RESET DEVICE FOR A TRANSMISSION SELECTOR LEVER

Abstract

A reset device for a gearshift lever for a gear step of a transmission in a motor vehicle comprises an electric drive device for controlling an operating element, in order to move the gearshift lever into a predetermined position, a position sensor for determining a position of the operating element, and an electric activation device for activating the drive device, depending on the position of the operating element. The position sensor comprises a first coil thereby, which is attached to the activation device, and a magnetic flux element is mechanically coupled to the operating element. The drive device is disposed in relation to the activation device, such that the flux element influences the inductivity of the first coil, depending on a position of the operating element.

Claims

1. A reset device (115) for a gearshift lever (105) for a gear step of a transmission in a motor vehicle, wherein the reset device (115) comprises: an electric drive device (120) for controlling an operating element (125), in order to move the gearshift lever (105) into a predetermined position; a position sensor (130) for determining a position of the operating element (125); and an electric activation device (145) for activating the drive device (120), depending on the position of the operating element (125), characterized in that the position sensor (130) comprises a first coil (135), which is attached to the activation device (145), wherein a magnetic flux element (140) is mechanically coupled to the operating element (125), wherein the drive device (120) is disposed in relation to the activation device (145), such that the flux element (140) influences the inductivity of the first coil (135), depending on a position of the operating element (125).

2. The reset device (115) according to claim 1, wherein the activation device (145) comprises a printed circuit board (155), and the first coil (135) is formed as a conductive path on the printed circuit board (155).

3. The reset device (115) according to claim 1 or 2, wherein the position sensor (130) comprises a second coil (160), which is attached to the activation device (145) such that its inductivity is not influenced by a position of the operating device (125), wherein the position sensor (130) is configured to determine the position of the operating element (125) based on a difference in the inductivities of the coils (135).

4. The reset device (115) according to claim 2, wherein another position sensor (130) is provided for determining a position of the gearshift lever (105), wherein the other position sensor (130) comprises a third coil (165), the inductivity of which is dependent on the position of the gearshift lever (105), the second coil (160) is not influenced by a position of the gearshift lever (105), and the position of the gearshift lever (105) is determined on the basis of a difference in the inductivities of the second and third coil (165).

5. The reset device (115) according to one of the preceding claims, wherein the flux element (140) comprises a section having a magnetically soft material, in order to amplify a magnetic flux of the magnetic field provided by the first coil (135), when the section is brought into proximity with the first coil (135).

6. The reset device (115) according to one of the preceding claims, wherein the flux element (140) comprises a section having an electrically conductive material, in order to reduce a magnetic flux of the magnetic field provided by the first coil (135), when the section is brought into proximity with the first coil (135).

7. The reset device (115) according to one of the claim 5 or 6, wherein an arrangement of numerous sections having flux elements (140) is provided, wherein the sections are moved past the first coil (135) successively when the operating element is operated, wherein the position of the operating element (125) is determined incrementally, based on a temporal course of inductions at the first coil (135).

8. The reset device (115) according to one of the claim 5 or 6, wherein numerous first coils (135) are provided, wherein an arrangement of numerous sections having flux elements (140) is provided, wherein the arrangement is moved past the first coils (135) when the operating element (125) is operated, wherein the position of the operating element (125) is determined absolutely, based on a combination of inductions of the first coil (135).

9. The reset device (115) according to one of the claims 2 to 8, wherein two flux elements (140) are provided, which lie opposite one another with respect to the printed circuit board (155).

10. The reset device (115) according to one of the claims 2 to 9, wherein two first coils (135) are provided, which lie on opposite planes of the printed circuit board (155).

Description

[0019] The disclosure shall now be explained in greater detail with reference to the attached Figures, wherein:

[0020] FIG. 1 shows a control system;

[0021] FIGS. 2-3 show two exemplary mechanical drives;

[0022] FIGS. 4-6 show variations of an assembly for a mechanical drive on the activation device of the reset device from FIG. 1; and

[0023] FIGS. 7-9 show arrangements of flux elements.

[0024] FIG. 1 shows a control system 100 for controlling a transmission in a motor vehicle. By means of a gearshift lever 105 mounted in a monostable manner, a gear step of the transmission can be selected directly or indirectly. For this, the gearshift lever 105 can be brought into different positions 110. In the embodiment depicted by way of example, the positions A1, A2, B1 and B2 are depicted vertically in a right-hand shift gate, which corresponds to an automatic gate for an automatic transmission. Likewise, the position N lies in the right-hand region, which corresponds to a neutral setting of the gearshift lever, into which the gearshift lever automatically returns, due to its monostable mount, in order to assume its starting position, which corresponds to an un-actuated gearshift lever position. It is possible to select at least the gear steps D for forward driving, N for the neutral setting of the transmission, and R for reverse driving though shifting movements in the automatic gate, wherein the gear steps D and R are separated from one another by the gear step N. Other selectable gear steps are possible in the automatic gate. The position A1 represents a forward change from one gear step to the next in this preferred exemplary embodiment, in the sequence of the arrangement of the gear steps, wherein A2 enables a forward change from one gear step to the gear step after the next, by shifting through the gear step lying therebetween. B1 represents a reverse shifting, accordingly, from one gear step to the next, wherein B2 enables a reverse shifting from one gear step to the step after the next, by shifting through the gear step lying therebetween, in the sequence of the arrangement of the gear steps. By way of example, gear steps may be provided, arranged in the sequence R, N, D, wherein the automatic transmission can be shifted into the gear step R, for example. A selection of the position A1 then causes a shifting from the gear step R into the gear step N. The selection of the position A2, in contrast, causes a shifting form the gear step R, via the gear step N, into the gear step D. If the gear step D is to be currently engaged in the automatic transmission, then in contrast, the gear step N can be engaged by selecting the position B1, or the gear step R can be engaged by selecting the position B2, passing through the gear step N.

[0025] In a left-hand shift gate, which corresponds to a manual shift gate, the positions M, T+ and T− are depicted vertically. If the gearshift lever 105 is in the position M, as depicted, then it can be moved by the driver into the position T+, in order to cause an upshifting of the transmission, or in the T− position, in order to cause a downshifting. After releasing it, the gearshift lever 105 normally returns to the position M by means of spring force.

[0026] Regardless of the precise arrangement of different positions 110, the control system 100 is configured to bring the gearshift lever 105 into a predetermined position 110, under predetermined conditions, in particular from a position 110 in the manual shift gate, into a position 110 in the automatic shift gate. In the present circumstances, the gearshift lever 105 can be moved, for example, from the position M into the position N, when the motor vehicle is parked. A reset device 115 is provided for the movement, which comprises an electric drive device 120 and an operating element 125, wherein the drive device 120 is configured to operate the operating element 125, in order to move the gearshift lever 105 into the predetermined position 110. Furthermore, the reset device 115 comprises a position sensor 130, which functions according to the inductive measurement principle.

[0027] The position sensor 130 comprises a coil 135, which is stationary in relation to the drive device 120, and a magnetic flux element 140, which is stationary in relation to the operating element 125. An activation device 145 is configured to activate the drive device 120 in response to a signal from the position sensor 130. The activation can occur in response to a signal, in particular, which can be received at an interface 150. It is preferred thereby that the coil is attached directly to the activation device 145. In particular, it is preferred that the activation device 145 comprises a printed circuit board, onto which the coil 135 is attached. The coil 135 can be designed, in particular, in the form of a printed circuit, wherein a circuit path made of a conductive material is formed in a plane, in concentric windings. It is also possible to provide numerous coils, which are connected to one another, and are disposed in different planes, above one another, and connected electrically to one another.

[0028] The position sensor 130 preferably has the function of a limit switch, which senses in a binary manner whether the operating element 125 has or has not reached a predetermined position. For this, a sensing value can be compared with a threshold value. In other embodiments, a digital position determining using more than two values can also be carried out for the operating element 125. Analog position determinations, i.e. continuous, can also be carried out.

[0029] A differential measurement method can be used, in which another coil 160 is provided, the inductivity, or magnetic field, respectively, of which remains unaffected by a position of the flux element 140. The inductivities of the coils 135 and 160 can then be compared with one another, in order to determine, in an analog or digital manner, the position of the flux element 140, and thus the operating element 125. By way of example, two oscillating circuits can be created with the coils 135 and 160, the frequencies of which can be determined and compared with one another.

[0030] In a particularly preferred embodiment, another one or more coils 165 can be comprised by the reset device 115, wherein the additional coil 165 can be configured for sensing the position of the gearshift lever 105, for example. For this, the gearshift lever can comprise a flux element, or be mechanically coupled to a flux element. It is particularly preferred that the third coil 165 is directly attached to the activation device 145, in particular as a printed coil on the printed circuit board 155.

[0031] FIGS. 2 and 3 show two different mechanical drives, which can be used for transferring a movement of the drive device 120 to the operating element 125. Therein, FIG. 2 shows an exemplary worm gearing, and FIG. 3 shows an exemplary linear drive. In both cases, the drive device 120 comprises an electric motor, which provides a rotational movement. The worm gearing from FIG. 2 supports this movement, and likewise provides a rotational movement, which can be used to reset the gearshift lever 105. The linear drive from FIG. 3 likewise supports the rotational movement of the drive device 120, but provides instead, a linear movement, which can be used to reset the gearshift lever 105. In both cases, an additional gear step can also be used, e.g. in each case between the drive device 120 and the worm. Both of the drives, or types of drives, shown therein can be used with the present disclosure.

[0032] FIGS. 4 and 5 show variations of an assembly of a mechanical drive, which provides a rotational movement at the activation device 145 of the reset device 115 from FIG. 1. According to the embodiment in FIG. 4, it can be determined that the operating element 125 has reached a predetermined position when the flux element 140 is located at a limited distance to the coil 135. For this, the flux element 140 is brought within a radius surrounding a rotational axis 405, about which the mechanical drive provides the rotational movement for resetting the gearshift lever 105. In the present illustration, the lever is designed, by way of example, as a cam or an eccentric tappet, which can directly support the operating element 125. In another embodiment, a separate element is provided for supporting the operating element 125.

[0033] A complementary embodiment to the embodiment in FIG. 4 is illustrated in FIG. 5. It can be determined here that the operating element 125 has reached a predetermined position when the magnetic flux element 140 is removed from the coil 135, which corresponds to a predetermined rotational position about the rotational axis 405.

[0034] In the embodiments in FIGS. 4 and 5, two flux elements can also be provided on different sides of the printed circuit board 155. For this, the lever, the cam, the disk or the eccentric tappet, which retains the flux element 140 in relation to the rotational movement about the rotational axis 405, can be slotted in the plane of rotation, in order to accommodate the printed circuit board 155 in the region of the slot.

[0035] It is possible in general to design the magnetic flux element 140 to either amplify or dampen a magnetic field of the first coil 135. An amplification can be obtained, for example, by means of a magnetically soft material, while a damping can be caused by means of a conductive, preferably non-ferromagnetic material such as copper or aluminum. Eddy currents can be formed in the material thereby, by means of the magnetic field, which reduce the magnetic field, or the magnetic flux. In one embodiment, a mechanical element of the reset device 115 is already formed from an appropriate material, such that the element need only be formed in accordance with one of the options in FIG. 4 or 5, in order to be able to carry out a position determination by means of the coil 135. The material can comprise, by way of example, aluminum or zinc die casting. In another embodiment, a magnetic flux element 140 can be attached at an appropriate point to a moving element of the reset device 115.

[0036] FIG. 6 shows an alternative to the attachment of the magnetic flux element 150 to a rotatable component of the reset device 115, in which the rotational axis 405 is parallel to a plane into which the activation device 145 extends. The magnetic flux element 140 oriented differently than in the embodiments shown in FIGS. 4 and 5 with regard to the rotational axis 405, such that rather than being oriented axially, it is oriented radially thereto. For this, one or more flux elements 140 may be disposed on the outer surface of a cylindrical component, for example. In another embodiment, a cylindrical component may have one or more axial extensions at a predetermined circumference about the rotational axis 405, onto which the magnetic flux element 140 is attached. The cylindrical component can then resemble a crown, wherein the coil 135 is disposed axially such that it lies in the rotational plane in which one or more extensions lie.

[0037] FIG. 7 shows an arrangement of flux elements 140 on a moving element 705, which is mechanically coupled to the operating element 125. The illustrated arrangement can be used alternatively with a moving element 705 that is rotated about the rotational axis 405, or with a moving element that is linearly displaced. Numerous flux elements 140 are attached to the element 705, which can be sensed with numerous coils 135 of the position sensor 130. It is preferred thereby that the coils 135 sense the presence or absence of different magnetic flux elements. In the illustration in FIG. 7, the flux elements are divided into a first track 710 and a second track 715, for example. Each track 710, 715 is assigned to a coil. The coils 135 may be located adjacent to one another in a direction perpendicular to the direction of movement for the moving element 705. A binary encoding of the position of the element 705 can occur. The encoding can support as many bits as there are tracks 710, 715, corresponding to a maximal resolution of 2.sup.n positions for n tracks. With the arrangement shown herein, of two tracks, four different positions of the element 705 can be sensed. In other embodiments, more tracks 710, 715 may be used in order to increase the resolution.

[0038] FIG. 8 shows another variation of moving element 705 from FIG. 7, in which only one track 710 is used. In this case, the flux elements 140 are preferably attached at equidistant positions in the direction of movement. As a result, an incremental sensing of the flux element 140 by means of the coil 135 can occur. The flux elements 140 can be as wide as the gaps between them with respect to the direction of movement of the element 705. In order to increase the resolution, two coils 135 may be used thereby, which are offset in the direction of movement by one half of the width of the flux element 140.

[0039] FIG. 9 shows another alternative arrangement of flux elements 140 on the moving element 705, analogous to the embodiments in FIGS. 7 and 8. In this case, two flux elements 140 of different types are disposed in the same track 710. While the one flux element causes an amplification of the magnetic field, the other is configured to dampen the magnetic field of the coil 135. The two flux elements 140 are tapered, complementary directions, along the direction of movement of the element 705. Depending on the position of the coil 135 in relation to the element 705, the magnetic field of the coil 135 can be affected in a negative or positive manner, or not at all. As a result, an analog, in particular, sensing of the position of the moving element 705 can be carried out. The analog sensed position can also be made discrete, in order to provide a digital position.

REFERENCE SYMBOLS

[0040] 100 Control system [0041] 105 Gearshift lever [0042] 110 Position of the gearshift lever [0043] 115 Reset device [0044] 120 Electric drive device [0045] 125 Operating element [0046] 130 Position sensor [0047] 135 First coil [0048] 140 Magnetic flux element [0049] 145 Activation device [0050] 150 Interface [0051] 155 Printed circuit board [0052] 160 Second coil [0053] 165 Third coil [0054] 405 Rotational axis [0055] 705 Moving element [0056] 710 First track [0057] 715 Second track