of the AC voltage applied to the arrangement. It is advantageous that precise measurements are possible, especially the determination of the mass or mass fractions and type of the media surrounding the sensor's capacitor arrangement. Preferably, the sensor is also designed to detect water, particularly condensation. According to the invention, the sensor is arranged in a drain plug, in particular screwed into it. An advantage is that an existing threaded bore for a drain plug can be used by means of the modification according to the invention. Therefore, the sensor housing can be relieved of stress and only needs to be tightly connected to the drain plug. This plug can be screwed onto the housing of the electric motor with high torque. According to the invention, the sensor includes a connector at its end projecting outwards from the motor housing. An advantage of this is that cables containing the signal lines can be quickly and easily connected electrically to the sensor. In an advantageous embodiment, the sensor housing includes a first electronic circuit suitable for converting the sensor signals into data that can be transmitted on a bus system according to the relevant bus protocol. The advantage here is that the sensor, comprising this first electronic circuit, can be used as a bus participant. In a preferred design, the sensor data can be transmitted via a bus system to another electronic circuit. An advantage here is that the additional circuit can be set up as a central computing unit, which can then trigger appropriate actions. Further advantages arise from the sub-claims. The invention will now be explained in more detail with reference to illustrations: Fig. 1 shows a geared motor according to the invention, which comprises a gearbox 1 partially or completely filled with lubricant, the driving shaft of which is the rotor shaft 4 of an electric motor 2 driving the gearbox or is at least connected to it. The rotor shaft 4 is supported in the housing of the electric motor by at least one bearing. The interiors of the electric motor 2 and the gearbox 1 are sealed against each other to prevent the presence of lubricant. For this purpose, at least one shaft seal is provided, the sealing lips of which interact with a surface on the rotor shaft that has been machined to serve as a running surface. A shaft seal seat is provided in the gearbox housing for the shaft seal, in which the seal is positioned. If the shaft seal fails, lubricant can penetrate into the interior of the engine. According to the invention, a lubricant sensor, for example an oil sensor, is arranged inside the electric motor, which makes the presence of lubricant, such as oil, detectable. In a first embodiment according to the invention, the measuring principle of the oil sensor is based on a determination of the temperature when a direct and / or alternating voltage is applied to two capacitor plates pointing into the interior of the electric motor. In other embodiments of the invention, different measuring principles are used. Advantageously, the sensor is positioned at the lowest point inside the electric motor. This allows even the smallest amounts of lubricant to be detected, as even the smallest amounts accumulate at this point and can then be detected there. The sensor's signal lines are connected to an electronic circuit, preferably via a bus line, so that upon detection of lubricant, an immediate warning message and / or shutdown of the electric motor and / or other measures, such as activating an additional seal between the gearbox and motor, can be triggered. Preferably, the sensor is arranged and integrated in a drain plug designed for draining condensate from the electric motor. This allows the lowest point of the electric motor's interior to be used for collecting both condensate and lubricant. In further development, the sensor is designed in such a way that it detects the accumulated amount of condensation and / or lubricant, or at least emits a warning signal from a certain critical amount of condensation and / or lubricant. In particular, the sensor is able to detect small amounts of lubricant penetrating condensation and thus determine the presence of lubricant even when condensation is present. The described actions are then carried out accordingly. The drain plug can be tightly connected to the engine housing. In further embodiments according to the invention, the sensor itself is provided with an external thread on its housing and is screwed into a threaded bore of the drain screw. A plug connection for connecting the signal lines is provided at its end protruding from the motor housing. The sensor signals are preferably transmitted via Ethernet or a fieldbus protocol, such as ASI, CAN, Interbus or Profibus. Reference symbol list 1 Gearbox 2 Motor 3 Oil sensor 4 Rotor shaft

Claims

Geared motor comprising a gearbox driven by an electric motor, wherein a lubricant sensor for detecting lubricant is provided at the lowest point of the interior of the electric motor, characterized in that the interiors of the electric motor and the gearbox are sealed against each other in a lubricant-tight manner, the sensor is arranged in and screwed into a drain plug, wherein the sensor comprises a connector part at its end projecting outwards from the motor housing, wherein the sensor itself is provided with an external thread on its housing and is screwed into a threaded bore of the drain plug with this external thread, wherein the sensor has a plug connection for connecting the signal lines at its end projecting outwards from the housing of the motor. Geared motor according to claim 1, characterized in that the sensor comprises a capacitor arrangement which is connected to a DC and / or AC voltage source. Geared motor according to at least one of the preceding claims, characterized in that the lubricant is an oil, in particular a synthetic or organic oil. Geared motor according to at least one of the preceding claims, characterized in that the sensor determines the capacitance of a capacitor arrangement, in particular at a DC voltage and / or at one or more frequencies of the AC voltage applied to the arrangement. Geared motor according to at least one of the preceding claims, characterized in that the sensor determines the dielectric constant of the medium surrounding its capacitor arrangement, in particular at a DC voltage and / or one or more frequencies of the AC voltage applied to the arrangement. Geared motor according to at least one of the preceding claims, characterized in that the sensor is also designed to detect water, in particular condensation. Geared motor according to at least one of the preceding claims, characterized in that the sensor in its housing comprises a first electronic circuit which is suitable for converting the sensor signals into data that can be transmitted on a bus system according to the associated bus protocol. Geared motor according to at least one of the preceding claims, characterized in that the sensor data can be transmitted to a further electronic circuit via a bus system.

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