Caliper disc brake of a vehicle, in particular a commercial vehicle, and holding-down spring of such a brake

1. A caliper disc brake of a vehicle, with

a brake disc having an axis of rotation (A),

a brake caliper ( 20 ),

a brake support plate ( 22 ),

a force transmission element, which is guided and supported in a well of the brake caliper or of the brake support plate,

a holding-down spring ( 30 , 32 , 34 ) for holding down the force transmission element, and

a holding-down device ( 36 ), which

is held and supported on the caliper by a holding device ( 38 , 40 ),

preloads the holding-down spring radially against the force transmission device, and

preloads the holding-down spring tangentially in the direction of rotation (D) against the force transmission device during forward travel,

wherein the holding-down device has a center line (M) parallel to the axis of rotation,

wherein the holding-down spring ( 30 , 32 , 34 ) has two identical spring legs ( 76 , 78 ) and a trapezoidal central region ( 80 ),

wherein the holding-down device ( 36 ) rests on the holding-down spring ( 30 , 32 , 34 ) in a bead-shaped first region ( 74 ) that produces the radial preload and rests on the holding-down spring in a second region ( 82 ) that produces the tangential preload, and the distance between a central point (M 74 ) of the first region and a central point (M 82 ) of the second region is smaller in a radial direction than in a tangential direction (H<E).

2. The caliper disc brake as claimed in claim 1 , wherein the trapezoidal central region has a base between two trapeze legs and in the relaxed state, the holding-down spring ( 30 , 32 , 34 ) in each case extends in an arc with a radius (R 1 ) of 10 mm to 16 mm in a transitional region between the two trapeze legs of the trapezoidal central region and the base thereof and in an arc with a radius (R 2 ) of 4 mm to 9.5 mm in the transitional region between the trapezoidal region and the spring legs ( 76 , 78 ).

3. The caliper disc brake as claimed in claim 1 , wherein the holding-down spring is symmetrical and, owing to the symmetry, is adapted to be installed in two installation positions rotated by 180° relative to one another.

4. The caliper disc brake as claimed in claim 1 , wherein the holding-down spring ( 30 , 32 , 34 ) is a leaf spring.

5. A holding-down spring of a caliper disc brake of a vehicle, having two identical spring legs ( 76 , 78 ) and a trapezoidal central region ( 80 ) with two trapeze legs and a base, which is located between the two spring legs and projects radially inward, wherein the two trapeze legs of the trapezoidal region each enclose an angle (α) of more than 95° with the base in a relaxed state and an angle (β) of less than 85° with a respectively adjacent one of the two spring legs in a location where each of the trapeze legs meets the respectively adjacent one of the two spring legs.

6. The holding-down spring as claimed in claim 5 , wherein in the relaxed state, the holding-down spring extends on each of two opposite sides in an arc with a radius (R 1 ) of 10 mm to 16 mm in a transitional region between the two spring legs of the trapezoidal region and the base and in an arc with a radius (R 2 ) of 4 mm to 9.5 mm in a transitional region between the trapezoidal region and the spring legs ( 76 , 78 ).

7. The holding-down spring as claimed in claim 5 , wherein the holding-down spring is symmetrical and, owing to the symmetry, is adapted to be installed in two installation positions rotated by 180° relative to one another.

8. The holding-down spring as claimed in claim 5 , wherein the holding-down spring is a leaf spring.