(51) Int. Cl.⁴:

G 01 M 7/00

(19) Federal Republic of Germany

[emblem]

German Patent Office

(12) Patent

(11) DE 34 21 546 C1

(21) Application number: P 34 21 546.8-51

(22) Filing date: June 8, 1984

(43) Date of disclosure: -

(45) Publication date of

the patent grant: November 14, 1985

Opposition may be filed within 3 months following publication of the grant.

(73) Patent holder: Bayerische Motoren Werke AG, 8000 Munich, DE

(72) Inventors: Lehr, Werner, 8034 Germering, DE; Poser, Erhard, 8031 Alling, DE (56) Publications that were considered to evaluate the patentability, pursuant to §44 of the Patent Act: DE-PS 8 51 648 DE-OS 31 27 910 SAE Journal, Vol. 77, No. 12, December 1969, pp. 43-51

(54) Device for the Controlled Deceleration of a Body, in particular a Motor Vehicle, that is moved Approximately Linearly

Device, which is intended for the controlled deceleration of a body (1), in particular a motor vehicle, that is moved approximately linearly. Said device comprises an operational sequence, which is determined theoretically or in the preceding test, in particular a crash test, and comprises a braking device for the controlled braking of the body (1) and a controlled rearward acceleration device, which is intended for a more accurate simulation of crash tests, and comprises elastic deformation components, which accelerate the body (1) rearwards following its plastic deformation.

DE 3421546 C1

Federal Government Printing Office 09.85 508 146/440 70

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Patent Claims:

1. Device, which is intended for the controlled deceleration of a body, in particular a motor vehicle, that is moved approximately linearly, and which comprises an operational sequence, which is determined theoretically or in the preceding test, in particular a crash test, and comprises a braking device for braking the body, characterized in that the braking device comprises a brake caliper, exhibiting two brake shoes (3, 3'), and a friction rail (2), which extends between the brake shoes (3, 3') in the direction of motion of the body (1); that the brake caliper or the friction rail (2) is connected to a carriage (7), which can be displaced between stops (5, 6) in the direction of motion of the body (1); and that the device comprises a rearward acceleration device, which begins to act approximately following termination of the forward motion of the body (1), exhibits a force transfer device, which acts on the carriage, and acts on the body by way of the friction rail (2) and the brake caliper.

2. Device, as claimed in claim 1, characterized in that the rearward acceleration device accelerates and/or decelerates the body (1) in a controlled manner in the rearward direction.

3. Device, as claimed in claim 1, characterized in that the body (1) is guided in its direction of motion.

4. Device, as claimed in claim 1, characterized in that the cross section of the friction rail (2) is configured in the shape of a rectangle.

5. Device, as claimed in claim 4, characterized in that the friction rail (2) projects downwards from the bottom of the body (1) and that the brake caliper is aimed upwards and is braced on the carriage (7).

6. Device, as claimed in claim 1, characterized in that the carriage (7) is guided by means of rotatable rollers (4).

7. Device, as claimed in claim 5, characterized in that the brake caliper is mounted on the upper side of the carriage (7).

8. Device, as claimed in claim 1, characterized in that during the forward motion of the body (1), the carriage (7) rests against the stop (6), which is located in the direction of this motion.

9. Device, as claimed in claim 1, characterized in that there is an acceleration sensor, which influences the braking force.

10. Device, as claimed in claim 1, characterized in that the force transfer device is operated electrically, pneumatically, hydraulically, or mechanically.

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The invention relates to a device, which is intended for the controlled deceleration of a body, in particular a motor vehicle, that is moved approximately linearly. Said device comprises an operational sequence, which is determined theoretically or in the preceding test, in particular a crash test, and comprises a braking device for braking the body.

A device of this type is known from the SAE Journal, volume 77, number 12, December 1969, pp. 43 - 51. In this case said device provides a controllable hydraulic shock absorber for the

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controlled deceleration of a vehicle or a subunit of said vehicle that is accelerated to the desired speed by a separate drive system. This shock absorber consists in essence of two concentric cylinders, which are provided with apertures on the periphery and which form, as a function of their rotational positions, a different passage cross section for a liquid stream. The one drawback is that not every deceleration event can be predetermined and that the device can deceleration the vehicle or the subunit only in one direction, but cannot accelerate rearwards in the reverse direction.

The DE-PS 8 51 548 discloses a speed brake with two brake shoes, which are located opposite each other so as to be spaced apart and are braced stationarily. Said brake shoes interact with the braking surfaces on a vehicle, when the vehicle travels past the speed brake at a speed that is greater than the predetermined speed. For control purposes, a mechanical drive with uniformly driven friction wheels is connected upstream of the speed brake. With the speed brake it is possible to achieve that a vehicle, which drives past said speed brake, exhibits a specified driving speed. A controlled deceleration or acceleration following a predetermined time signal is neither intended nor possible with this speed brake.

The object of the invention is to further develop a device of the type described in the introductory part so that with said device it is possible to reproduce as accurately as possible over and over again the deceleration and/or rearward acceleration sequence that is theoretically determined or that is determined when a body collides with an obstacle.

This problem is solved with a device of the above described genre in that the braking device comprises a brake caliper, exhibiting two brake shoes, and a friction rail, which extends between the brake shoes in the direction of motion of the body; that the brake caliper or the friction rail is connected to a carriage, which can be displaced between stops in the direction of motion of the body; and that the device exhibits a rearward acceleration device, which begins to act approximately following termination of the forward motion of the body, exhibits a force transfer device, which acts on the carriage, and acts on the body by way of the friction rail and the brake caliper. In this advantageous manner it is possible to consider realistically the influence that is produced owing to the elasticity of the body, when a body collides with an obstacle, and that acts on the body following the plastic deformation and accelerates the body rearwards.

Practical embodiments of the invention are the subject matter of the dependent claims.

One embodiment of the invention is explained with reference to the drawings.

Figure 1 is a diagrammatic sketch of a deceleration device, depicted from the side in a sectional drawing, while the body drives into the brake calipers.

Figure 2 is a front view of the device, depicted in Figure 1.

Figure 3 is a drawing that corresponds to Figure 1, just before the rearward acceleration of the body; and

Figure 4 is a drawing, which corresponds to Figure 1, with the body resting after the rearward acceleration.

Figure 1 is a sectional view of a diagrammatic sketch of a device for the controlled deceleration of a body 1, which is moved approximately linearly and which at this instance is driving in the forward direction into the device.

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The body 1 can travel on rails (not illustrated) and exhibits on its underside a friction rail 2, which is fastened to said underside and is pointed downwards. This friction rail is arranged with its longitudinal axis in the direction of motion of the body 1 and is configured in the shape of a rectangle in its cross section. The cross section of the friction rail 2 could also exhibit a different profile, even the profile of a circle or a circular ring. After the body 1 has driven into the device, the friction rail 2 is moved between two opposite brake shoes 3, 3' of two upwards oriented brake calipers, which during a subsequent braking action arrive with their brake linings in frictional engagement at the friction surface of the friction rail 2. The application force of the brake linings and, thus, the braking force is controlled by a control unit in such a manner that almost complete conformity between the actual motion and the desired motion of the body 1 is achieved.

In order to be able to consider realistically also the influence, which is induced by the elasticity of the test body in the crash test and which accelerates rearwards the body 1 after its plastic deformation, a rearward acceleration device is provided. This rearward acceleration device consists of a force transfer device, which is connected to the control unit, and a carriage 7, which is guided by rotatable rollers 4 and can be moved between stops 5, 6 approximately linearly in the direction of motion of the body 1. Furthermore, the two brake calipers are mounted on the upper side of said carriage. In this embodiment U-shaped rails 8, 8' are mounted laterally of the carriage 7. The longitudinal axis of said rails extends approximately in the direction of motion of the body 1. Spaced apart from each other, the rails 8, 8' envelop with their legs the sides of the carriage 7. In the free spaces between the legs of the rails 8, 8' and the associated opposite upper and lower sides of the carriage 7 as well as between each land of the rails 8, 8' and the sides of the carriage 7 there is mounted in the front and the rear area of the carriage 7 a rotatable roller 4 for guiding the carriage 7 with almost no clearance. In this case the axes of rotation of the rollers 4 are oriented in such a manner that the result in each case is a rotation of the rollers 4 that is in conformity with the motion of the carriage 7. However, the number of rollers 4 and their arrangement could also be selected, for example, so as to deviate from the embodiment. The stops 5, 6, which are provided to limit the motion of the carriage, are mounted on the lands of the rails 8, 8'. As long as the body 1 drives into the device in the forward direction, the carriage 7 rests at the stop 6, which is located in the forward direction.

Figure 2 is a front view of the device, of which Figure 1 is a principle sketch. Figure 2 shows additional details, in particular the arrangement of the rollers 4; the brake rail 2, which is connected to the body 1; and the brake shoes 3, 3', which are mounted on the upper side of the carriage 7.

Figure 3 shows the device in Figure 1 with the body 1 almost completely braked in its forward motion, just before its rearward acceleration.

After the body 1 has terminated its forward motion, the brake calipers are drawn together so tightly that a rigid connection is produced between the friction rail 2 of the body 1 and the carriage 7, connected to the brake calipers.

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Then a controlled acceleration or braking force is exerted on the carriage 7 by means of the force transfer device in such a manner that the result is the desired motion sequence of the body 1. The illustrated embodiment is equipped with a hydraulically operating force transfer device, which is indicated by a symbolized hydraulic cylinder 9. Not until the body 1 comes to a standstill, as shown in Figure 4, are the brake calipers released; and the body 1 can be driven out of the device again. The distance between the stops 5, 6 is dimensioned in such a manner that the carriage 7 is prevented from starting up prematurely during the test run. In order to detect the state of motion 1 during its forward and rearward motion, there is an acceleration sensor, which is used for controlling the braking force and rearward acceleration force.

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1 sheet of drawings

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- Blank Sheet -

Drawings Sheet 1

Number: 34 21 546

Int. Cl⁴ : G 01 M 7/00

Date of publication: November 14, 1985