Disc brake, in particular for motor vehicle

Abstract

The invention relates to a disc brake (F) comprising a caliper (E) having a fixed brake pad (P1) and a brake pad (P2) opposite each other, said brake pad (P2) being movable relative to the caliper (E); and a mechanism for actuating the movable brake pad (P2), the mechanism comprising a screw / nut system and means for transmitting the rotational movement of the drive pinion (5) to the screw / nut system to actuate the movable brake pad (P2). The invention is characterized in that the screw / nut system is mounted in a recess (L) made in the caliper (E), in which recess (L) the screw (1) of the screw-nut mechanism is mounted in a translational locking manner and can be rotated by means of a transmission device, and in that recess (L) the nut (2) is mounted in a rotationally locking manner and translates along the screw (1) during rotation of the screw (1), translation of the nut (2) in a first direction enables translation of the movable brake pad (P2) towards the fixed brake pad (P1) and translation of the nut (2) in an opposite direction enables translation of the movable brake pad (P2) away from the fixed brake pad (P1).

Description

[0001] This invention relates to a disc brake, particularly for motor vehicles, comprising a caliper capable of traversing sectors of a brake disc integral with the vehicle's wheels to position brake pads on each side of the disc, and having means for controlling the clamping of the brake pads onto the disc. Such disc brakes include calipers having fixed brake pads opposite each other and brake pads movable relative to the caliper, and the disc brake includes a mechanism for actuating the movable brake pads, the mechanism comprising a screw / nut system and means for transmitting rotational motion from a drive shaft to the screw / nut system to actuate the movable brake pads. Background Technology

[0002] In disc brakes, the caliper is constrained to rotate with the vehicle, for example, with the short axle that forms the wheel hub. The caliper typically comprises two arms connected by an arch and spans a sector of the brake disc, which is integral with the wheel, with one arm on each side of the disc. The caliper uses a pair of friction pads (i.e., brake shims), one on each side of the disc, to clamp the brake disc between its arms. During braking, these brake shims are clamped onto the brake disc by the action of one or more brake pistons. When used as a service brake, these brake pistons are actuated by hydraulic pressure; when used as a parking brake, they are driven by an electromechanical device. This clamping generates friction between the brake shims and the brake disc, dissipating the vehicle's kinetic energy as heat, thereby generating braking power.

[0003] Service braking functions include slowing down a moving vehicle and, if necessary, bringing it to a complete stop. In addition to service braking, these disc brakes can also be used for emergency braking and / or parking braking functions.

[0004] In the case where a disc brake has an electromechanical device for actuating the brake, the electromechanical device includes, on the one hand, a screw-nut assembly, and on the other hand, an electric gear motor assembly for bidirectionally rotating the nut of the screw-nut assembly. Such a disc brake is described, for example, in FR-A-3 116 576.

[0005] The caliper in this document has two arms, one with a fixed brake pad and the other with a movable brake pad, which are arranged opposite each other. The movable brake pad is displaced toward the fixed part by an electromechanical actuator with a ball screw / nut system and an interface for controlling the rotation of the motor.

[0006] The nut is fixedly mounted in a recess on the caliper arm. The nut is rotated by a motor's rotation control interface, which in turn generates a translational displacement of the screw. One end of the screw is coupled to a movable brake pad.

[0007] Therefore, rotating the nut in one direction causes the screw extending from the caliper arm to translate, thereby moving the movable brake pad toward the fixed brake pad to control brake disc clamping; rotating the nut in the opposite direction causes the screw to translate in the opposite direction, thereby moving the movable brake pad away to control release.

[0008] However, the above-mentioned type of brake is not only complex in structure, but also relatively large, especially at the interface between the drive shaft and the nut.

[0009] Therefore, the object of this invention is to provide a disc brake of this type that has a simpler structure and thus occupies less space.

[0010] This invention relates to a disc brake comprising a caliper having a fixed brake pad and a movable brake pad opposite to each other, and a mechanism for actuating the movable brake pad, the mechanism comprising a screw / nut system and means for transmitting rotational motion from a drive pinion to the screw / nut system to actuate the movable brake pad, characterized in that the screw / nut system is mounted in a recess formed on the caliper, the screw of the screw-nut mechanism is non-translatably mounted in the recess and rotatable by a transmission, while the nut is non-rotatably mounted in the recess and translates along the screw when the screw rotates, the translation of the nut in a first direction enabling the movable brake pad to translate toward the fixed brake pad, and the translation of the nut in the opposite direction enabling the movable brake pad to move away from the fixed brake pad.

[0011] Therefore, advantageously, the rotation of the non-translatable screw, driven by the drive pinion, results in the translational displacement of the non-rotatable nut. Since the screw is the element in the screw-nut mechanism driven by the drive pinion, the device required to transmit the rotation of the drive pinion to the screw requires fewer and smaller components than the device required to transmit the rotation of the drive pinion to the nut.

[0012] Therefore, the brake according to the invention has a simpler, more compact structure and is thus less expensive.

[0013] The brake includes a caliper with two arms defining a clearance between them, such that the brake is mounted overlappingly on a brake disc integral with the wheel. The sectors of the brake disc are thus accommodated between the arms of the caliper, each arm carrying a brake pad. One of the brake pads (referred to as a movable brake pad) can be displaced relative to the other brake pad (referred to as a fixed brake pad) during clamping or releasing actions, translating along an X-axis perpendicular to the brake disc clamped between the brake pads.

[0014] Therefore, one arm of the caliper includes a recess in which the screw / nut system of the movable brake pad drive mechanism is mounted. One end of the cylindrical recess, which has a circular cross-section, is open and leads to the space between the arms, while the other end at least partially houses a device for transmitting rotation of the drive pinion to the screw.

[0015] Therefore, the recess has at least one hole whose size is complementary to that of the nut of the screw / nut system, the hole including a fastening device complementary to the fastening device provided on the nut, such that the nut can be non-rotatably mounted in the recess and translated along the recess.

[0016] Therefore, these mounting devices include, for example, at least one axial rib extending along the longitudinal axis of the nut on the outer wall of the nut, and a corresponding axial groove formed in the recessed wall of the fixing member. The axial rib of the nut can be inserted into the axial groove formed in the recessed wall, thereby locking the nut in the recess to prevent its rotation, but allowing it to translate along the groove. It is conceivable that the rib is located on the recessed wall and the groove is located on the nut.

[0017] The means for transmitting the rotational motion of the drive pinion to the screw / nut system is also housed in the recess. These transmission means consist sequentially of the drive pinion, planetary carrier, and ring gear, starting from the drive shaft. The ring gear is integral with both the planetary carrier and the screw of the screw / nut system. Therefore, the ring gear is integrally formed with the screw, for example, constituting one end of the screw, the other end of which is inserted into the nut. Preferably, the screw / nut system is a ball screw / nut system. The cover covers the motor and includes means for controlling the motor.

[0018] Therefore, advantageously, the nut is preferably in the form of a cylindrical sleeve surrounding the screw, having threads on its inner wall that engage with the screw, and is locked in a recess to prevent rotation. The nut translates under the action of the screw being rotated by the drive shaft. During translation, the end of the nut extends into the space between the caliper arms, abutting against the movable brake pad and enabling the brake pad to move.

[0019] Preferably, the end of the nut is fitted with a cap in a sealing manner. The capped nut acts as a piston, translated and displaced by the screw, pressing against the movable brake pad towards the fixed brake pad in one direction of screw rotation, and retracting in the opposite direction of rotation. The cylindrical nut with the end cap thus becomes piston-shaped, enabling it to apply a more evenly distributed axial thrust to the movable brake pad.

[0020] A sealing bellows is also fixed between the periphery of the recess and the cover to ensure that the recess remains sealed when the piston nut is displaced.

[0021] Advantageously, the cover has a cylindrical skirt that engages with the end of the nut and, when the movable brake pad is in the released position and spaced apart from the fixed brake pad, the skirt seals against the periphery of the recess. Meanwhile, a sealing bellows is fixed between the caliper (around the periphery of the recess) and the cover, such that the bellows maintains the seal of the recess when the nut is driven toward the brake pad clamping position.

[0022] Advantageously, the screw / nut system, cap, and sealing bellows are assembled into a module that can be inserted into a recess made in the caliper.

[0023] The movable brake pads are either installed as part of the nut or installed independently.

[0024] The brake according to the invention reduces the space required for the interface between the drive pinion and the screw / nut system, which also reduces the number of required components. Furthermore, since the nut behaves like a hydraulic piston, the screw and interface are not subjected to radial forces.

[0025] The present invention also relates to a motor vehicle equipped with a disc brake according to the present invention.

[0026] The present invention also relates to a method of manufacturing a brake according to the invention, wherein a through hole is made on one of the arms of the caliper to form a recess leading to the space between the arms, a screw / nut system is mounted in the recess, one end of the screw is connected to a means for transmitting rotational motion from a drive pinion connected to an electric motor, and the end of the nut is secured to a movable brake pad.

[0027] The invention will now be described in more detail with reference to the accompanying drawings, which show:

[0028] [ Figure 1 A longitudinal sectional view of the disc brake according to the present invention;

[0029] [ Figure 2 ] according to Figure 1 A side perspective view of the screw / nut system of the brake.

[0030] [ Figure 3 ] according to Figure 2 A longitudinal sectional view of the screw / nut system;

[0031] [ Figure 4 A perspective view of the disc brake according to the present invention; and

[0032] [Figure 5] Top view of a vehicle equipped with a brake according to the present invention.

[0033] from Figure 1As can be seen, the present invention relates to a disc brake F, which includes a caliper E designed to span a sector of a brake disc, for example, integrally formed with the vehicle wheel on the wheel hub.

[0034] The caliper E includes two arms B1, B2, which define a space E1 in which one and another brake pads P1, P2, located on either side of the brake disc sector, extend relative to each other.

[0035] One arm B1 of the caliper (also known as the nose of the caliper E) carries the fixed brake pad P1, and the second arm B2 carries the movable brake pad P2.

[0036] Arm B2 includes a through-hole defining a recess L in which a screw / nut system actuated by a geared motor is housed. The geared motor is completely coaxial with the screw and located entirely at the rear of the screw, i.e., on the side opposite to the brake pad relative to the screw thread, thus allowing the screw to be made as a solid part without an inner bore. The screw / nut system preferably comprises a ball screw / nut assembly, including a screw 1, a nut 2 forming the ball screw, and balls 3 inserted into the threads of the screw 1 and nut 2. The ball nut operates by recirculating the balls within the thickness of the nut, the recirculation path being radially outward-opening and covered by a ring, the ends of the recirculation path being defined by pins radially inserted into the nut.

[0037] Therefore, screw 1 and nut 2 extend into the recess L. Screw 1 is rotatably mounted under the action of a gear motor and cannot be translated, while nut 2 is non-rotatably mounted in the recess L and can be translated within the recess L under the rotation of screw 1.

[0038] The device for transmitting the rotational motion of the drive pinion 5 enables the screw 1 to rotate, and this device, for example, starting from the drive shaft 4, consists of the following components in sequence: the drive pinion 5 forming the sun gear, a fixed gear ring 6, and a movable gear ring 7, which is formed to open towards the rear of the screw and surround the planetary gears. The gear ring 7 is integral with the screw 1. Therefore, the gear ring 7 is integrally formed with the screw 1, for example, by forming the end of the screw 1.

[0039] The planetary gear 8 is radially positioned between the drive pinion 5, the fixed gear ring 6, and the movable gear ring 7, for example, to ensure that the motion transmitted inside the brake F is irreversible.

[0040] The drive pinion 5 is fastened to the drive shaft 4. The planetary gear 8 meshes inward with the drive pinion 5 and outward with both the fixed gear ring 6 and the gear ring 7. This forms a differential planetary gear system, in which the drive pinion 5 drives the gear ring 7 to rotate at a high transmission ratio. The screw 1 is fastened to the gear ring 7 and constrained to rotate with it.

[0041] Therefore, when the gear ring 7 rotates under the action of the drive pinion 5, the screw 1 also rotates. The nut 2, which is held in the recess L and cannot rotate, then translates along the screw 1.

[0042] The end of the nut 2 is tightly fitted with a cover 9 that is integral with the movable brake pad P2. Therefore, in the first rotational direction of the screw 1, the nut 2 translates and extends into the space E1, translating the brake pad P2 toward the fixed brake pad P1 to clamp the brake disc.

[0043] In the opposite direction to the rotation of screw 1, nut 2 retracts and translates into recess L, causing movable brake pad P2 to move away from fixed brake pad P1 in the release direction.

[0044] Therefore, a cover 9 is installed at the end of the nut 2 leading to the space E1 of the caliper E. The cover 9 has a cylindrical skirt 9a that is inserted around the nut 2. In the brake release position, the end of the skirt 9a preferably seals against the periphery of the recess L of the arm B2. When the nut 2 translates in the direction of brake application, the skirt 9a of the cover 9 no longer abuts against the arm B2.

[0045] To maintain the seal of the recess L, the sealing bellows 10 is fastened between the arm B2 of the caliper E and the cap 9. Therefore, when the nut 2 is actuated in the braking direction, the end of the nut 2, which mates with the cap 9 fastened to the movable brake pad P2, drives the movable brake pad toward the fixed brake pad P1. The skirt 9a of the cap no longer rests against the arm B2, and the sealing bellows 10 is stretched, thereby maintaining the seal.

[0046] Preferably, arm B2 has ribs 11 around the periphery of recess L to form a shoulder 11a, the end of skirt 9a of cover 9 is accommodated on the shoulder 11a, and the shoulder 11a also enables one end of sealing bellows 10 to be fastened and the other end of bellows 10 to cover 9.

[0047] The cover 9 is mounted on the nut, and a sealing washer 12 is inserted between most of the nut 2 and the skirt 9a of the cover 9.

[0048] At the other end of the recess L, the hole preferably has a larger diameter, in which a device for transmitting the rotational motion of the drive pinion 5 to the screw 1 is housed, such as a fixed gear ring 6 and a movable gear ring 7. Therefore, the movable gear ring 7 is constrained to rotate together with the screw 1. Figure 3 As shown, the toothed ring 7 forms the end of the screw 1.

[0049] A through hole is formed in arm B2 of caliper E to create a recess L leading to the space E1 between arm B2 and arm B1. A screw / nut system is installed in the recess, with the end of nut 2 coupled to cap 9 and brake pad P2, and then a sealing bellows 10 is installed.

[0050] The device for transmitting rotary motion is installed at the end of the hole. The end of the screw 1, which is in the form of a gear ring 7, meshes with the planetary gear 8. The outer side of the planetary gear 8 meshes with the inner side of the fixed gear ring 6. The inner side of the planetary gear 8 meshes with the drive pinion 5. The drive pinion 5 is then connected to the drive shaft 4 of the motor M. The motor M is installed in the housing B that is fastened to the caliper E, located at the outlet of the recess L, and is closed with a protective cover C.

[0051] Therefore, as Figure 4 As shown, the brake F according to the present invention is installed in vehicle V ( Figure 5 Different variations or additional options, such as parking brake function, can be used on each wheel R.

[0052] Of course, the present invention is not limited to the above examples, and many modifications can be made to these examples without departing from the scope of the present invention.

[0053] Figure Labels

[0054] F disc brake

[0055] E caliper

[0056] B1, B2 caliper arms

[0057] Space between E1 caliper arms

[0058] P1 Fixed brake pad

[0059] P2 Removable Brake Pad

[0060] L recess

[0061] 1. Screw

[0062] 2 nuts

[0063] 3 ball bearings

[0064] 4 drive shafts

[0065] 5. Drive pinion

[0066] 6. Fixed gear ring

[0067] 7. Movable gear ring

[0068] 8 Planetary Gears

[0069] 9. Cover

[0070] 9a Cover skirt hem

[0071] 10 Sealed bellows

[0072] 11. Fastening Ribs

[0073] 11a Shoulder area with fastened ribs

[0074] 12 Sealing gaskets

[0075] M motor

[0076] B. Motor housing

[0077] C Protective cover

[0078] R wheel

[0079] V vehicle

Claims

1. A disc brake (F) comprising a caliper (E) having fixed brake pads (P1) and brake pads (P2) opposite to each other, the brake pads (P2) being movable relative to the caliper (E), the disc brake (F) further comprising a mechanism for actuating a movable brake pad (P2), the mechanism comprising a screw / nut system and means for transmitting rotational motion from a drive shaft (4) to the screw / nut system to actuate the movable brake pad (P2), the screw / nut system and the means being coaxially mounted to each other. Its features are, The screw / nut system is mounted in a recess (L) formed in the caliper (E). The screw (1) of the screw-nut mechanism is non-translatably mounted in the recess (L) and is rotatable by the transmission device. The nut (2), which is non-rotatably mounted in the recess (L), is translatable along the screw (1) during the rotation of the screw (1). The translation of the nut (2) in a first direction allows the movable brake pad (P2) to translate toward the fixed brake pad (P1), and the translation of the nut (2) in the opposite direction allows the movable brake pad (P2) to move away from the fixed brake pad (P1).

2. The disc brake (F) according to claim 1, characterized in that, One of the arms (B1, B2) of the caliper (E) includes the recess (L), in which the screw / nut system is mounted. The recess (L) is cylindrical with a circular cross-section, one end of which is open to the space (E1) between the arms (B1, B2), and the other end at least partially accommodates means for transmitting the rotation of the drive pinion (5) to the screw (1).

3. The disc brake (F) according to claim 1 or 2, characterized in that, The recess (L) therefore has at least one hole whose size is complementary to that of the nut (2) of the screw / nut system, the hole including a fastening device complementary to the fastening device provided on the nut, such that the nut (2) can be non-rotatably mounted in the recess (L) and translated.

4. The disc brake (F) according to any one of claims 1 to 3, characterized in that, These fastening devices include at least one axial rib extending along the longitudinal axis of the nut (2) on the outer wall of the nut (2), and a corresponding axial groove formed on the wall of the recess (L), the axial rib of the nut (2) being able to be inserted into the axial groove formed on the wall of the recess (L).

5. The disc brake (F) according to any one of claims 1 to 4, characterized in that, The device for transmitting the rotational motion of the drive pinion to the screw / nut system is also housed in the recess (L) and consists of a drive pinion (5) starting from the drive shaft (4), a fixed gear ring (6), and a movable gear ring (7) integral with the screw (1) of the screw / nut system.

6. The disc brake according to any one of claims 1 to 5, characterized in that, The geared motor transmission device is located entirely at the rear of the screw, that is, on the opposite side of the brake pad relative to the screw thread.

7. The disc brake (F) according to any one of claims 1 to 4, characterized in that, The device for transmitting the rotational motion of the drive pinion to the screw / nut system is also housed in the recess (L) and consists of the drive pinion (5) starting from the drive shaft (4), the planet carrier (6), and the gear ring (7) which is integral with the planet carrier (6) and the screw (1) of the screw / nut system.

8. The disc brake (F) according to any one of claims 5 to 7, characterized in that, The gear ring (7) is integrally formed with the screw (1), so that it is formed by one end of the screw (1), and the other end of the screw (1) is inserted into the nut (2).

9. The disc brake (F) according to any one of claims 6 to 8, characterized in that, The screw / nut system consists of a ball screw / nut system.

10. The disc brake (F) according to any one of claims 1 to 9, characterized in that, The nut (2) is in the form of a cylindrical sleeve surrounding the screw (1), with threads on its inner wall, engaging with the threads of the screw (1), and locked in the recess to prevent rotation. The nut (2) is translated under the rotation of the screw (1), and the end of the nut (2) is inserted into the space (E1) between the arms (B1, B2) of the caliper (E) and abuts against the brake pad (P2).

11. The disc brake (F) according to claim 10, characterized in that, The nut (2) has a cap (9) that is sealed at its end.

12. The disc brake (F) according to claim 11, characterized in that, A sealing bellows (10) is also tightly fitted between the periphery of the recess (L) and the cover (9).

13. The disc brake (F) according to any one of claims 11 and 12, characterized in that, The screw / nut system, the cover (9), and the sealing bellows (10) are assembled into a module that can be inserted into the recess (L) formed in the caliper (E).

14. The disc brake according to any one of the preceding claims, characterized in that, The movable gear ring (7) is axially supported on the fixed gear ring (6) by a rolling bearing.

15. A motor vehicle equipped with a disc brake according to any one of claims 1 to 14.

16. A method for manufacturing a disc brake (F) according to any one of claims 1 to 14, the disc brake comprising a caliper (E) having fixed brake pads (P1) and brake pads (P2) opposite to each other, the brake pads (P2) being movable relative to the caliper (E), the disc brake further comprising a mechanism for actuating a movable brake pad (P2), the mechanism comprising a screw / nut system and means for transmitting rotational motion of a drive pinion (5) to the screw / nut system to actuate the movable brake pad (P2), characterized in that, A through hole is made on one of the arms of the caliper (E) to form a recess (L) leading to the space (E1) between the arms (B1, B2), and the screw / nut system is installed in the recess (L), one end of the screw (1) being coupled to a device for transmitting the rotational motion of a drive pinion (5) connected to an electric motor (M), and the end of the nut (2) being fastened to the movable brake pad (P2).

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