DE102014215916A1 - Sensor device for an electric motor and electric motor with the sensor device - Google Patents

Abstract

Electric motors can generate high temperatures during operation due to waste heat. A local increase in temperature occurs especially in the region of the stator, in particular in the deflection regions of the stator windings - also called winding head - on. It is an object of the present invention to provide a sensor device for an electric motor and an electric motor with the sensor device, which is characterized by a particularly safe operating behavior or distinguished. For this purpose, a sensor device 14 for determining the temperature of a stator 5 of an electric motor 1, with a sensor housing 17, with a sensor 18 for detecting the temperature, wherein the sensor 18 is disposed in the sensor housing 17, wherein the sensor housing 17 has a bottom portion 19 with a bottom 23 for bearing on the stator 5 in a detection direction 16 and a base portion 20 for fixing the sensor device 14, wherein the sensor 18 detects the temperature across the bottom 23, proposed, wherein the bottom portion 19 relative to the base portion 20 in the detection direction 16 is arranged movable and wherein the sensor device 14 is designed for use in a receiving opening 15 of a flange 4 of the electric motor 1.

Description

The invention relates to a sensor device for determining the temperature of a stator of an electric motor, comprising a sensor housing, with a sensor for detecting the temperature, wherein the sensor is arranged in the sensor housing, wherein the sensor housing has a bottom portion with a bottom for resting on the stator in a Detection direction and a base portion for mounting the sensor device, wherein the sensor detects the temperature across the ground and wherein the bottom portion is arranged relative to the base portion in the detection direction movable. Furthermore, the invention relates to an electric motor, in particular for driving a vehicle with the sensor device.

Electric motors can generate high temperatures during operation due to waste heat. A local increase in temperature occurs especially in the region of the stator, in particular in the deflection regions of the stator windings - also called winding head - on. In unfavorable cases, it can lead to overheating and damage to the electric motor. Against this background, it is common to integrate a temperature sensor into the electric motor to monitor the temperature.

The publication DE 101 30 982 A1 discloses a temperature sensor for a stator winding of electric motors, wherein a sensor is received in a shrink tube and wherein this assembly is at least partially installed in the stator.

The publication EP 1 278 291 A2 , which forms the closest prior art, discloses a temperature sensor which is integrated in an electric motor and has a displaceable sensor section for abutment with a stator of the electric motor.

It is an object of the present invention to provide a sensor device for an electric motor and an electric motor with the sensor device, which are characterized by a particularly good operating characteristics or distinguished.

This object is achieved by a sensor device having the features of claim 1 and by an electric motor having the features of claim 10. Preferred or advantageous embodiments of the invention will become apparent from the dependent claims, the following description and the accompanying drawings.

In the context of the invention, a sensor device for determining the temperature of a stator of an electric motor is proposed. In principle, the electric motor may be an arbitrary electric motor, in particular a stationary electric motor, for example in a work machine. However, the electric motor is particularly preferably designed for integration in a vehicle. In particular, the electric motor is used to generate a drive torque for this vehicle.

The sensor device comprises a sensor housing and a sensor, wherein the sensor - optionally with connection cables - is arranged in the sensor housing. The sensor particularly preferably comprises a temperature resistance, in particular a thermistor, or an NTC resistor, a PTC element, a Pt100 element, a NiCrNi element, a KTY element or a bimetallic element, etc. The sensor housing is in particular as formed a multi-part sensor housing.

The sensor housing has a bottom portion and a base portion. The base section is designed for fastening the sensor device. In particular, the base portion for mounting the sensor device in or on the electric motor, in particular on a motor housing of the electric motor is formed.

The bottom portion has a bottom, wherein the bottom is disposed at a free end of the sensor device. In operation, the bottom faces the stator. The bottom serves to rest on the stator, in particular for contacting the stator. Particularly preferably, the base contacts the stator winding, in particular the winding head of the stator. To support the floor has a support surface, wherein the support surface is particularly preferably flat or flat. The soil is placed on the stator in a detection direction. In particular, the detection direction is aligned perpendicular to the support surface. Particularly preferably, the floor contacted the stator with the support surface area. Particularly preferably, the support surface extends in a radial plane perpendicular to a main axis of the electric motor and / or parallel to an axial end face of the stator winding of the stator.

The bottom is in a thermally conductive connection with the sensor so that the temperature of the stator can be detected via the sensor.

It is proposed that the bottom portion is movably arranged relative to the base portion in the detection direction. Thus, the bottom portion and the base portion form no rigid assembly, but the bottom portion can be moved in the detection direction such that the bottom towards the stator, in particular to Stator winding, in particular to the winding head, can be tracked.

It is a consideration that electric motors are like all other modules provided with manufacturing tolerances. For the operation of the sensor device, however, it is important that this physical contact with the stator, in particular to the stator winding, in particular to the winding head occupies, since even small layers of air or unnecessary heat-insulating intermediate layers would lead to a falsification of the temperature result. By the mobility of the bottom portion relative to the base portion is achieved that the base portion, for example, can be fixed to a motor housing of the electric motor and the bottom portion can optionally be brought tolerance-compensating to the stator. This tolerance compensating measure ensures that the temperature measurement on the stator and thus on the electric motor is improved. As a result, the electric motor can be brought closer to its power limit during operation, since the determined temperature values have a small error width. As a result of the better temperature control, higher powers and / or a safer operating behavior of the electric motor can thus be achieved. Thus, the performance of the sensor device and thus of the electric motor is improved by the proposed embodiment of the sensor device.

In the context of the invention it is proposed that the sensor device is designed for use in a receiving opening, in particular passage opening of a flange, in particular designed as an end flange or bearing plate of the electric motor. In particular, the sensor device has at least one partial section, which is accessible after installation of the sensor device in the electric motor. This accessible section can be used on the one hand for wiring the sensor device. On the other hand, it is possible that the accessible section forms a mechanical interface for repair and even replacement of the sensor device, in particular parts of the sensor device. Thus, the sensor device is formed maintenance and repair friendly compared to the prior art. The relative mobility ensures that tolerances between the flange and the stator can be bridged or when replacing parts of the sensor device, a correct measuring position can be set again. through the interaction of the better accessibility, the maintenance and repair-appropriate training and / or the reliable operation of the operating characteristics are improved overall.

In a preferred embodiment of the invention, the sensor device has a first spring device for acting on a biasing force on the bottom portion in the detection direction. Thus, the bottom portion is biased elastically in the detection direction by the biasing force, so that it is moved in the direction of the stator due to the biasing force and thereby applies itself to the stator automatically and thus reliable. The first spring means acts between the base portion and the bottom portion. Thus, the first spring means spreads the bottom relative to the anchoring of the base portion, that is, for example, relative to the motor housing of the electric motor. In this embodiment, in addition to the simplified and tolerance-compensating initial assembly still has the advantage that over the life of the electric motor, a physical contact between the bottom and the stator, in particular the stator winding, in particular the winding head, is maintained by the bottom portion is biased. Thus, the safe temperature determination is achieved not only at the beginning of the life of the electric motor, but ensured over the entire life, since the bottom portion is optionally tracked by the first spring means elastic.

It is in principle possible that the sensor is connected to the bottom portion such that it is entrained or entrained by the bottom portion when the bottom portion is displaced by the first spring means in the detection direction. Alternatively or additionally, the sensor device has a second spring device for acting on a second biasing force on the sensor in the detection direction, wherein the second spring device acts between the base portion and the sensor. By the second spring means, the sensor is tracked elastically in the detection direction. Two variants can be distinguished: In the first variant, the sensor device has the first and the second spring device, wherein the first spring device biases the bottom section in the detection direction and the second spring device tracks the sensor in the detection direction. In a second alternative, the sensor device has only the second spring device, wherein the second spring device biases the sensor in the detection direction, wherein the sensor presses against the ground and thereby entrains the bottom portion in the detection direction. In both variants, however, it is ensured that both the physical and therefore heat-conducting contact between the stator and the bottom section as well as the physical and therefore heat-conducting contact between the bottom and the sensor is also permanently ensured.

In a possible development or alternative of the invention, the sensor device has a third spring device for acting on a biasing force on the bottom portion, in particular on the ground, wherein the third spring means between the sensor and the bottom portion acts and is designed as a heat-conducting connection. The third spring device is thus realized so that it is arranged spreadingly between the bottom and the sensor and at the same time is designed as a heat-conducting connection. Particularly preferably, the third spring device is formed variable in length. For example, the third spring device may be formed as a metal spring, in particular as a spiral compression spring made of metal, wherein the spring action is ensured by the compression spring and the heat-conductive connection by the design of metal and the physical and thus heat-conducting contact between the metal spring and the ground on the one hand and the metal spring and the sensor on the other hand. The third spring device can be implemented in combination with the first spring device or even alone without the first and the second spring device.

In a preferred structural embodiment of the invention, the base portion has a socket portion portion and a plug portion portion, which are preferably detachably connected to each other and / or connected. The bushing portion is fixed in or to the electric motor or integrated and / or attached thereto. The base section, in particular the bushing section section and the plug section section, if appropriate, is in each case preferably designed as a plastic part, in particular as a plastic injection-molded part. The plug part section, however, can be dismantled and thus represents a freely accessible portion of the sensor device.

The bushing part section preferably has a first receiving space for receiving the bottom section and a second receiving space for receiving the plug part section. The receiving spaces are each preferably designed so that they only partially or partially accommodate the bottom portion or the plug portion section.

In a preferred constructional development of the invention, an intermediate wall with a passage opening for the sensor is arranged between the first receiving space and the second receiving space. The first spring device is preferably formed as an elastic annular body or as a compression spring device, which is supported on the bottom portion and on the intermediate wall. An annular body of a temperature-stable elastomer material as a further alternative ensures in the component in addition to the tolerance compensation and the pressing force in the detection direction and the sealing of the sensor interior.

In a preferred embodiment of the invention, the bottom portion is formed as a Tasthülsenabschnitt, wherein the Tasthülsenabschnitt is slidably mounted in the detection direction relative to the base portion. In particular, the bottom portion, specifically formed as the key sleeve portion, and the base portion are formed telescopically. It is preferred that the bottom portion are arranged in the base portion, in particular in the first receiving space. Between the bottom portion and the base portion, a, in particular circumferential, sealing means may be formed, which prevents substances from the electric motor, in particular oil from the current operation or casting compound during initial assembly, can penetrate into the first receiving space.

In the embodiment as Tasthülsenabschnitt it is preferred that the Tasthülsenabschnitt includes the bottom and a sleeve. It is preferable that the heat resistance, for example expressed in W / K, of the bottom is made smaller than the heat resistance of the sleeve. Thus, the temperature in the interior of the Tasthülsenabschnitts is dominated by the outside temperature in the region of the bottom, in particular by the temperature of the stator, the stator winding or the winding head, whereas the temperature adjacent to the sleeve has a much smaller influence on the internal temperature of the Tasthülsenabschnitts. It is a further consideration of the invention that a high accuracy of the measurement of the temperature of the stator winding or the winding head for an effective control of the electric motor is advantageous. The continuation acts on the physical measurement of the temperature and improves it by the fact that the sensor device, in particular the Tasthülsenabschnitt is structurally designed so that the temperature applied to the sensor temperature is determined by the temperature of the stator winding, by disturbing temperature influences through the sleeve can be reduced and also a rapid temperature transition from the stator winding to the sensor is achieved by the ground adjacent, in particular physically contacting, is arranged to the stator winding. Particularly preferably, the bottom and the sleeve are made of different materials, in particular of different material composites. Thus, in particular, it may be provided that the floor is designed to be multi-layered. Values of less than 0.5 W / mK, in particular less than 0.2 W / mK, are preferred values for thermal conductivity of the sleeves accepted. The wall thickness of the sleeve is preferably more than 0.5 millimeters, in particular more than 1 millimeter. In one possible structural embodiment, the sleeve has a free inner diameter of 3 millimeters and an outer diameter of 5 millimeters. By contrast, a value greater than 1 W / mK, preferably greater than 5 W / mK, is preferably assumed for the thermal conductivity of the soil. In a preferred embodiment of the invention, the thickness of the bottom is less than 0.8 millimeters, preferably less than 0.5 millimeters and in particular less than 0.2 millimeters executed. In these or other exemplary constellations, the thermal resistance of the sleeve is preferably at least five times as large, preferably at least ten times greater than the thermal resistance of the bottom.

In a preferred embodiment of the invention, the bottom has an insulating layer for electrical insulation, wherein the insulating layer adjacent, preferably immediately adjacent to the stator winding is arranged, in particular in physical contact with the stator winding. It can be provided that voltages greater than 300 volts are applied to the stator winding, whereas it is preferred that the voltages are less than 1000 volts. These voltages make an electrical insulation between the sensor and the stator winding necessary, this electrical insulation being realized by the insulating layer.

In a preferred structural embodiment of the invention, the insulating layer is elastic. In particular, the insulating layer is elastically deformable. In a preferred embodiment, the electrical insulation layer is formed as a plastic matrix with ceramic bodies as a filler. Particularly preferably, the plastic matrix is formed by a silicone.

Alternatively or additionally, the insulating layer is formed as a silicone film with embedded ceramic bodies, in particular as a so-called Sil pad, which are sufficiently known from the power electronics. It is a film material which has silicone as a plastic matrix, are embedded in the ceramic body for insulation, such as AIN, BrN or AlxOy.

Such a film on the one hand has the advantage that a high electrical insulation effect is given and on the other hand the advantage that it is elastically deformable, so that it can be molded to the surface of the stator winding. In particular, the surface of the stator winding is elastically pressed into the insulating layer. In this case, the insulating layer yields by at least 0.05 millimeters, preferably by at least 0.1 millimeters. Fiberglass particles can also be used as filler. In a further development, it is particularly preferred that the insulating layer is formed as an adhesive film, which can be glued to the sleeve in a simple manner during assembly in order to simplify the assembly.

An advantageous embodiment provides that the sleeve fixes a preferably completely circumferential edge portion of the bottom of the stator winding and / or pushes. The assembly of the sensor device or the sensor envelope is thereby considerably simplified. Particularly preferably, the bottom, in particular the insulating layer, adhered to a free end of the sleeve so that a pre-assembly is formed. Subsequently, this subassembly is pressed with the ground on the sensor winding. Characterized in that the sleeve fixes the edge portion of the bottom, and the surface portion of the bottom, which is arranged congruently with an opening of the sleeve, clamped onto the stator winding and thereby pressed. Thus, a very good heat coupling between the bottom and stator winding is achieved with simple installation.

In a possible development of the invention, the bottom has a metallic supporting body, wherein the metallic supporting body is insulated from the stator winding by the insulating layer. It can be provided on the one hand, that the support body is embedded in the insulation layer on both sides. However, it is preferred that the bottom has a layer sequence, wherein first the insulation layer and subsequently the support body is arranged as a further layer. The support body has, for example, a plate section which is aligned parallel to the insulation layer. By the support body can be achieved that also the surface portion of the insulating layer, which is congruent with the opening of the sleeve, can be better pressed onto the stator winding. For example, it is also possible that the support body has fixing means, such as fixing arms, which can be supported on the sleeve in order to improve the contact pressure on the stator winding.

In a preferred embodiment of the invention, the sensor device has a heat-conducting device, wherein the sensor is thermally conductively connected to the bottom via the heat-conducting device. For the implementation of the heat conduction device, various alternatives can be selected:
In the simplest embodiment, the floor consists exclusively of the insulating layer. Since this is preferably elastic, the sensor can be pressed into the insulating layer, so that it forms the heat-conducting device.

In an alternative embodiment of the invention, the heat conducting device may be formed as a thermally conductive, shapeless mass, in particular as a thermal paste in particular with electrically conductive fillers of metals or graphite, which is introduced into the sensor enclosure and on the one hand the ground, in particular the insulating layer, and others contacted the sensor. In particular, the sensor may be embedded in the heat conducting device. Such a shapeless heat conducting device can also be applied to the support body.

In a further alternative of the invention, the heat conducting device is designed as a mechanical, in particular as a metallic heat conducting device. For example, the heat conducting device is designed as the third spring device, which is supported on the ground on the one hand and on the sensor on the other so that on the one hand the bottom is pressed against the stator winding and on the other the heat conducting device is pressed against the sensor in order to achieve optimal heat transfer to reach.

In a preferred embodiment of the invention, the sensor has at its free end a glass bead in which a temperature element of the sensor is integrated or embedded. With this glass bead, the sensor is pressed into the insulating layer, embedded in the heat conducting device or pressed onto the heat conducting device.

The material of the sleeve is preferably made of a plastic, in particular a high-temperature resistant plastic, in particular without fillers, such as PA66, PPS, PEEK and can be produced, for example by extruding cost endlessly as a hollow cylindrical tube and cut to length as needed.

Preferably, it is provided that the first spring device acts on the sleeve and presses the bottom over the sleeve to the stator winding, in particular to the winding head.

Another object of the invention relates to an electric motor with the sensor device having the features of claim 10. The electric motor comprises a motor housing, which forms an outer housing of the electric motor. In particular, the motor housing has mechanical interfaces for coupling to a surrounding construction, in particular to the vehicle. In the motor housing, the stator is arranged. Particularly preferably, the electric motor is designed as an internal rotor, wherein the stator surrounds a rotor of the electric motor coaxially and concentrically. The stator and / or the rotor define with the motor axis a main axis of the electric motor. The stator has the stator winding, in particular in the form of several wound coils, which extends, for example, along the main axis of the electric motor and has coil ends or winding heads at the free ends. These areas of the stator winding, which are hereinafter referred to uniformly as winding head or winding heads, form turning points in the stator winding, wherein lines which initially run in an axial direction with respect to the main axis along the stator are diverted in the opposite direction. Furthermore, the stator preferably has a laminated core, which is particularly preferably designed as a plurality of laminations. The parting planes of the lamination plates are perpendicular to the longitudinal extent of the main axis and / or the motor axis. The stator winding is particularly preferably received in a bobbin, which forms an electrical insulation between the stator winding and the laminated core. Furthermore, the bobbin forms a winding aid in the winding of the stator winding. The winding heads are in an annular arrangement coaxial with the main axis or to the motor axis at each end of the stator and are preferably separated by the bobbin on an axial end face of the laminated core of the stator. The sensor device is at least partially disposed within the motor housing, in particular close to the stator. In particular, the sensor device measures the temperature of the stator winding or the temperature in the region of the stator winding. Particularly preferably, the sensor device is in contact with the ground on the stator winding, in particular on the winding head.

In a preferred application of the invention, an inner space between the motor housing and the stator winding is filled with a potting compound, wherein it is particularly preferred that the potting compound is formed as a heat-conducting potting compound. For example, a filler is arranged or embedded in the potting compound, which supports the heat transfer. The basic idea of such a potting compound is that the temperature occurring at the stator winding can be transferred from the stator winding to the motor housing in a particularly simple manner.

The motor housing may comprise a pot housing, wherein the pot housing is arranged coaxially to the main axis. Preferably, the pot housing is integrally formed. Alternatively, the pot housing is formed as an assembly with a preferably hollow cylindrical cooling jacket and a mounted on the cooling jacket in a radial plane extending to the main axis flange. The interior is also located in an edge area between the cooling jacket and the flange. The potting compound is achieved that the Potting compound rests gap-free both on the stator winding and on the flange and / or the cooling jacket and / or the motor housing.

In principle, it would be possible to provide a placeholder for the sensor device in the casting process and to assemble this subsequently. However, it is particularly preferred that the sensor housing is embedded in the potting compound. In particular, the sensor housing is first mounted and subsequently filled the potting compound. This approach has the advantage that the sensor housing is fixed by the potting compound, in particular is secured materially. In addition, a receiving opening in the motor housing, in particular in the pot housing, in particular in the flange, can optionally be additionally sealed by the potting compound with the sensor housing when filling the potting compound.

Due to the fact that the sensor device in a preferred embodiment has the plug part section which is designed to be detachable or retrofittable, the socket section with the bottom section may initially be inserted and cast with the first spring device during assembly. In a subsequent step, the actual sensor with the plug section can be used later or replaced if necessary. This results in particularly valuable advantages when the bushing portion is attached to the bottom portion already in the production cohesively in the motor housing by the potting compound in terms of mountability and / or ease of repair of the sensor device.

A possible further object of the invention relates to a vehicle with the electric motor, wherein the electric motor for generating the driving torque for the vehicle is realized.

Further features, advantages and effects of the invention will become apparent from the following description of a preferred embodiment of the invention and the accompanying figures. Showing:

1 a schematic longitudinal section through a portion of an electric motor as an embodiment of the invention;

2 in the same sectional view an enlarged view of the sensor device in the electric motor of the 1 ;

3 the sensor device in the 2 in a separate state;

4a , b, c an illustration for mounting the sensor device in a schematic longitudinal sectional view;

5 a schematic illustration for the preparation and construction of the metal spring element in the sensor device;

6 in the same representation as the 5 an alternative embodiment of the metal spring element in the 5 ,

The 1 shows a section of a longitudinal sectional view of an electric motor 1 as an embodiment of the invention. The electric motor 1 serves to generate a drive torque for a vehicle, in particular for a passenger car. The electric motor 1 has a motor housing 2 on, of which only a partial section is shown in the longitudinal sectional view. The illustrated portion is formed as a pot housing and includes a cooling jacket 3 , which assumes a straight hollow cylindrical shape, and a flange 4 , which at one end of the cooling jacket 3 arranged and connected in one piece with this. The flange 4 forms in particular a bearing plate of the electric motor 1 , The cooling jacket 3 may be provided in some embodiments with cooling channels for water cooling, so that the flange 4 over the cooling jacket 3 is cooled. cooling jacket 3 and flange 4 may alternatively be bolted together, for example

In the motor housing 2 is a stator 5 arranged, which forms in its entirety a straight hollow cylinder. In the stator 5 , in particular within the hollow cylinder, a rotor is arranged, which in the 1 but not shown in the drawing. The stator 5 , the rotor not shown or the motor housing 2 define a major axis H, which is the motor axis and / or the axis of rotation of the stator 5 equivalent.

The stator 5 has a laminated core 6 on, which is composed of a plurality of laminations, wherein the laminations are in the surface extension rectified to radial planes to the main axis H. In the 1 is on an axial end face of the laminated core 6 a bobbin 7 arranged in the schematized shown windings of a stator winding 8th are arranged. In the axial end region of the stator 5 becomes the stator winding 8th also as a winding head 9 designated. The windings of the stator winding 8th extend in the laminated core along the main axis H and are in the region of the winding head 9 deflected in the direction so that they run back and forth in the tangential direction to the main axis H. The bobbin 7 is made of plastic, for example, and has the task of the stator winding 8th . in particular the winding head 9 , from the laminated core 6 electrically isolate and the second to form a winding aid and receiving the windings. The bobbin 7 has an opening in the axial direction receiving space 10 which is formed in its entirety as an annulus and in which the winding head 9 is arranged.

In an interior 11 of the motor housing 2 , which extends in the axial extension between the flange 4 and the axial end face of the laminated core 6 and in the radial direction between the cooling jacket 3 and a cylinder jacket boundary 12 extends, is a potting compound 13 brought in. The potting compound 13 is gap-free and contacting the cooling jacket 3 , on the flange 4 as well as on the stator winding 8th and thus at the winding head 9 at. In the potting compound 13 thermally conductive particles are introduced, so that they are used as a heat-conductive potting compound 13 is trained. The task of the potting compound 13 is it, heat from the stator winding 8th , in particular of the winding head 9 , to the metallic flange 4 or to the cooling jacket 3 to guide and thereby the winding head 9 to cool. In the production of the electric motor 1 first becomes the stator 5 in the cup-shaped housing consisting of cooling jacket 3 and flange 4 mounted and subsequently the potting compound 13 introduced so that the stator 5 is already in its final position and subsequently poured or cast.

During operation of the electric motor 1 Waste heat is generated, the waste heat in particular in the winding head 9 arises. To measure the temperature at the winding head 9 includes the electric motor 1 a sensor device 14 , The sensor device 14 is in a receiving opening 15 which may be formed as a bore, for example, in the flange 4 arranged and / or passes through this. The sensor device 14 is with a detection direction 16 aligned parallel to the main axis H. With a free end of the sensor device 14 contacts the sensor device 14 the stator winding 8th , in particular the winding head 9 , in the detection direction 16 ,

In the 2 is the sensor device 14 shown enlarged in the same longitudinal section. The sensor device 14 has a sensor housing 17 on, in which a sensor 18 is arranged. The sensor housing 17 can be in a base section 20 and in a floor section 19 be divided. The base section 20 splits up into a plug section 21 and in a jack section 22 , The plug section 21 and the female part section 22 are each formed as plastic components, in particular injection molded plastic components. As can be seen in particular from the 3 which gives the sensor device 14 in the same representation, but partially dismantled shows are the plug section 21 and the female part section 22 formed detachable and / or connectable to each other.

The base section 20 is partially in the flange 4 inserted and with this example cohesively on the potting compound 13 connected. This is how the base section points 20 , in particular the bushing section 22 , a plug-in area that over the receiving opening 15 to the interior 11 projects as well as a bearing area on the flange 4 or as in the 1 shown in a receiving recess of the flange 4 lies.

The bottom section 19 is at the free end of the base section 20 , in particular of the female part section 22 in the base section 20 , in particular in the bushing section 22 , in the detection direction 16 slidably received, so that an axial length of the sensor device 14 in the detection direction 16 by moving the bottom section 19 relative to the base section 20 and thus to the flange 4 or to the motor housing 2 is possible. The bottom section 19 has a floor 23 on, which has an end-side termination of the bottom section 19 forms and which in a radial plane to the main axis H and / or in a plane perpendicular to the detection direction 16 lies. The floor 23 is with its outer surface or contact surface directly contacting on the stator winding 8th , in particular on the winding head 9 placed. This is the bottom 23 ideal or at least best possible with the stator winding 8th or the winding head 9 thermally coupled. Furthermore, the bottom section 19 a sleeve 26 which are in the detection direction 16 extends and ends through the floor 23 is completed.

The sensor 18 has a sensor element 24 on, wherein the sensor element 24 for example, is designed as an NTC element. The sensor element 24 is in a glass bead 28 arranged. However, it may also be unprotected or with a different sheathing. The sensor 18 includes a sensor cable 29 for signal transmission, which one or more wires 30 having, which with an insulating jacket 31 surrounded and electrically isolated. At a free end of the sensor cable 29 is the vein 30 stripped and runs freely to the sensor element 24 in the glass bead 28 , For mechanical stabilization is located between the free end of the insulating jacket 31 and the glass bead 28 a shrink tube 32 who made the glass bead 28 stops and opposite the insulating jacket 31 mechanically supported.

The sensor element 24 is in the bottom section 19 arranged and eg in a heat conducting device 25 embedded. The heat conducting device 25 , which, for example, as a thermally conductive mass or paste can be formed, lies with one side directly contacting the ground 23 on, with the other side envelops the heat conduction device 25 the sensor element 24 , so that a very good heat transfer between the stator winding 8th , in particular the winding head 9 and the sensor element 24 is formed.

The sleeve 26 is formed as a tubular portion and is made for example of a plastic material as continuous material. The floor 23 and the sleeve 26 are made of different materials or composite materials. It is envisaged that a thermal resistance of the soil 23 to the sensor element 24 significantly smaller than the thermal resistance through the sleeve 26 is. This will be for the floor 23 a material or composite material chosen which has a greater thermal conductivity than the material or the material composite of the sleeve 26 , The coupling with regard to the thermal conductivity between soil 23 and sensor element 24 is through the heat conducting device 25 optimized.

Background of this embodiment is that for control and control processes of the electric motor 1 the current temperature at the stator winding 8th , in particular at the winding head 9 is relevant. The potting compound 13 or a cooling oil in the interior 11 On the other hand, the measurement of this temperature may be adversely affected because of the heat-conducting properties of the potting compound 13 or the cooling oil, the temperature with increasing distance to the stator winding 8th or to the winding head 9 falls sharply. The same applies to the flange 4 , which is made of metal and the cooling jacket 3 can be cooled very well. By choosing the floor 23 with a very low thermal resistance and the sleeve 26 With a significantly higher thermal resistance is achieved by the sensor element 24 significantly the temperature of the stator winding 8th , in particular of the winding head 9 is measured and interference due to the potting compound 13 and / or the flange 4 be suppressed. Thus, the temperature measurement is faster and more accurate than in other embodiments of the sensor device 14 ,

However, it should be noted that about the stator winding 8th Voltages between 350 and 450 volts are conducted. Thus, the sensor must 18 , in particular the sensor element 24 , electrically isolated from the stator winding 8th or the winding head 9 become. The floor 23 has at least one insulation layer 27 on. In the in the 2 the embodiment shown forms the insulating layer 27 the outermost layer of the soil 23 , The insulation layer 27 is formed in this embodiment as a foil material which consists of a silicone material and are embedded in the ceramic body or particles. Such substance networks are known under the name Sil-pad and are used in the line electronics, on the one hand to achieve a thermal connection and on the other hand electrical insulation.

The insulation layer 27 is elastic, so that they are at a pressing of the bottom section 20 on the stator winding 8th or on the winding head 9 elastically deformed, as schematized in the sequence in the 4a , b, c is shown. In these figures, the bottom section 19 with the sleeve 26 and the floor 23 formed as the insulation layer 27 shown.

In the 4a is the bottom section 19 spaced from the stator winding 8th or the winding head 9 , In the 4b is the bottom section 19 on the stator winding 8th , in particular on the winding head 9 pressed. It can be seen that the ground 23 or the insulation layer 27 deformed, in particular elastically deformed. This results in a particularly good thermal coupling of the soil 23 or the insulation layer 27 to the stator winding 8th or the winding head 9 ,

During manufacture or during assembly of the electric motor 1 will be at least the base section 20 , in particular the bushing section 22 , with the bottom section 19 mounted before the potting compound 13 is filled. Thus, in a first step, the base section 20 in the receiving opening 15 introduced and arranged so that the ground 23 on the stator winding 8th , in particular the winding head 9 is applied and elastically deformed, as in the 4b is shown. In a subsequent process step, the potting compound 13 filled. Through the potting compound 13 becomes the base section 20 , in particular the bushing section 22 firmly bonded. Furthermore, through the bushing section 22 when filling the potting compound 13 the receiving opening 15 be sealed. Alternatively, the base section 20 , in particular the bushing section 22 , in the receiving opening 15 be glued and thus sealed on the one hand and prefixed to the other.

The 4c shows the sensor 18 in an enlargement, wherein it can be seen that the sensor element 24 in an envelope, especially in the glass bead 28 , is arranged, wherein the sensor 18 such under bias in the bottom section 19 is mounted that the glass bead 28 in the ground 23 is pressed. Due to the elastic deformation of the soil 23 becomes the contact surface between the ground 23 and the glass bead 28 enlarged, so that the thermal connection is improved. This embodiment is used in particular when the ground 23 only through the insulation layer 27 is formed.

To a pressing of the soil 23 on the stator winding 8th and in particular to the winding head 9 to improve, pushes the sleeve 26 on a border area of the soil 23 , This will be the floor 23 in the edge region directly through the sleeve 26 pressed. The middle part of the soil 23 becomes indirectly through the sleeve 26 pressed. Optionally complementary may be in the ground 23 a reinforcement, in particular a support body (in the 4a , b, c not shown), such as a metal disc, be incorporated to the pressing on the stator winding 8th , in particular on the winding head 9 to improve. Furthermore, the contact pressure of the central region of the soil 23 through the sensor 18 implemented or at least supported, the sensor 18 is mounted with bias in the axial direction and presses the middle area immediately.

Structurally, the bushing section has 22 a first and a second recording room 33 . 34 on which of each other by an intermediate wall 35 are separated. In the first recording room 33 is the bottom section 19 in the detection direction 16 slidably arranged. The seal of the first recording room 33 and optionally in addition the guidance of the bottom section 19 can have a sealing device 36 take place, which at an exit of the first receiving space 33 in the socket section 22 is used. For example, the first recording room 33 in cross-section perpendicular to the detection direction 16 circular shaped, wherein the bottom portion 19 coaxial and concentric in the first receiving space 33 is arranged. Through the sleeve 26 and the sealing device 36 becomes a temperature decoupling between the bushing section 22 and the bottom section 19 implemented.

In the first recording room 33 is a first spring device 37 arranged, wherein the first spring means 37 is designed functionally, the bottom section 19 in the detection direction 16 to load with a biasing force, so that the ground 23 with the biasing force on the stator winding 8th or on the winding head 9 is pressed. Structurally considered is the first spring device 37 formed as a coil spring in the embodiment of a compression spring. The coil spring is coaxial with the sensor 18 arranged so that it extends through the free middle part of the coil spring. With a free end, the spring device is supported 37 at the partition 35 and thus over the bushing section 22 on the motor housing 2 from. At the other end, the first spring device is supported 37 at the free end of the sleeve 26 off so that the preload force on the sleeve 26 in the ground 23 flows and this on the stator winding 8th or the winding head 9 imprints.

The second recording room 34 forms a receptacle for the plug section 21 , which provides a cover for the bushing section 22 forms. The sensor 18 proceeds from the first recording room 33 through an opening in the partition 35 through the second recording room 34 , is deflected at right angles and ends in a contact socket 38 , An end portion of the sensor 18 rests in the region of the right angle bend on the plug part section 21 at a support area 41 From or is even connected to this example cohesively or positively. In a common through the bushing section 22 and the plug section 21 formed socket 39 can be a sensor plug 40 be introduced, the sensor 18 signal technically and / or electrically contacted.

In a state where the male part section 21 and the female part section 22 are connected as intended, is the length of the sensor 18 between the support area 41 and the floor 23 such that at least or exactly a bulge 42 the sensor yields, with the bulge 42 in a direction perpendicular to the detection direction 16 is shaped. To support the bulge 42 has the bushing section 22 a bulge area 43 on top of the rough shape of the bulge 42 when closing plug section 21 and female section 22 pretends. The length of the sensor 18 and the bulge area 43 are coordinated so that between the bulge area 43 and the bulge 42 of the sensor 18 a free area 44 arises.

The sensor device 14 has a second spring device 45 which is formed as a spring plate and which is arranged so that it the bulge 42 of the sensor 18 in the direction of the bulge area 43 pushes back. Due to the fact that the sensor is oversized, this spring load is converted into a preload force, which is the free end of the sensor 18 , in particular the sensor element 24 against the ground 23 pushes and thus a secure heat-conducting connection between the sensor element 24 and the floor 23 reached. The second spring device 45 For example, may have a spring plate section, which in opposite directions to the bulge 42 is curved. As can be seen by comparing the 2 and 3 shows, the second spring device is supported 45 at the plug portion 21 and off when closing plug section 21 and female section 22 by the drag on the ground 23 biased to the sensor. Alternatively, spring devices can be used by the moving together of the plug section 21 and the book section 22 be stretched and deformed so that the bulge area 43 flattened of the sensor and so the sensor is extended until he hits the ground 19 suppressed. In this case, the outdoor area 44 only with relaxed spring device larger and is when inserting the plug section 21 reduced.

Between the ground 23 , which in this embodiment as the insulating layer 27 is formed, and the glass bead 28 or the sensor element 24 is a metal spring element 46 arranged, which serves as a heat conducting device 25 acts and at the same time a mechanical support of the soil 23 forms. The exact structure of the metal spring element 46 is in the 6 shown. In the 5 is initially an alternative embodiment of the metal spring element 46 shown.

The 5 shows in three lines a schematic illustration for producing an alternative of the metal spring element 46 for the sensor device 14 in the previous figures. In the top line is a side view, in the middle line a top view and in the bottom line instructions for manufacturing technology given. The further description relates essentially to the middle row. Starting from a metal strip 47 are cut out in a first step recesses, the separation process is implemented for example via laser beam cutting. Here are two or four wings 48 cut out, with the wings 48 are distributed uniformly or in the direction of rotation. In the bottom line cutting gaps and holes are indicated, the middle row shows the recesses in the metal strip 47 , in the uppermost row is initially in the lateral view, only the metal strip 47 to recognize.

In a step II the wings become 48 in a direction out of the plane of the metal strip 47 bent out, so that in its entirety a shell for surface recording of the glass bead 28 form. In a next step III, the metal spring element 46 then cut free and in this way from the sheet metal strip 47 separated. Next to the wings 48 has the cut metal spring element 46 a circumferential base plate 49 on, which is still in the plane of the tin strip 47 is arranged. The base plate 49 is between the sleeve 26 and the floor 23 arranged so that the metal spring element 46 is defined in the situation. The metal spring element 46 is designed in particular as a stamped or bent part. By the metal spring element 46 becomes a good thermal connection of the sensor element 24 to the ground 23 and thus to the stator winding 8th or the winding head 9 reached.

In the 6 is another embodiment of a metal spring element 46 shown which in the sensor device 14 in the 1 to 3 is used and manufactured in a similar manner as the previous embodiment, so that the description of the 5 is referenced. In contrast to the embodiment in the 5 is the metal spring element 46 according to the 6 completely within the tube opening of the sleeve 26 arranged.

LIST OF REFERENCE NUMBERS

1

 electric motor

2

 motor housing

3

 cooling jacket

4

 flange

5

 stator

6

 laminated core

7

 bobbins

8th

 stator

9

 winding head

10

 accommodation space

11

 inner space

12

 Cylinder mantle boundary

13

 potting compound

14

 sensor device

15

 receiving opening

16

 detection direction

17

 sensor housing

18

 sensor

19

 bottom section

20

 base section

21

 Plug Part

22

 Hub portion

23

 ground

24

 sensor element

25

heat conducting

26

 shell

27

 insulation layer

28

 glass bead

29

 sensor cable

30

 veins

31

 insulating

32

 shrinkable tubing

33

 first recording room

34

 second recording room

35

 partition

36

 seal means

37

 first spring device

38

 Contact socket

39

 Rifle

40

 sensor connector

41

 support area

42

 bulge

43

 Auswölbungsbereich

44

 outdoor Space

45

 second spring device

46

 Metal spring element

47

 metal strip

48

 wing

49

 baseplate

H

 main axis

U

 Surroundings

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10130982 A1 [0003]
• EP 1278291 A2 [0004]

Claims (10)

Sensor device ( 14 ) for determining the temperature of a stator ( 5 ) of an electric motor ( 1 ), with a sensor housing ( 17 ), with a sensor ( 18 ) for detecting the temperature, wherein the sensor ( 18 ) in the sensor housing ( 17 ), wherein the sensor housing ( 18 ) a bottom section ( 19 ) with a floor ( 23 ) for resting on the stator ( 5 ) in a detection direction ( 16 ) and a base section ( 20 ) for mounting the sensor device ( 14 ), wherein the sensor ( 18 ) the temperature above the ground ( 23 ), wherein the bottom section ( 19 ) relative to the base portion ( 20 ) in the detection direction ( 16 ) is movably arranged and the sensor device ( 14 ) for use in a receiving opening ( 15 ) of a flange ( 4 ) of the electric motor ( 1 ) is trained. Sensor device ( 14 ) according to claim 1, characterized by a first spring device ( 37 ) for applying a biasing force to the bottom section ( 19 ) in the detection direction ( 16 ), wherein the first spring device ( 37 ) between the base section ( 20 ) and the bottom section ( 19 ) acts. Sensor device ( 14 ) according to one of the preceding claims 1 or 2, characterized by a second spring device ( 45 ) for applying a biasing force to the sensor ( 18 ) in the detection direction ( 16 ), wherein the second spring device ( 45 ) between the base section ( 20 ) and the sensor ( 18 ) acts. Sensor device ( 14 ) according to any one of the preceding claims, characterized by a third spring means for applying a biasing force to the bottom portion ( 19 ), wherein the third spring means between the sensor ( 18 ) and the bottom section ( 19 ) acts and is designed as a heat-conducting connection. Sensor device ( 14 ) according to one of the preceding claims, characterized in that the base section ( 20 ) a female part section ( 22 ) and a plug section ( 21 ), wherein the bushing section ( 22 ) a first recording room ( 33 ) for receiving the bottom section ( 19 ) and a second reception room for ( 34 ) Receiving the plug section ( 21 ) having. Sensor device ( 14 ) according to one of the preceding claims, characterized in that between the first receiving space ( 33 ) and the second recording room ( 34 ) an intermediate wall ( 35 ) with a passage opening for the sensor ( 18 ), wherein the first spring device ( 37 ) is formed as a compression spring device, which at the bottom portion ( 19 ) and at the partition ( 35 ) is supported. Sensor device ( 14 ) according to one of the preceding claims, characterized in that the bottom section ( 19 ) is formed as a key sleeve portion, wherein the key sleeve portion in the detection direction ( 16 ) relative to the base portion ( 20 ) is slidably mounted. (Sealing means) Sensor device ( 14 ) according to claim 7, characterized in that the Tasthülsenabschnitt a sleeve ( 26 ) and the ground ( 23 ), wherein the thermal resistance of the sleeve ( 26 ) greater than the thermal resistance of the soil ( 23 ) is trained. Sensor device ( 14 ) according to one of the preceding claims, characterized in that the bottom ( 23 ) is electrically insulating and at the same time elastic. Electric motor ( 1 ) in particular for a vehicle, characterized by a sensor device ( 14 ) according to any one of the preceding claims. wherein the sensor device ( 14 ) in the receiving opening ( 15 ) of the flange ( 4 ) of the electric motor ( 1 ) is used.

Images