FR2842765A1 - Clutch pedal lock for motor vehicle has motor to oppose movement of clutch pedal when no actuating force is detected - Google Patents

Abstract

The manual transmission motor vehicle has a lock for the clutch pedal and a control to operate the lock when no indication is detected of clutch operation force. The lock can exert a sufficient resistance force to the pedal force exerted by a users foot. The lock can have a motor which progressively reduces its resistance force when released.

Description

IN A VEHICLE, DEVICE FOR CONTROLLING A PEDAL

CLUTCH THAT CAN BE BLOCKED

  The invention relates to a device for controlling a lockable clutch pedal. In a vehicle, the locked pedal can be used by

example of footrest.

  A clutch for a motor vehicle is generally intended to control the transmission of a torque from the crankshaft of a heat engine to the wheels of the vehicle via a gearbox. The clutch has a disengaged position in which no torque is transmitted, and a clutched position in which all the torque supplied by the

  engine is transmitted to the gearbox.

  The clutch can be controlled by a clutch pedal located in the passenger compartment of the vehicle and actuated at the foot by a driver. The stroke of the clutch pedal is approximately inversely proportional to the effort required to actuate it. The clutch pedal is positioned in the passenger compartment according to ergonomic zones defined for large, medium or small populations intended for the vehicle. The clutch pedal is used at start-up or when a gearbox change is envisaged, that is to say for very short moments compared to the duration of a journey made.

by the driver.

  There is also a footrest in the passenger compartment of a vehicle providing the driver with a comfortable place to put his foot when he is not using the clutch pedal. By using the footrest, the driver avoids damaging the clutch by leaving his foot on the clutch pedal. The location and shape of the footrest in the passenger compartment is conditioned in particular by the shape and volume of the wheel arch. The location of the footrest is also chosen so that the driver can comfortably pass from the

clutch pedal to the footrest.

  The compromise between the ergonomics of the clutch pedal, the ergonomics of the footrest in the passenger compartment of the vehicle, and the habitability of the vehicle becomes more and more difficult to find, in particular because the wheel arches become more and more intrusive in the cabin

of the vehicle.

  An objective of the invention is to further increase the comfort of the driver. Another goal

  is to increase the habitability of the vehicle.

  These objectives are achieved with a device for controlling a clutch control pedal associated with a manual gearbox. According to the invention, the control device comprises a means for blocking the pedal, and a control means for activating the blocking means when no indication is detected except a request for

the clutch will take place.

  A clutch pedal controlled by a control device according to the invention can then, when locked, be used as a footrest. The comfort of the user is thus considerably improved since he no longer needs to move his foot to go from the clutch pedal to the footrest. The habitability of the vehicle is also improved: in fact, the usual footrest can be deleted and the position and the stroke of the clutch pedal can be chosen without taking into account the

position of the footrest.

  The control device of the invention can be used with any type of clutch pedal. It can for example be used to control a pedal mechanically associated with a conventional clutch, association made for example by a cable. The device according to the invention is however particularly advantageous for controlling a robotic clutch receiving an electronic command associated with a movement of the pedal. In this case, the control device will advantageously be associated with the force feeling device associated with such

robotic clutches.

  The locking means, when active, produces a resistant force dimensioned to resist the force produced by a driver's foot placed on the pedal. In one example, the blocking means may for example be an electric motor whose torque is variable and depends in particular on the resistant force to be produced. In another example, the blocking means can be a spring, the stiffness of which is variable and a function of the resistant force to be produced. The blocking means can be suddenly deactivated by the control means, by eliminating the resistant force provided by the blocking means on the clutch pedal. However, preferably, the blocking means is deactivated by progressively decreasing the resistance force applied by the

locking means.

  The control means comprises means for detecting an indication that a solicitation of

the clutch will take place.

  The control means may in particular comprise means for detecting a speed of an engine of the vehicle associated with the gearbox. The engine speed detection means is for example able to deactivate the blocking means when the engine speed varies rapidly, or when the engine speed is constant equal to zero, or when the engine speed

  is less than an engine idle speed.

  The control means can also comprise means for detecting a will of a driver to request the clutch, and deactivating the blocking means when such a will is detected. The will detector includes, for example, a presence detector of a driver's hand on a gear lever or a button associated with the control of the gearbox, the said button being for example placed in the vicinity of the steering wheel or the board.

of the vehicle.

  The invention will be better understood and other characteristics and advantages will become apparent from the

  reading of the description which follows, of an example

  for implementing a device for controlling a

  clutch pedal according to the invention. The description

  is to be read in relation to the appended drawings in which: FIG. 1 is a diagram showing the evolution of the force to be supplied on the clutch pedal to disengage, as a function of the displacement of the pedal, and FIG. 2 is a diagram detailing the conditions under which the clutch pedal can

be blocked.

  Figure 1 shows, in solid lines, the usual evolution of the pedal force as a function of the movement of the clutch pedal during a clutch release. Pedal effort is the effort the driver must make to move the clutch pedal. The movement of the pedal indicates the position of the pedal in relation to a

DO rest position.

  Initially, the pedal being in the rest position, the effort with the Emin pedal is fairly low and then gradually increases when the pedal moves to a high point known by the expression "bump effort". The force then decreases slightly to a low point known by the expression "force in the trough", then it increases again until a breakpoint Emax known by the expression "force at the stop". The difference in effort to provide between the point of effort at the hump and the point of effort at the bottom is called saddle. The control device of the invention associated with the usual clutch control device modifies the curve of FIG. 1 in the following manner. When the pedal is locked in the rest position, then the effort at the pedal when the displacement of the pedal is zero (point DO) is significant, for example equal to the effort at the stop EMax. In all cases, the effort is chosen to be sufficient for the pedal to withstand the effort exerted by the weight of the driver's foot. On the contrary, when the pedal is released, the force curve of the pedal as a function of the displacement of the

  pedal is similar to that known.

  According to a first embodiment, the control means suddenly deactivates the blocking means, so that the pedal is suddenly released: the force on the pedal then suddenly changes from its maximum value Emax to its minimum value Emin. This embodiment is easy to carry out, using an all-or-nothing or open / closed device. However, it is not very comfortable for the driver, who risks, at an unwanted instant, feeling his foot abruptly depress the clutch pedal when the locking means are deactivated. According to another embodiment, the control means deactivates the blocking means by progressively reducing the resistance force applied by the blocking means by the pedal. The effort on the pedal thus slowly decreases until it returns to its usual value. This translates concretely on the

  Figure 1 by the dotted curve between DO and Dl.

  This embodiment is fairly simple to implement using as a locking means an electric motor with variable torque or a spring with variable stiffness. This embodiment is also comfortable for the user because it does not

  do not feel a sudden rupture of effort.

  In one example, the control means of the invention activates or deactivates the blocking means according to the diagram in FIG. 2. The control means here comprises means for detecting the presence of a hand of the driver on the lever.

  speed, and engine speed detection means.

  The locking means is deactivated and the clutch pedal is released when the driver's hand is detected on the gear lever. It is assumed that by placing his hand on the gear lever, the driver expresses his wish to change the gearbox ratio and

is therefore about to disengage.

  The locking means is deactivated and the clutch pedal is released when the engine speed R is lower than the engine idling speed Rraisi, that is to say when the engine is at the limit of stalling. It is estimated in this case that a

  declutching is necessary and will be carried out.

  The locking means is also deactivated and the clutch pedal released when the engine speed R is greater than the idle speed Rralenti and varies greatly, which results in a significant slope of the curve variation of the engine speed as a function of time ( AR / AT). This condition is fulfilled, for example, when the driver accelerates or brakes strongly before changing gearbox, or when an impact has occurred and the

vehicle decelerates sharply.

  In all other cases, the locking means is active and the clutch pedal is locked in the rest position, so that it can be used as a footrest by the driver. For example, when the engine speed is higher than the idle speed and when it varies little, it is estimated that the vehicle has reached a cruising speed and that the driver does not wish to disengage, the pedal can then be blocked. In the same way, when the driver's hand is not detected on the gear lever, it is estimated that the driver does not wish to disengage, the pedal can therefore be kept blocked.

Claims (10)

  1. In a vehicle, device for controlling a clutch control pedal associated with a manual gearbox, characterized in that it comprises means for blocking the pedal, and control means for activating the means blocking when no indication is detected that a request for the clutch will take place.   2. Device according to claim 1, characterized in that, when active, the blocking means is capable of imposing on the pedal a resistant force sufficient to withstand a force produced by a foot placed on the clutch pedal.   3. Device according to claim 2, characterized in that the control means is able to deactivate the blocking means by progressively reducing the resistance force applied by the blocking means on the clutch pedal. 4. Device according to claim 2 or 3, characterized in that the locking means comprises an electric motor of which a torque is representative of the resistance force applied by the electric motor on the clutch pedal, the said torque being able to be varied by the means of piloting.   5. Device according to claim 2 or 3, characterized in that the blocking means comprises a spring whose stiffness is representative of the resistant force applied by the spring on the clutch pedal, said stiffness can be varied by the piloting means.   6. Device according to claim 1 to 5, characterized in that the control means comprises means for detecting a speed of an engine of the vehicle associated with the gearbox.   7. Device according to claim 6, characterized in that the engine speed detection means is capable of deactivating the blocking means when the engine speed varies rapidly.   8. Device according to claim 6, characterized in that the engine speed detection means is capable of deactivating the blocking means when the engine speed is constant equal to zero.   9. Device according to claim 6, characterized in that the engine speed detection means is able to deactivate the blocking means when the engine speed   is less than an engine idle speed.   10. Device according to one of claims 1 to 9,   characterized in that the control means also comprises means for detecting a will of a driver to request the clutch, and deactivating the   blocking means when such a will is detected.   he. Device according to claim 10, characterized in that the will detector comprises a detector of the presence of a driver's hand on a gear lever or a button associated with the control of the gearbox.