WO2018036582A1

WO2018036582A1 - Motor vehicle actuator having a high-resolution absolute sensor

Info

Publication number: WO2018036582A1
Application number: PCT/DE2017/100645
Authority: WO
Inventors: Jürgen GERHART; Peter Greb; Lászlo Mán
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2016-08-25
Filing date: 2017-08-01
Publication date: 2018-03-01
Also published as: DE112017004187A5; DE102016215945A1

Abstract

The invention relates to a motor vehicle actuator (1), such as a clutch actuator (1) or a transmission actuator (1), comprising a stator (2), relative to which a rotor (3) can be rotated in accordance with current flow in order to force an adjusting motion, for example a longitudinal motion, of an actuating element (4), such as a spindle, by means of a rotational motion, wherein an absolute sensor (5), by means of which the absolute position of the actuating element (4) is determined, is used and wherein a controller (6) is used to specify the direction of rotation of the rotor (3), which controller uses the value provided by the absolute sensor (5).

Description

Motor vehicle actuator with high-resolution absolute sensor

The present invention relates to a motor vehicle actuator / actuator, such as a clutch actuator or a gear actuator, with a stator, to which a rotor is flow-dependent rotatable to a rotational movement by an adjusting movement, such as a longitudinal movement of an actuating element, such as a spindle / threaded spindle / spindle rod, to force / effect, wherein an absolute sensor, by means of which the absolute position of the actuating element or the rotor is determined, is used.

From WO 2015/1 17 612 A2 an actuator with a Planetenwälzgewindespindel (PWG) is known, in particular for the actuation of a clutch of a vehicle, with a threaded spindle a plurality of planetary gears are engaged, which mesh with a planetary rollers surrounding ring gear, wherein the Planetary rollers are positioned at both ends in a planetary roller carrier and the planet carrier rotatably supported with a, the ring gear and radially inwardly pointing at both ends sleeve, according to the invention, the sleeve and the planet carrier supported therein axially fixed and rotatably connected to a rotor of a drive and can be driven about an axis of rotation, the threaded spindle is rotatably supported and the threaded spindle performs an axial stroke upon rotation of the rotor and the planet carrier supported in the sleeve. In this case, the rotor side, a signal generator and a stator sensor rotation are arranged.

Likewise, from WO 2015/149 775 A1 a modular actuator concept for clutch actuators is known, in particular clutch and / or transmission actuators, in which a modular concept is proposed. For this purpose, an electric motor with a universal flange is provided. An electro-hydraulic or electromechanical actuation path can then be connected via this flange. By means of the actuator thus created, a clutch and / or a gear setting device can then be actuated. In particular, for use for an electro-hydraulic actuator, the motor housing may still have a receptacle for a pressure sensor. A problem of the current state of the art is that in brushless motors without commutation sensors, the angular adjustment of the rotor at standstill is initially unknown. As a result, the engine can be approached, but the direction of rotation is unpredictable. It is possible to start the engine (on suspicion) and determine by its reaction (direction of rotation) whether the direction is correct or whether the direction of rotation must be changed. In actuators for motor vehicles, however, this method is usually not allowed by principle and it takes time. To start it is therefore necessary to know the relative position of the rotor to the stator, or to the coils, if you do not want to accept reversal in direction or can.

An alternative is the determination of the inductance of the coils at standstill and, moreover, the determination of the rotor position in order to start the engine in the desired direction from a standstill. However, this requires additional, expensive electronic components and the determination of the rotor position also requires time.

It is therefore an object of the invention to remedy the drawbacks of the prior art and at least to reduce and in particular to provide an actuator for a motor vehicle / Kraftfahrzeugaktor available that can predetermine and control a direction of rotation of the rotor to the stator at a standstill.

The object of the invention is achieved in a generic motor vehicle actuator in that a control is used to specify the direction of rotation of the rotor, which uses / sets the value provided by the absolute sensor.

It has surprisingly been found that a motor actuator provided with a rotor and stator (electric motor) according to the invention and equipped with an absolute sensor can already accomplish this task by determining the rotor angular position directly or indirectly at standstill via this absolute sensor and from the sensor Control is used to specify the direction of rotation, whereupon an immediate start of the engine in the desired direction of rotation is possible. In this way, further electronic / electrical components for accurate angular position determination via inductance measurement, such as Hall Sensors omitted, resulting in a cost savings and beyond a reduction in space or space requirements.

Furthermore, a loss of time during startup from standstill compared to actuators with rotor and stator with commutation sensors can be avoided. Also so interpretation problems can be avoided in a design of the magnetic circuit to multiple sensors. The dynamics and availability of the motor vehicle actuator are significantly improved. Advantageous embodiments are claimed in the subclaims and are explained below.

It is expedient if the controller is designed so that it selects the direction of rotation of the rotor relative to the stator in dependence on the displacement direction of the adjusting element. In many automotive actuators, it is necessary that a displacement direction of the adjusting element is maintained, since a reversal of direction is not allowed or not possible. About a selected direction of rotation of the rotor relative to the stator, the adjustment can move in the desired direction / move / twist.

Furthermore, it is advantageous if the absolute sensor is such a high-resolution sensor that a conclusion on the real angular position of the rotor to the stator is possible. By means of such a high-resolution absolute sensor, the real angular position can be detected with sufficient accuracy that the control, after evaluating this absolute value (signal), can approach the rotor relative to the stator from standstill in the desired direction. A correspondingly predetermined by the controller energization allows the rotor to the stator current flow dependent rotate in a predetermined direction. The absolute sensor is preferably designed as an absolute angle sensor or as an absolute path sensor. The absolute angle sensor can determine an absolute angle or an absolute angular position, in particular of the rotor relative to the stator, in order to pass on a real angular position of the rotor to the controller, which corresponds to a relative position of rotor to stator. This relative position is determined so well by the absolute angle sensor, that by a predetermined by the control / controlled (time-dependent) current flow, the direction of rotation is predetermined for starting / for a rotary movement. An absolute path sensor may also be used to unambiguously match one (absolute) path position in an angular recalculation from an absolute path signal of an absolute path sensor in combination with a particularly steep-pitched rotational-linear gear or rotational-linear interaction ) Angular position can be assigned to obtain an absolute angle of the rotor to the stator. This absolute angle again corresponds with sufficient accuracy to a relative, real angular position of the rotor to the stator.

It has proven to be expedient if the absolute sensor is designed so that it determines the relative position of designed as a threaded spindle / spindle rod control element to him. A rotary-linear gear, for example with a threaded spindle as an actuator, is a proven device to interpret a motor vehicle actuator with an axially movable actuator. By determining the position of the threaded spindle relative to the sensor, in particular an absolute position of the threaded spindle and further an absolute angle of the rotor relative to the stator can be determined / determined / calculated. On the relative position of the control element designed as a threaded spindle, the absolute sensor can thus determine a real angular position of the rotor to the stator.

Preferably, the threaded spindle has a linear slope and / or gradient.

In particular, a gradient-loyal rotational-linear gear is used in the motor vehicle actuator or the motor vehicle actuator has such a gradient-true rotational-linear gear for actuating. As a result, an unambiguous assignment of the absolute path / position to the absolute angle is achieved and the absolute sensor can again determine an angular position of the rotor relative to the stator via the gradient accuracy.

Further, it is advantageous if the threaded spindle is free of play with a nut engaged and / or free of play with planets in operative engagement. Through this freedom of play a determined absolute value is not falsified or has an absolute value of a high quality with a correspondingly high resolution in order to correspond to a real angular position of the rotor to the stator or get close enough accurate. Preferably, the actuator is part of a transmission. By a direct determination of the absolute position of the actuating element, which is part of a transmission, it is possible, inter alia, to avoid further measuring errors, such as connection measuring errors or transmission measuring errors. It is expedient if the gear is designed as a (synchronized) Planetenwälzgewindespindel (SPWG / PWG). This Planetenwälzgewindespindel is a proven actuator with a rotor and a stator in which a rotational rotary motion is transferred to a linear translation by means of the Planetenwälzgewindespindel, and which can be made compact. A rotor angular position is determined directly or indirectly at a standstill in order to start a rotational movement of the rotor in the desired direction from a standstill.

It is expedient if the motor vehicle actuator is designed / designed as a modular clutch actuator (MCA). As a result of this modular concept, an electrohydraulic or electromechanical actuation path can be connected, as required, by means of which a modular clutch actuator, for example, can actuate a clutch or a transmission setting device. In other words, the invention relates to an increase in dynamics and availability optimization for a (motor vehicle) actuator in which a sensorless electric motor is used. By evaluating absolute value signals, the motor can be approached from standstill in the desired direction without otherwise required induction regulations and the necessary components. The only condition is that the absolute angle sensor (or the angular recalculation of an absolute path sensor) provides a correspondingly good angular resolution and thus the rotor position available to make the energization of the corresponding coil directly for fast start in the desired direction. To avoid additional components, the invention provides to use an already existing Absolutweg- or absolute angle sensor of the actuator in order to determine the relative position of the rotor at least so precisely that a starting of the motor in the right direction is possible. A use of this sensor for commutation is not provided. For the use of an absolute displacement sensor, a true-pitch rotation-linear gear such as a (synchronized) Planetenwälzgewindespindel (SPWG / PWG) is necessary because only then there is a clear relationship between the linear position of an actuator element and the rotor position. The idea is to use an absolute sensor (eg multiturn) with such a high resolution that the high-resolution Hall sensors can be dispensed with. The advantage lies in cost-technical and technical design advantages, since, for example, the magnetic circuit can be optimized to only one sensor. The invention will be explained in more detail below with reference to preferred embodiments with the aid of figures. Show it:

1 shows a longitudinal section of a motor vehicle actuator with an absolute angle sensor with a Planetenwälzgewindespindel.

Fig. 2 in longitudinal section a motor vehicle actuator with an absolute displacement sensor and a threaded spindle.

The figures are schematic in nature and are intended only to aid understanding of the invention. Identical elements are provided with the same reference numerals. The features of the various embodiments can be interchanged.

1 shows a motor vehicle actuator 1 according to the invention, which has a substantially annular stator 2 with coils, to which an internal rotor 3 is rotatable, to a with the rotor 3 (via a rotary gear) in operative engagement threaded spindle / Spindle rod 4, which serves as an actuator, to move longitudinally or linearly. An absolute sensor 5 which is implemented as an absolute angle sensor 5 'and the absolute angle of the rotor 3 determined relative to the stator 2, transmits / transfers this determined value / this absolute angle to a controller. 6

On the rotor 3, a magnetic ring 7 is arranged as a signal transmitter / sensor detection part on an end face, circumferentially about its axis of rotation or about the axis of the threaded spindle 4. The radial distance of the absolute angle sensor 5 'to the axis of rotation of the rotor 3 or to the axis of the threaded spindle 4 and the radial distance of the magnetic ring 7 to the axis of rotation of the rotor 3 and the axis of the threaded spindle 4 are approximately equal. A (ring) section of the magnet ring 7 is always located in the region or in the immediate axial vicinity of the absolute angle sensor 5 'during a rotation of the rotor 3 and allows conclusions to be drawn about the rotational movement and the absolute, real angular position of the rotor 3 by the absolute angle sensor 5'. , Next, the absolute angle sensor 5 'on a board 8, in particular perpendicular to the axis of rotation of the rotor 3 and to the axis of the threaded spindle 4, mounted, which is disposed within a housing 9 of the motor vehicle actuator 1.

The absolute angle sensor 5 'has such a high resolution that a sufficiently accurate position of the rotor 3 relative to the stator 2 can be determined via the magnet ring 7, which is attached to the rotor 3. It can be determined as an absolute angle, which corresponds to the real (absolute) angular position of the rotor 3. Based on the determined absolute angular position of the rotor 3, the controller 6 can derive a relative position of the rotor 3 relative to the stator 2, for example via a stored table or characteristic curve in the control for a relation of absolute angular position to relative position from the rotor 3 to the stator 2, so that the Control 6 depending on the determined absolute angular position or possibly determined therefrom relative position of the rotor 3, the (initial) energization of the coils of the coils of the stator 2 can make such a way to approach the rotor 3 in a predetermined direction of rotation and then rotate. The motor vehicle actuator 1 uses in this embodiment, a Planetenwälzgewindespindel (PWG) 10 as gradual true rotational-linear gear to convert a rotational movement of the rotor 3 in a linear movement of the threaded spindle 4 / implement. The threaded spindle 4 is rotatably connected at one axial end 1 1 with a guide nut 13, which a Has polygonal outer profile for a rotationally fixed and axial guidance to the housing 9. Likewise, the threaded spindle 4 radially on the outside an external thread 14 which is in engagement with a plurality of planets 12 of the Planetenwälzgewindespindel 10, which rotate upon rotation of the rotor 3 in engagement. A rotation of the rotor 3 leads to a rotation of the Planetenwälzgewindespindel 10. Via the threaded engagement between the axially fixed Planetenwälzgewindespindel 10 and the non-rotatable threaded spindle 4, the rotation of the Planetenwälzgewindespindel 10 to an axial (translational) displacement of the threaded spindle 4 along its longitudinal axis and an axial stroke of the Threaded spindle 4.

The external thread 14 of the threaded spindle 4 has a linear thread, so that via the Planetenwälzgewindespindel 10, which is used as gradual true rotary linear gear, if a reference point / zero point of the threaded spindle 4 is known, based on the absolute angle detected by the absolute angle sensor 5 'absolute angular position Also, an (absolute) linear position of the threaded spindle 4 and the axial position of the threaded spindle 4 can be determined. For this purpose, a relationship of the (absolute) angular position of the rotor 3 to the (absolute) linear position of the threaded spindle 4 is stored in the control 6. The relationship between angular position and linear position can again be stored in particular in the form of a table or a characteristic in the controller 6. Thus, according to the invention with only one absolute angle sensor 5 'on the one hand, the relative position of the rotor 3 to the stator 2 are determined to realize a start / turn of the rotor 3 in a predetermined direction of rotation, and on the other hand, an absolute linear position of the threaded spindle 4 of the motor vehicle actuator 1 for a Actuation be determined.

2 shows a motor vehicle actuator 1 of a second embodiment variant with an absolute sensor 5 designed as an absolute path sensor 5 "which can determine an axial (linear) position of the threaded spindle 4. The absolute path sensor 5" is designed as a sensor module in this variant, which is parallel to the axis of rotation of the rotor 3 and to the axis of the threaded spindle 4 and is arranged radially outside the threaded spindle 4 in the housing 9. At the end facing away from the rotor 3 axial end of the threaded spindle 4, a magnet 7 'as a signal generator is fixed rigidly and without play, which moves with the threaded spindle 4. The magnet 7 'provides a unique magnetic field for the longitudinally extending absolute path sensor 5 "The absolute path or the absolute position of the magnet 7' and thus the threaded spindle 4 can be determined by the absolute path sensor 5" with high resolution.

A gradual rotation-linear gear 15 converts a rotational movement of the rotor 3 into a linear movement of the threaded spindle 4. The threaded spindle 4 in turn has a linear external thread 14. About the unique assignment of the position / the absolute path of the threaded spindle 4 by the gradient-faithful rotary-linear gear and the play-free design of all action interventions of the rotary-linear gear 15 can by means of an angle calculation on the controller 6, in which the relationship of the absolute angular position of the rotor 3 is deposited to the absolute linear position of the threaded spindle 4, an absolute angle, which corresponds to a real (absolute) angular position of the rotor 3 of the rotary-linear gear 15, are determined. By means of a retroactive calculation of the control 6 via the relation of absolute angle to relative angle between rotor 3 and stator 2 stored there, the direction of rotation of the rotor 3 can be predetermined in order to be able to start directly in the desired direction by a predetermined energization of the coils. With the one absolute path sensor 5 ", a relative angular position of the rotor 3 to the stator 2 can be determined indirectly by means of the control 6 in this motor actuator 1 by direct determination of the absolute path of the threaded spindle 4 in order to approach the rotor 3 in the predetermined direction.

It is of course also possible to use the rotor 3 directly or a rotatably connected to the rotor 3 element as an actuating element. Thus, the actuator does not necessarily have a translatory, but can also perform a rotational movement. Also, an external thread 14 of a threaded spindle 4 does not necessarily have to be constant, but can be adapted via different pitches in different sections in the axial direction in accordance with the tasks of the actuator. The only condition is and remains that ultimately an absolute angle or an absolute angular position of the rotor 3 can be assigned to the stator 2 via the rotary linear gear ultimately an absolute path of the control element. One Motor vehicle actuator 1 according to the invention may of course be designed as a modular clutch actuator (MCA) in order to provide a high level of flexibility for various fields of application or further developments.

Furthermore, instead of the magnet ring 7 or the magnet 7 ', it would also be possible to realize an optical marking, for example by means of a circumferential or longitudinal optical identification code, which is detected by an optical detection device as an absolute sensor 5 and used as an absolute value provided to the control 6.

The controller 6 can be any controller, in particular electrotechnical, which is designed to use the value set by the absolute sensor 5 and to offset the rotor 3, which is rotatable relative to the stator 2, selectively in a predetermined rotational direction in a predetermined rotational direction.

Motor vehicle actuator

stator

rotor

actuator

absolute probe

Absolute-angle sensor

"Absolute displacement sensor

control

Signaling device / Sensor detection part / Magnetic ring 'Magnet

circuit board

casing

0 planetary roller screw

1 axial end

2 planets

3 guide nut

4 external threads

5 rotary linear gear

Claims

claims

1 . Motor vehicle actuator (1) with a stator (2), to which a rotor (3) is rotatable depending on current flow to force an adjusting movement of an actuating element (4) by a rotary movement, wherein an absolute sensor (5), by means of which the absolute position of the actuating element ( 4) is used, characterized in that a controller (6) for setting the direction of rotation of the rotor (3) is used, which uses those provided by the absolute sensor (5) value.

2. Motor vehicle actuator (1) according to claim 1, characterized in that the

Control (6) is designed so that it selects the direction of rotation of the rotor (3) relative to the stator (2) in dependence on the displacement direction of the actuating element (4).

3. Motor vehicle actuator (1) according to claim 1 or 2, characterized in that the absolute sensor (5) is such a high-resolution sensor that a conclusion on the real angular position of the rotor (3) to the stator (2) is possible.

4. motor vehicle actuator (1) according to one of claims 1 to 3, characterized in that the absolute sensor (5) as an absolute angle sensor (5 ') or as an absolute path sensor (5 ") is designed.

5. motor vehicle actuator (1) according to claim 4, characterized in that the

Absolute sensor (5) is designed so that it determines the relative position of the threaded spindle (4) designed adjusting element (4) to him.

6. motor vehicle actuator (1) according to claim 1 to 5, characterized in that in the motor vehicle actuator (1) a gradient-true rotary-linear gear (10, 15) is inserted. Motor vehicle actuator (1) according to claim 5 or 6, characterized in that the threaded spindle (4) without play with a nut (13) is engaged and / or play with planet (12) is in operative engagement.

Motor vehicle actuator (1) according to one of claims 1 to 7, characterized in that the adjusting element (4) is part of a transmission.

Motor vehicle actuator (1) according to claim 8, characterized in that the

Gear is designed as Planetenwälzgewindespindel (10).

Motor vehicle actuator (1) according to one of Claims 1 to 9, characterized in that the motor vehicle actuator (1) is designed as a modular clutch actuator (1).