JP2008075814A - Clutch device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic clutch device having a simple structure, capable of accurately detecting an abnormality of a clutch operating hydraulic circuit. <P>SOLUTION: In the case where oil leakage occurs in the clutch hydraulic circuit when the clutch is operated to be disengaged, there is a zone where an output of a motor is zero and a timing at which load is generated in a clutch actuator 1 is delayed. Also, when the clutch is operated to change from the disengaged state into an engaged state, there is a zone where the output of the motor is zero and negative load is generated in the clutch actuator 1 in the latter half of a stroke. The clutch device detects an abnormality of the hydraulic circuit based on whether or not an indication current value to the motor is within a predetermined range, by tentatively stroking an output rod according to a test pattern corresponding to the state of a vehicle or utilizing the stroke during changing gears. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a clutch device that is connected and disconnected by hydraulic pressure.

  In recent years, with regard to transmission, MT-based automated manual transmission (hereinafter referred to as “AMT”) has attracted attention due to its good fuel efficiency, and various companies are focusing on development. In particular, considering the trend in the European market, compact cars occupy a large proportion as AMT's listed models, and there is a demand for downsizing and space saving of clutch systems.

  For example, in Patent Document 1, a motor size in the clutch actuator is reduced by providing an assist mechanism (assist spring) that assists the rotating body in the clutch actuator that drives the output rod in a direction opposite to the load on the clutch side. An attempt is being made.

  Further, an automatic clutch of a type in which a master cylinder of a hydraulically operated clutch of Patent Document 2 which is advantageous in that a release fork can be omitted is promising.

JP 2004-35395 A Japanese Patent Laid-Open No. 11-230198 JP 2003-74684 A

  In the hydraulically operated clutch as described in Patent Document 2, it is considered that an abnormality such as oil leakage occurs in the hydraulic circuit between the master cylinder and the slave cylinder (hydraulic direct cylinder). When such an abnormality in the hydraulic circuit occurs, the pressure in the hydraulic circuit decreases, while the clutch actuator operates as instructed, and thus there is a problem that the abnormality cannot be detected by the stroke sensor of the clutch actuator.

  Further, as in Patent Document 3, in the case of the AMT, since a gear type transmission is used, a phenomenon that shift is difficult to occur due to mismatch of gear phase or mismatch of synchronization of the synchro mechanism occurs. In the case of the AMT system to be routed, the reason why the shift did not go well was due to the gear type transmission, or the clutch was kept in the engaged state due to the occurrence of an abnormality in the hydraulic circuit. There is also a problem that it is difficult to determine whether it is caused by the problem.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a clutch device that can accurately detect abnormality of the hydraulic circuit with a simple configuration.

  According to a first aspect of the present invention, a clutch disposed between an engine and a transmission, a clutch actuator that strokes an output rod by a motor, and an output end of the output rod are accommodated, and the output rod A clutch device comprising: a master cylinder that generates hydraulic pressure according to a stroke; and a slave cylinder that communicates with the master cylinder via a hydraulic circuit and controls connection / disconnection of a clutch according to the hydraulic pressure generated by the master cylinder. A clutch device comprising: an abnormality detecting means for detecting an abnormality of the hydraulic circuit based on whether or not a current value of the motor when the output rod is stroked is within a predetermined range. Provided.

  According to the present invention, it is possible to detect an abnormality of the clutch due to a malfunction of the hydraulic circuit without preparing a special sensor.

[First Embodiment]
Next, the best mode for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of an AMT vehicle system including a clutch failure detection device according to a first embodiment of the present invention. Referring to FIG. 1, a dry / single-plate friction clutch 40 is assembled to an output shaft (crankshaft) of the engine 30, and an automatic transmission 50 is connected via the friction clutch 40.

  The engine 30 includes a throttle valve for adjusting the amount of intake air, a throttle sensor for detecting the opening of the throttle valve (throttle opening), and a throttle actuator for opening and closing the throttle valve, and is controlled by the ECU 60. Is done.

  The friction clutch 40 includes a flywheel 41 fixed to the crankshaft of the engine 30, a clutch fading 43 fixed to both outer peripheral surfaces, and a clutch disk 42 that is spline connected to the input shaft of the automatic transmission 50 and rotates integrally. A pressure plate 44, which is a clutch assembly fixed to the flywheel 41, a diaphragm spring 45, a clutch cover 46, and a hydraulic direct cylinder (slave cylinder) 47 is configured.

  The friction clutch 40 changes the amount of rotation transmitted between the flywheel 41 and the clutch disk 42 by changing the pressure load of the clutch disk 42 against the flywheel 41 via the hydraulic direct cylinder 47, the diaphragm spring 45 and the pressure plate 44. It can be increased or decreased.

  The clutch actuator 1 rotates the output wheel (wheel) 5 by driving the DC electric motor 2 through a reduction gear 4 made of a worm gear formed on the output shaft of the DC electric motor (motor) 2. The master cylinder 7 is operated by moving the output rod 6 connected to the output wheel 5 by a pivot pin forward or backward (stroke, advance / retreat). An assist spring (assisting means) 3 is connected to the output wheel 5, and generates an assisting force (assisting force) in a direction (counterclockwise in FIG. 1) in which the friction clutch 40 is disengaged (disengaged). The output wheel 5 can be rotated with a smaller output (torque) of the DC electric motor 2.

  For example, in the initial state of FIG. 1, the pressure load is applied to the pressure plate 44 via the diaphragm spring 45 that generates the spring reaction force of the hydraulic direct cylinder 47 and the friction clutch 40 (force that biases the pressure plate 44 in the separating direction). Is generated, and a pressure-bonding load of the clutch disc 42 to the flywheel 41 is applied, so that rotation from the engine 30 side can be transmitted. On the other hand, when the hydraulic direct cylinder 47 is actuated, the diaphragm spring 45 is deformed, and the pressure-bonding load of the clutch disc 42 to the flywheel 41 is reduced.

  The automatic transmission 50 includes an input shaft and an output shaft. The input shaft is connected so as to be able to transmit power from the friction clutch 40 side, and the output shaft is connected so as to be able to transmit power to an axle (not shown). ing. Further, the automatic transmission 50 is provided with a shift actuator group for operating the shift stage switching, and a plurality of shift stages can be configured by the control of the ECU 60.

  The ECU 60 is mainly composed of a microcomputer (CPU), and includes a ROM that stores various programs and maps, a RAM that can read and write various data, an EEPROM that can hold data without a backup power source, and the like. In addition to the clutch stroke sensor 11, various sensors such as a throttle sensor, an accelerator sensor, an engine speed sensor, an input shaft speed sensor, an output speed sensor, a shift sensor, and a gear sensor are connected.

  The ECU 60 drives the clutch actuator 1 and the shift actuator group based on the input values from the various sensors, and performs shift control according to the vehicle driving state and the driver's driving intention by the program installed therein. The command current value to be supplied to control each actuator is calculated, and the command current value is transmitted to the clutch actuator 1 and the shift actuator group. The ECU 60 also functions as a clutch failure detection device, and strokes the clutch actuator 1 with an inspection pattern and timing determined in accordance with the vehicle state, and an instruction value that is a current value of the motor 2 during that time is feedback controlled. The indicated current value and the energized current value (actual current value) are monitored to determine whether or not the hydraulic circuit is abnormal (hereinafter, the energized current value will be described as an example).

  Hereinafter, the clutch failure detection operation executed by the ECU 60 will be described in detail with reference to FIG. FIG. 2 is a flowchart showing the flow of the clutch failure detection operation. Referring to FIG. 2, first, it is determined whether or not a detection start condition (described later in detail) determined according to the current vehicle state (running / stopping / shifting) is satisfied (step) S001).

  When it is determined in step S001 that the detection start condition is satisfied, the ECU 60 operates the clutch actuator 1 with an inspection pattern (described later in detail) corresponding to the current vehicle state (step S002).

  Subsequently, the ECU 60 compares the command current value to the motor 2 corresponding to the load of the clutch actuator with a predetermined threshold value (step S003).

  Here, when the command current value to the clutch actuator 1 is equal to or less than a predetermined lower limit threshold value or equal to or greater than a predetermined upper limit threshold value, the ECU 60 determines that the failure due to the hydraulic circuit has occurred in the friction clutch 40 (abnormal). Judgment is made and a fail-safe operation corresponding to the vehicle state is executed (step S005).

  The above operation is continued until a predetermined detection end condition is established such that the inspection by the inspection pattern is completed successfully or the inspection cannot be continued by the operation of the driver.

  Next, the detection principle of the clutch failure based on the command current value to the clutch actuator 1 will be described. FIG. 3 is a diagram showing the relationship between the clutch cover load (spring reaction force of the diaphragm spring) A during normal operation, the assist mechanism assisting force B, and the motor work C that is the difference between them. When there is no abnormality in the hydraulic circuit of the friction clutch 40, the balance between the load necessary for clutch operation (clutch cover load A) and the assist mechanism (assist mechanism assisting force B) is kept moderate, and the motor 2 The command current value (motor work C) is within a certain range.

  On the other hand, FIG. 4 shows the relationship between the clutch cover load A ′ (spring reaction force of the friction clutch 40) when the oil leaks in the hydraulic circuit, the assist mechanism assisting force B, and the motor work C that is the difference between them. FIG. When oil leakage occurs in the hydraulic circuit, the pressure in the hydraulic circuit decreases, so the clutch cover load line (the spring reaction force of the diaphragm spring) viewed from the clutch actuator 1 causes the clutch disengagement as shown by A 'in FIG. Shift to the side, and a region (play region) where the clutch cover reaction force cannot be obtained occurs in the low stroke region.

  In this state, if the clutch is operated to the disengagement side, the motor work is 0 in the section where the assist mechanism assisting force B exceeds the clutch cover load A ′ (point O → point a in FIG. 4). Only when the clutch cover load A ′ exceeds the assist mechanism assisting force B, a load is generated in the clutch actuator 1, and the clutch is brought into a completely disconnected state (point a → point b in FIG. 4). In this region, the assist mechanism assisting force B is also small, and depending on the specifications of the motor 2, it may be difficult to perform the clutch disengagement operation. However, the following description will be made assuming that the clutch disengagement operation is possible.

  From the clutch disengaged state, this time, when the clutch is operated to the engagement side, the motor work in the section where the clutch cover load A ′ exceeds the assist mechanism assisting force B (point c → point d in FIG. 4) Even if 0 is acceptable, when the clutch cover load A ′ reaches a section where the assist mechanism assisting force B is exceeded (point d → point O in FIG. 4), a negative load is generated in the clutch actuator 1.

  As described above, when oil leakage occurs in the hydraulic circuit of the clutch 40, when the clutch actuator 1 is stroked, the motor instruction current value becomes extremely low or high, or a negative load is generated. It is possible to detect a failure by monitoring the motor command current value.

  Next, a failure detection operation (inspection pattern) for each vehicle state will be specifically described with reference to FIG.

[(A) Running]
The clutch failure detection operation while the vehicle is running is executed at regular intervals (n-hour intervals) when the clutch stroke is at the complete engagement point and the stroke can be moved to the stroke amount disconnection side necessary for detection.

  The stroke section is set as a disconnection stroke MAX on the engagement side of a certain amount from the engine torque so that the clutch torque is less than the engine torque and does not enter a half-clutch state at the disconnection stroke.

  By monitoring the motor command current value at this time (the smoothing process is performed as necessary), it is possible to detect a clutch failure. For example, when the motor command current value is greatly deviated from the normal motor work C line in FIG. 3 as shown in the section of point O → point a, point d → point O in FIG. If an extremely low value or a negative value is taken, oil leakage is suspected. Note that when a failure is detected during traveling, fail-safe control is performed such that the driver is notified of the abnormality while maintaining the current gear position.

  On the other hand, when the clutch stroke returns to the detection start position and no abnormality is detected, the process ends normally. If the engine torque changes during clutch failure detection, and it becomes impossible to secure a determinable stroke amount, a shift request is entered, or the vehicle enters a stop state, detection ends (stops). It becomes.

  In addition to the case where the clutch stroke is at the complete joint point, the clutch stroke is an emergency disconnection torque point (in the relationship between the stroke and the torque, the transmission torque capacity value due to the compression load of the clutch is the torque generated in the drive train including the engine. The point where the safety factor becomes equal to the torque value set to a relatively small value, and when the clutch stroke is made to the clutch disengagement side from this point, the clutch starts to slip after a relatively short time) If the required clutch stroke can be secured, the clutch failure detection operation can be performed in the same manner.

[(B) Stopping]
The clutch failure detection operation when the vehicle is in a stationary state is constant when the clutch stroke is at a predetermined stroke position (eg, disengaged MAX position) and the stroke can be moved to the stroke amount joint side required for detection. It is executed at intervals (n hour interval, engine start, etc.).

  In a stroke section, when a stroke is made to the joining side, a certain amount of joining side is set as a joining stroke MAX from a predetermined breaking stroke position (eg, breaking MAX position) within a range where clutch torque is not generated.

  By monitoring the motor command current value at this time (the smoothing process is performed as necessary), it is possible to detect a clutch failure. For example, when the motor command current value is greatly deviated from the normal motor work C line in FIG. 3 as shown in the section of point a → b, point c → point d in FIG. Oil leak is suspected. When a failure is detected while the vehicle is stopped, fail-safe control is performed such as transition (maintenance) to the neutral stage and engine stop when the shift to the neutral stage cannot be performed.

  On the other hand, when the clutch stroke returns to the detection start position and no abnormality is detected, the process ends normally. Further, when a shift request is made by operating the shift lever during the clutch failure detection operation, or when the vehicle starts and transitions to the running state, the detection ends (stops).

[(C) During shifting]
It is also possible to perform a clutch failure detection operation using the clutch stroke during the shifting of the vehicle.

  In this case as well, during the traveling (A) and (B) when the vehicle is stopped, the failure of the clutch can be detected by monitoring the motor command current value (the smoothing process is performed if necessary). it can. The section to be monitored does not have to be the entire section. For example, only the section in which the command current value greatly deviates when oil leakage occurs in the hydraulic circuit as in (A) traveling may be monitored.

  If an abnormality is detected during the shift, the shift stage of the automatic transmission 50 is not started (before the gear is released in the automatic transmission 50) or after the shift stage is completed (the gear is engaged in the automatic transmission 50). If (after), maintenance of the shift stage before the start of shifting, maintenance of the shift stage after completion of shifting, and notification of abnormality to the driver are performed. Further, if the clutch is disengaged and the gear position of the automatic transmission 50 is being switched (after the gear in the automatic transmission 50 is disengaged and before the next gear meshing gear is engaged), the automatic transmission The operation of notifying the driver of the abnormality, such as the transition of the gear stage of the machine 50 to the neutral stage or the engine stop, is performed. Furthermore, if the driver steps on the brake pedal or if an abnormality is detected when the vehicle is traveling at a low speed, the vehicle will go to the neutral stage to prevent the vehicle from moving forward regardless of the driver's intention. Change, engine stop and abnormality notification.

  On the other hand, if no abnormality is detected during the shift process, the process ends normally. If the shift itself is stopped, the detection is naturally ended (stopped).

  In addition, when the vehicle shifts as in Patent Document 3, the ECU 60 fails to change gears in the automatic transmission 50 (after the gear in the automatic transmission 50 is disengaged and the next gear meshing gear). If the engagement is not successful, the output rod 6 is stroked for the purpose of connecting / disconnecting the clutch or within a predetermined stroke range, and at the same time, whether the energization current value of the motor 2 is within the predetermined range. Detect whether or not. Thereby, in order to improve the normal gear engagement (if the gear in the automatic transmission 50 does not engage well at the time of shifting, the engagement in the gear is improved by rotating the gear in the automatic transmission 50). An abnormality in the hydraulic circuit can be detected during the re-stroke operation of the clutch that is performed. Therefore, it is possible to quickly detect the shift abnormality caused by the abnormality of the hydraulic circuit, and it is possible to avoid the repeated re-stroke operation of the clutch.

  As described above, it is possible to detect a clutch failure due to a malfunction of the hydraulic circuit based on the motor command current value. In the above-described embodiment, an example in which the assist spring (assisting means) 3 is built in the clutch actuator 1 has been described. However, a case without the assist spring (assisting means) 3 is also illustrated in FIG. A failure in the hydraulic circuit of the clutch can be detected based on whether or not the load (indicated current value) corresponds to the clutch cover load A.

[Second Embodiment]
Next, a second embodiment of the present invention in which a hydraulic switch is added to the first embodiment will be described. FIG. 6 is a schematic configuration diagram of the second embodiment of the present invention. The difference from the first embodiment is that a hydraulic switch 12 is arranged on a hydraulic circuit.

  FIG. 7 is a flowchart showing the flow of the clutch failure detection operation in the present embodiment. The difference from the first embodiment is that the instruction current value in step S103 (corresponding to step S003 in FIG. 2) Even if no abnormality is detected by comparison with the threshold value, if the pressure switch is operating in a region where it does not normally operate (see the double arrow in the center of FIG. 8), a failure caused by the hydraulic circuit occurs in the clutch 40. This is a point where it is determined that a fail-safe operation corresponding to the vehicle state is executed (step S105).

  According to the present embodiment, an abnormality in the clutch hydraulic circuit is reliably detected not only when the abnormality is not detected by the clutch failure detection operation but also when the clutch failure detection operation due to the vehicle state transition is stopped. can do.

  Further, in the above-described embodiment, it has been described that it is determined that a failure has occurred if either the comparison between the command current value and the threshold value or the state of the pressure switch indicates an abnormality. Depending on the specifications of the pressure switch, it can be set so that a failure is determined only when both the comparison between the command current value and the threshold value and the state of the pressure switch indicate abnormality.

  The preferred embodiment of the present invention has been described above. However, the technical scope of the present invention is not limited to the above-described embodiment, and the clutch actuator is operated with an inspection pattern according to the vehicle state. It goes without saying that various modifications and replacements can be made without departing from the gist of the present invention in which a failure of the hydraulic circuit is detected based on whether or not the indicated current value is within a predetermined range. Absent. For example, if the correspondence between the clutch stroke and the command current value in the normal state is held on a map, etc., the command current value at any clutch stroke will be out of a certain range that anticipates wear of the clutch cover, etc. It can also be determined.

1 is a schematic configuration diagram of an AMT vehicle system including a clutch failure detection device according to a first embodiment of the present invention. It is a flowchart showing the flow of the operation | movement (clutch failure detection operation | movement) of the 1st Embodiment of this invention. FIG. 2 is a diagram illustrating a relationship among a normal clutch cover load A, an assist mechanism assisting force B, and a motor work C in the configuration of FIG. 1. FIG. 2 is a diagram showing a relationship among a clutch cover load A ′, an assist mechanism assisting force B, and a motor work C when oil leaks in the configuration of FIG. 1. It is a figure for demonstrating the failure detection operation (inspection pattern) for every vehicle state (Driving / stopping / shifting). It is a figure showing the structure of the 2nd Embodiment of this invention. It is a flowchart showing the flow of the operation | movement (clutch failure detection operation | movement) of the 2nd Embodiment of this invention. FIG. 4 is a diagram in which a pressure switch operation region (double-arrow line) is added.

Explanation of symbols

1 Clutch actuator 2 (DC motor) motor 3 Assist spring 4 Reducer 5 Output wheel (rotating member)
6 Output rod 7 Master cylinder 8 Hydraulic source (oil pump)
11 Clutch stroke sensor 12 Hydraulic switch 30 Engine 40 Friction clutch 41 Flywheel 42 Clutch disc 43 Clutch fading 44 Pressure plate 45 Diaphragm spring 46 Clutch cover 47 Hydraulic direct cylinder (slave cylinder)
50 Automatic transmission 60 ECU (Electronic Control Unit)

Claims (7)

A clutch disposed between the engine and the transmission;
A clutch actuator that strokes an output rod by a motor; a master cylinder that accommodates an output end of the output rod; and that generates hydraulic pressure according to the stroke of the output rod; and communicates with the master cylinder via a hydraulic circuit; A slave cylinder that controls connection / disconnection of the clutch according to the hydraulic pressure generated by the master cylinder,
An abnormality detecting means for detecting an abnormality of the hydraulic circuit depending on whether or not the current value of the motor when the output rod is stroked is within a predetermined range;
A clutch device characterized by the above. The abnormality detection means executes an inspection pattern in which the output rod is stroked within a range in which the clutch engagement / disengagement state does not change during traveling of the vehicle;
The clutch device according to claim 1. The abnormality detection means executes an inspection pattern in which the output rod is stroked within a range in which the connection / disconnection state of the clutch is not switched while the vehicle is stopped.
The clutch device according to claim 1 or 2. The abnormality detecting means detects an abnormality of the hydraulic circuit using a stroke of the output rod during a shift of the vehicle;
The clutch device according to any one of claims 1 to 3. Furthermore, a stroke sensor for measuring the stroke amount of the output rod is provided,
Detecting an abnormality of the hydraulic circuit by a correspondence relationship between a stroke amount of the output rod and a current value to the motor;
The clutch device according to any one of claims 1 to 4, wherein: The abnormality detecting means further detects an abnormality of the hydraulic circuit using a state of a pressure switch provided in the hydraulic circuit between the master cylinder and the slave cylinder;
The clutch device according to any one of claims 1 to 5. The abnormality detection means strokes the output rod when the vehicle fails to change gears in the transmission when shifting.
At the same time, detecting whether the current value of the motor is within a predetermined range,
The clutch device according to any one of claims 1 to 6.

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