Method for producing component for electric machine and corresponding device for producing component

Abstract

The invention relates to a method for producing a component (2) for an electric machine, the component (2) having a magnetic core (4) which has at least one recess (7) which receives at least one wire winding (8), runs parallel to a longitudinal central axis of the component (2) and completely penetrates the magnetic core (4), and wherein during the introduction of an impregnating agent into the at least one recess (7), the impregnating agent is introduced into the at least one recess (7). The component (2) is oriented in such a way that the impregnating agent enters the at least one recess (7) in the direction of the longitudinal central axis under the influence of gravity. According to the invention, the temperature of the at least one wire winding (8) is first adjusted to a lower first temperature selected to reduce the viscosity of the impregnating agent and then to a higher second temperature selected to increase the viscosity of the impregnating agent by applying an electric current during the introduction of the impregnating agent into the at least one recess (7). The invention also relates to a device (1) for producing a component (2) for an electric machine.

Description

Technical Field

[0001] The present invention relates to a method for producing a component for an electric machine, wherein the component comprises a magnetic core having at least one groove which accommodates at least one wire winding, extends parallel to the longitudinal center axis of the component, and completely penetrates the magnetic core, wherein during the introduction of an impregnating agent into the at least one groove, the component is oriented such that the impregnating agent enters / is forced into the at least one groove in the direction of the longitudinal center axis due to the influence of gravity. The present invention also relates to a device for producing a component for an electric machine. Background Art

[0002] The prior art discloses, for example, document DE 1 538 918 A. This document describes a method for impregnating motor windings, wherein the windings are heated, and then an impregnating agent capable of polymerization or polyaddition reaction, optionally together with additives to influence the material properties, is introduced into the windings, which is then gelled and finally hardened. Here, a funnel for introducing the impregnating agent into the windings is placed on an upright motor part carrying the windings, and the entire required amount of impregnating agent is poured into the funnel. The gelling time is set so that gelling begins as soon as the windings are completely impregnated.

[0003] In addition, document US2022 / 0094248 A1 discloses a method for manufacturing a stator of a rotating electric machine, wherein the stator has a coil and a stator core, a groove for accommodating the coil is formed in the stator core, and wherein a filling material having a low viscosity at a first temperature and a high viscosity at a second temperature higher than the first temperature is filled into the groove from a feeding side, wherein the manufacturing method includes: a first step, i.e., generating a temperature difference in the stator core so that the injection side presents a first temperature and the opposite side of the injection side presents a second temperature; a second step, i.e., injecting the filling material from the injection side while maintaining the temperature difference.

[0004] Furthermore, document WO 2022 / 128632 A1 discloses a method for impregnating rotor coils with an impregnant, wherein the rotor includes a rotor shaft, a rotor core mounted on the rotor shaft, and a coil arranged in a channel in the rotor core, wherein the rotor core has a first end and a second end opposite the first end, and the channel extends along the rotor core from the first end to the second end, wherein the method includes: positioning the rotor in a vertical position so that the first end is above the second end; applying the impregnant to the coil from the first end when the rotor is in the vertical position so that the impregnant flows along the coil through the channel from the first end to the second end due to gravity; and when applying the impregnant to the coil, curing the impregnant only at the second end so as to close the second end with the cured impregnant while allowing the channel to be filled with the impregnant. Summary of the Invention

[0005] The object of the present invention is to provide a method for producing a component for an electric machine, which method has advantages over known methods and in particular enables rapid and reliable filling of recesses with an impregnating agent.

[0006] According to the invention, this object is achieved by a method for producing a component for an electric machine having the features according to claim 1. Provision is made here for the temperature of at least one wire winding to be adjusted first to a lower first temperature selected to reduce the viscosity of the impregnating agent and then to a higher second temperature selected to increase the viscosity of the impregnating agent by applying an electric current during the introduction of the impregnating agent into the at least one groove.

[0007] Advantageous embodiments and suitable improvements of the invention are given in the dependent claims. It should be noted that the embodiments described in the description are not restrictive; on the contrary, any changes to the features disclosed in the description, claims and drawings can be implemented.

[0008] The method is used to produce a component for an electric motor. The component is preferably a component of the electric motor, but can obviously also exist separately from the electric motor, in particular until the component is mounted on or in the electric motor. The electric motor preferably has a stator and a rotor, wherein the rotor is mounted rotatably relative to the stator about a rotor axis of rotation. The electric motor can be of any design, for example, an asynchronous motor, a permanently excited synchronous motor, or a separately excited synchronous motor. Preferably, the stator or rotor of the electric motor forms the component, so that the component is designed as a stator or rotor of the electric motor and is produced according to the described method. Of course, it can also be provided that both the stator and the rotor of the electric motor are present as such components, i.e., both are produced according to the described method.

[0009] In any case, the component comprises a magnetic core, in which at least one groove, but preferably a plurality of grooves, is formed. The magnetic core is preferably made of a soft magnetic material, in particular electrical steel sheets or the like. Whenever a description refers to at least one groove or the groove, the discussion is always equivalent. Therefore, explanations relating to at least one groove also apply to the groove, and vice versa. Furthermore, if applicable, the discussion can also be transferred to each of the plurality of grooves. The groove extends parallel to the longitudinal center axis of the component, which in the case of a stator and a rotor preferably coincides with, i.e. corresponds to, the rotor axis of rotation. The plurality of grooves are arranged spaced apart from one another in the circumferential direction, in particular evenly distributed in the circumferential direction. Particularly preferably, the grooves are each at the same distance from the longitudinal center axis.

[0010] The groove completely penetrates the core in the axial direction with respect to the longitudinal center axis, so that the groove passes through the opposite end sides of the core in the axial direction while forming an opening. The groove defines the opposite sides of the magnetic poles of the core when viewed in the circumferential direction. The groove is delimited inwardly in the radial direction by the groove bottom, which is also formed by the core. Preferably, the groove is open outward in the radial direction, in particular over its entire extension in the axial direction. The radially built-in area of ​​the core from which the magnetic poles originate can also be referred to as the base of the core. The magnetic poles can be designed with pole shoes on their side away from the base, so that the magnetic poles are also widened in the circumferential direction on their outer sides in the radial direction. The pole shoes are preferably arranged spaced apart from each other in the circumferential direction, preferably continuously in the axial direction.

[0011] At least one wire winding is arranged in the groove. The wire winding surrounds, for example, one of the magnetic poles, in particular each of the magnetic poles is respectively surrounded by such a wire winding. At least one wire winding, i.e., the exactly one wire winding or these multiple wire windings preferably have multiple turns, which respectively surround the corresponding magnetic poles. As long as the description refers to a wire winding or at least one wire winding, these discussions are always equivalent. In this regard, the explanations about at least one wire winding can be transferred to the wire winding, and the embodiments about the wire winding can be transferred to at least one wire winding. If there are multiple wire windings, the explanations about the wire winding or at least one wire winding can preferably be transferred to each wire winding in the multiple wire windings.

[0012] During component production, an impregnating agent is introduced into the grooves in order to impregnate the wire windings located there. This serves, on the one hand, to mechanically secure the wire windings, but also has other effects, such as increasing the electrical insulation capacity of the wire windings, improving heat dissipation from the wire windings, and improving protection against environmental influences, such as humidity, lubricants, etc. These additional aspects are particularly important when the electric machine is used as a traction motor for a motor vehicle.

[0013] In principle, there are several possible methods for introducing the impregnating agent into the grooves, in particular the dripping method, hot dipping method, and roller dipping method. Other methods include, for example, the vacuum method (VI-dipping), the vacuum pressure method (VPI-dipping), and the atmospheric pressure impregnation method (dip & bake-dipping). However, the disadvantage of these methods is that the impregnating agent is not only introduced into the grooves but also reaches the outside of the component. This requires laborious cleaning of the component after impregnation. On the other hand, the impregnating agent can enter coolant channels formed in the magnetic core in addition to the grooves, such as coolant channels parallel to the grooves. Accordingly, the impregnating agent can close or block the coolant channels, making cleaning of the coolant channels very laborious. In some cases, cleaning is even impossible.

[0014] For this reason, it is provided that the impregnating agent is introduced in such a way that it reaches, for the most part, or even only, the wire windings and / or the grooves, but does not reach the outside of the component. Therefore, the impregnating agent is introduced into the grooves in such a way that, under the influence of gravity, it enters the grooves in the direction of the longitudinal center axis. To this end, the component is accordingly arranged so that its longitudinal center axis is oriented parallel to, or initially substantially parallel to, the gravity vector. In this regard, the influence of gravity on the impregnating agent should act only, or at least almost exclusively, in the axial direction relative to the longitudinal center axis.

[0015] The impregnating agent is preferably applied via at least one nozzle, which is arranged above the component, in particular above the groove or one of the grooves, or above a winding head formed by the wire winding, with reference to the gravity vector. Preferably, the nozzle is arranged above the winding head, from which the wire winding extends into the adjacent groove, so that the impregnating agent flows through the winding head into both grooves. For example, the impregnating agent can be applied using multiple nozzles, in which case each of the nozzles is arranged above one of the grooves or above multiple winding heads, so that the impregnating agent discharged from the respective nozzle is influenced by the force of gravity acting on the impregnating agent into the groove below the nozzle, for example, past the region of the winding head or wire winding arranged outside the groove.

[0016] In this case, it can be provided that the impregnating agent first encounters the winding head formed by the wire winding, which is formed outside the groove of the wire winding. The impregnating agent enters the winding head, in particular between the turns of the wire winding forming the winding head, and is influenced by gravity in the direction of the groove and ultimately into the groove. For example, the component may have such winding heads on opposite sides in the axial direction. Accordingly, after it is discharged from the nozzle, the impregnating agent first enters the upper winding head of the winding head, then flows through the groove and from the groove into the lower winding head of the winding head. The impregnating agent can then be drained from the component through the lower winding head. This process reliably avoids laborious cleaning of the component, because the impregnating agent mainly enters the groove and does not reach the outside of the component or enter the coolant channels.

[0017] The impregnating agent is a material having different viscosities at different temperatures. In particular, the impregnating agent has a first, lower viscosity in a first temperature range and a second, higher viscosity in a second temperature range. The impregnating agent is, in particular, an impregnating resin, such as an epoxy resin, in particular a 1K epoxy resin or a 2K epoxy resin, or a polyester resin, in particular a 1K polyester resin or a 2K polyester resin, such as a polyesterimide resin. The first temperature range is typically above ambient temperature, so that, in order to introduce the impregnating agent into the groove, it is usually necessary to first adjust the temperature of the impregnating agent, i.e., for example, to a temperature below the first temperature or below the first temperature range.

[0018] Before the impregnating agent is introduced, the component is preheated, in particular to a temperature of at least 100°C. The tempered impregnating agent is then introduced into the recess of the preheated component. However, the impregnating agent is typically at a lower temperature than the component, so that heat is transferred from the component to the impregnating agent introduced into the recess. Because this procedure does not introduce heat into the component during the introduction of the impregnating agent, but rather the component cools over time due to heat transfer to the impregnating agent and / or heat loss to the surrounding environment, the viscosity of the impregnating agent increases due to the increased temperature, and the flowability of the impregnating agent gradually deteriorates.

[0019] If impregnating agent is present in the grooves, the component is heat-treated, i.e., the temperature is increased, specifically to a temperature within the second temperature range, so that the viscosity increases, in particular until the impregnating agent completely solidifies, for example, by gelling. During this heat treatment, the impregnating agent is typically not introduced further, i.e., the introduction is interrupted before the heat treatment. It can happen that the grooves are not completely filled with impregnating agent due to the increase in viscosity of the impregnating agent caused by the temperature increase during its introduction into the grooves. Consequently, cavities are formed that are free of impregnating agent and remain permanently in the component after the impregnating agent solidifies. This can lead to poor retention of the wire winding, poor heat dissipation, and / or imbalance of the component.

[0020] To this end, it is now provided that the wire winding is brought to a specific temperature during the introduction of the impregnating agent into the groove, specifically, first to a first temperature and then to a second temperature. This means that the second temperature is not brought to the wire winding only after the impregnating agent has been introduced or after the introduction has been completed or interrupted. Rather, the introduction is preferably carried out continuously during the temperature adjustment, in particular while the temperature is adjusted from the first temperature to the second temperature or until the second temperature is reached. The first temperature is preferably within the first temperature range already mentioned, and the second temperature is within the second temperature range also already mentioned. The first temperature of the wire winding is therefore selected such that the impregnating agent has a low viscosity, resulting in good flowability. For example, the first temperature of the wire winding corresponds to the first temperature of the impregnating agent, at which the impregnating agent has its lower viscosity, while the second temperature of the wire winding corresponds to the second temperature of the impregnating agent, at which the impregnating agent has its higher viscosity.

[0021] The temperature of the wire winding is regulated by applying an electric current to the wire winding, so that a current with a specific voltage and a specific amperage flows through the wire winding. This approach has the advantage that the wire winding (between the turns of which the impregnant is to be introduced) is not only heated indirectly by other elements, such as the magnetic core, but also directly regulated to the specific temperature. Thus, using Joule's law, or more precisely, the thermal effect of the current, the temperature of the wire winding can be regulated very specifically, first, so that the impregnant reliably enters the grooves and between the turns of the wire winding. Subsequently, the temperature is regulated, also using the thermal effect of the current, to increase the viscosity of the impregnant, in particular irreversibly.

[0022] The first temperature is particularly preferably selected so that the viscosity of the impregnating agent is as low as possible. For this purpose, the first temperature is selected depending on the impregnating agent used. The second temperature is preferably selected so that the impregnating agent solidifies within a specific time period, so that at the end of this time period, the impregnating agent has a substantially higher viscosity. The described method allows for particularly effective and efficient introduction of the impregnating agent into the grooves and, in this case, also between the turns of the wire winding.

[0023] A refinement of the present invention provides for the use of a magnetic core in which at least one coolant channel penetrates an end face of the magnetic core and / or extends parallel to at least one groove. The coolant channel serves to guide the coolant during operation of the electric machine. Preferably, the coolant channel is continuously closed along its entire extent. Preferably, the coolant channel penetrates an end face of the magnetic core, in particular, the coolant channel penetrates an opposite end face of the magnetic core. The opening formed by the coolant channel penetrating the end face of the magnetic core is preferably in the same plane as the opening formed by the groove penetrating the same end face.

[0024] Preferably, the coolant channel completely and continuously penetrates the magnetic core in an axial direction based on the longitudinal center axis. The coolant channel is particularly arranged parallel to the groove. For example, viewed in the radial direction, the coolant channel is located further inward than the groove, so that the distance between the coolant channel and the longitudinal center axis is less than the distance between the groove and the longitudinal center axis. It can be provided that only a single coolant channel is designed in the magnetic core. However, preferably, there are multiple coolant channels. The description of the coolant channel in this specification can be applied accordingly to at least one coolant channel, and vice versa. In addition, this embodiment can preferably be applied to each coolant channel of the multiple coolant channels, if any. The coolant channel enables particularly reliable cooling of the components during operation of the motor.

[0025] A refinement of the invention provides that the temperature of at least one wire winding is regulated by regulating the voltage and / or the current intensity of the current flowing through the at least one wire winding, in particular by closed-loop regulation. The electrical resistance of the wire winding varies with its temperature, so that the resistance is temperature-dependent. At the same time, the resistance depends on the voltage and the current intensity, the current intensity being in particular a function of the voltage and the resistance, and / or the voltage being a function of the current intensity and the resistance. For example, the voltage and the current intensity are regulated in such a way that the temperature and therefore the resistance remain constant, so that the electrical power supplied to the wire winding and the resulting heat are regulated overall by regulating the current intensity. It can be provided that the voltage is regulated to a target voltage and / or the current intensity is regulated to a target current intensity, in particular to a first target voltage and / or a first target current intensity selected to achieve a first temperature, and then to a second target voltage and / or a second target current intensity selected to achieve a second temperature.

[0026] For example, the voltage and / or current intensity is regulated in a closed-loop manner, preferably within the scope of temperature regulation. For this purpose, it is provided, for example, that the temperature of at least one wire winding is measured with a sensor, or that the temperature of the wire winding is calculated based on the voltage and current intensity or based on the resistance of at least one wire winding. The current temperature of the wire winding, which can also be called the actual temperature, is thus either measured or calculated, the latter using the voltage and current intensity. The voltage and / or the current intensity of the current flowing through the wire winding is adjusted in such a way, in particular in a closed-loop manner, that the actual temperature changes towards a target temperature, in particular until it reaches this target temperature. In other words, the actual temperature of the wire winding is adjusted to a target temperature by regulating the voltage and / or current intensity, wherein the target temperature temporarily corresponds to the first temperature and temporarily corresponds to the second temperature. The described method enables the temperature of the wire winding to be regulated quickly and effectively.

[0027] A further development of the invention provides that the impregnating agent is introduced into the at least one groove at an impregnating agent flow rate that is selected as a function of the temperature of the at least one wire winding, wherein, in particular, a greater impregnating agent flow rate is selected when the temperature of the at least one wire winding is within a specific temperature range than when the temperature is outside this temperature range. As already explained, the viscosity of the impregnating agent depends on its temperature and, therefore, indirectly, also on the temperature of the wire winding.

[0028] The impregnating agent is introduced into the groove with an impregnating agent flow rate (i.e., the amount of impregnating agent per unit time). The impregnating agent flow rate is, for example, a mass flow rate or a volume flow rate. Since the viscosity of the impregnating agent depends on the temperature, it is useful to select the impregnating agent flow rate as a function of the temperature of the wire winding. Provision can be made for the impregnating agent flow rate to be determined during the introduction of the impregnating agent into the groove as a function of the current actual temperature of the wire winding, which actual temperature is, for example, measured or calculated. However, provision can also be made for the impregnating agent flow rate to be determined before the impregnating agent is introduced into the groove, i.e., by using a temperature profile that the temperature of the wire winding follows during the introduction of the impregnating agent into the groove.

[0029] It is particularly preferred to provide that, when the temperature is within a certain temperature range, a greater impregnating agent flow rate is selected than when the temperature is outside or outside this temperature range. The temperature range is preferably selected so that it encompasses the temperature at which the impregnating agent has its lowest viscosity. The temperature range is delimited by a lower temperature limit towards the lower temperature and an upper temperature limit towards the higher temperature. For example, the temperature at which the lowest viscosity is reached may be included in the middle of the temperature range, or the temperature at which the lowest viscosity is reached may define the temperature range, in particular towards the higher temperature. In the former case, the temperature is midway between the temperature limits, while in the latter case, the temperature corresponds to one of the temperature limits.

[0030] If the actual temperature of the wire winding is outside the temperature range, i.e., if it is greater than the upper temperature limit or less than the lower temperature limit, then a higher viscosity of the impregnant is assumed. The impregnant flow rate is selected accordingly. Preferably, the further the temperature exceeds or is outside the temperature range, the smaller the impregnant flow rate is selected. Furthermore, it is preferred to select a smaller impregnant flow rate or reduce the impregnant flow rate more significantly when the temperature is above the temperature range than when the temperature is below the temperature range. The described method allows for the impregnant to be introduced into the groove as required, thereby ensuring, in particular, that the groove is reliably filled with the impregnant.

[0031] A refinement of the present invention provides that the temperature of at least one wire winding is increased from a starting temperature to a first temperature, during which the impregnating agent flow rate is at least temporarily increased. The starting temperature is understood to be the temperature of the wire winding at the start of, or immediately before, the introduction of the impregnating agent into the groove. For example, the starting temperature is selected such that the viscosity of the impregnating agent is at most 50%, at most 30%, or at most 10% greater than the minimum viscosity of the impregnating agent during its introduction into the groove. In this respect, the starting temperature is already above the ambient temperature of the device for producing the component.

[0032] For example, the wire winding is brought to a starting temperature by preheating, in particular also by energizing the wire winding, specifically before introducing the impregnating agent into the groove. For example, once the temperature of the wire winding reaches the starting temperature, the impregnating agent is introduced. While the impregnating agent is introduced into the groove, preferably during a first period, the temperature of the wire winding is increased from the starting temperature toward the first temperature, in particular to the first temperature. During this period, the impregnating agent flow rate is also increased. For example, when the temperature corresponds to the starting temperature, the impregnating agent flow rate is set to the starting flow rate. The impregnating agent flow rate is increased from the starting flow rate toward the first flow rate.

[0033] It can be provided that the impregnating agent flow rate already corresponds to the first impregnating agent flow rate before the temperature reaches the first temperature. However, it can also be provided that the impregnating agent flow rate reaches the first flow rate only when the temperature corresponds to or reaches the first temperature. Preferably, the starting temperature and the first temperature lie within the already mentioned first temperature range, in which the viscosity of the impregnating agent is relatively low. For example, the starting temperature delimits the first temperature range towards lower temperatures, while the first temperature delimits the first temperature range towards higher temperatures. In each case, the method allows for reliable introduction of the impregnating agent into the recess, particularly while avoiding cavities.

[0034] A refinement of the present invention provides that the impregnating agent flow rate is at least temporarily reduced while the temperature of at least one wire winding is increasing from a first temperature to a second temperature. Preferably, the temperature is increased from the first temperature to the second temperature, in particular during a second time period following the first time period. In this context, at the beginning of the second time period, the temperature corresponds to the first temperature, and at the end of the second time period, the temperature corresponds to the second temperature.

[0035] During the temperature increase, i.e., during the second period, the impregnating agent flow rate is at least temporarily reduced. For example, the impregnating agent flow rate corresponds to the first flow rate at the beginning of the second period and to a second flow rate that is smaller than the first flow rate at the end of the second period. Provision can be made for the impregnating agent flow rate to already correspond to the second flow rate before the end of the second period and to remain at this second flow rate until the end of the second period.

[0036] For example, the impregnating agent flow rate reaches the second flow rate after at least 20%, at least 40%, or at least 60%, and / or at most 90%, at most 80%, or at most 70% of the second period has elapsed. By increasing the temperature to the second temperature, the viscosity of the impregnating agent increases, and in particular, gelling of the impregnating agent begins. Because impregnating agent is also introduced into the groove during the second period, reliable filling of the groove with impregnating agent is ensured, and the formation of cavities is avoided.

[0037] A refinement of the present invention provides that the temperature of at least one wire winding is adjusted from the second temperature to a final temperature, and during this time the impregnating agent flow rate is at least temporarily reduced. The final temperature is the temperature of the wire winding at the end of the impregnating agent introduction into the groove, i.e., at the end of the impregnating agent supply into the groove. It can be provided that the final temperature corresponds to the second temperature. Alternatively, the final temperature is greater than the second temperature.

[0038] The temperature adjustment from the second temperature to the final temperature occurs during a third period. At the beginning of the third period, the temperature corresponds to the second temperature, and at the end of the third period, the temperature corresponds to the final temperature. Preferably, at the end of the third period, the introduction of the impregnating agent into the groove is stopped, i.e., the impregnating agent flow rate is reduced to zero. Preferably, at the beginning of the third period, the impregnating agent flow rate corresponds to the second flow rate or to another second flow rate that is lower than the second flow rate. Thus, provision can be made for the impregnating agent flow rate to be reduced, in particular abruptly, at the end of the second period or at the beginning of the third period.

[0039] During the third period, the impregnating agent flow rate is at least temporarily reduced, in particular from the second flow rate or another second flow rate to the third flow rate. This allows for the impregnating agent to solidify, in particular by gelling, during the third period. However, the impregnating agent continues to be introduced into the groove to ensure complete filling of the groove. This method achieves a particularly high degree of filling of the groove with the impregnating agent.

[0040] A refinement of the present invention provides that, after reaching the final temperature, the temperature of at least one wire winding is kept constant for a specific period of time, in particular a period of time selected based on the final temperature. This period of time can also be referred to as a fourth period of time. During the fourth period of time, the impregnating agent completely cures, and the length of this period of time is in particular selected so that the impregnating agent completely cures or gels. During this period of time, the temperature of the wire winding is kept constant, in particular at the final temperature. This period of time, or more precisely its length, is preferably selected based on the final temperature, since the rate at which the impregnating agent cures is temperature-dependent. The higher the temperature, the shorter the period of time can be selected, and vice versa. By selecting the period of time according to the requirements, the shortest possible cycle times can be achieved when manufacturing the component.

[0041] A refinement of the invention provides that the temperature of at least one wire winding is regulated according to a predetermined temperature profile, and the impregnating agent flow rate is regulated according to a predetermined flow rate profile, wherein the temperature profile and the flow rate profile are determined as a function of the impregnating agent and / or as a function of the component geometry. A temperature profile is to be understood as a curve of the temperature over time, and a flow rate profile is to be understood as a curve of the impregnating agent flow rate over time.

[0042] Before the impregnating agent is introduced into the groove, the temperature and flow rate profiles are determined and subsequently implemented over time. Thus, during the introduction of the impregnating agent into the groove, the temperature of the wire winding is regulated according to the temperature profile, and the impregnating agent flow rate is regulated according to the flow rate profile. To adapt the impregnating agent to the component and the impregnating agent, the temperature and flow rate profiles are determined and specified based on the impregnating agent and / or the component, more specifically, the component geometry. The use of the profiles enables particularly short cycle times during component production, while achieving the advantages already mentioned.

[0043] A refinement of the present invention provides that the total amount of impregnating agent in the at least one groove is determined based on an inflow rate of impregnating agent into the at least one groove and an outflow rate of impregnating agent out of the at least one groove, and the temperature and / or impregnating agent flow rate are selected based on this total amount. The inflow rate is determined, in particular, based on the amount of impregnating agent introduced into the groove per unit time. For example, the inflow rate corresponds to the amount of impregnating agent applied from the at least one nozzle.

[0044] In addition, the discharge amount, preferably the amount of impregnating agent discharged from the groove per unit time, is detected. The difference between the discharge amount and the discharge amount provides the amount of impregnating agent remaining in the groove. For example, it is provided that the temperature is increased from a first temperature to a second temperature as soon as the total amount of impregnating agent exceeds a threshold value, i.e., is greater than a threshold value. This ensures that the impregnating agent cures only when the groove is completely or at least nearly completely filled with impregnating agent. Furthermore, it can be provided that the impregnating agent flow rate is selected to be smaller as the total amount approaches the threshold value, in order to reduce impregnating agent consumption. The advantages already mentioned are achieved by the described method.

[0045] A refinement of the invention provides that, after the impregnating agent has been introduced into the at least one groove, the temperature of the at least one wire winding is regulated by an external heating device. This is performed in particular during the aforementioned fourth time period, during which the impregnating agent cures. It may be provided that, in addition to applying current to the wire winding, the external heating device is also used for temperature regulation.

[0046] However, it is particularly preferred to stop applying current to the wire winding and maintain the temperature of the wire winding using an external heating device. This ensures that the impregnating agent cures completely. For example, an oven can be used as the external heating device, in which the component is arranged. The longitudinal center axis of the component is preferably aligned so that it remains in the same direction both during heating of the component by the external heating device and during the introduction of the impregnating agent. This in turn ensures uniform curing of the impregnating agent.

[0047] Additionally or alternatively, an external heating device or another external heating device can also be used to preheat the component. During preheating, the temperature of the component is increased before the impregnating agent is introduced into the groove. For example, during preheating, the component is preheated to a first temperature, so that the energy required to subsequently adjust the temperature of the wire winding to the first temperature by energizing the wire winding is lower.

[0048] A refinement of the present invention provides that the impregnating agent for introduction into the at least one groove is applied by at least one nozzle that is at least temporarily displaced relative to the component. The use of a nozzle for applying the impregnating agent, or more precisely, for introducing the impregnating agent into the groove, has already been mentioned. The nozzle is temporarily displaced relative to the component, in particular also during the introduction of the impregnating agent into the groove. For example, the nozzle is displaced over the groove according to a movement path, which is, for example, circular. The nozzle is displaced in such a manner that the impregnating agent is introduced into the groove in a uniformly distributed manner, or more precisely, is introduced in such a manner that the impregnating agent is evenly distributed in the groove.

[0049] The present invention also relates to a device for producing a component for an electric machine, in particular for carrying out a method according to the embodiments described herein, wherein the component comprises a magnetic core having at least one groove, the at least one groove accommodating at least one wire winding, extending parallel to the longitudinal center axis of the component and completely penetrating the magnetic core, and wherein the device is arranged and designed such that, during the introduction of an impregnating agent into the at least one groove, the component is oriented such that the impregnating agent enters the at least one groove under the influence of gravity in the direction of the longitudinal center axis.

[0050] Here, the device is further configured and designed to adjust the temperature of the at least one wire winding first to a lower first temperature selected to reduce the viscosity of the impregnating agent and then to a higher second temperature selected to increase the viscosity of the impregnating agent by applying an electric current during the introduction of the impregnating agent into the at least one groove.

[0051] The advantages of this embodiment of a device or method for producing a component for an electric machine have already been pointed out. Both the device and its operating method can be improved according to the embodiments in this description, so that reference is made to these embodiments in this respect.

[0052] The features and feature combinations described in the description, in particular the features and feature combinations described in the following description of the figures and / or shown in the figures, can be used not only in the respectively indicated combination but also in other combinations or alone without departing from the scope of the present invention. Therefore, embodiments that are not explicitly shown or described in the description and / or the figures, but which are derived from or can be derived from the described embodiments, are also to be considered as included in the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The invention is explained in greater detail below with reference to exemplary embodiments shown in the drawings, without however being restricted thereto.

[0054] in:

[0055] Figure 1 shows a schematic illustration of a device for producing a component for an electric machine and a component,

[0056] Figure 2 shows a schematic cross-sectional illustration of components for an electric machine, and

[0057] Figure 3 Two graphs are shown in which the temperature curve and the impregnating agent flow rate are each plotted as an example over time.

[0058] Reference Signs List

[0059] 1 device

[0060] 2 Components

[0061] 3 nozzles

[0062] 4 cores

[0063] 5-axis

[0064] 6 Rotation axis

[0065] 7 grooves

[0066] 8 Wire winding

[0067] 9 Winding head

[0068] 10 magnetic poles

[0069] 11 Matrix

[0070] 12 pole shoes

[0071] 13 Coolant channels

[0072] 14 Curve

[0073] 15 Curve DETAILED DESCRIPTION

[0074] Figure 1 A schematic diagram shows an apparatus 1 for producing a component 2 for an electric motor (not shown in further detail). The apparatus is shown only with at least one nozzle 3 (here: a plurality of nozzles 3), by means of which an impregnating agent can be applied toward the component 2. Component 2 is, by way of example only, the rotor of the electric motor. It has a magnetic core 4, which is arranged on a shaft 5 of the electric motor and is mounted so as to be rotatable together with the shaft about an axis of rotation 6.

[0075] A plurality of grooves 7, of which only some are marked here by way of example, are made in the magnetic core 4. At least one wire winding 8 is accommodated in the groove 7. An embodiment is shown in which there are a plurality of grooves 7, in which a plurality of wire windings 8 are arranged accordingly. The wire windings 8 form winding heads 9 on the end sides of the magnetic core 4 so that they protrude beyond the magnetic core 4 when viewed in the axial direction with respect to the axis of rotation 6. Preferably, extrusion bodies, not shown here, are also arranged in the grooves 7. The extrusion bodies serve to separate the wire windings 8 arranged in the same groove 7 in the circumferential direction. The extrusion bodies serve to reliably hold the wire windings 8 in the circumferential direction. Preferably, the extrusion bodies are made of a non-magnetic and / or non-magnetizable material, for example plastic.

[0076] The impregnating agent is introduced into the groove 7 of the magnetic core 4 by means of at least one nozzle 3. For this purpose, the component 2 is oriented vertically, that is, its longitudinal center axis, which here coincides with the axis of rotation 6, is oriented vertically. This means that the longitudinal center axis runs parallel to the gravity vector or perpendicular to an imaginary plane, which in turn is perpendicular to the gravity vector.

[0077] Figure 2 A schematic cross-sectional view of a component 2 is shown. A magnetic core 4 can be seen, which has a plurality of magnetic poles 10, which extend radially outward from a base body 11 relative to the axis of rotation 6. The magnetic poles 10 each have a pole shoe 12 on their outer side in the radial direction, in the region of which the poles widen in the circumferential direction. Both the magnetic poles 10 and the pole shoes 12 are arranged spaced apart from each other in the circumferential direction, i.e., do not touch each other. The extrusion bodies already mentioned are engaged in particular between the magnetic poles 10, preferably also between the pole shoes 12. In this regard, the extrusion bodies are arranged between adjacent magnetic poles 10 and / or between adjacent pole shoes 12, viewed in the circumferential direction. The extrusion bodies abut the pole shoes 12 in particular on two opposite sides in the circumferential direction.

[0078] The magnetic poles 10 delimit grooves 7 in the circumferential direction, in which wire windings 8 are arranged. In particular, each of the magnetic poles 10 is assigned such a wire winding 8, or more precisely, each of the magnetic poles 10 is surrounded by such a wire winding, so that each of the wire windings 8 is located in a groove 7 delimited by the same magnetic pole 10. It can be seen that a plurality of coolant channels 13 are additionally produced in the magnetic core 4, in particular in the base body 11, only some of which are shown as examples.

[0079] Figure 3Two graphs are shown, in which the temperature and the impregnating agent flow rate varying with time are plotted, that is, the temperature is plotted as curve 14 and the impregnating agent flow rate is plotted as curve 15. A plurality of moments t0, t1, t2, and t3 are shown, where t0 ≤ t < t1 is the first period, t1 ≤ t < t2 is the second period, t2 ≤ t < t3 is the third period, and t ≥ t3 is the fourth period. The temperature shown as curve 14 is the actual temperature of the wire winding 8, which is adjusted by energizing the wire winding 8. For example, it is stipulated that the actual temperature of the wire winding 8 is measured or calculated, and the current intensity and / or voltage of the current supplied to the wire winding 8 are adjusted so that the actual temperature of the wire winding 8 is adjusted to the target temperature.

[0080] The impregnating agent flow rate of curve 15 illustrates the flow rate of the impregnating agent introduced into the groove 7 of the magnetic core 4. At the start of the first period, that is, at moment t0, the temperature corresponds to the starting temperature, and the impregnating agent flow rate corresponds to the initial flow rate. During the first period, the temperature rises to the first temperature. Additionally, the flow rate rises to the first flow rate. During the second period, the temperature further rises from the first temperature to the second temperature, while the flow rate decreases from the first flow rate to the second flow rate.

[0081] In the third period, the temperature is adjusted from the second temperature to the final temperature, where, in the illustrated embodiment, the final temperature corresponds to the second temperature. Additionally, during the third period, the flow rate decreases from the second flow rate, that is, it decreases to a final flow rate, for example, equal to zero. In the fourth period, the temperature of the wire winding 8 is maintained at the final temperature, however, the impregnating agent is no longer introduced into the groove 7.

[0082] During the first period, the temperature of the wire winding 8 is selected such that the viscosity of the impregnating agent is as low as possible. During the second period, the temperature of the wire winding 7 is raised, specifically, to a temperature at which the impregnating agent begins to cure, especially the impregnating agent begins to gelatinize. This temperature is maintained during the third period to achieve continuous curing of the impregnating agent. During the fourth period, the temperature of the wire winding 8 is maintained, for example, by means of an external heating device until the impregnating agent is completely hardened.

[0083] Using the described method for manufacturing the component 2 for an electric machine, a high degree of filling of the groove 7 with the impregnating agent is achieved by combining different measures. On the one hand, the longitudinal central axis of the component 2 is vertically oriented, so that the impregnating agent is affected by gravity, especially only by gravity, and is forced to pass through or be conveyed through the groove 7 along the axial direction based on the longitudinal central axis. On the other hand, the desired temperature is achieved simply by energizing the wire winding 8. The temperature of the wire winding 8 and the impregnating agent flow rate are also selected such that, first, it is ensured that the impregnating agent is completely introduced into the groove 7, and then the curing of the impregnating agent is achieved while keeping the impregnating agent in the groove 7.

Claims

1. A method for producing a component (2) for an electric machine, wherein: The component (2) has a magnetic core (4) having at least one groove (7) which accommodates at least one wire winding (8), extends parallel to the longitudinal center axis of the component (2) and completely penetrates the magnetic core (4), wherein, during the introduction of the impregnating agent into the at least one groove (7), the component (2) is oriented such that the impregnating agent enters the at least one groove (7) in the direction of the longitudinal center axis under the influence of gravity, and is characterized in that, by applying an electric current during the introduction of the impregnating agent into the at least one groove (7), the temperature of the at least one wire winding (8) is first adjusted to a lower first temperature selected to reduce the viscosity of the impregnating agent and then to a higher second temperature selected to increase the viscosity of the impregnating agent.

2. The method according to claim 1, characterized in that The temperature of the at least one wire winding (8) is regulated by regulating the current intensity and / or the voltage of the current flowing through the at least one wire winding (8).

3. The method according to any one of the preceding claims, characterized in that The impregnating agent is introduced into the at least one groove (7) at an impregnating agent flow rate that is selected as a function of the temperature of the at least one wire winding (8).

4. The method according to any one of the preceding claims, characterized in that The temperature of the at least one wire winding (8) is increased from a starting temperature to a first temperature, and during this the impregnating agent flow rate is at least temporarily increased.

5. The method according to any one of the preceding claims, characterized in that During the temperature increase of the at least one wire winding (8) from the first temperature in the direction of the second temperature, the impregnating agent flow is at least temporarily reduced.

6. The method according to any one of the preceding claims, characterized in that The temperature of the at least one wire winding (8) is adjusted starting from the second temperature towards a final temperature, and during this the impregnating agent flow is at least temporarily reduced.

7. The method according to any one of the preceding claims, characterized in that After reaching the final temperature, the temperature of the at least one wire winding (8) is kept constant for a determined period of time.

8. The method according to any one of the preceding claims, characterized in that The temperature of the at least one wire winding (8) is adjusted according to a predetermined temperature profile, and the impregnating agent flow rate is adjusted according to a predetermined flow rate profile, wherein the temperature profile and the flow rate profile are determined according to the geometric configuration of the impregnating agent and / or the component (2).

9. The method according to any one of the preceding claims, characterized in that An impregnating agent is applied for introduction into the at least one groove (7) by means of at least one nozzle (3) which is at least temporarily displaced relative to the component (2).

10. Device (1) for producing a component (2) for an electric machine, in particular for carrying out the method according to one or more of the preceding claims, wherein: The component (2) has a magnetic core (4) having at least one groove (7) which accommodates at least one wire winding (8), extends parallel to the longitudinal center axis of the component (2) and completely penetrates the magnetic core (4), wherein the device (1) is arranged and designed to orient the component (2) during the introduction of the impregnating agent into the at least one groove (7) so that the impregnating agent enters the at least one groove (7) in the direction of the longitudinal center axis due to the influence of gravity, and is characterized in that the device (1) is also arranged and designed to adjust the temperature of the at least one wire winding (8) first to a lower first temperature selected to reduce the viscosity of the impregnating agent and then to a higher second temperature selected to increase the viscosity of the impregnating agent by applying an electric current during the introduction of the impregnating agent into the at least one groove (7).

Images