Electromechanically actuated brake caliper for disc brake

Abstract

An electromechanic ally actuated brake caliper (1) comprises a caliper body (3) and a pair of pads (7;7a,7b). The caliper body (3) has a motor housing (13) and an actuator housing (15). The brake caliper further comprises an actuator device (71), a transmission device (101), an electric motor (33), and a cover (19; 419).

Description

"ELECTROMECHANICALLY ACTUATED BRAKE CALIPER FOR DISC BRAKE"DESCRIPTIONField of the invention

[0001] The present invention relates to the field of electromechanical braking devices for decelerating or parking a vehicle . In particular, the obj ect of the present invention is a gearmotor assembly for a brake caliper of a disc brake for light or heavy vehicles or for motorcycles .Background of the invention

[0002] In a disc brake, the brake caliper is generally arranged straddling the outer peripheral edge of a brake disc suitable for rotating about a rotation axis A defining an axial direction X . In a disc brake, a radial direction R is also defined, substantially orthogonal to said axial direction X, and a tangential or circumferential direction C, orthogonal both to said axial direction X and to said radial direction R.

[0003] The brake caliper is constrained to a support structure which remains stationary with respect to the vehicle wheel, such as, for example, a knuckle of a vehicle suspension, a wheel hub of the vehicle or a fork. The brake caliper usually comprises a caliper body having two elongated portions arranged so as to face opposite brakingsurfaces of the brake disc, and a bridge connecting said two elongated portions . The caliper, when suitably actuated, presses the pads against the braking band, and the braking action is produced by the friction between the pads and the braking band of the brake disc .Prior art

[0004] Electromechanical systems for actuating the caliper are now widely used, provided with a gearmotor usually housed in the caliper body.

[0005] An example of an embodiment is described in International Application W0-A1-2023 / 166434 in the name of the Applicant . However, in the solution disclosed therein, the motor is housed in a dedicated motor housing, externally to the caliper body.Object of the invention

[0006] An obj ect of the present invention is to meet the compactness requirements of the sector, with particular reference to application in motorcycles, and at the same time to overcome the drawbacks of known solutions, especially with regard to the complexity of assembling the brake caliper .

[0007] Said purpose is achieved by a brake caliper according to claim 1. The dependent claims identify further advantageous embodiments of the invention.Brief description of the figures

[0008] The features and advantages of the gearmotor assembly according to the present invention will be apparent from the following description, given by way of example and not limitation, in accordance with the figures of the accompanying drawings, in which:- Figure 1 shows an electromechanically actuated brake caliper, according to one embodiment of the present invention;- Figure 2 represents a sectional view of a caliper body of the brake caliper of figure 1 ;- Figure 3 illustrates a motor of the brake caliper, in exploded view;- Figure 4 depicts a sectional view of the brake caliper; - Figure 5 is a sectional view of the motor of the brake caliper;- Figure 6 shows a detail of the brake caliper, with particular reference to a transmission device;- Figures 7a and 7b show winding insulators of the motor;Figure 8 depicts a stator, according to a further embodiment of the invention;- Figure 9 shows a still further embodiment of the present invention;Figure 10 represents a bearing, according to one embodiment of the present invention;- Figure 11 depicts a still further embodiment of thepresent invention.Description of the invention

[0009] With reference to the figures of the accompanying drawings, the numeral 1 denotes overall a brake caliper of an electromechanical disc brake for decelerating or parking vehicles, and in particular motor vehicles .

[0010] The brake caliper 1, which cooperates with a brake disc (not shown) , and in particular with an annular braking band of said brake disc, comprises a caliper body 3, monobloc or made of several parts mechanically integrally connected to one another, consisting of a front portion 3a, proximal to the brake disc and straddling it, and a rear portion 3b, contiguous to the front portion 3a and axially distal from the brake disc .

[0011] The brake caliper 1 further comprises at least one pin 5 supported by the caliper body 3, arranged with its axis substantially parallel to an axial direction X . Typically, two pins 5 are provided, circumferentially spaced .

[0012] The brake caliper 1 further comprises at least one pad 7 and preferably a pair of pads 7, for example a front pad 7a and a rear pad 7b, arranged mutually facing a region of the braking band and supported by said pins 5 so as to be axially translatable towards the braking band to clamp it between them.

[0013] The caliper body 3 is internally partially hollow and has an inner compartment 9, preferably formed in the rear portion 3b of the caliper body 3; the front portion 3a is preferably solid.

[0014] The inner compartment 9 is radially partitioned by a partition wall 11 of the caliper body 3 into a motor housing 13, distal from the rotation axis A of the brake disc, and an actuator housing 15, proximal to the rotation axis A of the brake disc .

[0015] The motor housing 13 is accessible from outside the caliper body 3, at the rear thereof, through a motor housing opening 14, and the actuator housing 15 is accessible from outside the caliper body 3, at the front thereof, that is from the pad side, through an actuator housing opening 16.

[0016] Inside the caliper body 3, the motor housing 13 and the actuator housing 15 are in communication through an inner gap 17, defined by an interruption or by the end of the partition wall 11.

[0017] The brake caliper 1 further comprises a removable cover 19 which closes the caliper body 3 at the rear, that is, it closes the rear portion 3b; in particular, the cover 19 closes the motor housing opening 14.

[0018] The cover 19 comprises a cover body 21 couplable to the caliper body 3, comprising an electrical connector 23,accessible from outside the brake caliper for the electrical connection of the brake caliper .

[0019] The cover body 21 has, on the inner face 25 facing the inside of the caliper body 3 when the cover 21 is applied to the caliper body 3, an electronic board 27 comprising a position sensor for detecting the angular position of a rotor and a plurality of electrical terminals 29, 31, for example low power terminals 29 for the supply of position sensors and position sensor signals, and high power terminals 31 for the supply of the motor phases .

[0020] The axial bulk of the electronic board 27 is axially overlapped to the axial bulk of the high power terminals 31 and of the fork-pocket system which will be described below. Advantageously, this configuration allows reducing the axial bulk of the caliper .

[0021] Preferably, the cover 19 is made by overmoulding.

[0022] The brake caliper 1 further comprises a motor 33 housed in the motor housing 13, and in particular in a rear zone 13b of said motor housing 13.

[0023] The motor 33 consists of a stator 35, provided with a lamellar pack 37, and a rotor 39 provided with a rotor pack 41 .

[0024] Preferably, the electrical power supply of the lamellar pack 37 of the stator 35 is implemented by means of an IDC ( Insulation Displacement Contact) system.

[0025] According to an embodiment, the IDC system provides three axial forks 43 connected on one side to the respective high power terminals 31 of the cover 19 and on the other side inserted into a respective pocket 44 of the stator 35; each pocket 44 is in turn connected to the winding of the lamellar pack 37 of the stator 35.

[0026] According to a variant embodiment, the IDC system provides blades capable of engaging fork connections of the cover .

[0027] Preferably, the stator 35 further comprises a pair of winding insulators 45, for example a front insulator 45a and a rear insulator 45b, on which the lamellar pack 37 is arranged; in particular, the rear insulator 45b carries the pockets 44 for the electrical connection.

[0028] According to a variant embodiment, the winding insulators are overmoulded onto the lamellar pack.

[0029] The stator 35 is keyed directly into the motor housing 13, onto a cylindrical stator keying surface 13' , partially placed on the partition wall 11 of the caliper body 3.

[0030] In other words, according to the invention, the stator is not housed in an enclosure, which is in turn mounted in the caliper body.

[0031] The presence of an enclosure for the stator, whether made of metallic or plastic material, as provided in some solutions of the prior art, entails certain drawbacks,including an increase in cost and in radial and axial bulk of the system.

[0032] Advantageously, instead, providing for the housing of the stator directly in the caliper body improves thermal dissipation of the motor due to the absence of interposed materials between the stator and the wall of the caliper body and, in general, reduces the component count needed for motor integration, such as 0-rings and fastening screws .

[0033] The rotor 39, provided with permanent rotor magnets 47, arranged coaxially inside the lamellar pack 37 of the stator 35, comprises a rotor shaft 49 having a motor axis K parallel to the axial direction X, on which the rotor pack 41 is mounted, and a front bearing 50 and a rear bearing 51 which rotatably support the rotor shaft 49, arranged respectively at a front end 49a and a rear end 49b of the rotor shaft 49.

[0034] According to a variant embodiment, the rotor is provided with surface permanent magnets .

[0035] The front bearing 50, axially retained in position between a shoulder of the rotor shaft and a corrugated spring 53, is supported in a bearing seat 57 of a bearing housing 55, preferably made of metallic material, for example of drawn sheet metal . The spring 53 is axially preloaded between said front bearing 50 and a preloadportion 59 of the bearing housing 55.

[0036] For example, the preload portion 59 is axially perforated and is crossed by the front end 49a of the rotor shaft 49 to operatively engage a transmission device which will be described later .

[0037] Advantageously, the spring 53 allows taking up axial play between the components of the system, allows setting a correct preload of the bearings and the minimum force that ensures the positional stability of the rotor under various application conditions, both thermal and vibrational .

[0038] At the rear, instead, the rear bearing 51 is supported in a bearing compartment 19' obtained in the cover 19, axially retained in position between a shoulder of the wall of the bearing compartment 19' and a shoulder of the rotor shaft 49.

[0039] At the front end 49a, the rotor shaft 49 is provided with a rotor pinion 61, formed in one piece with the rotor shaft 49 or applied to it so as to be rotationally integral, for torque transmission.

[0040] The brake caliper 1 further comprises an actuator device 71 for applying thrust on the pads 7 along a thrust axis J parallel to the axial direction X, that is, parallel to the motor axis K. The actuator device 71 is housed in the actuator housing 15 of the inner compartment 9 of thecaliper body 3.

[0041] The actuator device 71 comprises an actuator nut screw 73, rotatably supported inside the actuator housing 15, for example by means of a roller or needle cage 75, keyed onto a cylindrical actuator keying surface 15' , partially placed on the partition wall 11 of the caliper body 3 and preferably axially spaced from the stator keying surface 13' .

[0042] The actuator device 71 further comprises a toothed actuator wheel 77 , preferably with straight teeth, formed in one piece with the actuator nut screw 73 or applied to it so as to be rotationally integral, for example keyed, and an actuator screw 79, arranged inside the actuator nut screw 73 and actuatable in translation by it along said thrust axis J to move forward and press one of said pads 7, for example the rear pad 7b .

[0043] For example, the actuator nut screw 73 and the actuator screw 79 respectively form the nut and screw of a ball screw system for the translation of the actuator screw 79, also provided with a thrust bearing 81 for the nut and an anti-rotation pin 83 for the screw, engaged with a fixed bushing 85 arranged in the actuator housing 15.

[0044] According to a variant embodiment, the anti-rotation element is a shoulder of the caliper body proj ecting forexample from a protrusion 95 of the caliper body which penetrates into the actuator screw 79. According to a still further variant, the anti-rotation element is a separate element, applied to the protrusion 95.

[0045] Preferably, the actuator device 71 further comprises a force sensor 87 sensitive to the axial thrust exerted by the actuator nut screw 73, electrically connected to the electrical terminals 29, 31 of the cover 19.

[0046] Preferably, the fixed bushing 85 also supports the thrust bearing 81 and the force sensor 87.

[0047] Advantageously, the thrust bearing 81 and the force sensor 87 are axially arranged in overlap with the axial bulk of the actuator screw 79, to limit the axial bulk of the actuator device 71.

[0048] Furthermore, preferably, between the actuator screw 79 and the rear pad 7b there is interposed a joint 89, carried by the head of the actuator screw 79, and a thrust plate 91, supported by the joint 89, so as to discharge any radial reaction forces from the pad to the actuator screw 79.

[0049] Advantageously, this allows transmitting to the actuator screw 79 only axial reaction thrusts, preserving the correct operation of the screw-nut system.

[0050] At the rear, the actuator housing 15 is closed by a wall 3c of the caliper body 3, so that the actuator device71 remains confined between said wall 3c and the pads 7 ; preferably, the wall 3c has a hole for the passage of electrical connections of a force sensor towards the cover, provided with prepared pads .

[0051] The toothed wheel 77 is at least partially accessible from outside the actuator housing 15 through the inner gap 17, in order to create a functional interface with the transmission device which will be described below.

[0052] The brake caliper 1 further comprises a transmission device 101 for transmitting torque from the motor 33 to the actuator device 71. The transmission device 101 is housed in the motor housing 13, in a front zone 13a thereof, adj acent to the front portion 3a of the caliper body 3 .

[0053] The transmission device 101 comprises an epicyclic reduction gear coaxial with the rotor shaft 49, consisting of a sun gear formed by the rotor pinion 61, a plurality of planet gears 103, a planet gear carrier 105, and a crown 107, supported by the caliper body 3, for example keyed onto a cylindrical crown keying surface 13' ’ , partially placed on the partition wall 11 of the caliper body 3, preferably axially overlapped with the actuator keying surface 15' .

[0054] The transmission device 101 further comprises a geartrain, for example a pair of toothed wheels 109, 111,engaged at the input to the planet gear carrier 105 and at the output to the toothed actuator wheel 77 through the inner gap 17, to offset the torque action from the motor axis K to the thrust axis J.

[0055] The crown 107, preferably made in one piece, preferably of metallic material, for example hardened steel, comprises a main annular portion 113 that supports the planet gears 103 and has an outer side surface 113e knurled to allow its keying onto the crown keying surface 13' ’ , and a secondary portion 115, which extends axially rearward from the main portion 113 and supports by keying the bearing housing 55.

[0056] For assembling the brake caliper 1 according to the present invention, starting from the empty caliper body 3, the transmission device 101 is applied, and in particular the crown 107, followed by the bearing housing 55 in the crown 107 and the stator 37. Subsequently, the rotor 39 and the cover 19 are inserted. Finally, the actuator device 71 is mounted.Further embodiments of the invention

[0057] According to one embodiment of the invention, the transmission device comprises two or more epicyclic gear trains, with a single crown or different crowns for each gear train, arranged in series .

[0058] According to a further embodiment ( figure 8 ) , thestator is of the segmented type and is preferably provided with a busbar with welds for the electrical connection.

[0059] According to a still further embodiment ( figure 9) , the stator 235 comprises pins 293 axially protruding at the rear, which engage in a bearing housing 255, for example riveted and / or locked by plastic welding. According to a further example, the pins 293 are locked by a self-locking ring.

[0060] According to one embodiment ( figure 10) , the front bearing 350 has on the outer slewing ring 351 one or more O-rings 353 (a "creep-resistant" type bearing) to ensure grease tightness of the transmission device towards the motor, and to prevent wear between the outer slewing ring 351 and the bearing housing 355.

[0061] According to a further embodiment, a wave spring is arranged in the bearing compartment of the cover, acting on the rear bearing, of the traditional type or of the "creep-resistant" type . Advantageously, the wave spring compensates for axial play due to the coupling between the outer slewing ring of the rear bearing and the plastic material of the cover .

[0062] For example, the bearing compartment includes a comoulded steel bearing cap or a plastic material cap, paired with the rear bearing.

[0063] According to a still further embodiment ( figure 11 ) ,the cover 419 has a through hole at the rear bearing 451. The rear bearing 451 is axially locked, for example by means of a peripheral crimping 453, inside a bearing support 455 made of steel, co-moulded with the cover 419.

[0064] Advantageously, the hole through the cover 419 allows the keying of the inner slewing ring of the rear bearing 451 onto the rotor shaft 449 with a greater diametral size of said rear bearing compared to the other embodiments of the invention, since the electronic board 427 can be mounted downstream of the bearing assembly into the cover 419. The inner hole of the electronic board 427 has a smaller diameter than the outer diameter of the rear bearing 451 .

[0065] A closure cap 457 is arranged to close the hole of the cover 419, to ensure sealing against external agents . The fastening of the closure cap 457 is carried out by welding 459 between thermoplastic materials, such as ultrasonic welding, along the contact profile between the closure cap 457 and the cover 419.List of reference numerals1 - brake caliper3 - caliper body3a - front portion of the caliper body3b - rear portion of the caliper body5 - pin, 7a, 7b - pads- inner compartment1 - partition wall3 - motor housing3' - stator keying surface3' ’ - crown keying surface3a - front zone of the motor housing 3b - rear zone of the motor housing 4 - motor housing opening5 - actuator housing5' - actuator keying surface6 - actuator housing opening7 - inner gap9 - cover9' - bearing compartment1 - cover body3 - electrical connector5 - inner face of the cover body7 - electronic board9, 31 - electrical terminals3 - motor5 - stator7 - lamellar pack of the stator9 - rotor1 - rotor pack of the rotorforks- pocket, 45a, 45b winding insulators- rotor magnets- rotor shafta - front end of the rotor shaftb - rear end of the rotor shaft- front bearing- rear bearing- corrugated spring- bearing housing- bearing seat- preload portion of the bearing housing - rotor pinion- actuator device- actuator nut screw- roller or needle cage- toothed actuator wheel- actuator screw- thrust bearing- anti-rotation pin- fixed bushing- force sensor- joint- thrust plate- transmission device- planet gears- planet gear carrier- crown, 111 - toothed wheels- main portion of the crowne - outer side surface of the crown - secondary portion of the crown - stator- rotorb - rear insulator- rear bearing- bearing housing- pins- front bearing- outer race- O-ring- bearing housing- cover- electronic board- rotor shaft- rear bearing- chamfering- bearing support- closure cap459 - weldX - axial direction K - motor axisJ - thrust axis

Claims

1. CLAIMS1 . A electromechanically actuated brake caliper ( 1 ) couplable to a brake disc of a disc brake , comprising : a caliper body ( 3 ) having a front portion ( 3a ) , configured to be arranged straddling the brake disc, and a rear portion ( 3b ) axially contiguous to the front portion ( 3a ) ;- a pair of pads ( 7 ; 7a, 7b ) slidingly supported along an axial direction (X ) by the caliper body ( 3 ) to apply a braking action on the brake disc ;- wherein the caliper body ( 3 ) internally has an inner compartment ( 9 ) and a partition wall ( 11 ) which divides the inner compartment ( 9 ) into a motor housing ( 13 ) and an actuator housing ( 15 ) , said motor housing ( 13 ) and actuator housing ( 15 ) being in communication by means of an inner gap ( 17 ) through or at the end of the partition wall ( 11 ) ; - an actuator device ( 71 ) keyed into the actuator housing ( 15 ) , comprising an actuator screw ( 79 ) translatably actuatable along a thrust axis ( J) parallel to the axial direction (X ) for actuating the pair of pads while braking, said actuator device ( 71 ) being provided with a toothed actuator wheel ( 77 ) accessible from the motor housing ( 13 ) through said inner gap ( 17 ) ;- a transmission device ( 101 ) housed in a front zone ( 13a ) of the motor housing ( 13 ) , comprising an epicyclicreduction gear and at least one toothed wheel ( 109, 111 ) which engages the toothed actuator wheel (77 ) through said inner gap ( 17 ) ;- an electric motor (33) housed in a rear zone ( 13b) of the motor housing ( 13) , comprising a stator (35; 235) keyed into the rear zone ( 13b) and a rotor (39) having a motor axis (K) parallel to and spaced from the thrust axis (J) of the transmission device ( 101 ) and coaxial to the epicyclic reduction gear, said rotor being rotationally integral with a rotor pinion ( 61 ) which forms a sun gear for the epicyclic reduction gear;- a cover ( 19; 419) , applicable to the caliper body (3) for closing the inner compartment ( 9) at the rear, wherein said cover ( 19; 419) comprises an externally accessible electrical connector (23) for the electrical connection of the brake caliper, low power terminals (29) for sensors, and high power terminals (31 ) electrically connected to the stator for supplying the motor phases .

2. A brake caliper according to claim 1, wherein the motor housing ( 13) is externally accessible from the caliper body (3) , at the rear thereof, through a motor housing opening ( 14 ) for the insertion of the transmission device ( 101 ) and the motor (33) .

3. A brake caliper according to claim 2, wherein the motor housing opening ( 14 ) is closed by the cover (19; 419) .

4. A brake caliper according to any one of the preceding claims, wherein the actuator housing ( 15) is externally accessible from the caliper body (3) , at the front thereof, through an actuator housing opening ( 16) for the insertion of the actuator device (71 ) .

5. A brake caliper according to any one of the preceding claims, comprising an Insulation Displacement Contact ( IDC) system for the electrical power supply of a lamellar pack (37 ) of the stator (35) .

6. A brake caliper according to claim 5, wherein the IDC system includes three axial forks (43) connected on one side to the respective high power terminals (31 ) of the cover ( 19) and on the other side inserted into a respective pocket (44 ) of the stator (35) , wherein each pocket (44 ) is connected in turn to the winding of the stator (35) .

7. A brake caliper according to any one of the preceding claims, wherein the stator (35) comprises a pair of winding insulators (45) , for example a front insulator (45a) and a rear insulator (45b) .

8. A brake caliper according to any one of the preceding claims, wherein the stator (35) is keyed directly into the motor housing ( 13) , on a cylindrical stator keying surface ( 13' ) , partially placed on the partition wall ( 11 ) of the caliper body (3) .

9. A brake caliper according to any one of the precedingclaims, wherein the stator is of the segmented type .

10. A brake caliper according to any one of the preceding claims, wherein the stator (235) comprises pins (293) protruding axially at the rear, which engage a bearing housing (255) .

11. A brake caliper according to any one of the preceding claims, wherein the rotor (39) is supported by a front bearing (50) and a rear bearing (51 ) .

12. A brake caliper according to claim 11, wherein the front bearing (50 ) is supported in a bearing seat ( 57 ) of a bearing housing (55) made of drawn and / or bent sheet metal .

13. A brake caliper according to claim 11 or 12, wherein the front bearing (50) has an outer race (351 ) provided with one or more 0-rings (353) to ensure a grease tightness of the transmission device towards the motor .

14. A brake caliper according to any one of claims 11 to 13, wherein the rear bearing (51 ) is supported in a bearing compartment ( 19' ) obtained in the cover ( 19) .

15. A brake caliper according to any one of claims 11 to 14, wherein the front bearing (50) is axially stopped in place between a ridge of a rotor shaft (49) and a corrugated spring (53) .

16. A brake caliper according to any one of claims 11 to 14, wherein the rear bearing (51) is axially stopped inplace between a ridge of a rotor shaft ( 49 ) and a corrugated spring ( 53 ) .17 . A brake caliper according to any one of claims 11 to 15 , wherein the cover has a through hole for keying an inner race of the rear bearing ( 451 ) pre-assembled in a bearing support ( 455 ) on the rotor shaft ( 449 ) .18 . A brake caliper according to any one of the preceding claims , wherein the actuator device ( 71 ) comprises an actuator nut screw ( 73 ) , rotatably supported in the actuator housing ( 15 ) by means of a roller or needle cage ( 75 ) , said cage being keyed onto an actuator keying surface , and keyed onto a cylindrical actuator keying surface ( 15 ' ) , partially placed on the partition wall ( 11 ) of the caliper body ( 3 ) .

19. A brake caliper according to claim 18 , wherein the actuator device ( 71 ) comprises a force sensor ( 87 ) , sensitive to axial thrust applied by the actuator nut screw ( 73 ) , electrical ly connected to the electrical terminals ( 29 , 31 ) of the cover ( 19 ) .20 . A brake caliper according to claim 19 , wherein the actuator device ( 71 ) comprises a j oint ( 89 ) , carried by the head of the actuator screw ( 79 ) , and a thrust plate ( 91 ) , supported by the j oint ( 89 ) for discharging any radial reaction actions from the pad to the actuator screw ( 79 ) .21 . A brake caliper according to any one of the preceding claims , compris ing a transmission device ( 101 ) for transmitting torque from the motor ( 33 ) to the actuator device ( 71 ) .22 . A brake caliper according to claim 21 , wherein the transmission device ( 101 ) comprises at least one epicyclic reduction gear .

23. A brake caliper according to claim 22 , wherein the epicyclic reduction gear is coaxial to the rotor shaft ( 49 ) and consists of a sun gear, a plurality of planet gears ( 103 ) , a planet gear carrier ( 105 ) , and a crown ( 107 ) , keyed onto a cylindrical crown keying surface ( 13 ' ' ) , partially placed on the partition wall ( 11 ) of the caliper body ( 3 ) .24 . A brake caliper according to claim 22 or 23 , wherein the transmission device comprises two or more epicyclic reduction gears , having a single crown or several crowns for a single reduction gear, arranged in series .

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