Actuator for moving a brake booster during a collision

Abstract

A brake booster is mounted on a forward bulkhead of a motor vehicle having two elements, a first element being securely connected to the brake booster whilst a second element is securely connected to the bulkhead. The two elements are restrained against vertical movement relative to one another by at least one connector which is deformed or fails upon a movement of the brake booster upward relative to the bulkhead. An actuator is movably mounted to the bulkhead below the brake booster and rearward of a gearbox housing such that rearward movement of the gearbox housing during a frontal collision presses against the actuator and moves the actuator upward to apply pressure to the brake booster, the pressure causing the brake booster to move upward relative to the bulkhead.

Claims

1. Apparatus comprising: a brake booster; a rear mounting element secured to a vehicle front bulkhead; a forward mounting element secured to the brake booster and engaging the rear mounting element to mount the brake booster to the bulkhead, the engagement between the rear and forward mounting elements permitting upward movement of the forward mounting element relative to the rear mounting element when upward pressure applied to the brake booster exceeds a limit-value; and an actuator pivotably mounted to the bulkhead below the brake booster and rearward of a vehicle component such that rearward movement of the vehicle component during a frontal collision causes the actuator to rotate upward and apply upward pressure to the brake booster exceeding the limit-value.

2. The apparatus of claim 1, further comprising at least one connector engaging the first and second elements to resist relative movement therebetween until the pressure applied by the actuator to the brake booster exceeds a limit-value.

3. The apparatus of claim 1, wherein the connector comprises a bolt extending through mutually aligned first and second bores defined by the front and rear mounting elements respectively.

4. The apparatus of claim 1, wherein the front and rear mounting elements each define a through-hole passing therethrough, the through-holes aligned with one another and with an opening in the bulkhead to permit a brake pedal rod to pass therethrough.

5. The apparatus of claim 4, wherein the through-holes are elongated in a direction of movement of the brake booster relative to the bulkhead.

6. Apparatus comprising: a brake booster mounted to a vehicle forward bulkhead for movement upward relative thereto when upward pressure applied to the brake booster exceeds a limit-value; and an actuator pivotably mounted to the bulkhead below the brake booster and rearward of a gearbox housing such that rearward movement of the gearbox housing during a frontal collision causes the actuator to rotate upward and apply upward pressure to the brake booster exceeding the limit-value.

7. The apparatus of claim 6 further comprising a mounting device, the mounting device comprising: a first element secured to the bulkhead; and a second element secured to the brake booster and engaged with the first element to mount the brake booster to the bulkhead, the engagement between the first and second elements permitting the second element to move upward along with the brake booster when the actuator applies pressure to the brake booster.

8. The apparatus of claim 7, wherein the first element and the second element each define a through-hole passing therethrough, the through-holes aligned with one another and with an opening in the bulkhead to permit a brake pedal rod to pass therethrough.

9. The apparatus of claim 8, wherein the through-holes are elongated in a direction of movement of the brake booster relative to the bulkhead.

10. The apparatus of claim 7, further comprising at least one connector engaging the first and second elements to resist relative movement therebetween until pressure applied by the actuator to the brake booster exceeds a limit-value.

11. The apparatus of claim 10, wherein the connector comprises a bolt extending through mutually aligned first and second bores defined by the first and second elements respectively.

12. The apparatus of claim 7, wherein the first and second element each define a through-hole passing therethrough, the through-holes aligned with one another and with an opening in the bulkhead to permit a brake pedal rod to pass therethrough.

13. The apparatus of claim 12, wherein the through-holes are elongated in a direction of movement of the brake booster relative to the bulkhead.

14. Apparatus comprising: a brake booster mounted to a vehicle forward bulkhead; and an actuator movably mounted to the bulkhead below the brake booster and rearward of a gearbox housing such that rearward movement of the gearbox housing during a frontal collision presses against the actuator and moves the actuator upward to apply pressure to the brake booster, the pressure causing the brake booster to move upward relative to the bulkhead.

15. The apparatus of claim 14, wherein the actuator is pivotably mounted to the bulkhead and rotates about a pivot axis to apply pressure to the brake booster.

16. The apparatus of claim 14 further comprising a mounting device, the mounting device comprising: a first element secured to the bulkhead; and a second element secured to the brake booster and engaged with the first element to mount the brake booster to the bulkhead, the engagement between the first and second elements permitting the second element to move upward along with the brake booster when the actuator applies pressure to the brake booster.

17. The apparatus of claim 16, wherein the first element and the second element each define a through-hole passing therethrough, the through-holes aligned with one another and with an opening in the bulkhead to permit a brake pedal rod to pass therethrough.

18. The apparatus of claim 17, wherein the through-holes are elongated in a direction of movement of the brake booster relative to the bulkhead.

19. The apparatus of claim 16, further comprising a connector engaging the first and second elements to resist relative movement therebetween until the pressure applied by the actuator to the brake booster exceeds a limit-value.

20. The apparatus of claim 19, wherein the connector comprises a bolt extending through mutually aligned first and second bores defined by the first and second elements respectively.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic side view of a gearbox housing and a brake booster with an actuator;

(2) FIG. 2 is a schematic section in the Z-X plane through an embodiment of a mounting device for a brake booster in normal operation;

(3) FIG. 3 is a schematic section 3-3 through a mounting device according to FIG. 2;

(4) FIG. 4 is a schematic section 4-4 through a mounting device according to FIG. 2;

(5) FIG. 5 is a schematic section in the Z-X plane through a mounting device according to FIG. 2 after a displacement of the brake booster;

(6) FIG. 6 is a front view of a first embodiment of a rear mounting element;

(7) FIG. 7 is a front view of a second embodiment of a rear mounting element;

(8) FIG. 8 is a front view of a second embodiment of a forward mounting element; and

(9) FIG. 9 is a schematic section 9-9 through a mounting device according to FIG. 8.

DETAILED DESCRIPTION

(10) As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

(11) In the different figures, the same parts are always denoted by the same reference signs and are therefore generally also only described once.

(12) The schematic side view of FIG. 1 shows a vehicle forward powertrain compartment including a brake booster 10. In particular, the brake booster 10 may be an electric brake booster. The view of FIG. 1 represents a view of the powertrain compartment looking along the Y direction of the motor vehicle in which it is installed. The brake booster 10 is fastened to a forward bulkhead 30 of a motor vehicle and is connected in a known manner with a brake pedal and a brake system of the motor vehicle (not illustrated). The brake booster 10 is mounted on the bulkhead 30 via a multipart mounting device 50. To the right of the bulkhead 30, there is the vehicle compartment with the footwell of the driver. The bulkhead 30 here is merely illustrated schematically and can be designed in known ways.

(13) A gearbox housing 40, 40 is shown located immediately forward of the actuator 20 in the engine compartment. An upper portion/extent of the gearbox housing 40, 40 is immediately forward of at least a lower portion/extent of the brake booster 10. That is, there is vertical overlap between the gearbox housing 40, 40 and the brake booster 10.

(14) An actuator 20 is mounted on the bulkhead 30 below the brake booster 10. This actuator is formed substantially by an arm which is pivotably mounted on the bulkhead 30 via a pivot axis 21. The pivot axis 21 of the actuator 20 extends in the Y direction. The actuator 20 is mounted below the brake booster 10 such that its free end (the end distal from the pivot axis 21) faces in the direction of the underside of the brake booster 10. In normal operation of the motor vehicle, this distal end of the actuator 20 may be in contact with the underside of the brake booster 10 or may be located at a slight spacing from the underside of the brake booster 10. The actuator 20 projects from the bulkhead 30 and is held in this position by holding clips (not illustrated) or a corresponding clamping force in the pivot axis 21.

(15) FIG. 1 shows the actuator 20 at the moment in which, as a result of a frontal vehicle collision, the gearbox housing has moved rearward from its normal position 40 (illustrated in dashed line) into a displaced position 40 (illustrated in solid line) and has contacted the actuator 20 on its lower or convex side. The actuator 20 is thus urged by the rearward movement of the gearbox housing to pivot upwards about its pivot axis 21, contacts the underside of the brake booster 10 and applies pressure to the brake booster pushing it upwards (in the direction of the arrow) and causing it to move upward relative to the bulkhead 30.

(16) The force of the gearbox housing 40 in the X direction has therefore advantageously been converted by the actuator 20 into a force on the brake booster 10 in the Z direction. The load path between the gearbox housing 40 and the brake booster 10 in the X direction is thus redirected to include a component in the Z direction which raises the brake booster relative to the bulkhead 30. The gearbox housing 40 can then move under the brake booster 10 or the brake booster 10 can slide with its underside along the upper side of the gearbox housing 40.

(17) So that the brake booster 10 can slide upward along the bulkhead 30 in a controlled manner, the mounting device 50 is constructed in at least two parts. FIG. 2 shows the two elements 51 and 52 of the mounting device 50. The first or forward element 51 is mounted on the brake booster 10, which is illustrated by dashed lines. This may be achieved by a plurality of fastening points, for example in the form of screw connections, of which two screw connections 61 and 62 are shown. Since this first element 51 can move together with the brake booster 10 during a vehicle frontal collision, it is also referred to below as a movable element. A second or rear element 52 is mounted on the bulkhead (not illustrated). This likewise takes place via a plurality of fastening points, of which two fastening points 63 and 64 are shown. This second element 52 is also referred to below as a fixed element, since it does not move relative to the bulkhead.

(18) The elements 51, 52 are formed by profiled plates which lie parallel to one another. The elements 51, 52 here are secured against movement relative to one another via at least one connector 60. In the embodiment of FIG. 2, a connector 60 in the form of a bolt or shear pin is shown. This bolt 60 passes through and is retained in bores in the first and second element, which are aligned with one another. Both elements 51, 52 furthermore each have a through-hole 53 and 54, which are likewise aligned with one another. The push rod 80 of a brake pedal (shown in FIG. 5) passes through these through-holes 53, 54 to connect the brake booster 10 with a brake pedal (not shown) in the passenger compartment of the vehicle.

(19) The fixed/rear element 52 may be constructed in an L shape in its lower region so as to form a lip projecting from the element 52, which serves as a supporting element 55. The lower end of the movable/forward element 51 lies on this supporting element 55 so that the weight of the brake booster 10 is supported on the supporting element 55.

(20) FIG. 3 shows a schematic section 3-3 through a mounting device 50 according to FIG. 2. It can be seen from this view that the fixed element 52 is mounted within the movable element 51 in a guide. To this end, two slide grooves 70 and 70 are formed in the movable element 51. The fixed element 52 has corresponding slide flanges 71 and 71, which engage and are guided within the slide grooves 70, 70. The two elements 51, 52 are thus displaceable relative to one another in the vertical or Z direction. FIG. 3 furthermore shows the mutually aligned through-holes 53, 54 (to permit passage of the brake pedal push rod) and further fastening points 61 and 63. FIG. 4 shows a schematic section through a mounting device 50, the section taken along a line 4-4 in FIG. 2. The section extends through two connectors 60, 60.

(21) If the brake booster 10 is pushed upwards in the Z direction, shear stresses are produced in the connectors 60, 60. The material and the dimensions of the connectors are selected such that they deform or break when a desired/designed stress is exceeded, thus enabling a movement of the movable/forward mounting element 51 relative to the fixed/rear mounting element 52. The stress at which the connectors fail to allow upward movement is reached when the level of the upward pressure applied to the brake booster 10 by the actuator 20 exceeds a designed limit-value. This limit-value is selected/designed such that the brake-booster 10 is able to move upward and out of the path of the rearward moving housing 40 before the housing applies sufficient force to the gearbox to cause unacceptable damage to any of the structure and/or components of the vehicle.

(22) With this, the shear pins break, as can be seen in FIG. 5 which shows the connector 60 broken into two pieces. The movable element 51 is then able to move upwards, along with the brake booster 10, in the direction of the arrow. The two through-holes 53 and 54 are also displaced with respect to one another here, but the size of the through-holes is selected such that the push rod 80 (illustrated schematically by dashed lines) still passes freely through the mounting device 50 to the brake booster 10 as before.

(23) FIG. 6 shows a front view of a fixed element 52, i.e. the element attached to the bulkhead. From this view, two upper fastening points 63, 63 and two lower fastening points 64, 64 can be seen. The two connectors 60 and 60 and the form of the through-hole 54 can furthermore be seen. This through-hole 54 is formed as an elongated hole whereof the longitudinal alignment extends in the Z direction.

(24) FIG. 6 furthermore shows the two slide elements 71 and 71, which extend on opposite sides of the element 52 in the Z direction. The slide elements 71, 71 do not extend parallel here; rather, the spacing between the two slide elements increases upwards in the Z direction. The spacing B between the two slide elements 71, 71 is greater at the upper end of the element 52 than the spacing b at the lower end. The two slide elements 71, 71 therefore extend to form a V shape together. The same consequently also applies for the associated slide grooves in the movable element.

(25) The slide elements 71, 71 can be constructed continuously in the Z direction here. However, they can also be constructed such that they are interrupted or shortened as in the embodiment of FIG. 7 so that a slide element does not extend fully over the height of a element. The front view of FIG. 8 shows a second embodiment of a movable element, i.e. the element 51 on the brake booster. Analogously to the interrupted slide elements 71 and 71 on the fixed element 52, interrupted slide grooves 70 and 70 are proved on this member. Owing to the interruption of the slide grooves and the slide elements, these can be easily detached from one another in the event of a movement of the brake booster in the Z direction which corresponds to a movement of a few millimeters.

(26) FIG. 9 shows a schematic section 9-9 through a mounting device which has a fixed element 52 according to FIG. 7 and a movable/forward element 51 according to FIG. 8. However, the two elements here are illustrated at a spacing from one another.

(27) While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.