Sensor arrangement for angle detection and gearbox

Abstract

Sensor arrangement for angle detection of a shift fork (50) of a manual transmission, wherein the shift fork (50) is rotatably arranged on a bracket (60), characterized by: - a first sensor element (110) that can be coupled to the shift fork (50) in order to perform a movement relative to the holder (60) in response to a rotation of the shift fork (50); - a second sensor element (120) which can be fixed to the holder (60) in a rotationally fixed manner and which can be coupled to the first sensor element (110) in order to generate a sensor signal when the shift fork (50) is rotated and a resulting relative movement occurs between the first sensor element (110) and the second sensor element (120), which depends on the rotation of the shift fork (50) performed; - an evaluation circuit (130) on which the second sensor element (120) is mounted and which generates a signal based on the sensor signal that indicates an angle of the switching fork (50); and - a housing (150), wherein the second sensor element (120) and the evaluation circuit (130) together with the housing (150) can be fixed to the holder (60).

Description

[0001] The present invention relates to a sensor arrangement for angle detection, to a gearbox and in particular to a sensor arrangement for sensing a rocker fork for a gearbox, in particular of a commercial vehicle.

[0002] Commercial vehicles (e.g., for local and long-distance transport, distribution, and intercity and coach services) often use multi-gear transmissions manufactured using modular systems. This design is increasingly being used for automated manual transmissions in commercial vehicles, with varying degrees of automation. Depending on the specific model, the starting process, clutch engagement, and gear selection can all be automated. With manual transmissions, none of these processes are automated; with semi-automated transmissions, at least one process is automated; and with fully automatic transmissions, all processes are automated.

[0003] Therefore, adapted actuation devices are required for an automated starting clutch, automated clutch engagement during gear changes, and automated gear selection in an engine management system. Of central importance for gear shift automation is the most accurate possible detection of the positions of switching elements in order to further optimize automated shifting processes and increase efficiency.

[0004] In conventional systems, the position of switching elements in gearboxes is determined by detecting linear displacements. Such displacements represent, for example, a desired actuator travel (e.g., for a shift fork) and can be detected, for example, by the piston position within a cylinder.

[0005] In an automated manual transmission, the angular positions of one or more rocker arms are detected and transmitted to a transmission control unit (TCU). It is crucial to determine the position of the rocker arm(s) as precisely as possible and to minimize inaccuracies in the measurement chain. Such inaccuracies can arise, for example, from wear, play, elasticity due to stiffness, and thermal expansion.

[0006] Therefore, there is a need for a sensor arrangement that does not have the aforementioned disadvantages or limitations.

[0007] This technical problem is solved by a sensor arrangement according to claim 1 and a transmission according to claim 10. The dependent claims relate to advantageous embodiments of the subject matter of the independent claims.

[0008] The present invention relates to a sensor arrangement suitable for detecting the angle of a rotatable actuator relative to a mounting, wherein the actuator is rotatably mounted on the mounting. The sensor arrangement comprises (at least) a first sensor element and (at least) a second sensor element. The first sensor element can be coupled to the actuator to initiate a movement (e.g., a rotation) in response to a rotation of the actuator relative to the mounting. The second sensor element can be fixed to the mounting in a rotationally fixed manner and can be coupled to the first sensor element to generate a sensor signal when the actuator rotates and a resulting relative movement (e.g., a rotation) occurs between the first and second sensor elements. This sensor signal depends on the degree of rotation of the actuator.

[0009] The actuating device and the mounting need not be part of the sensor assembly. The actuating device is a shift fork of a transmission to which the sensor assembly can be attached. Within the scope of the present invention, the sensor signal should be as broad as possible and can encompass any change in electrical current or voltage that changes due to movement. This change can be caused by a change in resistance along a current path, an inductive change, or a change caused by the Lorentz force. It can also be an optical signal that changes due to movement.

[0010] Exemplary embodiments of the present invention solve the above-mentioned technical problem by means of a sensor arrangement for the direct detection of a rotation of at least one actuating means of a gear transmission.

[0011] In particular, a magnetic measuring principle can be used. For example, the first sensor element comprises a permanent magnet which generates a changing magnetic field when the actuator is rotated, and the second sensor element is designed to generate the sensor signal in response to a change in the magnetic field.

[0012] The sensor assembly comprises an evaluation circuit and a housing. The second sensor element and the evaluation circuit can optionally be fixed to the mounting bracket together with the housing (e.g., as a self-contained, encapsulated unit).

[0013] In further embodiments, the first and second sensor elements are part of an inductive or magnetic sensor, which may, for example, be a (2- or 3-dimensional) Hall sensor or a magnetoresistive sensor. The magnetoresistive sensor may, for example, be a GMR sensor (giant magnetoresistance), an AMR sensor (anisotropic magnetoresistance), or a TMR sensor (tunnel magnetoresistance).

[0014] However, the present invention is not limited to a magnetic measuring principle. In further embodiments, the first sensor element and the second sensor element are optically coupled to each other, wherein the sensor elements comprise a light source (e.g. a laser), a light sensor and geometric structures (e.g. slots) that interrupt the light signal depending on the relative rotation.

[0015] In further embodiments, the sensor arrangement optionally includes a gearbox that couples the first sensor element to the actuator. This makes it possible to translate a rotational angular range of the actuator into a larger angular range of the first sensor element, thus enabling a higher angular resolution.

[0016] In further embodiments, the first sensor element is fixed directly to the actuating device without a coupling element, such as a gearbox.

[0017] In further embodiments, the sensor arrangement also includes a temperature sensor for detecting a temperature in order to perform a correction based on the detected temperature. The temperature sensor can be a separate component or integrated into a chip. Detecting the temperature is important, for example, for optimizing the execution of a shifting process in a transmission. Besides temperature-related expansion, the consistency of a transmission fluid also depends on the temperature. The transmission control unit can take this data into account and evaluate a detected rotation angle differently depending on the temperature.

[0018] The present invention also relates to a sensor system that can be coupled to a control unit. The sensor system comprises (at least) a first sensor arrangement and (at least) a second sensor arrangement as previously defined. Furthermore, the sensor system comprises a bus system configured to transmit data between the first / second sensor arrangement and the control unit. For this purpose, a universal interface can be used, for example, which can be employed for a large number of sensors. This allows embodiments to be adapted to various switching concepts.

[0019] The present invention also relates to a manual transmission with a sensor arrangement or sensor system as previously defined and a control unit. The actuating means can optionally be a shift fork, and the control unit can be configured to control the shifting of the manual transmission and to evaluate sensor signals from the sensor arrangement. In particular, the control unit can indicate a shift state of the manual transmission.

[0020] In further embodiments, the transmission includes an additional sensor designed to detect movement of the shift fork, so that the additional sensor and the sensor arrangement are redundant to meet safety-related requirements.

[0021] In further embodiments, the transmission includes a control unit designed to convert the detected rotary sensor signal (indicating an angle of rotation) into a distance traveled or a linear motion, thus determining the position of a shift fork within the transmission. This conversion can be defined by appropriate calibration, in which a detected angle of rotation is assigned to a linear offset that ultimately triggers the shifting process. This assignment can change over time, for example, due to wear. This can be compensated for by a software-based learning process. Furthermore, this assignment can also depend on temperature (e.g., due to thermal expansion), so the detected temperature can optionally be taken into account. This allows for the easy implementation of different shifting concepts.

[0022] The present invention also relates to a control device for a manual transmission of a commercial vehicle, wherein the control device may include the sensor arrangement or at least be able to receive sensor signals from the sensor arrangement in order to control the manual transmission based on the detected sensor signals and to actuate actuators accordingly.

[0023] The embodiments of the present invention are better understood with the following detailed description and the accompanying drawings of the different embodiments, which, however, should not be understood as limiting the disclosure to the specific embodiments, but merely serve for explanation and understanding. Fig. Figure 1 shows a sensor arrangement according to an embodiment of the present invention. Fig. Figure 2 shows a sensing system for a tilting fork according to further embodiments.

[0024] Fig. Figure 1 shows a sensor arrangement according to an embodiment of the present invention. The sensor arrangement is suitable for angular detection of an actuating device 50, which is rotatably arranged in a holder 60. Fig. Figure 1 shows only a part of the actuating device 50, which can be, for example, a pivot axis of a shift fork.

[0025] The sensor arrangement comprises a first sensor element 110 and a second sensor element 120, wherein the first sensor element 110 is preferably coupled to the actuator 50 without backlash, so that when the actuator 50 is rotated, the first sensor element 110 also moves (relative to the holder 60). The second sensor element 120 is, for example, attached to the holder 60. A rotation of the actuator 50 relative to the holder 60 thus results in a relative movement between the first sensor element 110 and the second sensor element 120.

[0026] The first sensor element 110 can, for example, be fixedly attached to the actuator 50. Optionally, a coupling element 140 (e.g., a gearbox) can be formed between the first sensor element 110 and the actuator 50, so that the rotation angle of the actuator 50 is increased by the gearbox 140 and the first sensor element 110 therefore rotates at a higher angular velocity than the actuator 50 (any necessary support on the bracket 60 is shown in the Fig. (2 not shown). This allows the measurement accuracy to be increased.

[0027] Optionally, greater angle measurement accuracy can be achieved by increasing the radial extent of the first sensor element 110 (e.g., by using a larger disc, as in the Fig. (as shown in Figure 1). This does not increase the angular deflection, but the radial endpoints of the first sensor element 110 cover a greater distance during a rotation, and this greater distance is in turn easier to detect.

[0028] The first sensor element 110 can, for example, be a magnet, and the second sensor element 120 can, for example, detect the magnetic field generated by the first sensor element 110. For example, the first sensor element 110 can generate a magnetic field whose field lines are not rotationally symmetric about the axis of rotation of the actuator 50 (otherwise, the rotation would be barely detectable). A rotation of the actuator 50 thus causes a change in the magnetic field, which can be detected, for example, inductively, as a Lorentz force, or magnetoresistically by the second sensor element 120. Accordingly, the second sensor element 120 can, for example, be a coil, a Hall sensor, or a magnetoresistive sensor (e.g., GMR sensor, AMR sensor, TMR sensor, etc.).

[0029] The sensor arrangement can further include an evaluation unit 130, on which the second sensor element 120 can be attached. Based on the change in the magnetic field detected by the second sensor element, the evaluation unit 130 generates a sensor signal that indicates the angle of the actuating element 50.

[0030] Fig. Figure 2 shows a sensor for a rocker fork according to further embodiments of the present invention. In the Fig. In the embodiment shown in 2, the actuating means 50 is, by way of example, a shift fork of a gearbox, which is designed as a rocker fork.

[0031] The shift fork 50 (rocker fork) comprises a pivot bearing 62, a force point 55, and two fork ends, each equipped with a sliding block 57 for implementing a shifting operation. The sliding blocks 57 engage, for example, in a shift sleeve (not shown) and thus effect a linear movement perpendicular to the plane of the drawing to shift the transmission. The pivot bearing 62 defines an axis of rotation about which the shift fork 50 is rotatably held by the bracket 60. The force point 55 serves as the point on which a force can be applied to rotate the shift fork 50.

[0032] In the Fig. In the embodiment shown in Figure 2, the sensor arrangement comprises a housing 150 in which the second sensor element 120 and the evaluation circuit 130 are housed and together attached to the mounting 60. For example, the second sensor element 120 can be attached directly to the evaluation circuit 130 (e.g., a circuit board) or directly to the housing 150. However, this is not mandatory. The evaluation circuit 130 can be connected, for example, via a control line 132 and an optional connector 134 to a control unit (not shown in Figure 2). Fig. 2) Connectable. Sensor data from the second sensor element 120 can optionally also be transmitted to the control unit via a wireless connection or via a bus line.

[0033] In this embodiment, the first sensor element 110 is directly and rotationally fixedly connected to the switching fork 50, so that rotations of the switching fork 50 (relative to the holder 60) result in relative movements between the first sensor element 110 and the second sensor element 120. The first (or second) sensor element can in turn comprise a magnet (permanent magnet or electromagnet) which can be arranged such that rotation of the switching fork 50 relative to the holder 60 leads to a change in the magnetic field. The other sensor element can act as a magnetic sensor and detect the change in the magnetic field and generate a corresponding sensor signal.

[0034] For this magnetic detection, the second sensor element 120 can, for example, comprise a coil or other inductive means that is sensitive to a change in the magnetic field. Optionally, it is also possible for the second sensor element 120 to form a magnetoresistive sensor together with the first sensor element 110. Within the scope of the present invention, any sensor that detects a change in the resistance of an electric current as a result of a change in the external magnetic field can be used as a magnetoresistive sensor. However, the sensor arrangement can also detect the rotation of the switching fork (actuator) 50 based on the Hall effect (2D or 3D). The present invention is not limited to specific magnetic sensors. In further embodiments, the sensor arrangement can include an optical sensor to detect the rotation.For example, the first sensor element 110 can be a disc with slots that can be optically detected. Furthermore, inductive measuring principles can also be used.

[0035] In further embodiments, the first sensor element 110 and the second sensor element 120 can be interchanged, i.e., the second sensor element can also be attached directly or indirectly to the actuating device.

[0036] The advantages of the invention can be summarized as follows: For the implementation of a transmission control system, it is important to detect the position of the shift fork as accurately as possible. The closer the position sensor or a target (the first sensor element) can be attached to the shift fork, the less the measurement signal is affected by other influences such as deflection. Elasticities, etc., of the components involved in force transmission are distorted. Exemplary implementations lead to a significant improvement in control, as, for example, rotation can be directly detected.

[0037] Furthermore, additional functions can be implemented using the sensor arrangement according to the invention. For example, information about the fork positions can be determined over their service life. The sliding blocks 57, for example, are made of a bronze material, which can wear down over time. This wear can manifest itself as a change in the angular position (e.g., for an end position of a shifting operation). However, since sufficient linear movement of the exemplary shift sleeve, into which the sliding blocks 57 engage, is important for a successful shifting operation, this wear can be taken into account by the transmission control unit (not shown).

[0038] In a rocker fork, the shift fork pivots around an axis orthogonal to a corresponding input / output shaft axis. With precise measurement of the rocker fork's rotational position and corresponding calibration (conversion into a linear movement, e.g., of the shift sleeve), separate linear sensing of the actuator travel is unnecessary. Instead, the rocker fork's pivot angle can be directly measured and, using the calibration, converted into the corresponding linear movement that executes the shifting operation. This eliminates a large portion of the inaccuracies otherwise present in the measurement chain due to backlash and elasticity. Therefore, exemplary embodiments achieve significantly more precise position measurement of the shift fork through direct rotational angle measurement, contributing to an overall improvement in the controllability of the automated shifting and thus to increased drivetrain efficiency.

[0039] Aspects of embodiments of the present invention can also be summarized as follows: Exemplary embodiments relate to a position sensor, in particular an angle sensor, which is flanged to a bearing of a fork (actuating means 50). A permanent magnet, for example, which is rotationally fixed to the shaft of the fork, can be used as the target or as the element whose rotation is to be detected. The position sensor is a closed, encapsulated unit. The following operating principles, for example, can be used as sensor principles: magnetic (Hall, 3D-Hall, GMR, AMR), inductive (e.g., PLCD; permanent magnetic linear contactless displacement), optical (incremental).

[0040] Optionally, a gearbox can also be used to translate the angular range of the fork to a larger angular range for the target. This allows the goal of achieving a better angular resolution of the measuring system to be reached.

[0041] It is also possible to connect multiple sensors using a bus system. Output of internal temperature signals from the measuring element is also possible. Furthermore, a redundant design is available for safety-relevant applications (e.g., determining the fork position in the main gearbox). This can be achieved, for example, by providing a separate sensor arrangement for each of the two rotating mounts (opposite axes of rotation).

[0042] The angle signal can be directly converted into a corresponding distance or position signal of the shift fork along the corresponding input or output shaft axis by means of calibration.

[0043] Exemplary implementations allow for easy adaptation to different switching fork concepts through a universal interface concept. The mechanical and / or electrical sensor connection can be detached non-destructively.

[0044] The features of the invention disclosed in the description, claims and figures can be essential for the realization of the invention, both individually and in any combination. REFERENCE MARK LIST 50 actuators 55 Force pressure point 57 sliding stone 60 bracket 62 Rotary bearing 110, 120 first, second sensor element 130 evaluation circuit 132 Signal line 134 Plug connection 140 gearbox 150 cases

Claims

[1] Sensor arrangement for angle detection of a shift fork (50) of a manual transmission, wherein the shift fork (50) is rotatably arranged on a holder (60), characterized by : - a first sensor element (110) that can be coupled to the shift fork (50) in order to perform a movement relative to the holder (60) in response to a rotation of the shift fork (50); - a second sensor element (120) which can be fixed to the holder (60) in a rotationally fixed manner and which can be coupled to the first sensor element (110) in order to generate a sensor signal when the shift fork (50) is rotated and a resulting relative movement occurs between the first sensor element (110) and the second sensor element (120), which depends on the rotation of the shift fork (50) performed; - an evaluation circuit (130) on which the second sensor element (120) is mounted and which generates a signal based on the sensor signal that indicates an angle of the switching fork (50); and - a housing (150), wherein the second sensor element (120) and the evaluation circuit (130) together with the housing (150) can be fixed to the holder (60). [2] Sensor arrangement according to claim 1, characterized by , that the first sensor element (110) comprises a permanent magnet which generates a variable magnetic field by a rotation of the switching fork (50), and the second sensor element (120) is designed to generate the sensor signal in response to a change in the magnetic field. [3] Sensor arrangement according to one of the preceding claims, characterized by , that the first sensor element (110) and the second sensor element (120) are part of an inductive or magnetic sensor and in particular comprise a Hall sensor or a magnetoresistive sensor. [4] Sensor arrangement according to one of the preceding claims, characterized by , that the first sensor element (110) and the second sensor element (120) are optically coupled to each other. [5] Sensor arrangement according to one of the preceding claims, characterized by - a gearbox (140) that couples the first sensor element (110) with the shift fork (50) to translate a rotational angular range of the shift fork (50) into a larger angular range of the first sensor element (110) in order to enable a greater angular resolution. [6] Sensor arrangement according to any one of claims 1 to 4, characterized by , that the first sensor element (110) can be fixed to the switching fork (50) in a rotationally fixed manner. [7] Sensor arrangement according to one of the preceding claims, characterized by a temperature sensor to detect a temperature in order to perform a correction based on the detected temperature. [8] Sensor system that can be coupled to a control unit, characterized by - at least a first sensor arrangement according to one of claims 1 to 7 - at least a second sensor arrangement according to any one of claims 1 to 7; and - a bus designed to transmit data between at least one first sensor arrangement and at least one second sensor arrangement and the control unit. [9] Manual transmission, characterized by - a sensor arrangement according to any one of claims 1 to 7 or a sensor system according to claim 8; and - a control unit designed to control the shifting of the transmission and to evaluate sensor signals from the sensor array. [10] Manual transmission according to claim 9, characterized by , that - the control unit is designed to convert the sensor signal into a distance and thus determine the position of the shift fork in the gearbox. [11] Gearbox according to claim 9 or claim 10, characterized by - a further sensor designed to detect movement of the switching fork, so that the further sensor and the sensor arrangement are redundant in order to detect the rotation performed by the actuating means (50) in the event of failure of the further sensor or the sensor arrangement.

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