DE102019215491A1 - Pedal actuation unit - Google Patents

Abstract

The invention relates to a pedal actuation unit (100) with a displaceably mounted brake pedal (102) and a return mechanism, the return mechanism being designed to apply a return force to the brake pedal (102) in the direction of its rest position when the brake pedal (102) is deflected from its rest position cause. The reset mechanism has at least a first (110) and a second reset device (112). According to the invention, it is provided that the brake pedal (102) is connected to the reset mechanism via a scissor mechanism.

Description

The invention relates to a pedal operating unit.

Pedal actuation units known in the prior art are often hydraulically connected to a brake pedal simulator, the brake pedal simulator simulating the pedal feeling expected by a vehicle driver when a brake pedal is actuated. In normal operation of a brake system with such a pedal actuation unit, there is no direct hydraulic connection between the brake pedal and the wheel brakes per se. Rather, the brake pressure derived from actuation of the pedal actuation unit in the wheel brakes is generated by an often electromechanical pressure supply device in combination with a corresponding hydraulic valve circuit.

In a hydraulic fall-back level, a direct hydraulic connection between the pedal unit and the wheel brakes can be established through appropriate control of the hydraulic brake system or a corresponding valve circuit, so that a failure of the pressure supply device can be at least partially compensated for.

For modern vehicle architectures, however, a pure “drive-by-wire” solution is becoming increasingly relevant, in which there is no longer a hydraulic connection between the pedal actuation unit and the hydraulic brake system. Such a pedal actuation unit should, however, still convey the feeling of a hydraulic brake system to a vehicle driver.

The present invention is based on the object of creating a pedal actuation unit which, without a hydraulic connection to the brake system, provides a vehicle driver with a familiar brake actuation feeling when a pedal is actuated.

This object is achieved with the pedal actuation unit according to claim 1.

Advantageous refinements of the invention are the subject of the dependent claims.

In a first aspect, the invention relates to a pedal actuation unit with a displaceably mounted brake pedal and a reset mechanism, the reset mechanism being designed to effect a reset force on the brake pedal in the direction of its rest position when the brake pedal is deflected from its rest position, the restoring mechanism at least a first and a second reset device. According to the invention it is provided that the brake pedal is connected to the reset mechanism via a scissor mechanism.

Due to the scissor mechanism used, the pedal actuation unit according to the invention has the advantage that the pedal actuation unit can be made more compact overall, since the installation space usually required for a pedal lever is eliminated. The pedal actuation unit is designed completely without hydraulic components, so that the pedal actuation unit is maintenance-free and almost wear-free. Due to the lack of a hydraulic connection from the pedal actuation unit to the actual hydraulic brake system, the pedal actuation unit can furthermore be positioned largely freely in the footwell of a vehicle. A brake request is transmitted from the pedal actuation unit to the brake system in a purely electronic way.

The restoring force on the brake pedal in the direction of its rest position preferably increases continuously with the degree of deflection of the brake pedal from its rest position.

According to a preferred embodiment it is provided that the pedal actuation unit has a support structure, the scissors mechanism being articulated on one side of the support structure. The support structure can be, for example, a one-piece component on which the different elements of the pedal actuation unit are arranged and attached, the support structure in turn being able to be attached to the vehicle body, for example on a bulkhead of the vehicle, so that the pedal actuation unit relative to the Vehicle is set. The support structure preferably consists of a metal.

To articulate the scissors mechanism on the support structure, a further embodiment provides that a first scissors arm of the scissors mechanism is guided in a link arranged on the support structure and a second scissors arm of the scissors mechanism is mounted in a fixed bearing arranged on the support structure, so that when the As a brake pedal, the first scissor arm is displaced in the setting and the second scissor arm is pivoted about a first pivot axis defined by the fixed bearing. A further embodiment provides that the link is formed in the supporting structure. For example, the backdrop can be milled out of the supporting structure. Consequently, a movement of the scissors mechanism is completely determined by the support structure or the guide elements formed on the support structure.

As already stated above, the reset mechanism has a first and a second reset device. To realistically simulate the pedal feel of a classic hydraulic braking device, a further embodiment provides that the restoring force is increased, in particular exclusively, by the first restoring device over a first displacement range of the brake pedal and that the increase in the brake pedal is increased over a second displacement range of the brake pedal Restoring force, in particular exclusively, is brought about by the second restoring device.

By appropriately designing the individual resetting devices, it can be achieved, for example, that only a comparatively small resetting force acts on the brake pedal over the first displacement area, while the resetting force increases exponentially over the second displacement area adjoining the first displacement area. The first displacement range corresponds to the initial bridging of a clearance of a wheel brake when the brake is actuated, with only a small restoring force acting on the brake pedal. As soon as the clearance is overcome and the friction lining is in contact with the brake disks, the restoring force on the brake pedal increases very sharply when the brake pedal is pressed again, which is due to the deformation of the friction lining and the wheel brake itself that takes place from this point on. This strong increase in the restoring force can then be represented by the second restoring device.

To represent the restoring force over the first displacement range, it is provided according to a further embodiment of FIG. 1 that the first restoring device has a torsion spring. The torsion spring is preferably designed in such a way that it only opposes a deformation with a small restoring force. The restoring force is preferably just so great that a brake pedal is driven back in its rest position, but only a small force is required to move the brake pedal from its rest position.

In particular, another embodiment is provided that the torsion spring has a first spring leg and a second spring leg, the torsion spring exerting a restoring force on the spring legs in the direction of the rest position when the angle between the first spring leg and the second spring leg changes from a rest position of the spring legs to one another the spring leg causes. The torsion spring can then be articulated to the actuation mechanism of the brake pedal via the spring legs of the torsion spring.

For this purpose, it is provided according to a further embodiment that the second scissor arm has a driver element which is designed to engage in the first spring leg of the torsion spring. The entrainment element can be, for example, a pin, avoided bolt, which is preferably connected to the scissor arm in a materially bonded manner, or is made in one piece with the scissor arm.

In order to compress the torsion spring when the scissor arm is displaced, an abutment for a second spring leg of the torsion spring is necessary. Accordingly, according to a further embodiment it is provided that the second spring leg of the torsion spring is supported on a pivotably mounted spring washer. The spring washer can for example consist of a metal and is preferably made in one piece. Furthermore, according to a further embodiment it is provided that the spring washer is mounted pivotably about the first pivot axis. According to a further embodiment, it is preferably also provided that the torsion spring is mounted on the first pivot axis.

In order to support the spring washer against rotation about the first pivot axis, a further embodiment provides that the second restoring device is articulated with a first end on the spring washer. According to a further embodiment, the articulation point of the second restoring device on the spring washer is preferably spaced apart from the first pivot axis. As a result, the second restoring device can produce a torque on the spring washer, which counteracts a torque exerted on the spring washer by the first restoring device or the torsion spring and consequently initially prevents the spring washer from rotating.

The second return device is designed in a more preferred embodiment in such a way that the second return device has a spiral spring and at least one elastic element, in particular an elastomer. According to a further embodiment, the arrangement of the elastic element and the spiral spring is chosen so that the increase in the restoring force caused by the second restoring device is brought about over a first force range only by the spiral spring and over a second force range by the spiral spring and the elastic element.

As a result, the second restoring device provides a force-displacement characteristic which is divided into two areas. In a first area, the restoring force that is brought about by the second restoring device initially only increases slightly, the restoring force being caused solely by the Coil spring is provided. This first area is followed by a second area in which the restoring force caused by the second restoring device increases sharply with further compression of the restoring device, which is brought about by the combination of spiral spring and elastic element. This corresponds to the behavior of a classic hydraulic brake, in which, after an initial, easy-to-accomplish compression of the friction linings, when the wheel brake is actuated further, deformation of the brake caliper also increasingly contributes to the restoring force on the brake pedal.

According to a further embodiment, a particularly compact design of the second restoring device is achieved in that the elastic element is formed within the spiral spring. According to a further embodiment, the second reset device is preferably designed in the form of a spring strut.

To this end, according to a further embodiment, it is further provided that the elastic element is annular or tubular so that it can be arranged in the spring strut within the spiral spring, the elastic element preferably enclosing a guide element of the spring strut.

In order to bring about a compression of the spiral spring when the spring strut is compressed, a further embodiment provides that the second return device has two spring plates, between which the spiral spring is arranged.

As already stated above, the restoring mechanism is preferably designed such that a restoring force is brought about by the first restoring device over a first region, while the restoring force is brought about by the second restoring device over a second region. For this purpose, it is provided according to a further embodiment that the spring washer has a radial projection, the entrainment element of the second scissor arm coming into engagement with the radial projection after pivoting the second scissor arm by a defined pivot angle. As a result, as soon as the entrainment element of the second scissor arm strikes the radial projection, the spring washer moves with a movement of the second scissor arm, so that the torsion spring is no longer compressed from this point in time. Rather, from this point in time, the restoring force is provided solely by the second restoring device. Consequently, the position of the radial projection defines the point at which a transition from the first reset device to the second reset device takes place. The force-displacement characteristic of the pedal actuation unit can therefore be adjusted by appropriate positioning of the radial projection.

In order to provide an abutment for a compression of the second restoring device, it is provided according to a further embodiment that the second restoring device is fastened with a second end to the support structure. Furthermore, according to a further embodiment, it is provided that the first pivot axis is mounted in the support structure.

The driver brake request is preferably detected by sensors on the mechanical elements.

To determine a brake actuation signal indicating the driver's brake request when the pedal actuation unit is actuated, a further embodiment provides that the pedal actuation unit has at least one sensor device that is designed to detect the degree of deflection of the brake pedal from its rest position. The degree of deflection can then be converted into a brake actuation signal that is transmitted to the brake system or a corresponding control device. A brake pressure is then generated by the brake system on the basis of the brake actuation signal.

According to a preferred embodiment, it is provided that the sensor device is designed to determine an angle of rotation of the second scissor arm about the first pivot axis relative to its rest position. For this purpose, according to a preferred embodiment, the sensor device is arranged on the first pivot axis.

Alternatively or additionally, the sensor device can also be designed to determine a linear displacement of at least one element of the scissors mechanism. An actuation signal can then likewise be derived from a known transmission ratio of the scissors mechanism between a displacement of the brake pedal and a displacement of the monitored element.

• - Die Pedalbetätigungseinheit kann im Fußraum eines Fahrzeugs frei positioniert werden,
• - die Verbindung von Fußraum zu Motorraum kann hinter dem Bremspedal entfallen, da die zur Steuerung der Bremsanlage benötigten Signale über andere Wege übermittelt werden,
• - die Pedalbetätigungseinheit ist wartungsfrei, da keine Flüssigkeiten enthalten sind,
• - die Pedalbetätigungseinheit ist nahezu verschleißfrei, da keine Dichtelemente vorhanden sind,
• - Es sind keine Präzisionsbauteile notwendig, sodass die Pedalbetätigungseinheit kostengünstig hergestellt werden kann,
• - Es ist eine geschlossene Bauweise möglich, sodass keine Pedalblockade auftreten kann
• - Bezüglich der Sensorauswahl und Positionierung der Sensorik kann die Pedalbetätigungseinheit flexibel angepasst werden,
• - Die Pedalkennlinie kann auf einfache Art und Weise durch Änderung der Rückstellvorrichtungen angepasst werden,
• - Durch das integrierte elastische Element ist eine kompakte Bauweise möglich,
• - Die erzeugte Pedalkennlinie weist aufgrund der Reihenschaltung der Rückstellvorrichtungen keine Unstetigkeiten auf,
• - Es ist eine einsatzspezifische Modulbauweise möglich.

The possible advantages of a previously described pedal actuation unit are:

• - The pedal actuation unit can be freely positioned in the footwell of a vehicle,
• - The connection from footwell to engine compartment behind the brake pedal can be omitted, as the signals required to control the brake system are transmitted via other channels,
• - the pedal actuation unit is maintenance-free as it does not contain any liquids,
• - the pedal actuation unit is almost wear-free as there are no sealing elements,
• - No precision components are necessary, so that the pedal actuation unit can be manufactured inexpensively,
• - A closed construction is possible so that no pedal blockage can occur
• - With regard to the sensor selection and positioning of the sensors, the pedal actuation unit can be flexibly adapted,
• - The pedal characteristic can be easily adapted by changing the reset devices,
• - The integrated elastic element enables a compact design,
• - The generated pedal characteristic has no discontinuities due to the series connection of the resetting devices,
• - A use-specific modular design is possible.

• 1 eine Explosionsdarstellung einer Pedalbetätigungseinheit,
• 2 eine Detaildarstellung einer als Federbein ausgebildeten zweiten Rückstellvorrichtung,
• 3 eine perspektivische Ansicht der Pedalbetätigungseinheit,
• 4 eine weitere perspektivische Ansicht der Pedalbetätigungseinheit und
• 5 eine seitliche Ansicht der Pedalbetätigungseinheit.

In the following, preferred embodiments of the invention are explained in more detail with reference to the drawings. Show:

• 1 an exploded view of a pedal operating unit,
• 2 a detailed representation of a second resetting device designed as a spring strut,
• 3 a perspective view of the pedal actuation unit,
• 4th a further perspective view of the pedal operating unit and
• 5 a side view of the pedal actuator.

In the following, similar or identical features are identified with the same reference symbols.

The 1 shows an exploded view of a pedal operating unit 100 with a brake pedal 102 , which is slidably mounted along an actuating path. A perspective view of the same pedal operating unit 100 is in the 3 and 4th specified. The brake pedal 102 is operated by the driver. This causes the scissor arms to fold 202 , 204 , 206 and 104 together. In doing so, the bolts form 208 and 210 Fixed bearing for the scissor arms 204 and 104 so that the scissor arms 204 and 104 around the through the bolts 208 and 210 defined axes are pivotably mounted.

Bolts 212 and 214 are, however, slidably mounted in corresponding guide slots. Here is the leadership backdrop 216 in the supporting structure 218 educated. When the brake pedal is shifted 102 towards the supporting structure 218 the bolt is in 214 by a first scissor arm 206 in the leadership backdrop 216 linearly shifted. This linear shift is in the form of a path signal through the sensor device 130 detected and used to determine a driver brake request.

On the through the bolt 210 defined first pivot axis is a second scissor arm 104 , a spring washer 120 and a torsion spring 110 pivoted.

The desired force-displacement curve of the pedal actuation unit 100 The torsion spring is connected in series 110 as the first reset device and the shock absorber 112 achieved as a second reset device. First presses when the brake pedal is pressed 102 and a pivoting of the second scissor arm brought about as a result of the scissors mechanism 104 around the second pivot axis 210 the driving element 114 of the second scissor arm 104 on a first spring leg 116 the torsion spring 110 . The second spring leg 134 is based on the spring washer 120 starting around the first pivot axis 210 is pivoted. On the spring washer 120 is also the shock absorber 112 hinged on one side, the corresponding pivot point 136 from the first pivot axis 210 is spaced. As a result, the strut is propelling 112 the spring washer 120 in their rest position. The rest position is through the scissor mechanism through the stop of the bolt 214 at the lower end of the guide gate 216 set.

After a certain travel of the brake pedal 102 and a corresponding rotation of the second scissor arm 104 , the entrainment element comes 114 in engagement with a radial projection 118 the spring washer 120 so that the force of the entrainment element 114 directly on the spring washer 120 is transmitted. The torsion spring 110 then no longer contributes to an increase in the restoring force generated. From here on the strut is alone 112 in engagement.

The strut 112 is in 2 shown in detail. To the required characteristic of a progression towards the end of the brake pedal actuation path 102 a tubular elastic element is shown 122 , preferably an elastomer, in the strut 112 inserted and inside the spiral spring 124 of the shock absorber 112 arranged. The spiral spring 124 is in turn between two spring plates 140 and 142 clamped, which a compression of the shock absorber 112 on the spiral spring 124 transfer. With increasing compression of the shock absorber 112 becomes the elastic element 122 from the cylinder 126 of the shock absorber 112 compressed from a certain degree of compression.

To detect an actuation of the brake pedal 102 is on the supporting structure 218 the pedal actuation unit 100 furthermore the sensor device 132 arranged that a rotation of the second scissor arm 104 around the first pivot axis 210 can detect. The electrical signals detected in this way can then be used in a corresponding actuation path of the brake pedal 102 and thus a driver brake request can be converted. The braking system of a vehicle in which the pedal operating unit 100 is arranged, can then be controlled according to the detected driver brake request.

The previously described pedal actuation unit 100 is in the 3 , 4th and 5 again shown in the assembled state in different views.

In summary, the idea of the invention is based on the design of a mechanical pedal actuation unit without hydraulic fluid. The pedal feel is simulated by switching springs to represent the force-displacement characteristic curve that is usual for a brake pedal. The path to be recorded is translated into a scissor mechanism. This means that the usual pedal arm can be dispensed with, which enables a more compact design.

Claims (17)

Pedal actuation unit (100) with a displaceably mounted brake pedal (102) and a resetting mechanism, the resetting mechanism being designed to bring about a resetting force on the brake pedal (102) in the direction of its rest position when the brake pedal (102) is deflected from its rest position The reset mechanism has at least a first (110) and a second reset device (112), characterized in that the brake pedal (102) is connected to the reset mechanism via a scissor mechanism. Pedal actuation unit (100) according to one of the preceding claims, characterized in that the increase in the restoring force, in particular exclusively, is brought about by the first restoring device (110) over a first displacement range of the brake pedal (102) and that over a second displacement range of the brake pedal (102 ) the increase in the restoring force, in particular exclusively, is brought about by the second restoring device (112). Pedal actuation unit (100) Claim 1 or 2 , characterized in that the pedal actuation unit (100) has a support structure (218), the scissor mechanism being articulated on one side of the support structure (218). Pedal actuation unit (100) Claim 3 , characterized in that a first scissor arm (206) of the scissors mechanism is guided in a link (216) arranged on the supporting structure (218) and a second scissor arm (104) of the scissor mechanism is mounted in a fixed bearing arranged on the supporting structure (218), so that when the brake pedal (102) is deflected, the first scissor arm (206) is displaced in the link (216) and the second scissor arm (104) is pivoted about a first pivot axis (210) defined by the fixed bearing. Pedal actuation unit (100) according to one of the preceding claims, characterized in that the first restoring device (110) has a torsion spring (110). Pedal actuation unit (100) Claim 5 , characterized in that the torsion spring (110) has a first spring leg (116) and a second spring leg (134), with a change in the angle between the first spring leg (116) and the second spring leg (134) from a rest position of the spring leg (116, 134) the torsion spring (110) causes a restoring force on the spring legs (116, 134) in the direction of the rest position of the spring legs (116, 134). Pedal actuation unit (100) Claim 6 , characterized in that the second scissor arm (104) has a driver element (114) which is designed to engage in the first spring leg (116) of the torsion spring (110). Pedal actuation unit (100) Claim 6 or 7th , characterized in that the second spring leg (134) of the torsion spring (110) is supported on a pivotably mounted spring washer (120). Pedal actuation unit (100) Claim 8 , characterized in that the spring washer (120) is mounted pivotably about the first pivot axis (210). Pedal actuation unit (100) Claim 8 or 9 , characterized in that the spring washer (120) has a radial projection (118), wherein the entrainment element (114) of the second scissor arm (104) after pivoting the second scissor arm (104) by one defined pivot angle comes into engagement with the radial projection (118). Pedal actuation unit (100) according to one of the Claims 8 to 10 , characterized in that the second return device is articulated with a first end on the spring washer (120). Pedal actuation unit (100) Claim 11 , characterized in that the articulation point (136) of the second return device (112) on the spring washer (120) is spaced from the first pivot axis (210). Pedal actuation unit (100) according to one of the preceding claims, characterized in that the second return device (112) has a spiral spring (124) and at least one elastic element (122), in particular an elastomer. Pedal actuation unit (100) Claim 12 , characterized in that the increase in the restoring force caused by the second restoring device (112) is brought about over a first force range only by the spiral spring (124) and over a second force range by the spiral spring (124) and the elastic element (122). Pedal actuation unit (100) according to one of the previous ones Claims 2 to 14th , characterized in that the second return device is attached to the support structure (218) at a second end. Pedal actuation unit (100) according to one of the preceding claims, characterized in that the pedal actuation unit (100) has at least one sensor device (130, 132) which is designed to detect the degree of deflection of the brake pedal (102) from its rest position. Pedal actuation unit (100) according to one of the preceding claims, characterized in that the sensor device (132) is designed to determine an angle of rotation of the second scissor arm (104) about the first pivot axis (210) relative to its rest position.

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