The present invention relates generally to mechanical link systems for a pedal device.
In prior art it is known to optimize fuel consumption by using accelerator pedals wherein exaggerated depressing of the accelerator is prevented. In US US20100294074A1 a first return spring exerting urging force to return a pedal to a rest position is arranged in a pedal apparatus. A reaction force adding mechanism is further added to the apparatus comprising a lockable movable member serially arranged in relation to the first return spring. A lock member controlled by an actuator is further controlled based on a detection signal stating that the driver is in state of depressing the accelerator pedal. Upon detection of a depressing state, the lock preventing movement of the movable member is activated whereby the total spring reaction force increases and so the resistance force against the thread force of the driver. Hence, excessive depression by the driver can be suppressed.
A drawback of such accelerator pedal apparatus is the added complexity that comes with requiring an intelligent system based on sensors and actuators to define a wanted thread force curve.
An object of the present invention is to alleviate some of the disadvantages of the prior art and to provide a mechanical link system for a pedal device which is simpler, cheaper, and more robust.
Another object of the present invention is to provide a mechanical link system for a pedal device which facilitates the creation of a plurality of separate pedal force curves depending on the need and requirements present.
According to one embodiment of the invention, a mechanical link system for a pedal device, is provided, the mechanical link system comprising:
a bracket device, a pedal arm pivotally arranged in relation to the bracket device at a first portion of the pedal arm, wherein the pedal arm is pivotable between at least a first position, a second position and a third position upon increasing or reducing a load on the pedal arm, wherein the pedal arm is unloaded in the first position and wherein an increasing load is required to pivot the pedal arm to the third position from the first position via the second position, a first link arm, a second link arm, a first spring device, a second spring device, wherein the pedal arm is mechanically interconnected to the first link arm, wherein a first portion of the first link arm is pivotally arranged to a first portion of the first spring device, and wherein a second portion of the first spring device is arranged to the bracket device, wherein a first portion of the second link arm is pivotally arranged to the bracket device, wherein a second portion of the second link arm is pivotally arranged to a second portion of the first link arm, wherein a third portion of the second link arm is connected to a first portion of the second spring device, wherein a second portion of the second spring device is arranged to the bracket device, wherein the pivoting of the pedal arm from the first position towards the second position causes the first spring device to be compressed at a higher rate than the second spring device, wherein the pivoting of the pedal arm from the second position to the third position causes the second spring device to be compressed at a higher rate than the first spring device.
According to another embodiment, the pedal arm is mechanically interconnected to the first link arm via a guide element that is slidingly connected to the first link arm.
According to one embodiment, the pedal arm is pivotally arranged to the guide element, at a third portion of the pedal arm, wherein a slide portion of the third link arm is slidingly arranged on the first link arm.
According to one embodiment, the slide portion comprises at least a hysteresis element adapted to slide against a surface portion of the first link arm.
According to one embodiment, the hysteresis element comprises a friction pad.
According to one embodiment, the distance from the first position (2a) to the third position of the pedal arm is between 30% to 20% of the overall length of the pedal arm 2, i.e. the distance between the end portions 2a and 2b.
According to one embodiment, the length l2 of the second link arm is in the range of 75%≦l2≦125% of the length l1 of the first link arm.
According to one embodiment, wherein a relative angle, between the pedal arm and the first link arm when the pedal arm is in a first position, is preferably between 40° and 75°, wherein the relative angle is more preferably between 45° and 55°
According to one embodiment, the first spring device has a lower spring force than the second spring device.
According to one embodiment, the first spring device has a first spring rate k1 in the range of 4 N/mm≦k1≦40 N/mm, more preferably in the range of 7 N/mm≦k1≦15 N/mm, most preferably 10 N/mm.
According to one embodiment, the second spring device has a second spring rate k2 in the range of 5 N/mm≦k2≦25 N/mm, more preferably in the range of 8 N/mm≦k2≦16 N/mm
According to one embodiment, the pedal device is a brake pedal device, an accelerator pedal device or a clutch pedal device.
The invention is now described, by way of example, with reference to the accompanying drawings, in which:
In the following, a detailed description of the invention will be given. In the drawing figures, like reference numerals designate identical or corresponding elements throughout the several figures. It will be appreciated that these figures are for illustration only and are not in any way restricting the scope of the invention.
A second link arm 7 is pivotally arranged to the bracket device 5 at a first portion 7a of the second link arm 7. According to one embodiment, the second link arm 7 is pivotally arranged to the bracket device 5 by the aid of a pivot shaft 7a′. According to one embodiment, the first portion 7a is arranged at an end portion of the second link arm 7. A second portion 7b is pivotally arranged to the first link arm 6, at the second portion 6b of the first link arm 6. According to one embodiment, the first and second link arms 6, 7 are pivotally connected by the aid of a pivot shaft 6b′. According to one embodiment, the second link arm 7 has a length l2, i.e. the distance from 7a to 7b, in the range of 75%-125% of l1. According to one embodiment, l2 is 69 mm.
The bracket 5 may be arranged to a second bracket 4 or the vehicle body (none shown), by the aid of bolts, or a screws and nut connection.
A first spring device 8 is arranged to the first link arm 6 at a first portion 8a of the first spring device 8. According to one embodiment, the first portion 8a is pivotally arranged to the first link arm 6 via a pivot shaft, preferably the pivot shaft 6a′. A second portion 8b of the first spring device 8 is arranged to the bracket 5. According to one embodiment, the second portion 8b is connected to the bracket 5 in a loose articulated manner. According to one embodiment, the first spring device 8 is pivotally arranged to the bracket 5, via a pivot shaft 8b′. According to one embodiment, the first spring rate k1 of the first spring device 8 is in the range of 4 N/mm≦k1≦40 N/mm, more preferably in the range of 7 N/mm≦k1≦15 N/mm. According to one embodiment, the first spring rate is 10 N/mm. According to one embodiment, the first spring rate is lower than the spring rate of the second spring device 9. According to one embodiment, the first spring device 8 may comprise a plurality of springs. According to one embodiment, the plurality of springs may be arranged coaxially in relation to each other. According to one embodiment, the plurality of springs may have different spring rates.
A second spring device 9 is arranged to the second link arm 7 at a first portion 9a of the second spring device 9. According to one embodiment, the first portion 9a of the second spring device is arranged to a third portion 7c of the second link arm 7. According to one embodiment, the first portion 9a of the second spring device is arranged to the second link arm 7 in a loose articulated manner. According to one embodiment, the second spring device 9 is pivotally arranged to the second link arm 7, via a pivot shaft 7c′. A second portion 9b of the second spring device 9 is arranged to the bracket 5. According to one embodiment, the second portion 9b is connected to the bracket 5 in a loose articulated manner. According to one embodiment, the first spring device 9 is pivotally arranged to the bracket 5, via a pivot shaft 9b′. According to one embodiment, the second spring rate k2 of the second spring device 9 is in the range of 5 N/mm≦k2≦25 N/mm, more preferably in the range of 8 N/mm≦k2≦16 N/mm. According to one embodiment, the spring rate of the second spring 9 is lower than the spring rate of the first spring device 8. According to one embodiment, the second spring device 9 may comprise a plurality of springs. According to one embodiment, the plurality of springs may be arranged coaxially in relation to each other. According to one embodiment, the plurality of springs may have different spring rates.
According to one embodiment, the brake pedal device 10 may be used in an electrical brake system, often referred to as brake-by-wire, wherein position sensors tracks the position of the pedal arm 2 to generate a corresponding brake force on the wheels, to simulate the feel of a traditional mechanical brake system. In brake-by-wire systems, the driver may experience discomfort since the common relationship between pedal force and brake force allowing a driver to drive in a balanced and safe manner without such simulation is not present. Further, in the brake-by-wire system fail-safe brake capabilities need to be provided, wherein a mechanical braking function sets in if the electrical brake would fail for any reason. A challenge is to combine the existence of a mechanical link system 1 simulating the feel and pedal force and the mechanical braking function, so that the mechanical brake function may be used without requiring an unrealistically high compression force. In essence, during normal driving, the driver compresses the pedal arm 2 so that its position is anywhere between the first and third positions. In a panic situation, i.e. during hard breaking, the pedal force may be in the position X between the second and third position. The line in
A preferred embodiment of a mechanical link system for a pedal device according to the invention has been described. However, the person skilled in the art realizes that this can be varied within the scope of the appended claims without departing from the inventive idea.
All the described alternative embodiments above or parts of an embodiment can be freely combined without departing from the inventive idea as long as the combination is not contradictory.
Number | Date | Country | Kind |
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1450869-1 | Jul 2014 | SE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/SE2015/050730 | 6/24/2015 | WO | 00 |