WO2021121897A1

WO2021121897A1 - Valve device

Info

Publication number: WO2021121897A1
Application number: PCT/EP2020/083504
Authority: WO
Inventors: Andres Tönnesmann; Matthias Baden; Jens OESTERDIEKHOFF; Jörg Gissing
Original assignee: Pierburg Gmbh
Priority date: 2019-12-18
Filing date: 2020-11-26
Publication date: 2021-06-24
Also published as: DE102019134949A1

Abstract

Valve devices, in particular for cooling circuits, having an actuator (34) which has an electric motor (35) having a driven rotor (40), a valve body (20) which is drivable by means of the actuator (34) and a position feedback unit (62, 66) on the electric motor (35), via which position feedback unit a position of the rotor (40) can be determined, are known. In order to be able to determine a precise and absolute angular position of the valve body (20) from the measured rotor position, including in the case of the existing translation or reduction, according to the invention the valve device has an additional valve position sensor (74) which generates a signal from a magnetic field that changes as a result of the rotation of the valve body (20) and which can be designed as a simple switch.

Description

B E S C H R E I B U N G Valve device

The invention relates to a valve device with an actuator which has an electric motor with a driven rotor, a valve body that can be driven by means of the actuator, and a position feedback unit on the electric motor, via which a position of the rotor can be determined.

In motor vehicles, both when using internal combustion engines and when using electric drives or hybrid drives, a large number of valve devices are required in order to regulate either a flow of liquid or a flow of gas. It has become customary to use actuators that have an electric drive, in particular using electric motors that are electronically commutated. These actuators mostly drive a transmission, the output shaft of which is coupled to a valve body. A distinction must be made here between gears in which the rotational movement of the electric motor is converted into a lifting movement and which only serve to achieve a high gear ratio or reduction. A high reduction ratio, that is to say a transmission ratio of the input speed to the output speed of well over 1, is particularly desirable for precise regulation.

Such valves can either be flap valves or rotary slide valves, such as those used, for example, in cooling circuits. For precise regulation of a corresponding volume flow, it is necessary to use continuously controllable valves, the rotational position of which can be determined as precisely as possible, see above that the actuators for regulation can be controlled as precisely as possible.

This is achieved either by direct detection of the rotary position of the valve body or by moving the valve against a stop which serves as a reference position from which a position of the valve can be calculated using the data of a position sensor of the actuator. While the necessary installation space is often not available in the first case or the electronics required in this way are not to be arranged in the area of the valve body or expensive sensors should be dispensed with for reasons of cost, the problem in the second case is that when moving into the stop position, these do not exist can always be precisely determined. Particularly in the case of rotary slide valves in which the valve body itself does not have a stop, a reliable determination of the reference position by approaching a stop is completely unnecessary.

Against this background, the task arises of providing a valve device with which the position of the valve body can be determined in the simplest possible way. This should also work if the valve body is a rotary valve body without a stop and a direct measurement of the position of the valve body over the entire adjustment range is not possible.

This object is achieved by a valve device with the features of main claim 1.

The valve device according to the invention thus has an actuator which consists of an electric motor which has a rotor which is driven directly by the stator magnetic field. The actuator has a position feedback unit which measures a position of the rotor or an actuator shaft of the electric motor connected to it or calculated based on a model. This can be done, for example, via sensors whose output voltage is proportional to a magnetic field of the rotor or a permanent magnet acting on them on the actuator shaft or on the rotor and thus represents a measure of the position of the actuator shaft or the rotor, or by using the retroactive electromagnetic force or the magnetic anisotropy. Correspondingly, a rotational position of the rotor can be determined in a known manner from the voltage generated or the measured current or the measured voltage. In addition, the valve device has a valve position sensor which generates a signal from a magnetic field that changes due to the rotation of the valve body. This means that a change in the magnetic field acting on the valve position sensor corresponds directly and directly to the rotation of the valve body or a component permanently connected to it, i.e. the change is generated by the valve body itself or the components permanently connected to it. With a very high reduction ratio, the rotational position of the rotor can only serve to identify several possible positions of the valve body by means of the position sensor. However, in order to be able to determine an absolute rotational position of the valve body, the valve position sensor is used so that two output signals from the two sensors are available, which enable a clear assignment and which can be used to verify the measured values of a sensor or the resolution of the measurements of the valve position sensor with an existing reduction, since the resolution of the first sensor is more accurate with respect to the angular position of the valve body. Correspondingly, two independent signals are generated which, on the one hand, enable precise position detection and, on the other hand, enable the signals to be checked for plausibility so that errors can be detected.

The valve position sensor is preferably a switch which switches at a reference position of the valve body when a transmitter element is passed. Accordingly, this switch only generates at a certain position a signal, which however corresponds to a defined position, which can thus be used as an exact reference position, from which a position of the valve body can be calculated with high accuracy based on the signals of the position sensor or by means of counting and scaling.

The valve position sensor is preferably a Hall switch that interacts with a permanent magnet attached to the valve body, or a Hall switch with a permanent magnet that interacts with a magnetizable element as a transmitter element on the valve body. These Hall switches can be manufactured inexpensively and provide a very precise switching point so that the reference position can be determined with a high degree of accuracy. They react to a change in the magnetic field, which is generated in the first case by the passing magnet itself and in the second case by the magnetizable element through which the magnetic field of the

Permanent magnet, which is attached directly to the sensor, is changed. In a further embodiment, several permanent magnets or several magnetizable elements, through which the valve position sensor switches, are attached to the valve body. These can be simple and inexpensive pin magnets, which generate switching in the sensor when it is passed or by means of a metal ring with axially or radially protruding tooth-shaped transmitter elements. The use of several permanent magnets or tooth-shaped transmitter elements is used to correct the calculated valve positions or to check their correctness. The transmitter elements advantageously have different widths or are arranged distributed over the circumference at a different distance from one another, so that the different reference positions can be assigned to a specific adjustment angle. It is advantageous if the position feedback unit and the valve position sensor are connected to a control unit, the control unit calculating the further rotation from the reference position determined by means of the valve position sensor on the basis of the data determined by the position feedback unit. Correspondingly, the signals of both position feedbacks are processed in the one control unit, so that a calculation can be carried out in this control unit and can subsequently also be used to control the actuator. For this purpose, the power electronics of the actuator or the electric motor are preferably also integrated in the control unit.

The position feedback unit of the electric motor is preferably formed by a position sensor, in particular a magnetoresistive sensor, in which a voltage can be generated by a magnetic field of the electric motor or a transmitter magnet on the rotor or on an actuator shaft, which voltage corresponds to the position of the rotor or the actuator shaft. Such a sensor works without contact and enables the position of the rotor or the actuator shaft to be determined very precisely.

Alternatively, the position feedback unit of the electric motor is formed by the control unit of the electric motor and an ammeter or voltmeter, via which the rotor position can be determined by means of a model-based EMF method or EMF method with zero crossing. This method for determining the rotor position is known in the case of electronically commutated electric motors and enables the rotor position to be determined without having to use position sensors.

In a particularly preferred embodiment of the invention, a gear is formed between the rotor and the valve body, so that a reduction is achieved between the drive and the valve body. This reduction can be 1: 100, for example, when using a Wolfrom gear. The position of the valve body can thus be determined very precisely by means of the position feedback unit for highly precise regulation after the reference position has been established by the valve position sensor, since relatively large adjustment angles on the rotor only lead to small adjustment angles on the valve body.

Furthermore, it is advantageous if the electric motor is electronically commutated and the position sensor detects the position of the permanent magnet rotor and the signal of the

Position sensor is used to commutate the electric motor. This means that no additional magnets or sensors are required. Instead, the position detection of the electric motor can also be used directly for the position detection of the valve body, for which only the

Reference position must be set with the valve position sensor.

This invention can also be used particularly advantageously when the valve body is a rotary slide valve, since a rotary slide valve usually does not have a stop, so that the reference position has to be defined differently, which in the present invention by means of the

Valve position sensor is feasible. There is also no need for larger magnets in the area of the valve body or circuit boards in the area of the

Valve body are arranged.

A valve device is thus created which enables highly precise regulation of a valve body without having to directly detect its position. Instead, especially in connection with a reduction, which can be up to 1: 100, for example, an exact position can be calculated without having to use high-precision sensors, since only relatively large angles have to be detected on the actuator in order to calculate precise small angles on the valve body to be able to. For this purpose, only the reference position is required using the Define valve position sensor, which can, however, be designed in a simple manner as a switch and can thus be manufactured and installed inexpensively. An embodiment of a valve device according to the invention for a coolant circuit is shown in the figures and is described below.

Figure 1 shows a side view of the valve device according to the invention in a sectional view.

FIG. 2 shows a perspective functional view of the valve body with the valve position sensor of the valve device according to the invention in a partially transparent representation.

The valve device according to the invention has a flow housing 10 with an inlet 12 and an outlet 14, which in the present exemplary embodiment are formed in a radially extending inlet connector 16 and an outlet connector 18 that is also radially extending and offset by 90 ° to the inlet connector 16. In the flow housing 10, which is essentially shaped as a hollow cylinder, a rotary slide member serving as a valve body 20 is mounted on an actuator shaft 22, which has a flow opening 24 via which a fluidic connection can be established between the inlet 12 and the outlet 14. In the present embodiment, the throughflow opening 24 is formed merely as a recess extending approximately over half the circumference of the otherwise approximately cylindrical valve body 20.

The actuator shaft 22 is fastened at its one axial end in a receiving opening 26 on a base 28 which closes the flow housing 10 and is fastened at its opposite axial end in a receptacle 29 on a base 30 of a containment shell 32. The valve body 20 is driven via an actuator 34, the electric motor 35 of which is designed as a two-phase claw-pole motor, each phase having four pole pairs. A rotor 40, and with it the actuator shaft 22 on which it is attached, can be driven uniformly and adjusted to any rotational positions by a corresponding commutation, which takes place out of phase for two coils 36 of a stator 38 of the claw pole motor.

The rotor 40 is separated from the stator 38 by the can 32, which is formed in one piece with an actuator housing 42 by a collar 43 extending radially outward from the can 32 to the surrounding actuator housing 42, which axially delimits the stator 38. The actuator housing 42 surrounds the actuator 34 radially and is attached to the flow housing 10, so that in the radial interior of the flow housing 10 between the actuator 34 and the valve body 20, an interior space 44 is created, which passes axially through the can 32 and its collar 43 and radially through the actuator housing 42 and the flow housing 10 is delimited and is delimited on the axially opposite side by the bottom 28 of the flow housing 10, so that this inner space 44 is filled with the fluid regulated by the valve body 20, while an outer space 47 separated by the containment can, in which the stator 38 is arranged, is dry and protected against external influences.

Furthermore, a gear 46 in the form of a planetary gear is arranged axially between the collar 43 of the containment can 32 and the valve body 20 in the interior space 44, by means of which the movement of the actuator 34 is transmitted to the valve body 20 in a reduced manner.

The planetary gear 46 consists of a sun gear 48, which is fastened to the actuator shaft 22 and is formed in one piece with a rotor carrier 52, at the end of which on the outer circumference is opposite to the sun gear 48 the magnets of the rotor 40 are fastened. The sun gear 48 meshes with two planetary gears 50, one on axes 54 Planet carrier 56 are mounted. The planet gears 50 engage in a stationary ring gear 58 which is formed on the inside of the actuator housing 42. The planet carrier 56 is firmly connected to the valve body 20, so that the movement of the rotor 40 is transmitted to the valve body 20 via the planetary gear 46 in a stepped manner.

The interior 44, in which the gear 46, the rotor 40 and the valve body 20 are located, is filled with the fluid to be conveyed. This means that all rotating parts are arranged in this interior space 44, so that no seal has to be made along the rotating parts. Only the flow housing 10 is sealed to the outside with respect to the actuator housing 42, which, however, are both stationary, so that a static seal can be used. Accordingly, dynamic seals can be completely dispensed with.

In order to be able to regulate the valve body 20 very precisely and sensitively, the valve device has a position feedback unit for determining the rotor position of the electric motor 35, which in the present embodiment consists of a permanent magnet sensor 62, which is radially inside the rotor 40 adjacent to the receptacle 29 for the end of the actuator shaft 22 is attached to the containment shell 32 via a magnet carrier 64 and a first position sensor 66 is made. On the side of the can 32 opposite to the receptacle 29 of the can 32, the position sensor 66, which can be a Hall sensor, for example, is arranged on the central axis of the actuator 34. In this position sensor 66, the rotating magnetic field of the encoder magnet 62 is converted in a known manner into a voltage which represents a measure of the rotational position of the rotor 40 and the actuator shaft 22. The position sensor 66 is arranged on a circuit board 68, which is fastened in the outer space 47, which is closed by a cover 67 and otherwise delimited by the actuator housing 42 and the containment can 32 becomes. In addition to the position sensor 66, the circuit board 68 also carries a control unit 69 with power modules for controlling the electric motor 35, so that the stator 38, which is also arranged in the outer space 47, is connected directly to the circuit board 68 and can be controlled.

As a result of the design of the actuator 34 as a two-phase claw-pole motor with four pole pairs per phase, no magnetic field arises on the central axis of the actuator 34, on which the position sensor 66 is also arranged, as a result of the energization of the stator and the rotation of the rotor 40, as this occurs the axis of rotation always picks up exactly. As a result, only the magnetic field of the encoder magnet 62, whose rotational position always corresponds exactly to the rotational position of the actuator shaft 22, acts on the position sensor 66 largely without interference.

Alternatively, however, the rotor position can also be determined by means of other, sensorless position feedback units. For example, the use of back EMF is also known for this, which can be done in a known manner based on models or by determining the zero crossings of the induced voltage, so that current or voltage sensors or meters are used whose measured values are compared with the values of the control unit in this Determination of the rotor position can be processed. However, since the actuator shaft 22 and with it the rotor 40 complete several revolutions while the valve body 20 only rotates or partially rotates, it is necessary to define a reference point in order to be able to determine the position of the valve body 20 exactly. For this purpose, according to the invention, a magnetizable metal ring 70 is arranged in the valve body 20, which is inserted during the injection molding of the valve body 20. This has individual, radially extending tooth-shaped transmitter elements which serve as magnetizable transmitter elements 72, which interacting with a valve position sensor 74, which in the present exemplary embodiment is designed as a Hall sensor with permanent magnets 75 arranged on the sensor 74. The magnetic field that acts on the valve position sensor 74 is changed accordingly by passing a tooth-shaped transmitter element 72, so that a signal is generated at the valve position sensor 74 that switches between 0 and 1, depending on whether a tooth-shaped transmitter element is opposite it 72 is arranged or not. The tooth-shaped transmitter elements 72 are designed at different distances from one another and with different widths, so that a clear assignment of the position of the valve body 20 to a specific angle of rotation section based on the angle covered and the switching sequence is possible by means of the valve position sensor 74. The valve position sensor 74 is arranged in the actuator housing 42 axially opposite the metal ring 70 and is connected to the circuit board 68 or the control unit 69. Correspondingly, the signals from position sensor 66 and valve position sensor 74 are used for position feedback. The valve position sensor 74 serves to establish one or more reference points from which the further rotation of the valve body 20 can be calculated using the measured values of the position sensor 66. The rotational position of the valve body 20 can thus be determined very precisely, since the position feedback unit achieves a very high resolution with respect to the valve body 20, since it makes several rotations depending on the translation, while the valve body 20 is rotated only once. Thus, starting from the reference point established by the valve position sensor 74, the position determined in the position feedback unit can always be assigned exactly to an exact position of the valve body 20 so that it can be adjusted very precisely and sensitively. The entire electronics can be placed in the area facing away from the valve body 20 and the exact position of the valve body 20 can still be detected. It should be clear that various modifications in comparison to the exemplary embodiment described are obvious to the person skilled in the art without departing from the scope of protection of the main claim. In this way, the inlet and outlet can also be arranged opposite one another or in a different manner, or several inlets and outlets can be formed, so that the throughflow opening or openings are correspondingly placed differently in the rotary valve member. A flap can also be used as a valve body. Of course, the design of the transmission can also be changed, for example a spur gear can be used. A multi-part design of the is also conceivable

Rotary slide member with the planet carrier or a version with another gear, such as a Wolfrom gear, in which the planet gears can be floating and with which significantly higher reductions than in the embodiment shown can be achieved. The encoder magnet could also be attached to the rotor or the rotor position could be determined without a sensor. In particular, however, various sensors can be used. The valve position sensor can also be a continuously operating sensor, creating a redundant system, which enables the measured values to be compared and thus to detect errors or to increase the accuracy of the measurements. In addition to the tooth-shaped transmitter elements, permanent magnets can also be used directly as transmitter elements to change the magnetic field acting on the valve position sensor. Further design changes are of course also conceivable.

Claims

PATENT CLAIMS

1. Valve device with an actuator (34) which has an electric motor (35) with a driven rotor (40), a valve body (20) which can be driven by means of the actuator (34), a position feedback unit (62, 66) on the electric motor (35) , via which a position of the rotor (40) can be determined, characterized in that the valve device has a valve position sensor (74) which generates a signal from a magnetic field that changes due to the rotation of the valve body (20).

2. Valve device according to claim 1, characterized in that the valve position sensor (74) is a switch which switches to a reference position of the valve body (20) when a transmitter element (72) is passed.

3. Valve device according to claim 2, characterized in that the valve position sensor (74) is a Hall switch which interacts with a permanent magnet attached to the valve body (20) or is a Hall switch with a permanent magnet (75) which is equipped with a magnetizable element as a transmitter element ( 72) cooperates on the valve body (20).

4. Valve device according to claim 3, characterized in that a plurality of permanent magnets or a plurality of transmitter elements (72) through which the valve position sensor (74) switches are attached to the valve body (20).

5. Valve device according to claim 4, characterized in that the transmitter elements (72) have different widths or are arranged distributed over the circumference at a different distance from one another.

6. Valve device according to one of the preceding claims, characterized in that the position feedback unit (62, 66) and the valve position sensor (74) are connected to a control unit (69), the control unit (69) being determined by means of the valve position sensor (74) Reference position calculated based on the determined data of the position feedback unit (62, 66) the further rotation.

7. Valve device according to one of the preceding claims, characterized in that the position feedback unit of the electric motor is formed by a position sensor (66) in which by a magnetic field of the electric motor (35) or a transmitter magnet (62) on the rotor (40) or on an actuator shaft (22) can generate a voltage which corresponds to the position of the rotor (40) or the actuator shaft (22).

8. Valve device according to claim 6, characterized in that the position feedback unit of the electric motor (35) is formed by the control unit (69) of the electric motor (35) and an ammeter or voltmeter, via which a model based EMK method or EMK method with zero crossing the rotor position can be determined.

9. Valve device according to one of the preceding claims, characterized in that a gear (46) is formed between the rotor (40) and the valve body (20).

10. Valve device according to one of the preceding claims, characterized in that the electric motor (35) is electronically commutated and the position sensor (66) detects the position of the permanent magnetic rotor (60) and the signal from the position sensor (66) for commutation of the electric motor (35) ) is being used.

11. Valve device according to one of the preceding claims, characterized in that the valve body (20) is a rotary slide valve.