Method and apparatus for checking the engagement of the parking brake finger

Abstract

The present invention relates to a method for checking the engagement and disengagement of a parking brake finger (1 a) that serves to stop or unlock a transmission shaft under the control of an electrically rotatable selection plate (9), the electrically rotatable selection plate abutting against the transmission housing (3) at both ends of its travel, and between said ends, when the plate's drive motor stops applying torque to the plate, the selection plate stops in a first functionally engaged position (parked) or a second functionally disengaged position (unparked) with respect to the parking brake finger, characterized in that the angular displacement of the plate between its abutment positions is measured and incremented by a computer unit of the transmission to determine whether the parked or unparked functional position of the plate reached each time the drive motor stops corresponds to the command given to the motor by the transmission.

Description

Technical Field

[0001] The present invention relates to the control of a parking brake finger for any automatic, automated, or semi-automatic gearbox.

[0002] More precisely, the object of the present invention is a method for checking the engagement and disengagement of a parking brake finger that serves to stop or release a transmission shaft under the control of an electric rotary selection plate, which electric rotary selection plate abuts against the transmission casing at both ends of its stroke and, between both ends, when the motor of the plate stops applying torque to the plate, the plate stops at a first functional engagement position (parking) or a second functional disengagement position (non-parking) with respect to the parking brake finger. Yet another object of the present invention is an apparatus for carrying out the method.

Background Art

[0003] The immobilization of a vehicle by a parking brake is generally ensured by engaging a parking brake finger between the teeth of a gear integral with the transmission shaft of the vehicle, such as a gearbox or a differential shaft.

[0004] Publication FR2956180, which can be referred to, describes a parking brake mechanism with an operating lever outside the gearbox, the operating lever receiving, via a ball joint, the end of a control cable that is itself connected to a control selector for the driver, and the mechanism has a plurality of functional positions of the transmission, such as a parking position, a reverse position, a neutral position, a forward position, etc. The external lever is integral with an internal control shaft to which a control plate acting on the parking brake finger is attached.

[0005] The control plate has functional notch-type selection regions with alternating recesses and protrusions. Each recess corresponds to selecting one of a set of functional positions, including at least one engaged position and one disengaged position of the parking brake finger. The plate is fixed to the gearbox casing and cooperates with detent means capable of elastically holding the plate in each of the functional positions.

[0006] Currently, the position of the parking brake finger is detected by a position sensor or TRS (Transmission Range Sensor) that works in conjunction with the parking brake control element. If the volume available in the gearbox is reduced to accommodate the parking brake position sensor, other checking methods will be required. [Overview of the Initiative]

[0007] The objective of the present invention is to realize an internal function that checks the engagement of an electric parking brake without using a physical position sensor.

[0008] To this end, the present invention proposes that the angular displacement of the plate between contact positions is measured by the transmission computer unit and incremented to determine whether the parked or unparked position of the plate reached after each stop of the drive motor corresponds to a control command given to the plate drive motor by the transmission.

[0009] According to another feature of the present invention, when the vehicle is first used, - In order to determine the initial position of the parking brake from the magnitude of the displacement between the initial position of the parking brake and the contact position of the plate, the drive motor is operated in a first direction until the plate contacts the casing and stops, and then, - To return the plate to its initial position, the drive motor is operated in the opposite direction, - To store the initial position in the computer unit. Perform the learning phase which includes this.

[0010] The corresponding control device is: - A rotating plate, driven by a drive motor and mechanically connected to the parking brake finger, moves the parking brake finger between an engaged position between two teeth of the parking brake wheel and a disengaged position separated from the engaged position, - Mechanical means for holding the plate in a functional position relating to the engagement and disengagement of the parking brake, - A computer unit that can identify both positions on the plate and increase the angular displacement of the plate. It is equipped with.

[0011] The present invention will be better understood by referring to the attached drawings and reading the following description of non-limiting embodiments of the invention. [Brief explanation of the drawing]

[0012] [Figure 1] This is an overall diagram of the parking brake engagement mechanism. [Figure 2] This is a diagram showing the arrangement of the internal control plates of the mechanism within the gearbox casing. [Figure 3] This diagram shows the function of the mechanism in the control plate. [Modes for carrying out the invention]

[0013] The parking brake engagement mechanism in Figure 1 is located partially inside the gearbox 3. The parking brake engagement mechanism comprises an engagement tumbler 1 carrying a finger 1a, which engages between two teeth 2a of a parking brake wheel 2 fixed to a shaft (not shown) of the gearbox 1 in this configuration diagram. The mechanical connection between the external lever 4 and the tumbler 1 consists of a shaft 5 rotatably fixed to the lever 4, passing through the inside of the casing 3, and acting on a pusher 6 via a plurality of return elements 7a-7d. In the configuration diagram, the mechanism is in the parked position. The tumbler is pushed back toward the parking brake wheel by the pusher 6. In the neutral, reverse, and forward positions (not shown), the pusher 6 does not act on the tumbler 1. The tumbler is pushed back away from the parking brake wheel by a return spring 8. The external lever 4 in Figure 1 is actuated, for example, by a control cable (not shown) from a selector that can be used by the driver. In the case of an automatic or automated transmission, the control shaft 5 is electrified.

[0014] The proposed control device is shown in Figure 2, and in particular, - A rotating plate, which is driven by a drive motor and mechanically connected to the parking brake finger 1a (as shown in Figure 1), moves the parking brake finger 1a between an engaged position between two teeth 2a of the parking brake wheel 2 and a disengaged position separated from the engaged position, - Mechanical means (not shown in Figure 2) for holding the plate in a functional position related to the engagement and disengagement of the parking brake, - A computer unit (not shown) that can identify both positions of plate 9 and increase the angular displacement of plate 9. It is equipped with.

[0015] The selection plate 9 is rotated by the shaft 5. The selection plate has a functional area 9a having two recesses 9b, 9c separated by projections 9d. The two recesses correspond to the parked and unparked positions of the parking brake. The plate further comprises two end stoppers 9e, 9f, which abut against the support surfaces 3a, 3b of the transmission casing 3 at the end of the stroke.

[0016] When the rotating plate is displaced, the functional area 9a passes in front of an alignment or mechanical holding system fixed to the casing, such as a detent system (not shown). Recesses 9b and 9c determine functional selection positions, such as the P (parking) position and the non-parking position (allowing access to modes N, D, R, etc.). These recesses work in cooperation with the holding means to ensure the alignment of the plate 9 at each of its positions. Two side stoppers 9e and 9f that contact the casing limit the angular range of displacement.

[0017] When shaft 5 is motorized, the plate 9 reaching the stopper is detected, for example, by monitoring excessive electricity consumption by the drive motor attempting to continue rotating the shaft even though mechanical constraints are preventing it.

[0018] The mechanical means for holding the plate in a parked or non-parked functional position is, for example, a detent system, of which only the ball 11 of the detent system is shown in Figure 3. This figure diagrammatically shows the functional area 9a of the plate 9 with two support surfaces 3a, 3b, two recesses 9b, 9c, and projection 9d in Figure 2. The ball appears three times in contact with the stopper surface 3a of the casing and within the two recesses 9a, 9b, at positions A, B, and C, respectively.

[0019] The plate rotates in front of the ball 11 which moves substantially radially with respect to the plate. When the plate 9 rotates by the shaft 5, the functional area of the plate 9 passes by. The ball 11 enters its recess when the recess 9a or 9b of the plate passes by. When the torque of the drive motor vanishes, the plate is mechanically held in the parking or non-parking position. These two corresponding angular positions of the plate are the reference positions for the device to check the parking brake finger. These reference positions are transmitted to the engine or transmission computer (ECU) during parameterization (calibration or setting). Thus, the engagement of the parking position depends on the position of a mechanical component (in this case the ball 11) which does not move with respect to the recesses 9a, 9b of the plate, and these recesses pass in front of the mechanical component during the rotational displacement of the plate 9.

[0020] The method proposed by the invention makes it possible to check the engagement and disengagement of the parking brake finger of the transmission between two teeth of the wheel of the parking brake without a physical position sensor, the engagement and disengagement being in contact at both ends of the stroke with the transmission casing and between both ends, when the motor stops applying torque to the plate, the plate stops in the first functional engagement position (parking) or the second functional engagement position (non-parking) of the parking finger, under the control of an electrically rotatable control plate.

[0021] Thus, the invention makes it possible to dispense with a position sensor by using a counter or incremental sensor in the actuator.

[0022] At the first use of the vehicle, to know the position of the shaft - To identify the initial position of the parking brake from the magnitude of the displacement made between the initial position of the parking brake and the contact position of the plate, operate the drive motor in a first direction until the plate comes into contact with the casing and stops, and then - To return the plate to its initial position, operate the drive motor in the opposite direction - Store the initial position in the computer unit and A learning phase including is executed.

[0023] During this learning, the plate is displaced from the initial position to the side stopper of plate 9, and then the reference position is determined. As described above, the arrival at the stopper of plate 9 can be judged by overconsumption of the drive motor current. The shaft is then returned to the initial position by performing the same shaft displacement as before but in the opposite direction. In this way, the relative position of the shaft with respect to the stopper is known. The positions of the depressions (parked and non-parked) are specified, for example, during the setting or calibration of a computer (ECU).

[0024] The incremental sensor is used to quantify the angular displacement of the shaft and the plate, i.e., the width and direction of its angular displacement. From this information, no matter when the ball 11 is about to engage with one of the depressions 9b, 9c, the computer can determine which depression the ball has engaged with and thus whether the parked position has been engaged. The subsequent displacement of the plate is increased so that the parked or non-parked functional position of the plate can be identified with each subsequent stop of the drive motor.

[0025] Since the initial position has been determined by learning, with each subsequent displacement of the shaft 5, a new position of the shaft 5 is determined by the incremental sensor relative to its previous position. For example, if the shaft was at 50° from the stop position contacting the support surface 3a in the direction of the support surface 3a of the casing close to position P before displacing 10°, the position of the shaft is displaced to 40° from the support surface.

[0026] Considering that power to the computer is lost each time the vehicle is taken out of use, the shaft position needs to be periodically memorized so that it does not need to be relearned every time the vehicle is started. However, in the event of a sudden power loss, this information may also be lost. In that case, new learning must be performed by rotating the shaft in the direction in which the request was made (parked or not parked) until the plate hits the casing. For example, during reinitialization, if the plate is in the parked position (position B of ball 11 in the configuration diagram) and the driver requests the parked position, the drive motor is activated in the learning phase to rotate the shaft in the parking direction to the stopper surface 3a (displacement of ball 11 to the left in the configuration diagram until it reaches position A). The computer pays attention to the angle of movement between the parked position and the parking-side stopper 3a. From this, the computer deduces that the shaft was in the parked position, returns the gearbox plate to the same position, and memorizes that position.

[0027] The present invention has numerous advantages related to the omission of conventional TRS sensors, including the reliability of the novel method and the space savings resulting from this omission.

Claims

1. A method for checking the engagement and disengagement of a parking brake finger (1a) configured to selectively stop or release the movement of a vehicle's transmission shaft, Controlling an electrically operated rotary selector plate (9) that selectively contacts the transmission casing (3) at both ends of the stroke, wherein when the drive motor for the electrically operated rotary selector plate stops applying torque to the electrically operated rotary selector plate between the ends of the stroke, the electrically operated rotary selector plate selectively stops at a first functionally engaged position corresponding to the parking position of the parking brake finger or a second functionally disengaged position corresponding to the non-parking position of the parking brake finger, wherein the first functionally engaged position and the second functionally disengaged position are specified during the setting or calibration of the transmission computer, and controlling the electrically operated rotary selector plate (9). The transmission computer measures the angular displacement of the electrically rotary selector plate (9) between contact positions of the electrically rotary selector plate (9) with respect to the transmission casing, and by increasing the angular displacement using an incremental sensor, it is determined whether the first functional engagement position or the second functional disengagement position of the electrically rotary selector plate (9) reached after each stop of the drive motor corresponds to a control command given to the drive motor by the transmission computer. Includes, The system further includes performing a learning phase during the first use of the vehicle after a loss of power to the transmission computer, wherein the learning phase is performed In order to identify the initial position of the parking brake from the magnitude of the displacement between the initial position of the parking brake and the contact position of the electrically rotary selection plate (9) with respect to the transmission casing, the drive motor is operated in a first direction until the electrically rotary selection plate (9) contacts and stops against the transmission casing (3), and then, In order to return the electrically rotating selection plate (9) to the initial position, the drive motor is operated in the opposite direction, The initial position is stored in the transmission computer. Methods that include...

2. The method according to claim 1, further comprising increasing the subsequent displacement of the motor-rotating selector plate (9) to identify the first functional engagement position or the second functional disengagement position after each subsequent stop of the drive motor.

3. The method according to claim 1, further comprising storing the final position of the electrically rotary selection plate (9) in the event of a loss of power to the transmission computer in order to make the final position of the electric rotary selection plate (9) available for the next use of the parking brake.

4. The method according to claim 1, further comprising performing a new learning phase in the event of a sudden loss of power to the transmission computer.

5. The method according to claim 1, further comprising detecting the contact position of the electrically rotary selection plate (9) with respect to the transmission casing (3) by a sudden increase in voltage at the drive motor.

6. A control device for checking the engagement and disengagement of the parking brake finger (1a) of a transmission, A rotating plate (9) is operated by a drive motor and mechanically connected to the parking brake finger, and moves the parking brake finger between an engaged position between two teeth (2a) of the parking brake wheel (2) and a disengaged position separated from the engaged position, Mechanical means for holding the rotating plate (9) in a first functional position and a second functional position corresponding to the engagement position and the disengagement position of the parking brake, A computer configured to identify the first and second functional positions of the rotating plate and to increase the angular displacement of the rotating plate (9) using an incremental sensor, wherein the first and second functional positions are identified by moving the rotating plate (9) in the direction relative to each casing contact, and Equipped with, The first functional engagement position and the second functional disengagement position are specified during the setup or calibration of the computer. The computer performs a learning phase when the vehicle is used for the first time after a power loss to the computer, and the learning phase is performed In order to identify the initial position of the parking brake from the magnitude of the displacement between the initial position of the parking brake and the contact position of the rotating plate (9) with respect to the casing, the drive motor is operated in a first direction until the rotating plate (9) contacts the casing and stops, and then, In order to return the rotating plate (9) to the initial position, the drive motor is operated in the opposite direction, The initial position is stored in the computer. A control device, including a control device.

7. The apparatus according to claim 6, wherein the rotating plate (9) comprises a functional area (9a) having two recesses (9b, 9c) corresponding to the engagement position and the disengagement position of the parking brake, separated by a projection (9d).

8. The apparatus according to claim 7, wherein the rotating plate (9) has two end stoppers (9e, 9f) that abut against the transmission casing (3) at the end of the stroke.

9. The apparatus according to claim 6, wherein the mechanical means for holding the rotating plate (9) in the first functional position and the second functional position is a detent system.

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