JPS6215779B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides a flexible elastomer sealing boot ( boot).

Disc brake boots or dirt seals are known and used in the automotive sector.
However, the known type of elastomeric rubber boot commonly used is a boot with a uniformly thin flexible wall, which is formed into an accordion pleated or bellows configuration and then used in a litter boot assembly. The cylinder is elongated into an elongated configuration, with one end retained within the cylinder bore recess and the other end retained within the piston recess. To save space and weight, the piston-to-bore annular spacing should be as narrow as possible. For example, the outer diameter of the piston is 45 mm, and the inner diameter of the recess or bore of the cylinder that holds the boot is 58.3 mm. Also, the boot must be able to extend approximately 30mm and when the piston is retracted to change brake pads approximately 11.5mm
Must be retracted to a total height of mm. This narrow annular space between the retaining wall of the bore and the piston makes it very difficult to mold a bellows-shaped boot with an accordion convolution with a sharp bend. The convolution is necessary so that upon retraction of the piston, the normal boot flexes and rolls into the annular space. Due to the sharp bends in the bellows walls of prior art boots, the boot has an uneven and jerky motion during retraction and extension. A conventional swivel boot with a bellows-shaped sleeve was developed, for example, in 1976.
Kondo's U.S. Patent No. Granted Dec. 21
It is disclosed in No. 3998466.

In accordance with the present invention, an improved sealing boot for use in an annular space between a cylinder and a piston of a disc brake assembly is provided with a non-convoluted shape consisting of a plurality of separate sections having a plurality of different wall thicknesses on an annular metal reinforcing shell. having a sleeve;
Provided by molding a one-piece, elongated, flexible, elastomeric sealing boot.
Preferably, seven separate sleeve sections are used which cooperate to form a sealing boot when installed within the disc brake assembly, which sealing boot can be used to replace disc brake pads. When the piston is retracted into the cylinder of the brake assembly, it can flex into a convoluted shape that fits within the annular space between the piston and the cylinder. The elongated, non-convoluted shape of this sleeve is a molding advantage compared to the uniformly thin convoluted shape of conventional bellows-shaped sleeves, which is difficult to mold. Furthermore, the sealing boot of the present invention is at least as effective as prior art seals for sealing the piston from dirt and water in a known manner. Additionally, the novel sealing boot of this invention contracts and expands smoothly, where the different thicknesses of each wall section enhance the deflection and curling effect of the boot when the boot is contracted into a convoluted shape and stretched into a stretched shape. Provides a flexible sleeve portion.

The invention will be better understood from the following detailed description taken in conjunction with the accompanying drawings.

Referring now to FIG. 1, a prior art sealing boot 2 consists of a thin-walled bellows-shaped convoluted elastomeric sleeve 4 molded in a convoluted configuration over a metal reinforcing shell 6. As shown in FIG. In use, the flexible bellows stretches and the elastomer of the bellows is under tension during actuation of the piston.

Referring now to Figures 2, 3 and 4, there is shown a disc brake sealing boot 8 according to the present invention. Sealing boot 8 includes an integrally molded, elongated, flexible elastomer sleeve 10
and an annular metal reinforcing shell 18 to which an elastomeric sleeve 10 is coupled. As shown in FIG. 4, sealing boot 8 is formed as a single unit having a cylindrical outer surface 9 that frictionally fits within bore 21 of cylinder 20 adjacent piston 19. As shown in FIG.

The elastomeric sleeve 10 cooperates to seal the space between the piston 19 and the cylinder 20 to prevent dirt and water from entering the piston sliding area 7
It consists of two separate parts. The seven parts of the sleeve are particularly designed so that the elongated sleeve flexes and curls to form an annular space 2 between the piston 19 and the bore 21.
2 cooperates so that it can be folded into a convoluted shape that fits within the 2.

The seven sections of the elastomeric sleeve are clearly shown in FIG. The elastomer from which the seal is made may be any type of elastomer that is at least flexible between the upper and lower extremes of the temperature conditions in which the disc brake assembly is to be used. The elastomer should also be resistant to brake fluid, road salt, water and other expected contaminants. Generally, elastomers used to make prior art bellows-shaped elastomers, such as rubber and synthetic elastomers, can be used to mold the boot of the present invention by known molding methods such as injection molding or compression molding.

Referring to FIG. 2, elastomeric sleeve 10
includes as its first part a sealing bead portion 11 at the piston sealing end of the sleeve.
This bead portion 11 is adapted to fit elastically into an annular recess 23 in the periphery of the piston wall, adjacent to the axially extending outer end wall 24 of the piston 19 . The bead portion 11 has an inner diameter that is sufficiently smaller than the outer diameter of the piston, such that the bead is elastically stretched to fit into the recess 23 and form a seal therewith. Elastomeric sleeve 10 includes as its second portion an upper boot wall portion 12 having a substantially uniform wall thickness and integrally molded with bead portion 11 and at an oblique angle to the plane of the bead portion. and a bead-adjacent end extending radially outwardly. wall part 12
connects its radially outermost end to the upper flexible wall portion 13
It is integrally molded on the upper end of the third portion of the sleeve 10. Upper deflection wall part 1
3 has a lower end integrally molded with the upper end of the fourth part of said sleeve 10, which is the stabilizing wall part 14.

Stabilizing wall section 14 has a substantially uniformly thick wall with a thickness greater than the wall thickness of upper boot wall section 12 and a length greater than the length of said upper boot wall section 12 . The upper flexible wall section 13 has a thinner wall thickness than that of the upper boot wall section 12 or the stabilizing wall section 14. The stabilizing wall section 14 has an inner wall diameter that is larger than the outer diameter of the piston 19 but smaller than that of the cylinder sealing end section 17, which will be described below. The walls of wall portion 14 extend axially parallel to the cylindrical wall of metal shell 18 to which sleeve 10 is connected.

Upper boot wall section 12 is arranged with its walls at an acute angle to the walls of wall section 14. Upper flexible wall section 13 is curved and forms a connecting wall between adjacent ends of wall sections 12,14.

The elastomeric sleeve 10 includes as its fifth portion an outwardly flared frusto-conical rounded wall section 15 which includes an upper end and a lower flexure-rounded wall section 1 integrally molded to the lower end of said wall section 14.
6, having a lower end integrally molded into the sixth portion of said sleeve 10. wall part 16
has a wall of substantially uniform thickness having an inner diameter greater than the inner diameter of stabilizing wall portion 14 and less than a wall thickness of wall portion 14 . The frusto-conical rolling wall section 15 has a length approximately equal to or less than the length of the stabilizing wall section 14 and the rounded wall section 16 is shorter than the wall length of the frusto-conical rounded wall 15. It has wall length. The lower end of the rounded wall section 16 is integrally molded with the upper end of the seventh section of the elastomeric sleeve 10, which is the cylinder sealing end section 17.

Wall section 16 and cylinder sealing end section 1
The inner diameter of 7 is sufficiently larger than the diameter of piston 19 so that sealing boot 8 is installed within the disc brake assembly and piston 19 is inserted into cylinder 20, as is done when disc brake pads are to be installed or replaced. When retracted, it creates an annular space suitable for accommodating the stabilizing wall section 14 and the wall section 15 in a deflected and pivoted position.

FIG. 4 shows that when the piston 19 is retracted into the cylinder 20, the elastomer sleeve 10
3 and wall sections 14 and 15, wall section 15
and 16 show the curling and deflection at the adjacent ends of wall portion 16 and cylinder sealing end portion 17, respectively. When the piston 19 reaches its fully extended position, the sealing bead portion 11 of the seal
In the position shown, the bead is in the recess 23, the wall portion 12 is extended radially outward, and the wall portion 13 is deflected from the acute angle position shown in FIG. 2 to the obtuse angle position shown in FIG.

During piston retraction, the functions of the various parts of the elastomeric sleeve are generally as follows.

The upper boot wall section 12 is connected to the upper flexible wall section 13
exerts a downward and outward force on the This force is resisted by the stabilizing wall section 14, which causes the sealing bead section to roll within the recess 23, causing the upper boot wall section 12 to invert and assume the position shown in FIG.
Similarly, the flared frusto-conical rounded wall section 15 exerts a downwardly outward force on the lower flexural rounded wall section 16, which causes the wall section 16 to deflect outwardly;
The wall portion 15 is curled up into a position as shown in FIG. Finally, the retraction of the piston causes the stabilizing wall section 14 to act on the lower deflecting and curling wall section 16 via the reversed wall section 15 with a downward force. This step causes the wall section 16 to curl up and fold into the pivoted position shown in FIG. Wall sections 12 and 15
The reversal steps are independent and can occur simultaneously or one after the other.

As those skilled in the art will appreciate, as the brake disc pad wears, the sealing boot gradually moves from the configuration of FIG. 4 to the configuration of FIG. 3. At this time, when the worn pad is replaced, the sealing pad returns to the configuration shown in FIG. 4 and the cycle repeats.

Although the invention has been described in detail with particular reference to preferred embodiments thereof, it will be understood that many changes and modifications may be made within the spirit and scope of the invention as hereinbefore described and defined in the claims. Should.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of a prior art disc brake sealing boot. FIG. 2 is a partial cross-sectional view of a disc brake sealing boot according to the present invention. FIG. 3 is a partial cross-sectional view of a disc brake piston showing one end of the sealing boot of the present invention in an extended position and retained within a recess in the piston. FIG. 4 is a partial cross-sectional view of the piston, cylinder, and sealing boot of the present invention showing the sealing boot in a collapsed position when the piston is in a retracted position within the cylinder. 2...Prior art sealing boot, 4...Elastomer sleeve, 6...Metal reinforcement shell, 8...
Sealing boot of the present invention, 9... Cylindrical outer surface,
10... Elastomer sleeve, 11... Sealing bead portion, 12, 13, 14, 15, 16,
17...Wall part, 18...Metal reinforcement shell, 19
... Piston, 20 ... Cylinder, 21 ... Bore, 22 ... Annular space, 23 ... Recess, 24
...end wall.

Claims (1)

Claims: 1. A flexible elongated sealing boot sealing an annular space between a cylinder wall defining a bore and a piston movable axially relative to the cylinder wall within said bore, the sealing boot comprising: includes an annular molded one-piece elastomeric sleeve that is foldable from an extended, as-formed condition into a collapsed, convoluted configuration, the sleeve having a sealing bead at one end thereof and a cylinder sealing end at the other end. the bead portion has a smaller as-molded inner diameter than the cylinder sealing end, and the sleeve includes a plurality of seven separate wall portions of different thicknesses connected together in series; successively from said bead portion side a sealing bead portion, an upper boot wall, an upper flexural wall, a stabilizing wall, an outwardly flared frusto-conical rounded wall, a lower flexural rounded wall, and a cylinder sealing end; The upper boot wall with beaded portion is radially inwardly from the stabilizing wall when the sleeve is in the as-molded form and is joined to the stabilizing wall by the upper flexible wall, and the cylinder sealing an edged lower flexible radius wall is radially outwardly from the stabilizing wall when the sleeve is in the as-molded configuration and is joined to the stabilizing wall by the outwardly flared frustoconical radius wall; A flexible elongated sealing boot characterized by: 2. The flexible elongated sealing boot of claim 1, wherein the upper boot wall is shaped at an acute angle with the stabilizing wall. 3. A flexible elongated sealing boot according to claim 2, wherein the cylinder sealing end has an external cylindrical surface and the stabilizing wall is cylindrical and of substantially uniform thickness. 4. The upper boot wall is of substantially uniform wall thickness that is thinner than the stabilizing wall, and the upper flexible wall is a curved connecting wall between the upper boot wall and the stabilizing wall. A flexible elongated sealing boot according to clause 3. 5. said lower flexible rounded wall has an inner diameter greater than the inner diameter of said stabilizing wall and has a substantially uniform thickness thinner than said stabilizing wall, said frusto-conical wall having a length less than said stabilizing wall; Short claim number 4
Flexible extension sealing boot as described in Section 1. 6. The flexible elongated sealing boot of claim 5, wherein the inner diameters of the lower flexible rounded wall and the cylinder sealing end are substantially the same. 7. The flexible elongated sealing boot of claim 1, wherein the cylinder sealing end comprises an annular metal shell overlying an annular elastomer layer.