Expansion valve

Abstract

The invention relates to an expansion valve (1) comprising a housing (4), a sensor (29), a stepper motor (6) or a BLDC motor, a valve seat (7) and a valve body (8) interacting with the valve seat, wherein the stepper motor (6) or the BLDC motor comprises a rotor (10) and a stator surrounding the rotor (10), wherein the rotor (10) comprises a shaft (13) and a permanent magnet (14) fixed on the shaft for co-rotation, wherein the sensor (29) is designed to detect the axial position and / or the rotation angle of the permanent magnet (14). In this way, an expansion valve (1) with optimized installation space requirements and low cost can be obtained.

Description

Technical Field

[0001] The invention relates to an expansion valve for an air conditioning system of a motor vehicle. The invention also relates to a permanent magnet for such an expansion valve and to a motor vehicle air conditioning system comprising an expansion valve of this type. Background Art

[0002] An expansion valve, also called a throttle valve, is a valve that reduces the pressure of the fluid flowing through it by locally narrowing the flow cross section and thereby achieves a volume increase or expansion, respectively. In air conditioning systems, especially in motor vehicles, such an expansion valve reduces the pressure of the refrigerant, which usually enters the expansion valve when it is an almost boiling liquid. It therefore undergoes an isenthalpic change of state, since the refrigerant releases pressure when passing through the expansion valve (the pressure drops from 10 bar to 1 bar, for example, and the temperature of the liquid drops at the same time). The purpose of the expansion in the valve is that the liquid reaches the evaporator with a lower superheat (still in liquid form). The refrigerant then reaches the evaporator, where the evaporation process of the liquid part of the refrigerant absorbs heat from the surrounding area and thus evaporates. The fluid or air flowing through the evaporator (heat exchanger) is thereby cooled, respectively.

[0003] However, in the case of the electric expansion valves known from the prior art, it is disadvantageous that, in order to detect the valve position, they usually have separate permanent magnets arranged on the rotor of the expansion valve, which permanent magnets require not only additional assembly work but also a need for additional installation space. Summary of the invention

[0004] The invention therefore solves the problem of specifying a development or at least one alternative embodiment for an electric expansion valve, which is characterized in particular by means of a compact design.

[0005] The invention is based on the overall concept of integrating a permanent magnet that determines the position of the valve body into a permanent magnet that influences the rotation of the valve body, thereby achieving a lower overall material usage, in particular also reducing the installation space requirements currently required for the position magnet. The expansion valve according to the invention can be used, for example, for an air conditioning system and / or a heat exchanger (cooler) for battery cooling or oil cooling of a motor vehicle, which has a housing, a sensor, a stepper motor or a BLDC motor, a valve seat, and a valve body that interacts with the valve seat. The valve body is preferably formed as a so-called valve needle and can be preloaded into a closed position close to the valve seat by means of a spring, wherein this type of spring can be used in particular for tolerance compensation. The stepper motor or BLDC motor has a rotor and a stator around the rotor, for example at least two electrical coils arranged around the rotor and spaced apart from each other in the axial direction of the rotor. Thus, the adjustment of the valve body and the resulting opening or closing of the expansion valve respectively occur by means of the rotation of the rotor, whereupon the latter is adjusted axially together with the valve body. The rotor has a shaft and a permanent magnet connected to the shaft in a rotationally fixed manner. In response to the rotation of the shaft, the shaft is axially adjusted together with the valve body in the direction of the valve seat or away from the valve seat. The axial position and / or the rotation angle of the permanent magnet are detected by a sensor, and the open position or the closed position of the expansion valve is monitored respectively. With the concept according to the present invention, according to this concept, the permanent magnet required for the rotation of the shaft and the permanent magnet required for detecting the position of the valve body and thus the open state of the expansion valve are integrated in one permanent magnet, so that a particularly compact permanent magnet can be obtained, which not only reduces the installation space required for the expansion valve, but also reduces the material used for the production of the permanent magnet. As a result, the expansion valve according to the present invention can be produced in a cost-effective, resource-saving and installation space-optimized manner.

[0006] In an advantageous further development of the invention, the permanent magnet is formed in a pot-shaped manner and has a signal generator region and a rotor region. The signal generator region is thus preferably facing the sensor, while the rotor region surrounds the shaft. Since the rotor regions of the permanent magnet are arranged spaced apart in an annular manner around the shaft, a part of the shaft can be arranged in the rotor region of the permanent magnet and can thus be accommodated in a space-saving manner.

[0007] The shaft advantageously has a first longitudinal end region and a second longitudinal end region and is arranged in a rotationally fixed manner, wherein the first longitudinal end region of the shaft is in the region of the signal transmitter of the permanent magnet and the shaft has a blind hole-like recess for accommodating the valve body in its second longitudinal end region. This also enables a particularly space-optimized embodiment.

[0008] The shaft and the valve body are advantageously at least partially arranged in the valve body guide, wherein the shaft has an external thread and the valve body guide has a corresponding internal thread, or vice versa, so that in response to the rotation of the shaft, the shaft is axially adjusted together with the permanent magnet, and the valve body is thereby pushed onto the valve seat or lifted from the valve seat. In this case, the sensor can thereby detect the axial adjustment and / or rotation of the permanent magnet, because in response to the rotation of the shaft, the permanent magnet is axially adjusted together with the shaft. Of course, alternatively, it can also be provided that the shaft has an external thread and the valve body guide has a corresponding internal thread, or vice versa, wherein in response to the rotation of the shaft, the shaft is axially adjusted independently of the permanent magnet, and the valve body is thereby pushed onto the valve seat or lifted from the valve seat. In this case, the sensor can therefore only detect the rotation of the permanent magnet, because in response to the rotation of the shaft, only the shaft is axially adjusted in this case, while the permanent magnet is not axially adjusted, the permanent magnet axially remaining in its position and therefore at the same distance from the sensor.

[0009] The external thread on the shaft and the corresponding internal thread can generally be considered similar to a threaded spindle, in which case a rotational motion is converted into a translational motion. The threaded spindle consists of a screw, which in simple applications is a cylindrical round rod to which a trapezoidal, pointed or flat thread is attached. For cost reasons, a pointed thread with a metric size of M5 x 0.25 is therefore particularly advantageous.

[0010] In the case of an advantageous further development of the solution according to the invention, a separator tank is provided which surrounds the rotor and separates the wet area on the rotor side from the dry area on the stator side. The expansion valve according to the invention can thus be formed as a so-called wet running meter, in which case the rotor is arranged in the refrigerant. However, by means of the separator tank, the relatively sensitive coils and the electronics of the control board can be reliably kept dry, which are thus arranged in a protected manner, and the expansion valve according to the invention can thus remain functional for a long time.

[0011] In the region of its signal generator, the permanent magnet advantageously has at least one magnetic pole pair. This type of magnetic pole pair consists of a north pole and a south pole, which respectively provide relatively simple distance or range measurements, and / or can directly convert changes in the rotation angle into the opening of the expansion valve for corresponding sensors, such as 3D Hall sensors. Non-contact and non-touch distance detection can be performed by this type of 3D Hall sensor, which in particular provides a greater advantage that the 3D Hall sensor can be set in a dry area of ​​the expansion valve, while the rotor or the permanent magnet can be set in a wet area respectively. With this type of sensor, all spatial directions can be detected with the aid of a single sensor, which not only provides cost advantages, but also provides advantages in installation space. This type of Hall sensor also provides a greater advantage in that even if the magnetic field in which the corresponding Hall sensor is located is constant, this type of Hall sensor still provides a signal. Accordingly, it is relatively easy to detect the rotation angle of the rotor or the position or distance of the rotor to the Hall sensor, respectively, and therefore also detect the opening state of the expansion valve.

[0012] In the case of a further advantageous embodiment of the solution according to the invention, the shaft passes through the signal generator region of the permanent magnet. This provides a great advantage in the case of assembling the expansion valve according to the invention, in which case the spring is initially (optionally) inserted into the blind hole-shaped recess at the second longitudinal end region of the shaft, and subsequently the valve body is inserted, and a ring element which limits the maximum extension position of the valve body from the blind hole-shaped recess can also be pressed into the blind hole-shaped recess. In order to press in a ring element of this type, the shaft must be pushed against the base, which can be done relatively easily in the case of the shaft passing through the permanent magnet, because in this case the shaft is not supported on the permanent magnet, but directly on the corresponding base. A rotor with significant assembly advantages can thus be obtained.

[0013] In the case of a further advantageous embodiment of the solution according to the invention, the shaft is connected to the signal generator region of the permanent magnet in a form-fitting and / or material-fitting manner at its first longitudinal end region. It is conceivable, for example, that the shaft has a corresponding recess or knurling or collar, respectively, wherein the signal generator region of the corresponding permanent magnet has a negative profile formed to be complementary thereto. This enables a form-fitting connection between the permanent magnet and the shaft, which can be additionally supported, for example, by using an adhesive. A relatively simple form-fitting, torque-transmitting connection between the shaft and the signal generator region of the permanent magnet can be achieved, for example, by means of a non-circular collar at the shaft.

[0014] The invention is also based on the following general idea, namely to provide a permanent magnet for an expansion valve as described in the preceding paragraph, which is formed in a pot-like manner and has a signal generator area, which forms the base of the pot, and a rotor area, which forms the wall of the pot, and the permanent magnet has a plurality of magnetic poles in its rotor area, which extend in the axial direction and are also arranged alternately in the circumferential direction. A permanent magnet of this type can thus be manufactured as a prefabricated component or can be distributed in two parts, wherein the two parts can be relatively easily attached to the corresponding shaft in a form-fitting manner and can be connected to the shaft in a form-fitting manner. In the case of this variant of the permanent magnet comprising two half shells or in the case of a fully manufactured, i.e. one-piece variant, an adhesive can be additionally used to fix the shaft in a rotationally fixed manner in the signal generator area of ​​the permanent magnet. By means of a permanent magnet of this type according to the invention, a magnet with a particularly compact construction can be produced, which magnet, due to its rotor area, can also accommodate a large part of the shaft and at least a part of the needle valve body, as well as the valve body guide, and can thus be arranged in a particularly space-optimized manner.

[0015] The invention is also based on the general idea of ​​providing an air conditioning system for a motor vehicle, comprising a compressor, an evaporator, a condenser and an expansion valve as described in the preceding paragraph, so that the advantages of the expansion valve as described in the preceding paragraph can be transferred to the air conditioning system.

[0016] The invention is also based on the general idea of ​​using such an expansion valve in an oil cooler or cooling system for a battery by means of a heat exchanger (cooler refrigerant-cooling water circuit) and a condenser in combination with a vehicle air conditioning system or also in a separate cooling circuit.

[0017] It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination but also in other combinations or alone without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Preferred exemplary embodiments of the invention are shown in the drawings and will be described in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0019] Schematically respectively:

[0020] Figure 1 shows a cross-sectional view of an expansion valve according to the present invention,

[0021] Figure 2 shows a detailed cross-sectional view of a permanent magnet according to the present invention,

[0022] Figure 3An air conditioning system comprising an expansion valve according to the invention is shown. DETAILED DESCRIPTION

[0023] according to Figure 1 , according to the present invention for motor vehicles 3 (see Figure 3 ) has a housing 4, a sensor 29, a control board 5, a stepper motor 6 or a BLDC motor, a valve seat 7, a valve body 8 interacting with the valve seat, and a valve body guide 9 firmly connected to the housing 4. The stepper motor 6 or BLDC motor has a rotor 10 and, in the present example, at least two coils 11 surrounding the rotor 10 and forming a stator. Therefore, when viewed in the axial direction 12, the coils 11 are thus respectively offset from each other or spaced apart from each other. The rotor 10 then has a shaft 13 and a permanent magnet 14, which is fixed in rotation (see in particular Figure 2 ) is connected to the shaft and is preferably formed in a pot-like manner, the permanent magnet 14 can have a signal generator region 15 and a rotor region 16. The signal generator region 15 thus faces the control board 5 or the sensor 29, respectively, while the rotor region 16 surrounds a large part of the shaft 13. According to the invention, the sensor 29 is formed to detect the axial position and / or the rotation angle of the permanent magnet 14. In the example shown, the shaft 13 is also in the region of the signal generator region 15, which is surrounded by the permanent magnet 14. The shaft 13 has a first longitudinal end region 17 and a second longitudinal end region 18 (see again Figure 2 ), and is firmly integrated, in particular in a rotationally fixed manner, wherein its first longitudinal end region 17 is integrated in the signal generator region 15 of the permanent magnet 14, and the shaft 13 also has a blind hole-like recess 19 for accommodating the valve body 8 and a spring 20 at its second longitudinal end region 18, which preloads the valve body in the direction against the valve seat 7.

[0024] Therefore, as can be seen from the figure, especially from Figure 1 As a result, the shaft 13 and the valve body 8 are at least partially arranged in a valve body guide 9 which in turn is firmly connected to the housing 4 , in particular for example by means of pressing or bonding.

[0025] In order to adjust the valve body 8 in the axial direction 12 and thus open or close the expansion valve 1 according to the invention, respectively, the rotor 10 is rotated, wherein the axial adjustment can preferably be achieved by means of a thread provided between the shaft 13 and the valve body guide 9. For this purpose, the shaft 13 has an external thread 21, and the valve body guide 9 has a corresponding internal thread 22 that interacts with the external thread 21, so that in response to the rotation of the shaft 13, the shaft together with the permanent magnet 14 is axially adjusted, and the valve body 8 is thereby pushed onto the valve seat 7 or lifted from the valve seat. The rotation of the rotor 10 is achieved by providing the stator or the coil 11, respectively, with a corresponding corresponding current. If the rotor 10 is thus rotated, it is, for example, moved in the direction according to Figure 1 The axial direction 12 of the rotor 10 is adjusted downward, and the spring 20 arranged in the blind hole-shaped recess 19 is pushed and thereby tensioned, and the valve body 8 is pre-tensioned against the valve seat 7 on the housing side. If the rotor 10 is rotated in the opposite direction by providing a corresponding current to the coil 11, the rotor is adjusted upward in the axial direction 12, so that the spring 20 relaxes, and the contact pressure of the valve body 8 on the valve seat 7 begins to decrease until the valve body 8 abuts against the ring element 23 pressed into the blind hole-shaped recess 19 through its collar 24. In this state, the valve body 8 reaches the maximum extension state outside the blind hole-shaped recess 19, so that in response to the further upward adjustment of the rotor 10, the valve body 8 is lifted from the valve seat 7.

[0026] In response to the rotation of the shaft 13 , the shaft can be axially adjusted together with the permanent magnet 14 or separately therefrom, and the valve body 8 can thereby be pushed onto the valve seat 7 or can be lifted from the valve seat.

[0027] The ring element 23 can thus be pressed into the blind hole-like recess 19, wherein the ring element 23 always maintains a radial distance from the valve body 8, so that the valve body is arranged in a non-contacting manner on the ring element 23. The shaft 13 is usually mounted in a sliding manner in the upper region of the valve body guide 9, that is, in the region above the spring 20.

[0028] When further reference Figure 1 , it can be seen that a separation tank 25 is provided around the rotor 10, which separates the rotor-side wet area 26 from the coil-side / stator-side dry area 27. The control board 5 and the stator or coil 11 are therefore respectively arranged in the dry area 27 and are therefore protected.

[0029] When looking at the permanent magnet 14 according to the invention in more detail (see in particular Figure 2 ), it can be seen that the permanent magnet has a plurality of magnetic poles 28 (north-south) in its rotor region 16, which are radially spaced from the shaft 13 and extend in the axial direction 12, and are also arranged alternately in the circumferential direction. The permanent magnet 14 has at least one magnetic pole pair in its signal generator region 15, according to Figure 2, the at least one magnetic pole pair is composed of a semicircular north pole and a semicircular south pole. A sensor 29, in particular a 3D Hall sensor (see Figure 1 ), which faces the shaft 13 and can detect the distance between the first longitudinal end 30 of the shaft 13 and the 3D Hall sensor and the resulting opening state of the expansion valve 1.

[0030] Therefore, if we can Figure 1 and Figure 2 The shaft 13 of the rotor 10 passes through the signal generator region 15 of the permanent magnet 14, which further provides a great advantage that in response to the ring element 23 being pressed into the blind hole-like recess 19 at the second longitudinal end region 18 of the shaft 13, after the spring 20 and the valve body 8 are inserted, there is no support by the permanent magnet 14, but only by the shaft 13 itself, because according to Figure 1 and Figure 2 , the longitudinal end 30 of the shaft extends beyond the signal generator region 15 of the permanent magnet 14 .

[0031] The connection between the permanent magnet 14 and the shaft 13 is thus made by a form-fitting connection and / or a material-fitting connection, so that it is conceivable that the shaft 13 is connected to the signal generator region 15 of the permanent magnet 14 in a form-fitting manner and / or a material-fitting manner at its first longitudinal end region 17. It is conceivable that the form-fitting connection also allows torque transmission, for example, by means of a non-circular form-fitting connection body 31 and a negative contour 32 in the permanent magnet 14 that is formed to be complementary to the non-circular form-fitting connection body. By means of this type of form-fitting connection, torque transmission can be made between the permanent magnet 14 and the shaft 13, wherein axial adjustment between them can be allowed. It goes without saying that the rotationally fixed connection between the permanent magnet 14 and the shaft 13 can also be supported by means of an adhesive and the material fit therefrom. In this case, an axial relative adjustment between the permanent magnet 14 and the shaft 13 is prohibited. In particular, in this case, the permanent magnet 14 is fastened to the shaft 13 so that the permanent magnet and the shaft 13 are coupled in the axial movement direction. It is thus conceivable, for example, that the signal generator region 15 consists of two semicircular poles (North-South) which are attached in radial direction to the form-fitting body 31 of the shaft 13 and are subsequently firmly connected thereto.

[0032] It is also conceivable to extrusion coat the shaft 13 directly with plastic, in particular thermoplastic (eg PA 6), to which magnetizable particles (iron, neodymium, etc.) are added and thereby produce the permanent magnet 14. In contrast to the sintering alternative, this offers the advantages of high strength and bonding to the shaft 13.

[0033] Since the signal generator area 15 and the rotor area 16 are integrated in the one-piece permanent magnet 14, functional integration can be achieved, so that the rotor area 16 required for rotating the rotor 10 and thus opening or closing the expansion valve 1 respectively and the signal generator area 15 required for detecting the open state or closed state of the expansion valve 1 respectively can be integrated in a single common permanent magnet 14, thereby giving the permanent magnet a more compact structure.

[0034] In general, it is also conceivable that the signal generator region 15 and / or the permanent magnet 14 are at a constant distance from the sensor 29. In this case, the expansion valve 1 is adjusted only by means of a rotation of the permanent magnet 14. The shaft 13 can thus be supported in the permanent magnet 14 in an axially movable manner.

[0035] like Figure 3 As shown, the expansion valve 1 according to the invention can be used together with the permanent magnet 14 according to the invention in an air conditioning system 2 of a motor vehicle 3 , for example, wherein this type of air conditioning system 2 also includes a compressor 33 , an evaporator 34 , and a condenser 35 .

[0036] Thus, a cost-effective, functionally integrated and installation-space-optimized expansion valve 1 can be obtained with the expansion valve 1 according to the invention.

Claims

1. An expansion valve (1) for an air conditioning system (2), a battery cooler and / or an oil cooler of a motor vehicle (3), - comprising a housing (4), a sensor (29), a stepper motor (6) or a BLDC motor, a valve seat (7), and a valve body (8) interacting with the valve seat, -in, The stepper motor (6) or the BLDC motor has a rotor (10) and a stator surrounding the rotor (10). wherein the rotor (10) has a shaft (13) and permanent magnets (14) connected to the shaft in a rotationally fixed manner, - wherein the sensor (29) is formed to detect the axial position and / or the rotation angle of the permanent magnet (14), The permanent magnet (14) is formed in a pot-shaped manner and is formed in one piece, and has a signal generator area (15) and a rotor area (16) integrated in the permanent magnet (14), wherein the signal generator area forms the base of the pot and the rotor area forms the wall of the pot.

2. The expansion valve according to claim 1, characterized in that: The signal generator region (15) faces the sensor (29), and the rotor region (16) surrounds the shaft (13).

3. The expansion valve according to claim 1 or 2, characterized in that: The shaft (13) has a first longitudinal end region (17) and a second longitudinal end region (18) and is arranged in a rotationally fixed manner, wherein the first longitudinal end region (17) of the shaft is in the signal generator region (15) of the permanent magnet (14) and the shaft has a blind hole-like recess (19) in its second longitudinal end region (18) for accommodating the valve body (8).

4. The expansion valve according to claim 1 or 2, characterized in that: - the shaft (13) and the valve body (8) are at least partially arranged in a valve body guide (9), - The shaft (13) has an external thread (21) and the valve body guide (9) has a corresponding internal thread (22), or vice versa, so that in response to the rotation of the shaft (13), the shaft together with the permanent magnet (14) is axially adjusted and the valve body (8) is thereby pushed onto the valve seat (7) or lifted from the valve seat.

5. The expansion valve according to claim 3, characterized in that: The shaft (13) is connected at its first longitudinal end region (17) to the signal generator region (15) of the permanent magnet (14) in a form-fitting and / or material-fitting manner, or The shaft (13) is connected to the rotor region (16) of the permanent magnet (14) in a form-fitting and / or material-fitting manner.

6. The expansion valve according to claim 4, characterized in that The shaft (13) has an external thread (21) and the valve body guide (9) has a corresponding internal thread (22), or vice versa, so that in response to the rotation of the shaft (13), the shaft is axially adjusted independently of the permanent magnet (14), and the valve body (8) is thereby pushed onto the valve seat (7) or lifted from the valve seat.

7. The expansion valve according to claim 1 or 2, characterized in that: The signal generator region (15) and / or the permanent magnet (14) are located at a constant distance from the sensor (29).

8. The expansion valve according to claim 1 or 2, characterized in that: The shaft (13) is supported in the permanent magnet (14) in an axially movable manner.

9. The expansion valve according to claim 1 or 2, characterized in that: The permanent magnet (14) is fastened to the shaft (13) such that the permanent magnet is coupled with the shaft in an axial movement direction.

10. The expansion valve according to claim 1 or 2, characterized in that: - the sensor (29) is arranged at the control panel (5), and / or A separator tank (25) is arranged around the rotor (10), which separates the wet area (26) on the rotor side from the dry area (27) on the stator side.

11. The expansion valve according to claim 1 or 2, characterized in that: The permanent magnet (14) has a plurality of magnetic poles (28) in its rotor region (16), the magnetic poles being radially spaced from the shaft (13) and extending in the axial direction (12), and the magnetic poles being arranged alternately in the circumferential direction.

12. The expansion valve according to claim 1 or 2, characterized in that: The permanent magnet (14) has at least one magnetic pole pair in its signal generator region (15).

13. The expansion valve according to claim 1 or 2, characterized in that: The shaft (13) passes through the signal generator region (15) of the permanent magnet (14).

14. The expansion valve according to claim 7, characterized in that The shaft (13) is supported in the permanent magnet (14) in an axially movable manner.

15. A permanent magnet (14) for an expansion valve (1) according to any one of claims 1-11, 13-14, wherein the permanent magnet is formed in a can-shaped manner and has a signal generator area (15) and a rotor area (16), and the permanent magnet has a plurality of magnetic poles (28) extending in the axial direction (12) in its rotor area (16), and the magnetic poles are also arranged to alternate in the circumferential direction.

16. The permanent magnet according to claim 15, characterized in that The permanent magnet (14) has at least one magnetic pole pair in its signal generator region (15).

17. An air conditioning system (2) for a motor vehicle (3), comprising a compressor (33), an evaporator (34), a condenser (35) and an expansion valve (1) according to any one of claims 1 to 14.

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