WO2016193472A1

WO2016193472A1 - Dc fan motor and heating, ventilation and/or air-conditioning system module

Info

Publication number: WO2016193472A1
Application number: PCT/EP2016/062716
Authority: WO
Inventors: Falko BUSCH
Original assignee: Valeo Klimasysteme Gmbh
Priority date: 2015-06-05
Filing date: 2016-06-03
Publication date: 2016-12-08
Also published as: DE102015108903A1

Abstract

A DC fan motor (10) for a heating, ventilation and/or air-conditioning system module of a motor vehicle is described, comprising a rotor (14) and a stator (12). The stator (12) has at least one stator winding (16) which in the energized state generates an electromagnetic stator field which interacts with the rotor (14) in order to cause the latter to perform a rotational motion. Preferably, provision is made of a continuously variable power regulation (18) comprising at least one resistor (20) having a variable resistance value. The power regulation (18) is electrically coupled to the at least one stator winding (16) in order to vary the current flow through the stator winding (16). Furthermore, a heating, ventilation and/or air-conditioning system module for a motor vehicle is described.

Description

DC FAN MOTOR AND HEATING, VENTILATION AND/OR AIR- CONDITIONING SYSTEM MODULE

The invention relates to a DC fan motor for a heating, ventilation and/or air-conditioning system module and to a heating , ventilation and/or air-conditioning system module for a motor vehicle .

Various heating, ventilation and/or air-conditioning system modules ( for short : HVAC modules ) having a fan motor and a fan impeller driven by the fan motor are known from the prior art . The fan motor may be operated in such a way that air is drawn in and interacts with a heat exchanger of the HVAC module in order to be cooled . Furthermore , the fan motor may be operated in such a way that the fan impeller functions as a fan . Various embodiments are known for the fan motors used, wherein provision is typically made of a rotor and a stator which interact .

The prior art discloses fan motors in which the stator has permanent magnets and interacts with a rotor magnetic field generated by means of a rotor winding provided on the rotor . The fan motors furthermore have a commutator which correspondingly reverses the polarity of the rotor magnetic field generated by energization . The commutators are usually formed by means of brushes , which is why the term brush motors is also used . The power of the fan motors embodied as brush motors is controlled via the motor magnetic field generated by energization by means of series-connected electrical resistors being connected in or disconnected in order to change the voltage supply of the rotor windings and thus the rotor current flowing through the rotor windings . This results in a stepwise power regulation of the fan motor . On account of the series resistors , however, high power losses occur which correspondingly reduce the efficiency of the fan motor since a high current flows in the driving of the rotor . The high power losses occur primarily if the fan motor is operated in a lower or medium power range in which a plurality of resistors are connected in .

Furthermore , the prior art discloses fan motors in which the rotor has permanent magnets which generate the rotor magnetic field which interacts with a stator magnetic field formed by means of energized stator windings . The stator windings are driven by means of a control in such a way that a rotating stator field is brought about which exerts an angular momentum on the rotor with its static rotor field . These fan motors are also referred to as brushless motors since no commutator is provided.

The power control of the brushless fan motors is performed by means of a so-called PWM control (pulse width modulation) in order to generate the rotating stator field . In this case , the fan motor is driven in a pulsed manner with a constant voltage, via the pulse width of which the power can be set . PWM control constitutes an efficiency-optimized control , which is complex and expensive , however . In an HVAC module , the power of the fan motor is furthermore intended to be dependent on the temperature, and so an additional temperature regulation has to be provided . In this case , the power of the fan motor is usually controlled depending on the temperature of a medium, said temperature being detected by the temperature regulation . The medium may be air or a fluid, for example a coolant or heating agent . The temperature regulation is coupled to the PWM control or the power control having the plurality of switchable resistors and communicates a temperature- dependent driving signal . On account of the driving signal , the pulse width of the PWM driving is varied or resistors are connected in or disconnected .

It has proved to be disadvantageous that the power regulation of a fan motor has a low efficiency or is complex and expensive .

It is an obj ect of the invention to provide a fan motor and a heating, ventilation and/or air-conditioning system module having a simple construction and also a simple, efficient and cost-effective power regulation .

The obj ect of the invention is achieved by means of a DC fan motor for a heating , ventilation and/or air- conditioning system module of a motor vehicle , comprising a rotor and a stator having at least one stator winding which in the energized state generates an electromagnetic stator field which interacts with the rotor in order to cause the latter to perform a rotational motion, wherein provision is made of a preferably continuously variable power regulation comprising at least one resistor having a variable resistance value , wherein the power regulation is electrically coupled to the at least one stator winding in order to vary the current flow through the stator winding .

The basic concept of the invention is to provide a simply constructed fan motor having a power regulation which is integrated in the control and which regulates the voltage present at the at least one stator winding . The efficiency of the fan motor is high since no resistors are provided which are connected to the rotor winding . As a result , the power regulation can be embodied as continuously variable . The power of the fan motor may be regulated via the variable resistor, for which reason an expensive PWM control can be dispensed with, the efficiency of which is nevertheless achievable since the generated stator field is varied . One aspect provides for a change in the resistance value to vary the current intensity of the current flowing through the at least one stator winding and hence the strength of the electromagnetic stator field . Since the electromagnetic stator field is generated by energization of the stator winding , it is directly dependent on the current intensity . The power of the DC fan motor can thus be regulated via the resistor .

In accordance with a further aspect , the power regulation exclusively consists of the at least one resistor . As a result , a particularly simply constructed power regulation is formed which requires no further electronics . The at least one stator winding of the stator may be directly coupled to a voltage source , wherein only the variable resistor may be provided between the voltage source and the stator winding . The control may then be , in its simplest form, a switch which switches the voltage .

The at least one stator winding may preferably be supplied with a voltage by the electrical system of the motor vehicle . In particular, the resistor is a thermistor, the resistance value of which changes depending on its temperature . The power regulation thus corresponds to an automatic temperature regulation which is integrated in the control . The power of the DC fan motor which is available is directly dependent on a temperature detected by the resistor . The variable resistor may accordingly be a temperature sensor . The thermistor generally has a significant variation of its resistance value if the temperature changes , for example at least a resistance value change of approximately 5% in the case of temperature variation of 10°C .

In accordance with one aspect , the thermistor is arranged in a region around which a medium flows , or at a section through which a medium flows , such that the DC fan motor itself regulates its power depending on the temperature of the medium . An appropriate medium is , inter alia , a fluid in a circuit of the HVAC module . This may be for example a coolant in a cool ing circuit , in particular air, a cooling liquid, oil , a refrigerant or water . Alternatively, the circuit may also be used for warming up or heating, such that the fluid is a heating agent . Furthermore , the medium may be air drawn in from the vehicle interior or air released into the vehicle interior . In this case , the thermistor may be arranged directly in the air flow of the corresponding air, such that the power of the DC fan motor is regulated depending on the air temperature .

Depending on the location at which the thermistor is arranged, it is ensured that the power of the DC fan motor is regulated depending on the temperature of the corresponding medium .

In particular, the thermistor may be a PTC or NTC thermistor . These thermistors are also referred to as positive temperature coefficient thermistor ( PTC thermistor) or as negative temperature coefficient thermistor (NTC thermistor) , the resistance value of which increases and decreases , respectively, with increasing temperature . The choice of the type depends on the field of use of the DC fan motor, the arrangement of the resistor and the medium to whose temperature the resistor is exposed .

In accordance with a further aspect of the invention, the resistor may be a manually adjustable potentiometer . This makes it possible for the power regulation of the DC fan motor to be performed manually .

In particular, the rotor has at least one rotor pole with an electrical rotor winding which, upon current flowing through, generates an electromagnetic rotor field which interacts with the electromagnetic stator field . The DC fan motor is thus embodied as a brush motor. A particularly cost-effective embodiment of a DC fan motor is provided thereby .

One aspect of the invention provides for the stator and the rotor to be electrically connected in parallel , that is to say that the DC fan motor is a shunt-wound motor . The at least one stator winding and the at least one rotor winding are connected to the same voltage source, for example a voltage source of the electrical system of the vehicle . The stator current that flows through the at least one stator winding is accordingly limited only by the ohmic resistance of the stator winding itself . In the case of a shunt-wound motor the rotational speed of a fan impeller coupled to the DC fan motor may be regulated directly in a simple manner by means of the power regulation of the electromagnetic stator field .

Alternatively, the DC fan motor may be embodied as a separately excited electric motor in which the stator winding and the rotor winding are connected to different voltage sources .

Furthermore , the invention relates to a heating, ventilation and/or air-conditioning system module (HVAC module) for a motor vehicle, comprising at least one fan impeller and a DC fan motor of the abovementioned type which drives the fan impeller . This affords an efficient and cost-effective possibility of implementing an HVAC module in which the power regulation is performed automatically. An expensive and separately implemented power regulation is not necessary . In particular, the at least one resistor is a thermistor arranged in the HVAC module . The thermistor thus reacts to a temperature in a region or a section of the HVAC module , wherein the power of the DC fan motor and the rotational speed of the fan impeller are correspondingly regulated automatically depending on said temperature .

In accordance with a further aspect the resistor is arranged in a region around which a medium flows or at a section through which a medium flows in the HVAC module . In particular, the medium may be a fluid such as a coolant flowing through an air-conditioning circuit . An appropriate coolant is air, a cooling liquid, oil , a refrigerant and/or water . The thermi stor may thus regulate the power directly on the basis of the temperature of the coolant if the thermistor is arranged for example on a tube through which the coolant flows .

Furthermore , the thermistor may also be arranged in a region of the HVAC module in which the fluid flows directly around it , for example within a tube of the HVAC module through which the fluid flows .

If the thermistor is intended to regulate the power of the HVAC module on the basis of the air temperature of the vehicle interior , then the resistor can be arranged in a region of the HVAC module around which air flows . This may involve the air drawn in from the vehicle interior or the air released again to the vehicle interior after having previously been cooled or heated . The HVAC module itself regulates its power depending on the temperature of the medium, in particular the flow rate drawn in by the fan impeller . The power of the HVAC module comprises the power of its DC fan motor and the rotational speed of its fan impeller . Various combinations can be used, for example a small DC fan motor with a large fan impeller, or a large DC fan motor with a small fan impeller . This depends on the field of use of the HVAC module . If the HVAC module draws in a quantity of air via the fan impeller, the flow rate drawn in is correspondingly regulated in a temperature-dependent manner .

A further aspect provides for the thermistor to be arranged in or at a heat exchanger of the HVAC modu1e , around which or through which heat exchanger flows an air flow directed in the vehicle interior . As a result , the power may be regulated on the basis of a mixed temperature (air temperature and the temperature of the coolant ) . In this case , different influences of the corresponding temperatures arise depending on the exact arrangement of the thermistor .

Furthermore , the temperature of the coolant in the heat exchanger may be measured at a location after the coolant has already cooled the air to be cooled or before the coolant cools the air to be cooled .

Depending on the exact location at which the thermi stor is arranged, this results in different requirements made of the resistor with regard to its temperature sensitivity or the temperature range intended to be covered by the resistor . Further advantages and properties of the invention are evident from the following description and the drawings , to which reference is made . In the drawings : - Figure 1 shows a schematic illustration of a DC fan motor according to the invention,

Figure 2 shows a schematic illustration of a heating , ventilation and/or air-conditioning system module according to the invention (HVAC module) , - Figure 3 shows a schematic equivalent circuit diagram for the DC fan motor according to the invention, - Figure 4 shows a diagram showing the rotational speed versus the torque of two fan impellers and of a DC fan motor according to the invention for different magnetic fluxes ,

Figure 5 shows a further diagram showing the rotational speed versus the torque of a fan impeller and of a DC fan motor according to the invention for various magnetic fluxes , Figure 6 shows a diagram showing the energy consumption versus the resistance of the power regulation for a DC fan motor according to the invention and a fan motor from the prior art , and

Figure 7 shows a diagram showing the annual operating time of a fan motor over a year as a function of the speed of the fan motor .

Figure 1 schematically shows a DC fan motor 10 that can be used for a heating , ventilation and/or air- conditioning system module ( for short : HVAC module) of a motor vehicle . The term fan motor is used in an abbreviatory way in the following description .

The fan motor 10 has a stator 12 and a rotor 14 , which can rotate about a rotation axis D if it is driven accordingly . In the embodiment shown, the stator 12 has a schematically illustrated stator winding 16 , which is representative of a plurality of stator windings 16 that the stator 12 may have . The at least one stator winding 16 is electrically coupled to a power regulation 18 which is situated on a circuit board and which is part of a system for driving the fan motor 10. The power regulation 18 comprises a resistor 20 having a variable resistance value . By means of the power regulation 18 , a current that flows through the at least one stator winding 16 of the stator 12 is regulated in order to generate an electromagnetic stator field . The electromagnetic stator field interacts with an electromagnetic rotor field of the rotor 14, as a result of which the rotor 14 is caused to perform rotary motion . The rotor field may be generated by means of at least one rotor winding (not illustrated here) , wherein a commutator is provided via which the polarity reversal of the rotor field is performed . The fan motor 10 may thus be embodied as a brush motor .

The power regulation 18 sets the current flowing through the at least one stator winding 16 in a continuously variable manner if the resistance value of the variable resistor 20 may vary in a continuously variable manner .

By way of example , the variable resistor 20 may be a thermistor, in particular a PTC or NTC thermistor which changes with the temperature in a continuously variable manner .

If the variable resistor 20 is embodied as a PTC or NTC thermistor, that is to say as a positive temperature coefficient or negative temperature coefficient thermistor, a higher or respectively lower resistance value arises when the temperature to which the resistor 20 is exposed rises . The changed resistance value results in a variation of the voltage present at the stator winding 16 and thus in a variation of the current intensity of the current flowing through the stator winding 16. This in turn affects the generated electromagnetic stator field which is used for driving the rotor 14. A change in the stator field accordingly brings about a change in the power of the fan motor 10 , as a result of which a continuously variable, automatic and temperature- dependent power regulation is provided .

Alternatively, the resistor 20 may be a manually adjustable potentiometer, such that the power regulation 18 , although implemented in a continuously variable manner, is implemented manually.

In the embodiment shown, the fan motor 10 is embodied as an internal rotor since the stator 12 surrounds the rotor 14. Alternatively, the fan motor 10 may also be embodied as an external rotor, such that the rotor 14 radially surrounds the stator 12.

The fan motor 10 may generally be used in a heating , ventilation and/or air-conditioning system module 22 for a motor vehicle , this module being designated hereinafter as HVAC module 22. Such a HVAC module 22 is shown schematically in Figure 2.

The HVAC module 22 comprises a fan impeller 24 , which is mechanically coupled to the fan motor 10 and is driven by the fan motor 10. is clear from Figure 2 that the power exclusively consists of the variable resistor 20 , which is arranged at a heat exchanger 26 of the HVAC module 22 in the embodiment shown .

Accordingly, it is possible to dispense with further electronic components for implementing the power regulation 18 , as a result of which a cost-effective and simply constructed fan motor 10 is provided .

The variable resistor 20 may be arranged directly on an outer said of a tube of the heat exchanger 26 through which a medium flows . The medium is for example a coolant or a heating agent if the heat exchanger 26 is used for heating air . An appropriate medium is , in particular, air, a cooling or heating liquid, oil , a refrigerant and/or water .

The power of the HVAC module 22 is regulated in a temperature-dependent manner automatically and independently since the variable resistor 20 or the power regulation 18 detects the temperature at the heat exchanger 26. Proceeding from the current flowing through the stator winding 16 , the rotational speed of the fan impeller 24 is correspondingly regulated automatically and independently .

The resistor 20 arranged on the tube of the heat exchanger 26 detects the temperature of the fluid flowing through the tube . The variable resistor 20 or the power regulation 18 may be embodied in such a way that the resistance value rises at an increased temperature of the fluid, as a result of which a lower voltage is present at the stator winding 16. This results in a lower stator current I_s in the stator winding 16 , as a result of which the generated electrotnagnetic stator field is weaker and the magnetic flux Φ decreases . The weaker magnetic flux Φ influences the power of the fan motor 10 , in particular the rotational speed n . Depending on the combination of the fan impeller 24 and the fan motor 10 , this may have the effect that the fan impeller 24 arranged on the rotor 14 rotates more rapidly . In the case of a different fan impeller 24 , the described variation of the magnetic flux Φ may have the effect that the fan impeller 24 rotates more slowly.

Furthermore a resistor 20 may be provided, the resistance value of which decreases at an increased temperature of the fluid . As a result , a higher voltage would be present at the stator winding 16 , as a result of which a higher stator current I_s flows , resulting in a stronger stator field and a higher magnetic flux Φ. A lower or higher rotational speed n thus results depending on the chosen fan impeller 24.

Alternatively, the variable resistor 20 may be arranged in a region of the HVAC module 22 around which air flows . By way of example , the HVAC module 22 may merely be a ventilation module in which no heat exchanger sections are provided . In this case, the power of the HVAC module 22 , that is to say the power of the fan motor 10 and the rotational speed of the fan impeller 24 , is regulated depending on the air temperature drawn in or the air temperature released into the vehicle compartment . In this embodiment variant , the medium is the air which is drawn in from the vehicle interior or which is released to the vehicle interior . In a further alternative embodiment, the thermistor 20 may be arranged in a tube of the HVAC module 22 , in particular of the heat exchanger 26 , as a result of which the fluid flowing in the tube flows around the thermistor 20 , such that heat transfer losses of the tube are avoided .

Figure 3 schematically illustrates an equivalent circuit diagram of the fan motor 10 , from which it is clear that the fan motor 10 is embodied as a separately excited motor . If the voltage U_s applied to the circuit of the stator 12 and the voltage U_a applied to the circuit of the rotor 14 are assigned to the same voltage source , a shunt-wound motor is involved in which the stator 12 and the rotor 14 are electrically connected in parallel .

The voltage U_s is present at the stator 12 , wherein the stator current I_s flowing through the stator windings 16 generates the electromagnetic stator field . In this case, a magnetic flux Φ which interacts with the electromagnetic rotor field in order to drive the rotor 14 and induces a voltage U_ind in the circuit of the rotor 14. In the rotor 14 itself a rotor current I_a flows which is dependent on the applied voltage U_a and the induced voltage U_ind. The stator 12 and the rotor 14 in each case have internal resistances R_s, R_a, wherein the stator 12 additionally has the variable resistor 20.

The magnetic flux density or the magnetic flux Φ is linearly proportional to the stator current I_s that flows through the at least one stator winding 16 , which generally means that the magnetic flux Φ decreases with decreasing stator current I_s if the resistance value of the resistor 20 rises , since a lower voltage is then present at the stator winding 16. The rotational speed n of the rotor 14 results from the known formula :

rt o n wherein k_x is a constant , k₂ is a constant and M is the torque . It is evident from the equation that there is a load- independent term n₀ and a load-dependent term η> for the rotational speed M . In general , the rotational speed n of the fan motor decreases as the torque M increases .

Furthermore , it is known that the torque M of the rotor 14 is related to the rotor current I_a as follows .

= c *

It is evident from this that a weaker magnetic flux Φ results in a higher rotor current I_a. A higher rotor current I_a results in a lower efficiency of the fan motor 10 since the rotor current I_a is generally greater than the stator current I_s by orders of magnitude . The electrical power loss Pdiss is quadratically dependent on the corresponding current . Therefore , for reasons of efficiency it is important to keep the rotor current I_a as small as possible .

Figure 4 shows a diagram with two different fan impeller curves A, B for two fan impellers 24 and a plurality of motor curves of a fan motor 10 for different magnetic fluxes Φ. The rotational speed n versus the torque M is plotted in the diagram. The corresponding combinations of fan impeller 24 and fan motor 10 may be used in an HVAC module 22.

The various magnetic fluxes Φ that act between the stator 12 and the rotor 14 of the fan motor 10 are a magnetic flux Φ₀, having a flux strength Φ_Ν/ and further magnetic fluxes to Φ to Φ₄ normalized thereto, the respective flux strength of which is 90% , 80% , 70% and 50% of the strength Φ_Ν.

The different flux strengths or flux densities occur if the thermistor 20 changes its resistance value on account of a temperature change, as a result of which the stator current I_s flowing through the stator winding 16 and the magnetic flux generated as a result change . The different magnetic flux Φ_± thus represent the temperature-dependent power regulation 18.

It is clear from the formulae indicated above that the rotational speed n of the rotor 14 rises with lower magnetic flux Φ on account of the load- independent term n₀ (ordinate sections of the magnetic flux Φ_±) , whereas the rotational speed n decreases on account of the load-dependent term n_1; that is to say under load . In this case , in particular the relation of the rotational speed to the magnetic flux Φ may change, as evident from the points of intersection of the magnetic flux Φ± among one another .

It is furthermore evident from the diagram that the first alternative (curve A) is the better combination of fan impeller 24 and fan motor 10 if the HVAC module 22 with this combination is usually operated in a lower or medium power range . This is owing to the fact that said combination has a higher rotational speed n with decreasing magnetic flux Φ, which corresponds to a higher power or speed of the fan motor 10. However, a lower magnetic flux Φ results in a higher rotor current I_a, which correspondingly reduces the efficiency.

By contrast , the combination in accordance with the second alternative (curve B) has a lower rotational speed n in the case of a weak magnetic flux Φ which corresponds to a low speed of the fan motor 10. Therefore , this combination is suitable for an HVAC module 22 which is usually operated in an upper power range, that is to say at high rotational speed, in order not to impair the efficiency of the fan motor 10.

The choice of the thermistor 20 , in particular whether the thermistor 20 is embodied as a PTC or NTC thermistor, furthermore makes it possible to set whether the magnetic flux Φ decreases or increases with rising temperature of the medium. As a result , it is likewise possible to influence whether the rotational speed n of the fan motor 10 decreases or increases with rising temperature . In particular, what is of importance here is to what temperature of what medium the power regulation 18 regulates the power of the fan motor 10 and of the HVAC module 22. Figure 5 shows a diagram with a further fan impeller curve C and motor curves of a fan motor 10 for various magnetic fluxes Φ± . The magnetic fluxes Φ_± exhibit a magnetic flux Φ, having a specific flux strength, and further magnetic fluxes Φ_λ to Φ₇ normalized thereto, the flux strength of which is respectively 90% , 80% , 70%, 60%, 50%, 40% and 30% of the specific flux strength .

In the case of a relatively high magnetic flux ( Φ_0: the fan motor 10 has the lowest no-load rotational speed and the lowest dependence of the rotational speed n on the torque M, whereas the no-load rotational speed rises with a weakening magnetic field or decreasing magnetic flux Φ. Furthermore , the rotational speed n and the torque M of the combination of fan motor 10 and fan impeller 24 rise for a weakening magnetic flux Φ. The motor curves can be derived in particular from the equation regarding the rotational speed n . Figure 6 shows a diagram showing the energy consumption versus the resistance value R of the power regulation for a fan motor 10 according to the invention (curve D) and a fan motor from the prior art (curve E) . The resistance value R is inversely and linearly proportional to the speed of the fan motor, such that a lower resistance value R means a high speed of the corresponding fan motor . The resistance values R or the speed of the fan motor may be subdivided into three power ranges LI to L3 , a lower power range LI, a medium power range L2 and an upper power range L3.

The comparison of the two curves D and E illustrates that the fan motor 10 according to the invention has a significantly lower energy consumption compared with the fan motor known from the prior art , which is embodied as a brush motor and comprises a stator with permanent magnets .

The lower energy consumptions in the lower and medium power ranges LI and L2 are attributable to the fact that significantly lower energy losses occur at the resistors in the fan motor 10 according to the invention . In the prior art , resistors are connected to the rotor in order to control the power of the fan motor by means of a variation of the electromagnetic rotor field . The rotor current is significantly higher than the stator current , for which reason correspondingly high energy losses occur at the resistors . This becomes apparent in the lower and medium power ranges LI and L2 since more resistors are connected there .

According to the invention, by contrast , the stator field is varied on the basis of the automatic power regulation 18 comprising the variable resistor 20 in order to regulate the power of the fan motor 10. In this case , the significantly lower current of the stator 12 flows through the variable resistor 20 , for which reason correspondingly lower energy losses occur at the resistor 20 if the variable resistor 20 has a high resistance value .

In the upper power range L3 , however the fan motor from the prior art has advantages with regard to the energy- consumption, since no resistor at which power is lost has to be connected in this range . Furthermore , an additional excitation of the stator field, as is provided according to the invention need not be implemented .

However, the upper power range L3 is rarely used as viewed over the year, as is clear from Figure 7 , which illustrates the statistical distribution of the used speeds of a fan motor over a year . As already mentioned, there is a proportional relationship between the speed of the fan motor and the resistance value R of the power regulation 18.

The region illustrated in a dashed manner in the diagram in Figure 7 may be covered in particular by the power regulation 18. It comprises the power ranges L2 and L3 , that is to say in particular the power range L2 which is used the most ( see Figure 7 ) and in which much energy may be saved (see Figure 6) . As a result , the efficiency of the fan motor 10 according to the invention is correspondingly high as viewed over the whole year . The invention thus provides a fan motor 10 and a HVAC module 22 which, as viewed over the whole year , are constructed in an efficiency-optimized and also simple and cost-effective manner . Furthermore , they can regulate their power themselves , with the result that a separate power regulation may be dispensed with .

Claims

Patent Claims

1. DC fan motor ( 10 ) for a heating, ventilation and/or air-conditioning system module ( 22 ) of a motor vehicle, comprising a rotor (14 ) and a stator (12) having at least one stator winding ( 16 ) which in the energized state generates an electromagnetic stator field which interacts with the rotor ( 14 ) in order to cause the latter to perform a rotational motion, wherein provision is made of a preferably continuously variable power regulation (18) comprising at least one resistor (20) having a variable resistance value , wherein the power regulation ( 18 ) is electrically coupled to the at least one stator winding (16) in order to vary the current flow through the stator winding ( 16 ) .

2. DC fan motor ( 10 ) according to Claim 1 , characterized in that a change in the resistance value varies the current intensity of the current flowing through the at least one stator winding ( 16 ) and hence the strength of the electromagnetic stator field.

3. DC fan motor ( 10 ) according to Claim 1 or 2 , characterized in that the power regulation ( 18 ) exclusively consists of the at least one resistor (20) .

4. DC fan motor ( 10 ) according to any of the preceding claims , characterized in that the resistor (20) is a thermistor, the resistance value of which changes depending on its temperature .

5. DC fan motor ( 10 ) according to Claim 4 , characterized in that the thermistor (20) is arranged in a region around which a medium flows , or at a section through which a medium flows , such that the DC fan motor (10) itself regulates its power depending on the temperature of the medium .

6. DC fan motor ( 10 ) according to Claim 4 or 5, characterized in that the thermistor (20) is a PTC or NTC thermistor .

7. DC fan motor ( 10 ) according to Claim 1, characterized in that the resistor (20) is a manually adjustable potentiometer .

8. DC fan motor ( 10 ) according to any of the preceding claims , characterized in that the rotor (14) has at least one pole with an electrical rotor winding which, upon current flowing through, generates an electromagnetic rotor field which interacts with the electromagnetic stator field .

9. DC fan motor ( 10 ) according to any of the preceding claims , characterized in that the stator (12) and the rotor ( 14 ) are electrically connected in parallel , such that the DC fan motor (10) is a shunt - wound motor .

10. Heating , ventilation and/or air-conditioning system module (22 ) for a motor vehicle, comprising at least one fan impeller ( 24 ) and a DC fan motor ( 10 ) according to any of the preceding claims which drives the fan impeller (24 ) .

11. Heating, ventilation and/or air-conditioning system module ( 22 ) according to Claim 10 , characterized in that the at least one resistor (20) is a thermistor arranged in the heating, ventilation and/or air- conditioning system module ( 22 ) .

12. Heating , venti lation and/or air-conditioning system module (22 ) according to Claim 10 or 11 , characterized in that the resistor (20) is arranged in a region around which a medium flows or at a section through which a medium flows in the heating, ventilation and/or air-conditioning system module ( 22 ) , in particular wherein the medium is a refrigerant flowing through an air-conditioning circuit .

13. Heating , ventilation and/or air-conditioning system module (22 ) according to Claim 11 or 12 , characterized in that the heating, ventilation and/or air-conditioning system module (22 ) itself regulates its power depending on the temperature of the medium, in particular the flow rate drawn in by the fan impeller (24 ) .

14. Heating, ventilation and/or air-conditioning system module (22 ) according to any of Claims 11 to 13 , characterized in that the thermistor (20) is arranged in or at a heat exchanger (26 ) of the heating , ventilation and/or air-conditioning system module ( 22 ) , around which or through which heat exchanger flows an air flow directed in the vehicle interior .