FR2783481A1 - Automobile motorized parking brake with possibility of manual operation has drive motor and rack-and-pinion system - Google Patents

Abstract

The motorized parking brake has a brake unit (U2) linked to the vehicle wheels and an operating unit (U1) which includes a motorized actuation device (S1), and manual mechanism for brake operation. The units (U1,U2) are connected to each other via a transmission rod (1). The motorized actuator (S1) and the manual actuator (S2) are mechanically coupled in parallel with the transmission rod (1) so as to act on the latter independently of each other. The transmission rod is fixed to a toothed wheel (11) which meshes with first and second pawls (10,13) which form the driving force for the motorized unit (S1) and the manual unit (S2).

Description

The present invention relates to a brake

  motorized parking for a motor vehicle.

  Motorized parking brake regulations require the driver of the vehicle to be able to manually apply the brake in all circumstances, in order to be able to remedy an emergency situation or a failure preventing the motorized brake mechanism from operating. Several solutions in this direction have already been proposed

in the prior art.

  Thus in particular in documents EP 0 473 979 and DE 42 28 381, a particular device makes it possible to manually switch from motorized control to manual control. This proposition is unsatisfactory since it requires a prior switching operation of the driver before the parking brake can be manually applied. This complicates the handling of the brake and lengthens the operation in the event of emergency braking. In addition, the parking braking systems described in these documents are relatively complex and require a conventional braking lever disposed at

  the usual place between the front seats of the vehicle.

  This is also the case in another previous proposal described in DE 197 05 105 and which consists in providing a motorized assistance control which comes to provide an additional driving force supplementing the action exerted manually by the usual brake lever. The motorized assistance is triggered by the driver of the vehicle by means of a switch mounted on the manual lever and it makes the latter move when the brake is applied in the same way as if only manual action was exerted. The assistance driving force is provided by a motor driving a rod which is clutchable and disengageable on the member transmitting the manual braking force of the lever to the cable leading to the parking brake drums. For this, there is an additional electromagnetic actuator energized at the same time as the

  electric motor providing braking assistance.

  When the brake is actuated only manually, the rod disengages by gravity from the

transmission leading to the drums.

  In this prior arrangement, the usual lever remains essential. Furthermore, the rod cannot be positively disengaged from the transmission member, which leaves uncertainty as to the correct execution of the clutch in the event of an electrical system failure. Finally, the release of the brake cannot be done with the assistance of the electric motor but remains an operation

fully manual.

  The object of the invention is to provide a motorized parking brake requiring no particular switching maneuver prior to a manual braking action and making it possible to eliminate the manual braking lever, the assembly being of a simple construction and meeting the regulations. in force in this area. The invention therefore relates to a motorized parking brake for a motor vehicle comprising a braking unit associated with the wheels of the vehicle and an actuation unit comprising motorized actuation means and manual means for actuating the brake, these units being connected to each other via a movement transmission link, characterized in that said motorized actuation means and said manual actuation means are mechanically coupled in parallel to said transmission transmission link so that we can act on it

independently of each other.

  Thanks to these features, no switching is necessary to switch from motorized to manual operating mode. In addition, the arrangement according to the invention makes it possible to choose for manual control means other than a lever placed between the front seats of the vehicle. Finally, its construction is

  simple and perfectly reliable.

  According to other characteristics of the invention: - said transmission link is integral with a toothed wheel meshing with first and second racks movable in longitudinal translation, said racks respectively forming the motor outputs of said motorized actuation means and said means manual operation; said motorized actuating means comprise a drive motor, preferably electric, coupled to said first rack so as to be able to cause its longitudinal translation, as well as an adjustment loop making it possible to control the drive motor in both directions; said manual actuation means comprise a manual traction cable wound on a rotary drum coupled to said second rack by means of a disengageable coupling mechanism, to allow the longitudinal translation of this second rack by unwinding of said traction cable manual said drum; the parking brake being of the type comprising jaws associated with the vehicle wheels and means for returning these jaws to the released position of the brake, said drum is mounted on a rotary shaft to which is coupled a latching assembly with release by rapid release, the blocking action of which is opposed to the action of said jaw return means; said disengageable coupling means comprise a sleeve which is mounted movable in translation and in rotation and whose internal bore is grooved in first and second zones and devoid of grooves in a third intermediate zone between the first and second zones, and in that toothed wheels mesh with these grooves and are respectively coupled to said second rack and to said drum, said sleeve being further coupled in translation to said drum to allow the sliding of one of said toothed wheels from said first or second zone towards said third zone; - Said manual traction cable is sheathed and ends up on the dashboard of the vehicle; - said motorized and manual actuation means are housed in a common casing placed outside

the passenger compartment of the vehicle.

  Other characteristics and advantages of the invention

  will appear during the description which follows,

  given solely by way of example and made with reference to the accompanying drawings in which: - Figure 1 is a partial schematic view of the motorized actuation means of a parking brake according to the invention, the brake being released; - Figure 2 is a partial view similar to that of Figure 1, the parking brake being applied by a motorized action; - Figure 3 is a partial view similar to that of Figures 1 and 2, the brake being applied by manual action; - Figure 4 is a schematic view, partially in section of the manual actuation means of a parking brake according to the invention, showing the transmission ensuring manual actuation before a manual braking action; - Figure 5 is a view similar to that of Figure 4, showing the manual actuation means while their constituent parts are in their intermediate position during a manual braking action; - Figure 6 is a view similar to those of Figures 4 and 5, showing yet another phase of operation of the manual actuation means during manual tightening; and - Figures 7A to 7E are schematic detailed views of a cam and ratchet snap forming part of the manual actuation means shown on

Figures 4 to 6.

  In general, the figures represent only the essential parts for understanding the invention, the construction details the scope of

  the person skilled in the art is not represented.

  According to the preferred embodiment of the invention shown by way of example in the figures, the parking brake essentially comprises two functional units which are on the one hand an actuation unit Ul divided itself roughly into a section motorized actuation S1 (Figures 1 to 3) and a manual actuation section S2 (Figures 4 to 6), and on the other hand a brake unit U2 proper formed by the wheel brakes symbolized in the rectangle U2 on Figure 1. The units Ul and U2 are functionally connected to each other by a transmission link which, in the present example, is formed by a traction cable 1. The wheel brakes forming the unit U2 can be of any known type actuated by a movement transmission link such as a cable. They are not

therefore not described in detail here.

  The unit U1 is housed in a casing 2 comprising a first chamber 2a essentially housing the section Si and having roughly the shape of a flat box. The section S2 of the unit U2 is housed in a second chamber 2b of the casing 2 roughly in the form of an elongated rectangular parallelepiped whose longitudinal dimension is perpendicular to the large faces of the chamber 2a of the casing 2. The cable 1 passes through an opening 3 practiced

  in one of the side walls of the chamber 2a.

  The motorized actuation section Si comprises an electric motor 4 mounted outside against the wall of the chamber 2a. This motor 4 is connected to a circuit 5 for adjusting the position of the parking brake (shown for simplicity only in FIG. 1) which comprises a control button 6 on which the driver of the vehicle can act. The adjustment circuit 5 can function as a loop for adjusting the clamping force of the parking brake. This adjustment loop can use the signal from button 6 as a set signal for a clamping force, and as an actual signal for a clamping force, a signal supplied by a sensor 7 associated with the shoes of the parking brake. The adjustment loop 5 can apply the on-board electrical voltage from a terminal 8 to the drive motor 4 to rotate it in the direction of application of the brake (traction on cable 1) and in the

  opposite direction (loosening of this cable 1).

  The button 6 can be provided in the passenger compartment of the vehicle in a favorable location from a point of view

  ergonomic, for example on the dashboard.

  Of course, the motor 4 can also be other than electric with the necessary adaptations, for example at the level of the adjustment loop 5, which are at the

scope of the specialist.

  The motor 4 is coupled to an endless screw 9 at the free end of which is coupled a first rack 10 with single toothing 10a slidably mounted longitudinally in the chamber 2a of the casing 2, by guide means which have only been 'sketched in the figures. The rack 10 meshes with a pinion 11 which is

  caught in a yoke 12 to which the cable 1 is attached.

  The pinion 11 also meshes with a second rack 13 with double toothing 13a and 13b also slidably mounted in the casing 2 by guide means, shown, similarly, in a simplified manner. This second rack 13 meshes with a transmission pinion 14 which constitutes the outlet of the section

  manual actuation S2 as described below.

  Section S2 manual actuation is shown

  more particularly in FIGS. 4 to 7E.

  It comprises a drum 15 rotatably mounted around a

  axis X-X on a shaft 16 in the chamber 2b of the casing 2.

  On this drum 15 is wound a traction cable 17 attached by one end to this drum and carrying at its opposite end a gripping ring 18 or the like by which manual traction can be exerted on the cable 17, at a location outside the casing 2, this place being able to be chosen remote from the latter for example on the dashboard of the vehicle, the cable being able to be

  guided in a sheath (not shown) provided for this purpose.

  The casing 2 can thus be installed at any location in the vehicle, in particular outside the area between the front seats and more generally outside the passenger compartment of the vehicle. In this way, the space provided between the front seats is free of any space, in particular by a parking brake lever so that it can be used for example to install comfort elements, such as a boot

  storage, cooler, or the like.

  The shaft 16 carries a pinion 19 meshing with a toothed wheel 20 wedged at the end of a second shaft 21 of axis Y-Y rotatably mounted in the chamber 2b, the axis Y-Y being parallel to the axis X-X. A worm screw 22 is cut on a part of the shaft 21. A nut plate 23 is screwed onto this worm screw and immobilized in rotation by a finger 24 which is integral with it and which slides in a

  rectilinear guide 25 provided parallel to the axes X-X and Y-

  Y in the housing 2. The plate 23 carries hooks 26.

  A cylindrical sleeve 27 is mounted in longitudinal translation and in rotation in the chamber 2b along the axis Y-Y which coincides with its own axis, by means of guide means which have not been shown. At one of its ends, this sleeve has a flange 28 which hangs behind the hooks 26 of the nut plate 23. The bore of this sleeve has rectilinear grooves at 27a and 27b, interrupted in an area 27c o the bore of the sleeve is smooth. Two toothed wheels 29 and 30 are fixed respectively on the shaft 22 and on a shaft 31 on which is also fixedly fixed the transmission pinion 14. These toothed wheels cooperate respectively with the

  internal splines 27a and 27b of the sleeve 27.

  As shown in FIGS. 7A to 7E in particular, the actuation section S2 also includes a latching assembly 32 with release by quick release which is sometimes called "brake reel" used for example for blinds or projection screens. More specifically, on the end of the shaft 16 opposite the pinion 19 is provided a cam 33 comprising two notches 34a and 34b of rectangular shape at its periphery. With this cam cooperates a pawl 35 urged against the cam by a spring 36 (shown only in FIG. 7A) and articulated in the wall of the chamber 2b of the casing 2. The active tip of this cam has a blocking surface 35a which, when the tip is engaged in one of the notches 34a or 34b, is applied against one of the side walls of the latter. This blocking surface 35a is connected to two oblique exhaust surfaces 35b and

35c.

  It should be noted that the parking brake has in its unit U2 an elastic return device (symbolized by the spring r in the rectangle U2 in FIG. 1) urging the brake shoes M associated with the wheels R to loosen, which causes traction on the cable 1. This traction is transmitted by means of the mechanism of section S2 on the drum 15 in a direction tending to wind the cable 17 for manual actuation on

this drum.

  The operation of this parking brake is as follows. A - Motorized action This operating mode is shown in Figures 1 and 2. In Figure 1, the brake is fully released and the traction cable 1 is tensioned by the elastic return device R of the brake shoes M. When the driver acts on the button 6 to control the application of the brake, the motor 4 is supplied via the adjustment loop 5 as a function of the braking demand expressed by the degree of rotation of the button 6 and this up to that the signal representing

  this request equalizes the signal supplied by the sensor 7.

  The screw 9 is screwed into the rack 10, which drives the toothed wheel 4 (to the left in FIGS. 1 and 2), this wheel being able to roll on the corresponding toothing 13a of the rack 13. A traction is then exerted on the cable 1 in the direction of application of the parking brake against the action of the elastic return device R of the jaws M. The maximum application position is shown in Figure 2. A release of the brake occurs when , at the request of the driver, the adjustment loop 5 turns the motor 4 in the direction

reverse to release the cable 1.

  B- Manual action It can intervene in the event of an emergency or in the event of a breakdown, for example of the vehicle's on-board power supply system or the adjustment loop 5.

  two cases should be distinguished.

  B-1 The brake is not applied by the motorized action.

  (Situation in FIG. 1) When the conductor pulls on the cable 17 by means of the ring 18, the drum is driven in the direction of the arrow F1 in FIG. 7A. Therefore, it rotates the pinion 19, the toothed wheel 20, the screw 22 and the toothed wheel 29. At the same time, the nut plate 23 is screwed onto the screw 22, driving with it the sleeve 27. In a firstly, the toothed wheel 29 remains in engagement with the sleeve 27 in the zone 27a (FIG. 4). But after a few turns of the toothed wheel 20, the sleeve 27 has moved over a distance such that the toothed wheel 29 enters the area 27c of the sleeve devoid of grooves (Figure 5). The sleeve 27 therefore stops rotating while it continues to move in the axial direction along the Y-Y axis. As long as the sleeve was in the zone 27a, the wheel 14 was rotated by means of the shaft 31, driving with it the rack 6 and consequently the wheel 11. The cable 1 was therefore momentarily pulled in the direction of parking brake application. However, the movement was not sufficient to cause effective tightening. It will also be noted that the pawl 35 has not prevented the operations from taking place since it has escaped

  at the notches 34a and 34b thanks to the exhaust face 35c.

  As traction continues to be exerted on the cable 17, the sleeve 27 will again come into engagement with the toothed wheel 29, but this time in the grooved zone 27c (FIG. 6). Thus, the sleeve is again rotated so that the pulling on the cable 1 can continue via the toothed wheel 30, the shaft 31, the wheel 14, the rack 13 and the wheel 11. The brake can thus be applied until

  tightening with the maximum possible force.

  When the operator slightly and gently releases the cable 17, the shaft 16 rotates in the direction of winding the cable 17 (direction of the arrow F2 in FIG. 7A). Consequently, the hook 35 will have time to descend into one of the notches 34a or 34b of the cam 33 and the rotation of the shaft 16 will be stopped. The parking brake remains applied with the clamping force selected by

the driver.

  To then release the brake, the driver must only pull lightly on cable 17, so that the

  tip of hook 35 may be about halfway

  path between notches 34a and 34b. If under these conditions, it quickly releases the cable 17, the tip of the hook will quickly cross the notches 34a and 34b thanks to the exhaust surface 35b, as illustrated in FIGS. 7C, 7D and 7E. Thus, the shaft 16 can rotate freely and the brake is released partially or completely according to the will of the driver. For partial loosening, the slackening of the cable 17 must be greatly slowed down so that the tip of the hook 35 can again be blocked in a notch 34a or 34b by its blocking surface 35a. The force used to release the brake comes from its elastic return device R. B-2 The brake is already applied by the motorized action

(situation in Figure 2).

  If under these conditions, a fault occurs preventing the motorized action from loosening, the vehicle could not leave without the provisions provided for by the invention. However, under these conditions, the cable 17 is entirely wound on the drum 15. If, in the case of the invention, the cable 17 is then pulled, the toothed wheel will be rotated while the sleeve 27 is translated on the YY axis by turning at the same time around this axis. The cable 1 will then undergo a slight additional traction, but as soon as the toothed wheel 29 coincides with the space 27c devoid of grooves, the elastic return device R of the brake will be free to act in the direction of release by driving the cable 1, the wheel 11 rolling on the rack 10, the rack 13, the wheel 14 and the sleeve 27 (the latter in rotation only). The

  vehicle can therefore be moved later.

  The brake can also be applied manually without the motorized unit being able to hamper this action of

  manual tightening, according to the procedure which has been described above

above.

Claims (8)

  1. Motorized parking brake for a motor vehicle comprising a braking unit (U2) associated with the vehicle wheels and an actuation unit (U1) comprising motorized actuation means (Si) and manual actuation means ( S2) of the brake, these units (U1, U2) being connected to each other via a motion transmission link (1), characterized in that said motorized actuation means (S1) and said manual actuation means (S2) are mechanically coupled in parallel to said transmission link (2) so as to be able to act on the latter independently of each other other.   2. Motorized parking brake according to claim 1, characterized in that said transmission link (1) is integral with a toothed wheel (11) meshing with first and second racks (10, 13) movable in longitudinal translation, said said racks respectively forming the motor outputs of said motorized actuating means (S1) and said manual actuation means (S2).   3. Motorized parking brake according to claim 2, characterized in that said motorized actuation means (S1) comprises a drive motor (4), preferably electric, coupled to said first rack (10) in order to be able to cause it the longitudinal translation, as well as an adjustment loop (5) making it possible to control the drive motor (4) in both directions according to a brake setpoint signal.   4. Motorized parking brake according to one   any one of claims 1 to 3, characterized in that   said manual actuation means (S2) comprise a manual traction cable (17) wound on a rotary drum (15) coupled to said second rack (13) via a disengageable coupling mechanism (20 to 30 ), to allow the longitudinal translation of this second rack (13) by unwinding of said cable   of manual traction (17) of said drum (15).   5. Motorized parking brake according to claim 4, comprising jaws (M) associated with the wheels (R) of the vehicle and return means (R) of these jaws (M) in the released position of the brake, characterized in that said drum (15) is mounted on a rotary shaft (16) to which is coupled a latching assembly (32) with release by quick release, the locking action of which opposes the action of said   return means (R) of the jaws (M).   6. Motorized parking brake according to one   any one of claims 4 and 5, characterized in that   that said disengageable coupling means comprise a sleeve (27) which is mounted movable in translation and in rotation and whose internal bore is grooved in first and second zones (27a, 27b) and devoid of grooves in a third zone ( 27c) intermediate between the first and second zones, and in that toothed wheels (29, 30) mesh with these grooves and are respectively coupled to said second rack (13) and to said drum (15), said sleeve (27) being further coupled in translation to said drum (15) to allow sliding of one of said toothed wheels (29, 30) from said first or second zone towards said third zone or vice versa.   7. Motorized parking brake according to one   any of claims 4 to 7, characterized in that   that said manual traction cable (17) is sheathed and   ends up on the dashboard of the vehicle.   8. Motorized parking brake according to claim 7, characterized in that said motorized and manual actuation means (S1 and S2) are housed in a common housing (2) placed outside the passenger compartment of the vehicle.