Fixed caliper disk brake having stabilized brake pads, and related assembly and pad replacement methods

1. A fixed caliper ( 10 ) motor vehicle disk brake comprising:

a disk,

a caliper casing ( 11 ) that straddles the disk,

at least one brake pad ( 12 ) that is adapted to co-operate with a facing lateral face of the disk, and

at least one piston ( 8 ) that is mounted to slide axially in a complementary cylinder ( 7 ) of the caliper casing and that co-operates with said brake pad ( 12 ) to urge it axially in the direction of said lateral face of the brake disk,

and wherein:

a) the caliper casing ( 11 ) comprises two opposite blocks ( 14 ), respectively at the front and at the rear, each of which comprises:

a C-section axial housing ( 16 ), open horizontally in a direction of the opposite block ( 14 ), that is delimited by an upper face ( 32 ) and by a lower face ( 34 ) of horizontal general orientation;

an axial bearing surface ( 20 ) of vertical (V) general orientation below the C-section axial housing ( 16 );

b) the brake pad ( 12 ) comprises:

two opposite lateral mounting lugs ( 26 ) each of which is received in an associated housing ( 16 ) of an associated block ( 14 ) of the casing ( 11 ) of the caliper and each of which is delimited by an upper facet ( 36 ) of horizontal general orientation;

associated with each lug ( 26 ), a vertically oriented lower facet ( 38 ) below the associated lateral lug ( 26 );

c) said fixed caliper ( 10 ) further comprises means ( 40 , 22 ) for mounting and guiding axial sliding of the brake pad relative to the fixed casing comprising:

i) for each lug ( 26 ) of the brake pad ( 12 ), a pad spring ( 40 ) that is fixed to the associated lug ( 26 ) of the brake pad ( 12 ) and comprises at least one lower sliding branch ( 42 ) that co-operates with the lower face ( 34 ) of the associated housing ( 16 ) and urges said upper facet ( 36 ) of the lug ( 26 ) vertically upward to bear against the upper face ( 32 ) of the associated housing ( 16 );

ii) for each block ( 14 ) of the caliper casing ( 11 ), a spring steel lamellar element ( 22 ) which comprises at least:

a C-section upper axial sliding part ( 52 ) that is received in and locked into the associated housing ( 16 ), that comprises a first, lower flange ( 24 ), referred to as the sliding flange, of substantially horizontal general orientation, that is disposed between the sliding branch ( 42 ) of the pad spring ( 40 ) and the lower face ( 34 ) of the housing ( 16 ) of the caliper ( 11 ), and a second, upper flange ( 25 ), referred to as the vertical bearing flange, of horizontal general orientation, that is disposed between the upper facet ( 36 ) of the associated lug ( 26 ) of the brake pad ( 12 ) and the upper face ( 32 ) of the associated housing ( 12 ); and

at least one axial bearing lower part ( 54 ) comprising a third flange ( 28 ), referred to as the transverse bearing flange, that extends the sliding flange ( 24 ), that extends in a plane orthogonal to the plane of the sliding flange ( 24 ), that is arranged in contact with the transverse bearing surface ( 20 ) of the associated block ( 14 ), and that is adapted to form a transverse abutment for the associated lower facet ( 38 ) of the brake pad ( 12 ).

2. The fixed caliper disk brake as claimed in claim 1 , wherein the lamellar element ( 22 ) is elastically deformable between:

an initial state, prior to mounting in the housing ( 16 ) of the lug ( 26 ) of the brake pad ( 12 ) fitted with its pad spring ( 40 ), in which the sliding flange ( 24 ) forms with the plane of the lower face ( 34 ) of the housing ( 16 ) a first acute angle (α),

at least one loaded state after mounting in the housing ( 16 ) of the lug ( 26 ) the brake pad ( 12 ) fitted with its pad spring ( 40 ), in which the sliding flange ( 24 ) forms with the plane of the lower face ( 34 ) of the housing ( 16 ) a zero angle or a second acute angle (β) the value of which is less than that of the first acute angle (α), and in which said sliding branch ( 42 ) of the pad spring ( 40 ) is elastically prestressed.

3. The disk brake as claimed in claim 2 , wherein the sliding flange ( 24 ) comprises an anchor tongue ( 56 ) that projects downward and co-operates with the lower face ( 34 ) of the housing ( 16 ) so as to be anchored in this lower face ( 34 ) and to lock the upper part ( 52 ) in the position mounted in the associated housing ( 16 ).

4. The disk brake as claimed in claim 3 , wherein the lower face ( 34 ) of the housing ( 16 ) comprises a recess ( 37 ) in which the anchor tongue ( 56 ) is received with no clearance in the axial direction so as to immobilize the lamellar element ( 22 ) axially relative to the block ( 14 ).

5. The disk brake as claimed in claim 4 , wherein the lamellar element ( 22 ) comprises an axial immobilization part ( 58 ) that extends upward the vertical second bearing flange ( 25 ) that co-operates with a complementary part ( 60 ) of the block ( 14 ) so as to immobilize the lamellar element ( 22 ) axially relative to the block ( 14 ).

6. The disk brake as claimed in claim 5 , wherein an edge ( 66 ) of the sliding flange ( 24 ) connecting it with the transverse bearing flange ( 28 ) comprises at least one axial cut-out ( 68 ).

7. The disk brake as claimed in claim 6 , wherein the lamellar element ( 22 ) is of symmetrical design with respect to a vertical median transverse plane.

8. The disk brake as claimed in claim 7 , wherein each pad spring ( 40 ) comprises at least one curved branch ( 48 ) that extends in the axial direction and that connects its sliding branch ( 42 ) to a branch ( 46 ) of the brake pad for fixing it to the lug ( 12 ) of the brake pad.

9. A method of assembling a disk brake as claimed in claim 8 , further comprising:

a first step during which the lamellar elements ( 22 ) are locked into the associated housings ( 16 ) of the blocks ( 14 ) of the caliper ( 11 ),

a second step during which the pad springs ( 40 ) are fixed to the brake pad ( 12 ), the curved branches ( 48 ) being arranged on the same side of the brake pad ( 12 ),

a third step during which the brake pad ( 12 ) equipped with its two pad springs ( 40 ) is introduced into the housings ( 16 ) of the blocks ( 14 ) of the caliper ( 11 ) so that the curved branches ( 48 ) of the pad springs ( 40 ) enter first so that said branches of said pad springs ( 40 ) load the associated lamellar elements ( 22 ) and spread apart the first, lower sliding flanges ( 24 ) and the vertical second bearing flanges ( 25 ).

10. A method of replacing a brake pad of a disk brake as claimed in claim 8 , further comprising:

a first step during which the curved branches ( 48 ) of the pad springs ( 40 ) are compressed,

a second step during which the brake pad ( 12 ) fitted with its pad springs ( 40 ) is extracted from the housings ( 16 ) of the blocks ( 14 ) of the caliper ( 11 ),

a third step during which a new brake pad ( 12 ) is introduced the lugs ( 26 ) of which are equipped with two pad springs ( 40 ) in the housings ( 16 ) of the blocks ( 14 ) of the caliper so that the curved branches ( 48 ) of the pad springs ( 14 ) enter first so that said branches ( 48 ) of said pad springs ( 40 ) load the lamellar elements ( 22 ) and move the first, lower sliding flanges ( 24 ) away from the vertical second bearing flanges ( 25 ).

11. The disk brake as claimed in claim 2 , wherein the lamellar element ( 22 ) comprises an axial immobilization part ( 58 ) that extends upward the vertical second bearing flange ( 25 ) that co-operates with a complementary part ( 60 ) of the block ( 14 ) so as to immobilize the lamellar element ( 22 ) axially relative to the block ( 14 ).

12. The disk brake as claimed in claim 2 , wherein the lamellar element ( 22 ) is of symmetrical design with respect to a vertical median transverse plane.

13. The disk brake as claimed in claim 2 , wherein each pad spring ( 40 ) comprises at least one curved branch ( 48 ) that extends in the axial direction and that connects its sliding branch ( 42 ) to a branch ( 46 ) of the brake pad for fixing it to the lug ( 12 ) of the brake pad.

14. The disk brake as claimed in claim 1 , wherein the caliper casing ( 11 ) comprises two half-casings each of which is delimited by a junction face ( 13 ) of vertical and transverse orientation and the two half-casings are fixed to each other by a series of axial fixing screws ( 80 ).

15. The disk brake according claim 14 , wherein the caliper casing ( 11 ) and the means for mounting and guiding the brake pads are of generally symmetrical design with respect to said junction face ( 13 ).

16. The disk brake as claimed in claim 1 , wherein the lamellar element ( 22 ) comprises an axial immobilization part ( 58 ) that extends upward the vertical second bearing flange ( 25 ) that co-operates with a complementary part ( 60 ) of the block ( 14 ) so as to immobilize the lamellar element ( 22 ) axially relative to the block ( 14 ).

17. The disk brake as claimed in claim 1 , wherein an edge ( 66 ) of the sliding flange ( 24 ) connecting it with the transverse bearing flange ( 28 ) comprises at least one axial cut-out ( 68 ).

18. The disk brake as claimed in claim 1 , wherein the lamellar element ( 22 ) is of symmetrical design with respect to a vertical median transverse plane.

19. The disk brake as claimed in claim 1 , wherein each pad spring ( 40 ) comprises at least one curved branch ( 48 ) that extends in the axial direction and that connects its sliding branch ( 42 ) to a branch ( 46 ) of the brake pad for fixing it to the lug ( 12 ) of the brake pad.