Control element with a rotatably mounted actuating part and an electrically controlled brake for generating an end stop, and associated use

Abstract

The invention relates to an operating element (1) comprising: a housing (3); an actuating part (2) mounted rotatably on the housing (3) about a pivot axis (14) for performing a rotary adjustment by an operator; a position encoder (4) fixed to the actuating part (2) and / or moving synchronously with the actuating part (2) during the rotary adjustment; a position sensor (5) fixed to the housing (3) and cooperating with the position encoder (4); an electrically controllable brake (6, 7, 8) acting between the housing (3) and the actuating part (2) and blocking the rotary adjustment of the actuating part (2); a control unit (15) electrically connected to the position sensor (5) and the brake (6, 7, 8) for position-dependent control of the brake (6, 7, 8) in order to specify a first end stop for the rotation adjustment of the actuating part (3) in a first direction of rotation by blocking the brake (6, 7, 8);wherein the brake (6, 7, 8) is supported on the housing (3) with rotational play (S) so that a rotational adjustment of the actuating part (2) in a second direction of rotation of the actuating part (2) and the locking electric brake (6, 7, 8) is enabled; wherein the control unit (15) is configured, in the event of a detection of a rotational adjustment in the second direction of rotation by the position sensor (5), to at least temporarily release the braking effect of the locking electric brake and to release the rotational adjustment of the actuating part in the second direction of rotation; and related use.

Description

[0001] The invention relates to an operating element with a rotatably mounted actuating part, also called a handle or rotary knob, and an electrically controllable brake for generating an end stop. Such operating elements are also referred to as rotary actuators. According to the invention, means for generating a detent are also provided. In motor vehicles today, a multitude of operating functions must be set, with a trend toward performing these numerous operating functions using a single rotary actuator in order to set parameters or select between different options according to a selected operating function.While in certain operating situations a rotary knob that can be rotated freely in both directions is preferred, in other operating situations when setting parameters or selecting predefined options it is preferable to receive haptic feedback in the form of a multitude of light clicks that can be felt on the rotary knob. In rotary knobs, these are usually implemented in the form of a mechanical contour with an associated spring element. This means that the spring rests against the contour with a mechanical preload and slides up and down when the rotary knob is operated. This sliding movement is disadvantageously associated with friction and is subject to wear and can also cause unwanted grinding noises.If a universal use of the rotary actuator in various operating situations is desired and since switching off this mechanical locking effect is difficult to achieve, electrically controllable brakes with associated control are used, whereby the electrically controllable brake is controlled position-dependently on the basis of the position information received from a position sensor.

[0002] Until now, it was not possible to create an end stop without additional sensors, as the actuating part is trapped in the end stop position without detection of the direction of torque caused by the actuation. A further disadvantage of the designs known from the prior art is that the effect of a "rotation lock" when rotating only slowly can only be perceived by a user if the torque curve of a detent spring is precisely simulated by the control electronics - i.e. a rotational position-dependent current must be applied to the electrically controllable brake for an extended period of time. This usually leads to unpleasant heating of the electrically controllable brake and the actuating part and also requires extremely precise sensors and control.

[0003] The invention is therefore based on the object of providing an operating element, in particular for a motor vehicle, with a rotatably mounted actuating part and an electrically controllable brake with improved generation of at least one end stop for the rotary adjustment, which is structurally simple, is therefore inexpensive to manufacture and in particular requires comparatively little installation space.

[0004] This object is achieved by an operating element according to claim 1. Advantageous embodiments can be found in the subclaims. It should be noted that the features listed individually in the claims can be combined with one another in any technologically expedient manner and demonstrate further embodiments of the invention. The description, particularly in conjunction with the figures, further characterizes and specifies the invention.

[0005] The invention relates to an operating element, in particular for a motor vehicle. The operating element has a housing. The housing is made, for example, from a plastic, such as a thermoplastic. The term "housing" is to be interpreted broadly and can have a design directed solely at the attachment of the operating element. However, it can also have a design that protects an individual component, for example, an electronic component, of the operating element. For example, it is designed in some areas as a substantially closed housing.

[0006] The operating element according to the invention further comprises an actuating part which is mounted on the housing so as to be rotatable about a rotation axis and is also referred to below as a rotary actuator. The actuating part is made, for example, from a plastic, such as a thermoplastic, and is produced, for example, using an injection molding process. The rotation axis is oriented, for example, orthogonal to a user interface facing the operator. The actuating part is preferably designed as a thumbwheel, i.e. operation is achieved using one-finger operation and, for example, the rotation axis lies in the plane of the user interface facing the operator or is parallel to this user interface. The user interface is defined, for example, by the dashboard or a steering wheel into which the operating element is integrated.

[0007] According to the invention, a position sensor is also provided, which is fixed to the actuating part and / or moves synchronously with the actuating part during its rotational adjustment, as well as a position sensor, which is fixed to the housing and interacts with the position sensor. These together form the detection means and serve to detect the position of the actuating part. For example, the detection means is a potentiometer or non-contact detection means, such as optical detection means, are provided. The detection means are designed, for example, as absolute value encoders or as incremental encoders. For example, the position sensor is rotationally driven by the actuating part via a gear transmission.

[0008] According to the invention, an electrically controllable brake is provided which acts between the housing and the actuating part and blocks the rotational adjustment of the actuating part.

[0009] According to the invention, a control unit is further provided, electrically connected to the position sensor and the electrically controllable brake, for position-dependent control of the electrically controllable brake in order to specify a first end stop for the rotary adjustment of the actuating part in a first direction of rotation by blocking the electrically controllable brake. For example, the blocking effect is designed such that at least the manual rotary adjustment is counteracted by a corresponding braking effect, which is perceived as insurmountable, at least by the operator. For example, the blocking torque in the end stop position is 5 N / m or more.

[0010] According to the invention, the electrically controllable brake is supported on the housing with rotational play, allowing rotational adjustment of the actuating part in a second direction of rotation of the actuating part and the blocking, electrically controllable brake, opposite to the first direction of rotation. Furthermore, the control unit is configured to at least temporarily cancel the braking effect of the blocking, electrically controllable brake and enable rotational adjustment of the actuating part in the second direction of rotation if the position sensor detects a rotational adjustment in the second direction of rotation.As a result, a comparatively simple structural design in combination with a comparatively low-wear brake design, such as the electrically controllable brake according to the invention, makes it possible to realize an end stop for an actuating part, wherein the electrically controllable brake also allows the end stop to be specified variably depending on the operating situation specifications.

[0011] Preferably, the actuating part is only rotatably mounted on one side directly on the housing via a first bearing point, while on the opposite side, for example, the actuating part is supported on the housing via the electrically controllable brake, for example with rotational play on the housing.

[0012] Preferably, the electrically controllable brake is supported on the housing by an elastic preloading means.

[0013] Preferably, the control unit is designed to specify a second end stop for the rotational adjustment of the actuating part in a second direction of rotation by blocking the electrically controllable brake.

[0014] Preferably, the control unit is further configured to effect position-dependent modulated braking of the electrically controllable brake during the rotary adjustment to generate a haptic locking effect that is perceptible to the operator. The maximum braking torque is below the blocking torque acting in the end stop position.

[0015] For example, the electrically controllable brake is one that has a piezo actuator for effecting the locking. The electrically controllable brake is preferably an electromagnetic brake, i.e., a brake in which locking is effected or released by energizing an exciter with an electrical operating current. More preferably, the electrically controllable brake embodied as an electromagnetic brake is designed to effect locking by means of an electrical operating current from the control unit. This means that the locking torque is achieved when the brake exciter is "active."

[0016] Preferably, the exciter of the electrically controllable brake designed as an electromagnetic brake has a coil and a magnetic core, wherein the magnetic core is supported on the housing, more preferably supported on the housing via the positive connection having the rotational play.

[0017] Preferably, the actuating part forms a hollow volume in which the electrical exciter, for example the coil, of the electromagnetic brake, and more preferably also the brake disc, is arranged.

[0018] Preferably, an axis is fixed to the magnetic core, on which the actuating part is rotatably mounted. The actuating part has a brake disc that magnetically interacts with the magnetic core.

[0019] The electrically controllable brake preferably comprises a magnetorheological fluid, which is preferably arranged between the magnetic core and the brake disc. A magnetorheological fluid is a suspension of magnetically polarizable particles (carbonyl iron powder) finely dispersed in a carrier fluid. This fluid prevents dirt from penetrating the space between the magnetic core and the brake disc and also reduces an annoying clicking noise when the brake disc and magnetic core collide during brake activation. Due to the magnetic properties of this fluid, the braking effect is only slightly altered.

[0020] A second bearing point for the rotational movement of the actuating part about the axis of rotation is preferably provided between the magnetic core and the actuating part.

[0021] The invention further relates to the equally advantageous use of the control element in one of the previously described embodiments in a motor vehicle.

[0022] The invention is explained in more detail with reference to the following figures. These figures are to be understood as examples only and represent preferred embodiments. They show: Fig. 1 a sectional view parallel to the rotation axis 14 of an embodiment of the operating element according to the invention; Fig. 2 a further sectional view orthogonal to the axis of rotation 14 along the section line AA of the embodiment in Fig. 1.

[0023] An embodiment of the control element 1 according to the invention, also called a rotary actuator, is described below with reference to the Fig. 1. It comprises an actuating part 2, also called a handle, which is mounted on a housing 3 for rotation about a rotation axis 14. In the embodiment shown, the actuating part 2 is designed as a thumbwheel, i.e., operation is achieved by one-finger operation, and the rotation axis 14 is parallel to a user interface 13 facing the operator. The user interface 13 is defined, for example, by the housing 3, as shown.

[0024] Furthermore, a position sensor 4, for example a perforated disc, is provided on the actuating part 2, as well as a position sensor 5, such as a light barrier, to enable position detection of the actuating part 2. Alternatively to securing the position sensor 4 to the actuating part 2, a gear can be provided to achieve synchronous movement of the position sensor 4 with the actuating part 2 during its rotational adjustment. The position sensor 5 is secured to the housing 3. Furthermore, an electrically controllable brake 6, 7, 8, designed as an electromagnetic brake, acting between the housing 3 and the actuating part 2, blocking the rotational adjustment of the actuating part 2, is provided.

[0025] Furthermore, a control unit 15 is provided, which is electrically connected to the position sensor 5 and the electrically controllable brake 6, 7, 8 designed as an electromagnetic brake, for the position-dependent control of the electromagnetic brake 6, 7, 8 in order to specify a first end stop in a first end stop position of the actuating part and a second end stop in a second end stop position, different from the first end stop position, for the rotary adjustment of the actuating part 2 in a first direction of rotation and in a second direction of rotation opposite to the first direction of rotation by blocking the electrically controllable brake 6, 7, 8. For example, the blocking effect is designed such that at least the manual rotary adjustment is counteracted by a corresponding braking effect, which is perceived as insurmountable at least by the operator.For example, the blocking torque in the end stop position specifying the respective end stop is 5 N / m or more.

[0026] The electrically controllable brake 6, 7, 8, designed as an electromagnetic brake, is supported on the housing 3 with rotational play S, so that a rotational adjustment of the actuating part 2 is possible both in the first end stop position in a second direction of rotation of the actuating part 2 and the blocking, electrically controllable brake 6, 7, 8, which is opposite to the first direction of rotation, and in the second end stop position in a first direction of rotation opposite to the second direction of rotation. Furthermore, the control unit 15 is designed, if a rotational adjustment from the first end stop position in the second direction of rotation or a rotational adjustment from the second end stop position in the first direction of rotation is detected by the position sensor 5, to at least temporarily cancel the braking effect of the blocking, electrically controllable brake 6, 7, 8 and to enable the rotational adjustment of the actuating part in the second orfirst direction of rotation. This makes it possible to implement an end stop for an actuating part 2 through a comparatively simple structural design in combination with a comparatively low-wear, electrically controllable brake 6, 7, 8 designed as an electromagnetic brake. The electrically controllable brake 6, 7, 8 also allows the end stop and thus the extent of the maximum possible rotational adjustment of the actuating part 2 to be specified variably depending on the operating situation.

[0027] In the embodiment shown, the actuating part 2 is only rotatably mounted on one side directly on the housing 3, while on the opposite side the actuating part 2 is supported on the housing 3 via the electrically controllable brake 6, 7, 8 with the aforementioned rotational play S. The actuating part 2 has a hollow volume in which the electrical exciter 7, 8, here the coil 7 entirely and the magnetic core 8 at least partially, are arranged. The electrically controllable brake 6, 7, 8, designed as an electromagnetic brake, is configured to effect blocking by means of an electrical working current from the control unit 15. This means that the blocking torque is achieved when the exciter 7, 8 of the electrically controllable brake 6, 7, 8, designed as an electromagnetic brake, is active.In order to ensure the rotational play S, the electrically controllable brake 6, 7, 8 is supported on the housing 3 by an elastic pretensioning means 10, here an annular elastomer component, while the magnetic core 8 is supported on the housing 3 via the positive connection with its pin 11 having the rotational play D, which can be seen in the sectional view of the . Fig. 2. An axis 9 is fixed to the magnetic core 8, on which the actuating part 8 is rotatably mounted. The actuating part 2 has a brake disc 6 that magnetically interacts with the magnetic core 8. To facilitate the relative rotation of the actuating part 2 relative to the exciter 7, 8 when the exciter 7, 8 is de-energized and the electrically controllable brake 6, 7, 8 is thus not blocking, a thrust ring 12 is arranged between them.

[0028] Furthermore, the control unit 15 can be configured to effect position-dependent modulated braking of the electrically controllable brake 6, 7, 8 during the rotational adjustment of the actuating part 2 to generate a haptic locking effect that is perceptible to the operator. The maximum braking torque is below the blocking torque acting in the end stop position.

Claims

[1] Control element (1), comprising: a housing (3); an actuating part (2) mounted on the housing (3) so as to be rotatable about a rotation axis (14) for carrying out a rotational adjustment by an operator; a position sensor (4) fixed to the actuating part (2) and / or moving synchronously with the actuating part (2) during the rotary adjustment; a position sensor (5) fixed to the housing (3) and cooperating with the position transmitter (4); an electrically controllable brake (6, 7, 8) acting between the housing (3) and the actuating part (2) and blocking the rotational adjustment of the actuating part (2); a control unit (15) electrically connected to the position sensor (5) and the electrically controllable brake (6, 7, 8) for position-dependent control of the electrically controllable brake (6, 7, 8) in order to specify a first end stop for the rotational adjustment of the actuating part (3) in a first direction of rotation by blocking the electrically controllable brake (6, 7, 8); wherein the electrically controllable brake (6, 7, 8) is supported on the housing (3) with rotational play (S), so that a rotational adjustment of the actuating part (2) in a second direction of rotation, opposite to the first direction of rotation, of the actuating part (2) and of the blocking, electrically controllable brake (6, 7, 8) is possible; wherein the control unit (15) is designed, in the event of detection of a rotational adjustment in the second direction of rotation by the position sensor (5), to at least temporarily cancel the braking effect of the blocking, electrically controllable brake (6, 7, 8) and to release the rotational adjustment of the actuating part (2) in the second direction of rotation. [2] Operating element (1) according to claim 1, wherein the electrically controllable brake (6, 7, 8) is supported on the housing (3) via a positive connection with rotational play (S). [3] Operating element (1) according to one of the preceding claims, wherein the electrically controllable brake (6, 7, 8) is supported on the housing (3) by an elastic pretensioning means (10). [4] Operating element (1) according to one of the preceding claims, wherein the control unit (15) is designed to specify a second end stop for the rotational adjustment of the actuating part (2) in a second direction of rotation by blocking the electrically controllable brake (6, 7, 8). [5] Operating element (1) according to one of the preceding claims, wherein the control unit (15) is further designed to effect a position-dependent modulated braking of the electrically controllable brake (6, 7, 8) during the rotary adjustment in order to generate a haptic detent that is perceptible to the operator. [6] Operating element (1) according to one of the preceding claims, the electrically controllable brake (6, 7, 8) is designed to effect blocking by means of an electrical working current of the control unit (15). [7] Operating element (1) according to one of the preceding claims, wherein the electrically controllable brake (6, 7, 8) is an electromagnetic brake. [8] Control element (1) according to one of the preceding claims, wherein the electrically controllable brake (6, 7, 8) comprises a magnetorheological fluid. [9] Operating element (1) according to one of the preceding claims, wherein the actuating part (2) defines a hollow volume in which an electrical exciter (7, 8) of the electrically controllable brake (6, 7, 8) designed as an electromagnetic brake is arranged. [10] Operating element (1) according to one of the two preceding claims, wherein the exciter (7, 8) of the electrically controllable brake (6, 7, 8) designed as an electromagnetic brake has a coil (7) and a magnetic core (8), and wherein the magnetic core (8) is supported on the housing (3) via the positive connection having the rotational play (S). [11] Operating element (1) according to one of the preceding claims 7 to 9, wherein an axis (9) is fixed to the magnetic core (8), on which axis the actuating part (2) is rotatably mounted and the actuating part (2) has a brake disc (6) which magnetically interacts with the magnetic core (8). [12] Operating element (1) according to one of the preceding claims, wherein the actuating part (2) is designed as a thumbwheel. [13] Use of the control element (1) according to one of the preceding claims in a motor vehicle.

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