EXPANSION VALVE

Abstract

An expansion valve for an air conditioning system of a motor vehicle may include a housing, a sensor, a stepping motor or a BLDC motor, a valve seat, and a valve body. The stepping motor or the BLDC motor may include a rotor and a stator surrounding the rotor. The rotor may include a permanent magnet body connected non-rotatably therewith. A separating can may be provided that surrounds the rotor and separates a wet region on a rotor side from a dry region on a stator side. The sensor may be connected with the separating can via an adhesive layer formed as a heat-conductive layer.

Claims

1. An expansion valve for an air conditioning system of a motor vehicle, the expansion valve comprising: a housing; a sensor; a stepping motor or a BLDC motor; a valve seat; and a valve body interacting therewith; wherein the stepping motor or the BLDC motor has a rotor and a stator surrounding the rotor; wherein the rotor has a permanent magnet body connected non-rotatably therewith; wherein a separating can is provided, which surrounds the rotor and separates a wet region on a rotor side from a dry region on a stator side; and wherein the sensor is connected with the separating can via an adhesive layer formed as a heat-conductive layer.

2. The expansion valve according to claim 1, wherein the sensor is configured to detect a magnetic field generated by the permanent magnet body (12.

3. The expansion valve according to claim 1, wherein the sensor is configured to detect a temperature of the sensor and/or of the permanent magnet body.

4. The expansion valve according to claim 1, wherein the sensor is configured to detect an axial position and/or of a rotation angle of the permanent magnet body.

5. The expansion valve according to claim 1, wherein the permanent magnet body is formed in a pot-shaped manner and has a signal generator region and a rotor region.

6. The expansion valve according to claim 5, wherein the signal generator region faces the sensor.

7. The expansion valve according to claim 3, wherein a storage device is provided for recording the temperature measured by the sensor.

8. The expansion valve according to claim 1, wherein the adhesive layer includes an elastomer or a foam that is capable of conducting heat.

9. An air conditioning system of a motor vehicle, comprising: an expansion valve according to claim 1.

10. The expansion valve according to claim 2, wherein the sensor is configured to detect an intensity of the magnetic field.

11. The expansion valve according to claim 2, wherein the sensor is configured to detect a direction vector of the magnetic field.

12. The expansion valve according to claim 1, wherein the sensor is configured to detect a temperature of the permanent magnet body.

13. The expansion valve according to claim 1, wherein the sensor is configured to detect a rotation angle of the permanent magnet body.

14. The expansion valve according to claim 12, wherein a storage device is provided for recording the temperature measured by the sensor.

15. The expansion valve according to claim 1, wherein the adhesive layer includes a foam that is capable of conducting heat.

16. An expansion valve, comprising: a sensor; a motor including a rotor and a stator disposed about the rotor, the rotor has a permanent magnet body; and a separating can disposed about the rotor, the sensor connected to the separating can.

17. The expansion valve according to claim 16, wherein the sensor is connected to the separating can via an adhesive layer.

18. The expansion valve according to claim 17, wherein the adhesive layer is formed as a heat-conductive layer.

19. The expansion valve according to claim 16, wherein the sensor is configured to detect (i) a magnetic field generated by the permanent magnet body, (ii) an axial position of the permanent magnet body, and (iii) a temperature of the magnet body.

20. The expansion valve according to claim 19, including a storage device configured to record the temperature measured by the sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Preferred example embodiments of the invention are illustrated in the drawings and are explained more closely in the following description, wherein the same reference numbers refer to identical or similar or functionally identical components.

[0019] There are shown, respectively schematically,

[0020] FIG. 1 a sectional view through an expansion valve according to the invention,

[0021] FIG. 2 a detail illustration from FIG. 1 in the region of a sensor connected with a separating can via a heat-conductive layer.

DETAILED DESCRIPTION

[0022] According to FIG. 1, an expansion valve 1 according to the invention for an air conditioning unit 2, a battery cooler and/or an oil cooler of a motor vehicle 3 has a housing 4 in which a sensor 5, for example a 3D Hall sensor, and a stepping motor 6 or respectively a BLDC motor, is arranged. A valve seat 7 and a valve body 8 interacting therewith are also provided. The stepping motor 6 or respectively the BLDC motor has a rotor 9 and a stator 10 surrounding the rotor 9, which stator has two coils 11 for example in the case shown in FIG. 1. The rotor 9 has a permanent magnet body 12, wherein the sensor 5 is arranged on a control board 13.

[0023] Furthermore, a separating can 14 is provided, which surrounds the rotor 9 and separates a wet region 15 on the rotor side from a dry region 16 on the stator side. By means of the separating can 14 it is possible to arrange the sensor 5 in the dry region 16 and thus in a protected manner. According to the invention, the sensor 5 is now connected to the separating can 14 via an adhesive layer 18 formed as a heat-conductive layer 17. Hereby, it is possible to enable a thermal and mechanical connection of the sensor 5 to the separating can 14 and thereby to prevent temperature differences between the sensor 5 and the separating can 14, which could lead to inaccuracies in the detection of an opening state of the expansion valve 1. By means of the adhesive layer 18 in particular the occurrence of an insulating air layer lying between the sensor 5 and the separating can 14 is able to be prevented, which, owing for example to higher temperatures in the wet region 15, can lead to a more intensive temperature-related thermal expansion there and thus to measurement inaccuracies.

[0024] Through the mechanical coupling of the sensor 5 with the separating can 14, at the same time also an absolute distance remains constant between the sensor 5 and the separating can 14 or respectively the permanent magnet 12, whereby relative influences on the distance can be at least greatly reduced, preferably even eliminated. Through the initial teach-in of each expansion valve 1, a tolerance-related distance between the sensor 5 and the separating can 14 is also set to zero. In order to keep temperature-related thermal expansions of the adhesive layer 18 as small as possible, the latter is formed to be comparatively thin and has, for example, only a thickness d<1 mm, nominally 0.7 mm.

[0025] In particular an elastomer, or respectively a foam which is capable of conducting heat, comes into consideration as material for the heat-conductive adhesive layer 18, wherein both materials have not only a good thermal conductivity but in addition can also serve as vibration damper between the sensor 5 on the one hand and the separating can 14 on the other hand.

[0026] The sensor 5 is formed here for the detection of a magnetic field generated by the permanent magnet body 12, in particular of an intensity of the magnetic field and/or of a direction vector thereof. Through the detection of a direction vector of the magnetic field of the permanent magnet body 12, its rotation angle position and via this an opening state of the expansion valve 1 can be detected. The sensor 5 can be formed, furthermore, for the detection of a temperature of the sensor 5 and/or of the permanent magnet body 12 or respectively of the separating can 14. By means of a storage device 19 it is possible to record or respectively store at least the temperature measured by the sensor 5, wherein at the same time of course it is also conceivable that the storage device 19, which is able to be read by a corresponding control apparatus, also records an opening state of the expansion valve 1 or respectively an opening position of the valve body 8. Hereby, a position of the expansion valve with an associated temperature is able to be detected and able to be evaluated. Basically, it is also conceivable here that temperature-related changes to the opening position can be detected and subtracted.

[0027] A so-called “sensor drift”, i.e. a change of magnetic characteristics with a changing temperature can also be better compensated by means of the heat-conductive layer 17 or respectively the adhesive layer 18. The colder the material is, for example, such a sensor drift becomes all the more intensively noticeable. Thereby, a measured field value at different temperatures can represent different location positions of the permanent magnetic body 12 and thus different opening positions. The temperature-related magnetic characteristic values can be corrected by means of software to the nominal temperature, in particular ambient temperature. For this, an additional temperature sensor 24 on the control board 13 is necessary, which can be provided for this on the control board 13. However, so that it can correctly detect the temperature of the permanent magnet body 12, an air gap between sensor 5 or respectively additional temperature sensor 24 and separating can 14 must be “short-circuited” via gap filler, i.e. eliminated as far as possible, which takes place with the heat-conductive layer 17 or respectively the adhesive layer 18.

[0028] The permanent magnetic body 12 is formed here in a pot-shaped manner and has a signal generator region 20 and a rotor region 21, wherein the signal generator region 20 faces the sensor 5 and has a 2-pole magnet (north-south). Thereby, not only can the magnetic field intensity of the signal generator region 20 and thus of the permanent magnet body 12 be measured, but also the vectors of the field alignment, whereby a particularly exact detection of the magnetic field by the sensor 5 and thus of a position of the valve body 8, which is operatively connected with the permanent magnet body 12, is made possible.

[0029] Between the permanent magnet body 12 and the valve body 8, two waved axial springs 22 are arranged, which pretension the valve body 8 against a threaded bush 23, so that the valve body 8 always has a defined position and cannot move loosely within the rotor. With the adhesive layer 18, formed according to the invention as heat-conductive layer 17, for the mechanical and thermal coupling of the sensor 5 with the separating can 14, temperature differences between the sensor 5 and the separating can 14 or respectively the permanent magnet 12 can be at least minimized, preferably even eliminated, whereby interferences, which can lead to errors in the detection of the position of the valve body 8, can be at least greatly reduced. Through the mechanical coupling of the sensor 5 with the separating can 14, it is possible, in addition, to keep a relative distance between these two components the same in a temperature-independent manner, whereby also interferences to the detection of the position of the valve body 8 of the expansion valve 1 can be eliminated. The sensor 5 is arranged here directly on the control board 13 and is not connected therewith by means of flexible connections.