ROTARY ADJUSTER WITH IMPROVED OPTICAL ROTARY POSITION DETECTION

Abstract

The present disclosure relates to a rotary adjuster, including: a housing, a rotary knob mounted in a rotatable manner about a rotation axis (A) on the housing; an optical detection device for detecting a rotary position of the rotary knob and a coding shutter moving synchronously with the rotary knob, wherein the detection device has an optical transmitter and an array of optical receivers, and wherein the coding shutter and the detection device are designed to detect the rotary position of the rotary knob by means of the number of the receivers of the array illuminated by the transmitter and/or by means of an illumination intensity of one or more receivers of the array.

Claims

1. A rotary adjuster, comprising: a housing, a rotary knob mounted in a rotatable manner about a rotation axis (A) on the housing, an optical detection device for detecting a rotary position of the rotary knob and a coding shutter moving synchronously with the rotary knob; wherein the detection device has an optical transmitter and an array of optical receivers, and wherein the coding shutter and the detection device are designed to detect the rotary position of the rotary knob by means of the number of the receivers of the array illuminated by the transmitter and/or by means of an illumination intensity of one or more receivers of the array, wherein the rotary adjuster has a light guide disposed in the beam path between the transmitter and the receivers and moving synchronously with the rotary knob, characterized in that the light guide is configured as a rotationally symmetric body in its section extending between the receiver and the array and is mounted in a rotatable manner about its axis of rotational symmetry.

2. The rotary adjuster of claim 1, wherein the rotary knob and the light guide are arranged coaxially.

3. The rotary adjuster of claim 1, wherein the light guide forms an axis section of the rotation axis (A) of the rotary knob.

4. The rotary adjuster of claim 1, wherein an end section of the light guide, together with the housing, forms a point bearing arrangement.

5. The rotary adjuster of claim 1, wherein another axis section of the rotating axis (A) is connected to the light guide by means of a plug-in connection.

6. The rotary adjuster of claim 1, wherein the array is defined by a single-line assembly extending in the direction of the rotation axis.

7. The rotary adjuster of claim 1, wherein the light guide and the array are disposed in such a manner that a sub-set of the receivers is able to receive light of the receiver independently of the position of the coding shutter, wherein the light guide and the array protrude over the coding shutter.

8. The rotary adjuster of claim 1, wherein the coding shutter has a latching contour into which a latching member on the housing engages.

9. The rotary adjuster of claim 1, wherein the coding shutter is configured as a ring surrounding the light guide and preferably forms a coding contour, such as a saw-tooth contour, on its end face.

10. Use of the rotary adjuster according to claim 1, in a motor vehicle.

Description

[0020] The present disclosure is explained further with reference to the following figures. The Figures are to be understood only as examples and merely represent a preferred embodiment. In the figures:

[0021] FIG. 1 shows a vertical schematic cross-sectional view through an embodiment of the rotary adjuster of the present disclosure;

[0022] FIG. 2 shows a schematic exploded view of the embodiment of the rotary adjuster of the present disclosure shown in FIG. 1;

[0023] FIG. 3 shows a schematic detailed view of the rotary adjuster of the present disclosure from FIG. 1.

[0024] FIG. 1 shows an embodiment of the rotary adjuster 1 of the present disclosure. It has a two-part housing with the housing parts 3a and 3b. The two housing parts 3a and 3b are mutually fixed by means of latching means. The rotary adjuster 1 has a rotary knob 2 which is mounted in a rotatable manner about an axis A on the housing 3a, 3b via a first axis section 14 consisting of an opaque plastic material and a second axis section consisting of transparent plastic material forming a light guide 10. The first axis section 14 is supported on the housing by means of a collar-like projection 18. The first axis section 14 and the light guide 10 functioning as a second axis section are connected to each other by means of a positive plug-in connection and define the rotation axis A of the rotary knob 2. The light guide 10 is configured to be rotationally symmetric about the rotation axis A as the axis of rotational symmetry and has at its end facing away from the rotary knob 2 a conical recess 11, into which a spike 12 on the housing engages in order thus to effect a self-centering point bearing arrangement of the rotary knob 2 and the light guide 10. A coding ring 9 is connected via latching members to the light guide 10 in a non-rotatable manner. On its outer circumference, the coding ring 9 has a latching contour 8 into which a latching spring provided as a latching member 7 engages in an elastically biased manner in order to fix the rotary knob 2 at predefined positions in a latching manner, and in order to generate residual haptics during the rotary operation of the rotary knob 2. The basic structure becomes clear from the exploded view of FIG. 2. The rotary position detection is illustrated by means of FIG. 3. Light of an optical transmitter 4 disposed on a circuit board 7 is coupled into the light guide 10 via the outer circumference of the substantially cylindrical light guide 10, specifically via a first cylindrical lateral surface 13 of the light guide 10, in order to propagate in the light guide 10 and to exit at a location offset in the axial direction A via a second cylindrical lateral surface of the light guide 10 and to be received by an array 5 of optical receivers, in this case a single-line array 5 extending parallel to the rotation axis and combined to form an assembly group. The transmitter 4 and the receiver 5 are stationary while the light guide 10 rotates above the detection device consisting of the transmitter 4 and the receiver 5 during the rotary operation. The first lateral surface 13 is offset towards the outside relative to the second lateral surface 19 and forms a contact flange for the ring-shaped coding shutter 9.

[0025] Due to its self-centering bearing arrangement and the rotational symmetry, the light passage through the light guide 10 is largely independent of the position of the rotary knob 2, whereas the light exiting from the light guide 10, due to the saw tooth-like coding contour 16 formed in the coding ring 9, is blocked out or let through according to position for the purpose of position detection, so that a position detection is possible with the number of the illuminated receivers of the array 5 and with the illumination intensity attained in the process.

[0026] As can be seen in FIG. 3, the saw tooth-shaped coding contour 16 has a periodicity of 90. The transmitter 4 and the array 5 of receivers are disposed on a common circuit board 6 and are disposed along a direction parallel to the rotation axis A. As FIG. 3 also shows, the light guide 10 and the array 5 protrude over the ring-shaped coding shutter 9. Even though a calibration is, in principle, dispensable due to the high level of symmetry and the bearing arrangement of the light guide 10, which is precise because it is self-centering, the unblocked light from the protruding part 17 of the light guide 10 transmitted to the protruding part of the array 5, in addition to the function of merely monitoring function, may also be used for calibration in order to compensate aging phenomena of the transmitter 4 and the receivers 5, for example.