WO1992001169A1 - Silencer for disc and drum brakes - Google Patents

Abstract

The invention addresses the problem of reducing brake noise, in particular squeaking, in disc or drum brakes. The aim of the invention is to make available a particularly effective and reliable device for silencing brake noise. This is achieved by means of at least one fixed silencer (5, 6) which is in frictional contact with the rotating brake disc (1) or drum and damps the disc or drum vibrations. The invention differs from prior art devices by its versatility. It is not restricted to a particular type of brake and permits individual optimization of the silencing characteristics. The silencer (7) is preferably used for the silencing of fixed brake components. In a further embodiment of the invention, a spring (113) carrying a small mass (115) is attached to the brake housing, and presses this mass (115) against the brake.

Description

Muffler for disc or drum brakes

The invention is based on a disc or drum brake and relates to the problem of suppressing noise emanating from the brake, in particular squeaking.

It is proven that braking noises result from vibrations of the brake housing, the brake shoes or the brake disk or brake drum, which are excited due to periodic fluctuations in the frictional force between the brake shoes and brake disk or brake drum.

Brake squeaking is particularly uncomfortable. For this reason, numerous measures have been proposed and some have been put into practice which are intended to prevent disturbing noise from the brake, either by damping oscillating brake parts or by detuning their natural frequencies so that they lie in the inaudible range or are no longer excited.

For example, it is known to dampen the vibrations of the brake pads in disc brakes by providing a rubbing insert between the brake piston and the pad holding plate of a brake shoe (DE-GM 87 17 512) or that on the side of the pad holding plate facing the brake piston viscoelastic insulation board (DE-OS 23 05 701), a polymer layer (DE-OS 28 11 848) or a damping plate is used.

To date, however, the problem of braking noise has not yet been satisfactorily resolved. Known measures prevent squeaking only temporarily or only with a certain type of brake. Since no systematic solution method is known, successful measures are found primarily through trial and error and are usually limited to the individual case.

The aim of the invention is therefore to tackle the problem of suppressing braking noises somewhat more systematically and to find a generally usable, effective and reliable solution.

The starting point of the solution is the observation that particularly large oscillation amplitudes (antinodes) occur at certain points on the brake, especially on the brake disc or brake drum, which cause loud braking noises and can therefore be combated most effectively here.

The object is achieved by the combination of features resulting from the characterizing part of the main claim or from one of the subordinate claims 9 and 10.

The noise damping takes place on the friction surface of the noise damper, which is constantly in contact with the brake, in that vibration energy is converted into frictional heat.

An advantage is the versatility of the invention, which is not limited to a particular type of brake, but can be used both in disc and drum brakes of various types. Compared to known devices, it is characterized by the consequence of also applying vibrations to rotating parts of the brake. dampen where they occur preferentially. If the circumstances so require, several silencers can be used.

In a preferred embodiment according to claim 2, the noise damper is adjustable. In this way, its friction surface can be set to a point of maximum vibration amplitude and its effectiveness can be individually optimized. If the properties of the brake change over time, the process can be repeated.

According to claim 3 can be advantageously used that large areas of the brake disc or brake drum are easily accessible. The point to be damped can be selected relatively freely according to practicality, without the noise damper and other brake parts interfering with one another. In this way, its effectiveness is further increased and remains more reliably maintained, which is particularly important in stubborn cases of brake squeal.

It is expedient if the noise damper according to claim 4 has a resilient element which generates the force for pressing its friction surface against the brake.

If, according to claim 5, the pressing force is adjustable, further possibilities open up for individually optimizing the damping at any time.

If the circumstances require that the friction surface should be pressed on with great force, without the friction force and permissible increase, the embodiment according to claim 6, in which the friction surface is made of metal, is advantageous.

However, if the pressure force is to be small or the friction force is large, an embodiment according to claim 7 is more favorable in which the friction surface has a friction lining.

The invention can be further improved if the noise damper according to claim 8 is anchored to a vehicle part to which essentially no vibrations of the brake are transmitted which could impair the effectiveness of the damping.

In addition to rotating, the noise damper can also be advantageously used on stationary brake parts that tend to vibrate, for example according to claim 9 on the brake caliper of a disc brake.

If the effort required to attach the muffler outside the brake is to be avoided, sic recommends an embodiment according to claim 10. The muffler is attached directly to the brake here, so that the muffled brake can be installed as a pre-assembled unit on the vehicle. An additional dimension rests resiliently on the brake housing and, due to its inertia, enables a rubbing relative movement between the contact surface of the silencer and the brake housing.

In a preferred embodiment of the invention according to Claim 11, the silencer is attached to a guide pin of a floating caliper partial brake disc brake. This attachment only requires a modified guide pin, while the brake housing of a current series can otherwise be taken over unchanged. This saves tool costs. It is also possible to retrofit conventional brakes with the noise damper according to the invention. Further advantageous design features are disclosed in subclaims 12 and 13.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings.

Show it

1 is a side view of a schematically shown disc brake with silencers,

2 shows a section through a schematically illustrated drum brake with noise dampers,

Fig. 3 is a partially sectioned side view of a floating caliper brake pad with a noise damper according to the invention in a further embodiment.

The first example relates to a disc brake, the essential components, namely brake disc 1, brake shoes 2, 3 and brake caliper 4 in FIG. 1 schematically are shown.

In order to illustrate the possible uses for silencers 5, 6, 7, three different friction points are provided which are easily accessible.

The silencers 5 and 6 consist of friction lining 8, leaf spring 9 and anchoring 10, by means of which they are connected to the wheel suspension of the vehicle.

The friction lining 8 is positioned so that it presses against a point on the brake disc 1 that tends to large vibration amplitudes and suppresses them. Due to its position, noise damper 5 is particularly well suited for damping axial, noise damper 6 for damping radial or tangential vibrations of brake disc 1.

In the case of noise damper 7, the friction surface 11 is made of steel and is simply formed by the free end of the leaf spring 12. Its anchor 13 is also connected to the wheel suspension. The friction surface 11 presses on a point of the brake caliper at which large vibration amplitudes occur, which are damped in this way.

In the second example, the application of the invention to a drum brake is explained, the drum 14 and brake shoes 15.16 of which are indicated in section in FIG. 2. The construction of the silencers 17, 18, 19 was already described in the first example. The noise dampers 17, 18, 19 are also used here at three easily accessible friction points, which tend to large vibration amplitudes. It is attached to the brake carrier of the drum brake.

In the exemplary embodiment shown in FIG. 3, a partial lining disk brake has a floating caliper 101 with a brake piston 102 and two brake shoes 103, 104, which are intended to be pressed against a brake disk 105. The floating caliper 101 is slidably guided on a brake carrier 106 by means of two bolt guides. One of the two bolt guides can be seen in the drawing. A thread 108 of a guide bolt 109 is screwed into a threaded bore 107 of the brake carrier 106, on which a bushing eye 110 connected to the floating caliper 101, which is provided with a bushing 111 made of elastic material, slides.

The guide pin 109 is provided on its end section facing away from the brake carrier 106 with a circumferential annular groove 112, in which the one end 117 of a wire spring 113 belonging to a noise damper 114 is clamped. The silencer 114 also includes an additional mass 115 with a cylindrical base body which merges into a cone 119 on one axial side and has a cylindrical projection 116 on its other axial side, around which the other end 118 of the torsion spring 113 is wound. The guide pin 109 has an axial opening 120 with hexagonal in its end portion Cross-section that was originally intended to hold a wrench. The additional mass 115 is now pressed axially against the end of the guide bolt 109 by means of the spring 113, so that the tip of the cone 119 extends into the opening 120 and the cone jacket lies against the outer edge of the opening 120. This simple fastening allows, on the one hand, relative movements between the brake and additional mass 115 and, on the other hand, prevents the additional mass 115 from falling out.

Claims

Claims 1. Noise damper (5, 6, 17, 18, 19) for discs or drum brakes, characterized in that the rotating brake disc (1) or brake drum (14) is damped by pressing on a stationary damping means (8) rubbing against it . 2. Muffler (5, 6, 17, 18, 19) according to claim 1, so that the location on the brake disc or brake drum at which the damping means (8) acts rubbing is adjustable. 3. Muffler (5,6,17,18,19) according to claim 1 or 2, characterized in that the damping means (8) at an accessible location, preferably on the side of the brake disc (1) or brake drum facing away from the vehicle wheel (14) attacks, which has large vibration amplitudes (antinodes). 4. Noise damper (5, 6, 17, 18, 19) according to one of the preceding claims, characterized in that it has a resilient element (9), preferably a wire or leaf spring, one of whose ends de connected to a friction surface (8) and the other end of which is anchored to the vehicle. 5. A silencer (5, 6, 17, 18, 19) according to one of the preceding claims, characterized in that its pressing force is adjustable. 6. A silencer (5, 6, 17, 18, 19) according to one of the preceding claims, characterized in that the friction surface (8) made of metal, which rests on the brake disc (1) or Bremstrom¬ mel (14), preferably consists of steel. 7. Noise damper (5, 6, 17, 18, 19) according to one of claims 1 to 6, characterized in that the friction surface (8) bearing on the brake disc (1) or brake drum (14) has a friction lining ¬ is preferably seen of the type used for brake pads. 8. A silencer (5, 6, 17, 18, 19) according to one of the preceding claims, characterized in that it is anchored to a vehicle part, preferably the wheel suspension, on which vibrations causing no braking noise occur to step. 9. muffler (7) for disc brake, characterized ge ¬ indicates that it is anchored outside the brake caliper (4), a resilient element (12), preferably has a wire or leaf spring and presses by means of a preferably metallic friction surface (11) or a friction lining against a location of the brake caliper (4) at which large oscillation amplitudes occur. 10. Noise damper for disc brakes, characterized in that a resilient element, preferably a leaf or wire spring (113) is anchored to the brake housing, which carries a small additional mass (115) and presses it onto the brake. 11. A silencer according to claim 10 for a floating caliper partial brake disc brake, in which a floating caliper is slidably mounted on a fixed brake carrier by means of a pin guide, characterized in that the resilient element (113) on an end section of the floating caliper (101) of a guide bolt protrudes (109) is fixed and that the additional mass (115) is pressed onto the same end section, preferably in the axial direction. 12. A silencer according to claim 11, characterized ¬ indicates that the guide pin (109) is provided at its end portion with a circumferential annular groove (112) and that the resilient element is a wire spring (113) which engages in the annular groove (112) is clamped on the guide pin (109). 13. A silencer according to claim 11 or 12, characterized in that the guide pin (109) in its end portion has an axial recess (120), preferably a bore or a hexagonal opening (120) in cross section, that the additional mass (115) substantially has the shape of a cylinder with an attached cone (119), the cylinder diameter corresponding approximately to the diameter of the guide pin (109) and that the additional mass (115) is pressed axially against the end portion of the guide pin (109) so that the tip of the Cone (119) is located within the recess (120) and the cone jacket lies against the outer edge of the recess (120).