JP4240302B2 - How to install the disc brake pad - Google Patents

Description

    The present invention relates to a disc brake that brakes by pressing brake pads (friction materials) on both surfaces of a rotating disk used in a brake device of an automobile, and in particular, when a brake pad that presses against the disc and generates a braking force is attached to a backing plate. Concerning the method.

The structure of the disc brake of an automobile can be known from a developed view showing the basic structure by referring to JIS D-0107. A disc brake is a brake device that presses and brakes friction material against the rotating surface of a rotating disc. The friction material that presses against both sides of the disc to generate braking force is called a brake pad. and a friction material such as (non-patent document 1).

  In the conventional brake pad manufacturing method, brake pad material powder prepared from dozens of inorganic and organic materials is lightly pressed into a biscuit shape to prevent pre-molding. Let it harden. On the other hand, after degreasing the surface of the backing plate (metal back plate) with a plurality of mounting holes, heat-resistant adhesive is applied. In the next molding process, set the backing plate, put the mixed powder in the form of biscuits into the mold, and heat mold at hundreds of degrees Celsius to form the pad. In the next curing process, the brake pads are baked at 200 ° C. or higher for a long time, and the performance and mechanical strength of the brake pads are ensured.

  Needless to say brake pads, high temperature and stress are repeated due to sudden frictional heat when the brakes are applied. Therefore, high temperature adhesion, stress resistance and quality stability between the backing plate and the brake pads (heat resistant friction material) are required. Has been. Since the backing plate and the pad parts are one of the control parts that slow down or stop the automobile, it is absolutely not allowed for the brake pads to be peeled off during use.

  The conventional problem is that an adhesive is applied on the backing plate (back metal) and adhered by its adhesive force. When the vehicle is substantially decelerated or repeatedly stopped by braking with the pad, the adhesive layer is braked. When the adhesive layer with heat resistance rises suddenly by 800 ° C or more due to heating of the brake or is cooled down to room temperature, the adhesive Adhesive strength gradually deteriorated due to sudden changes in high temperature and cooling temperature, and the brake pads could peel from the backing plate when subjected to repeated large mechanical loads during braking.

JIS Handbook issued by the Japanese Standards Association: 2002 JIS D 0107 Automotive brake terms (parts) P149 JP 62-137183 A

  The problem to be solved by the present invention is that when a heat-resistant adhesive is repeatedly exposed to an environment of high temperature heating due to braking heat at the time of braking and rapid temperature change of rapid room temperature cooling, the disk is deteriorated as the adhesive deteriorates An object of the present invention is to solve the problem that the brake pads adhered due to vibration and impact generated by braking friction of the brake plate are peeled off.

Accordingly, in order to achieve the above object, the invention of claim 1 is a disc in which a brake pad made of a friction material is pressed against the surface of an automobile disc, and a friction braking force is generated by relative motion between the rotating disc surface and the friction material. Regarding brakes,
Expanded metal formed by meshing elongated steel materials meshed on a backing plate supported by an operating mechanism for operating in the direction in which the brake pad is brought into contact with the disc surface, and formed by overlapping the stacked metal. A welding step of sandwiching the protruding contact portion between a pair of electrodes, applying a welding pressure necessary for welding between the electrodes, and flowing a welding current to project and integrate the protruding contact portion;
When manufacturing a disc brake pad from a series of pad curing processes for forming and fixing the brake pad to the expanded metal integrated through the welding process,
In the welding process, the mesh height dimension after welding of the expanded metal is set within a predetermined reference range, which is a mesh height dimension at which the mechanical strength of a welded portion obtained in advance by experiment is obtained. The entire surface of the protrusion contact portion is projected and welded by supplying a large current for a short time from a capacitor power source based on the welding conditions corresponding to the above, whereby the mesh height dimension of the expanded metal integrated with the backing plate can be reduced. to provide a mounting method of the pad for a disc brake, characterized in that it is maintained within the predetermined criterion.

Next, according to the present invention, the expanded metal has substantially the same shape as the shape of the backing plate in a plan view, and is divided in the vertical direction to be integrated with each other so that adjacent expanded metals are separated from each other. A longitudinal groove corresponding to a plurality of friction limit warning grooves is formed .

Furthermore, the present invention is characterized in that in the welding step, the expanded metal is integrated by repeating projection welding several times by wrapping at least the first row of projection welds after welding.

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According to the first aspect of the present invention, a standard product expanded metal is used to be integrated with the backing plate by capacitor projection welding, and then an adhesive is applied to the integrated expanded metal, and then the biscuit-like mixing is performed on the mold. By inserting the powder, heat forming at several hundred degrees or more, and incorporating it into the shape of the pad, the pad material is brought into the expanded metal fine mesh over the entire range, so that the expanded metal is embedded inside the pad material and the brake pad It is firmly fixed to the backing plate as a fixing material and reinforcing bars. This impact force or finely dispersing the vibration force along the meshes of the mesh material is forced into the brake pads, would be absorbed, frictional heat further generated in the brake pad finely conducted along the mesh of the mesh material It will be dispersed and the durability will be dramatically improved. Therefore, it can cope with high temperature and cooling temperature change environment due to friction braking heating of the brake, and it can take several safety measures such as high temperature adhesion and stress resistance of the adhesive.

Further, according to the present invention, the expanded metal divided in the vertical direction of the brake pad and the disc brake is divided and welded on the backing plate by capacitor-type resistance welding, so that both friction surfaces are caused by the braking friction between the brake pad and the disc brake. A vertical groove can be formed during this welding process to sink wear metal particles or fine metal pieces generated from the friction limit warning groove and eliminate these foreign substances from the brake sliding surface. It is possible to simplify the work of machining the friction limit warning groove.

Further, according to the present invention, at least the first row of mesh welds after welding of the divided expanded metal is wrapped, that is, the first row of welds are sandwiched again between the electrodes and re-pressurized and energized in order. Projection welding.
As a result, when the power source capacity is small or the electrode pressing surface is narrow, the single plate can be integrated by repeating the welding several times. In this case, the contact point of the expanded metal is not completely flattened, and the mesh material can be firmly and uniformly melt bonded.

  According to the present invention, an optimum welding current can be made to flow evenly over the entire surface of the expanded metal projection contact that is always welded by a capacitor welding apparatus that can flow a large current in a short time. Due to heat generation, there is little warping of the backing plate due to thermal effects, distortion, and deformation and collapse of the expanded metal material.

  INDUSTRIAL APPLICABILITY The present invention is useful for a construction method for mounting a brake pad of an automotive disc brake. An expanded metal is overlapped on a backing plate, and a protruding contact portion formed by the overlap is a resistance welding method. This is a construction method that uses a capacitor-type projection welding method, which does not crush the expanded metal base material completely flatly, and reduces the crushing of the protruding contact portion and makes it melt and weld firmly.

FIG. 1 is a plan view showing a mesh shape defined in JIS G 3351 (expanded metal). Symbols S and L are the lengths in the vertical and horizontal directions of the product. FIG. 2 is an enlarged partial view of the same. Symbol T: plate thickness, W: step width, SW: mesh width direction distance, LW: mesh length direction distance. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2 and shows a protruding contact portion that overlaps the backing plate. Symbol h in the figure shows the height of the expanded metal.
Based on the mounting method of the present invention, a sample was prepared to confirm the actual performance.
Experimental values are shown below.

-Workpiece and material Backing plate: Material SAPH440, plate thickness 8mm, plate width 86mm
Length 106mm
Expanded metal: Material SPHC Wire diameter 0.8mm, width 80mm,
Length 100mm Height 2mm
・ Welding condition table Applied pressure kN: 20 to 25, Capacity kW: 15 to 20, Welding current kA: 160 to 180,
Energizing time ms: 10-20

  As a result of welding the backing plate and the expanded metal within the above experimental values, according to the projection welding method, which is one of the resistance welding methods, the entire surface of the expanded metal material is less likely to be crushed uniformly and melted and welded firmly. They could be integrated (see FIG. 5). In this welding experiment, an electrode having a flat pressure surface having a width of 25 mm and a length of 80 mm was used. The expanded metal was superimposed on the backing plate and sandwiched between the upper and lower electrodes, and was welded by a capacitor power supply in several times under welding conditions of a pressure of 20 kN, a welding current of 164 kA, and an energization time of about 10 ms. In this experiment, after one expanded metal was welded once, split welding was performed by lapping the mesh of the first row previously welded in the next welding. According to this welding result, the mesh height h dimension after welding of the expanded metal was ensured within the range of 1.4 mm to 1.6 mm with respect to the mesh height h dimension before welding of 2 mm. As a result of the pliers peeling test after welding, sufficient mechanical strength was obtained at each protrusion weld if the mesh height h dimension standard after welding was within the range of 1.4 mm to 1.6 mm (Fig. 6). In this experiment, even when the capacity of the power source was small, the results of a pliers peel test on the welded part by split welding in the same way confirmed that strong peel strength was obtained in terms of weld quality.

In the actual experiment shown in FIG. 4, the friction limit warning groove can be machined by this welding process if projection welding is performed by overlapping the backing metal obtained by dividing the expanded metal in advance in the vertical direction at equal intervals. In this process, the mesh material is divided into three parts and welded in advance, so that a large current can flow in a short time for each sheet. This expanded metal welding method allows the optimum welding current to flow evenly over the entire surface of the expanded metal that is always welded in capacitor welding, and because of the short-time heat generation, warping / distortion of the backing plate due to thermal effects, the material of the expanded metal material It was confirmed that there was little loss of mechanical properties of the base metal because there was little alteration or crushing.
In this welding experiment, the expanded metal divided into three parts was tested by split welding. However, in the case of overlapping welding, the same invention effect can be obtained by welding by wrapping the first row or by wrapping multiple rows. Needless to say, the entire expanded metal joint can also be welded simultaneously.

  With other resistance welding power sources, for example, with a single-phase AC power source, a large current cannot be flowed in a short time. In addition, the inverter power supply cannot flow a large current in as short a time as a single-phase AC power supply, so the warping and distortion of the backing plate is large, and the expanded metal material is greatly deformed and crushed, resulting in mechanical strength. There wasn't. For example, there is a method described in Japanese Patent Application Laid-Open No. 62-137183, which is a conventionally known method of spot welding steel expanded metal to a metal plate.

  In this conventional method, the spot where the expanded metal is spot welded is pressed prior to welding to make it completely flat, and then is subjected to normal spot welding in the state of surface contact with the mating plate. Characteristics cannot be obtained. On the other hand, the present invention makes use of the mechanical properties of expanded metal to contact the mating flat plate by a protruding contact point, and does not completely crush the base metal original shape (flat), By reducing crushing, mechanical strength as a mesh material can be secured.

  According to the brake pad mounting method of the present invention, since a large current can be passed in a short time, the expanded metal base material is less crushed and can be melted and welded firmly. In addition, in this experiment, the strength test of a sample made by capacitor projection welding of backing metal and expanded metal was verified by a pliers peel test. As a result, a strong peel strength was obtained and an improvement in welding quality was confirmed.

The expanded metal integrated by the welding process described above is applied to the pad in the next pad forming process, a biscuit-like mixed powder is put into the mold, and heat-molded at several hundred degrees to be incorporated into the pad shape. In this case, the pad base material penetrates to the entire area of the expanded metal mesh, so that a metal reinforcing material, that is, a steel expanded metal is embedded in the pad material. The brake pad is tempered and fixed to the backing plate through a series of processing steps such as a pad molding / curing step. Thus vibration force and impact force to be forced into the brake pad is would be finely dispersed and absorbed along the meshes of the mesh material and the frictional heat generated in the brake pads finely reticulated by expanded metal inner pad Conducted and dispersed, the durability of adhesive strength can be greatly extended.

  Although the present invention refers to a method for mounting a brake pad of an automotive disc brake, the standard steel expanded metal and backing plate can be firmly fixed without losing mechanical properties by capacitor-type resistance welding. In addition to drum brakes, it can also be used in other fields that require brake pads such as aircraft and trains.

It is a top view which shows the mesh shape prescribed | regulated to JISG3351 (expanded metal). It is an enlarged partial view of expanded metal. It is a figure which shows the protrusion contact state of the overlap part formed by overlapping the expanded metal on the backing plate in this invention. It is a top view which integrated the expanded metal divided into three into the backing plate in this invention. It is a photograph which shows the welding part external appearance detail which integrated one sheet of expanded metal with the backing plate in this invention. It is a photograph which shows the welding fracture part which carried out the peeling test of the welding part integrated in this invention.

Claims (1)

A disc brake that presses a brake pad made of a friction material against the surface of an automobile disc and generates a friction braking force by the relative movement of the rotating disc surface and the friction material.
Expanded metal formed by meshing elongated steel materials meshed on a backing plate supported by an operating mechanism for operating in the direction in which the brake pad is brought into contact with the disc surface, and formed by overlapping the stacked metal. A welding process in which a protruding contact portion is sandwiched between a pair of electrodes, a welding pressure is applied between the electrodes, a welding current is passed, and the protruding contact portion is integrated by projection welding.
When manufacturing a disc brake pad from a series of pad curing processes for forming and fixing the brake pad to the expanded metal integrated through the welding process,
In the welding process, the mesh height dimension after welding of the expanded metal is set within a predetermined reference range within a mesh height dimension that provides a mechanical strength of a welded portion obtained in advance by experiments. The entire surface of the protrusion contact portion is projection welded by supplying a large current for a short time from a capacitor power source based on the welding conditions corresponding to the above, whereby the mesh height dimension of the expanded metal integrated with the backing plate can be reduced. mounting method pad for a disc brake, characterized in that it is maintained within the predetermined criterion.

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