GB2404967A

GB2404967A - A motor vehicle pedal assembly with a setable pivot axis position

Info

Publication number: GB2404967A
Application number: GB0319113A
Authority: GB
Inventors: Christopher James Slaney
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2003-08-14
Filing date: 2003-08-14
Publication date: 2005-02-16
Anticipated expiration: 2023-08-14
Also published as: GB2404967B; GB0319113D0

Abstract

In a pedal assembly 10 for a motor vehicle the position of the pivot axis of a lever 9 can be set. In one embodiment, the axis position is set by means of two eccentric bushes 20 rotatably located in arms 7,8 of a bracket 5. The bushes 20 can be located in the arms by various means eg a roll pin 24, fastener, welding, splines. The pedal lever may also have an eccentric member (130, fig 7) to allow the pedal length to be set. Another embodiment has only one eccentric bush. A further embodiment, a plastic moulded or pressed metal brackets are made in a common tool having an indexable feature such as an eccentrically mounted punch for positioning an axis aperture in the bracket. Thus the axis position and pedal length can be altered (figs 4-6) for different vehicle models to achieve a desired mechanical ratio while keeping positions of a pushrod connection aperture 14 and foot pad (16 fig 4) relative to the vehicle is substantially unchanged.

Description

A Pedal Assembly for a Motor Vehicle This invention relates to motor

vehicles and in particular to a pedal assembly for a motor vehicle used to provide a foot operable means for operating a braking system or clutch system of the motor vehicle.

It is well known to provide a pedal assembly for a motor vehicle having a lever pivotally connected at its upper end to part of the body structure of a motor vehicle by means of a bracket. It is a problem with existing pedal assemblies that a different bracket has to be made for differing vehicles in a range of vehicles due to the need to use different length levers or differing mechanical ratios. For example an MPV or mini-van will often require a longer lever than a standard car but will often use the same mechanical ratio as a standard car whereas a sports car may require the use of the same length lever as a standard car but may require a higher mechanical ratio.

In the past this has required the manufacture of different brackets for these types of vehicles which is an added cost as the tooling required to manufacture each bracket is expensive.

It is an object of this invention to provide a pedal assembly for a motor vehicle that has increased adaptability so as to allow the use of a common bracket for a number of different vehicles in a range of vehicles.

According to a first aspect of the invention there is provided a pedal assembly for a motor vehicle comprising a bracket assembly connected to part of a body structure of a motor vehicle, the bracket assembly being arranged to pivotally support a lever for rotation about a pivot axis wherein means are provided to permit the position of the pivot axis of the lever relative to the body structure of the motor vehicle to be set in more than one position.

The means to permit the position of the pivotal axis of the lever relative to the body structure of the motor vehicle to be set in more than one position may comprise at least one eccentric member interposed between the lever and the bracket assembly.

Preferably, there may be two eccentric members, one positioned on each side of the lever.

The or each eccentric member may be an eccentric bush. Each eccentric bush may have an outer circumferential surface for engagement with a respective aperture in the bracket assembly and a bore eccentrically positioned relative to the outer circumferential surface.

A pivot shaft may be connected to the lever for engagement with the bore in the or each eccentric bush.

The bracket assembly may comprise of a backplate and two arms, each of the arms may have a respective aperture therein to support an eccentric bush.

The or each eccentric bush may be provided with a means to locate it in at least two different rotational positions in the bracket assembly.

The means to locate the or each eccentric bush may comprise of a pin engageable with respective indentations in the or each eccentric bush and the aperture in the bracket assembly. Alternatively, the means to locate each eccentric bush may comprise of a number of serrations in the aperture in the bracket assembly and a number of serrations on the outer surface of the or each eccentric bush. As yet a further alternative, the means to locate each eccentric bush may comprises of one of an indentation and a projection on an end face of the or each bush for co- operation with an assembly tool during assembly of the or each bush to the bracket assembly. - 3

The lever may be provided with means to change the mechanical ratio of the lever. In which case, the means may be an eccentric member.

According to a second aspect of the invention there is provided a motor vehicle having a pedal assembly in accordance with said first aspect of the invention.

According to a third aspect of the invention there is provided a method for providing series of a pedal assemblies for a motor vehicle in which each pedal assembly has a lever with a pivot axis at an upper end thereof and a bracket assembly for connection to part of a body structure of a motor vehicle and having an aperture used to pivotally support the lever the method comprising manufacturing a series of bracket assemblies in which the location of the aperture in the bracket assembly is different in each bracket assembly of the series wherein all of the bracket assemblies are made on a common tool having an indexable feature used to alter the position in which the aperture is positioned on each of the bracket assemblies.

Each bracket assembly may be manufactured from sheet metal and the indexable feature may be an eccentric punch in the press tool. Alternatively, each bracket assembly may be moulded from a plastic material and the indexable feature may be an eccentric insert in the moulding tool.

The invention will now be described by way of example with reference to the accompanying drawings, of which: Fig.1 is a pictorial representation of a pedal assembly according to the invention; Fig.2 is a pictorial representation similar to Fig. 1 but showing the pedal assembly in a partly assembly state; - 4 - Fig.3 is an end view of an eccentric bush forming part of the pedal assembly shown in Figs l and 2; Fig.4 is a side view of the pedal assembly shown in Fig.1; Fig.5 is a side view similar to Fig.5 but showing the pedal assembly set in an alternative position in which a longer lever is used but in which there is no change in the mechanical ratio of the pedal lever assembly; Fig.6 is a side view similar to Fig.4 but showing the pedal assembly set in an alternative position in which the same length lever is used but in which there is a change in the mechanical ratio of the pedal lever assembly; and Fig.7 is a pictorial representation of a device to vary the mechanical ratio of a lever.

With particular reference to Figs. 1 to 4 there is shown a pedal assembly 10 comprising a bracket assembly 5 and a lever 9 pivotally connected at its upper end to the bracket assembly 5.

The bracket assembly 5 comprises of a backplate 6 and two outwardly projecting support arms 7, 8 each of which has an aperture 12 formed therein. The backplate 6 is used to connect the two support arms 7, 8 to part of the body structure of the motor vehicle such as a bulkhead 2a.

Each of the apertures 12 has an indentation 13 formed in it to provide a location means used to accurately rotationally position a respective eccentric bush 20 fitted into the aperture 12 so that there is one eccentric bush 20 located on each side of the lever 9.

Each eccentric bush 20 has an outer circumferential surface 22 for engagement with the aperture 12 in the support arm 7, 8 with which it is engaged and three indentation 23 in - 5 the outer peripheral surface 22 for co-operation with the indentation 13 in the respective aperture 13 to provide the means for locating the eccentric bush 20 in one of three positions. It will be appreciated that there could be a differing number of indentations in the eccentric bush 20 and that the aperture 12 could be provided with a number of indentations and the eccentric bush with only one. When one of the indentations 23 in the eccentric bush 20 is aligned with the indentation 13 in the aperture 12 a pin and in this case a roll pin 24 can be pushed into place to securely locate the eccentric bush 20 in the desired rotational position. However it will be appreciated that any suitable method of maintaining the bushes in the desired rotational position during the life of the vehicle could be used.

The bushes could for example be of a top hat shaped and have means formed in the rim of the bushes for engagement with respective features formed on the surface of the support arms.

Various means such as threaded fasteners, split pins, welding and adhesive bonding can be used to secure the eccentric bushes 20 in position but in the embodiment shown the eccentric bushes 20 are an interference fit in the apertures 12.

Each eccentric bush 20 has a bore 21 extending therethrough for cooperation with a pivot shaft 11 fastened to the lever 9. The axis of the bore 21 is offset a distance 'E' from the axis of the bush 20 which is positioned centrally relative to the outer circumferential surface 22. A longitudinal axis extending along the length of the pivot shaft 11 defines a pivot axis for the lever 9.

An aperture 14 formed in the lever 9 is used to connect the lever 9 to a device to be operated such as a brake master cylinder, brake servo or clutch master cylinder by means of a pushrod 15 (only shown on Fig.6). - 6

The mechanical ratio of the pedal assembly is determined by the respective length of the lever 9 compared to the distance of the position of connection of the lever 9 to the device to be operated.

In use the application of a force to the end of the lever 9 by an operator via a foot pad 16 will cause initial rotation of the lever 9 about its upper end and transfer force via the aperture 14 to the device to be operated.

The invention can be better understood with particular reference to Figs. 4 to 6. In Fig.4 a pedal assembly for a standard motor vehicle is shown. The length 'L1' of the lever is 0.25m and the distance 'd1' of the aperture 14 from the pivot axis is 0.065m providing a mechanical ratio of 3.85. That is to say if 100N is applied to the lever 9 then a force of 385N will be transferred to the device to be operated.

In Fig.5 a pedal assembly for an MPV (multi-purpose vehicle) is shown in which the length 'L2' of the lever 9 is 0.3m and so is longer than the lever used in the standard car, however the mechanical ratio is the same because the distance 'd2' between the pivot axis and the position of aperture 14 has also been increased to 0.078m. However the position of the aperture 14 relative to a floor 2b and bulkhead 2a of the motor vehicle body structure has not significantly changed. This has been achieved by positioning the eccentric bush 20 in a different rotational position in Fig.5 compared to Fig.4.

By rotating the eccentric bush 20 from the position shown in Fig.4 to the position shown in Fig. 5 the position of the pivot axis of the lever 9 relative to the body structure of the motor vehicle has been set in a different position. In Fig.5 the pivot axis is further from the floor 2b and is slightly closer to the bulkhead 2a than it is in Fig.4 The vertical position of the pivot axis can be determined from the formula: - 7 P1 = Y*(E*sin O) where P1 is the vertical height of the pivot axis from the floor 2b, Y is the vertical height of the centre of the apertures 12 from the floor 2b, E is the eccentricity in the bush 20 and 0 is the rotational position of the eccentric bush 20 in the aperture 12.

The horizontal position of the pivot axis can be determined from the formula: P2 = X*(E*cos O) where P2 is the horizontal distance of the pivot axis from the bulkhead 2a, X is the horizontal distance of the centre of the apertures 12 from the bulkhead 2a, E is the eccentricity in the bush 20 and 0 is the rotational position of the eccentric bush 20 in the aperture 12.

In Fig.6 there is shown a pedal assembly for a sports car, in this pedal assembly the length 'L3' of the lever is 0.25m which is the same as the standard vehicle but the distance d3' of the aperture 14 from the pivot axis is reduced to 0.06m giving a mechanical ratio of 4.2. That is to say, if 100N is applied to the lever 9, then a force of 420N will be transferred to the device to be operated. This is useful for a sports car because quite often a heavy duty clutch is required to transmit the higher engine power torque often used in such vehicles. Such a heavy duty clutch will normally utilise a higher clutch clamp load than a conventional clutch and so requires more applied force to release it. Similarly, it is often required to provide more braking effort in a sports type vehicle because the output from the lever needs to be greater due to the higher potential speeds, the increased braking effort required or because harder brake pads are often used.

However, it should be noted that the position of the aperture 14 relative to a floor 2b and bulkhead 2a of the motor vehicle body structure has once again not changed significantly.

Therefore, by using the invention, virtually the same location is used for the brake servo or master cylinder in all three cases even though the mechanical ratio or the length of the lever has been significantly changed. - 8

It will be appreciated that the dimensions given for the lever and positioning of the aperture 14 are merely illustrative and that various other dimensions could be used.

In a modification of the embodiment previously described, in which different levers are required to provide different mechanical ratios, the lever can be provided with a means to change the mechanical ratio. Such a means is shown in Fig. 7 in the form of an eccentric member 130 engaged with an aperture in the end of a lever 109. The eccentric member has two spigots 111 extending outwardly therefrom for engagement with the eccentric bushes previously described and is located in position by means of a pin 131 engaged with recesses 132, 133 formed in the aperture and the eccentric member 130. The spigots 111 provide the means for pivotally connecting the lever 109 to a bracket assembly (not shown) fitted to the motor vehicle and so determine the position of the pivot axis of the lever relative to the lever 109.

It will be appreciated that by rotating the spigots 111 through approximately 180 from the position shown in Fig.7 the length of the lever 109 will be increased. However, it will be further appreciated that rotation of the spigots 111 will also change the mechanical ratio of the lever because not only is the length of the lever 109 changed but also the distance from the pivot axis to the position of connection of the device to be operated is changed.

It will be further appreciated that although the invention has been described with reference to the use of two eccentric bushes interposed between the bracket assembly and the lever to provide a means of setting the position of the pivot axis other eccentric devices could be used. For example there could be one eccentric bush located on one side of the lever and one device having an eccentrically position pivot shaft or spigot on the other side of the lever.

It will also be appreciated that other means could be used to determine the rotational orientation of the eccentric bushes relative to the bracket assembly. For example, the - 9 - means to locate each eccentric bush could comprises of a number of serrations in the aperture in the bracket assembly and a number of serrations on the outer surface of the or each eccentric bush. Such serrations could be in the form of splines. Alternatively, the means to locate each eccentric bush could comprise of one of an indentation and a projection on an end face of the or each bush for co-operation with an assembly tool during assembly of the or each bush to the bracket assembly. The indentation or projection being used to position the eccentric bush before it is secured in place by welding or other means.

As an alternative to the device previously described, an eccentric device could be used in the manufacture of the bracket assembly to economically produce bracket assemblies having the apertures located in different positions.

In the case of a bracket assembly produced from sheet metal each bracket assembly could be manufactured using a press tool with an indexable feature such as an eccentrically mounted punch. The punch tool is mounted such that it can be locked in one of a number of pre-determined positions corresponding to the required position for the aperture to suit a particular vehicle. All of the features of each bracket assembly would then be identical except for the positioning of the apertures which would be determined based upon the proposed use of the bracket assembly.

In the case where each bracket assembly is moulded from a plastic material, the indexable feature would be an eccentrically mounted insert in the moulding tool.

Therefore by manufacturing on a common tool having an indexable feature used to alter the position in which the aperture is positioned on each of the bracket assemblies, a series of bracket assemblies in which the location of the aperture in the bracket assembly is different in each bracket assembly of the series is economically produced. Such a method requires the manufacture of only one manufacturing tool and so the tooling costs - 1 0 are greatly reduced compared to the current situation in which each type of bracket assembly is made on a separate manufacturing tool.

It will appreciated by those skilled in the art that the invention has been described by way of example with reference to several specific embodiments but that it is not so limited and that other embodiments or modifications to the embodiments disclosed could be made without departing from the scope of the invention. - 11

Claims

1. A pedal assembly for a motor vehicle comprising a bracket assembly connected to part of a body structure of a motor vehicle, the bracket assembly being arranged to pivotally support a lever for rotation about a pivot axis wherein means are provided to permit the position of the pivot axis of the lever relative to the body structure of the motor vehicle to be set in more than one position.

2. A pedal assembly as claimed in claim 1 wherein the means to permit the position of the pivotal axis of the lever relative to the body structure of the motor vehicle to be set in more than one position comprises at least one eccentric member interposed between the lever and the bracket assembly.

3. A pedal assembly as claimed in claim 2 in which there are two eccentric members, one positioned on each side of the lever.

4. A pedal assembly as claimed in claim 2 or in claim 3 wherein the or each eccentric member is an eccentric bush.

5. A pedal assembly as claimed in claim 4 wherein each eccentric bush has an outer circumferential surface for engagement with a respective aperture in the bracket assembly and a bore eccentrically positioned relative to the outer circumferential surface.

6. A pedal assembly as claimed in claim 5 wherein a pivot shaft is connected to the lever for engagement with the bore in the or each eccentric bush.

7. A pedal assembly as claimed in any of claims 4 to 6 wherein the bracket assembly comprises of a backplate and two arms, each of the arms having a respective aperture therein to support an eccentric bush. - 1 2

8. A pedal assembly as claimed in any of claims 4 to 7 wherein the or each eccentric bush is provided with a means to locate it in at least two different rotational positions in the bracket assembly.

9. A pedal assembly as claimed in claim 8 wherein the means to locate the or each eccentric bush comprises of a pin engageable with respective indentations in the or each eccentric bush and the aperture in the bracket assembly.

10. A pedal assembly as claimed in claim 8 wherein the means to locate the or each eccentric bush comprises of a number of serrations in the aperture in the bracket assembly and a number of serrations on the outer surface of the or each eccentric bush.

11. A pedal assembly as claimed in claim 8 wherein the means to locate the or each eccentric bush comprises of one of an indentation and a projection on an end face of the or each bush for co-operation with an assembly tool during assembly of the or each bush to the bracket assembly.

12. A pedal assembly as claimed in any of claims 1 to 11 in which the lever is provided with means to change the mechanical ratio of the lever.

13. A pedal assembly as claimed in claim 12 in which the means is an eccentric member.

14. A motor vehicle having a pedal assembly according to any of claims 1 to 13.

15. A method of providing series of a pedal assemblies for a motor vehicle in which each pedal assembly has a lever with a pivot axis at an upper end thereof and a bracket assembly for connection to part of a body structure of a motor vehicle and having an aperture used to pivotally support the lever the method comprising manufacturing a series of bracket assemblies in which the location of the aperture in the bracket - 1 3 assembly is different in each bracket assembly of the series wherein all of the bracket assemblies are made on a common tool having an indexable feature used to alter the position in which the aperture is positioned on each of the bracket assemblies.

16. A method as claimed in claim 15 wherein each bracket assembly is manufactured from sheet metal and the indexable feature is an eccentric punch in the press tool.

17. A method as claimed in claim 15 wherein each bracket assembly is moulded from a plastic material and the indexable feature is an eccentric insert in the moulding tool.

18. A pedal assembly substantially as described herein with reference to the accompanying drawings.

19. A method substantially as described herein with reference to the accompanying drawing.