WO2005014354A1

WO2005014354A1 - Parking brake device, particularly for vehicles

Info

Publication number: WO2005014354A1
Application number: PCT/EP2004/008441
Authority: WO
Inventors: Antonio Surian; Maurizio Basso
Original assignee: Nuova S.M.E. S.P.A.
Priority date: 2003-08-07
Filing date: 2004-07-28
Publication date: 2005-02-17
Also published as: ITPD20030181A1

Abstract

A parking brake device particularly for vehicles, comprising an electric gearmotor (11, 111, 211), which is functionally connected to a mechanism (12) for tensioning at least two tension elements (13, 113, 213; 141 114~ 214) for a corresponding number of brakes, the mechanism (12) comprising unidirectional translational motion and tensioning elements (15) for a rocker (16), which is connected by a first end (17, 217) directly to a first tension element (13, 113, 213) and by a second end (18) to a second. tension element (14, 114, 214) with the interposition of elements (19) for balancing the distribution of forces.

Description

PARKING BRAKE DEVICE, PARTICULARLY FOR VEHICLES Technical Field The present invention relates to a parking brake device particularly for vehicles. Background Art Parking brake devices actuated by means of an electric motor or gearmotor driven by an electronic board provided with a control logic system for managing the braking action are currently increasingly widespread in motor vehicles. Such control logic system controls the braking action both by interacting with the driver, by sending an impulse by means of a switch that is within the user's reach, and by acting according to an intelligent logic of assisted driving, such as for example in the case of an uphill start. The manual force for pulling a lever for operating the parking brake is therefore replaced with an easy and quick pressure of a switch for activating the motor or gearmotor. These devices, commonly known as Electric Parking Brakes (EPB), are used in vehicles that provide great comfort to the user and all the more so in vehicles designed to be driven by disabled persons who have difficulty in accessing or handling a manually-operated parking brake, and in general in vehicles in which it is necessary to have space between the front seats of the cabin. Such manual parking brake lever is in fact eliminated from the cabin, and so is the transmission cable that connects the lever to the braking mechanism. Next to the ergonomic advantages, the EPB entails, as mentioned, structural and installation advantages. In addition to eliminating the front cable and the lever from the cabin, the braking device in fact allows to place the actuator, suitable to convert the power delivered by the electric gearmotor or motor into braking force, at the rear axle of the vehicle. In this manner, the actuator, by way of two cables of limited length fixed externally, acts directly on the parking brakes, with important savings on traction cables. Although these devices are widely appreciated by the market, they have aspects that can be improved. In particular, currently known EPBs are provided with a mechanism that has a worm screw suitable to tension, by way of adapted means for distributing the traction force, the traction elements connected to the brakes. Moreover, the EPBs have a double independent outlet for the brake actuation cables. Such worm screw is a component that generally requires careful machining and is therefore expensive to obtain. Disclosure of the Invention The aim of the present invention is to provide a parking brake device that is low in cost and whose compact dimensions can be compared to those of known types. Within this aim, an object of the present invention is to provide a parking brake device that can be installed easily proximate to the rear and/or front axles of a vehicle. Another object of the present invention is to provide a parking brake device that can be easily released mechanically in case of emergency. Another object of the present invention is to provide a parking brake device whose efficiency is not lower than that of known types of parking device. Another object of the present invention is to provide a parking brake device that can be operated easily by means of electronic components of a known type. Another object of the present invention is to provide a device that is structurally simple and can be obtained with great economy of materials and equipment. Another object of the present invention is to provide a parking brake device that can be manufactured with known systems and technologies. This aim and these and other objects that will become better apparent hereinafter are achieved by a parking brake device particularly for vehicles, of the type that comprises an electric gearmotor that is functionally connected to a mechanism for tensioning at least two tension elements for a corresponding number of brakes, characterized in that said mechanism comprises unidirectional translational motion and tensioning means for a rocker that is connected by a first end directly to a first tension element and by a second end to a second tension element with the interposition of means for balancing the distribution of forces. Brief description of the Drawings Further characteristics and advantages of the invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment thereof, illustrated by way of nonlimiting example in the accompanying drawings, wherein: Figure 1 is a perspective view of a device according to the invention; Figure 2 is a top view of a device according to the invention; Figure 3 is a perspective view of a device according to the invention, which includes an electric gearmotor; Figure 4 is a perspective view of a device according to the invention, in a second embodiment thereof; Figure 5 is a top view of a device according to the invention, in a third embodiment thereof; Figure 6 is an exploded perspective view of the third embodiment of Figure 5; Figure 7 is a bottom view of a device according to the invention in the third embodiment, as shown in Figures 5 and 6; Figure 8 is a perspective view of a device according to the invention in a fourth embodiment thereof; Figure 9 is another perspective view of a device according to the invention, in the fourth embodiment of Figure 8; Figure 10 is another perspective view of a device according to the invention, in the fourth embodiment of Figures 8 and 9. Ways of carrying out the Invention With reference to the figures, a parking brake device according to the invention is generally designated, in a first embodiment thereof, by the reference numeral 10. The device 10 comprises an electric gearmotor 11, which is functionally connected to a mechanism 12 for tensioning a first tension element 13 and a second tension element 14, for a corresponding number of brakes, not shown. The mechanism 12 comprises means for unidirectional translational motion and tensioning 15 for a first rocker 16. The first rocker 16 is connected, by a first end 17, directly to the first tension element 13 and, by a second end 18, to the second tension element 14, with the interposition of means 19 for balancing the distribution of forces. The translational motion and tensioning means 15 are constituted by a pusher mechanism 20, which is composed of a first linkage 21 and a crank 22. A pivot 23 of the first rocker 16 is fixed to a sliding block 24 of the first linkage 21. The crank 22 is connected to the first linkage 21 by a rotary pair 22a. The sliding block 24 slides in an appropriately provided guide 25. The means 19 for balancing the distribution of forces are constituted by a second linkage 26 for connection between the second end 18 of the first rocker 16 and a second end portion 29 of a second rocker 28, which oscillates about a fulcrum 35 of the crank 22. A first end portion 27 of the second rocker 28 tensions the second tension element 14. The first tension element 13 and the second tension element 14 are thus arranged substantially parallel to each other and act in opposite directions. The first tension element 13 and the second tension element 14 are constituted by two cables suitable to act only by traction. The crank 22 is constituted by a portion of a toothed sector 30. The toothed sector 30 comprises a set of teeth 31, which forms a monolithic body with the crank 22. The crank 22 and the set of teeth 31 are arranged on opposite sides with respect to the fulcrum 35. The toothed sector 30 engages the electric gearmotor 11 by means of a pinion 32. The mechanism 12 is contained in a protective housing 34 for connection to a motor vehicle body, not shown. The housing 34 is provided with two holes 36 for the passage of the first and second tension elements 13 and 14. Advantageously, in the embodiment described herein, the housing 34 also contains the gearmotor 11. A device 10 like the one described, by way of the two rockers 16 and 28, which face each other so as to form substantially an articulated quadrilateral in which the frame element, i.e., the part whose dimension is the distance between the fulcrum 35 and the pivot 23 and therefore the sliding block 24, has variable dimensions, is extremely compact and can be installed easily even in underbodies in which the available space is limited. All the more so, the device 10 can be installed easily at the rear axle of a motor vehicle, therefore proximate to the brakes, with an important saving of components as regards the transmission cables. The device 10 is conveniently provided with a stroke limiter 38 for the toothed sector 30. The stroke limiter 38 prevents inappropriate movements of the mechanism 12 upon release of the device 10, first of all preventing the toothed sector 30 from rotating excessively, disengaging the set of teeth 31 with respect to the pinion 32. The device 10 also has an emergency release. In the embodiment of the invention described herein, the emergency release is provided, by way of non-exclusive example, by a shaft 39. The pinion 32 is in fact rigidly coupled to a shaft with a hollow hexagonal head 39 that is coaxial thereto. The shaft 39 allows the mechanical release of the device 10 in case of failure of the electrical management system or for any emergency requirement. In a second embodiment of the device according to the invention, designated by the reference numeral 110 in Figure 4, the first and second tension elements 113 and 114 are constituted by two rods capable of operating both by pulling and by pushing. In order to optimize the operation of the tension elements 113 and 114 at each one of the holes 136 there is a framework 150 for providing a clip-on coupling and a corresponding gasket for providing a static seal^' on the wall of the housing 134, both of which are not shown. This type of interface with rigid rods also has the advantage of simplifying the functional testing of the cable-free actuation assembly. In a third embodiment of the device according to the invention, designated by the reference numeral 210 in Figures 5 and 6, the toothed sector 230 is arranged above the second rocker 228, the first linkage 221 and the second linkage 226, instead of below, as in the embodiment designated by the reference numeral 10. The third embodiment has a first tension element 213, which is coupled internally at the first end 217, thus providing more movement space for the second tension element 214, which slides proximate to the first end 217. The third embodiment is further provided with a release shaft 239, with a female hexagonal key-shaped head that protrudes below the housing 234, as shown in Figure 7, while in the first embodiment designated by the reference numeral 10 the female hexagonal key-shaped head protruded upward. This configuration of the manual release device allows even easier access on the part of a user, if emergency operations or simple assistance operations become necessary. Figures 5 and 6 of the third embodiment also illustrate a gear 232a, which is rigidly coupled to the pinion 232 and is suitable to engage directly the gearmotor 211. In all the described embodiments, the device 10, 110, 210 is completed by control electronic components, not shown. Such control electronics is advantageously coupled externally to the housing 34, 134, and 234 of the device 10, 110 and 210 in a protected position inside a sealed container. As an alternative, the control electronics is arranged inside the housing 34, 134 and 234, again inside a sealed protective container. The electronics is connected to the device 10, 110 and 210 by means of an integrated and appropriately sealed connector. As an alternative, the control electronics is remote and is connected to the gearmotor 11, 111 and 211 of the housing 34, 134 and 234 by means of appropriate wiring. Another embodiment of the invention is shown in Figures 8 to 10 and is designated therein by the reference numeral 310. The device 310 has, in a manner similar to what has been described above, an electric gearmotor 311, a mechanism 312 that is composed of a first rocker 316 with its pivot 323, a second rocker 328 with its fulcrum 335, a linkage 321, and tension elements 313 and 314 connected to the mechanism 312. The toothed sector 330 and the pinion 332 meshed therewith are also visible. Such further embodiment is provided with frameworks 350 as described earlier. In this further embodiment the gearmotor 311 is arranged outside the housing 334 and is functionally connected to the toothed sector 330 by means of a gear 340 thereof, which in turn meshes with a reduction gear 332a that is coaxial and rigidly coupled to the pinion 332. Figure 9 illustrates a covering panel 341, which substantially closes the housing 334. A first guide 343 for a slider 342, rigidly coupled to the toothed sector 330, and a second guide 344, for the pivot 323 of the first rocker 316, are provided on the panel 341. The operation of the device 10, and likewise the operation of its different embodiments, can be summarized in the following steps. By means of a switch generally arranged on the dashboard of a motor vehicle, the electric gearmotor 11 is operated. The gearmotor 11, by means of the gear 232a and the rigidly connected pinion 32, turns the toothed sector 30. The crank 22, which belongs to the sector 30, pushes, by means of the rotary pair 22a, the first linkage 21 and with it the sliding block 24 in the guide 25. The pivot 23, rigidly coupled to the sliding block 24, moves the first rocker 16 pivoted thereto. The first rocker 16 tensions the first tension element 13. At the same time, the second rocker 28 is turned by means of the second linkage 26. The rotation of the rocker 28 tensions the second tension element 14. If the first tension element 13 ends its locking stroke first, the gearmotor 11 continues to act on the toothed sector 30, pushing further the first rocker 16 so that it slides with its pivot 23 in the guide 25. In this manner, by way of the second linkage 26, the second rocker 28 continues its rotation until the second tension element 14 also has ended its locking stroke. Likewise, if it is the second tension element 14 that ends its stroke first, the gearmotor 11, by means of the toothed sector 30, pushes the first rocker 16 until the first tension element 13 also has ended its locking stroke. In practice it has been found that the invention thus described solves the problems noted in known types of parking brake device. In particular, the present invention provides a parking brake device that can be installed easily proximate to the rear and/or front axles of a vehicle. Moreover, the present invention provides a parking brake device that is capable of producing, by means of a kinematic system with two degrees of freedom, an equal traction force on both brakes of the wheels of a motor vehicle on which it is installed. Moreover, the present invention provides a parking brake device preset for simple functional testing. Further, the present invention provides a device whose components are simple and economical to manufacture and equally easy to assemble. Not least, the present invention provides a device that can be obtained advantageously by way of known systems and technologies. In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art. The disclosures in Italian Patent Application No. PD2003A000181 from which this application claims priority are incorporated herein by reference.

Claims

CLAIMS 1. A parking brake device (10, 110, 210) particularly for vehicles, of the type that comprises an electric gearmotor (1 1, 111, 211), which is functionally connected to a mechanism (12) for tensioning at least two tension elements (13, 113, 213; 14, 114, 214) for a corresponding number of brakes, characterized in that said mechanism (12) comprises unidirectional translational motion and tensioning means (15) for a rocker (16), which is connected by a first end (17, 217) directly to a first tension element (13, 113, 213) and by a second end (18) to a second tension element (14, 114, 214) with the interposition of means (19) for balancing the distribution of forces.

2. The device according to claim 1, characterized in that said translational motion means (15) are constituted by a pusher mechanism (20), which is composed of a first linkage (21, 211) and a crank (22).

3. The device according to one or more of the preceding claims, characterized in that the pivot (23) of said rocker (16) is fixed to the sliding block (24) of said first linkage (21, 221) suitable to slide in a guide (25).

4. The device according to one or more of the preceding claims, characterized in that said means (19) for balancing the distribution of forces are constituted by a second linkage (26, 226) for connection between said second end (18) of said rocker (16) and a second end portion (29) of a further rocker (28, 228), which oscillates about the fulcrum (35) of said crank (22), a first end portion (27) of said additional rocker (28, 228) tensioning said second tension element (14, 114, 214).

5. The device according to one or more of the preceding claims, characterized in that said crank (22) is part of a toothed sector (30), which is provided with a set of teeth (31) arranged in opposition to said crank (22) with respect to said fulcrum (35) of said crank (22), said electric gearmotor (11, 111, 211) engaging, by way of at least one reduction gear (32, 232), said set of teeth (31).

6. The device according to one or more of the preceding claims, characterized in that said first tension element (13, 113, 213) and said second tension element (14, 114, 214) are substantially parallel.

7. The device according to one or more of the preceding claims, characterized in that said first tension element (13, 113, 213) and said second tension element (14, 114, 214) act in substantially opposite directions.

8. The device according to one or more of the preceding claims, characterized in that said mechanism (12) is contained in a housing (34, 134, 234) for protection and connection to a body of a motor vehicle, said housing (34, 134, 234) being provided with holes (36, 136) for the passage of said first tension element (13, 113, 213) and said second tension element (14, 114, 214).

9. The device according to claim 8, characterized in that said housing (34, 134, 234) contains said electric gearmotor (11, 111, 211).