Brakes – Vehicle
Reexamination Certificate
1999-01-06
2001-02-27
Oberleitner, Robert (Department: 3613)
Brakes
Vehicle
Reexamination Certificate
active
06193022
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an actuation device for a cable-operated parking brake of a motor vehicle and which enables actuation of the parking brake selectively by muscular energy or with a motive power assist, the actuation device including a muscular energy-actuated member for actuating the parking brake, an auxiliary motor for actuating the parking brake, a brake cable tightening device, and a drive for actuating the brake cable tightening device and including, first and second drive elements connected, respectively, with the muscular energy-actuated member and the auxiliary motor, and a connection element for selectively connecting one of the first and second drive elements with the brake cable tightening device.
2. Description of the Prior Art
Actuation devices of the type described above, with which a parking brake can be selectively actuated either by muscular energy or by an auxiliary motor, in particular, an electric motor, find lately ever increasing application in motor vehicles for improving an operational comfort of motor vehicles. Actuation devices of this type are available in many different embodiments.
Besides relatively simple actuation devices, with which the parking brake is actuated, during a normal course of operation, by an electric auxiliary motor and only in case of an abnormal occurrence, with a conventional brake lever by applying a muscular energy thereto, there exist actuation devices with which the parking brake can be arbitrary actuated either with a conventional hand brake lever or a pedal by applying a muscular energy thereto, or with a switch-actuated electric auxiliary motor. One of such actuation devices for an arbitrary selection of the type of actuation of a parking brake is disclosed in German Publication DE-OS 32 10 402. In the disclosed actuation device, a force transmitting member, which transmits the force applied to the pivotal hand brake lever to a tightening element of the parking brake, is formed as a cable secured to the hand brake lever at a distance from the pivot axis of the hand brake lever. Besides, the cable is enveloped by an electromotor-driven friction wheel, with the electromotor being secured either to the hand brake lever or being secured on the vehicle body, separately from the hand brake lever. In this actuation device, the electromotor actuating switch is mounted on the hand brake lever. When the hand brake lever is pivoted, to apply the brake, upward, the electromotor is actuated and the friction wheel transmits a power-assist force, which is added to the actuation force applied to the hand brake lever, to the cable-shaped power transmitting member. Actuation of the parking brake only with the electromotor in not possible with this actuation device.
In another known actuation device for a motor vehicle parking brake, a hand brake lever, which pivots about a stationary axle and is retained in different pivotal position by a pawl, is connectable with a cable pulley which forms a tightening element for the cable and is supported on the same axle as the hand brake lever. A drive connects an electromotor with the cable pulley. For selectively actuating the hand brake either with the hand brake lever or with the electromotor, there is provided a manually-operated clutch which alternatively or selectively connects the cable pulley, which forms the brake cable tightening device, with either manually operated hand brake lever or with an auxiliary drive including the electromotor. This actuation device provides for both actuation of the parking brake only by muscular energy and actuation of the parking brake only by the electric motor. However, this known actuation device has increased dimensions because the hand brake lever, the tightening element, the switching clutch, and a drive pinion of the electromotor-operated drive need be arranged in a row. Therefore, this actuation device can be fitted in a motor vehicle with a pedal-operated parking brake only with great difficulties and with significant additional expenses.
Accordingly, an object of the present invention is an actuation device for a motor vehicle parking brake which would insure a selective actuation of the parking brake either by muscular energy or with electromotive energy assist, while requiring a smaller mounting space in a motor vehicle.
Another object of the present invention is an actuation device of the above-described type which is characterized by reduced technical expenses.
SUMMARY OF THE INVENTION
These and other objects of the present invention which will become apparent hereinafter, are achieved by forming the drive for actuating the tightening device as a planetary gear drive having a first drive member connectable with the first drive element, a second drive member connectable with the second drive element, and a third drive member connected with the tightening device thereby connecting the first and second drive element selectively with the tightening device.
The use of a planetary gear drive permits to provide means which are formed of inexpensively produced elements and are characterized by small dimensions and which, at the same time, provides for selective or alternating driving of the tightening element with different sources of the driving force. Simultaneously, the use of a planetary gear drive permits to provide a switching element having a simple construction and easily mountable, in particular, a switching element or its actuation element, e.g., a button which is spaced from the planetary gear drive and is located in a vehicle in a place where it is easily accessible to the driver. In addition, the use of a planetary gear drive permits to realize different transmission ratios for actuation the parking brake by a muscular energy and by motorized force.
In an advantageous embodiment of the present invention, the first drive member, which is connected with the drive element driven by the muscular energy-actuated member, is formed as a sun gear of the planetary gear drive, and the second drive member, which is connected with the drive element driven by the auxiliary motor, is formed as a planet wheel carrier of the planetary gear drive. For selectively connecting the drive element, which is driven by the muscular energy-actuated member, with the first drive element, the sun gear, and the drive element, which is driven by the auxiliary motor, with the second drive member of the planetary gear drive, the planet wheel carrier, selectively, the planet wheel carrier on the sun gear, is respectively, blocked. The sun gear and the planet wheel carriers are blocked with respective blocking means which are associated with respective drive elements.
To reduce the constructional dimensions of the actuation device, it is contemplated to form the tightening device, at least partially, as a cable pulley with which the ring gear of the planetary gear drive, which forms the third drive member, is connected for joint rotation therewith. This embodiment of the actuation device contemplates forming the cable pulley and the ring gear as an integral part.
With regard to actuation of the parking brake by muscular energy, it is contemplated to form the muscular energy-actuated member, which drives the drive element associated with the first drive member of the planetary gear drive, the sun gear, as per se known hand brake lever pivotally supported on a motor vehicle body and connected by a control cable and a cable pulley with the sun gear. Alternatively, the muscular energy-actuated member, which drives the drive element connected with the sun gear of the planetary gear drive, can be formed as per se known pedal pivotally supported on the vehicle body and likewise connected with the sun gear by the control cable and the respective cable pulley.
Independent from whether the muscular energy-actuated member is formed as a hand brake lever or a pedal, according to a preferred embodiment of the present invention, the cable pulley, which is associated with the control cable connected with the first drive
Brown & Wood LLP
ED. Scharwachter GmbH
Oberleitner Robert
Talavera Melanie
LandOfFree
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