Disc brake for vehicles including elastic return means for the guide pin

Abstract

The disc brake (2) for a vehicle (1) comprises: - a fixed bracket, - a caliper (4) mounted to slide relative to the bracket between a rest position and a braking position, - at least two guide pins (7) integral with the caliper and designed to cooperate with a respective bore (8) formed in the bracket in order to guide the sliding of the caliper relative to the bracket. Each guide pin is movable in translation within its bore between a braking position and a rest position in which the guide pin is more retracted into the bore than in the braking position. The brake includes, within at least one of the bores, means for elastically returning the guide pin to the rest position. Figure for the abbreviation: Figure 4

Description

Title of the invention: Disc brake for vehicle comprising elastic return means for the guide column Technical field of the invention

[0001] The invention relates to a disc brake for a vehicle as well as to a vehicle comprising such a disc brake. Technical background

[0002] Floating caliper disc brakes conventionally comprise a yoke carried by the hub of the vehicle wheel and a caliper intended to slide relative to the yoke during braking, under the action of a clamping member such as a piston, in order to allow the brake pads to grip the disc to perform braking. The sliding is guided by guide columns secured to the caliper and intended to slide in corresponding bores provided in the yoke. In general, a disc brake, in particular a hydraulically actuated disc brake, does not comprise dedicated means intended to move the pads back after braking. The piston is moved back by means of the square joint and the disc web which pushes the brake pads back.The friction between the disc and the brake pads after braking creates a residual braking torque for a more or less long period of time which causes unwanted braking and premature wear of the brake pads. This residual braking torque, when it is not distributed evenly over all the wheels, also has an unwanted influence on the dynamic behavior of the vehicle.

[0003] To overcome these drawbacks, it is known to use springs placed directly on the one hand on an external surface of the yoke and on the other hand on an external surface of the body of the caliper so as to move the caliper away from the yoke after braking, thus making it possible to separate the brake pads from the disc and therefore to reduce the residual braking torque. However, the springs used have complex geometries and are difficult and expensive to implement. In addition, these springs are exposed to external mechanical and / or chemical attacks which reduce their service lives. For example, they are exposed to projections of gravel when the vehicle is traveling on a ground comprising it or to projections of water when the ground is wet. Summary of the invention

[0004] The invention aims in particular to reduce, or even prevent, the presence of residual braking at the end of braking in a simple, economical and sustainable manner.

[0005] To this end, the invention relates to a disc brake for a vehicle, comprising: - a fixed yoke, - a caliper mounted to slide relative to the yoke between a rest position and a braking position, - at least two guide columns secured to the caliper and each intended to cooperate with a respective bore provided in the yoke in order to guide a sliding of the caliper relative to the yoke, each guide column being movable in translation in its bore between a braking position and a rest position in which the guide column is further retracted into the bore than in the braking position, characterized in that the brake comprises, inside at least one of the bores, means for elastically returning the guide column to the rest position.

[0006] It is understood that the elastic return means, at the end of braking, make it possible to elastically return the guide column to the rest position so that the caliper, secured to the guide column, slides into the rest position. The passage of the caliper into the rest position makes it possible to move the brake pads away from the disc so that the residual braking is reduced, or even absent.

[0007] The fact that the elastic return means are arranged in the bore made in the yoke advantageously makes it possible to protect them from external attacks, for example from mechanical attacks, such as a projection of gravel, or from chemical attacks, such as a projection of water. The service life of the elastic return means is therefore increased.

[0008] The rest position of the caliper corresponds to the position of the caliper outside of a braking period, when the brake pads are not in contact with the disc. The braking position of the caliper corresponds to the position of the caliper during braking. This is typically the position of the caliper when the brake pads carried by it grip the disc to perform braking. Conventionally, when moving from the rest position to the braking position, the caliper moves away from the yoke once the inner brake pad has reached the disc. This moving away of the caliper allows the outer brake pad to be brought closer to the disc so that the inner and outer brake pads grip it. Conversely, when the caliper moves from the braking position to the rest position, the caliper moves closer to the yoke.The guide columns being integral with the caliper, they follow a similar trajectory and slide between their rest and braking positions. It is therefore understood that when moving from the rest position to the braking position, the guide columns slide in their respective bores so as to protrude further from the bores. Conversely, when moving from the braking position to the rest position, the guide columns slide inside their respective bores so as to be retracted further into the bore than in the braking position. The elastic return means according to the invention make it possible to . facilitate and accelerate the transition from the braking position to the rest position of the guide columns, and therefore also the transition of the caliper from the braking position to the rest position, thus reducing or even eliminating residual braking.

[0009] The invention may include one or more of the following optional features, taken alone or in combination.

[0010] Advantageously, the disc brake comprises, inside each bore, means for elastically returning the guide pin to the rest position. Thus, each pin is returned to the rest position at the end of braking, which facilitates the sliding of the caliper and reduces the risk of the latter blocking during sliding.

[0011] Preferably, the bores are blind. Thus, the elastic return means are better protected from possible external attacks such as mechanical or chemical attacks. Advantageously, provision is made for the opening of the bore to be closed in a liquid-tight and gas-permeable manner. For example, the bores are closed by a bellows made of liquid-tight and gas-permeable material, the bellows. Such a bellows is also called a column cap.

[0012] Advantageously, the elastic return means comprise a tension spring fixed by its ends on the one hand to one end of the bore and on the other hand to one end of the guide pin present in the bore. The use of a tension spring is a simple, effective and economical means of allowing an elastic return of the guide pins to the rest position. It is understood that during braking, the caliper moves away from the yoke so that the guide pins slide into the braking position in which they protrude further from their respective bores than in the rest position. This sliding causes the tension spring to stretch. When braking is interrupted, the tension spring restores the elastic potential energy accumulated during braking so as to return the guide pin to the rest position and consequently cause the caliper to slide into the rest position.Depending on the embodiments, the spring is fixed to the bore either directly or by means of a connecting member.

[0013] According to one embodiment, the end of the guide pin present in the bore and / or the end of the bore to which the tension spring is fixed has a fixing hole intended to receive the end of the tension spring which is fixed to the guide pin or to the bore so as to fix the tension spring to the guide pin and / or to the bore. This is a simple, economical and space-saving means of establishing a secure connection between the tension spring and the bore and / or the guide pin. It is understood for example that, according to one embodiment, a free end of the tension spring is introduced into the fixing hole with a predetermined angle and depth making it possible to ensure the fixing from the tension spring to the bore or guide pin.

[0014] According to one embodiment, the end of the guide pin present in the bore and / or the end of the bore to which the tension spring is fixed has an annular groove intended to receive the end of the tension spring which is fixed to the guide pin or to the bore so as to fix the tension spring to the guide pin and / or to the bore. This is also a simple, economical and space-saving means of establishing a secure connection between the tension spring and the bore and / or the guide pin. For example, according to one embodiment, the end of the spring has a substantially annular portion intended to be received in the annular groove so as to fix the tension spring to the bore and / or to the guide pin.

[0015] Advantageously, the disc brake further comprises a clipping member fixed to the end of the spring which is fixed to the bore, the clipping member being intended to cooperate with a groove provided in the end of the bore so as to clip the tension spring to the bore. This is a simple means of fixing the spring in the bore. For example, when the guide pin is first inserted into the bore, the clipping member clips at one end of the bore comprising complementary fixing means intended to cooperate with the clipping member to fix the tension spring in the bore.

[0016] Preferably, a stop member extends axially projecting from the end of the guide pin present in the bore, the stop member being intended to come into abutment against the clipping member so as to prevent the tension spring from being compressed so that at least some of its turns are contiguous. Thus, it is advantageously simply prevented that the spring cannot be compressed to its maximum compression level, which would risk damaging it and impairing its function.

[0017] According to one embodiment, the elastic return means comprise an elastomer mass fixed on the one hand to one end of the bore and on the other hand to one end of the guide column which is present in the bore. This is an inexpensive and simple return means to implement.

[0018] The invention also relates to a vehicle comprising at least one disc brake as described above. Brief description of the figures

[0019] The invention will be better understood on reading the following description given solely by way of non-limiting example and made with reference to the appended drawings in which:

[0020] [Fig-1] is a top view of a vehicle according to the invention;

[0021] [Fig.2] is a perspective view of a disc brake according to a first embodiment lization of the invention;

[0022] [Fig.3] is an exploded perspective view of a guide column, return means and a clipping member included in the disc brake of [Fig.2];

[0023] [Fig.4] is a sectional view of a portion of the disc brake of [Fig.2] shown in the rest state (A) and in the braking state (B);

[0024] [Fig.5] is a view of an enlargement of the frame C shown in [Fig.4];

[0025] [Fig.6] is a sectional view of a guide column, return means and a clipping member according to a second embodiment of the invention.

[0026] [Fig.7] is a sectional view similar to [Fig.5] according to a third embodiment of the invention. Detailed description

[0027] Figures 1 to 5 show a first embodiment of the invention, [Fig.6] shows a second embodiment of the invention and [Fig.7] shows a third embodiment of the invention.

[0028] [Fig. 1] represents a vehicle, here a motor vehicle 1, according to the invention, comprising at least two disc brakes 2, here four in number, equipping each wheel 3 of the motor vehicle 1.

[0029] The disc brake 2 according to the invention is intended to equip any type of vehicle, for example motor vehicles of the passenger car type, SUV (English acronym for "Sport Utility Vehicles"), two-wheelers (in particular motorcycles), airplanes, industrial vehicles chosen from vans, "Heavy Goods Vehicles" - that is to say subways, buses, road transport vehicles (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering vehicles -, or other transport or handling vehicles. The invention also applies to non-motorized vehicles such as in particular a trailer, a semi-trailer or a caravan.

[0030] [Fig. 2] represents the disc brake 2 which is of the floating caliper disc type. Thus, it conventionally comprises a caliper 4 mounted sliding relative to a yoke 5 fixed relative to the motor vehicle 1. The caliper 4 slides between a rest position and a braking position. The disc brake 2 further comprises at least two brake pads (not shown) intended to cooperate by friction respectively with opposite faces of a disc integral in rotation with one of the wheels 3 of the motor vehicle 1 in order to carry out the braking.

[0031] In the present case, the disc brake 2 comprises an electric motor 6 intended to provide a clamping force to a clamping member (not shown), formed for example by a piston, in order to move the brake pads towards the disc so that the linings of the brake pads come into contact with the disc and grip it to perform braking. Alternatively, the clamping force is provided by a hydraulic actuator. Conventionally, in the first stage of braking, the clamping member is moved by the electric motor 6 until the inner brake pad comes into contact with the disc. The electric motor 6 then continues to provide a clamping force causing the caliper 4 to slide relative to the yoke 5 so as to move from the rest position to the braking position. This sliding moves the caliper 4 away from the yoke 5, thus bringing the outer brake pad closer to the disc until the two brake pads grip the disc to perform braking.

[0032] The disc brake 2 further comprises two guide columns 7 secured to the caliper 4 and each intended to cooperate with a respective blind bore 8 provided in the yoke 5 in order to guide the sliding of the caliper 4 relative to the yoke 5 (see [Fig. 3]). The guide columns are also called guide pins. Each guide column 7 has the general shape of a column and comprises a stop member 9 extending projecting from a distal end. A fixing orifice 10 is provided at the distal end of the guide column 7. More particularly, the fixing orifice 10 is provided on a lateral face of the stop member 9. According to other embodiments, the fixing orifice 10 is provided elsewhere on the guide column 7, for example at the level of a side wall of the distal end of the guide column 7 to the exclusion of the stop member 9.The proximal end of each guide post 7 has a fixing face 11 allowing the guide post 7 to be fixed to the bracket 4 by known means. For example, the fixing face 11 comprises a threaded hole (not shown) intended to cooperate with a fixing screw (not shown) to fix the guide post 7 to the bracket 4. According to other embodiments, the number of guide posts 7 is different, for example between three and six.

[0033] Each guide pin 7 is movable in translation in its bore 8 between a braking position (FIG. 4B) and a rest position (FIG. 4A) in which the guide pin 7 is further retracted into the bore 8 than in the braking position. In other words, in the braking position, each guide pin 7 is further out of the bore than in the rest position. It is understood that the braking and rest positions of the guide pins 7 correspond respectively to the braking and rest positions of the caliper 4.

[0034] The brake 2 comprises, inside each bore 8, means for elastically returning the guide column 7 to the rest position (figures 3 to 5). According to an alternative embodiment, only one of the bores comprises means for elastically returning the guide column 7 to the rest position.

[0035] According to the first embodiment, the elastic return means of the column 7 guide springs in the rest position are formed by a traction spring 12 (figures 3 to 5). Each traction spring 12 is fixed by its ends on the one hand to the blind end of the bore 8 in which it is located and on the other hand to the distal end of the guide pin 7 present in this bore 8 (figures 4 and 5). The means of fixing the traction spring 12 to the bore 8 and to the guide pin 7 varies according to the embodiments.

[0036] In the present case, the proximal end of each traction spring 12 is fixed to the guide column 7 by being introduced into the fixing orifice 10 ([Fig. 3]). The complementarity of shape between the proximal end of the traction spring 12 and the fixing orifice 10 as well as the insertion angle allow a simple and inexpensive fixing.

[0037] The distal end of the traction spring 12 is fixed to the bore 8 by means of a clipping member 13 (FIGS. 3 to 5). The clipping member 13 has the general shape of a disc from which radially extend clipping tabs 14, four in number in the present embodiment. The clipping member 13 has at its side wall a fixing orifice 15 intended to receive the distal end of the traction spring 12 so as to fix the traction spring 12 to the clipping member 13. According to other embodiments, the fixing of the traction spring 12 to the clipping member 13 is carried out differently, for example by gluing or welding. When the guide pin 7 is first inserted into the bore 8, the clipping tabs 14 are folded axially by friction against the walls of the bore 8 while the guide pin 7 travels through the bore 8.During this path, the friction between the wall of the bore 8 and the clipping member 13 is generally sufficiently significant to cause compression of the tension spring 12. During this compression, the distal end of the guide pin 7, and more particularly its stop member 9, comes into abutment against a proximal face of the clipping member 13. The stop member 9 is dimensioned such that it is sufficiently long to come into abutment against the clipping member 13 in order to prevent the tension spring 12 from being compressed until its turns are joined. The risk of damage to the tension spring 12 is thus reduced. According to other embodiments, the disc brake 2 does not comprise a clipping member. The spring is then, for example, directly fixed in the bore, for example via a fixing orifice provided in the bore. .

[0038] The blind end of the bore 8 comprises an annular groove 16 configured so that, when the clipping member 13 reaches the level of the annular groove 16, the space provided by the latter is sufficient to allow the clipping tabs 14 to extend radially, thus allowing the clipping member 13 to be clipped, and therefore also of the guide column 7 to which it is fixed via the traction spring 12, to the bore (see [Fig.5]).

[0039] An example of operation of the disc brake 2 as described previously is described below with reference to [Fig. 4].

[0040] Figure 4A describes the disc brake 2 according to the invention in the rest position. Thus, the caliper 4 and the guide pin 7 are in the rest position and the traction spring 12 is not stressed. During braking, as explained previously, the caliper 4 slides relative to the frame 5 so as to move away from the latter by a distance D until reaching a braking position shown in Figure 4B. During this sliding, each guide pin 7 stretches the traction spring 12 to which it is fixed by this same distance D so that the traction spring 12 accumulates elastic potential energy. When braking is interrupted, this elastic potential energy is restored in the form of kinetic energy which elastically returns the guide pins 7 to the rest position by causing them to slide in their respective bores 8 (Figure 4A).At the same time, the caliper 4 which is integral with the guide columns 7 is also returned to the rest position. As a result, the brake pads are moved so as to be away from the disc, thus avoiding or reducing any residual braking.

[0041] A second embodiment of the invention is shown in [Fig. 6]. This embodiment differs from the first embodiment only with respect to the features mentioned below.

[0042] The second embodiment of the invention differs from the first embodiment with regard to the attachment of the traction spring 12 to the clipping member 13 and to the guide column 7.

[0043] Thus, according to this second embodiment, the guide posts 7 and the clipping members 13 do not include a fixing orifice 10, 15. Instead, the distal end of each guide post 7 has an annular groove 17 and the proximal face of each clipping member 13 also has an annular groove 18. Each of these annular grooves 17, 18 is intended to receive respectively one of the ends of the traction spring 12 so as to fix the traction spring 12 to the guide post 7 and to the clipping member 13. According to this second embodiment, the guide posts 7 do not include a stop member 9. According to an alternative embodiment, the guide posts 7 according to this second embodiment include a stop member 9. The operation of the disc brake 2 remains identical to that described for the first embodiment.

[0044] A third embodiment of the invention is shown in [Fig. 7]. This embodiment differs from the first embodiment only with respect to the features mentioned below.

[0045] According to this third embodiment, the elastic return means of the guide columns 7 in the rest position are not formed by a traction spring 12 but by a mass 19 made of elastomer material. Each elastomer mass 19 is fixed on the one hand to the blind end of the bore 8, and on the other hand to the distal end of the guide column 7. This elastomer mass 19 has the same elastic return function as that fulfilled by the traction spring 12 described in the first embodiment. Each elastomer mass 19 is fixed to the bore 8 or the guide column 7 by any suitable means, for example by gluing. It is understood that the presence of the clipping member 13 is not necessary. This clipping member 13 is however present according to an alternative embodiment.According to the embodiments, any elastomer material capable of fulfilling the function of elastic return of the guide columns 7 to the rest position is used.

[0046] The invention is not limited to the embodiments presented and other embodiments will become clear to those skilled in the art. It is in particular possible to provide that the bores 8 formed in the stirrup 4 are not blind. List of references

[0047] 1: vehicle 2: brake 3: wheel 4: stirrup 5: screed 6: electric motor 7: guide column 8: bore 9: stop member 10: guide column fixing hole 11: fixing face 12: traction spring 13: clipping organ 14: clipping tab 15: fixing hole for the clipping member 16: annular groove of the bore 17: annular groove of the guide column 18: annular groove of the clipping member 19: mass of elastomeric material

Claims

Claims

1. Disc brake (2) for a vehicle (1), comprising: - a fixed yoke (5), - a caliper (4) mounted to slide relative to the yoke (5) between a rest position and a braking position, - at least two guide columns (7) integral with the caliper (4) and each intended to cooperate with a respective bore (8) provided in the yoke (5) in order to guide a sliding of the caliper (4) relative to the yoke (5), each guide column (7) being movable in translation in its bore (8) between a braking position and a rest position in which the guide column (7) is further retracted into the bore (8) than in the braking position, in which the brake comprises, inside at least one of the bores (8), means (12, 19) for elastically returning the guide column (7) to the rest position,characterized in that the elastic return means comprise a traction spring (12) fixed by its ends on the one hand to one end of the bore (8) and on the other hand to one end of the guide pin (7) present in the bore (8), or in that the elastic return means comprise an elastomer mass (19) fixed on the one hand to one end of the bore (8) and on the other hand to one end of the guide pin (7) which is present in the bore (8).,

2. Disc brake (2) according to claim 1, comprising, inside each bore (8), means (12, 19) for elastically returning the guide pin (7) to the rest position.

3. Disc brake (2) according to claim 1 or 2, in which the bores (8) are blind.

4. A disc brake (2) according to any one of the preceding claims, wherein the end of the guide pin (7) present in the bore (8) and / or the end of the bore (8) to which the tension spring (12) is fixed has a fixing hole (10) intended to receive the end of the tension spring (12) which is fixed to the guide pin (7) or to the bore (8) so as to fix the tension spring (12) to the guide pin (7) and / or to the bore (8).

5. A disc brake (2) according to any preceding claim, wherein the end of the guide pin (7) present in the bore (8) and / or the end of the bore (8) to which the tension spring (12) is fixed have an annular groove (17) intended to receive the end of the tension spring (12) which is fixed to the guide pin (7) or to the bore (8) so as to fix the tension spring (12) to the guide pin (7) and / or to the bore.

6. A disc brake (2) according to any one of the preceding claims, further comprising a clipping member (13) fixed to the end of the traction spring (12) which is fixed to the bore (8), the clipping member (13) being intended to cooperate with a groove (16) formed in the end of the bore (8) so as to clip the traction spring (12) to the bore (8).

7. Disc brake (2) according to claim 6, in which a stop member (9) extends axially projecting from the end of the guide pin (7) present in the bore (8), the stop member (9) being intended to come into abutment against the clipping member (13) so as to prevent the tension spring (12) from being compressed so that at least some of its turns are contiguous.

8. Vehicle (1) characterized in that it comprises at least one disc brake (2) according to any one of the preceding claims.

Images