Inclined hole of air inlet

Abstract

A brake disc pad comprising a backing plate (1) having an inner surface (13) and a lining (2) secured to the inner surface (13), where the lining (2) comprises a collecting groove (3) open to a friction surface (26) of the lining (2), the backing plate comprising an air extraction hole (17) in fluid communication with the groove (3) and connected to a vacuum source, where the collecting groove (3) extends at one end thereof in a channel (90), where the air extraction hole (17) is in fluid communication with the collecting groove (3) and the air extraction hole (17) is in fluid communication with the collecting groove (3). The outer end (91) of the channel (90) is open outside the friction surface (26), and the channel (90) and the groove (3) form a cross-section fracture. The inclination angle (delta) between the axis of the channel (90) and the longitudinal axis (X) of the groove is non-zero and is arranged such that the airflow near the friction surface (26) of the lining (2) is not perpendicular to said friction surface.

Description

[0001] The present invention relates to a pollution-free braking system, which aims to be used in machinery including a rotating element, the rotation of which needs to be slowed down, such as road vehicles (cars, buses, trucks) or railway vehicles, as well as wind turbines. In such a braking system, due to the wear of the friction braking between the brake lining and the rotating element, particles and dust are emitted. Such a rotating element is, for example, a vehicle wheel or a disk driven by a vehicle wheel. As is well known, these particles dispersed in the environment are harmful to human health. In addition, the development of automotive electrification has increased the demand for dealing with the particles and dust generated by the wear of the friction braking system.

[0002] Therefore, it is necessary to capture these particles and dust before they are released into the surrounding environment. For this purpose, one way is to provide grooves connected to a vacuum source on the lining of a disk-brake or a brake-shoe, so as to discharge and suck the particles in the grooves.

[0003] Thus, a brake lining 10 for a disk brake is known, wherein the lining includes a backing plate 1 having an outer surface 14, an inner surface 13 and side edges 11, and a friction material lining 2 fixed to the inner surface 13, and the lining 2 is defined by a friction surface 26, an additional surface 20 and side edges formed by an inner edge 23, an outer edge 24, a rear edge 21 and a front edge 22. The lining 2 is provided with a collecting groove 3 opening on the friction surface 26 and near the rear edge 21, wherein the backing plate 1 includes an air extraction hole 17 in fluid communication with the collecting groove 3. The air extraction hole 17 is connected to a vacuum source through a fluid communication device.

[0004] However, during operation, as the lining wears, the suction performance will decline. In fact, the wear will cause an increase in the loss of linear load, and the load loss forces the flow rate of the vacuum source (such as a turbine) to decrease. In this case, the performance of the collecting groove in capturing particles and dust will be reduced.

[0005] In order to keep the capture performance constant even when the lining 2 wears, a brake lining is known, as described in document FR 3,087,238, wherein the collecting groove 3 extends at one end with a straight channel 90, the outer end 91 of which opens outside the friction surface 26 through an air inlet 911, and the inner end 92 of which opens into the collecting groove 3 through an air outlet 922 and forms a section break with the groove 3.

[0006] Such a lining is as Figures 13 to 16 shown. The function of the channel 90 is to create a negative pressure on either side between the air inlet 911 of the channel and the collecting groove 3 during operation.

[0007] In an alternative embodiment, the passage 90 extends parallel to the friction surface 26 and the inner surface 13 and opens at a side edge, such as side edge 23, as Figures 13 to 15 shown. Figure 13 is a top view of the pad. Figure 14 is a perspective view of the pad. Figure 15 is a sectional view along Figure 14 the slot 3 in

[0008] In another alternative embodiment, the passage 90 extends perpendicular to the friction surface 26 and the inner surface 13 and opens through the back plate at the outer surface 14, as Figure 16 shown. The advantage of this solution is that the passage 90 can be drilled during the manufacture of the back plate 1 and there is no need to form the passage 90 in the lining 2. Thus, the manufacture of the pad 10 is simplified and the cost is reduced.

[0009] Accordingly, a brake pad is known, wherein the pad comprises a back plate having an outer surface, an inner surface and a side edge, and a friction material lining fixed to the inner surface, the lining being defined by a friction surface, an additional surface and a side edge formed by an inner edge, an outer edge, a rear edge and a front edge, the lining being provided with at least one collecting groove opening at the friction surface and at least partially located near the rear edge, the back plate comprising at least one suction hole in fluid communication with at least one collecting groove, the at least one suction hole being connected to a vacuum source by a fluid communication means, the at least one collecting groove having a passage extending at least at one end thereof, the outer end of the passage opening outside the friction surface through an air inlet, the inner end of the passage opening into at least one collecting groove through an air outlet and forming a sectional break with at least one slot, such that during operation, a negative pressure is formed between the air inlet of the passage and at least one collecting groove through the passage.

[0010] As described above, the suction and capture of brake particles in the above brake system is accomplished by generating an air flow into the collecting groove. Tests conducted by the inventors have shown that the greater the air velocity near the surface of the disc (or wheel), the better the particle capture effect. This means that the faster the air flow along the friction surface of the lining, and thus the higher the air flow rate, the better the particle suction effect.

[0011] However, in order to limit the load loss and thus the power of the suction source, the air flow rate into the slot must be reduced. Thus, there are two competing requirements. SUMMARY OF THE INVENTION

[0012] The present invention aims to provide a brake pad for increasing the air flow velocity along the friction surface of the lining without increasing the flow rate through the collecting groove.

[0013] This object is achieved by the fact that the inclination angle between the channel axis and the longitudinal axis of the groove is non-zero and is arranged obliquely such that the air flow near the friction surface of the lining is not perpendicular to the friction surface.

[0014] Due to these arrangements, the velocity distribution of the air flow through the groove reaches a maximum along the friction surface of the lining in the height direction of the groove. Thereby, the particle suction in the groove is optimized.

[0015] For example, the inclination angle is decomposed into a main angle in a plane perpendicular to the plane of the friction surface and a secondary angle in the plane of the friction surface, where the main angle is measured as positive in the direction from the plane of the friction surface towards the back plate around the outlet of the groove outside the groove, and the main angle is in the range ]0°, 135°].

[0016] For example, the secondary angle is zero.

[0017] For example, the outer end opens from the side of one of the edges.

[0018] For example, the channel passes through the back plate, where the outer end opens to the outer surface or the side edge of the back plate.

[0019] For example, at least one collecting groove is formed by a single groove extending along the rear edge.

[0020] For example, the collecting groove also extends along the front edge.

[0021] For example, the collecting groove is in a C shape or an E shape or an annular shape and extends along the outer edge and / or the inner edge.

[0022] For example, the inclination angle is decomposed into a main angle in a plane perpendicular to the plane of the friction surface and a secondary angle in the plane of the friction surface, where the secondary angle is measured as positive in the trigonometric direction around the axis in the direction from the bottom to the top of the groove from the plane towards the outside of the groove, and the secondary angle is non-zero and between -90° and 90°.

[0023] For example, the secondary angle is negative.

[0024] By reading the following detailed description of the embodiments shown as non-limiting examples, the present invention can be better understood, and its advantages will become more clearly visible. The description of the present invention relates to the accompanying drawings, which include:

[0025] Figure 1 is a perspective view of a brake lining according to the present invention;

[0026] Figure 2 is a sectional view of the collecting groove of the brake lining according to the present invention along the line II-II in Figure 1 ;

[0027] Figure 3is a cross-sectional view of the flow collector groove of a brake pad according to another embodiment of the present invention, which has a channel opening at the side edge of the back plate;

[0028] Figure 4 is a cross-sectional view of the flow collector groove of a brake pad according to yet another embodiment of the present invention, which has a channel opening at the outer surface of the back plate at a main angle strictly less than 90°;

[0029] Figure 5 is a cross-sectional view of the flow collector groove of a brake pad according to yet another embodiment of the present invention, which has a channel opening at the outer surface of the back plate at a main angle strictly greater than 90°;

[0030] Figure 6 is a perspective view of a braking system including a brake pad according to the present invention;

[0031] Figure 7 shows various values of the main angle of the channel of the brake pad according to the present invention and the flow of the air current in the groove;

[0032] Figure 8 shows the brake pad according to the present invention in the case where the main angle of the channel is equal to 45°, and its secondary angles θ are respectively equal to 0°, 45° or 90°;

[0033] Figure 9 shows the flow of the air current in the groove in the case where the main angle is equal to 45° and the secondary angle is equal to -50°;

[0034] Figure 10 shows the flow of the air current in the groove in the case where the main angle is equal to 45° and the secondary angle is equal to 45°;

[0035] Figure 11 is a perspective view of a brake pad according to another embodiment of the present invention, which has a C-shaped groove and channels at each end of the groove;

[0036] Figure 12 is a top view of a brake pad according to yet another embodiment of the present invention;

[0037] Figure 13 As described above, shows a top view of a pad in the prior art;

[0038] Figure 14 As described above, shows a perspective view of a pad in the prior art;

[0039] Figure 15 As described above, is along Figure 14 in the direction of line XV-XV in Figure 14 a cross-sectional view of the flow collector groove of the brake pad in

[0040] Figure 16 As described above, it is a sectional view of the collecting groove of the brake pad variant in Figure 14 . DETAILED DESCRIPTION

[0041] The present invention relates to a brake pad 10 in a braking device for a rotating element 9 of a machine. The application of the present invention in the case where the machine is a road vehicle and the braking device is a disc brake is described below. However, the present invention is equally applicable to the case of a brake pad in a brake shoe for a friction wheel, which can be used for a railway track (railway), or to a brake pad in any other industrial machine (such as a windmill). In all cases, braking of the rotating element of the machine is achieved by friction of the brake pad on the rotating element during its own rotation.

[0042] In a disc brake, braking is achieved by friction between a disc (i.e., the rotating element 9) fixed to a vehicle wheel and two brake pads 10, which are pressed against both sides of the disc 9 to clamp the disc. The disc 9 extends in a main plane and has a rotation axis, i.e., axis A, which is perpendicular to the main plane. Each pad 10 extends in the main plane such that the thickness of the pad 10 extends along the rotation axis A.

[0043] The disc 9 rotates about the rotation axis A in a rotation direction FW, which defines a tangential direction T that is tangent to the circumference of the disc 9 and oriented towards the rotation direction FW, and a radial direction R that is orthogonal to the rotation axis A in the main plane of the disc 9. These elements are shown in Figure 6 and Figure 6 shows a braking device mounted on the disc 9.

[0044] In the following description, "inner" and "outer" refer respectively to the edges or regions of the brake pad 10 (or its components) that are closest to and farthest from the rotation axis A, and the terms "front" and "back" refer respectively to the edges or regions of the brake pad 10 (or its components) that are located upstream and downstream of the direction of movement of the particles 28 released relative to the lining 2 (described below), which direction is also the rotation direction FW.

[0045] As Figure 1 and 2 shown, the brake pad 10 includes a backplate 1, also referred to as a base. The backplate 1 is made of metal, for example. The backplate 1 is a flat plate with a substantially constant thickness (e.g., between 3 and 5 mm), and its overall shape in the main plane is trapezoidal, having straight or curved edges. The backplate 1 includes an inner surface 13 to which the lining 2 is attached, and an outer surface 14 that is opposite and parallel to the inner surface 13. These two surfaces are connected by side edges 11.

[0046] The brake lining 10 further includes a lining 2 made of a friction material. For example, the material is a material called "ferodo". The lining 2 is defined by a friction surface 26 (the "frictional" surface), an additional surface 20 opposite to the friction surface 26 (the two surfaces are parallel to each other) and fixed to the back plate 1, an inner edge 23, an outer edge 24, a rear edge 21 and a front edge 22. The outer edge 24, the rear edge 21 and the front edge 22 are convex or straight, while the inner edge 23 is concave or straight.

[0047] As the lining 2 wears, the friction surface 26 gradually approaches the back plate 1. Therefore, the thickness of the lining 2 (measured along the rotation axis A) becomes thinner as it wears. During operation, due to the friction between the lining 2 and the disc 9, the lining 2 (and the rotating element 9) releases particles 28. The particles 28 are shown in dashed lines along the trajectory of the friction surface 26 in Figure 1 and Figure 13 and 14 in.

[0048] The lining 2 is provided with at least one collecting groove 3 opening to the friction surface 26, and the collecting groove 3 is located near the rear edge 21.

[0049] For example, the surface area of the part of the friction surface 26 located between the rear edge 21 and the groove 3 is less than 10% of the entire surface area of the friction surface 26.

[0050] The depth of one or more grooves 3 is less than the height of the lining 2 (measured in a plane perpendicular to the friction surface 26), which means that there is still some lining 2 between the bottom of each groove 3 and the inner surface 13 of the back plate 1. The distance between the bottom of each groove 3 and the inner surface 13 (measured perpendicular to this inner surface 13) is called the "remaining height", for example equal to 20% of the initial height of the lining 2 (before wear). This remaining height is, for example, equal to 10% of the initial height. This remaining height is, for example, equal to 5% of the initial height. This remaining height is, for example, equal to 1% of the initial height.

[0051] Alternatively, the depth of one or more grooves 3 is equal to the height of the lining 2, which means that the bottom of one or more grooves 3 coincides with the inner surface 13 of the back plate 1.

[0052] Alternatively, the depth of one or more grooves 3 is greater than the height of the lining 2, which means that the bottom of the one or more grooves 3 is located within the thickness of the back plate 1 (in other words, the bottom of the one or more grooves 3 is a recess in the back plate 1 and does not open to the outer surface 14 except for a dot-like opening (see below)).

[0053] The current collector channel 3 or at least one current collector channel 3 extends at least partially along the rear edge 21 and extends in a straight line or in a curve along the rear edge 21. The minimum dimension of the channel 3 is its thickness, measured substantially in the tangential direction T within the main plane of the pad 10.

[0054] For example, the one or more current collector channels 3 have a constant rectangular cross-section from their upstream end to their downstream end and thus have a constant thickness.

[0055] The liner 2 is provided, for example, with a single continuous channel, which is substantially straight or has one or more bends between two or more substantially straight portions.

[0056] Alternatively, the liner 2 is provided with a plurality of non-intersecting current collector channels 3. Non-intersecting channels means that these channels are not connected to each other except possibly through a passage 90 as described below.

[0057] Thus, in the present invention, the liner 2 either has a single current collector channel 3 (the only channel) or has a plurality of non-intersecting current collector channels 3. For example, in addition to the current collector channel 3 near the rear edge 21, the liner 2 further includes a second current collector channel 3 (opening to the friction surface 26). For example, this second channel 3 is located at an intermediate position between the rear edge 21 and the front edge 22 and extends from near the inner edge 23 to near the outer edge 24, while optionally opening to the inner edge 23 or the outer edge 24.

[0058] In summary, according to the present invention, the liner 2 is provided with (has) at least one current collector channel 3, which at least one current collector channel 3 either consists of a single current collector channel, at least part of which extends along the rear edge 21, or consists of a plurality of non-intersecting channels and includes a first channel 3a extending along the rear edge 21.

[0059] In the case of a single current collector channel 3, the channel includes a single straight or curved portion, or consists of a plurality of straight or curved portions connected by a network of bends to form a combined channel portion. At this time, the current collector channel 3 is convex.

[0060] An air flow is generated in the current collector channel 3, as described below, and this air flow 10 is generated by a vacuum source (suction system).

[0061] In the following part of this specification, reference is made to Figures 1 to 5 , and the case where a single current collector channel 3 extends at one end with a passage 90 opening from the side of the lower edge 23 is described (see below). The present invention is equally applicable to the case where the current collector channel 3 opens from the side of the outer edge 24. Figure 8 and Figure 9 The case where the current collector channel 3 extends at one end with a passage 90 opening from the side of the inner edge 23 is also shown. The channel 3 is not necessarily the only one; there may be at least another channel 3 in the liner 2 (not shown in these figures).

[0062] "The channel 90 opens from one edge side" means that one end of the channel 90 opens near the edge, that is, either through the back plate 1 or directly opens at the edge.

[0063] In each case, the channel 90 opens from one of its ends outside the friction surface 26. Therefore, the channel 90 either opens at the edge (21, 22, 23, 24), or passes through the back plate 1, or opens into another groove.

[0064] As Figure 1 and 2 as well as Figures 3 to 5 shown, the collecting groove 3 is, for example, a groove extending along the rear edge 21, having a first end and a second end. The longitudinal axis X of the groove 3 is defined as parallel to the plane H of the friction surface 26 and along this axis the groove 3 extends from its first end. If the groove 3 is straight, then the longitudinal axis X extends from the first end to the second end of the groove 3, and the plane V of the groove 3 is a plane perpendicular to the friction surface 26 in which the groove 3 extends. If the groove 3 is curved, the plane V is defined as the plane in which the groove 3 starts to extend at its first end. Therefore, in each case, the plane V of the groove 3 contains the longitudinal axis X.

[0065] Near the outer edge 24, the groove 3 ends at its second end with a blind end 31 that does not open at the outer edge 24.

[0066] Near this blind end 31, the back plate 1 includes a through suction hole 17 that opens into the groove 3. The suction hole 17 is visible in Figure 2 . Therefore, the particles 28 sucked into the groove 3 enter the suction hole 17 and then into the hose 40 that is part of the suction system. The air carrying these particles 28 is transferred from the groove 3 through the suction hole 17 (in fluid communication). One end of the hose 40 is connected to the suction hole 17. These components can be seen in Figure 2 .

[0067] The hose 40 is connected to a suction mechanism (not shown) that is part of the suction system, and this suction mechanism is capable of sucking the particles 28 from the groove 3 through the hose 40.

[0068] The collecting groove 3 extends near its first end with a channel 90. The channel 90 consists of continuous side walls connecting two ends and only opens at these two ends. Therefore, the channel 90 forms a tunnel. The tunnel is straight, and the axis of the channel 90 is thus straight, which allows it to be drilled. Alternatively, the tunnel is curved. In this case, the axis of the channel 90 is defined as the axis from which the channel 90 starts to extend from the collecting groove 3 (that is, starting from the inner end 92 of the channel 90, as defined below).

[0069] Advantageously, when the channels 90 are drilled, the cross-section of the channels 90 remains constant throughout the useful life of the liner 10 , thereby maintaining the suction performance of the manifold for the particles 28 .

[0070] The channel 90 opens at its outer end 91 from the inner edge 23 side through the air inlet 911. The channel 90 opens at its inner end 92 in the manifold 3 through the air outlet 922. The air outlet 922 forms a cross-sectional break with the groove 3, i.e., the cross section from the channel 90 to the groove 3 increases suddenly (step-shaped).

[0071] This increase in cross section Figure 2 As can be seen, Figure 2 is along Figure 1 The cross section of line III I I in FIG. 1 , i.e., the entire length of the collecting groove 3 and the channel 90 from the inner edge 23 to the outer edge 24.

[0072] Due to this sudden increase in the cross section (in the normal direction of the air flow), during operation, a negative pressure exists on both sides between the air inlet 911 of the channel 90 and the collecting groove 3, that is, along the channel 90.

[0073] Furthermore, according to the invention, the axis of the channel 90 forms a non-zero angle δ with the longitudinal axis X of the groove 3. The angle δ is called the inclination angle and is Figure 8 Therefore, in general, the inclination angle δ is decomposed into a primary angle β in a plane (eg, plane V) perpendicular to the plane of the friction surface 26 (plane H), and a secondary angle θ in plane H of the friction surface 26 .

[0074] In the particular case, the secondary angle θ is zero, the channel 90 being inclined only along the main angle β in the plane V of the groove 3 .

[0075] In another particular case, the primary angle β is zero and the channel 90 is inclined only along a secondary angle θ in a plane parallel to the plane H of the friction surface 26 .

[0076] The main angle β is measured as positive around the air outlet 922 outside the groove 3 from the plane H of the friction surface 26 in the direction of the back plate 1. The main angle β is always positive. Therefore, except for the other special case described above, the air flowing from the air inlet 911 to the air outlet 922 through the channel 90 is always directed toward the friction surface 26. In fact, in this other special case, the main angle β is zero and the secondary angle θ is non-zero, so the air leaves the channel 90 in a plane parallel to the plane H of the friction surface 26.

[0077] The secondary angle θ is positive when measured trigonometrically from plane V (in plane H) outward from the slot 3 and around the axis from the bottom to the top of the slot 3.

[0078] When the channel 90 is straight, the axis of the channel 90 is a straight line connecting the center of the air inlet 911 and the center of the air outlet 922. When the channel 90 is curved, the axis of the channel 90 is taken as the tangent to the curve connecting the center of the cross-section of the channel 90 at the center of the air outlet 922.

[0079] In a specific case where the secondary angle θ is zero, that is, the channel 90 is inclined only along the main angle β in the plane V of the groove 3, there is a strictly positive value (therefore non-zero) of the main angle β, which means that the velocity distribution of the air flow leaving the channel 90 and entering the groove 3 in the height direction of the groove 3 reaches a maximum along the friction surface 26 of the lining. The inventor observed this distribution through experiments. Figure 7 The resulting velocity distributions are shown, that is, when the tilt angle δ is zero ( Figure 7 (a)), the tilt angle δ when the main angle β is 45° and the secondary angle θ is zero ( Figure 7 (b)), the tilt angle δ when the main angle β is 75° and the secondary angle θ is zero ( Figure 7 (c)), and the tilt angle δ when the main angle β is 135° and the secondary angle θ is zero ( Figure 7 (d)). The region M with the maximum velocity in the groove 3 is surrounded by a dashed line. Note that in case (a) (where the channel 90 has no tilt), the region M is located at the bottom of the groove 3, that is, near the inner surface 13. In contrast, in cases (b), (c), and (d), the channel 90 is tilted in the plane V of the groove 3, and the region M is located along the friction surface 26.

[0080] Tests conducted by the inventor show that Figure 7 the results shown regarding the longitudinal velocity (along the longitudinal axis X) near the friction surface 26 in the case where the secondary angle θ is zero qualitatively remain the same for all values of the secondary angle θ (i.e., between -90° and 90°). Therefore, this longitudinal velocity varies between two values of the secondary angle θ (in absolute value), but for two secondary angles θ with the same absolute value and opposite signs, this longitudinal velocity is the same.

[0081] According to the present invention, the tilt angle δ between the axis of the channel 90 and the longitudinal axis X of the groove 3 is non-zero, and the tilt is set such that the air flow is not perpendicular to the friction surface near the friction surface 26 of the lining 2. In particular, the tilt angle δ is not perpendicular to the plane H of the friction surface 26. In fact, in this case (main angle β = 90° and secondary angle θ = 0), the longitudinal velocity of the air flow generated in the groove 3 near the friction surface 26 is not the maximum, and the transverse velocity of this air flow (the velocity perpendicular to the longitudinal axis X near the friction surface 26) is zero. Therefore, this is a situation where the air flow is not optimal near the friction surface 26.

[0082] In addition, tests carried out by the inventors have shown that when the secondary angle θ is within the interval [–15°, 15°] and the primary angle β is within the angle [60°, 85°], the total velocity distribution (the total velocity being the vector sum of the longitudinal velocity and the transverse velocity) is maximum and is substantially in the direction of the friction surface (26).

[0083] These tests have also shown that the transverse velocity of the air flow is not negligible (i.e., non-zero and of the same order of magnitude as the longitudinal velocity of the air flow) in two cases:

[0084] - The first configuration, where the primary angle β is less than 40° and the secondary angle θ is outside the interval [–10°, 10°]

[0085] outside.

[0086] - The second configuration, where the primary angle β is greater than 40° and the secondary angle θ is outside the interval [–20°, 20°]

[0087] outside.

[0088] In the first embodiment, as Figure 1 and Figure 2 shown, the channel 90 opens near its air inlet 911 at the lower edge 23.

[0089] Thus, during operation, air flows from the air inlet 911 through the channel 90 to the air outlet 922, then enters the groove 3 and flows towards the suction hole 17, and finally enters the hose 40, thereby discharging the particles and dust 28 in the air. This air circulation is applicable to Figures 1 to 5 the situation shown.

[0090] The channel 90 has a constant circular cross-section. Alternatively, the channel 90 has a non-circular cross-section and / or a variable cross-section.

[0091] Advantageously, the air inlet 911 opens at the inner edge 23 of the gasket 2 (or generally at one of the edges (21, 22, 23, 24) of the gasket 2) closest to the back plate 1 and in an area that will not be consumed at the end of the normal service life of the gasket 10. Thus, the air inlet 911 opens at a position greater than the remaining height of the gasket 2 (see above) from the inner surface 13 of the back plate 1.

[0092] Thus, throughout the service life of the gasket 10, the cross-section of the channel 90 remains constant, and the suction performance of the collecting groove for the particles 28 is maintained.

[0093] When the channel 90 is at a height equal to this remaining height, the channel 90 acts as a visual wear indicator. In fact, the wear of the gasket 2 reaching the channel 90 indicates that the gasket 10 has reached the end of its service life.

[0094] In other embodiments, such as Figure 3 and Figure 5 shown, the channel 90 does not open at the lower edge 23 near its air inlet 911. Instead, the channel 90 passes through the back plate 1 from the manifold 3 to open at the back plate 1 near its air inlet 911. The advantage of this solution is that the channel 90 can be drilled during the manufacturing process of the back plate 1 without forming the channel 90 in the liner 2. Therefore, the manufacturing of the gasket 10 is simplified and the cost is reduced. The air outlet 922 is always located near the inner surface 13 of the back plate 1.

[0095] In one of these embodiments (the second case), such as Figure 3 shown, the air inlet 911 opens at the side edge 11 of the back plate 1. At this time, the main angle β must be strictly less than 90°.

[0096] In another of these embodiments (the third case), such as Figure 4 and Figure 5 shown, the air inlet 911 opens at the outer surface 14 of the back plate 1. At this time, the main angle β must be strictly less than 180°. Figure 4 Shows the case where the main angle β is in the interval ]0°, 90°[. Figure 5 Shows the case where the main angle β is in the interval ]90°, 180°[.

[0097] In the above embodiments and Figures 2 to 5 and Figure 7 shown cases, the axis of the channel 90 lies in the plane V of the groove 3. Therefore, the secondary angle θ is zero.

[0098] In another embodiment, a non-zero secondary angle θ between -90° and 90° is formed between the axis of the channel 90 and the longitudinal axis X of the groove 3.

[0099] This other embodiment is shown in Figure 8 in Figure 8 (b), where the secondary angle θ is equal to 45°, and in Figure 8 in Figure 8 (c), where the secondary angle θ is equal to 90°. For reference, Figure 8 in Figure 8 (a) shows the case where the secondary angle θ is equal to 0°. At this time, the tilt angle δ is equal to the main angle β. In Figure 8 , in the three cases (a), (b) and (c), the main angle β is, for example, equal to 45°.

[0100] Compared with the embodiment where the secondary angle θ is zero, this other embodiment has additional advantages. In fact, the particles generated by the friction between the liner and the disc (or wheel) of the vehicle are naturally carried laterally relative to the groove 3 along the friction surface 26 ( Figure 1the arrow 28) in it. These particles thus tend to cross over the groove 3 without entering it and escape into the atmosphere, which is a problem.

[0101] Surprisingly, tests conducted by the inventors have shown that when the data of the secondary angle is non-zero, a transverse air flow (in a direction perpendicular to the longitudinal axis X) may be generated near the friction surface 26 and vortices may be formed in the vicinity thereof, and this air flow is in a direction opposite to the flow direction of these particles (arrow 28). Such an air flow thus helps to prevent the particles from escaping from the groove 3.

[0102] When the secondary angle θ is negative, a transverse air flow that helps to prevent the particles from escaping from the groove 3 is more specifically generated. In particular, such an air flow is generated when the secondary angle θ is within the range [–80°, –10°]. Figure 9 The air flow in the case where the primary angle β is equal to 45° and the secondary angle θ is equal to –50° is shown. Arrow P1 shows the majority direction of the air flow, especially near the friction surface 26. It can be seen that this air flow flows in a direction opposite to the flow direction of the particles along the friction surface (arrow P1 is collinear with arrow 28 but in the opposite direction). Therefore, the air flow from the channel 90 helps to make the particles enter the groove 3. Tests conducted by the inventors have shown that for the case where the primary angle β is within the range [25°, 75°] and the secondary angle θ is within the range [–50°, –25°], the transverse velocity of this air flow reaches the maximum value.

[0103] For certain positive values of the secondary angle θ, experiments conducted by the inventors have shown that the transverse air flow generated by it near the friction surface 26 does not prevent the particles from escaping from the groove 3 and may even enhance such escape. Therefore, these values of the secondary angle θ correspond to adverse cases. Figure 10 The case where the primary angle β is equal to 45° and the secondary angle θ is equal to 45° is shown. Arrow P2 shows the majority direction of the air flow, especially near the friction surface 26. It can be seen that this air flow flows in the same direction as the flow direction of the particles along the friction surface (arrow P2 is collinear with arrow 28 and in the same direction). Therefore, the air flow from the channel 90 helps to take the particles out of the groove 3.

[0104] Now, referring to Figure 11 Another embodiment of the present invention will be described. Figure 11 A brake pad in the railway field is shown.

[0105] The flow collector groove 3 is a single C-shaped groove that extends along the rear edge 21 and the front edge 22. The middle part of the flow collector groove 3 extends along the outer edge 24 and connects the front and rear parts of the flow collector groove 3. The rear part of the flow collector groove 3 (extending along the rear edge 21) has a channel 90 extending near its first end, and this channel 90 opens from the side of the inner edge 23. The front part of the flow collector groove 3 (extending along the front edge 22) has another channel 90 extending near its second end, and this channel 90 opens from the side of the inner edge 23.

[0106] Each channel 90 is similar to one of the channels 90 referred to in the reference Figures 1 to 5 One of the described channels 90. Alternatively, each of the two channels 90 has a different geometry from the other channel 90, such as a different cross-section, to balance the flow rate.

[0107] The back plate 1 includes a through air extraction hole 17, and this air extraction hole 17 opens at the rear part of the groove 3, as Figure 11 shown. The groove 3 widens here (the groove 3 may not widen in this area either). Alternatively, the air extraction hole 17 opens at the front part or the middle part of the groove 3. In all cases, the air extraction hole 17 is located at a position away from the end of the flow collector groove 3.

[0108] In the above embodiment, the liner 2 is provided with a single groove 3.

[0109] In another embodiment of the present invention, the liner 2 is provided with a plurality of non-intersecting flow collector grooves 3. The possible configurations at this time are as follows:

[0110] In the first configuration, the inner end 92 of at least one channel 90 opens at one end of one of the grooves 3, and its outer end 91 opens from the side of one of the edges (21, 22, 23, 24) of the liner 2.

[0111] In the second configuration, the inner end 92 of at least one channel 90 opens at one end of one of the grooves 3, and its outer end 91 opens at one end of another groove 3.

[0112] In the third configuration, which is a combination of the first configuration and the second configuration, the inner end 92 of at least one channel 90 opens at one end of one of the grooves 3, and its outer end 91 opens from the side of one of the edges (21, 22, 23, 24) of the liner 2, and the inner end 92 of at least another channel 90 opens at one end of one of the grooves 3, and its outer end 91 opens at one end of another groove 3.

[0113] Figure 12 An example of the second configuration is shown, where the liner 2 is provided with only two non-intersecting flow collector grooves 3, namely the first groove 3a and the second groove 3b. The first groove 3a and the second groove 3b extend along each other and along the rear edge 21. A single channel 90 extends between the first end of the first groove 3a and the first end of the second groove 3b.

[0114] Therefore, the channel 90 opens into the second groove 3b through the air inlet 911 at its outer end 91. The channel 90 opens into the first groove 3a through the air outlet 922 at its inner end 92. The air outlet 922 is located at the first end of the first groove 3a.

[0115] The second end of the first groove 3a is a blind end 31 and does not open to the outer edge 24. Near the blind end 31, the back plate 1 includes a through suction hole 17 that opens into the groove 3.

[0116] The second end of the second groove 3b opens to the inner edge 23.

Claims

1. A brake lining (10), wherein the lining comprises a back plate (1) having an outer surface (14), an inner surface (13) and side edges (11), and a friction material lining (2) fixed to the inner surface (13), wherein, The lining is bounded by a friction surface (26), an additional surface (20), and side edges formed by an inner edge (23), an outer edge (24), a rear edge (21), and a front edge (22). The lining (2) is provided with at least one collecting groove (3) that opens onto the friction surface (26) and is at least partially close to the rear edge (21). The back plate includes at least one air extraction hole (17) that is in fluid communication with the at least one collecting groove (3). The at least one air extraction hole (17) is connected to a vacuum source through a fluid communication device. The at least one collecting groove (3) extends a channel (90) at at least one of its ends. The outer end (91) of the channel (90) opens outside the friction surface (26) through an air inlet (911), and its inner end (92) opens into the at least one collecting groove (3) through an air outlet (922) and forms a cross-section break with the at least one groove (3). So that during operation, a negative pressure is formed between the air inlet (911) of the channel (90) and the at least one collecting groove (3) through the channel (90). And the channel (90) is characterized in that the inclination angle (δ) between the axis of the channel (90) and the longitudinal axis (X) of the groove (3) is non-zero, and is inclined such that the air flow near the friction surface (26) of the lining (2) is not perpendicular to the friction surface (26).

2. The brake pad (10) according to claim 1, wherein the inclination angle (δ) is decomposed into a main angle (β) in a plane (V) perpendicular to the plane (H) of the friction surface (26) and a secondary angle (θ) in the plane (H) of the friction surface (26). The main angle (β) is measured as a positive value around the air outlet (922) outside the groove (3) in the direction from the plane (H) of the friction surface (26) towards the back plate (1), and the main angle (β) is in the interval ]0°, 135°].

3. The brake pad (10) according to claim 1 or 2, wherein the secondary angle (θ) is zero.

4. The brake pad (10) according to claim 3, wherein the outer end (91) opens from the side of one of the edges (21, 22, 23, 24).

5. The brake pad (10) according to claim 3, wherein the channel (90) passes through the back plate (1), and the outer end (91) opens onto the outer surface (14) or the side edge (11) of the back plate (1).

6. The brake pad (10) according to any one of claims 1 to 5, wherein the at least one collecting groove (3) is constituted by a single groove extending along the rear edge (21).

7. The brake pad (10) according to claim 6, wherein the collecting groove (3) also extends along the front edge (22).

8. The brake pad (10) according to claim 7, wherein the collecting groove (3) is in a C shape or an E shape or an annular shape and extends along the outer edge (24) and / or the inner edge (23).

9. The brake pad (10) according to claim 1 or 2, wherein the inclination angle (δ) is decomposed into a main angle (β) in a plane (V) perpendicular to the plane (H) of the friction surface (26) and a secondary angle (θ) in the plane (H) of the friction surface (26), the secondary angle (θ) being measured as positive in a trigonometric direction around an axis in the direction from the bottom to the top of the groove (3) towards the outside of the groove (3) from the plane (H), and the secondary angle (θ) being non-zero and between -90° and 90°.

10. The brake pad (10) according to claim 9, wherein the secondary angle (θ) is negative.

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